应用AWE技术快速分析二维随机分布介质目标的宽带电磁散射特性

渐近波形估计技术是近年来提出的一种求解宽带电磁散射问题的有效方法,本文将渐近波形估计技术应用到矩量法中,计算了二维随机分布的无耗介质柱的宽带雷达散射截面,计算结果与传统矩量法逐点计算的结果进行了比较,两者吻合良好,而计算效率得到了较大的提高。     

基于改进Hu矩的变电站红外图像特征提取

首先介绍了Hu不变距的相关理论,采用Hu矩对红外图像进行特征提取,并针对提取的Hu矩各分量数值的数量级差别过大,不能同等体现各分量的重要性,以及Hu不变矩对二维离散图像不满足保证缩放不变性的问题,提出了两种改进方法。然后对两种改进方法的尺度收缩性进行比较,采用Matlab实验仿真技术对缩放性能较优的Hu矩改进方法进行了不变性测试并提取特征。     

Distributed fault-tolerant tracking control for heterogeneous nonlinear multi-agent systems under sampled intermittent communications

This paper studies the distributed fault-tolerant control (FTC) problem for heterogeneous nonlinear multi-agent systems (MASs) under sampled intermittent communications. First, in order to estimate the state of leader under sampled intermittent communications, the distributed intermittent observer for each follower is constructed. By using the tool from switching system theory, the estimation error converges to zero exponentially if the communication rate is larger than a threshold value even under the impact of sampled intermittent communications. Then, by applying model reference adaptive tracking technique, a robust FTC protocol is developed to track the distributed intermittent observer. Two algorithms are presented to choose the feedback gain of the distributed intermittent observer and the tracking feedback gain of the fault-tolerant tracking controller. It is proved that the global consensus tracking error is bounded under the developed distributed control protocol. Finally, an example with the coupled pendulums is provided to verify the efficiency of the designed method.     

战略咨询过程中的知识沟通问题研究

从知识管理角度研究了战略咨询过程中的知识沟通问题,提出知识势差、知识惯性的存在以及咨询顾问知识母体的相对不完备性与顾问——客户知识发酵吧的不稳定性导致了沟通障碍,并相应提出了障碍消除机制。在此基础上构建三主体的知识沟通模型,揭示了战略咨询过程中知识沟通的关键控制节点和知识方案产生的动力机制。     

Through-wall radar imaging using UWB noise waveforms

This paper examines the results of our research on the use of ultrawideband noise waveforms for imaging objects behind walls. The advantages of using thermally generated noise as a probing signal are introduced. The technique of heterodyne correlation used to inject coherence in the random noise probing signal and to collapse the wideband reflected signal into a single frequency are presented. Central to successful imaging through building walls is the characterization of the wideband propagation properties of wall materials and these are discussed. The basic concepts of synthetic aperture radar image formation using noise waveforms and the unique problems associated with the random nature of the transmit waveform are analyzed. We also address issues related to locating, detection, and tracking humans behind walls, using new tools for human activity characterization, namely the Hilbert-Huang Transform approach. The results indicate that noise radar technology combined with modern signal processing approaches is indeed a viable technique for covert high-resolution imaging of obscured stationary and moving targets.     

基于Android系统的TCP/IP客户端异步通信模块研究

利用Java多线程以及线程间通信技术实现TCP/IP异步通信存在耦合度较高、模块可重用性低等弱点,采用中介者设计模式进行改进并设计TCP/IP客户端异步通信框架。在家畜养殖智能监控系统的通信模块中对该通信框架进行了验证。结果表明,采用该框架设计的通信模块响应及时、性能稳定。     

Quadratic-exponential moment error bounds for digital communication systems

By utilizing the theory of moment spaces, upper and lower bounds are obtained for error probability of digital communication systems, based on the use ofquadratic- exponential moments of the inter-symbol interference random variables. Some bound can be evaluated numerically with minimal computational effort, while other bounds require more effort. Even the computationally simple bounds can be extremely tight.     

The geometry of linearly and quadratically constrained optimization problems for signal processing and communications

Constrained minimization problems considered in this paper arise in the design of beamformers for radar, sonar, and wireless communications, and in the design of precoders and equalizers for digital communications. The problem is to minimize a quadratic form under a set of linear or quadratic constraints. We present solutions to these problems and establish a connection between them. A majorization result for matrix trace and Poincare's separation theorem play key roles in establishing the connection. We show that our solutions can be formulated as generalized sidelobe cancellers (GSCs), which tie our constrained minimizations to linear minimum mean-squared error (LMMSE) estimations. We then express our solutions in terms of oblique projection matrices and establish the geometry of our constrained minimizations.     

Reproducing kernel resolution space and its applications—II

This paper extends the concept of a reproducing kernel resolution space to a Banach space setting. The resultant reproducing kernel resolution space, however, remains a Hilbert space thereby permitting a number of problems in mathematical system theory to be transformed from Banach space to Hilbert space. Particular emphasis is given to the study of Banach space valued random variables and the scattering operator formalism for an electric network.     

Moments generating function of the harmonic mean of two non-identical gamma random variables and its applications in wireless communications

In this paper, a closed-form expression for the moments generating function of the half-harmonic mean of two independent, not necessarily identically distributed gamma random variables with arbitrary parameters is presented. This statistical result is useful to the performance analysis of dual-hop wireless communication systems with amplify-and-forward relays in a Nakagami-m fading environment. The proposed mathematical analysis is substantiated by various numerically evaluated and computer simulation results.     

A robust unscented transformation for uncertain moments

This paper proposes a robust version of the unscented transform (UT) for one-dimensional random variables. It is assumed that the moments are not exactly known, but are known to lie in intervals. In this scenario, the moment matching equations are reformulated as a system of polynomial equations and inequalities, and it is proposed to use the Chebychev center of the solution set as a robust UT. This method yields a parametrized polynomial optimization problem, which in spite of being NP-Hard, can be relaxed by some algorithms that are proposed in this paper.     

浅谈礼貌原则对跨文化交际的影响

跨文化交际中有许多潜在的障碍。从语用学的角度看．遵循礼貌原则是有效推进跨文化交际的重要手段。然而，札貌原则受到许多因素的制约．具有灵活性和多样性的特点。我们必须研究这些特点，才能使跨文化交际更好的进行。本文从比较中西文化对礼貌原则的评判标准和实施方略的不同入手，详细论述了中西文化中谦逊准别与赞同准则，集体主义与个人主义以及语境对执行礼貌原则的不同影响。阐述了礼貌原则对跨文化交际的指导意义。通过论述，在文章结尾得出结论．文化认同是跨文化交际的语用原则，是执行礼貌原则的前提。只有寻求文化认同，才能更好地利用礼貌原则为跨文化交际的顺利进行服务。     

基于高职聋生语言特点的计算机专业词汇教学研究

计算机词汇手语的缺失、学生地方手语和中国手语的转换以及计算机软件操作步骤繁琐等问题都使聋人学生在计算机软件的学习中存在很多的困难,也给教师的教学、沟通带来一定挑战。教师需要考虑到学生的手语认知程度、词汇识记状态进行操作,更要解决学生的词汇、手语匹配的问题并提高聋生语义理解力。本文参考了普通教学理论和特殊教育理论,结合聋人学生实际教学中表现出的特点,重点论述了计算机教学中沟通方面的常见问题和解决方法。     

大学生人际交往心理障碍及其调适

人际交往问题不仅关系到大学生的学习生涯,更是大学生能否适应社会生活的重要因素。影响大学生人际交往的心理因素主要有院认知偏差、不良情绪、人格差异障碍等,而家庭教育、学校环境以及社会变革的大背景等促成了这些心理因素的产生。因此,从端正认知、驾驭情绪、完善人格、提升沟通技巧方面对人际交往心理障碍进行调适有着较好的针对性和有效性。     

经典DSmT证据组合规则的随机集表示

由于信息的多样性和复杂性,使得对不确定信息的表示和建模都要通过相应的方法完成。由于方法的不统一,难以实现对异类不确定信息的融合。寻找一种统一的理论实现多源异类信息的表示与建模,已成为信息融合领域中的关键问题。已有研究成果表明,随机集理论有望解决该难题。介绍了一种新的不确定推理理论-DSm理论,引入了随机集理论的基本概念和性质,以随机集为工具,给出了经典DSm组合规则的随机集表示,从而将DSmT纳入基于随机集理论的不确定信息统一表示与建模架构中。     

Towards efficient communications in federated learning: A contemporary survey

In the traditional distributed machine learning scenario, the user’s private data is transmitted between clients and a central server, which results in significant potential privacy risks. In order to balance the issues of data privacy and joint training of models, federated learning (FL) is proposed as a particular distributed machine learning procedure with privacy protection mechanisms, which can achieve multi-party collaborative computing without revealing the original data. However, in practice, FL faces a variety of challenging communication problems. This review seeks to elucidate the relationship between these communication issues by methodically assessing the development of FL communication research from three perspectives: communication efficiency, communication environment, and communication resource allocation. Firstly, we sort out the current challenges existing in the communications of FL. Second, we have collated FL communications-related papers and described the overall development trend of the field based on their logical relationship. Ultimately, we discuss the future directions of research for communications in FL.     

城市交通问题刍议

城市交通是人为规划和设计的产物。在城市发展的不同阶段,其交通类型和模式各有不同。在同一个社会发展阶段,各个城市的交通模式也不尽相同,这是由于规划者对城市规划和城市设计理念的差异化认识和应用的结果。现代交通模式的基石实际上是一种功能主义的规划范式。这种交通模式同样带来严重的交通问题,值得认真反思。     

基于RS485通讯有关问题的分析

本文结合实际应用介绍RS-485通信的方法和常用接口芯片的种类和一些常见问题的解决方法。     

财经类专业概率论与数理统计的教学方法探讨

概率论与数理统计是研究随机现象的一门数学学科,在社会经济中应用性较强,与其他学科相比,往往让学生感到难学。因此,教师在教学过程中应运用最佳的教学方法,减轻学生对该门学科的畏惧心理,教会学生科学的思维方法,提高学生理解和分析问题的能力。本文以概率论与数理统计的教学实践为基础,从三个方面结合实例对该课程在财经类专业中的教学方法进行了探讨,以期取得较好的教学效果。     

藏族学生日语话语运用能力的实际问题及根源初探

随着国家的深入开放,西藏和外界交流的加强,日语专业人才逐渐成为了西藏外语人才需求的重要部分,其中对于日语的话语运用能力即听说能力的要求更加明显。本文通过对日语专业藏族学生听说能力的实际调查,找出其问题所在,并探析其问题产生的根源。