• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2534-2544
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• 2024

This paper proposes a flooding safety system (FSS) and its operation strategy that can provide long-term safety and effective maintenance for modules of small modular reactor (SMR) and metal containment maintained at dried environment during normal operation. During hypothesized accidents, the FSS re-collects the evaporated steam into the common pool by the condenser installed above the common water pool and provides an emergency coolant for the cavities and auxiliary pools. This study suggested that the condensate re-collection strategy using the FSS can effectively delay the depletion of available water in response to the accidents. Without recollection, the achievable grace periods ranged from 44 to 1507 days for six-module and one-module accidents, respectively. However, with a full re-collection (ratio = 1.0), the time to total depletion of emergency coolant was estimated indefinite. Even with a partial re-collection ratio of 0.3, a grace period of 83.5 days could be ensured for a six-module transient. This study reported the effectiveness of condensate re-collection and the FSS as an innovative safety management strategy and system. Employing a condensate re-collection strategy with a high re-collection ratio can enhance the long-term safety and effective convenience of SMR operations and maintenance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.179-185
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• 2014

A use of Asbestos onboard was banned by the provisions of SOLAS since 1 January 2011. And this provision was also implemented by the Rule for Ship's Facilities in Korea. However, these provisions were only declaration and there were no detailed measures for detect, removal and confirmation. In this study, by reviewing the Ship Recycling Convention, IMO circulars and Asbestos Safe Management Act, the following strategies for each concerned parties were proposed. The administration and class society should establish the provisions for appointment of subject vessel which to be inspected for asbestos, criteria for asbestos management and appointment of handling expert. The shipbuilder and equipment manufacturer should make written confirmation that asbestos was not used in their product. And shipowner and ship manager should establish procedure for onboard control of asbestos in the ship's safe management system.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.2
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• pp.77-81
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• 2013

The international standard AIS, which stands for the safety of ship navigation and vessel traffic management, provides 27 messages to exchange the navigational information of ship. Among 27 messages, message ID 6 and 8 are defined as the binary data format to exchange application specific information and are classified into IFM for international use and RFM for national or regional use. Since international standards are based on English, there have been some needs to exchange data in Hangul text for vessel traffic management to correct the static and dynamic ships' information. In this paper, I analyze international standards to provide a Hangul text messaging service based on RFM and propose a RFM message and a simple protocol to correct information of a ship.

• Journal of the Korean Institute of Navigation
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• v.12 no.2
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• pp.43-55
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• 1988

The amount of cargoes and fishery production have increased continuously during the last decade due to the great growth of the Korean economy. These increasements have made our coastal traffic congested, and the future coastal traffic is also expected to increase considerably. The increased traffic can be a cause of large sea pollution as well a s greater sea casualties us as properties and human lives, which could result in a big national loss. In order to prevent the sea casualties and promote the safety of coastal traffic, the Vessel Traffic Management System (VTMS) along the Korean coastal waterway is inevitably introduced. But, the precise evaluation is necessary required prior to the implementation of VTMS because this system necessitates a huge amount of budgets. This paper aims to propose the model of evaluation process, but the evaluation as to the urgency of establishment is not only very complicated and fuzzy but also affected by the subjectivity of human. Therefore, fuzzy integral is adopted as the mathematical model of evaluation in which decision-maker can intervence by making decision considering the calculated membership-function. Four aspects, namely, the frequency of sea-casualities, the traffic volume, the frequency fuzzy day, and the complexity of waterway are selected as the item of evaluation, and the fuzzy measure are applied to the evaluation of 8 candidated regions such as the adjacent area to the port Inchen, Kunsan, Mokpo, Wando, Yosu, Pusan, Pohang, Donghae. As a result of evaluation, the priority as to the candidated regions is obtained, and the following prior execution regions, namely, the adjacent area to the port Pusan, Yosu, Mokpo & Wando are selected by considering the present situation, but, in the long run, the VTMS should be executed in the whole coast of the nation, through the cost-effectiveness analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.856-859
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• 2013

Ships and marine structures(lighthouses and buoys for AtoN) have AIS(Automatic Identification System) for transmission messages which include navigational and environmental information. VTS Center and surrounding ships receive and apply the information to safety navigation. A main characteristic of AIS messages is open to general people, so many researches are in progress. In this paper, we design an information management system which considers marine vessel traffic and environmental information in korean littoral sea. The system gathers and processes the information, and stores the processed data to multi-stage database. Also the system visualizes the stored data to use analysis and statistics based on ENC.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.484-497
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• 2021

This paper proposes an extended time uncertainty analysis approach in Level 2 human reliability analysis (HRA) considering severe accident management (SAM) strategies. The method is a time-based model that classifies two time distribution functions-time required and time available-to calculate human failure probabilities from delayed action when implementing SAM strategies. The time required function can be obtained by the combination of four time factors: 1) time for diagnosis and decision by the technical support center (TSC) for a given strategy, 2) time for strategy implementation mainly by the local emergency response organization (ERO), 3) time to verify the effectiveness of the strategy and 4) time for portable equipment transport and installation. This function can vary depending on the given scenario and includes a summation of lognormal distributions and a choice regarding shifting the distribution. The time available function can be obtained via thermal-hydraulic code simulation (MAAP 5.03). The proposed approach was applied to assess SAM strategies that use portable equipment and safety depressurization system valves in a total loss of component cooling water event that could cause reactor vessel failure. The results from the proposed method are more realistic (i.e., not conservative) than other existing methods in evaluating SAM strategies involving the use of portable equipment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.241-247
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• 2011

Marine casualties of vessel are said to be in most case caused by human error, but it would be valid for the assumption that the ship is built with high quality and then should be acceptable to the safety standards. It means that the inherent characteristics of a ship should be the first consideration on the safety of ship. Therefore it is basically necessary for navigator to grasp the inherent stability of his ship and ensure that the ship complies with the minimum statutory standards of stability. This study is to realize the stability of the Korean offshore large purseiner varying with loading conditions by the inclining data and some calculations. The author compared the stability of the ship with IMO criteria and domestic rule, and proposed some improvement for the safety of the ship. The results are summarized as follows ; The values of GM of the ship according to the loading condition in navigation satisfy both of the IMO criteria and the domestic rule, but in case of the area under the GZ curves between the heel angles of $30^{\circ}$ and $40^{\circ}$, and the heel angle occuring the maximum righting lever not satisfy the IMO rule at the fishing ground departure and arrival conditions in the haul in net situation. The initial metacentric height of the ship is very large, but the range of stability and the occurring angle of the maximum GZ are very small, so even small inclining can bring about the beam end. The best method of improvement for that is to increase the freeboard of the model among the variables.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.721-730
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• 2021

Maritime air pollutants around port cities have gained a great deal of attention due to their direct impacts on regional air quality. This study aims to determine the geographical properties of sea/land breezes in different areas to discover overall ranges of maritime emission dispersion. The HOTMAC-RAPTAD modeling program was used to simulate regional-scale air dispersion considering non-linear and unsteady states during the general summer period for the target areas of the Yellow Sea (Incheon Port and Pyeongtaek·Dangjin Ports), archipelago region (Mokpo Port), South and East Sea (Busan and Masan Ports) and East Sea with mountainous area (Donghae·Mukho Ports). The resulting dispersion lengths of vessel emissions into the onshore regions around the target ports shed light on portal air quality management, because vessel emissions from the Incheon, Mokpo, Busan, and Donghae·Mukho ports were transported 27-31km (Western Seoul), 21-24km (Southern Muan), 20-26km (Gimhae and Yangsan), and 22-25km (Taebeak Mountains), respectively. Therefore, the results of this study provide useful data for regional air quality management and marine air pollution mitigation to improve the sustainability of port cities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.338-339
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• 2015

VTS Decision Support System can be defined a tool which assists VTS operator for decision-making at operational, planning and management level especially for the safety and efficiency of vessel traffic. This paper presents classification of VTS Decision Support System, detailed definition of alerts, and operational and functional requirements of VTS Decision Support System.

• Journal of Korea Ship Safrty Technology Authority
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• s.27
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• pp.53-62
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• 2009

오늘날의 선박은 디지털 선박(Digital-ship)으로 변화하고 있으며, 일부 유비쿼터스(Ubiquitos) 기술을 기반으로 e-Navigation 및 VTS(Vessel Traffic Service) 등 안전 항해 및 편의를 제공하고 있다. 하지만, 아직까지 선박에 대한 안전시스템이 미비하고, 선박의 주요 설비를 실시간으로 관리하기 위한 안전 관리 시스템의 개발이 매우 필요한 시기라 할 수 있다. 지금까지 선박 연구에 있어서 안전을 극대화시키기 위한 노력은 많았으나 선박의 재질(철판) 및 밀폐환경에 의해 무선 통신(Wireless Communication)을 이용한 시스템 개발은 많이 이루어지고 있지 않은 상태이다. 본 논문은 선박 내의 전파 특성을 분석하여 무선 통신을 하기 위한 최적의 조건을 찾고, 유비쿼터스 기술을 적용한 지그비 네트워크 구성으로 선박 내 엔진관리를 위한 무선 센서 네트워크(Wireless Sensor Network)의 적용 가능성을 검증하였다.