基于仿水循环算法的梯级水库群多目标优化调度研究

仿水循环算法(WCA)是一种新的智能种群优化算法,将该方法引入梯级水库群多目标优化调度,并提出多目标仿水循环算法(MWCA)。MWCA通过对自然界水循环过程的模拟,构建多目标下的相对重力机制,实现对非劣解的有效搜索,建立汇流、分流、渗流、蒸发降雨4个搜索策略,提升算法的收敛速度、多样性和局部搜索能力,同时有效克服传统算法的早熟问题,令算法具有较强的全局搜索和收敛性能。在梯级水库群多目标优化调度实例计算中,与多目标粒子群算法MOPSO和多目标遗传算法NSGA-Ⅱ进行比较分析,结果表明MWCA在计算结果和非劣解多样性上均优于其他算法,为梯级水库群多目标优化调度问题提供了一种有效的求解思路。     

基于混沌算法的水库群联合优化调度

利用混沌算法全局搜索能力强、求解速度快的特点,将混沌优化算法运用到水库优化调度中,建立了水库群多目标优化模型,并提出交互式的多目标优化模型求解方法.该方法利用混沌优化算法生成满足约束条件的可行集,再采用交互式决策偏好的方法从非劣解集中寻找最佳权衡解;并对滦河下游水库群进行了实例研究.结果表明算法可行,成果合理,能为水库群的联合调度提供技术支持.     

改进的多目标差分进化算法在水库优化调度中的应用

水库多目标优化调度是一个复杂的系统优化问题,属于高维、多约束、非线性问题的优化领域。智能优化算法在求解水库多目标优化调度时,存在非劣解较少、分布不均匀及不收敛等问题,基于上述问题,提出一种求解新思路,通过加入精英保留机制并用拥挤距离来维持外部精英集改进多目标差分进化算法。建立了多目标水库优化调度模型,并以综合利用的漳河水库多目标优化调度为例进行了求解,结果表明该算法能够得到分布较为均匀的非劣解集,证明方法在水库多目标优化调度中是有效的。     

基于混合粒子群算法的梯级水电站多目标优化调度

提出多目标混合粒子群算法以求解梯级水电站多目标联合优化调度模型。该算法采用混合蛙跳算法的分组-混合循化优化框架以增强算法的全局搜索能力;在族群内通过粒子群算法的飞行调整策略指导个体进化;同时,引入外部精英集,建立了基于自适应小生境的外部精英集维护策略,提高了算法的收敛性和非劣解集的多样性。最后将该算法应用于三峡梯级水电站多目标优化调度工程,计算结果表明,本文算法能够获得计算实时性强、分布均匀、收敛性好的调度方案集,并以此分析明确了调度目标间的耦合关系,可为梯级电站的多目标调度决策提供科学依据。     

基于混合粒子群算法的梯级水电站多目标优化调度

提出多目标混合粒子群算法以解决梯级水电站多目标联合优化调度模型求解的难题。该算法采用混合蛙跳算法的分组－混合循化优化框架,增强算法全局搜索能力,在族群内通过粒子群算法高效灵活的飞行调整策略指导个体进化,同时,引入外部精英集,建立一种基于自适应小生境的外部精英集维护策略,提高算法的收敛性和非劣解集的多样性。最后将该算法应用于三峡梯级水电站多目标优化调度工程应用实例,结果表明,本文算法能够获得计算实时性强、分布均匀、收敛性好的调度方案集,并以此分析明确了调度目标间的耦合关系,为梯级电站的多目标调度决策提供了科学依据。     

基于多重迭代算法的梯级水库群调度图优化方法

基于梯级水库群中各水库的常规调度图,建立了以梯级水库群多年平均发电量最大为目标的梯级水库群调度图优化数学模型,提出了基于多重迭代实现高维模型降维的求解算法,即以轮库迭代法实现空间多水库降维,以轮线迭代法实现单一水库多调度线降维,以逐次优化算法实现调度线状态降维。万安溪-白沙梯级水库群的算例计算结果表明,该优化方法能获得形态合理的优化调度图,并能有效提高水库群发电量。     

长江上游巨型水库群联合蓄水调度研究

以长江上游30座水库巨型水库群为研究对象,建立提前蓄水多目标联合优化调度模型,采用分区策略、大系统聚合分解、参数模拟优化方法和并行逐次逼近寻优算法求解。研究结果表明:所提模型框架可较好地解决巨型水库群联合蓄水优化调度问题;智能算法对于复杂约束的多目标优化问题可产生大量非劣解;Pareto前沿分布范围均匀且广泛,可供决策者灵活调度。与原设计方案相比,在防洪风险得到控制的前提下,通过水库群提前蓄水联合优化调度,水库总蓄满率由90.40%增加到94.42%,年均增发电量76.5亿kW·h(+3.76%),经济社会效益显著。     

基于可行空间搜索遗传算法的梯级水库群调度规则研究

以梯级水库群系统多年平均发电量和旬出力保证率最大为目标函数,以梯级水库群内各水库拐点式调度图为决策变量,建立梯级水库群联合发电调度模型,并采用可行空间搜索遗传算法进行求解。为了避免模型求解过程中对不可行解的过多处理,有针对性地对可行解进行优化。最后,以汉江流域梯级水库群为例,对模型和算法的有效性进行了验证。     

隔河岩和高坝洲梯级水电站水库联合调度方案研究

发电量和保证出力是水库调度的两个对立目标,如何协调发电量和保证出力,是制定水库群联合调度方案的关键。本文对隔河岩和高坝洲梯级水电站水库联合调度,以发电量和保证出力为目标函数,建立了多目标联合优化调度数学模型,并提出了求解多目标优化模型最优解的交互式决策偏好系数法。此方法首先应用约束法将多目标优化模型转换成多个单目标优化模型,采用动态规划法求单目标优化模型的解,得到多目标优化数学模型的不劣解集,在此基础上,提出了一个评价多目标方案的决策偏好系数,并以决策偏好系数为依据,从不劣解集中选择多目标优化数学模型的最优解。应用此方法求出了隔河岩和高坝洲梯级水电站水库联合调度的最佳方案。     

PA-DDS算法在水库多目标优化调度中的应用

Pareto存档动态维度搜索(Pareto-Archived Dynamically Dimensioned Search,PA-DDS)算法是一种求解多目标问题的随机搜索启发式算法。本文将PA-DDS算法引入考虑供水和发电的多目标优化模型优化水库调度图,与非支配排序遗传算法(Non-dominaled Sorting Genetic AlgorithmⅡ,NSGA-II)和多目标粒子群算法(Multi-Objectives Particlce Swarm Optimization,MOPSO)对比了收敛性,并在求得非劣解分布的均匀性和与理论Pareto前端的相似性方面与NSGA-II进行比较,分析该算法求解水库多目标调度问题的优化性能,对比分析不同目标下的优化调度图。结果表明:PA-DDS算法能够得到更高质量的非劣解集,优化调度图与原设计调度图相比,能更有效协调供水和发电的矛盾,在小幅降低(0.96%)发电量的前提下显著提高(8.07%)水库供水量,平均每年增加经济效益0.55亿元。     

地下厂房施工过程的三维非线性数值模拟分析

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。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

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.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…