• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.569-574
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• 2020

A floating dock is the main facility for launching ships. In the early 2000s, ship-launching technology using floating docks was developed in Korea. Therefore, the opportunity to participate in new construction projects without investment in dry docks has expanded. In this paper, a basic calculation for the safe mooring of a floating dock was performed, and a mooring system was designed based on this. This study was conducted considering the typhoon situation, which is the most serious environmental requirements of Daebul Pier, a site to be installed and operated, for a floating dock. The design load was calculated by wind load, tidal load, and wave-induced load in accordance with the internationally accepted standards. After performing the initial arrangement of the mooring line of the floating dock using the existing mooring facilities of Daebul Pier, the minimum breaking load for each mooring line was calculated for the given load. Based on the calculation, the mooring arrangement was modified to minimize the breaking load, and a final specification of each mooring line was selected.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.78-84
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• 2006

As electric power systems have been moving from a vertically integrated structure to a deregulated environment, calculating reactive power service charges is a new challenging theme for market operators. This paper examines various methods for reactive power management adopted in some deregulated foreign and domestic markets and then proposes a new method to calculate reactive power service charges using a reactive power market. The reactive power market is operated based on bids from the generating sources and is settled on uniform prices by running reactive OPF programs after the day-ahead electricity market. The proposed method takes into account recovering not only the costs of installed capacity but also the lost opportunity costs incurred by reducing active power output to increase reactive power production. A numerical sample study is carried out to illustrate the processes and appropriateness of the proposed method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.3
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• pp.232-242
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• 2005

It has been recognized that solar water heating systems are economically inferior to conventional gas water-heaters and boilers using light oil as fuel in spite of having practical possibilities among other alternative energy facilities in Korea. The solar system, however, should be revaluated due to the sharp rise of oil prices recently. We have calculated the energy amount and cost through a series of research projects for the system by experiment and simulation, which lead to analyzing reliable life cycle costs. For the economic analysis, the gas water-heater and light oil boiler were taken as base cases while the solar systems implemented with these facilities were compared as alternatives. As a result, the solar system using the light oil as an auxiliary fuel surpassed the light oil boiler in economics. And a $50\%$ government subsidy for the initial cost is needed to maintain competitiveness with the gas hot-water heater. With this support, the simple payback period of the system can approach 12.8 years under $20\%$ additional curtailment of expenditure.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.45-53
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• 2014

In this study, we analyzed the next generation ITS (C-ITS) technology trends, focusing on the national and international C-ITS projects. Based on the promotion practices of developed countries, we pointed out the lack of linkages with the existing ITS infrastructure. As a way to overcome this problem, we proposed the three-direction to enable the existing ITS infrastructure corresponding to the C-ITS. First one is developing a technique to improve the performance of the existing ITS infrastructure and automate the performance management (Performance-enhanced ITS). Second, developing active sensors or fusion sensor which along with V2X communication technology implement of an active safety driving support system (Safety-enhanced ITS). Third, we need to develop a technology that generate the new advanced traffic data by integrating the collected data from existing ITS infrastructure and nomadic device (Cloud-ITS). By improving the function of the existing ITS infrastructure for adaptation to the new V2X communication environment, we enhanced the efficiency of maintenance performance and would maximize the benefit of the introduction of C-ITS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4B
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• pp.234-245
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• 2007

There are lots of controversies over the introduction of MVNO(Mobile Virtual Network Operator) policy to Korean mobile telecommunications market. MVNO is a kind of service-based competition in mobile market. This paper attempts to analyze the ripple effect of MVNO regulation and also desirable ways of implementing the policy. Based on Laffont, Rey and Tirole(1998), Armstrong (1998) model, theoretical MVNO model is defined and derived implications of price, quantity in the market. According to the model, the fact that MNOs have one-way access profit leads the static efficiency by lowering its market price. In regarding the most desirable way to enhance social welfare is revealed as 'two MNOs conduct MVNO' other than 'One MNO does' or 'Structurally divided network'.

• Proceedings of the Korea Society for Simulation Conference
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• 1994.10a
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• pp.7-8
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• 1994

최근 들어 원자재, 재공품 또는 완제품을 신속하고 정확하게 공급/배분하기 위해 저장과 인출을 담당하는 Material Handling System을 이용하여 작업자의 개입요소를 줄이며, 제고관리 Computer를 이용하여 입고/출고 명령을 유효적절하게 처리하는 ASRS(Atomated Storage and Retreival System : 자동창고 시스템)가 널리 공급되고 있다. 중앙은행의 현금창고, 병원의 약품창고, 식품/화장품 회사의 배송창고, 군수물자의 군납창고에 이르기까지 물품의 저장 또는 공급의 필용성을 갖는 곳에서는 어디든지 찾아볼 수 있는 ASRS는 가깝게는 관공소나 대형빌딩의 주차장에도 이의 개념이 도입되어 사용됨을 볼 수 있다. 최근의 인금인상, 구인난등의 이유로 ASRS설치는 계속 증가할 추세에 있으나 자동 창고 시스템을 설치하기 위해서는 막대한 초기 투자가 필요하며 시스템의 설계 및 설치후 운영에 대한 연구가 반드시 필요하다. ASRS의 운영 Rule 검증, 수행능력 분석등의 목적을 갖는 연구에는 여러 접근방법이 있을 수 있으나 구성 설비와 운영 Rule의 복잡한 관계로 컴퓨터 시뮬레이션의 거의 유일한 문제해결 방법이다. ASRS의 Modeling에 관한 기존의 연구로는 수리모델 수립. 이산사건 시스템의 관점에서 event-graphy, petri-net을 이용한 modeling이 있으며 ASRS에 대한 전용 Simulator 개발등이 진행되었다. 본 연구의 대상 시스템은 2개의 Rack과 하나의 Stacker Crane 으로 구성된 Aisle과 입출고의 물류를 처리하는 순환 RGVS(Rail Guided Vehicle System), 입/출고장을 구성하는 Conveyor Net등으로 이루어진 제조-물류시스템의 일반적인 ASRS이다. 또 이 ASRS의 입/출고 방식은 전수 입/출고만을 포함하며 Blocking 방지를 위한 Capaicty 예약, 다중설비 선택등의 문제등을 고려하고 있다. 본 연구의 접근방법으로는 ASRS의 개념적인 Reference Model을 수립하고 이 Reference Model에 대한 Formal Model로 DEVS(Discrete Event System Specification)을 이용하여 시스템을 Modeling하였다. 이의 Computer Simulation을 위하여 DEVS형식론 환경에서의 Simulation Language인 DEVSim ++ⓒ를 이용하여 시스템을 구현하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.176-183
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• 2009

Distributed generation(DG) of combined cooling, heat, and power(CCHP)has been gaining momentum in recent year as efficient, secure alternative for meeting increasing energy demands. This paper presents the energy performance of microturbine CCHP system equipped with an absorption chiller by modelling it in hospital building. The orders of study were as following. 1)The list and schedule of energy consumption equipment in hospital were examined such as heating and cooling machine, light etc. 2) Annual report of energy usage and monitoring data were examined as heating, cooling, DHW, lighting, etc. 3) The weather data in 2007 was used for simulation and was arranged by meteorological office data in Daejeon. 4) Reference simulation model was built by comparison of real energy consumption and simulation result by TRNSYS and ESP-r. The energy consumption pattern of building were analyzed by simulation model and energy reduction rate were calculated over the cogeneration. As a result of this study, power generation efficiency of turbine was about 30[%] after installing micro gas turbine and lighting energy as well as total electricity consumption can be reduced by 40[%]. If electricity energy and waste heat in turbine are used, 56[%] of heating energy and 67[%] of cooling energy can be reduced respectively, and total system efficiency can be increased up to 70[%].

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.414-416
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• 2003

As environmental conditions for memory products are increasingly high speed/high density, adopting diverse system configuration, it's more and more difficult for current component tester to adopt the actual condition of field application. If system test screening is realized in component level, test coverage failure can be made more secured in the initial stage, evaluation cost can be reduced and the effectiveness of investment for the facility can be maximized. Based on the above background, component automatic system tester was developed and showed off satisfactory results per each memory device family. In this paper, component quality stabilization strategy and cost saving for tester investment through future Quality monitoring and application to mass production will be presented.

• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.13-25
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• 1996

This study was conducted to analyze the technological levels of the domestic industries manufacturing the machinery and equipment for livestock production facilities and to lay out a scheme for upgrading the technical improvement. The results of this study are as follows : 1 . According to the study results, the technological levels of the domestic industries for livestock production facilities lag far behind those of the advanced countries in this field. 2. It was found that the ratio engaged in the areas of R&D was 10.7% and lower than that engaged in the other areas and the ratio of junior college graduated engineers engaged in the areas of research and design was 44.4%. Therefore, the amounts of investment for the areas of R&D and design should be increased. 3. In the design area, it was found from the study that the most weakness technologies which should be developed in near future were the universal harvester and the mechanical designing. Therefore, the multipurpose universal harvester suitable to the domestic farmland conditions should be developed and strength, hardness, and durability of materials in the mechanical designing should be improved.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.479-485
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• 2023

Although fire incidents occur frequently in factory buildings, the focus has primarily been on property damage rather than human casualties. In this study, we conducted an analysis of RSET(Required Safe Egress Time) variation by examining the relocation of workbenchs using evacuation simulations. The results demonstrated that a simple change in workbench placement led to different RSET and variations in the feasibility of evacuation. Specifically, arranging workbenchs in a vertical configuration reduced travel time for workers and minimized total evacuation time. The hybrid layout of "vertical-horizontal" exhibited the shortest RSET, while the "horizontal-vertical" configuration resulted in the longest RSET. These research findings are significant as they provide practical alternatives to decrease RSET in small-scale factories where additional investments beyond essential safety equipment may pose challenges due to budget constraints. However, it is important to note that this study solely focused on comparing RSET while controlling for all other factors, without considering real-life fire simulations. Therefore, further research is necessary to integrate fire simulations and conduct comprehensive assessments of evacuation safety.