永磁同步电动机的自适应逆推控制

将非线性Backstepping方法用于永磁同步电机高精度伺服控制系统中,考虑了PMSM系统运行过程中诸多不确定性,以及系统输出速度跟踪问题,提出了一种新的自适应控制方法。此策略不但能够实现永磁同步电动机系统的完全解耦,而且能够有效的抑制系统参数变化对系统速度跟踪性能的影响,具有很好的鲁棒性,并且从理论上证明了闭环系统的全局渐近稳定性。     

伺服控制系统综述

针对伺服控制系统的基本构成、原理、伺服电机特性、伺服控制系统在数控机床领域的应用及伺服控制系统的发展展开论述。     

液压传动伺服系统功能的改进与完善

在液压系统中,伺服控制阀有机液伺服阀和电液伺服阀等。按伺服阀的功用,可分为流量(用于控制输出的流量)和压力(用于力或压力控制系统)伺服阀两种。     

自动控制技术应用中的天线伺服

伺服控制系统是自动控制系统的一个重要分支,伺服控制系统的控制对象各种各样,比如天线、火炮、光学瞄准装置等。我们接触最多的被控对象是天线装置,此种伺服控制系统是测控雷达、卫星通信站、炮瞄雷达等大系统的重要组成部分。所有伺服控制系统的设计与调试都是基于自动控制原理进行的。本文只对最基本的自动控制原理作一介绍,并尽可能的结合工程实践进行阐述,以期对工程设计、设备调试起到一定的参考作用。     

气动伺服系统的应用与发展

本文通过对气动伺服系统发展的介绍,主要针对典型的气动伺服测试系统做了进一步的分析,并详细介绍了气动伺服控制对位置实现精确控制的方法。     

伺服控制系统的故障检测与诊断

伺服控制系统在实际中有着广泛的应用,在理论上也受到广泛关注.本文介绍了伺服控制系统中故障检测与诊断的相关成果,分别从基于模型和基于数据两个角度阐述了各种不同的方法.     

基于单编码器反馈的多电机控制伺服驱动器的研究

随着产业升级的不断推进,机械数控化、自动化是企业提高生产效率、提升企业效益、获得持续竞争优势的重要途径之一。伺服作为驱动部件,在数控自动化领域应用广泛,作用突出。本文是基于单编码器反馈的多电机控制伺服驱动器的研究。该伺服控制系统具备多个伺服电机驱动接口,可以控制多台电机的同步运行或者各自独立运行;并且通过参数配置可选择其中一种,控制灵活,适用性好。通过位置反馈接口电路可兼容多种形式的位置反馈,克服了现有伺服控制系统中驱动器只能支持一种形式的编码器的缺点,使用方便,成本更低,便于推广。     

基于Stellaris控制器的嵌入式无线网关WEB服务器的设计探究

设计探究的主导思想是一种基于ZIGBEE技术的太阳能路灯控制器,可以实现太阳能路灯的电池板自动跟踪太阳及采用ZIGBEE技术实现路灯远程无线管控。采用伺服技术使太阳能电池板自动跟踪太阳,通过伺服技术使太阳能电池板自动跟踪太阳并采用ZIGBEE技术组建无线通讯网络实现路灯的远程管控。从而提高太阳能电池板工作效率和实现大量路灯的远程无线管控。     

SIMOTION D伺服运动控制系统在ZL26A滤棒成型机上的应用

文章根据项目研发要求,结合产品性能指标,设计以西门子SIMOTION D伺服控制系统为基础的运动控制体系,并简述伺服轴的布局与拓扑结构,着重分析设计中的重点和难点。     

浅谈液压伺服控制技术

液压伺服控制是将液压传动和伺服控制两大技术有机结合的控制技术,因此,比其它控制技术响应速度更快、控制精度更高。本文主要论述了液压传动和伺服控制的原理,进一步概括了液压伺服控制的原理和特点。     

Development in Information and Communications Technology (ICT) Statistics at the Australian Bureau of Statistics

This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field.     

Value at Risk in the Suburbs: Eminent Domain and the Geographical Politics of the US Foreclosure Crisis

Several US counties and local governments have recently considered a novel solution to the foreclosure crisis. They plan to use eminent domain to compel the owners of mortgage debt—and specifically of private‐label mortgage‐backed securities—to sell the debt to the government at a price reflecting the loan's market value. The government would then restructure the debt and resell it to new investors. The plans are striking because—in contrast to both development‐driven eminent domain and the federal subprime bank bailout—they would force investors to assume asset devaluation and increased long‐term risk. Notably, the plans have emerged as an instance of financialization‐focused politics in suburbs and suburban cities of color, specifically majority‐black and ‐Latino/a suburbs. Local support for the plans, we argue, is rooted in the long‐term disinvestment of these ‘suburbs of exception', which became targets of subprime lending and eventually sites where the ‘financial exception' has been localized. But these demographic shifts, fragmentation and fiscal pressures have at the same time created a suburban political terrain in which the plans have gained their strongest political support.     

Towards a Theory of Serendipity: A Systematic Review and Conceptualization

Serendipity – the notion of making surprising and valuable discoveries – plays a major role in the success of individuals and organizations alike. Previous research has established the importance of serendipity and identified important individual- and organizational-level antecedents. However, the literature has been dispersed and the boundaries of the concept have been blurry, leading to a lack of conceptual clarity and structure, and thus limiting validity and managerial actionability. Based on a systematic literature review, I synthesize existing management-related research on serendipity and explicate the emergence and composition of serendipity in the organizational context. I first identify three necessary conditions that differentiate serendipity from related concepts such as luck or targeted innovation: agency, surprise, and value. Then, I draw from the literature on sensemaking, event-based theorizing, and quantum-based approaches to management to conceptualize the process of cultivating serendipity in the organizational context as a process of enabling potentiality and materialization, and develop a multi-level theory of (cultivating) serendipity. This conceptualization contributes to our collective understanding of how, why, and when (i.e., under what conditions) organizations can leverage the value in the unexpected, which opens up fruitful avenues for further research.     

Accountability of NGOs in Bangladesh A critical overview

NGOs in Bangladesh have been recognized as effective change agents in the socio-economic arena throughout the world. Their contributions in micro credit, non-formal education and primary health care are widely known. NGOs play a significant role in society. NGO accountability, as a result, has become a critical issue. NGO accountability in Bangladesh has been examined here in relation to patrons, clients and themselves. Of the three relationships only accountability to patrons is in a near satisfactory state. Accountability to clients is handicapped by lack of opportunities of beneficiaries to participate meaningfully in NGO policy making. Accountability to themselves is adversely affected due to the adherence to a strictly hierarchical system and the influence of founding and charismatic NGO leaders.     

Towards an Asian model of human resource management? A comparative analysis of China,Japan and South Korea

There has been much discussion regarding the possible decline and weakening of national systems of human resource management (HRM). Yet, culture and institutions are often cited as the major stumbling blocks to this outcome. Such constraints may dissipate in the analysis, particularly if ‘regional clusters’ are considered where geographic and cultural closeness and ‘openness’ to similar economic pressures exist. In such cases, it might be postulated that convergence in HRM will occur. We argue that China, Japan and South Korea represent such a cluster. This article examines these countries, to see if a degree of convergence is taking place and if it is towards an identifiable ‘Asian’ model of HRM. A model of change is presented that distinguishes between levels of occurrence and acceptance. Details of the development and practice of HRM in each country are then set out. The article ends with a discussion and implications section and a brief conclusion.     

Ansätze und Ergebnisse anglo-amerikanischer M&A-Forschung

Based on a review of established U.S. management journals (1995–2003), six schools of thought are identified within the Anglo-American M&;A research: “Capital Market”, “Principal/Agent”, “Industrial Organization”, “Organizational Behavior”, “Human Resources” and “Strategic Management”. The literature review shows that the definition of M&;A success, the methods applied, and insights from empirical research differ according to the respective school of thought. Empirical studies focus on the resource combinations of merger partners, the specific circumstances of merger negotiations, and on integration management as antecedents of merger performance. Unfortunately, empirical findings have not yet provided reliable explanations for M&;A success. Based on the current state of Anglo-American M&;A research, the authors discuss implications for business practice, identify research gaps, and propose areas for future research.     

Introduction of New Technology with a Sound Transition of the Input-Output Structure

We examine the general equilibrium repercussions associated with the introduction of new technologies, using the generalized Leontief system that allows technological substitutions. We show that an untested introduction of cost-increasing technologies in any industry may result in creating a non-productive technological structure that does not satisfy the Hawkins-Simon condition, following the autonomous dynamic adjustment process with structural transitions in the economic system. Therefore, we propose a practicable control scheme of introducing cost-increasing technologies that strictly avoids the creation of non-productive structures in all periods of structural transition, using the available information on the ex ante technological structure.     

The Creation of the Office for National Statistics

A new Office for National Statistics was created in the United Kingdom in 1996 following a series of developments designed to strengthen the relevance and integrity of statistics. This paper describes these fundamental changes and sets out a blueprint for future progress. It also sets current developments in the United Kingdom in an historical and international context.     

What helps? Women engineers' accounts of staying on

We have considerable understanding of the obstacles that women engineers encounter and the reasons that they leave the field, but we know less about what enables them to remain. Adopting an interpretivist approach, this article examines how a group of British women engineers in two FTSE 100 companies account for “staying on” in their male‐dominated work settings. We delineate four specific forms of help that facilitate women's retention in the field. We argue that exposure to help leads to women developing a habitus that enables them to continue working in engineering. To conclude, we draw on our findings to outline HR practices that will facilitate supportive relationships in the workplace and pave the way towards developing more positive organisational climates.     

论现代物流企业的发展观

物流业经过诸多年的发展目前已经成为最热门的行业之一,物流企业的注册数量也与日俱增,达到前所未有的规模。毋庸置疑,任何企业都希望自己迅速做强做大,并成为真正现代物流企业的典型代表,要实现这一目标一个首要问题就是要解决现代物流企业的发展观问题。