• 품질경영학회지
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• 제40권2호
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• pp.145-155
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• 2012

The purpose of this study is to suggest the direction of improving service quality in the defense logistics support. For this, this study compares and analyzes the perceived service quality between customer(using unit) and defense logistics support unit by using SERVPERF model. Supply, military meals, and maintenance are carrying out the mission as core function of defense logistics support and also encounter with customer. In this empirical analysis, the service quality is composed of four factors, and there are significant difference in perception level of service quality between them. Also, the relationship between factors of service quality and revisit intention shows significant difference statistically, and the customer orientation and responsiveness are key affecting factors on revisit intention.

• 전기학회논문지P
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• 제51권4호
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• pp.186-192
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• 2002

In this paper, interleaved boost power factor corrector(IBPFC) is applied as a pre-regulator in switch mode power supply. IBPFC can reduce input current ripple and effectively increase the switching frequency without increasing the switching losses, because input current is divided each 50% by two switching devices. IBPFC can be classified as three cases by duty ratio condition in continuous current mode and be carried out state space average modeling. According to the modeling, steady and transient state analysis is performed by steady elements and perturbation element. Control transfer function is derived for design of control system.

• Journal of Power Electronics
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• 제14권3호
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• pp.572-579
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• 2014

As a non-linear time variant system, the four-quadrant line converter of an electric multiple unit (EMU) was expressed by linear time periodic functions near an operating point and modeled by a steady-state harmonic domain matrix. The components were then combined according to the circuit connection and relations of the feedback control loops to form a complete converter model. The proposed modeling method allows the study of the amplitude of harmonic impedances to explore harmonic coupling. Moreover, the proposed method helps provide a better design for the converter controllers, as well as solves the problem in coordination operation between the EMUs and the AC supply. On-site data from an actual $CRH_2$ high-speed train were used to validate the modeling principles presented in the paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.418-420
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• 2007

When the magnetic levitation system(MAGLEV) initially rise, The MAGLEV has a weak point that is very large variation of the electric current. In this paper, The author applied the multi-loop-control to stably control the magnetic levitation system(MAGLEV). The gains of the control algorithm were selected based on pole locations formulated from a prototype Bessel transfer function model. The design incorporate tradeoffs in DC-to-DC converter hard-ware para-meters and pole locations. In order to confirm the superiority of the proposed pole selection and controller, MATLAB simulation and experiment results are presented.

• 물과 미래
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• 제18권4호
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• pp.347-359
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• 1985

본 연구는 단일다목적 저수지의 운영정책을 수립함에 있어서, DP를 적용하여 댐의 여러 물리적 제약조건하에서 댐 하류의 용수수요를 최대로 충족시킬 수 있는 월별 저수지 최대 운영정책을 수립하는 알고리즘을 개발하는데 주안점을 두었다. 분석대상인 안동댐의 과거 월평균 유입량으로부터 장래 월유입량을 모의발생시키고, 그 모의 발생된 자료 중에서 ddlqfid 계열 A, B, C를 선정하여, 각 계열별로 낙동강 본류의 용수수요 중에서 안동댐이 30%∼100%까지 충족시킬 수 있도록 8개의 대안을 설정하였다. 그리고 DP 모델을 적용시켜 물 수요량과 운영곡선에 근거한 시스템 운영목적함수를 가장 잘 수행하는 대안을 최적 운영 정책으로 결정하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1579-1602
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• 2020

In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system's multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.

• 전기학회논문지
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• 제64권6호
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• pp.885-890
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• 2015

LLC resonant converter has been widely used because of its high efficiency and high energy density. In this paper, we designed a LLC resonant converter as the main power supply of the Nd:YAG pulse laser. First harmonic approximation (FHA) is used to model the LLC resonant converter. FHA equivalent circuit model and the transfer function of the LLC resonant converter is proposed. Soft start technology is also used to suppress the surge current. The laser output simulation test result is identical with the practical test, the laser energy of every pulse can reach up to 2.5J, and the pulse per second (PPS) can be adjusted from 6 to 18. The power system is verified stable and reliable by both of the simulation and experiment results.

• 한국국방경영분석학회지
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• 제35권3호
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• pp.1-15
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• 2009

현재 공군은 중앙창에서 국내 조달물자와 해외 도입물자를 공급받아 보관하고 전국 각 기지로 수송하여 기지별로 필요한 물자를 공급하고 있다. 이러한 물자를 중앙물자라고 부르며 항공, 철도, 육로 등 다양한 방편을 이용하여 수송한다. 이 중 항공이 차지하는 비중은 전체 물자의 10% 정도이며, 그 물량이 날로 증가하고 있다. 이렇듯 군에서 항공수송의 비중이 점점 커져가고 있지만, 항공수송을 활성화시키기 위한 수요예측이나 노선설계와 같은 연구는 매우 미흡한 실정이다. 본 연구는 회귀분석을 통하여 항공수송에 미치는 주요 요인과 영향력을 검증하였고 산출된 회귀모형식은 군 항공화물수요 예측에 있어 유용한 자료가 될 것이다.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.113-122
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• 2021

This study aims to investigate the effects of fiscal policy instruments on economic growth in Jordan using annual data from 1970 to 2019, by applying the VAR model (Vector Auto regression) and the Vector Error Correction Model (VECM). The study also examines the dynamic relationship among economic variables over time using the Granger casualty test, Impulse Response Function, and Variance Decomposition. The results show that not only the public expenditures have a positive effect on economic growth in Jordan, but also the tax revenues positively affect the economic growth in the short-run, and this is because of using the tax revenues to finance the government activities in Jordan. This effect becomes negative in the long run, and this is explained because the tax seems a source of distortions in the economy, The extreme taxes may cause huge distortions in the economy, and these distortions destroys the purchasing power, the aggregate demand, and supply. More governmental dependence on tax revenues is the main source of tax evasion and less efficiency. The effect of taxation will curb any prosperity in the economy. Therefore, the government should estimate the fair tax rates to generate sufficient revenues to finance the public expenditure required to enhance economic prosperity.

• 대한공간정보학회지
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• 제13권1호
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• pp.55-61
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• 2005

정사영상 생성, 도시 공간의 모형차 등 도면화의 다양한 응용분야에 적용을 위해서는 위성영상으로부터 수치고도모형을 생성하는 것은 중요하며, SPOT-5, IKONOS, QUICKBIRD, ORBVIEW 등의 고해상도 위성영상은 효율적이고 경제적으로 수치고도모형을 생성할 수 있는 정보를 제공하고 있다. 그러나, 이들 고해상도 위성영상으로부터 수치고도모형을 생성하기 위해서는 센서모형화, 에피폴라 영상 생성 그리고 영상정합에 대한 사전지식이 필요하다. 이들 중 에피폴라 영상생성은 중요한 인자이며 이에 대한 연구는 아직 미흡한 실정이다. 뿐만 아니라, IKONOS 위성영상으로부터 수치고도모형을 생성하는 연구는 다항식비례모형에 기반한 연구가 주로 이루어졌다. 이에 본 연구에서는 센서 독립적이면서 적은 수의 기준점만으로 센서모형화와 에피폴라 영상생성이 가능한 평행투영모형을 이용하여 수치고도모형을 생성하는 일련의 처리과정을 새롭게 제안하였다. 제안된 방법론은 IKONOS 위성영상을 이용하여 적용하고 평가하였다.