基于去伪控制的倒立摆PID控制研究

本文研究了基于去伪控制的倒立摆PID控制问题。倒立摆是一个典型的多变量,非线性,强耦合,自然不稳定系统,而PID控制器为目前工业当中最广泛的控制器。本文设计了对应的去伪控制器,并利用Matlab仿真软件对其进行了仿真研究。     

倒立摆的模糊PID控制

本文在研究了倒立摆的系统构成的基础上分析得到了其动力学模型,并通过线性化处理推导出倒立摆在工作点附近的线性模型。通过对影响倒立摆稳定因素的分析,提出一种模糊PID的控制策略。该控制策略包括3个环路。通过理论分析和反复调整,本文得到了3个环路控制器的优化参数。最后,通过Matlab仿真和硬件在环实验,模糊PID控制的有效性将会得到验证。     

基于BP网络的广义预测控制的研究与应用

本文提出了一种基于BP神经网络的广义预测控制算法,利用BP神经网络求取广义预测控制的最优控制律,对广义预测控制算法进行了简化,使广义预测控制适用于快速控制系统。选用倒立摆系统作为研究的对象,将新算法应用于倒立摆的控制,取得了较好的控制效果,验证了方案的可行性。     

基于根轨迹方法的倒立摆系统控制器设计与灵敏度分析

首先结合倒立摆系统,采用根轨迹方法设计控制器,然后利用MATLAB函数绘制倒立摆控制系统的单位阶跃响应,在此基础上,进一步分析开环增益变化对特征根灵敏度的影响。     

基于根轨迹法的直线一级倒立摆控制系统设计

建立了直线一级倒立摆的数学模型,采用MATLAB分析了开环时倒立摆的不稳定性,运用根轨迹法设计了控制器,仿真及实控结果表明,该控制系统的设计是正确、可行的.     

温度控制器的PID数字化实现探讨

现代测温系统中广泛使用的是基于PID调节的温控器,该技术具有实现简单、可消除稳态误差等优点,但市场上大多数该类仪器都是利用模拟PID控制器实现对温度控制的,而利用计算机软件来实现PID控制算法比模拟PID控制器具有更大的灵活性和可靠性。基于此,文章在模拟PID控制器的基础上研究了数字化PID控制器的实现方法。     

基于RBF网络及GA算法的PID控制器在控制木糖醇发酵过程中ORP的应用

提出了一种结合神经网络和遗传算法的智能PID控制算法;该控制器先利用RBF辨识网络在线辨识系统模型,再利用遗传算法在线调整PID三个控制参数,将此智能PID控制器用于木糖醇发酵过程,实现了木糖醇发酵过程中ORP间接实时控制。     

直线二级倒立摆状态反馈设计

倒立摆系统是一个非线性自然不稳定系统,介绍了二级倒立摆系统的硬件组成,从运动学的角度建立了系统的数学模型,并用状态反馈对二级倒摆系统进行详细的控制设计,最后设计了系统的全维观测器,经仿真验证得到了较好的控制效果。     

基于DSP的PID控制算法的研究

随着计算机和信息技术的不断进步,数字信号处理器(DSP)技术得以飞速发展,DSP凭借其高效的实时性使得其在数据信号处理方面应用有着广泛的。PID控制算法要求控制器具有快速运算、快速响应的能力,单片机在这方面处理能力远不如DSP。本文将PID控制算法和DSP技术相结合,详细阐述了基于DSP的PID控制算法,为PID控制算法在实际工程中的应用奠定了基础。     

基于dsPIC30F6010的智能伺服控制器设计

采用经典的PID控制方法的伺服控制系统,在转动惯量变化后的控制效果不佳,必需通过重新整定控制参数,才可以达到到满意的控制效果;在建立含有转动惯量因素的控制对象模型,对伺服系统受转动惯量变化的影响进行分析;设计基于dsPIC30F6010A电机专用数字控制器的伺服系统,采用单神经元自适应PID控制算法,借助于Matlab分别对经典PID控制和单神经元自适应PID控制算法进行仿真。与经典PID控制仿真结果进行对比,可确认单神经元PID控制算法可以有效解决系统转动惯量的变化带来的控制问题,能够实现对转动惯量变化的控制对象进行有效可靠的控制。     

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.     

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。     

浅谈大体积混凝土裂缝的控制

大体积混凝土的裂缝问题是实际工程中长期困扰工程技术人员的问题,其控制技术的研究是混凝土结构研究的热点问题,具有重大的学术价值和潜伏的工程背景。     

Supply Chain Strategies in the UK Fashion Industry—The Rhetoric of Partnership and Realities of Power

This paper focuses on the fashion industry, one characterised by issues such as dramatic shifts in the scale and power of major retail buyers in the market, the advent of retailer own brands, and the nature of sourcing and supply chain decisions, issues that are increasingly global in nature. The aim of this research is to explore the nature of relationships between UK high street multiple fashion retailers and their contracted suppliers, many of whom are entrepreneurial firms by most definitions of the term. Four core themes emerge from the literature and provide a framework for the research, namely, power, process, partnership, and people. The research approach was qualitative, and conducted over a period of twelve months. The paper ends with an agenda for future research.