• 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 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.

• 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 Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1501-1505
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• 2004

The authentication system of high-speed internet in IP-infra is not warm enough to administration of systematic authentication information for user's legalization, connection right and resources allocation in order to both methods of authentication-unauthentication connection system according to transmission method . Also unauthentication connection raises a difficulty condition to user's needs satisfaction in order to a load weighting of system and network and a drop of transmission speed. Accordingly, this study brings forth authentication system construction in a high-speed IP infrastructure using spam sever able to construct the suitable network condition according to unifying authentication-unauthentication system for single authentication system.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.524-529
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• 2004

In this paper, We described the method which developed the optimal control system for air separation unit to change production rates frequently and rapidly. Control models of the process were developed from actual plant data using subspace identification method which is developed by many researchers in resent years. The model consist of a series connection of linear dynamic block and static nonlinear block (Wiener model). The model is controlled by model based predictive controller. In MPC the input is calculated by on-line optimization of a performance index based on predictions by the model, subject to possible constraints. To calculate the optimal the performance index, conditions are expressed by LMI(Linear Matrix Inequalities).In order to access at the Bailey DCS system, we applied the OPC server and developed the Client program. The OPC sever is a device which can access Bailey DCS system.The Client program is developed based on the Matlab language for easy calculation,data simulation and data logging. Using this program, we can apply the optimal input to the DCS system at real time.

• 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 Society of Precision Engineering Conference
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• 1995.10a
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• pp.885-888
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• 1995

Virtual Manufacturing System(VMS) is a computer model that represents the precise and whole structure of manufacturing system and simulates their physical and logical behavior in operation. In this paper, a real time simulation for the virtual factory is proposed to integrate a process planning with scheduling under distributed environments. In order to communicate the information under distributed environment, weuse a sever/client concept and socket program. the VMS is implemented on the internet environment.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.199-206
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• 1997

Under sever earthquake, structural elements or structures may sustain a large number of inelastic excursions. To predict seismic damage of the structures with accuracy, much research for general definition of structural collapse and seismic damage analysis is required. The ductility method, the energy method and Park and Ang method for seismic damage analysis of structural elements and structures are compared in this paper. Also, the seismic damage analysis for system-level of structure is carried out using the ESDOF-system method and Powell method. To compare tendency of the seismic damage analysis using each methods, example analysis is accomplished for several cases of different structures and different earthquake excitation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1208-1213
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• 2006

A micro embedded did the task to be simply the sequent at the past. The necessity of an embedded operating system did not exist in the reason. We satisfy the complication of the system and operating system have been desired for the officer of the process. The necessity of the process of real-time processing increased also with fast response time to users, The porting follows and have been composed of an real-time embedded operating system. We can control the control unit with the sensor to be established in the building, An embedded web sever to use the resource of the at least is appering a networking facility of interaction. In this paper, The web sever to be implemented in a purity software. We draw data for the thing to implement overall demo to the remote through Internet and We put the point even though we organized the frame to control this. we have successfully ported linux on an embedded system, which is based on intel StrongARM SA-1110 processor, then written several network modules of ethernet-based network device.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.161-168
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• 2018

In this study, IT based traceability system which is able to measure weight and moisture content of grain in the post-harvest process of intake, drying, storage and milling was developed in RPC(Rice processing complex). Measured information of weight, moisture content, yield, loss and quality was saved in the DB sever. Simultaneously, lot No. was generated and connecting to quality and traceability information. Also, automatic control system with MMI(Man Machine Interface) and yield and inventory control system(YICS) for grain was developed for the traceability system by applying the TCP/IP communication. In addition, simulation of system was performed for evaluation in RPC.