摘要：针对对等网络(peer to peer,P2P)中资源搜索效率低的问题,提出一种基于节点信誉改进Q学习的资源搜索策略(search strategies using improved Q-learning based on node reputation,SSQBR).该策略在Q学习模型基础上通过引入信誉机制,在搜索初期通过选择信誉值最高的邻居节点转发查询请求以解决Q表的资源信息不足时搜索成功率低的问题,该策略加速了Q学习过程,提高了资源搜索的成功率.仿真结果表明,改进的资源搜索策略与其他搜索策略法相比,可有效降低资源搜索响应时间,提高搜索成功率.
摘要：分析了Ka频段卫星通信的信道特性与模型,对基于小波包分复用(wavelet packet division multiplex,WPDM)的Ka频段卫星传输系统进行了研究;并采用支撑长度低的小波函数来降低系统的高峰均功率比(peak to average vatio,PAPR).仿真结果能和该系统的误码率分析结果很好地吻合,并通过与OFDM(orthogonal frequency division multiplex)系统仿真对比得到在误码率为10-3时可节约3 dB;且显示出支撑长度低的小波函数能有效降低系统峰均功率比,从而提高系统性能.
摘要：多路径传输协议(multipath transmission control protocol,MPTCP)是一种基于TCP协议的传输协议,具有高吞吐量、高带宽利用率、高传输速率等优点,且MPTCP向后兼容TCP,支持现有中间件.针对导致MPTCP的传输性能下降的MPTCP中出现乱序、缓存阻塞等问题,综合考虑每条子路径的往返时延RTT(round trip time)和接收端成功接收到的数据包个数,设计了一种动态预留数据调度算法(dynamic resource reservation data scheduling,DR-RS),当每次需要传输数据包时,子路径的发送缓存按照合理的策略为所需传输的数据包预留空间,尽量使数据包能够按序到达接收端,避免接收端缓存阻塞.利用NS-3仿真工具,对比分析了DR-RS性能,结果表明,DR-RS更合理,能使MPTCP的传输更稳定并提高了传输吞吐量,达到了负载均衡.
摘要：When cognitive relay network aims at voice communication, there is a need for better maximizing of its throughput with minimal cost of power. A game theory model of power control with nonlinear pricing function is introduced after an analysis of the network in depth. Its solution of nash equilibrium depends on channel parameter and pricing parameter. This method of power control is more matchable to the network. It can decrease power consumption and boost energy efficiency of the network. In the meantime, it is also capable of lowering complex degree in realization of power control. Comparison of methods with two different price coefficient and simulation show that the method can get better performance of communication.%当认知中继网络被应用于语音通信时,要求最大化网络吞吐量的同时使功率消耗较小.分析研究了认知中继网络的通信特点,提出一种基于非线性价格成本函数的认知中继网络功率控制博弈模型,其纳什均衡解直接决定于信道参数和价格系数,该功率控制方法更符合网络的特点,减少了网络的功率消耗,提高了能量效率,同时降低了功控实现的复杂度.通过分析比较其他两种价格系数的情况,最后仿真结果验证了该功率控制方法能达到较好的通信性能.
摘要：This paper defines the personality space, the mood space and the emotion space based on the theory of affective computing and artificial psychology, and establishes the mapping relationship between the personality space and the mood space. It gives the concept about the intensity of basic emotion to describe the state of the emotion space in a certain moment. Then through using the distance about the mood vector of the mood space to the point of basic emotion to measure the probability of sort of emotion appearing in the emotion space, it structures a mapping relationship between the mood space and the emotion space. It constructs a new personalized affective model that has three level mapping. Simulation result shows that the model can describe the change law of human emotion.%基于情感计算和人工心理学理论定义了个性空间、心情空间和情感空间,并建立起了个性空间同心情空间的映射关系,提出基本情感强度的概念来描述情感空间在某一时刻所处的状态.根据心情空间中心情向量离基本情感点的距离远近关系来度量情感空间中某种情感出现的概率大小,建立起了心情空间与情感空间的映射关系,并建立了一个新的三层映射关系的个性化情感模型.通过仿真实验验证,该情感模型能较为准确地描述人类情感变化规律.
摘要：Extracting the optimal discriminating characteristics is an important step of finger vein recognition. In extracting the image feature of high dimensional finger vein of small samples, the influence of the light, temperature, humidity and horizontal displacement makes the acquisition of the vein image's distribution nonlinear. Therefore, a method based on nuclear Fisher's (Kernel Fisher discriminant analysis, KFDA) differential analysis to extract the nonlinear characteristics is put forward. This method uses a nuclear mapping to change the original input space to a more low-dimensional space,using the dispersion matrix between the nuclei as the Fisher( Fisher linear discriminant, FLD) standard to get the best nonlinear differential features, Finally, according to the identification of characteristics the determination is done by using the calculation of the Euclidean distance between each other . The experimental results show that the method of nuclear has the lower recognize false rate FAR( false accept rate) and faster speed of recognition than other methods.%抽取最优鉴别特征是手指静脉识别中重要的一步,在提取小样本的高维手指静脉图像特征时,由于光照、温湿度、水平位移等因素的影响使得采集的静脉图像是非线性分布的,为此,提出了一种基于核Fisher鉴别分析(kernel Fisher discriminant analysis,KFDA)提取非线性特征的方法.该方法是利用一个核映射将原始输入空间变换到一个更低维的空间RN中,在此特征空间上用核类间散度阵和核类内散度阵作为Fisher线性判别准则(Fisher linear discriminant,FLD),来得到最佳非线性鉴别特征,根据此鉴别特征计算其相互间的欧式距离进行识别.实验结果表明,核Fisher方法与其他方法相比,具有较低的认假率(false accept rate,FAR)和较快的识别速度.
摘要：在分布式多天线的基础上,提出一种新型非视距误差消除算法,并将其应用于传统的时间到达(time of arrival,TOA)定位.利用含多天线的天线组,测量出导致产生非视距传播的散射体的位置,将这些散射体看作虚拟基站,测量出移动台的坐标,完成无线定位.通过对算法的仿真结果分析表明,该算法能有效地消除非视距误差,比一些传统算法具有更高的定位精度.%It has a very important influence on positioning accuracy. This paper discusses a distributed multi-antenna based NLOS error elimination algorithm applied to the traditional localization method of TOA. The algorithm firstly estimates the position of the scatterers which cause the NLOS propagation by different antennas in one multi-antenna array. Then the estimated scatterers can be employed as virtual base station to calculate the position of the mobile station. The experiment results show that the proposed algorithm can eliminate NLOS error effectively. The location accuracy is greatly improved compared with other two conventional localization methods.
摘要：To overcome the problem of coverage of underlay in cognitive radio networks, a multi-cell spectrum handoff scheme based on evaluation of coverage of underlay is proposed. Simple additive weights decision algorithm with dynamic weights ( SAW-DW) in spectrum handoff is used to select a best target cell for continuing data transmission when secondary users exceed underlay constraint. Theoretical analysis and simulation results show that the scheme and algorithm can reduce probability of handoff failure and probability of service interrupt of secondary users and improve quality of service of secondary users.%为了克服认知无线电网络中衬垫传输覆盖范围的限制,基于对衬垫传输范围的估计,提出了多小区的频谱切换机制.当认知用户超出衬垫传输范围时,采用动态权值调整的简单加权判定算法选择最优目标小区,进行频谱切换,继续保持数据传输.理论分析和仿真结果表明,该方案和算法能够降低认知用户的切换失败概率和服务中断概率,提高认知用户的服务质量.
摘要：LT数字喷泉编码所采用的度分布是影响译码效率的关键因素.给出了一种改进的LT数字喷泉编码的度分布,即开关度分布,它结合鲁棒孤子分布和二进制指数分布的优点,可以产生足够多的度很小的编码数据包,减少了译码器启动译码过程所需要的编码数据包的数量,而且减少了译码器成功译码时所需要的编码数据包的总数量.通过仿真给出了最佳的开关点参数.仿真显示,与鲁棒孤子度分布和二进制指数度分布相比,采用开关度分布,明显改善了译码效率.%The degree distribution applied in the LT digital fountain code encoder is a key factor to the decoding efficiency. This paper presents an improved degree distribution which is called Switch Distribution. It combines the advantages of binary exponential distribution and robust soliton degree distribution. When the degree of the coded packets is chosen from Switch Distribution, it can generate enough encoded packets with small degrees. This distribution decreases the number of encoded packets when the decoding process firstly starts and decreases the number of source transmitted packets for recovering the source information successfully at the distination. We obtain the best switch point by simulation. Compared with u-sing Robust Soliton Distribution and Binary Exponential Distribution, using Switch Distribution can greatly increase the decoding efficiency.
摘要：在高速通信过程中,数据处理系统通常需要数据缓存来实时存储收到的数据.利用现场可编程门阵列(field programmable gate array,FPGA)内部资源构建的先进先出(first in first out,FIFO),其容量有限,在数据通信过程中由于读写速度不匹配而导致FIFO溢出,从而出现丢数现象.为此设计并实现了一种三级缓存结构,在FPGA外部引入1 MByte容量的静态随机存储器(static random access memory,SRAM)作为中间级缓存,输入级和输出级缓存为FPGA内部的FIFO,FPGA控制数据的传榆和对SRAM的读写操作.采用三级缓存技术,简化了硬件复杂度,提高了设计的可实现性,经多次测试表明,本技术稳定可靠.%In the high-speed communication,data process system usually needs data buffer to store data timely. The FIFO which is structured by using the internal resources of field programmable gate array (FPGA) has limited capacity, which easily leads to the overflow of FIFO and data discarded, if the speed of reading does not match the speed of writing. To resolve this problem,this paper designs and realizes tri-stage buffer. A SRAM whose capacity is 1MB is added to the exterior of FPGA as the middle buffer. The input buffer and output buffer are the FIFO of FPGA, and FPGA controls the data transmission and the writing and reading operation of the SRAM. Adopting tri-stage buffer technique simplifys the complexity of the hardware and increases the reachability of the design. Tests show that tri-stage buffer technique is reliable and steady.
摘要：针对无线通信系统中下行同步序列(summarized the existing downlink synchronization sequence,SYNC_DL)的搜索方法和对其计算复杂度方面存在的问题进行了分析.结合系统帧结构的特点,设计了一种基于逻辑特征窗的低复杂度SYNC_DL搜索方法,该方法通过逻辑特征窗的设置,将大量的数值计算转化为逻辑运算,从而减少了计算量.数值仿真结果表明,与传统方法相比,该方法在高信噪比环境下能更有效地进行下行同步序列的搜索,但在低信噪比环境下,该方法的正确率会明显降低.%In this paper,we summarized the existing downlink synchronization sequence(SYNC_DL) searching methods in wireless communication system and analyzed the problem of computational complexity. According to the characteristics of the system frame structure, a kind of SYNC_DL searching scheme based on the logical characteristic window which can reduce the computational complexity is designed. By setting logical characteristic window, this method transforms mass numerical computation into logical computation which can reduce the computational complexity . The simulation results reveal that this method can complete downlink synchronization sequence searching more efficiently than traditional methods in high SNR environment,but the success ratio will decline obviously in low SNR environment.
摘要：针对入侵检测中普遍存在检测率低与误报过高的问题,采用基于多维-隐马尔可夫模型的检测方法和基于Apriori算法的误用检测技术相结合的入侵检测系统(intrusion detection system,IDS)模型.新模型减少了单纯使用某种入侵检测技术时的漏报率和误报率,同时在异常检测模块中采用了隐马尔可夫与简单贝叶斯分类器相结合的新检测方法,用来处理具有时间相关的多维度序列,从而提高系统的安全性和检测效率.使用KDD Cup99数据集进行效果评估证明:新的模型系统检测率为93.12％,而误报率为0.46％,能有效检测网络数据中的入侵行为.%Aimed at low detection rate and high false positive rate problems which are widespread in intrusion detection system, an intrusion detection system (IDS) model was combined by the detection method based on multi-dimensional-hidden Markov model and misuse detection technology based on Apriori algorithm. The false negative rate and false positive rate were reduced by the new model when a simple intrusion detection technology was used, meanwhile, a new detection method which was integrated by Hidden Markov and simple Bayesian classifier in the anomaly detection module was put to use, multi-dimensional sequence which has time correlation was dealt with by it, thereby it enhanced system security and detection efficiency. Result evaluations by using KDD Cup99 data sets show that: detection rate of new model systems is 93. 12% , false positive rate is 0. 46% , and it can detect intrusion behavior of network data effectively.
摘要：Came theory-based dynamic spectrum allocation of cognitive radio is one of the hot research of cognitive radio. Taking into account differences of the spectrum, using a Cournot game model, and adding the spectral similarity matrix to the original pricing function, a new utility function that makes the spectrum allocation more close to the actual network environment is proposed. Performance analysis shows that, the allocation algorithm considering the differences in the spectrum is more diverse than the original algorithm, and is suitable for the actual network.%基于博弈论的认知无线电动态频谱分配,是目前认知无线电领域研究的热点之一.考虑到频谱差异性,采用古诺博弈( Cournot game)模型,在原有的定价函数中加入频谱相似度矩阵,提出了新的效用函数,使得更接近于实际网络环境.性能分析表明,考虑了频谱差异性的分配算法较原来算法更具多样性,适合实际网络分配.
摘要：利用有向图生成树算法思想,将寻找搭线窃听下单源单宿网络拓扑图中安全路径的算法推广到单源多宿网络情况.接着以线性网络编码的代数构造方法为背景,对多播网络下的搭线窃听攻击做了详细分析,并结合弱安全网络编码的思想,提出一种改进的线性网络编码代数构造方法,利用该方法,即使网络拓扑图中不存在从源到宿的安全路径,网络也能达到弱安全.%First, using the idea of directed graph spanning tree algorithm, the algorithm for safety path searching in single source single sink network under wiretapping is extended to the situation of single source multi-sink network. Then, in the context of algebraic construction of linear network coding, a detailed analysis of multicast network under wiretapping attack is given. Finally, an improved algebraic construction algorithm for linear network coding which combines the idea of weak network coding is proposed. With the using of this improved method, weak network security can be guaranteed at least, e-ven if there is no safety path from the source to the sink.
摘要：针对多普勒频移严重影响Ka频段正交频分复用(orthogonal frequency division multiplexing,OFDM)系统传输性能的问题,提出使用分数阶傅里叶变换(fractional Fourier transform,FRFT)的方法.将多普勒频移引入Ka频段移动卫星信道模型,通过选取不同环境下的最优阶次,分析了本系统对抗多普勒频移的优势,并对其进行不同条件下的分数阶傅里叶域和频域均衡.仿真结果表明:1)多普勒频移越大,本系统性能改善越明显；2)在最优阶次下,本系统在不同环境中较频域均有更好的均衡效果.%Concerning the negative influence of Doppler shift on OFDM system in Ka-band, FRFT-OFDM system is proposed. A mobile satellite channel model in Ka-band with Doppler shift is established. After the optimal orders of FRFT in different conditions being selected, the advantage of this system on anti-Doppler-shift is analyzed. The system is equalized both in fractional Fourier domain and Fourier domain. The simulation results show that 1 )the more serious Doppler shift is, the more obviously this system performance would be improved ;2) the proposed system under optimal order has better performance of equalization than the traditional system in different conditions.
摘要：针对红外焦平面阵列(infrared focal plane arrays,IRFPA)响应输出易受到环境温度变化的影响,且长时间工作后易发生温度漂移,导致红外热成像系统测温误差大,为此提出了一种红外热成像系统温度漂移补偿算法.该算法建立了红外焦平面阵列响应输出随环境温度变化的补偿模型,利用该模型对IRFPA每个像素响应输出值进行逐一修正.将该补偿算法加入红外热成像系统中,进行红外目标的温度显示实验.实验结果表明,该算法能够有效减少环境温度变化引起的测温误差,提高红外热成像系统的测温精度.%Influenced by environmental temperature, infrared focal plane arrays (IRFPA) response output has obvious temperature drift after working for a long time, which causes larger temperature measurement error of infrared thermal imaging system(IT IS). Therefore, a temperature drift compensation algorithm of IT IS is presented. The algorithm establishes a temperature compensable model for IRFPA response output drift with the environmental temperature, which can correct the drift value of every detector response output. With this compensation algorithm, some infrared object temperature display experiments in IT IS have been done. The experimental results show that the algorithm can effectively reduce temperature drift caused by the environmental temperature, and temperature measuring accuracy of IT IS can be greatly improved.