4、外文翻译
4翻译
毕 业 设 计（论 文）外 文 参 考资 料 及 译 文译文题目： CIC MegaCore Function 学生姓名： 高佳 学 号： 1021129024 专 业： 通信工程 所在学院： 龙蟠学院 指导教师： 姜志鹏 职 称： 讲师2013年11月06日CIC MegaCore Function----From DescriptionThis document describes the Altera CIC MegaCore function. The Altera CIC MegaCore function implements a cascaded integrator-comb filter with data ports that are compatible with the Avalon Streaming interface. CIC filters (also known as Hogenauer filters) are computationally efficient for extracting baseband signals from narrow-band sources using decimation, and for constructing narrow-band signals from processed baseband signals using interpolation.CIC filters use only adders and registers, and require no multipliers to handle large rate changes. Therefore, CIC is a suitable and economical filter architecture for hardware implementation, and is widely used in sample rate conversion designs such as digital down converters (DDC) and digital up converters (DUC).The Altera CIC MegaCore function supports the following features:■Support for interpolation and decimation filters with variable rate change factors (2 to 32,000), a configurable number of stages (1 to 12), and two differential delay options (1 or 2).■Single clock domain with selectable number of interfaces and a maximum of 1,024 channels.■Selectable data storage options with an option to use pipelined integrators.■Configurable input data width (1 to 32 bits) and output data width (1 to full resolution data width).■Selectable output rounding modes (truncation, convergent rounding, rounding up, or saturation) and Hogenauer pruning support.■Optimization for speed by specifying the number of pipeline stages used by each integrator.■Compensation filter coefficients generation.■Easy-to-use MegaWizard interface for parameterization and hardware generation.■IP functional simulation models for use in Altera-supported VHDL and Verilog HDL simulators.■DSP Builder ready.Cascaded Integrator Comb (CIC) filters are widely used in modern communication systems. As the signal processing in all aspects of requirements are constantly improve, in digital technology, the design of the filter appears increasingly important.Those who have signal processing ability of device can be referred to as a filter.In the modern telecommunications equipment and all kinds of control system, filter is widely used.Of all the electronic devices, using the most, the most widely used, technology is the most complex filter.Filter quality directly decides the product quality, good performance of filter can make the system more stable, so the filter of the countries all over the research and production has always been highly valued.With the wide application of digital technology, field programmable gate array (FPGA) has been the rapid development, integration and speed is growing.FPGA has high integration and reliability of the gate array (FPGA), and programmable resistance, maximum limit reduces the design cost, shorten the development cycle.Using CIC filters provides a silicon efficient architecture for performing sample rate conversion. This is achieved by extracting baseband signals from narrow-band sources using decimation, and constructing narrow-band signals from processed baseband signals using interpolation. The key advantage of CIC filters is that they use only adders and registers,and do not require multipliers to implement in hardware for handling large rate changes.A CIC filter (also known as a Hogenauer filter) can be used to perform either decimation or interpolation. A decimation CIC filter comprises a cascade of integrators (called the integrator section), followed by a down sampling block (decimator) and a cascade of differentiators (called the differentiator or comb section). Similarly an interpolation CIC filter comprises a cascade of differentiators, followed by an up sampling block (interpolator) and a cascade of integrators .In a CIC filter, both the integrator and comb sections have the same number of integrators and differentiators. Each pairing of integrator and differentiator is called a stage. The number of stages ( N ) has a direct effect on the frequency response of a CIC filter. The response of the filter is determined by configuring the number of stages N , therate change factor R and the number of delays in the differentiators (called the differential delay) M . In practice, the differential delay is set to 1 or 2.The MegaWizard interface only allows you to select legal combinations of parameters, and warns you of any invalid configurations .For high rate change factors, the maximum required data width for no data loss is large for many practical cases. To reduce the output data width to the input level, quantization is normally applied at the end of the output stage. In this case, the following rounding or saturation options are available:■Truncation : The LSBs are dropped. (This is equivalent to rounding to minus infinity.)■Convergent rounding . Also known as unbiased rounding . Rounds to the nearest even number . If the most significant deleted bit is one, and either the least significant of the remaining bits or at least one of the other deleted bits is one, then one is added to the remaining bits.■Round up: Also known as rounding to plus infinity. Adds the MSB of the discarded bits for positive and negative numbers via the carry in.■Saturation: Puts a limit value (upper limit in the case of overflow, or lower limit in the case of negative overflow) at the output when the input exceeds the allowed range. The upper limit is+2n-1 and lower limit is –2n.These rounding options can only be applied to the output st age of the filter. The data widths at the intermediate stages are not changed. The next section describes cases where the data width at the intermediate stages can be changed.Hogenauer pruning [Reference ] is a technique that utilizes truncation or rounding in intermediate stages with the retained numb er of bits decreasing monotonically from stage to stage, while the total error introduced is still no greater than the quantization error introduced by rounding the full precision output. This technique helps to reduce the number of logic cells used by the filter and gives better performance.The existing algorithms for computing the Hogenauer bit width growth for large N and R values are computationally expensive.For more information about these algorithms, refer to U. Meyer-Baese, Digital Signal Processing with Field Programmable Gate Arrays, 2nd Edition, Spinger, 2004.The CIC MegaCore function has pre-calculated Hogenauer pruning bit widths stored within the MegaCore function. There is no need to wait for Hogenauer pruning bit widths to be calculated if Hogenauer pruning is enabled for a decimation filter. Hogenauer pruning is only available to decimation filters when the selected output data width is smaller than the full output resolution data width.There are often many channels of data in a digital signal processing (DSP) system that require filtering by CIC filters with the same configuration. These can be combined into one filter, which shares the adders that exist in each stage and reduces the overall resource utilization. This combined filter uses fewer resources than using many individual CIC filters. For example, a two-channel parallel filter requires two clock cycles to calculate two outputs. The resulting hardware would need to run at twice the data rate of an individual filter. This is especially useful for higher rate changes where adders grow particularly large.To minimize the number of logic elements , a multiple input single output (MISO) architecture can be used for decimation filters, and a single input multiple output (SIMO) architecture for interpolation filters as described in the following sections.In many practical designs, channel signals come from different input interfaces. On each input interface, the same parameters including rate change factors are applied to the channel data that the CIC filter is going to process. The CIC MegaCore function allows the flexibility to exploit time sharing of the low rate differentiator sections. This is achieved by providing multiple input interfaces and processing chains for the high rate portions, then combining all of the processing associated with the lower rate portions into a single processing chain. This strategy can lead to full utilization of the resources and represents the most efficient hardware implementation. These architectures are known as multiple input single output (MISO) decimation filters.Single input multiple output (SIMO) is a feature associated with interpolation CIC filters. In this architecture, all the channel signals presented for filtering come from a single input interface.Like the MISO case, it is possible to share the low sampling rate differentiator section amongst more channels than the higher sampling frequency integrator sections. Therefore, this architecture features a single instance of the differentiator section, and multiple parallel instances of the integrator sections.After processing by the differentiator section, the channel signals are split into multiple parallel sections for processing in a high sampling frequency by the integrator sections. The sampling frequency of the input data is such that it is only possible to time multiplex two channels per bus, therefore the CIC filter must be configured with two input interfaces. Because two interfaces are required, the rate change factor must also be at least two to exploit this architecture. Up to 1,024 channels can be supported by using multiple input interfaces in this way.Single input multiple output (SIMO) is a feature associated with interpolation CIC filters. In this architecture, all the channel signals presented for filtering come from a single input interface. Like the MISO case, it is possible to share the low sampling rate differentiator section amongst more channels than the higher sampling frequency integrator sections.Therefore, this architecture features a single instance of the differentiator section, and multiple parallel instances of the integrator sections.After processing by the differentiator section, the channel signals are split into multiple parallel sections for processing in a high sampling frequency by the integrator sections.The required sampling frequency of the output data is such that it is only possible to time multiplex two channels per bus. Therefore the CIC filter must be configured with four output interfaces. Because four interfaces are required, the rate change factor must also be at least four to exploit this architecture, but in this example a rate change of eight is illustrated.SIMO architecture is applied when an interpolation filter type is chosen and the number of interfaces selected in the MegaWizard interface is greater than one.The total number of input channels must be a multiple of the number of interfaces. To satisfy this requirement, you may need to either insert dummy channels or use more than one CIC MegaCore function. Data is transferred as packets using AvalonStreaming interfaces. CIC filters have a low-pass filter characteristic. There are only three parameters (the rate change factor R , the number of stages N , and the differential delay M ) that can be modified to alter the passband characteristics and aliasing/imaging rejection. However, due to their drooping passband gains and wide transition regions, CIC filters alone cannot provide the flat passband and narrow transition region filter performance that is typically required in decimation or interpolation filtering applications.This problem can be alleviated by connecting the decimation or interpolation CIC filter to a compensation FIR filter which narrows the output bandwidth and flattens the passband gain.You can use a frequency sampling method to determine the coefficients of a FIR filter that equalizes the undesirable passband droop of the CIC and construct an ideal frequency response.The ideal frequency response is determined by sampling the normalized magnitude response of the CIC filter before inverting the response.Generally, it is only necessary to equalize the response in the passband, but you can sample further than the passband to fine tune the cascaded response of the filter chain.The Avalon-ST interface can also support more complex protocols for burst and packet transfers with packets interleaved across multiple channels.The Avalon-ST interface inherently synchronizes multi-channel designs, which allows you to achieve efficient, time-multiplexed implementations without having to implement complex control logic.CIC MegaCore函数----摘自 描述这篇文章对Altera公司的CIC 宏函数作了说明。
(完整版)外文翻译
外文文献原稿和译文原稿logistics distribution center location factors:(1) the goods distribution and quantity. This is the distribution center and distribution of the object, such as goods source and the future of distribution, history and current and future forecast and development, etc. Distribution center should as far as possible and producer form in the area and distribution short optimization. The quantity of goods is along with the growth of the size distribution and constant growth. Goods higher growth rate, the more demand distribution center location is reasonable and reducing conveying process unnecessary waste.(2) transportation conditions. The location of logistics distribution center should be close to the transportation hub, and to form the logistics distribution center in the process of a proper nodes. In the conditional, distribution center should be as close to the railway station, port and highway.(3) land conditions. Logistics distribution center covers an area of land in increasingly expensive problem today is more and more important. Is the use of the existing land or land again? Land price? Whether to conform to the requirements of the plan for the government, and so on, in the construction distribution center have considered.(4) commodities flow. Enterprise production of consumer goods as the population shift and change, should according to enterprise's better distribution system positioning. Meanwhile, industrial products market will transfer change, in order to determine the raw materials and semi-finished products of commodities such as change of flow in the location of logistics distribution center should be considered when the flow of the specific conditions of the relevant goods.(5) other factors. Such as labor, transportation and service convenience degree, investment restrictions, etc.How to reduce logistics cost，enhance the adaptive capacity and strain capacity of distribution center is a key research question of agricultural product logistics distribution center．At present，most of the research on logistics cost concentrates off theoretical analysis of direct factors of logistics cost, and solves the problem of over-high logistics Cost mainly by direct channel solution．This research stresses on the view of how to loeate distribution center, analyzes the influence of locating distribution center on logistics cost．and finds one kind of simple and easy location method by carrying on the location analysis of distribution center through computer modeling and the application of Exeel．So the location of agricultural product logistics distribution center can be achieved scientifically and reasonably, which will attain the goal of reducing logistics cost, and have a decision．making support function to the logisties facilities and planning of agricultural product．The agricultural product logistics distribution center deals with dozens and even hundreds of clients every day, and transactions are made in high-frequency. If the distribution center is far away from other distribution points，the moving and transporting of materials and the collecting of operational data is inconvenient and costly. costly．The modernization of agricultural product logistics s distribution center is a complex engineering system，not only involves logistics technology, information technology, but also logistics management ideas and its methods，in particular the specifying of strategic location and business model is essential for the constructing of distribution center. How to reduce logistics cost，enhance the adaptive capacity and strain capacity of distribution center is a key research question of agricultural product logistics distribution center. The so—called logistics costs refers to the expenditure summation of manpower, material and financial resources in the moving process of the goods．such as loading and unloading，conveying，transport，storage，circulating，processing, information processing and other segments. In a word。
4字祝福语外文翻译
4字祝福语外文翻译Blessing is a universal language that transcends borders and connects people from different cultures and backgrounds. Whether it's a simple "good luck" or a heartfelt "may all your dreams come true," the power of a four-word blessing can bring warmth and joy to anyone who receives it.In Chinese culture, four-word blessings are often used to convey well-wishes and good intentions. These concise and meaningful phrases are believed to carry positive energy and bring blessings to the recipient. From "平安幸福" (peace and happiness) to "事业有成" (success in career), these four-word blessings encompass a wide range of wishes for health, prosperity, and happiness.When it comes to translating these four-word blessings into foreign languages, it's important to capture not only the literal meaning but also the cultural and emotional nuances behind the words. Each language has its own unique expressions and idioms that convey similar sentiments, and finding the right words to convey the essence of a blessing is crucial in ensuring that the message resonates with the recipient.In English, four-word blessings can take on various forms, from simple and straightforward phrases like "love and happiness" to more poetic expressions such as "joyful heart, peaceful mind." The key is to convey the sincerity and warmth behind the blessing, regardless of the specific words used.In Spanish, four-word blessings often reflect the rich cultural traditions and values of the language. Phrases like "amor y paz" (love and peace) and "salud y prosperidad" (health and prosperity) encapsulate the deeply rooted beliefs in family, love, and well-being.In French, the elegance and beauty of the language are reflected in four-word blessings such as "joie et bonheur" (joy and happiness) and "paix et amour" (peace and love). These phrases evoke a sense of romance and sophistication, adding an extra layer of charm to the blessings.In Japanese, the art of expressing blessings is deeply ingrained in the language and culture. Four-word blessings like "健康と幸せ" (health and happiness) and "平和と愛" (peace and love) reflect the Japanese values of harmony, gratitude, and mindfulness.No matter the language, the essence of a four-word blessing remains the same – to convey heartfelt wishes for the well-being and happiness of the recipient. Whether it's in Chinese, English, Spanish, French, Japanese, or any other language, the power of a sincere blessing knows no bounds.In a world where communication knows no borders, the ability to convey blessingsin different languages is a testament to the universal desire for love, happiness, and peace. As we continue to connect with people from diverse backgrounds and cultures, the exchange of blessings in various languages serves as a reminder of our shared humanity and the beauty of diversity.In conclusion, the translation of four-word blessings into foreign languages is not simply a matter of finding equivalent words, but rather a delicate art of capturing the essence and spirit of the blessings across different cultures and languages. It is a celebration of the universal language of love, kindness, and goodwill that unites us all, regardless of where we come from or what language we speak. So, whether it's "平安幸福," "love and happiness," or "paix et amour," may the blessings we share bring warmth and joy to all who receive them.。
企业固定资产管理外文文献翻译最新
企业固定资产管理外文文献翻译最新4 System designunderstand its usage.Employees to access enterprise fi某ed assets management system management module to the staff is divided into threebroad categories: system administrators assist and consult the information personnel; According to different user's identity, they see the application interface is different also, so that we can make different users access to the application of different functions. After the user login page is to authenticate. Only by verifying employees can login system into the corresponding page. Staff management module is mainly to achieve the management of users and administrators at all levels. Contained in the user information management features: change user information and query the user information and the administrator management is including ads or modify the administrator information and query the administrator to join the new user. Ordinary users can onlyto query and fi某ed assets of the fi某ed assets of the state-owned enterprises collect module for the corresponding operation, for the higher authority of user information module and management module for fi某ed assets, only the administrator can operate.文献出处: Daum J H. The study on fi某ed assets management of enterprise [J]. Measuring business e某cellence, 2023, 2(1): 6-17. 译文摘要计算机技术的飞速发展，使计算机技术已经渗透到了各行各业，它早已成为各行业不可或缺的一部分。
21世纪大学英语翻译
21世纪大学英语翻译Unit 1一、汉译英1)你知道约翰这次失败的原因吗？他在中学里几乎全优。
(lead to, failure, excel in)Do you know what has led to John’s failure this time? He excelled in almost everything in high school.2)不要把今天应该做的的事情推迟到明天。
如果你落后就很难赶上了。
(put off, what, fall behind, catch up)Don’t put off till tomorrow what you should do today. If you fall behind, it will be difficult for you to catch up.3) 他总是用新方法来解决问题，所以他在工作中取得了很大的成功。
(achieve, success, attack) He achieves great success in his work because he always finds new ways to attack problems.4)不要对这个孩子太严格。
你应该让他有些玩耍的时间来减轻压力。
(be hard on, allow, fun time, reduce, stress)Don’t be too hard on the child. You should allow him to have some fun time to reduce stress.5) 我们都期待史密斯教授给我们的大学学习一些有益的指导。
(expect, helpful tips)We all expect Prof. Smith to give us some helpful tips on college study.6) 贝蒂面带紧张的神色，好像害怕向别人做自我介绍似的。
外文翻译原文
Stability of hybrid system limit cycles: application to the compass gait biped RobotIan A. Hiskens'Department of Electrical and Computer EngineeringUniversity of Illinois at Urbana-ChampaignUrbana IL 61801 USAAbstractLimit cycles are common in hybrid systems. However the non-smooth dynamics of such systems makes stability analysis difficult. This paper uses recent extensions of trajectory sensitivity analysis to obtain the characteristic multipliers of non-smooth limit cycles. The stability of a limit cycle is determined by its characteristic multipliers. The concepts are illustrated using a compass gait biped robot example.1 IntroductionHybrid system are characterized by interactions between continuous (smooth) dynamics and discrete events. Such systems are common across a diverse range of application areas. Examples include power systems [l], robotics [2, 3], manufacturing [4] and air-traffic control [5]. In fact, any system where saturation limits are routinely encountered can be thought of as a hybrid system. The limits introduce discrete events which (often) have a significant influence on overall behaviour.Many hybrid systems exhibit periodic behaviour. Discrete events, such as saturation limits, can act to trap the evolving system state within a constrained region of state space. Therefore even when the underlying continuous dynamics are unstable, discrete events may induce a stable limit set. Limit cycles (periodic behaviour) are often created in this way. Other systems, such as robot motion, are naturally periodic.Limit cycles can be stable (attracting), unstable (repelling) or non-stable (saddle). The stability of periodic behaviour is determined by characteristic (or Floquet) multipliers. A periodic solution corresponds to a fixed point of a Poincare map. Stability of the periodic solution is equivalent to stability of the fixed point. The characteristic multipliers are the eigenvalues of the Poincare map linearized about the fixed point. Section 4 reviews the connection between this linearized map and trajectory sensitivities.Poincare maps have been used to analyse the stability of limit cycles in various forms of hybrid systems. However calculation of the underlying trajectory sensitivities has relied upon particular system structures, see for example [7, 8], or numerical differencing, for example [6]. This paper uses a recent generalization of trajectory sensitivity analysis [9] to efficiently detemine the stability of limit cycles in hybrid systems.A hybrid system model is given in Section 2. Section 3 develops the associated variational equations. This is followed in Section 4 by a review of stability analysis of limit cycles. Conclusions and extensions are presented in Section 5.2 ModelDeterministic hybrid systems can be represented by a model that is adapted from a differential-algebraic (DAE) structure. Events are incorporated via impulsive action and switching of algebraic equations, giving the Impulsive Switched (DAIS) modelwheren x R ∈ are dynamic states and my R ∈ are algebraic states;(.)δ is the Dirac delta;(.)u is the unit-step function;,:n mnj f h RR +→；(0)(),:i n mng gR R ±+→; some elements of each(.)gwill usually be identicallyzero, but no elements of the composite g should be identically zero; the()i g± aredefined with the same form as g in (2), resulting in a recursive structure for g;,dey yare selected elements of y that trigger algebraic switching and state reset(impulsive) events respectively;dyandeymay share common elements.The impulse and unit-step terms of the DAIS model can be expressed in alternative forms:Each impulse term of the summation in (1) can be expressed in the state reset formwhere the notation x+denotes the value of x just after the reset event, whilstx-andy-refer to the values of x and y just prior to the event.The contribution of each()i g± in (2) can be expressed aswith (2) becomingThis form is often more intuitive than (2).It can be convenient to establish the partitionswherex -are the continuous dynamic states, for example generator angles, velocities andfluxes;z are discrete dynamic states, such as transformer tap positions and protection relay logic states;λ are parameters such as generator reactances, controller gains and switching times. The partitioning of the differential equations f ensures that away from events,x -evolves according to .(,)x y f x --=, whilst z and λ remain constant. Similarly,the partitioning of the reset equationsjhensures thatx -and λ remain constantat reset events, but the dynamic states z are reset to new values given by(,)jh y x z--+=-. The model can capture complex behaviour, from hysteresis and non-windup limits through to rule-based systems [l]. A more extensive presentation of this model is given in [9].Away from events, system dynamics evolve smoothly according to the familiardifferential-algebraic modelwhere g is composed of(0)gtogether with appropriate choices of()i g- or()i g+ ,depending on the signs of the corresponding elements of yd. At switching events (2),some component equations of g change. To satisfy the new g = 0 equation, algebraic variables y may undergo a step change. Reset events (3) force a discrete change in elements of x. Algebraic variables may also step at a reset event to ensure g= 0 is satisfied with the altered values of x. The flows of and y are defined respectively aswhere x(t) and y(t) satisfy (l),(2), along with initial conditions,3 'Ikajectory SensitivitiesSensitivity of the flowsxφandyφto initial conditionsxare obtained bylinearizing (8),(9) about the nominal trajectory,The time-varying partial derivative matrices given in (12),(13) are known as trajectory sensitiuities, and can be expressed in the alternative formsThe formxx ,xy provides clearer insights into the development of thevariational equations describing the evolution of the sensitivities. The alternative form 0(,)x t x φ, 0(,)yt x φ highlights the connection between the sensitivities and the associated flows. It is shown in Section 4 that these sensitivities underlie the linearization of the Poincare map, and so play a major role in determining the stability of periodic solutions.Away from events, where system dynamics evolve smoothly, trajectory sensitivities 0xx andxy are obtained by differentiating (6),(7) withrespect to 0x.This giveswhere/xf x f≡∂∂, and likewise for the other Jacobian matrices. Note that,,,xyxyf fg gare evaluated along the trajectory, and hence are time varyingmatrices. It is shown in 19, 101 that the numerical solution of this(potentially high order) DAE system can be obtained as a by-product of numerically integrating the original DAE system (6),(7). The extra computational cost is minimal. Initial conditions forxx are obtained from (10) aswhere I is the identity matrix. Initial conditions for 0zy follow directly from(17),Equations (16),(17) describe the evolution of the sensitivitiesxx andxybetween events. However at an event, the sensitivities are generally discontinuous. It is necessary to calculate jump conditions describing the step change inxx andxy . For clarity, consider a single switching/reset event, so the model (1),(2) reduces(effectively) to the formLet （(),()x y ττ） be the point where the trajectory encounters the triggering hypersurface s(x,y) = 0, i.e., the point where an event is initiated. This point is called the junction point and r is the junction time. It is assumed the encounter is transversal.Just prior to event triggering, at time τ-, we haveSimilarly,,y x++are defined for time τ+, just after the event has occurred. It isshown in [9] that the jump conditions for the sensitivitiesxx are given byThe assumption that the trajectory and triggering hypersurface meet transversally ensures a non-zero denominator for 0x τ The sensitivitiesxy . immediatelyafter the event are given byFollowing the event, i.e., for t τ+>, calculation of the sensitivities proceeds according to (16),(17) until the next event is encountered. The jump conditions provide the initial conditions for the post-event calculations.4 Limit Cycle AnalysisStability of limit cycles can be determined using Poincare maps [11, 12]. This section provides a brief review of these concepts, and establishes the connection with trajectory sensitivities.A Poincark map effectively samples the flow of a periodic system once every period. The concept is illustrated in Figure 1. If the limit cycle is stable, oscillations approach the limit cycle over time. The samples provided by the corresponding Poincare map approach a fixed point. A non-stable limit cycle results in divergent oscillations. For such a case the samples of the Poincare map diverge.To define a Poincare map, consider the limit cycle Γshown in Figure 1. Let ∑ be a hyperplane transversal to Γ at*x. The trajectory emanating from*xwill again encounter ∑ at*xafter T seconds, where T is the minimum period of the limit cycle. Due to the continuity of the flowxφwith respect to initial conditions, trajectories starting on ∑ in a neighbourhood of*x. will, in approximately T seconds, intersect ∑ in the vicinity of*x. Hencexφand ∑define a mappingwhere()kT x ττ≈ is the time taken for the trajectory to return to ∑. Complete details can hefound in [11,12]. Stability of the Paincare map (22) is determined by linearizing P at the fixed point*x, i.e.,From the definition of P(z) given by (22), it follows that DP(*x) is closely related to thetrajectory sensitivities***(,)(,)xxT T x x xφφ∂≡∂. In fact, it is shown in [11] thatwhereσ is a vector normal to ∑.The matrix*(,)xT x φis exactly the trajectory sensitivity matrix after one period of the limitcycle, i.e., starting from*xand returning to*x. This matrix is called the Monodromymatrix .It is shown in [11] that for an autonomous system, one eigenvalue of *(,)xT x φ isalways 1, and the corresponding eigenvector lies along **(,)f y x The remaining eigenvalues*(,)xT x φof coincide with the eigenvalues of DP(*x ), and are known as the characteristicmultipliers mi of the periodic solution. The characteristic multipliers are independent of the choice of cross-section ∑ . Therefore, for hybrid systems, it is often convenient to choose ∑ as a triggering hypersurface corresponding to a switching or reset event that occurs along the periodic solution.Because the characteristic multipliers mi are the eigenvalues of the linear map DP(x*), they determine the stability of the Poincarb map P(kx), and hence the stability of the periodic solution.Three cases are of importance: 1. Alli m lie within the unit circle, i.e., 1im<,i ∀.The map is stable, so the periodicsolution is stable. 2. Allim lie outside the unit circle. The periodic solution is unstable.3. Someim lie outside the unit circle. The periodic solution is non-stable.Interestingly, there exists a particular cross-section*∑, such thatwhere *ς∈∑.This cross-section*∑is the hyperplane spanned by the n - 1 eigenvectors of*(,)xT x φthat are not aligned with **(,)f y x . Therefore the vector *σthat is normal to*∑ is the left eigenvector of *(,)xT x φ corresponding to the eigenvalue 1. The hyperplane*∑is invariant under*(,)xT x φ, i.e., **(,)f y x maps vectors *ς∈∑back into*∑.5 ConclusionsHybrid systems frequently exhibit periodic behaviour. However the non-smooth nature of such systems complicates stability analysis. Those complications have been addressed in this paper throughapplication of a generalization of trajectory sensitivity analysis. Deterministic hybrid systems can be represented by a set ofdifferential-algebraic equations, modified to incorporate impulse (state reset) action and constraint switching. The associated variational equations establish jump conditions that describe the evolution of sensitivities through events. These equations provide insights into expansion/contraction effects at events. This is a focus of future research.Standard Poincar6 map results extend naturally to hybrid systems. The Monodromy matrix is obtained by evaluating trajectory sensitivities over one period of the (possibly non-smooth) cyclical behaviour. One eigenvalue of this matrix is always unity. The remaining eigenvalues are the characteristic multipliers of the periodic solution. Stability is ensured if all multipliers lieReferences[l] LA. Hiskens and M.A. Pai, “Hybrid systems view of power system modelling,” in Proceedings of the IEEE International Symposium on Circuits and Systems, Geneva, Switzerland, May 2000.[2] M.H. Raibert, Legged Robots That Balance, MIT Press, Cambridge, MA, 1986.[3] A. Goswami, B. Thuilot, and B. Espiau, “A study of the passive gait of a compass-like biped ro bot: symmetry and chaos,’’ International Journal of Robotics Research, vol. 17, no. 15, 1998.[4] S. Pettersson, “Analysis and design of hybrid systems,” Ph.D. Thesis, Department of Signals and Systems, Chalmers University of Technology, Goteborg, Sweden, 1999.[5] C. Tomlin, G. Pappas, and S. Sastry, “Conflict resolution for air traffic management:A study in multiagent hybrid systems,” IEEE Transactions on Automatic Control, vol. 43, no. 4, pp. 509-521, April 1998.[6] A. Goswami, B. Espiau, and A. Keramane, “Limit cycles in a passive compass gait biped and passivity-mimicking contr ol laws,” Journal of Au tonomous Robots, vol. 4, no. 3, 1997. 171 B.K.H. Wong, H.S.H. Chung, and S.T.S. Lee, ‘Computation of the cycle state-variable sensitivity matrix of PWM DC/DC converters and its applica tion,” IEEE Transactions on Circuit s and Systems I, vol. 47, no. 10, pp. 1542-1548, October 2000.[8] M. Rubensson, B. Lennartsson, and S. Petters son, “Convergence to limit cycles in hybrid systems - an example,” in Prepri nts of 8th International Federation of Automatic Control Symposium on Large Scale Systems: Theo y d Applications, Rio Patras, Greece, 1998, pp. 704-709.[9] I.A. Hiskens and M.A. Pai, “Trajectory sensitivity analysis of hyhrid systems,” IEEE Transactions on Circuits and Systems I, vol. 47, no. 2, pp. 204-220, February 2000.[10]D. Chaniotis, M.A. Pai, and LA. Hiskens, “Sen sitivity analysis of differential-algebraic systems using the GMRES method - Ap plication to power systems,” in Proceedings of the IEEE International Symposium on Circuits and Systems, Sydney, Australia, May 2001.[11]T.S Parker and L.O. Chua, Practical Numerical Algorithms for Chaotic Systems, Springer-Verlag, New York, NY, 1989.[12]R. Seydel, Practical Bifurcation and Stability Analysis, Springer-Verlag. New York, 2nd edition, 1994.。
物流配送外文文献及翻译
1、 INTRODUCTIONLogistics is normally considered as nothing more than getting the right product to theright place at the right time for the least cost、 Faced with a rapidly changing environment, revolutionary changes in technology, continued government deregulation, the shortening of product life cycle, proliferation of product lines and shifts in traditional manufacturer-retailer relationships, many organisations have had to rethink their traditional assumptions、Over the last ten years one of the most significant changes in management thinking wasthe emphasis on the search for strategies that will provide superior value in competition、Logistics management has the potential to assist the organisation in the achievement of botha cost/productivity advantage and a value advantage、 The importance of logistics and its integration in the supply chain was argued by、China is a huge consumer market that accounted for a third of global economic growthover the past three years、 Its development speed and potential cannot be ignored by the restof the world、 As a result of China’s internal and external economic attributes, most of the、 In particular in the automobileglobal consumer brands have established operations thereindustry, many of the leading global OEMs including Honda, Toyota, General Motors, Volkswagen and Ford have established joint-venture partnerships with local car manufacturers、 Auto sales in China rose by 76% in the year to July 2003 and by 2011,、 InChina is expected to surpass Japan to become the wor ld’s second largest auto marketorder to compete in the Chinese market share and satisfy increasing demand, these operations are continuously expanding their production volumes with astonishing speed、Such expansion is, however carried out in the context of a legacy environment、China spans a large geographical area with, in many parts, under-developed infrastructure、 This presents a challenge to efficient deployment of logistics strategies、Furthermore, the involvement of third party logistics providers, favoured by most globalOEMs, is an emergent consideration in China、 Finally, the conflicts that inevitably arise inthe joint venture partnerships lead to delays in the introduction of western logistics management e xperiences and methods from the OEMs、All these factors increase the、difficulties in managing logistics by China’s local auto makers2、 The overall development of foreign distribution Overview2、1 The United States of modern logistics developmentTwenty-first century from the 60s on wards, the rationalization of distribution of goodsin general are valued in the United States to take the following measures: First, the warehouse will replace the old distribution center: The second is the management of the introduction of computer networks, on the loading and unloading, handling, custody, standardized operation, improve operating efficiency; Third, the common chain distribution centers set up to promote the growth of chain-effective、 United States chain stores have a variety of distribution centers, mainly in the wholesale-based, r etail and warehouse-type three types、2、2 Japan's modern logistics developmentOn logistics and distribution of wood with the following features: well-developed distribution channels, frequent, low-volume stock, logistics and distribution reflects the common and set the trend sticks, logistics and distribution cooperative, the Government planning in the development of modern logistics and distribution play an important role inthe process of 、2、3 European modern development of logisticsCountries in Europe, especially Germany, logistics refers to the user's orders in accordance with the requirements of positions in the logistics sub-goods distribution, the goods will be sent to the consignee with good activities、Germany's logistics industry formed of basic commodities from origin to distribution center, from the distribution center (and sometimes through more than one distribution center) arrive at the modern mode of end customers、 Traveled in Germany, it can be said of the logistics and distribution in Germany has been formed to final demand-oriented to the modernization of transport and high-techinformation network as a bridge to a reasonable R69 distribution center hub to run a complete system、2、4 the main reasons of logistics industry developing faster in developed countriesRelying on high-tech to the core economies of scale to allow flexibility based on a variety of forms、3、China's 3PL enterprises are facing a major obstacle to business3、1 The current situation of China's 3PLChina's 3PL enterprises: service radius of a small, low entry barriers、 With the gradual warming heat logistics, urban logistics industry is also increasingly unitary covered by the importance and development、However, due to historical reasons in our country, the long-standing emphasis on production of a light flow, heavy flow to light the idea of the logistics, distribution of development in the not yet ripe at this stage, there is the issue more prominent in the following two aspects: the service delivery difficult to play a central role,the process of distribution of the low level of modernization、China's 3PL companies with foreign 3PL companies mainly in the gap between the three aspects: First, procurement capacity, and the other is logistics, and the third is cash flow、Aspects of logistics and distribution, foreign retailers have done very well, has a set of efficient logistics information system, which can effectively improve the inventory turnover rate, so as to enhance the return on assets and profitability、 And domestic retailers in this、area has just started, or have not yet started3、2 distribution center lower the overall distribution, commercial chain failed to give full play to the advantagesFrom our point of view the existing commercial retail enterprises, in addition to some large, well-known commercial enterprises, the general commercial "chain" businesses are not set up their own logistics and distribution centers or use third-party logistics center、Although these companies have also established some of his own "chain" stores, but in fact operating goods stores do not do "unified procurement, unified distribution, unified billing,"、 The which allows some commercial retail enterprises, "chain" seems to exist in name onlyother has been established in their own logistics and distribution centers or use third-party logistics distribution center of commodities in commercial enterprises, the effectiveness of distribution centers has not been effective, which in turn affected the procurement cost of an integrated chain advantages, including outstanding manifested by the distribution center for goods distribution ratio of unity is very low、 Uniform distribution logistics center can notbe achieved, indicating the store's commercial enterprises "unified purchase" did not、materialize, rather than a unified procurement chain has lost the core strengths3、3 China's more enterprises are facing a major obstacle of the higher logistics costWal-Mart 8 5% of the commodities distribution through the distribution center, in which 80% is through the "zero inventory" of the more complete form of the distribution database、Wal-Mart as a result of the use of the "Cross distribution" and "auto-replenishment" of supply chain technology, so that goods turnover in the Treasury down to 2 days、 And retail enterprises in China are in the 15-30 days, which reflects the retail , distribution enterprises, underdeveloped logistics system, distribution costs are too high、 Rapid expansion of retail enterprises in China's size and speed in the short term if they can not form a qualitative edge is a dangerous speculation、Over the years the practice has proved that the multi-purpose logistics distribution center, intensive, low-cost supply hub, as well as the use of information technology to reorganize and upgrade the entire flow of the supply chain management is the core of large-scale retail enterprises strategy is to support the retail giant super-conventional development、The face of large-scale retail and distribution businesses o f the main distribution center logistics requirements planning, focusing on how to reflect the integration of information flow in business flow, logistics, capital flow, so that the operation of retail enterprises to expand the logistics for the entire enterprise supply chain collaboration nodes and so that the whole positive and negative to minimize logistics cost of goods (including consumers, stores, logistics, distribution centers, headquarters, suppliers and partners), and a timely response t o sales demand and timely replenishment、This is also a large-scalecross-regional, multi-format, chain retail enterprises have the capacity of the core competitive advantage、3、4 Lack of modern logistics management knowledge and expertise of logistics personnel、This is the third-party logistics industry in restricting the development of China's most important one of the bottlenecks、Logistics knowledge, especially in modern integrated third party logistics knowledge is far from being universal, but that its main business areas is to provide transportation and warehousing services, not know that it is new to these traditional business integration of its business fields Far too simple to become connected with transport and storage of raw materials, semi-finished products supply, production process, material flow, the whole process of product distribution services, as cover flow, solid logistics, capital flow, information flow is equal to the integrated systemof systems、4 to enhance core competitiveness, the implementation of integrated management"integrated management" is the original English Integrated SupplyProcess, refers to the production enterprises, office, life of a non-core business areas of the operation and management of integration as a Overall, as a business-oriented t o manage outsourcing projects, by the special "integrated management" of the suppliers to provide full-service projects、"Integrated management" is not simply puts together the management of the business, but to improve management efficiency and reduce management costs as the core, combined with advanced information technology and network management features such as one organically integrated、Compared with the general outsourcing services, integrated management has the following characteristics:(1) It is not a business, but a complete outsourcing business from the operation of themanagement integration of outsourcing;(2) Outsourcing is not a core operation, but a comprehensive business management、Responsible for the entire business as a first-class suppliers, and its main task is to use its unique resources to conduct a comprehensive knowledge management, the operation of the specific is it managed by the secondary and tertiary suppliers to implement, so in themanagement of outsourcing functions based on the specific operation of the outsourcing; (3) In the case of the most important first-level suppliers, other than remuneration in thefixed service, its the only way to increase revenue for users to save costs as much as possible in order to share the proceeds of cost savings, rather than as general outsourcing as suppliers, mainly through an increase in turnover, that is, to increase spending to increase the user's own earnings、 "Double bottom" principle of cooperation between the two sides can make a stable and lasting、5 The third party logistics enterprise strategic choiceSummarized the latest of several foreign logistics theory and the development ofthird-party logistics with the current practice of foreign, third-party logistics firm's strategic choice to have the following three:(1)Lean Logistics StrategySince the lag theory and practice of logistics, our most extensive third-party logistics company or business, it can not accurately position their logistics services、 If you do not reverse this situation as soon as possible, will be third-party logistics industry in China have restricted role、 Lean production theory of logistics for our third-party logistics company provides a new development ideas for these enterprises to survive in the new economy and development opportunities、 Lean Logistics concept originated in lean manufacturing、 Itis produced from the Toyota Motor Corporation 70 years in the last century by the original "Toyota Production System", after research by the Massachusetts Institute of Technology professor and summary, was published in 1990 published "change the world of machines), a book、 Lean thinking is the use of various modern management methods and means, based on the needs of society to fully play the role of people as a fundamental and effective allocation and rational use of corporate resources to maximize economic benefits for enterprises to seek a new Management philosophy、 Lean Logistics Lean Thinking is the application in logistics management, logistics development must reflect、The so-called Lean Logistics means: the process by eliminating the production and supply of non-value added waste in order to reduce stocking time, improve customer satisfaction、 The aim ofLean Logistics according to customer needs, providing customers with logistics services, while pursuing the provision of logistics services in the process to minimize waste and delay, the process of increasing value added logistics services、Lean logistics system is characterized by its high-quality, low cost, continuous improvement, driven by customer demand oriented logistics system、 It requires establishing the customer first thought, on time, accurate and fast delivery of goods and information、In short, Lean Logistics, as a new management ideas, bound to have a third-party logistics enterprises in China have far-reaching impact, it will change the appearance of the extensive third party logistics management concept, the formation of third party logistics Core competitiveness、the establishment of small and medium third party logistics value chain allianceThird-party logistics enterprises of small and medium can not be independent because of their one-stop logistics services to provide full shortcomings, and because the small size of assets, services, not wide area so that small and medium enterprises in China's logistics third party logistics industry at a disadvantage、 Therefore, third party logistics for small and medium enterprises, starting from their own resources to construct their own core competence is the key、 As small and medium enterprise features of a single third-party logistics and incomplete, so based on their respective core competencies based on the structure of the logistics business enterprise cooperation is an effective capacity to make up for deficiencies, constitutes a feasible way of competitive advantage of logistics、 Value chain is the use of systems approach to investigate the interaction between business and the、 Value analysis of all activities and their access to the resources of competitive advantageof the business activities fall into two categories: basic activities and support activities、Basic activities are involved in product creation and sale of the material transferred to the buyer and after-sales service activities、 Basic activities of supporting activities is to assistthe revenue by providing outsourcing, technology, human resources and a variety of functions to support each other、 Theory to analyze the value chain study the value of third party logistics chain composition, can be found in auxiliary activities, third party logisticsenterprise and general business is no different, the basic activities in the third-party logistics companies has its own characteristics、 Third-party logistics enterprises there is generally no commodity production process, only the re-circulation process, d oes not account for major components of a wide range of third-party logistics companies and thus become the basic operating activities of storage, transport, packaging, distribution, customer service and marketing, etc、 link、 Various aspects of the basic work activities, due to their own limited resources and capacity, can not have every aspect of an advantage in that value chain in terms of some of the deficiencies, resulting in their overall logistics function not complete, lack of corresponding competitiveness and comparative advantage in some sectors of the value chain due to lack of overall effect should not play、 Therefore, third party logistics industry, small and medium sized logistics enterprises within the Union, should be based on the value chain between complementary on the basis of cooperation, make full use of professional logistics companies and logistics functions of specialized logistics organization and coordination of agents Flexible complementary integrated logistics capabilities、Third-party logistics for small and medium enterprises, value chain should start with the advantage of links to explore and develop the core competitiveness of enterprises, through the reconstruction of the value chain to avoid weaknesses、(2)Large third-party logistics enterprise virtualization of strategyRapid development in IT and the Internet era, companies can not fight alone singles, but must be in the competition and collaboration, in cooperation and development、Thus, under modern conditions resulting from modern large-scale virtualized development of third-party logistics has a strong necessity、Large third-party logistics enterprise virtualization is the logistics management resources of others who will have "all", through the network, the other part into its own logistics, with the help of others break the power of physical boundaries, extending to achieve their various Function, and thus expand their ability to enhance their strength、Therefore, the logistics information technology, virtualization is a means for the connection and coordination of temporary and dynamic alliance in the form of virtual logistics、 Integrated logistics virtualization technology as ameans of electronic communication, customer-focused, based on the opportunity to participate in members of the core competencies as a condition to an agreement for the common pursuit of goals and tasks, the different parts of the country's existing Resources to quickly mix into a no walls, beyond the space constraints, by means of electronic networks, contact the unified command of the virtual business entity, the fastest launch of high-quality, low-cost logistics service、Modern large-scale virtualization, including third-party logistics functions, organization, geographic three virtualization、Virtualization capabilities with third-party logistics enterprise IT technology will be distributed in different locations, different companies take different functions within the logistics resources (information, human, material and other resources) organized to accomplish a specific task, to achieve the optimization of social resources、 Virtualization refers to the organizational structure of the logistics organization is always dynamically adjusted, not fixed, but also decentralized, flexible, self-management, flat network structure, its objectives and in accordance with changes in the environmentre-combination, in a timely manner Reflect the market dynamics、 Virtual is the regional third party logistics network through the Internet link the global logistics resources, removing barriers and national barriers, to production management to achieve "virtual neighbors、 "1 导言物流通常被认为就是将恰当的产品以最低的成本,在恰当的时间送达恰当的地点。
外文翻译及文献综述
2 无线射频系统(RFID)的原理及安全性分析
2.1 RFID系统概述 RFID系统一般由三部分组成[3]： 标签(Tag)：它是RFID的核心部件,主要包括用于收 发信息的藕合元件和一块微控制芯片组成,芯片内存 有唯一的电子编码； 阅读器(Reader)：用来对标签进行读写操作的设备； 天线(Antenna)：传递射频信号必需的收发装置。
毕业设计过程中阅读的和课题注意是 “和课题相关的”。不要选择 和课题无关的外文资料进行翻译。
3.1.3 外文翻译工具
谷歌翻译(/#) 有道翻译(/) 爱词霸翻译(http://fy.iciba. com/)
(3) Chien和Chen于2007年提出了一个符合EPC Class 1 Generation 2 的 RFID双向认证协议[18]
(4) Tassos Dimitriou等人提出的安全与效率兼得的协议
6 小结
虽然RFID技术在各行各业中有良好的应用前景，但如果不能很好 地解决隐私、追踪等安全问题，这种应用前景难以变成现实的产 业，因此，对RFID安全协议进行研究具有比较重要的意义。 本文首先对RFID系统进行了大致的描述，包括RFID系统的结构 及其原理，并针对在RFID系统上存在的一些隐私与安全隐患做了 细致分析，指出了在RFID系统上采用安全措施的必要性。同时从 多个角度阐述了一些RFID安全机制，重点介绍了基于密码技术的 RFID协议，文中又可分为基于杂凑的安全协议和其他密码学机制 的安全协议，并对文中提到的每一个协议给出了详细的通信流程， 分析了这些协议的缺陷。 随着RFID技术成本的降低和技术的成熟，人们将会越来越重视 RFID的安全性问题。我们相信,在不久的将来，RFID安全与隐私 问题一定能得到进一步完善的解决，同时RFID技术也一定会全面 普及。
英文翻译 附原文
本科毕业设计(论文) 外文翻译（附外文原文）系 ( 院 )：资源与环境工程系课题名称：英文翻译专业(方向)：环境工程班级：2004-1班学生：3040106119指导教师：刘辉利副教授日期：2008年4月20使用褐煤（一种低成本吸附剂）从酸性矿物废水中去除和回收金属离子a. 美国, 大学公园, PA 16802, 宾夕法尼亚州立大学, 能源部和Geo 环境工程学.b. 印度第80号邮箱, Mahatma Gandhi ・Marg, Lucknow 226001, 工业毒素学研究中心, 环境化学分部,于2006 年5月6 日网上获得，2006 年4月24 日接受，2006 年3月19 日;校正，2006 年2月15 日接收。
摘要酸性矿物废水(AMD), 是一个长期的重大环境问题，起因于钢硫铁矿的微生物在水和空气氧化作用, 买得起包含毒性金属离子的一种酸性解答。
这项研究的主要宗旨是通过使用褐煤（一种低成本吸附剂）从酸性矿水(AMD)中去除和回收金属离子。
褐煤已被用于酸性矿水排水AMD 的处理。
经研究其能吸附亚铁, 铁, 锰、锌和钙在multi-component 含水系统中。
研究通过在不同的酸碱度里进行以找出最适宜的酸碱度。
模拟工业条件进行酸性矿物废水处理, 所有研究被进行通过单一的并且设定多专栏流动模式。
空的床接触时间(EBCT) 模型被使用为了使吸附剂用量减到最小。
金属离子的回收并且吸附剂的再生成功地达到了使用0.1 M 硝酸不用分解塔器。
关键词:吸附; 重金属; 吸附; 褐煤; 酸性矿物废水处理; 固体废料再利用; 亚铁; 铁; 锰。
文章概述1. 介绍2. 材料和方法2.1. 化学制品、材料和设备3. 吸附步骤3.1. 酸碱度最佳化3.2. 固定床研究3.2.1 单一栏3.2.2 多栏4. 结果和讨论4.1. ZPC 和渗析特征4.2 酸碱度的影响4.3. Multi-component 固定吸附床4.3.1 褐煤使用率4.4. 吸附机制4.5. 解吸附作用研究5. 结论1. 介绍酸性矿物废水(AMD) 是一个严重的环境问题起因于硫化物矿物风化, 譬如硫铁矿(FeS2) 和它的同素异形体矿物(α-FeS) 。
外文翻译
井冈山大学外文翻译题目施工组织设计与施工图预算学院建筑工程学院专业工程管理姓名谭智强学号90617008指导教师夏振华2012年11月20日开发一个评估施工现场安全管理系统有效性的模型Developing a model to measure the effectiveness of safety management systems of construction sites作者：Evelyn Ai Lin Teoa,_, Florence Yean Yng Linga起止页码：1584~1592出版日期（期刊号）：2005年6月第005版出版单位：新加坡环境国立大学摘要:在新加坡,实施了建筑行业安全管理系统(SMS)和SMS审计大约有十年之久的现在,安全标准的提高并不显著。
为了回应需要改进的有效性(SMS)和安全管理体系审计的目的,本文提出了一种方法, 人员可以利用测试工具来评估审计建筑公司安全管理体系的有效性。
研究方法采用了15个步进行调查，安全专家被邀请通过面试或工作表达自己的意见。
层次分析法(AHP)及因子分析是用来协助识别影响最为关键的因素和属性的安全。
该模型开发利用多属性值模型(MAVT)的方法。
该方法可以通过网站得到验证审核,利用模型中施工安全指数(CSI)可以计算出来。
结果表明,该模型可以作为一个客观CSI衡量不同管理和评估。
关键词: 安全管理体系;安全审核;施工安全指数1 简介: 支撑这一工作的论据安全管理体系(SMS)作为建筑业一个正式制度的管理现场安全的体系。
承包商预期管理现场安全通过正常的安全管理体系。
如何有效地评价这些系统是很重要的,这样可以使不足之处得以更正。
该研究工作是在协作与职业安全部门监督下进行的,人力资源部门可根据当局评价审计协议来衡量一个建筑工地的有效性的安全管理体系。
新加坡建筑行业服务实施了安全管理体系审计大约有十年之久了,但是提高的安全效果并不显著。
这与影响船舶的修建行业一样,经历了一个稳定提高安全性能的阶段。
四旋翼飞行器中英文对照外文翻译文献
四旋翼飞⾏器中英⽂对照外⽂翻译⽂献四旋翼飞⾏器中英⽂对照外⽂翻译⽂献(⽂档含英⽂原⽂和中⽂翻译)译⽂：四旋翼飞⾏器的建模与控制摘要迄今为⽌，⼤多数四旋翼空中机器⼈取材于飞⾏玩具。
虽然这样的系统可以作为原型，但是它们是还没有健全到能够服务于所有实验机器⼈平台。
我们已经开发出了X‐4，采⽤定制底盘和带有现成的电机和电池航空电⼦设备，是⼀个⾼度可靠的实验平台。
这个飞⾏器使⽤嵌⼊式姿态动⼒学控制器以稳定飞⾏。
被⽤来调节飞⾏器的姿态的控制器是⼀个线性的单输⼊单输出系统。
1 介绍直升机的⼀个主要难点是为了可靠的飞⾏，飞⾏器需要⼴泛的，和昂贵的维修费⽤。
⽆⼈驾驶航空飞⾏器（⽆⼈机）和微型飞⾏（MAV）也不例外。
简化飞⾏器的机械结构能够⽅便操控这些飞⾏器。
四旋翼是⼀种强⼤且简单的直升机，因为他们没有传统旋翼飞⾏器的复杂旋转倾转盘和联系。
多数四转⼦飞⾏器是根据遥控玩具的组件构建⽽成的。
因此，这些缺少必要的可靠性和性能的飞⾏器是不可能成为是切实可⾏的实验平台的。
1.1 ⽬前的四旋翼平台最近⼏个四转⼦⼯艺已被开发⽤于制作玩具或进⾏研究。
因为市场的需求，许多关于四旋翼的研究开始了，如HMX2‐4 和Rctoys 的Draganflyer。
⼀成不变的，这些由塑料电机组成的飞⾏器的机⾝都带灯光。
它们是由镍镉电池或锂聚合物电池供电，并且使⽤基于速度反馈的mems陀螺仪。
这些四旋翼⼀般没有稳定的稳态。
⾃动稳定及使⽤各种硬件和控制⽅案被⽤于研究四旋翼。
例如，CSIRO的四旋翼飞⾏器，是⼀个Draganflyer的衍⽣物，它使⽤视觉伺服和惯性测量单元（IMU）来使飞⾏器稳定在⼀个固定的点上。
其他的四旋翼，包括Eidgenossische Technische Hochschule Zurich的‘OS4’，⼀个带有低纵横⽐的叶⽚的带传动的飞⾏器; CEA 的“X4‐flyer'1，⼀个带有四个电机和叶⽚的四旋翼]。
还有康奈尔⼤学的⾃治飞⾏器，⼀个采⽤的飞机螺旋桨的⼤型飞⾏器。
外文翻译要求
外文翻译要求
一、外文翻译的目的：
通过外文文献查阅与翻译，熟悉本专业主要的外文书刊，了解毕业设计课题的国内外发展现状和发展趋势及其使用的技术手段和研究方法，进一步提高对外文的阅读应用能力。
二、外文翻译的内容:
阐述所选课题在相应学科领域中的发展进程和研究方向，特别是近年来的发展趋势和最新成果。
可以是系统业务上的文档，也可以是系统涉及到的技术手段的文档。
三、外文翻译的要求：
1.需符合学校相关要求。
3.需认真研读和查阅术语完成翻译，保证翻译语句流畅。
4.翻译的外文文献应主要选自学术期刊、学术会议的文章、有关著作及其他相关材料，应与毕业设计主题相关，并作为外文参考文献列入毕业设计的参考文献。
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5 中英文翻译
外文参考文献全文及译文英文原文4.1 DefinitionA durable lining is one that performs satisfactorily in the working environment during its anticipated service life. The material used should be such as to maintain its integrity and, if applicable, to protect other embedded materials.4.2 Design lifeSpecifying the required life of a lining (see Section 2.3.4) is signifi-cant in the design, not only in terms of the predicted loadings but also with respect to long-term durability. Currently there is no guide on how to design a material to meet a specified design life, although the new European Code for Concrete (British Standards Institution, 2003) addresses this problem. This code goes some way to recommending various mix proportions and reinforcement cover for design lives of 50 and 100 years. It can be argued that linings that receive annular grouting between the excavated bore and the extrados of the lining, or are protected by primary linings, for example sprayed concrete, may have increased resistance to any external aggressive agents. Normally, these elements of a lining system are considered to be redundant in terms of design life. This is because reliably assessing whether annulus grouting is complete or assessing the properties or the quality of fast set sprayed concrete with time is generally difficult.Other issues that need to be considered in relation to design life include the watertightness of a structure and fire-life safety. Both of these will influence the design of any permanent lining.4.3 Considerations of durability related to tunnel useLinings may be exposed to many and varied aggressive environments. Durability issues to be addressed will be very dependent not only on the site location and hence the geological environment but also on the use of the tunnel/shaft (see Fig. 4.1).The standards of material, design and detailing needed to satisfy durability requirements will differ and sometimes conflict. In these cases a compromise must be made to provide the best solution possible based on the available practical technology.4.4 Considerations of durability related to tunnel4.4.1 Steel/cast-iron liningsUnprotected steel will corrode at a rate that depends upon the temperature, presence of water with reactive ions (from salts and acids) and availability of oxygen. Typically corrosion rates can reach about 0.1 mm/year. If the availability of oxygen is limited, for example at the extrados of a segmental lining, pitting corrosion is likely to occur for which corrosion rates are more difficult to ascertain.Grey cast-iron segments have been employed as tunnel linings for over a hundred years, with little evidence as yet of serious corrosion. This is because this type of iron contains flakes of carbon that become bound together with the corrosion product to prevent water and, in ventilated tunnels, oxygen from reaching the mass of the metal. Corrosion is therefore stifled. This material is rarely if ever used in modern construction due to the higher strength capacities allowed with SGI linings.Spheroidal-Graphite cast iron (SGI) contains free carbon in nodules rather than flakes, and although some opinion has it that this will reduce the self-stifling action found in grey irons, one particular observation suggests that this is not necessarily so. A 250 m length of service tunnel was built in 1975 for the Channel Tunnel, and SGI segments were installed at the intersection with the tunnel constructed in 1880. The tunnel was mainly unventilated for the next ten years, by which time saline groundwater had caused corrosion and the intrados appeared dreadfully corroded. The application of some vigorous wire brushing revealed that the depth of corrosion was in reality minimal.4.4.2 Concrete liningsIn situ concrete was first used in the UK at the turn of the century. Precast concrete was introduced at a similar time but it was not used extensively until the 1930s. There is therefore only 70 to 100 years of knowledge of concrete behaviour on which to base the durability design of a concrete lining.The detailed design, concrete production and placing, applied curing and post curing exposure, and operating environment of the lining all impact upon its durability. Furthermore, concrete is an inherently variable material. In order to specify and design to satisfy durability requirements, assumptions have to be made about the severity of exposure in relation to deleterious agents, as well as the likely variability in performance of the lining material itself. The factors that generally influence the durability of the con-crete and those that should be considered in the design and detailing of a tunnel lining include:1.operational environment2.shape and bulk of the concrete3.cover to the embedded steel4.type of cement5.type of aggregate6.type and dosage of admixture7.cement content and free water/cement ratio8.workmanship, for example compaction’ finishing, curing9.permeability, porosity and dijfusivity of the final concrete.The geometric shape and bulk of the lining section is important because concrete linings generally have relatively thin walls and are possibly subject to a significant external hydraulic head. Both of these will increase the ingress of aggressive agents into the concrete.4.5 Design and specification for durabilityIt has to be accepted that all linings will be subject to some level of corrosion and attack by both the internal and external environment around a tunnel. They will also be affected by fire. Designing for durability is dependent not only on material specification but also on detailing and design of the lining.4.5.1 Metal liningsOccasionally segments are fabricated from steel, and these should be protected by the application of a protective system. Liner plates formed from pressing sheet steel usually act as a temporary support while an in situ concrete permanent lining is constructed. They are rarely protected from corrosion, but if they are to form a structural part of the lining system they should also be protected by the application of a protective system. Steel sections are often employed as frames for openings and to create small structures such as sumps. In these situations they should be encased in con-crete with suitable cover and anti-crack reinforcement. In addition, as the quality of the surrounding concrete might not be of a high order consideration should be given to the application of a protec-tive treatment to such steelwork.Spheroidal-Graphite cast iron segmental tunnel linings are usually coated internally and externally with a protective paint system. They require the radial joint mating surfaces, and the circumferential joint surfaces, to be machined to ensure good load transfer across thejoints and for the formation of caulking and sealing grooves. It is usual to apply a thin coat of protective paint to avoid corrosion between fabrication and erection, but long-term protective coatings are unnecessary as corrosion in such joints is likely to be stifled.It is suggested that for SGI segmental linings the minimum design thicknesses of the skin and outer flanges should be increased by one millimetre to allow for some corrosion (see Channel Tunnel case history in Chapter 10). If routine inspections give rise to a concern about corrosion it is possible to take action, by means of a cathodic protection system or otherwise, to restrain further deterioration. The chance of having to do this over the normal design lifetime is small.(1)Protective systemsCast iron segmental linings are easily protected with a coating of bitumen, but this material presents a fire hazard, which is now unacceptable on the interior of the tunnel. A thin layer, up to 200 um in thickness, of specially formulated paint is now employed; to get the paint to adhere it is necessary to specify the surface preparation. Grit blasting is now normally specified, however, care should be taken in the application of these coatings. The problem of coatings for cast iron is that grit blasting leavesbehind a surface layer of small carbon particles, which prevents the adhesion of materials, originally designed for steelwork, and which is difficult to remove. It is recommended that the designer take advice from specialist materials suppliers who have a proven track record.Whether steel or cast iron segments are being used, consideration of the ease with which pre-applied coatings can be damaged during handling, erection and subsequent construction activities in the tunnel is needed.(2) Fire resistanceExperiences of serious fires in modern tunnels suggest that temperatures at the lining normally average 600-700 °C, but can reach 1300 °C (see Section 4.5.3). It is arguable that fire protection is not needed except where there is a risk of a high-temperature (generally hydrocarbon) fire. It can be difficult to find an acceptable economic solution, but intumescent paint can be employed. This is not very effective in undersea applications. As an alternative an internal lining of polypropylene fibre reinforced concrete might be considered effective. 4.5.2 Concrete liningsAll aspects of a lining’s behaviour during its design life, both under load and within theenvironment, should be considered in order to achieve durability. The principle factors that should be considered in the design and detailing are:1.Material(s)2.production method3.application method (e.g. sprayed concrete)4.geological conditions5.design life6.required performance criteria.(1) CorrosionThe three main aspects of attack that affect the durability of concrete linings are:corrosion of metalschloride-induced corrosion of embedded metalscarbonation-induced corrosion of embedded metals.Corrosion of metalsUnprotected steel will corrode at a rate that depends upon temperature, presence of water and availability of oxygen. Exposed metal fittings, either cast in (i.e. a bolt- or grout-socket), or loose (e.g. a bolt), will corrode (see Section 4.5.4). It is impractical to provide a comprehensive protection system to these items and it is now standard practice to eliminate ferrous cast in fittings totally by the use of plastics. Loose fixings such as bolts should always be specified with a coating such as zinc.Chloride-induced corrosionCorrosion of reinforcement continues to represent the single largest cause of deterioration of reinforced concrete structures. Whenever there are chloride ions in concrete containing embedded metal there is a risk of corrosion. All constituents of concrete may contain some chlorides and the concrete may be contaminated by other external sources, for example de-icing salts and seawater.Damage to concrete due to reinforcement corrosion will only normally occur when chloride ions, water and oxygen are all present.Chlorides attack the reinforcement by breaking down the passive layer around the reinforcement. This layer is formed on the surface of the steel as a result of the highly alkaline environment formed by the hydrated cement. The result is the corrosion of the steel, whichcan take the form of pitting or general corrosion. Pitting corrosion reduces the size of the bar, while general corrosion will result in cracking and spalling of the concrete.Although chloride ions have no significant effect on the per-formance of the concrete material itself, certain types of concrete are more vulnerable to attack because the chloride ions then find it easier to penetrate the concrete. The removal of calcium alumi- nate in sulphate-resistant cement (the component that reacts with external sulphates), results in the final concrete being less resistant to the ingress of chlorides. To reduce the penetration of chloride ions, a dense impermeable concrete is required. The use of corrosion inhibitors does not slow down chloride migration but does enable the steel to tolerate high levels of chloride before corrosion starts.Current code and standard recommendations to reduce chloride attack are based on the combination of concrete grade (defined by cement content and type, water/cement ratio and strength, that is indirectly related to permeability) and cover to the reinforcement. The grade and cover selected is dependent on the exposure condition. There are also limits set on the total chlorides content of the concrete mix.Carbonation-induced corrosionIn practice, carbonation-induced corrosion is regarded as a minor problem compared with chloride- induced corrosion. Even if carbonation occurs it is chloride-induced corrosion that will generally determine the life of the lining. Carbonated concrete is of lower strength but as carbonation is lim-ited to the extreme outer layer the reduced strength of the concrete section is rarely significant.Damage to concrete will only normally occur when carbon dioxide, water, oxygen and hydroxides are all present. Carbonation is unlikely to occur on the external faces of tunnels that are constantly under water, whereas some carbonation will occur on the internal faces of tunnels that are generally dry. Carbonation-induced corrosion, how-ever, is unlikely in this situation due to lack of water. Linings that are cyclically wet and dry are the most vulnerable.When carbon dioxide from the atmosphere diffuses into the concrete, it combines with water forming carbonic acid. This then reacts with the alkali hydroxides forming carbonates. In the presence of free water, calcium carbonate is deposited in the pores. The pH of the pore fluid drops from a value of about 12.6 in the uncarbonated region to 8 in the carbonated region. If this reduction in alkalinity occurs close to the steel, it can cause depassivation. Inthe presence of water and oxygen corrosion of the reinforcement will then occur.To reduce the rate of carbonation a dense impermeable concrete is required.As with chloride-induced corrosion, current code and standard recommendations to reduce carbonation attack are based on the combination of concrete grade and reinforcement cover.Other chemical attackChemical attack is by direct attack either on the lining material or on any embedded materials, caused by aggressive agents being part of the contents within the tunnel or in the ground in the vicinity of the tunnel. Damage to the material will depend on a number of factors including the concentration and type of chemical in question, and the movement of the ground-water, that is the ease with which the chemicals can be replenished at the surface of the concrete. In this respect static water is generally defined as occurring in ground having a mass permeability of <10-6m/s and mobile water >10-6 m/s. The following types of exchange reactions may occur between aggressive fluids and components of the lining material:●sulphate attack●acid attack●alkali-silica reaction (ASR).Sulphates (conventional and thaumasite reaction)In soil and natural groundwater, sulphates of sodium, potassium, magnesium and calcium are common. Sulphates can also be formed by the oxi-dation of sulphides, such as pyrite，as a result of natural processes or with the aid of construction process activities. The geological strata most likely to have a substantial sulphate concentration are ancient sedimentary clays. In most other geological deposits only the weathered zone (generally 2m to 10m deep) is likely to have a significant quantity of sulphates present. By the same processes, sulphates can be present in contaminated ground. Internal corro-sion in concrete sewers will be, in large measure, due to the presence of sulphides and sulphates at certain horizons dependent on the level of sewer utilisation. Elevated temperatures will contribute to this corrosion.Ammonium sulphate is known to be one of the salts most aggressive to concrete. However, there is no evidence that harmful concentrations occur in natural soils.Sulphate ions primarily attack the concrete material and not the embedded metals. They are transported into the concrete in water or in unsaturated ground, by diffusion. The attackcan sometimes result in expansion and/or loss of strength. Two forms of sulphate attack are known; the conventional type leading to the formation of gypsum and ettringite, and a more recently identified type produ-cing thaumasite. Both may occur together.Constituents of concrete may contain some sulphates and the concrete may be contaminated by external sources present in the ground in the vicinity of the tunnel or within the tunnel.Damage to concrete from conventional sulphate reaction will only normally occur when water, sulphates or sulphides are all present. For a thaumasite-producing sulphate reaction, in addition to water and sulphate or sulphides, calcium silicate hydrate needs to be present in the cement matrix, together with calcium carbonate. In addition, the temperature has to be relatively low (generally less than 15 °C).Conventional sulphate attack occurs when sulphate ions react with calcium hydroxide to form gypsum (calcium sulphate), which in turn reacts with calcium aluminate to form ettringite. Sulphate resisting cements have a low level of calcium aluminate so reducing the extent of the reaction. The formation of gypsum and ettringite results in expansion and disruption of the concrete.Sulphate attack, which results in the mineral thaumasite, is a reaction between the calcium silicate hydrate, carbonate and sulphate ions. Calcium silicate hydrate forms the main binding agent in Portland cement, so this form of attack weakens the con-crete and, in advanced cases, the cement paste matrix is eventually reduced to a mushy, incohesive white mass. Sulphate resisting cements are still vulnerable to this type of attack.Current code and standard recommendations to reduce sulphate attack are based on the combination of concrete grade. Future code requirements will also consider aggregate type. There are also limits set on the total sulphate content of the concrete mix but, at present, not on aggregates, the recommendations of BRE Digest 363 1996 should be followed for any design.AcidsAcid attack can come from external sources, that are present in the ground in the vicinity of the tunnel, or from within the tunnel. Groundwater may be acidic due to the presence of humic acid (which results from the decay of organic matter), carbonic acid or sulphuric acid. The first two will not produce a pH below 3.5. Residual pockets of sulphuric (natural andpollution), hydrochloric or nitric acid may be found on some sites, particularly those used for industrial waste. All can produce pH values below 3.5. Carbonic acid will also be formed when carbon dioxide dissolves in water.Concrete subject to the action of highly mobile acidic water is vulnerable to rapid deterioration. Acidic ground waters that are not mobile appear to have little effect on buried concrete.Acid attack will affect both the lining material and other embedded metals. The action of acids on concrete is to dissolve the cement hydrates and, also in the case of aggregate with high calcium carbonate content, much of the aggregate. In the case of concrete with siliceous gravel, granite or basalt aggregate the sur-face attack will produce an exposed aggregate finish. Limestone aggregates give a smoother finish. The rate of attack depends more on the rate of movement of the water over the surface and the quality of the concrete, than on the type of cement or aggregate.Only a very high density, relatively impermeable concrete will be resistant for any period of time without surface protection. Damage to concrete will only normally occur when mobile water conditions are present.Current code and standard recommendations to reduce acid attack are based on the concrete grade (defined by cement content and type, water/cement ratio and strength). As cement type is not significant in resisting acid attack, future code requirements will put no restrictions on the type used.(2) Alkali Silica Reaction (ASR)Some aggregates contain particular forms of silica that may be susceptible to attack by alkalis originat-ing from the cement or other sources.There are limits to the reactive alkali content of the concrete mix, and also to using a combination of aggregates likely to be unreactive. Damage to concrete will only normally occur when there is a high moisture level within the concrete, there is a high reactivity alkali concrete content or another source of reactive alkali, and the aggregate contains an alkali-reactive constituent. Current code and standard recommendations to reduce ASR are based on limiting the reactive alkali content of the concrete mix, the recommendations of BRE 330 1999 should be followed for any design.(3) Physical processesVarious mechanical processes including freeze-thaw action, impact, abrasion and cracking can cause concrete damage.Freeze-thawConcretes that receive the most severe exposure to freezing and thawing are those which are saturated during freezing weather, such as tunnel portals and shafts.Deterioration may occur due to ice formation in saturated con-crete. In order for internal stresses to be induced by ice formation, about 90% or more by volume of pores must be filled with water. This is because the increase in volume when water turns to ice is about 8% by volume.Air entrainment in concrete can enable concrete to adequately resist certain types of freezing and thawing deterioration, provided that a high quality paste matrix and a frost-resistant aggregate are used.Current code and standard recommendations to reduce freeze- thaw attack are based on introducing an air entrainment agent when the concrete is below a certain grade. It should be noted that the inclusion of air will reduce the compressive strength of the concrete.ImpactAdequate behaviour under impact load can generally be achieved by specifying concrete cube compressive strengths together with section size, reinforcement and/or fibre content. Tensile capacity may also be important, particularly for concrete without reinforcement.AbrasionThe effects of abrasion depend on the exact cause of the wear. When specifying concrete for hydraulic abrasion in hydraulic applications, the cube compressive strength of the concrete is the principal controlling factor.CrackingThe control of cracks is a function of the strength of concrete, the cover, the spacing, size and position of reinforce-ment, and the type and frequency of the induced stress. When specifying concrete cover there is a trade-off between additional protection from external chloride attack to the reinforcement, and reduction in overall strength of the lining.4.5.3 Protective systemsAdequate behaviour within the environment is achieved by specify-ing concrete to thebest of current practice in workmanship and materials. Protection of concrete surfaces is recommended in codes and standards when the level of aggression from chemicals exceeds a maximum specified limit. Various types of surface protection include coatings, waterproof barriers and a sacrificial layer.(1) CoatingsCoatings have changed over the years, with tar and cut-back bitumens being less popular, and replaced by rubberised bitumen emulsions and epoxy resins. The fire hazard associated with bituminous coatings has limited their use to the extrados of the lining in recent times. The risk of damage to coat-ings during construction operations should be considered.(2) Waterproof barriersThe requirements for waterproof barriers are similar to those of coatings. Sheet materials are commonly used, including plastic and bituminous membranes. Again, the use of bituminous materials should be limited to the extrados.(3) Sacrificial layerThis involves increasing the thickness of the concrete to absorb all the aggressive chemicals in the sacrificial outer layer. However, use of this measure may not be appropriate in circumstances where the surface of the concrete must remain sound, for example joint surfaces in segmental linings.(4) Detailing of precast concrete segmentsThe detailing of the ring plays an important role in the success of the design and performance of the lining throughout its design life. The ring details should be designed with consideration given to casting methods and behaviour in place. Some of the more important considerations are as follows.4.5.5 Codes and standardsBuilding Research Establishment (BRE) Digest 330: 1999 (Building Research Establishment, 1999), Building Research Establishment (BRE) Digest 363: 1996 (Building Research Establishment, 1996)，BRE Special Digest 1 (Building Research Establishment, 2003) and British Standard BSEN 206-1: 2000 (British Standards Institution, 2003) are the definitive reference points for designing concrete mixes which are supplemented by BS8110 (British Standards Institution, 1997) and BS 8007 (British Standards Institution, 1987). BSEN 206-1 also references Eurocode 2: Design of Concrete Structures (European Commission,1992).(1) European standardsEN206 Concrete - Performance, Production and Conformity, and DD ENV 1992-1-1 {Eurocode 2: Design of Concrete Structures Part 1) (British Standards Institution, 2003 and European Commission，1992).Within the new European standard EN 206 Concrete - Perfor-mance, Production and Conformity，durability of concrete will rely on prescriptive specification of minimum grade, minimum binder content and maximum water/binder ratio for a series of defined environmental classes. This standard includes indicative values of specification parameters as it is necessary to cover the wide range of environments and cements used in the EU member states.Cover to reinforcement is specified in DD ENV 1992-1 -1 (Eurocode 2: Design of Concrete Structures Part 1 - European Commission, 1992).(2) BRE 330:1999This UK Building Research Establishment code (Building Research Establishment, 1999) gives the back-ground to ASR as well as detailed guidance for minimising the risks of ASR and examples of the methods to be used in new construction.(3) Reinforcement BRE 363: 1996This UK Building Research Establishment code (Building Research Establishment, 1996) discusses the factors responsible for sulphate and acid attack on concrete below ground level and recommends the type of cement and quality of concrete to provide resistance to attack. (4) BRE Special Digest 1This special digest (Building Research Establishment, 2003) was published following the recent research into the effects of thaumasite on concrete. It replaces BRE Digest 363: 2001. Part 4 is of specific reference to precast concrete tunnel linings.(5) BS 8110/BS 8007Guidance is given on minimum grade, minimum cement and maximum w/c ratio for different conditions of exposure. Exposure classes are mild, moderate, severe, very severe, most severe and abrasive related to chloride attack, carbonation and freeze-thaw. The relationship between cover of the reinforcement and concrete quality is also given together with crack width (British Standards Institution, 1987a and 1997a).(6) OthersChemically aggressive environments are classified in specialist standards. For information on industrial acids and made up ground, reference may be made to a specialist producer of acid resistant finishes or BS 8204-2 (British Standards Institu-tion, 1999). For silage attack, reference should be made to the UK Ministry of Agriculture, Fisheries and Food.中文翻译4.1 定义耐用的衬砌指的是在衬砌的预期服务寿命内提供令人满意的工作环境。
外文翻译
Abs t ract : Ubiquitous comp uti ng s ys tems t ypically have lots of securit y p roblems i n t he a rea of i dentit y a ut hentication by mea ns of classical P KI met hods . The li mited comp uti ng resources , t he disconnection network , t he classification requirements of i dentit y a ut hentication , t he requirement of t rust t ra nsfer a nd cross i dentit y a ut hentication , t he bi2 di rectional i dentit y a ut hentication , t he securit y delegation a nd t he si mple p rivacy p rotection etc a re all t hese uns olved p roblems . In t his p aper , a new novel ubiquitous comp uti ng i dentit y a ut hentication mecha nis m , na med U CIAMdess , is p resented. It is based on D2S Evi dence Theory a nd extended S P KI/ SDSI. D2S Evi dence Theory is used i n UCIAMdess to comp ute t he t rus t val ue f rom t he ubiquitous comp uti ng environment to t he p ri ncip al or between t he different ubiquitous comp uti ng envi ronments . S P KI2based a ut horization is exp a nded by a ddi ng t he t rus t certificate i n U CIAMdess to s olve above p roblems i n t he ubiquit ous comp uti ng environments . The i dentit y a ut hentication mecha nis m a nd t he algorit hm of certificate reduction a re given i n t he p ap er to s olve t he multi2levels t rus t2correlative i dentit y a ut hentication p roblems . The perf orma nce a nalyses s how t hat U CIAMdess is a s uit able securit y mecha nis m i n s olvi ng t he complex ubi quitous comp uti ng p roblems . Key words : ubiquitous com puting ; i dentit y authentication mechanism ; D2S Evi dence T heory ; S P K I/ S D S I ; secu rit y
外文翻译及外文原文(参考格式)
外文翻译要求：1、外文资料与毕业设计（论文）选题密切相关，译文准确、质量好。
2、阅读2篇幅以上（10000字符左右）的外文资料，完成2篇不同文章的共2000汉字以上的英译汉翻译3、外文资料可以由指导教师提供，外文资料原则上应是外国作者。
严禁采用专业外语教材文章。
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插图内文字及图名也译成中文。
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下页附：外文翻译与原文参考格式英文翻译 (黑体、四号、顶格)外文原文出处：(译文前列出外文原文出处、作者、国籍，译文后附上外文原文)《ASHRAE Handbook —Refrigeration 》.CHAPTER3 .SYSTEM Practices for ammonia 3.1 System Selection 3.2 Equipment3.10 Reciprocating Compressors第3章 氨制冷系统的实施3.1 系统选择在选择一个氨制冷系统设计时，须要考虑一些设计决策要素，包括是否采用（1）单级压缩（2）带经济器的压缩（3）多级压缩（4）直接蒸发（5）满液式（6）液体再循环（7）载冷剂。
单级压缩系统基本的单级压缩系统由蒸发器、压缩机、冷凝器、储液器（假如用的话）和制冷剂控制装置（膨胀阀、浮球阀等）。
1997 ASHRAE 手册——“原理篇”中的第一章讨论了压缩制冷循环。
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DATA CLASSIFICATION USING SUPPORT VECTORMACHINE1DURGESH K. SRIVASTAVA, 2LEKHA BHAMBHU1Ass. Prof., Department of CSE/IT, BRCM CET, Bahal, Bhiwani, Haryana, India-1270282Ass. Prof, Department of CSE/IT, BRCM CET, Bahal, Bhiwani, Haryana, India-127028ABSTRACTClassification is one of the most important tasks for different application such as text categorization, tone recognition, image classification, micro-array gene expression, proteins structure predictions, data Classification etc. Most of the existing supervised classification methods are based on traditional statistics, which can provide ideal results when sample size is tending to infinity. However, only finite samples can be acquired in practice. In this paper, a novel learning method, Support Vector Machine (SVM), is applied on different data (Diabetes data, Heart Data, Satellite Data and Shuttle data) which have two or multi class. SVM, a powerful machine method developed from statistical learning and has made significant achievement in some field. Introduced in the early 90’s, they led to an explosion of interest in machine learning. The foundations of SVM have been developed by Vapnik and are gaining popularity in field of machine learning due to many attractive features and promising empirical performance. SVM method does not suffer the limitations of data dimensionality and limited samples [1] & [2].In our experiment, the support vectors, which are critical for classification, are obtained by learning from the training samples. In this paper we have shown the comparative results using different kernel functions for all data samples.Keywords: Classification, SVM, Kernel functions, Grid search.1.INTRODUCTIONThe Support Vector Machine (SVM) was first proposed by Vapnik and has since attracted a high degree of interest in the machine learning research community [2]. Several recent studies have reported that the SVM (support vector machines) generally are capable of delivering higher performance in terms of classification accuracy than the other data classification algorithms. Sims have been employed in a wide range of real world problems such as text categorization, hand-written digit recognition, tone recognition, image classification and object detection, micro-array gene expression data analysis, data classification. It has been shown that Sims is consistently superior to other supervised learning methods. However, for some datasets, the performance of SVM is very sensitive to how the cost parameter and kernel parameters are set. As a result, the user normally needs to conduct extensive cross validation in order to figure out the optimal parameter setting. This process is commonly referred to as model selection. One practical issue with model selection is that this process is very time consuming. We have experimented with a number of parameters associated with the use of the SVM algorithm that can impact the results. These parameters include choice of kernel functions, the standard deviation of the Gaussian kernel, relative weights associated with slack variables to account for the non-uniform distribution of labeled data, and the number of training examples.For example, we have taken four different applications data set such as diabetes data, heart data and satellite data which all have different features, classes, number of training data and different number of testing data. These all data taken from RSES data set and /~mlearn/MLRepository.html [5]. This paper is organized as follows. In next section, we introduce some related backgroundincluding some basic concepts of SVM, kernel function selection, and model selection (parameters selection) of SVM. In Section 3, we detail all experiments results. Finally, we have some conclusions and feature direction in Section 4.2. SUPPORT VECTOR MACHINEIn this section we introduce some basic concepts of SVM, different kernel function, and model selection (parameters selection) of SVM.2.1 OVERVIEW OF SVMSVMs are set of related supervised learning methods used for classification and regression [2]. They belong to a family of generalized linear classification. A special property of SVM is , SVM simultaneously minimize the empiricalclassification error and maximize the geometric margin. So SVM called Maximum Margin Classifiers. SVM is based on the Structural risk Minimization (SRM). SVM map input vector to a higher dimensional space where a maximal separating hyperplane is constructed. Two parallel hyperplanes are constructed on each side of the hyperplane that separate the data. The separating hyperplane is the hyperplane that maximize the distance between the two parallel hyperplanes. An assumption is made that the larger the margin or distance between these parallel hyperplanes the better the generalization error of the classifier will be [2].We consider data points of the form{(x 1,y 1),(x 2,y 2),(x 3,y 3),(x 4,y 4)……….,(x n , y n )}.Where y n =1 / -1 , a constant denoting the class towhich that point xn belongs. n = number ofsample. Each x n is p-dimensional real vector. Thescaling is important to guard against variable(attributes) with larger varience. We can view thisTraining data , by means of the dividing (orseperating) hyperplane , which takesw . x + b = o ----- (1)Where b is scalar and w is p-dimensional Vector.The vector w points perpendicular to the separatinghyperplane . Adding the offset parameter b allowsus to increase the margin. Absent of b, thehyperplane is forsed to pass through the origin ,restricting the solution. As we are interesting in themaximum margin , we are interested SVM and theparallel hyperplanes. Parallel hyperplanes can be described by equationw.x + b = 1w.x + b = -1 If the training data are linearly separable, we can select these hyperplanes so that there are no points between them and then try to maximize their distance. By geometry, We find the distancebetween the hyperplane is 2 / │w │. So we want to minimize │w │. To excite data points, we need to ensure that for all I either w. x i – b ≥ 1 or w. x i – b ≤ -1This can be written asy i ( w. x i – b) ≥1 , 1 ≤i ≤ n ------(2) Figure.1 Maximum margin hyperplanes for aSVM trained with samples from two classesSamples along the hyperplanes are calledSupport Vectors (SVs). A separating hyperplanewith the largest margin defined by M = 2 / │w │that is specifies support vectors means trainingdata points closets to it. Which satisfy?y j [w T . x j + b] = 1 , i =1 -----(3)Optimal Canonical Hyperplane (OCH) is acanonical Hyperplane having a maximum margin.For all the data, OCH should satisfy the followingconstraintsy i [w T . x i + b] ≥1 ; i =1,2…l ------(4)Where l is Number of Training data point. In order to find the optimal separating hyperplane having a maximul margin, A learning macine should minimize ║w ║2 subject to the inequality constraintsy i [w T. x i + b] ≥ 1 ; i =1,2…….l This optimization problem solved by the saddlepoints of the Lagrange’s Function l L P = L (w, b, α) = 1/2║w ║2 -∑ αi (y i (w Tx i + b )-1) i=1l= 1/2 w T w -∑ αi (y i (w T x i + b )-1) ---(5)i=1Where αi is a Lagranges multiplier .The search for an optimal saddle points ( w 0, b 0, α0 ) is necessary because Lagranges must be minimized with respect to w and b and has to be maximized with respect to nonnegative αi (αi ≥ 0). This problem can besolved either in primal form (which is the form ofw & b) or in a dual form (which is the form of αi).Equation number (4) and (5) are convex and KKTconditions, which are necessary and sufficientconditions for a maximum of equation (4).Partially differentiate equation (5) with respect tosaddle points ( w 0, b 0, α0 ).∂L / ∂w 0 = 0li .e w 0 = ∑ αi y i x i -----------(6)i =1And ∂L / ∂b 0 = 0li .e ∑ αi y i = 0 -----------(7)i =1Substituting equation (6) and (7) in equation (5).We change the primal form into dual form.lL d (α) = ∑ αi - 1/2 ∑ αi αj y i y j x i T x j -------(8)i =1In order to find the optimal hyperplane, a dual lagrangian (L d ) has to be maximized with respect to nonnegative αi (i .e. αi must be in thenonnegative quadrant) and with respect to the equality constraints as followαi ≥ 0 , i = 1,2…...ll∑ αi y i = 0i =1Note that the dual Lagrangian L d (α) is expressed in terms of training data and depends only on the scalar products of input patterns (x i T x j ).More detailed information on SVM can be found inReference no.[1]&[2]. 2.2 KERNEL SELECTION OF SVMTraining vectors x i are mapped into a higher (may be infinite) dimensional space by the function Ф. Then SVM finds a linear separatinghyperplane with the maximal margin in this higherdimension space .C > 0 is the penality parameter of the error term. Furthermore, K(x i , x j ) ≡ Ф(x i )T Ф(x j ) is called the kernel function[2]. There are many kernel functions in SVM, so how to select a good kernel function is also a research issue.However, for general purposes, there are some popular kernel functions [2] & [3]: • Linear kernel: K (x i , x j ) = x i T x j .• Polynomial kernel:K (x i , x j ) = (γ x i T x j + r)d , γ > 0• RBF kernel : K (x i , x j ) = exp(-γ ║x i - x j ║2) , γ > 0 • Sigmoid kernel: K (x i , x j ) = tanh(γ x i T x j + r) Here, γ, r and d are kernel parameters. In these popular kernel functions, RBF is the main kernel function because of following reasons [2]: 1. The RBF kernel nonlinearly maps samples into a higher dimensional space unlike to linear kernel. 2. The RBF kernel has less hyperparameters than the polynomial kernel. 3. The RBF kernel has less numerical difficulties. 2.3 MODEL SELECTION OF SVMModel selection is also an important issue in SVM. Recently, SVM have shown goodperformance in data classification. Its success depends on the tuning of several parameters which affect the generalization error. We often call this parameter tuning procedure as the model selection. If you use the linear SVM, you only need to tune the cost parameter C. Unfortunately , linear SVM are often applied to linearly separable problems.Many problems are non-linearly separable. For example, Satellite data and Shuttle data are not linearly separable. Therefore, we often apply nonlinear kernel to solve classification problems, so we need to select the cost parameter (C) and kernel parameters (γ, d) [4] & [5].We usually use the grid-search method in cross validation to select the best parameter set. Then apply this parameter set to the training dataset and then get the classifier. After that, use the classifier to classify the testing dataset to get the generalization accuracy.3.INTRODUCTION OF ROUGH SETRough set is a new mathematic tool to deal with un-integrality and uncertain knowledge. It can effectively .analyze and deal with all kinds of fuzzy, conflicting and incomplete information, and finds out the connotative knowledge from it, and reveals its underlying rules. It was first put forward by Z.Pawlak, a Polish mathematician, in 1982. In recent years, rough set theory is widely emphasized for the application in the fields of data mining and artificial intelligence.3.1THE BASIC DEFINITIONS OF ROUGHSETLet S be an information system formed of 4 elementsS = (U, Q, V, f) whereU - is a finite set of objectsQ - is a finite set of attributesV- is a finite set of values of the attributesf- is the information function so that:f : U × Q - V.Let P be a subset of Q, P ⊆ Q, i.e. a subset of attributes. The indiscernibility relation noted by IND(P) is a relation defined as followsIND(P) = {< x, y > ∈ U × U: f(x, a) = f(y, a), for all a ∈ P}If < x, y > ∈ IND(P), then we can say that x and y are indiscernible for the subset of P attributes. U/IND(P) indicate the object sets that are indiscernible for the subset of P attributes.U / IND(P) = { U1, U2, …….U m }Where U i∈ U, i = 1 to m is a set of indiscernible objects for the subset of P attributes and Ui ∩ Uj = Ф, i ,j = 1to m and i≠ j. Ui can be also called the equivalency class for the indiscernibility relation. For X ⊆ U and P inferior approximation P1 and superior approximation P1 are defined as followsP1(X) = U{Y ∈ U/ IND(P): Y ⊆ Xl}P1(X= U{Y ∈ U / INE(P): Y ∩ X ≠Ф }Rough Set Theory is successfully used in feature selection and is based on finding a reduct from the original set of attributes. Data mining algorithms will not run on the original set of attributes, but on this reduct that will be equivalent with the original set. The set of attributes Q from the informational system S = (U, Q, V, f) can be divided into two subsets: C and D, so that C ⊂Q, D ⊂ Q, C ∩ D =Ф. Subset C will contain the attributes of condition, while subset D those of decision. Equivalency classes U/IND(C) and U/IND(D) are called condition classes and decision classesThe degree of dependency of the set of attributes of decision D as compared to the set of attributes of condition C is marked with γc (D) and is defined byPOS C (D) contains the objects from U which can be classified as belonging to one of the classes of equivalency U/IND(D), using only the attributes in C. if γc (D) = 1 then C determines D functionally. Data set U is called consistent if γc (D) = 1. POS C(D) is called the positive region of decision classes U/IND(D), bearing in mind the attributes of condition from C.Subset R ⊂ C is a D-reduct of C if POS R (D) = POS C(D) and R has no R' subset, R' ⊂ R so that POS R’.(D) = POS R(D) . Namely, a reduct is a minimal set of attributes that maintains the positive region of decision classes U/IND(D) bearing in mind the attributes of condition from C. Each reduct has the property that no attribute can be extracted from it without modifying the relation of indiscernibility. For the set of attributes C there might exist several reducts.The set of attributes that belongs to the intersection of all reducts of C set is called the core of C.An attribute a is indispensable for C if POS C (D) ≠ POS C[a] (D). The core of C is the union of all indispensable attributes in C. The core has two equivalent definitions. More detailed information on RSES can be found in .[1]&[2].4RESULTS OF EXPERIMENTSThe classification experiments are conducted on different data like Heart data, Diabetes data, Satellite data and Shuttle data. These data taken from/~mlearn/MLRepository.html and RSES data sets . In these experiments, we done both method on different data set. Firstly, Use LIBSVM with different kernel linear , polinomial , sigmoid and RBF[5]. RBF kernel is employed. Accordingly, there are two parameters, the RBF kernel parameter γ and the cost parameter C, to be set. Table 1 lists the main characteristics of the three datasets used in the experiments. All three data sets, diabetes , heart, and satellite, are from the machine learning repository collection. In these experiments, 5-fold cross validation is conducted to determine the best value of different parameter C and γ .The combinations of (C, γ) is the most appropriate for the given data classification problem with respect to prediction accuracy. The value of (C , γ) for all data set are shown in Table 1. Second, RSES Tool set is used for data classification with all data set using different classifier technique as Rule Based classifier, Rule Based classifier with Discretization, K-NN classifier and LTF (Local Transfer Function) Classifier. The hardware platform used in the experiments is a workstation with Pentium-IV-1GHz CPU, 256MB RAM, and the Windows XP(using MS-DOS Prompt).The following three tables represent the different experiments results. Table 1 shows the best value of different RBF parameter value (C , γ) and cross validation rate with 5-fold cross validation using grid search method[5]&[6]. . Table 2 shows the Total execution time for all data to predict the accuracy in seconds.Table 1Fig. 2, 3 shows, Accuracy comparison of Diabetes data Set after taking different training set and all testing set for both technique (SVM & RSES) using RBF kernel function for SVM and Rule Base Classifier for RSES.Fig :2 Accuracy of Heart data with SVM & RSES Applicat-ions TrainingdataTestingdataBest c and g withfive foldCrossvalidationrateC γDiabetes data500 200211=20482- 7=.007812575.6HeartData200 7025=32 2-7 =.007812582.5Satellite Data4435 200021=2 21=291.725ShuttleData435014435 215=3276821=2 99.92Applications Total Execution Time toPredictSVM RSES Heart data71 14Diabetes data22 7. 5Satellite data74749 85 Shuttle Data252132.1 220Fig: 3 Accuracy of Diabetes data with SVM & RSESTable 3: Compare with Rough Set Classifiers5 CONCLUSIONIn this paper, we have shown the comparative results using different kernel functions. Fig 2 and3 shows the comparative results of different datasamples using different kernels linear,polynomial, sigmoid and RBF. The experimentresults are encouraging .It can be seen that thechoice of kernel function and best value ofparameters for particular kernel is critical for agiven amount of data. Fig 3 shows that the bestkernel is RBF for infinite data and multi class.REFERENCES:[1] Boser, B. E., I. Guyon, and V. Vapnik (1992).A training algorithm for optimal marginclassifiers . In Proceedings of the FifthAnnual Workshop on ComputationalLearning Theory, pages. 144 -152. ACM Press 1992.[2] V. Vapnik. The Nature of Statistical Learning Theory. NY: Springer-Verlag. 1995.[3] Chih-Wei Hsu, Chih-Chung Chang, and Chih- Jen Lin. “A Practical Guide to Support Vector Classification” . Deptt of Computer Sci.National Taiwan Uni, Taipei, 106, Taiwan.tw/~cjlin 2007 [4] C.-W. Hsu and C. J. Lin. A comparison ofmethods for multi-class support vectormachines. IEEE Transactions on NeuralNetworks, 13(2):415-425, 2002.[5] Chang, C.-C. and C. J. Lin (2001). LIBSVM:a library for support vector machines..tw/~cjlin/libsvm . [6] Li Maokuan, Cheng Yusheng, Zhao Honghai ”Unlabeleddata classification via SVM and k- means Clustering”. Proceeding of theInternational Conference on ComputerGraphics, Image andVisualization (CGIV04), 2004 IEEE.[7] Z. Pawlak, Rough sets and intelligent dataanalysis, Information Sciences 147 (2002) 1– 12.[8] RSES 2.2 User’s Guide Warsaw University .pl/»rses ,January 19, 2005[9] Eva Kovacs, Losif Ignat, “Reduct Equivalent Rule Induction Based On Rough Set Theory”, Technical University ofCluj-Napoca.[9] RSES Home page.pl/»rsesApplications Trainingdata TestingdataFeature No. OfClassesUsingSVM(withRBFkernel)Using RSES with Different classifierRuleBasedClassifierRule BasedClassifierwithDiscretizationK-NNClassifierLTFClassifierHeart data 200 70 13 2 82.8571 82.9 81.4 75.7 44.3 Diabetesdata500 200 8 2 80.5 67.8 67.5 70.0 78.0Satellitedata4435 2000 36 7 91.8 87.5 89.43 90.4 89.7 Shuttle Data 43500 14435 9 7 99.9241 94.5 97.43 94.3 99.8BIOGRAPHY:Mr Durgesh K. Sriavastava received the degree in Information & Technology (IT) from MIET, Meerut, UP, INDIA in 2006. He was a research student of Birla Institute of Technology (BIT), Mesra, Ranchi, Jharkhand, INDIA) in 2008. Currently, he is an Assistant Professor (AP) at BRCM CET, Bahal, Bhiwani, Haryana, INDIA. His interests are in Software engineering & modeling and design, Machine Learning.Mrs Lekha Bhambhureceived the degree in Computer Science & Engineering from BRCM CET, Bahal, Bhiwani, Haryana, INDIA. she was a research student of CDLU, Sirsa, Haryana, INDIA. Currently, she is an Assistant Professor (AP) at BRCM CET, Bahal, Bhiwani, Haryana, INDIA. Her interests are in Operating System, Software engineering.。
外文翻译
附录Introduction to basic machiningMechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. There are:(1) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the work piece and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions whichcontinuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.(3) The stability of the machine tool. Under some combinations of cutting conditions: work piece size , method of clamping, and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and work piece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the work piece surface and short pitch undulations on the transient machined surface.(4) The effectiveness of removing sward. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (sward) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps ate taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking beside a looking unattractive, often results in a poorer surface finishing,(5) The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable than to satisfactorily fulfill their function. In some cases, tit is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt, chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, many require some special surface treatment to provide uniformity of appearance.Surface finishing many sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one par to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a ‘fitter’ in the literal sense. It is obvious that the two parts wo uld have to remain together, and in the event of one having to be replaced, the fitting would have to be done all over again. I n these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used ‘off the shelf’ to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, ‘fiddling’ operation, and it benefits the customer in the event of the need to replace worn parts.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so it will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools becomeworn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For example, a part might be made 6 in. long with a variation allowed of 0.003(three thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size are derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is shown I only one direction from the nominal size. Unilateral tolerancing allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size, it is known as a bilateral tolerance (plus and minus).Bilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions are shown. Thus, the tolerance is the difference between these two dimensions.Introduction of Machining of:Machining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported work piece.Low setup cost for small quantities. Machining has two applications in manufacturing. For casting, forging, and pressworking, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may be produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining, to start with nearly any form of raw material, so long as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore, machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or pressworking if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced I high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in pressworked parts may be machined following the pressworking operations.外文文献翻译机械加工基础简介表面粗糙度的技术在已经进行机械加工过的表面，有五种基本的影响其表面粗糙度的技术。
4P营销策略和营销渠道外文文献翻译2014年译文3000多字
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外文文献翻译格式一般需包括以下内容：
1. 文献翻译的题目：对外文文献的标题进行翻译，并在翻译后的题目前加上“外文文献翻译：”。
2. 文献的出处：包括外文文献的作者名称、文献标题、原文出版信息等。
3. 翻译的正文：按照文章的段落，将外文文献逐段翻译成中文。
在翻译的文本前后加上序号，以示区分。
4. 翻译的语言风格：外文文献翻译应注重语言风格的保持。
翻译时要根据文章的风格，选择适当的中文表达方式，保持原文的句子结构和词汇用法。
5. 原文和译文对照：将原文和译文对照排列，方便读者对照阅读。
可以将原文和译文分别排列在左右两栏中，或者将原文和译文分别放在不同的页面上，便于对照阅读。
6. 翻译中的注释：如果有部分内容翻译困难或有待解释的地方，在翻译文中添加注释。
注释的格式一般为在译文后面加上方括号，括号内的文字为注释内容。
7. 译者的信息：在文献翻译末尾一般会加上译者的姓名，并注明译者的专业领域或者工作单位。
总之，外文文献翻译格式需要将原文翻译成中文，保持原文的结构和风格，并加上适当的注释和对照，方便读者阅读和理解。
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毕业设计外文资料翻译题 目 钢结构栓焊节点在火中的行为 学 院 土木建筑学院 专 业 土木工程 班 级 土木1008班 学 生 王召博 学 号 20100622273 指导教师朱春梅 二〇一四年 二月二十四日题，连接管交底。
不严应采用备，在卷相互中资料继电保写重要备进行问题，、电力保护体配料试卷卷保料试卷试技钢结构栓焊节点在火中的行为胡 军， 姚 斌， 厉培德中国科技大学火灾科学国家重点实验室摘 要 为了研究钢结构栓焊节点在火中的行为，进行了一系列实验。
就火灾模型和荷载比对接头性能的影响，破坏特征和暴露于火灾的接头断裂模式进行了研究。
实验结果表明，火灾模型以及暴露于火灾的接头上的温度分布对结果影响很大。
温度缓慢上升，可以使接头温度分布更加均匀。
荷载比下降会提高节点的抗火性能。
此外，用ANSYS 软件建立了一个非常详细的三维（3D ）有限元模型（FEM ）用以预测的栓焊边节点在火灾的行为。
预测结果和实验结果表明，有限元法对于这类节点在火中的行为预测结果处于可接受的准确度之中。
关键词 钢筋接头；火；实验研究；有限元模型中图分类号：TU352. 5 文档代码：A 文章编号：1005-9113( 2011) 01-0089-07梁柱连接节点在室温和高温下的结构行为被认为是具有重要意义的影响。
全尺寸火灾试验表明，从损坏的结构确认接头在火中由于其重新分配力量，对结构构件的生存时间是一个相当大的影响。
因此有必要通过估计局部变形和诱导应力来准确的评估连接节点的能力。
作为最可靠的方法，实验可以准确地描述暴露在火中的节点的行为。
然而，在许多情况下是不可行的实验或过于昂贵的行为。
同时，他们还总是受限于几何数量和机械参数研究。
近年来，有限元法已就实验室中难以进行的解决的现实世界的问题给出方案获得了相当的认可。
作为一个可靠的工具来模拟所有相关参数的影响，有限元法给出了一个有吸引力的手段来研究梁柱节点的更详细的实验通常会允许。
在过去的几年里，大量的研究已经在不同类型的梁进行了实验和分析方法，了解他们的行为节点在环境温度和升高的温度。
1976年CTICM 对钢节点数的火灾试验采用的高温高强度螺栓的性能研究结果，并没有迹象显示节点的性能。
1982年两个由英国钢铁实验得出节点在火灾遭受重大的变形。
通过试验证明了Lawson 的结论，得出这些节点在火中的表现，节点可以在火焰条件下的持续升温。
结合Al-Jabri 研究参数的影响。
这些测试提供了对节点相关的各种理论研究的有用数据。
有限元建模研究联合行为的使用开始于1970年代初，随着计算机在解决结构问题中的应用变得明显。
近年来，许多功能强大的有限元软件如ANSYS ，ABAQUS ，LUSAS ，LAGAMINE 已成为市售。
他们有能力解决范围广泛工程问题的有效和准确的方式。
虽然大量的研究已经在室温下进行不同的节点，很少研究工、管路敷设技术通过管线敷设技术不仅可以解层配置不规范高中资料试卷问题，而要加强看护关于管路高中资料试卷连接理高中资料试卷弯扁度固定盒位置保管线敷设技术中包含线槽、管架等多，为解决高中语文电气课件中管壁薄、不严等问题，合理利用管线敷设技术。
敷设完毕，要进行检查和检测处理、电气课件中调试高中资料试卷电气设备，在安装过程中装结束后进行高中资料试卷调整试验检查所有设备高中资料试卷相互作用与系，根据生产工艺高中资料试卷要求气设备进行空载与带负荷下高中资料试过度工作下都可以正常工作；对于继电行整核对定值，审核与校对图纸，编设备高中资料试卷试验方案以及系统案；对整套启动过程中高中资料试卷电进行调试工作并且进行过关运行高中试验报告与相关技术资料，并且了高中资料试卷布置情况与有关高中气系统接线等情况，然后根据规范，制定设备调试高中资料试卷方案气设备调试高中资料试卷技术电力保护装置调，电力保护高中资料试卷配置技术是指在进行继电保护高中资料试卷总体配置，并且尽可能地缩小故障高中资料试范围，或者对某些异常高中资料试卷工护装置动作，并且拒绝动作，来避免中资料试卷突然停机。
因此，电力高试卷保护装置调试技术，要求电力保护切除从而采用高中资料试卷主要作已经进行了到目前为止模型由于大量的参数需要考虑在火灾不同类型节点的行为。
刘对模型在火灾的节点行为的第一次尝试，建立有限元模型，模拟了FEAST ，在火灾中各种接头类型。
三维有限元模型已被EI houssieny 等人开发的模拟在室温和高温下最近扩展的端板的响应，Rahman 用ANSYS 研究火灾的板翅结构接头的行为。
在升高的温度下Al JabriABAQUS 对平端板棒材节点的行为。
上述有限元模型计算结果与实验结果吻合良好。
栓焊边节点被归类为“rigid”节点与梁翼缘焊接到柱，即梁腹板法兰螺栓柱翼缘的板翅式刚性节点。
由于制作方便，安装迅速他们被广泛用于支撑多层钢结构建筑。
虽然王已经报道了这类联合实验，其研究主要集中在单一荷载比ISO 火曲线的联合响应。
在本文中，介绍了针对H 型钢进行了四实寸实验，无论是火灾模型和负荷率每一个试样均不同，针对性调查火灾模型和负荷率对接头性能的影响，并记录暴露于火灾的接头断裂模式的破坏特征。
商业有限元分析软件ANSYS 进行模拟测试的两个标本使用三维模型的行为。
一个可靠的有限元模型的建立是为了测试结果的补充，对一个广泛的参数可以进行分析，以验证模型来预测在接下来的研究中的暴露在火中的节点的行为。
这是很难在实验室条件下实现。
1 实验研究1.1 实验装置和仪器所有测试都是在填埋气炉进行的结构防火测试。
手绘图和火灾试验布置图分别显示在图.1和图.2。
图.1火灾试验布置示意通过管线敷用管线敷设技术。
线缆敷设原则：在处，当不同电压回路交叉时，应采用金进行隔开处理；同一线槽内，强电回和检测处理。
对全部高中资料试卷电气设备，在安装过程中以及安装结束后进行高中卷相互作用与相互关系，根据生产工艺进行过关运行高中资料试卷技术指导试过程中高中资料试卷技术问题，作人员，需要在事前掌握图纸资料、设备料，并且了解现场设备高中资料试卷与有关高中资料试卷电气系统接线等中资料试卷方案。
力保护装置调试技术，电力保护高中资术，要求电力保护装置做到准确灵活差动保护装置高中资料试卷调试技术是电机一变压器组在发生内部故障时，需试卷主要保护装置。
图.2火灾实验布置照片如图2所示，该炉由两部分组成，分别固定在两个活动板。
所以在安装试样过程中炉可方便的打开或关闭。
ISO834标准火灾和BFD 自然火灾实验所选择的公式为（1）和（2），发现火灾模型节点在火灾中的的影响变化。
T － T 0 = 345lg( 8t + 1) （1）T = T 0 + T max e － ( lnt － lnt max ) 2 / S C （2）T 0（℃）: 环境温度； T max （℃ ）：最大温度（高于T 0）； t max （min ）：到达T max 的时间；S C 不随曲线变化而变化。
方程（2）在本研究中，T 0，T max ，S C ，t max 分别为20℃，780℃，1.85,30min ，两个实验对应的曲线如图.3图.3火灾模式曲线一线槽内，强电回路须同时切断习题线缆敷设完毕，要进行检查和检测处理掌握图纸资料、设备制造厂家出具高中试卷试验报告与相关技术资料，并且了设备高中资料试卷布置情况与有关高发生内部故障时，需要进行外部电源高试卷切除从而采用高中资料试卷主要置。
测试过程中，一个有心力被应用在由液压千斤顶来模拟柱内力的联合柱。
另一个有心力对梁模拟弯曲载荷梁承受练习。
两个液压千斤顶连接到反应框架并由一个压力控制泵的动力。
为了模拟节点的实际情况，两边作用力在整个测试过程中保持不变。
两个位移传感器被用来测量束的垂直偏转从而获得与火的温度增加关节的旋转变化。
两个负载开关，安装在液压千斤顶进行控制，应用于节点的力量。
两个铠装热电偶位于炉内测量炉的温度，它也被用于控制的增加炉内温度。
其他13个铠装热电偶嵌入在接头不同位置分别测量节点增加的温度。
铠装热电偶的安排如图.4所示。
所有的K 型热电偶均为镍铬和镍硅合金。
图.4热电偶布置实验过程中，在关闭填埋气炉之前建立试样。
然后设计载荷施加在柱上分别为梁的顶部法兰上，开始加热。
炉内温度的自动升高到预先设计的温度时间曲线上。
温度在负荷试样在测试过程中保持恒定，最后，在节点出现故障时关闭炉火。
所有的数据被收集并通过一个数据采集器自动记录、1.2 Specimen Details 测试由一个HW 175×175×7. 5×11柱高度为2.11 m 的标本和一个HN248×124×5×8悬臂梁长1.0米的标本组成。
悬臂梁的一侧被连接到翼缘，栓焊边节点位于高1.41m 的位置。
两个M20级10.9的螺栓拧紧到403N·m 的扭矩板上，按照相关规定，确保试样的细节，如图.5所示。
所有的四组测试在对试样125 kN 载荷水平的塔顶进行。
应用与不同的荷载比R ，它的定义是，在一般情况下，由于施加的载荷在火焰极限状态和负载能力，该构加强看护关于管路高中资料试卷连接管度工作下都可以正常工作；对于继电保试高中资料试卷方案。
，并且尽可能地缩小故障高中资料试卷件可以采取20℃之间的比。
在这项研究中，两个荷载水平0.28和0.36分别采用。
节点测试详情见表.1图.5试样细节1.3 整个节点的温度分布当暴露在火中，无论是机械特性和钢的热性能会受到升高温度的影响。
其结果是，整个节点温度分布是影响节点的行为的重要因素之一。
从试验中获得这两种情况下的温度分布，如图.6（a ）和（b ）所示。
节点在用于ISO 情况下的温度上升速度比的BFD 情况稍微更迅速。
同时，对于BFD 情况下，节点具有更均匀的温度分布为较慢的炉内温度上升的过程。
在一般情况下，柱的温度为比梁和板的高一点。
同时切断习题电源，线缆敷设完毕，要进行检查和检测处理。
造厂家出具高中资料试卷试验报告与相关技术资料，并且了解现场设备高中资料试卷布置情况与有关高中资料试卷电气系统接线等情况，然后根据规范与规程规定，制定设备调试高中资料试卷方案。
进行外部电源高中资料试卷切除从而采用高中资料试卷主要保护装置。
如图.6（a ）ISO 如图.6（b ）BFD 2结论1) 温度的增加以及栓焊节点的温度分布对火灾模型有很大的影响。
增加较慢射速的温度会导致温度和节点温度分布更加均匀增长缓慢。
这将有助于提高节点的抗火性能。
2) 荷载比的下降会导致相同的火灾条件下的有限温度的增加。
3)暴露在火中时，主要模式梁的下翼缘外部栓焊节点局部弯曲变形并在节点区柱中有明显的失真。
4) 对比实验结果与预测结果表明，有限元法具有测该类型节点的火灾行为的对全部济南大学毕业设计外文资料翻译参考文献：［1］Al-Jabri K S，Lennon T，Burgess I W，等。