• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.473-484
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• 1998

The current interconnection charge regimes is based in fully distributed costing method. Basically this method doesn't give the incument carrier the incentive to promote efficient business operations. In this paper, 1 suggest the adoption of price cap regulation to interconnection charge as incentive schemes and review important considerations in its applications. Additionally I suggest the basic structure of the network costing model for applications of incremental costing method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.165-166
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• 2022

최근 전세계적으로 자율운항선박(Maritime Autonomous Surface Ship, 이하 MASS)의 기술 개발 및 시험 항해가 본격적으로 추진되고 있다. 하지만 MASS의 출현과 별개로 운항 방식, 제어 방식, 관제 방식 등 명확한 지침은 부재한 상태이다. 육상에서는 머신 러닝을 통하여 자율주행차에 대한 다양한 제어 방식을 연구하고 있으며, 이에 따라서 MASS도 제어 또는 통항 방식에 대한 기초 틀을 마련할 필요성이 있다. 하지만 육상과 달리 해상은 기상, 조종성능, 수심, 장애물 등 다양한 변수들이 존재하고 있어 접근 방식이 복잡하여, 머신 러닝을 적용할 때 환경에 대한 요소를 적절하게 설정해야 한다. 따라서 본 연구는 멀티 에이전트 강화학습을 통하여 MASS의 자율적인 통항 방식을 제안하기 위하여 강화학습의 해상교통환경 설정을 위한 요소를 도출하고자 하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.265-268
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• 2005

A series of ignition tests had been conducted for a thrust chamber propelled by Jet A-1 and liquid oxygen with a chamber pressure of 52.5 bara and a thrust of 30 tonf. The chamber ignited by a hypergolic fluid, TEAL, keeps its first constant pressure low at $63\%$ of the design value by $61\%$ of a liquid oxygen mass flow rate and $67\%$ of fuel for 0.25 sec. The operating O/F ratio of the chamber was kept at lower values than that of the design operating condition throughout the whole ignition procedure. Surge of the chamber pressure is below $6\%$ of the design value.

• Proceedings of the KOR-KST Conference
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• 1995.05b
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• pp.202-230
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• 1995

0 동북아지역 경제의 급속한 성장과 남북경제교류 활성화로 수송 부문의 발달이 중요성을 더해 가고 있슴 0 그러나 지금까지 남북철도 연결에 관한 논의는 통일 후의 방안 만 고려되었을 뿐, 통일 전 남북철도 연결을 목표로 하는 구체 적 전략이 부재하였고, 특히 해운과의 경쟁력 비교시 철도시스 템에 대한 이해부족이 지적됨 0 남북 및 대륙연결 최적 철도망을 구축하기 위해서는 다음과 같 은 접근 방안이 효과적임 - 남북 철도연결은 순수 경제적 관점에서, 민간기업이 주체가 되어, 중국철도 등을 중개자로 하여 사업을 추진 - 단계적이며 실용적 접근전략에 따라, 1단계로는 경의선 만을 연결하고, 여객취급을 배제하며, 컨테이너 수송만으로 시작하다가, 광물자원 수송 등 확대 - 초기에는 남북간 수송보다는 한국과 중국 . 러시아 간의 컨테 이너 통과수송 취급에 중점 (북한의 수송수입 강조) - 경의선을 따라 남북 군사분계선 근처에 각측의 경계역을 만들 고, 상대촉 파견관의 검색 및 언수에 따라 열차가 휴전선을 통과하여, 반대펀 경계역에 이르면 기관차 및 승무원을 교체 하며, 화차는 일정 기간 이내 되돌려주는 방식 채택으로 남북 철도 시스댐 차이에 따른 기술적 문제 해소 0 대륙철도의 이용은 동북아 권역내 수송에 중점을 두되, E ESCAP의 활동에 따라 TCR,TSR을 이 용한 유럽 및 중동으로 의 수송도 추진하며, 남북 철도연결 추진과 병행하여 열차페리의 도입에 의한 철도- 해운 복합수송 방식의 활성화를 적극 검토활 것이 필요함

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.107-110
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• 2009

A basic design for a Technical Development Model (TDM) of liquid oxygen lines from the turbopump exit to the oxidizer valves of the combustion chamber and the gas generator was conducted to develop a turbopump-fed liquid rocket engine. The TDM is composed of straight lines, elbows, bellows, a branch, an orifice, flanges and a heat insulator. Materials were determined by consideration of operation conditions, weight constraint and manufacturing procedures. The size and the location of each component were determined by flow analysis of the required flowrate and the pressure loss. Basic designs of the components were conducted by consideration of the operating temperature and the maximum expectation operating pressure. The safety factors were evaluated by structural analysis of design of each component.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.339-342
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• 2007

The power control system of Smart UAV is similar to the propeller pitch governing concept of turboprop aircraft. The pilot inputs the engine power directly and the pitch governor controls the propeller pitch to maintain the propeller RPM. The manual back-up system of PW206C engine is used for the engine power control of Smart UAV. Engine performance estimation program is used to predict the control range of power lever arm(PLA) angle according to the variation of flight altitude and speed. These data provide a guide for the engine control in manual mode operation.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.151-156
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• 2010

Monorail, with the cutting edge technology from EMU system, is small to medium sized transportation solution with bus size capacity, and one of key factors is to minimize size and weight. The Wolmi urban tour monorail, which is a center guide type first ever introduced in the world, is also consists minimizing size and weight of the propulsion system (inverter and motor), which generates considerable amount of heat. This study presents a solution of the structure and method of water cooling system of minimize the size and weight of high efficiency propulsion system, and an effective control method for energy saving.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.10
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• pp.112-119
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• 2003

Design analysis and grow1d test on propellers for 50 m-long airship propulsion were conducted. The design analysis code developed by adopting the vortex-blade-element theory was applied to the design of optimum propeller at the condition of maximum flight speed at sea level. In order to validate the performance of the propeller, ground test of the propeller was performed, and thrust and torque were measured for several different pitch angles at static condition. The power coefficients and thrust coefficients obtained by the test compared well with the analysis results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.126-129
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• 2010

MEMS(micro electro-mechanical systems) inertial switch which is applicable to the ignition Safe-Arm- Unit of propulsion system is devised. The MEMS inertial switch is designed according to the general design procedure for conventional mechanical elements. Unlikely conventional MEMS accelerometer, threshold inertial switching mechanism is adopted which makes a MEMS element an abrupt switching in a certain acceleration level. By comparing the design data and test results of the specimen a small discrepancy in switching acceleration level is found which is presumably due to the nonlinear characteristics of the beam spring and the flexure hinge which are the main parts of the MEMS inertial switch.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.397-400
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• 2008

Traditional propellants which have a hypergolic characteristic have a high performance but also have disadvantages of toxicity and complex handling requirement. In order to replace these propellants, one of the alternatives is hydrogen peroxide which generates high temperature oxygen and water vapor after catalytic reaction. In this paper, autoignition characteristics of kerosene by decomposed hydrogen peroxide were investigated to perform fundamental research for designing a thruster using hydrogen peroxide and kerosene propellants. Contraction ratio, whether flame holder exists or not, and feeding pressure of propellants were selected as variables. From the experiments for different mixture ratio, we confirmed the ignition stability is strongly affected by a feeding pressure of propellants.