• Industrial Engineering and Management Systems
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• 제8권1호
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• pp.14-21
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• 2009

We formulate a mathematical model of remanufacturing system as multi-stage reverse Logistics Network Problem (mrLNP) with minimizing the total costs for reverse logistics shipping cost and inventory holding cost at disassembly centers and processing centers over finite planning horizons. For solving this problem, in the 1st and the 2nd stages, we propose a Genetic Algorithm (GA) with priority-based encoding method combined with a new crossover operator called as Weight Mapping Crossover (WMX). A heuristic approach is applied in the 3rd stage where parts are transported from some processing centers to one manufacturer. Computer simulations show the effectiveness and efficiency of our approach. In numerical experiments, the results of the proposed method are better than pnGA (Prufer number-based GA).

• 산업경영시스템학회지
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• 제11권17호
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• pp.47-54
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• 1988

Korean National Railroad(K.N.R) playing a important role in land transportation gives us many problems to solve considering proper management of National Budget and development of the state of operation by maintaining train parts rationally as public services. According this study is to show inventory provision system for deciding the safety inventory level as the better rational method. Bibliography for this study is limited to only three kinds of seven brakes-shoe which is produced by T workshop in Korean National Railroad. To reduce the holding cost coming from the want of the stock and shortage cost of the stock expected. This study is to present a ratio of shortage on the stock permitted for the last definite period and the demand result forecast per month.

• 대한산업공학회지
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• 제16권1호
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• pp.51-58
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• 1990

A deterministic capacity expansion planning model for a two-capacity type facility is analyzed to determine the sizes to be expanded in each period so as to supply the known demands for two distinct capacity type(product) on time and to minimize the total cost incurred over a finite planning horizon of T periods. The model assumes that capacity unit of the facility simultaneously serves a prespecified number of demand units of each capacity type, that capacity type 1 can be used to supply demands for capacity type 2, but that capacity type 2 can't be used to supply demands for capacity type 1. Capacity expansion and excess capacity holding cost functions considered are nondecreasing and concave. The structure of an optimal solution is characterized and then used in developing an efficient dynamic programming algorithm that finds optimal capacity planning policy.

• 한국실내디자인학회논문집
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• 제22권5호
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• pp.60-67
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• 2013

Preference studies regarding the elderly housing have been conducted to find out design features in specific needs of certain elderly groups with their various demographic characteristics. The purpose of this study was to investigate preference for accessible design features for the elderly and find out the differences in preference whether the cost information was given or not. Contrast to the previous studies, we suggested some alternatives to fulfill the accessible goals. Preference for each option was investigated and differences in preference with its cost information was also investigated. The total of 700 questionnaires were collected and analyzed using SPSS 18.0. As a result, to remove the level differences, respondents prefer installation of trench to installation of deck or ramp. When people received the cost information, the proportion of selection for each option has slightly changed. The findings of the study suggest that cost information is an important factor for choosing the option for removal of level difference, installation of sink design and holding bars, and installation of elevator. Regardless of age, the respondents prefer sliding door option (its cost is equal to the other option), one of the door option for bath room. It may be due to the relative small area for its installation. It was found that when people recognized the importance of the accessible design features higher, they are ore likely to pay for the option even though its cost is higher. The higher people evaluate the importance of accessible design features, the more they can pay for the option. In general, for the preference of alternatives, there are significant differences between the elderly and the younger.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.904-913
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• 2005

This paper deals with an integrated problem of inventory control and dynamic pricing strategies for a commodity with price and sales-period dependent demand pattern, where a seller and customers have complete information of each other. The problem consists of two parts; one is each buyer's benefit problem which makes the best decision on price and time for buyer to purchase items, and the other one is a seller's profit problem which decides an optimal sales strategy concerned with inventory control and discount schedule. The seller's profit function consists of sales revenue and inventory holding cost functions. The two parts are closely related into each other with some related variables, so that any existing general solution methods can not be applied. Therefore, a simplified model with single seller and two customers in considered first, where demand for multiple units is allowed to each customer within a time limit. Therewith, the model is generalized for a n-customer-classes problem. To solve the proposed n-customer-set problem, a dynamic programming algorithm is derived. In the proposed dynamic programming algorithm, an intermediate profit function is used, which is computed in case of a fixed initial inventory level and then adjusted in searching for an optimal inventory level. This leads to an optimal sales strategy for a seller, which can derive an optimal decision on both an initial inventory level and a discount schedule, in $O(n^2)$ time. This result can be used for some extended problems with a small customer set and a short selling period, including sales strategy for department stores, Dutch auction for items with heavy holding cost, open tender of materials, quantity-limited sales, and cooperative buying in the on/off markets.

• International Journal of Industrial Entomology and Biomaterials
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• 제33권1호
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• pp.15-23
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• 2016

One major constraint in the development and implementation of a successful and cost-effective area-wide integrated pest management (AW-IPM) programme with a SIT component for Bactrocera oleae (Diptera: Tephritidae) is the ability to produce a large number of high quality mass-reared individuals. The aim of this study was to develop a more efficient and practical egg collection system in an attempt to improve the mass-rearing of this species. The following basic parameters were examined: egg production per female, egg hatch, pupal recovery, pupal weight, adult emergence and percentage of fliers. Three different strains (Israel wild-type, France wild-type, and Greece laboratory) were tested and each strain was evaluated for six generations. Female flies of the Israel strain produced significantly more eggs per female than the other two strains, but egg hatch was significantly lower. Egg hatch of the France wild type and the Greece laboratory strain was similar. For all other parameters, there was no significant difference between strains; however, there was a significant generational effect for all parameters observed. As a result of this study, a protocol was developed for the mass-rearing of this species that included the use of large adult holding cages that could house up to 96,000 flies per cage. The newly developed method of egg collection using a flat wax panel as one of the sides of an adult holding cage proved to be cost-effective, efficient, making colony growth easier for industrial mass-rearing.

• Journal of East Asia Management
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• 제4권1호
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• pp.53-77
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• 2023

Modern company faces an uncertain future and a competitive environment and are seeking new technologies and creative products to ensure the corporate growth and survival in the market through continuous innovation. "University Industry Cooperation(UIC)" is a point of contact for overcoming the crisis faced by companies and universities in this era and a cooperation platform for mutual prosperity. As a subsidiary of a university, "Technology Holding Company(THC)" is attracting attention as a new window for UIC in Korea. The role of THC is to establish and foster the business opportunities of their subsidiaries and to return investment profits to the university ecosystem again. But recently, the life cycle of technology is getting shorter, and the development cost is steadily increasing. In particular, with the increase of hybrid projects based on convergence and combination, the risk of conducting research(R&D) and new product development(NPD) projects is gradually increasing. A PMO refers to a project management organization that can contribute to improving the success rate of projects with increasing uncertainty by supporting project visibility and appropriate decision-making. The purpose of this study is to raise a research question on whether THC's corporate performance can be improved when "Project Management System(PMO Service)" is introduced into the subsidiary incubation system of THC. This study proposes several research methods to identify the relationship between the introduction of PMO and the corporate performance of THC.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술.기술논문발표회
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• pp.21-25
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• 2004

The column for Steel Framed Reinforced Concrete Structure (SFRCS) and the column for Reinforced Concrete Structure (RCS) could be the most common building structure. The increasing of the need for massive space hasaffected the size of building components for supporting the massive structure. However, the changing of components size makes inefficient space of building. Hence, to meet the need for acquiring efficient space comparing the budget and cost the new structure method, Concrete Filled Tube Steel (CFT), was developed. CFT is the structure for which steel tube instead of other materials such as wood for holding concrete is used. The most benefit of this one is to help in reducing the size of the building components and local buckling because of tube steel holding concrete. For this reason, this research will examine the probability of applying CFT on construction sites by using the concrete (800kgf/$\textrm{cm}^2$) especially for CFT through the data from the real size mock-up.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.458-461
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• 2004

The column for Steel Framed Reinforced Concrete Structure (SFRCS) and the column for Reinforced Concrete Structure (RCS) could be the most common building structure. The increasing of the need for massive space hasaffected the size of building components for supporting the massive structure. However, the changing of components size makes inefficient space of building. Hence. to meet the need for acquiring efficient space comparing the budget and cost the new structure method, Concrete Filled Tube Steel (CFT), was developed. CFT is the structure for which steel tube instead of other materials such as wood for holding concrete is used. The most benefit of this one is to help in reducing the size of the building components and local buckling because of tube steel holding concrete. For this reason, this research will examine the probability of applying CFT on construction sites by using the concrete $(800kg/cm^2)$ especially for CFT through the data from the real size mock-up.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.334-345
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• 2009

Pumped storage power plants are playing a significant role in the contribution to the stabilization of an electrical grid, above all by stable operation and fast reaction to sudden load respectively frequency changes. Optimized efficiency and smooth running characteristics both in pump and turbine operation, improved stability for synchronization in turbine mode, load control in pump mode operation and also short reaction times may be achieved using adjustable speed power units. Such variable speed power plants are applicable for high variations of head (e.g. important for low head pump-turbine projects). Due to the rapid development of power semiconductors and frequency converter technology, feasible solutions can be provided even for large hydro power units. Suitable control strategies as well as clear design criteria contribute significantly to the optimal usage of the pump turbine and motor-generators. The SIMSEN tool for dynamic simulations has been used for comparative investigations of different configurations regarding the power converter topology, types of semiconductors and types of motor-generators including the coupling to the hydraulic system. A brief overview of the advantages & disadvantages of the different solutions can also be found in this paper. Using this approach, a customized solution minimizing cost and exploiting the maximum usage of the pump-turbine unit can be developed in the planning stage of new and modernization pump storage projects.