Software-Based Management for Ethernet Networks

An adequate network management is an essential part for each network permitting to keep the network performance at a suitable level. In this paper, we present our work focusing on an Ethernet network which is used as background interconnection technology for a smart home system in large buildings like tenements or an office block. In this case the network is larger and especially the applications are quite heterogeneous as compared to a private smart home system. Therefore, it is hard to supply a fair and quality of service aware network meeting all the demands. This is especially challenging in the case of an Ethernet network because this technology was intended to use it as a transparent connection system without the feature to support hard quality of service. We present how this problem could be solved by a middleware which best meets the special requirement of the mentioned use case. Finally, we discuss possible design improvements of this solution and present the recent Ethernet standards that could help solve this problem in an alternative way.     

基于TTCN的测试执行方法及其应用

测试执行是协议一致性测试系统中的主要部分，本文提出一种基于测试描述语言ＴＴＣＮ的操作语义对标准测试集进行了解释执行的测试执行方法，利用这种方法所实现的一致性测试系统具有很强的灵活性和独立性，同时大大提高了测试的效率，另外，我们还介绍了基于这种测试方法所完成的协议一致性测试系统（ＰＣＴＳ）的总体结构，设计思想以及测试配置。     

The behavior of electromagnetic localized waves at a planarinterface

In this paper, we investigate the behavior of electromagnetic localized waves [LW's], which are concentrated moving pulses of energy, at an interlace between two electrically different media. We employ a previously given Fourier transform domain representation of LW's that is geometric in nature; the Fourier transform of an LW consists of a support line on a particular surface together with a weighting associated with this line. The behavior of electromagnetic LW's at an interface is somewhat involved owing to their broadband nature, but this behavior has a lucid pictorial representation in terms of the transform domain geometry and, in this paper, we exploit this representation. If an LW strikes the interface obliquely then a different LW is reflected, but the pulse transmitted into the second medium is not a LW. We give analytical and graphical evidence of this behavior. Moreover, we show that if one desires a particular LW to be propagated into the second medium, one can in some cases design the necessary non-LW pulse one needs to launch at the interface to achieve this goal     

印制电路板镀通孔制程可靠性问题与研究技术途径

影响镀通孔制程可靠性因素众多,关系复杂,需要一个有效的技术途径来研究该问题。文中总结了印制电路板镀通孔制程的各个加工步骤和工序的目的,以及制造过程中影响这些目的达成效果的影响因素。分析汇总了印制电路板镀通孔的各种失效模式和机理,及其对应的失效发生的部位和影响因素。在此基础上,明确了进行印制电路板镀通孔制程可靠性研究的技术途径,同时给出了实施这项研究的技术细节。     

Adaptive Learning Objects for t-learning

IDTV (Interactive Digital TV) opens new learning opportunities for those social groups that would hardly have access to traditional forms of education. However, viewers are not usually active learners, for this reason, education through IDTV should be offered in an attractive way, so as they get engaged in the learning experience. For this to be possible, we need to introduce personalization in the t-learning field. To achieve this goal, we present, in this paper, a proposal of self-adaptive t-learning objects, which show a different behavior depending on user's characteristics. These objects are conformant to the ADL SCORM (Sharable Content Object Reference Model) standard for which we propose an extension in order to permit this type of learning objects. We expose as well an authoring tool to these objects, which hides the implementation details to the content creator.     

Application de la méthode de la phase stationnaire à des réflecteurs d’ouverture carrée

This paper deals with the computation of a function defined by an integral whose integrand is a highly oscillatory function. The radiation integral in electromagnetism, for example, belongs to this class of integrals. The author use the stationary phase method to obtain an analytical expression of this integral asymptotic expansion and its remainder for which an upper bound is easy to find. The interest of the given formulation lies in the possibilities to compute the asymptotic expansion and to control the value of its remainder, for any order. Thus, an optimal accuracy can be obtained. Moreover, the author develops from this formulation an implementation of the algorithms, which, on one hand is general with respect to the expansion order and, on the other hand, is efficient because of its recursivity characteristics. In this paper, the integration domain is square and the second kind stationary points are only considered. However, the principles of a generalisation for an elliptic or polygonal integration domain and for first kind stationary points are put forward.     

Benefits of amplification in an inertial stepping motor

Inertial stepping motors (ISMs) are widely used in high precision applications, such as scanning tunnelling microscopy and/or micro manipulation. The resolution they are able to reach makes them especially suitable when long stroke and high resolution are needed simultaneously. However, the limited speed of this technology is its main drawback. To overcome this drawback, the present paper proposes to use an amplified actuator in an ISM instead of a classical direct actuator. The impact of this choice is studied here, from speed and electrical current points of view.This study determined in an analytical way the influence of the actuator stroke on the step size of an ISM via an optimised control signal. The results are then confronted to a lumped model to identify potential limitations. Finally, a test bench is built using three different piezoelectric actuators to obtain experimental feedback about the benefits of actuator amplification in ISMs.     

Epiphany — walking the thin line

Recent events beg the question: “When is an epi equipment vendor not an epi equipment vendor?” Answer: “When it is an epi wafer vendor”. We known it has been an accepted industry practice for equipment vendors to sell ‘technology packages’, i.e. not only the reactor and associated items, but also the recipes to help get you running. Often this includes growing a few epi wafers in the vendor's lab to help your device guys make some prototypes. Earlier this year, however, two disparate equipment vendors have announced an extension of this fo full ‘foundry’ status. What is going on and what does this blurring of roles mean for the industry?     

Control of the Reactive Power Supplied by a WECS Based on an Induction Generator Fed by a Matrix Converter

In this paper, a new control system to regulate the reactive power supplied by a variable-speed wind energy conversion system (WECS), based on an induction generator fed by a matrix converter (MC), is presented. The control system discussed in this paper is based on an input current observer, implemented using an estimation of the modulation matrix, and a nonlinear control loop that regulates the displacement angle at the MC input. The reactive power capability of the proposed system is also investigated. The work presented in this paper demonstrates that, for the proposed WECS, the maximum reactive power supplied to the grid is about 40% of the nominal value. Experimental results obtained from an experimental prototype are presented in this paper. The performance of the system using a wind turbine emulator and typical wind profiles is discussed in this paper.      

Mathematical analysis of the impact of timing synchronization errors on the performance of an OFDM system

This letter addresses the effect of timing synchronization errors that are introduced by an erroneous detection of the start of an orthogonal frequency-division multiplexing (OFDM) symbol. Throughout this letter, the term "timing error" would refer to this type of error. Such errors degrade the performance of an OFDM receiver by introducing intercarrier interference (ICI) and intersymbol interference (ISI). They can occur due to either an erroneous initial frame synchronization or a change in the power delay profile of the channel. In this letter, we provide a mathematical analysis of the effect of timing errors on the performance of an OFDM receiver in a frequency-selective fading environment. The analysis presented in this letter is for the case that no equalization technique has been used to mitigate the introduced ICI and ISI. We find exact formulas for the power of interference terms and the resulting average signal-to-interference ratio. We further extend the analysis to the subsample level. Our results show the nonsymmetric effect of timing errors on the performance of an OFDM system. Finally, simulation results confirm the analysis. The results of this letter can be easily extended to address the effect of such errors on DMT modems.     

A New Microwave Amplifier for Multichannel FM Signals Using a Synchronized Oscillator

Because of the excellent results of the noise-loading test on an IMPATT oscillator that is phase-locked to an external FM driving signal, a new microwave amplifier for multichannel FM signals using a synchronized oscillator is proposed. An IMPATT oscillator, injection-synchronized with an FM signal, is regarded as an amplifier and its noise characteristics for multichannel signals are evaluated with the noise-loading method as recommended by the International Radio Consultative Committee. The results show that when this oscillator satisfies the noise characteristics for 960 telephone message channels, it assures a gain of approximately 15 dB at 11 GHz, and in this sense, this oscillator can be regarded as an amplifier for multimessage channels. The degradation of SNR of this amplifier is less than 2 dB. This excellent result is obtained because of the following. In the video band, the modulation suppression of an FM driving signal in the injection-synchronized oscillator, such as the IMPATT, is very small, while the oscillator noise, which dominates the entire output characteristic, is considerably reduced by the synchronizing action of the oscillator. This amplification continues up to the high-frequency range in which this principle of operation applies.     

Solutions for Some Waveguide Discontinuities by the Method of Moments (Short Papers)

The electromagnetic boundary value problem of two waveguides coupled by an aperture or an aperture in a waveguide radiating into free space may be described by an integral equation. An analytical solution to this integral equation cannot be readily found due to the complexity of the kernel. However, extremely useful results may be obtained if the method of moments is employed to reduce the integral equation to a matrix equation which can be solved by known methods. In this short paper, series and shunt slots in a rectangular waveguide are analyzed using this technique.     

IC设计数据的语义数据模型

IC设计数据管理是研制一体化IC-CAD系统的重要内容。本文提出了一个适于CAD设计数据管理的语义数据模型及在此模型下IC设计数据的具体表示及管理。语义数据模型提供了表达设计实体及其相互依赖关系的一体化方法。基于此模型的设计数据管理软件已在Unix Sun3工作站上构成,并成功地应用于组合电路逻辑综合系统中。语义数据模型能提高CAD系统的可扩充性,并可很好地支持系统的模块化结构。     

Agent协商优化问题的快速混沌遗传算法

随着Internet的日益完善和电子商务的普及，如何快速、高效地进行Agent协商是我们必须面对和解决的一个重要问题。文章在Bazaar协商模型下，给出了一种快速混沌遗传算法，该算法首先将混沌机制引入遗传算法，并在搜索中，以具有一定保证的当前最优解为中心不断压缩优化变量的搜索区间，对算法进行加速。这样即克服了遗传算法过早收敛的缺点，又解决了引入混沌后遗传算法收敛慢的问题。仿真实验表明，它是解决Agent协商优化问题的一种快速有效算法。     

嵌入式Linux的图像采集与显示

随着网络技术的发展,利用嵌入式系统实现远程视频监控、可视电话和视频会议等应用已成为可能。为了实现这些应用,如何获得图像数据和显示图像是一个重要环节。针对这一点,介绍了基于S3C2410平台与嵌入式Linux进行图像采集与显示的通用方法,并简单说明了软件的开发流程。     

Reverberation-chamber research-then and now: a review of early workand comparison with current understanding

The heart of this paper is an English translation (from the original Italian) of an early (1976) paper. Interspersed with this translation is an original critical review (printed in normal text) of the paper. Much of the current theory, models, and analysis techniques associated with reverberation chambers can be directly traced to the original paper by Corona and Latmiral (1976). The paper also contained a number of interesting suggestions and applications that would make excellent research topics. The original paper is considered a classic, even though (prior to this publication), an English translation is difficult to locate and reference. Publication of this translation will help establish some of the origins of reverberation-chamber concepts that we now take for granted     

Teaching “Introduction to electrical and computerengineering” in context

In this paper we present an approach to teaching an introductory course in electrical and computer engineering to freshmen engineering students. The primary distinguishing characteristics of our approach include: providing information in an experiential context or “teaching-in-context”; focusing on “black-box”-based hierarchical decomposition as an approach to understanding complex systems; and using piecewise linear models for nonlinear elements as a way to develop intuition and understanding about the workings of circuits. The experiential context is provided by having students carry out a series of laboratory exercises involving an exciting real-world electronic system. To date, we have developed laboratory exercises around a programmable robot and a Global Positioning System receiver. The greatest challenges in teaching an intellectually substantive course to entering freshmen are their lack, on average, of the mathematics and physics background that is taken for granted in most electrical and computer engineering courses. In this paper we demonstrate that by appropriate choice of material and presentation methods this challenge can be overcome     

A new theoretical model for the prediction of rapid fadingvariations in an indoor environment

The fast fading characteristics in an indoor environment are studied through a new statistical model established under the assumption of a finite number of scatterers and based on the modified Student's t distribution. The use of this model in the indoor environment reflects (better than the conventional Rayleigh model) the conditions that are met inside buildings and are described well by a small number of easily identifiable parameters. An analytical expression for this so-called Polydorou Capsalis (POCA) distribution is developed assuming a finite number of scatterers, and its statistical characteristics are analyzed. Then, this distribution is used in order to describe the fast fading characteristics in an indoor environment. For this purpose, measurements in the 900-MHz-frequency band have been done in an office environment. The performance of the POCA distribution is compared to the conventional Rayleigh distribution, and it is found that the fast fading characteristics are better described by this distribution     

直接序列扩频多址通信系统中最佳线性多用户信号检测器研究

本文提出了平均误经特率最小意义下的最佳线性多用户信号检测器，并给出了救解这种最佳线性多用户信号检测器的近似方法－－训练单层感知器法，初步的研究结果表明；这种检测器的性能优于以往多种检测器。     

The IEEE Systems, Man, and Cybernetics Society: historical development, current status, and future perspectives

In the evolution of any professional organization, it is informative and desirable to take stock of what has occurred, and to use this assessment to consider and plan for the future. The IEEE Systems, Man, and Cybernetics (SMC) Society is considered to be the leading professional society in the transdisciplinary area of systems engineering, cybernetics, and human machine systems, and has an international reputation for our efforts in developing and presenting innovative research results related to this area. In this paper, we - group of five current and former SMC Society presidents - consider the past, present, and future of the IEEE SMC Society; we are also doing this to commemorate the Society's 30th anniversary. In particular, we address our auspicious beginning; our transition from an incubatee to an incubator society; the breadth of our transactions; the international character of our membership; the appropriateness of our name; the move toward an "intelligent" systems-oriented umbrella organization; the evolving array of research areas; and the challenges and opportunities we face in the future.