模糊合作博弈及其广义核心解的应用研究

为了解决模糊合作博弈传统核心解在资源分配问题中的应用局限,提出了对模糊合作博弈(N,v)中总收益值v(e~N)进行保留,不将全部总收益值分配给所有参与者,进而实现资源再分配或再发展的方案,进一步适应模糊合作博弈核心解的应用需求.首先定义了广义转归、广义核心,广义稳定集等解的概念,然后指出了其含义,在此基础上描述了模糊合作博弈模型.最后以定理证明了各广义核心解之间的关系,说明通过相应系数的调整即可提供合理的分配方案,表明了推广后的模糊合作博弈核心解具有更高的理论及应用价值.     

一种基于系统总误码率的协同伙伴选择算法

提出了一种基于系统总误码率的协同伙伴选择算法。当系统总发送功率一定时,通过系统误码率公式,采用带CRC校验的DF协同通信的协同增益,来降低系统总的误码率。仿真表明,此算法有效地降低了系统总误码率,并且系统SNR越大,协同通信对系统数据传输的帮助越明显。     

ORACLE数据库系统安全探讨

数据库安全问题一直是困扰数据库管理员的主要问题,针对Oracle数据库中的安全问题,总结了Oracle中必要的安全设置,并对数据库安全的自动预警提出了可行的策略。     

Deployment algorithms for a power‐constrained mobile sensor network

This paper presents distributed coverage algorithms for mobile sensor networks in which agents have limited power to move. Rather than making use of a constrained optimization technique, our approach accounts for power constraints by assigning non‐homogeneously time‐varying regions to each robot. This leads to novel partitions of the environment into limited‐range, generalized Voronoi regions. The motion control algorithms are then designed to ascend the gradient of several types of locational optimization functions. In particular, the objective functions reflect the global energy available to the group and different coverage criteria. As we discuss in the paper, this has an effect on limiting each agent's velocity to save energy and balance its expenditure across the network. Copyright © 2009 John Wiley & Sons, Ltd.     

A real-time versatile roadway path extraction and tracking on an FPGA platform

This paper presents an algorithm for roadway path extraction and tracking and its implementation in a Field Programmable Gate Array (FPGA) device. The implementation is particularly suitable for use as a core component of a Lane Departure Warning (LDW) system, which requires high-performance digital image processing as well as low-cost semiconductor devices, appropriate for the high volume production of the automotive market. The FPGA technology proved to be a proper platform to meet these two contrasting requirements. The proposed algorithm is specifically designed to be completely embedded in FPGA hardware to process wide VGA resolution video sequences at 30 frames per second. The main contributions of this work lie in (i) the proper selection, customization and integration of the main functions for road extraction and tracking to cope with the addressed application, and (ii) the subsequent FPGA hardware implementation as a modular architecture of specialized blocks. Experiments on real road scenario video sequences running on the FPGA device illustrate the good performance of the proposed system prototype and its ability to adapt to varying common roadway conditions, without the need for a per-installation calibration procedure.     

认知无线电系统协作频谱感知机制优化

为使干扰受限情况下的频谱感知效率达到最大,提出一种认知无线电系统协作频谱感知机制的优化方案。定义系统模型,运用协作频谱感知对系统目标进行联合优化,包括感知时间、传输时间、参与协作的感知用户数在内的感知参数优化。仿真结果证明,采用该优化方案,能在满足干扰受限的条件下最大化频谱感知效率。     

多星系统相对轨道的自适应协同控制

基于一致性理论,在无向拓扑结构上对多星系统相对轨道的协同控制问题进行了研究.本文考虑近地卫星相对轨道的非线性方程,首先设计控制律使得多星系统形成目标队形,并给出了速度阻尼和通信拓扑(相对速度间的拓扑关系)连通性之间的关系;其次,针对卫星质量具有不确定性的情形,设计了新的辅助变量,提出了自适应的协同控制律,这里要求传感(相对位置间的拓扑关系)和通信具有相同的拓扑结构.最后对4颗卫星的编队飞行进行了仿真分析,仿真结果表明本文设计的协同控制律是有效可行的.     

Performance analysis and partner selection for cooperative diversity based on MQAM modulation

An adaptive decode-and-forward (DF) cooperative diversity system based on quadrature modulation is proposed, in which each user is allowed to transmit its own and the partner’s data simultaneously via the in-phase and quadrature components of M -ary quadrature amplitude modulation (MQAM) constellation. Cooperative transmission in this way can avoid the bandwidth expansion in traditional cooperative systems. The closed form expression of the average bit error rate (BER) performance is derived in terms of the...     

基于车辆自组网络的分布式自主导航系统

针对交通拥堵和道路安全问题,在车载自组网路由协议改进和实现的基础上,提出一种基于车辆自组网络的分布式智能交通服务系统,实现邻域动态路况展示、突发交通事故预警和交通图片视频信息分发等自主交通导航服务。与传统后台计算动态交通服务实现方式相比,车辆自组网能较好地发挥其在车辆问直接交互交通、安全、娱乐等实时信息的优势。