• International Journal of Fluid Machinery and Systems
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• v.9 no.3
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• pp.277-286
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• 2016

The development of heavy-duty process pumps, usually based on various design criteria, depends on the pump's application. The most important criteria are Q-H, efficiency and NPSH characteristics. Cavitation due to inlet recirculation is not often one of the design criteria, although many problems in pump operation appear because of inlet recirculation, when the operation range is from 0.5-0.8 $Q_{opt}$. The present paper shows that steady state CFD analysis of inlet recirculation can give quite good results for the design of new hydraulic shapes, which have been developed to expand operating range and to minimize the harmful influence of recirculation at part load. In this paper, the structures of inlet recirculation are presented, as well as detailed shapes of vortices between the blades for various operating regimes, axial velocity distribution at the impeller inlet, the experimental results of NPSH and efficiency characteristics of an existing and newly designed pump.

• Journal of the military operations research society of Korea
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• v.24 no.2
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• pp.30-42
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• 1998

The problems of evaluating Telecommunication Management Network Operation Systems (TMNOS) are Multi-Criteria Decision Making (MCDM) problems. A method for evaluating the TMNOS has not yet been clearly defined. A study of an effective and efficient management methodology for TMNOS, which are heterogeneous and complex, is needed. The components of TMNOS have attributes of dependence between considered criteria or alternatives. This type of dependence impact between criteria or alternatives is a network structure. We suggest a methodology of Analytic Delphi Network Process (ADNP) for evaluating TMONS. The TMNOS problem of Korea Telecom (KT) is suggested as a case study of the ADNP.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1141-1145
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• 2018

Generally, in nuclear plants, distance relay (21R) has adapting to protect and to operate main protective of transmission lines and backup protective of main generator. Operation of 21R was required and based on exactly accurate calculation and criteria. But presently method of 21R setting has applied according to protection devices operation guide of KPX, excepting IEEE and ISA standards, which have a difference review directions, consider parameters and devices, also consideration factors were affected to relay operations by uncertain guides. therefore this paper proposed new protection relay setting method and unvague criteria from IEEE 741 and ANSI/ISA 67.04.01, and reviewed a different results through numerical calculation results for methods and criteria including previous and established 21r setting by IEEE, ANSI/ISA Technical standards.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.8-12
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• 2013

DNV crane criteria are specially designated for the vessel equipped with lifting crane to cover the risk during the crane operation. Based on the DNV crane criteria, the crane performance shall be decided. The weight control has great importance in the management of vessel's design for crane vessel. To evaluate limitation of lightship weight and the effect of design changes sufficiently, the lightship allowable VCG curve was used. The optimization process was carried out for generation of the lightship allowable VCG curve due to the difficulty coming from the characteristic of DNV crane criteria. This paper includes the introduction to the DNV Crane criteria and optimization process for evaluation in aspect of lightship weight and VCG.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.356-362
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• 2008

This study is intended to evaluate the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard in Korea. As a preceding review of this study, the combustibles was categorized and identified their heat release rates. For validate the estimated values, modeling a single underground shop was carried out. And a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out of underground space. From the viewpoint of securing the evacuation time, the results were compared in an attempt to assess the appropriateness of the fire safety criteria.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.363-370
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• 2003

This paper presents the analysis of the load transfer capacity and study of conductor size for variable contingencies in distribution systems. The operation capacity of feeders was changed to improve operation efficiency in KEPCO, considerations for contingencies are still based on the previous capacity. In order to cope with the changes such as operation capacity, it is necessary to study whether the present "contingency support criteria" is reasonable or not, also to confirm the whether the present criteria should be improved or not. We analyze the load transfer capacity and conductor size on a distribution system for contingency levels such as the substation-level, bank-level, feeder-level, and zone-level.one-level.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.478-481
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• 2011

This study is intended to evaluate and optimize the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard, which has been currently applied to the buildings in Korea. Using the heat release per unit weight of the combustibles, a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out at the several different shopping malls. From the viewpoint of securing the evacuation time, the results were compared in an attempt to assess the appropriateness of the fire safety criteria.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.4
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• pp.551-559
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• 2019

Since 2000, many local governments have been trying to introduce trams because of the government's failure to adopt environment-friendly policies and light rail. However, there is no service evaluation system that can maintain and enhance tram users' convenience, safety, and comfort during operation. In addition, the tram characteristics are not reflected in the application of the evaluation system of "management and service evaluation for public transportation operators" which is being implemented to railway operators or bus transportation operators. The purpose of this study is to develop the evaluation criteria of operating service according to tram operation model. First, we reviewed cases related to the evaluation of operating services in roads, buses, railways, and airways. And the evaluation criteria and the evaluation items are presented. This study is expected to help to secure and improve operational service in the operation phase of the tram that will be introduced in the future.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.260-266
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• 2015

Twenty sodium-cooled fast reactors (SFRs) have provided valuable experience in design, licensing, and operation. This paper summarizes the important safety criteria and safety guidelines of intermediate sodium systems, steam generators, decay heat removal systems and associated construction materials and in-service inspection. The safety criteria and guidelines provide a sufficient framework for design and licensing, in particular by new entrants in SFRs.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.36-40
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• 2011

In this report US and Korea civil and military simulator certification system is researched, and a plan for improvement is proposed. Korean simulator certification system should adopt FAA's system and improve upon it. Certification criteria should have a basis on FAA certification criteria and add military operation characteristics selectively. Flight test data, used as comparison criteria in certification, should be acquired in package during aircraft development or overseas acquisition. The establishment of certification system is expected to improve external credibility and improve competitiveness in overseas market.