• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.499-508
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• 2008

Frequency regulation in off-normal conditions has been an important problem in electric power system design/operation and is becoming much more significant today due to the increasing size, changing structure and complexity of interconnected power systems. Increasing economic pressures for power system efficiency and reliability have led to a requirement for maintaining power system frequency closer to nominal value. This paper presents a decentralized frequency control framework using a modified low-order frequency response model containing a proportional-integral(PI) controller. The proposed framework is suitable for near-normal and emergency operating conditions. An $H_{\infty}$ control technique is applied to achieve optimal PI parameters, and an analytic approach is used to analyse the system frequency response for wide area operating conditions. Time-domain simulations with a multi-area power system example show that the simulated results agree with those predicted analytically.

• Journal of Families and Better Life
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• v.14 no.3
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• pp.121-136
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• 1996

The purpose of this study was to analyze a path model that investigated the relations among leisure expenditure leisure satisfaction and life satisfaction. For this purpose conceptual framework based on previous studies was suggested. The sample in this study consisted of 3,519 urban married couple living in Korea. Statistics employed for the analysis were frequencies means multiple regression and path annalysis. Empirical tests' results showed some evidence has been provided that supported the conceptual framework. In husband's model the household's leisure expenditure had vital direct effect on the husband's leisure satisfaction while it had not any effect on the husband's life satisfaction. Also in wife's model the household leisure expenditure had statistically significant direct effect on wife's life satisfaction however there was not any effect that mediated through wife's leisure satisfaction.

• ETRI Journal
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• v.18 no.3
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• pp.127-145
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• 1996

A new analytic framework based on a linear algebra approach is proposed for examining the performance of a direct sequence spread spectrum (DS/SS) slotted ALOHA wireless communication network systems with delay capture. The discrete-time Markov chain model has been introduced to account for the effect of randomized time of arrival (TOA) at the central receiver and determine the evolution of the finite population network performance in a single-hop environment. The proposed linear algebra approach applied to the given Markov problem requires only computing the eigenvector ${\prod}$ of the state transition matrix and then normalizing it to have the sum of its entries equal to 1. MATLAB computation results show that systems employing discrete TOA randomization and delay capture significantly improves throughput-delay performance and the employed analysis approach is quite easily and staightforwardly applicable to the current analysis problem.

• Nutrition Research and Practice
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• v.12 no.6
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• pp.459-468
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• 2018

BACKGROUND/OBJECTIVES: The Dietary Reference Intakes for Koreans (KDRIs), a set of reference intake values, have served as a basis for guiding a balanced diet that promotes health and prevents disease in the general Korean population. In the process of developing DRIs, a systematic review has played an important role in helping the DRI committees make evidence-based and transparent decisions for updating the next DRIs. Thus, the 2015 KDRI steering committee applied the systematic review framework to the revision process of the KDRIs. The purpose of this article is to summarize the revision process for the 2015 KDRIs by focusing on the systematic review framework. MATERIALS/METHODS: The methods used to develop the systematic review framework for 2015 KDRIs followed the Agency for Healthcare Research and Quality and the Tufts Evidence-based Practice Center. The framework for systematic review of the 2015 KDRIs comprised of the 3 following steps: (1) development of an analytic framework and refinement of key questions and search terms; (2) literature search and data extraction; and, (3) appraisal of the literature and summarizing the results. RESULTS: A total of 203,237 studies were retrieved through the above procedure, with 2,324 of these studies included in the analysis. General information, main results, comments of reviewers, and results of quality assessment were extracted and organized by study design. The average points of quality appraisals were 3.0 (range, 0-5) points for intervention, 6.1 (0-9) points for cohort, 6.0 (3-9) points for nested case-control, 5.4 (1-8) points for case-control, 14.6 (0-22) points for cross-sectional studies, and 7.0 (0-11) points for reviews. CONCLUSIONS: Systematic review helped to establish the 2015 KDRIs as a useful tool for evidence-based approach. Collaborative efforts to improve the framework for systematic review should be continued for future KDRIs.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1459-1460
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• 2004

An AHP-based framework for comprehensive comparison of several power technologies haas been developed. A questionnaire has been designed and is about to surveyed for extracting boty weight vectors and subjective evaluation values. The attitude of evaluator groups will be incorporated into these two types of quantification.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.233-236
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• 1997

This paper presents an improved IS(Information System) project selection methodology through the ANP(Analytic Network Process) method within a Goal Programming model framework. This new methodology helps us to overcome the weaknesses according to the dependence for each element and the feedback effects in hierarchy level of the AHP and the GP models. A simple numerical example and limits of this methodology reviewed.

• Journal of Korean Library and Information Science Society
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• v.21
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• pp.231-252
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• 1994

Library authorities are responsible for allocating its resources to best achieve library goals. This means the question of benefits and costs for library activities, as well as a n.0, pplication of economic theory to it. To consider these, this study dealt with theoretical analysis: 1) the nature of economic models, 2) economic theory to library activities, 3) and its a n.0, pplicability. However, economic model method allows us to use an analytic technique that is founded on library production and consumption. Thus, its major contribution is creation of a framework or system for maximizing the efficient library activities.

• Korean Management Science Review
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• v.12 no.2
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• pp.15-30
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• 1995

The objectives of this paper are to provide software developer selection criteria and to develop evaluation framework using AHP (Analytic Hierarchy Process). The selection criteria are extracted from Software Development Life Cycle, Quality Assurance, and Productivitiy of Organization. In this paper, the selection model is proposed and its examples are illustrated. Though some further research is required, the proposed model can be regarded as a basis of a DSS for the selection of the software developer.

• East Asian mathematical journal
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• v.31 no.5
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• pp.707-716
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• 2015

We consider a queueing system with N-limited nonstop forwarding. In this queueing system, when the server breaks down, up to N customers can be serviced during the repair time. It can be used to model an assembly line consisting of several automatic stations and a manual backup station. Within the framework of $Geo^X/D/1$ queue, the matrix analytic approach is used to obtain the performance of the system. Some numerical examples are provided.

• IE interfaces
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• v.15 no.4
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• pp.444-451
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• 2002

Recently, the interest in technology valuation is revived and increasing mainly due to the lack of suitability of the traditional valuation methods in explaining the market reaction to newly-emerging knowledge-oriented companies. Moreover, many firms are now gearing their efforts to the strategic use of technology asset such as technology licensing, transfer and commercialization. Firms are also trying to enhance their technological competitiveness by re-evaluating their technology level and thus identifying the strengths/weaknesses of their technology portfolio. To accomplish this objective, the development of an integrated evaluation system for technology assets is essential. This paper presents a technology valuation system developed for a steel manufacturing company in South Korea. The valuation framework is based on; (1) the multi-attribute evaluation of technological competitiveness using Analytic Hierarchical Process and; (2) the expected future benefit of the technology using four different methods of discounted cash flow estimation. The suggested framework will be easily applicable to various industries where technological competitiveness should be evaluated systematically.