• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.1-10
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• 1995

In this study, a threshold policy is considered for the M/M/2 queueing system with server vacations. The probability generating function for the number of customers present in the system is derived using an embedded Markov chain approach. Then, assuming a linear cost structure, an efficient procedure to find an optimal threshold policy is presented. The Laplace-Stieltjes transofrm for th waiting time of an arbitrary customer under a "FIFO" discipline is also derived.o derived.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.665-666
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• 2015

Recently BIM technology has been expanded for using in construction project. However its spread has been delayed than the initial expectations, due to the high-cost of BIM infrastructure development, the lack of regulations, the lack of process and so forth. In construction site phase, especially the analysis of current research trend about IT technologies, virtualization and BIM service, data exchange such as drawing, 3D model, object data, properties using cloud computing and virtual server system is defined as a most successful solution. The purpose of this study is enable the cloud computing BIM server to provide several main function such as edit a model, 3D model viewer and checker, mark-up, snapshot in high-performance quality by proper design of VDI system. Concurrent client connection performance is a main technical index of VDI. Through test-bed server client, developed VDI system's multi-connect control will be evaluated. The performance-test result of BIM server VDI will effect to development direction of cloud computing BIM service for commercialization.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.58-61
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• 2003

This paper proposes e-Learning environments far digital circuit experiment. The e-Learning environments are implemented as a WBT system that includes the circuits monitoring system and the students management system. In the WBT client-server system, the instructor represents the server and students represent clients. The client computers are equipped with a digital circuit training board and connected to the server on the World Wide Web. The training board consists of a Programmable Logic Device (PLD) and measuring instruments. The instructor can reconfigure the PLD with various circuit designs from the server so that students can investigate signals from the training board. The instructor can monitor the progress of the students using Joint Test Action Grouo(JTAG) technology. We implement the WBT system and a courseware fo digital circuits and evaluation the environments.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.55-60
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• 2014

Today, there is increasing the elderly population in rural community, and people of returning from the urban to the rural community are demand to be of high value-added agriculture. In this time, there are required to regularization, standardization, automation, for getting of production of high value crops. In this paper, we are study for automation cultivation control system design for produce high-value crops. this system were designed of two parts that one part is measure and control unit, another part is server part for database and server side control. the main controller for measurement and control is used MC9S08AW60, server for Database and server-side control was using MySQL with CentOS. The source code of control program was coding C and compile with GCC. the functions of measurement and control unit are digital input and output each 8channels and can be scan-able of 20 Bit with 2CH/Sec. Analog Output were designed that can be output of 4-20mA or 0-5V on 4channel. The Digital input and output part were designed 8-channel, and using the high speed photo coupler and relays. We showed that system is possible to measure a 20bit data width, 2Ch/sec as 8 channel analog signals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3C
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• pp.233-240
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• 2012

Unlike traditional factory environment, in an industrial factory network applied wireless sensor network technologies, all procedures of discovery, identification and verification of devices should be performed in an automatic fashion. To address these challenges, we design a management system using the device registry server that we propose in this paper. In the phase of device discovery, the proposed system utilizes properties of routing protocol running in factories. Also, in the phase of identification and verification, the system uses unique and general information of a device stored within the device registration server. Such a way allows management system to reduce implementation complexity and to easily manage devices in a factory applied with a wireless network consisting of heterogeneous devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.74-80
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• 2002

As "Nationwide Educational Information System", as one of 11 essential tasks of the electronic government, is to be introduced step by step from March in 2003, the current School Information Management System servers in each school cannot be functioned appropriately any more. Management of school cumulative records will be done by the integrated server of the regional Office of Education. Accordingly, more than 20,000 servers of various kinds available in each school should be put into use in one way or another. So this thesis aims to suggest how to reuse these servers in schools, and how to approach modeling of the 21st-century school in the School Information Management System.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1513-1518
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• 2007

This paper describes a design and implementation of diabetes management system based on PDA in the wireless Internet. Our system is a 3-Tier Client/Server model with client, server, middleware, and DB. The client has each PDA for patients and for doctors related to diabetics. The one is used for patients to manage this disease by themselves with, and the other is used for the doctors to monitoring the patients' data with. The server receive the daily data measured by the patients through wireless network, middleware mediate between an client(PDA) and server. As the result of implementation of the system, we expected that it manages to diabetic patients continually and systematically.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.153-158
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• 1995

보 및 평판의 진동에 대해서 에너지의 손실은 재료감쇠를 이용한 표면감쇠처리나 지지부에서의 감쇠처리에 의하여 증가될 수 있다. 감쇠재료를 이용한 표면감쇠처리의 예로서 보/평판 표면에 접착되는 감쇠 테이프나 코팅등은 아주 효과적임이 입증되었다. 마찬가지로 지지부 감쇠처리는 점탄성재료의 삽입에 의해서 설명될수 있다[1]. 보/평판의 감쇠에 대한 최근의 많은 연구들은 진동하고 있는 보/평판의 표면에 적용하는 감쇠 테이프 혹은 적층형태의 감쇠 처리방법에 대해서 주로 수행되었다. 일반적으로 표면감쇠처리방법은 진동감소에 아주 효과적이지만 실제 적용상에서 항상 가능한 것은 아니며, 이와 같은 경웨는 지지부 감쇠 처리방법에 의존하게 된다[2]. 감쇠특성을 갖는 점탄성재료를 실제로 적용할 때 보/평판의 유한한 길이가 점탄성재료로 지지되며 점탄성재료의 물성치와 치수에 따라서 계의 모우드 매개변수(고유진동수, 계의 손실계수 그리고 모우드형상)가 크게 달라진다. 그리고 이와 같은 계에 대해서는 지지부의 거동보다는 전체 시스템의 고유진동수와 손실계수 그리고 보 영역에서의 모우드 형상에 더 관심이 있으므로 지지부 영역을 집중매개변수(lumped parameter)로 나타내어 계를 해석할 수 있다. 일반적으로 보와 평판의 경계에서는 병진 및 회전방향의 강성 뿐만 아니라 두 강성사이에 연성효과도 동시에 발생하게 되므로 이 항을 고려하여 계를 모델링해야 한다. 본 연구에서는 우선 점탄성 재료에 의한 지지부영역의 등가 강성계수들을 구하고 경계에 강성행렬을 갖는 보의 등가시스템을 얻는다. 그리고 등가시스템의 주파수방정식으로부터 모우드 매개변수에 대한 지지부의 영향을 살펴본다. 또한 시스템이 비교적 복잡한 사각 평판의 진동에 대해서도 동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed database system) and the data management method through a distributed database system where complete responsi

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.37-46
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• 2005

In Processing many operations based on distributed environment, it is very important to support the reliability of resources. Providers of resources generally adapt the structure of server-replication to support the reliability of services. Tn server side, it maintains replicas. duplicated server objects. In the structure of this replication, service of stable replica is very important. Therefore the structure to diagnosis the fault of such replica is required. In this Paper, we suggested an effective PUSH fault management algorithm based on PUSH monitoring style of CORBAto overcome weak points of the PULL monitoring style of the replication management system in the distributed object system. Outcomes of the suggested PUSH fault monitoring style were better than other system. We confirmed valuable result in the workloads and timeout-rates.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.31-40
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• 2020

As a result of reenforcement of livestock industry licensing and livestock related vehicle registration system, pig farm are mandatory for setting stop bar before pig farm entrance and maintaining the records of inlet and outlet to and from pig farm. Also, the first step to the pig farm biosecurity is the control of entrance human, vehicles, animals and the related records including entrance and sterilization. In this study, the pig farm entrance control system using RFID technology and web-server system was developed. For human entrance, contact type RFID reading system(13.56MHz) was developed. And the 900MHz RFID system was used to detect vehicle entrance. The test result shows that system actuating, recognition, saving records to the web server was successful. Then, the full system of human entrance recording unit, vehicle entrance recording unit, entrance control system, human sterilizing booth containing a tablet for inputting visitor's record and sterilization record was tested. The records were wrote to web server DB through the data management web-program. Performance test shows the entrance control and data management in server was successfully operated.