Robust dissipative control for internet-based switching systems

A class of hybrid multi-rate control models with time-delay and switching controllers are formulated based on combined remote control and local control strategies. The problem of robust dissipative control for this discrete system is investigated. An improved Lyapunov-Krasovskii functional is constructed and the subsequent analysis provides some new sufficient conditions in the form of LMIs for both nominal and uncertain representations. Several special cases of practical interests are derived. A numerical simulation example is given to illustrate the effectiveness of the theoretical result.     

基于ARM的高频开关电源数字控制系统设计

随着新型功率器件的日趋成熟,更灵活可靠的数字控制是开关电源的发展方向。基于此,采用了先进精简指令集运算机（ARM）处理器来实现脉宽调制（PWM）移相控制信号的输出,以实现软开关电源PWM反馈回路的数字控制。实验结果表明,设计能达到预期的性能要求。     

开关图的谱

首先根据开关图的定义用原图的邻接矩阵表示其开关图的邻接矩阵,然后用原图的特征多项式表示其开关图的特征多项式．对于正则图,用正则图的谱表示其开关图的谱．     

Being a ‘Purist’ in Hong Kong: To Use or Not to Use Mixed Code

This paper reports on my first‐hand experiences of being a ‘purist’ in Hong Kong, during which time I was not allowed to use mixed code, a common discursive practice among Hongkongers in Hong Kong. I shall discuss the difficulties in using ‘pure’ English and ‘pure’ Chinese in my daily life, as well as exploring the problems I encountered when I used ‘pure’ English in teaching English to a small group of ESL students at a primary school in Hong Kong. I argue that mixed code is very much characteristic of everyday language use by most Hongkongers and represents an important marker of their ethno‐linguistic identity. In relation to language teaching, I suggest that mixed code may be usefully adopted in teaching English in Hong Kong, rather than being shunned at all costs.     

TOPSwitch-GX单片开关电源的设计

电源性能的优劣直接影响电器产品的质量,传统采用的工频变压器由于体积大、耗材多、损耗大、效率低正逐步被淘汰.针时上述的这些缺点,利用TOPSwitch-GX芯片,提出一种单片开关电源的设计.与传统的工频变压器相比,它具有更加优越的性能.     

基于转移成本和质量成本差异的软件提供商竞争博弈模型:SaaS vs. SWS

考虑了作为软件领域先行者的SWS提供商由于企业用户前期IT投资所引发的客户转移成本,以及SaaS与SWS之间日益减小的质量成本差异问题,构建了基于序贯博弈的经济模型。研究发现:转移成本对SWS提升产品质量、产品定价以及其利润水平具有正向的推动作用,而对SaaS提供商而言,这种作用是反向的;SaaS与SWS之间质量成本差异系数的减小对双方竞争策略的影响则取决于具体的转移成本环境;考虑到两因素的联合作用,随着质量成本差异系数的日趋减小,在不同的转移成本环境下,转移成本的高低对于软件提供商采取更加激进还是更加保守的投资策略至关重要。     

对校园交际中英汉语码转换现象的功能分析

语码转换指在同一次对话或交谈中,说话者使用两种或两种以上的语言变体的现象。它是语言接触的一种常见现象。大学校园中教师和学生会根据实际情况进行语码转换。尝试对大学校园交际中英汉语码转换的功能作出分析,指出英汉语码转换是对语言现实、社会规约以及心理动机的顺应。     

光分组交换节点物理性能仿真

A graphical and visual simulation system for the study of optical packet switching(OPS)nodes is accomplished.With the simulation system,the effect on physical performance-bit error rate(BER)due to a variety of factors such as the crosstalk parameters of OPS nodes,number of cascaded OPS nodes,length of optical output buffer,traffic load and fluctuation of amplitude of optical signals are evaluated.Reliability of the simulation system is proved by the analytical results obtained in all the above cases.     

基于SVPWM控制的UPFC暂态数学模型的研究

引入开关函数的概念,考虑了统一潮流控制器(UPFC)各相桥臂电力电子器件具体的开关状态以及三相电网电压的不平衡因素,建立了可反映UPFC装置内部开关特性和运行机理的UPFC暂态数学模型.该模型能够反映UPFC最终的输入控制量及输出量,并合理地设计了应用于该模型的电压空间矢量脉宽调制(SVPWM)控制方案.     

引进现网通信设备构建通信实验室

改革采用实验箱组建通信实验室的传统实践教学方法,通过引进程控交换机、SDH光传输设备及数据通信等现网通信设备,配以2G和3G移动通信仿真教学平台,组建新型的通信实验室,为学生提供真切的通信系统实验环境,增强了学生的实际动手能力,提高了学生的职业素养。