• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.244-253
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• 1994

Computer networks need a variety of services. Some services such as, video, voice and plantcontrol traffic require a real-time communication with explicit timing constraints. In this pater, we introduce a real-time communication technique which use a reservation technique on dualilnk networks. We introduce an enhanced technique that determines priorities of the message based on time constraints when real-time messages are transmitted. A simulation was conducted to compare and to analyze traditional technique. We used the SLAM II language to simulate this technique. Message loss rate were compared and analyzed as a performance criteria in this simulation.

• Journal of Korean Port Research
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• v.14 no.1
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• pp.27-35
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• 2000

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Navy $\bigcirc$$\bigcirc$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour. Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal has been designed to overlay the Passage I of Pusan Harbour, which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.2-2
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• 1992

최근 여러 분야에서 컴퓨터의 용도가 확산되고 더 높은 computing power에 대한 요구가 증가함에 따라, 컴퓨터의 성능을 향상시키기 위하여 프로세서의 고속화와 함께 시스템 구조의 개선을 위한 많은 연구가 진행되고 있다. 한 시스템내에 여러 개의 CPU들이 존재하는 다중프로세서 시스템(multiprocessor system) 구조를 가진 슈퍼미니급 중형 컴퓨터들은 상호연결망으로서 버스(bus) 방식을 많이 채택하고 있다. 버스 구조는 하드웨어가 간단하여 구현이 용이하지만, 여러 개의 시스템 지원들(프로세서들, 기억장치 모듈들 및 입출력 모듈들)이 버스를 공유하기 때문에 경합으로 인한 지연 시간이 발생하게 된다. 이러한 지연 시간으로 인한 성능 저하를 개선하는 방법으로는 버스 수의 증가와 최적 통제 프로토콜의 설계가 있다. 본 연구에서는 여러 개의 버스를 가진 다중프로세서 시스템에서 4가지 대표적인 버스 중재 프로토콜들에 대해 성능을 분석, 비교하여 최적 프로토콜을 제시하고자 한다. 이러한 대규모 하드웨어에 의하여 구현되는 시스템에서 주요 설계 요소들에 따른 시스템 성능 분석과 비교는 설계 단계에서 필수적인 과정이다. 그러나 하드웨어를 만들어서 분석하는 방법은 시간과 비용이 많이 소요되기 때문에 소프트웨어 시뮬레이션 방법이 널리 사용되고 있다. 본 연구팀에서는 시뮬레이션 전용언어인 SLAM II를 이용하여 다중프로세서 시스템의 시뮬레이터를 개발하고, 버스중재 프로토콜(bus arbitration protocol)을 용이하게 변경할 수 있도록 하여 각각의 성능을 비교하였다. 이 연구에서 비교된 프로토콜들은 고정-우선순위 방식(fixed-priority scheme), FIFO(first-in first-out) 방식, 라운드-로빈 방식(round-robin scheme), 및 회전-우선순위 방식(rotating-priority scheme) 등이다. 실험은 시스템의 주요 요소들인 프로세서와 기억장치 모듈 및 버스의 수들을 변경시킴으로써 다양한 시스템 환경에 대한 분석을 시도하였다. 작업 부하가 되는 기하장치 액세스 요구간 시간가격(inter-memory access request time interval)은 필요에 따라서 고정값 또는 확률 분포함수를 사용하였다. 특히, 실행될 프로그램의 특성에 따라 각 프로토콜의 성능이 다르게 나타날 수 있음을 검증하였으며, 기억장치의 지역성(memory locality)에 대한 프로토콜들의 성능도 비교하였다.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.205-212
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• 2007

Due to the construction of Incheon Grand Bridge, there is driven a necessity for rearranging the function of Inner Port with the development of Outer South Port. In this paper, I'd like to simulate the port operation levels of Lock Gate in Inner Port with estimating the traffic volumes of 2011 and 2015, which will reveal the Demurrage Cost and the Accumulation Cost of Freight in Inner Port. Finally I will evaluate the economic movement effects of the container ship's calling from Inner port to South Port/Outer South Port from 2011 to 2015. The results are as followings ; (1) The average utilization of Lock Gates are reduced by $7\sim8$ percentage point. (2) The mean queueing value are saved by 25 percentage point. (3) The Demurrage Cost and the Accumulation Cost of Freight except Lock Gate charges and the Benefit of Routeing Reduction are saved about 800 million Won annually.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.889-898
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• 2000

In order to support various broadband multimedia servies in the future, we designed a well balanced WDM backbone network. In Korean network traffic environment, six regional centers are selected, link capacities between the regional centers are estimated from the PDI traffic model, and the overall network configuration is designed for the all-optical backbone network. Also, we designed a basic configuration to be able to protect minimum communication capability against link failure. A simulation study is carried out to verify the desired performance of the designed WDM backbone network. Simulation results show that performance of the backbone network is well balanced to support various communication services in Korea in the mid 2000s

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.13-19
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• 2002

In inner harbour of Inchon Port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side 7f 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate Is suspended in every 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The present operational utilization levels of lock gates are 0.2119 in 10KT lock gate, 0.2051 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT) in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate are evaluated to be more rapidly increased up to 24.5% in 2011.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.91-99
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• 1999

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Nary $\infty$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal gas been designed to overlay the Passage I of Pusan Harbour, Which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.57-68
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• 1993

In this paper, we describe a multiprocessor system using the HiPi bus with pended protocol and multiple cache memories, and evalute the performance of the multiprocessor system in terms of processor utilization for various cache coherence protocols. The HiPi bus is delveloped as the shared bus of TICOM II which is a main computer system to establish a nation-wide computing network in ETRI. The HiPi bus has high data transfer rate, but it doesn't allow cache-to-cache transfer. In order to evaluate the effect of cache-to-cache transfer upon the performance of system and to choose a best-performed protocol for HiPi bus, we simulate as follows: First, we analyze the performance of multiprocessor system with HiPi bus in terms of processor utilizatIOn through simulation. Each of cache coherence protocol is described by state transition diagram, and then the probability of each state is calculated by Markov steady state. The calculated probability of each state is used as input parameters of simulation, and modeling and simulation are implemented and performed by using SLAM II graphic symbols and language. Second, we propose the HiPi bus which supports cache-to-cache transfer, and analyze the performance of multiprocessor system with proposed HiPi bus in terms of processor utilization through simulation. Considered cache coherence protocols for the simulation are Write-through, Write-once, Berkely, Synapse, Illinois, Firefly, and Dragon.

• Journal of Navigation and Port Research
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• v.26 no.2
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• pp.177-182
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• 2002

In inner harbour of Incheon port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side of 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate is suspended in energy 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The operational utilization levels of lock gates in 1998 are evaluated 0.2119 in 10KT lock gate, 0.2061 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT0 in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate in 2011 are evaluated to be more rapidly increased up to 24.5% from the levels in 1998.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.337-342
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• 2004

A construction project of Incheon 2nd bridge, which is connected between the Incheon Song-Do New Town and the Incheon International Airport in Young-Jong-Do, have been proposed by the private capital in 1999. But the optimal span width in the bridge main span have not been decided in spite of the three investigations into the feasibility of ship's safe transit in this planned bridge. In this paper, we study the economic analysis on port operational efficiency according to traffic schemes, me-way or two-way of vessels over 10,000G/T, in the bridge main span of this bridge. In this comparative result, total queueing time due to the one-way in the bridge main span is evaluated 20,362 hours in 2011 and 24,544 hours in 2020. Therefore the demurrage cost and the accumulation cost of freight are evaluated 19.7 billion won in 2011, and 23.3 billion won in 2020, then total accumulated costs during 33 years from 2008 until 2040 are evaluated about 768..9 billion won.