• International Commerce and Information Review
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• v.3 no.1
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• pp.7-24
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• 2001

많은 기업들이 e-Business를 적극 추진하고 있으나, 기대한 만큼의 경영성과를 올리고 있는 기업은 거의 없는 실정이며, 더 나아가 e-Business의 회의론까지 대두되고 있는 실정이다. 그럼에도 불구하고 e-Business는 Product & Service Leadership, Operational Excellence, Customer Intimacy 확보 차원에서 지속적으로 성장할 것으로 예상된다. 따라서 Off-line 기업의 IT 설비투자 확대, Off-line 기업과 온라인 기업간의 적절한 조화, 기업간 협력 활성화, 닷컴 기업의 경쟁력 확보 등이 갖춰지면 e-business는 향후 우리에게 새로운 도전과 기회를 제공할 것이다.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.288-290
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• 2004

Networked Digital Recorder(NDR) Platform is a system that owns contents jointly between tv viewers connected by the broadcast broadband convergence network. NDR suggests a new content distribution chain model that users can receive broadcast contents, share contents and sends contents by convergence network. This paper looks at the system requirements, service model and the overall system architecture of NDR platform.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.3
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• pp.32-37
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• 2004

This paper investigates the mathematical model of multi-server retrial queueing system with the Batch Markovian Arrival Process (BMAP), the Phase type (PH) service distribution and the finite buffer. The sufficient condition for the steady state distribution existence and the algorithm for calculating this distribution are presented. Finally, a formula to solve loss probability in the case of complete admission discipline is derived.

• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.827-837
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• 1998

We consider the M/G/1 queue with instantaneous feed-back. The probabilities of feedback are determined by the state of the underlaying Markov chain. by using the supplementary variable method we derive the generating function of the number of customers in the system. In the analysis it is required to calculate the matrix equations. To solve the matrix equations we use the notion of Ex-tended Laplace Transform.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.211-217
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• 2015

A dynamic spectrum access scheme with channel partitioning for secondary handover calls in cognitive radio networks is proposed to reduce forced termination probability due to spectrum handover failure. A continuous-time Markov chain method for evaluating its performance such as blocking probability, forced termination probability, and throughput is presented. Numerical and simulation results are provided to demonstrate the effectiveness of the proposed scheme with channel partitioning.

• Safety and Health at Work
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• v.12 no.1
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• pp.133-135
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• 2021

The COVID-19 pandemic has resulted in movement restrictions being instituted globally and the cessation of work at many workplaces. However, during this period, essential services such as healthcare, law enforcement, and critical production and supply chain operations have been required to continue to function. In Singapore, measures were put in place to protect the workers from infection at the workplace, as well as to preserve the operational capability of the essential service in a COVID-19 pandemic environment. This paper critically analyses the measures that were implemented and discusses the extension to broader general industry.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.181-194
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• 2020

Due to the changes in the distribution market, issues related to storage and distribution of agricultural, aquatic and livestock products, and storage and transportation of processed and fresh food are rapidly emerging, and as a result, Cold Chain is naturally receiving attention as one of the logistics services. The purpose of this study is to evaluate the competitiveness of location in the construction of a cold chain cluster centered on the metropolitan area, which has attracted attention in relation to the distribution of cold chains, such as recently refrigerated frozen foods. To this end, this study evaluated the competitiveness of cold chain cluster candidates in the metropolitan area by utilizing the CFPR (Consistent Fuzzy Preference Relations) method that can efficiently extract and quantify expert knowledge. As a result, the location competitiveness was found to be superior to Incheon New Port's hinterland, Gyeonggi South Area (Yongin), Gyeonggi West Area (Gimpo Logistics Complex), and Pyeongtaek Oseong Logistics Complex. In particular, this study extracted the knowledge of refrigerated and refrigerated logistics warehouse operation experts, and conducted detailed competitiveness assessments for cold chain cluster candidates in the metropolitan area, and suggested the optimal cluster candidates. In the future research, it is necessary to classify the questionnaire into the owner, large business group, and public business group, etc., who have the right to purchase and build to secure ownership of the fresh food distribution center.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.83-88
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• 2008

In total, 1,142 serum samples were collected from 223 goat flocks rising in five different regions of Korea. These samples were screened for the presence of border disease virus (BDV) antibodies using an enzyme linked immunosorbent assay. Of the 1,142 samples, we found 47 bovine viral diarrhea virus (BVDV) positive cases (4.1%). These positive serum samples were also examined further by using the virus neutralization test against BDV. In addition, samples were tested for both BVDV and classical swine fever virus (CSFV). All of the samples that were seropositive for BDV also demonstrated positive antibody titers against BVDV and CSFV. Due to their common antigenicity, we also determined further the prevalence and carried out virus neutralization test against three pestiviruses: 314 of the goat samples were screened using reverse transcription polymerase chain reaction with primer pairs specific to common pestivirus genome regions. Overall, 1.6% (5/314) of the samples tested was positive for pestivirus. Based on the nucleotide sequence data and the phylogenetic analysis, three isolates were characterized as BVDV type 1 and two isolates as BVDV type 2. However, none of the isolates could be classified as BDV. These results indicate that BVDV-1 and BVDV-2 are the pestivirus strains circulating among Korean goat populations.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.125-133
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• 2008

In this paper, we propose active queue management mechanism (Active-WRED) to guarantee quality of the high priority service class in multi-class traffic service environment. In congestion situation, this mechanism increases drop probability of low priority traffic and reduces the drop probability of the high priority traffic, therefore it can improve the quality of the high priority service. In order to analyze the performance of our mechanism we introduce the stochastic analysis of a discrete-time queueing systems for the performance evaluation of the Active Queue Management (AQM) based congestion control mechanism called Weighted Random Early Detection (WRED) using a two-state Markov-Modulated Bernoulli arrival process (MMBP-2) as the traffic source. A two-dimensional discrete-time Harkov chain is introduced to model the Active-WRED mechanism for two traffic classes (Guaranteed Service and Best Effort Service) where each dimension corresponds to a traffic class with its own parameters.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.