• Industrial Engineering and Management Systems
• /
• v.11 no.2
• /
• pp.202-214
• /
• 2012

This paper discusses the problem of determining locations for public health-care facilities and allocating patients to the public facilities with the objective of minimizing the total construction cost. The public health-care facilities have two types of facilities: public hospitals and health centers. The public hospital provides both hospital services and homecare services, while the health center provides only homecare service. We present an integer programming formulation for the problem, and develop two types of heuristics, based on priority rules and approximate mathematical formulation. Results of a series of computational experiments on a number of problem instances show that the algorithms give good solutions in a reasonable computation time.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2007.11a
• /
• pp.316-321
• /
• 2007

The hierarchical covering location problem emphasizes the issue of locating of hierarchical facilities in order to maximize the number of customers that can be covered. In the classical HCLP(Hierarchical Covering Location Problem), it is assumed that the customers are covered completely if they are located within a specific distance from the facility, and not covered otherwise. The generalized HCLP is introduced that the coverage of customers is measured to be any real value rather than 0 or 1, where the service level may decrease according to the distance. Mixed integer programming formulation for the generalized HCLP is suggested with a partial coverage of service. Solutions are found using OPL Studio, and are evaluated for various cases.

• Korean Management Science Review
• /
• v.29 no.2
• /
• pp.21-34
• /
• 2012

This paper addresses a network design problem in a supply chain system that involves locating both plants and distribution centers, and determining the best strategy for distributing products from the suppliers to the plants, from the plants to the distribution centers and from the distribution centers to the customers. This paper suggests a cooperative coevolutionary algorithm (CCEA) approach to solve the model. First, the problem is decomposed into three subproblems for each of which the chromosome population is created correspondingly. Each chromosome in each population is represented as a permutation denoting the priority. Then an algorithm generating a solution from the combined set of chromosomes from each population is suggested. Also an algorithm evaluating the performance of a solution is suggested. An experimental study is carried out. The results show that our CCEA tends to generate better solutions than the previous CCEA as the problem size gets larger and that the permutation representation for chromosome used here is better than other representation.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.1
• /
• pp.8-17
• /
• 2005

As power system is developed, an expansion of power equipments is very necessary to the stability of power system and the problem of locating the facilities on downtown is more serious. At this time introduction of superconducting devices are very good alternative to solve the problem. This study describes cases possible to apply HTS cable to Korean power system and analyzes the power system with HTS cable. First of all, we determine the case that HTS cable can be applied to KEPCO systems and analyze the static state of power system. Then we propose a solution of the problem resulting from the analysis.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.18 no.1
• /
• pp.97-117
• /
• 1993

This paper considers inspection station location problem for a flexible assembly line that consists of multiple stages. By considering the trade-off between locating an station at an "early" stage and at a "late" stage, we have developed some dominance relations on a graph. Based on the dominance relations, we then present an algorithm that finds an optimal inspection plan and a heuristic approach that finds a near-optimal inspection plan. The effectiveness of these two algorithms is demonstrated by two numerical examples. numerical examples.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.602-605
• /
• 2006

Locating reinforcing bars, in particular to know their accurate depths and horizontal distances, is very important in radar inspection of concrete structures. By the way, it is not easy for an accurate depth and horizontal distance estimation of reinforcing bars in concrete structures by the radar test. This problem can be solved by synthetic aperture radar method. To improve the vertical and horizontal resolution of reinforcing bars in concrete, synthetic aperture radar method was examined in this study.

• Journal of the Korean Mathematical Society
• /
• v.56 no.6
• /
• pp.1515-1528
• /
• 2019

We show that large subsets of vector spaces over finite fields determine certain point configurations with prescribed distance structure. More specifically, we consider the complete graph with vertices as the points of $A{\subseteq}F^d_q$ and edges assigned the algebraic distance between pairs of vertices. We prove nontrivial results on locating specified subgraphs of maximum vertex degree at most t in dimensions $d{\geq}2t$.

• Korean Journal of Mathematics
• /
• v.30 no.3
• /
• pp.503-512
• /
• 2022

In this paper, we are concerned with the problem of locating the zeros of regular polynomials of a quaternionic variable with quaternionic coefficients. We derive new bounds of Eneström-Kakeya type for the zeros of these polynomials by virtue of a maximum modulus theorem and the structure of the zero sets in the newly developed theory of regular functions and polynomials of a quaternionic variable. Our results generalize some recently proved results about the distribution of zeros of a quaternionic polynomial.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.1
• /
• pp.45-49
• /
• 2010

RTLS (Real Time Locating Systems) are used to track and identify the location of objects in real time. RTLS generally consist of tags, readers and engine etc. and applied in various environments. One problem encountered in RTLS is constraints for setting up readers according to environments. In these challenging environments, it is necessary to develop techniques that can use mobile readers. As mobile reader increase, whole reader increase. And it is necessary to develop technique that can select useful readers. Selected readers including mobile readers take effect performance of RTLS. This paper introduces the technique for selecting good readers using the convex hull algorithm. The result show the good performance which based on tag's location error and reduce the networking overhead.

• Journal of Korean Institute of Industrial Engineers
• /
• v.37 no.1
• /
• pp.19-29
• /
• 2011

Cellular network is comprised of several base stations which serve cellular shaped service area and each base station (BS) is connected to the mobile switching center (MSC). In this paper, the configuration modeling and algorithm of a cellular mobile network with the aim of minimizing the overall cost of operation (handover) and network installation cost (cabling cost and installing cost of mobile switching center) are considered. Handover and cabling cost is one of the key considerations in designing cellular telecommunication networks. For real-world applications, this configuration study covers in an integrated framework for two major decisions: locating MSC and assigning BS to MSC. The problem is expressed in an integer programming model and a heuristic algorithm based on Lagrangian relaxation is proposed to resolve the problem. Searching for the optimum solution through exact algorithm to this problem appears to be unrealistic considering the large scale nature and NP-Completeness of the problem. The suggested algorithm computes both the bound for the objective value of the problem and the feasible solution for the problem. A Lagrangian heuristics is developed to find the feasible solution. Numerical tests are performed for the effectiveness and efficiency of the proposed heuristic algorithm. Computational experiments show that the performance of the proposed heuristics is satisfactory in the quality of the generated solution.