• 대한수학회보
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• 제53권4호
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• pp.1213-1235
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• 2016

We prove a uniqueness theorem of nonconstant meromorphic functions sharing three distinct values IM and a fourth value CM with their shifts, and prove a uniqueness theorem of nonconstant entire functions sharing two distinct small functions IM with their shifts, which respectively improve Corollary 3.3(a) and Corollary 2.2(a) from [12], where the meromorphic functions and the entire functions are of hyper order less than 1. An example is provided to show that the above results are the best possible. We also prove two uniqueness theorems of nonconstant meromorphic functions sharing four distinct values with their difference operators.

• Kyungpook Mathematical Journal
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• 제51권2호
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• pp.187-194
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• 2011

Examples of a quartically hyponormal weighted shift which is not 3-hyponormal are discussed in this note. In [7] Exner-Jung-Park proved that if ${\alpha}$(x) : $\sqrt{x},\sqrt{\frac{2}{3}},\sqrt{\frac{3}{4}},\sqrt{\frac{4}{5}},{\cdots}$ with 0 < x ${\leq}\;\frac{53252}{100000}$, then $W_{\alpha(x)}$ is quartically hyponormal but not 4-hyponormal. And, Curto-Lee([5]) improved their result such as that if ${\alpha}(x)$ : $\sqrt{x},\sqrt{\frac{2}{3}},\sqrt{\frac{3}{4}},\sqrt{\frac{4}{5}},{\cdots}$ with 0 < x ${\leq}\;\frac{667}{990}$, then $W_{\alpha(x)}$ is quartically hyponormal but not 3-hyponormal. In this note, we improve slightly Curto-Lee's extremal value by using an algorithm and computer software tool.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 추계학술대회논문집
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• pp.21-30
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• 1993

This paper describes the development of a simulation model of nuclear power plant operators including cognitive aspects by using a network modeling soft ware, Micro-SAINT (System Analysis of Integrated Networks of Tasks) for the analysis of operator performance. Network model description based on Micro-SAINT includes tasks, resources, precedence relations among tasks, flow of information and PSFs (Performance Shaping Factors) on task performance. We have tried to evaluate the performance with several performance measures such as the number of tasks allocated, relative time presure among operators within a shift, for the selected test accident scenarior; small-break LOCA (Loss of Coolant Accident) in a PWR (Pressurized Water Reactor) type nuclear power plant.

• 대한수학회논문집
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• 제21권3호
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• pp.433-449
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• 2006

In this paper, we present some recent developments on hyponormal operator theory and truncated Curto-Fialkow and Embry complex moment problems.

• Journal of the Optical Society of Korea
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• 제3권1호
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• pp.1-9
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• 1999

We have studied the sensitivity of four different phase shift measurement schemes with a Mach-Zehnder interferometer. The input light is considered to be in a coherent state and the detectors are assumed to be ideal with the quantum efficiency of unity. It is shown by direct calculation of the operators corresponding to the measurement schemes that the uncertainty of the phase-shift measurement is limited to the classical one $\frac{1}{\sqrt{m}}$(m is the average number of the photons in the input state) regardless of the phase-shift measurement schemes.

• 한국해양공학회지
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• 제12권2호통권28호
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• pp.97-110
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• 1998

The numerical damping and dispersion error characteristics associated with difference schemes and a panel shift method used for the calculation of steady free surface flows by a panel method are an analysed in this paper. First, 12 finite difference operators used for the double model flow by Letcher are applied to a two dimensional cylinder with the Kelvin free surface condition and the numerical errors with these schemes are compared with those by the panel shift method. Then, 3-D waves due to a submerged source are calculated by the difference schemes, the panel shift method and also by a higher order boundary element method(HOBEM). Finally, the waves and wave resistance for Wigley's hull are calculated with these three schemes. It is shown that the panel shift method is free of numerical damping and dispersion error and performs better than the difference schemes. However, it can be concluded that the HOBEM also free of the numerical damping and dispersion error is the most stable, accurate and efficient.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1846-1851
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• 2007

According to the Railroad Safety Act and section 42 of the Enforcement Ordinance, railway operators should conduct railway safety training regularly(6 or 3 hours per three months). But Overall Railroad Safety Audit conducted 2006 pointed out nonfulfillment of a regulations on railway worker's safety training to each of every 4 railway operators, which proved that the training management had not carried out properly. E-learning is used in various fields with development of Internet and IT technologies. It might be a good alternative tool for railway workers who is in shift working of the company 24 hours a day. Because it is difficult to collect those employees for training, e-learning could overcome obstacles of time and distance. In order to find out suitable e-learning model to railway sector, e-learning system for railway safety training has been researched through investigating e-learning technology and present railway safety training condition.

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.488-494
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• 2008

This paper proposes an effective approach based on binary coding Particle Swarm Optimization (PSO) to identify the switching operation plan for feeder reconfiguration. The proposed method considers the advantages and disadvantages of existing particle swarm optimization method and redefined the operators of PSO algorithm to fit the application field of distribution systems. Shift operator is proposed to construct the binary coding particle swarm optimization for feeder reconfiguration. A typical distribution system of Taiwan Power Company is used in this paper to demonstrate the effectiveness of the proposed method. The test results show that the proposed method can apply to feeder reconfiguration problems more effectively and stably than existing method.

• 한국철도학회논문집
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• 제12권5호
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• pp.751-760
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• 2009

본 연구는 화물수송을 둘러싼 사회적 경제적 환경변화 속에서 철도물류의 활성화가 시대적 과제가 되고 있는 시점에서 철도로의 모달시프트가 기대되는 철도컨테이너수송에 주목하여 화주, 복합운송업체, 운영자를 대상으로 설문조사를 실시, 철도의 이용현황, 이용확대를 위한 개선사항, 환경문제에 대한 대응상황을 분석함으로써 철도물류서비스의 생산성 향상을 위한 개선방안, 나아가 국가정책과의 공동보조를 통한 철도화물수송으로의 모달시프트 가능성에 대하여 검토하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1728-1747
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• 2009

본 연구는 화물수송을 둘러싼 사회적 경제적 환경변화 속에서 철도물류의 활성화가 시대적 과제가 되고 있는 시점에서 철도로의 모달시프트가 기대되는 철도컨테이너수송에 주목하여 화주, 복합운송업체, 운영자를 대상으로 설문조사를 실시, 철도의 미용현황, 이용확대를 위한 개선사항, 환경문제에 대한 대응 상황을 분석함으로써 철도물류서비스의 생산성 향상을 위한 개선방안, 나아가 국가정책과의 공동보조를 통한 철도화물수송으로의 모달시프트 가능성에 대하여 검토하였다.