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1.
考虑电磁环境约束建立无人机航迹规划模型,采用多目标模拟退火优化算法完成航迹规划。经仿真验证,该算法可有效完成航迹规划,实现无人机飞行过程中电磁环境最优、航路最短等多目标优化。 相似文献
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《科技通报》2015,(12)
研究云计算环境下的大型智能交通调度问题。云计算环境下的大型智能交通网络在进行车辆调度的过程中,由于运算量过于庞大,造成交通调度效率降低,运输成本增加。利用传统的遗传算法进行交通调度的过程中,无法避免由于早熟和停滞的现象造成的影响,难以搜索到最优交通路线,从而降低了交通调度的效率。为此,提出一种基于神经网络算法的大型智能交通调度方法,根据约束条件建立神经网络模型,确定各神经层中神经元的输入与输出关系式,从而得到基于神经网络算法的最优交通调度方案。实验结果表明,利用改进算法进行云计算环境下的大型智能交通调度,缩短了交通调度完成时间,提高了交通调度效率,效果令人满意。 相似文献
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云计算服务器的环境不同,一旦出现网络资源拥塞,各区域采用的网络资源调度形式也不同。当前单一的网络资源调度方式很难满足云计算网络复杂性的要求。提出一种基于需求和供给均衡机制的云计算网络规划模型,采用二次加权平均方法构建云计算时效网络规划模型,模型不断调整已分配到路段上的网络资源数量,采用AGV控制网络堵塞评估问题,分析云计算网络设备需求的确定和供需平衡机制,面向节点数、成本以及拥塞程度三个因素明确云计算网络拥塞强度的评估指标体系,确定资源配送的时限要求和紧迫程度。实验结果说明,该种模型下的云计算拥塞救助效率、成本以及效用度都优于传统模型,具有较高的应用价值。 相似文献
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研究在云平台环境下的网络交互数据优化加密技术以提高云计算服务器的响应效率,降低服务器响应时间。传统方法采用行为子网络动态密钥构造模型实现云计算循环加密,无法有效满足用户在Possion分布下服务器响应效率。提出一种基于云计算循环加密的服务器响应效率优化算法。构建云平台环境下的网络数据交互模型,采用云计算速度调节动态优化技术提高服务器的响应效率,采用码元频数检测的加密和解密方案,构建云平台环境下的数据交互节点拓扑模型,根据节点剩余度规则,得到后代节点失效过载比,通过部分链路失效多路径加密方法使得数据聚集具有很高的容错功能,进而提高服务器响应效率。仿真实验表明,算法具有较好的数据加密准确性,该方法能有效缩短云计算服务器响应时间。 相似文献
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为了解决同构多核心处理器任务调度中空调度、无用调度过多,效率较低的问题.提出一种基于反馈约束神经网络的同构多核心处理器任务调度算法.以处理器调度任务完成时间最短为优化目标,建立一个反馈约束的处理器任务调度数学模型,然后采用神经网络算法对其进行求解,并通过有效的约束机制保障计算结果陷入局部最小.计算机仿真测试表明,约束神经网络算法可以获得的同构多核心处理器多任务调度的最优方案,具有一定应用价值. 相似文献
6.
多媒体服务器的混合协议设计与实现的关键在与设计混合协议激振算法,通过激振算法设计提高多媒体混合服务器在饱和状态下的吞吐量。传统方法采用动态时分多址协议进行混合协议激振设计,当系统中节点众多、网络拓扑易变状态下,服务器的吞吐性能不好,提出一种基于CDMA协同调度的混合协议激振算法,并设计多媒体服务器,将大型多媒体联合服务器网络接收端和发送端数据的信息熵作为信道传递向量函数,在成功完成调度后,从节点开始进行正常收发工作,实现对时分多址(E-TDMA)协议设计。通过CDMA协同调度,在多媒体混合服务器的每一维度进行数据集分割,得到激振冲击响应。进行多媒体服务器总体模型构建与网络模型设计,在MAC层分别采用,三种协议进行系统调度和多媒体服务器的激振设计与仿真实现。仿真结果表明,该模型能有效提高多媒体服务器的吞吐性能,多媒体信道传输时间消耗最短,体现了算法较好的稳定性和鲁棒性能,对多媒体信息传输的保真性较好。 相似文献
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作为项目调度管理中三大控制要素的工期、成本、质量是决定项目建设成败的关键。首先通过采用动态加权技术构建工期-成本-质量的多目标综合优化模型,同时鉴于基本粒子群算法容易陷入局部最优,提出一种将混沌优化嵌入基本粒子群的新算法用于求解该多目标项目调度模型问题。最终通过实例计算表明:相对于基本的粒子群算法,混沌粒子群算法可以更为准确快速地解决该模型下的工程项目多目标优化问题,实现了项目调度管理中有效平衡工期-成本-质量各目标,并达到综合最优方案的理想效果。 相似文献
10.
《科技通报》2016,(8)
恐袭威胁具有突发性和非规律性的特点,且通常发生在人群聚集区,增大了该区域交通调度的难度,传统的调度方法主要针对静态场景进行调度,在发生恐袭威胁时,不能兼顾车辆调度的效率及能耗问题,调度消耗过大,不能满足实际的调度需求。提出基于禁忌搜索算法与遗传算法相融合的恐袭威胁下的最优交通调度方法。以恐袭威胁区域交通调度距离最小、能耗最小、时间最短为目标,建立相应的交通调度模型,采用禁忌搜索算法与遗传算法相融合的调度方法,对模型进行最优解搜索,获取最优调度方案,实现基于大数据分析的恐袭威胁下的最优交通调度。实验结果表明,采用改进算法进行恐袭威胁下的交通调度能够有效的推算出车流,提高调度效率、降低分析成本,具有极高的应用价值。 相似文献
11.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
12.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
13.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
15.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
17.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献