Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.     

塞曼效应实验的数字化信息处理

通过引进数码相机、计算机设备,使复杂塞曼效应实验中的光学信号转化成数字化信息进行处理,不仅大大提高实验准确度和效率,且通过学生对测试软件的设计和使用,达到培养学生创新能力的目的。     

武清地热热储数值模拟

采用 AU TOU GH2热储计算软件对天津市武清县地热热储进行数值模拟计算 ,分析热储在不同开发利用条件下的特征 .主要针对无回灌和有回灌两种生产情况 ,分析地热热储的温度、压力随时间和距离的变化 ,还分析随地热水的生产 ,地热热储的生产能力、水位和压力的变化以及回灌对生产井的冷却效应     

刚性常微分方程的数值解法在化学动力学中的应用

解刚性常微分方程已成为复杂化学反应研究的重要途径，本介绍了化学动力学计算中的刚性问题和数值解法，并着重讨论常用的吉尔(Gear)法和半隐式龙格库塔(Semi-implicit Runge-Kutta)法及其在化学动力学中的应用。     

基于电子商务的精确搜索引擎的研究与实现

随着科技的发展,电子商务日益活跃。现行的电子商务打折网站与生俱来的局限性,越来越跟不上时代的步伐。能否开发一个能够收集全球打折信息的电子商务网站,越来越引起人们的重视。采用精确搜索引擎算法的电子商务精确搜索引擎模型,具有很好的精确性和响应速度,能够查询到精确而全面的打折信息,有较高的实用价值。     

单板剪切机数控系统的设计

根据木工单板剪切机工作的特点,研制了一种基于旋转编码器和单片机控制的单板剪切机数控系统,主要由绝对位置测量系统、单片机控制系统、剪切系统和单板夹持系统四部分组成,可以通过设置剪切参数,方便调节剪切长度,最大程度避免浪费,提高工效.     

《机床数控原理与系统》课程教学改革探讨

《机床数控原理与系统》是数控技术专业的一门核心课程,其课程教学质量将直接影响着学生今后的岗位实践技能和知识的内化、迁移、发展能力。文章将就如何提高课程的教学质量,从课程内容、教学体系、教学组织、教学方法、教学手段等方面进行探讨。     

均匀带电薄圆盘和薄宽圆环静电势的数值研究

用叠加原理和数值积分法,分别对均匀带电薄圆盘和薄宽圆环的静电势进行数值研究.绘制了电势的空间分布图及其等势线图.     

FARMER: A novel approach to file access correlation mining and evaluation reference model

File semantic has proven effective in optimizing large scale distributed file system. As a consequence of the elaborate and rich I/O interfaces between upper layer applications and file systems, file system can provide useful and insightful information about semantic. Hence, file semantic mining has become an increasingly important practice in both engineering and research community. Unfortunately, it is a challenge to exploit file semantic knowledge because a variety of factors could affect this information exploration process. Even worse, the challenges are exacerbated due to the intricate interdependency between these factors, and make it difficult to fully exploit the potentially important correlation among various semantic knowledges. This article proposes a file access correlation miming and evaluation reference (FARMER) model, where file is treated as a multivariate vector space, and each item within the vector corresponds a separate factor of the given file. The selection of factor depends on the application, examples of factors are file path, creator and executing program. If one particular factor occurs in both files, its value is non-zero. It is clear that the extent of inter-file relationships can be measured based on the likeness of their factor values in the semantic vectors. Benefit from this model, FARMER represents files as structured vectors of identifiers, and basic vector operations can be leveraged to quantify file correlation between two file vectors. FARMER model leverages linear regression model to estimate the strength of the relationship between file correlation and a set of influencing factors so that the “bad knowledge” can be filtered out. To demonstrate the ability of new FARMER model, FARMER is incorporated into a real large-scale object-based storage system as a case study to dynamically infer file correlations. In addition FARMER-enabled optimize service for metadata prefetching algorithm and object data layout algorithm is implemented. Experimental results show that is FARMER-enabled prefetching algorithm is shown to reduce the metadata operations latency by approximately 30%–40% when compared to a state-of-the-art metadata prefetching algorithm and a commonly used replacement policy.     

基于遗传算法的高校试题组卷系统的研究

阐述了高校组卷系统的原理,重点研究了作为系统关键的组卷策略运算过程,提出了一个改进的动态分层遗传算法作为高校组卷系统的组卷策略,最后通过实验检验其性能。