Enabling Energy Efficient Sensory Data Collection Using Multiple Mobile Sink

Mobile sink is the challenging task for wireless sensor networks （WSNs）. In this paper we propose to design an efficient routing protocol for single mobile sink and multiple mobile sink for data gathering in WSN. In this process, a biased random walk method is used to determine the next position of the sink. Then, a rendezvous point selection with splitting tree technique is used to find the optimal data transmission path. If the sink moves within the range of the rendezvous point, it receives the gathered data and if moved out, it selects a relay node from its neighbours to relay packets from rendezvous point to the sink. Proposed algorithm reduces the signal overhead and improves the triangular routing problem. Here the sink acts as a vehicle and collect the data from the sensor. The results show that the proposed model effectively supports sink mobility with low overhead and delay when compared with Intelligent Agent-based Routing protocol （IAR） and also increases the reliability and delivery ratio when the number of sources increases.     

一种基于改进RANSAC的红外图像拼接方法

在一般的红外图像拼接过程中,采用传统随机抽样一致(RANSAC)方法,耗时往往会稍长。为了缩短图像拼接所耗费的时间,提出了基于尺度不变特征转换(SIFT)和改进RANSAC的图像拼接方法。先通过SIFT得到特征点和特征描述,然后用改进的RANSAC对不匹配的特征点进行剔除,通过得到的变换矩阵完成图像的融合。在改进RANSAC中,设置0.95和0.85两个阈值,少量迭代后,选择跳出循环、重新选择或者计算出新的迭代次数,新的迭代次数必定比传统迭代次数小,因而达到减少时间的效果。红外图像拼接后,把实验结果与采用传统RANSAC算法的结果进行多方位比较,可以发现本文方法能够达到减少时间的目的。     

An Improved Chua's Circuit and Its Use in Hyperchaotic Circuit

An improved implementation of Chua's circuit using dual output current conveyor is presented. The present proposal offers the advantages of low component count, current mode processing, availability of current across inductor and availability of voltage across inductor in form of current. The application of present circuit in designing low hardware inductorless hyperchaotic circuit is also presented. The paper concludes with a discussion of advantages of present proposal of Chua's circuit and inductorless hyper chaotic circuit thus designed over their earlier counterparts. The designs are adequately supported by SPICE simulation results. Patent pending.     

基于大数据挖掘分析的垃圾短信治理方案

本文简要介绍了垃圾短信对社会带来的负面影响,分析了目前垃圾短信治理体系存在的不足,提出了基于大数据挖掘分析的垃圾短信治理方案:首先构建垃圾短信用户识别指标体系,通过引入随机森林模型,对垃圾短信用户进行识别和有效治理,最后运用平台对垃圾短信用户进行精细化管理。     

640×512焦平面读出电路设计

介绍了640×512电容反馈跨阻放大器(CTIA)型焦平面读出电路的设计,包含模拟电路与数字模块设计。分析了CTIA采样单元的设计,折中优化了采样单元的面积、噪声、增益等因素,同时优化了采样单元控制电路,最大限度地提高了对采样单元阵列的驱动能力;数字控制部分着重分析了对行选、列选、翻转读出、随机开窗、隔行扫描、多路选择输出等功能的实现方式。设计基于0.5μm DPTM工艺进行仿真验证,采样单元面积为25μm×25μm,工作频率为5MHz,芯片面积为18.1mm×17.4mm,输出摆幅大于2.5V,动态范围大于70dB。     

CRSF攻击机制及防御策略研究

跨站点请求伪造（Cross—Site Request Forgery）是一种互联网上广泛存在的网络攻击,它通过第三方伪造用户请求来欺骗服务器端,达到冒充用户身份、行使用户权利的目的。文中通过分析跨站点请求伪造攻击的原理,并模拟其攻击过程、解析攻击产生的原因来向读者详细介绍此类攻击的特点,并从服务器端和客户端两个方向讨论了防御此类攻击的策略。     

基于Monte Carlo方法的任意概率密度随机数字信号发生器设计

在信号处理和计算机微观模拟的过程中,经常要构造具有特定概率密度的随机数发生器.采用常规方法实现难度较大且不具普遍性,本文根据Monte Carlo方法基本原理和随机信号的数字特征给出一种任意概率密度随机数发生器的设计方法及核心源代码.实验证明该方法简单高效、通用性好.     

低占空比、低碰撞的异步无线传感器网络MAC协议

提高信道监听质量是降低能量消耗和提高通信效率的有效方法。提出了一种低占空比、低碰撞的PB-MAC(predict-base MAC)协议。通过发送节点精确预测接收节点的唤醒时间,降低占空比;采用基于预测的重建连接机制和数据重传机制,有效地避免碰撞和实现高效重传。OMNet++仿真实验结果表明：在50节点随机网络中,PB-MAC的平均占空比、发送消息耗能和平均碰撞次数分别比RI-MAC少68.60%、24.75%、68.05%,比X-MAC少64.39%、64.05%、70.54%。同时,在网格网络中PB-MAC的性能也优于RI-MAC和X-MAC。     

鱼雷射击随机误差分析的几个问题

借助直航鱼雷直迸射击的描述,研究了射击命中问题的随机误差及其相关性的概念,指出了基于目标运动要素观测值或真值计算成功概率的不同.就客观概率情形,基于误差向量函数的1阶近似或2阶近似研究了计算概率的解析方法,以及关于正态随机向量的一般二次函数分布的均值、方差和特征函数计算公式的一个定理,给出了2阶近似情形计算概率的解析方法,数值实验发现,就直航鱼雷直迸射击成功的客观概率而言,两种方法均有较高精度,且1阶近似方法优于2阶近似方法.     

Elitist Reconstruction Genetic Algorithm Based on Markov Random Field for Magnetic Resonance Image Segmentation

In this paper,elitist reconstruction genetic algorithm(ERGA) based on Markov random field(MRF) is introduced for image segmentation.In this algorithm,a population of possible solutions is maintained at every generation,and for each solution a fitness value is calculated according to a fitness function,which is constructed based on the MRF potential function according to Metropolis function and Bayesian framework.After the improved selection,crossover and mutation,an elitist individual is restructured based on the strategy of restructuring elitist.This procedure is processed to select the location that denotes the largest MRF potential function value in the same location of all individuals.The algorithm is stopped when the change of fitness functions between two sequent generations is less than a specified value.Experiments show that the performance of the hybrid algorithm is better than that of some traditional algorithms.