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MIMO多跳无线网络 总被引:1,自引:0,他引:1
综述了多跳无线网络MIMO(multiple-input multiple-output)技术的研究进展,分析了MIMO技术的引入对多跳无线网络各层及整体设计的影响.以跨层协议设计为重点,详细介绍了当前典型的基于MIMO的多跳无线网络协议算法的核心机制,并比较分析了这些算法的特点和性能差异与存在的缺陷.最后,结合本领域内的研究现状,指出了基于MIMO的多跳无线网络走向实际工程应用环境所亟待解决的关键问题,指出了基于MIMO技术设计自适应调整、高性能多跳无线网络跨层模型及协议的重要性. 相似文献
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在移动边缘计算中通过将终端设备的计算任务卸载到边缘服务器,可以利用边缘服务器资源解决终端设备计算能力不足的问题,同时满足移动应用程序对低延迟的需求.因此,计算卸载备受关注并成为移动边缘计算的关键技术之一.本文对移动边缘计算的计算卸载研究进展进行深度调研.首先,总结归纳出两类计算卸载方法——基于启发式算法的传统方法和基于在线学习的智能方法;从最小化延迟时间、最小化能耗、权衡时间和能耗三个不同优化目标对基于启发式算法的传统计算卸载进行分析对比;梳理了基于在线学习智能计算卸载采用的底层人工智能技术;然后介绍了边缘服务器资源分配方案和新兴的移动边缘计算应用场景;最后分析计算卸载方案存在的问题并展望移动边缘计算的计算卸载研究的未来方向,为后续研究工作指明方向. 相似文献
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Yi-Lin Fang Zhi-Lin Wu Meng-Wu Xiao Yu-Ting Tang Kang-Ming Li Jiao Ye Jian-Nan Xiang Ai-Xi Hu 《International journal of molecular sciences》2016,17(5)
With the aim of discovering new anticancer agents, we have designed and synthesized novel α-aminophosphonate derivatives containing a 2-oxoquinoline structure using a convenient one-pot three-component method. The newly synthesized compounds were evaluated for antitumor activities against the A549 (human lung adenocarcinoma cell), HeLa (human cervical carcinoma cell), MCF-7 (human breast cancer cell), and U2OS (human osteosarcoma cell) cancer cell lines in vitro, employing a standard 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The results of pharmacological screening indicated that many compounds exhibited moderate to high levels of antitumor activities against the tested cancer cell lines and that most compounds showed more potent inhibitory activities comparable to 5-fluorouracil (5-FU) which was used as a positive control. The mechanism of representative compound 4u (diethyl((2-oxo-1,2-dihydroquinolin-3-yl)(phenyl-amino)methyl)phosphonate) indicated that the compound mainly arrested HeLa cells in S and G2 stages and was accompanied by apoptosis in HeLa cells. This action was confirmed by acridine orange/ethidium bromide staining, Hoechst 33342 staining, and flow cytometry. 相似文献
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超节点P2P(Super-peerP2P)结合了P2P结构和C/S结构的优点,是当前应用最广的一类P2P系统。在超节点P2P网络中,文件访问是最基本的操作,往往使用缓存技术来提高其操作效率。目前大多数超节点P2P网络使用传统的“尽力而为”的缓存机制,该机制没有区分超节点网络中不同节点对资源的需求及关注程度不同,导致偶尔访问的对象替换经常访问的对象。针对“尽力而为”缓存机制的不足,本文提出一种基于语义信息的协同缓存管理机制SCOCM(Semantic-based Cooperative Cache Management mechanism for super-peer net works),应用已经请求对象的语义信息主动地选择对象放置缓存,以兴趣度的远近驱逐缓存内的对象,减少缓存对象的替换,使得每个缓存中缓存的对象之间尽可能地保持语义联系。实验结果表明,基于语义信息的协同缓存管理机制与LRU相比可大大降低缓存的替换率,提高缓存的存取效率,命中率也较高。 相似文献
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The design problem of state variance constrained control for stochastic systems has received rather extensive attention in recent years. This paper solves the state variance constrained controller design problem by using the covariance control theory, with observed-state feedback gains for continuous Takagi-Sugeno (TS) fuzzy models. By incorporating the technique of state estimation into the practical covariance control theory, a variance constrained control methodology is developed for the continuous TS fuzzy models. Finally, a numerical example is shown to demonstrate the efficiency and applicability of the proposed approach. 相似文献
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Dong-Ya Sun Bi-Zhou Lin Bai-Huan Xu Li-Wen He Cong Ding Yi-Lin Chen 《Journal of Porous Materials》2008,15(3):245-251
Layered composites, Zr-intercalated MoS2, have been prepared utilizing the exfoliation and restacking properties of Li x MoS2 under mild conditions and characterized by X-ray powder diffraction, differential scanning calorimetry and BET surface measurements. It showed the formation of two distinct products depending on the employed Zr:MoS2 reaction stoichiometry. The interlayer expansions of about 4.4 Å and 9.2 Å suggested mono- or bi-layer arrangements of the hydroxyl–Zr oligocations into the interlayer galleries between the MoS2 host layers. The composites exhibit good catalytic activities in the hydrogenation of nitrobenzene into aniline, due to their intercalated structures and great specific surface areas. 相似文献
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煤矿企业既是产能大户又是耗能大户,节能降耗已成为煤矿企业增收节支的重要指标,许多煤矿企业都非常重视高耗能用电设备的节能改造工作。通风设备是煤矿的主要耗能设备之一,本文以平煤八矿主通风机节能改造为例,对矿井通风机实施变频改造的必要性,变频改造系统的设计,改造后的经济效益进行了分析。论证了高压变频器的应用于煤矿主扇风机的系统改造,必将取得良好的运行效果和经济效益。 相似文献
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遗传算法用于结晶过程动力学参数辩识 总被引:7,自引:1,他引:6
遗传算法是一类随机优化方法。常被用于解决复杂的优化问题,基于群体的搜索,重组和变异是遗传算法区别于其他优化方法的主要特征。文章中将遗传算法应用于过饱和溶液Li2O.3B2O3-H2O体系结晶过程动力学参数辨识,确定了结晶反应速率常数、热力学平衡浓度和表观反应级数。 相似文献
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