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《科技通报》2016,(6)
基于智能仿生计算的蚁群优化算法在路径规划问题中具有较好的应用前景,通过蚁群算法优化,实现机器人路径规划和应急救援的路径规划等。传统的基于蚁群算法的路径规划在信息素转换中容易导致信息丢失,产生局部收敛,提出一种基于信息素多目标Pareto支配的蚁群优化算法实现路径规划,利用信息素多目标Pareto集合序列的均匀遍历特性和逻辑差分变尺度特征,进行变尺度搜索,根据蚁群优化算法一次次地更新搜索空间,结合负反馈机制,通过蚂蚁的信息素转化进行路径分析,采用Pareto支配集记录下最优的食物源,蚁群在寻找食物过程中,避免了局部寻优和局部收敛,仿真结果表明,采用该算法进行蚁群优化后的路径规划避障效果较好,以较快的收敛速度和较少的迭代次数找到最优路径,收敛性好。 相似文献
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针对传统的蚁群算法设计机器人避障路径规划,自适应能力差,全局优化能力和搜索速度不好的问题,在传统算法的基础上,提出一种采用奖惩规则格栅建模的机器人避障规划算法。提出构建模型主体的行为规则和避障规则,通过在栅格环境中设置量子遗传进化的多个有效的行为规则,设计了信息素更新的奖惩规则,修改其路径上的信息素,改变量子本身携带的信息素,得到优化避障最小距离。最终获得了复杂环境下的最优路径。仿真实验表明采用该算法进行机器人避障路径规划,在未知复杂环境下能够快速地规划出安全的优化路径,机器人避障路径规划具有很好的自适应性,相比传统的蚁群算法,其全局优化能力和搜索速度都得到了显著提高。 相似文献
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视网膜下积液的容积计算可以被用来评价不同类型的视网膜和黄斑紊乱,因此准确找到下积液的轮廓也就十分必要。但是,目前关于视网膜下积液边界分割的研究很少。本文的目的是根据图像的灰度和梯度特征来分割出视网膜下积液,该方法利用图论分割算法找到经常出现下积液的区域边界,限定搜索区域后利用自适应阈值和梯度阈值来达到分割的目的。实验表明,该方法对于分割视网膜下积液效果良好。 相似文献
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蚁群算法是通过模拟蚂蚁觅食而发展出的一种新的启发式算法但是开始的时候信息素缺乏,收敛速度慢一直是蚁群算法的不足。针对该问题,提出加权蚁群算法,它利用传统蚁群算法最优路径的特点,对每个城市分别加权,然后从比较离散的点开始进行寻优。节省了在不可能构成最优路径上的计算时间,提高了运算速度。计算机仿真结果表明,该文算法改进了标准蚁群算法的效率和计算结果的质量。 相似文献
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研究了云计算环境下的任务调度问题,通过构造云计算环境下的任务调度模型,提出了一种混合调度算法,该算法是蚁群算法与遗传算法的有机融合。其中的遗传算法采用间接编码方式,结合由遗传算法衍生出的优化解,对蚁群信息素的分布进行初始化处理,使遗传算法的快速搜索能力得到充分利用,并通过克服蚁群算法的起始信息素不足问题,加快了求解速度。云计算环境下的仿真实验结果表明,该混合算法是一种行之有效的任务调度算法。 相似文献
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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
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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
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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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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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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
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《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
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《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
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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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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