基于GA-PSO算法的路径测试数据自动生成*

为了实现测试数据自动生成,许多遗传算法及其改进算法应用到了测试领域。针对遗传算法具有较强的全局搜索能力,但局部搜索能力较弱,且收敛速度慢的特点。将遗传算法与粒子群算法结合起来形成新的混合算法（GA-PSO）,并成功应用到软件测试数据自动生成过程中。实验结果表明,该算法结合了遗传算法和粒子群算法的优点,在保证软件测试数据正确生成的情况下,极大地提高了数据生成的效率。     

Automated sub-zoning of water distribution systems

Water distribution systems (WDS) are complex pipe networks with looped and branching topologies that often comprise thousands to tens of thousands of links and nodes. This work presents a generic framework for improved analysis and management of WDS by partitioning the system into smaller (almost) independent sub-systems with balanced loads and minimal number of interconnections. This paper compares the performance of three classes of unsupervised learning algorithms from graph theory for practical sub-zoning of WDS: (1) Global clustering – a bottom-up algorithm for clustering n objects with respect to a similarity function, (2) Community structure – a bottom-up algorithm based on the property of network modularity, which is a measure of the quality of network partition to clusters versus randomly generated graph with respect to the same nodal degree, and (3) Graph partitioning – a flat partitioning algorithm for dividing a network with n nodes into k clusters, such that the total weight of edges crossing between clusters is minimized and the loads of all the clusters are balanced. The algorithms are adapted to WDS to provide a practical decision support tool for water utilities. Visual qualitative and quantitative measures are proposed to evaluate models' performance. The three methods are applied for two large-scale water distribution systems serving heavily populated areas in Singapore.     

Modelling errors, entropy and the hydraulic reliability of water distribution systems

This paper reports on an investigation of the possible influence of modelling errors on the relationship between the entropy and hydraulic reliability of water distribution systems. The errors are due to minor differences between the design optimisation and subsequent simulation models, which lead to small discrepancies between the capacity of the network and the required supply. Pressure-dependent analysis was used for the hydraulic simulations. It is shown that any correlation between the redundancy or undercapacity due to the modelling errors and the hydraulic reliability is insignificant. The results, therefore, provide yet more evidence that the entropy-reliability relationship is strong.     

Use of modelling error dynamics for the calibration of water distribution systems

The calibration of a water distribution system remains a complex task. Leakages create additional difficulties if their proportion is high. Not all leakages are real. A part of them are apparent leakages. An optimization procedure is proposed to obtain the proportions of real and apparent leakages. The distribution of the leakages over a WDS may be made easier by analyzing the dependence of modelling errors on water flow. It is suggested that pressure measurements should be ranked according to the closeness of measurement to the water source and that modelling errors should be analysed separately for the measurements of different order (from the first to the highest). The advantage of this approach is that the analysis is confined within points of measurements of one order and it allows to redistribute fluxes of leakages (real and apparent) more reliably. Nonlinear optimization with linear constraints is used for the redistribution of leakages over a WDS. The methodology proposed allows to exclude the influence of systematic errors on the result of calibration.     

混合粒子群算法的软件测试数据自动生成

针对全连接拓扑结构的粒子群算法在生成测试数据过程中,存在收敛精度低,易陷入局部极值的问题,提出一种混合粒子群算法HPSO,并将其应用于测试数据自动生成。该算法在保证全局收敛性的前提下,对多样性匮乏的种群,首先采用定长环形拓扑结构取代粒子群的全连接拓扑结构;其次,采用轮盘赌方法选择候选解,更新粒子位置信息和速度信息;最后引入条件禁忌算法,对处于局部极值的粒子采取禁忌处理。通过实验比较表明:与基本粒子群算法(BPSO)相比,HPSO使种群多样性得到大幅度提升;在测试数据生成性能上,HPSO的搜索成功率和路径覆盖率均优于遗传算法与粒子群算法混合算法GA-PSO,而平均耗时与BPSO算法相当,性能表现优越。     

基于改进SPEA2算法的给水管网多目标优化设计

针对给水管网多目标优化设计问题,将管网造价、节点富余水头总和以及节点富余水头方差设为目标函数,从经济性和可靠性两方面对给水管网进行优化。为了获取多样性和收敛性好的解,本文结合选择机制中支配和分解的思想,引入参考向量到强度帕累托进化算法（strength Pareto evolutionary algorithm 2, SPEA2）中,配合支配强度进行解的选择。通过双环管网和纽约管网两个管网案例,仿真结果表明了所提算法在解决管网多目标优化设计问题上的有效性,并最终应用于实际的管网工程建设中。     

Semi-formal design of reliable mesh generation systems

A reliable mesh generation infrastructure is designed based on software engineering principles. Formal methods, software design documents and clear modular decomposition criteria are introduced to improve the quality of mesh generation software. The design document for a simple 2D mesh generation data structure is presented using a semi-formal specification. The proposed semi-formal documentation system avoids any ambiguity during the software design process and will help in driving the software test cases. Using the proposed software, design techniques result in a consistent software design that is easy to extend and modify.     

基于循环神经网络的正交网格的自动化生成算法

随着计算机图形学、工业设计、自然科学等领域的飞速发展,对高质量的科学计算方法的需求随之增大,而这些科学计算的方法离不开高质量的网格生成算法。对于常用的正交网格生成算法,是否能减少计算量以及是否能降低的人工干预等问题仍是它们所面临的主要挑战。针对这些挑战,对于单连通的目标区域,提出了基于循环神经网络之一的长短期记忆网络（LSTM）和Schwarz-Christoffel共形映射（SC映射）的正交网格自动化生成算法。首先,利用基于SC映射的Gridgen-c工具的基本条件将网格生成问题转换为一个带线性限制条件的整数规划问题。接着,利用预处理后的GADM数据集和LSTM训练获得能计算目标多边形区域每个顶点转角类型的概率的分类器。该分类器可以大幅度降低整数规划问题的时间复杂度,使该问题能被自动化且快速地求解。最后以简单图形区域、动画图形区域、地理边界区域为样例,进行网格生成实验。结果表明：对于简单图形区域,所提算法均能达到最优解;而对于具有复杂边界的动画图形区域和地理边界区域,实例网格结果表明,所提算法能使这些目标区域的计算量分别降低88.42%和91.16%,且能自动化地生成较好的正交网格。     

An integrated planning tool for design of recycled water distribution networks

Pipeline design of urban recycled water networks involves thousands of decisions to ensure delivery of water to multiple use locations with pipelines and pump stations correctly located, optimally sized, and compatible with existing infrastructure. Here, we introduce PRODOT, Pipeline ROuting and Design Optimization Tool, software that identifies near-minimum-cost pipeline routes; accounts for existing configurations, legal, environmental or safety concerns, and trade-offs in pipeline length, pipe installation methods, traffic congestion during construction; optimizes pump station locations, pumping energy, pipe diameters and pressure classes; and includes theoretical additional capacity of each pipe, facilitating future expansion. We illustrate the utility of PRODOT with a case study for a local utility comparing PRODOT-generated configurations to a configuration proposed by an experienced consulting firm. The comparison shows that PRODOT produces pipeline configurations similar to the consulting firm's proposal with improvements by effectively and more broadly incorporating options the consultant may not have considered.     

基于序列到序列神经网络模型的古诗自动生成方法

计算机写诗是实现计算机写作的第一步,目前计算机写诗普遍存在主题不明确、诗的内容与写作意图不一致的问题。为改善这些问题,效仿古人写诗的过程,提出了一种两个阶段生成古诗的方法。第一阶段获取写诗大纲,采用TextRank算法对用户输入文本提取关键词,并提出一种基于注意力机制的序列到序列神经网络模型用于关键词扩展;第二阶段根据写诗大纲生成每一行诗句,并提出一种包含双编码器和注意力机制的序列到序列神经网络模型用于古诗生成。最后通过对实验结果的评估验证了提出方法的有效性。与基准方法相比,该方法生成的古诗的主题意义更加明确,诗所表现的内容和写作意图更加一致。     

A statistically based fault detection and diagnosis approach for non-residential building water distribution systems

Large non-residential buildings can contain complex and often inefficient water distribution systems. As requirements for water increase due to water scarcity and industrialization, it has become increasingly important to effectively detect and diagnose faults in water distribution systems in large buildings. In many cases, if water supply is not impacted, faults in water distribution systems can go unnoticed. This can lead to unnecessary increases in water usage and associated energy due to pumping, treating, and heating water. The majority of fault detection and diagnosis studies in the water sector are limited to municipal water supply and leakage detection. The application of detection and diagnosis for faults in building water networks remains largely unexplored and the ability to identify and distinguish between routine and non-routine water usage at this scale remains a challenge. This study using case-study data, presents the application of principal component analysis and a multi-class support vector machine to detect and classify faults for non-residential building water networks. In the absence of a process model (which is typical for such water distribution systems), principal component analysis is proposed as a data-driven fault detection technique for building water distribution systems for the first time herein. Hotelling T²-statistics and Q-statistics were employed to detect abnormality within incoming data, and a multi-class support vector machine was trained for fault classification. Despite the relatively limited training data available from the case-study (which would reflect the situation in many buildings), meaningful faults were detected, and the technique proved successful in discriminating between various types of faults in the water distribution system. The effectiveness of the proposed approach is compared to a univariate threshold technique by comparison of their respective performance in the detection of faults that occurred in the case-study site. The results demonstrate the promising capabilities of the proposed fault detection and diagnosis approach. Such a strategy could provide a robust methodology that can be applied to buildings to reduce inefficient water use, reducing their life-cycle carbon footprint.     

基于漏洞的蠕虫特征自动提取技术研究

提出一种新的基于漏洞的蠕虫特征,其区别于传统的基于语法或语义分析的技术,对蠕虫攻击的漏洞特征进行分析,将该算法应用于检测系统中。通过实验证明,该检测系统能有效地检测出各种多态变形蠕虫。     

基于共享单车GPS数据的小区道路生成方法

利用GPS数据生成路网对城市交通有着重要意义。由于机动车自身对道路条件的要求,利用机动车GPS提取路网主要针对城市主干道及主路,忽略了小路及小区路网。为完善城市路网,提出了一种基于共享单车GPS轨迹的道路拓扑结构生成方法。首先提取路网拓扑节点,通过引入趋势夹角判断转折点后利用转向角分析确定拓扑点。然后提取道路线型,通过OW(opening window)算法对轨迹进行分割、基于DBCSAN算法思想提出一种对子轨迹聚类方法,再提取特征点来拟合道路中心线。利用缓冲区验证路网的精度,结果表明该方法生成的道路既能确保拓扑结构又具有较高的覆盖率。     

Peaking demand factor-based reliability analysis of water distribution systems

Water demands vary and consideration of the probabilistic nature of the variations should lead to more instructive assessments of the performance of water distribution systems. Water consumption data for several households were analysed using the chi-square technique and it was found that distributions worth considering under certain circumstances include the normal and lognormal.Reliability values were calculated for a range of critical demand values and the corresponding confidence levels determined from the probability distributions. Water consumption was assumed to be pressure dependent and the modelling of the water distribution system was carried out accordingly. This peaking factor approach coupled with the statistical modelling of demands provides a more realistic way of incorporating variations in demands in the evaluation and reporting of system performance than the traditional single demand value approach in that the extent to which a network can satisfy any demand and the probability that the demand will occur can be recognized explicitly. The method is illustrated by an example.     

高速环境下基于数据分流的入侵检测系统设计

提出了一种数据分流的方法,将捕获的网络数据包按某种策略分流转发至多个检测设备进行处理,提高了在高速网络环境下检测系统的性能,解决了硬件发展跟不上网速发展而带来的漏报率高的问题。     

基于数据挖掘的智能配电站房运行状态评估方法

为解决智能配电站房的在线监测与预警评估问题,提出了一种基于数据挖掘的智能配电站房运行状态评估方法。首先建立配电站房多源数据信息阵列,对当前时刻之前一段时间内配电站房内部的温度信息、湿度信息、水侵信息、烟雾信息、开关遥测信息、开关遥控信息进行描述;其次通过配电站房多源数据评估阵对智能配电站房多源数据信息阵进行了量化评估;然后对配电站房多源数据评估阵进行每列量化综合以生成配电站房多源数据单项评估阵;最后基于加权平均方法对配电站房多源数据单项评估阵进行综合,生成智能配电站房运行状态评估指标。实例分析验证了本文所提方法的可行性,可满足现场工程实际需求。     

Minimum volume ellipsoid classification model for contamination event detection in water distribution systems

The presented study features an event detection model alerting for contamination events in water distribution systems. The developed model comprises a minimum volume ellipsoid (MVE) classifier, detecting outlier measurements, and a following sequence analysis utilizing the MVE binary output, for the classification of events. The model is updated continuously and exploits a constantly growing data base. The MVE enables simultaneous analysis of the water quality parameters. The multivariate analysis explores the relations between water quality parameters and detects changes in their common patterns. The suggested model applied an un-supervised classification method, eliminates the need for simulated events examples in the classifier construction. In the absent of satisfying information regarding the influence of contamination event on the parameter measurements, eliminating the use of any assumption contributes to the model reliability and generality. The model was trained on a real water utility data, and tested on randomly simulated events that were superimposed on the original data base. The model showed high accuracy and detection ability compared to previous studies.     

Spatial event classification using simulated water quality data

This study deals with the integration of contamination simulations and a spatial event detection model. The simulation of contaminant intrusion includes detailed chemical-specific reactions within a multi-species water quality model. This set-up generates a scenario of contaminant distribution and produces a continuous multiple sensor stations database. Three organophosphates pesticides, Chlorpyrifos, Malathion, and Parathion, are modeled as possible contaminants. The event detection model comprises both local and spatial data analysis. The local model applies a previously developed single-sensor event detection model with a higher alert threshold that reduces false alarm rates. The spatial model considers upstream sensor datasets which are examined for their uniqueness and mutual resemblance in a sliding time window. The model utilizes outlier detection, data analyses, and network hydraulics for the detection of suspicious spatial trends. The proposed algorithm is capable of detecting events with low contamination signatures and spatial influence. Two case studies are explored and compared to the single sensor model. The proposed methodology resulted in a lower number of false alarms compared to the previous single sensor event detection modeling approach.     

Multi-objective optimization of water distribution systems based on a real options approach

This paper describes a multi-objective optimization model including Real Options concepts for the design and operation of water distribution networks. This approach is explained through a case study with some possible expansion areas defined to fit different future scenarios. A multi-objective decision model with conflicting objectives is detailed. Also, environmental impacts are considered that take into account not only the life cycle carbon emissions of the different materials used during the construction of the networks but also the emissions related to energy consumption during operation. These impacts are translated by giving a cost to each tonne of carbon dioxide emitted. This work presents a new multi-objective simulated annealing algorithm linked to a hydraulic simulator to verify the hydraulic constraints, and the results are represented as points on the Pareto front. The results show that the approach can deal explicitly with conflicting objectives, with environmental impacts and with future uncertainty.     

GIS在电力配网系统的应用及价值

随着经济社会的转型升级,配电网的规模越来越大。技术与设备密集型企业的增多,对电力配网系统提出了更高的要求。介绍了配电GIS系统的建设意义、系统设计目标及其在电力配网系统中的应用。