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求解多车场累积时间车辆路径问题的Memetic算法
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作者 刘竹馨 许维胜 曾正洋 《机电一体化》 2014年第A02期9-12,55,共5页
在应急救援车辆路径优化问题中,为了及时救援,缩短所有受灾点的总等待时间,提出了多车辆车场累积时间车辆路径问题。它是多个车场通过多个运输车队,使所有受灾点等待时间总和最短的运输问题。针对该NP难问题提出了一种Memetic算法求解... 在应急救援车辆路径优化问题中,为了及时救援,缩短所有受灾点的总等待时间,提出了多车辆车场累积时间车辆路径问题。它是多个车场通过多个运输车队,使所有受灾点等待时间总和最短的运输问题。针对该NP难问题提出了一种Memetic算法求解。先用改进的最优切割算法MDVRP-Split将受灾点分配至各车场,通过选择、交叉及局部搜索得到最优路径。标准算例的测试结果表明,提出的算法注重了求解质量与求解效率的平衡。 展开更多
关键词 多车场累积时间车辆路径问题 MEMETIC算法 最优切割 局部搜索
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后发企业技术能力提升路径及其微观机理研究 被引量:4
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作者 蒋再文 王涛 江积海 《华东经济管理》 CSSCI 2011年第7期80-84,共5页
技术能力是企业竞争优势的重要源泉,而后发企业与领先企业的技术活动、技术能力累积和技术发展路径存在本质的区别。文章首先根据各种文献,比较后发企业与后进、领先企业等概念,明确后发企业的内涵,指出后发企业与领先企业在技术能力累... 技术能力是企业竞争优势的重要源泉,而后发企业与领先企业的技术活动、技术能力累积和技术发展路径存在本质的区别。文章首先根据各种文献,比较后发企业与后进、领先企业等概念,明确后发企业的内涵,指出后发企业与领先企业在技术能力累积路径的差异性。同时,综述了后发企业实现追赶的主要理论解释。然后分析后发企业技术学习和能力累积的几个重要模型,重点探讨两个典型的技术能力累积路径,以及影响技术学习过程的关键动因。最后,归纳了韩国汽车、半导体、钢铁等产业内的后发企业实现跨越式成长的经验。 展开更多
关键词 后发企业 技术学习 技术能力 累积路径
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无线自组网中一种高效的路由协议 被引量:2
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作者 焦贤龙 王晓东 周兴铭 《计算机科学与探索》 CSCD 2008年第5期478-486,共9页
无线自组网与传统的有线网不同,它由一些可移动的结点组成,这些结点的带宽、计算能力和能量都受到一定限制。针对这种网络,研究者们提出了按需路由协议,这些协议非常适合无线自组网这种拓扑结构,但是由于缺乏对全局拓扑和结点移动性的了... 无线自组网与传统的有线网不同,它由一些可移动的结点组成,这些结点的带宽、计算能力和能量都受到一定限制。针对这种网络,研究者们提出了按需路由协议,这些协议非常适合无线自组网这种拓扑结构,但是由于缺乏对全局拓扑和结点移动性的了解,可能达不到最优。因此提出了一种高效的路由协议ERNC,该协议基于已提出的SHORT路由协议[13],并对以前所提出的NAOR协议[14]进行了扩展,即利用网络编码技术来进一步提高路由协议的性能。最后,使用NS-2模拟器来评估ERNC的性能,结果显示ERNC在分组投递率和平均端到端时延等方面获得了比已有协议更好的性能。 展开更多
关键词 路由 路径累积 网络编码 无线自组网
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考虑零部件制造误差的精密主轴几何回转精度计算方法 被引量:13
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作者 孙岩辉 洪军 +1 位作者 刘志刚 郭俊康 《机械工程学报》 EI CAS CSCD 北大核心 2017年第3期173-182,共10页
提出一种通过精密主轴的结构及零部件制造误差预测其几何回转精度的计算方法。首先利用零部件之间的约束定位关系建立精密主轴的有向图模型,以此筛选出误差累积路径及关键公差;进而使用小位移旋量对各关键公差建模,通过齐次坐标变换的... 提出一种通过精密主轴的结构及零部件制造误差预测其几何回转精度的计算方法。首先利用零部件之间的约束定位关系建立精密主轴的有向图模型,以此筛选出误差累积路径及关键公差;进而使用小位移旋量对各关键公差建模,通过齐次坐标变换的方法分析了4种主轴零件之间典型配合的误差传递过程;再将误差累积路径上的关键公差联系起来,得到主轴几何回转误差分析模型;在此基础上,结合蒙特卡洛模拟仿真方法,统计分析得到主轴几何回转精度的变动范围,得到其公差值;继而通过灵敏度分析,获得对各零件公差对回转精度的贡献度大小,为公差设计结果的改进提供依据。结果表明,该方法可以有效预测精密主轴的几何回转精度以及各零件公差对其影响程度。 展开更多
关键词 有向图 累积路径 关键公差 误差传递 几何回转精度
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共同富裕背景下农村老年人健康风险产生机制追溯分析 被引量:4
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作者 李芬 高向东 《兰州学刊》 CSSCI 2022年第9期135-147,共13页
追溯农村老年人健康风险的产生根源,对提高农村老年人健康水平和扎实推进共同富裕有着重要的现实意义。农村老年人健康风险受早期不良事件的影响,早期经历不良事件数量越多、持续时间越长,老年期健康风险的累积效应越显著;而早期单一不... 追溯农村老年人健康风险的产生根源,对提高农村老年人健康水平和扎实推进共同富裕有着重要的现实意义。农村老年人健康风险受早期不良事件的影响,早期经历不良事件数量越多、持续时间越长,老年期健康风险的累积效应越显著;而早期单一不良经历的健康劣势累积效果相对较弱。早期健康风险劣势累积效应可通过中介变量表现出显著的时间累积效应。控制早期健康风险,有助于以健康预防理念推动人口健康素质提升,推进农村共同富裕。 展开更多
关键词 健康风险 农村老年人 共同富裕 累积路径
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Comparative Studies on Uptake Pathway of Cadmium by Perna viridis 被引量:4
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作者 FANG Zhanqiang 《Journal of Ocean University of China》 SCIE CAS 2006年第1期49-54,共6页
Experiments were designed to expose the filter-feeding bivalve Perna viridis to different Cd-contaminated water environments in order to compare the different pathways through which Cd is accumulated. Results show tha... Experiments were designed to expose the filter-feeding bivalve Perna viridis to different Cd-contaminated water environments in order to compare the different pathways through which Cd is accumulated. Results show that mussels can accumulate Cd through seawater, food, sediment and suspended particle pathways in a short period of time. Mussels' uptake of Cd through the seawater pathway reaches the highest concentration approximately 3 and 9 times larger than through the algae and sediment pathways respectively after 7 d. This indicates that the Cd-accumulation through seawater is most efficient. Results also indicate that the uptake directly through contaminated algae, particles or sediments ingested by mussels is less important when compared with the uptake of Cd by mussels through the seawater pathway. Metal uptake pathways and mechanisms of bioaccumulation by marine bivalve are also discussed in this paper. 展开更多
关键词 uptake pathway BIOACCUMULATION CADMIUM Perna viridis
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Cumulative prospect theory-based user equilibrium model with stochastic perception errors 被引量:1
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作者 WANG Wei SUN Hui-jun 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2465-2474,共10页
The cumulative prospect theory(CPT) is applied to study travelers' route choice behavior in a degradable transport network. A cumulative prospect theory-based user equilibrium(CPT-UE) model considering stochastic ... The cumulative prospect theory(CPT) is applied to study travelers' route choice behavior in a degradable transport network. A cumulative prospect theory-based user equilibrium(CPT-UE) model considering stochastic perception error(SPE) within travelers' route choice decision process is developed. The SPE is conditionally dependent on the actual travel time distribution, which is different from the deterministic perception error used in the traditional logit-based stochastic user equilibrium. The CPT-UE model is formulated as a variational inequality problem and solved by a heuristic solution algorithm. Numerical examples are provided to illustrate the application of the proposed model and efficiency of the solution algorithm. The effects of SPE on the reference point determination, cumulative prospect value estimation, route choice decision and network performance evaluation are investigated. 展开更多
关键词 cumulative prospect theory user equilibrium stochastic perception error variational inequality
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Fatigue damage rule of LY12CZ aluminium alloy under sequential biaxial loading 被引量:2
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作者 WANG YingYu ZHANG DaChuan YAO WeiXing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第1期98-103,共6页
A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ alumin- ium alloy. The loading paths of 90° out-of-phase, 45° out-of-phase and 45° in-p... A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ alumin- ium alloy. The loading paths of 90° out-of-phase, 45° out-of-phase and 45° in-phase are utilized. The fatigue damage cumulative rules under two-level step loading of three loading paths are analyzed. By introducing a parameter a which is a function of the phase lag angle between the axial and the torsional loading, a new multiaxial nonlinear fatigue damage cumulative model is proposed. The proposed model is evaluated by the experimental aluminium alloy, and multi-level loading of 45 steel. Fatigue lives data for two-level loading, multi-level loading of LY12CZ predicted are within a factor of 2 scatter band. 展开更多
关键词 multiaxial fatigue fatigue damage rule nonproportional loading variable amplitude loading
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Injustice in Primitive Accumulation and Its Linearity: China's Alternative Path
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作者 Lin Xi 《Fudan Journal of the Humanities and Social Sciences》 2011年第4期93-116,共24页
Primitive accumulation refers to during industrialization. This article argues that the early phase of development this Marxist concept implicates a deeper notion of injustice, which contains logic of linearity that c... Primitive accumulation refers to during industrialization. This article argues that the early phase of development this Marxist concept implicates a deeper notion of injustice, which contains logic of linearity that can be further dissected into a trichotomous part worthy of our discussion, namely, temporal ordering, harsh treatment, and inhumane consequences. This "linearity" as assumed in this concept, nevertheless, was not unchallenged in history. As a matter of fact, in Mao's era, China deliberately sought an alternative path to the capitalist mode by attending to social welfare, physical well-being and rights protection for workers. This part of history is well worth re-investigation and re-interpretation. 展开更多
关键词 INJUSTICE primitive accumulation distributive injustice linear historicity alternative path
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