A computer-aided approach to teaching band structure formation

A computer-aided method for teaching energy band formation in a superlattice which enables direct comparison to energy band formation in crystals through the tight-binding method is presented. The time-independent Schroedinger equation for a heterostructure stack is solved by the transfer matrix method along with the effective mass approximation using a standard Fortran 77 computer code. The code is suitable for use on a personal computer which provides a ready laboratory in which the student can examine the effect of varying the electron wavefunction overlap between adjacent sites. In this way, the student can perform a series of computer experiments which vividly illustrate energy miniband formation in superlattices and by direct analogy energy band formation in crystals     

A practice driven approach to software engineering education

This paper describes a two year undergraduate education program in software engineering. This program is designed around the principle of exploratory learning, whereby the students are trained to build knowledge by themselves and actively search for solutions to the problems they experience. In addition to the essential aspects of software engineering: managing complexity of large, changing systems and the ability to work in teams; the program also aims to prepare the students for working in a field of rapidly changing conditions and constraints. This paper describes how these high level goals have been implemented in an actual curriculum. At the core of the program is a set of project courses which are conducted as role playing games in order to simulate the conditions in an industrial environment. Two years worth of students have graduated from the program now, and the paper summarizes the main lessons learned as well as a follow-up survey of experiences from some of the organizations who hired the students     

A student-enacted simulation approach to software engineering education

In some cases, real-world application of software engineering concepts does not effectively map with current undergraduate curriculums. Typically, a student's first "hands-on" experience working on large-scale software development projects is via an intern position or his/her first full-time position. However, prior exposure to the corporate project environment would greatly improve a student's performance in industry. In order to develop students for successful careers in software engineering, specifically for software development, they must be immersed not only in the software development lifecycle and paradigms, but also in the workings of large project teams. Currently, most undergraduate software engineering courses are taught by presenting the concepts and methodologies and assigning fragmented three-to-four person group projects. In the Department of Computer Science, Georgetown University, Washington, DC, a two-course approach to undergraduate software engineering education has been developed that incorporates the practical application of coursework in a large team setting. The first course presents a firm software design basis, while the second course demonstrates corporate-level software engineering concepts with a semester-long software development simulation where the entire class is the development team. This paper presents the experiences from offering this software engineering simulation approach.     

A new approach to overcome the overflow problem in computer-aided analysis of nonlinear resistive circuits

This paper is addressed to the so-called overflow problem commonly encountered in the computer simulation of nonlinear resistive circuits containing rapidly varying nonlinearities—such as exponentials found in the models of diodes and transistors. A novel approach which makes use of the arc-lengths of the nonlinear characteristic curves as the variables of iteration is proposed. It is proved, under rather mild conditions, that the arc-length approach not only overcomes the overflow problem, but also leads to a more rapid rate of convergence. Moreover, it is proved that for most practical diode-transistor circuits, the region of convergence associated with the arc-length approach is larger and the convergence of the Newton-Raphson algorithm is not sensitive to the initial guess. Since it is more difficult to make good initial guesses when the size of the network is large, in so far as choosing the initial guess is concerned, the advantage for using the arc-length approach over the conventional approach increases with the size of the network. Extensive numerical experiments confirm the superior convergence property of this approach even for circuits which violate the sufficient conditions invoked by the rigorous mathematical proofs. Although the approach is applicable to a much wider class of nonlinear networks, particular emphasis is focused on diode-transistor networks in this paper.     

A radar course at undergraduate level: an approach to systems engineering

This paper describes the undergraduate radar course taught at the Escola Universitaria Politecnica del Baix Llobregat (EUPBL) of the Universitat Politecnica de Catalunya (UPC), Barcelona, Spain. At present, the EUPBL offers a three-year degree in Technical Telecommunications Engineering. This paper briefly describes the EUPBL, the organization of the degree program, the structure of the radar course, the evaluation methods, and two practical exercises on a sonar demonstrator and a global positioning system kit.     

A new approach to enhance power quality for medium voltage ACdrives

A new approach to medium-voltage variable-frequency static AC motor drives offers improvements in power quality. Harmonic current injection into the power lines is below the most severe requirements of IEEE Standard 519-1992. The power factor of this new type of drive exceeds 94% at full load and is above 90% at 10% load. Motor voltage and current waveforms are improved so that torque pulsations are reduced. Peak voltage stress on motor insulation does not exceed peak input line voltage, and no zero sequence voltage is imposed. Drive efficiency exceeds 96%. This paper describes the new approach and some of the results achieved     

一种通用测试工程建模平台的设计方法

随着测试系统从单一的专用系统向多功能的通用开放系统方向发展,测试软件通用性实现方法的研究受到了广泛的关注。研究设计一套高效的、易于理解的通用测试软件系统成为自动测试领域的迫切需要,为了实现此目的,将重点提出一种测试工程建模平台(test engineering model platform,TEP)的设计方案。此方案的提出能够大大降低在产品测试信息建模时对传统测试人员编程能力的要求,它将会是维修、测试机载产品过程中的重要工具。该平台将应用于四线制电阻阻值的测量实验,并得出相关的实验数据论证TEP建模平台的可靠性和有效性。     

A more practical approach to integrate low voltage distributionsystem into the electrical engineering curriculum

This paper describes the author's new attempt to introduce a 10-hour lecture on low voltage (LV) distribution system with a 5-hour design exercise and a 5-hour project work for all electrical engineering students. It is felt that most of the electrical engineering graduates will possibly encounter more applications in the LV system rather than the traditional power system analysis. The system earthing and the associated electrical parts for the LV network can be easily implemented in a laboratory for students to test and operate. In the design exercise, the PC-based integrated tool not only guides the students in a step-by-step approach and provides a CAD tool to automate the repetitive design process, it also evaluates the student's performance in the design exercise by using error log and a demerit point system. In the guided project work, the students are exposed to a physical LV simulator identical to an industrial installation to carry out inspection, testing, turn-on supply, fault diagnosis and restoration of supply. In a survey from 600 students, 24% strongly agreed, and 52% agreed that this 10-hour design and project works are useful and challenging. Many students expressed that they are interested in their first exposure to a power engineering project     

A systematic approach to the implementation of final year projectin an electrical engineering undergraduate course

This paper describes a computerized management system for the processing of a final year project in an electrical engineering undergraduate course including a structured project allocation to students, a comprehensive assessment procedure, an automated processing of marks, and a management supporting system. An optical reader is used to scan the project selection made by all the students, and the allocation algorithm allocates as many projects as possible in meeting the students' preferences. A new attempt using a grading category index for each assessment criterion is implemented and the assessment of the student's performance is evaluated through five main components with 31 assessment criteria. The marks for each student are scanned by an optical reader and calculated by a weighted linear conversion of all the grading category indexes. The assessment system is more valid as it has many specific criteria and is more reliable as the process is consistent. The management supporting tools and experiences in handling very large groups of students especially in the maintenance of a uniform marking standard to all the students are highlighted. It is hoped that some of our approaches can be selectively adopted for undergraduate course work on continuous assessment even for a smaller student population     

Innovative methodology to improve the quality of electronic engineering formation through teaching industrial computer engineering

An innovative educational methodology adapted to the requirements of a new era with new societal and industrial challenges for electronic engineers is proposed in this paper. This active methodology, known as the Educational Innovation Project (EIP), is being studied in the Electronic Engineering (EE) degree of the Higher Technical School of Design Engineering at the Polytechnic University of Valencia, Valencia, Spain. The main objective of the EIP methodology is to improve the process of teaching and learning in order to increase student success. To accomplish this objective, the EIP method addresses various issues. From an organizational viewpoint, different structural aspects of the EE degree have been adapted, such as balancing and integrating lectures and laboratory sessions, advancing into interdisciplinary studies coordinated among all the subjects of the course, and strengthening the work in teams to tackle real engineer problems. The industrial computer engineering (ICE) subject is taken as a reference to show how these aspects have been applied. Regarding the faculty, lecturers participate in an open and permanent process of further training; attitudes toward cooperation and exchanges of experience among them are promoted; and research and reflection on new methodologies is encouraged. One of the challenges of the implementation of the EIP project is the development of multidisciplinary projects by team workers. The knowledge acquired from all the subjects is put into practice through the development of a common project to undertake real engineering problems.     

全面推进可靠性工程,提高机电产品质量

提高机电产品可靠性与用户满意度是当前质量工作的核心任务,是创名牌的重要内容,是企业扩大市场占有率的重要手段.改革开放以来,产学研各界的有识之士,积极探索和推动机电产品提高可靠性的途径,取得了不少成果,为我们的机电行业全面推广可靠性这一重要工作积累了宝贵经验.     

A new approach to identification of transient power quality problems using linear combiners

In this paper, we present a new approach to identify transient power quality disturbances using linear combiners and a fuzzy decision support system. The key idea underlying the approach is to obtain the amplitude and the slope of the peak fundamental component of a voltage waveform using adaptive linear combiners, along with nonlinear least mean squares (LMS) algorithm. Fuzzy logic is then used to identify the class to which the waveform belongs by a set of heuristic rules and an uncertainty index. Detailed digital simulation results involving various types of transient power quality disturbances are presented to prove the ability of the new approach in classifying these disturbances.     

Use of dielectrometry to control quality and choose parameters for manufacturing thermosetting materials

The process of hardening was investigated and its kinetics parameters responsible for the technological characteristics of thermosetting materials for electric machines high-voltage stator windings were determined. The necessity of tight control of the parameters of the kinetics of resin-rich tapes in order to achieve the necessary level of insulation characteristics was shown.     

A generalized,complex adjoint approach to power network sensitivities

A unified study of the class of adjoint network approaches to power system sensitivity analysis which exploits the Jacobian matrix of the load flow solution is presented. Generalized sensitivity expressions which are easily derived, compactly described and effectively used for calculating first-order changes and gradients of functions of interest are obtained. These generalized sensitivity expressions are common to all modes of formulating the power flow equations, e.g. polar and Cartesian. the approach exploits a special complex notation and complex matrix manipulations to define the adjoint system and to derive the sensitivity formulae. the approach is applicable to both real and complex function sensitivities.     

A scientific approach to math

The authors demonstrate how computers can be used for mathematical discovery; they have provided two experiments as examples. The first experiment deals with the behavior of consecutive sums of integers. The second experiment allows one to generalize a property of the eigenvalues of square matrices to matrices of arbitrary dimensions. They close by explaining how to set up an experiment designed to discover something new     

A cost-effective approach for the development of an integratedPC-PLC-robot system for industrial engineering education

Advanced manufacturing technology (AMT) instruction is and is likely to remain an important component of the industrial engineering education curriculum. As new manufacturing technologies become available and as existing manufacturing technologies become more integrated, industrial engineering departments must continuously develop their laboratory resources in order to provide their students with effective instruction. While financially limited departments cannot acquire state-of-the-art manufacturing equipment, they can provide improved hands-on AMT integration instruction without major capital investment. By developing an interface box between existing LabVolt PLC trainers and Microbot TeachMover robots, the industrial engineering department at a major Northeastern US university was able to provide its students with improved AMT integration instruction     

Recent advances in engineering science as applied to aeolian vibration: an alternative approach

This paper summarizes modern advances of nonlinear mechanics, fluid dynamics, and vortex-induced vibrations as applied to aeolian vibrations. It presents a new and simple method of calculating the aeolian response of a single conductor, which circumvents the uncertainty of the energy input due to wind.     

光伏并网发电与电能质量调节统一控制系统

结合光伏并网系统与有源电力滤波器在控制结构和控制策略上的相似性,研究了一种既能实现光伏并网发电又能实现电能质量调节的统一控制系统。对传统的光伏电池最大功率跟踪(Maximum Power Point Tracking,MPPT)方法进行了改进,给出了流程图。针对统一控制系统特点,在PI控制基础上,提出了准PIR控制策略,从理论上分析了其优势,并给出了各参数的计算方法。在Matlab环境下,搭建了系统的仿真模型,仿真结果证明了该系统结构和控制策略的有效性。     

A new approach to switching, fault protection, and overloadmonitoring of distribution transformers

The major current monitoring and control functions for distribution transformers include: switching transformers in and out of the distribution system; sensing and interrupting secondary faults; sensing and interrupting primary faults; and monitoring transformer loading with indication and isolation capability. A novel primary switch and overcurrent protector device for handling all these requirements is presented. The device's sensor element and magnet latch are described, and its testing and application are discussed. Although it is designed specifically for use in overhead, completely-self-protected transformers, it could be modified for use in pad-mounted transformers