• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.119-124
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• 1993

This paper describes a method of producing maps of an indoor environment with an autonomous mobile robot equipped with sonar array. This method uses the certainty grid suitable for accommodation of inaccurate sensor data and real-time navigation. Each grid contains a certainty vale that indicates the measure of confidence that an obstacle exists within th grid area. The scheduled firing method is used to eliminate the crosstalk between ultrasonic sensors. The effectiveness of the method is verified by a series of experiments.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.173-176
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• 2009

박격포는 근거리 진지전이나 직사화기 곡사화기로는 사격할 수 없는 배사면의 적을 큰 낙각의 탄도를 그리는 포탄으로 공격할 수 있으므로 보병부대에서 효율적으로 운용되고 있다. 육군에서는 정확성, 기동성 및 사거리가 증대된 120미리 박격포의 도입 필요성을 제기하고 있으며, 관련 연구도 꾸준히 진행되고 있다. 본 연구에서는 120미리 박격포탄 중 사거리연장탄에 사용되는 로켓추진제의 조성을 설계하여 시제품을 제조한 후 지상연소시험과 발사시험을 통해 120미리 박격포용 사거리연장탄의 개발 가능성을 알아보았다.

• 한국소음진동공학회논문집
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• 제26권4호
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• pp.436-442
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• 2016

This paper presents the torsional vibration isolation performance evaluation of a centrifugal pendulum absorbers (CPAs) that has a continuously varying resonance frequencies proportional to engine firing (excitation) order. CPAs are commonly used to suppress torsional vibrations in rotating machinery and internal combustion engines. In this study, they are employed on the current spring type torsional damper inside a torque converter of automotive vehicle. To evaluate the effectiveness of designed resonance tuning order, the torsional vibration transmissibility based on torque measurements with respect to different engine firing orders is experimentally measured with a lower-inertia dynamometer. The torsional vibration transmissibility with respect to different frequencies with engine order of 2 is also evaluated. It has been demonstrated that the significant vibration reduction over operational frequency range of interest can be achieved by attaching simple pendulums. Future research direction includes the study on theoretical analysis, improved design of pendulum etc.

• 전력전자학회논문지
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• 제21권6호
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• pp.473-480
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• 2016

This study proposes a performance improvement for parallel-connected thyristor dual converters using a circulating current with an unbalanced parallel operation compensator. The proposed control method determines a variable reference value for the voltage PI controller according to voltage error at firing angle control applied to a difference current control. This method uses circulating current control to maintain a stable voltage and excellent current response during parallel operation. The effectiveness of the proposed control is verified with a simulation and an experiment based on the comparison of the performance of the proposed control method with other conventional methods.

• 대한치과기공학회지
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• 제21권1호
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• pp.123-130
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• 1999

I attempted to suggest a better method to separate a refractory cast in order to solve the problems caused by bonding between refractory casts and ceramics in the firing-processing of all ceramic crowns as a part of dental prosthodontics. I emphasize the advantages and effectiveness of easy separation after firing by using the separating materials about the refractory cast dies. 1. We must not usse HF(55%) that is used as the chemical separating methods. 2. We decrease such methods as grinding, blasting, bur, and point 3. We can save time, costs and manual labors by using this methods. 4. This method regulates the expansion and constriction of heat because of the chemical reaction of the separating materials. 5. This method contribute to the breaking down without modification by minimizing the chemical and mechanical damages of the marginal and interior parts.

• 대한환경공학회지
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• 제32권2호
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• pp.185-192
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• 2010

본 연구에서는 방해석을 주성분으로 하는 폐굴껍질을 고온에서 소성하여 생석회로 가공한 후 고농도의 납(전함량 29,000 mg/kg)으로 오염된 군부대내 사격장 토양에 처리하여 안정화 효율을 평가하였다. 소성 효과를 평가하고자 소성 전 폐굴껍질(NOS)과 소성 후 폐굴껍질(COS)을 각각 납 오염토양에 처리하였으며 28일간 습윤 양생한 후 0.1N HCl 추출에 의한 가용성 납 농도 변화를 관찰하였다. 실험결과 전 기간 동안 방해석을 주성분으로 하는 NOS에 비해 생석회가 주성분인 COS의 안정화 효율이 높게 나타났다. 또한 완전 습윤 상태 이상의 수분투여는 안정화 효율에 큰 영향을 미치지 않았으며, -#10 mesh에 비해 -#20 mesh의 입경에서 높은 안정화 효율을 나타내었다. NOS에 의한 안정화 처리 결과는 모든 처리에서 토양환경보전법상 '가'지역의 우려1기준 100 mg/kg (환경부 2009년 기준)을 만족 시키지 못 하였으나 COS 15% 및 20% 첨가 시 무처리구의 8,106 mg/kg에 비해 각각 47 mg/kg(28 days) 및 3 mg/kg(28 days)로 현격하게 저감되어 우려기준 100 mg/kg을 만족시켰다. 소성 굴껍질의 안정화 기작을 조사하고자 주사전자현미경(SEM)을 이용하여 elemental dot maps을 수행한 결과 Pb의 안정화는 Al 및 Si와 높은 상관관계가 있음을 확인할 수 있었다.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.175-184
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• 2013

In counterfire warfare, it is important to detect and attack enemy targets faster than the enemy using sensing and shooting assets. The artillery assets of North Korea are mostly mine artillery and much more than those of South Korea. To cope with sudden fire attacks from North Korea, we need to improve capability of our artillery. In this paper, we discuss issues and problems of our counterfire warfare systems and processes to overcome numerical inferiority and defend against the mine artillery. We develop a simulation model for counterfire warfare and analyze effectiveness of our counterfire weapon systems and operations based on various counterfire warfare scenarios. Finally, we propose methods of tactical operations and acquisition strategies of counterfire weapon systems, including detaction, firing, and protection assets.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.720-723
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• 1997

This paper presents a cooperative control method for multiple robots. This method is based on local sensors. The proposed method integrates all information obtained by local perception through a set of sensors and generates commands without logical conflicts in designing control logic. To control multiple robots effectively, a global control strategy is proposed. These methods are constructed by using AND/OR logic and transition firing sequences in Petri nets. To evaluate these methods, the object-searching task is introduced. This task is to search an object like a box by two robots and consists of two sub-tasks, i.e., a wall tracking task and a robot tracking task. Simulation results for the object-searching task and the wall tracking task are presented to show the effectiveness of the method.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1682-1691
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• 2015

In this paper, a real time implementation of selective harmonic elimination pulse width modulation (SHEPWM) using Real Coded Genetic Algorithm (RGA), Particle Swarm Optimization technique (PSO) and a new technique known as Linearization Method (LM) for Single Phase Matrix Converter (SPMC) is designed and discussed. In the proposed technique, the switching frequency is fixed and the optimum switching angles are obtained using simple mathematical calculations. A MATLAB simulation was carried out, and FFT analysis of the simulated output voltage waveform confirms the effectiveness of the proposed method. An experimental setup was also developed, and the switching angles and firing pulses are generated using Field Programmable Gate Array (FPGA) processor. The proposed method proves that it is much applicable in the industrial applications by virtue of its suitability in real time applications.

• 전기학회논문지
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• 제63권8호
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• pp.1080-1084
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• 2014

This paper addresses a design technique for formation tracking controllers of discrete-time Takagi-Sugeno fuzzy multi-agent systems based on consensus. The interconnection topology among the agents is expressed as a digraph. The design condition is represented in terms of linear matrix inequalities. Numerical example demonstrates the effectiveness of the proposed method.