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应用单亲遗传算法进行树状管网优化布置 总被引:33,自引:5,他引:28
树状管网布置优化属于典型的组合优化问题。本文针对树状管网布置的特点,以图论和遗传算法为理论基础,应用改进遗传算法 单亲遗传算法进行树状管网优化布置,并设计了相应的适应度函数、单亲换位算子和逆转算子。与Dijkstra算法和Kruskal算法相比,单亲遗传算法直接以管网投资最小为优化目标,能够获得一批管网投资最小的布置方案,且算法的寻优效率较高,收敛性和稳定性较好。 相似文献
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用基于整数编码和基因换位变异、随机变异及倒位变异等遗传操作的单亲遗传算法 (IPGA)解水资源最优分配 ,并对该单亲遗传算法的全局收敛性和实用性进行了初步分析 .通过算例说明了该算法的可行性和通用性 相似文献
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解水资源最成分配问题的遗传算法 总被引:2,自引:0,他引:2
用基于整数编码和基因换位变异、随机变异及倒位变异等遗传操作的单亲遗传算法(IPGA)解水资源了优分配,并对该单亲遗传算法的全局收敛性和实用性进行了初步分析。通过算例说明了该算法的可行性和通用性。 相似文献
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应用改进粒子群算法求解松江河梯级水电站短期优化调度问题,建立梯级电站发电量最大和发电效益最大短期优化调度数学模型。针对粒子群算法存在的后期收敛速度慢和易陷入局部最优等缺点,引入收缩因子和基于遗传思想的变异算子对其进行改进。应用改进粒子群算法对松江河梯级水电站进行短期优化调度,分别采用发电量最大和发电效益最大数学模型进行算例分析。结果表明:对梯级电站进行短期优化调度可以提高梯级电站的整体质量和效益;应用改进粒子群算法求解梯级电站短期优化调度问题在求解时间、精度上都取得了满意的效果。 相似文献
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蜂群遗传算法及在水库群优化调度中的应用 总被引:2,自引:1,他引:1
介绍了一种基于蜂群繁殖原理的改进遗传算法--蜂群遗传算法(BSGA),采用改进的遗传算子解决了传统遗传算法中"选择压力"和"种群多样性"之间的矛盾.将该算法应用于梯级水库优化调度的研究中,通过对清江梯级水库群优化调度的实例计算,得到了合理的全局最优解,验证了BSGA的可靠性和实用性. 相似文献
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针对传统土石坝渗流预测模型存在局部最优、抗干扰性差和预测精度低等问题,通过RUN算法优化XGBoost算法得到RUN-XGBoost算法,构建了RUN-XGBoost模型以获得更优的土石坝渗流预测结果。该模型在种群初始化时采用RUN算法对XGBoost算法的3个主要参数进行改进,使预测结果有较高的有效性;通过自动寻找最优参数增进算法的整体收敛速度和预测精度,同时引入随机解,使算法能够排除局部最小值并继续搜索,从而获得全局最优结果。工程实例验证结果表明,RUN-XGBoost模型具有简洁、高效、预测精度高、鲁棒性强等优点。 相似文献
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蜜蜂进化型遗传算法在水库优化调度中的应用 总被引:1,自引:0,他引:1
提出了一种基于蜜蜂进化型遗传算法的水库优化调度问题的求解方法,并通过实例对蜜蜂进化型遗传算法和标准遗传算法的性能做了比较.结果表明,在进化代数相同的条件下,由于蜜蜂进化型遗传算法在配种选择算子上使用种群的最优个体作为蜂王,提高了种群收敛速度;再者,在代进化过程中引入一个随机种群,保持了群体的多样性,提高了算法的勘测能力. 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献