• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.107-110
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• 2015

In this paper, we propose a coalitonal game theoritic approach to the power control problem in resource-constrained wireless sensor networks, where the objective is to enhance power efficiency of individual sensors while providing the QoS requirements. We model this problem as two-sided one-to-one matching game and deploly deferred acceptance procedure that produces a single matching in the core. Furthermore, we show that, by applying the procedure repeatedly, a certain stable state is achieved where no sensor can anticipate improvements in their power efficiency as far as all of them are subject to their own QoS constraints. We evaluate our proposal by comparing them with cluster-based and the local optimal solution obtained by maximizing the total system energy efficiency, where the objective function is non-convex.

• Journal of Korea Game Society
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• v.15 no.3
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• pp.107-122
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• 2015

The aim of this study is to suggest the strategy and policy to promote world class game industrial complex through the analysis of game contents business ecosystem in Seongnam. As a result of analysis, At present of the game contents industry in Seongnam as ecosystem is challenged in many-side as followings. 1)Lack of interaction between core game contents businesses and extended network businesses in same area. 2)Imbalanced relationships between game contents conglomerate and small and medium sized businesses. 3)Insufficient game contents optimized human resource and development program. This study provides a stepping stone for regional industrial ecosystem of game industry and new possibilities of application about regional industry analysis.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.350-353
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• 2020

The validity of the calculation method based on the local mode in hydrogen-bonded water molecules was investigated by comparing the frequencies of the local and normal modes of OH stretching vibration in water molecules. By calculating a monomer, dimer, and trimer of water molecules using a quantum chemical ab initio theory, we examined how the frequencies of the local and normal modes and the anharmonicity of local modes vary with molecular cluster size. It was shown that, as the number of molecules increases from monomer to trimer, the anharmonicity of OH bonds increases and the difference between local and normal mode frequencies decreases. This confirms that local-mode-based calculations that can easily handle the anharmonicity can be appropriate for the calculation of the OH stretching frequency of water molecules in the condensed phase.

• Journal of the Korean housing association
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• v.16 no.6
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• pp.1-7
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• 2005

도시화는 현대사회의 가장 큰 특징이며 도시가 성장하면서 과거의 기능이 변화하고 도시내부의 공간구조가 점차 기능적으로 분화하는 경향이 있다. 그 중 가장 주목할 만한 것 중의 하나는 주거지역의 입지변화와 공간적 확산과정에서 나타나는 주거지 분화현상이다. 도시생태학자 Hoyt은 주거지 이동패턴에 대하여 도시 내의 주거지분포 패턴을 결정짓는 핵심적인 요인으로 최고지대를 지불할 수 있는 부유층의 주거입지 선택에 따라 전체 도시의 계층별 주거분포가 영향을 받게 된다고 주장하였다. 서울은 소규모로 계획된 역사도시에서 인구 1000만의 대도시로 성장하여 오면서 많은 구조적 변화를 경험하여 현재의 공간구조를 이루게 되었다. 현재 전체 서울의 주택지는 동일한 것이 아니고 각종 주위환경에 따른 성격과 특성을 달리하는 요소로 구성되어 있다. 이 특성을 달리하는 주택지들이 모여서 각기 상이한 역할을 수행하고 서로 기능적 관계를 맺으면서 주택지를 형성하고 있다. 선형이론(Hoyt's Sector theory)에 따르면 고급주택지역의 도시 공간구조에 많은 영향을 미치고 있다고 주장하였다. 그럼에도 불구하고 서울의 고급주택지역의 분포와 그 입지 특성에 관한 연구는 미비한 실정이다. 본 연구의 목적은 서울시 고급주택지역의 분포를 형성하는 원인을 규명하는데 있다. 고급주택지의 지역적 분포를 파악하여 그 입지 성향과 특성을 알게 되면 도시의 토지이용계획, 특히 주거지계획에 도움이 될 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.35-40
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• 2009

FCM 알고리즘은 입력 벡터와 각 클러스터의 유클리드 거리를 이용하여 구해진 소속도만를 비교하여 데이터를 분류하기 때문에 클러스터링 된 공간에서의 데이터들의 분포에 따라 바람직하지 못한 클러스터링 결과를 보일 수 있다. 이러한 문제점을 개선하기 위해 대칭적 성질을 이용하는 대칭성 측도에 퍼지 이론을 적용하여 군집간의 거리에 따른 변화와 군집 중심의 위치, 그리고 군집 형태에 따라 영향을 덜 받는 개선된 FCM이 제안되었다. 본 논문에서는 효과적으로 패턴을 분류하기 위해 개선된 FCM 알고리즘을 적용한 개선된 하이브리드 네트워크를 제안한다. 제안된 하이브리드 네트워크는 개선된 FCM 알고리즘을 입력층과 중간층의 학습구조 적용하고 중간층과 출력층의 학습구조는 일반화된 델타학습법을 적용한다. 제안된 방법의 인식성능을 평가하기 위해 2차원 좌표평면 상의 데이터를 기존의 Max_Min 신경망을 이용한 FCM 기반 RBF 네트워크와 FCM 기반 RBF 네트워크, HCM 기반 네트워크와 제안된 방법 간의 학습 및 인식 성능을 비교 및 분석하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.3
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• pp.111-119
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• 2008

This paper combines fuzzy concepts with an existing dynamic performance isolation technique in order to improve the response time performance of a Web server supporting differentiated services. A load balancing mechanism based on the fuzzy control technique is developed in such a way that ambiguous situations caused by workload estimation of cluster-based Web servers, client request rates, and dynamic request rates can be represented in an effective way. In addition, we verify that the fuzzy-based performance isolation technique improves the performance and robustness of differentiated service systems efficiently through comparing 95-percentile of response time between the fuzzy-based Performance isolation technique and the existing one, which do not use the fuzzy concept.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.160-168
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• 2008

We completed a new cluster system based on WDM by proposing virtual topology reconfiguration schemes. The key idea of the proposed scheme Is to construct a set with the longest chains of requests of connecting nodes which need to be assigned a wavelength. All the sets have no common factor, that is, there is no duplicated link among the requests of connecting. After making the set satisfying this condition, we could assign a wavelength to per corresponding set. We could reconfigure a virtual topology with this scheme collectively. we compared our scheme to existing approaches by the OWns simulation tool. As the results, we gained improved performances, reducing 10% of blocking rate and improving 30% of ADM utilization in terms of the blocking probability and the ADM utilization.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1806-1813
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• 2002

It is well known that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure, a classical optimization technique was adopted by previous researchers. That technique overcame the difficulty of finding the intersection point of the superposed contours that correspond to the eigenfrequency caused by the crack presence. However, it is hard to select a trial solution initially for optimization because the defined objective function is heavily multimodal. A method is presented in this paper, which uses continuous evolutionary algorithms(CEAs). CEAs are effective for solving inverse problems and implemented on PC clusters to shorten calculation time. With finite element model of the structure to calculate eigenfrequencies, it is possible to formulate the inverse problem in optimization format. CEAs are used to identify the crack location and depth minimizing the difference from the measured frequencies. We have tried this new idea on a simple beam structure and the results are promising with high parallel efficiency over about 94%.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.461-468
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• 2001

Though shared virtual memory (SVM) system promise low cost solutions for high performance computing they suffer from long memory latencies. These latencies are usually caused by repetitive invalidations on shared data. Since shared data are accessed through synchronization and the patterns by which threads synchronizes are repetitive, a prefetching scheme bases on such repetitiveness would reduce memory latencies. Based on this observation, we propose a prefetching technique which predicts future access behavior by analyzing access history per synchronization variable. Our technique was evaluated on an 8-node SVM system using the SPLASH-2 benchmark. The results show the our technique could achieve 34%~45% reduction in memory access latencies.

• Journal of the Korean Geographical Society
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• v.47 no.4
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• pp.522-540
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• 2012

The main aim of the paper is to identify the position or status of Korean economic geography in changing global economic geography by reviewing papers published in Korean geographical journals since the mid-1950s. Since the late 20th century as economic geography has developed significantly with the introduction of new research issues, methodologies, and theory and concepts, economic geography in Korea also has gone through rapid development in terms of both quantitative and qualitative perspectives. The paper attempts to analyze trends in Korean economic geography by reviewing agricultural, industrial, commercial geographies, and others since the mid-1950s. The review of economic geography in Korea would be based on four periods classified by research issues and approaches; foundation (~1950s), positioning (1960s and 1970s), jump and rush (1980s and mid-1990s), and transitional period (late 1990s~). Agricultural geography in Korea has decreased due to increases of the interests in industrial geography since the 1980s. In particular, since the late 1990s industrial geography has undergone a significant transition in accordance with the emergence of new theories of institutional perspectives, centering around issues on value chains, innovative cluster, cooperative and competitive networks, foreign direct investment, flexible specialization and venture ecology. Along with this, there has been changes in the interest of commercial geography in Korea from researches on periodical markets, the structure of store formats, and distributions by commodity, to researches on producer services and retailer's locational behaviors and commercial supremacy according to the emergence of new store formats. Since the late 1990s, many researches and discussions associated with the new economic geography began to emerge in Korea. Various research issues are focused on analyzing changes of local, regional and global economic spaces and their processes in relation to institutional perspectives, knowledge and innovation, production chain and innovative networks, industrial clusters and RIS, and geographies of service. Although economic geography in Korea has developed significantly both in quantitative and qualitative perspectives, we pointed out that it has still limited in some specific scope and issues. Therefore, it is likely to imply that its scope and issues should be diversified with new perspectives and approaches.