机车空调逆变电源设计

本文讨论的是机车空调逆变电源系统的设计与研究。该电源系统主要是由DC/DC的BOOST升压部分和DC/AC三相逆变部分两部分组成。DC/DC部分所得直流电压通过DC/AC部分逆变成三相交流电,供给空调机组工作。同时,为使电源系统能更可靠的运行,也设计了相应的故障检测、保护等辅助电路。     

Abstraction of levels of abstraction

The notion of level of abstraction (LoA) is one of the foundations of the Floridi's Philosophy of Information. It also serves for many practical purposes as in information ethics. But the notion of abstraction is not new; it has been given many different meanings in various fields, especially in scientific disciplines and, in particular, in computer science. Our purpose here is to examine the use of abstraction in Floridi's works in conjunction with some of the meanings of abstraction in computer science. The article is divided into five sections. After a general introduction to the Floridi's method of abstraction (MoA) in Section 1, Section 2 revisits Floridi's definition of abstraction and Section 3 gives the different senses of abstraction in computer science. The Section 4 compares them with the Floridi's LoAs and proposes to generalise the Floridi's approach to abstraction using an abstraction of the LoAs, while Section 5 concludes on what we think to be some new arguments in favour of MoA and LoA.     

Synthesis of subminimum-time bounded control of system of rigid bodies

An algorithm of control of a system of rigid bodies in a form of feedback in special coordinates is discussed. The control is bounded, and it is also subminimum-time in the sense that it coincides with the optimal in linear approximation and in the case of a system with one degree of freedom. It is shown that the controller endows the unperturbed motion of the system with the property of asymptotic stability in large and is also robust. The results of numerical experiments, demonstrating the closeness of the trajectories to the time-optimal ones, are presented.     

手腕骨X线片兴趣区域图像分割的研究

提出了一种准确分割骨骺兴趣区域边缘位置的方法。针对手腕骨X线片图像的特征,采用Gibbs 随机场对兴趣区域进行初始分割,将骨从图像中分割出来;针对骨与软组织的灰度值相差不大,Gibbs 随机场正确分割困难的问题,再进一步利用主动轮廓法对初始轮廓进行改善,将软骨与软组织准确分割开,从而得到了正确的骨的边缘位置。实验验证了该方法对分割出的底部区域骨的轮廓线有较大的改善,同时这种联合的方法具有较强的抗噪声能力。     

传输线信号完整性的反射分析

针对高速电路系统的传输线信号完整性问题,通过对高速电路PCB上传输线等效电路的分析,给出了信号传输时产生反射现象的原因;介绍了常用的消除反射的方法,即选择均匀传输线、采用合适的拓扑结构布线和阻抗匹配法,指出阻抗匹配法可解决信号传输的反射现象;阐述了源端阻抗匹配法和负载端阻抗匹配法消除反射的原理和适用条件。针对时钟电路中的反射问题,采用PADS/Hyperlynx软件对阻抗匹配法进行仿真,结果表明,阻抗匹配法能够改善信号传输的反射现象。     

深圳市景观格局空间梯度分异的研究

选择深圳市作为研究对象,利用2006年的遥感影像,研究了深圳市景观空间格局的梯度变化特征。结果表明：景观多样性指数沿梯度区呈先增大后减少的趋势。在城区内其值较低,在城乡结合区域因类型斑块交错分布其值较高;在城区景观斑块密度与边缘密度较小,景观异质性较低。越靠近城乡结合处景观异质程度越大。从景观平均形状指数和景观平均分维数的变化,可看出人为活动的干扰由市中心向郊区发展是呈增强的趋势。以上分析表明景观格局的空间分布与受人为干扰程度有重要的联系。     

On the problem of identification of the authors of Russian publications

We present the results from a study of the array of Russian publications present in Web of Science in order to reveal the actual number of Russian scientists who participated in the process of writing them. We suggest algorithms and methods of identifying the authors and assessed the efficiency of these methods.     

Classifying the subjects of the Russian Federation on the basis of analysis of results of Gallup polling

The problem of processing of Gallup poll results by cluster analysis methods is considered. The aim of these polls, performed in different subjects of the Russian Federation, is to extract main characteristics of the regions. Demyanov Egor A. Born 1982. Graduated from the Moscow State University in 2004. Post-graduate student of the same university. Scientific interests: discrete mathematics and mathematical methods of pattern recognition. Author of two publications. Djukova Elena V. Born 1945. Graduated from the Moscow State University in 1967. Received candidate’s degree in Physics and Mathematics in 1979, Doctoral degree in Physics and Mathematics in 1997. Dorodnicyn Computing Center, Russian Academy of Sciences, leading researcher. Moscow State University, lecturer. Moscow Pedagogical University, lecturer. Scientific interests: discrete mathematics and mathematical methods of pattern recognition. Author of 76 papers. Peskov Nikolai V. Born 1978. Graduated from the Moscow State University in 2000. Received candidate’s degree in Physics and Mathematics in 2004. Dorodnicyn Computing Center, Russian Academy of Sciences, junior researcher. Scientific interests: discrete mathematics and mathematical methods of pattern recognition. Author of 17 papers. Inyakin Andrey S. Born 1978. Graduated from the Moscow State University in 2000. Received candidate’s degree in 2006. Dorodnicyn Computing Center, Russian Academy of Sciences, junior researcher. Scientific interests: discrete mathematics and mathematical methods of pattern recognition. Author of 16 papers.     

煤矿安全监控系统数据接口标准的研究

煤矿现有安全监控系统种类多,传输协议、格式、内容不统一,各个厂商生产的安全监控系统中所使用的接口、标准和协议也不尽相同,很难实现安全监控系统的数据共享、信息应用集成以及煤矿安全远程监控和联网。针对上述问题,提出了煤矿安全监控系统数据接口标准的设计方案,分析了该数据接口标准建设的目的及原则,详细介绍了该数据接口标准的3个组成部分即信息分类编码、文本格式的数据文件和XML格式的数据文件的结构及作用。该数据接口标准的应用能够统一煤矿安全监控系统数据交换的内容和格式,从而实现煤矿各级管理部门的数据共享和数据交换。     

支持向量机多类目标分类器的结构简化研究

由于支持向量机(SVM)在模式识别和回归分析中有着独特优势，因此成为近来研究的热点，其优势主要体现在处理非线性和高维数据问题方面。最初的SVM特别适合解决两类目标分类问题，而对于多类目标分类，则需将其转化为多个两类目标分类问题，相应地即可构造多个两类目标子分类器，但由于这种情况导致了分类器结构的过于复杂，从而导致判决速度的降低。为了快速地进行分类．提出了一种简化结构的多类目标分类器，其不仅使得子分类器数目大大减少，而且使分类速度明显提高；同时对其分类精度和复杂度进行了对比分析。实验结果证明。该分类器是有效的。     

论RFID运用于物联网的局限性

介绍物联网发展,分析RFID技术在物联网中的作用与地位.从RFID技术本身及其工程应用出发,探索现在国内RFID产业发展中存在的一些问题,并提出相应的解决建议.最后,结合实际有源RFID工程实施中出现的问题,思考其发展前景.     

物联网技术在智慧校园建设中的应用

在信息化的时代背景下,信息技术在各行各业中广泛应用,并取得了较好的成效。目前,信息技术在校园生活中广泛渗透,特别是物联网的快速发展为智慧校园的建设提供了重要的技术支持。文章从物联网与智慧校园入手,分析了智慧校园建设中的主要物联网技术,并进一步阐述了物联网技术在智慧校园建设中的应用及发展方向。     

物联网技术研究进展

目前,物联网因其巨大的应用前景而受到各国政府、学术界和工业界的广泛重视,成为国内外信息通信领域的新研究热点;物联网产业己经成为推动世界经济增长的重要新兴产业,我国已将物联网的发展列为信息产业发展的下一个战略高点;首先总结了物联网的国内外研究进展,其次对物联网的概念、实现原理与体系结构进行了分析,归纳了物联网涉及的关键技术,然后介绍了物联网的一些典型应用,最后指出了物联网进一步研究的方向以及制约国内物联网发展的问题及解决对策。     

液压支架电液控制系统软件在线升级方案设计

针对现有液压支架间架控制器与端头控制器的软件升级需要技术人员在井下对控制器逐一拆装操作,且耗时长、效率低的问题,提出了一种液压支架电液控制系统软件在线升级方案,详细介绍了液压支架电液控制系统组成、代码存储空间变化及在线升级的相关程序流程,并给出了实验数据及分析。该方案实现了对间架控制器和端头控制器的远程在线升级,升级过程简单方便,且升级速度快。     

Computational properties of networks of synchronous groups of spiking neurons

We demonstrate a model in which synchronously firing ensembles of neurons are networked to produce computational results. Each ensemble is a group of biological integrate-and-fire spiking neurons, with probabilistic interconnections between groups. An analogy is drawn in which each individual processing unit of an artificial neural network corresponds to a neuronal group in a biological model. The activation value of a unit in the artificial neural network corresponds to the fraction of active neurons, synchronously firing, in a biological neuronal group. Weights of the artificial neural network correspond to the product of the interconnection density between groups, the group size of the presynaptic group, and the postsynaptic potential heights in the synchronous group model. All three of these parameters can modulate connection strengths between neuronal groups in the synchronous group models. We give an example of nonlinear classification (XOR) and a function approximation example in which the capability of the artificial neural network can be captured by a neural network model with biological integrate-and-fire neurons configured as a network of synchronously firing ensembles of such neurons. We point out that the general function approximation capability proven for feedforward artificial neural networks appears to be approximated by networks of neuronal groups that fire in synchrony, where the groups comprise integrate-and-fire neurons. We discuss the advantages of this type of model for biological systems, its possible learning mechanisms, and the associated timing relationships.     

电力物联网下无线传感器网络位置隐私保护方法研究

首先对无线传感器网络的概念及其在电力物联网中的应用进行了简单的介绍,指出了无线传感器网络中存在的隐私问题;其次针对位置隐私保护进行了概述,并给出了攻击者模型;接下来,分别介绍了几种源节点位置隐私保护和汇聚节点位置隐私保护技术,并对它们的性能进行了分析和比较;最后,我们对电力物联网中的无线传感器网络位置隐私保护技术所需考虑的问题提出了见解和建议.     

An analysis of the use of virtual delivery of undergraduate lectures

Educators and technologists have been wrestling with the most appropriate way in which to use information technology in teaching and in learning, for some years. We have seen online course notes, both linear, hypertext and hypermedia format, lecturer/student communication via electronic bulletin boards or via e-mail, multimedia courseware with student-directed learning and many others. All of these approaches have had limited impact on mainstream teaching in our universities and colleges and we believe one of the reasons for this is that these attempts all represent a significant shift in the normal student–lecturer relationship and an enormous amount of effort on the part of the lecturer. In our work we have addressed this by using technology to replicate the traditional mode of delivery of lectures to a class. The presentation of lecture material was digitally recorded, both audio and synchronised visuals, and made available for students to take in their own time. In addition we provided 3 orthogonal means to access this material. The present paper describes our analysis of the use of these `virtual lectures' by a class of over 100 students. Our analysis includes log files of all accesses to the online material, pre-course and post-course questionnaires and anonymous questionnaire feedback, some of this is compared to exam performance. Results indicate that mode of delivery, student usage and a student's technical bias have no impact on overall exam performance.     

编码器倍频、鉴相电路在FPGA中的实现

VHDL是系统设计领域最佳的硬件描述语言。文章针对用于位置与速度反馈测量的光电编码器信号的特点,介绍了运用VHDL在FPGA中实现编码器倍频、鉴相电路的方法,它对提高编码器分辨率与实现高精度、高稳定性的信号检测及位置伺服控制具有一定的现实意义。