刘飞毕业设计(论文)外文翻译译文

大连东软信息学院
毕业设计（论文）外文资料及译文
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大连东软信息学院
Dalian Neusoft University of Information
外文资料和译文格式要求
一、装订要求
1、外文资料原文（复印或打印）在前、译文在后、最后为指导教师评定成绩。

2、译文必须采用计算机输入、打印。

3、A4幅面打印，于左侧装订。

二、撰写要求
1、外文文献内容与所选课题相关。

2、本科学生译文汉字字数不少于4000字，高职学生译文汉字字数不少于2000字。

三、格式要求
1、译文字号：中文小四号宋体，英文小四号“Times New Roman”字型，全文统一，首行缩进2个中文字符，1.5倍行距。

2、译文页码：页码用阿拉伯数字连续编页，字体采用“Times New Roman”字体，字号小五，页底居中。

3、译文页眉：眉体使用单线，页眉说明五号宋体，居中“大连东软信息学院本科毕业设计（论文）译文”。

译文模型飞机设计介绍这种教学系列是书面与应用专业的飞机设计原则，以简单的无线电控制的飞机设计的水平，可以使学生易于理解。

学习模块可以依次写入，也可以单独引用。

此教学系列涵盖了许多不同的设计方面。

但是学习模块并非很详细，许多课题已省略，因为它们太复杂，难于处理，或对于简单模型飞机的设计它们的影响是微不足道的。

学习模块是休闲的，以对话式参与读者的方式，使内容更容易被非专业的读者所理解。

教师计划使用这些学习模块可以让读者自己阅读和适应课程，或者使他们以学生的角度去学习。

这是老师的决定，因为他们知道他们的学生需要学习什么，什么是适合他们课程计划和课程内容的。

各种深度的概念已被添加在学习单元的结尾。

这些可能包括复杂的飞机设计，或者更先进的数学技术。

飞机设计涵盖了众多的学科，从创意、艺术灵感、精确的数学计算，以及先进的理念帮助，以满足更广泛的教育需求。

在这里，有些学生可能会比别人提出更多的议题，并可能要继续学习飞机设计。

在指南的最后一个进一步阅读的部分已经提供了指向在线资源和印刷文本，学生可以自主学习。

也有一些建议项目学生可以学习，无论是独立或作为SACE研究项目的一部分。

大学生可能提供帮助指导学生学习，而这会给中学生学习的机会，通常在高年级本科生和硕士学位发现的研究课题。

这本手册的计划和指示，建立了两个无线电控制的飞机，在山谷景观ACE和额外的300 部。

这些文件包含建立和飞这架飞机所需的信息。

这种教学系列被写入到需要这些信息，并允许扩展，但仅靠这种教学系列是不足以建立一个无线电控制的飞机，作为构建技术和一些特定的信息没有被提供。

这个信息很容易在互联网上，有些链接会在进一步阅读环节里。

学习模块1飞机怎样飞行？基础知识让我们以一个客机开始，例如波音737，从阿德莱德飞往墨尔本。

我们忽略它的起飞和降落，来看它的主要部分“巡航”在这个期间，飞机没有更快或者更慢，也没有变高变低，没有左右转弯，只是保持一个速度平直飞行。

轨道交通学院毕业设计（论文）外文翻译题目：列车车载的直流恒流源的设计专业电子信息工程班级10115111学号1011511137姓名赵士伟指导教师陈文2014 年3 月 3 日本文摘自：IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS VOL. IGA-2, NO.5 SEPT/OCT 1966Highly Regulated DC Power Supplies Abstract-The design and application of highly regulated dc power supplies present many subtle, diverse, and interesting problems. This paper discusses some of these problems (especially inconnection with medium power units) but emphasis has been placed more on circuit economics rather than on ultimate performance.Sophisticated methods and problems encountered in connection with precision reference supplies are therefore excluded. The problems discussed include the subjects of temperature coefficient,short-term drift, thermal drift, transient response degeneration caused by remote sensing, and switching preregualtor-type units and some of their performance characteristics.INTRODUCTIONANY SURVEY of the commercial de power supply field will uncover the fact that 0.01 percent regulated power supplies are standard types and can be obtained at relatively low costs. While most users of these power supplies do not require such high regulation, they never-theless get this at little extra cost for the simple reason that it costs the manufacturer very little to give him 0.01 percent instead of 0.1 percent. The performance of a power supply, however, includes other factors besides line and load regulation. This paper will discuss a few of these-namely, temperature coefficient, short-term drift, thermal drift, and transient response. Present medium power dc supplies commonly employ preregulation as a means of improving power/volume ratios and costs, but some characteristics of the power supply suffer by this approach. Some of the short-comings as well as advantages of this technology will be examined.TEMPERATURE COEFFICIENTA decade ago, most commercial power supplies were made to regulation specifications of 0.25 to 1 percent. The reference elements were gas diodes having temperature coefficients of the order of 0.01 percent [1]. Consequently, the TC (temperature coefficient) of the supply was small compared to the regulation specifications and often ignored. Today, the reference element often carries aTC specification greater than the regulation specification.While the latter may be improved considerably at little cost increase, this is not necessarily true of TC. Therefore,the use of very low TC zener diodes, matched differential amplifier stages, and low TC wire wound resistors must be analyzed carefully, if costs are to be kept low.A typical first amplifier stage is shown in Fig. 1. CRI is the reference zener diode and R, is the output adjustment potentiometer.Fig. 1. Input stage of power supply.Fig. 2. Equivalent circuit of zener reference.Let it be assumed that e3, the output of the stage, feedsadditional differential amplifiers, and under steady-state conditions e3 = 0. A variation of any of the parameters could cause the output to drift; while this is also true of the other stages, the effects are reduced by the gain of all previous stages. Consequently, the effects of other stages will be neglected. The following disculssion covers the effects of all elements having primary and secondary influences on the overall TC.Effect of R3The equivalent circuit of CRI -R3 branch is shown in Fig. 2. The zener ha's been replaced with its equivalent voltage source E/' and internal impedance R,. For high gain regulators, the input of the differential amplifier will have negligible change with variations of R3 so thatbefore and after a variation of R3 is made.If it is further assumed that IB << Iz; then from (1)Also,Eliminating I, from (2b),andNow, assuming thatthen,Equation (2b) can also be writtenThe Zener DiodeThe zener diode itself has a temperature coefficient andusually is the component that dominates the overall TCof the unit. For the circuit of Fig. 1, the TC ofthe circuit describes, in essence, the portion of the regulator TC contributed by the zener. If the bridge circuit shown in Fig. 1 were used in conjunction with a dropping resistor so that only a portion of the output voltage appeared across the bridge circuit shown, the TC of the unit and the zener would be different. Since the characteristic of zeners is so well known and so well described in the literature, a discussion will not be given here [2].Variation of Base-Emitter VoltagesNot only do the values of V,, of the differential am-plifier fail to match, but their differentials with tem perature also fail to match. This should not, however,suggest that matched pairs are required. The true reference voltage of Fig. 1 is not the value E,, but E, + (Vie, -Vbe2)-Since, for most practical applicatioinsthe TC of the reference will be the TC of the zener plusConsidering that it is difficult to obtain matched pairs that have differentials as poor as 50 V/°C, it becomes rather apparent that, in most cases, a matched pair bought specifically for TC may be overdesigning.Example 2: A standard available low-cost matched pair laims 30AV/°C. In conjunction with a 1N752, the ontribution to the overall TC would beTests, performed by the author on thirteen standard germanium signal transistors in the vicinity of room temperature and at a collector current level of 3 mA,indicated that it is reasonable to expect that 90 to 95 percent of the units would have a base-emitter voltage variation of -2.1 to -2.4 mV/°C. Spreads of this magnitude have also been verified by others (e.g., Steiger[3]). The worst matching of transistors led to less than 400 ,V/°C differential. In conjunction with a 1N752,even this would give a TC of better than 0.007%/0C.Variation of Base CurrentsThe base current of the transistors is given byA variation of this current causes a variation in signal voltage at the input to the differential amplifier due to finite source impedances. Matching source impedances is not particularly desirable, since it reduces the gain of the system and requires that transistors matched for I,o and A be used. Hunter [4 ] states that the TC of a is in the range of +0.2%/0C to -0.2%7/'C and that 1,, may be approximated bywhere Ao is the value at To.β is also temperature dependent and Steiger [3] experimentally determined the variation to be from about 0.5%/°C to 0.9%/0C.And，Fig. 3. Input circuit of Q2.The current AIB flows through the source impedance per Fig. 3. The drops in the resistance string, however, are subject to the constraint that EB (and AEB) are determined by the zener voltage and the base-emitter drops of Q1 and Q2. Consequently, if in going from temperature T1to T2 a change AEB occurs,The change in output voltage isAndExample 3: For Q2 (at 25°C)(see Example 1)∴Variation of R,The effects of a variation of the TC between RIA and RIB is sufficiently self-evident so that a discussion of the contribution is not included.SHORT-TERM DRIFTThe short-term drift of a supply is defined by the National Electrical Manufacturers Association (NEMA) as "a change in output over a period of time, which change is unrelated to input, environment, or load [5]."Much of the material described in the section on temperature coefficient is applicable here as well. It has been determined experimentally, however, that thermal air drafts in and near thevicinity ofthe powersupplycontributesenormouslyto theshort-termcharacteristics. Thecooling effects of moving air are quite well known, but it is not often recognized that even extremely slow air movements over such devices as zeners and transistors cause the junction temperature of these devices to change rapidly. If the TC of the supply is large compared to the regulation, then large variations in the output will be observed. Units having low TC's achieved by compensation-that is, by canceling out the effects of some omponents by equal and opposite effects of others may still be plagued by these drafts due to the difference in thermal time constants of the elements.Oftentimes, a matched transistor differential amplifier in a common envelope is used for the first amplifier just to equalize and eliminate the difference in cooling effects between the junctions. Approximations to this method include cementing or holding the transistors together, imbedding the transistors in a common metal block, etc. Excellent results were achieved by the author by placing the input stage and zener reference in a separate enclosure. This construction is shown in Fig. 4. The improvement in drift obtained by means of the addition of the metal cover is demonstrated dramatically in Fig. 5.Fig. 5. Short-term drift of a power supply similar to the one shown in Fig. 4 with and without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to a temperaturerise inside the box.Fig. 5. Short-term drift of a power supply similar to the one shown n Fig. 4 withand without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to atemperature rise inside the box.If potentiometers are used in the supply for output adjustment (e.g., RI), care should be used in choosing the value and design. Variations of the contact resistance can cause drift. It is not always necessary, however, to resort to the expense of high-resolution multiturn precision units to obtain low drift. A reduction in range of adjustment, use of low-resistance alloys and low-resolution units which permit the contact arm to rest firmly between turns, may be just as satisfactory. Of course, other considerations should include the ability of both the arms and the wire to resist corrosion. Silicone greases are helpful here. Periodic movement of contact arms has been found helpful in "healing" corroded elements.THERMAL DRIFTNEMA defines thermal drift as "a change in output over a period of time, due to changes in internal ambient temperatures not normally related to environmental changes. Thermal drift is usually associated with changes in line voltage and/or load changes [5]."Thermal drift, therefore, is strongly related to the TC of the supply as well as its overall thermal design. By proper placement of critical components it is possible to greatly reduce or even eliminate the effect entirely. It is not uncommon for supplies of the 0.01 percent(regulation) variety to have drifts of between 0.05 to 0.15 percent for full line or full load variations. In fact, one manufacturer has suggested that anything better than 0.15 percent is good. Solutions to reducing thermal drift other than the obvious approach of improving the TC and reducing internal losses include a mechanical design that sets up a physical and thermal barrier between the critical amplifier components and heat dissipating elements. Exposure to outside surfaces with good ventilation is recommended. With care, 0.01 to 0.05 percent is obtainable.TRANSIENT RESPONSEMost power supplies of the type being discussed have a capacitor across the load terminals. This is used for stabilization purposes and usually determines the dominant time constant of the supply. The presence of this capacitor unfortunately leads to undesirable transient phenomena when the supply is used in the remote sensing mode①. Normally, transistorized power supplies respond in microseconds, but as the author has pointed out [6], the response can degenerate severely in remote sensing .The equivalent circuit is shown in Fig. 6. The leads from the power supply to the load introduce resistance r. Is is the sensing current of the supply and is relatively constant.Under equilibrium conditions,A sudden load change will produce the transient of Fig. 7. The initial "spike" is caused by an inductive surge Ldi/dt; the longer linear discharge following is the resultof the capacitor trying to discharge (or charge). The discharge time iswhereandThe limitations of I,, are usually not due to available drive of the final amplifier stages but to other limitations, current limiting being the most common. Units using pre regulators of the switching type (transistor or SCR types) should be looked at carefully if the characteristics mentioned represent a problem.①Remote sensing is the process by which the power supply senses voltage directly at the load.Fig. 6. Output equivalent circuit at remote sensing.Fig. 7. Transient response, remote sensing.Fig. 8. Block diagram.Preregulated supplies are used to reduce size and losses by monitoring and controlling the voltage across the class-A-type series passing stage (Fig. 8). Since the main regulator invariably responds much quicker than the preregulator, sufficient reserve should always be built into the drop across the passing stage. Failure to provide this may result in saturation of the passing stage when load is applied, resulting in a response time which is that of the preregulator itself.SWITCHING PREREGULATOR-TYPE UNITS The conventional class-A-type transistorized power supply becomes rather bulky, expensive, and crowded with passing stages, as the current and power level of the supply increases. The requirement of wide output adjustment range, coupled with the ability of the supply to be remotely programmable, aggravates the condition enormously. For these reasons the high-efficiency switching regulator has been employed as a preregulator in commercial as well as military supplies for many years. The overwhelming majority of the supplies used silicon controlled rectifiers as the control element. For systems operating from 60-cycle sources, this preregulator responds in 20 to 50 ms.Recent improvements in high-voltage, high-power switching transistors has made the switching transistor pproach more attractive. This system offers a somewhat lower-cost, lower-volume approach coupled with a submillisecond response time. This is brought about by a high switching rate that is normally independent of line frequency. The switching frequency may be fixed, a controlled variable or an independent self-generated (by the LC filter circuit) parameter [7], [8]. Faster response time is highly desirable since it reduces the amount of reserve voltage required across the passing stage or the amount of (storage) capacity required in the preregulator filter.A transistor suitable for operating as a power switch has a high-current, high-voltage rating coupled with low leakage current. Unfortunately, these characteristics are achieved by a sacrifice in thermal capacity, so that simultaneous conditions of voltage and current leading to high peak power could be disastrous. It therefore becomes mandatory to design for sufficient switch drive during peak load conditions and also incorporate current-limiting or rapid overload protection systems.Commercial wide-range power supplies invariably have output current limiting, but this does not limit the preregulator currents except during steady-state load conditions (including short circuits). Consider, for example, a power supply operating at short circuit and the short being removed suddenly. Referring to Fig. 8, the output would rise rapidly, reduce the passing stage voltage, and close the switching transistor. The resulting transient extends over many cycles (switching rate) so that the inductance of the preregulator filter becomes totally inadequate to limit current flow. Therefore, the current will rise until steady state is resumed, circuit resistance causes limiting, or insufficient drive causes the switch to come out of saturation. The latter condition leads to switch failure.Other operating conditions that would produce similar transients include output voltage programming and initial turn-on of the supply. Momentary interruption of input power should also be a prime consideration.One solution to the problem is to limit the rate of change of voltage that can appear across the passing stage to a value that the preregulator can follow. This can be done conveniently by the addition of sufficient output capacitance. This capacitance inconjunction with the current limiting characteristic would produce a maximum rate of change ofwhereC0 = output capacity.Assuming that the preregulator follows this change and has a filter capacitor Cl, then the switch current isDuring power on, the preregulator reference voltage rise must also be limited. Taking this into account,whereER = passing stage voltageTl = time constant of reference supply.The use of SCR's to replace the transistors would be a marked improvement due to higher surge current ratings, but turning them off requires large energy sources. While the gate turn-off SCR seems to offer a good compromise to the overall problem, the severe limitations in current ratings presently restrict their use.REFERENCES[1] J. G. Truxal, Control Engineer's Handbook. New York: McGrawHill, 1958, pp. 11-19.[2] Motorola Zener Diode/Rectifier Handbook, 2nd ed. 1961.[3] W. Steiger, "A transistor temperature analysis and its applica-tion to differential amplifiers," IRE Trans. on Instrumentation,vol. 1-8, pp. 82-91, December 1959.[4] L. P. Hunter, Handbook of Semi-Conductor Electronics. NewYork: McGraw Hill, 1956, p. 13-3.[5] "Standards publication for regulated electronic dc powersupplies," (unpublished draft) Electronic Power Supply Group,Semi-Conductor Power Converter Section, NEMA.[6] P. Muchnick, "Remote sensing of transistorized power sup-plies," Electronic Products, September 1962.[7] R. D. Loucks, "Considerations in the design of switching typeregulators," Solid State Design, April 1963.[8] D. Hancock and B. Kurger, "High efficiency regulated powersupply utilizing high speed switching," presented at the AIEEWinter General Meeting, New York, N. Y., January 27-February 1, 1963.[9] R. D. Middlebrook, Differential Amplifiers. New York: Wiley,1963.[10] Sorensen Controlled Power Catalog and Handbook. Sorensen,Unit of Raytheon Company, South Norwalk, Conn.With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equipment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin, small and efficient for development direction. The traditional transistors series adjustment manostat is continuous control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency transformer and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of its small volume, light weight, high efficiency, wide range, voltage advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics, electrical equipment, home appliances areas to be widely, switch power technology into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Power switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhances unceasingly, improving efficiency, and for power miniaturization provides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power IC development. Adopt TOP switch IC design switch power, can make the circuit simplified, volume further narrowing, cost also is decreased obviouslyMonolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power supply, etc. American PI (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the "top switch Power", with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 series, the second generation product is the TOPSwitch - debuted in 1997 Ⅱ. The above products once appeared showed strong vitality and he greatly simplifies thedesign of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost switch power supply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price can compete with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials, no new breakthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of digital control IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels haven't seen practicability of the method appears particularly strong,perhaps with the popularity of digital control, and there are some new control theory into switching power supply.（1）The technology: with high frequency switching frequencies increase, switch converter volume also decrease, power density has also been boosted, dynamic response improved. Small power DC - DC converter switch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused.（2）Soft switching technologies: in order to improve the efficiency ofnon-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zero voltage/zero current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation efficiency （3）Power factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IC simplifies PFC technology can improve AC - DC change device input power factor, reduce the harmonic pollution of power grid.（4）Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.（5）Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocessor and portable electronic devices work more and more low, this requires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power electronics device, the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching powersupply can be divided into the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the process of making modular, meet more complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noise, anti-jamming and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, and power loss of Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power supply has made considerable progress, both sides in the circuitboard to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has becomethe mainstream of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, America's switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliability of products made greatly increased.Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise this one defect, if separate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a technical problem, so in this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in China, we must walk speed of technological innovation road, combination with Chinese characteristics in the joint development path, for I the high-speed development of national economy to make the contribution. The basic principle and component functionAccording to the control principle of switch power to classification, we have the following 3 kinds of work mode:1) pulse width adjustment type, abbreviation Modulation PulseWidth pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the purpose. Its core is the pulse width modulator. Switch cycle for designing filter circuit fixed provided convenience. However, its shortcomings is influenced by the power switch conduction time limit minimum of output voltage cannot be wide range regulation; In addition, the output will take dummy loads commonly (also called pre load), in order to prevent the drag elevated when output voltage. At present, most of the integrated switch power adopt PWM way.2) pulse frequency Modulation mode pulse frequency Modulation (, referred to PulseFrequency Modulation, abbreviation for PFM) type. Its characteristic is will pulse width fixed by changing switch frequency to adjust voltage 390v, realize the purpose. Its core is the pulse frequency modulator. Circuit design to use fixed pulse-width generator to replace the pulse width omdulatros and use sawtooth wave generator voltage? Frequency converter (for example VCO changes frequency VCO). It on voltage stability principle is: when the output voltage Uo rises, the output signal controller pulse width unchanged and cycle longer, make Uo 390v decreases, and reduction. PFM type of switch power supply output voltage range is very wide, output terminal don't meet dummy loads. PWM way and way of PFM respectively modulating waveform is shown in figure 1 (a), (b) shows, tp says pulse width (namely power switch tube conduction time tON), T represent cycle. It can be easy to see the difference between the two. But they have something in common: (1) all use time ratio control (TRC) on voltage stability principle, whether change tp, finally adjustment or T is。

本科生毕业设计（论文）外文科技文献译文译文题目(外文题目)学院(系)Socket网络编程的设计与实现A Design andImplementation of Active Network Socket Programming机械与能源工程学院专学业号机械设计制造及其自动化071895学生姓名李杰林日期2012年5月27日指导教师签名日期摘要：编程节点和活跃网络的概念将可编程性引入到通信网络中，并且代码和数据可以在发送过程中进行修改。

最近，多个研究小组已经设计和实现了自己的设计平台。

每个设计都有其自己的优点和缺点，但是在不同平台之间都存在着互操作性问题。

因此，我们引入一个类似网络socket编程的概念。

我们建立一组针对应用程序进行编程的简单接口，这组被称为活跃网络Socket编程（ANSP）的接口，将在所有执行环境下工作。

因此，ANSP 提供一个类似于“一次性编写，无限制运行”的开放编程模型，它可以工作在所有的可执行环境下。

它解决了活跃网络中的异构性，当应用程序需要访问异构网络内的所有地区，在临界点部署特殊服务或监视整个网络的性能时显得相当重要。

我们的方案是在现有的环境中，所有应用程序可以很容易地安装上一个薄薄的透明层而不是引入一个新的平台。

关键词：活跃网络；应用程序编程接口；活跃网络socket编程1 导言1990年，为了在互联网上引入新的网络协议，克拉克和藤农豪斯[1]提出了一种新的设计框架。

自公布这一标志性文件，活跃网络设计框架[2，3，10]已经慢慢在20世纪90 年代末成形。

活跃网络允许程序代码和数据可以同时在互联网上提供积极的网络范式，此外，他们可以在传送到目的地的过程中得到执行和修改。

ABone作为一个全球性的骨干网络，开始进行活跃网络实验。

除执行平台的不成熟，商业上活跃网络在互联网上的部署也成为主要障碍。

例如，一个供应商可能不乐意让网络路由器运行一些可能影响其预期路由性能的未知程序，。

毕业设计外文文献翻译专业学生姓名班级学号指导教师优集学院外文资料名称：Knowledge-Based Engineeri--ng Design Methodology外文资料出处：Int.J.Engng Ed.Vol.16.No.1附件： 1.外文资料翻译译文2.外文原文基于知识工程(KBE)设计方法D. E. CALKINS1.背景复杂系统的发展需要很多工程和管理方面的知识、决策，它要满足很多竞争性的要求。

设计被认为是决定产品最终形态、成本、可靠性、市场接受程度的首要因素。

高级别的工程设计和分析过程(概念设计阶段)特别重要，因为大多数的生命周期成本和整体系统的质量都在这个阶段。

产品成本的压缩最可能发生在产品设计的最初阶段。

整个生命周期阶段大约百分之七十的成本花费在概念设计阶段结束时，缩短设计周期的关键是缩短概念设计阶段，这样同时也减少了工程的重新设计工作量。

工程权衡过程中采用良好的估计和非正式的启发进行概念设计。

传统CAD工具对概念设计阶段的支持非常有限。

有必要，进行涉及多个学科的交流合作来快速进行设计分析(包括性能，成本，可靠性等)。

最后，必须能够管理大量的特定领域的知识。

解决方案是在概念设计阶段包含进更过资源，通过消除重新设计来缩短整个产品的时间。

所有这些因素都主张采取综合设计工具和环境，以在早期的综合设计阶段提供帮助。

这种集成设计工具能够使由不同学科的工程师、设计者在面对复杂的需求和约束时能够对设计意图达成共识。

那个设计工具可以让设计团队研究在更高级别上的更多配置细节。

问题就是架构一个设计工具，以满足所有这些要求。

2.虚拟(数字)原型模型现在需要是一种代表产品设计为得到一将允许一产品的早发展和评价的真实事实上原型的过程的方式。

虚拟样机将取代传统的物理样机，并允许设计工程师，研究“假设”的情况，同时反复更新他们的设计。

真正的虚拟原型，不仅代表形状和形式，即几何形状，它也代表如重量，材料，性能和制造工艺的非几何属性。

华南理工大学广州学院本科生毕业设计(论文）翻译英文原文名Review of Vibration Analysis Methods for Gearbox Diagnostics and Prognostics中文译名对变速箱振动分析的诊断和预测方法综述学院汽车工程学院专业班级车辆工程七班学生姓名刘嘉先学生学号201130085184指导教师李利平填写日期2015年3月15日英文原文版出处：Proceedings of the 54th Meeting of the Society for Machinery Failure Prevention Technology, Virginia Beach，V A, May 1-4，2000，p. 623-634译文成绩：指导教师(导师组长）签名：译文：简介特征提取技术在文献中有描述;然而，大多数人似乎掩盖所需的特定的预处理功能。

一些文件没有提供足够的细节重现他们的结果，并没有一个全面的比较传统的功能过渡齿轮箱数据。

常用术语,如“残差信号”,是指在不同的文件不同的技术.试图定义了状态维修社区中的常用术语和建立所需的特定的预处理加工特性。

本文的重点是对所使用的齿轮故障检测功能。

功能分为五个不同的组基于预处理的需要。

论文的第一部分将提供预处理流程的概述和其中每个特性计算的处理方案。

在下一节中，为特征提取技术描述，将更详细地讨论每一个功能。

最后一节将简要概述的宾夕法尼亚州立大学陆军研究实验室的CBM工具箱用于齿轮故障诊断。

特征提取概述许多类型的缺陷或损伤会增加机械振动水平。

这些振动水平，然后由加速度转换为电信号进行数据测量。

原则上,关于受监视的计算机的健康的信息被包含在这个振动签名。

因此，新的或当前振动签名可以与以前的签名进行比较,以确定该元件是否正常行为或显示故障的迹象。

在实践中，这种比较是不能奏效的。

由于大的变型中,签名的直接比较是困难的。

相反,一个涉及从所述振动署名数据特征提取更多有用的技术也可以使用。

Electro-optical target system for position and speed measurementAbstractThis paper introduces an electro-optical target system(EOTS) covering the speed range from subsonic to supersonic. This microcomputer-based system has a novel structure and shows the capability of precisely detecting the position as well as the velocity of small caliber projectiles in real time. A prototype EOTS whose target area is 1m2 has been constructed and tested. A speed accuracy of better than 0.3% was achieved. A position accuracy, mainly dependent on the spacing between photodiodes in EOTS, of better than 1mm on a target area of 1m2was also accomplished.Keywords: External ballistics, No contact measurement, Electro-optical techniques, Position measurement, Speed measurement1 IntroductionThe speed and position measurements of projectiles are two important items in ballistic research. To determine these parameters precisely one needs an accurate measuring system. A conventional method, namely the hanging up(and taking down) of target discs[l], though accurate in position measuring, is time consuming. A shot-position indicator(SPI), described in Reference 2, can measure the position of a high speed projectile by acoustic measurement. However, the SPI does not provide the speed information; neither does the conventional method. Besides, the SPI is used within the limits of supersonic projectiles.To measure the speed and position of projectiles rapidly and simultaneously, different electro-optical based systems have been proposed 3-5]. These systems have the ability to cover the speed range from subsonic to supersonic. One system, called the target measurement system(TMS)[3], uses vertical and horizontal banks of light sources to form two perpendicular light grids that construct the target area. Another system, called the electro-optical projectile analyzer[4], uses the same principle as TMS, but simplifies light sources with fiber optics bundles and a single light source in each light grid. The other system, called the electronic yaw screen(EYS)[5], uses a solid state laser that is collimated and directed to a one-dimensional beam expander system to form a fan-shaped light screen. This light screen then is reflected by a mirror to construct a portion of the target area. The light screen is more precise than the light grid because there is no dead zone in the target area as with the light grid system.From the aspect of speed and position measurement, we take advantage of the above systems and propose a novel system; the electro-optical target system(EOTS)[6]. We use a cylindrical mirror that reflects the incident laser beam into a 90º fan-shaped light screen. Two such light screens construct a two-dimensional positioning system. We even propose a bent cylindrical mirror to generate a 90º light screen with a few degrees extended in a direction normal to the light screen to reduce the sensitivity to vibrations.A prototype EOTS, whose target area is 1m2 and measured speed range is from 50m/s to 1200m/s, has been constructed and tested. A speed range of up to 5000m/s can also be expected according to the simulation results from the electronic circuit using PSpice[7]. Finally, a nine-point testing result from a 0.38in. pistol is shown in this paper. The result shows that the standard deviation of position accuracy is less than 1mm.2 Basic principle of EOTSFig. 1 shows the optical configuration of EOTS. A laser beam from a He-Ne laser is directed onto a cylindrical mirror. The reflected laser beams create a fan-shaped light screen and are directed onto photodiodes that are neatly arranged into an L-shaped photodiode array. EOTS uses two laser sources, two cylindrical mirrors and two photodiode arrays, which are arranged on the opposite sides of the EOTS body to form two fan-shaped light screens. Each light screen is combined with its own signal processing circuit to construct an optical gate. Although there is a distance between the two parallel light screens, viewed from a distance point, these fan beams intersect in a region of space called the target area (Fig. 2). A projectile can be measured only if it travels through this target area.Fig. 1 Optical configuration of EOTSFig. 3 shows the shot position of the projectile is calculated. The target area, for the convenience of illustration, is a square of dimension D on each side. The number of photodiodes on the L-shaped photodiode array is 2N . Each photodiode is numbered in order, as shown in the figure. For illustration clarity, only the photodiode array and the cylindrical mirror of the first optical gate are shown. The projectile is considered to be incident normally to the first and to the second optical gate in sequence. When the projectile blocks the light screens, the respective photodiodes will be activated by the disturbance. In the first optical gate, the laser beam from the cylindrical mirror to each photodiode makes a unique angle with the y-axis. This angle is measured counter-clockwise from the axis. The angle with respect to a photodiode, numbered n, can be calculated as 12()()arctan ,1n n n N Nδ1-=≤≤ (1) and12()arctan ,12(2)N n N n N N n δ1=+≤≤-+ (2) If certain photodiodes, numbered from j to k , are activated by projectiles, then the shot-position angle δ1, is given by()()2j k δδδ111+= (3)Fig. 2 Intersections of the two light screens in the target area Similarly, the shot-position angle of the second optical gate δ2, measured clockwise from the minus y-axis, is decided. After the two angles have been measured, theFig. 3 Illustration of shot-position calculation shot position of the projectile is deduced in Cartesian coordinates as212tan tan tan D y δδδ=+ (4) and1tan z y δ= (5)If S is the distance between the two light screens, then the average speed v for the projectile passing through the distance S is given byS v T= (6) where T is the time interval for the projectile to pass through distance S .3 Configuration of EOTS3.1 Optical system of EOTSWe use a He-Ne laser directed onto a cylindrical mirror to create a light screen. The relation among the laser beam diameter d, the cylindrical mirror diameter w and the beam expanding angle φ is shown in Fig. 4. This relation can be calculated as2arcsind w φ=2 (7) To create a light screen of which φ equals 90º, the ratio of w to d is 2.8. Because the He-Ne laser beam has Gaussian distribution and each photodiode on the photodiode array has a different distance to the cylindrical mirror, the received laser power at each photodiode is not constant. This will influence the speed accuracy of EOTS (see Fig. 6 and Section 4.1).3.2 Analogue circuitryEOTS has 2N analogue channels in each of its two optical gates. Every analogue channel has the same structure. Each analogue channel contains a photodiode, a linear amplifier, a band-pass filter and a comparator. The linear amplifier amplifies the signal coming from the photodiode. The band-pass filter filters noises such asFig.4 Laser beam directs on a cylindrical mirrorbugs flying through the light screen and flicker of other light sources nearby. The comparator compares the output V0 , coming from the filter with a threshold voltage V TH. If V0is higher than V TH, then the comparator will activate a flip-flop (FF) to change the state.3.3 Digital circuitryFig.5 is the block diagram of the digital signal processing circuit. Input coming from the analogue channel is fed to a relative FF. When the projectile blocks the light screen of the first optical gate, the state-changed FF s will make the output of the NAND gate U1 change state. The U1 locks all FF s of the first optical gate to protect genuine projectile data from the influence of shock waves behind the projectile, and starts the counter U5 that operates at a clock frequency of 10MHz. As the projectile blocks the light screen of the second optical gate, the circuit of the second optical gate functions as the circuit of the first optical gate did, but stops the counter. Moreover, the NAND gate U2 passes an interrupt signal (INT) to the central processing unit (CPU) while U5 is being stopped. The CPU then recognizes the interrupt request, picks the projectile data up, and resets U5 and all FF s for the next shot, in sequence. In Fig. 5, the counter relates the time interval T in eqn. 6. Besides, every photodiode is assigned a specific FF and every FF is given a relative address. Therefore, the CPU will be able to identify which photodiode generates the signal, to decide the impact position of eqns. 1-5, and to calculate the speed of the projectile.Fig. 5 Block diagram of digital signal processing circuit 4 Accuracy of EOTS4.1 Accuracy of speed measurementThe accuracy of projectile velocity measurement with sky-screens has been deduced by Hartwig [8] asS v T v v S∆+∆∆≤ (8) where parameters were the same as eqn. 6 used. Δv , ΔS and ΔT are values of maximum error in v , S and T , respectively. In EOTS, photodiodes are directed by nonuniform optical power, as described in Section 3.1, which implies that different analogue channels will have different response times, as though they are activated in the same way. Fig. 6 describes the typical input and output waveforms of an analogue channel when a projectile passes through the light screen. The dotted line is theFig. 6 Typical input and output waveform of analogue channelresponse of the weaker optical input with respect to the solid line. In this Figure, the optical power density directed onto the photodiode is considered to be constant along the x-axis. Referring to the solid line, the projectile touches the light screen at T1and entirely blocks laser beams at T2; the activated photodiode current I D drops from I DH to I DL.The output voltage V0of the analogue channel then rises to a saturation voltage V sat. The counter is not triggered until V0is larger than V TH. The interval from T1 to the time that V0equals V TH is called the response time t r From Fig. 6, we can realise that a different input power variation with time will produce a different output response time t r. Therefore, the ΔT of eqn. 8 should include Δt r, for EOTS, where Δt r, is the worst-case difference, i.e., the largest t r of the first optical gate minus the smallest t r of the second optical gate. Table 1 lists the simulation results of Δt r of the analogue circuit with respect to different projectile velocities using PSpice.Table 1 Simulation results of Δt, respect to projectile speed4.2 Accuracy of position measurementConsidering an EOTS structure in Fig. 3, if a photodiode, numbered n, is activated by a projectile, the exact shot-position angle δe , will be within the range1arctan()arctan(),1e n n n N N Nδ-≤≤≤≤ (9) orarctan()arctan(),12212e N N N n N N n N nδ≤≤+≤≤-+- (10) Referring to eqns. 1 and 2, eqns. 9 and 10 express that the worst-case deviation of δe , Δδ is caused by half-photodiode-spacing shift of measuring ambiguity. Thus, the deviations of the y-axis and z-axis can be deduced as1212y y y δδδδ∂∂∆=∆+∆∂∂ (11) and1212z z z δδδδ∂∂∆=∆+∆∂∂ (12) Where Δδ1 and Δδ2 are Δδ of the first and the second optical gate, respectively.2122112sec tan (tan tan )D y δδδδδ∂=-∂+ (13) 2122212tan sec (tan tan )D y δδδδδ∂=∂+ (14) 22122112sec tan (tan tan )D z δδδδδ∂=∂+ (15) and22122212tan sec (tan tan )D z δδδδδ∂=∂+ (16) It is obvious from eqns 9-16 that N has to be increased as the position accuracy needs to be better for a same size of D.Fig. 2 shows the intersection of the two light screens in the target area where intervals between photodiodes are considered to be constant. As indicated in this Figure, different detector positions will produce different resolutions. Fig. 7 shows simulation results of the worst-case deviations on the y-axis (or z-axis). The shot-position angle δ1, is fixed at 45º and the activated photodiode of the second optical gate varies from number 40 to 360 on an EOTSwith D = 1000mm and 2N = 400. Fig. 7 shows deviations on the y-axis (or z-axis) of less than 1mm corresponding to certain photodiodes that are numbered approximately from 120 to 280.A pentagon-shaped region, which is shown in Fig. 2 and has an accuracy better than 1mm, also corresponds to those photodiodes.Fig. 7 The worst-case deviation on y-axis and z-axis as δ1 is fixed at 45º5 Experimental resultsA prototype EOTS was used in the experiments. The main specifications of the system are listed as follows: d = 0.81mm, w = 2.5mm, S = 635mm, D = 1000mm, 2N = 384 and laser output optical power P = 7.5mW. We hung up a paper target behind EOTS for comparison. Fig. 8 shows the y and z coordinates of nine impact points from a 0.38in. pistol. The impact positions and the velocities were measured by EOTS. In Fig. 8, the two crosses at the bottom indicate the positions of cylindrical mirrors. Table 2 compares the results generated by EOTS with the measurement results from the paper target. The standard deviation is less than 1mm.6 Discussion and conclusionsThis paper presents a novel electro-optical target system for small calibre projectiles. Position and speed data can be generated instantaneously by the microcomputer-based control unit with the addition of appropriate software. The most accurate region of positioning, which is a pentagon-shaped area, distributes over the centre of the target area. The accuracy of position and speed measurement has been analyzed in this paper. To improve the speed accuracy, we should reduce the influence of the response time difference. To increase the distance between the two light screens, of course, is another method to improve the speed accuracy, but the position accuracy will become worse. To improve position accuracy, the photodiode array which has less space between two adjacent photodiodes is suggested.Fig. 8 The computer printout of EOTS, origin is shifted to centre of the target area The measured speed range of EOTS is from subsonic to supersonic. A speed accuracy of better than 0.3% is accomplished. With a different design concept, EOTS need not synchronized with the firing signal as EYS. It is always ready for any advancing projectile as the power of EOTS has been turned on.Fig. 9 Laser beam directs on a bent cylindrical mirrorIf a slightly bent cylindrical mirror were used (Fig. 9), the light screen could extend a few degrees in the x-direction. This makes optics alignment easier and insensitive to vibrations. However, the surface quality of the cylindrical mirror is critical to the uniformity of the fan-shaped beam in the x-direction. The nonuniformity of the fan beam in the x-direction will enhance the sensitivity to vibrations.Table 2 List of results measured by EOTS and by artificialComparing EOTS with EYS and other conventional methods, EOTS has the following advantages:(a) It can measure position and speed precisely and simultaneously.(b) Its optical system is simple and easy to set up.(c) It is insensitive to vibrations if a bent cylindrical mirror is used.(d) Its speed range covers subsonic to supersonic.References[1] BETTERMANN, P, and MAYER, F. Handbook on weaponry. Rheinmetall GmbH, Dusseldorf, 1982.[2] FARRAR, C.L., and LEEMING, D.W. Military ballistics. Brassey’s Publishers Limited, 1983.[3] CRITTENDEN, E.C., KING, R.A., and ANDREWS, T.C. Target measurement system for precise projectile location. US Paten No.3727069, 1973.[4] BAILEY, T.B., and BATES, J. Electro-optical projectile analyzer. US PatentNo.4272189, 1981.[5] DECK, L.L. An optical device for rapid measurement of the speed, dispersion, attack angle and shock wave of high velocity small caliber projectiles. Proceeding of 10th International Symposium on Ballistics, 1987, 1,pp. 1-9.[6] LU, S.T., YU, A.T, and CHOU, C. Electro-optics target for position and speed measurement, Proc. SPIE, 1988, 981, pp.250-254[7] TUINENGA, P.W. SPICE a guide to circuit simulation and analysis using PSpice. Prentice-Hall, 1988.[8] HARTWIG, R. Accuracy of velocity measurement of projectiles with fins and tracers by means of sky-screens. J. Ballistics, 1986, 9, (3), pp.2299-2310.光电目标位置和速度测量系统摘要本文介绍了一种光电目标系统(EOTS)，其速度测量范围从亚音速到超音速。

编号：桂林电子科技大学信息科技学院毕业设计(论文)外文翻译（原文）系（部）：专业：学生姓名：学号：指导教师单位：姓名：职称：年月日1、所填写内容“居中”对齐，注意每项下划线长度一致，所填字体为三号字、宋体字。

2、A4纸打印；页边距要求如下：页边距上下各为2.5 厘米，左右边距各为2.5厘米。

正文：要求为小四号Times New Roman字体，行间距取固定值（设置值为20磅）；字符间距为默认值（缩放100%，间距：标准）。

页眉处“共X页”，X需要手动修改。

大功率LED散热的研究摘要：如何提高大功率LED的散热能力，是LED器件封装和器件应用设计要解决的核心问题。

介绍并分析了国内外大功率LED散热封装技术的研究现状，总结了其发展趋势与前景用途。

关键词：大功率LED；散热；封装1. 引言发光二极管（LED ）诞生至今，已经实现了全彩化和高亮度化，并在蓝光LED 和紫光LED 的基础上开发了白光LED ，它为人类照明史又带来了一次飞跃。

发光二极管（LED）具有低耗能、省电、寿命长、耐用等优点，因而被各方看好将取代传统照明成为未来照明光源。

而大功率LED 作为第四代电光源，赋有“绿色照明光源”之称，具有体积小、安全低电压、寿命长、电光转换效率高、响应速度快、节能、环保等优良特性，必将取代传统的白炽灯、卤钨灯和荧光灯而成为21世纪的新一代光源。

普通LED 功率一般为0.05W ，工作电流为20mA ，大功率LED可以达到1W，2W，甚至数十瓦！工作电流可以是几十毫安到几百毫安不等。

其特点具有体积小、耗电小、发热小、寿命长、响应速度快、安全低电压、耐候性好、方向性好等优点。

外罩可用PC管制作，耐高温达135 度，低温-45 度。

广泛应用在油田、石化、铁路、矿山、部队等特殊行业、舞台装饰、城市景观照明、显示屏以及体育场馆等，特种工作灯具中的具有广泛的应用前景。

但由于目前大功率白光LED 的转换效率还较低，光通量较小，成本较高等方面因素的制约，因此大功率白光LED 短期内的应用主要是一些特殊领域的特种工作灯具，中长期目标才能是通用照明领域。

XXXX大学本科毕业设计(论文)外文翻译原文：How Visual Studio .NET Generates SQL Statements forConcurrency ControlAuthor: Steve SteinVisual Studio TeamAbstract: This paper examines the SQL statements Visual Studio® .NET generates for different kinds of concurrency control, how to modify them for better performance, and how to generate a statement that does not use concurrency control. (5 printed pages).IntroductionAny application that might have multiple users simultaneously attempting to access and modify data needs some form of concurrency control. Otherwise, one user's changes could inadvertently overwrite modifications from other users. The design tools in Visual Studio .NET can create SQL statements that use the "check all values" approach to optimistic concurrency or the "last-in wins" approach to updating data. This paper will explain:∙How each of these statement types are generated.∙How to modify the generated SQL statement for better performance.PrerequisitesYou should have an understanding of:∙Fundamental data concepts, including datasets and data adapters. For more information, see Introduction to Data Access with .∙Concurrency control basics and the options available in Visual Studio .NET. For more information, see Introduction to Data Concurrency in .Where Are the SQL Statements?SQL statements are located in the CommandText property of command objects. SQL commands are automatically generated at design time when configuring data adapters, and at run time when using command builder objects. For more information, see Concurrency and Command BuilderObjets .before us have addressed overlay network programming issues. Even early overlay network Configuring Data Adapters∙Drag a data adapter from the Data tab of the Toolbox∙Drag a table from Server Explorer∙Modifying an existing adapter, by selecting a data adapter and clicking the Configure Data Adapter link at the bottom of the Properties window.Command Builder objects∙Command builder objects are created programmatically at run time. For more information, see (SqlCommandBuilder or OleDbCommandBuilder)Concurrency and Data AdaptersWhen configuring data adapters with the Data Adapter Configuration Wizard, you can decide whether to use optimistic concurrency for the generated Update and Delete statements.Considerations and Caveats∙Your data source must have a primary key in order for the SQL statements to be generated to use optimistic concurrency.∙When creating data adapters by dragging tables from Server Explorer, the data adapter creates Update and Delete statements that are automatically configured for optimisticconcurrency. If you do not want to use optimistic concurrency, you can reconfigure the dataadapter: Right-click the adapter and select Configure Data Adapter from the shortcut menu,then clear the Use optimistic concurrency option of the Advanced SQL Generation OptionsDialog Box. The wizard will recreate the statements without the additional code to check forconcurrency violations.∙When reconfiguring an existing data adapter, note that the advanced settings all revert to their default state. For example, if you cleared the Use optimistic concurrency option when theadapter was originally configured, it will automatically be selected if you reconfigure it, even if you do not access the Advanced SQL Generation Options dialog box.∙If you select the Use existing stored procedures option in the Choose a Query Type section of the Data Adapter Configuration Wizard, the option to use optimistic concurrency is notavailable. The stored procedures will execute as is, and any desired concurrency checkingmust be done within the stored procedure, or programmatically built into your application.。

Anti-Aircraft Fire Control and the Development of IntegratedSystems at SperryT he dawn of the electrical age brought new types of control systems. Able to transmit data between distributed components and effect action at a distance, these systems employed feedback devices as well as human beings to close control loops at every level. By the time theories of feedback and stability began to become practical for engineers in the 1930s a tradition of remote and automatic control engineering had developed that built distributed control systems with centralized information processors. These two strands of technology, control theory and control systems, came together to produce the large-scale integrated systems typical of World War II and after.Elmer Ambrose Sperry (I860-1930) and the company he founded, the Sperry Gyroscope Company, led the engineering of control systems between 1910 and 1940. Sperry and his engineers built distributed data transmission systems that laid the foundations of today‟s command and control systems. Sperry‟s fire control systems included more than governors or stabilizers; they consisted of distributed sensors, data transmitters, central processors, and outputs that drove machinery. This article tells the story of Sperry‟s involvement in anti-aircraft fire control between the world wars and shows how an industrial firm conceived of control systems before the common use of control theory. In the 1930s the task of fire control became progressively more automated, as Sperry engineers gradually replaced human operators with automatic devices. Feedback, human interface, and system integration posed challenging problems for fire control engineers during this period. By the end of the decade these problems would become critical as the country struggled to build up its technology to meet the demands of an impending war.Anti-Aircraft Artillery Fire ControlBefore World War I, developments in ship design, guns, and armor drove the need for improved fire control on Navy ships. By 1920, similar forces were at work in the air: wartime experiences and postwar developments in aerial bombing created the need for sophisticated fire control for anti-aircraft artillery. Shooting an airplane out of the sky is essentially a problem of “leading” the target. As aircraft developed rapidly in the twenties, their increased speed and altitude rapidly pushed the task of computing the lead out of the range of human reaction and calculation. Fire control equipment for anti-aircraft guns was a means of technologically aiding human operators to accomplish a task beyond their natural capabilities.During the first world war, anti-aircraft fire control had undergone some preliminary development. Elmer Sperry, as chairman of the Aviation Committee of the Naval Consulting Board, developed two instruments for this problem: a goniometer,a range-finder, and a pretelemeter, a fire director or calculator. Neither, however, was widely used in the field.When the war ended in I918 the Army undertook virtually no new development in anti-aircraft fire control for five to seven years. In the mid-1920s however, the Army began to develop individual components for anti-aircraft equipment including stereoscopic height-finders, searchlights, and sound location equipment. The Sperry Company was involved in the latter two efforts. About this time Maj. Thomas Wilson, at the Frankford Arsenal in Philadelphia, began developing a central computer for firecontrol data, loosely based on the system of “director firing” that had developed in naval gunn ery. Wilson‟s device resembled earlier fire control calculators, accepting data as input from sensing components, performing calculations to predict the future location of the target, and producing direction information to the guns.Integration and Data TransmissionStill, the components of an anti-aircraft battery remained independent, tied together only by telephone. As Preston R. Bassett, chief engineer and later president of the Sperry Company, recalled, “no sooner, however, did the components get to the point of functioning satisfactorily within themselves, than the problem of properly transmitting the information from one to the other came to be of prime importance.”Tactical and terrain considerations often required that different fire control elements be separated by up to several hundred feet. Observers telephoned their data to an officer, who manually entered it into the central computer, read off the results, and telephoned them to the gun installations. This communication system introduced both a time delay and the opportunity for error. The components needed tighter integration, and such a system required automatic data communications.In the 1920s the Sperry Gyroscope Company led the field in data communications. Its experience came from Elmer Spe rry‟s most successful invention, a true-north seeking gyro for ships. A significant feature of the Sperry Gyrocompass was its ability to transmit heading data from a single central gyro to repeaters located at a number of locations around the ship. The repeaters, essentially follow-up servos, connected to another follow-up, which tracked the motion of the gyro without interference. These data transmitters had attracted the interest of the Navy, which needed a stable heading reference and a system of data communication for its own fire control problems. In 1916, Sperry built a fire control system for the Navy which, although it placed minimal emphasis on automatic computing, was a sophisticated distributed data system. By 1920 Sperry had installed these systems on a number of US. battleships.Because of the Sperry Company‟s experience with fire control in the Navy, as well as Elmer Sperry‟s earlier work with the goniometer and the pretelemeter, the Army approached the company for help with data transmission for anti-aircraft fire control. To Elmer Sperry, it looked like an easy problem: the calculations resembled those in a naval application, but the physical platform, unlike a ship at sea, anchored to the ground. Sperry engineers visited Wilson at the Frankford Arsenal in 1925, and Elmer Sperry followed up with a letter expressing his interest in working on the problem. He stressed his company‟s experience with naval problems, as well as its recent developments in bombsights, “work from the other end of the pro position.” Bombsights had to incorporate numerous parameters of wind, groundspeed, airspeed, and ballistics, so an anti-aircraft gun director was in some ways a reciprocal bombsight . In fact, part of the reason anti-aircraft fire control equipment worked at all was that it assumed attacking bombers had to fly straight and level to line up their bombsights. Elmer Sperry‟s interests were warmly received, and in I925 and 1926 the Sperry Company built two data transmission systems for the Army‟s gun directors.The original director built at Frankford was designated T-1, or the “Wilson Director.” The Army had purchased a Vickers director manufactured in England, but encouraged Wilson to design one thatcould be manufactured in this country Sperry‟s two data tran smission projects were to add automatic communications between the elements of both the Wilson and the Vickers systems (Vickers would eventually incorporate the Sperry system into its product). Wilson died in 1927, and the Sperry Company took over the entire director development from the Frankford Arsenal with a contract to build and deliver a director incorporating the best features of both the Wilson and Vickers systems. From 1927 to 193.5, Sperry undertook a small but intensive development program in anti-aircraft systems. The company financed its engineering internally, selling directors in small quantities to the Army, mostly for evaluation, for only the actual cost of production [S]. Of the nearly 10 models Sperry developed during this period, it never sold more than 12 of any model; the average order was five. The Sperry Company offset some development costs by sales to foreign govemments, especially Russia, with the Army‟s approval 191.The T-6 DirectorSperry‟s modified version of Wilson‟s director was designated T-4 in development. This model incorporated corrections for air density, super-elevation, and wind. Assembled and tested at Frankford in the fall of 1928, it had problems with backlash and reliability in its predicting mechanisms. Still, the Army found the T-4 promising and after testing returned it to Sperry for modification. The company changed the design for simpler manufacture, eliminated two operators, and improved reliability. In 1930 Sperry returned with the T-6, which tested successfully. By the end of 1931, the Army had ordered 12 of the units. The T-6 was standardized by the Army as the M-2 director.Since the T-6 was the first anti-aircraft director to be put into production, as well as the first one the Army formally procured, it is instructive to examine its operation in detail. A technical memorandum dated 1930 explained the theory behind the T-6 calculations and how the equations were solved by the system. Although this publication lists no author, it probably was written by Earl W. Chafee, Sperry‟s director of fire control engineering. The director was a complex mechanical analog computer that connected four three-inch anti-aircraft guns and an altitude finder into an integratedsystem (see Fig. 1). Just as with Sperry‟s naval fire control system, the primary means of connection were “data transmitters,” similar to those that connected gyrocompasses to repeaters aboard ship.The director takes three primary inputs. Target altitude comes from a stereoscopic range finder. This device has two telescopes separated by a baseline of 12 feet; a single operator adjusts the angle between them to bring the two images into coincidence. Slant range, or the raw target distance, is then corrected to derive its altitude component. Two additional operators, each with a separate telescope, track the target, one for azimuth and one for elevation. Each sighting device has a data transmitter that measures angle or range and sends it to the computer. The computer receives these data and incorporates manual adjustments for wind velocity, wind direction, muzzle velocity, air density, and other factors. The computer calculates three variables: azimuth, elevation, and a setting for the fuze. The latter, manually set before loading, determines the time after firing at which the shell will explode. Shells are not intended to hit the target plane directly but rather to explode near it, scattering fragments to destroy it.The director performs two major calculations. First, pvediction models the motion of the target and extrapolates its position to some time in the future. Prediction corresponds to “leading” the target. Second, the ballistic calculation figures how to make the shell arrive at the desired point in space at the future time and explode, solving for the azimuth and elevation of the gun and the setting on the fuze. This calculation corresponds to the traditional artillery man‟s task of looking up data in a precalculated “firing table” and setting gun parameters accordingly. Ballistic calculation is simpler than prediction, so we will examine it first.The T-6 director solves the ballistic problem by directly mechanizing the traditional method, employing a “mechanical firing table.” Traditional firing tables printed on paper show solutions for a given angular height of the target, for a given horizontal range, and a number of other variables. The T-6 replaces the firing table with a Sperry ballistic cam.” A three-dimensionally machined cone shaped device, the ballistic cam or “pin follower” solves a pre-determined function. Two independent variables are input by the angular rotation of the cam and the longitudinal position of a pin that rests on top of the cam. As the pin moves up and down the length of the cam, and as the cam rotates, the height of the pin traces a function of two variables: the solution to the ballistics problem (or part of it). The T-6 director incorporates eight ballistic cams, each solving for a different component of the computation including superelevation, time of flight, wind correction, muzzle velocity. air density correction. Ballistic cams represented, in essence, the stored data of the mechanical computer. Later directors could be adapted to different guns simply by replacing the ballistic cams with a new set, machined according to different firing tables. The ballistic cams comprised a central component of Sperry‟s mechanical computing technology. The difficulty of their manufacture would prove a major limitation on the usefulness of Sperry directors.The T-6 director performed its other computational function, prediction, in an innovative way as well. Though the target came into the system in polar coordinates (azimuth, elevation, and range), targets usually flew a constant trajectory (it was assumed) in rectangular coordinates-i.e. straight andlevel. Thus, it was simpler to extrapolate to the future in rectangular coordinates than in the polar system. So the Sperry director projected the movement of the target onto a horizontal plane, derived the velocity from changes in position, added a fixed time multiplied by the velocity to determine a future position, and then converted the solution back into polar coordinates. This method became known as the “plan prediction method”because of the representation of the data on a flat “plan” as viewed from above; it was commonly used through World War II. In the plan prediction method, “the actual movement of the target is mechanically reproduced on a small scale within the Computer and the desired angles or speeds can be measured directly from the movements of these elements.”Together, the ballistic and prediction calculations form a feedback loop. Operators enter an estimated “time of flight” for the shell when they first begin tracking. The predictor uses this estimate to perform its initial calculation, which feeds into the ballistic stage. The output of the ballistics calculation then feeds back an updated time-of-flight estimate, which the predictor uses to refine the initial estimate. Thus “a cumulative cycle of correction brings the predicted future position of the target up to the point indicated by the actual future time of flight.”A square box about four feet on each side (see Fig. 2) the T-6 director was mounted on a pedestal on which it could rotate. Three crew would sit on seats and one or two would stand on a step mounted to the machine. The remainder of the crew stood on a fixed platform; they would have had to shuffle around as the unit rotated. This was probably not a problem, as the rotation angles were small. The direc tor‟s pedestal mounted on a trailer, on which data transmission cables and the range finder could be packed for transportation.We have seen that the T-6 computer took only three inputs, elevation, azimuth, and altitude (range), and yet it required nine operators. These nine did not include the operation of the range finder, which was considered a separate instrument, but only those operating the director itself. What did these nine men do?Human ServomechanismsTo the designers of the director, the operato rs functioned as “manual servomechanisms.”One specification for the machine required “minimum dependence on …human element.‟ The Sperry Company explained, “All operations must be made as mechanical and foolproof as possible; training requirements must visualize the conditions existent under rapid mobilization.” The lessons of World War I ring in this statement; even at the height of isolationism, with the country sliding into depression, design engineers understood the difficulty of raising large numbers of trained personnel in a national emergency. The designers not only thought the system should account for minimal training and high personnel turnover, they also considered the ability of operators to perform their duties under the stress of battle. Thus, nearly all the work for the crew was in a “follow-the-pointer”mode: each man concentrated on an instrument with two indicating dials, one the actual and one the desired value for a particular parameter. With a hand crank, he adjusted the parameter to match the two dials.Still, it seems curious that the T-6 director required so many men to perform this follow-the-pointer input. When the external rangefinder transmitted its data to the computer, it appeared on a dial and an operator had to follow the pointer to actually input the data into the computing mechanism. The machine did not explicitly calculate velocities. Rather, two operators (one for X and one for Y) adjusted variable-speed drives until their rate dials matched that of a constant-speed motor. When the prediction computation was complete, an operator had to feed the result into the ballistic calculation mechanism. Finally, when the entire calculation cycle was completed, another operator had to follow the pointer to transmit azimuth to the gun crew, who in turn had to match the train and elevation of the gun to the pointer indications.Human operators were the means of connecting “individual elements” into an integrated system. In one sense the men were impedance amplifiers, and hence quite similar to servomechanisms in other mechanical calculators of the time, especially Vannevar Bush‟s differential analyzer .The term “manual servomechanism”itself is an oxymoron: by the conventional definition, all servomechanisms are automatic. The very use of the term acknowledges the existence of an automatic technology that will eventually replace the manual method. With the T-6, this process was already underway. Though the director required nine operators, it had already eliminated two from the previous generation T-4. Servos replaced the operator who fed back superelevation data and the one who transmitted the fuze setting. Furthermore, in this early machine one man corresponded to one variable, and the machine‟s requirement for operators corresponded directly to the data flow of its computation. Thus the crew that operated the T-6 director was an exact reflection of the algorithm inside it.Why, then, were only two of the variables automated? This partial, almost hesitating automation indicates there was more to the human servo-motors than Sperry wanted to acknowledge. As much as the company touted “their duties are purely mechanical and little skill or judgment is required on the part of the operators,” men were still required to exercise some judgment, even if unconsciously. The data were noisy, and even an unskilled human eye could eliminate complications due to erroneous or corrupted data. The mechanisms themselves were rather delicate and erroneous input data, especially if it indicated conditions that were not physically possible, could lock up or damage the mechanisms. Theoperators performed as integrators in both senses of the term: they integrated different elements into a system.Later Sperry DirectorsWhen Elmer Sperry died in 1930, his engineers were at work on a newer generation director, the T-8. This machine was intended to be lighter and more portable than earlier models, as well as less expensive and “procurable in quantities in case of emergency.” The company still emphasized the need for unskilled men to operate the system in wartime, and their role as system integrators. The operators were “mechanical links in the apparatus, thereby making it possible to avoid mechanical complication which would be involved by the use of electrical or mechanical servo motors.” Still, army field experience with the T-6 had shown that servo-motors were a viable way to reduce the number of operators and improve reliability, so the requirements for the T-8 specified that wherever possible “electrical shall be used to reduce the number of operators to a minimum.” Thus the T-8 continued the process of automating fire control, and reduced the number of operators to four. Two men followed the target with telescopes, and only two were required for follow-the-pointer functions. The other follow-the-pointers had been replaced by follow-up servos fitted with magnetic brakes to eliminate hunting. Several experimental versions of the T-8 were built, and it was standardized by the Army as the M3 in 1934.Throughout the remain der of the …30s Sperry and the army fine-tuned the director system in the M3. Succeeding M3 models automated further, replacing the follow-the-pointers for target velocity with a velocity follow-up which employed a ball-and-disc integrator. The M4 series, standardized in 1939, was similar to the M3 but abandoned the constant altitude assumption and added an altitude predictor for gliding targets. The M7, standardized in 1941, was essentially similar to the M4 but added full power control to the guns for automatic pointing in elevation and azimuth. These later systems had eliminated errors. Automatic setters and loaders did not improve the situation because of reliability problems. At the start of World War II, the M7 was the primary anti-aircraft director available to the army.The M7 was a highly developed and integrated system, optimized for reliability and ease of operation and maintenance. As a mechanical computer, it was an elegant, if intricate, device, weighing 850 pounds and including about 11,000 parts. The design of the M7 capitalized on the strength of the Sperry Company: manufacturing of precision mechanisms, especially ballistic cams. By the time the U.S. entered the second world war, however, these capabilities were a scarce resource, especially for high volumes. Production of the M7 by Sperry and Ford Motor Company as subcontractor was a “real choke” and could not keep up with production of the 90mm guns, well into 1942. The army had also adopted an English system, known as the “Kerrison Director” or M5, which was less accurate than the M7 but easier to manufacture. Sperry redesigned the M5 for high-volume production in 1940, but passed in 1941.Conclusion: Human Beings as System IntegratorsThe Sperry directors we have examined here were transitional, experimental systems. Exactly for that reason, however, they allow us to peer inside the process of automation, to examine the displacement of human operators by servomechanisms while the process was still underway. Skilled asthe Sperry Company was at data transmission, it only gradually became comfortable with the automatic communication of data between subsystems. Sperry could brag about the low skill levels required of the operators of the machine, but in 1930 it was unwilling to remove them completely from the process. Men were the glue that held integrated systems together.As products, the Sperry Company‟s anti-aircraft gun directors were only partially successful. Still, we should judge a technological development program not only by the machines it produces but also by the knowledge it creates, and by how that knowledge contributes to future advances. Sperry‟s anti-aircraft directors of the 1930s were early examples of distributed control systems, technology that would assume critical importance in the following decades with the development of radar and digital computers. When building the more complex systems of later years, engineers at Bell Labs, MIT, and elsewhere would incorporate and build on the Sperry Company‟s experience,grappling with the engineering difficulties of feedback, control, and the augmentation of human capabilities by technological systems.在斯佩里防空炮火控和集成系统的发展电气时代的到来带来了新类型的控制系统。