• Journal of Welding and Joining
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• 제29권1호
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• pp.59-64
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• 2011

Al6082-T6 is widely used because of its corrosion resistance and excellent strength. HAZ softening occurs in MIG welding process for this aluminium alloys because this aluminium alloy is heated to higher temperature than its aging temperature during welding. Therefore, low heat input and minimum standard deviation of heat input are required for narrow HAZ width and, for higher strength of welds. In this study, Al6082-T6 was used to examine for HAZ softening with various heat input in aluminium MIG welding. For weldments, micro hardness was measured and tensile test was carried out. Minimum hardness was increased at high speed welding such as 80cm/min and 120cm/min in welding speed comparing with 40cm/min. Also, in case of high speed welding such as 80cm/min and 120cm/min, tensile strength of weldments was increased about 10% comparing with low speed welding(40cm/min).

• 한국정밀공학회지
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• 제22권7호
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• pp.122-129
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• 2005

Shoe with leather upper such as safety and golf shoe requires a roughing process where the upper is roughed fur helping outsole to be cemented well. It is an important and basic process for production of leather shoe but is not automated yet. Thus, there are problems that the defect rate is high and the quality of roughed surface is not uniform. In order to solve such problems, the interest in automation of roughing process is being increased and this paper introduces CAM system for 5-axis automatic roughing machine as one part of automation of roughing process. The CAM system developed interpolates a B-spline curve using points measured from the Roughing Path Measurement System. The B-spline curve is used to generate the tool path and orientation data fer a roughing tool which has not only stiffness but also flexibility to rough the inclined surface efficiently. For productivity, the upper of shoe is machined by side of the roughing tool and tool offset is applied to the roughing tool for machining of inclined surface. The generated NC code was applied to 5-axis polishing machine for the test. The upper of shoe was roughed well along the roughing path data from CAM and the roughed surface was proper fur cementing of the outsole.

• 한국생산제조학회지
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• 제24권6호
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• pp.718-723
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• 2015

This paper describes the conceptual platform design of a dual-capable robot for both driving on the ground and flying in the air. The dual-capable robot can move over all types of terrain for both ground and aerial reconnaissance. The main design problem of the robot is how to make a wheel for both driving and flying. The proposed key design concept is a hubless driving wheel that contains a propeller inside for flying in the air. The primary design parameters and initial specifications were confirmed through an examination of the conceptual design, and functional tests were then conducted using a real prototype robot for driving and flying modes. The test results show the feasibility of the proposed design concept.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• 전기학회논문지
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• 제65권5호
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• pp.811-818
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• 2016

This paper suggests a structure of power control system in floating wave-offshore wind hybrid power generation system. We have developed an unified SCADA(Supervisory Control and Data Acquisition) system which can be used to monitor and control PCS(Power Conversion System) based on IEC61850. The SCADA system is essential to perform the algorithm like proportional distribution and data acquisition, monitoring, active power, reactive power control in hybrid power generation system. IEC61850 is an international standard for electrical substation automation systems. It was made to compensate the limitations of the legacy industrial protocols such as Modbus. In order to test the proposed SCADA system and algorithm, we have developed the wind-wave simulator based Modbus. We have designed a protocol conversion device based on real-time Linux for the communication between Modbus and IEC61850. In this study, SCADA system consists of four 3MW class wind turbines and twenty-four 100kW class wave force generator.

• Journal of Power Electronics
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• 제19권5호
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• pp.1326-1335
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• 2019

Common mode (CM) chokes are a crucial part in EMI filters for mitigating the electromagnetic interference (EMI) of switched-mode power supplies (SMPS) and for meeting electromagnetic compatibility standards. However, the parasitic capacitances of a CM choke deteriorate its high frequency filtering performance, which results in increases in the design cycle and cost of EMI filters. Therefore, this paper introduces a negative capacitance generated by a negative impedance converter (NIC) to cancel the influence of equivalent parallel capacitance (EPC). In this paper, based on a CM choke equivalent circuit, the EPCs of CM choke windings are accurately calculated by measuring their impedance. The negative capacitance is designed quantitatively and the EPC cancellation mechanisms are analyzed. The impedance of the CM choke in parallel with negative capacitances is tested and compared with the original CM choke using an impedance analyzer. Moreover, a CL type CM filter is added to a fabricated NIC prototype, and the insertion loss of the prototype is measured to verify the cancellation effect. The prototype is applied to a power converter to test the CM conducted noise. Both small signal and EMI measurement results show that the proposed technique can effectively cancel the EPCs and improve the CM filter's high frequency filtering performance.

• 한국산업융합학회 논문집
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• 제22권3호
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• pp.281-292
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• 2019

This paper proposed a new technology to control a path forging parts in limited narrow space of manufacturing process automation for smart factory. In the motion control, we adapted the obstacle avoidance technology based on ultrasonic sensors. The new motion control performance test for a mobile robot is experimented in narrow space environments. The travelling path control is performed by a fuzzy control logic. which plays a role for selecting an appropriate behavior in accordance with the situation in the vicinity of the mobile robot. Ultrasonic sensors installed at the front face of the mobile robot are used. In order to update the current position and heading angle of the mobile robot, a new approch is adapted. The reliability is illustrated by simulation and experiments.

• 한국게임학회 논문지
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• 제20권6호
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• pp.63-74
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• 2020

최근, 사람 대신 인공지능 에이전트를 이용하여 게임 테스트를 자동화하는 연구가 관심을 모으고 있다. 본 논문은 게임 밸런싱 자동화를 위한 선행 연구로써 사람과 인공지능으로부터 플레이 데이터를 수집하고 이들의 유사도를 분석하고자 한다. 이때, 사람과 유사한 플레이를 할 수 있는 인공지능의 생성을 위해 학습 단계에서 제약사항을 추가하였다. 플레이 데이터는 14명의 사람과 60개의 인공지능을 대상으로 플리피버드 게임을 각각 10회 실시하여 획득하였다. 수집한 데이터는 코사인 유사도 방법으로 이동 궤적, 액션 위치, 죽은 위치를 비교 분석하였다. 분석 결과 사람과의 유사도가 0.9 이상인 인공지능 에이전트를 찾을 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.283-284
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• 2021

국내외 IoT(Internet of Things) 기반의 자동화 산업이 눈부시게 발전하고 있으며, 이러한 자동화 기술의 발전은 센서기술의 발전으로 더욱 가속화되고 있다. 최근에는 다양한 센서기술을 토대로 작물 재배를 목적으로 하는 스마트팜 산업이 급속하게 발전하고 있다. 스마트팜의 경우 작물 재배에 필요한 온도, 습도, CO2 등과 같은 대표적인 환경데이터를 계측하여 실시간 모니터링 및 모바일 서비스까지 제공하고 있다. 이러한 환경 모니터링 및 제어 동작의 대부분은 RS-485 기반의 모드버스(RTU) 통신방식을 활용하고 있다. 본 논문에서는 스마트팜 구축에 필요한 센서 데이터 및 액추에이터 정보를 IoT 표준 프로토콜인 MQTT(Message Queuing Telemetry Transport)를 사용하여 센서 데이터 및 액추에이터의 제어 동작을 LabView를 기반으로 플랫폼을 구축하여 성능을 테스트하고자 한다.

• 항공우주기술
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• 제9권2호
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• pp.153-160
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• 2010

ADRS는 프로그램 가능한 자동화 컨트롤러로써 스마트무인기를 위해 설계된 저비용의 재구성 가능한 비행시험 데이터 수집 시스템이다. 본 논문에서는 하드웨어와 소프트웨어 설계내용을 기술하였다. ADRS와 DFCC 인터페이스, ADRS와 센서 인터페이스에 대한 하드웨어 구성과 수정사항을 기술하였으며 ADRS 운용 소프트웨어와 데이터 저장에 대한 절차가 설명되었다. 마지막으로 스마트무인기의 지상시험과정을 통한 ADRS의 검증과정 및 결과가 제시되었다.