• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.26-35
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• 2019

By operating servers, storage, and networking devices, Data centers consume a lot of power such as cooling facilities, air conditioning facilities, and emergency power facilities. In the United States, The power consumed by data centers accounted for 1.8% of total power consumption in 2004. The data center industry has evolved to a large scale, and the number of large hyper scale data centers is expected to grow in the future. However, as a result of examining the server share of the data center, There is a problem where the server is not used effectively such that the average occupancy rate is only about 15% to 20%. To solve this problem, we propose a Virtual Machine Reallocation research using virtual machine migration function. In this paper, we use meta-heuristic for effective virtual machine reallocation. The virtual machine reallocation problem with the goal of maximizing the idle server was designed and solved through experiments. This study aims to reducing the idle rate of data center servers and reducing power consumption simultaneously by solving problems.

• International Area Studies Review
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• v.21 no.1
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• pp.25-57
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• 2017

In this study, we analyzed the information asymmetry and the agency problem in major affiliated companies on the basis of the R&D investment. As a result of comparing how the R&D investment effects on major affiliated companies and the independent companies, even the achievement of R&D investment effects in a positive way to the firm value, the positive effect appears much lower on major affiliated companies comparing independent companies. In order to analyze the case, we investigated in a separate way according to the shareholding ratio and the affiliated market using the sample of the independent company and the group affiliated company. As a result of such analysis, the cause of this comes from the agency problem in major affiliated company, not the asymmetry information of affiliated company. After we analyzed the sample of the research depending on the affiliation market, we could observe there is a little impact of the asymmetry information in the outcome of the R&D investment of the major affiliated companies. In contrast, the companies which rated lower in the ratio of the shareholding appears much less in the positive effect of R&D investment compared to the companies which rated at a higher level. This phenomenon was also consistently observed when changing the research method or further subdividing the sample of companies belonging to the group based on the ownership share of major shareholders.

• Journal of Information Technology Applications and Management
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• v.13 no.3
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• pp.145-179
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• 2006

The measurement of informatization program effectiveness continues to be a central concern of both academics and practitioners. However, most studies of it have been inclined too heavily toward testing validity and reliability of evaluation measure to strengthen the theoretical rigor. Drawbacks of this approach have been pointed out as being unsuitable for evaluating the effectiveness of informatization program due to lack of practical relevance. The paper comprises four sections to solve the problem. 1) Through literature review of theoretical conceptual models in IS effectiveness and the domestic and foreign cases on informatization program, we establish the evaluation framework which consists of evaluation phases, 6 evaluation areas, and 22 evaluation items, and developed evaluation measures of each items. 2) Different researchers have addressed different aspects of attribute of measure. With comparing them to each other, 3 mutually exclusive criteria on coincidence analysis(usability of measurement. reliability of measurement. and validity of content) are identified. 3) Data are gathered from respondents in informatizaiton program-related organizations such as policy agency, management agency, support agency, and recipient agency. 4) The degree of coincidence of each evaluation measure are analyzed by course of an coincidence analysis procedure, which includes the reliability test, arithmetical test, and criteria validity test. The academic implication of this study is that researchers can gain an insight into the coincidence analysis to approach the problem of deciding on an indicator of performance for informatization program. There is also practical implication for applying the potential means of improving the practical relevance of conducting evaluating the informatization program.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.12 no.20
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• pp.123-138
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• 1989

The primary objective of the agency research in the game theory lives in the maintenance of Pareto is optimal condition for the optimal incentive contract. The basic concepts which are related to this objective are reviewed in connection with the general assumptions to model it, the moral hazard and adverse selection which arised from the information asymmetry, and finally the problem of risk distribution. The demand for auditing and the role of auditor have been addressed by ASOBAC. Issues which an auditor is explicitly introduced in a principal-agent framework have been addressed in this paper. These issues must be confronted to appropriately with the auditor, and to achieve an adequate understanding of optimal confronting arrangement with the auditor. The first step in introducing an auditor into this analysis is to examine the game-theoretic foundation of such a expended agency model. The Mathematical program formulated may not yield solution that are resonable. This arises because the program may call for the auditor and manager to play dominated Nash equilibra in some subgame. The nontrivial natures of the subgame implies that randomized strategies by the auditor and manager nay be of crucial importance. The possibilities for overcoming the randomized strategy problem were suggested; change the rule of the game and or impose covexity condition. The former seems unjustifiable in on auditing context, and the latter promising but difficult to achieve. The discussion ended with an extension of the revelation principle to the owner manager-auditor game, assuming strategies. An examination of the restriction and improvement direction of the basic concept of agency theory was addressed in the later part of this paper. Many important aspects of auditor incentives are inherently multiple-agent, multiple-period, multiple-objectine, phenomena and require further analyses and researches.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.128-141
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• 2015

Independent Component Analysis (ICA), one of the blind source separation methods, can be applied for extracting unknown source signals only from received signals. This is accomplished by finding statistical independence of signal mixtures and has been successfully applied to myriad fields such as medical science, image processing, and numerous others. Nevertheless, there are inherent problems that have been reported when using this technique: instability and invalid ordering of separated signals, particularly when using a conventional ICA technique in vibratory source signal identification of complex structures. In this study, a simple iterative algorithm of the conventional ICA has been proposed to mitigate these problems. The proposed method to extract more stable source signals having valid order includes an iterative and reordering process of extracted mixing matrix to reconstruct finally converged source signals, referring to the magnitudes of correlation coefficients between the intermediately separated signals and the signals measured on or nearby sources. In order to review the problems of the conventional ICA technique and to validate the proposed method, numerical analyses have been carried out for a virtual response model and a 30 m class submarine model. Moreover, in order to investigate applicability of the proposed method to real problem of complex structure, an experiment has been carried out for a scaled submarine mockup. The results show that the proposed method could resolve the inherent problems of a conventional ICA technique.

• IE interfaces
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• v.24 no.4
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• pp.341-350
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• 2011

This paper considers a problem of locating both distribution centers and retailers in a zone-dependent two-level distribution network where either a distribution center or a retailer should be located in each zone. Customer demands of each zone should be satisfied directly from either its own distribution center or its own retailer being supplied from a distribution center of another zone. The objective of the proposed problem is to minimize total cost being composed of distribution center/retailer setup costs and transportation costs. In the analysis, the problem is proved to be NP-hard, so that a branch-and-bound algorithm is derived for the problem. Numerical experiments show that the proposed branch-and-bound algorithm provides the optimal solution efficiently for some small problems.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.222-228
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• 2019

In recent years, in order to enhance the problem-solving skills required by the industrial field, universities have introduced the Problem-Based Learning(PBL) method to solve the problems caused by the lack of creativity, problem solving ability and self-directed learning. This study applied PBL class methods such as 'learning based on individual specific problems', 'self-directed learning', and 'small-group learning of small members' to practical design of fashion design. To do this, I conducted a questionnaire after conducting research based on the PBL module for one semester in a practical class of fashion design major at P University. As a result of the survey, the satisfaction and achievement of the class conducted by PBL learning method was improved than the existing teaching method. As such, if PBL class is used as a way of solving problems through close communication between professors and learners, it is expected to be established as a learner-centered education method that can improve creativity and professionalism.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.239-245
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• 2020

With the recent revised curriculum, the importance of exploring children's play through new teaching media is increasing in kindergarten. In this study, it is to use the robot 'Bee-bot' for early children to uncover the changes that children have through free exploration and play. As a result of comparing the change of scientific problem-solving ability of 3, 4, and 5-year-olds, there were significant changes in all three sub-elements. We propose to us scientific problem-solving ability test tools, propose and apply ideas for problem-solving, conclusion on problem-solving Building. Through this, it was found that unplugged play using 'Bee-bot' is meaningful as a play environment and as a teaching medium for children aged 3, 4 and 5 years old.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.629-638
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• 2016

In this paper, we investigate an energy-efficient resource allocation problem in a two-way relay (TWR) network consisting of multiple user pairs and an amplify-and-forward (AF) relay. As the users and relay have individual energy efficiencies (EE), we formulate a multi-objective optimization problem (MOOP). A single-objective optimization problem (SOOP) of the MOOP is introduced using a weighted-sum method, which achieves a single Pareto optimal point of the MOOP. To derive the algorithm for the SOOP, we propose a more tractable equivalent problem using the Karush-Kuhn-Tucker conditions of the SOOP, which guarantees convergence at the local optimal points. The proposed equivalent problem can be efficiently solved by the proposed iterative algorithm. Numerical results demonstrate the effectiveness of the proposed algorithm in achieving the optimal EE in multi-user AF TWR networks.

• International Journal of Advanced Culture Technology
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• v.7 no.3
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• pp.79-85
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• 2019

This study examined the effects of a robotics curriculum based on "Bee-Bot" on the scientific problem-solving ability on 5-year-old children. A robotics curriculum was also designed to enhance their scientific problem-solving ability. This study examined a 4-week robotics curriculum was conducted 12 times for 4 weeks. For this study, 14 children in kindergarten A in Korea were set up as a treatment group and 18 children in kindergarten B in Korea as a control group. It was found that children in the treatment group who engaged in the robotics curriculum using "Bee-Bot" performed better on scientific problem-solving tests. This finding indicates that an enhanced planning experience using "Bee-Bot" was beneficial for improving young children's scientific problem-solving ability. The implications for designing appropriate curricula using "Bee-Bot" robots for kindergarteners are addressed.