• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.117-128
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• 2020

The aim of this study was to examine price sensitivity of industrial products purchased via a group buying system and how industrial products for a group buying system differ from general industrial products, and then identify the major factors in selecting products and the important determinants in purchasing industrial products for school foodservices. The survey was conducted with 250 dietitians (teachers) in Gyeonggi-do Province, who were using industrial products for a group buying system and general industrial products. A paired t-test showed a difference in satisfaction between industrial products for a group buying system and general industrial products by factors, while statistically significant differences were found for red pepper paste, fermented soybean paste and soy sauce in all nine satisfaction factors, including product quality, packaging state, labeling, hygiene, item diversity, specification diversity, price appropriateness and supply. Moreover, analyzing price sensitivity for industrial products for a group buying system, using the PSM method with respect to the issue of high price, showed that the respondents considered that the current unit purchase prices were high for all items investigated. This study suggests that schools would purchase more industrial products for a group buying system, when the pricing of the products are considered with the purchase intention of dietitians (teachers).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1579-1602
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• 2020

In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system's multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1687-1692
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• 2002

The problem analyzed here is a sheet metal forming process which requires a drawbead. The drawbead provides the sheet metal enough tension to be deformed plastically along the punch face and consequently, ensures a proper shape of final products by fixing the sheet to the die. Therefore, the optimum design of drawbead is indispensable in obtaining the desired formability. A static-explicit finite element analysis is carried out to provide a perspective tool for designing the drawbead. The finite element formulation is constructed from static equilibrium equation and takes into account the boundary condition that involves a proper contact condition. The deformation behavior of sheet material is formulated by the elastic-plastic constitutive equation. The finite element formulation has been solved based on an existing method that is called the static-explicit method. The main features of the static-explicit method are first that there is no convergence problem. Second, the problem of contact and friction is easily solved by application of very small time interval. During the analysis of drawbead processes, the strain distribution and the drawing force on drawbead can be analyzed. And the effects of bead shape and number of beads on sheet forming processes were investigated. The results of the static explicit analysis of drawbead processes show no convergence problem and comparatively accurate results even though severe high geometric and contact-friction nonlinearity. Moreover, the computational results of a static-explicit finite element analysis can supply very valuable information for designing the drawbead process in which the defects of final sheet product can be removed.

• Journal of Technology Innovation
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• v.12 no.2
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• pp.209-225
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• 2004

This study aims to explore and understand the role of knowledge intensive service activities in the industrial innovation of Korea. It analyzes public and private service inputs to the innovation of manufacturers. The contribution of KISs to the innovation of both service suppliers and manufacturers was analyzed by using survey questionnaire. The results of the analysis revealed that the contribution of KISs to the innovation capability of manufacturers is significant. Large manufacturers that hold internal capability to supply KISs are also active in using external KISs. The manufacturing firms that utilized KISs intensively proved to be more innovative than those did not. Heavy KISs users also entertained benefits of capability enhancement as they improved monitoring and achieved efficient application of knowledge asset into product and process innovation. The role of public KISs in the innovation of manufacturers appeared to be indirect and done mainly through education and public R&D activities. Direct input, such as public software service, was not utilized as much in service suppliers themselves. The major reason is that public KISs may not be relevant to their actual needs. Manufacturers have implemented both tighter integration of familiar KISs and loosely coupled unfamiliar KISs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1341-1350
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• 2017

In this paper, a high reliability 30W DC-DC converter is designed considering military standard (MIL-STD) for military applications such as guided weapon and aircraft. The performances and specifications of conventional military grade DC-DC converter are practically analyzed. The requirements for military grade DC-DC converter are established in consideration of MIL-STD and analysis results of conventional product. Two isolated DC-DC converter, forward and fly-back converter, are designed and compared to determine topology. From experimental results under various operating conditions, the forward topology satisfied performances and specifications of MIL-STD for military DC-DC converter.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.16-21
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• 2017

Fire or electrical problem while DC electric traction vehicle operation caused by various reasons can lead to not only suspension of the operation, but also severe aftermath such as massive casualty. In this paper, fire analysis on DC electric traction vehicle caused by electrical breakdown on line breaker, which is in connection with the power supply, is presented. When the electric arc, the by-product of frequent line breaker operation, is not fully diminished, it leads to electrical breakdown and fire. Especially, electrical breakdown can be easily induced by the open-and-close operation of inner contractor inside line breaker, eventually followed by ground fault and generation of transient current. Electric arc is consequent on the ground fault and acts as possible ignition source, leading to fire. Also, during the repetitive operation of the line breaker, the contactor is separated each other and some copper powder is generated, and the copper powder provided breakdown path, resulting in fire.

• Journal of the Korean housing association
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• v.14 no.3
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• pp.147-156
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• 2003

A small apartment housings in Korea, which is built mass-product from 1980s, are dissatisfied, in spite of good condition, due to the growing living areas and changing lifestyle of the residents. Many of them confronted with slum areas and the kinds of housing stock accumulated much more in Korean contexts. For the existing small houses, it could be discuss an adaptation model to the increasing requirement standards of the house residents; wider living area, new facilities and a style of new residence. A social policy for elderly people who are handicap in physical and economical aspects, is home stay system rather than national support. But it is not easy to find the three generation family house in Korea context, specially apartment house. This paper deals with the vertical unification typology of two dwelling units to one, in order to supply three generation houses by remodel existing small apartment houses constructed by Korea National Housing Corporation. The use of convert houses into vertical expansion are expected to be a house of three generation family, it can also enhance privacy against conflictive activities in a house. And also the merging types of two dwelling units into one can be used as a device to get rid of the monotonous characteristics and gain diversity in the declining stock housing.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.43-50
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• 2020

Many companies around the world are applying CMMI to improve the organization's ability to perform projects, and many others are pushing to obtain CMMI certification as more and more of them are offered as preconditions for participation in projects or supply product. Organizations with high maturity such as CMMI Level 4~5, analyze the accumulated R&D data of the organization and establish the performance management model so that R&D performance is continuously managed. So this paper shows the R&D performance management model made by LIGNex1 which is certificated with CMMI Level 5 organization and the case applied to the project, including its effectiveness.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.2
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• pp.125-137
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• 2010

This study focuses on the problem of scheduling wafer lots of several product families in the deposition workstation in a semiconductor wafer fabrication facility. There are multiple identical parallel machines in the deposition workstation, and two types of setups, record-dependent setup and family setup, may be required at the deposition machines. A record-dependent setup is needed to find optimal operational conditions for a wafer lot on a machine, and a family setup is needed between processings of different families. We suggest two-phase heuristic algorithms in which a priority-rule-based scheduling algorithm is used to generate an initial schedule in the first phase and the schedule is improved in the second phase. Results of computational tests on randomly generated test problems show that the suggested algorithms outperform a scheduling method used in a real manufacturing system in terms of the sum of weighted flowtimes of the wafer lots.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.390-400
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• 2013

The purpose of this study is to investigate the effect of RTE characteristics on SCM performance. Extant approaches for evaluating the SCM performance adopt financial measures, non-financial measures, Balanced Score Card (BSC) methodology and Supply Chain Operations Reference (SCOR) methodology etc., but researches on SCM performance measurement are not sufficiently reviewed. In this study, SCM performance is measured with the Combinative Capabilities which are divided into four categories of product quality, delivery speed, process flexibility, price leadership. The experimental results with the three factors of visibility, agility and combinative capabilities variables show the followings: (i) Visibility had a significant impact on agility. (ii) Visibility had a significant impact on combinative capabilities. (iii) Agility also had a significant impact on combinative capabilities.