The Superiority of Row Vectors for Matrix Block Diagrams

The author points out why row vectors should be used in matrix equations for cascade systems. The use of the popular column vectors for this purpose causes considerable trouble. With row vectors, the matrices and the black boxes of the diagram are in the same order naturally, while with column vectors they can only be brought into such order by artificial means, such as inverse transfer functions and backward signal flow graphs.     

继电器电路图移植为梯形图的方法

本文介绍了将继电器电路图直接转换为PLC的梯形图,PLC的输入电路与梯形图的关系,用PLC的定时器实现时间继电器功能的方法,和在PLC外部设置硬件互锁的问题.     

Reciprocal Citizens Exchange: A Confidence-Building Alternative to Nuclear Deterrence

This paper articulates a new and very different approach to deterrence in the nuclear age, one focussed on the underlying causes rather than the more easily visible effects of superpower intransigence, one based on positive rather than negative incentives, and one with the unusual potential to remove barriers (whether perceived or real) between political adversaries rather than continuously to create them. I suggest a deterrent ``force,' or perhaps more appropriately a ``restraining presence,' that uniquely combines inhibition of war-like or destabilizing acts in the short term with the simultaneous enhancement of transnational understanding over the longer term, at all levels of the body politic. Specifically, I propose a highly visible, mutially endorsed and deliberately massive effort by both the U.S. and the U.S.S.R. in support of a confidence-building program involving the reciprocal exchange, from one nation to the other, of large numbers of citizen ``hostages' chosen from all walks of life. Over a period of a generation or more, these carefully-selected and well-prepared volunteers would have the opportunity to lay the psychological and political groundwork for a significant and powerful, yet non-violent and gradual, shift in the conceptualization of deterrence currently endorsed by both superpowers.     

UML图表到SVG图形转换方法研究

通过分析统一建模语言(UML)对象模型到可扩展标记语言(XML)文档实例的映射关系,依据扩展标记语言元数据交换标准(XMI2.0)生成了包含UML模型信息的XML文档,再应用XSLT变换将XML文档转换成可伸缩的矢量图形(SVG)格式,最终将UML图表转换为SVG图形.这种方法利用了SVG的优点,对UML图的Web发布十分有益.     

Enhanced Modulation Characteristics of Optical Injection-Locked Lasers: A Tutorial

In this paper a tutorial of optical injection locking of semiconductor lasers is given, with particular emphasis on the enhancement of system parameters. Furthermore, physical intuition of each parameter enhancement is explained and practical design rules and trends are also shown.      

Applying Audlio Tutorial Techniques to Laboratory Instruction

In the senior communication theory course at Purdue University, instructional material which was formerly handled in a lecture-type preparation session is now being presented individually to students by means of audio tape recordings. Features of the audio tutorial method of instruction are discussed, with emphasis on the advantages and flexibility the method affords in laboratory instruction. The interplay between taped material, written notes and instructor activities is also discussed. Information for those interested in obtaining a sample audio tutorial tape is given at the end of the paper.     

电力负荷预测知识体系的教学研究

电力负荷预测与电力部门的规划、计划、运行及管理等工作联系紧密,电力行业分营后,各企业实体急需大量的分析与预测人才。在电气信息类专业开设的“电力负荷预测”课程中,如何在有限的课时内,既考虑预测理论知识的要求,又考虑到电力企业的预测工作的实际需要,以及负荷预测技术的发展,在课程的内容的设计、学生能力的培养、考试方式等方面,做了一些有益的探索,以期达到宽口径电气人才培养的目的。     

配电馈线地理图到电气接线图的转换

为了将配电馈线的地理接线图转换为电气接线图,建立了基于图论的配电网模型。根据空间位置和所含节点数目对分支进行分级,将一条馈线分解成由若干分支构成的集合。在电气接线图上,遵循将偶数级分支水平放置,将奇数级分支垂直放置,并注意确保各个分支的相对走向不变的原则,按照分支级数由小到大的顺序每次添加一条分支,若产生交叉或重叠则采取水平或垂直一维局部拉伸平移法来消除,从而根据馈线的地理接线图逐步生成了电气接线图。结合实例详细说明了所提出方法的基本原理,结果表明该方法可行。     

A Tutorial Communication System? Blackboard-by-Wire Plus Picturephone Set

The combination of blackboard-by-wire plus Picturephone is analyzed as a tutorial communication system to teach engineers at their job locations. This developing system, based on use of the common-carrier telephone system, has advantages over closedcircuit (talkback) television systems. The remote blackboard can be three panels for nearly "full-wall" presentation, and two-way video may be added fairly economically. Using the common-carrier system maximizes flexibility (access to any termination in the entire switched system) and should be more cost-effective. By time-sharing the tutorial communication function with other uses, one avoids development of a separate dedicated microwave system (and associated maintenance). The current implementation of blackboard-by-wire is described and is shown to be sufficiently effective to serve as a communication system until Picturephone can be economically added. The author's experience with blackboard-by-wire is described, along with a survey of past uses. Costs are analyzed, showing that the present system requires about $5000 for equipment purchase (for one "sender" and one "receiver") and $20 to $40 per hour for transmission costs. The flexibility and low cost of the current implementation make it an easy "entry point," and it is compatible with later expansion to include Picturephone set.     

Electrical Surge-Protection Devices for Industrial Facilities—A Tutorial Review

Industrial facilities are becoming more and more dependent on computer control of their processes, and as a consequence, require an increase in cleanliness and reliability of the electrical power supply system. Electromechanical subsystems are being replaced by electronic logic. Harmonic interference, welding, variable speed drives, and other "in plant" noise have reliable mitigation procedures. However, lightning and other external sourced power disturbances rank high on the list of "uncontrollable" events that have shut down facilities in recent years. This paper provides an overview of the causes of power-line surges and their consequences for an industrial plant. The relevant international surge-protection standards will be briefly reviewed, and their differences will be analyzed. Different technologies utilized in the implementation of various commercially available surge-protection devices will be presented, followed by a comparative analysis. Finally, the latest trends and the most promising technologies in surge-protection systems as well as their ability to overcome the problems associated with conventional protection devices will be overviewed, and experimental data based on field trials are reported     

A Communication Curriculum in Engineering Education: An Alternative Model

Typical model curricula in engineering disciplines assume that training in communication will occur early in the students' academic career in the courses taken to meet the general liberal arts requirements of the university. This paper argues that this assumption defines communication as a preliminary skill to be learned as a prelude to technical study. An alternative view perceives increasing sophistication in the technical disciplines as requiring a simultaneous increase in sophistication in communication. The Program in Scientific and Technical Communication at the University of Washington is designed according to the latter view. Our courses address the needs of engineers as these needs emerge and change across the academic and professional life of the engineer.     

A New Challenge for Alternative Energy

The year 2008 sees a turning point in China’s strategy of promoting energy saving and emissions reduction, as well as development of renewable energy. Oil price breaking US$140 and large area in China suffering from     

Cast Coil Transformers: An Alternative to Conventional Dry Type Transformers

Now that askarel insulated transformers are no longer available because of environmental regulations, engineers are looking to new approaches in design of nonflammable transformers. Cast coil construction is one promising new design. Cast coil construction is compared with the more familiar conventional dry type construction with particular attention to 15 kV class units up to 5000 kVA in rating. Questions of reliability, energy efficiency, performance characteristics, maintenance requirements, and initial costs are explored in detail.     

A Tutorial Presentation of Statistical Procedures for Educational Experiments in Engineering Laboratories

This paper describes, in tutorial fashion, statistical procedures for educational experiments involving engineering laboratories. The sequence of the procedures is 1) formulation of the problem, 2) formulation of the hypotheses, 3) identification of the sample, 4) specification of the population, 5) construction of measuring items, 6) collecting data in cognitive and affective domains, 7) statistical analysis of the data, and 8) conclusions based on statistical analysis. This study was carried out at Michigan State University in an electrical engineering course (108 students). The statistical analysis was based on the outcome of four tests: pretest, posttest, retention test, and student attitude test.     

A Proposed Alternative to Locational Marginal Pricing and its Impact on New Generation

The author follows up his earlier critique of locational marginal pricing by offering an alternative approach to LMP for congestion management involving compensation payments for constrained up and constrained down generation and an allocation algorithm of those payments to constrained interfaces and ultimately to the users of the transmission system. This alternative compensation/charge method provides greater incentives for the development of new generation than does LMP.     

Nuclear Deterrence: An Alternative Model

Deterrence is often described as two armed opponents facing each other but neither attacking because of the threat of retaliation by the other. This mistake lies in an imagery that sees the opposing parties as though each were individual persons or small groups. This article views strategic conflict as emerging from large-scale systems containing many individuals performing many different roles. By examining the adaptive tendencies of these systems, an alternate perception of moral and rational deterrence is developed.     

一种实用的动平衡机（仪）电气校零电路

本文中介绍了一种实用的动平衡机（仪）检测电路中的电气校零电路。该电路通过对转速信号进行移相、５０％占空比变换、锁相倍频以及滤波等环节，可得到和相位可任意调整且与转速同频的标准正弦波信号，该正弦波可作为动平衡机校零件补偿信号。该电路能自动跟踪不同的测量转速的变化，且输出正弦波的相位能实现０℃￣３６０℃之间的线性调节。