• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.177-183
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• 2009

This paper deals with the topical problems of the Life Cycle Costs in connection with the rolling stocks. the LCC philosophy has already entered the third decade. this philosophy contributed towards the new relationship's comprehension between railway vehicle producers' and railway vehicle users' sphere. this leads together to the technical-economical solution convenient for the both sides. In the point of manufacturer, It is said that low operational costs could be reached using a well-designed and structured maintenance program. this is due to the proper technical analysis of critical components that leads to low costs of maintenance and a superior reliability without increasing the capital investment. but, This paper presents both topical experiences with the LCC models for the railways vehicles and also procedures during Life Cycle Costs calculations. In conclusion I want to introduce how to calculate LCC & what kinds of softwares are used based on VVVF EMU vehicle

• 한국군사과학기술학회지
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• 제9권2호
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• pp.51-59
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• 2006

The purpose of this paper is to present reliability analysis procedures for repairable systems and apply the procedures for assessing the reliabilities of two subsystems of a specific group of military equipment based on field failure data. The mean cumulative function, M(t), the average repair rate, ARR(t), and analytic test methods are used to determine whether a failure process follows a renewal or non-renewal process. For subsystem A, the failure process turns out to follow a homogeneous Poisson process, and subsequently, its mean time between failures, availability, and the necessary number of spares are estimated. For subsystem B, the corresponding M(t) plot shows an increasing trend, indicating that its failure process follows a non-renewal process. Therefore, its M(t) is modeled as a power function of t, and a preventive maintenance policy is proposed based on the annual mean repair cost.

• 한국조리학회지
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• 제23권3호
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• pp.196-206
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• 2017

This study intended to examine the Korean restaurant customer's recognition about GIAP and to measure the reliability for them, and to figure out their effects on the customer's satisfaction and revisit intentions. Accordingly, research model had been set up and also hypotheses was made up according to pre-studies and pre-investigation results. Factor analysis and reliability analysis were concluded as valid results by the Cronbach's Alph for GIAP, customer satisfaction and revisit intention each other. Firstly, the effect of GIAP on the customer satisfaction was showed positive significance about four factors - perceived quality, reliability, authenticity and security on the customer satisfaction by the multiple regression analysis. Secondly, The effect of GIAP on the customer's revisit intention was showed positive significance about four factors - perceived quality, reliability, authenticity and security on the customer's revisit intention by the multiple regression analysis. Thirdly, the effect of the customer satisfaction on the customer's revisit intention was showed positive significance by the simple regression analysis. This study focused on medium level-cost Korean-pop restaurant so as to investigate general popular's recognition about the GIAP and intended to figure out their revisit intention. Therefore, the results are useful for increasing the food-service strategy system. Informations about the GIAP in restaurants can be credible to the restaurant customers.

• 마이크로전자및패키징학회지
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• 제20권4호
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• pp.53-58
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• 2013

An innovative packaging solution, Flip Chip with Copper (Cu) Column bond on lead (BOL) Enhanced Process (fcCuBE$^{(R)}$) delivers a cost effective, high performance packaging solution over typical bond on capture pad (BOC) technology. These advantages include improved routing efficiency on the substrate top layer thus allowing conversion functionality; furthermore, package cost is lowered by means of reduced substrate layer count and removal of solder on pad (SOP). On the other hand, as electronic packaging technology develops to meet the miniaturization trend from consumer demand, reliability testing will become an important issue in advanced technology area. In particular, electromigration (EM) of flip chip bumps is an increasing reliability concern in the manufacturing of integrated circuit (IC) components and electronic systems. This paper presents the results on EM characteristics on BOL and BOC structures under electrical current stressing in order to investigate the comparison between two different typed structures. EM data was collected for over 7000 hours under accelerated conditions (temperatures: $125^{\circ}C$, $135^{\circ}C$, and $150^{\circ}C$ and stress current: 300 mA, 400 mA, and 500 mA). All samples have been tested without any failures, however, we attempted to find morphologies induced by EM effects through cross-sectional analysis and investigated the interfacial reaction characteristics between BOL and BOC structures under current stressing. EM damage was observed at the solder joint of BOC structure but the BOL structure did not show any damage from the effects of EM. The EM data indicates that the fcCuBE$^{(R)}$ BOL Cu column bump provides a significantly better EM reliability.

• Structural Engineering and Mechanics
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• 제78권3호
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• pp.351-368
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• 2021

This paper, by applying a reliability-based framework, develops seismic vulnerability macrozonation maps for Tehran, the capital and one of the most earthquake-vulnerable city of Iran. Seismic performance assessment of 3-, 4- and 5-story steel moment resisting frames (SMRFs), designed according to ASCE/SEI 41-17 and Iranian Code of Practice for Seismic Resistant Design of Buildings (2800 Standard), is investigated in terms of overall maximum inter-story drift ratio (MIDR) and unit repair cost ratio which is hereafter known as "damage ratio". To this end, Tehran city is first meshed into a network of 66 points to numerically locate low- to mid-rise SMRFs. Active faults around Tehran are next modeled explicitly. Two different combination of faults, based on available seismological data, are then developed to explore the impact of choosing a proper seismic scenario. In addition, soil effect is exclusively addressed. After building analytical models, reliability methods in combination with structure-specific probabilistic models are applied to predict demand and damage ratio of structures in a cost-effective paradigm. Due to capability of proposed methodology incorporating both aleatory and epistemic uncertainties explicitly, this framework which is centered on the regional demand and damage ratio estimation via structure-specific characteristics can efficiently pave the way for decision makers to find the most vulnerable area in a regional scale. This technical basis can also be adapted to any other structures which the demand and/or damage ratio prediction models are developed.

• Nuclear Engineering and Technology
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• 제23권1호
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• pp.20-29
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• 1991

본 연구에서는 2030년까지의 전력수요, 전력생산중 원자력발전의 비중, 기존 원전표준화 계획, 국내제작 능력을 반영하여 개량형 경수로와 중수로 (CANDU)에 대한 참조 시나리오를 도출하고 각 참조 시나리오와 핵연료주기 전략별 핵연류주기 비용, 원자력 발전 단가, 우라늄 소요량, 인력 소요량을 계산하였다. 참조 시나리오들에 대한 분석을 한 결과 우라늄 자원활용, 원전안전성, 인력활용 측면이 노형 전략수립의 주요 인자로 작용하며 발전단가는 전략별로 큰 차이가 없는 것으로 나타났다.

• 한국통신학회논문지
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• 제38C권12호
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• pp.1170-1178
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• 2013

최근 항공기, 잠수함, 로봇 등 고도의 신뢰성이 요구되는 군사무기체계 분야에 상용 필드버스의 적용이 활발히 이루어지고 있다. 잠수함 전투체계 역시 대표적인 군사용 전자 장비로서 다양한 컴퓨터와 센서 및 액추에이터들이 실시간 네트워크로 연결되어 있다. 잠수함의 작전수행능력 및 생존성과 직결되는 전투체계용 네트워크는 매우 높은 수준의 신뢰성을 만족해야 된다. 그 결과 잠수함 전투체계의 구성장비들을 제어하기 위한 필드버스로써 표준 CAN(Controller Area Network)을 기반으로 채널과 제어기를 이중화한 이중채널 CAN 버스가 주로 이용되고 있다. 본 논문에서는 Petri Net을 이용하여 이중채널 CAN 버스의 신뢰도 분석 모델을 제시한다. 기존연구에서는 네트워크를 통한 정보전송 성능 분석에 주안점이 주어졌으나, 본 논문에서는 CAN의 다양한 물리적 고장 유형을 반영하여 GSPN(Generalized Stochastic Petri Nets) 모델을 제안한다. 제안된 모델을 기반으로 고장율과 고장복구율을 변경하면서 각 고장 유형이 이중채널 CAN 버스의 신뢰도에 미치는 영향을 분석한다.

• 한국항공우주학회지
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• 제38권11호
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• pp.1067-1074
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• 2010

본 연구에서는 이중 쐐기형 초음속 흡입구의 압력회복률에 대한 신뢰성 최적설계를 수행하였다. 주어진 설계영역에서 다양한 설계변수의 불확실성을 고려하여 흡입구의 압력회복률을 확률적으로 모델링하였으며, 목적함수로는 흡입구 항력을 선정하였다. 신뢰성 최적설계에 앞서 전산해석비용을 줄이기 위해 실험계획법과 크리깅 모델을 이용하여 적절한 설계공간을 탐색하였다. 신뢰성 기법의 정확도 검증을 위해 몬테카를로 시뮬레이션을 수행하였으며 이 결과를 신뢰성 기법 결과가 잘 추종함을 확인하였다. 신뢰성 기반 최적설계를 수행한 결과, 설계변수의 불확실성을 고려함으로써 시스템의 신뢰성을 확보하였다. 시스템 설계의 다양한 불확실성을 고려하기 위해서는 신뢰성 기반 최적설계가 유용한 접근방법임을 확인할 수 있었다.

• 정보처리학회논문지A
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• 제16A권4호
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• pp.235-244
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• 2009

대공방어용 임무지향 컴퓨터는 장시간의 대공방어 임무를 성공적으로 완수하기 위하여 고장감내 기능이 필수적으로 요구되며, 고장감내 기법으로는 지상 장비인 임무지향 컴퓨터에 적합한 저비용의 기법이 요구된다. 현재 기본형의 임무지향 컴퓨터에는 저비용의 ASR 고장 감내 기법이 적용되어 있으나, ASR 기법은 TMR 기법을 적용한 컴퓨터에 비해 낮은 임무 신뢰도를 제공한다. 그러므로 본 논문에서는 TMR 기법을 적용한 컴퓨터 보다 적은 수량의 프로세서 보드를 사용하여 우수한 신뢰도를 제공하는 확장형 ASR(EASR) 고장 감내 기법을 제안하였으며, 제안된 EASR 기법 을 적용한 임무지향 컴퓨터의 고장 감내 성능을 입증하였다. EASR 기법의 임무지향 컴퓨터는 고장 감내 성능과 저비용성 측면에서 대공방어 시스템의 컴퓨터에 적합하였다.

• 한국IT서비스학회지
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• 제20권2호
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• pp.13-31
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• 2021

Recently, delivery app services based on the O2O platform are increasing rapidly. Accordingly, various studies on O2O service have been conducted. Most of the studies are on consumer behavior in O2O services, and few studies on platform vendors have been conducted. Therefore, this study empirically analyzed the factors affecting the vender's intention to continuous use in the O2O delivery app platform service. Based on prior researches, we set the quality characteristics and network characteristics of the O2O platform as independent variables. The quality characteristics of the O2O platform consisted of system quality, information quality, and service quality, and the O2O platform network characteristics consisted of network externality and platform reputation. Perceived value and switching cost were set as mediated variables, and vender's intention to continuous use was set as dependent variables. For empirical analysis, we conducted a survey targeting vendors of O2O delivery app platform service, and conducted frequency analysis, factor analysis, reliability analysis, and regression analysis. As a result of the analysis, the quality characteristics of the O2O platform, such as system quality, information quality, service quality, and O2O platform network characteristics, showed that network externality and platform reputation had a positive effect on perceived value. The perceived value was found to have a positive effect on the switching cost and the intention to continuous use, and the switching cost was found to mediate the perceived value and the intention to continuous use. This study can contribute to the establishment of platform operation strategy as an empirical analysis on the factors that influence the intention of O2O platform vendors to use the platform continuously.