• Journal of Advanced Marine Engineering and Technology
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• 제31권7호
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• pp.872-880
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• 2007

The development of a Marine Engine Room Simulator system for training and research is described. Development objectives of the system are for both student training, research and development work. The system includes a distributed server/client architecture for 1 to 1, or 1 to many client simulation operation through OPC server, complete separation of visual elements from the controlling routines and the ability to work on the mathematical model independent of the controller and visual systems. A graphical user interface for the man-machine interface has been developed and the mathematical model has been updated. Various engine room operational situations can be simulated. The use of marine engine room simulator for training of sea going engineers and its competency for STCW-95 is discussed.

• 정보교육학회논문지
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• 제4권1호
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• pp.12-23
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• 2000

Education using the internet, such as a virtual school and distance education, has been limited to the studies of content and method in learning, It has been less studied to make advantage of internet with regard to school administration, teachers' research, and efficient communication within a school. Therefore, it is suggested to implement groupware which can be used in a school environment. For this purpose, this study attempts to design and implement groupware on that purpose. The main content consists of 7 areas: introduction of the school(including children's room), notice room, working room, room for educational materials, individual information, parents' room, internet journey. The basic tool for a groupware is implemented on Windows NT 4.0 Server and subsequent IIS 2.0. DB management based on SQL Server 6.5 makes it enable to manage various information.

• 사물인터넷융복합논문지
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• 제6권3호
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• pp.7-13
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• 2020

본 논문에서는 IoT를 기반으로 서버 룸의 환경을 실시간으로 모니터링하며 제어하는 시스템을 제안한다. 최근 정보화 사회가 극대화되면서 컴퓨터 시스템이 다운되었을 때 그 피해가 크다. 특히, 서버 룸의 화재와 같은 피해는 데이터의 손실로 이어지고 데이터 복구가 불가능하게 된다. 이와 같은 피해를 줄이기 위해서 IoT 시스템을 활용하여 실시간 모니터링할 수 있는 노드를 제안하였다. 또한, 노드의 정보를 취합하고 모니터링할 수 있는 코디네이터 노드를 제안하였다. 제안하는 시스템이 동작하는지 확인하기 위해 노드 모니터링 및 에어컨디셔너를 제어할 수 있는 소프트웨어를 개발하였다. 실험 결과 제안하는 시스템이 화재를 감지하고 상황에 따라 에어 컨디셔너를 제어하는 것을 확인하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.487-492
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• 2008

The cooling of data centers has emerged as a significant challenge as the density of IT server increases. Server installations, along with the shrinking physical size of servers and storage systems, has resulted in high power density and high heat density. The introduction of high density enclosures into a data center creates the potential for "hot spots" within the room that the cooling system may not be able to address, since traditional designs assume relatively uniform cooling patterns within a data center. The cooling system for data center consists of a CRAC or CRAH unit and the associated air distribution system. It is the configuration of the distribution system that primarily distinguishes the different types of data center cooling systems, this is the main subject of this paper.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.241-246
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• 2006

The paper presents the preparations work and experiences gained from realtime GPS car monitoring during the European Rally Championships organized on 10-12 June 2005 in Poland. The developed system is based on GPS and GSM/GPRS technology. Distribution and teletransmission of data are possible using different GSM operators in Poland, which makes the system fully independent. The system's server collects data from rally cars, processing and send data through VPN connections to the SQL server located in main control room. Data can be collected in real time via Internet or GPRS. Some information on GSM/GPRS range during rally championships are also presented in the paper. The study covered many trials and tests of different software and various configurations of the GPRS modems before finally the system started to work. Information coming from 10 Rally Cars were collected to the SQL Server continuously in one second interval. In real time mode these all data were displayed simultaneously in the rally main control room and in the rally press conference room. Paper describes also adopted emergency procedures and remote reconfiguration of GPS/GPRS boxes inside rally cars made during championships. Some problems and method of practical solutions are presented to avoid active jamming dangerous for a driver and his pilot, having system of communication intercoms jammed by teletransmission of GPRS 900/1800 MHz. In cooperation with rally teams special GPS/GPRS safety boxes were designed and made. Monitoring of all 7 rally stages with GPS receivers and method of calibrations of the maps were presented. GSM signal coverage was also checked in all stages. All data transmitted from rally cars were recorded in the computer. Some of our GPS cars had accidents and dispite them information were continuously sent to server. There is possibility to show in post mission mode the position of chosen cars in our rally application. Some information of best rally cars are presented also in the paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.238-241
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• 2002

With the popularity of utilization of the Internet among people, the amount of data in the network rapidly increased. So that, the fall of response time from WWW server, which is caused by the network traffic and the burden on m server, has become more of an issue. This problem is encouraged the rearch by redundancy of requesting the same pages by many people, even though they browse the same the ones. To reduce these redundancy, WWW cache server is used commonly in order to store m page data and reuse them. However, the technical uses of WWW cache that different from CPU and Disk cache, is known for its difficulty of improving the cache hit rate. Consecuently, it is difficult to choose effective WWW data to be stored from all data flowing through the WWW cache server. On the other hand, there are room for improvement in commonly used cache replacement algorithms by WWW cache server. In our study, we try to realize a WWW cache server that stresses on the improvement of the stresses of response time. To this end, we propose the new cache replacement algorithm by focusing on the utilizable information of network distance from the WWW cache server to WWW server that possessing the page data of the user requesting.

• 설비공학논문집
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• 제25권2호
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• pp.79-84
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• 2013

In this study, a cold aisle containment system was proposed among various strategies to reduce the energy waste by recirculation air from the hot aisle. To verify the effectiveness of the cold aisle containment system, a test bed which is similar to an actually existing server room was set up in the Internet Data Center(IDC) building. Comparative experiments, conventional open type cooling system and cold aisle containment system were carried out under actual conditions. The result revealed that the range of inlet temperature of the server system was $20{\sim}25^{\circ}C$ in an existing cooling system and the range of inlet temperature dropped below $20^{\circ}C$ by the cold aisle containment system. After all, cold aisle containment system was proved to be the solution for energy saving cooling system.

• 한국컴퓨터정보학회논문지
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• 제9권4호
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• pp.127-131
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• 2004

본 논문에서는 소규모 실습실을 대상으로 웹기반의 네트워크 트래픽 모니터링 시스템을 제안한다. 제안된 시스템은 네트워크 관리자로 하여금 네트워클 분석하여 네트워크와 시스템의 운영 및 관리, 확장. 그리고 디자인을 지원할 수 있다. 전체 시스템은 네트워크 정보를 수집하고 분석하며, 네트워크 트래픽의 실시간 분석을 지원하는 분석 서버와 서버로부터 수신된 결과를 분석하여 사용자에게 그래픽적인 데이터로 보여주는 웹기반 사용자 인터페이스인 클라이언트 시스템으로 구성된다. 제안된 시스템은 웹기반 기술인 자바로 구현되었으며 다양한 분석 기능 및 활용방안을 제공함으로써 관리자로 하여금 실습실에 대한 효율적인 관리 활동을 지원할 수 있도록 한다.

• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.469-474
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• 2011

In a M/G/I queue where the server alternates between busy and idle periods, we assume that firstly customers arrive at the system according to a Poisson process and the arrival process and customer service times are mutually independent, secondly the system has infinite waiting room, thirdly the server utilization is less than 1 and the system has reached a steady state. With these assumptions, we analyze waiting times on the systems where some vacation policies are considered.

• 한국전자통신학회논문지
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• 제12권2호
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• pp.385-390
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• 2017

IT기술의 발달로 기업의 각종업무, 공장 자동화시스템, 병원 의료시스템 등 다양한 방면에서 전산화된 시스템을 도입하여 운영하고 있으며 시스템이 정지되었을 경우 모든 업무가 정지될 정도로 전산 시스템의 중요도는 그 어떠한 것보다 중요하다 할 수 있을 것이다. 이러한 상황에서 시스템의 정상 운영을 위해 서버실의 온도, 습도, 화재등과 같은 환경 관리에도 항상 신경을 써야 한다. 이러한 소규모 서버실 운영을 위해서는 담당자가 신경 쓰지 않는 상황에서 24시간 독자적으로 환경 모니터링을 하고 이벤트 발생 시 실시간으로 담당자에게 알려주는 저비용의 시스템이 필요하다고 생각되며 이러한 문제를 해결하기 위해 데몬 프로세스와 아두이노를 기반으로 한 장비의 연동 결과 담당자에게 실시간 환경 데이터를 제공하고 특정 이벤트 발생 시 그 이벤트에 대한 내용을 제공하여 그로인해 발생할 수 있는 문제 등을 미연에 방지 할 수 있을 것으로 기대한다.