通用可靠的串口/以太网网关设计

介绍了一种串口/以太网嵌入式网关的设计方案,详细讨论了串口可靠通信的实现方法,并在开源操作系统RT-Thread和微处理器S3C2440开发板的软硬件平台上实现。网关实际应用于一个无线传感器网络项目,实验表明该网关能实现可靠的数据通信。     

实现多无线接入点网络连接模型的研究

本文提出一种负载均衡模型,此模型不仅考虑AP的信号强度,而且要考虑现有AP已接入无线工作站的数量还有连接质量因素。除此之外,还讨论了实现此模型的无线协议的扩充。     

Stability analysis and H∞ control for hybrid complex dynamical networks with coupling delays

This paper formulates and studies a model of complex dynamical networks with switching topology and coupling delays. Based on the hybrid control and Lyapunov function, the stability and robust H_∞ control of such networks with impulsive and switching effects, which have not been studied before, are addressed with some criteria derived. Examples are given to illustrate the effectiveness of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Integrating local action elements for action analysis

In this paper, we propose a framework for human action analysis from video footage. A video action sequence in our perspective is a dynamic structure of sparse local spatial–temporal patches termed action elements, so the problems of action analysis in video are carried out here based on the set of local characteristics as well as global shape of a prescribed action. We first detect a set of action elements that are the most compact entities of an action, then we extend the idea of Implicit Shape Model to space time, in order to properly integrate the spatial and temporal properties of these action elements. In particular, we consider two different recipes to construct action elements: one is to use a Sparse Bayesian Feature Classifier to choose action elements from all detected Spatial Temporal Interest Points, and is termed discriminative action elements. The other one detects affine invariant local features from the holistic Motion History Images, and picks up action elements according to their compactness scores, and is called generative action elements. Action elements detected from either way are then used to construct a voting space based on their local feature representations as well as their global configuration constraints. Our approach is evaluated in the two main contexts of current human action analysis challenges, action retrieval and action classification. Comprehensive experimental results show that our proposed framework marginally outperforms all existing state-of-the-arts techniques on a range of different datasets.     

Analysis and control of general logical networks – An algebraic approach

Since Boolean network is a powerful tool in describing the genetic regulatory networks, accompanying the development of systems biology, the analysis and control of Boolean networks have attracted much attention from biologists, physicists, and systems scientists. From mathematical point of view, the dynamics of a Boolean (control) network is a discrete-time logical dynamic process. This paper surveys a recently developed technique, called the algebraic approach, based on semi-tensor product. The new technique can deal with not only Boolean networks, which allow each node to take two values, but also k-valued networks, which allow each node to take k different values, and mix-valued networks, which allow nodes to take different numbers of values.The paper provides a comprehensive introduction to the new technique, including (1) mathematical background of this new technique – semi-tensor product of matrices and the matrix expression of logic; (2) dynamic models of Boolean networks, and general (multi- or mix-valued) logical networks; (3) the topological structure of Boolean networks and general networks; (4) the basic control problems of Boolean/general control networks, which include the controllability, observability, realization, stability and stabilization, disturbance decoupling, identification and optimization, etc.; (5) some other related applications.     

Hierarchically Clustered P2P Video Streaming: Design,implementation, and evaluation

P2P based live streaming has been gaining popularity. The new generation P2P live streaming systems not only attract a large number of viewers, but also support better video quality by streaming the content at higher bit-rate. In this paper, we propose a novel P2P streaming framework, called Hierarchically Clustered P2P Video Streaming, or HCPS, that can support the streaming rate approaching the optimal upper bound while accommodating large viewer population. The scalability comes with the hierarchical overlay architecture by grouping peers into clusters and forming a hierarchy among them. Peers are assigned to appropriate cluster so as to balance the bandwidth resources across clusters and maximize the supportable streaming rate. Furthermore, individual peers perform distributed queue-based scheduling algorithms to determine how to retrieve data chunks from source and neighboring peers, and how to utilize its uplink bandwidth to serve data chunks to other peers. We show that queue-based scheduling algorithms allow to fully utilize peers’ uplink bandwidths, and HCPS supports the streaming rate close to the optimum in practical network environment. The prototype of HCPS is implemented and various design issues/tradeoffs are investigated. Experiments over the PlanetLab further demonstrate the effectiveness of HCPS design.     

An altruistic differentiated service protocol in dynamic cognitive radio networks against selfish behaviors

Cognitive Radio (CR), first proposed by Mitola, has the potential to improve spectrum utilization by allowing secondary transmission in licensed primary networks, as long as the secondary transmissions do not interfere with the operation of the primary users (PUs) in the primary network. Although it is fundamental to the viability of this burgeoning technology, security aspects of CR have so far received scant attention from researchers. Initial research on CR has largely focused on the issues of resource allocation, spectrum sensing and management while security considerations are often added as an afterthought. As a result, many proposed solutions for CR, have introduced significant security gaps, intensifying the effects of selfishness, inequity, unavailability, or even malicious behaviors. This has posed challenges to quality-of-service (QoS) provisioning in Cognitive Radio Network (CRN) in the face of various network attacks like node masquerading, packet mislabeling and deliberate packet dropping. Since existing routing protocols assume that nodes will forward packets in good faith, the presence of selfish nodes coupled with the dynamic behavior of PUs can lead to excessive packet losses, high delays or even the complete failure of routing protocols in secondary networks. In this paper, we propose a cross-layer Altruistic Differentiated Service Protocol (ADSP) for the dynamic CRNs to address the QoS provisioning issue in CRNs with selfish nodes coexistence. Simulation results demonstrate that the ADSP can achieve much better performance in terms of lower delay, higher throughput and better delivery ratio for the traffic originating from collaborative nodes compared to other cognitive routing protocols in the presence of selfish nodes.     

SVM-based ontology matching approach

There are a lot of heterogeneous ontologies in semantic web, and the task of ontology mapping is to find their semantic relationship. There are integrated methods that only simply combine the similarity values which are used in current multi-strategy ontology mapping. The semantic information is not included in them and a lot of manual intervention is also needed, so it leads to that some factual mapping relations are missed. Addressing this issue, the work presented in this paper puts forward an ontology matching approach, which uses multi-strategy mapping technique to carry on similarity iterative computation and explores both linguistic and structural similarity. Our approach takes different similarities into one whole, as a similarity cube. By cutting operation, similarity vectors are obtained, which form the similarity space, and by this way, mapping discovery can be converted into binary classification. Support vector machine (SVM) has good generalization ability and can obtain best compromise between complexity of model and learning capability when solving small samples and the nonlinear problem. Because of the said reason, we employ SVM in our approach. For making full use of the information of ontology, our implementation and experimental results used a common dataset to demonstrate the effectiveness of the mapping approach. It ensures the recall ration while improving the quality of mapping results.     

太阳能帆板输出功率短期预测研究

在卫星观测中,经常由于各种原因导致短时间内无法提取目标卫星数据,使控制系统无法继续对其保持高精度跟踪和控制。文章主要研究ARIMA模型在卫星遥测数据短期预测中的应用。使用Matlab软件进行ARIMA模型参数计算,再使用SPSS软件执行数据预测,并进行残差分析,通过实例验证,短时期内的预测数据精度较高。     

基于多信号流模型的模型封装与解包技术

随着科技的快速发展,设备系统的复杂程度越来越高,多信号流模型是系统测试性分析的常用模型,为解决复杂系统建模分析时对其各分系统信息保密问题,提出了一种基于多信号流模型的模型封装与解包方法。该方法首先确定了封装模块数据信息并实现封装,然后构建封装模块测试信息描述表,描述了封装模块内部故障、内部测试与外部信息的关系以及封装模块本身对外部信息的影响,实现了模块的解包。实验表明,该描述方法可以有效地屏蔽了被封装的分系统模型的技术信息,有利于各分系统设计者之间的信息保密,同时利用该描述方法,还可以有效地减少测试性分析所需的时间。