Location Of Service Centers Research Articles

Public service system design with fuzzy parameters of perceived utility

Public service systems are designed to satisfy a public demand on some service. The public is represented here by individual users concentrated at dwelling places situated in a served geographical area. The structure of a public service system is determined by a given number of service center locations, which are to be selected from a finite set of possible locations so that utility perceived by the users be maximal. In this paper, we propose an approach to the public service system design, where the utility perceived by an individual user depends on uncertain parameters. The uncertainty is handled using the theory of fuzzy sets in connection with integer programming tools. The suggested way of public service system designing is accompanied by a computational study.

Optimum Allocation of Centers in Geographical Information System by Means of Fuzzy Interval Graph Bases

In this paper the problem of optimal location of service centers is considered by minimax criterion. It is supposed that the information received from GIS is presented like graph with fuzzy intervals. The notion of fuzzy set of interval bases is considered. It is shown that the problem of service centers location is reduced to a problem of finding fuzzy set of interval bases. Method of finding fuzzy interval bases which is generalization of Maghout method for fuzzy graphs is suggested to use. In addition method of calculation of membership function of fuzzy intervals is proposed.

Solving a Bicriteria Problem of Optimal Service Centers Location

The problem of service centers location is formulated as a bicriteria optimization problem of finding a dominating set in graph. We investigate the properties of this problem and propose the methods for its solving. The results of computational experiment for instances with random data are presented.

Location of Multiple-Server Common Service Centers or Facilities, for Minimizing General Congestion and Travel Cost Functions

The authors propose a model for locating a fixed number of multiple-server service centers or facilities that may become congested. Customers arriving at these centers must wait in line until served. The locations of the facilities and the allocations of customers to them are chosen by the planner, so to minimize both travel costs and system-wide congestion (or queuing) at centers. All the customers arriving at the facilities must be served, up to a certain maximum line length. The travel cost in which customers incur is a function of the length of the trip to the facility, while the congestion cost at a facility is a general function of the number of customers waiting on line or being served at the facility. The resulting model is a nonlinear p-median formulation. A solution method for this nonlinear model is proposed, and computational experience is presented.

Location of Multiple Server Common Service Centers or Public Facilities for Minimizing General Congestion and Travel Cost Functions

We propose a model and solution methods, for locating a fixed number of multiple-server, congestible common service centers or congestible public facilities. Locations are chosen so to minimize consumers' congestion (or queuing) and travel costs, considering that all the demand must be served. Customers choose the facilities to which they travel in order to receive service at minimum travel and congestion cost. As a proxy for this criterion, total travel and waiting costs are minimized. The travel cost is a general function of the origin and destination of the demand, while the congestion cost is a general function of the number of customers in queue at the facilities.

A two‐echelon inventory‐location problem with service considerations

AbstractWe study the problem of designing a two‐echelon spare parts inventory system consisting of a central plant and a number of service centers each serving a set of customers with stochastic demand. Processing and storage capacities at both levels of facilities are limited. The manufacturing process is modeled as a queuing system at the plant. The goal is to optimize the base‐stock levels at both echelons, the location of service centers, and the allocation of customers to centers simultaneously, subject to service constraints. A mixed integer nonlinear programming model (MINLP) is formulated to minimize the total expected cost of the system. The problem is NP‐hard and a Lagrangian heuristic is proposed. We present computational results and discuss the trade‐off between cost and service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009

Knowledge and practice of cervical cancer screening among female professional health workers in a sub-urban district of Nigeria

Cervical cancer is the commonest genital tract malignancies in the females and its burden is enormous, to the patient and her community. It is largely preventable or curable when detected at the very early stage through effective screening programme. Very poor clients' attendance has been noticed at the services provided by the state and other health institutions and female health workers are not exemptions. To determine the level of knowledge of female health workers about cervical cancer prevention using Pap smear and cytology, the degree of utilization and factors that may prevent utilization of services. It is a questionnaire based cross-sectional survey of 187 female health workers in Remo district of Ogun State, assessing their knowledge and utilization of cervical cancer screening services. There were 187 respondents, 78.3% were found to have knowledge of Papanicolaou smear (Pap smear) and only 16 (8.7%) had utilized the services. Lack of physicians' referrals and ignorance about location of service centers were the two most frequent reasons for failure of utilization. Socio-demographic factors do not influence utilization. There is a need for a more expanded and community oriented screening programme that will target the male population with regards to their consent and support. Health care providers should improve on opportunistic screening of patients and adopt alternative screening techniques, such as visual inspection with acetic acid (VIA), so as to widen patients coverage. Continuous education of female health workers about cancer of the cervix and its prevention will improve knowledge and increase service utilization. Nigerian Medical Practitioner Vol. 50(1) 2006: 19-22

A BICRITERIA PROBLEM OF OPTIMAL SERVICE CENTERS LOCATION

The problem of service centers location is formulated as a bicriteria optimization problem of finding a dominating set in graph. We investigate the properties of this problem and propose the methods for its solving. The results of computer experiment for instances with random data are presented.

Agent-based and analytical modeling to evaluate the effectiveness of greenbelts

We present several models of residential development at the rural–urban fringe to evaluate the effectiveness of a greenbelt located beside a developed area, for delaying development outside the greenbelt. First, we develop a mathematical model, under two assumptions about the distributions of service centers, that represents the trade-off between greenbelt placement and width, their effects on the rate of development beyond the greenbelt, and how these interact with spatial patterns of aesthetic quality and the locations of services. Next, we present three agent-based models (ABMs) that include agents with the potential for heterogeneous preferences and a landscape with the potential for heterogeneous attributes. Results from experiments run with a one-dimensional ABM agree with the starkest of the results from the mathematical model, strengthening the support for both models. Further, we present two different two-dimensional ABMs and conduct a series of experiments to supplement our mathematical analysis. These include examining the effects of heterogeneous agent preferences, multiple landscape patterns, incomplete or imperfect information available to agents, and a positive aesthetic quality impact of the greenbelt on neighboring locations. These results suggest how width and location of the greenbelt could help determine the effectiveness of greenbelts for slowing sprawl, but that these relationships are sensitive to the patterns of landscape aesthetic quality and assumptions about service center locations.

Changing Location and Service Area of Day Service Centers after the Introduction of the Long-term Care Insurance System

After the introduction of the long-term care insurance system in April 2000, the utilization of welfare facilities for the elderly has changed. The use of day service centers is possibly the biggest change brought about by the long-term care insurance system. The effect of the measures adopted by the administration has especially influenced the location of facilities used before the start of the new long-term care insurance system. However, after the institutionalization of the long-term care insurance system, it became possible for users to select a facility freely. This paper clarifies the changing location and service area of day service centers after the inception of the long-term care insurance system. This was difficult using conventional methods applicable to the municipality level since the service area of the centers occupies only a small part of the city, the residence wards. After the long-term care insurance system began operation, the number of private facilities with small capacity increased. The service area of day service centers changed mainly to the extent that the facilities expanded. As a result, competition is occurring among the day service centers at the residence ward level, and the era of free competition has arrived even in the welfare-related industry in Japan.

ATLANTA IN THE TELECOMMUNICATIONS AGE: THE FIBER-OPTIC INFORMATION NETWORK

This paper addresses the role of the Atlanta metropolitan area as a telecommunications center based on the use of fiber optics. The major focus is on the intrametropolitan layout of this network, including fiber-optic access points, downtown and suburban fiber loops, and the location of data service and teleservice centers. The aim is to identify congruence between high-technology firms and fiber-optic lines that produce clustering within the metropolitan region. Atlanta has a dense fiber-optic infrastructure in place in the CBD-Midtown area and in several corporate clusters in the suburbs. A number of fiber-optic carriers compete in the Atlanta market—including BellSouth, with approximately 400,000 miles of fiber-optic cable—giving Atlanta more miles of optic fiber than any other metropolitan area in the United States. This extensive fiber network bestows fresh advantages to old downtown property and businesses and creates burgeoning opportunities in the suburbs as it literally undergirds the growth of edge cities at such locations as Perimeter Center and Cumberland-Galleria. Long-established Atlanta firms such as Coca-Cola have drawn fiber sites to themselves, whereas sites on fiber-optic loops attract new businesses seeking ready backbone and broadband access to other metropolitan areas in the United States and cities around the globe. This study also focuses on Atlanta's position within the U.S. intermetropolitan telecommunications hierarchy, where the metropolitan area ranks sixth in total number of backbone connections with other U.S. Metropolitan areas. [Key words: Atlanta, fiber optics, telecommunications.]

Probabilistic, Maximal Covering Location—Allocation Models forCongested Systems

When dealing with the design of service networks, such as health andemergency medical services, banking or distributed ticket‐selling services, the location of servicecenters has a strong influence on the congestion at each of them, and, consequently, on thequality of service. In this paper, several probabilistic maximal coveringlocation—allocation models with constrained waiting time for queue length are presentedto consider service congestion. The first model considers the location of a given number ofsingle‐server centers such that the maximum population is served within a standard distance, andnobody stands in line for longer than a given time or with more than a predetermined number ofother users. Several maximal coverage models are then formulated with one or more servers perservice center. A new heuristic is developed to solve the models and tested in a 30‐node network.

Best location of service centers in a treelike network under budget constraints

We consider the problem of locating service centers in a treelike network in order to maximize the serviced population under budget constraints. We show that the problem is NP-hard. In the case where the costs of establishing the service centers are equal for all n cities we obtain the maximum weight k-domination problem. An O( nk 2) dynamic programming procedure is given. Then an O( nB 2) pseudo-polynomial dynamic programming procedure is presented for the original problem, where B is the budget constraint. Finally a variation of the new left-right dynamic programming technique is applied to obtain a more efficient pseudo-polynomial procedure.

Positioning of Emergency Facilities in an Obstructed Traffic Grid

We developed algorithms to determine the optimal location of emergency service centers in a given city. We give consideration both to the peculiarities of a particular town, Rio Rancho, and to the procedure by which problems of this nature can be solved in general. The streets of Rio Ranch0 are laid out in a uniform grid, except for two obstacles through which there are no streets. We are given data for the demand for emergency service at each block in the grid. We developed algorithms to find the transit times between any two points on the grid for Rio Rancho. To do this. we calculated a distance on a grid with no obstacles, then adjusted for the particular obstructions. We first assumed that demand was concentrated at the center of each block and that stations were located at street intersections. Under these assumptions, the problem is amenable to an exhaustive trial of all possibilities. We then made the more sophisticated assumption that the distribution of demand is continuous, and that the emergency facilities could be located anywhere on the streets. We prove two results which greatly reduce this problem: (I) it is necessary that the location of such emergency statton be at an intersection; and (2) it is an equivalent problem to consider the demand to be located discretely at the center of each block, rather than being continuously distributed over the block. Due to these results, it is possible to run an exhaustive case study in this case as well. Statistical distributions were calculated to provide a means of comparison of the optimal result with the average result. We studied the stability of the solution with respect to the demand distribution and obstacle configuration and found it to be very stable in the first case, and reasonably stable in the latter. Finally, we discuss how similar problems would be approached, and in particular, how an approximation scheme could be implemented if the large number of possibilities prohibits an exhaustive analysis. RESTATEMENT OF THE PROBLEM The township of Rio Ranch0 has hitherto not had its own emergency facilities. It has secured funds to erect two emergency facilities in 1986, each of which will combine ambulance, fire. and police facilities. Figure I indicates the demand, or number of emergencies per square block for 1985. The “L” region in the north is an obstacle, while the rectangle to the south is a park with a shallow pond. It takes an emergency vehicle an average of 15 set to go one block in the N-S direction and 20 set in the E-W direction. Our task is to locate the two facilities so as to minimize the total response time. GENERAL ASSUMPTIONS We modelled an urban traffic grid with two obstructions. We made the following assumptions: 61 I

A Systematic Approach for Identifying Planning Zones and Service Centers: A Nevada State Health Example

This study offers a methodology to help identify the best service center locations and boundaries in order to increase economic efficiency in providing many community services. The procedures are illustrated with an application to health planning in the state of Nevada. A computer program that minimizes travel distances of potential health center users, for a given number of service centers, is used to identify optimal service center locations. Factor analysis is used to identify adjacent counties which are similar in a number of health related characteristics. The research illustrates a methodology which has potential application for other services and situations.

Positioning of emergency facilities in an obstructed traffic grid

We developed algorithms to determine the optimal location of emergency service centers in a given city. We give consideration both to the peculiarities of a particular town, Rio Rancho, and to the procedure by which problems of this nature can be solved in general. The streets of Rio Rancho are laid out in a uniform grid, except for two obstacles through which there are no streets. We are given data for the demand for emergency service at each block in the grid. We developed algorithms to find the transit times between any two points on the grid for Rio Rancho. To do this, we calculated a distance on a grid with no obstacles, then adjusted for the particular obstructions. We first assumed that demand was concentrated at the center of each block and that stations were located at street intersections. Under these assumptions, the problem is amenable to an exhaustive trial of all possibilities. We then made the more sophisticated assumption that the distribution of demand is continuous, and that the emergency facilities could be located anywhere on the streets. We prove two results which greatly reduce this problem: (1) it is necessary that the location of such emergency station be at an intersection; and (2) it is an equivalent problem to consider the demand to be located discretely at the center of each block, rather than being continuously distributed over the block. Due to these results, it is possible to run an exhaustive case study in this case as well. Statistical distributions were calculated to provide a means of comparison of the optimal result with the average result. We studied the stability of the solution with respect to the demand distribution and obstacle configuration and found it to be very stable in the first case, and reasonably stable in the latter. Finally, we discuss how similar problems would be approached, and in particular, how an approximation scheme could be implemented if the large number of possibilities prohibits an exhaustive analysis.

Toward a more flexible equilibrium theory of service center location and development

Toward a more flexible equilibrium theory of service center location and development