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.     

灵智的竞争才是美丽的生命——试论石涛的"一画"论

石涛的画论思想实是中国绘画美学的一总结形态,但其在总结的基础上鲜明地提出了绘画乃是出自于“心”的创造,是艺术家主体精神无限拓展的产物,因为只有灵智的竞争才是美丽的生命。     

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。     

内燃机车运行中联合调节器常见故障分析

联合调节器是司机根据机车外界情况变化,调节燃油喷射量,以适应牵引运输要求的一个关键部件,它在使用过程中极易出现故障,电磁连锁、DLS故障及配速系统故障三种现象。通过分析三种故障现象的产生原因,提出一些判断预防和处理的方法。     

天然气汽油两用燃料发动机的发展历程与展望

随着社会的发展与进步,汽车日益普及,对汽油、柴油的消耗大幅增加,机动车尾气排放对环境及能源形势也产生了极大的影响。推进新能源、新技术的研究探索,具有十分重要的现实意义。文章对国内外在天然气/汽油两用燃料发动机方面的技术发展历程进行论述,并分析了天然气/汽油两用发动机的发展与应用趋势。     

内燃机专业实验室的改革与实践

介绍了面向市场确定实验室学术方向、采用与现代工程发展相适应的建设模式、坚持创新实验与生产实际相结合、形成教学科研与社会服务多功能特色的内燃机专业实验室设计思想及其实践效果。     

新疆对外贸易与经济发展相互关系研究

对外贸易是经济增长的“发动机”,许多国家和地区通过时外贸易来推动国家和地区经济发展。新疆对外贸易验证了与经济发展的互动关系,我区应大力发展对外贸易,带动经济增长。     

柴油机的可维修性研究

建立了柴油机具有共性的可维修系统的失效率模型,论述了柴油机的可维修性理论,探讨了其最佳维修周期的界定问题,给出了计算实例。该方法对其他系统的可维修性问题也具有普遍意义。     

化学工业搜索引擎ChemIndustry.com

本文简要介绍了ChemIndustry.com的概况，及其检索方法，以及其与Yahoo、Altaviata和Google的异同。     

Analyzing imbalance among homogeneous index servers in a web search system

The performance of parallel query processing in a cluster of index servers is crucial for modern web search systems. In such a scenario, the response time basically depends on the execution time of the slowest server to generate a partial ranked answer. Previous approaches investigate performance issues in this context using simulation, analytical modeling, experimentation, or a combination of them. Nevertheless, these approaches simply assume balanced execution times among homogeneous servers (by uniformly distributing the document collection among them, for instance)—a scenario that we did not observe in our experimentation. On the contrary, we found that even with a balanced distribution of the document collection among index servers, correlations between the frequency of a term in the query log and the size of its corresponding inverted list lead to imbalances in query execution times at these same servers, because these correlations affect disk caching behavior. Further, the relative sizes of the main memory at each server (with regard to disk space usage) and the number of servers participating in the parallel query processing also affect imbalance of local query execution times. These are relevant findings that have not been reported before and that, we understand, are of interest to the research community.