A combined distribution and assignment model for continuous facility location problem

Consider a general, heterogeneous geographical space with a set of competitive facilities, where the customers' demand locations from each of the facilities are continuously dispersed over the area. The total demand generated from a particular location in the space is fixed, but the demands from this location to the set of competitive facilities are subject to a distribution function with respect to the relative transportation costs to these facilities. Furthermore, we take into account congested transportation cost in characterizing customer choices. Congestion effect is explicitly built into our model by using a flow-dependent and location-dependent transportation cost function. The routing behavior of customers over the space and the user equilibrium choices of facilities are modeled by constructing a spatial user equilibrium flow pattern. The problem is formulated as a combined distribution and assignment model. An iterative algorithm between the distribution function for the choice of facilities and a mixed finite element method for route choices is proposed to solve the resulting continuous facility location problem. A numerical example is given to demonstrate the effectiveness of the proposed methodology. Received: May 1999/Accepted: May 2000     

A hybrid simulation approach for quantitatively analyzing the impact of facility size on construction projects

Sizing temporary facilities is a crucial task in construction site layout planning due to its significant impact on project productivity and cost. This paper describes a simulation-based approach for modeling the size of facilities that temporarily contain materials in construction projects. Different methods have been introduced for estimating the required size of this kind of facility; however, space limitations, particularly on congested sites, may not allow the planner to allocate the estimated space to the facilities. This study aims at quantitatively analyzing the impact of facility size on the project and modeling the managerial corrective actions to remedy the space shortage in facilities. To this end, a hybrid discrete-continuous simulation technique is adopted. Simulation is superior in modeling dynamic interactions between variables as well as modeling construction processes with inherent uncertainties. The combination of discrete and continuous simulation is used to enhance accuracy and model the project at both operational level (i.e., activity level with higher level of detail) to estimate production rate, and strategic level (i.e., macro level with lower level of detail) to account for some construction planning decisions such as material management variables. The novelty of this study is analyzing the impact of facility size on the project time and cost, while managerial actions taken to resolve space shortages are modeled, and interdependent influencing parameters of the different disciplines, such as site layout, material management, logistics, and construction process planning are integrated in a unified model. The applicability and suitability of the proposed approach is demonstrated in layout planning of a tunneling project site.     

Sensitivity analysis for a continuum traffic equilibrium problem

This paper develops a sensitivity analysis for the continuum traffic equilibrium problem of a city with several competing facilities. In the city, the customers’ origins are continuously dispersed. We assume that the customer demand is dependent on the total cost of patronizing these facilities. Specific travel cost–flow relationships are considered. The choice of facility in the continuum transportation system follows a user equilibrium principle in which from each origin, no customer can reduce their individual cost to patronize any of the facilities by unilaterally changing route or facility. The problem can be formulated as a minimization problem that is subject to a set of constraints and solved with a finite element method. The sensitivity analysis is based on the implicit function theorem at the equilibrium solution. A numerical example is presented to illustrate the applications of these sensitivity analysis results.     

The application of the ant colony optimization algorithm to the construction site layout planning problem

A good site layout is vital to ensure the safety of the working environment, and for effective and efficient operations. Moreover, it minimizes travel distance, decreases materials handling, and avoids the obstruction of materials and plant movement. Based on studies in the manufacturing industry, the cost of materials handling could be reduced by 20–60% if an appropriate facility layout is adopted. In designing a site layout, a planner will first position the key facilities that influence the method and sequence of construction, and then assign the remaining facilities in the available space that is left over. This process is similar to the positioning of facilities in the ant colony optimization (ACO) algorithm. The general principle of the ACO algorithm is to assign facilities to a location one by one, and the occupied locations are deleted from the location scope in the next assignment. In the study, ACO algorithm is employed to resolve the construction site layout planning problem in a hypothetical medium‐sized construction project. By applying fuzzy reasoning and the entropy technique, the study calculates the closeness relationship between facilities, in which the optimal site layout is affected by the mutual interaction of facilities.     

Towards a general theory of public and private facility location

Theories of public facility locations have followed a rather haphazard pattern. The prevailing “emptiness” reflects the varying kinds of public facilities requiring location. It also reflects the personal-social behavioral basis which underscores selection of public facility locations. The present paper sets forth a new approach along the lines of welfare economics towards the end of determining the factors (such as demand, cost, welfare (or utility), etc.) which underscore public facility location patterns. In the process of developing our model, the approach is shown to dovetail with that applicable to locations of private enterprises. What in many respects is a general theory of facility location is thereby established herein.     

城市电力设施布局规划-变电站选址定容

随着城市发展日益加速,电力需求相应增长,对电力设施建设提出了新的需求,即由供电企业和规划部门联合开展城市电力设施布局规划.为解决电力设施布局规划中的变电站选址定容问题,通过建立变电站经济容量、经济供电半径和经济个数等相关数学指标模型,提出了一种基于变电站建设和运行费用最小为目标函数的变电站定容优化方法,提出了一种基于“覆盖圆”的变电站选址优化方法,并通过工程算例说明了选址定容优化方法的使用方法和和实用性.     

基于GIS-AHP的建筑废弃物消纳场选址优化研究——以广州市番禺区为例

随着我国城市化进程的加快,新建建筑和拆迁改造项目产生了巨量废弃物。如果建筑废弃物消纳场场址选择不当,就会对环境、社会和经济造成重大的影响。为此,结合AHP-Entropy方法,利用GIS技术,使用整数规划建立建筑废弃物物流回收网络,以广州市番禺区为例,构建选址优化模型,确定了番禺区内最适宜建设消纳场的位置。综合考虑了与消纳场建设和运营有关的各项成本,确定了消纳场的理想数量和建议容量。建筑废弃物消纳场属于邻避型设施,因此建设时要考虑当地居民对建设消纳场影响,研究结果可以为政府管理部门规划建筑废弃物物流管理链,以及为消纳场选址等方面提供参考。     

Exploring an integrated method for measuring the relative spatial equity in public facilities in the context of urban parks

This paper proposes a new integrated modeling framework that contributes to the evaluation of public facility distribution for spatial equity in urban development. The framework consists of two integrated models—accessibility and mobility—that, based on the gravity model, are integrated as a framework for measuring the relative spatial equities of urban public facilities. They are presented as geographic information system (GIS) and spatial analysis models. The models consider individual traffic behavioral abilities and simulate regional differences in the spatial equities of urban parks. The results show unequal regional spatial development that affects mismatches between urban park services. The accumulated travel time costs associated with different resident traffic mobility and urban park location types affect the access opportunities of residents. This integrated model could be a useful reference to help urban planners analyze, investigate, and adjust the distribution of public facilities in a more equitable manner.     

岩土工程中基于栅格的三维地层建模及空间分析

地理信息系统（GIS）及空间信息分析技术的发展为解决复杂的岩土工程科学问题提供新的手段,三维空间的地层和硐室建模是岩土工程GIS信息技术的核心内容。在此基础上,研究三维空间分析算法并实现具备强大面向对象分析功能的GIS信息系统,是该项技术在岩土工程领域得以推广应用的前提条件。以典型的工程应用实例为背景,介绍基于栅格的包含多元信息（监测设施、工程措施和地质断层等）的三维地层建模技术,详细探讨地层模型中的任意单纯地层剖面生成、地层与三维场景中的水位面及实体相交、地层与硐室的混合剖切算法及面积和体积的空间计算等分析功能。     

Is inequality in the distribution of urban facilities inequitable? Exploring a method for identifying spatial inequity in an Iranian city

Achieving spatial equity in the distribution of public facilities has been explored over the last two decades. The direction of these attempts was to offer an integrated index of spatial equity to decrease inequalities between cities. This study seeks to explore an integrated model for spatial inequity measurement (SIM), with a particular focus on inequalities resulting from a) mismatch of population demand (need) and population that can be supported by a facility; b) spatial mismatch of population distribution in relation to facility distribution; and c) mismatch of human deprivation in relation to spatially located “nonenjoyment.” The SIM was examined in 15 kinds of facilities together with different service areas in Hamadan city by integrating geographic information system (GIS) and spatial analysis models. This model identifies and calculates spatial inequities in all city units, in regard to whole facilities, distinct sets of facilities, or an individual facility; it then maps these facilities to determine the areas and the extent to which they experience inequity, for rational prioritization of the distribution of facilities in future planning. The results show that the majority of the city population experienced “nonenjoyment,” indicating a widespread spatial inequity among different groups of people. They also indicated the importance of public facilities in determining the level of inequalities and subsequent deprivation of the poor that can occur from inequitable spatial distribution. This model is an integrated spatial analytical tool that is capable of determining and mapping the level of spatial inequity of all facilities in a disaggregated and aggregated manner for an urban area.     

The fixed charge maximal covering location problem

The maximal covering location problem is based on locatingp facilities in such a manner that coverage is maximized within set distance or time standards. This problem has been extended in a number of different ways where the main theme still involves locating a fixed number of facilities. In many applications site costs are not equal; this should cast doubt on the use of a constraint that fixes the number of facilities at a given number as compared to an approach that minimizes site costs and maximizes coverage. This paper addresses the use of site costs in a maximal covering location problem and presents several approaches to solutions, along with computational results. Theoretical linkages to other location models are also presented.     

人群活动导向的老城区公服设施供给模式研究

在我国城镇化转向注重质量发展背景下,传统公服设施配置思路已难以适应居民多元化需求,尤其在用地紧张的老城区,公服设施需求与供给的矛盾十分突出。以广州越秀老城区为例,基于公服设施POI数据和步行轨迹大数据解析老城区现有公服设施存在问题,同时结合对越秀区梅花街道86位居民的访谈调研,以不同人群活动特征为出发点,通过测度设施布局与人群活动轨迹特征,提出有别于新区的老城公服设施优化策略。研究表明：现有相关设施配置标准更多是解决“有”与“无”的问题,而忽视设施实际设施使用效果;老城区设施规划应区别新区集中式设施服务中心,结合不同人群生活需求和出行特征,以点状分散、路径串联的模式优化设施布局,可以一定程度上改变老城区发展困境。     

Location strategy for a firm under competitive delivered prices

This paper addresses the location problem for an entering firm that will play a Bertrand game with other pre-existing firms in order to maximize its profit. Demand for a homogeneous product is price-sensitive and firms use delivered pricing. Under some specific conditions, it is shown that the aggregate profit of the pre-existing facilities increases as the number of facilities of the entrant increases. The problem is analyzed for a network and for a discrete location space, showing that in both cases it can be solved by a Mixed Integer Linear Programming (MILP) formulation. This formulation is used to solve an illustrative example in a variety of scenarios, where profits for both the entering firm and its competitors are analyzed. In some scenarios is seen that the aggregate profit of the pre-existing facilities increases in the number of facilities of the entrant. It is also shown that locations are stabler with respect to changes in number of new facilities than with respect to changes in demand function.     

Thep-median scheduling and location problem

With few exceptions, public-facility location models have considered facility accessibility to be solely a function of spatial distribution relative to demand. In this paper, we expand this definition to recognize a temporal component as well. A model is presented that optimally locates a given number of facilities and simultaneously schedules their operations to maximize accessibility to demand. In addition, for the special case when facilities already exist, a model is presented that focuses solely on the optimal scheduling of facility operations. Test results indicate that these models may have significant and varied implications for locational and policy analysis.An earlier version of this paper was presented at the 36th North American Meetings, Santa Barbara, November 1989.     

社区商业性生活街道老幼互动行为场景研究——三个广州案例实证

儿童友好社区和老年友好社区的发展理念已在国内试点城市推进实践,但社区建设中的老幼友好规划设计研究尚处于起步阶段。为探索社区生活街道如何为老幼人群提供接触他人、融入社区的良好支持,利用行为跟踪法和环境行为定点观察法,以广州的三个典型社区商业性生活街道为研究对象,对老幼群体在街道中的行为特征和互动场景模式进行分析与归纳,总结提出老幼人群互动的五种行为模式、典型街道生活场景模式和三种行为序列。从增进社区老幼互动、提升社区街道活力的角度,提出设施邻近和设施共享的社区生活设施复合布局模式构想。     

GIS in Seismic Evaluation of Essential Facilities

Abstract: This research used PC ARC/INFO, a geographic information system (GIS), to assess the potential seismic vulnerability of essential facilities in Memphis and Shelby County, Tennessee. The GIS is a powerful tool for spatial operations. It offers a link between spatial data in a computerized map form and related nonspatial attribute files. It has the ability to overlay, compare, and analyze several maps in digital form with speed and efficiency. In order to assess the potential vulnerability of essential facilities, evaluation criteria with rational weighting (including soil type, liquefaction potential, slope, foundation, structural conditions, and important elements of bridges such as detour length and average daily traffic) were identified. This research proved that GIS is a reliable and efficient tool for vulnerability assessment of essential facilities in an earthquake-prone area. The GIS is convenient and productive in data management. It is easy to produce special-purpose maps at selected scale and tabular analysis reports in desired format. Results of the study are important for future facility maintenance and improvement and earthquake preparedness /response planning.     

Social Infrastructure Planning: A Location Model and Solution Methods

Abstract:   This article deals with social infrastructure planning problems of the following type. Authorities want to determine where to locate the facilities of a social infrastructure network and what should be the capacity of these facilities. Each user must be assigned to its closest facility and, to be economically viable, each facility must serve at least a pre-specified level of demand. The objective is to maximize the accessibility to facilities (i.e., to minimize the distance traveled by users to reach the facilities). A location model that captures the above features is formulated and different solution methods are tested. Among the methods tested, tabu search and a specialized local search heuristic provided the best solutions. The application of the model is illustrated through a case study involving the location of preschools in the municipality of Miranda do Corvo, Portugal.     

嘉兴地区城乡统筹与市域规划研究--以嘉兴地区为例

在分析了快速城市化地区城乡空间格局所发生的深刻变化以及现有规划体系所面临的主要问题后,介绍了浙江省嘉兴市编制的市域总体规划的主要内容.通过GIS技术摸清市域空间资源总量,在满足区域生态环境需要的前提下,统筹市域空间资源的保护和利用,合理确定嘉兴网络型组合城市的空间架构与功能布局,统筹协调基础设施及社会设施,加强市域空间管治与协调.     

养老设施室外环境中4类重要空间的适老化设计——基于使用者的活动及需求

【目的】近年来,中国人口老龄化程度不断加深且养老设施数量显著增加,然而养老设施室外环境设计往往忽略了使用者的真实需求,对养老设施室外环境展开深入研究具有很强的现实需求和紧迫性。【方法/过程】通过对国内外养老设施的实地调研,以及对设施内老年人、运营人员及来访亲友的深入访谈,了解其使用需求和对现有室外空间环境的评价,列举并总结出4类重要空间（集体活动广场、楼前活动场地、代际交流活动场地、认知症花园）主要使用者（老年人、护理人员）的活动特点及需求,并以此为出发点对空间设计中常见的问题进行分析。【结果/结论】结合实例,从运营实践和设计优化的角度对中国养老设施室外空间适老化环境建设中存在的问题进行研究探讨,针对4类重要空间提出具有可操作性的适老化设计要点,以期为未来养老设施项目的适老化设计提供指导,并为相关行业标准的制定提供参考。     

A user-centric space heating energy management framework for multi-family residential facilities based on occupant pattern prediction modeling

Space heating is the highest energy consumer in the operation of residential facilities in cold regions. Energy saving measures for efficient space heating operation are thus of paramount importance in efforts to reduce energy consumption in buildings. For effective functioning of space heating systems, efficient facility management coupled with relevant occupant behaviour information is necessary. However, current practice in space heating control is event-driven rather than user-centric, and in most cases relevant occupant information is not incorporated into space heating energy management strategies. This causes system inefficiency during the occupancy phase. For multi-family residential facilities, integrating occupant information within space heating energy management strategies poses several challenges; unlike with commercial facilities, in multi-family facilities occupant behavior does not follow any fixed activity-schedule pattern. In this study, a framework is developed for extracting relevant information about the uncertainties pertaining to occupant patterns (i.e., demand load) in multi-family residential facilities by identifying the factors affecting space heating energy consumption. This is achieved using sensor-based data monitoring during the occupancy phase. Based on the analysis of the monitoring data, a structure is defined for developing an occupant pattern prediction model that can be integrated with energy management strategies to reduce energy usage in multi-family residential facilities. To demonstrate the developed framework, a multi-family residential building in Fort McMurray, Canada, is chosen as a case study. This paper shows that integrating the developed occupant pattern prediction model within space heating energy management strategies can assist facility managers to achieve space heating energy savings in multi-family residential facilities.