• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.91-92
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• 2008

The purpose of this paper is to propose a CSMA/CA protocol to reduce the delay time and increase the throughput of the original CSMA/CA protocol. In underwater environments, the efficiency of the protocol is reduced due to the increase of the propagation delay time, which results in increase of the collision possibility causing lowering of the transmission efficiency.

• The Journal of the Acoustical Society of Korea
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• v.9 no.6
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• pp.62-73
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• 1990

한국 포항 연해에서 Range-dependent 환경을 수용할 수 있는 Parabolic Equation에 기초한 수치 해석법을 도입하여 수층의 음속구조, 음원 깊이 및 음원의 주파수 변화가 전달손실에 미치는 영향을 규 명하였다. 수층의 음속 구조에 따라 전달손실 분포는 크게 달라지는데 혼합층 구조와 성층화된 구조 및 수온전선 구조간의 전달손실 변화는 25~40 dB의 큰 차이를 보인다. 성층화된 음속 구조에서는 음원 깊 이 변화에 관계없이 거리에 따라 큰 전달손실을 나타낸다. 그러나 같음 음속구조하에서 주파수를 변화 시켰을 때에는 전달손실 차이가 15~30dB에 이른다. 결국 포항 여해에서 전달손실 분포는 특정 주파수에 대해서 음속구조의 시공간적 변화에 따라 크게 영향을 받는다. 또한 주어진 음속구조하에서 주파수 변 화에 따라서도 전달손실 분포가 크게 변하는데, 이는 Range-dependent 환경하에서도 최적 전달 주파수 가 결정될 수 있는 가능성을 제시한다.

• Journal of Industrial Technology
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• v.37 no.1
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• pp.5-11
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• 2017

The purpose of this research is to propose an efficient loop line operation plan for customer transportation in a new theme park. Based on the expected customer arrivals, customer loading/unloading methods, and scheduled/non-scheduled departure schemes, movement time between stations etc., we have performed indepth analyses and derived the best optimal policy. Our results show that, over all, the operation with separate loading/unloading doors and scheduled departure is preferred to the other options. We then derived the optimal number of trains and cars meeting minimal customer unsatisfaction with low cost for each season.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.257-264
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• 2011

In this study, we performed sensitivity study of the $217Plus^{TM}$ system model to various parameters. Specific attention was put to logistics model and its behavior has been examined in terms of non-component failure causes. We first briefly explained the $217Plus^{TM}$ methodology with system level failure rate evaluation. We then applied experimental designs with several failure causes as factors. We used an orthogonal array with three levels of each parameter. Our results indicate that cannot duplicate, induced, and wear-out causes have dominant effects on the system failures and design, parts, and system management have much less but a little strong effects. The results in this study not only figure out the behavior of the predicted failure rate as functions of failure causes but provide meaningful guidelines for practical applications.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.15-21
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• 2013

World governments and industries have put tremendous efforts for reduction of greenhouse gases. Specifically, IT (information technology) or ICT (information communication technology) is seen to play a pivotal role in green IT since it is deeply penetrated and related to all the industrial and business processes. The objective of this research is to enhance green maturity of a Gangwon province. We first discussed recent trends of green IT approaches/directions and prevailing green readiness indecies. Based on the environmental and industrial characteristics of Gangwon province. a future plan drawn has been examined with regard to a green IT maturity model.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.145-155
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• 2006

High level of reliability in facility operation is specifically required these days. The goal of this study is to secure a methodology for reliability analysis of hydro-power plant so that an appropriate decision for operation and investment can be made. Fault tree analysis of water supply system within hydro-power plant has been performed in this study. We briefly examined the electric power generation facility and water supply system. We then developed fault tree for the water supply system based on failure modes and effects analysis. We conclude this study and provided future research areas.

• Journal of Industrial Technology
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• v.19
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• pp.321-329
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• 1999

An automated manufacturing process mechanism for string musical instruments has been designed in this study. In contrast to other manufacturing products, classical string instruments try to preserve their traditional design shapes even in these days and involve variety of wood working(carpentry) characteristics including highly skilled curved surfaces treatments. Great efforts have been put to develop an integrated and automated system for improved product quality and process control, reduced physical labors, better safety etc. They, however, have been limited to devise jigs and tools with regard to selected processes due to lack of technology and research man-powers. We carefully examined the products and process characteristics, and an automated mechanism which overcome prevailing drawbacks has been derived.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.3-8
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• 2013

Reduction of risk plays a pivotal role in the development of medical instruments. A hyperbaric oxygen chamber, as a medical device, is known to help medical therapy for diversity of diseases through provision of high purity oxygen. The use of hyperbaric oxygen is expected to increase in the future and study to rigorously examine reliability and safety is needed. We have performed risk assessment for a newly developed hyperbaric oxygen chamber in this study. We first briefly discussed the system structure and concept of risk assessment for the study. Based on the hazards identified, we performed preliminary hazard analysis for the chamber.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.9-14
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• 2013

Reliability plays a pivotal role in the development of medical instruments. A hyperbaric oxygen chamber, as a medical/health device, is known to help medical therapy for diversity of diseases through provision of high purity oxygen. The use of hyperbaric oxygen chamber is expected to increase in the future and study to examine reliability and safety is needed. We have performed reliability assessment for a newly developed hyperbaric oxygen chamber in this study. We first briefly discussed the system structure and mechanism. We then performed FMEA (Failure Mode and Effect Analysis) for the chamber. We drew major failure modes affecting the system performance and performed in depth analysis for measuring the expected effects.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.135-144
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• 2006

The significance of hydro-power plant is increasing in its public roles such as flood control and water supply as well as electric power production. Even if high level of reliability in facility operation is required, no specific reliability research has been made. This specifically stems from the lack of technology and research investments. The eventual goal of this study is to secure a methodology for reliability analysis of hydro-power plant so that an appropriate decision for operation and investment can be made. Specific effort was put to develop a reliability model for water supply system within hydro-power plant. For this study, we briefly examined the overview of the hydro-power plant including the electric power generation facility system. We then discussed the facility reliability analysis methodology for hydro-power plant. Based on rigorous examination of the water supply system and components roles, we drew major failure modes for each component and examined their effects.