• Journal of Information Processing Systems
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• v.16 no.2
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• pp.277-300
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• 2020

This paper presents a method for clustering short text documents, such as news headlines, social media statuses, or instant messages. Due to the characteristics of these documents, which are usually short and sparse, an appropriate technique is required to discover hidden knowledge. The objective of this paper is to identify the combination of document representation, document distance, and document clustering that yields the best clustering quality. Document representations are expanded by external knowledge sources represented by a Distributed Representation. To cluster documents, a K-means partitioning-based clustering technique is applied, where the similarities of documents are measured by word mover's distance. To validate the effectiveness of the proposed method, experiments were conducted to compare the clustering quality against several leading methods. The proposed method produced clusters of documents that resulted in higher precision, recall, F1-score, and adjusted Rand index for both real-world and standard data sets. Furthermore, manual inspection of the clustering results was conducted to observe the efficacy of the proposed method. The topics of each document cluster are undoubtedly reflected by members in the cluster.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.103-105
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• 2008

차세대 양방향데이터방송 (BIFS: BInary Format for Scenes) 서비스에서는 하향링크(downlink) 데이터 전송률에 상응하는 높은 상향링크(uplink) 데이터 전송률이 요구되고 있다. 이에 무선 전송 채널의 한정된 자원 환경 속에서 상향링크 전송용량 증대를 위한 주파수 효율성 제고 기술의 필요성이 대두되고 있다. 본 논문에서는 차세대 양방향데이터방송을 위한 다중 모바일(mobile) 사용자의 클러스터(cluster) 기반 상향링크 협동 다이버시티(cooperative diversity) 기법을 제안한다. 제안된 기법은 하나의 단일 안테나(single antenna) 방송 기지국과 다수의 단일 안테나 모바일 사용자가 있는 상향링크 시분할다중접속 (TDMA: Time Division Multiple Access) 시스템에서 데이터 지연허용(delay-tolerant)에 따라 클러스터를 구성하고 제곱 다이버시티 차수(square diversity order)의 협동 프로토콜(cooperative protocol)을 통해 높은 공간다이버시티 이득(spatial diversity gain)을 얻는다. 또한, 비대칭(asymmetric) 무선 채널 환경에서 공정성(fairness)을 보장한다.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.159-166
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• 2002

Today print media survives in tough struggle for existence and is deep to development of new technology as well as edit style and manufacture environment improvement that utilize actively a computer to establish new phase, and Desk Top Publishing or information industry department and link development are required. Propose analysis and solution way that this paper is examining concept of electronic publishing and manufacture progress, and analyze reciprocity degree of electronic publishing process through active and cluster analysis, and electronic publishing knows.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.183-187
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• 2020

The general Wi-Fi network connection structure is that a number of IoT (Internet of Things) sensor nodes are directly connected to one AP (Access Point) node. In this structure, the range of the network that can be established within the specified specifications such as the range of signal strength (RSSI) to which the AP node can connect and the maximum connection capacity is limited. To overcome these limitations, multiple middleware bridge technologies for dynamic scalability and load balancing were studied. However, these network expansion technologies have difficulties in terms of the rules and conditions of AP nodes installed during the initial network deployment phase In this paper, an intelligent edge computing IoT device is developed for constructing an intelligent autonomous cluster edge computing network and applying it to real-time road danger context aware and notification system through an intelligent risk situation recognition algorithm.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.55-58
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• 2011

This paper proposes a method of occluded number recognition by matching interest points. Interest points of input pattern are found via SURF features extracting and matched to interest points of clusters in database following three steps: SURF matching, coordinate matching and SURF matching on coordinate matched points. Then the satisfied interest points are counted to compute matching rate of each cluster. The input pattern will be assigned to cluster having highest matching rate. We have experimented our method to different numerical fonts and got encouraging results.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1995.06a
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• pp.83-86
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• 1995

Many image display devices allow only a limited number of colors to be simultaneously displayed. In displaying of natural color image using color palette, it is necessary to construct an optimal color palette and map each pixel of the original image to a color palette with fast. In this paper, we proposed the clustering algorithm using local region block centered one color cluster in the prequantized 3-D histogram. Cluster pairs which have the least distortion error are merged by considering distortion measure. The clustering process is continued until to obtain the desired number of colors. Same as the clustering process, original color image is mapped to palette color via a local region block centering around prequantized original color value. The proposed algorithm incorporated with a spatial activity weighting value which is smoothing region. The method produces high quality display images and considerably reduces computation time.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.109.1-109.1
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• 2011

Shock waves are ubiquitous in astrophysical environments. In particular, shocks formed by merger of subclumps, infall of matter and internal flow motion in intracluster media (ICMs) and cluster outskirts are relatively weak with Mach number M ${\lesssim}$ a few. At such weak shocks, it has been believed that the diffusive shock acceleration (DSA) of cosmic rays is rather inefficient. Yet, the presence of nonthermal phenomena, such as radio halos and relics, suggests that contrary to the expectation, DSA as well as magnetic field amplification should operate at weak shocks in cluster environments. We recently initiated a study of weak, collisionless, astrophysical shocks using a PIC(Particle-in-Cell) code. The PIC code describes the motion of electron and ion particles under the electromagnetic field which is represented in grid zones. Here, we present a preliminary work of one-dimensional simulations. We show how shocks are set up as the turbulent electromagnetic field is developed in the shock transition layer, and discuss the implication on DSA and magnetic field amplification.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1336-1342
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• 2012

In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.49.2-49.2
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• 2019

Clusters of galaxies shape up through a series of hierarchical mergers. It is believed that major mergers lead to cluster-wide shock waves, which are manifested as radio relics. The 1RXS J0603.0+4213 and CIZA J2242.8+5301 clusters, for instance, contain Mpc-size giant radio relics in the outskirts. Synchrotron emission from these radio relics reveals the presence of relativistic electrons and the magnetic fields of a few ${\mu}G$ strength. The presence of such magnetic fields in the ICM has been explained by the so-called small-scale turbulent dynamo. To get quantitative measures for magnetic fields in clusters of galaxies, we investigate the development of turbulence and the follow-up amplification of magnetic fields through three-dimensional numerical magnetohydrodynamical (MHD) simulations. The turbulence is induced in highly stratified cluster media, and driven sporadically by major mergers. We here present the results, aiming to answer whether the turbulence dynamo scenario can explain the observed strength and scale of magnetic fields in clusters. Also, we discuss whether the observed properties of giant radio relics can be reproduced in our simulations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.109-112
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• 2020

사람 재인식을 수행하기 위해서 많은 연구들이 진행되어 좋은 결과들을 보였다 그러나 이 결과들은 라벨이 있는 도메인에서의 지도 학습으로 얻은 결과들이었다. 라벨이 없는 도메인에서의 사람 재인식의 성능은 아직 많이 부족한 상태이다. 사람 재인식을 수행하고자 하는 목표 도메인에 반해 주어진 소스 도메인에서는 라벨이 풍부하다. 지금까지의 논문에서는 소스 도메인에서의 사람 이미지를 목표 도메인의 이미지처럼 만들어서 소스 도메인에서 높은 성능을 보이는 사람 재인식기를 목표 도메인에서도 잘 동작하도록 학습하는 방법들이 주를 이루었다. 하지만 이 방법에서는 소스 도메인의 사람 이미지를 목표 도메인의 이미지와 비슷하게 만들기만하고 사람의 신원에 대한 일관성을 유지시키지는 못하였다. 본 논문에서는 비지도 도메인 적응 사람 재인식을 수행하기 위해 클러스터 일관성(cluster consistency)을 유지하는 기법을 제안한다. 제안한 방법은 사람의 신원에 대한 일관성을 유지시켜서 사람 재인식의 성능을 높인다.