一种改进的一致性扩散图像增强方法

一致性扩散是分析图像中定向结构的重要的预处理步骤,现有的一致性扩散图像增强方法难以识别图像中的弱边界。本文提出了一种改进的扩散方法,该方法构建了一种结合二阶方向导数信息的结构张量,能够精确分析图像中的复杂弱边界,同时与经典结构张量互为补充以检测图像的强边界。在此基础上设计了新的扩散张量,并采用了基于(加性分裂算子AOS)策略的数值计算方法。通过对比实验证明,该文算法的效果良好并具有很高的效率, 实现了在去除噪声的同时精确保护图像中的强弱边界。     

教育电视数字DV视频制作平台构建

随着数字技术的发展,电视节目制作已进入了数字化时代.高校教育电视因资金限制,电视制作设备一直处于陈旧、档次低、老化等状态,DV数字视频制作产品的出现,以其性能优良、经济实用、方便快捷等优势成为教育电视数字化进程的首选设备.介绍常用数字便携DV摄像产品及非线性编辑产品的性能和高校教育电视数字视频构建的平台方案.     

Survey on computation offloading in mobile edge computing

Computation offloading in mobile edge computing would transfer the resource intensive computational tasks to the edge network.It can not only solve the shortage of mobile user equipment in resource storage,computation performance and energy efficiency,but also deal with the problem of resource occupation,high latency and network load compared to cloud computing.Firstly the architecture of MEC was introduce and a comparative analysis was made according to various deployment schemes.Then the key technologies of computation offloading was studied from three aspects of decision on computation offloading,allocation of computing resource within MEC and system implement of MEC.Based on the analysis of MEC deployment scheme in 5G,two optimization schemes on computation offloading was proposed in 5G MEC.Finally,the current challenges in the mobility management was summarized,interference management and security of computation offloading in MEC.     

Performance evaluation of random power capture on mobile communications

Power assignment schemes are man‐made methods to enhance the capture effect of radio communications. In a previous study, Wen and Yang investigated the combined capture effect of the fixed power assignment scheme, Rayleigh fading, and near–far effect on the performance of packet radios. The performance analysis was limited to an infinite population environment. This assumption is reasonable for a conventional packet radio system with a vast service area. However, for a cellular mobile system, a finite population model should be used. In this paper, we analyse the combined natural and man‐made capture effect on the performance of a cellular system with finite population in each cell. A random power assignment scheme is adopted to produce the man‐made capture. The system throughput and delay are carried out by a Markov model. Some numerical calculations are used to demonstrate the degree of performance improvement. Copyright © 2001 John Wiley & Sons, Ltd.     

分组丢弃算法性能仿真研究

该文研究了在固定有效带宽、时变有效带宽情况下和不同种业务环境下,EPD(EarlyPacketDiscard)和PPD(Partial Packet Discard)算法的通过率和公平性,认为采用EPD算法的ATM交换机,靠近该交换机的业务源可以得到更高的通过率。而远离该交换机的业务源的通过率较低。该文的研究进一步得到了解决这种不公平性的一种实用方案。     

基于中国剩余定理的门限RSA签名方案的改进

针对基于中国剩余定理的门限RSA签名方案无法签署某些消息,以及部分签名合成阶段运算量大的问题,论文提出一种基于虚拟群成员的改进方法,使得改进后的方案能够签署所有消息,同时能够极大地减少部分签名合成阶段的运算量,当门限值为10时,可以将部分签名合成阶段的运算量减少为原来的1/6。对改进方案进行了详细的安全性和实用性分析。结果表明,改进方案在适应性选择消息攻击下是不可伪造的,且其运算效率较其他门限RSA签名方案更高。     

不同地形条件下架空配电线路防雷方案研究

作为供电系统当中的电能分配的关键设备,架空配电线路的安全与稳定直接影响着整个供电系统的正常运行。雷电灾害是架空配电线路当中频繁遇到的一种自然灾害,因此线路的防雷工作十分重要。本文在对架空配电线路的引雷范围、雷击跳闸率计算的分析基础上,探讨其在不同地形条件下的防雷方案。     

Capacity of SSTS for downlink‐distributed antenna systems in multicell environment

We put forward a novel single selection transmission scheme based on maximum desired signal criterion and investigate the capacity of distributed antenna systems in multicell environment. However, for most of the recent literatures, the interference plus noise is treated as Gaussian random variable with fixed variance by the central limit theorem, which ignores the effect of the short‐term fading on interference. To avoid it, non‐central limit theorem is adopted in which the variance of interference plus noise is considered as a random variable with changeable variance influenced by the short‐term fading. Moreover, channels are assumed to suffer from independent identical Rayleigh fading together with propagation path loss, and the closed‐form expression of capacity for distributed antenna systems is derived. Finally, extensive simulations are carried out to validate the theoretical analysis. Copyright © 2015 John Wiley & Sons, Ltd.     

德兴铜矿4#尾矿库1#斜槽冒尾砂治理研究

针对德兴铜矿１＾＃斜槽严重的冒尾砂状况,进行了冒尾砂原因分析,并采用声波探测等技术手段,应用概率极限状态法,有限元和结构可靠的分析方法对１＾＃斜槽进行了安全分析,并提出了相应的工程治理方案。     

基于因数分解和离散对数的数字签名协议

本文设计了两个数字签名协议,它们的安全性基于因数分解和离散对数的困难性,它们的性能类似于基本的ElGamal数字签名协议和Harn数字签名协议。本文还讨论了几种可能的攻击,证明了它们的安全性高于后两种数字签名协议。