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针对车间调度问题计算复杂度较高的特点,将协同进化多目标优化算法应用于车间调度问题。计算实例结果表明,协同进化多目标优化算法应用于车间调度问题不仅可以优化效果,而且能够在一定程度上提高计算效率。 相似文献
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电力系统无功优化是一个多变量、多约束的混合非线性规划问题,优化过程十分复杂。带精英策略的快速非支配遗传算法是一种求解多目标优化的优良算法之一。但该算法缺乏明确的约束处理机制。本文在处理约束方法上将约束优化问题转换为多目标问题,将个体支配关系的准则改变为根据不可行解违反约束条件的程度判断哪个更优,保证了种群的多样性和分布陛 相似文献
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社区养老服务点的科学选址对于优化社区养老服务资源配置，促进社区老年人公平、便利获取养老服务具有重要意义。目前服务点的选址仍偏重人工决策，使用科学方法实现社区养老服务点科学布局的研究还十分匮乏。提出一种基于智能优化算法的社区养老服务点选址方法，以最近可及距离为求解目标，以区域内社区数量、老年人数量、最远可及距离、最大服务承载量以及各服务比例配置为约束建立计算模型并求解。根据相应情境，建立不同的目标函数，针对每个目标函数都实施了仿真实验。实验结果表明，提出的优化方法对多约束非线性条件下的社区养老服务点定位均可以找到最优解，为科学解决社区养老资源配置优化问题提供了一种新的思路。 相似文献
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文章研究多无人机协同侦察相控阵雷达模式转移规律过程中的任务分配优化.为了以最小能耗无重复侦察雷达全部波位,根据相控阵雷达波位覆盖方式,分析比较了三种波位侦察点选择方案.在此基础上,根据侦察点访问约束、无人机航程和能耗约束,以无人机总能耗最低为目标,建立多无人机侦察任务分配的多旅行商优化模型.基于单亲遗传—粒子群混合算法(PGA-PSO),使用分组最优个体选择和多变异操作,保证算法快速收敛的同时,提高算法求解精度.仿真结果表明,通过优选侦察点和优化任务分配可大幅提高多无人机协同的侦察效率,改进的PGA-PSO算法较其他算法求解精度高,收敛速度快. 相似文献
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《科技通报》2017,(4)
运用微分代数方程表示涉及代数约束的系统时间域的物理行为是一种表述物理系统行为规律的重要方式。文中复杂物理系统中微分代数方程组的解析方法,选择了分布控制偏微分方程约束下微分代数方程组作为研究对象,利用以局部参数化微分变换法实现方程组多目标优化。首先要将偏微分约束优化问题转变成具有鞍点形式的稀疏线性方程组,为此需要将分布控制微分方程约束化问题进行Galerkin有限元离散,利用先离散后优化的方法获取具备约束优化问题的有限维离散模拟形式;第二,根据一维微分变换法应用在非线性微分代数方程的特性,针对约束系统建立以微分变换法为基础的局部参数化算法,同时将约束系统作为流形上的微分方程组对其完成局部参数化,此操作可有效降低约束流形和方程组的求解难度。仿真实验证明,本文中提出的基于局部参数化微分变换法可以有效地解决微分代数方程组多目标优化问题。 相似文献
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在公平合理利用原则下,从价值取向、影响机制、理想愿景3个方面分析跨境水资源空间均衡分配机理,基于多目标决策理论构建跨境水资源空间均衡分配优化模型。优化模型的目标函数由流域整体效益目标和均衡性目标组成,约束条件包括可用水量限制约束、用水保障约束、公平性约束、尊重历史性约束等。提出了跨境河流可分配水量、流域国需水量两个参数的测算方法,以及求解优化模型的模拟退火算法。针对澜湄流域旱季缺水状况进行实例分析,结果表明：本文得到的优化分配方案,即中国、缅甸、老挝、泰国、柬埔寨、越南6个流域国的分配水量分别为(163.13,21.33,84.17,134.73,68.31,120.33)亿立方米,相对现状用水方案其主要评价指数均明显提升,验证了模型的可行性。 相似文献
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新时期我国商业银行资产负债管理--论自律性资产负债管理策略及组合优化模型 总被引：2，自引：0，他引：2
采用定性与定量相结合的方法，在对商业银行与一般企业的区别及其经营目标分析的基础之上，指出自律性资产负债管理是银行的必然选择，并利用财务管理相关知识和线性规划方法，以资产收益最大化为目标函数，以法律约束、法规约束和经营管理约束为条件，建立了资产负债组合优化决策模型，实现商业银行资产“三性”的平衡，从而有效解决了商业银行各种资产数量的优化配置问题。 相似文献
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将战略协同的概念引入到项目组合选择问题中,定义协同度函数和有序度的概念,分析拟配置项目的环境适应能力和项目间的战略协同关系,以战略目标为序参量构建基于战略协同度的项目组合配置模型,用战略协同发展度来度量协同效应,解决多约束、多关联、多目标的项目组合配置问题;并实例验证了模型的有效性。 相似文献
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【目的】加快构建清洁低碳能源系统和集约高效产业系统是实现经济发展动能转换、形成绿色低碳循环发展经济体系的关键。【方法】本文基于Kaya恒等式构建了产业系统碳排放影响因素模型，以中国30个省份发展规划中政策性目标作为约束条件，利用多目标规划模型对“孤立式”与“协同式”两种优化策略下省际能源结构、产业结构、碳排放量等特征进行分析。【结果】研究发现：(1)在当前能源与产业结构下，经济增长与节能减排目标难以兼顾，“协同式”优化策略下中国二氧化碳潜在减排规模更大，为78082.90万t。(2)能源强度是现阶段影响碳排放的主导因素，省际产业能源协同的碳排放效应具有两面性，应重视碳排放随产业发生转移的问题。(3)在充分实现能源调配和产业转移的情况下，东中西部总产值平均增长幅度为7.98%，经济结构显著优化，地区特色更为突显，一定程度上打破了地区间产业同构的窘境。【结论】本文通过对多重目标约束下地区差异化发展策略的碳排放效应进行探讨，证实了多重目标约束下省际“协同式”策略的碳减排效应更为显著，为构建中国绿色低碳循环发展经济体系提供方法借鉴和政策启示。 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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《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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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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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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《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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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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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