• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.290-292
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• 2012

클라우드 컴퓨팅에서는 사용량 당 과금 정책을 통해 서비스를 제공하여 사용자에게 높은 수준의 QoS 를 제공함과 동시에 비용절감의 효과를 가지고 있다. 하지만 클라우스 서비스 제공 업체에서는 최대 서비스 요구량을 만족시킬 수 있도록 시스템을 구성해야 할 필요가 있으며, 이에 맞추어 상당한 시간동안 다수의 자원을 유휴상태로 운영하여야 한다. 데이터 센터를 유휴상태로 운영될 경우 즉시 서비스 제공이 가능하다는 장점이 있으나 반대로 전력을 낭비한다는 단점을 가진다. 본 연구는 최소한의 전력소모를 하면서 QoS 를 보장할 수 있도록 하는 시스템 구축 모델을 제시하는 데 목적이 있으며 시뮬레이션 결과를 통하여 우리가 제시한 모델의 적절성을 보이려고 한다. 우리의 모델은 요청 작업 타입에 따른 traffic shaping 기법을 도입하여 작업을 저전력 컴퓨터와 고성능 컴퓨터에 분산배치하도록 하는데 목적이 있으며 가상화 기법을 통해 작업의 신속한 분산작업을 수행하는 방법을 사용한다.

• Proceedings of the Korean Society for Information Management Conference
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• 2018.08a
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• pp.91-96
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• 2018

교육의 국제화로 인해 국내 대학에 재학 중인 유학생의 수가 매년 증가하고 있다. 그러나 유학생들이 학습 자원을 얻기 위한 가장 큰 정보원인 대학도서관은 유학생들을 위한 다국어 지원 서비스를 충분히 제공하고 있지 않은 상황이다. 따라서 본 연구에서는 대학도서관에서 제공하는 서비스 중 다국어 지원이 가능한 서비스 요인들을 선정하고 해당 요인들이 유학생들의 대학도서관 이용 만족도에 미치는 영향을 파악하고자 하였다. 이를 위해 먼저 선행연구를 바탕으로 사서/직원의 서비스(응답능력, 태도), 도서관 시설 이용(시설 안내, 장비 사용), 자료 접근 및 이용(홈페이지, 서가 배치), 이용자 서비스(이용자교육, 기타서비스)를 요인을 도출하였고 회귀분석을 실시하였다. 연구 결과에 따르면 도서관 시설 이용이 대학도서관 이용 만족도에 가장 큰 영향을 미치고 있었으며 사서/직원의 서비스와 이용자 서비스 또한 영향을 미치는 것으로 나타났다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.517-520
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• 2013

센서 네트워크는 수많은 센서 노드들로 구성되는 네트워크이다. 각 센서 노드는 배치된 환경에서 정보를 수집하여 전송하는 동작을 한다. 하지만 정보 전송 시에 공격자에게 노출되어 정보가 공격당할 우려가 있기 때문에 안전한 통신을 위해서 키 관리 기법이 필요하다. 그러나 센서 노드의 특징인 제한적인 자원을 가지고 있다는 점 때문에 공개키 알고리즘을 적용하기 어렵고 또한 다른 키 관리 기법에도 제약 조건이 따른다. 이러한 센서 네트워크의 특징을 고려하여 기존에 연구된 키 관리 기법들을 보완할 효율적이고 안전한 키 관리 기법을 제안하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.37-39
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• 2022

KISTI(한국과학기술정보연구원)는 슈퍼컴퓨터 5호기 메인시스템인 Nurion과 보조시스템인 Neuron을 연구자들에게 서비스하고 있다. Neuron은 메인시스템인 Nurion이 Intel Knights Landing 프로세서가 장착된 클러스터로 구성됨에 따라 인공지능, 빅데이터에 관한 연구 인프라 수요를 충족시키기 위해 GPU를 장착한 이기종 클러스터로 구성되어 있다. Neuron은 연구자들에게 효율적으로 계산 자원을 배분하기 위해 SLURM 작업배치스케줄러의 공유노드 정책을 이용하여 한 개의 계산노드에서 다수 개의 작업이 수행될 수 있는 환경으로 서비스되고 있다. 본 논문에서는 공유노드 정책으로 운영 중인 클러스터 시스템에서 작업별로 GPU 사용 통계 데이터를 생성하는 기법을 소개한다.

• Korean Journal of Social Welfare
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• v.36
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• pp.101-127
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• 1998

The purpose of this study is to develop human resources and management system model for home-based welfare services. For the purpose of the study, both of method of literature review about home-based welfare services and previous research and survey were used in the study. The subjects of the survey were Junior and senior high school students, the employed, housewives, the disabled, and the aged. They were considered as human resources for the home-based welfare services. Based on the result of the survey and related theories, the study suggests the model for the development of volunteers and management system composed of recruitment, education and training, disposition, management and supervision, and evaluation for home-based welfare services. Assuming linking and cooperation between volunteer center and agency using volunteers which provide home-based welfare services, the model was developed. The role of volunteer center is recruitment, education and training. The agency using volunteers is responsible for education, disposition, supervision, and evaluation related to practice. In the stage of recruitment, elaborating strategy considering characteristics of group was suggested. In the campaign, use of mass media, selection of timing, equal opportunity for all group were suggested. Also outreach strategy as a effective recruitment strategy was presented. In the stage of education and training, method and content of education in each stage of primary education and re-education were presented. In the stage disposition, method and content for the right volunteer in the right place were suggested. In the stage of management and supervision, supervision by coordinator and necessity of using volunteers as para-professionals was suggested. Also the necessity of program operation for volunteer maintenance and management was discussed. In the stage of evaluation, time, main body, and method of evaluation was suggested.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.67-76
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• 2020

With the fast development in wireless communications and vehicular technologies, vehicular ad hoc networks (VANETs) have enabled to deliver data between vehicles. Recently, VANETs introduce a Vehicular Cloud (VC) model for collaborating to share and use resources of vehicles to create value-added services. To construct a VC, a vehicle should search vehicles that intend to provide their own resource. The single-hop search cannot search enough provider vehicles due to a small coverage and non-line-of-sights of communications. On the other hand, the multi-hop search causes very high traffics for large coverage searching and frequent connection breakages. Recently, many Roadside Units (RSUs) have been deployed on roads to collect the information of vehicles in their own coverages and to connect them to Internet. Thus, we propose a RSU-aided vehicular resource search and cloud construction mechanism in VANETS. In the proposed mechanism, a RSU collects the information of location and mobility of vehicles and selects provider vehicles enabled to provide resources needed for constructing a VC of a requester vehicle based on the collected information. In the proposed mechanism, the criteria for determining provider vehicles to provide resources are the connection duration between each candidate vehicle and the requester vehicle, the resource size of each candidate vehicle, and its connection starting time to the requester vehicle. Simulation results verify that the proposed mechanism achieves better performance than the existing mechanism.

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.109-122
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• 2018

The composite lognormal-generalized Pareto distribution (LN-GPD) is a mixture of right-truncated lognormal and GPD for a given threshold value. Scollnik (Scandinavian Actuarial Journal, 2007, 20-33, 2007) shows that the composite LN-GPD is adequate to describe body distribution and heavy-tailedness. This paper considers time-varying modeling of the LN-GPD based on local polynomial maximum likelihood estimation. Time-varying model provides significant detailed information of time dependent data, hence it can be applied to disciplines such as service engineering for staffing and resources management. Our work also extends to Beirlant and Goegebeur (Journal of Multivariate Analysis, 89, 97-118, 2004) in the sense of losing no data by including truncated lognormal distribution. Our proposed method is shown to perform adequately in simulation. Real data application to the service time of the Israel bank call center shows interesting findings on the staffing policy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.211-212
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• 2016

It is important to adopt an operation system to operate the Automated warehouses using limited resources such as space, mobile racks, and forklift. The main purpose from the operation system is to reduce the length of moving and time for both mobile racks and forklift. The complexity of the warehouse will be higher because the racks and vehicles are moving at the same time. This complexity influences badly so the operation system has to control it well. Not only layout or receipt or issue, but also conflict between mobile racks and vehicles give more complexity to the warehouse. This paper aims to fine the proper operation method related to the layout and the cargo assignment.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.17-24
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• 2012

As the resources and power on Ad-hoc networks are limited, new data aggregation techniques are required for energy efficiency. The current research on data aggregation techniques is actively in progress, but existing studies don't consider the density of nodes. If nodes are densely placed in a particular area, the information which the sensor nodes placed on those areas detect can be judged as very strong association. But, the energy spent transmitting this information is a waste of energy. In this paper the densely-concentrated node area is designated as Hotspot_Zone in the multi-hop clustering environment using the AMC and a key node is selected in the area. If the request message of data aggregation is transmitted, the key node among the neighboring nodes sends its environmental information to a manager to avoid duplicate sensing information. Therefore, the life of networks can be prolonged due to this.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.758-766
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• 2011

Cooperative communications are adopted as a promising solution to achieve high data rate over large areas in the future 40 wireless system and the relay station (RS) is the key concept in cooperative communications. However, most existing works in this area focus only on optimal RS selections. In addition, there are only few works consider another crucial issue: how many relay stations we need to place. Only when the number of relay stations is defined, the relay station selection can be performed well. In this paper we derive a formula which describes the impact of varying number of RS on end-to-end link throughput assuming a clustering scheme which is based on Voronoi tessellation. In addition to mathematical analysis on the feasibility of the formula, we also examine its performance through a set of simulations under the Erceg path loss model. Simulation results verify that the link throughput gain of our proposed scheme is promising.