基于改进遗传算法的Web服务优化组合研究

为了获得更优的Web服务优化组合方案,提出一种基于改进遗传算法的Web服务优化组合方法。首先将Web服务组合优化方案的可行解看作遗传算法的个体。然后通过遗传算法模拟自然界的生物进化过程,找到Web服务组合的最优解,同时在标准遗传算法引入多尺度交叉算子和信息共享因子,提高问题的求解速度。最后进行仿真对比实验。结果表明,改进遗传算法可以快速、准确找到Web服务组合问题的最优解,为解决Web服务组合问题提出了一种新的解决思路。     

增强多目标遗传算法下的组合服务的容错能力

利用多目标遗传算法得到一组满足约束条件的最优非劣方案集,用户根据实际需要从中选择满意的组合方案,同时,未被选择的流程作为备选方案以便发生意外时替代执行。提出了最优非劣方案的失效成功率和基本服务的相容性计算方法,选择可用性高且失效成功率较高的组合方案,以便执行发生意外时组合服务有较高的概率成功切换到备选方案继续执行,增强了组合服务执行的容错能力。实验结果说明了该方法的可行性和有效性。     

遗传算法求解单目标柔性流水车间调度问题研究

为了研究单目标的柔性流水车间的调度问题,完成对此类复杂的组合优化问题的求解,求最小化最大完工时间,提出解决该问题的方法为通过遗传算法对所有解空间进行全局搜索最优解。并且用此方法在进行加工机器选择时用轮盘赌的方法来选择个体,达到优化初始种群的目的。接着对此不确定问题的进行数学模型的建立,确定优化总目标为所有待加工工件加工完成的最小化完工时间。然后通过遗传算法对问题模型求解最优解和最优调度方案。最后,用Matlab进行模拟仿真求出最优结果。     

基于组合算法的嵌入式系统软硬件划分方法

嵌入式系统软硬件划分是一个多约束条件、多目标的组合优化问题,单一算法难以找到最优设计方案,为此,提出一种遗传算法和粒子群算法组合的嵌入式系统软硬件划分方法。首先建立嵌入式系统软硬件划分问题的数学模型,然后利用遗传算法找到问题的可行解,最后采用粒子群算法找到最优方案,并采用仿真实验测试算法的性能。仿真结果表明,该方法提高了嵌入式系统软硬件划分问题的求解效率,可以快速找到更优的软硬件划分方案。     

模拟退火遗传算法对无线传感器网络部署研究

研究无线传感器节点部署优化问题,传感器网络节点的部署在一定程度上决定了网络的性能和使用寿命.传统的遗传算法在无线传感器节点部署优化过程中,由于交叉和变异的概率是固定的,易产生局部最优问题,导致部署不理想,网络生命周期过短.为了更好地优化网络部署,提高网络生命周期,提出了一种基于模拟退火遗传算法的无线传感器节点部署优化方法.方法将传感器节点部署转化为一个组合优化问题,网络节点离散成为网格,通过遗传算法进行最优部署方案的搜索,同时采用模拟退火算法对遗传算法的种群进行更新,提高了最优解的搜索速度.仿真结果表明,模拟退火遗传算法部署的效率高,网络存活的节点数更多,有效地延长了网络的生命周期.     

基于遗传算法的集装箱后方堆场箱位分配策略*

根据重庆港实际情况建立了以提箱时间为制约因素,以最小化翻箱率为目标的集装箱后方堆场箱位分配模型,并针对模型提出了基于遗传算法的解决方案。方案对一次卸船或者进港的一批箱进行全局优化,并考虑其分配对后续集装箱的影响。遗传算法迭代过程中采用适应度函数指数变换防早熟,采用可行解替换法处理约束,并设计最优解保存策略保证最终的优化效果。最后针对实际堆场的不同规模,对方案的优化结果同文献中的其他遗传算法方案进行比较,证明了本文优化策略的优越性和实用性。     

基于杂交遗传算法的多处理器硬实时容错调度算法

传统的硬实时容错调度算法获得了较好的容错性能,但其任务拒绝率、处理器分配偏差比例以及最早完成时间等性能参数不佳,对此提出一种基于杂交遗传算法的优化方案,并对传统的硬实时容错算法进行优化。采用了中心型调度模型,并采用了任务备份方案来实现容错能力。将任务拒绝率、处理器分配偏差比例以及最早完成时间三个优化参数作为遗传算法适应度目标函数的三个带权分量,对其进行优化,通过遗传算法的杂交与迭代计算获得了优化的结果。最终使用不同的任务数量与处理器数量的组合对本算法与传统算法进行对比试验,结果可看出本算法的3个优化参数明显优于传统算法,且总适应度值亦比传统算法有明显改进。     

面向方案组合优化设计的混合遗传蚂蚁算法

提出了方案组合优化数学模型.该模型定义了方案功能载体间的广义距离,以广义距离函数作为方案组合优化的目标函数,以方案的性能要求作为约束条件进行优化并获得方案的最优解.在求解该数学模型的过程中,将遗传算法和蚂蚁算法进行改进并融合形成混合算法.实验结果表明,该混合算法较好地解决了方案设计过程中由多个方案组合难以获得优化解的问题.     

改进模拟退火遗传算法的3D NoC低功耗映射

功耗优化是NoC设计的重要部分,针对将IP (intellectual property)核合理映射NoC的问题,提出一种初始种群优化的模拟退火遗传映射算法.首先以功耗优化为主要目标,通过对初始种群选取方法进行改进来获取功耗更低的映射方案,并针对遗传算法局部最优问题,在遗传算法交叉操作阶段结合模拟退火算法,得到全局最优方案.实验在Windows系统下采用C++语言实现,结果显示,与传统的遗传算法相比,该算法具有较好的收敛性,能快速搜索到较优解,在124个IP核的情况下,采用改进的模拟退火遗传算法进行映射产生的平均功耗比使用遗传算法时降低了32.0%.     

基于多目标遗传算法的多选择Web服务组合方法

为了在服务组合过程中高效地发现、选择满足用户要求的Web服务,提出一种基于Pareto多目标遗传算法的QoS全局最优服务选择算法（PGA-WS）用以实现用户对组合服务质量的要求。该方法产生一组满足约束条件的Pareto最优方案集合,用户根据实际需要或目标函数的偏好,从Pareto最优集中挑选最满意的组合方案作为组合服务选择问题的最优决策方案。实验结果说明了算法的可行性和有效性。     

Neural-optimal control algorithm for real-time regulation of in-line storage in combined sewer systems

Attempts at implementing real-time control systems as a cost-effective means of minimizing the pollution impacts of untreated combined sewer overflows have largely been unsustained due to the complexity of the real-time control problem. Optimal real-time regulation of flows and in-line storage in combined sewer systems is challenging due to the need for complex optimization models integrated with urban stormwater runoff prediction and fully dynamic routing of sewer flows within 5–15 min computational time increments. A neural-optimal control algorithm is presented that fully incorporates the complexities of dynamic, unsteady hydraulic modeling of combined sewer system flows and optimal coordinated, system-wide regulation of in-line storage. The neural-optimal control module is based on a recurrent Jordan neural network architecture that is trained using optimal policies produced by a dynamic optimal control module. The neural-optimal control algorithm is demonstrated in a simulated real-time control experiment for the King County combined sewer system, Seattle, Washington, USA. The algorithm exhibits an effective adaptive learning capability that results in near-optimal performance of the control system while satisfying the time constraints of real-time implementation.     

基于LabWindows/CVI的排水管道机器人测控系统设计

介绍了国内排水管道现状及检测与维护情况,针对排水管道机器人特殊的作业环境,设计了一种基于LabWindows/CVI的排水管道机器人测控系统。该系统以PLC为核心,采用电涡流位移传感器与摄像头结合检测管道缺陷,引入模糊控制算法,增强了系统的鲁棒性和可靠性。通过基于LabWindows/CVI虚拟仪器设计的上位机软件与下位机PLC实时通信,实现了系统对机器人动作的控制,以及数据的采集、处理、存储、显示等功能。整个系统人机交互简单、抗干扰性强、可靠性好,可满足机器人作业时的清理和检测要求。     

Minimization of combined sewer overflows by large-scale mathematical programming

There is a critical need for the development and implementation of control strategies for minimizing receiving water pollution caused by overflows from urban combined sewer systems. Automation and control of such systems has risen as a viable approach to this problem. Control is carried out through regulation of ambient and/or auxiliary storage in the system. The goal is to detain storm flows in the system long enough to prevent flows of a magnitude that exceeds treatment plant capacity, thereby reducing overflow into receiving waters. The problem is first attacked by dividing the large combined sewer system into several mildly interconnected subsystems for which control logic can be developed from application of mathematical programming algorithms consistent with the special characteristics of each subsystem. A flow-projection technique is developed for subsystems not amenable to direct solution by standard optimization techniques.     

The control of sewage sampling using a portable computer

Software to control automatic samplers for sampling sewage flows has been developed for use on a Golden River Conquest Environmental Computer. The equipment is being used in Dundee as part of the UK National study currently underway investigating the polluting effects of sewage sludges that are washed out of combined sewers under storm conditions. Sewage is sampled automatically by samplers that are triggered from a control computer that is monitoring rising water levels in a sewer during storm and dry weather conditions. Increases in sewer flow cause entrainment of previously deposited sewage sludges which are potentialy very polluting if they reach a watercourse via a storm sewage overflow.Experience gained so far has shown that the Conquest computer is ideally suited to use in harsh sewer environments. Problems have been encountered, however, in maintaining power in the battery-operated computer sufficient to ensure that the requisite regular monitoring for rising water levels is being made. The solution to this problem has been to allow the computer to switch-off by going into a ‘sleep’ mode, awakening only to check sewer flow levels once every fifteen minutes. As a rise in level is noted, the ‘sleeping’ time is reduced and levels are monitored every one minute, with an ensuing fully operational state for the computer occurring only once levels reach a certain predetermined threshold.The polyFORTH software developed for this system is described, together with details of the sampling system and early results from the sewer flow quality monitoring study underway.The paper concludes that recent advances in the mathematical modelling of sewer flows and the associated quality implications for receiving watercourses have only been possible because of the parallel developments in computational systems for use in harsh environments such as sewers.     

Evolutionary algorithm enhancement for model predictive control and real-time decision support

Effective decision support and model predictive control of real-time environmental systems require that evolutionary algorithms operate more efficiently. A suite of model predictive control (MPC) genetic algorithms are developed and tested offline to explore their value for reducing combined sewer overflow (CSO) volumes during real-time use in a deep-tunnel sewer system. MPC approaches include the micro-GA, the probability-based compact GA, and domain-specific GA methods that reduce the number of decision variable values analyzed within the sewer hydraulic model, thus reducing algorithm search space. Minimum fitness and constraint values achieved by all GA approaches, as well as computational times required to reach the minimum values, are compared to large population sizes with long convergence times. Optimization results for a subset of the Chicago combined sewer system indicate that genetic algorithm variations with a coarse decision variable representation, eventually transitioning to the entire range of decision variable values, are best suited to address the CSO control problem. Although diversity-enhancing micro-GAs evaluate a larger search space and exhibit shorter convergence times, these representations do not reach minimum fitness and constraint values. The domain-specific GAs prove to be the most efficient for this case study. Further MPC algorithm developments are suggested to continue advancing computational performance of this important class of problems with dynamic strategies that evolve as the external constraint conditions change.     

城市排污系统对河流水质影响的仿真研究

以城市废水系统的集成化管理为出发点，基于国际水协会河流水质1号模型(RWOMI)，确定了适合仿真与实时控制的简化的动态河流水质模型，在MATLAB仿真环境下建立了一个以河流为核心的集成化城市废水系统的简单仿真环境。以某河流城区段为背景，采用国际水协会发布的污水负荷和组分数据作为原始输入，模拟了排水管网和污水处理厂在不同运行条件下引起的河流水质的变化情况。仿真结果表明排水管网组合下水溢流和污水处理厂排放物的处理程度对河流水质会产生直接影响，为集成化管理提供了依据。     

基于DSP2407高精度工业缝纫机驱动系统设计

针对工业缝纫机对速度控制的高精度的要求,采用了同步电机作为驱动电机,它采用DSP作为中央处理器,通过矢量控制和SVPWM算法,能够精确地控制电机的速度具有成本较低的优点。     

Measuring and modelling sewer pipes from video

This article presents a system for the automatic measurement and modelling of sewer pipes. The system recovers the interior shape of a sewer pipe from a video sequence which is acquired by a fish-eye lens camera moving inside the pipe. The approach is based on tracking interest points across successive video frames and posing the general structure-from-motion problem. It is shown that the tracked points can be reliably reconstructed despite the forward motion of the camera. This is achieved by utilizing a fish-eye lens with a wide field of view. The standard techniques for robust estimation of the two- and three-view geometry are modified so that they can be used for calibrated fish-eye lens cameras with a field of view less than 180°. The tubular arrangement of the reconstructed points allows pipe shape estimation by surface fitting. Hence, a method for modelling such surfaces with a locally cylindrical model is proposed. The system is demonstrated with a real sewer video and an error analysis for the recovered structure is presented.     

A methodological approach to the design of optimising control strategies for sewer systems

This study focuses on designing an optimisation based control for sewer system in a methodological way and linking it to a regulatory control. Optimisation based design is found to depend on proper choice of a model, formulation of objective function and tuning of optimisation parameters. Accordingly, two novel optimisation configurations are developed, where the optimisation either acts on the actuators or acts on the regulatory control layer. These two optimisation designs are evaluated on a sub-catchment of the sewer system in Copenhagen, and found to perform better than the existing control; a rule based expert system. On the other hand, compared with a regulatory control technique designed earlier in Mollerup et al. (2015), the optimisation showed similar performance with respect to minimising overflow volume. Hence for operation of small sewer systems, regulatory control strategies can offer promising potential and should be considered along more advanced strategies when identifying novel solutions.     

Integrated urban hydrologic and hydraulic modelling in Chicago,Illinois

With rapidly growing urbanization, urban flooding and water quality control are becoming a vital component of sustainable urban infrastructure. Integrated urban hydrologic and hydraulic modelling represents a potential framework for capturing system interactivity and optimizing the design, operation, and engineering of urban systems. This work describes how a widely-used hydrodynamic model, the Environmental Fluid Dynamics Code (EFDC), was made compliant with the Open Modelling Interface (OpenMI) standard. The new version of the EFDC has potential to be coupled with any OpenMI-compliant model for various studies. As an example, this paper presents an application of the OpenMI version of EFDC coupled with InfoWorks-CS for a representative highly urbanized area in the city of Chicago, Illinois, United States. The integrated modelling simulates the two-way linkage between the sewer network and the Chicago Area Waterway System (CAWS). This interaction between the river and sewer pipe systems can not be described by decoupled models. By coupling the models, it is possible to observe the interaction between the sewer system overflow discharge and the hydraulic head in the pipe network. This is particularly important since higher water levels in the pipe system increase the potential for flooding.