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1.
TSP问题是典型的NP难组合优化问题,而遗传算法是求解此类问题的一种方法。但遗传算法存在收敛速度慢和陷入局部最优的问题。针对上述问题并结合TSP的特点提出了一种改进的遗传算法,对传统遗传算法的各种操作与算子进行了优化与改进,较好地解决了种群多样性与算法收敛性的矛盾。实验结果表明,改进后的算法明显优于传统遗传算法,说明该算法具有良好的有效性与可行性。 相似文献
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分析了遗传算法和模拟算法的主要优缺点,提出一种用于求解旅行商问题（TSP）的改进遗传算法,该算法有效地将遗传算法和模拟退火算法相结合,在很大程度上缩短了算法的搜索时间;利用MATLAB对多种TSP问题进行仿真研究,实验结果证明了改进的遗传算法的有效性。 相似文献
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TSP问题作为NP难题的典型代表,计算机算法理论研究的热点,各种针对该问题的算法层出不穷。对近期出现的面向TSP问题的免疫遗传算法进行了介绍与总结,在分析了算法特点之后,提出了算法的改进方向,对TSP问题的研究进行了展望。 相似文献
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两段式遗传算法求解CTSP 总被引：1，自引：0，他引：1
旅行商问题（TSP）是一类典型的NP完全问题,遗传算法（GA）是求解这类问题的常用方法之一。针对中国旅行商问题（CTSP）,设计了两阶段遗传算法的改进策略。第一阶段在SGA基础上采取控制参数优化和保优操作,求得若干个较优解;第二阶段采用变异操作,在第一阶段较优解组成的种群基础上寻找最优解。用该策略迅速找到了CTSP最优解,该路径长度为15378km,比目前已知CTSP解更优。对遗传算法迅速求解TSP最优解提供了可行解决方案。 相似文献
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TSP问题是一个典型的NP完全问题。近年来,学者们尝试用多种算法来解决TSP产生的“组合爆炸”问题。其中,遗传算法因为其自身的优点,逐渐成为解决TSP问题的有效手段之一。在对TSP问题和遗传算法充分描述的基础上,利用遗传算法模拟TSP问题,并给出了计算机实现过程以及实验结果。 相似文献
6.
一种改进的并行混合遗传算法在求解TSP问题中的应用 总被引：1，自引：0，他引：1
遗传算法(GeneticAlgorithm,GA)是一种基于自然群体遗传机制的有效搜索算法。由于它在搜索空间中同时考虑许多点,这样就减少了收敛于局部极小的可能,也增加了处理的并行性。因此,可以利用并行遗传算法(PGA)研究典型的组合优化实例-TSP问题(旅行商问题)的求解问题,提出一种改进的主从式并行混合遗传算法求解TSP问题。实验结果表明,该方法在解的精度和速度上优于以前的算法。 相似文献
7.
蚁群算法是通过模拟蚂蚁觅食而发展出的一种新的启发算法.基于群体的协作与学习,该算法已经成功地解决诸如TSP问题等多种组合优化问题.本文提出了一种改进蚁群算法.该算法根据人工蚂蚁所获得解的情况,应用一种选择策略,从而使得算法跳离局部最优解,并采用局部搜索,以获得更好的优化解.通过仿真实验获得的结果表明,该算法对于蚁群算法具有较好的改进效果. 相似文献
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针对远航程无人水下航行器的路径规划问题,本文提出了一种基于旅行商(TSP)问题的路径规划的新方法。阐述了TSP问题的基本原理,并采用了模拟退火算法和遗传算法进行了仿真研究,获得较好的仿真结果。 相似文献
11.
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
12.
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
13.
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
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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
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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
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献
19.
Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese 相似文献
20.
WANG Sijia 《中国科学院院刊(英文版)》2014,(2):192-194
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages. 相似文献