• The Journal of the Korea Contents Association
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• v.5 no.2
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• pp.79-85
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• 2005

In order to handle client's requests while multiple servers seamlessly work in the web server cluster environment, it is vital to implement a router that execute a routing using TCP information and requested target content. The implemented package software measured packet volume that was generated from data generator, virtual server, and server 1, 2, 3, and could find out traffic distribution toward Server 1, 2, 3. As the result of the study shows, Round Robin Algorithm ensured definite traffic distribution, unless incoming data loads differ much. Although error levels were high in some partial cases, they were eventually alleviated by repeated tests for a longer time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3769-3789
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• 2018

Social pedestrian groups are the basic elements that constitute a crowd; therefore, detection of such groups is scientifically important for modeling social behavior, as well as practically useful for crowd video understanding. A social group refers to a cluster of members who tend to keep similar motion state for a sustained period of time. One of the main challenges of social group detection arises from the complex dynamic variations of crowd patterns. Therefore, most works model dynamic groups to analysis the crowd behavior, ignoring the existence of stationary groups in crowd scene. However, in this paper, we propose a novel unified framework for detecting social pedestrian groups in crowd videos, including dynamic and stationary pedestrian groups, based on spatiotemporal-oriented energy measurements. Dynamic pedestrian groups are hierarchically clustered based on energy flow similarities and trajectory motion correlations between the atomic groups extracted from principal spatiotemporal-oriented energies. Furthermore, the probability distribution of static spatiotemporal-oriented energies is modeled to detect stationary pedestrian groups. Extensive experiments on challenging datasets demonstrate that our method can achieve superior results for social pedestrian group detection and crowd video classification.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.26.2-26.2
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• 2009

The Solar and Space Weather Research Group (SOS) in Korea Astronomy and Space Science Institute (KASI) is constructing the Space Weather Prediction Center since 2007. As a part of the project, we are developing automatic real-time system of the global 3-D magnetohydrodynamics (MHD) simulation. The MHD simulation model of earth's magnetosphere is designed as modified leap-frog scheme by T. Ogino, and it was parallelized by using message passing interface (MPI). Our work focuses on the automatic processing about simulation of 3-D MHD model and visualization of the simulation results. We used PC cluster to compute, and virtual reality modeling language (VRML) file format to visualize the MHD simulation. The system can show the variation of earth's magnetosphere by the solar wind in quasi real time. For data assimilation we used four parameters from ACE data; density, pressure, velocity of solar wind, and z component of interplanetary magnetic field (IMF). In this paper, we performed some initial tests and made a animation. The automatic real-time system will be valuable tool to understand the configuration of the solar-terrestrial environment for space weather research.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.927-934
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• 2002

In order to provide various multimedia services in a wireless network, the call admission control for wireless channels should be resolved at the time of call setup and handoff by moving mobile terminal. In this paper. we propose a reliable DCAC( Distributed Call Admission Control)scheme using virtual cluster concept. The proposed DCAC scheme considers the state of $1^{st}$ and $2^{nd}$ adjacent cells to provide a reliable call handling. The proposed scheme is analyzed by simulations and mathematical methods.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.151-154
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• 2002

갈수록 증가하는 인터넷 사용자의 서비스 요구량에 대처하기 위해, 부하 분산 기능을 갖는 클러스터 시스템의 이용이 늘어가고 있다. 본 연구에서는 클라이언트에게 보다 향상된 응답 성능을 제공하기 위해 사용되는 RR(Round Robin), WRR(Weighted Round Robin), LC(Least Connection), WLC(Weighted Least Connection) 부하 분산 알고리즘에 대해서, 클라이언트로부터 인입되는 7 가지 요구 수신 패턴에 따른 부하 분산 응답 특성을 분석하고 그 결과를 논한다. 이를 위해, 실제 시스템의 측정 결과를 토대로 단위 시간 당 인입되는 클라이언트의 요구량 변화를 7 가지 패턴으로 분류하였고, 리눅스 가상 서버(LVS: Linux Virtual Server) 클러스터 시스템을 대상으로 7 가지 요구 패턴에 대한 부하 분산 응답 특성을 얻었다. 본 연구를 통해서 클라이언트 요구랑 변화 패턴에 따른 최적의 부하 분산 알고리즘을 제시할 수 있었다. 본 연구 결과는 향후 효율적인 동적 부하 분산 연구에 좋은 참고가 될 것이다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.310-312
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• 2005

무선 인터넷 프록시 서버 클러스터에서 부하 분산기는 사용자의 요청을 각 서버(호스트)로 분산시키는 역할을 한다. 리눅스 가상 서버(LVS: Linux Virtual Server)는 소프트웨어적으로 사용되는 부하 분산기로서 여러 가지 스케줄링 방식들을 가지고 있다. 그러나 부하 분산시에 서버(호스트)의 유동적인 부하 정보를 반영하지 못하는 단점이 있다. 이에 개선된 방식으로 서버의 동시 연결 개수에 따라 상한계(Upper Bound)와 하한계(Lower Bound)를 설정하고, 요청을 분산하는 동적 스케줄링(Dynamic Scheduling)이 존재한다. 그러나 사용자의 요청 컨텐츠에 따라 상한계와 하한계가 바뀔 수 있음에도 불구하고 이 값들이 고정되어 있다는 단점을 가진다. 본 논문에서는 호스트 부하 정보에 기반한 스케줄링 방식을 제안한다. 제안된 방식은 호스트의 부하 정보를 바탕으로 사용자의 요청을 분산하였으며, 사용자의 요청에 따라 상한계와 하한계가 바뀔 수 있음을 고려하여 상한계와 하한계를 설정하지 않고 사용자 요청 컨텐츠에 따라 적절하게 요청이 분배되도록 하였다. 16대의 컴퓨터를 사용하여 실험을 수행하였으며, 실험 결과 사용자가 요청하는 컨텐츠가 동일한 경우에는 기존 스케줄링 방식과 $13\%$ 성능 감소를 다른 경우에는 기존 스케줄링 방식보다 $102\%$의 성능 향상을 보임을 확인하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.331-340
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• 2003

Low-cost commodity SMP(Symmetric Multiprocessor) is widely used as a node of cluster system. In this paper, we implement and evaluate the performance of SDSM system for SMP clusters. Our SDSM system provides HLRC(Home-based Lazy Release Consistency) memory consistency model. Our protocol utilize shared memory within same SMP node, so that page fetch and message passing through network can be reduced. It is implemented on 8 node of 2-way Pentium-III SMP interconnected with 100Mbps Fast Ethernet, and uses TCP/IP for transport/network layer protocol. The experiment with eight applications shows that our SMP protocol achieves maximum 33% speedup improvement and 13%-52% reduction of page fetch compared with uniprocessor protocol.

• Journal of Power Electronics
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• v.10 no.6
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• pp.611-620
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• 2010

This paper presents a new architecture, called "Power Electronics Remote Wiring and Measurement Laboratory (PermLAB)", that translates a common gateway interface (CGI) string from a remote web user to a web server connected to a 3-dimension switching matrix board, can be used to switch on and off, and to control a cluster of instruments and components. PermLAB addresses real-time connection, switching, and data acquisition over the Internet instead of using simulated data. A software procedure uses a signature system to identify each instrument and component in a complex system. The Web-server application is developed in HTML, JavaScript and Java, and in C language for the CGI interface, which resides in a controller portion of LabVIEW. The LabVIEW software fully integrates the Web sever, LabVIEW data acquisition boards and controllers, and the 3-dimensional switching matrix board. The paper will analyze a half-wave rectifier (AC - DC converter) circuit connected over the Internet using the PermLAB. PermLAB allows students to obtain real data by real-time wiring of real circuits in the laboratory using a "virtual breadboard" on the Web. The software for the Web-based 3-dimensional system is flexible, portable, can be integrated into many laboratory applications or expanded, and easily accessible worldwide.

• The Research Journal of the Costume Culture
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• v.29 no.4
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• pp.603-615
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• 2021

The aim of this study was to analyze the semantic network structure of keywords and the visual composition of images extracted from Instagram in relation to the multi-persona phenomenon with in fashion imagery, which has recently been attracting attention. To this end, the concept of a 'secondary character', which forms a separate identity from a 'main character' on various social media platforms as well as on the airwaves, was considered as the spread of multi-persona and #SecondaryCharacter on Instagram was investigated. 3,801 keywords were collected after crawling the data using Python and morphological analysis was undertaken using KoNLP. The semantic network structure was then examined by conducting a CONCOR analysis using UCINET and Netdraw to determine the top 50 keywords. The results were then classified into a total of 6 clusters. In accordance with the meaning and context of the keywords included in each cluster, group names were assigned : virtual characters, relationship with the main character, hobbies, daily record, N-job person, media and marketing. Image analysis considered the technical, compositional, and social styles of the media based on Gillian Rose's visual analysis method. The results determined that Instagram uses fashion images that virtualize one's face to produce multi-persona representation s that show various occupations, describe different types of hobbies, and depict situations pertaining to various social roles.

• The Research Journal of the Costume Culture
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• v.32 no.2
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• pp.125-147
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• 2024

This study aims to analyze consumer perceptions of the metaverse platform and luxury fashion brands in relation to consumer lifestyles, thereby providing foundational data for future marketing strategies of fashion brands using the metaverse. A survey on the lifestyle and perceptions of the metaverse, as well as on luxury fashion brands, was conducted among 300 men and women between their 20s and 40s. Statistical analyses included frequency analysis, cross-tabulation, chi-square (χ²) analysis, factor analysis, cluster analysis, one-way ANOVA, and Duncan's post-hoc test. Factor analysis of the participants' lifestyles revealed five distinct types: "Indifferent," "Social, individual, and leisure-oriented," "Trend-leading and brand-oriented," "Appearance and fashion-oriented," and "Self-improvement-focused and individualistic" types. The analysis of luxury fashion brand perceptions based on lifestyle types showed that the "Trend-leading and brand-oriented" type had higher awareness and preference for brands such as Gucci, Burberry, and Balenciaga, while the "Indifferent" type showed lower levels of awareness and preference. Regarding brand perception related to luxury fashion brand content experiences within the metaverse, Gucci, Burberry, and Balenciaga showed consistent results across all types. Specifically individuals classified under the "Trend-leading and brand-oriented" category exhibited higher awareness and preference for these brands within metaverse experiences, while those categorized as "Indifferent" displayed comparatively lower levels. Therefore, digital marketing strategies targeting consumers under the "Trend-leading and brand-oriented" category are expected to be highly effective for luxury fashion brands. This study is poised to contribute to the expansion of the marketing landscape within the metaverse virtual world for fashion.