• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.2
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• pp.119-131
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• 2008

The paper considers the computation method in the performance evaluation of cellular network in the phase-type distribution assumptions that the channel holding times induced from mobility are modeled by well-fitted distributions to reflect an actual situation. When ww consider a phase-type distribution model instead of exponential distribution, the complexity of the computation increase exponential even though the accuracy is improved. We consider an efficient numerical algorithm to compute the performance evaluations in cellular networks such as a handoff call dropping probability, new call blocking probability, and handoff arrival rate. Numerical experiment shows that numerical analysis results are well approximated to the results of simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.115-118
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• 2012

현재 서비스 산업에서는 급변하는 고객의 욕구를 맞추기 위해 기업 간의 서비스 경쟁 심화 및 다양한 각도에서의 최상의 고객서비스를 제공하기 위한 노력이 지속적으로 시도되고 있다. 서비스 종사자들도 기업과 고객이 기대하는 고객 중심 서비스 제공에 기여하고 있다. 과도한 서비스 제공은 서비스 종사자의 감정적 스트레스 등과 같은 부작용을 발생시키고 있는데, 기업과 고객과의 접촉 채널로서의 중요한 역할에 임하는 콜센터 상담사들의 스트레스 해소는 업무 향상에 있어서 필요하다. 스트레스 해소를 위한 정신적인 긍정어 즉, 역경을 이겨내는 긍정의 힘이 '회복탄력성'으로서, 콜센터 상담사의 회복탄력성을 분석한 결과 근무경력과 업무 유형에 따라 차이를 보였다. 회복탄력성의 구성요소 중 감정통제력, 충동통제력, 원인분석력, 공감능력, 자기효능감은 근무경력에 따라 차이를 보였고, 낙관성, 공감능력은 업무 유형에 따라 차이가 나타났다.

• Asia Marketing Journal
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• v.8 no.3
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• pp.1-11
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• 2006

The Bass model assumes two communication channels: mass-media and word-of-mouth. In this paper, we call the mass-media Type I channel of communications. The word-of-mouth channel means interaction between non-adopters and adopters. Let us call it Type II channel of communications. In the real world, however, the non-adopters who are not aware of the innovation can be affected by communications with other non-adopters who are aware of it. Let us call it Type III channel of communications to differentiate with Type II channel. This paper analyzes the impact of Type III channel on diffusion process. The result shows that exponential growth patterns (for example, the adoption patterns of the blockbuster movies) can be observed when non-adopters are influenced by other non-adopters who aware of the innovation.

• The Zoological Society Korea : Newsletter
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• v.12 no.2
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• pp.85.1-85
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• 1995

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.131.1-131
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• 1995

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.565-572
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• 2007

3G Long Term Evolution (3G LTE) is a next generation cellular networks system capable or providing various mobile multimedia services by using OFDMA and MIMO based radio access technology. Among many differences from existing WCDMA based systems, the facts that 3G LTE uses Physical Resource Block (PRB) as its radio resources and provides all services through the PS domain make the development of new resource management schemes necessary. This paper proposes an adaptive partitioning based downlink call admission control scheme. It separates realtime call requests from non-realtime ones, specifies maximum allowable resource amounts for each type, but if the maximum is exceeded, call requests are accepted with probability proportional to remaining resource amounts. Despite the fact that such adaptive concept has been already adopted by other call admission schemes, the contributions of our paper, which are that we are able to find an efficient way to apply the proposed scheme exploiting PRB characteristics and measure the resource usage of base stations by PRB utilization and payload ratio, are still valid. When judging from simulation results in comparison with others, our scheme is able to prioritize realtime call requests over non-realtime ones, and at the same time, overall system performance is superior.

• Journal of the Korean Statistical Society
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• v.36 no.3
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• pp.335-347
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• 2007

Two new types of positive biasedness, which are closely related to Type III positive biasedness (Yanagimoto and Sibuya, 1972), are proposed. We call these near Type III positive biasedness. Though no implication between Type II and near Type III biasedness exists, near Type III seems to be less restrictive than Type II biasedness. Constrained maximum likelihood estimates of distribution functions under near Type III positive bisedness are obtained. The likelihood ratio tests of symmetry against new positive biasedness restrictions are proposed. A small simulation study is conducted to compare the performance of the tests.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.461-473
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• 2003

Multimedia applications are much more sensitive to QoS(Quality of Service) than text based ones due to their data continuity. In order to provide a fast moving MH(Mobil Host) using multimedia application with a consistent QoS,an efficient call admission mechanism is in need. This paper proposes the 2SCA(2-Step Call Admission) scheme based on cal admission scheme using pripority to guarantee the consistent QoS for mobile multimedia applications. A calls of MH are classified new calls, hand-off calls, and QoS upgrading calls. The 2SCA is composed of the basic call admission and advanced call admission; the former determines the call admission based on bandwidth available in each cell and the latter determines the call admission by applying DTT(Delay Tolerance Time), PQeueu(Priority Queue), and UpQueue(Upgrade Queue) algorithm according to the type of each call blocked at the basic call admission stage. In order to evaluate the performance of our mechanism, we measure the metrics such as the dropping probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The result shows that the performance of our mechanism is superior to that of existing mechanisms such as CSP(Complete Sharing Policy), GCP(Guard Channel Policy) and AGCP(Adaptive Guard Channel Policy).

• Bulletin of the Korean Mathematical Society
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• v.56 no.2
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• pp.351-364
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• 2019

We derive full closed-form expressions for the prices of European symmetric power quanto call options with four different forms of terminal payoffs under the assumption of the classical lognormal asset price and exchange rate model.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.698-712
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• 2004

DiffServ network architecture does not define a call admission control procedure explicitly. In this paper, a new DiffServ QoS control mechanism is suggested which, after the call admission control, can execute packet process according to the class while, at the same time, executing on the flow based call admission control in the DiffServ network. Routers on the path from the source to the destination estimate the aggregated class traffic of the existing flows and the new incoming flow and then, perform a call admission control in accordance with the type of classes efficiently based on the required bandwidth per each class that can meet the user's QoS requirements. In order to facilitate the packet process according to the class after the flow based call admission control, a mechanism is suggested that can adjust the network resources to classes dynamically. The performance analysis on this mechanism is carried out through a simulation.