12. A New Simulation Approach for the Fatigue Design of Highly Loaded Cast Iron Cylinder Heads

合集下载

2024年甘肃专升本考试真题英语

2024年甘肃专升本考试真题英语全文共3篇示例，供读者参考篇12024 Gansu College Entrance Examination for Adults English TestPart I Reading ComprehensionSection ADirections: In this section, there are four passages followed by questions or unfinished statements. For each of them, there are four choices marked A), B), C) and D). Choose the one that best completes the statement or answers the question.Passage 1A recent study found that children who spend more time outdoors have better mental health than those who spend more time indoors. The researchers interviewed over 1,000 children aged 8 to 12 and found that those who spent at least two hours a day in nature were happier and more positive than those who spent less time outside.1. According to the passage, what is the main finding of the study?A. Children prefer to spend more time indoors.B. Children who spend more time outdoors have better mental health.C. Too much time outdoors can negatively impact children's mental health.D. The researchers interviewed over 1,000 adults.2. How many children were interviewed in the study?A. 500B. 800C. 1,000D. 1,5003. Which age group was the study focused on?A. 5 to 10B. 8 to 12C. 12 to 16D. 15 to 184. According to the passage, how much time in nature is recommended for children?A. at least one hour a dayB. at least two hours a dayC. at least three hours a dayD. at least four hours a day5. What can be inferred from the passage?A. Children who spend more time indoors are happier.B. Children who spend less time outdoors are more positive.C. Spending time in nature can have a positive impact on mental health.D. The researchers did not find any correlation between time spent outdoors and mental health....Part II VocabularySection ADirections: Beneath each of the following sentences there are four choices marked A), B), C) and D). Choose the one that best completes the sentence.21. I can't believe how quickly time ________.A. goes byB. goes awayC. goes inD. goes on22. She tried to ________ her parents to buy her a new bike.A. convinceB. persuadeC. informD. suggest23. The meeting was ________ to begin at 9:00 a.m.A. consideredB. supposedC. thoughtD. planned24. I ________ the answer to the question without any hesitation.A. knewB. realizedC. recognizedD. identified25. It is essential to ________ a healthy diet in order to stay fit.A. maintainB. preserveC. sustainD. retain...Part III WritingDirections: For this part, you are allowed 30 minutes to write an essay on the topic "The Impact of Social Media on Relationships". You should write at least 150 words.The Impact of Social Media on RelationshipsSocial media has become an integral part of our daily lives, with millions of people using platforms such as Facebook, Instagram, and Twitter to connect with others. While social media has its benefits, it also has a significant impact on relationships.One of the key ways in which social media impacts relationships is through communication. While it allows people to stay in touch with friends and family across the globe, it can also create misunderstandings and conflicts. Misinterpreted messages or posts can lead to unnecessary arguments and hurt feelings.Furthermore, social media can also lead to jealousy and insecurity in relationships. Seeing your partner interact with other people online can trigger feelings of inadequacy and doubt. In extreme cases, social media can even lead to infidelity and trust issues....Overall, social media can have both positive and negative impacts on relationships. It is important for individuals to be mindful of how they use social media and to communicate openly with their partners to avoid misunderstandings and conflicts.Remember to proofread your essay for grammar and spelling errors before submitting it.(Word count: 2000+)篇2Title: 2024 Gansu College Entrance Exam for Adults (Specialized Bachelor's Degree) English ExamIntroduction:The Gansu College Entrance Exam for Adults, also known as the Specialized Bachelor's Degree Exam, is a highly competitive and challenging examination that allows adults to pursue higher education by enrolling in universities or colleges in Gansu province. The English exam is an essential part of this process, testing the candidates' proficiency in the English language. In this document, we will provide the 2024 English exam questions and answers for your reference and practice.2024 Gansu Specialized Bachelor's Degree English Exam Questions:Section 1: Reading ComprehensionRead the following passage and answer the questions that follow:Passage:Technology plays a vital role in our daily lives, revolutionizing the way we communicate, work, and learn. Whether it is the invention of the smartphone or the development of artificial intelligence, technology has the power to transform society and shape our future.Questions:1. According to the passage, what impact does technology have on society?2. How has technology changed the way we communicate?3. Give an example of a technological innovation mentioned in the passage.Section 2: Vocabulary and GrammarChoose the correct word or phrase to complete the sentences:1. The teacher asked the students to _______ their homework by tomorrow.a) hand in b) hand on c) hand out d) hand over2. _______ he studies hard, he won't pass the exam.a) Unless b) If c) Although d) Because3. The company _______ a new product next month.a) will launch b) would launch c) is launching d) has launchedSection 3: WritingWrite an essay of at least 250 words on the following topic: "The Impact of Social Media on Society."2024 Gansu Specialized Bachelor's Degree English Exam Answers:Section 1: Reading Comprehension1. Technology has the power to transform society and shape our future.2. Technology has changed the way we communicate by providing instant messaging and video calling.3. SmartphoneSection 2: Vocabulary and Grammar1. a) hand in2. a) Unless3. a) will launchSection 3: Writing(Students' answers may vary, but the key points should include the influence of social media on communication, relationships, and privacy.)In conclusion, the 2024 Gansu Specialized Bachelor's Degree English Exam is a rigorous test that assesses candidates' English language skills and knowledge. By practicing with the provided questions and answers, candidates can better prepare themselves for success in the exam and their future academic pursuits. Good luck to all the aspirants!篇3Title: 2024 Gansu Adult College Entrance Examination English TestIntroduction:The Gansu adult college entrance examination is an important opportunity for adults in Gansu Province to further their education and improve their career prospects. The English test is a key component of the examination and requires candidates to demonstrate their proficiency in the English language. In this article, we will provide a sample of the 2024English test questions for the Gansu adult college entrance examination.2024 Gansu Adult College Entrance Examination English Test:Section 1: Reading ComprehensionRead the following passage and answer the questions that follow:In recent years, there has been a growing awareness of the importance of environmental conservation. People are becoming increasingly concerned about issues such as climate change, deforestation, and pollution. It is crucial that we take action to protect our planet for future generations.1. What is the main topic of the passage?A. The importance of environmental conservationB. The effects of climate changeC. Deforestation and pollutionD. The future of our planet2. Why is environmental conservation important?A. To protect our planet for future generationsB. To prevent climate changeC. To reduce pollutionD. All of the above3. What issues are people becoming increasingly concerned about?A. Climate change, deforestation, and pollutionB. The economy and unemploymentC. Education and healthcareD. Technology and innovationSection 2: Vocabulary and GrammarFill in the blanks with the appropriate words or phrases:4. The ____________ of global warming is becoming more and more evident.5. It is essential to ____________ the amount of waste we produce.6. The government has implemented ____________ to protect endangered species.Section 3: WritingWrite an essay of 300 words on the following topic:"Discuss the impact of climate change on the environment and what individuals can do to help combat it."Conclusion:The Gansu adult college entrance examination is an important opportunity for adults in Gansu Province to further their education and enhance their career prospects. The English test is a key component of the examination, testing candidates' proficiency in the English language. By preparing for and taking the 2024 English test, candidates can improve their chances of success in the examination and achieve their academic and career goals.。

Philosophical Transactions of the Royal Society London – A (2003) The Role of Social and C

The Role of Social and Cognitive Factors in the Emergence of Communication: Experiments in Evolutionary RoboticsDavide Marocco1,31 University of Calabria, Centro Interdipartimentale della Comunicazione Arcavacata di Rende, 87036Cosenza, Italydavidem@r.itAngelo Cangelosi22University of PlymouthInstitute of Neuroscienceand School of ComputingDrake Circus, PL4 8AAPlymouth, UKacangelosi@Stefano Nolfi33National Research CouncilInstitute of Cognitive Scienceand Technologies,Viale Marx 15, 00137Rome, Italynolfi@r.itAbstractEvolutionary robotics is a biologically inspired approach to robotics that is advantageous to studying the evolution of language. A new model for the evolution of language is presented. This model is used to investigate the interrelationships between communication abilities, namely linguistic production and comprehension, and other behavioral skills. For example, the model supports the hypothesis that the ability to form categories from direct interaction with an environment constitutes the ground for subsequent evolution of communication and language. A variety of experiments, based on the role of social and evolutionary variables in the emergence of communication, are described.1. IntroductionThe communication between autonomous agents, be they robots or simulated virtual agents, has recently attracted the interest of researchers from different fields. In engineering, the design and evaluation of communication systems is interesting due to its practical applications for agent-agent interaction and also for human-agent and human-robot communication (e.g. Lauria et al., 2002). For cognitive scientists, the development of computational models for the evolution of language permits the investigation of the role of sensorimotor, cognitive, neural and social factors in the emergence and establishment of communication and language (Cangelosi & Parisi, 2002).Studies on the emergence of communication are often based on synthetic methodologies such as adaptive behavior and artificial life (Steels, 1997; Kirby, in press). A group of autonomous agents interact via language games to exchange information about the external environment. Their coordinated communication system is not externally imposed by the researcher, but emerges from the interaction between agents. In such models, the levels of detail of the representation of the agents and of their environment can vary significantly. This constitutes a continuum between abstract point models, at one end, and situated, embodied robots at the other. At one extreme, only the essential communicative properties of the agents and the environment are simulated. For example, the environment can consist of a list of abstract “meanings”, and the agent consists of a function, or rule set, that maps these meanings to signals (e.g. Kirby, 2001; Oliphant, 1999). This approach is useful when one wants to study the dynamics of the auto-organization of lexicons and syntax and its dependence on single, pre-identified factors. An intermediate approach to language evolution is based on grounded simulation models (Harnad, 1990). The agents’ environment is modeled with a high degree of detail upon which emergent meanings can be directly grounded. Each simulated agent has a set of sensorimotor, cognitive and social abilities that allow it to build, through interaction, a functional representation of the environment and use it to communicate (e.g. Cangelosi, 2001; Cangelosi & Harnad, 2000; Hazlehurst & Hutchins, 1998). This type of models supports the investigation of the interaction amongst various abilities of the agents for the emergence of language and the grounding of communication symbols in the environment and the agent’s behavior.At the other end of the continuum, the communicative behavior of embodied and situated robots results from the dynamical interaction between its physical body, the nervous and cognitive system and the external physical and social environment (Beer, 1995). For example, robots can interact and communicate among themselves (e.g. Steels & Vogt, 1997; Quinn, 2001), with virtual Internet agents (Steels, 1999) and with humans (Steels & Kaplan, 2000). Such an approach permits the study of the interaction between the different levels of a behavioral system, that is from sensorimotor coordination to high-level cognition and social interaction.Amongst the robotic approaches to studying adaptive behavior, evolutionary robotics (Nolfi & Floreano, 2002) offers a series of advantages. Through evolutionary experiments, artificial organisms autonomously develop their behavior in close interaction with their environment. The main advantages of this approach are: (a) it involves systems that are embodied and situated (Brooks, 1991; Pfeifer and Scheier, 1999), and (b) it is an ideal framework for synthesizing robots whose behavior emerge from a large number of interactions among their constituent parts. This can be explained by considering that, in evolutionaryexperiments, robots are synthesized through a self-organization process based on random variation and selective reproduction where the selection process is based on the behaviors that emerge from the interactions among the robot's constituent elements and between these elements and the environment. This allows the evolutionary process to freely exploit interactions without the need to understand in advance the relation between interactions and emerging properties as it is necessarily required in other approaches that rely more on explicit design.For these reasons the evolutionary robotics approach has been successfully applied to the synthesis of robots able to exploit sensorimotor coordination (Nolfi, 2002); on-line adaptation (Nolfi and Floreano, 1999); body and brain co-evolution (Lipson and Pollack, 2000); competing and cooperative collective behaviors; (Nolfi and Floreano, 1998, Martinoli, 1999; Baldassarre, Nolfi, and Parisi, 2002).These advantageous aspects of evolutionary robotics are of particular importance for modeling the evolution of language and communication. Sensorimotor coordination, social interaction, evolutionary dynamics and the use of neural systems can all have a potential impact in the emergence of coordinated communication. In this paper, new experiments are presented that study the emergence of communication in evolutionary robotics models. They are based on recent work by Nolfi and Marocco (2002) for the emergence of sensorimotor categorization. Nolfi and Marocco evolved the control system of artificial agents that are asked to categorize objects with different shapes on the basis of tactile information. Each agents uses proprioceptive information to actively explore objects using a three-segment arm. In addition, the agent uses the activation of one output node of its neural network controller as input. Agents are selected only for their performance in discriminating (categorizing) the objects using this unit, not for their ability to explore them. This results in the emergence of an active tactile exploration strategy that differentiate between objects of different shapes. Nolfi and Marocco’s model is an example of explicit self-categorization.In this new model, the robotic agents share the explicit categorization of objects. That is, the activation of the output nodes is the signal (“name”) sent to another agent to instruct it on what to do with the object. Agents will be selected on their ability to manipulate objects correctly, not on their (linguistic) ability to name them correctly. A variety of experiments will test the role of different social and evolutionary variables. These will be used to analyze the role of sensorimotor, social and cognitive factors in the emergence of communication. The direct relations between behavioral and communication abilities, such us language production and comprehension, will also be discussed. 2. MethodThe behavior of each agent consists of exploration within the environment, on the basis of tactile information, and the communication, about the type of objects that are in it. The environment consists of an open three-dimensional space in which one of two different objects is present in each epoch (Figure 1). The two objects used in this simulation are asphere and a cube.Figure 1 – The arm and a spherical object.Figure 2 – A schematic representation of the arm.Agents are provided with a 3-segments arm with 6 degrees of freedom (DOF) and extremely course touch sensors (see Figure 2). Each segment consists in a basic structure of two cylindrical bodies and two joints. This is replicated for three times. The basic structure consists of a shorter body of radius 2.5 and length 3 and a longer body of the same radius and length 10 for the first two segments. The length of the third segment is 5. This shorter segment represents a fingerless hand. The two bodies of each segment are connected by means of a joint (i.e. the Joint E in the Figure) that allows only one DOF on axis Y, while the shorter body is connected at the floor, or at the longer body, by means of a joint (i.e. the Joint R) that provides one DOF on axis X. In practice, the Joint E allows to elevate and lower the connected segments and the Joint R allows to rotate them in both direction. Notice that Joint E is free to moves only in a range between 0 and π/2, just like a human arm that can bend the elbow solely in a direction. The rangeof Joint R is [–π/2, +π/2]. Gravity is {0, –1, 0}. Each actuator is provided with a corresponding motor that can apply a maximum force of 50. Therefore, to reach every position in the environment the control system has to appropriately control several joints and to deal with the constraints due to gravity.The sensory system consists of a simple contact sensor placed on each longer body that detects when this body collides with another, and two proprioceptive sensors that provide the current position of each joint.The controller of each individual consists of an artificial neural networks with 11 sensory neurons connected to 3 hidden neurons. These connect with 8 output neurons. The first 9 sensory neurons encode the angular position (normalized between 0.0 and 1.0) of the 6 DOF of the joints and the state of the three contact sensors located in the three corresponding segments of the arm. The other 2 sensory neurons receive their input from the other agents. The first 6 motor neurons control the actuators of the corresponding joints. The output of the neurons is normalized between [0, +π/2] and [–π/2, +π/2] in the case of elevation or rotational joints respectively and is used to encode the desired position of the corresponding joint. The motor is activated so to apply a force (up to 50) proportional to the difference between the current and the desired position of the joint. The last 2 output neurons encode the signal to be communicated to the other agents. This works as a small winner-takes-all cluster, where the neuron with the highest activation is set to 1 and the other to 0.The activation state of internal neurons was updated accordingly to the following equations (output neurons were updated according to the logistic function):+=iij j jO w t()()1)1(11−−−+−+=j A j t jj j eO O ττ(1) 10≤≤j τWith Aj being the activity of the j th neuron (or the state of the corresponding sensor in the case of sensory neurons), tj the bias of the j th neuron, Wij the weight from the i th to the j th neuron, Oi the output of the i th neuron. Oj is the output of the j th neuron, τj the time constant of the j th neuron.Each individual was tested for 36 epochs, each epoch consisting of 150 sensorimotor cycles. At the beginning of each epoch the arm is fully extended. A spherical or a cubic object is placed in a random selected position in front of the arm. The position of the object is randomly selected between the following intervals: 15.0 <= X <= 25.0; Y = 7.5; –5.0 <= Z <= 5.0). The object is a sphere (15 units in diameter) during even epochs and a cube (15 units in side) during odd epochs so that each individual has to discriminate the same number of spherical and cubic objects during its lifetime.In addition to the proprioceptive information, agents also receive in input a 2-bit signal produced by some other agent in the population, such as the parent or any agent from the population (linguistic comprehension task). The protocol of interaction and communication between agents was systematically varied and is analyzed in section 3.Before they act as speaker, agents undergo a linguistic production task. That is, each agent is put in the environment and asked to interact with the object. The value of the two output neurons in the last cycle of the epoch is saved and used as the signal produced to “name” the object. A genetic algorithm is used to evolve the behavior of agents. The genotype of each agent consists of 81 parameters that include 67 weights, 11 biases, and 3 time constants. Each parameter is encoded with 8 bits. Weights and biases are normalized between –5.0 and 5.0, time constants are normalized between 0.0 and 1.0.The fitness rewards the behavior of the agent with the current object in the environment. Good communication behavior does not produce any fitness gain for the speaker. Following the behaviors evolved in Nolfi & Marocco’s (2002) simulation, the agent has to touch and stay in contact with one object (the sphere) and has to avoid as much as possible to touch the other object (cube). The fitness of individuals is computed by summing the number of cycles in which the agent touches the sphere or does not touch the cube. Fitness scores decrease for each cycle the agent touches the cube or when it does not touch the sphere.A population of 80 agents is used in each simulation. During selection, the 20 agents with the highest fitness (i.e. behavioral performance) reproduce and each make 4 offspring. The genotype of each offspring is then subject to mutation with an overall probability of 2%. That is, each bit has a 2% probability of being mutated, by generating a random binary value. There is generational overlap between the population of parents and that of new offspring. The first will only act as speakers and cannot reproduce anymore. The population of new offspring will be subject to the fitness test and will reproduce at the end of their lifetime. Evolutionary simulation of embodied robotic agents can be time consuming and computationally expensive. To reduce the time necessary to test individual behaviors and to model the real physical dynamics as accurately as possible, the rigid body dynamics simulation SDK of Vortex TM was used 1. This was linked to the EvoRobot simulator (Nolfi, 2000).3. ResultsThe simulation model was used to run a series of experiments on the role of various social and evolutionary variables in the emergence of shared communication. The first independent variable refers to the selection of speakers (SPEAKER) with two levels: Parent or All. In the first case, each agent receives communication signals only from its own parent. In the second level of the variable, each agent1/products/vortex/can receive signals from any individual of the previous population. This factor is aimed at investigating the role of different social groups of speakers in facilitating shared communication.The second independent variable manipulated during experiments consists in the time in which communication is allowed (COMMUNICATION) with two levels: From_0 and From_50. In the first case, agents were allowed to communicate from the initial random generation. In the second level of the variable, agents start to communicate between themselves only at generation 50, i.e. after they have evolved a good ability to touch/avoid the two objects. Through this variable it will be possible to investigate the initial behavioral and cognitive abilities necessary to evolve communication.For each of the 4 conditions (2 SPEAKER × 2 COMMUNICATION), 10 replications were executed, by changing the initial random population. Fifty generations were necessary to pre-evolve an optimal behavior of object manipulation to be used in the From_50 conditions. Table 1 reports the communication success in each condition in terms of good populations and percentage of good speaker in the population. The criterion for deciding whether a population has successfully evolved communication depends on the fact that, at the last generation, at least 50% of agents produce two signals that differentiate the two objects.Table 1 – Data on the emergence of communication in each experimental condition. The first line contains the number of populations (out of 10) where communication emerged. The second line contains the average percentage of good speakers for the 10 replications and the average for the best performing population (value between brackets).SPEAKER COMMUNICATIONFrom 0COMMUNICATIONFrom 50Parent# good pops % speakers (best pop)527% (75%)763% (100%)All# good pops % speakers (best pop)7% (20%)5% (27%)The results of the number of populations that evolve shared communication clearly show that it is only when the parents act as the speakers there is a selective pressure for the emergence and preservation of a shared communication system. In particular, 7 populations out of 10 reach a stable communication system when language is introduced after agents have learned to use both objects. Figure 3 shows the fitness curves and the proportion of good speaker in the best seed of the condition From_50 - Parent speaker.When communication is introduced directly from the initial random population, the probability of evolving a good language, together with a good behavior, is lower (5 populations out of 10). This advantage for evolving languages after the basic behavioral skills have evolved is similar to that observed by Cangelosi & Parisi (2001) in a grounded simulation model on the emergence of verbs and nouns.When agents listen to all individuals of the previous generation, no stable communication exists in the last generations. In fact, during evolution good lexicons sometimes emerge for a short time, but they are not maintained or further developed by the whole population. A temporary good lexicon is defined as the case in which at least 20% of agents use two different signals to name the two objects. In 8 of the 10 From_50 - All speaker populations, such temporary appearances of good signal production is observed. Figure 4 shows the best population in the From_50 - All speaker conditions. Here the longest period of good production only lasts for 17 generations,with a maximum peak of best language at 41%.Figure 3 – Data for the best population of the condition Parentspeaker - From_50.Figure 4 – Data for the best population in condition All speakers - From_50.The lexicon produced by agents in successful replications has been tested to investigate whether individuals actually use this language in a meaningful way, i.e. avoid the cube when the signal produced in response to the cube is used, and touch the sphere when the other signal is used. Figure 5 shows the behavior of an agent that interacts with the cube with or without language. This tests the linguistic comprehension ability of agents. The pictures on the left column (Figure 5 - left) show the behavior of the agent when no input signal is used. The agent needs to touch the cube, at least once (in cycle 95), to identify it as a cubeand then retract from it. The pictures on the right (Figure 5 - right) show the behavior of the agent when the signal “10” is used as additional input. This signal is produced by the parent organism at the end of the interaction with a cube. During this scene, the agent does not need to touch the cube at all because the signal “10” identifies it as a cube. The meaning of “10” can be interpreted as “cube”2, because the listener treats the object as a cube, and the speaker produces it after its interaction with a cube. When the signal “01” is used, the agent touches the object regardless of its shape. Inthis case, “01” has the meaning of “sphere”.Figure 5 – Agent’s interaction with the cube and test of linguistic understanding ability. Left column: Only the proprioceptive input is given to the agent. Right column: An additional communication signal is given as input. This is produced by another agent at the end of its interaction with a cube. Figures from the best individual of a From_50 - Parent speaker population.Fitness data shows that final scores in the 4 experimental conditions reflect the pattern of results on the emergence of successful communication. The two conditions with Parent speakers reach the highest fitness scores, with a significant2This signal can also be interpreted as the verb avoid , instead of as the noun cube . In fact, in this model it is not possible to distinguish between syntactic word classes (cf. Cangelosi & Parisi 2001 and Cangelosi 2001 for a discussion)advantage for the From_50 populations (e.g. average fitness of best individuals = 0.55; fitness peak in best population = 0.72) versus the From_0 population (average = 0.45, peak = 0.66). The baseline for the behavior without communication is the fitness at generation 50 of the From_50 simulation, before agents start to communicate (average = 0.44, peak = 0.52). Consider that the maximum hypothetical fitness score is 1. This can never be reached because, for example, at the beginning of each epoch some negative fitness cycles are always necessary for agents to reach the spherical object and start gaining fitness.4. DiscussionThere are several issues that can be discussed regarding these results, and what we can learn from the model. A series of questions will be used to analyze the results.Question 1: Is there any benefit to be in a population wheregood communication has emerged?Question 2: Is there any direct advantage to evolving agood linguistic comprehension ability?To answer the first question, it is possible to compare the fitness results in the simulations where no shared communication emerged, and those where good communication systems evolved. The condition in which communication emerged more frequently (From_50, Parent speaker) will be used as example. In this condition, 7 populations evolved good languages, whilst 3 did not. Figure 6 shows the average fitness of the good communication populations (thick lines) and that of the no communication populations (thin lines). The chart clearly shows that agents who use communication reach fitness values that are higher that those not communicating. This is true both for the fitness of the best individual and for that of the whole population. For example, at the final generation the average fitness of the 7 successful communication replications is 0.35, while it is 0.21 for the 3 unsuccessful populations. Moreover, the fitness in these 3 populations remains relatively constant during the simulation. In the first 50 generations after communication is permitted (i.e. from 50 to 100), there is no increase and the average fitness at generation 100 is very similar to that at generation 50. In the remaining generations, the agents gain some extra fitness points, which are due to the continuation of the evolutionary algorithm search.The extra fitness gain in populations that evolve communication is easily explained by the direct benefits for the behavior (i.e. fitness) of using two different signals: one for the cube, and one for the sphere. As already shown in Figure 5, during the interaction with a cube the input of its “name” produces significant improvements to behavioral performance. Agents do not need to touch the object to recognize it, and therefore do not lose fitness due to such exploratory behavior. In addition, they gain fitness in every cycle. There is also some benefit for the use of the signal for the sphere. If an agent initially is told that there is a spherical object in the environment, it can go directlytowards the object and touch it, without having to use some interaction cycles for recognizing the object as a non cube.The previous explanations also answer the second question, since they identify a direct adaptive advantage for evolving a good comprehension ability.Figure 6 – Average fitnesses of the conditions From_50 - Parent speaker. Thick lines refer to the average fitness of the 7 replications where good communication emerged (continuous line for the best agent and dotted line for the average of all agents). Thin lines refer to the average fitness of the 3 replications where no shared communication emerged.Question 3: Is there any “direct” advantage to evolving good linguistic production abilities?This question is more difficult to answer. In fact, there seems to be no direct fitness advantage to the agents to speaking well. Individuals only update their fitness when they hear others speaking. When agents act as speakers, some have already reproduced, whilst the others have not been selected at all. In the condition Parent speaker, agents only speak to their own children. Therefore, the kinship relationship can partially explain this apparent altruistic behavior and the indirect fitness gain for the common genes shared by the parent and its offspring (e.g. Ackley & Littman, 1994). The benefits of kin selection can also explain the successful evolution of communication in the Parent speaker versus the All speaker conditions. However, there is another important phenomenon to be considered. In the Parent speaker conditions, the linguistic input to each listener is constant, since its parent will always use the same signal for the same object. In addition, when the parent is a good speaker (i.e. it uses two different signals to refer to the two objects), its signals are more reliable. The child can then try to use them to improve its fitness performance. In the All speaker conditions, the high variability of the linguistic input coming from all agents of previous generation can be too unreliable, and agents will tend to ignore it.In the All speaker conditions, some communication abilities also emerge, although the number of good speakers never reaches the critical amount needed to allow it to remain stable until the end of the simulation (cf. Figure 4).In addition, in the Parent speaker conditions, there are threecases when shared communication does not evolve. According to the altruistic, kin selection explanation, allParent speaker populations should evolve communicationbecause of it indirect adaptive advantage. The fact that this does not always happen raises the issues of understanding the relation between linguistic comprehension/productionabilities and other behavioral/cognitive abilities (question4), and the identification of factors that cause and favor the emergence of shared communication (question 5). First, thedata in Table 1 indicates that it is easier to evolve goodcommunication when language is introduced after the pre-evolution of good behavioral capacities (7 out of 10 populations) than when agents are allowed to communicatefrom the initial generation (5 out of 10 seeds). In addition,the onset of effective communication (i.e. when at least 20% of agents speak well) is much earlier in the From_50 populations (on average after 16 generations) that in theFrom_0 simulations (on average after 41 generations). Thisdata is consistent with Cangelosi and Parisi’s (2001) model on the evolution of syntactic languages. This researchshowed that agents learn languages more efficiently whencommunication is introduced after the pre-evolution of goodbehavioral skills. Effectively, the pre-evolution of good behavior “prepares” a cognitive ground upon which goodlinguistic abilities can start to develop. Analyses of thecategorical perception effects in language learning models have shown that language uses and modifies the space of similarities between members of different perceptual andlinguistic categories (Cangelosi & Harnad, 2000). Question 4: What is the relation between comprehension,production and behavioral abilities? Question 5: What are the underlying factors that cause andfavor the emergence of communication?To understand better the relations betweencommunication abilities and behavioral skills, thecorrelations between fitness scores and a measure of the quality of produced language have been computed. Figure 7and 8 present the averages of the fitness curves, theproportions of good speakers (i.e. language index), thefitness/language correlation r all for the whole population, and the fitness/language correlation r best for the best 20agents. Figure 7 refers to the 7 successful populations of the From_50 - Parent speaker condition. Figure 8 refers to data from the remaining 3 populations without communication.For the computation of the language index based on theproportion of good speakers, an agent is classified as goodspeaker when it produces two opposite signals respectively for the two objects in at least half of the 36 epochs. ThePearson r correlations index was used.Overall, the two figures show that the correlationbetween the fitness of all agents and their language production index is positive and quite high (r all ≈ 0.5) after good communication emerges. This can explain themaintenance of good communication, since it reflects a link。

ADVISOR软件的混合仿真方法

第22卷　第2期计　算　机　仿　真2005年2月文章编号:1006-9348(2005)02-0203-04ADVISOR软件的混合仿真方法张翔,赵韩,钱立军,张炳力(合肥工业大学机械与汽车工程学院,安徽合肥230009)摘要:该文首先介绍了前向仿真方法和后向仿真方法,分析了其工作原理和优缺点。

接着描述了美国电动汽车仿真软件ADVIS OR的混合仿真方法,它是以后向仿真方法为主,前向仿真方法为辅的混合仿真方法。

然后以一混合动力汽车模型为例,分析了ADVIS OR的工作原理。

最后具体分析了一个典型仿真模块—车轮模块的模型,比较了其中的前向路径与后向路径的差异,具体说明了混合仿真方法的实现。

该文对ADVIS OR软件的应用具有参考作用。

关键词:电动汽车;车辆;汽车;仿真中图分类号:TP3;U4 文献标识码:ACombined B ackw ard/Forw ard Simulation Approach in the A DVISORZHANG X iang,ZHAO Han,QI AN li-jun,ZHANG Bing-li(School of Mechanical and Autom otive Engineering,Hefei University of T echnology,Hefei Anhui230009,China) ABSTRACT:This paper firstly introduces the backward-facing approach and forward-facing approach and analyses theirsimulation principle and points out advantages and disadvantages in tw o methods above.Then describes the hybrid back2ward/forward approach in the American electric vehicle simulation s oftware ADVIS OR,in which the backward approach isthe main role and the forward approach is similar to the backward approach.In the end,the principle of simulation of theADVIS OR is described by dem onstrating a hybrid electric vehicle m odel,and the m odel of wheel/axle that is a typic m odulein ADVIS OR is analyzed.Based on those examples,this paper gives the differences between backward approach and forwardapproach in ADVIS OR.This a g ood reference for the application of ADVIS OR.KE YWOR DS:E lectric vehicle;Vehicle;Autom obile;S imulation1　引言ADVIS OR是由美国可再生能源实验室在Matlab 和S imulink 软件环境下开发的电动汽车仿真软件。

A New Approach to Pipeline FFT Processor

A New Approach to Pipeline FFT ProcessorShousheng He and Mats TorkelsonDepartment of Applied Electronics,Lund UniversityS-22100Lund,SWEDENemail:he@tde.lth.se;torkel@tde.lth.se—A new VLSI architecture for real-time pipeline FFT processor is proposed.A hardware oriented radix-22algorithm is derived by integrating a twiddle factor decomposition technique in the divide and con-quer approach.Radix-22algorithm has the same multi-plicative complexity as radix-4algorithm,but retains the butterﬂy structure of radix-2algorithm.The single-path delay-feedback architecture is used to exploit the spa-tial regularity in signalﬂow graph of the algorithm.For length-DFT computation,the hardware requirement of the proposed architecture is minimal on both dominant components:log41complex multipliers and1 complex data memory.The validity and efﬁciency of the architecture have been veriﬁed by simulation in hardware description language VHDL.I.I NTRODUCTIONPipeline FFT processor is a speciﬁed class of processors for DFT computation utilizing fast algorithms.It is characterized with real-time,non-stopping processing as the data sequence passing the processor.It is an2non-optimal approach with23,since the area lower bound is. However,as it has been speculated[1]that for real-time pro-cessing whether a new metric should be introduced since it is necessarily non-optimal given the time complexity of. Although asymptotically almost all the feasible architectures have reached the area lower bound[2],the class of pipeline FFT processors has probably the smallest“constant factor”among the approaches that meet the time requirement,due to its least number,log,of Arithmetic Elements(AE). The difference comes from the fact that an AE,especially the multiplier,takes much larger area than a register in digital VLSI implementation.It is also interesting to note the at leastΩlog AEs are necessary to meet the real-time processing requirement due to the computational complexity ofΩlog for FFT al-gorithm.Thus it has the nature of“lower bound”for AE requirement.Any“optimal”architecture for real-time pro-cessing will likely haveΩlog AEs.Another major area/energy consumption of the FFT pro-cessor comes from the memory requirement to buffer the in-put data and the intermediate result for the computation.For large size transform,this turns out to be dominating[3,4]. Although there is no formal proof,the area lower bound indi-cates that the the“lower bound”for the number of registers is likely to beΩ.This is obviously true for any architecture implementing FFT based algorithm,since the butterﬂy atﬁrst stage has to take data elements separated distance away from the input sequence,where is a small constant integer, or the“radix”.Putting above arguments together,a pipeline FFT proces-sor has necessarilyΩlog AEs andΩcomplex word registers.The optimal architecture has to be the one that reduces the“constant factor”,or the absolute number of AEs (multipliers and adders)and memory size,to the minimum. In this paper a new approach for real-time pipeline FFT pro-cessor,the Radix-22Single-path Delay Feedback,or R22SDF architecture will be presented.We will begin with a brief re-view of previous approaches.A hardware oriented radix-22 algorithm is then developed by integrating a twiddle factor decomposition technique in divide and conquer approach to form a spatially regular signalﬂow graph(SFG).Mapping the algorithm to the cascading delay feedback structure leads to the the proposed architecture.Finally we conclude with a comparison of hardware requirement of R22SDF and several other popular pipeline architectures.II.P IPELINE FFT PROCESSOR ARCHITECTURES Before going into details of the new approach,it is beneﬁcial to have a brief review of the various architectures for pipeline FFT processors.To avoid being inﬂuenced by the sequence order,we assume that the real-time processing task only re-quires the input sequence to be in normal order,and the output is allowed to be in digit-reversed(radix-2or radix-4)order, which is permissible in such applications such as DFT based communication system[5].We also stick to the Decimation-In-Frequency(DIF)type of decomposition throughout the discussion.The architecture design for pipeline FFT processor had been the subject of intensive research as early as in70’s whenreal-time processing was demanded in such application as radar signal processing [6],well before the VLSI technology had advanced to the level of system integration.Several architectures have been proposed over the last 2decades since then,along with the increasing interest and the leap forward of the technology.Here different approaches will be put into functional blocks with uniﬁed terminology,where the additive butterﬂy has been separated from multiplier to show the hardware requirement distinctively,as in Fig.1.The control and twiddle factor reading mechanism have been also omitted for clarity.All data and arithmetic operations are complex,and a constraint that is a power of 4applies.BF4BF4BF43x4BF43x13x163x64BF4C4C48C48321123124412163248C416324864128192BF4BF4BF4BF4BF4BF4BF4DC6x64DC6x16DC6x4DC6x1C2C2C242211C284BF2BF2BF2BF2jBF28BF24BF22BF21j(i). R2MDC(N=16)(ii). R2SDF(N=16)(iii). R4SDF(N=256)(iv). R4MDC(N=256)(v). R4SDC(N=256)Figure 1:Various schemes for pipeline FFT processorR2MDC:Radix-2Multi-path Delay Commutator [6]was probably the most straightforward approach for pipeline implementation of radix-2FFT algorithm.The input se-quence has been broken into two parallel data stream ﬂow-ing forward,with correct “distance”between data elements entering the butterﬂy scheduled by proper delays.Both butterﬂies and multipliers are in 50%utilization.log 22multipliers,log 2radix-2butterﬂies and 322reg-isters (delay elements)are required.R2SDF:Radix-2Single-path Delay Feedback [7]uses the registers more efﬁciently by storing the butterﬂy output in feedback shift registers.A single data stream goes through the multiplier at every stage.It has same number ofbutterﬂy units and multipliers as in R2MDC approach,but with much reduced memory requirement:1registers.Its memory requirement is minimal.R4SDF:Radix-4Single-path Delay Feedback [8]was pro-posed as a radix-4version of R2SDF,employing CORDIC 1iterations.The utilization of multipliers has been increased to 75%due to the storage of 3out of radix-4butterﬂy out-puts.However,the utilization of the radix-4butterﬂy,which is fairly complicated and contains at least 8com-plex adders,is dropped to only 25%.It requires log 41multipliers,log 4full radix-4butterﬂies and storage of size 1.R4MDC:Radix-4Multi-path Delay Commutator [6]is a radix-4version of R2MDC.It has been used as the ar-chitecture for the initial VLSI implementation of pipeline FFT processor [3]and massive wafer scale integration [9].However,it suffers from low,25%,utilization of all com-ponents,which can be compensated only in some special applications where four FFTs are being processed simul-taneously.It requires 3log 4multipliers,log 4full radix-4butterﬂies and 524registers.R4SDC:Radix-4Single-path Delay Commutator [10]uses a modiﬁed radix-4algorithm with programable 14radix-4butterﬂies to achieve higher,75%utilization of multipliers.A combined Delay-Commutator also reduces the memory requirement to 22from 521,that of R4MDC.The butterﬂy and delay-commutator become relatively compli-cated due to programmability requirement.R4SDC has been used recently in building the largest ever single chip pipeline FFT processor for HDTV application [4].A swift skimming through of the architectures listed abovereveals the distinctive merits of the different approaches:First,the delay-feedback approaches are always more efﬁ-cient than corresponding delay-commutator approaches in terms of memory utilization since the stored butterﬂy output can be directly used by the multipliers.Second,radix-4algo-rithm based single-path architectures have higher multiplier utilization,however,radix-2algorithm based architectures have simpler butterﬂies which are better utilized.The new approach developed in following sections is highly motivated by these observations.III.R ADIX -22DIF FFT ALGORITHMBy the observations made in last section the most desirable hardware oriented algorithm will be that it has the same number of non-trivial multiplications at the same positions in the SFG as of radix-4algorithms,but has the same butterﬂy structure as that of radix-2algorithms.Strictly speaking,al-gorithms with this feature is not completely new.An SFG1TheCoordinate Rotational Digital Computerwith a complex “bias”factor had been obtained implicitly as the result of constant-rotation/compensation procedure using restricted CORDIC operations [11].Another algorithm com-bining radix-4and radix-‘42’in DIT form has been used to decrease the scaling error in R2MDC architecture,without altering the multiplier requirement [12].The clear derivation of the algorithm in DIF form with perception of reducing the hardware requirement in the context pipeline FFT processor is,however,yet to be developed.To avoid confusing with the well known radix-24split radix algorithm and the mixed radix-‘42’algorithm,the notion of radix-22algorithm is used to clearly reﬂect the structural relation with radix-2algorithm and the identical computational requirement with radix-4algorithm.The DFT of size is deﬁned by1(1)where denotes the th primitive root of unity,withits exponent evaluated modulo .To make the derivation of the new algorithm clearer,consider the ﬁrst 2steps of decomposition in the radix-2DIF FFT together.Applying a 3-dimensional linear index map,2142312243(2)the Common Factor Algorithm (CFA)has the form of122431301201102142321423122434130120122342314232243(3)where the butterﬂy structure has the form of12423423114232If the expression within the braces of eqn.(3)is to be com-puted before further decomposition,an ordinary radix-2DIF FFT results.The key idea of the new algorithm is to pro-ceed the second step decomposition to the remaining DFTcoefﬁcients,including the “twiddle factor”4231,to exploit the exceptional values in multiplication before the next butterﬂy is constructed.Decomposing the composite twiddle factor and observe that423122432342122312243321223122433(4)Substituting eqn.(4)in eqn.(3)and expand the summation with index 2.After simpliﬁcation we have a set of 4DFTs of length 4,122434131233122334(5)where123is expressed in eqn.(6).IBF 069W W W 1323W W W W W W W W W 02460N/4 DFT(k1=0, k2=0)N/4 DFT (k1=0, k2=1)N/4 DFT (k1=1, k2=0)N/4 DFT X(0)X(8)X(4)X(12)X(2)X(10)X(6)X(14)X(1)X(9)X(5)X(13)X(3)X(11)X(7)X(15)(k1=1, k2=1)x(0)x(1)x(2)x(3)x(4)x(5)x(6)x(7)x(8)x(9)x(10)x(11)x(12)x(13)x(14)x(15)IIBF -j -j -j -jFigure 2:Butterﬂy with decomposed twiddle factors.eqn.(6)represents the ﬁrst two stages of butterﬂies with only trivial multiplications in the SFG,as BF I and BF II in Fig.2.After these two stages,full multipliers are required to compute the product of the decomposed twiddle factor3122in eqn.(5),as shown in Fig.2.Note the order ofthe twiddle factors is different from that of radix-4algorithm.Applying this CFA procedure recursively to the remainingDFTs of length4in eqn.(5),the complete radix-22DIF FFT algorithm is obtained.An 16example is shown in Fig.3where small diamonds represent trivial multiplica-tion by 4,which involves only real-imaginary swapping and sign inversion.Radix-22algorithm has the feature that it has the same mul-tiplicative complexity as radix-4algorithms,but still retains the radix-2butterﬂy structures.The multiplicative opera-tions are in a such an arrangement that only every other stage has non-trivial multiplications.This is a great structural ad-vantage over other algorithms when pipeline/cascade FFT architecture is under consideration.IV .R22SDF ARCHITECTUREMapping radix-22DIF FFT algorithm derived in last section to the R2SDF architecture discussed in section II.,a new archi-tecture of Radix-22Single-path Delay Feedback (R22SDF)approach is obtained.123BF I31132122BF I3411334BF II(6)IBF x(0)x(1)x(2)x(3)x(4)x(5)x(6)x(7)x(8)x(9)x(10)x(11)x(12)x(13)x(14)x(15)X(0)X(8)X(4)X(12)X(2)X(10)X(6)X(14)X(1)X(9)X(5)X(13)X(3)X(11)X(7)X(15)IIBF BF BF IIIIV69W W 1323W W W W W W W 246-j -j -j -j-j-j -j-jFigure 3:Radix-22DIF FFT ﬂow graph for16Fig.5outlines an implementation of the R22SDF archi-tecture for 256,note the similarity of the data-path to R2SDF and the reduced number of multipliers.The imple-mentation uses two types of butterﬂies,one identical to that in R2SDF,the other contains also the logic to implement the trivial twiddle factor multiplication,as shown in Fig.4-(i)(ii)respectively.Due to the spatial regularity of Radix-22algo-rithm,the synchronization control of the processor is very simple.A log 2-bit binary counter serves two purposes:synchronization controller and address counter for twiddle factor reading in each stages.With the help of the butterﬂy structures shown in Fig.4,the scheduled operation of the R22SDF processor in Fig.5is as follows.On ﬁrst 2cycles,the 2-to-1multiplexors in the ﬁrst butterﬂy module switch to position “0”,and the butterﬂy is idle.The input data from left is directed to the shift registers until they are ﬁlled.On next 2cycles,the multiplexors turn to position “1”,the butterﬂy computes a 2-point DFT with incoming data and the data stored in the shift registers.12122,02(7)The butterﬂy output 1is sent to apply the twiddle fac-tor,and 12is sent back to the shift registers to be “multiplied”in still next 2cycles when the ﬁrst half of the next frame of time sequence is loaded in.The operation of the second butterﬂy is similar to that of the ﬁrst one,except the “distance”of butterﬂy input sequence are just 4and the trivial twiddle factor multiplication has been implemented by real-imaginary swapping with a commutator and controlledadd/subtract operations,as in Fig.4-(ii),which requires two bit control signal from the synchronizing counter.The data then goes through a full complex multiplier,working at 75%utility,accomplishes the result of ﬁrst level of radix-4DFT word by word.Further processing repeats this pattern with the distance of the input data decreases by half at each consec-utive butterﬂy stages.After 1clock cycles,The complete DFT transform result streams out to the right,in bit-reversed order.The next frame of transform can be computed without pausing due to the pipelined processing of each stages.(i).BF2I(ii).BF2IIFigure 4:Butterﬂy structure for R22SDF FFT processor In practical implementation,pipeline register should be in-serted between each multiplier and butterﬂy stage to improve the performance.Shimming registers are also needed for control signals to comply with thus revised timing.The la-tency of the output is then increased to 13log 41without affecting the throughput rate.V .C ONCLUSIONIn this paper,a hardware-oriented radix-22algorithm is de-rived which has the radix-4multiplicative complexity but re-tains radix-2butterﬂy structure in the SFG.Based on this algo-rithm,a new,efﬁcient pipeline FFT architecture,the R22SDF architecture,is put forward.The hardware requirement of proposed architecture as compared with various approaches is shown in Table 1,where not only the number of complexx(n)W1(n)12864BF2I BF2II s sW2(n)W3(n)57643210clkt 3216BF2I BF2II s s84BF2I BF2II s sBF2I 2BF2II 1X(k)s st t t Figure 5:R22SDF pipeline FFT architecture for256multipliers,adders and memory size but also the control com-plexity are listed for comparison.For easy reading,base-4logarithm is used whenever applicable.It shows R22SDF has reached the minimum requirement for both multiplier and the storage,and only second to R4SDC for adder.This makes it an ideal architecture for VLSI implementation of pipeline FFT processors.Table 1:Hardware requirement comparisonmultiplier #adder #memory size control R2MDC 2log 414log 4322simple R2SDF 2log 414log 41simple R4SDF log 418log 41medium R4MDC 3log 418log 4524simple R4SDC log 413log 422complex R22SDFlog 414log 41simpleThe architecture has been modeled with hardware descrip-tion language VHDL with generic parameters for transform size and word-length,using ﬁxed point arithmetic and a com-plex array multiplier implemented with distributed arithmetic.The validity and efﬁciency of the proposed architecture has been veriﬁed by extensive simulation.R EFERENCES[1] C.D.Thompson.Fourier transform in VLSI.IEEE Trans.Comput.,C-32(11):1047–1057,Nov.1983.[2]S.He and M.Torkelson.A new expandable 2D systolic arrayfor DFT computation based on symbiosis of 1D arrays.In Proc.ICA 3PP’95,pages 12–19,Brisbane,Australia,Apr.1995.[3] E.E.Swartzlander,W.K.W.Young,and S.J.Joseph.Aradix 4delay commutator for fast Fourier transform processor implementation.IEEE J.Solid-State Circuits ,SC-19(5):702–709,Oct.1984.[4] E.Bidet,D.Castelain,C.Joanblanq,and P.Stenn.A fastsingle-chip implementation of 8192complex point FFT.IEEE J.Solid-State Circuits ,30(3):300–305,Mar.1995.[5]M.Alard and ssalle.Principles of modulation and channelcoding for digital broadcasting for mobile receivers.EBU Review ,(224):47–69,Aug.1987.[6]L.R.Rabiner and B.Gold.Theory and Application of DigitalSignal Processing .Prentice-Hall,Inc.,1975.[7] E.H.Wold and A.M.Despain.Pipeline and parallel-pipelineFFT processors for VLSI implementation.IEEE -put.,C-33(5):414–426,May 1984.[8] A.M.Despain.Fourier transform computer using CORDICiterations.IEEE put.,C-23(10):993–1001,Oct.1974.[9] E.E.Swartzlander,V .K.Jain,and H.Hikawa.A radix 8waferscale FFT processor.J.VLSI Signal Processing ,4(2,3):165–176,May 1992.[10]G.Bi and E.V .Jones.A pipelined FFT processor for word-sequential data.IEEE Trans.Acoust.,Speech,Signal Process-ing ,37(12):1982–1985,Dec.1989.[11] A.M.Despain.V ery fast Fourier transform algorithms hard-ware for implementation.IEEE put.,C-28(5):333–341,May 1979.[12]R.Storn.Radix-2FFT-pipeline architecture with raducednoise-to-signal ratio.IEE Proc.-Vis.Image Signal Process.,141(2):81–86,Apr.1994.。

高三英语科学前沿动态引人关注单选题30题及答案

高三英语科学前沿动态引人关注单选题30题及答案1.The new technology, known as AI, is changing our lives rapidly. Which of the following is NOT an application of AI?A.Face recognitionB.V oice assistantC.Manual laborD.Autonomous driving答案：C。

本题考查对人工智能（AI）应用的了解。

选项A“Face recognition”（人脸识别）、选项B“V oice assistant”（语音助手）和选项D“Autonomous driving”（自动驾驶）都是人工智能的常见应用。

而选项C“Manual labor” 体力劳动）并非人工智能的应用。

2.In the field of scientific research, quantum computing is considereda revolutionary technology. What is the main advantage of quantum computing over traditional computing?A.Higher speedB.Lower costC.Smaller sizeD.Easier operation答案：A。

本题考查量子计算的优势。

量子计算相比传统计算的主要优势是更高的速度。

选项B“Lower cost” 更低成本）、选项C“Smaller size”（更小尺寸）和选项D“Easier operation”（更容易操作）都不是量子计算的主要优势。

3.The development of 5G technology has brought many changes. Which of the following is NOT a feature of 5G?A.High speedB.Low latencyC.Narrow bandwidthD.Massive connectivity答案：C。

clarify汇总

Sliding Spotlight SAR1Converse Beam Cross Sliding Spotlight SAR2TerraSAR-X,New Formulation of the Extended Chirp Scaling Algorithm3Hybrid Bistatic(双基地),in the Double Sliding Spotlight Mode 4SPACEBORNE/AIRBORNE（星载/机载）,BISTATIC5Spaceborne/Airborne Hybrid Bistatic SAR,Wavenumber-Domain(波数域) Algorithm6Sliding Spotlight and TOPS SAR，Baseband Azimuth Scaling（基带方位尺度）7INVERSE SLIDING SPOTLIGHT IMAGING8KEY PARAMETERS IN SLIDING SPOTLIGHT SAR9A STUDY OF SAR SIGNAL ANALYSIS，SLIDING SPOTLIGHT MODE 10Azimuth Ambiguity of Phased Array11Anti-Jamming（抗干扰）Property12USING EXTENDED FREQUENCY（扩展频率）SCALING13MULTIPLE SAR MODES WITH BASEBAND AZIMUTH SCALING 14With PAMIR and TerraSAR-X—Setup, Processing, and Image Result15Two-Step Algorithm in Sliding Spotlight Space-borne16 Frequency-Domain，for Spaceborne/AirborneConfiguration17 KOMPSAT-5 SPOTLIGHT SAR PROCESSOR， USING FSA WITH CALCULATION OF EFFECTIVE VELOCITY18 Time-Frequency，High-Resolution19 A Special Point Target Reference Spectrum20 Hybrid（混合式） Bistatic SAR TerraPAMIR，Geometric Description and Point Target Simulation（几何描述与点目标仿真）21Using Azimuth Frequency De-ramping（方位频率去斜）22Sliding Spotlight，TOPS SAR Data，Without Subaperture （子孔径）23 EXTENDED THREE-STEP FOCUSING ALGORITHM24The Study of realization method（实现方法）25Double Sliding Spotlight Mode with TerraSAR-X and PAMIR Based on Azimuth Chirp Filtering26A Unified（统一的） Focusing Algorithm（UFA），Based on FrFT（fractional(分数) Fourier transform）27 A MULTI-MODE SPACE-BORNE,BASED ON SBRAS（Space-borne Radar Advance Simulator）（星载雷达超前模拟器）28PRESENCE OF SQUINT（下斜视）29Large-Scene，Multiple Channels in Azimuth30Full-Aperture Azimuth，for Beam Steering （光束控制）SAR31Beam Steering （光束控制）SAR Data Processing by a Generalized PFA32Multichannel，Ultrahigh-Resolution（超高分辨率） and Wide-Swath Imaging（宽测绘带成像）33A Multi-mode Space-borne SAR34Processing of Ultrahigh-Resolution Space-borne Sliding Spotlight SAR Data on Curved Orbit（曲线轨迹）35Multichannel Sliding Spotlight and TOPS Synthetic Aperture Radar Data36Burst Mode Synthetic Aperture Radar（突发模式合成孔径雷达）37Novel High-Order Range Model（新的高阶模型），Imaging Approach for High-Resolution LEO（低轨） SAR38FULL-APERTURE IMAGING ALGORITHM39Azimuth Resampling Processing for Highly Squinted （大斜视）Synthetic Aperture Radar Imaging With Several Modes40Full-Aperture SAR，Squinted Sliding-Spotlight Mode 41X-Band SAR，TerraSAR-X，Next Generation and World SAR Constellation（一系列）42Multichannel Full-aperture，Beam Steering SAR43MONITORING THE DEFORMATION（变形监测） OF SHUPING LANDSLIDE（树坪滑坡）44USING A RANDOMLY STEERED SPOTLIGHT（随机转向聚焦）45THREE-STEP FOCUSING ALGORITHM（三步聚焦算法）ON SPATIAL VARIATION CHARACTERISTIC(空间变化特征)46 ATTITUDE STEERING STRATEGY(态度转向战略)，AGILE SMALL SAR SATELLITE（敏捷小卫星）47A REFINED GEOMETRIC（几何） CORRECTION ALGORITHM FOR SPOTLIGHT AND SLIDING48EFFECTS OF PRF VARIATION ON SPACEBORNE SAR IMAGING 49Image Formation Processing，With Stepped Frequency Chirps50Fast processing of very high resolution and/or very long range airborne SAR images.51TerraSAR-X Staring52Imaging for MIMO（Multiple-input/output） Sliding Spotlight53An Azimuth Resampling,Highly Squinted Sliding Spotlight and TOPS SAR54Beam Steering SAR Data Processing By a Generalized PFA（polar formation algorithm）极坐标格式算法55 computational efficient high resolution algorithm56 An Efficient Approach With Scaling Factors(变标因子) for TOPS-Mode SAR Data FocusingTOPS1TOPS-Mode Raw Data Processing with CSA2New DOA(波达方向) Estimator for Wideband Signals3Extended Chirp Scaling4Processing of Sliding Spotlight and TOPS SAR Data Using Baseband Azimuth Scaling5TerraSAR-X，Mode Design and Performance Analysis6Multichannel Azimuth Processing，ScanSAR（扫描式雷达）and TOPS7Resolution Improvement of Wideband DOA Estimation “Squared-TOPS”(方顶)8INVESTIGATIONS ON TOPS INTERFEROMETRY（干涉测量法） WITH TERRASAR-X9Efficient Full Aperture Processing10TOPS Interferometry（干涉测量法）with TerraSAR-X.11TOPS Sentinel-1 and TerraSAR-X Processor Comparison仿真数据12An Efficient Approach With Scaling Factors13Sliding Spotlight and TOPS SAR Data Processing Without Subaperture（子孔径）14Using the Moving Band Chirp Z-Transform15EXTENDED THREE-STEP FOCUSING ALGORITHM16Scalloping（扇形） Correction in TOPS Imaging Mode SAR Data17 重复18TOPS Mode Raw Data Generation From Wide-Beam SAR Imaging Modes19An Azimuth Frequency Non-Linear Chirp Scaling(FNCS) Algorithm for TOPS SAR Imaging With High Squint Angle 20Using Chirp Scaling Algorithm21Multichannel Sliding Spotlight and TOPS Synthetic Aperture Radar Data22A COMBINED MODE OF TOPS AND INVERSE TOPS FOR MECHANICAL BEAM STEERING（机械波束转向） SPACE-BORNE SAR 组合模式23on Full-Aperture Multichannel Azimuth Data Processing 24OPERATIONAL STACKING（操作层）OF TERRASAR-X SCANSAR（扫描雷达） AND TOPS DATA25SIGNAL PROPERTIES（信号特性） OF TOPS-BASED NEAR SPACE SLOW-SPEED SAR26DOPPLER-RELATED FOCUSING ASPECTS27Squinted TOPS SAR Imaging Based on Modified Range Migration Algorithm and Spectral Analysis（改进范围迁移算法及频谱分析）28Doppler-Related Distortions in TOPS SAR Images（多普勒相关的扭曲）29A Subaperture Imaging Algorithm to Highly Squinted TOPS SAR Based on SPECAN and Deramping（处理与去斜）30An Azimuth Resampling based Imaging Algorithm for Highly Squinted Sliding Spotlight and TOPS SAR三、●MOTION COMPENSATION●Modification of SAR Step Transform●Precision SAR Processing Using Chirp Scaling●Highly Squinted Data Using a Chirp Scaling Approach withIntegrated Motion Compensation●Strip-Map（条形图）SAR Autofocus●HYBRID（混合）STRIP-MAP(带状地形图)/SPOTLlGHT SAR●Polarimetric SAR(极化SAR) for a Comprehensive TerrainScene(地形场景) Using the Mapping and Projection Algorithm （用映射和投影的方法）9717 SIFFT SAR Processing Algorithm6982 Using Noninteger(非整数) Nyquist SVA（空间变迹） Technique3232PFA（极性坐标形式算法） algorithm●the Compensation of the SAR Range Cell Migration Basedon the Chirp Z-Transform●Chirp Scaling Approach，for Processing Squint Mode●HIGH RESOLUTION，USING RANDOM PULSE TIMING（随机脉冲定时）●Extended Chirp Scaling Algorithm（ECSA），Stripmap andScanSAR Imaging Modes●Motion compensation using SAR autofocus●Signal Properties of Spaceborne Squint-Mode SAR●the Extended Chirp Scaling(ECSA)●High Quality Spotlight SAR Processing AlgorithmDesigned for LightSAR Mission●rate allocation (速度分配) for Spotlight SAR Phase HistoryData Compression●An Extension to Range-Doppler SAR Processing to AccommodateSevere Range Curvature（适应严重的距离弯曲）●Frequency Scaling Algorithm（FSA）● Time-Varying Step-Transform Algorithm for High Squint SARImaging●Without azimuth oversampling in range migration algorithm ●High-speed focusing algorithm for circular syntheticaperture radar (C-SAR)●22 Two-step Spotlight SAR Data Focusing Approach●Motion Compensation●New Applications of Nonlinear Chirp Scaling●New Subaperture Approach,High Squint SAR● a Two-Step Processing Approach●Sub-aperture algorithm fo r motion compensation improvementin wide-beam SAR data processing●Multibaseline(多基线) ATI-SAR（Abstract-Advanced，along-track，interferometry干涉测量法）for Robust Ocean Surface Velocity Estimation in Presence of Bimodal（双峰的） Doppler Spectrum●FOPEN SAR Imaging Using UWB（超宽带） Step-Frequency（步进频率） and Random Noise Waveforms能够穿透叶簇并发现隐蔽于叶簇的目标，具有极其重要的军事作用。

新的雷达性能测试方法(英文)

New Methodology of Radar Performance MeasurementA. Kononov1, J.D. Jung1, Y.C. Shin11: STX RadarSys. Co., Ltd., 418, Chungduk-ri, Gusung-eup, Yongin-si, Kyonggi-do, 449-915, South KoreaAbstract: This paper is intended to introduce a new methodology of advanced radar performance measurement. The methodology is based on measuring the performance parameters, which are integrated criteria of the fitness for mission and which take into account the dynamic nature of radar mission. The radar mission accomplishment probability and the radar mission accomplishment time are proposed a s such criteria.The concept of a "super compact radar test range" is also introduced. This seems to be an adequate tool capable of simulating a near-real operating environment and evaluating the ability of radar to accomplish its mission. Keywords: phased array antenna, radar mission, radar performance measurement, target simulator, test range1. IntroductionModern and all the more future advanced radars are complex systems with multiple modes and employ phased array antennas and extensive signal and data processing. These radars often include a number of processing techniques that are becoming more and more sophisticated. For instance, operation of multifunction radar requires many adaptive features such as adaptive beamforming and waveforms selection, automatic multiple targets tracking in severe clutter and jamming environment.The advanced adaptive radars bring a number of problems in the specification and measurement of their performance [1]. The specification of performance of an adaptive system is very difficult and it might not even be obvious what we should understand by "performance". A particular problem is that dynamic performance is very difficult to quantify and measure. Certainly, traditional “static” parameters, such as maximum detection range against a given target, resolution in range, angles, and velocity, track initiation range and so on do not adequately define the radar capabilities [1]. Thus, a very important aspect of advanced radar systems procurement is the methodology of specifying and measuring radar performance.This paper is based on an idea that overall radar performance parameters should specify such values, which are the integrated quantitative measures of radar ability to perform its mission. The paper suggests that such parameters could be the radar mission accomplishment probability and radar mission accomplishment time. To estimate these parameters it is necessary to create real radar operational scenarios and to provide an accurate description and control of those conditions as well as their repeatability to permit an adequate statistical validation of radar performance.The conventional technologies of radar acceptance do not meet all the critical requirements to testing conditions. This paper proposes the concept of a new radar-testing tool entitled “Super Compact Radar Test Range” that meets all those requirements and allows the evaluation of radar mission accomplishment parameters. The conceptual structure of the super compact radar test range and its advantages and disadvantages are also considered.2. Conventional Technologies of Radar Testing The ability of the radar to meet its overall system performance specification should be evaluated by testing the entire system in a realistic operational environment. The basic goal of the test program is to estimate by measuring the radar performance parameters resulting from design and manufacturing and to relate them to the requirements imposed by the specification.The accuracy of radar performance measurement is a subject of great importance because of the direct impact it has on the correctness of judgment for the conformity of the achieved radar performance within the requirements. In order to get a statistically adequate estimation of radar performance there must be ensured the possibility to repeat any specified operational scenario many times. Radar field-testing with live targets, clutter, weather, noise and deceptive jamming, and other interfering signals allows the creation of a true operational scenario. But actual field test conditions are extremely difficult to control, to describe accurately, as well as to ensure their repeatability to permit accurate statistical validation of radar performance. Also, field-testing is highly costly and time-consuming. Nevertheless, if some resources are available for field-testing it can be considered as an ”excellent tool” to validate radar operational readiness. Far-field testing with simulated targets and interfering signals can provide an excellent scenario repeatability. The main disadvantage of this approach is that it is extremely difficult to create real or near-real scenarios, f.e., to simulate realistic trajectories of moving targets.It is expected [1], that mathematical modelling and computer simulation will become one of the important testing tools in advanced radar performance evaluation. The considerable disadvantage of this is that “the model of radar is evaluated” but not the given real radar in the real-world scenario. In authors’ opinion, computer modelling and simulation is a very powerful tool for radarperformance prediction and for detailed analysis, as a part of the radar design. In particular, computer-modelling techniques will allow very accurate estimations of the radar mission accomplishment probability and time as well as their statistical characteristics by means of statistical simulation of the radar’s operations in any specified scenario. Certainly, this will be achieved, if accurate models of radar and its operational environment (including targets, clutter, jamming, etc.) are available. This approach leads to creating a powerful tool such as radar computer aided design (RCAD).3. Radar Mission Accomplishment TestThe military and very often civil applications for which radar is designed as well as its adaptivity require that its performance should be specified in terms of fitness for mission and must take into account the dynamic nature of such a mission. G eneralized overall system performance parameters that satisfy these requirements may be proposed as the following: "Radar Mission Accomplishment Probability"(RMAP) and "Radar Mission Accomplishment Time" (RMAT). For any particular radar these parameters must adequately be interpreted in terms of its particular mission. For example, if the mission of a weapon locating radar is defined as "to accurately locate the specified number of targets in given combat scenario within the specified time interval",the adjusted definitions can be specialized as follows:Radar mission accomplishment probability is the probability that the specified number of targets is located by given radar with specified accuracy within stated operating area (detection area) during the specified time interval.The radar mission accomplishment time is the average time required by a given radar to locate the specified number of targets with specified accuracy within stated operating area.If the mission of a multifunction radar of an air defense system is “to hit the specified number of enemy targets by means of the radar-guided missiles in given battlefield scenario", the definitions are given by:Radar mission accomplishment probability is the probability that missiles guided by given radar hit the specified number of targets within stated operating area during the specified time interval.The radar mission accomplishment time is the average time required to hit the specified number of targets by missiles guided by a given radar within stated operating area .Obviously, RMAP and RMAT are scenario-dependent. Therefore, a few typical (standardized) scenarios should be used to measure these parameters. This can be justified by the fact that the performance of rival systems or competing versions of the same system can only be compared on equal conditions that should be specified by 3 – 5 standardized scenarios.The flow-chart of a Radar Mission Accomplishment Test Procedure" (RMATP) to measure the RMAP and RMAT is shown in Figure 1. The measurement of traditional parameters is included as a part of this procedure and should be performed if radar fails in the RMATP.Figure 1: Conceptual Block Diagram of RadarPerformance Measurement4. Concept of Super Compact Radar Test Range The essential feature of a real scenario is multiple flat wave fronts across the radar antenna aperture created by moving targets (when radar illuminates them), clutter, and jammers. To simultaneously simulate multiple plane wave fronts an active phased array antenna (APAA) can be used. The APAA should be placed opposite the radar phased array on element-to-element basis (Figure 2).Figure 2: Concept of Opposite APAAThe absorber sheet should be placed across the opposite antenna face to avoid reflections from the "opposite" antenna returning to the radar antenna and producing a large voltage standing wave ratio. The distance between elements should be on the order of magnitude two or three wavelength to ensure that each element is out of the reactive near-field region of the other one.The radar antenna senses the wavefront radiated by the opposite APAA as if it were received from a far-field target at the direction of arrival specified by the electronically steered phase shifters of the APAA.The Super Compact Radar Test Range (SCRTR) concept is based on the opposite APAA. Simplistically,the SCRTR operates in the following manner. Within each pulse repetition interval the radar antenna radiates asignal, which travels to the opposite antenna. The radar signal passes through the opposite antenna to a receiver, is digitized and stored. Then the stored signal is delayed and passes back through the opposite antenna to the radar antenna to be radiated as a plane wave controlled by the opposite antenna's phase shifters.The conceptual block diagram of the SCRTR is shown in Figure 3. This includes the following basic elements: TEES, TSDMC, Documentation and Visualization Units. The key elements needed to simulate multiple wave fronts from moving targets, clutter, and jamming according to the test scenario are the MWFS, TCJS, and WFCP. To evaluate the RMAP and RMAT of the multifunction radar of an air defence system a GMS might be added to the SCRTR's configuration.The TSDMC provides the user interface for programming and controlling the test scenarios, test results reception, processing, storing, and retrieval. TSDMC has to maintain a library of typical scenarios and many other scenarios, which can be used for radar testing.The TEES Controller provides the communications between the TCJS, GMS, WFCP and radar in on-line mode. This controller should be an industrial type computer intended to receive and store the test scenario that is downloaded from the TSDMC. Once a scenario is downloaded from the TSDMC, it is prepared for execution in the TEES under the control of its controller. The TCJS (Figure 4) contains all of the hardware and software, which are necessary to provide simulated target returns to a radar system, clutter, noise and deceptive jamming signals. The TCJS controller is designed to receive, to store and control the part of the test scenario that is supposed to be executed by it. This part may include one or multiple target returns simulation, or clutter or jamming simulation. Since signals, simulated by TCJS, pass to the MWFS and then can be transmitted by means of active phased array as electromagnetic waveswith controlled wave front the target movement can be simulated in range as well as in azimuth and elevation.A part of the scenario consists of a set of trajectories of chosen targets, in which the targets can change their position in range, azimuth and elevation, as well as in velocity, pop-up or disappear.Figure 3: Conceptual Block Diagram of SCRTRFigure 7: Multi-Channel T/R ModuleAdderAmplitude Control From WFCPPhase Shift Control From WFCPFigure 4: TCJ S Conceptual Block DiagramFrom AdditionalFigure 5: Conceptual Block Diagramof Digital ReceiverFigure 6: Conceptual Block Diagram of MWFSOnce this part of the scenario has begun, the TCJS controller constantly calculates the target motion and updates its position and velocity to simulate a moving target. The TCJS controller computes the azimuth and elevation of the target wave front according to the target's position and transfers these angles to the WFCP, which controls the phase shifters of the MWFS channel connected to the given TCJS in order to provide the required direction of arrival.The DR (Figure 5) contains all of the hardware and software, which is necessary to receive and store in digital form the signals, transmitted by radar towards targets, and transfer these signals to the TCJS. The DRSM is based on DRFM that is a high-speed digital circuit, in which a coherent signal can be captured, delayed and replayed without considerable signal distortion.The MWFS (Figure 6) is based on the MCAPA and contains all of the hardware, which is necessary to provide simulation of the flat wave fronts falling on the radar antenna aperture from targets, clutter, and jamming. The key element of the MWFS is a MCTRM (Figure 7). This module contains many channels; each of them consists of a phase shifter and amplifier/attenuator to provide control of simulated flat wave fronts. The outputs of the channels are added and a sum signal goes through the T/R switch to the antenna element.The waveforms transmitted by the radar pass from the antenna element through T/R switch and attenuator to the MWFS adder and then to the DR.The merits and demerits of SCRTR are briefly summarized below.Merits- Indoors, therefore laboratory building assures secrecy- Realistic scenarios simulation, including moving targets, clutter, jamming, and other interfering signals- Possibility to simultaneously simulate multiple wave fronts from independent sources- High accuracy of the radar performance measurement - All weather capability- All kind of performance evaluation (radar mission accomplishment probability and time as well as other “dynamic” and traditional radar performance parameters) - Automatic mode of testing under computer control- Test conditions can accurately be described and controlled- Instantaneous results of testing data processing and documentation- No rotation of RUT and therefore no positioner (heavy duty turn table)- No lofty test towers and long cabling- No mechanical motion of the target/clutter/jamming simulators is necessary.Demerits- Complex, high precision and highly expensive instrumental APAA is required- SCRTR cannot be used as universal radar test range (for general applications and in broad frequency range) since APAA should be built for each particular type of radars to be tested.5. ConclusionThe proposed methodology is based on measuring "radar mission accomplishment probability" and the "radar mission accomplishment time”.These parameters are integrated criteria of the radar’s fitness for mission and take into account the dynamic nature of its mission resulting from a “volatile” operational environment as well as adaptivity of radar.Certainly, the proposed methodology does not and cannot resolve the overall problem of advanced radars procurement, which is a very complex and multicriterion problem. The authors consider the proposed approach to radar performance specification and measurement as a “good initial approximation” to find an objective tool that can make the customer-supplier relationship with regard to the main elements, such as the statement of requirements and the acceptance process, more clear and understandable.The Super Compact Radar Test Range seems to be an appropriate tool, which permits the simulation of realistic radar operating environment and the evaluation of the ability of radar to accomplish its mission.Along with prominent advantages against conventional technologies, the SCRTR has significant disadvantages due to the necessity to use highly expensive active phased array antenna. The authors believe that the progress of antenna technology will considerably mitigate this disadvantage.6. AcknowledgementThe ideas reported in this paper are the result of the authors’ studies on radar testing problems at STX RadarSys Co. The authors gratefully acknowledge the support of Mr. Dong-Hak Chung, Senior Vice President of STX RadarSys Co., Ltd.The Brain Pool Program of the Government of South Korea is sponsoring this work.7. References[1]S. Watts, H.D. Griffiths, J.R Holloway, and et al.: "TheSpecification and Measurement of Radar Performance",International Conference, Radar 2002, Edinburgh,England, 2002.8.GlossaryAPAA: Active Phased Array AntennaDR: Digital ReceiverDRSM: Digital Radar Signal MemoryGMS: Guided Missiles SimulatorMCAPA: Multi-Channel Active Phased Array MCTRM: Multi-Channel Transmit/Receive (T/R) Module MWFS: Multiple Wavefronts SimulatorRCAD: Radar Computer Aided DesignRMAP: Radar Mission Accomplishment Probability RMAT: Radar Mission Accomplishment Time SCRTR: Super Compact Radar Test RangeTCJS: Target/Clutter/Jamming SimulatorTEES: Test Electromagnetic Environment Simulator TSDMC: Test Scenario and Data Management Computer WFCP: Wavefront Control Processor。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

美国国家自然科学基金

AwardTitle Collaborative Research: Investigation of Odor-triggered Neuronal Dynamics and Experience-induced Ol GOALI/Collaborative Research: Deciphering the Mechanisms of Wear to Enable High Performance Tip-Bas EAGER: Multifunctional devices based on coupled phase transitions in antiferromagnetic semiconducto Ultra-precise Coordinate Metrology of Three-dimensional Objects at Micrometer and Nanometer Scales GOALI/Collaborative Research: Deciphering the Mechanisms of Wear to Enable High Performance Tip-Bas GOALI/Collaborative Research: Deciphering the Mechanisms of Wear to Enable High Performance Tip-Bas GOALI/Collaborative Research: Deciphering the Mechanisms of Wear to Enable High Performance Tip-Bas GOALI/Collaborative Research: Deciphering the Mechanisms of Wear to Enable High Performance Tip-Bas

注塑模具英文文献

In particular, for thin parts, the injection molding pressure may become significant and has to be considered in the first phase of manufacturing.
Employing current design approaches for plastic parts will fail to produce the true minimum manufacturing cost in these cases.
Minimizing manufacturing costs for thin injection
molded plastic components
1. Introduction
In most industrial applications, the manufacturing cost of a plastic part is mainly governed by the amount of material used in the molding procend the part deformation after molding [12], analyzing the effects of wall thickness and the flow length of the part [13], and analyzing the internal structure of the plastic part design and filling materials flows of the mold design [14]. Reifschneider [15] has compared three types of mold filling simulation programs, including Part Adviser, Fusion, and Insight, with actual experimental testing. All these approaches have established methods that can save a lot of time and cost. However, they just tackled the design parameters of the plastic part and mold individually during the design stage. In addition, they did not provide the design parameters with minimum manufacturing cost. Studies applying various artificial intelligence methods and techniques have been found that mainly focus on optimization analysis of injection molding parameters [16,17]. For in-stance He et al. [3] introduced a fuzzy- neuro approach for automatic resetting of molding process parameters. By contrast , Helps et al. [18,19] adopted artificial neural networks to predict the setting of molding conditions and plastic part quality control in molding. Clearly, the development of comprehensive molding process models and computer-aided manufacturing provides a basis for realizing molding parameter optimization [3 , 16,17]. Mok et al. [20] propose a hybrid neural network and genetic algorithm approach incorporating Case-Based Reasoning (CBR) to derive initial settings for molding parameters for parts with similar design features quickly and with acceptable accuracy. Mok’s approach was based on past product processing data, and was limited to designs that are similar to previous product data. However, no real R&D effort has been found that considers minimizing manufacturing costs for thin plastic components. Generally, the current practical approach for minimizing the manufacturing cost of plastic components is to minimize the thickness and the dimensions of the part at the product design stage, and then to calculate the costs of the mold design and molding process for the part accordingly, as shown in Fig. 1. The current approach may not be able to obtain the real minimum manufacturing cost when handling thin plastic components. 1.2Manufacturing requirements for a typical thin plastic component As a test example, the typical manufacturing requirements for a thin square plastic part with a center hole, as shown in Fig. 2, are given in Table 1.

学术综合英语_罗立胜 U1

Part A Part B
Pre-listening
Background Information
Listening
New Words and Expressions
plaza, toll station, toll bar or toll gate. This building is usually found on either side of a bridge and at exits. Three systems of toll roads exist: open (with mainline barrier toll plazas); closed (with entry / exit tolls) and all-electronic toll collection (no toll booths, only electronic toll collection gantries at entrances and exits, or at strategic locations on the mainline of the road). Toll roads have been criticized as being inefficient in three ways: 1. They require vehicles to stop or slow down, manual toll collection wastes time and raises vehicle operating costs.
Part A Part B
Pre-listening
Task 1 Listen and Take Notes
Listening
Task 2 Listen for Details

A Retargetable, Ultra-fast Instruction Set Simulator

A Retargetable,Ultra-fast Instruction Set SimulatorJianwen Zhu,Daniel D.GajskiCECS,Information and Computer ScienceUniversity of CaliforniaIrvine,CA92717-3425,USAjzhu,gajski@AbstractIn this paper,we present new techniques which further improve the static compiled instruction set architecture(ISA)simulation by the aggressive utilization of the host machine resources.Such uti-lization is achieved by deﬁning a low level code generation inter-face specialized for ISA simulation,rather than the traditional ap-proaches which use C as a code generation interface.We are able to perform the simulation at a speed up to millions of simu-lated instructions per second(MIPS).This result is onlytimes slower than the native execution on the host machine,the fastest to the best of our knowledge.Furthermore,the code gen-eration interface is organized to implement a RISC like virtual machine,which makes our tool easily retargetable to many host platforms.1IntroductionAn instruction set simulator is a tool that runs on a host ma-chine,typically a workstation,to mimic the behavior of,or sim-ulate a program running on a target machine,which either does not yet exist,or not available.Typically,instruction set simulation allows the user to examine the internal state of the target machine, such as the value of processor registers,during the execution of each instruction.Instruction set simulators are indispensable tools in the devel-opment of conventional computer systems.They help to validate the processor design,the compiler design,as well as evaluate ar-chitectural design decisions such as cache sizes.Instruction set simulators play an even more important role in the development of modern embedded systems,which typically integrate one or more processors,acceleration hardwares,and sometimes analog fron-tends,on one chip to implement one speciﬁc application,such as cellular phone and personal communication systems.Hard-ware/software cosimulation[5],of which instruction set simula-tion is one of the most important parts,must be performed in order to validate and evaluate not only architectural decisions,but also implementation decisions such as how the functionality of the ap-plication is partitioned into hardware and software before any such systems are built.Such capability of virtual prototyping is essen-tial to the success of a product.It is obvious that the most important quality metric of an ISA simulator is its simulation speed,which is especially relevant for the development of high performance systems,where being able to perform simulation in real time is desired.Hardware emulation, despite its cost,has to be used when real time simulation is impos-sible.Other quality metrics include compilation speed,which has to do with how fast simulator can bring an application into a sim-ulatable state;tracability,which has to do with howﬂexible the simulator can collect useful statistics,such as instruction proﬁl-ing;retargetability,which has to do with how easy the tool can be extended to handle new target machines and new host platforms; interoperatability,which has to do with its capability to integrate with other tools,such as debugger,hardware simulator,etc.Due to its importance,numerous ISA simulators have been de-veloped,which can be categorized into three types(Section2), namely,interpretation based,static compilation based and dy-namic compilation based.The tool presented in this paper is a static compilation based simulator.In addition to the advantages inherited,our tool makes several contributions,which lead to its superior performance. First,we propose to use a RISC like virtual machine,which has a predeﬁned instruction set and an unlimited number of virtual reg-isters,to serve as the intermediate to which the target instructions get translated,and from which the host instructions are generated. This is in contrast to the dynamic approaches which usually di-rectly emit host instructions,where retargetability has to be sac-riﬁced;and the traditional static approaches which emit C,where the direct manipulation of host machine resources is impossible.Second,we use an aggressive,yet extremely simple register al-locator,which is tailored for the purpose of ISA simulation.Effec-tively,this allows the direct mapping of target machine registers to host machine registers,while retaining retargetability.Such effect is hard,if not impossible to achieve in the traditional C emitting approach,even when sophisticated optimizations are used.In addition,the low level interface proposed allows us to by-pass the host machine calling conventions,which effectively ex-pose more registers for the register allocator to manipulate on host machine architectures with register windows,such as SPARC.In combination,we have been able to simulate the benchmarks only 1.1-2.5times slower than the execution of their counterparts di-rectly compiled on the host machine,when tracing is off.This result is on average2times faster than the state of the art[4][3][6].The remainder of this paper is organized as follows.Section2 gives more detailed description on the various approaches and compare their trade-offs.Section3presents the detail of our simu-lator.Section4discusses the extensions and limitations.Section5 gives the results on the benchmarks chosen.2Techniques for ISA Simulation2.1Interpretation Based SimulationInterpretation based simulation builds in memory a data struc-ture representing the state of the target processor.It then enters a loop,the body of which executes the sequence of actions:fetch, which reads an instruction word from memory;decode,which an-alyzes the instruction and extracts the opcodeﬁeld of the instruc-tion;dispatch,which use a switch statement to jump to the ap-propriate code to handle a particular instruction;execute,which update the processor state according to the semantics of the in-struction.A representative,widely used interpretative simulator for MIPS processor is described in[2].All most all commercially available simulators are interpretative.Despite ease of implementation and ﬂexibility,interpretive simulators suffer performance problems, mainly due to the tremendous overhead spent on instruction fetch-ing,decoding and dispatching,which,from simulation point of few,is unproductive.The simulator[2]reports a25times slow down of the native execution.[6]reported that it takes DSP sim-ulators provided by vendors6.4hours to simulate G.726speech transcoder for13seconds of speech signals,in contrasts to the7 seconds of native execution time.2.2Compilation Based SimulationCompilation based approaches reduce the runtime overhead by translating each target machine instruction directly to a series of host machine instructions which manipulate the simulated ma-chine state.For example,the MIPS code in Figure1get translated to the SPARC code in Figure2for simulation.Here,sp sim is the memory location which hosts the value of the simulated sp register.addu$sp,$sp,-80Figure1.Target codesethi%hi(sp__sim),%l0ld[%lo(sp__sim)+%l0],%l1add%l1,-80,%l2sethi%hi(sp__sim),%l3st[%lo(sp__sim)+%l3],%l2Figure2.Simulation codeSuch translation can be done either at compile time,as in the case of static compiled simulation,where the overhead is com-pletely eliminated;or at load time,as in the case of dynamic com-piled simulation,where the overhead is amortized over the loops which repeatedly execute the same code.2.3Related WorksStatic compiled simulation usually translates the target pro-gram into C code,and then use an optimizing C compiler(e.g., gcc with option-O3)to translate the C code into host machine instruction.In[6],Such simulators are developed for DSP pro-cessors.The authors reported200-640times speed up than the corresponding interpretative simulator.However,the simulation speed still ranges from0.8MIPS to2.5MIPS,partly due to the fact that bit true simulation of DSP instructions is more complex than RISC instructions.Dynamic compiled simulation translates the target program into host machine code on theﬂy.This approach is pineered by the shade simulator[3],where the SPARC V8,V9and MIPS in-struction set can be simulated at3-10times native time.Inspired by[3],the Embra simulator[4]performs complete machine simu-lation with similar performance.The techniques discussed in this paper are not limited to em-bedded system design.It is also closely related to binary trans-lation,which promises to emulate software of one platform,for example,a windows application,on another platform,for exam-ple,a SUN workstation.3A New Approach for Static Compiled Sim-ulationAs shown in Figure3,our simulator looks like,and in fact is integrated into,a retargetable compiler.The backend(e.g.,MIPS target in Figure3)which emits simulation code for a particular architecture,however,is slightly different from the corresponding cross compilation backend in that for every target instruction to be emitted,it emits a series of virtual machine instructions(Sec-tion3.2)through the simulation code generation interface(Sec-tion3.1)instead.The code generation interface is in turn imple-mented by a host,which translates each virtual machine instruc-tion into a form which can be compiled into host machine instruc-tions.The hosts might manage the host machine registers by the help of a register allocator(Section3.4),which is designed to be machine independent.Figure3.Simulator organizationpublic enum SegKindSEG BSS,SEG LITpublic i n t e r f a c e Hostvoid begin();void end();void exportSymbol(S t r i n g symbol);void importSymbol(S t r i n g name,int s i z e);void segment(SegKind seg);void b e g i n F u n c t i o n(S t r i n g name);void endFunction(S t r i n g name);void e m i t C o n s t a n t V a l u e(Type type,Object value);void em itAddres s Value(S t r i n g name);void e m i t S t r i n g V a l u e(int n,S t r i n g name);void emitSpace(int s i z e);void emitSymbol(S t r i n g name,int s i z e,int a l i g n,int i s s t a t i c);void e m i t I n s t r n(Opcode opcode,Type type,T argetE xpr d e s t,T argetE xpr op1,T argetE xpr op2);int d e c l G l o b a l(S t r i n g name);int d e c l L o c a l();void u n d e c l A l l L o c a l s();Figure4.Simulation code generation inter-face3.1Simulation Code Generation InterfaceFigure4deﬁnes the interface that every host has to im-plement.begin and end gives the host an opportu-nity to initialize andﬁnalize its internal data structure.As their name implies,exportSymbol and importSymbol exports and imports symbols.segment switches the cur-rent segment to either text segment(SEGBSS),or data segment(SEGLIT).beginFunction and endFunction signals the beginning and the end of a func-tion.emitConstantValue,emitAddressValue,and emitString emits compile time values.emitSpace emits uninitialized data.emitSymbol emits either a data symbol or a label.The interface also abstracts the host machine resources by a virtual machine,as deﬁned in Section3.2.The interface functions emitInstrn and declGlobal,declLocal, undeclAllLocals manage the virtual instructions and the vir-tual registers of the virtual machine respectively.The retargetability of our simulator attributes to the fact that the hosts are completely decoupled from the targets thanks to the code generation interface.The host can emit C code(e.g.,C Host in Figure3),an approach equivalent to[6];or directly emit host machine assembly(e.g.,Sparc Host in Figure3).3.2Virtual MachineThe virtual machine that we deﬁne has an instruction set that resembles[8],which in turn is derived from the intermediate rep-resentation of[9].Each instruction is represented as a value tu-ple of opcode,type,destination and operands.The opcodes in-clude arithmetic/logical operations,load/store operations and con-trol transfer operations.The types further constrains the operations to work on a byte(signed or unsigned),halfword,word,long,sin-gle and double precisionﬂoating point,pointer value.They are deﬁned in Figure5.public enum OpcodeOP SUB,OP DIV,OPAND,OP XOR,OP SHR, OP NOT,OP MOV,OPCNVI,OPLD,OPRET,OP JAL,OP BLE,OP BGE,OP BNE,OPC,TYPE S,TYPEI,TYPE L,TYPEF,TYPE P,TYPEi v s p,-80,v s p,where vsp is a vir-tual register.The target calls other interface functions to emit data and other assembly directives.3.4Machine Independent Register AllocatorMost virtual instructions apply certain operations on some source virtual registers and write the result to the destination vir-tual registers.Each virtual register has a memory location in the simulation code to hold its value.For efﬁciency,the virtual regis-ters should be cached in the host machine registers,called the hard registers.The policy towards how the virtual registers are cached comprises the job of the register allocator.3.4.1Greedy AllocationThe straightforward solution is to fetch the source virtual register values from the memory to some scratch registers,compute it,and then stores the result immediately to the memory.An example of such strategy is shown in Figure2.3.4.2Lazy AllocationA better policy is to perform lazy fetching,that is,virtual regis-ter values need not to be loaded from the memory if it is not re-cently written after it is last read from the same basic block;and lazyﬂushing,that is,virtual registers need not to be written to the memory until the end of a basic block.Here,the basic block refers to a piece of code which contains a single entry and does not con-tain control transfer instructions except the last one.On the other hand,in case no hard register is available,spilling has to be per-formed.Essentially,spilling select a virtual register to give up its occupancy of the corresponding hard register,byﬁrstﬂushing its value if it is“dirty”,or,its value is inconsistent with that stored in the memory.3.4.3Fixed AllocationLazy allocation inserts fetching code for theﬁrst use of virtual registers in the basic block,the spilling code whichﬂushes vir-tual register,and an epilogue for every basic block whichﬂushes all the“dirty”virtual registers,for every basic block.These over-heads are needed because the mapping between virtual registers and hard registers are different across different basic blocks.An observation is that if the mapping is consistent across the entire program,then these overhead can be eliminated.This is of course not always feasible since there might not be enough hard registers to hold all the virtual registers.But still,some virtual registers,are so frequently used,such as those which correspond to the stack pointer,program counter,and target scratch registers,that they de-serve to have oneﬁxed hard register allocated whenever possible.3.4.4Hybrid ApproachThis leads to a hybrid approach in which the hard registers are par-titioned into two sets:one is theﬁxed register set,the member of which is assigned to a global virtual register throughout the entire program execution;the other is the temporary register set.This strategy is adopted by our simulator,where a global vir-tual register is assigned aﬁxed hard register on aﬁrst-come-ﬁrst-get basis.Those globals that fail to obtain aﬁxed hard register are mapped to the temporary registers together with the locals accord-ing the the lazy allocation mechanism.Note that our algorithm is of linear complexity.This is in contrast to standard approaches based on liveness analysis and graph coloring,which is(1)an overkill for allocation of locals since their lifetime only last one simulated instruction;(2)un-able to handle globals like ours without expensive interproce-dural analysis and execution proﬁling.Also worthy of men-tion is that although compilers such as gcc provide ways to al-low user to map global variables to a machine register(e.g. by declaring register int sp sim asm(‘‘%g4’’), these methods are unﬂexible and unportable.3.5Host ImplementationA host implements the interface deﬁned by Section3.1.The majority of the work is usually devoted to the implementation of every virtual instruction using host machine instructions,while the management of virtual registers can be delegated to the machine independent register allocator discussed in Section3.4.To use the register allocator,the hard registers as well as how they are partitioned has to be provided.Worthy of mention is that how the virtual instruction is imple-mented sometimes has an inﬂuence on the number of hard registers that can be madeﬁxed.For example,on the SPARC architecture, if the standard calling convention is followed,the register window will be shifted,which make most registers renamed to physically different registers upon every function call,and hence make them illegible to be partitioned into theﬁxed set.In our implementation of the SPARC host,the shifting of register window is suppressed thanks to the low level interface deﬁned.Otherwise if a C emitting approach is followed,only g4through g7is available on SPARC. 4LimitationsThere are limitations for the static compiled approach in gen-eral.Simulators that fall into this category cannot handle self-modifying code,code which load dynamic libraries.Our tool is not immune to these problems.Fortunately,these cases are rare in embedded systems.There are also limitations speciﬁc to our tool.First,our tool works best on high performance host machines with large regis-ter sets.When the host has a limited number of registers,the performance will degrade,however,not to the level worse than those without register allocation.Second,the difference on endi-aness between the target machine and the host machine is ignored. Third,currently the code generation from target machine to virtual machine is directly built on a retargetable compiler,rather than a separate one which accepts assembly or binary as input.While the replacement of additional parsing with direct function call can cer-tainly speed up the compilation,it also ties our tool with a speciﬁc compiler.Fortunately,one can build a“binary translation”version of our tool fairly easily.5ExperimentWe have selected a set of benchmarks to evaluate our simu-lator.COUNTER consists of a loop which simply increments aBenchmark lazy c w/o opt.hybrid tracedCOUNTER9.130 6.045 1.27214IDCT 5.7498.8332 1.5186VITERBI 3.153 4.933 1.2166FIR 6.2499.432 2.9105 LEVISON 2.51059.229 4.164 4.8655 parison of simulation performance of various approachescounter.IDCT is the inverse discrete cosine transform algorithmextracted from JPEG/MPEG.VITERBI is a popular channel cod-ing algorithms.FIR and LEVISON。

叶轮机械非定常流动及气动弹性计算

中图分类号：V211.3 论文编号：1028701 18-B061 学科分类号：080103博士学位论文叶轮机械非定常流动及气动弹性计算研究生姓名周迪学科、专业流体力学研究方向气动弹性力学指导教师陆志良教授南京航空航天大学研究生院航空宇航学院二О一八年十月Nanjing University of Aeronautics and AstronauticsThe Graduate SchoolCollege of Aerospace EngineeringNumerical investigations of unsteady aerodynamics and aeroelasticity ofturbomachinesA Thesis inFluid MechanicsbyZhou DiAdvised byProf. Lu ZhiliangSubmitted in Partial Fulfillmentof the Requirementsfor the Degree ofDoctor of PhilosophyOctober, 2018南京航空航天大学博士学位论文摘要气动弹性问题是影响叶轮机械特别是航空发动机性能和安全的一个重要因素。

作为一个交叉学科，叶轮机械气动弹性力学涉及与叶片变形和振动相关联的定常/非定常流动特性、颤振机理以及各种气弹现象的数学模型等的研究。

本文基于计算流体力学(CFD)技术自主建立了一个适用于叶轮机械定常/非定常流动、静气动弹性和颤振问题的综合计算分析平台，并针对多种气动弹性问题进行了数值模拟研究。

主要研究内容和学术贡献如下：由于叶轮机械气动弹性与内流空气动力特性密切相关，真实模拟其内部流场是研究的重点之一。

基于数值求解旋转坐标系下的雷诺平均N–S(RANS)方程，首先构造了适合于旋转机械流动的CFD模拟方法。

特别的，针对叶片振动引起的非定常流动问题，采用动网格方法进行模拟，通过一种高效的RBF–TFI方法实现网格动态变形；针对动静叶排干扰引起的非定常流动问题，采用一种叶片约化模拟方法，通过一种基于通量形式的交界面参数传递方法实现转静子通道之间流场信息的交换。

仿真模型的时间标准

仿真模型的时间标准English Answer:Time Standards in Simulation Modeling.Time is a crucial aspect of any simulation model, as it governs the progression of events and the overall behaviorof the system being simulated. The choice of time standard, therefore, plays a significant role in the accuracy and efficiency of the model.There are two main types of time standards used in simulation modeling: fixed-time step and variable-time step.Fixed-Time Step.In a fixed-time step simulation, the simulation clock advances at a fixed interval, regardless of the events occurring within the system. This approach is simple to implement and can be computationally efficient. However, itmay lead to inaccuracies if the time step is too large or too small.Variable-Time Step.In a variable-time step simulation, the simulationclock advances based on the occurrence of events. When an event occurs, the clock is updated to the time of the event, and the simulation model advances to the next event. This approach provides greater accuracy than a fixed-time step simulation but can be more computationally expensive.The choice of time standard depends on the specific requirements of the simulation model. For models where events occur at regular intervals, a fixed-time step may be sufficient. For models where events occur at irregular intervals or where the time between events varies significantly, a variable-time step may be necessary.Other Considerations.In addition to the time standard, there are otherfactors to consider when dealing with time in simulation modeling. These factors include:Start Time: The start time of the simulation model may be specified as an absolute time or a relative time.Stop Time: The stop time of the simulation model may be specified as an absolute time or a relative time.Time Units: The time units used in the simulation model must be consistent with the requirements of the system being simulated.中文回答：仿真模型中的时间标准。

2024版SIMATIC[1]

SIMATICcontents•SIMATIC Overview•SIMATIC hardware composition 目录•SIMATIC software features•The Application of SIMATIC inIndustrial Automationcontents•The relationship between SIMATICand digital factories目录•SIMATIC selection andconfiguration suggestions01SIMATIC OverviewDefinition and DevelopmentDefinitionSIMATIC is a family of automation products from Siemens, designed toprovide comprehensive solutions for industrial automation tasksDevelopmentOver the years, SIMATIC has evolved from simple relay based controlsystems to advanced PC based automation solutions, incorporating thelatest technologies in industrial communication, control, and visualizationFeatures and AdvantagesApplication Area02SIMATIC hardware compositionControllerMemoryCPU Stores user programs, data,and system information,ensuring reliable and effectiveoperation of the controllerInterfacesInput/Output ModuleDigital I/O modulesHandle digital signals, convertingthem into a format that can beprocessed by the controllerAnalog I/O modulesConvert analog signals (such asvoltage or current) into digitalvalues that can be used by thecontroller Specialty I/O modules Support specific applications, such as motion control or high speed countingCommunication moduleEthernet modulesProfibus/Profinet modulesOther communication modulesPower modulePower supply units01Redundancy modules02Energy management features0303SIMATIC software featuresProgramming software TIA PortalSTEP 7SIMATIC PCS 7SIMATIC PDMA plant data management software for the collection, processing, and visualizationof plant dataWinCCA Windows based HMI (Human Machine Interface) system for the visualization and monitoring of industrialprocessesSIMATIC NETA communication software for the configuration and monitoring of industrialnetworksMonitoring softwareSIMATIC PDM Diagnostics SIMATIC S7 PLCSIMSIMATIC WinCC OA SIMATIC IT MindSphere04The Application of SIMATIC in Industrial AutomationAutomation of assembly lines Material handling Quality controlProduction line automationProcess control automationProcess monitoring and controladjustment of process variablesData acquisition and analysisidentify potential issuesSafety and complianceRobot control automationRobot programming and controlSIMATIC simplifies robot programming and control, enabling seamlessintegration with other automation componentsPath planning and conflict avoidanceWith SIMATIC, robots can be programmed to effectively plan their paths andavoid conflicts with objects in the workspaceVision systems integrationSIMATIC supports the integration of vision systems, allowing robots toperform complex tasks such as part recognition and inspectionEnergy monitoring and analysis Demand responseand load sheddingRenewable energyintegration010203 Energy management automation05The relationship between SIMATIC and digital factoriesCharacteristicsHigh level of automation and intelligenceReal time data collection and analysisSeamless integration of IT and OT systemsFlexibility and scalability to adapt to changing market demands Emphasis on sustainability and resource efficiencyThe role of SIMATIC in digital factoriesFactoriesTrendsIncreasing options of AI and machine learning for advancedanalytics and process optimizationGrowing use of collaborative robots (cobots) for enhanced humanmachine interactionFactoriesFocus on sustainability and resource efficiency through circular economic approachesFactories Ensuring ManagingDevelopment Trends and Challenges of Digital Factories06SIMATIC selection and configuration suggestionsComprehensive consideration of system requirementsSelection of appropriate modelsTHANKS 感谢观看。

2024杨浦英语二模作文

2024杨浦英语二模作文Here is the English essay on the topic "2024 Yangpu English Simulation Test Essay" with a word count of over 1,000 words:The city of Yangpu is a vibrant and dynamic metropolitan area that has experienced remarkable growth and development in recent years. As a hub for education, innovation, and commerce, Yangpu has become a destination for individuals seeking opportunities to thrive and contribute to the city's ongoing progress. In 2024, the Yangpu English Simulation Test will be a critical milestone for students aspiring to demonstrate their proficiency in the English language and positioning themselves for academic and professional success.The Yangpu English Simulation Test is designed to assess a student's overall competence in the English language, encompassing various aspects such as reading comprehension, writing, listening, and speaking. This comprehensive evaluation serves as a bridge between the academic curriculum and the real-world demands of the global marketplace. By successfully navigating this test, students not only showcase their language skills but also signal their readiness to engage in an increasingly interconnected world.One of the key components of the Yangpu English Simulation Test is the writing assessment. This section challenges students to articulate their thoughts, ideas, and perspectives in a clear and coherent manner. The ability to effectively communicate in written form is a highly valued skill in today's global landscape, as it enables individuals to express themselves, convey complex information, and influence decision-making processes.In the writing assessment, students may be presented with a variety of prompts that require them to demonstrate their critical thinking, analytical skills, and creative expression. These prompts may range from persuasive essays that advocate for a particular stance, to narrative pieces that draw upon personal experiences, to expository writings that explore complex issues and offer well-reasoned solutions.Successful performance on the writing component of the Yangpu English Simulation Test requires a solid foundation in grammar, syntax, and vocabulary. Students must be adept at organizing their ideas, crafting compelling arguments, and employing appropriate rhetorical devices to captivate their audience. Additionally, the ability to write with clarity, concision, and proper mechanics is essential, as it showcases the student's mastery of the English language and their commitment to effective communication.Beyond the writing assessment, the Yangpu English Simulation Test also evaluates a student's proficiency in reading comprehension. This section assesses the student's ability to understand and interpret a variety of written materials, ranging from academic articles and literary works to business documents and media reports. By demonstrating their ability to analyze, synthesize, and draw insightful conclusions from these diverse texts, students showcase their readiness to engage with the complex information and diverse perspectives that permeate the global landscape.The listening component of the test further challenges students to comprehend and respond to spoken English in a variety of contexts. This may involve listening to lectures, presentations, or conversations and then answering questions or summarizing the key points. The ability to actively listen, discern important information, and formulate appropriate responses is a valuable skill in professional and academic settings, where effective communication is essential for collaboration, problem-solving, and decision-making.The speaking assessment of the Yangpu English Simulation Test provides students with the opportunity to demonstrate their fluency, pronunciation, and conversational skills. This section may require students to engage in dialogues, deliver prepared speeches, or respond to spontaneous prompts. By showcasing their ability to articulate their thoughts, engage in discussions, and adapt todifferent communication scenarios, students demonstrate their capacity to navigate the linguistic demands of the global marketplace.Preparing for the Yangpu English Simulation Test requires a comprehensive and multifaceted approach. Students must not only focus on developing their language proficiency but also cultivate critical thinking, problem-solving, and adaptability skills. Effective preparation strategies may include immersing themselves in English-language media, engaging in regular conversational practice, and familiarizing themselves with the test format and assessment criteria.Additionally, students may seek out opportunities to engage with the local and international community, such as participating in language-exchange programs, volunteering in English-speaking environments, or attending conferences and events that foster cross-cultural exchange. By embracing these experiential learning opportunities, students can enhance their cultural awareness, deepen their understanding of diverse perspectives, and further hone their communication skills.The success of the Yangpu English Simulation Test is not only a reflection of the individual student's efforts but also a testament to the collaborative efforts of educators, policymakers, and the broader community. By investing in high-quality English language education,providing access to resources and support, and fostering an environment that values multilingualism and global competence, Yangpu can empower its students to thrive in the increasingly interconnected world.As the 2024 Yangpu English Simulation Test approaches, students across the city will undoubtedly rise to the challenge, driven by their aspirations and the belief that their language proficiency can open doors to a world of opportunities. Through their dedication, resilience, and commitment to excellence, these students will not only demonstrate their mastery of the English language but also contribute to the continued growth and prosperity of Yangpu as a vibrant and globally-minded city.。

carry out a simulation study to

carry out a simulation study toSimulation studies are a valuable tool for understanding complex systems and processes, especially when it's not possible or practical to conduct real-world experiments. A simulation study can help to answer a variety of research questions by replicating the conditions of a real-world scenario in a controlled environment.To carry out a simulation study, you need to follow these general steps:Define the research question: Start by clarifying the purpose of your simulation study. What do you hope to learn by simulating this system or process? Identify the key variables and parameters that will be part of your simulation.Select the appropriate simulation software: There are various simulation software packages available, such as MATLAB, Simulink, or Python-based packages like SimPy or DEAP. Choose one that suits your needs and has the capabilities to handle your specific simulation requirements.Build the simulation model: Based on your research question, construct a mathematical model that represents the system or process you're simulating. This model should capture the essential features and dynamics of the system while abstracting away unnecessary details. Parameterize the model: Specify the values for the variables andparameters in your model. Collect data or make assumptions about these values based on prior knowledge or real-world observations.Run the simulation: Program the simulation using the selected software and execute it to generate results. The software will iteratively update the state of the system according to the defined rules and parameters. Analyze and interpret the results: Examine the data generated by the simulation, looking for patterns, trends, or other insights. Compare these findings with predictions or expectations based on your research question. Validate the results by comparing them with existing literature or real-world data if available.Draw conclusions: Draw conclusions from your analysis, answering your research question and addressing any limitations of your study. Use these insights to inform future research or provide practical guidance for decision-making in related fields.Communicate the findings: Share your results with others through presentations, reports, or academic publications. Provide a clear explanation of your methods, results, and their relevance to the field you're studying.Remember that the quality of your simulation study depends on the validity and realism of your model, as well as the choice of appropriate software and techniques for simulating your system or process.。

方法的英文高级表达

方法的英文高级表达Advanced Expressions for Describing Methods1. Innovative Approach/Methodology:This cutting-edge method employs a unique and groundbreaking approach to tackle the problem at hand.2. Adaptive Strategy:This method is highly flexible and can be adjusted to fit different situations and circumstances.3. Unconventional Technique:This method adopts a non-traditional approach, deviatingfrom conventional methods to achieve superior results.4. Iterative Process:This method emphasizes a continuous and iterative approach, involving repeated cycles of testing and improvements.5. Holistic Approach:6. Rigorous Framework:This method follows a well-structured and rigorous framework, ensuring methodical and meticulous analysis.7. Cross-disciplinary Method:8. Data-driven Methodology:This method relies on extensive data analysis and interpretation to guide decision-making and problem-solving.9. Collaborative Approach:10. Agile Method:This method prioritizes adaptability and responsiveness to changing circumstances, allowing for quick adjustments and improvements.11. Systematic Procedure:This method follows a systematic and step-by-step procedure, ensuring a logical and coherent approach to problem-solving.12. Longitudinal Study:This method involves the collection and analysis of data over an extended period to observe patterns and trends.14. Randomized Control Trial (RCT):This method involves randomly assigning participants to different groups to test the effectiveness of an intervention or treatment.15. Qualitative Research:16. Quantitative Analysis:This method relies on numerical data and statistical techniques to measure and analyze relationships, trends, and patterns.17. Meta-analysis:18. Grounded Theory:This method seeks to generate new theories and concepts from qualitative data, allowing theories to emerge from the data itself.19. Action Research:This method involves implementing and evaluating interventions or changes within a real-world context, aiming to improve practices or solve practical problems.20. Monte Carlo Simulation:21. Genetic Algorithm:This method is an optimization technique inspired by the process of natural selection, using genetic operators to find the best solution among a set of possibilities.22. Neural Network:This method is an artificial intelligence model that attempts to mimic the structure and functioning of the brain, enabling pattern detection and prediction.23. Design Thinking:This method emphasizes empathy, creativity, and iterative problem-solving to create user-centered and innovative solutions.24. Six Sigma:This method is a data-driven approach focused on reducing defects and variability, aiming for near-perfect quality in products or processes.25. Lean Startup:This method advocates for rapid experimentation anditeration in the early stages of a business or project to minimize wasted resources and optimize success.These advanced expressions can help add precision and sophistication when describing methods in various contexts, such as research, problem-solving, and innovation.。