• Journal of Korea Game Society
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• v.2 no.2
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• pp.20-27
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• 2002

In this paper, I tried to propose efficient online game server architecture that decrease server overload. I used replicated distributed sever type together with non-replicated distributed sever type. Replicated distributed sever type has the advantage to maintain efficient distribution of server overload and non-replicated distributed sever type has the advantage to move a game server to a different game server freely in one server group. I used these advantages suitably in this proposal, and I will show the efficiency of online game server architecture.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.4
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• pp.137-142
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• 1999

This paper applies role-based access control(RBAC) policy for solving security problems when it will be operated business of many field on the Linux sever environments and designed RBAC＿Linux security systems that it is possible to manage security systems on the Linux environments. In this paper, the RBAC_Linux is security system which is designed for applicable on the Linux enviroment The applying RBAC model is based on RBAC96 model due to Sandhu et al. Therefor, the using designed RBAC_Linux security system on the Linux sever system have the advantage of the following: it can be implemented sever system without modifying its source code, high migration, easy and simple of secure managing.

• Journal of the Korean Statistical Society
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• v.30 no.4
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• pp.661-666
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• 2001

In this paper we consider an M/G/1 queue where the server of the system has a vacation time and the service policy is limited-1. In this system, upon termination of a vacation the server returns to the queue and serves at most one message in the queue before taking another vacation. We consider two models. In the first, if the sever finds the queue empty at the end of a cacation, then the sever immediately takes another vacation. In the second model, if no message have arrived during a vacation, the sever waits for the first arrival to serve. The analysis of this system is particularly useful for a priority class polling system. We derive Laplace-Stieltjes transforms of the waiting time for both models, and compare their mean waiting times.

• Journal of the Korean Data and Information Science Society
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• v.24 no.5
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• pp.1029-1041
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• 2013

Recently, along with emergence of big data, there are incresing demands for releasing information and micro data for public use so that protecting privacy and measuring risk of disclosure for released database become important issues in goverment and business sector as well as academic community. This paper reviews statistical methods for protecting privacy and measuring risk of disclosure when micro data or data analysis sever is released for public use.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.16-24
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• 2000

In the distributed multimedia document system, media objects distributed over a computer network are retrieved from their sources and presented to users according to specifed temporal relations. For effective presentation, synchronization have to he supported. Furthermore, presentation in distributed environments is influenced by network band with and delay, so they have to be considered for synchronization. This paper propose a distributed multimedia presentation model that supports synchronization effectively. In this model, when media objects are transfered from servers to a client, network situation and resources are monitored and thus a feedback message for change of them is sent to sever. Then, the sever adjusts the data sending rate to control synchronization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.401-404
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• 2002

최근 모자이크의 시대 이후 인터넷의 폭발적인 발달로 인해 Client-Sever의 방식의 네트웍 서비스 방식 뿐만 아니라 P2P(Peer to Peer) 등 분산 서비스 환경이 각광을 받고 있다. 사용자의 직접적인 자료의 공유를 위해서는 Peer to Peer 환경을 설정하여 분산되어진 자료의 효과적인 관리를 위한 통신의 주체가 되는 각각의 에이젼트들 간의 통신과 Sever와 Agent의 통신에 있어 악의적인 침입에 의한 정보누출이 문제가 되고 있다. 본 논문에서는 이러한 문제의 해결방안으로 P2P 환경에 적합한 PKI(공개키 기반구조)를 기반을 이용하여 보안 메커니즘을 설계하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.67-69
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• 2015

본 논문은 앱 내부결제(In-App-Purchase)에 대한 해킹 방법을 방어 할 수 있는 서버 인증 시스템 구축 및 전자 영수증의 검증항목들을 제안하고 있으며 앱의 위변조 검사를 할 수 있는 앱 무결성에 관해서도 제안하고 있다. 또한 기존의 해킹 방식이 아닌 다른 해킹 방식이 나와 보안 시스템이 공격을 받았을 경우 사후 관리 시스템인 상품 지급 내역과 결제 내역을 대조 할 수 있는 대사 시스템을 제안하고 있다. 앱 개발에 있어 내부결제 기능적 구현이 아닌 해킹 피해를 피할 수 있는 방법을 제안함으로 결제보안을 높이고자 한다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.3 no.1
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• pp.127-135
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• 1999

An inequality of Ostrowski's type for monotonous nondecreasing mappings is given. Applications for quadrature formulas are pointed out.

• Communications of the Korean Mathematical Society
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• v.18 no.1
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• pp.39-57
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• 2003

Some inequalities for the Hilbert transform of the product of two functions are given.

• Bulletin of the Korean Mathematical Society
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• v.44 no.3
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• pp.523-536
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• 2007

Sharp error estimates in approximating the Stieltjes integral with bounded integrands and bounded integrators respectively, are given. Applications for three point quadrature rules of n-time differentiable functions are also provided.