• Journal of the Korean Statistical Society
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• v.29 no.4
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• pp.473-488
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• 2000

We consider a Markovian retrial queue with waiting space in which the service rates and retrial rates depend on the number of customers in the service facility and in the orbit, respectively. Each arriving customer from outside or orbit decide either to enter the facility or to join the orbit in Bernoulli manner whose entering probability depend on the number of customers in the service facility. In this paper, a stochastic order relation between two bivariate processes(C(t), N(t)) representing the number of customers C(t) in the service facility and one N(t) in the orbit is deduced in terms of corresponding parameters by constructing the equivalent processes on a common probability space. some applications of the results to the stochastic bounds of the multi-server retrial model are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.992-995
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• 2015

In this paper, we developed the computer room environments and infrastructure management systems to operate various networking devices and the infrastructure in the room, stably. The developed systems are composed of the computer room environment management system and the computing infrastructure management system. The computer room environment management system performs the role which the temperature and humidity detection node periodically detects the temperature and humidity and transmits the information to the remote intelligent server. The computing infrastructure management system enables the computer room's manager to check the information and maintenance history of the computing devices with a smart device supporting NFC(Near Field Communication).

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.1-8
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• 2009

Today the use of RFID is extended in medical. circulation market, manufacture, security field, etc. Besides, the book-lending and the attendance management system are on an increasing trend in the use of RFID The developed dormitory management system is composed of a support program, a room management program, a manager program, and a mobile program etc.. In the support program a student(or a manager) can see his(or all member's) entrance and exit history. The room management program decides whether a student can enter the dormitory or not and manages the use of the power after or inquiring a RFID's input tag information into database server. The manager program is able to input and modify a room state and the fixtures information in the room required to operate the room management program, to set up and retrieve a student's entrance and exit information and a room state information. The mobile program enables a manager to check student's identity whether he is in or out, and the manager can know the personal information of being out in detail.

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.11-25
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• 2008

An Adobe Connect Meeting Moodle activity module was developed for the Pai-Chai Moodle virtual learning environment. Professors can create online meeting room directly from their courses by using the Adobe Connect Meeting module. The web services from the server was utilized for the application integration.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.26-28
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• 2015

전산 설비가 운영되는 전산 기계실은 적절한 온 습도 유지가 매우 중요하다. 따라서, 전산 기계실에 대한 온 습도 모니터링 시스템이 중요하게 운영 된다. 하지만 소형 전산 기계실에서는 24 시간 자동 모니터링 시스템이 구축 안되어 있는 경우도 많이 있다. 본 논문에서는 모니터링 시스템이 구축 안된 소형 전산 기계실에서 운영중인 x86 서버들의 온도를 기반으로 전산 기계실의 온도를 모니터링 하는 방법에 대해 제안한다.

• The Journal of Korean Association of Computer Education
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• v.13 no.3
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• pp.55-63
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• 2010

In order to solve the problems of maintenance and security for information-infrastructure, public organizations and some of leading companies adopted Server Based Computing(SBC) infrastructure. The effectiveness and possibility of SBC has become focused with the Cloud-Computing infrastructure, which is a extended concept of SBC, as it is being magnified as a main part among the internet business models for the next generation. The purpose of this study was to analyze its probability in elementary and secondary school and find out its effectiveness. In order to do this, three model schools have been selected from GyeongBuk, ChungNam, ChungBuk province and they were managed by SBC infrastructure. And We conducted analysis of satisfaction for teachers and students, interview with teachers and classroom observation as a effectiveness verification. As the results of the analysis, First, we can find out which part we should consider more when we are to adopt SBC infrastructure. Second, the level of satisfaction for teachers is 3.45 and students is 3.2. Therefore, this study was concluded to contribute to find directions what should be considered when setting the SBC infrastructure in elementary and secondary schools.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.39-46
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• 2023

We present an efficient packet transmission strategy for massively multiplayer online first-person shooter (MMOFPS) games using movement-adaptive packet transmission interval. The player motion in FPS games shows a wide spectrum of movement variability both in speed and orientation, where there is room for reducing the number of packets to be transmitted to the server depending on the predictability of the character's movement. In this work, the degree of variability (nonlinearity) of the player movements is measured at every packet transmission to calculate the next transmission time, which implements the adaptive transmission frequency according to the amount of movement change. Server-side prediction with a few auxiliary heuristics is performed in concert with the incoming packets to ensure reliability for synchronizing the connected clients. The comparison of our method with the previous fixed-interval transmission scheme is presented by demonstrating them using a test game environment.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.177-179
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• 2002

We have developed a scheduling system for heavy ion radiotherapy considering the condition of three treatment rooms and treatment planning for each patient. This system consists of a database (patient information, treatment method and machine schedule), a schedule for radiotherapy and WEB server. All operation of this system, such as data input, to change and to view the schedule, are performed by using a WEB browser. In order to protect personal information for the patients, access privilege to each information are limited by according to the occupational category. This system is connected with a hospital central information management system (AMIDAS) and an irradiation-managing computer for the heavy ion radiotherapy. A basic information for the patient is got from AMIDAS and the daily schedule sends to the treatment control computer at each treatment room through the irradiation-managing computer every morning. The daily, weekly, monthly schedules in the treatment room and the treatment condition of each patient are shared on the WEB browser with the all participants of the heavy ion therapy. This system could be useful to save a time to generate a treatment schedule and to inform us the most up-to-date treatment schedule and the related information at the same time.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.58-66
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• 2008

The KSTAR Current Lead System(CLS) with network based real-time distributed control system is implemented using an EPICS as a middle-ware software. The current lead system transfers current from magnet power supplies to superconducting magnet system and simultaneously supply the coolant to maintain superconducting state. To control the CLS at main control room an EPICS IOC server is installed in local control area. Using this server, it is able to be controlled and monitored the system in main control room through operator interface(OPI) which uses "caget" to read status and "caput" to write command with a unique name called PV. The EPICS IOC is developed using "ether-ip" driver to communicate with PLC. Also we achieved satisfactory results in operation and stability aspects from a long period commissioning test.

• Journal of Drive and Control
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• v.10 no.2
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• pp.7-12
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• 2013

In this study, a wire/wireless communication system transmitting the operation data of engine from the ER (Engine Room) to the engine controller of ECR(Engine Control Room) has been developed through the communication of ISM(Industrial Science Medical) Band for the test operation environment improvement of medium speed engine. This wire/wireless communication system is composed of the RTU (Remote Terminal Unit) gathering and transmitting engine data as well as the MCU (Master Control Unit) receiving engine status information from the RTU to be sent to the engine controller (PLC). Through this study, a trial product of RTU and MCU has been manufactured. A test bench that has made temperature, pressure and pick-up sensor into a module for the local test of prototype was produced a test bench. In addition, at the same time save the data to a Web server and the smart phone real-time monitoring system has been developed using Wi-Fi communications. The ultimate objective of this study is to develop a wireless smart phone monitoring system of engine for the operator of engine to be able to monitor and control engine status even from the outside of engine room and control room based on this study.