• Title/Summary/Keyword: operation research

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Integrated Risk Management System for Ship Safety

  • Lee, Jong-Kap;Lee, Soon-Sub;Park, Beom-Jin
    • Journal of Ship and Ocean Technology
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    • v.12 no.4
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    • pp.32-39
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    • 2008
  • According to the increase of the requirement for the safety and environmental protection at sea, safety is a core design factor of maritime systems. Safety is defined as a perceived quality that determines to what extent the management, engineering and operation of a system is free of danger to life, property and the environment. There are many possible approaches in dealing with the safety of ships. The risk-based approach is one of the most systematic and reasonable way currently in design, operation and regulatory works for ship safety. This paper proposes a concept of total risk management for ship safety, and introduces a prototype system implemented based on this concept as a framework of design and operation of ships.

Application of Neural Networks to the Bus Separation in a Substation (신경회로망을 이용한 변전소 모선분리 방안 연구)

  • Lee, K.H.;Hwang, S.Y.;Choo, J.B.;Youn, Y.B.;Jeon, D.H.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.757-759
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    • 1996
  • This paper proposes an application of artificial neural networks to the bus-bar separation in a substation for radial network operation. For the effective bus-bar operation, the insecurity index of transmission line load is introduced. For the radial network operation. the constraints of bus-bar switch is formulated in the performance function with the insecurity index. The determination of bus-bar switching is to find the states of 0 or 1 in the circuit breakers. In this paper, it is tested that the bus-bar separation of binary optimization problem can be solved by Hopfield networks with adequate manipulations.

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Evaluation of KOMPSAT-1 Orbit Determination Accuracy

  • Kim, Hae-Dong;Choi, Hae-Jin;Kim, Eun-kyou
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.588-590
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    • 2003
  • For the normal operations, KOMPSAT-1 orbits are determined using GPS navigation solutions data such as position and velocity vectors. Currently, the accuracy of GPS navigation solution data is generally known as on the order of 10~30 m with the removal of S/A. In this paper, an estimate of the current orbit determination accuracy for the KOMPSAT-1 is given. For the evaluation of orbit determination accuracy, the orbit overlap comparison is used since no independent orbits of comparable accuracy are available for comparison. As a result, It is shown that the orbit accuracy is on the order of 5 m RMS with 4 hrs arc overlap for the 30 hr arc.

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Neutral-Point Voltage Balancing Control Scheme for Fault-Tolerant Operation of 3-Level ANPC Inverter (3-레벨 ANPC 인버터의 고장 허용 운전 시 중성점 전압 균형 제어 기법)

  • Lee, Jae-Woon;Kim, Ji-Won;Park, Byoung-Gun;Nho, Eui-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.2
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    • pp.120-126
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    • 2019
  • This study proposes a neutral voltage balance control scheme for stable fault-tolerant operation of an active neutral point clamped (ANPC) inverter using carrier-based pulse width modulation. The proposed scheme maintains the neutral voltage balance by reconfiguring the switching combination and modulating the reference output voltage in order to solve the degradation of the output characteristic in the fault tolerant operation due to the fault of the power semiconductor switch constituting the ANPC inverter. The feasibility of the proposed control scheme is confirmed by HIL experiment using RT-BOX.

Operation of a Single Flux Quantum 4-stage Shift Register Fabricated with High $T_c$ Ramp-edge Junction Technology (고온 초전도 경사형 모서리 접합을 이용한 4단 쉬프트 레지스터의 동작)

  • Kim, J. H.;Park, J. H.;Kim, S. H.;Jung, K. R.;Kang, J. H.;Sung, G. Y.;Hahn, T. S.
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.83-86
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    • 2001
  • We have fabricated a single flux quantum 4-stage shift register with interface-controlled $Y_1$$Ba_2$$Cu_3$$O_{7-x}$(YBCO) Josephson junction. The YBCO Josephson junctions showed RSJ-like current-voltage(I-V) curves at temperatures 45~80K. We tested load and shift operation of shift register with binary data sequences “1000”, “1010”, “1011”, and “1111” at 58K. For all the binary data sequences, the shift register operated successfully. By operating the circuit with proper current pulses, we observed no errors during at least 12 hours operation for all the data sequences.s.

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A case study on the exclusion of FTA application base on the processing operation of the rules of origin (원산지 규정의 가공공정기준에 따른 FTA 적용배제에 관한 사례 연구)

  • Se-Hyun Park
    • Asia-Pacific Journal of Business
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    • v.14 no.4
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    • pp.401-412
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    • 2023
  • Purpose - The purpose of this study is to analyze cases and suggest implications regarding the exclusion of the agreement tax rate according to the processing process standards of the FTA rules of origin. Design/methodology/approach - In this study, cases in which export and import companies were excluded from applying the agreed tax rate due to the application of processing operation standards after the application of the FTA were analyzed, focusing on the Tax Tribunal precedents, and a literature study was conducted. Findings - The results of this study analyzed through cases of appeal and verification of exclusion from application of the agreement are as follows. Research implications or Originality - Research on FTA cases is active, but this study is differentiated in that it focuses on analyzing cases of exclusion from application of negotiated tax rates based on meeting the processing process standards applied to fields such as textiles and chemicals in FTA.

A study on the certification requirements and operation system for the Airship that flies through the stratosphere (고공비행선 인증 및 운항체계에 대한 연구)

  • Choi, H.S.;Shin, D.W.;Lee, J.H.;Choi, J.W.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.9 no.2
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    • pp.77-89
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    • 2001
  • Recently, the development of an airship that flies through the stratosphere was undertaken in Korea by Korea Aerospace Research Institute like other countries. With the consideration of new operation concept, it is on the rise that the current certification requirements and operation system is not sufficient to secure safety and reliability. This study was performed to establish the certification requirements and operation system. The amendment of airworthiness standards was reviewed by each articles, and the new procedures, as a level of national regulations, for operation was proposed. The results gained through this study can be utilized effectively in the development and operation of subjected airship.

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EMS Helicopter Operation and Flight Safety in Korea (한국에서의 응급의료헬기 운영과 운항안전)

  • Choi, Youn-Chul
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.19 no.4
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    • pp.117-122
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    • 2011
  • EMSS is the organic system offering quick and efficient transfer and treatment for those who need an emergency service. For EMS aviation operation is the important transportation for the common benefits. There are several types of aviation operation. Among the different types of the operations, helicopter operation is very common because it is free from any locations. Notwithstanding the benefit, various types of EMS helicopter accidents and incidents are occurred because of its poor operation condition. In South Korea, even though so much effort was put to decrease the accidents rates, there are still many accidents happening by fire helicopters and the forest service helicopters. Therefore, in order to regularize the EMSH operation, measures for the aviation safety have to be prepared. This research is, related to the EMSH, focused on the suggestion of safety measure for the EMSH in Korea based on the accidents analysis in various countries.

The Estimation Analysis Method of the Annual Operation Cost of Korean High-rise Condominiums

  • Ko, Eun Hyung;Choi, Jun Young
    • Architectural research
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    • v.7 no.1
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    • pp.11-18
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    • 2005
  • In today's building industry the emphasis has been geared more towards construction, thus building maintenance and life cycle have been neglected until now. A direct result of this neglect is the rapid aging of building, which leads to more cost-effective decision making methods for the prolongation of building life span. The following study is conducted in the area of Daegu and Seoul in order to develop the estimation analysis method of the annual operation cost of the Korean high-rise condominiums for the cost-effective decision making support through mathematical and statistical analyses including the present value and standardized measurement corrections. Based on the assumption that the life expectancy of the high rise condominium is 50 years, initial cost is ₩421,212/$m^2$, and a total sum of yearly operation cost during life expectancy is ₩2,154,499//$m^2$), yearly accumulated operation cost is shown as below: $AOC=0.7097t^4-38.803t^3+806.95t^2+11045t-496.52$ ($R^2=0.98$) (Here, AOC = Accumulated Operation Cost, t = given years)

Ego-Identity of Women Seeking Double Eyelid Operation (쌍꺼풀성형술을 원하는 여성의 자아주체성)

  • Choi, Young;Lee, Mi-Suk;Lee, Moo-Suk
    • Korean Journal of Psychosomatic Medicine
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    • v.2 no.1
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    • pp.80-87
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    • 1994
  • Objective : Cosmetic surgery, as a psychosocial intervention, is unique in that its foundation rests solely on the individual motivations, internal or external, of the patient We investigated the ego-identity in women who seek double eyelid operation, to understand one aspect of internal motivation for cosmetic surgery. Methods : Subjects of this study were 47 young women, visited to plastic surgery clinics in Kwangju from June 1993 to October 1993, and 58 women who did not want double eyelid operation were chosen as controls. Each subject's ego-identity was scored using Dignan's ego-identity scale. Results : The total and stability subscale's scores of ego-identity of double eyelid operation group were significantly lower than those of control group. Conclusion : More psychosocial research on the ego-identify of patients seeking double eyelid operation is required to understand the psychological motives for requesting surgery.

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