• 정보기술과데이타베이스저널
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• 제7권2호
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• pp.47-59
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• 2000

In this paper, we analyze the applicability of a general optimization algorithm to a database optimization problem. The index selection problem Is the problem to choose a set of indexes for a database in a way that the cost to process queries in the given workload is minimized subject to a given storage space restriction for storing indexes. The problem is well known in database research fields, and many optimization and/or heuristic algorithms have been proposed. Our work differs from previous research in that we formalize the problem in the form of non-linear Integer Programming model, and investigate the feasibility and applicability of a general purpose optimization algorithm, called OPBDP, through experiments. We implemented algorithms to generate workload data sets and problem instances for the experiment. The OPBDP algorithm, which is a non-linear 0-1 Integer Programming problem solver based on Davis-Putnam method, worked generally well for our problem formulation. The experiment result showed various performance characteristics depending on the types of decision variables, variable navigation methods and ocher algorithm parameters, and indicates the need of further study on the exploitation of the general purpose optimization techniques for the optimization problems in database area.

• 산업경영시스템학회지
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• 제45권4호
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• pp.134-141
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• 2022

Transportation in urban area has been getting hard to fulfill the demand on time. There are various uncertainties and obstacles related with road conditions, traffic congestions, and accidents to interrupt the on-time deliveries. With this situation, the last mile logistics has been a keen issue for researchers and practitioners to find the best strategy of the problem. A way to resolve the problem is to use parcel lockers. Parcel locker is a storage that customers can pick up their products. Transportation vehicles deliver the products to parcel lockers instead of all customer sites. Using the parcel lockers, the total delivery costs can be reduced. However, the inconvenience of customer has to increase. Thus, we have to optimal solution to balance between the total delivery costs and customers' inconvenience. This paper formulates a mathematical model to find the optimal solution for the vehicle routing problem and the location problem of parcel lockers. Experimental results provide the viability to find optimal strategy for the routing problem as well as the location problem.

• 산업경영시스템학회지
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• 제47권2호
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• pp.168-175
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• 2024

Due to the complexity of urban area, the city vehicle routing problem has been a difficult problem. The problem has involved factors such as parking availability, road conditions, and traffic congestion, all of which increase transportation costs and delivery times. To resolve this problem, one effective solution can be the use of parcel lockers located near customer sites, where products are stored for customers to pick up. When a vehicle delivers products to a designated parcel locker, customers in the vicinity must pick up their products from that locker. Recently, identifying optimal locations for these parcel lockers has become an important research issue. This paper addresses the parcel locker location problem within the context of urban traffic congestion. By considering dynamic environmental factors, we propose a Markov decision process model to tackle the city vehicle routing problem. To ensure more real situations, we have used optimal paths for distances between two nodes. Numerical results demonstrate the viability of our model and solution strategy.

• 가정과삶의질연구
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• 제16권3호
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• pp.123-140
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• 1998

The purpose of this study was to investigate the consistency of socially responsible consumer attitudes and behaviors toward environment problem. The major findings were as follows; 1. The socially responsible consumer behaviors toward environment problem were classified into resource conservation purchasing & using in green product and recycling behavior by factor analysis. 2. Correlation coefficient of the socially responsible attitudes and behaviors toward environment problem was found to be above. 43. This result implies that the consistency of socially responsible attitudes and behaviors was very high. 3. In the area of total socially responsible consumer attitudes and behaviors toward environment problem the related variable on the consistency of attitude and behavior were altruism perceived power of big business liberalism alienation dogmatism perceived consumer effectiveness faith on the environmental regulation policy experience of environment education and consumer i formation.

• 대한가정학회지
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• 제33권1호
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• pp.19-32
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• 1995

The purpose of this study is to investigate the consumer safety problems appeared in the Korean mass media-the newspaper(the Kong-A Ilbo and the Chosun Ilbo) and the consumer magazines(the Sobija-Sidae and the Sobija) from 1991 to 1993. I use the content analysis of the articles related with consumer safety through the above mass media. The results are (1) the goods-services areas that are severe in the consumer safety problem are food, environment, medicine, electric appliances, services(restaurant, medical service), and etc. (2) the most important problem areas are Toxic ingredients(remaining agricultural chemicals and heavy metal), Food additionals, Sanitary problem, Hygiene products hazard, Safety accident, Environmental pollution, etc. (3) the goods-service area and the consumer safety problem are different according to the publication year and the mass media type.

• 한국경영과학회지
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• 제35권1호
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• pp.111-124
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• 2010

In the last decade, traveling purchaser problem (TPP) has received some attention of the researchers in the operational research area. TPP is a generalization of the well-known traveling salesman problem (TSP), which has many real-world applications such as purchasing the required raw materials for the manufacturing factories and the scheduling of a set of jobs over some machines, and many others. In this paper we suggest heterogeneous multiple traveling purchaser problem with budget constraint (HMTPP-B) which looks for several cycles starting at and ending to the depot and visiting a subset at a minimum traveling cost and such that the demand for each product is satisfied and the cost spent for purchasing the products does not exceed a given budget threshold. All the past studies of TPP are restricted on a single purchaser. Therefore we randomly generated some instances. CPLEX is used for getting optimal solutions in these experiments.

• 정보처리학회논문지A
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• 제18A권2호
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• pp.69-74
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• 2011

그래프 G의 최소 dominating set 문제는 G의 dominating set들 중 가장 작은 크기의 dominating set을 찾는 문제이며, NP-complete class에 속해 polynomial time안에 해결할 수 없는 문제로 잘 알려져 있다. 그러나, heuristic한 방법 혹은 approximation 방법을 이용해 특정한 분야에 적용이 가능하다. 본 논문에서는 세 개의 서로 다른 simulated annealing 알고리즘을 제시하여, 이들 알고리즘을 DIMACS에서 제시한 그래프들에 적용한 경우 효율성 증가가 이루어지는 것을 실험적으로 보이고자 한다.

• 대한산업공학회지
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• 제37권3호
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• pp.171-179
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• 2011

In this paper, we deal with the vehicle routing problem that could establish operational plan of military engineer for survivability support of artillery position construction. We propose VRPTW(vehicle routing problem with time-window) model of special form that considered service level to reflect the characteristics of military operations rather than the logic of economic efficiencies in the objective function. Furthermore we suggest modified particle swarm optimization algorithm for service based vehicle routing problem solution that can be possible to search in complicated and uncertain area and control relation softly between global and local search.

• 한국환경교육학회지:환경교육
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• 제20권1호
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• pp.118-130
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• 2007

This article investigated the effects of students' knowledge, beliefs, and attitudes about environment on environmental issue-based environmental problem solving in secondary school students. This article also investigated whether these factors are related to the environmental problem solving. Therefore, we first developed the test instruments to measure secondary school students' environmental knowledge, environmental beliefs, and environmental attitudes. Then, we developed the environmental issue-based teaching materials for secondary school students. The subjects participated in a environmental issue-based approach that consist of 3 lesson over an three weeks period. The results of this study presents that environmental knowledge and environmental beliefs are effective for the environmental problem solving in middle school environment class. First, secondary school students knew well ecological knowledge about environmental problem, and was entertaining most ecological beliefs. Second, secondary school students were having attitude which is most pro-environmental behaviors. Third, secondary school students are referring necessity of development partially about environment point at issue of country level. But, they were retaining situation of preservation about environment point at issue of area level. It's not easy to generalize these results because of many different variables, but the results suggests that teachers should make an effort to improve student's environmental problem solving ability applying environmental issue-based learning. And it's necessary to develop many kinds of environmental issues and teacher's instruction method to enrich problem solving ability in the process of environmental issue-based learning.

• 산업경영시스템학회지
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• 제45권4호
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• pp.217-224
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• 2022

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.