Improved understanding of combined sewer systems using the Illinois Conveyance Analysis Program (ICAP)

Understanding the conveyance of sewer networks is vital, especially in cases of great variability in flow rates, such as in combined sanitary and storm sewer systems. Conventional conveyance studies in sewer systems often have extended computation times due to complexity of the solution, or alternatively make assumptions that ignore the water-surface profile within a pipe. In previous research, the hydraulic performance graph (HPG) was successfully used for open-channel capacity determination. The HPG summarizes the results of many backwater calculations for a reach so that these calculations do not need to be repeated. This article describes algorithms utilized by the Illinois Conveyance Analysis Program that uses the HPGs to describe the conveyance of a system, identify bottlenecks for varying conditions, conserve mass by tracking outflow and overflows under stepwise steady flow conditions. The software is freely available at https://github.com/obergshavefun/icap/wiki.     

基于改进的鸡群算法在云计算资源调度中的研究

针对云计算中的资源调度效率低的问题,提出将改进后的鸡群算法用于调度。引入反向学习概念对鸡群种群进行初始化,提高全局搜索能力。对小鸡的位置引入了粒子群算法中的权重值和学习因子的概念进行改进,优化了鸡群个体位置,通过差分算法对鸡群算法整体的个体位置进行优化,最后通过边界处理从整体上预防了算法中个体位置可能出现的越界。在仿真实验中,将优化后的鸡群算法与基本鸡群算法,粒子群算法和蚁群算法进行在完成时间、花费成本、能量消耗和负载均衡中进行了对比,取得了较好的效果。     

Gross solids from combined sewers in dry weather and storms,elucidating production,storage and social factors

Variation in rates of sanitary hygiene products, toilet tissue and faeces occurring in sewers are presented for dry and wet weather from three steep upstream urban catchments with different economic, age and ethnic profiles. Results show, for example, that total daily solids per capita from the low income and ageing populations are almost twice that from high income or ethnic populations. Relative differences are verified through independent questionnaires. The relationship between solids stored in sewers prior to storms, antecedent dry weather period and the proportion of roof to total catchment area is quantified. A full solids’ flush occurs when storm flows exceed three times the peak dry weather flow. The data presented will assist urban drainage designers in managing pollution caused by the discharge of sewage solids.     

改进的鸡群算法并用于多分类器系数优化

针对鸡群算法因雄鸡粒子易陷入局部最优而无法取得全局最优问题,提出了基于杂交的改进的鸡群算法。即在雌鸡粒子更新后加入杂交机制,使雌鸡粒子加速离开局部最优点;同时通过更新机制将性能优越的雌鸡粒子设定为雄鸡粒子来避免雄鸡粒子陷入局部最优,并将改进的鸡群算法用于多分类器系数的优化。仿真实验结果表明,改进的鸡群算法不易陷入局部最优,且用该算法优化的多分类器其错误率降低,训练时间缩短。     

巢湖市排水系统雨天溢流污染控制策略

合流制系统改造及溢流污染控制是黑臭河道治理的核心工作之一。文中在总结国内外合流制溢流污染(CSO)治理措施的基础上,论述了巢湖市排水系统溢流污染控制策略。系统分析了合流制溢流污染产生的原因,依据巢湖市污染排查和管网检测等前期研究相关结果,提出了整体控制策略;并选取典型区域小王庄中沟,提出针对典型区域合流制系统的控制措施,即在现有管网的基础上,借助管网系统与系统之间的互调性以及末端调蓄控制手段,对整个管网的污水运行及入河排放进行污染物溢流污染控制。     

京广铁路北京中心城区段廊道绿地生态系统文化服务供应潜力与机会

城区铁路廊道两侧的防护绿地长期处于废弃状态,而正在运营的铁路线路为城市储备了大量的防护绿地。在满足隔音、防护功能的前提下,探究铁路廊道绿地为沿线城市空间提供生态系统文化服务(CES)的潜力和机会。以北京中心城区内京广高速铁路、京广普速铁路两侧绿地为研究对象,以铁路线两侧1 km的城市空间为范围,在现有研究基础上,建立铁路廊道绿地CES供应的研究框架,包括供应潜力和供应机会两方面。研究认为：1)现存的景观要素可以转化为植物、水体、游憩活动、场地与交通、管理与维护5类,待补充要素主要集中在设施的完善与后期管理与维护方面,提出“识别-转化与补充-供应”的途径;2)研究区内西三环至西五环之间是沿线CES供应机会较高区域,园博园以南区域供应机会一般,研究范围东侧边界至西三环和园博园区域CES供应机会较低。基于以上结果,提出铁路廊道绿地供应CES功能的具体建议。城区铁路廊道绿地CES供应潜力和机会研究是中观尺度下CES功能的空间化研究,其定量化的研究将为沿线交通空间的精细化治理提供基础资料和理论指导。     

基于CSO-SVR的低压架空线路谐波损耗评估

针对低压架空线路物理解析模型谐波损耗计算精度不高的问题,文中提出采用基于纵横交叉优化(CSO)算法的支持向量回归(SVR)模型对架空线路谐波损耗进行评估。首先,采用结构风险最小化设计的SVR模型,拟合线路特征与谐波损耗之间的关系。然后,利用CSO算法对SVR超参数进行全局搜索,以动态优化获取最优超参数组,建立CSO-SVR谐波损耗评估模型。文中依托国内某大型电能质量综合试验平台进行低压架空线路谐波试验,获得线路谐波损耗实测数据,并基于该数据对所提模型进行验证。结果表明,采用CSO算法对SVR超参数进行优化,可有效提升SVR模型的谐波损耗评估性能。与其他模型相比,所提模型的评估精度更高。     

Using the duration of combined sewer overflow events for the calibration of sewer hydrodynamic models

This paper compares two calibration approaches to enhance the ability of hydrodynamic models to describe the performance of combined sewer overflow (CSO) structures. One approach is based on the duration of CSO events (monitored by low-cost sensors) and the other focuses on the overflow volume. Both were applied to the West-Graz catchment model to simulate the discharge from the CSO overflow channel under small, medium and large rain episodes. The methodology includes sensitivity analysis of the model parameters and automatic calibration through optimization. The results revealed that the calibration using the CSO duration led to results similar to those of the approach that used overflow volume, with less than 12% error differences between approaches for medium and large rain episodes.     

Computational fluid dynamics based assessment of discharge-water depth relationships for combined sewer overflows

This article describes a general method to assess discharge-water depth relationships for combined sewer overflow (CSO) chambers. This method is particularly suitable for: complex geometries, unavailable univoc relationship between upstream and downstream flow and complex downstream hydraulic conditions. The methodology presented in this article is based on computational fluid dynamics. Its aim is to propose a relationship between the water depths in the CSO chamber and the overflow discharge. This study focuses on the evaluation and integration of the uncertainties in the determination of the most suitable depth-overflow relationship. Uncertainties related to numerical model, boundary conditions and water depth have been taken into account in order to elaborate water depth-overflow rate relationship. This approach is illustrated through the example of the ‘Milan’ CSO of Mulhouse city, France.     

合理计算有线电视系统指标

结合宁波市有线电视网络改造实践，阐述有线电视工程设计中必要的系统指标计算，并就选用优质设备提高网络质量等问题进行探讨。