双馈发电系统中电网侧高频整流器的研制

基于三相PWM高频整流器的数学模型,详细分析了双馈发电系统中电网侧整流器的双闭环控制原理和单位功率因数的实现方法。在此基础上设计了一套整流装置,可以单位功率因数运行在整流和逆变状态下,能够实现能量的双向流动,实验结果表明该整流装置具有良好的动、静态特性。     

Evaluation of a Computer-Assisted, 2-D Virtual Reality System for Training People With Intellectual Disabilities on How to Shop.

Objective: To evaluate the effectiveness of a 2-D virtual reality (VR) program for training people with intellectual disabilities to shop. Study Design: Pretest and posttest quasi-experimental design. Participants: Sixteen persons with intellectual disabilities (age 17-23 years; IQ = 40-54). Intervention: A VR program or a conventional program training them in supermarket-shopping skills. Main Outcome Measure: Checklist for supermarket-shopping skills. Results: Participants in both training groups showed significant improvement. There was no significant difference in effectiveness between the two methods. Conclusions: The VR program appears effective in training people with intellectual disabilities in an important community living skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Security and privacy in sensor networks

Sensor networks offer economically viable solutions for a variety of applications. For example, current implementations monitor factory instrumentation, pollution levels, freeway traffic, and the structural integrity of buildings. Other applications include climate sensing and control in office buildings and home environmental sensing systems for temperature, light, moisture, and motion. Sensor networks are key to the creation of smart spaces, which embed information technology in everyday home and work environments. The miniature wireless sensor nodes, or motes, developed from low-cost off-the-shelf components at the University of California, Berkeley, as part of its smart dust projects, establish a self-organizing sensor network when dispersed into an environment. The privacy and security issues posed by sensor networks represent a rich field of research problems. Improving network hardware and software may address many of the issues, but others will require new supporting technologies.     

主变压器瓦斯保护误动分析

对一起主变压器瓦斯保护误动作进行分析,用精确的数据证明,瓦斯继电器由于雨水原因造成瓦斯保护只发信号但保护却不出口的情况存在.     

Symbolic connectionism in natural language disambiguation

Natural language understanding involves the simultaneous consideration of a large number of different sources of information. Traditional methods employed in language analysis have focused on developing powerful formalisms to represent syntactic or semantic structures along with rules for transforming language into these formalisms. However, they make use of only small subsets of knowledge. This article describes how to use the whole range of information through a neurosymbolic architecture which is a hybridization of a symbolic network and subsymbol vectors generated from a connectionist network. Besides initializing the symbolic network with prior knowledge, the subsymbol vectors are used to enhance the system's capability in disambiguation and provide flexibility in sentence understanding. The model captures a diversity of information including word associations, syntactic restrictions, case-role expectations, semantic rules and context. It attains highly interactive processing by representing knowledge in an associative network on which actual semantic inferences are performed. An integrated use of previously analyzed sentences in understanding is another important feature of our model. The model dynamically selects one hypothesis among multiple hypotheses. This notion is supported by three simulations which show the degree of disambiguation relies both on the amount of linguistic rules and the semantic-associative information available to support the inference processes in natural language understanding. Unlike many similar systems, our hybrid system is more sophisticated in tackling language disambiguation problems by using linguistic clues from disparate sources as well as modeling context effects into the sentence analysis. It is potentially more powerful than any systems relying on one processing paradigm     

5G14433和MCS-51单片机接口电路的调试过程

通过5G14433芯片与MCS-51单片机接口电路的实例,说明了硬件电路的调试过程.     

形状记忆合金电机在机器人中的应用研究

作为新型功能材料的形状记忆合金(SMA)在工程机械和日常生活中得到了广泛的应用。由SMA构成的结构简单、控制灵活、功率密度大的电机(SMAA)，在机器人系统中具有独特的技术优势。文中详细阐明了SMAA的独特优点和结构类型．综述在机器人中的应用。     

充分利用市场网络资源构建厂内通信网

为节省网络建设资金，同时保证企业内部通信网络的高效和实用，在组织筹建公司企业内部通信网络时，应充分考虑和合理利用市场上现有的网络资源。文中通过江西东津发电公司的两个成功的组网实例．介绍了这方面的思路和实施经验。