电子信息工程专业客户信息管理系统大学毕业论文外文文献翻译及原文

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电子商务信息安全中英文对照外文翻译文献

电子商务信息安全中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：E-commerce Information Security ProblemsⅠ. IntroductionE-commerce (E-Business) is in open networks, including between enterprises (B2B), business and consumers (B2C) commercial transactions, compared with the traditional business model, e-commerce with efficient, convenient, covered wide range of characteristics and benefits. However, e-commerce open this Internet-based data exchange is great its security vulnerabilities, security is a core e-commerce development constraints and key issues.In this paper, the basic ideas and principles of systems engineering, analyzes the current security threats facing e-commerce, in this based on security technology from the perspective of development trend of e-commerce.Ⅱ. E-commerce modelModern e-commerce technology has focused on the establishment and operation of the network of stores. Network in the department stores and real stores no distinction between structure and function, differences in their function and structure to achieve these methods and the way business operate.Web store from the front view is a special kind of WEB server. WEB site of modern multimedia support and a good interactive feature as the basis for the establishment of this virtual store, so customers can, as in a real supermarket pushing a shopping cart to select goods, and finally in the checkout check out. These online stores also constitute the three pillars of software: catalog, shopping cart and customer checkout. Customers use an electronic currency and transaction must store customers and stores are safe and reliable.Behind the store in the network, enterprises must first have a product storage warehouse and administration; second network to sell products by mail or other delivery channels to customers hands; Third, enterprises should also be responsible for product after-sales service, This service may be through networks, may not. Internet transactions are usually a first Pay the bill and getting goods shopping. For customers, convenience is that the goods purchased will be directly delivered to their home, but hard to feel assured that the goods can not be confirmed until the handsreach into their own hands, what it is.Therefore, the credibility of the store network and service quality is actually the key to the success of e-commerce.Ⅲ.the key to development of electronic commerceE-commerce in the telecommunications network to develop. Therefore, the advanced computer network infrastructure and telecommunications policy easing the development of electronic commerce has become a prerequisite. Currently, telecom services, high prices, limited bandwidth, the service is not timely or not reliable and so the development of e-commerce has become a constraint. Speed up the construction of telecommunications infrastructure, to break the telecommunications market monopoly, introduce competition mechanism to ensure fair competition in the telecommunications business, to promote networking, ensure to provide users with low-cost, high-speed, reliable communications services is a good construction target network environment, but also all of the world common task.E-commerce the most prominent problem is to solve the on-line shopping, trading and clearing of security issues, including the establishment of e-commerce trust between all the main issues, namely the establishment of safety certification system (CA) issues; choose safety standards (such as SET , SSL, PKI, etc.) problems; using encryption and decryption method and encryption strength problems. Establishment of security authentication system which is the key.Online trading and traditional face to face or written transactions in different ways, it is transmitted through the network business information and trade activities. The security of online transactions means:Validity: the validity of the contract to ensure online transactions, to prevent system failure, computer viruses, hacker attacks.Confidentiality: the content of the transaction, both transactions account, the password is not recognized by others and stealing.Integrity: to prevent the formation of unilateral transaction information and modify.Therefore, the e-commerce security system should include: secure and reliable communications network to ensure reliable data transmission integrity, prevent viruses, hackers; electronic signatures and other authentication systems; complete data encryption system and so on.Ⅳ.e-commerce security issues facingAs e-commerce network is the computer-based, it inevitably faces a number of security issues.(1) Information leakPerformance in e-commerce for the leakage of business secrets, including two aspects: the parties are dealing transactions by third parties to steal the contents; transaction to the other party to provide documents used illegal use by third parties.(2) AlteredE-commerce information for business performance in the authenticity and integrity issues. Electronic transaction information in the network transmission process may be others to illegally modify, delete or re-changed, so that information about its authenticity and integrity.(3) IdentificationWithout identification, third-party transactions is likely to fake the identity of parties to a deal breaker, damage the reputation of being counterfeit or stolen by one party to the transaction fake results and so on, for identification, the transaction between the two sides can prevent suspicion situation.(4) Computer virusesComputer virus appeared 10 years, a variety of new virus and its variants rapidly increasing, the emergence of the Internet for the spread of the virus has provided the best medium. Many new viruses directly using the network as its transmission, as well as many viruses spread faster through dried networks, frequently causing billions of dollars in economic losses.(5) HackerWith the spread of a variety of application tools, hackers have been popular, and are not in the past; non-computer expert can not be a hacker. Have kicked Yahoo's mafia boy did not receive any special training, only a few attacks to the users to download software and learn how to use the Internet on a big dry.Ⅴ.e-commerce security and safety factorsEnterprise application security is the most worried about e-commerce, and how to protect the security of e-commerce activities, will remain the core of e-commerce research. As a secure e-commerce system, we must first have a safe, reliable communication network, to ensure that transaction information secure and rapidtransmission; second database server to ensure absolute security against hackers break into networks to steal information. E-commerce security technologies include encryption, authentication technology and e-commerce security protocols, firewall technology.(A), encryption technologyTo ensure the security of data and transactions to prevent fraud, to confirm the true identity of transaction parties, e-commerce to adopt encryption technology, encryption technology is through the use of code or password to protect data security. For encrypted data is called plaintext, specifically through the role of a encryption algorithm, the conversion into cipher text, we will express this change as the cipher text is called encryption, the cipher text by the decryption algorithm to form a clear role in the output of this a process known as decryption. Encryption algorithm known as the key parameters used. The longer the key, the key space is large, traverse the key space the more time spent, the less likely cracked.Encryption technology can be divided into two categories: symmetric encryption and asymmetric encryption. Symmetric encryption to the data encryption standard DES (Data Encryption Standard) algorithm is represented. Asymmetric encryption is usually RSA (Rivets Shamir Aleman) algorithm is represented.(B), authenticationCommonly used security authentication technologies: digital signatures, digital certificates, digital time stamp, CA security authentication technology.(C), hacker protection technologyCurrently, hackers have become the biggest e-commerce security threats, thus preventing hacking network security technology has become the main content, by governments and industry are highly valued. Hacking techniques include buffer overflow attacks, Trojans, port scans, IP fraud, network monitoring, password attacks, and denial of service Dos attacks. At present, people have made many effective anti-hacker technologies, including firewalls, intrusion detection, and network security evaluation techniques.Ⅵ.the future security of e-commerceIncreasingly severe security problems, are growing threat to national and global economic security, governments have been based on efforts in the following areas: (1) Strengthen the legislation, refer to the advanced countries have effective legislation, innovative, e-commerce and improve the protection of the laws againstcyber-crime security system.(2) Establishment of relevant institutions, to take practical measures to combat cyber crime. Development of the law, the implementing agencies should also be used for its relevant laws, which must establish an independent oversight body, such as the executing agency to implement the law.(3) Increase investment in network security technology; improve the level of network security technology. E-commerce security law is the prerequisite and basis for development and secure e-commerce security technology is a means of protection. There are many security issues are technical reasons, it should increase the technology resources, and continuously push forward the development of old technologies and developing new security technology.(4) To encourage enterprises to protect themselves against Internet crime against. To avoid attack, companies can not hold things to chance, must attach great importance to system vulnerabilities, in time to find security holes to install the operating system and server patches, and network security detection equipment should be used regularly scan the network monitoring, develop a set of complete security protection system to enable enterprises to form a system and combined with the comprehensive protection system.(5) To strengthen international cooperation to strengthen global efforts to combat cyber crime. As e-commerce knows no borders, no geographical, it is a completely open area, so the action against cyber crime e-commerce will also be global. This will require Governments to strengthen cooperation, can not have "the saying which goes, regardless of others, cream tile" misconception.(6) To strengthen the network of national safety education, pay attention to the cultivation of outstanding computer.Ⅶ. ConclusionE-commerce in China has developed rapidly in recent years, but the security has not yet established. This has an impact on the development of electronic commerce as a barrier.To this end, we must accelerate the construction of the e-commerce security systems. This will be a comprehensive, systematic project involving the whole society. Specifically, we want legal recognition of electronic communications records of the effectiveness of legal protection for electronic commerce; we should strengthen the research on electronic signatures, to protect e-commerce technology; we need to build e-commerce authentication system as soon as possible, to organize protection for electronic commerce. Moreover, for e-commerce features without borders, we shouldalso strengthen international cooperation, so that e-commerce truly plays its role. Only in this way, we can adapt to the timesPromoting China's economic development; also the only way we can in the economic globalization today, to participate in international competition, and thus gain a competitive advantage.Source: Michael Hecker, Tharam S. Dillon, and Elizabeth Chang IEEE Internet Computing prentice hall publishing, 2002电子商务中的信息安全问题一、引言电子商务（E-Business）是发生在开放网络上的包括企业之间（B2B）、企业和消费者之间（B2C）的商业交易，与传统商务模式相比，电子商务具有高效、便捷、覆盖范围广等特点和优点。

电子信息工程专业毕业论文外文翻译中英文对照翻译

本科毕业设计（论文）中英文对照翻译院（系部）电气工程与自动化专业名称电子信息工程年级班级 04级7班学生姓名指导老师Infrared Remote Control SystemAbstractRed outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique,drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point SSL, be free from electromagnetism thousand Raos etc.characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage.Along with red outside the data deliver a technique more and more mature, the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application.The purpose that design this system is transmit cu stomer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplishcustomer’s o peration demand.Keywords:Infrare dray；Code；Decoding；LM386；Redoutside transceiver1 Introduction1.1 research the background and significanceInfrared Data Communication Technology is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.Infrared transceiver products with low cost, small, fast transmission rate, the point-to-point transmission security, not subject to electromagnetic interference and other characteristics that can be achieved between the different products, rapid, convenient and safe exchange and transmission, In short distance wireless transmission have a very distinct advantage.Infrared transceiver products in the portable product of a great role. At present, the world's 150 million piece of equipment used infrared technology in electronic products and industrial equipment. medical equipment and other fields widely used. For example, 95% of the notebook computers on the installation of infrared transceiver interface the majority of the cell phone is also the allocation of infrared transceiver interface. With the exchange of quantitative data, infrared data communications will enable cell phone data transmission more convenient. With infrareddata transmission technology matures, perfect, low costs, Infrared Transceiver in short distance communications will be more widely applied.This chapter first describes the infrared transceiver IC design issues to the background and significance. then briefed the infrared data communications technology features and applications, and infrared transceiver product characteristics, domestic and international situation and development trend of the last under infrared remote transceiver system in practical application to establish a task of design orientation.1.2 Infrared Remote ControlTransceiver SystemInfrared remote control system is divided into single-channel and multi-channel remote control. Only a command signal transmission channel, called single-channel remote control system; with more than two instructions signal transmission channel known as a multi-channel remote control system. Relatively simple single-channel remote control, in general, only a launcher directive Key receivers and only one circuit implementation. While in the receiving circuit to add more stable memory circuits that can be activated commands to launch a number of key, so that the receiver circuit multistable memory circuit repeatedly to change the state, to realize many of the functional control, But such a state of change is the order. If we are to achieve an arbitrary control, resort to the use of multi-channel remote control system. Multi-channel remote control can be realized by the object of arbitrary multi-function remote control. As for the choice of several routes and what control methods, according to the actual situation (such as object, operational requirements and costaccounting, etc.) to decide. General infrared remote transceiver system by infrared remote control transmitter signal coding, infrared remote control signal receivers and decoders (or decoder chip MCU) and the external circuit consisting of three parts. Signal transmitter remote control code used to generate pulses of infrared emission-driven output infrared remote control signal, receiver completion of the remote control signal amplification and detection, plastic and demodulation encoding pulse. Infrared remote control coded pulse is going to obtain a continuous serial binary code, and for most of the infrared transceiver system, This serial code as micro-controller of the remote control input signals from the internal CPU completion of the remote control instruction decoder, on the other infrared remote control transceivers, the designers of electronic products, The internal micro-controller of the remote control decoder directive is not accessible. Therefore, people are using infrared encoder / decoder chip and microcontroller developed various generic infrared remote transceiver system, In various equipment infrared signals between the transceiver.Remote transceiver system generally transmitters and receivers is composed of two parts. Launchers from the general direction keys, coded instructions circuit modulation circuit, driving circuit, firing circuit of several parts. When pressed a key, the directive coding circuit, in the corresponding instructions encoded signal, the encoder signal to the carrier modulation, Driven by the power amplifier circuit after circuit fired from the field after firing instructions coded modulation signals. General receiver by the receiving circuit, the amplifier circuit, demodulation circuits, instruction decoder circuit, driving circuit, circuitimplementation of several parts. Receiving Circuit will launch vehicles have been coded modulation signal receiving instructions from, and to enlarge evacuation demodulation circuit. Demodulation circuit will have the coding modulation signal demodulation, namely, reduction of signal coding. The instruction decoder to the encoder signal decoding, Driven by the final circuit to drive the implementation of various instructions circuit to control the operation.1.3 infrared remote control transceiver product profiles1.3.1 infrared remote control transceiver product structure and typeCurrently infrared transceiver in accordance with the mode of transmission rate and can be divided into four categories : Serial mode, the highest rate of 115.2 Kbps; medium-speed model : the highest rate of 0.567 Mbps and 1.152Mbps; High-speed mode : The maximum rate of 16 Mbps.Also according to the size chip power consumption can be divided into low-power consumption and standard two categories, low-power type normally used 3 V power supply, transmission distance closer to about 0 - 30cm, which is commonly used standard 5V power supply, transmission distance away at least 1m above.1.3.2 infrared remote control transmitters of the status quo at home and abroadInfrared communication technology in the development stage and there are several infrared communication standards, between different standards for infrared equipment can not infrared communication. To have all the infrared equipment to interoperability in 1993 by more than 20 large manufacturers initiated the establishment of an Infrared Data Association (IRDA)unified the infrared communication standards , which is currently widely used in infrared data communication protocols and standards, also known as the IRDA standard.Since 1993 IRDA since the establishment of the Infrared Data Association members have developed to more than 150. IRDA standards of the industry has been widely recognized and supported. Has been developed with the infrared communications equipment have been as many as 100 species. IR module, installed capacity has reached 150 million sets. Although there is also a short distance wireless Bluetooth technology, But in infrared communication technology low cost and broad compatibility advantages, Infrared data communication in the future will still be a very long time inherent short-range wireless data communications fields play an important role.1.3.3 Infrared Transceiver product development trendIn various infrared transceiver products, although the transmission rate, transmission distance and other characteristics, But infrared transceiver products has been towards improving the transmission rate, increase the transmission distance and lower power consumption, expanding launch reception angle of development. In particular, as the technology development and maturity, the means of transmission is moving in the direction of point-to-multipoint. Therefore infrared remote control transceiver products have broader prospects for development.2 Infrared communication of knowledge2.1 infrared ray foundation knowledge2.1.1 infrared outlinedInfrared is actually a kind of electromagnetic wave. From theanalysis of various natural component of the electromagnetic wave reflected spectrum is :-ray, x-ray, ultraviolet, visible, infrared, microwave and radio wave. From the viewpoint of form, and they did not seem to, but if the wavelength in descending order, and we will find him all the only visible light spectrum of the entire 0.38 μm - 0.76μm so long little area, and adjacent to the visible light and infrared (including the far infrared, mid-infrared and near infrared foreign) accounts for the spectrum of 0.76 μm - 1000μm of a major. Which micron wavelength range also includes UV, visible, near infrared, mid-infrared and far-infrared, microwave.From the above analysis shows that infrared is a very rich spectrum resources, it currently has in production, life, military, medical, and other aspects have been widely used, such as infrared heating, medical infrared, infrared communication, infrared camera, infrared remote control, and so on. Infrared remote control is the many applications of infrared part of the current household appliances widely used in TV remote control, VCR remote control, VCD remote control, high-fidelity audio remote control, are used infra-red remote control, It allows the control of these appliances have become very easy.2.1.2 infrared propertiesInfrared lies between visible light and microwave a wave, it is with certain clinical characteristics of the wave. In the near-infrared, visible light and its adjacent, it is visible in certain characteristics, such as straight-line transmission, reflection, refraction, scattering, diffraction, can be certain objects and can be absorbed through the lens of their focusing. In the far-infrared region, owing to its neighboring microwave, it hassome characteristics of microwave, If a strong penetrating power and can run through some opaque substances. Since in any object, natural profession, regardless of whether its own luminescence (referring to visible light), as long as the temperature is above absolute zero (-273 ° C), moment will be kept around to infrared radiation. Only higher temperature of objects strong infrared radiation, low-temperature objects infrared radiation weaker. Therefore infrared feature is the greatest common in nature, it is called thermal radiation called thermal radiation. Infrared cameras, infrared night market pyroelectric infrared detectors and some other missiles aiming at is the use of this characteristic of infrared work.Infrared and visible light compared to another characteristic of a variety of colors. As the longest wavelength of visible light is a wavelength of the shortest times (780 nm-380 nm), So is called an octave. And infrared wavelength is the longest shortest wavelength of a times, and the longest wavelength infrared is the shortest wavelength of 10 times, that is, 10 octave. Therefore, if visible light can be expressed as seven colors, infrared may performance 70 colors, showing the rich colors. Infrared smoke through the good performance, which is also one of its features.Because not visible to the infrared, it has little effect on the environment. By the wave infrared rays than the long wavelength radio waves, infrared remote control will not affect the nearby radio equipment. Another wavelength of less than 1.5μm near infrared light, transparent atmosphere in the visible light transmission characteristics much better than, because it close to the visible edge of the red light, linear transmission, reflection,refraction and absorption material and the physical characteristics very similar to visible light. Therefore, it can be used with similar visible focusing lens and other optical devices. Because infrared remote control is not as remote as the radio through the barrier to control the object's ability to control, so in the design of household appliances infra-red remote control, wireless remote control as unnecessary, each set (transmitters and receivers) have different frequency or remote coding (Otherwise, wall will control or interference with neighbors household appliances), all similar products in the infrared remote control, The same can control the frequency or coding, and no remote control signal "drop." This universal infrared remote control provides a great convenience. Infrared to visible light, is very subtle and confidentiality, therefore, the security, Alert and other security devices have been widely used. Infrared remote control is simple in structure and easy, low-cost, anti-interference capability, high reliability are a number of advantages, is a close-up remote control, especially in indoor remote control optimized manner. 2.1.3 infrared diode characteristicsInfrared is not visible, people here are not aware of. Electronic technology is used infrared light emitting diode (also known as the IR emission diode) to generate infrared. Infrared remote control transceiver is using near-infrared transmission control instructions 0.76μm wavelength of ~ 1. 5μm. Near-infrared remote control as a light source, because there infrared light emitting diodes and infrared receiving device (photodiode. Transistor and PV) and the luminescence peak wavelength of lightby the general 0.8μm ~ 0. 94μm. in the near-infrared band, both of the spectrum is the coincidence to a good match, access to higher transmission efficiency and higher reliability. Commonly used infrared diode, and its shape is similar LED light emitting diodes, Its basic circuit shown in figure 2 -2. The triode plans for the switch, when the base added a driving signal, Transistor saturated conduction infrared LED D is also Wizard Link, issued infrared (near infrared about 0.93 μm). D. The pressure drop of about 1.4 V and the current general for 10-20mA. To adapt to the working voltage of the D loop resistance often as a series of infrared diode current limit resistance.When the circuit diagram of the infrared emission control corresponding to the controlled device, the control of the distance and D is proportional to the transmitting power. In order to increase the distance of infrared control, infrared diode D should work on the pulse state that work is the lifeblood of current. Because pulse light (optical modulation) the effective transmission distance and pulse is proportional to the peak current, only maximize peak current Ip, will increase the infrared distance. Ip increase is a way to reduce the pulse duty cycle, that is compressed pulse width τ some TV infrared remote control, its infrared luminescence of the pulse duty cycle of about 1/4-1/3; Some electrical products infrared remote control, its duty cycle of 1 / 10. Decreasing pulse duty cycle also enable low-power infrared LED distance of the greatly increased. Common infrared light emitting diodes, power is divided into small power (1 mW - 10mW). Chinese power (20mW - 50mW) and power (50mW - 100mW more) three categories. Use different power infrared LED, the allocation shouldbe driven by the corresponding power control. Figure 2 -2 by the reflected infrared light-emitting diodes to make produce optical modulation, Drivers only need to add the control of a certain frequency pulse voltage.Infrared transmitter and receiver in the way the two kinds of straight, and the second is reflective. Luminescence pointed straight pipe and tube receiver placed in a relatively controlled and fired on the two ends, a certain distance away from the middle; Reflective means luminescent tube and pipe parallel with the receiving peacetime, without always receiving tube light, luminescence only in possession of the infrared light reflected from encountered, the receiving tube received from the reflected infrared before work.2.2 infrared communication basic tenets2.2.1 infrared communication PrincipleCommunication is the use of infrared wavelength of 900 nm-infrared waves from 1000 to serve as an information carrier, through infrared technology between the two close communication and confidentiality of information transmitted. Infrared communication system structure include : part launcher, channel, the receiver part.Launcher source letter issued after the binary signal from the high-frequency modulated infrared LED sent, receiving device regard the reception of high-frequency signals from the infrared receiver tube after receiving further demodulation photoelectric conversion of the original information of a mass communication lose way. Afterwards the former Information received after receivingpart of the drive circuit connected to the expected completion of the various functions. To which the modulation coding style pulse width modulation (by changing the pulse width modulated signal PWM) and pulse modulation time (through change the pulse train interval time between the modulation signal PPM) two.2.2.2 infrared communication system elements(1) Launches : Currently there is a infrared wireless digital communications system sources of information including voice, data, images. Its methods of work for the launch of the receiver can be divided into different layout LOS way (Light-of-Sight , intracardiac way), diffuse (diffuse) mode. LOS way directional, it has good channel characteristics such advantages, but the existence of a "shadow" effect. difficult to achieve roaming function. Roaming means the main features of non-directional, and easy to implement roaming function, but its channel quality is better sometimes LOS way. Transmission of signals required for a few of (the sampling was quantified), the general need for baseband modulation, transmission, modulation, sometimes signal source coding, the above-driven signals from photoelectric converter complete optical signal transmission. Infrared wireless digital communications system and its scope of work-for-fired power distribution, the quality of the communication. While using various methods to improve optical transmitter power, the other using spatial diversity, holographic films and so on so diffuse light for the launch of space optical power evenly distributed.(2) Channel : infrared wireless digital communication channel refers to the transmitters and receivers in the space between. Due to natural light and artificial light sources such as light signalsin the context of intervention, and the source - Electrical Equipment, The optical noise and disturbances, infrared wireless digital communications in some occasions, poor quality, At this point needed to channel coding. Infrared wireless communication system, the optical signal reflection, light scattering and background noise and interference effects, Infrared wireless digital channel presence multi-path interference and noise, This is to improve the quality and access for high-speed applications should be addressed. Infrared wireless digital communication channel often used by the major optical components, optical filter, condenser, their role is : plastic, filter, depending on the field transformation, the band division, the lens can be used as launch-ray focusing, the use of optical filters filter out stray light, the use of optical lenses to expand the field of view receiver, able to make use of optical components for the link frequency division multiplexing, etc.. Infrared wireless communication channel optical noise : the natural noise (sunlight) and anthropogenic interference (fluorescent lighting). can be modulated by the transmission technology such as filters and adding to be addressed.(3) receivers : Channel optical signal from the optical receiver partially photoelectric conversion, In order to remove noise and intersymbol interference and other functions. Infrared wireless digital communications system receiver include optical receiver parts and follow-up sampling, filtering, judgment, quantity, balanced and decoding part. Infrared wireless optical receiver often used amplifier, and called for large-bandwidth, high gain, low noise and low noise, frequency response and channelimpulse response matched. To be suppressed by low-frequency noise and human disturbance needs a band-pass filter. To obtain large optical receiver scope and instantaneous field of view, often using spherical optical lens.2.2.3 infrared communications featureWireless communications are a lot of ways, some using infrared communication with the following characteristics :• The high frequency, wave length, and fired the energy concentrated space propagation attenuation coefficient can ensure the effective signal transmission;• infrared is the invisible light, strong confidentiality and use it as an information carrier. device when there is no visual pollution, it does no harm to the human body;• dissemination without limitation, and there is no question of frequency interference with radio-wave pattern, not on the spectrum resources to the relevant authorities for the application and registration, easy to implement;• has a good point, when the transmission equipment and infrared receiver ports line up straight, deviation of not more than about 15 degrees when infrared devices running the best effect;• through infrared or not bypassed and objects, data transmission, optical path can not be blocked;• currently produce and receive infrared signals in the technology is relatively mature, components small size, low cost production of simple, easy to produce and modulation advantages.2.3 infrared communication code based on the knowledgeUsually, infrared remote control transmitters will signal (pulse binary code) modulation at 38 KHz carrier, After buffer amplified sent to the infrared light-emitting diodes, infrared signals into firing away. Pulse binary code in a variety of formats. One of the most commonly used code is PWM (pulse width modulation code) and the PPM code (Pulse Code Modulation). The former said in a pulse width, pulse indicated 0. The latter pulse width, but the width of code-not the same, the codes represent a bit - and the digits represent narrow 0.Remote coding pulse signal (PPM code as an example) are usually guided by the code, the system code, the anti-code system, a feature code, functional anti-code signal components. Guide the code name for the initial code, by the width of 9 ms and the margin width of 4.5 ms to the low-level components (different remote control systems in the low-level high width of a certain distinction), remote coding used to mark the beginning of pulsed signals. System identification code is also called code, which used to indicate the type of remote control system, in order to distinguish other remote-control system, prevent the remote control system malfunction. Functional code is also called scripts, which represents the corresponding control functions, Receiver of the micro-controller functions under the numerical code to complete the various functions operating. Anti-code system and function codes are anti-system code and the functional code against code Anti-code can be joined to the receiver synchronization transmission process leads to errors. In order to improve performance and reduce interference power consumption, The remote control will be coded pulse frequency of 38 KHz (for the cycle of 26.3 ms) of the carrier signal pulse reshuffle system (PAM), and then sent to the bufferamplified infrared LED, the remote control signal transmitter away.Address code and data codes are composed of different pulse width expressed that the two narrow pulse "0"; 2 pulse width "1";a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Is the first part of a group a group of code, each code synchronization between separated. The plan is to enlarge the second half of a group code : a code from 12 AD (the address code plus data code For example, eight address code plus four data code), each with two AD-Pulse's : Pulse said the two "0"; 2 pulse width "1"; a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Realize fired at each fired at least four groups code, PT2272 only twice in a row to detect the same address code plus data code data will be the code "1" is driven The data should be output to drive margin and VT terminal for synchronous serial.红外遥控系统摘要红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。

电子信息工程专业外文翻译--客户信息管理系统

外文原文：Database Management Systems A database (sometimes spelled data base) is also called an electronic database , referring to any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval , modification, and deletion of data in conjunction with various data-processing operations .Databases can be stored on magnetic disk or tape, optical disk, or some other secondary storage device. A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage , and each field typically contains information pertaining to one aspect or attribute of the entity described by the database . Using keywords and various sorting commands, users can rapidly search , rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregate of data. Complex data relationships and linkages may be found in all but the simplest databases .The system software package that handles the difficult tasks associated with creating ,accessing, and maintaining database records is called a database management system(DBMS).The programs in a DBMS package establish an interface between the database itself and the users of the database.. (These users may be applications programmers, managers and others with information needs, and various OS programs.) A DBMS can organize, process, and present selected data elements form the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or poorly defined ,but people can “browse” through the database until they have the needed information. In short, the DBMS will “manage” the stored data items and assemble the needed items from the common database in response to the queries of those who aren’t programmers.A database management system (DBMS) is composed of three major parts:(1)a storage subsystem that stores and retrieves data in files;(2) a modeling 7and manipulation subsystem that provides the means with which to organize the dataand to add , delete, maintain, and update the data;(3)and an interface between the DBMS and its users. Several major trends are emerging that enhance the value and usefulness of database management systems; Managers: who require more up-to-data information to make effective decision Customers: who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts. Users: who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages. Organizations : that discover information has a strategic value; they utilize their database systems to gain an edge over their competitors. The Database Model A data model describes a way to structure and manipulate the data in a database. The structural part of the model specifies how data should be represented(such as tree, tables, and so on ).The manipulative part of the model specifies the operation with which to add, delete, display, maintain, print, search, select, sort and update the data. Hierarchical Model The first database management systems used a hierarchical model-that is-they arranged records into a tree structure. Some records are root records and all others have unique parent records. The structure of the tree is designed to reflect the order in which the data will be used that is ,the record at the root of a tree will be accessed first, then records one level below the root ,and so on. The hierarchical model was developed because hierarchical relationships are commonly found in business applications. As you have known, an organization char often describes a hierarchical relationship: top management is at the highest level, middle management at lower levels, and operational employees at the lowest levels. Note that within a strict hierarchy, each level of management may have many employees or levels of employees beneath it, but each employee has only one manager. Hierarchical data are characterized by this one-to-many relationship among data. In the hierarchical approach, each relationship must be explicitly defined when the database is created. Each record in a hierarchical database can contain 8only one key field and only one relationship is allowed between any two fields. This can create a problem because data do not always conform to such a strict hierarchy. Relational Model A major breakthrough in database research occurred in 1970 whenE. F. Codd proposed a fundamentally different approach to database management called relational model ,which uses a table as its data structure. The relational database is the most widely used database structure. Data is organized into related tables. Each table is made up of rows called and columns called fields. Each record contains fields of data about some specific item. For example, in a table containing information on employees, a recordwould contain fields of data such as a person’s last name ,first name ,and street address. Structured query language(SQL)is a query language for manipulating data in a relational database .It is nonprocedural or declarative, in which the user need only specify an English-like description that specifies the operation and the described record or combination of records. A query optimizer translates the description into a procedure to perform the database manipulation. Network Model The network model creates relationships among data through a linked-list structure in which subordinate records can be linked to more than one parent record. This approach combines records with links, which are called pointers. The pointers are addresses that indicate the location of a record. With the network approach, a subordinate record can be linked to a key record and at the same time itself be a key record linked to other sets of subordinate records. The network mode historically has had a performance advantage over other database models. Today , such performance characteristics are only important in high-volume ,high-speed transaction processing such as automatic teller machine networks or airline reservation system. Both hierarchical and network databases are application specific. If a new application is developed ,maintaining the consistency of databases in different applications can be very difficult. For example, suppose a new pension application is developed .The data are the same, but a new database must be created. Object Model The newest approach to database management uses an object model , in which records are represented 9by entities called objects that can both store data and provide methods or procedures to perform specific tasks. The query language used for the object model is the same object-oriented programming language used to develop the database application .This can create problems because there is no simple , uniform query language such asSQL . The object model is relatively new, and only a few examples of object-oriented database exist. It has attracted attention because developers who choose an object-oriented programming language want a database based on an object-oriented model. Distributed Database Similarly , a distributed database is one in which different parts of the database reside on physically separated computers . One goal of distributed databases is the access of information without regard to where the data might be stored. Keeping in mind that once the users and their data are separated , the communication and networking concepts come into play . Distributed databases require software that resides partially in the larger computer. This software bridges the gap between personal and large computers and resolves the problems of incompatible data formats. Ideally, it would make the mainframe databases appear to be large libraries of information, with most of the processing accomplished on the personal computer. A drawback to some distributed systems is that they are often based on what is called a mainframe-entire model , in which the larger host computer is seen as the master and the terminal or personal computer is seen as a slave. There are some advantages to this approach . With databases under centralized control , many of the problems of data integrity that we mentioned earlier are solved . But today’s personal computers, departmental computers, and distributed processing require computers and their applications to communicate with each other on a more equal or peer-to-peer basis. In a database, the client/server model provides the framework for distributing databases. One way to take advantage of many connected computers running database applications is to distribute the application into cooperating parts that are independent of one anther. A client is an end user or computer program that requests resources across a network. A server is a computer running 10software that fulfills those requests across a network . When the resources are data in a database ,the client/server model provides the framework for distributing database.A file serve is software that provides access to files across a network. A dedicated file server is a single computer dedicated to being a file server. This is useful ,for example ,if the files are large and require fast access .In such cases, a minicomputer or mainframe would be used as a file server. A distributed file server spreads the filesaround on individual computers instead of placing them on one dedicated computer. Advantages of the latter server include the ability to store and retrieve files on other computers and the elimination of duplicate files on each computer. A major disadvantage , however, is that individual read/write requests are being moved across the network and problems can arise when updating files. Suppose a user requests a record from a file and changes it while another user requests the same record and changes it too. The solution to this problems called record locking, which means that the first request makes others requests wait until the first request is satisfied . Other users may be able to read the record, but they will not be able to change it . A database server is software that services requests to a database across a network. For example, suppose a user types in a query for data on his or her personal computer . If the application is designed with the client/server model in mind ,the query language part on the personal computer simple sends the query across the network to the database server and requests to be notified when the data are found. Examples of distributed database systems can be found in the engineering world. Sun’s Network Filing System(NFS),for example, is used in computer-aided engineering applications to distribute data among the hard disks in a network of Sun workstation. Distributing databases is an evolutionary step because it is logical that data should exist at the location where they are being used . Departmental computers within a large corporation ,for example, should have data reside locally , yet those data should be accessible by authorized corporate management when they want to consolidate departmental data . DBMS software will protect the security and integrity 11of the database , and the distributed database will appear to its users as no different from the non-distributed database . In this information age, the data server has become the heart of a company. This one piece of software controls the rhythm of most organizations and is used to pump information lifeblood through the arteries of the network. Because of the critical nature of this application, the data server is also the one of the most popular targets for hackers. If a hacker owns this application, he can cause the company’s "heart" to suffer a fatal arrest. Ironically,although most users are now aware of hackers, they still do not realize how susceptible their database servers are to hack attacks. Thus, this article presents a description of the primary methods of attacking database servers (also known as SQL servers) and shows you how to protect yourself from these attacks. You should note this information is not new. Many technical white papers go into great detail about how to perform SQL attacks, and numerous vulnerabilities have been posted to security lists that describe exactly how certain database applications can be exploited. This article was written for the curious non-SQL experts who do not care to know the details, and as a review to those who do use SQL regularly. What Is a SQL Server?A database application is a program that provides clients with access to data. There are many variations of this type of application, ranging from the expensive enterprise-level Microsoft SQL Server to the free and open source mySQL. Regardless of the flavor, most database server applications have several things in common. First, database applications use the same general programming language known as SQL, or Structured Query Language. This language, also known as a fourth-level language due to its simplistic syntax, is at the core of how a client communicates its requests to the server. Using SQL in its simplest form, a programmer can select, add, update, and delete information in a database. However, SQL can also be used to create and design entire databases, perform various functions on the returned information, and even execute other programs. To illustrate how SQL can be used, the following is an example of a simple standard SQL query anda more powerful SQL query: 12 Simple: "Select * fromdbFurniture.tblChair" This returns all information in the table tblChair from the database dbFurniture.Complex: "EXEC master..xp_cmdshell ‘dir c:\’" This short SQL command returns to the client the list of files and folders under the c:\ directory of the SQL server. Note that this example uses an extended stored procedure that is exclusive to MS SQL Server. The second function that database server applications share is that they all require some form of authenticated connection between client and host. Although the SQL language is fairly easy to use, at least in its basic form,any client that wants to perform queries must first provide some form of credentials that will authorize the client; the client also must define the format of the request and response. This connection is defined by several attributes, depending on the relative location of the client and what operating systems are in use. We could spend a whole article discussing various technologies such as DSN connections, DSN-less connections, RDO, ADO, and more, but these subjects are outside the scope of this article. If you want t o learn more about them, a little Google’ing will provide you with more than enough information. However, the following is a list of the more common items included in a connection request. Database source Request type Database User ID Password Before any connection can be made, the client must define what type of database server it is connecting to. This is handled by a software component that provides the client with the instructions needed to create the request in the correct format. In addition to the type of database, the request type can be used to further define how the client’s request will be handled by the server. Next comes the database name and finally the authentication information. All the connection information is important, but by far the weakest link is the authentication information—or lack thereof. In a properly managed server, each database has its own users with specifically designated permissions that control what type of activity they can perform. For example, a user account would be set up as read only for applications that need to only access information. Another account should be used for inserts or updates, and maybe even a third 13account would be used for deletes. This type of account control ensures that any compromised account is limited in functionality. Unfortunately, many database programs are set up with null or easy passwords, which leads to successful hack attacks。

信息管理系统外文资料翻译

毕业设计(论文)外文资料翻译学院：计算机工程学院专业：通信工程姓名：学号：1081302228外文出处：/space.php?uid=7433&do=blog&id=5689(用外文写)附件： 1.外文资料翻译译文；2.外文原文。

注：请将该封面与附件装订成册。

附件1：外文资料翻译译文信息管理系统对于“管理信息系统”并没有一致的定义。

一些作者喜欢用其他术语代替，例如：“信息处理系统”“信息与决策系统”“组织信息系统”，或者干脆将“信息系统”用组织内具有支持操作、管理、决策职能的计算机信息处理系统代替。

这篇文章使用“管理信息系统”一词，是因为它是通俗易懂的，当涉及组织信息系统时也常用“信息系统”代替“管理信息系统”。

一个管理信息系统的定义，通常被理解为：一种集成用户机器系统，为组织提供信息支持运作、管理、决策职能。

该信息系统利用计算机硬件和软件；手工处理程序；模拟分析法计划、控制和决策；和数据库。

事实上，它是一个集成系统并不意味着它是单一的，单块集成结构；相反，它意味着零件适合加入整体设计。

内容定义如下：计算机为主的用户机器系统理论上，管理信息系统可以脱离计算机上而存在，但是计算机的存在可以让管理信息系统可行。

问题不是计算机是否被使用在管理信息系统中，而是信息的使用被计算机化的程度。

用户机器系统的概念暗示了, 一些任务最好由人执行, 其他的最好由机器做。

MIS的使用者是那些负责输入输入数据、指示系统或运用系统信息产品的人。

因为许多问题，用户和计算机建立了一个联合系统，其结果通过一套在计算机和用户之间的相互作用得到。

用户机器的相互作用是由用户连接在计算机上的输入-输出设备（通常是一个视觉显示终端）推动的。

计算机可以使一台个人机器服务于一名用户或者一台大规模的机器为一定数量通过终端由通信线路连接的用户服务。

用户输入-输出设备允许直接输入数据和紧接着输出结果。

例如：一个人使用计算机交互的在金融理财上通过在终端键盘输入提交“如果什么，怎么办？”之类的问题，结果几秒钟后便被显示在屏幕上。

论文电子信息类外文翻译

[2]韩奉天.TMS320F281x理论和施工技术的应用[M].清华大学出版社，2011年，第48-50页（中国）
[3]李炬光.ARM应用系统的开发[M].清华大学出版社，2003，第33-36页（中国）
[4]徐丽娜.神经网络控制[M].电子工业出版社，2003，第33-36页（中国）
[5]郑佩青.数字信号处理[M].清华大学出版社，2008年，第98-198页（中国）
3.3网络应用和测试
在实际应用中,收集的样本数据为272个随机组合的常用的负载类型。首先将200个样品作为测试部分,其余的72个样本则用于评价。在测试过程中系统采用梯度最速下降法，其中：学习因子η= 0.0075，动量因子α= 0.085。经测试结果表明,均方误差为0.118348,相关系数为0.994。以上数据则表明网络识别满足实际应用需求。
2.2多功能电源控制柜
多功能电源控制柜是整个系统的核心部分。它不仅对多用户的电气参数进行实时测量，而且还对负荷具有自动识别，切断危险载荷故障，记录数据和定时等功能。为了便于系统维护，模块化设计部分的应用程序有三个部分构成：包括输入接口板部分，主控板部分和输出接口板部分。
2.2.1输入和输出接口板
输入接口部分有16个模拟信号输入通道。第一个通道为相电压信号输入通道,其余15个通道为负载用户当前的信号通道。每个阶段的15个通道的各相电压和电流信号分别转换为0 ~ 3.3 v的模拟信号，再通过变压器、运算放大器和滤波器电路送入主控板TMS320F2812 ADC模块，以满足TMS320F2812 ADC模块的单极性特性。交流零电平的输入信号提高至1.6 v作为高精度电源参考值。输出接口部分同பைடு நூலகம்5个用户通道的继电器连接在一起。基于负载识别结果信息反馈和管理人员的命令指示，TMS320F2812的输出端口可以直接驱动ULN2804来控制相应的继电器。

电子信息工程外文翻译外文文献英文文献文献翻译

Technology and Application of Fieldbus Control System -------- IntelligentEquipment & Measurement And Control System Based on DeviceNetPromoted by the new technological revolution that automation control technology is tending digitization and internet in the field of automation industry, Shanghai Aton Electric Co., Ltd. developed Intelligent Equipment & Measurement And Control System Based on DeviceNet as a high and new technology industrialization model project. It was a state hi-tech development project of 2000 and was approved by the State Committee of Technology. Shanghai Aton Electric Co., Ltd. constructed production line of intelligent controller of pump and valve, relying on Shanghai Electric (Group) Corporation; constructed measurement and control system FCS R&D center of intelligent controller of pump and valve and built up mass production R&D basis, cooperating with Shanghai Jiaotong University and Shanghai University; constructed FCS remote diagnosis and service center of intelligent controller of pump and valve; constructed FCS training center of intelligent controller of pump and valve; founded mass production R&D basis along with the Rockwell Laboratory of Shanghai Jiaotong University and CIMS Center.1 Summary(1)Fieldbus control system is a system applied to field of production and microcomputerized measurement control equipment to realize both-way multinode serial communications. It is also called low-level control network for open, digital and multiplespot communications.Application: Flow Control System of Manufacturing; Process Control System; Traffic Control & Management; Building Automation. Features: Fieldbus control system is low-level low-bandwidth digital communication and control network in industrial system as well as open system connecting microcomputerized appearance. Intelligent instrument and controller are equal to microcomputer. They make up network with Fieldbus control system as the links to complete digital communication and other tasks.(2)Difference between FCS and DCS,FCS is updated control system after DCS integrated with digital control system and distributing control system. It solves the problem that in traditional DCS, devices made by different manufacturers cannot be connected. They can't realize exchange and operation to organize an network system with wider range of information sharing. It conquers the defect that special closed system for network should be used for communication in DCS to realize various functions of integrated automation. It turns the distributing structure combining concentration with deconcentration in DCS into new-type full distributing structure. Itreleases the control function to the field thoroughly and makes it possible to realize basic control function by means of fieldbus equipment itself. FCS breaks the traditional structure form of control system. The traditional analog control system adopts one-to-one equipment tie-wire and puts up connections respectively according to control loop. FCS adopts intelligent field equipment to place the control module, all input/output modules that used to be in the control chamber of DCS into field equipment. Since field equipment has ability to communicate, the field measuring and transferring instruments can transfer signals to actuating mechanism such as valve directly. Its control function can be fulfilled directly on the spot independent of the computer or control meter in the control chamber, which realizes thorough decentralized control.FCS adopts digital signals to replace analog signals so that multiple signals (including multiple operating parameter values, device status and failure information) can be transferred on a pair of cables. Meanwhile, it can give power supply to several devices. No switched block for analog/digital or digital/analog is needed besides fieldbus.(3) C haracteristics of FCS• Open System;• Interoperability;• replace ability of devices made by different manufacturers.• Intelligentize and Autonomy;• Field equipment completing basic functions of automatic control.• Decentralized System Structure;• Field Adaptability;• Relatively Strong Interference Killing Feature and Safety• Intelligentized local equipment can save investment and quantity of hardware• Saving installation expenses and cables• Saving daily maintenance expenses• Enhancing accuracy and reliability of system• Enhancing initiativeness of system integration for users(4) Development Background and Trend of Fieldbus Control System, With the rapid development of computer and computer network, FCS has been rapidly developed as the interlinked communication network between the field intelligentdevices in the field of process automation, building and traffic etc. Because FCS meets the needs that industrial control system is developing in the way of decentralization, network and intellectualized, it has become the focus of global industrial automation and been universally concerned by the whole world. FCS has causedgreat revolutions on the aspects of system structure and function system for the current production of automation instrument, distributing control system and programmable controller. It is predicted that FCS will be the general trends in a very long time in the future fore sure.2 APPLICATION OF RELAYThe product reliability generally refers to the operating reliability. It is defined as: the ability of accomplishing the specified function under prescribed conditions and in prescribed time. It consists of intrinsic reliability and application reliability. The intrinsic reliability is determined by product designing and manufacturing technique, and the application reliability is concerned with the correct application of users and the services provided by the manufacturer before and after selling. When using relay, the user should pay attention to the following items.2.1 Coil applied voltageIt is best to choose the coil applicative voltage according to the rated voltage in design, or choose the voltage according to the temperature rising curve. Using any coil voltage that is less than the rated voltage will affect the operation of the relay. The coil operating voltage refers to the voltage that is applied between the coil terminals. The voltage value between the two terminals must be guaranteed, especially when using enlargement circuit to energize the coil. Whereas, it will also affect the relay characteristics if the applied voltage exceeds the highest rated voltage. Exorbitant voltage will bring exorbitant coil temperaturerising, especially in high temperature ambient. Exorbitant temperature rising will damage the insulating material and affect the working safety of relay. For magnetic latching relay, energizing (or return) pulse width should not less than 3 times of the operating (or return) time, otherwise, the relay would be left on the middle-position state. When using solid-state components to energize the coil, the components dielectric strength must be above 80V, and the leakage of current must be as little as possible to ensure the relay to release.Energizing power source: Under 110% of the rated current, the adjusting ratio of the power source is less than 10% (or the output impedance is less than 5% of the coil impedance), the wave voltage of the DC power source is less than 5%. The AC wave is sine wave; the waviness coefficient is between 0.95~1.25; wave distortion is within ±10%; the frequency change is within ±1Hz or ±1% of the specified frequency (choosing the bigger value). The output power should not less than coil power consumption.2.2 Transient suppressionAt the moment when the coil power is stopped, peak-inverse voltage that is more than 30 times ofthe coil rated voltage is produced on the coil, which is harmful to the electronic circuit. Generally, the peak-inverse voltage is suppressedby transient suppression (cutting-peak) diode or resistance to limit the peak-inverse voltage within 50V. But the diode in parallel connection will delay3~5 times of the release time. If the request of the release time is high, a suitable resistance in series can be putted with and at one end of the diode.The power supply to relays in parallel connection and series connection, When several relays in parallel connection are supplied, the relay that the peak-inverse voltage is higher will release power to the relays that the peak-inverse voltage is lower. The release time of the relay will delay. So the relays in parallel connection should be controlled separately to eliminate mutual influence.The relays with different coil resistance and power can'bt e used in series, otherwise, the relay that the coil current is higher in the series circuit can'otperate reliably. Only the relays of the same specification can be used in series, but the peak-inverse voltage will be increased and the peak-inverse voltage should be suppressed. Resistance in series can be used to bear the part voltage that exceeds the rated voltage of the coil according to the ratio of the divided voltage.2.2.1 Contact loadThe load applied to the contacts should be accordant to the rated load and characteristics of the contacts. A load that is not applied according to the rated value range will cause problem. The relay that is only suitable for DC load can used in ' t be AC occasions. The relay that can switch 10A load can ' t always reliably operate in low level load (less tha n 10m AX6A) or in dry circuit occasi ons. The relay that can switch single-phase AC power source isn 'atlways suitable to switch two single-phase AC loads that aren 't synchronous; the relay that is onlyiesdpteocisfwitch the load of AC 50Hz(or 60Hz)can't be used to switch AC load of 400Hz.2.2.2 Parallel and series connection of contactsThe contacts used in parallel connection can ' t increase the load current, becausethe operating times of several sets of contacts are absolutely different; that is to say, there is still only a set of contacts switching the increased load. This would damage or weld the contacts and make the contacts can ' t close or open. The parallel connectionof the contacts can decreasehte misplay of “ break ” . But the parallel connection of the contacts would increase the misplay of “ freezing ”. Because the misplay of “bre the main pattern of invalidation of contacts, the parallel connection can increase the reliability and can be used on the pivotal part of equipments. But the applied voltage should not exceed the highest operating voltage of the coil and should not less than 90% of the rated voltage, otherwise, the coil life and the applicative reliability would be damaged. The series connection of the contacts can increasethe load voltage. The amount of the contact sets is equal to the times that the load voltage can be increased.The series connection of contacts can decrease the misplay of “ freezing ”, but it w increase the misplay of “ break ”An. yway, when using redundant technology to increase the operating reliability of contacts, the characteristics and size and the failure mode of load must be considered.2.2.3 Switching speedThe switching speed should not exceed the reciprocal of 10 times of the sum of operating and release time (times/s), otherwise, the contacts can ' t switch on stead Magnetic latching should be used under the pulse width specified in the technique criterion, or the coil may be damaged.3 RVT DISTRIBUTING ELECTRICITY INTEGRATE TEST APPARATUSBasic functionMeasure asupervision:Three mutually electric voltage/electric current/ power factor with a great achievement/ power without a great achievement/electricity with a greatachiverment/electricity/homophonic-wave electric voltage/ homophonic-wave electric/ current Day electric voltage/ electric current biggest and minimum value/fire for the failure Electric voltage over top, the limit/ lack mutually of time homophonic-wave analyzes is up to 13 times.The data is stored for 2 months. The data communicateRS232/485 communicating connect，The way in communicating can adopt the spot communicating or the long range communicating. ，Possible to settle invoke orthe solid hour invokes, responding to the modification and long ranges control of the parameter. Without power compensationTaking physics measuresas the power factor without a great achievement,the power factor with a great achievement and the dull place without power compensation;Y+ the combination method of the △，Y+ the △ connects the line method，Y+ △ , Y, the △ connects the line method. Data managementAccording to WINDOW98 operation terrace, data in communication automatically reports born statement, curve and pillar form diagrams. Circulation of the protectionWhen the charged barbed wire net of mutually electric voltage over press, owe to press, and a super limit hour fast cut off in expiation of capacitor，When the charged barbed wire net lacks mutually or super limit in the preface of zero hour fast cut off in expiation of capacitor. screen manifestationChinese operation interface ，Adopt 128*64 the back light liquid crystal display.The solid hour shows the charged barbed wire net relevant parameter.view manifestation to place the parameter.现场总线控制系统的技术和应用随着新的科学技术革命的出现，在自动化工业领域中，自动控制技术的发展趋向于数字化和网络互联化。

电子信息工程专业毕设文献翻译附英文原文

5.3. 时钟独立的显性误差
对于每一个特定的GPS时钟，在每个适用的时间从KF1相位偏差估计值减去 UECC估计值，去估计其OEIC的相位。在测量加工， OEIC包含在几部分纳秒内(见图4)。图4展示了的两种情况下地面工作站时钟S1的OEIC。在蓝线的可见区间和 KF1测距处理显然有别于没有测量的传播间隔。在测量处理期间，KF1估计误差的观察目标部分包含在几部分纳秒内。OEIC的协方差顺序计算需要每个时间点的 KF1相位偏差估计误差和UECC估计误差的互协方差矩阵值。我尚未能计算这
X K 1|K 1 X K 1|K K K 1[ y K 1 y( X K 1|K )]

Hale Waihona Puke （5）5. 难以观察的 GPS 时钟系统
GPS时间是由作战空军（USAF）卡尔曼滤波器处理 GPS伪距测量产生的。 GPS时间是多个GPS时钟的平均相位，可是，通过 GPS伪距测量，每个运行的GPS 时钟的时钟相位是难以观察的，演示如下。GPS导航星的轨道参数是从GPS伪距观测可观察到的。从GPS伪距测量可以得到USAF（美国空军）卡尔曼滤波器估计轨道参数和时钟同步参数，因此以这种方式将状态估计值分为隐式的时钟参数子集和显式的轨道参数子集。通过应用谢尔曼有关MU函数的定理，演示了这种分区方式。
4.3.2. 非线性函数 MU
计算 n ×1 矩阵滤波器增益 K K 1 ：
T T 1 K K 1 PK 1|K H K 1 [ H K 1 PK 1| K H K 1 R K 1 ]
（4）
滤波器测量更新 n×1 状态估计矩阵 X K 1|K 1 ，观测 yK+1 得

态估计误差协方差方阵（正特征值）

[电子信息工程] 本科论文英文文献翻译

外文资料翻译学院：电子工程学院系（专业）：电子信息工程班级：电子061姓名：学号:一：外文原文3G TECHNOLOGYAlthough the technology behind 3G may seem complicated, the ways in which 3G will affect all of our lives are easy to imagine. Just imagine having a combined camera，videocamera，computer, stereo，and radio included in your mobile phone. Rich-media information and entertainment will be at your fingertips whenever you want anywhere there is a wireless network。

Mobile communication is moving from simple voice to rich media, where we use more of our senses to intensify our experiences.But not all of this will happen at once. 3G is an evolution to a communications ideal that no one completely understands yet. What we do know is that mobile multimedia will hit the Japanese markets in 2001，and Europe and North America will follow soon after。

3G brings together high-speed radio access and IP-based services into one, powerful environment. The step towards IP is vital. IP is packet-based，which in simple terms，means users can be ”on line” at all times，but without having to pay until we actually send or receive data. The connectionless nature of IP also makes access a lot faster：file downloads can take a few seconds and we can be connected to our corporate network with a single click.3G introduces wideband radio communications, with access speeds of up to 2Mbit/s. Compared with today's mobile networks，3G will significantly boost network capacity — so operators will be able to support more users, as well as offer more sophisticated services.3G - At home3G is going to affect our home and social lives in many ways. The services that 3G enables will help us to manage our personal information，simplify tasks such as grocery shopping，make better use of our time and offer services that are just fun to use。

电子信息外文文献译文

XXXX学院毕业设计（论文）外文参考文献译文本2012届原文出处A Novel Cross-layer Quality-of-service ModelFor Mobile AD hoc Network毕业设计(论文)题目基于COMNETIII的局域网的规划与设计院（系）电气与电子信息学院专业名称电子信息工程学生姓名学生学号指导教师A Novel Cross-layer Quality-of-service ModelFor Mobile AD hoc NetworkLeichun Wang, Shihong Chen, Kun Xiao, Ruimin Hu National Engineering Research Center of Multimedia Software, Wuhan UniversityWuhan 430072, Hubei, chinaEmail:******************Abstract:The divided-layer protocol architecture for Mobile ad hoc Networks (simply MANETs) can only provide partial stack. This leads to treat difficulties in QoS guarantee of multimedia information transmission in MANETs, this paper proposes Across-layers QoS Model for MANETs, CQMM. In CQMM, a core component was added network status repository (NSR), which was the center of information exchange and share among different protocol layers in the stack. At the same time, CQMM carried out all kinds of unified QoS controls. It is advantageous that CQMM avoids redundancy functions among the different protocol layers in the stack and performs effective QoS controls and overall improvements on the network performances.Keyword: Cross-layers QoS Model, Mobile Ad hoc Networks (MANETs), Network Status Repository (NSR), QoS Controls.1 introductionWith the rapid development of multimedia technologies and the great increase of his bandwidth for personal communication, video and video services begin to be deployed in MANETs. Different from static networks and Internet, multimedia communications in MANETs such as V oice and Video services require strict QoS guarantee, especially the delay guarantee. In addition, communication among different users can be integrated services with different QoS requirements. These lead to great challenges in QoS guarantee of multimedia communication in MANETs. There are two main reasons in these: 1) MANETs runs in atypical wireless environment with time-varying and unreliable physical link, broadcast channel, and dynamic and limited bandwidth and so forth. Therefore, it can only provide limited capability for differentiated services with strict QoS requirements [1].2) It is difficult that traditional flow project and access control mechanism are implemented because of mobility, multiple hops and self-organization of MANETs.At present, most researches on QoS based on traditional divided-layer protocol architecture for MANETs focus on MAC protocol supporting QoS [2], QoS routingprotocol [3] and adaptive application layer protocol with QoS support [4], and so on. It is avoid less that there will be some redundancies on functions among the different protocol layers in the stack. This will increase the complexity of QoS implementation and cause some difficulties in overall improvement on the network performances. Therefore, it is not suitable for MANETs with low processing abilityIn recent years, the cross-layers design based on the partial protocol layers in MANETs was put forward.[1] proposed the mechanism with QoS guarantee for heterogeneous flow MAC layer.[5,6,7,8] did some researches on implementing video communication with QoS guarantee by exchange and cooperation of information among a few layers in MANETs. These can improve QoS in MANETs’communication to some extent. However, MANETs is much more complex than wired system and static network, and improvements on QoS guarantee depend on full cooperation among all layers in the protocol stack. Therefore, it is difficult for the design to provide efficient QoS guarantee for communication and overall improvements on the network performances in MANETs.To make good use of limited resources and optimize overall performances in MANETs, this paper proposes a novel cross-layer QoS model, CQMM, where different layers can exchange information fully and unified QoS managements and controls can be performed.The rest of the paper is organized as follows. CQMM is described in section 2 in detail. In section 3, we analyze CQMM by the comparison with DQMM.The section 4 concludes the paper.2. A CROSS-LAYER QOS MODEL FOR MANETS-CQMM2.1 Architecture of CQMMIn MANETs, present researches on QoS are mostly based on traditional divided-layer protocol architecture, where signals and algorithms supporting QoS are designed and implemented in different layers respectively, such as MAC protocol supporting QoS in data link layer [9], routing protocol with QoS support in network layer[10.11],and so forth. It can be summarized as A Divided-layer QoS Model for MANETs, DQMM (see fig.1).In DQMM, different layers in the protocol stack are designed and work independently; there are only static interfaces between different layers that are neighboring in logic; and each protocol layer has some QoS controls such as error control in logic link layer, congestion control in network, etc. On the one hand, DQMM can simplify the design of MANETs greatly and gain the protocols with high reliability and extensibility. On the other one, DQMM also has some shortcomings: 1) due to the independent design among he different protocol layers, there are some redundancy functions among the different protocollayers in the stack, 2) it is difficult that information is exchanged among different layers that are not neighboring in logic, which leads to some problems in unified managements, QoS controls and overall improvements on the network performances.Fig.1Therefore, it is necessary that more attention are focused on the cooperation among physical layer data link layer, network layer and higher when attempting to optimize performances of each of layer in MANETs. For this reason, we combine parameters dispersed in different layers and design a novel cross-layer QoS model, CQMM, to improve the QoS guarantee and the overall network performances. The architecture of CQMM is provided in fig 2From fig.2, it can be seen that CQMM keeps the core functions and relative independence of each protocol layer in the stack and allows direct information exchange between two neighboring layers in logics to maintain advantages of the modular architecture .On the basic of these, a core component is added in CQMM, Network Status Repository (simply NSR).NSR is the center, by which different layers can exchange and share information fully. On the one hand, each protocol layer can read the status information of other protocol layers from NSR to determine its functions and implementation mechanisms. On the other one, each protocol layer can write its status information to NSR that can be provided with other layers in the protocol stack. In CQMM, the protocol layers that are neighboring in logics can exchange information directly orindirectly by NSR, and the protocol layers that are not neighboring in logics can exchange information using cross-layer ways via NSR. Therefore, information exchange is flexible in CQMM.All kinds of QoS controls in CQMM such as management and scheduling of network resources, network lifetime, error control, and congestion control and performance optimization and so on are not carried out independently. On the contrary, CQMM is in charge of the unified management and all QoS controls by the cooperation among different protocol layers in the stack. Each QoS control in MANETs is related to all layers in the protocol stack, and also constrained by all layers in the stack. The results of all QoS operations and managements are fed back to the different layers and written back to NSR, which will become the parameters of all kinds of QoS controls in MANETs.2.2 protocol design in CQMMIn CQMM, the protocol designs aims at the full and free information exchange and cooperation among different protocol layers to avoid possible redundancy functions when maintaining the relative independence among different layers and the advantages of the modular architecture.Physical layer: Physical layer is responsible for modulation, transmission and receiving of data, and also the key to the size, the cost and the energy consumption of each node in MANETs. In CQMM, the design of physical layer is to choose the transmission media, the frequency range and the modulation algorithm wit the low cost, power and complexity, big channel capability and so on, according to the cost of implementation, energy constraint, and capability and QoS requirements from high layer.Data link layer: The layer is low layer in the protocol stack and can be divided into two sub-layers: logic link sub-layer and MAC sub-layer. Compared with high layers, data link layer can sense network status in MANETs earlier such as the change of channel quality, the network congestion and so on. Therefore, on the one hand data link layer can perform the basic QoS controls such as error control and management of communication channel. On the other one, the layer can be combined with high layers to establish, choose and maintain the routing faster, prevent the congestion of the network earlier, and choose appropriate transport mechanisms and control strategies for transport layer.Network layer: The design and implementation of network layer protocol in CQMM is to establish, choose and maintain appropriate routings by taking into consideration the power, the cache, the reliability of each node in a routing. QoS requirements of services from high layer such as the bandwidth and the delay, and implementation strategies oferror control in logic link sub-layer and the way of the channel management in MAC sub-layer.Transport layer: In CQMM, the protocol design of transport layer needs to be aware of both functions and implementation mechanism of lower layers such as the way of error control in data link layer, the means to establish, choose and maintain routing in the network layer, and QoS requirements from the application layer, to determine corresponding transmission strategies. In addition, the transport layer also needs to analyze all kinds of events from low layers such as the interrupt and change of the routing and the network congestion, and then respond properly to avoid useless sending data.Application layer: There are two different strategies in the design of the application layer: 1) differentiated services. According to the functions provided by the low layers applications are classed as the different ones with different priority levels. 2) Application-aware design. Analyze specific requirements of different applications such as the bandwidth, the delay and the delay twitter and so on, and then assign and implement the functions for each layer in the protocol stack according to the requirements.2.3 QoS Cooperation and Management in CQMMIn CQM, the core of QoS cooperation and management is that NSR acts as the exchange and share center of status information in protocol stack, and by the full exchange and share of network status among different protocol layers the management and scheduling of the network resources and the overall optimization of the network performances can be implemented effectively. The management and scheduling of the network resources, the cross-layer QoS cooperation and the overall optimization of the network performances.Management and scheduling of network resources: Network resources include all kinds of resources such as the cache, the energy and the queue in each node, and the communication channel among nodes and so froth. In CQMM, the management and scheduling of the network resources are not to the unified management and scheduling of the network resources and full utilization of limited resources in order to increase the QoS of all kinds of communication.QoS cooperation and control: In CQMM, all kinds of QoS controls and cooperation such as the rate adaptation, the delay guarantee and the congestion control and so on, are not implemented by each layer alone, but completed through the operation of all layers in the protocol stack. For example, the congestion in MANETs can be earlier prevented and controlled by the cooperation among different layers such as ACK from MAC sub-layer,the routing information and the loss rate and delay of package from network layer, and the information of rate adaptation in transport layer and so on.Performances Optimization: In CQMM, the optimization of the network performances aims to establish a network optimization model constrained by all layers in the protocol architecture and finds the “best”ways according to the model in order to improve the overall performances in MANETs.3. ANALYSIS OF CQMMPresent QoS models for MANETs can mainly be classed as a QoS model based on traditional divided-layer architecture DQMM and a cross-layer QoS model proposed by this paper CQMM. QoS model used by [1, 5-8] is to some extent extended on the basis of DQMM in nature. Here, we only compare CQMM with DQMM3.1 Information ExchangeDifferent protocol architecture and principle between CQMM lead to great differences in the means, the frequency, the time and the requirement of the information exchange, (see table 1)From Table 1, it can be seen that compared wit DQMM CQMM has some advantages: 1) more flexible information exchange. Neighboring layers can information by the interfaces between layers or NSR, and crossing layers may exchange information through NSR; 2) simpler transform in information format. Different layers can exchange information by NSR, so these layers only need to deal with the format transform between the layers and NSR;3)lower requirements. The protocol layers can read them in proper time Information from different protocol layers temporarily stored in NSR, so the layers exchanging information are not required to be synchronous in time;4) more accurate control. NSR in CQMM can store information of some time from the different layers, which is advantageous to master the network status and manage the network more accurately. However, these require higher information exchange frequencies among the different layers,, more processing time of each node, and more communication among them.。

电子信息工程论文(英文)【精选文档】

Electronic and information engineering is the application of the computer and modem technology for electronic information control and information processing the discipline， the main research information acquisition and processing，electronic equipment and information system design, development, application and integration. Now, electronic and information engineering has covered many aspects of the society，like telephone exchange station how to deal with various phone signal, a mobile phone is how to transfer our voice even image， the network around us how to transfer data, and even of the army of the information age how to confidential information transmission， are involved in electronic and information engineering application technology。

We can through some basic knowledge learning know these things， and able to apply more advanced technology in new product research and electronic and information engineering is professionalThis program is to cultivate master the modern electronic technology theory, familiar with electronic system design principle and design method， have stronger computer, foreign language and corresponding engineering technology application ability, facing the electronic technology, automatic control and intelligent control, computer and network technology， electronic, information，communication field of broad caliber， the high quality, comprehensive development of integrated with innovation ability engineering technology talent development.Electronic information engineering major is learning the basic circuit of knowledge, and master the computer processing with the method of information. The first to have solid mathematical knowledge, for physics requirement is high， and mainly electrical； To learn many circuit knowledge, electronic technology, signal and system, computer control principle， communication principle，basic courses. Learning in electronic and information engineering design, to themselves have to connect with computer some circuit experiment, to operate and use tools requirements is also higher。

电子信息工程专业客户信息管理系统大学毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译文献、资料中文题目：客户信息管理系统文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：电子信息工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文文献翻译（本科学生用）题目：客户信息管理系统_外文资料Database Management Systems A database (sometimes spelled data base) is also called an electronic database , referring to any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval , modification, and deletion of data in conjunction with various data-processing operations .Databases can be stored on magnetic disk or tape, optical disk, or some other secondary storage device. A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage , and each field typically contains information pertaining to one aspect or attribute of the entity described by the database . Using keywords and various sorting commands, users can rapidly search , rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregate of data. Complex data relationships and linkages may be found in all but the simplest databases .The system software package that handles the difficult tasks associated with creating ,accessing, and maintaining database records is called a database management system(DBMS).The programs in a DBMS package establish an interface between the database itself and the users of the database.. (These users may be applications programmers, managers and others with information needs, and various OS programs.) A DBMS can organize, process, and present selected data elements form the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or poorly defined ,but people can “browse”through the database until they have the needed information. In short, the DBMS will “manage” the stored data items and assemble the needed items from the common database in response to the queries of those who aren’t programmers.A database management system (DBMS) is composed of three major parts:(1)a storage subsystem that stores and retrieves data in files;(2) a modeling and manipulation subsystem that provides the means with which to organize the data and to add , delete, maintain, and update the data;(3)and aninterface between the DBMS and its users. Several major trends are emerging that enhance the value and usefulness of database management systems; Managers: who require more up-to-data information to make effective decision Customers: who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts. Users: who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages. Organizations : that discover information has a strategic value; they utilize their database systems to gain an edge over their competitors. The Database Model A data model describes a way to structure and manipulate the data in a database. The structural part of the model specifies how data should be represented(such as tree, tables, and so on ).The manipulative part of the model specifies the operation with which to add, delete, display, maintain, print, search, select, sort and update the data. Hierarchical Model The first database management systems used a hierarchical model-that is-they arranged records into a tree structure. Some records are root records and all others have unique parent records. The structure of the tree is designed to reflect the order in which the data will be used that is ,the record at the root of a tree will be accessed first, then records one level below the root ,and so on. The hierarchical model was developed because hierarchical relationships are commonly found in business applications. As you have known, an organization char often describes a hierarchical relationship: top management is at the highest level, middle management at lower levels, and operational employees at the lowest levels. Note that within a strict hierarchy, each level of management may have many employees or levels of employees beneath it, but each employee has only one manager. Hierarchical data are characterized by this one-to-many relationship among data. In the hierarchical approach, each relationship must be explicitly defined when the database is created. Each record in a hierarchical database can contain only one key field and only one relationship is allowed between any two fields. This can create a problem because data do not always conform to such a strict hierarchy. Relational Model A major breakthrough in database。

电子信息专业翻译文件原文

A novel DC-AC Single Phase Resonant Inverter usingsoft switching boost converterDong-jo Won1, Chung-Yuen Won1, Su-Won Lee2, Yong-Chae Jung3, and Dong-sung Oh41 School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746, Korea2 Center for Advanced IT HRD with closed Industry Cooperation, Sungkyunkwan University, Suwon, 440-746, Korea3Department of Electronic Engineering, Namseoul University, Cheonan, 331-707, Korea4 SAMSUNG Electro-Mechanics CO., LTD. CDS Division Power Business Team, Suwon, 443-803, KoreaAbstract-In this paper, a novel DC-AC single phase inverter is proposed. When the switches are turned on and off, a conventional inverter generates switching loss because of the hard switching. Thus, the inverter loss is increased. Proposed system contains auxiliary circuit. The converter stage switches perform soft-switching because of the auxiliary circuit. Also inverter stage switches perform ZVS when the dc-link voltage is zero. Therefore all switches perform soft-switching when the switches are turned on and off. Thus the proposed system reduces switching loss and voltage stress.I.I NTRODUCTIONNowadays, the power electronics are required to develop smaller, lighter, less expensive and reliable system. In order to operate these systems, a switching frequency has to be increased. But, increasing the inverter switching frequencies is dependent on the advances in device technology and makes higher switching losses. [1], [2]To solve this problem, the soft switching techniques have been adopted in the inverter circuit. By the soft-switching techniques, the switching losses are ideally zero and the switching frequencies can be increased to above the audible range. In this paper, a novel DC-AC single phase resonant inverter using soft switching boost converter is proposed. This proposed inverter consists of soft-switching boost converter and H-bridge inverter. The soft-switching boost converter in proposed inverter additionally has resonant inductor L r, resonant capacitor C r, bridge diode and auxiliary switch Q2. When the resonance between resonant inductor and capacitor is generated, the converter switches are turned on and off with soft-switching. Also H-bridge inverter switches are turned on and off with ZVS when the auxiliary switch is turned off. So all of the switches are turned on and off with soft-switching. [3], [4], [5], [6] Therefore the novel DC-AC single phase resonant inverter using soft-switching boost converter can reduce the switching loss and voltage stress.In this paper, we have analyzed the operational principle of the proposed resonant inverter. Simulation results presented to confirm the theoretical analysis.II.P ROPOSED I NVERTERFig. 1 Proposed novel DC-AC single phase resonant inverter using soft switching boost converterFig. 1 shows the proposed a novel DC-AC single phase resonant inverter using soft-switching boost converter. The auxiliary circuit in proposed inverter consists of an auxiliary switch, resonant inductor, resonant capacitor, and bridge diode. So, the main switch is turned on with ZCS and turned off with ZVS. Also the auxiliary switch is turned on and off with ZVS. Therefore, the converter stage switches perform the soft-switching.The H-bridge inverter performs the soft-switching under the influence of the dc-link voltage. When the auxiliary switch is turned off with ZVS, the dc-link voltage is zero. The inverter switches are turned on and off with ZVS while the dc-link voltage becomes zero. So all of switches in proposed inverter are turned on and off with soft-switching.Therefore, the proposed soft-switching inverter has many advantages like as improved efficiency, low switching losses, low voltage stress, reduced acoustic noise and EMI. Another significant advantage of the proposed topology is an excellent PWM capability due to not only variable link pulse but also variable pulse position.The proposed inverter operation mode analysis can be divided into six modes, as shown in Fig 2. Fig 3 shows the proposed waveforms for the novel DC-AC single phase resonant inverter using soft-switching boost converter.Fig. 2 Operation mode diagrams for the novel DC-AC single phase resonant inverter using soft-switching boost converterFig.3 Operation waveforms for the novel DC-AC single phase resonant inverter using soft-switching boost converterIII. E QUVALENT C IRCUIT A NALYSISMode 1 (t 0≤t<t 1): The resonant capacitor is discharged throughresonant path C r and L r . The resonant inductor current begins to increase linearly from zero. Therefore, the main switch is turned on with ZCS influenced by resonant inductor. The energy of the main inductor is delivered to the load through the switches (S 1, S 4).The next mode is started as soon as the resonant capacitor has fully discharged. In this mode, the main inductor current is given by(1)(2)Initial resonant inductor current and capacitor voltage given by(3)(4)The resonant period isThe resonant impedance is(6)The inductor current and resonant capacitor voltage in resonant period are given by,(7)(8)Mode 2 (t 1≤t<t 2): When the resonant capacitor is fully discharged to Mode1, the anti-parallel diodes in inverter switches constitute current path. At this time, the inverter stage is zero. When the inverter stage is in the zero voltage condition, the inverter switches are given to PWM signal (S 1, S 4). So, inverter switches are turned on and off with ZVS. This mode is maintained when the main switch is turned-off. The main inductor current is given by(9)The resonant inductor current and resonant capacitor voltage are given by(10)(11)Mode 3 (t 2≤t<t 3): When the switch is turned off with ZVS, the resonant inductor releases energy . Thus, the bridge diode is turned on. The dc-link capacitor is transferred to main inductor and resonant inductor energy through the bridge diode. The resonant capacitor starts to charge main inductor energy. At that time, the resonant inductor current and resonant capacitor voltage are given by(12)(13)(14)In this mode, the main inductor current is given by(15)(16)Mode 4 (t 3≤t<t 4): When the resonant inductor energy is fully released, the bridge diode is turned-off. This mode is maintained until the resonant capacitor voltage becomes 400[V]. The main inductor current flows continuously through the inverter switches (S 1, S 4). In this mode, resonant capacitor voltage is given by(17)(18)Resonant inductor current is given by(19)Mode 5 (t 4≤t<t 5): This mode is started when the resonant capacitor is fully charged. After that, the auxiliary switch is turned on with ZVS because the switch voltage is zero. When the main inductor current decreases linearly, the dc-link capacitor is charged from the main inductor energy. Because the main inductor current flows through the anti-parallel diode, the auxiliary switch voltage is zero voltage. When the auxiliary switch current path is changed, the next mode starts. In this mode, the main inductor current can be expressed as(20)1m in 1010()()cos ()sin ()o Lr L o o r r r Vi t I I I t t t t Z ωω=−+−+⋅−r Z =11010()()()in L L Vi t i t t t L =+−r t =1010()cos ()sin ()o cr o r o r r rVv t v t t I Z t t Z ωω=−−⋅⋅−11121()()()inL L V I t I t t t L=+−10min 0()()L Lr i t I i t ≅≅0()0Lr i t ≅0()cr out v t V ≅12()()()Lr Lr Lr i t i t i t ≅≅12()()0cr cr v t v t V≅≅()3232()()cos ()sin ()L o in Lr o o r r r I Ii t v v t t t t C Z ωω=+−−−−32()32()cos ()()sin ()cr o o r r in o L o r v t v v t t Z I I I t t ωω=−−+−−−11232()()()o inL L v vI t I t t t L−=−−12max()L I t I ≅3()0Lr i t ≅1433()()()L ocr C I I v t t t V t C−=−+34()()0Lr Lr i t i t ≅≅4()cr outv t V ≅11454()()()o inL L v v I t I t t t L−=−−Mode 6 (t 5≤t<t 6): In this mode, the auxiliary switch current path is changed because the dc-link capacitor starts to discharge. Therefore, the load is supplied the energy by the dc-link capacitor and main inductor. This mode maintains that the main inductor current equal to the resonant current. The main inductor current in this mode is expressed as(21)(22)(23)(24)After this mode ends, returning the mode 1.IV. S IMULATION R ESULTThis proposed resonant inverter is simulated to demonstrate the features and theoretical analysis. A 3kW prototype resonant inverter is built and simulated using the PSIM tool. The parameters used for simulations are as follow TABLE1.TABLE1. Simulation parametersFig. 4 shows simulation waveforms of converter stage in resonant DC-AC single phase inverter. During the resonance period between the resonant inductor and the resonant capacitor, the main switch and auxiliary switch are turned on and off with ZVS and ZCS.Fig.4 Simulation waveforms of converter stage in resonant DC-AC singlephase inverterFig.5 Principle operation waveforms of the proposed resonant inverterFig. 6 The waveforms of the voltage and the current of the main switchat turned-on and off with ZVSV dc 200[V] V dc-link 400[V] Main inductor 1000[μH] Resonant inductor 10[μH] Resonant capacitor 10[nF] DC-Link-Cap 1000[μF] Con. Switching Freq. 30[kHz] Inv. Switching Freq.15[kHz]11565()()()o inL L v v I t I t t t L−=−−56()()0Lr Lr i t i t ≅≅4()cr outv t V ≅16min ()L i t I ≅Fig. 7 The waveforms of the voltage and the current of the auxiliary switch at turned-on and off with ZVSFig. 8 The waveforms of the voltage and the current of the inverter switch at turned-on and off with ZVSFig. 5 presents principle operation waveforms of the proposed resonant inverter. When the switch current in inverter stage flows through the anti-parallel diode of inverter switch, the inverter switches maintain the freewheeling mode. Therefore, all inverter switches perform the soft-switching under the zero voltage condition.Fig.6 shows the main switch waveforms of the voltage and the current when the switch is turned and off with ZVS. Fig.7 shows the waveforms of the voltage and the current of the auxiliary switch at turned-on and off with ZVSDuring the resonant period, the bridge diode is turned on. At this time, dc-link capacitor is charged from resonant inductor energy when the current flows through the anti-parallel diode of auxiliary switch. Therefore, the auxiliary switch has zero-voltage condition. At this time, the switch is turned on with ZVS.Fig. 8 presents the waveforms of the voltage and the current of the inverter switch at turned-on and off with ZVS. All inverter switches have freewheeling mode, under the zero voltage condition. After this mode ends, returning the mode 1.V. C ONCLUSIONIn this paper, we proposed a novel DC-AC single phase resonant inverter using soft-switching boost converter. In this topology, all switches perform a soft switching by resonance between the resonant inductor and capacitor. So, the proposed topology can reduce the switching loss and voltage stress. The proposed inverter is analyzed through the operation mode, and its validity is proven through simulation.VI. A CKNOWLEDGMENTThis work is outcome of the fostering project of the Specialized Graduate School supported financial Ministry of Knowledge Economy (MKE).VII.R EFERENCES[1] D. M. Divan, G. Skibinski, “Zero switching loss inverters for highpower applications,” IEEE IAS Rec., pp. 627-634, 1987.[2]S.R. Park, S.H. Park, C.Y. Won, Y.C. Jung, "Low loss soft switchingboost converter", 2008 13th International Power Eletronics and Motion Control Conference (EPE-PEMC 2008) pp. 181 - 186. 2008[3]K. Wang, G. Hua, and F. C. Lee, “"Analysis, design and ZCS-PWMboost converters” in Proc. IEEJ Int. Power Electronics Conf., pp.1202-1207, 1995[4] G. Hua, X. Yang, Y. Jiang, and F.C. Lee, “Novel zero-current-transitionPWM converter”, IEEE Power Electronics Specialist Conf. Rec., pp.538~544, 1993.[5] H. Ohashi, ‘‘Power Electronics Inovation with Next GenerationAdvanced Power Devices’’, Proceeding of INTELEC'03, Oct.2003, Yokohama (Japan), pp.9-13[6] D. M. Divan and G. Skibinski, “Zero switching loss inverters for highpower applications,” IEEE IAS Rec., pp. 627-634, 1987.。

电子信息工程数据库管理中英文对照外文翻译文献

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：数据库管理数据库（有时拼成Database）也称为电子数据库，是指由计算机特别组织的用下快速查找和检索的任意的数据或信息集合。

数据库与其它数据处理操作协同工作，其结构要有助于数据的存储、检索、修改和删除。

数据库可存储在磁盘或磁带、光盘或某些辅助存储设备上。

一个数据库由一个文件或文件集合组成。

这些文件中的信息可分解成一个个记录，每个记录有一个或多个域。

域是数据库存储的基本单位，每个域一般含有由数据库描述的属于实体的一个方面或一个特性的信息。

用户使用键盘和各种排序命令，能够快速查找、重排、分组并在查找的许多记录中选择相应的域，建立特定集上的报表。

数据库记录和文件的组织必须确保能对信息进行检索。

早期的系统是顺序组织的（如:字母顺序、数字顺序或时间顺序）；直接访问存储设备的研制成功使得通过索引随机访问数据成为可能。

用户检索数据库信息的主要方法是query（查询）。

通常情况下，用户提供一个字符串，计算机在数据库中寻找相应的字符序列，并且给出字符串在何处出现。

比如，用户必须能在任意给定时间快速处理内部数据。

而且，大型企业和其它组织倾向于建立许多独立的文件，其中包含相互关联的甚至重叠的数据，这些数据、处理活动经常需要和其它文件的数据相连。

为满足这些要求，开发邮各种不同类型的数据库管理系统，如：非结构化的数据库、层次型数据库、网络型数据库、关系型数据库、面向对象型数据库。

在非结构化的数据库中，按照实体的一个简单列表组织记录；很多个人计算机的简易数据库是非结构的。

层次型数据库按树型组织记录，每一层的记录分解成更小的属性集。

层次型数据库在不同层的记录集之间提供一个单一链接。

与此不同，网络型数据库在不同记录集之间提供多个链接，这是通过设置指向其它记录集的链或指针来实现的。

网络型数据库的速度及多样性使其在企业中得到广泛应用。

当文件或记录间的关系不能用链表达时，使用关系型数据库。

子信息工程(中英文对照)数据仓库正确选择数据采集系统本科学位论文

Selecting the Right Data Acquisition SystemEngineers often must monitor a handful of signals over extended periods of time, and then graph and analyze the resulting data. The need to monitor, record and analyze data arises in a wide range of applications, including the design-verification stage of product development, environmental chamber monitoring, component inspection, benchtop testing and process trouble-shooting.This application note describes the various methods and devices you can use to acquire, record and analyze data, from the simple pen-and-paper method to using today's sophisticated data acquisition systems. It discusses the advantages and disadvantages of each method and provides a list of questions that will guide you in selecting the approach that best suits your needs.IntroductionIn geotechnical engineering, we sometime encounter some difficulties such as monitoring instruments distributed in a large area, dangerous environment of working site that cause some difficulty for easy access. In this case, operators may adopt remote control, by which a large amount of measured data will be transmitted to a observation room where the data are to be collected, stored and processed.The automatic data acquisition control system is able to complete the tasks as regular automatic data monitoring, acquisition and store, featuring high automation, large data store capacity and reliable performance.The system is composed of acquisition control system and display system, with the following features:1. No. of Channels: 32 ( can be increased or decreased according to user's real needs.)2. Scanning duration: decided by user, fastest 32 points/second3. Store capacity: 20G( may be increased or decreased)4. Display: (a) Table of parameter (b) History tendency (c) Column graphics.5. Function: real time monitoring control, warning6. Overall dimension: 50cm×50cm×72cmData acquisition systems, as the name implies, are products and/or processes used to collect information to document or analyze some phenomenon. In the simplest form, a technician logging the temperature of an oven on a piece of paper is performing data acquisition. As technology has progressed, this type of process has been simplified and made more accurate, versatile, and reliable through electronic equipment. Equipment ranges from simple recorders to sophisticated computer systems. Data acquisition products serve as a focal point in a system, tying together a wide variety of products, such as sensors that indicate temperature, flow, level, or pressure. Some common data acquistion terms are shown below:Data acquisition technology has taken giant leaps forward over the last 30 to 40 years. For example, 40 years ago, in a typical college lab, apparatus for tracking the temperature rise in a crucible of sodiumtungsten- bronze consisted of a thermocouple, a bridge, a lookup table, a pad of paper and a pencil.Today's college students are much more likely to use an automated process and analyze the data on a PC Today, numerous options are available for gathering data. The optimal choice depends on several factors, including the complexity of the task, the speed and accuracy you require, and the documentation you want. Data acquisition systems range from the simple to the complex, with a range of performance and functionality.Pencil and paperThe old pencil and paper approach is still viable for some situations, and it is inexpensive, readily available, quick and easy to get started. All you need to do is hook up a digital multimeter (DMM) and begin recording data by hand.Unfortunately, this method is error-prone, tends to be slow and requires extensive manual analysis. In addition, it works only for a single channel of data; while you can use multiple DMMs, the system will quickly becomes bulky and awkward. Accuracy is dependent on the transcriber's level of fastidiousness and you may need to scale input manually. For example, ifthe DMM is not set up to handle temperature sensors, manual scaling will be required. Taking these limitations into account, this is often an acceptablemethod when you need to perform a quick experiment.Strip chart recorderModern versions of the venerable strip chart recorder allow you to capture data from several inputs. They provide a permanent paper record of the data, and because this data is in graphical format, they allow you to easily spot trends. Once set up, most recorders have sufficient internal intelligence to run unattended — without the aid of either an operator or a computer. Drawbacks include a lack of flexibility and relatively low accuracy, which is often constrained to a few percentage points. You can typically perceive only small changes in the pen plots. While recorders perform well when monitoring a few channels over a long period of time, their value can be limited. For example, they are unable to turn another device on or off. Other concerns include pen and paper maintenance, paper supply and data storage, all of which translate into paper overuse and waste. Still, recorders are fairly easy to set up and operate, and offer a permanent record of the data for quick and simple analysis.Scanning digital multimeterSome benchtop DMMs offer an optional scanning capability. A slot in the rear of the instrument accepts a scanner card that can multiplex between multiple inputs, with 8 to 10 channels of mux being fairly common. DMM accuracy and the functionality inherent in the instrument's front panel are retained. Flexibility is limited in that it is not possible to expand beyond the number of channels available in the expansion slot. An external PC usually handles data acquisition and analysis.PC plug-in cardsPC plug-in cards are single-board measurement systems that take advantage of the ISA or PCI-bus expansion slots in a PC. They often have reading rates as high as 100,000 readings per second. Counts of 8 to 16 channels are common, and acquired data is stored directly into the computer, where it can then be analyzed. Because the card is essentially part of the computer, it is easy to set up tests. PC cards also are relatively inexpensive, in part, because they rely on the host PC to provide power, the mechanical enclosure and the user interface. Data acquisition optionsIn the downside, PC plug-in cards often have only 12 bits of resolution, so you can't perceive small variations with the input signal. Furthermore, the electrical environment inside a PC tends to be noisy, with high-speed clocks and bus noise radiated throughout. Often, this electrical interference limits the accuracy of the PC plug-in card to that of a handheld DMM .These cards also measure a fairly limited range of dc voltage. T o measure other input signals, such as ac voltage, temperature or resistance, you may need some sort of external signal conditioning. Additional concerns include problematic calibration and overall system cost, especially if you need to purchase additional signal conditioning accessories or a PC to accommodate the cards. Taking that into consideration, PC plug-in cards offer an attractive approach to data acquisition if your requirements fall within the capabilities and limitations of the card.Data loggersData loggers are typically stand-alone instruments that, once they are setup, can measure, record and display data without operator or computer intervention. They can handle multiple inputs, in some instances up to 120 channels. Accuracy rivals that found in standalone bench DMMs, with performance in the 22-bit, 0.004-percent accuracy range. Some data loggers have the ability to scale measurements, check results against user-defined limits, and output signals for control.One advantage of using data loggers is their built-in signal conditioning. Most are able to directly measure a number of different inputs without the need for additional signal conditioning accessories. One channel could be monitoring a thermocouple, another a resistive temperature device (RTD) and still another could be looking at voltage. Thermocouple reference compensation for accurate temperature measurement is typicallybuilt into the multiplexer cards. A data logger's built-in intelligence helps you set up the test routine and specify the parameters of each channel. Once you have completed the setup, data loggers can run as standalone devices, much like a recorder. They store data locally in internal memory, which can accommodate 50,000 readings or more.PC connectivity makes it easy to transfer data to your computer for in-depth analysis. Most data loggers are designed for flexibility and simple configuration and operation, and many provide the option of remote site operation via battery packs or other methods. Depending on the A/D converter technique used, certain data loggers take readings at a relatively slow rate, especially compared to many PC plug-in cards. Still, reading speeds of 250 readings/second are not uncommon. Keep in mind that many of the phenomena being monitored are physical in nature —such as temperature, pressure and flow —and change at a fairly slow rate. Additionally, because of a data logger's superior measurement accuracy, multiple readings and averaging are not necessary, as they often are in PC plug-in solutions.Data acquisition front endsData acquisition front ends are often modular and are typically connected to a PC or controller. They are used in automated test applications for gathering data and for controlling and routing signals in other parts of the test setup. Front end performance can be very high, with speed and accuracy rivaling the best standalone instruments. Data acquisition front ends are implemented in a number of formats, including VXI versions, such as the Agilent E1419A multifunction measurement and control VXI module, and proprietary card cages.. Although front-end cost has been decreasing, these systems can be fairly expensive, and unless you require the high performance they provide, you may find their price to be prohibitive. On the plus side, they do offer considerable flexibility and measurement capability.Data Logger ApplicationsA good, low-cost data logger with moderate channel count (20 - 60 channels) and a relatively slow scan rate is more than sufficient for many of the applications engineers commonly face. Some key applications include:• Product characterization• Thermal profiling of electronic products• Environmental testing; env ironmental monitoring• Component characterization• Battery testing• Building and computer room monitoring• Process monitoring, evaluation and troubleshooting No single data acquisition system works for all applications. Answering the following questions may help you decide which will best meet your needs:1. Does the system match my application?What is the measurement resolution, accuracy and noise performance? How fast does it scan? What transducers and measurement functions are supported? Is it upgradeable or expandable to meet future needs? How portable is it? Can it operate as a standalone instrument?2. How much does it cost?Is software included, or is it extra? Does it require signal conditioning add-ons? What is the warranty period? How easy and inexpensive is it to calibrate?3. How easy is it to use?Can the specifications be understood? What is the user interface like? How difficult is it to reconfigure for new applications? Can data be transferred easily to new applications? Which application packages are supported?ConclusionData acquisition can range from pencil, paper and a measuring device, to a highly sophisticated system of hardware instrumentation and software analysis tools. The first step for users contemplating the purchase of a data acquisition device or system is to determine the tasks at hand and the desired output, and then select the type and scope of equipmentthat meets their criteria. All of the sophisticated equipment and analysis tools that are available are designed to help users understand the phenomena they are monitoring. The tools are merely a means to an end.正确选择数据采集系统工程师经常要对很长时间内的很多信号进行监测、画图和分析产生的数据。

电子信息工程专业英语写作范文

电子信息工程专业英语写作范文In the realm of electronic information engineering, the art of writing is as crucial as the circuitry itself. It serves as the bridge connecting complex ideas with practical applications.The field demands a clear and concise writing style, ensuring that technical specifications are communicated without ambiguity. Precision is key; a single misplaced word can lead to significant misunderstandings in project implementation.As we delve into the intricacies of electronic systems, writing becomes a tool for documenting research, detailing methodologies, and articulating innovative solutions. It is through well-structured essays that we can convey the subtleties of our work to both peers and laypersons.In crafting an English composition for this discipline, one must consider the audience's technical background. For fellow engineers, the language can be dense with jargon, whereas for a general audience, explanations must be simplified without sacrificing accuracy.The evolution of electronic information engineering is a testament to the power of written communication. From the early days of vacuum tubes to the sophisticated microchips of today, each breakthrough has been documented and sharedthrough the written word.A well-written report not only informs but also inspires. It can ignite the imagination of students, guide the research of professionals, and even influence policy decisions in the tech industry.The future of our discipline hinges on our ability to articulate our ideas effectively. As we continue to push the boundaries of what is possible, our writing must evolve to match the complexity and innovation of our work.In conclusion, the role of English writing in electronic information engineering is multifaceted. It is a means of communication, a tool for documentation, and a catalyst for progress. As we refine our craft, we contribute to the ongoing dialogue that shapes the technological landscape.。

电子信息类英文资料加翻译

电子信息类英文资料加翻译Sequential Logic Test1.1 INTRODUCTIONThe previous chapter examined methods for creating sensitized paths in combina-tional logic extending from stuck-at faults on logic gates to observable outputs. Wenow attempt to create tests for sequential circuits where the outputs are a functionnot just of present inputs but of past inputs as well. The objective will be the same:to create a sensitized path from the point where a fault occurs to an observable out-put. However, there are new factors that must be taken into consideration. A sensi-tized path must now be propagated not only through logic operators, but also through an entirely new dimension—time. The time dimension may be discrete, asin synchronous logic, or it may be continuous, as in asynchronous logic.The time dimension was ignored when creating tests for faults in combinationallogic.It was implicitlyassu med that the output response would stabilize before being measured with test equipment, and it was generally assumed that each test pat-tern was independent of its predecessors. As will be seen, the effects of time cannotbe ignored, because this added dimension greatly inﬂuences the results of test pat-tern generation and can complicate, by orders of magnitude, the problem of creatingtests. Assumptions about circuit behavior must be carefully analyzed to determinethe circumstances under which they prevail.1.2 TEST PROBLEMS CAUSED BY SEQUENTIAL LOGIC Two factors complicate the task of creating tests for sequential logic: memory andcircuit delay. In sequential circuits the signals must not only be logically correct, butmust also occur in the correct time sequence relative to other signals. The test prob-lem is further complicated by the fact that aberrant behavior can occur in sequentialcircuits when individual discrete components are all fault-free and conform to theirmanufacturer’s speciﬁcations. We ﬁrst consider problems caused by the presence ofmemory, and then we examine the effects of circuit delay on the test generation problem.1.2.1 The Effects of MemoryIn the ﬁrst chapter it was pointed out that, for combinational circuits, it was possible(but not necessarily reasonable) to create a complete test for logic faults by applyingall possible binary combinations to the inputs of a circuit. That, as we shall see, is not true for circuits with memory. They may not only require more than 2 tests, butare also sensitive to the order in which stimuli are applied.Test Vector Ordering The effects of memory can be seen from analysis of thecross-coupled NAND latch [cf. Figure 2.3(b)]. Four faults will be considered, thesebeing the input SA1 faults on each of the two NAND gates (numbering is from topto bottom in the diagram). All four possible binary combinations are applied to theinputs in ascending order—that is, in the sequence (Set, Reset) = {(0,0), (0,1), (1,0),(1,1)}. We get the following response for the fault-free circuit (FF) and the circuit corresponding to each of the four input SA1 faults.InputOutputSet Reset FF 1 2 340 0 1 0 1 110 1 1 0 1 111 0 0 0 0 011 1 0 0 0 11In this table, fault number 2 responds to the sequence of input vectors with an outputresponse that exactly matches the fault-free circuit response. Clearly, this sequenceof inputs will not distinguish between the fault-free circuit and a circuit with input 2SA1.The sequence is now applied in the exact opposite order. We get:Input OutputSet Reset FF 1 2 341 1 ? ? 01 ?1 0 0 0 00 ?0 1 1 0 1 110 0 1 0 1 11The Indeterminate Value When the four input combinations are applied in reverse order, question marks appear in some table positions. What is their signiﬁ-cance? To answer this question, we take note of a situation that did not exist whendealing only with combinational logic; the cross-coupled NAND latch has memory.By virtue of feedback present in the circuit, it is able to remember the value of a sig-nal that was applied to the set input even after that signal is removed.Because of the feedback, neither the Set nor the Reset line need be held low anylonger than necessary to effectively latch the circuit. However, when power is ﬁrstapplied to the circuit, it is not known what value is contained in the latch. How cancircuit behavior be simulated when it is not known what value is contained in its memory?In real circuits, memory elements such as latches and ﬂip-ﬂops have indetermi-nate values when power is ﬁrst applied. The contents of these elements remain indeterminate until the latch or ﬂip-ﬂop is either set or reset to a known value. In asimulation model this condition is imitated by initializing circuit elements to the indeterminate X state. Then, as seen in Chapter 2, some signal values can drive a logic element to a known state despite the presence of indeterminate values on other inputs. For example, the AND gate in Figure 2.1(c) responds with a 0 when any single input receives a 0, regardless of what values are present on other inputs. However, if a 1 is applied while all other inputs are at X, the output remains at X.Returning to the latch, the ﬁrst sequence began by applying 0s to both inputs,while the second sequence began by applying 1s to both inputs. In both cases the internal nets were initially indeterminate. The 0s in the ﬁrst sequence were able todrive the latch to a known state, making it possible to immediately distinguishbetween correct and incorrect response. When applying the patterns in reverse order,it took longer to drive the latch into a state where good circuit response could be dis-tinguished from faulty circuit response. As a result, only one of the four faults is detected, namely, fault 1. Circuits with faults 2 and 3 agree with the good circuit response in all instances where the good circuit has a known response. On the ﬁrstpattern the good circuit respons is indeterminate and the circuit with fault 2responds with a 0. The circuit with fault 3 responds with a 1. Since it is not knownwhat value to expect from the good circuit, there is no way to decide whether the faulted circuits are responding correctly.Faulted circuit 4 presents an additional complication. Its response is indetermi-nate for both the ﬁrst and second patterns. However, because the good circuit has aknown response to pattern 2, we do know what to look for in the good circuit, namely, the value 0. Therefore, if a NAND latch is being tested with the second setof stimuli, and it is faulted with input 4 SA1, it might come up initially with a 0 onits output when power is applied to the circuit, in which case the faul is not detected, or it could come up with a 1, in which case the fault will be detected. Oscillations Another complication resulting from the presence of memory is oscillations. Suppose that we ﬁrst apply the test vector (0,0) to the cross-coupled NAND latch. Both NAND gates respond with a logic 1 on their outputs. We then apply the combination (1,1) to the inputs. Now there are 1s on both inputs to each ofthe two NAND gates—but not for long. The NAND gates transform these 1s into 0son the outputs. The 0s then show up on the NAND inputs and cause the NAND out-puts to go to 1s. The cycle is repetitive; the latch is oscillating. We do not know whatvalue to expect on the NAND gate outputs; the latch may continue to oscillate until adifferent stimulus is applied to the inputs or the oscillations may eventually subsideIf the oscillations do subside, there is no practical way to predict, from a logic description of the circuit, the ﬁnal state into which the latch settles. Therefore, theNAND outputs are set to the indeterminate X.Probable Detected Faults When we analyzed the effectivenes of binary sequences applied to the NAND latch in descending order, we could not claimwithcertainty that stuck-at fault number 4 would be detected. Fortunately, that fault isdetected when the vectors are applied in ascending order. In other circuits the ambi-guity remains. In Figure 2.4(b) the Data input is complemented and both true andcomplement values are applied to the latch. Barring the presence of a fault, the latchwill not oscillate. However, when attempting to create a test for the circuit, we encounter another problem. If the Enable signal is SA1, the output of the inverterdriven by Enable is permanently at 0 and the NAND gates driven by the inverter arepermanently in a 1 state; hence the faulted latch cannot be initialized to a known state. Indeterminate states were set on the latch nodes prior to the start of test patterngeneration and the states remain indeterminate for the faulted circuit. If power is applied to the fault-free and faulted latches, the circuits may just happen to come upin the same state.The problem just described is inherent in any ﬁnite-state machine (FSM). TheFSM is characterized by a set of states Q = {q , q , ..., q }, a set of input stimuli1 2 sI = {i , i , ..., i }, another set Y = {y , y , ..., y } of output responses, and a pair of1 2 n 1 2 m Mappings M : Q × I → QZ : Q × I → YThese mappings deﬁne the next state transition and the output behav ior in responseto any particular input stimulus. These mappings assume knowledge of the currentstate of the FSM at the time the stimulus is applied. When the initial stimulus is applied, that state is unknown unless some independent means such as a reset existsfor driving the FSM into a known state.In general, if there is no independent means for initializing an FSM, and if theClock or Enable input is faulty, then it is not possible to apply just a single stimu-lus to the FSM and detect the presence of that fault. One approach used in industryis to mark a fault as a probable detect if the fault-free circuit drives an output pinto a known logic state and the fault causes that same pin to assume an unknown state.The industry is not in complete agreement concerning the classiﬁcation of proba-ble detected faults. While some test engineers maintain that such a fault is likely toeventually become detected, others argue that it should remain classiﬁed as undetec-ted, and still others prefer to view it as a probable detect. If the probable detectedfault is marked as detected, then there is a concern that an ATPG may be designed toignore the fault and not try to create a test for it in those situations where a test exists.The Initialization Problem Consider the circuit of Figure 5.1. During simula- tion, circuit operation begins with the D ﬂip-ﬂop in an unknown state. In normal operation, when the input combination A = B = C = 0 is applied and the ﬂip-ﬂop isclocked, the Q output switches to 0. The ﬂip-ﬂop can then be clocked a second timeto obtain a test for the lower input of gate 3 SA1. If it is SA1, the expected value isQ = 1; and if it is fault-free, the expected value is Q = 0.Unfortunately, the test has a serious ﬂaw! If the lower input to gate 3 is SA1, theoutput of the ﬂip-ﬂop at the end of the ﬁrst clock period is indeterminate because thevalue at the middle input to gate 3 is initially indeterminate. It is driven by the ﬂip-ﬂop that has an indeterminate value. After a second clock pulse the value at Q willremain at X; hence it may agree with the good circuit response despite the presenceof the fault. The fallacy lies in assuming correct circuit behavior when setting up theﬂip-ﬂop for the test. We depended upon correct behavior of the very net that we areattempting to test when setting up a test to detect a fault on that net.To correctly establish a test, it is necessary to assume an indeterminate value fromthe ﬂip-ﬂop. Then, from the D-algorithm, we know that the ﬂip-ﬂop must be driveninto the 0 state, without depending on the input to gate 3 that is driven by the ﬂip-ﬂop. The ﬂip-ﬂop v alue can then be used in conjunction with the inputs to test for the SA1 on the lower input of gate 3. In this instance, we can set A = C = 0, B = 1. Then a 1 can be clocked into the ﬂip-ﬂop from gate 2. This produces a 0 on the out-put of the ﬂip-ﬂop which can then be used with the assignment A = B = 0 to clock a0 into the ﬂip-ﬂop. Now, with Q = 0 and A = B = C = 0, another clock causes D to appear on the output of the ﬂip-ﬂop.Notice that input C was used, but it was used to set up gate 2. If input C werefaulted in such a way as to affect both gates 2 and 3, then it could not have been usedto set up the test.1.2 .2 Timing ConsiderationsUntil now we have assumed that erroneous behavior on circuit outputs was the result of logic faults. Those faults generall result from actual physical defects such as opens or shorts, or incorrect fabrication such as an incorrect connection or a wrong component. Unfortunately, this assumption, while convenient, is an oversimpliﬁca- tion. An error may indeed be a result of one or more logic faults, but it may also be the case that an error occurs and none of the above situations exists.Defects exist that can prevent an element from behaving in accordance with its speciﬁcations. Faults that affect the performance of a circuit are referred to as para- metric faults, in contrast to the logic faults that have been considered up to this point. Parametric faults can affect voltage and current levels, and they can affect gain and switching speed of a circuit. Parametric faults in components can result from improper fabrication or from degradation as a consequence of a normal aging process. Environmental conditions such as temperature extremes, humidity, or mechanical vibration can accelerate the degradation process.Design oversights canproduce symptoms similar to parametric faults. Design problems include failure to take into account wire lengths, loading of devices, inad- equate decoupling, and failure to consider worst-case conditions such as maximum or minimum voltages or temperatures over which a device may be required to oper- ate. It is possible that none of these factors may cause an error in a particular design in a well-controlled environment, and yet any of these factors can destabilize a cir- cuit that is operating under adverse conditions. Relative timing between signal paths or the ability of the circuit to drive other circuits could be affected.Intermit tenterrors are particularly insidious because of their rather elusive nature, appearing only under particular combinations of circumstances. Forexam-ple, a logic board may be designed for nominal signal delay for each component as asafety margin. Statistically, the delays should seldom accumulate so as to exceed acritical threshold. However, as with any statistical expectation, there will occasion-ally be a circuit that does exceed the maximum permissible value. Worse still, it maywork well at nominal voltages and /or temperatures and fail only when voltages and/or temperatures stray from their nominal value. A new board substituted for the orig-inal board may be closer to tolerance and work well under the degraded voltage and or temperature conditions. The original board may then, when checked at a depot or a board tester under ideal operating conditions, test satisfactorily.Consider the effects of timing variations on the delay ﬂip-ﬂop of Figure 2.7. Cor-rect operation of the ﬂip-ﬂop requires that the designer observe minimal setup andhold times. If propagation delay along a signal path to the Data input of the ﬂip-ﬂopis greater than estimated by the designer, or if parametric faults exist, then the setuptime require ment relative to the clock may not be satisﬁed, so the clock attempts tolatch the signal while it is still changing. Problems can also occur if a signal arrivestoo soon. The hold time requirement will be violated if a new signal value arrives atthe d ata input before the intended value is latched up in the ﬂip-ﬂop. This can hap-pen if one register directly feeds another without any intervening logic.That logic or parametric faults can cause erroneous operation in a circuit is easyto understand, but digital test problems are further compounded by the fact thaterrors can occur during operation of a device when it components behave as intended. Elements used in the fabrication of digital logic circuits contain delay.Ironically, although technologists constantly try to create faster circuits and reducedelay, sequential logic circuits cannot function without delay; circuits depend both on correct logic operation of circuit components and on correct relativetiming ofsignals passing through the circuit. This delay must be taken into account when designing and testing circuits.Suppose the inverter driven by the Data input in the gated latch circuit ofFigure 2.4(b) has a delay of n nanoseconds. If the Data input makes a 0-to-1 transi-tion followed by a 0-to-1 transition on the Enable approximately n nanoseconds later, the two cross-coupled NAND gates see an input of (0,0) for about n nanosec-onds followed by an input of (1,1). This produces unpredictable results, as we haveseen before. The problem is caused by the delay in the inverter. A solution to this problem is to put a buffer in the noninverting signal path so the Data and Data sig-nals reach the NANDs at about the same time.In each of the two circuits just cited, the delay ﬂip-ﬂop and the latch, a race exists. A race is a condition wherein two or more signals are changing simulta-neously in a circuit. The race may be caused by multiple simultaneous input signalchanges, or it may be the result of a single signal change that follows two or more paths from a fanout point. Note that any time we have a latch or ﬂip-ﬂop we have arace condition, since these devices will always have at least one element whose sig-nal both goes outside the device and feeds back to an input of the latch or ﬂip-ﬂop.Races may or may not affect the behavior of a circuit. A critical race exists if the behavior of a circuit depends on the outcome of the race. Such races can produce unanticipated and unwanted results.Hazards can also cause sequential circuits to behave in ways that were not sidered. Like timing problems, hazards can be extremely difﬁcult to diagnose because their effect on a circuit may depend on other factors, such as marginal volt-ages or an operating temperature that is within speciﬁcation but borderline. Underoptimal conditions, a glitch caused by a hazard may not contain enough energy tocause a latch to switch state; but under the inﬂuence of marginal operating condi-tions, this glitch may have sufﬁcient energy to cause a latch of ﬂip-ﬂop to switch states.顺序逻辑测试1.1介绍前一章检查方法在结合创建敏化的路径——从固定逻辑，传统逻辑，扩展逻辑门上的断层,可观察到的输出。

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