• Annual Conference of KIPS
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• 2020.11a
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• pp.830-833
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• 2020

콜센터에서 인력 스케줄링은 매우 중요하다. 모든 콜센터에서 인건비는 고정비 성격이 강하여 차지하는 비중이 매우 높아 콜센터의 이익을 좌지우지한다. 그렇기 때문에 콜센터의 적정 인력의 고용과 배치는 인건비 뿐만 아니라 콜 성공률 또한 직결되어 있어 콜센터 운영에서 중요한 사안이라고 할 수 있다. 대부분의 콜센터가 현재까지도 관리자의 경험에 의해 인력배치를 수립하는데, 이러한 방법은 과학적이지 않으며 인원수에 영향을 미치는 모든 변수들을 고려할 수 없다. 과거 수학적 모델을 수립하는 것이었다면, 지금은 모델을 학습시키고, 학습된 모델을 기반으로 미래의 고객과 인원수를 예측해야 한다. 본 논문에서는 수리제약식을 통해 다양한 변수들을 고려하고 비선형 정수 계획법과 딥러닝 기반의 예측 값을 이용하여 비선형 정수계획법을 통해 최적의 인력배치 스케줄링을 수립하였다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.194-202
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• 2016

This study aims to review a topology optimization based on finite element analysis (FEA) for conceptual design of platform in the 10MW class floating type wave-wind hybrid power generation system (WHPGS). Two topology optimization theories, density method (DM) and homogenization design method (HDM) were used to check which one is more effective for a simplified structural design problem prior to the topology optimization of platform of WHPGS. From the results of the simplified design problem, the HDM was applied to the topology optimization of platform of WHPGS. For the conceptual platform design of WHPGS, FEA model was created and then the structural analysis was performed considering offshore environmental loads at installation site. Hydrodynamics analysis was carried out to calculate pressure on platform and tension forces in mooring lines induced from the offshore environmental loads such as design wave and current. Loading conditions for the structural analysis included the analysis results from the hydrodynamic analysis and the weights of WHPGS. Boundary condition was realized using inertia relief method. The topology optimization of WHPGS platform was performed using the HDM, and then the conceptual arrangement of main structural members was suggested. From the results, it was confirmed that the topology optimization might be a useful tool to design the conceptual arrangement of main structural members for a newly developed offshore structure such as the floating type WHPGS.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.51-58
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• 2010

Wireless Mesh Network has drawn much attention due to wide area service coverage with low system cost. However, there is a bottleneck problem in wireless mesh network since the traffic is aggregated into a gateway. Placement of multi-radio can easy the bottleneck problem, but without careful design it results in unnecessary system cost increasement. In this paper, we propose a system cost minimization through differential antenna placement where optimum antenna placement is determined by the required wireless link capacity. With CPLEX program, optimum number of antennae is determined as a function of local user traffic and gateway capacity. From numerical analysis, it is confirmed that our proposed model can solve bottleneck problem, and at the same time save the system cost.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.483-484
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• 2013

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.240-244
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• 1997

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.106-110
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• 2008

The requirement for customized learning environments is increasing with the development of Web 2.0 technology To personalize services in E-learning, there are various functions available to the user. However, some components have fixed or inflexible functionality that limits what can be changed, and customization information has not been used for other purposes. In this paper, we propose an e-Space manager for the dynamic customization of learning environment control units. The proposed method can confirm which areas users have customized and how they have customized them. The advantage is that users can control their own learning environments, including not only the format, but also the content within the limits of the underlying system. The customization information is captured to confirm the competency model.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.35-40
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• 2013

In the eLoran navigation system, the dominant deterioration factors of navigation accuracy are the TOA measurement errors on user receiver and the GDOP between the receiver and the transmitters. But if the ASF data measured at dLoran reference station are provided for users through the Loran data channel, it will be possible to correct the TOA measurement errors. The position accuracy can be determined by the DOP depending on the geometry of receiver-transmitters, and their optimal placement improves the navigation accuracy. In this study we determined the geometric placement in case of up to six stations, and evaluated the performance of position accuracy for the receiver-transmitter geometry set of eLoran stations. The proposed geometry of eLoran stations can be referred for the construction of eLoran infrastructure meeting the capability of HEA for maritime, and time/frequency users in Korea.

• Journal of IKEEE
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• v.11 no.3
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• pp.100-107
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• 2007

One of the fundamental problems in wireless sensor networks is the efficient deployment of sensor nodes. The Fuzzy C-Means(FCM) clustering algorithm is proposed to determine the optimum location and minimum number of sensor nodes for the specific application space. We performed a simulation and a experiment using two rectangular and one L shape area. We found the minimum number of sensor nodes for the complete coverage of modeled area, and discovered the optimum location of each nodes. The real deploy experiment using sensor nodes shows the 94.6%, 92.2% and 95.7% error free communication rate respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6A
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• pp.417-424
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• 2011

This study focused on development of 60 m span PSC girder considering not only structural performance, but also economical efficiency and constructability including from the improvement of cross-section to the tendon profiles in sequence. Bulb-T type cross section was derived from optimization and actual possibilities to design a bridge were assessed through cross section evaluation. Tendons were also arranged efficiently so that the girder could resist the service load effectively. After developed girder was applied to a sample bridge, result of finite element analysis proved all load steps were satisfied with the allowable stress. Furthermore, it seemed that sufficient redundancy will be available to design a bridge safely. Based on these, a full-scale 60 m span girder was fabricated and 4 point bending test was performed. An initial crack occurred over twice of the service load in this experiment, which establishes adequate structural performance. 60 m span Half-Decked PSC girder developed in this study has a lower height for the given span which resulted from cross section improvement and efficient tendon layout. This girder also has not only the structural advantage, but also advantages in economical efficiency and constructability.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.393-403
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• 2021

Recently, there is becoming larger interest in the public practice centers equipped with advanced manufacturing equipment of industries that is difficult to have in all vocational high schools for strengthening practical education and technical education tailored to the Fourth Industrial Revolution in vocational high schools. In this study, using spatial optimization approaches, we explored the optimal location sets of the public practice centers of vocational high schools in Seoul for an illustration. For the proposed optimial location methods, P-median Problem (PMP) and Maximal Coverage Location (MCLP) were used because, when the public practice centers located in priority of large vocational high schools based on the number of students, it showed that the result is not minimizing the travel distance and maximizing the demand of the vocational high school students. This study found that the PMP can find the optimal location sets that minimize the travel distance of whole students. In addition, all students can be captured through locating five public practice centers by MCLP. It should be noted that the optimal locations of this study are limited in Seoul. However, the frame of this methodology applied in this study can be utilized to locate the public practice centers in other regions based on the spatial decision making.