• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.67-75
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• 2009

IEEE 802.11 WLAN(Wireless Local Area Network) standard is currently developing with increased wireless internet demand. Study trends of IEEE 802.11n for high throughput show two aspects, enhanced system throughput using aggregation among packets in MAC(Medium Access Control) layer, and better data rates adapting MIMO(Multiple-Input Multiple-Output) in PRY(Physical) layer. But, no one demonstrates IEEE 802.11n system performance results considering MAC and PRY connection. This paper adapts A-MPDU(Aggregation-MAC Protocol Data Unit) method in MAC layer and MIMO in PRY layer for IEEE 802.11n system. Consequently, Simulation results show enhanced throughput and data rates compared to existing system. Also, We use NS-2(Network Simulator-2) considering MAC and PRY connection for reality.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.04a
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• pp.78-83
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• 2000

MPLS는 현재 인터넷에서 전송지연, QoS, CoS와 같은 문제점을 2계층 스위칭 기법을 통하여 해결하기 위한 차세대 인터넷 프로토콜이다. 한편, 2계층과 3계층의 특성을 동시에 수용하는 MPLS는 CBT 멀티캐스트 프로토콜을 적용할 때 트래픽이 집중하게 된다. 이는 MPLS가 갖는 트래픽 엔지니어링의 장점을 제공하지 못한다. 따라서 본 논문에서는 트래픽의 집중을 분산시키는 알고리즘을 제안하고 시뮬레이션을 통하여 분석한다.

• KIISE Transactions on Computing Practices
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• v.21 no.6
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• pp.436-441
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• 2015

There are many types of clustering algorithms such as centroid, hierarchical, or density-based methods. Each algorithm has unique data grouping principles, which creates different varieties of clusters. Ordering Points To Identify the Clustering Structure (OPTICS) is a well-known density-based algorithm to analyze arbitrary shaped and varying density clusters, but the obtained clusters only correlate loosely. Hierarchical agglomerative clustering (HAC) reveals a hierarchical structure of clusters, but is unable to clearly find non-convex shaped clusters. In this paper, we provide a novel hierarchy generation framework and application which can aid users by combining the advantages of the two clustering methods.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.259-260
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• 2013

고장과 복구를 함께 고려한 성능분석 SRN 모델을 계층모델링 기법을 이용하여 개발한다. 상위 계층모델은 고장과 복구에 관련된 시스템 상태를 나타내는 구조상태(structure state) 모델이고, 하위 계층모델은 주어진 구조상태에서 시스템의 상태를 표시할 수 있는 SRN 모델을 사용한다. 성능지표로 블러킹확률을 구한다.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.440-447
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• 2011

Selecting a suitable place is to determine the attributive conditions and qualified areas for the aim as factors and is to be fulfilled systematically for selecting the area which satisfies all these. This research tries to achieve a rational suitability analysis of residential development using the GIS modeling method and the hierarchical analysis process. A spatial and attributive analysis has been systematized for selecting a suitable place for the study and GIS analysis model has been used for the effective conclusion drawing for different levels. As a next step, a quantitative and qualitative evaluation index was created through complex consideration of the criteria and decision factors of the location selection, and weights were added depending on the relative importance of these factors. In particular, 3D terrain model simulation method has been used in order to reflect the aesthetic factors of the scenery which is an element of the subjective evaluation factors and considered qualitative and subjective evaluation factors which were not considered for the existing AHP technique. After the research, a location that satisfies complex requirements was found rapidly and accurately through the GIS model and hierarchical analysis.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.217-222
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• 2015

Clustering is one of important data mining techniques known as exploratory data analysis and is being applied in various engineering and scientific fields such as pattern recognition, remote sensing, and so on. The method organizes data by abstracting underlying structure either as a grouping of individuals or as a hierarchy of groups. Weather radar observes atmospheric objects by utilizing reflected signals and stores observed data in corresponding coordinate. To analyze the radar data, it is needed to be separately organized precipitation and non-precipitation echo based on similarities. Thus, this paper studies to apply clustering method to radar data. In addition, in order to solve the problem when precipitation echo locates close to non-precipitation echo, fuzzy logic based clustering method which can consider both distance and other properties such as reflectivity and Doppler velocity is suggested in this paper. By using actual cases, the suggested clustering method derives better results than previous method in near-located precipitation and non-precipitation echo case.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.466-466
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• 2015

지역빈도해석은 수문학에서 오랜 역사를 갖고 있으며, 수년에 걸쳐 수문학적 변량의 정량적 추정을 위해 다양한 접근방법들이 제안되어 왔다. 그러나 제안된 방법들의 가설설정 수준이 높기 때문에 실제 적용에 제약이 많고, 적용 시에도 예측에 대한 불확실성이 높은 문제점이 있다. 본 연구에서는 이러한 문제점을 개선하기 위한 방법으로 계층적 베이지안 모델을 이용한 지역빈도해석 모형을 제안하고자 한다. 본 모형은 2개의 계층적 구조로 구성된다. 첫번째 계층은 재현기간별 GEV 분포의 매개변수를 정규화하여 주변분포로 설정하고, Kriging 기법을 이용하여 지형학적, 기상학적 정보들과 극치강수량 효과를 적합시켜 공간적 이질성과 미계측 유역에 대한 효과적인 보간을 가능하게 한다. 두번째 계층은 지점의 특성을 나타내는 매개변수들간의 공분산을 Bayesian 모델에 연계하여 매개변수들의 공간적 변동성을 나타낸다. 2개 계층의 결합확률분포는 MCMC 기법을 이용하여 예측값에 대한 불확실성을 정량적으로 분석하게 된다. 본 모형을 통해 홍수량 추정 시 필요한 시간 단위 극치강수량의 공간적 분포를 효과적으로 추정할 수 있을 것으로 판단된다.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.1-9
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• 2019

The purpose of this study is to examine the system of the Jeokbyeok-ga's version using the Computer analysis technique of bibliographies and to examine the achievements of the Jeokbyeok-ga's version studies. First, in order to provide basic data for analysis, a raw corpus was constructed for 46 species of Jeokbyeok-ga. Through this, the common narrative units of the Jeokbyeok-ga were identified as 5 layers, and thus 146 individual paragraphs could be extracted. Based on the encoded corpus, we tried to measure the similarity and the distance between the two. Next, we applied the Multidimensional scaling method, Hierarchical cluster analysis and Cladistic analysis method of the system to confirm the distribution of versions group and it was possible to visually grasp the distance between versions and the system of the work. As a result of analyzing Computer analysis technique of bibliographies, it was found that version's group of the Jeokbyeok-ga was divided into a Wanpan(完板) series and Changbon(唱本) series. Also, it was possible to examine the influence relationship between the Pansori's traditions and transmission.

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.61-76
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• 2015

In general, we have utilized the hierarchical concept tree as a crucial data structure for indexing huge amount of textual data. This paper proposes a generality rank-based method that can automatically develop hierarchical concept structures with the Wikipedia data. The goal of the method is to regard each of Wikipedia articles as a concept and to generate hierarchical relationships among concepts. In order to estimate the generality of concepts, we have devised a special ranking function that mainly uses the number of hyperlinks among Wikipedia articles. The ranking function is effectively used for computing the probabilistic subsumption among concepts, which allows to generate relatively more stable hierarchical structures. Eventually, a set of concept pairs with hierarchical relationship is visualized as a DAG (directed acyclic graph). Through the empirical analysis using the concept hierarchy of Open Directory Project, we proved that the proposed method outperforms a representative baseline method and it can automatically extract concept hierarchies with high accuracy.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.793-797
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• 2008

To achieve flexible visual contents adaptation for multimedia communications, the ISO/IEC MPEG & ITU-T VCEG form the JVT to develop an SVC amendment for the H.264/AVC standard. JVT uses inter-layer prediction that can improve the rate-distortion efficiency of the enhancement layer. But inter-layer prediction causes computational complexity to be increased. In this paper, we propose a fast mode decision for inter frame coding. It makes use of the correlation between optimized prediction mode and its RD cost. Experimental results show that the proposed schemes save up to 38% of encoding time with a negligible coding loss and bit-rate increase.