• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.172-180
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• 2011

When it essentially designs and develops the Railway Signal System H/W and S/W, It requires base to build an environment which the safety of the complete system can be certified objectively. It is not rational choice to progress the safety certification of each of the subsystems to ensure reliability from an economic point of view. Furthermore, Even though H/W and S/W already certificated the safety, In case of changing subsystem to comprise relevant system, The safety certification of its parts newly must proceed. This study to solve these problems covers safety H/W platform which is commonly applicable to composition plan at Ground railway signaling systems such as CBTC, ETCS, CBI and safety-based modeling approach with S/W development tools (SCADE) and certificated O/S (Pike) to build the development environment. In addition, When it designs and develops safety S/W, This study explains structure to separate the data section which for logical operations and logical operations itself and provides guideline to support the certification through minimizing changes to the software.

• 한국안전학회지
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• 제6권2호
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• pp.21-30
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• 1991

In this paper, we study effect of waveness at the optical surface roughness measurement. In generally, waveness components cause errors in calculation of the roughness value of metal surface. We study about surface roughness signals In the frequency domain for separate two signal component of real roughness and waveness by digital signal processing methods. Thereafter, determine low and high Component of frequency spectrum. By this separating frequency value we design liner low and high pass filter which cutoff frequency is 1 Hz. After this process, converted each filtered spectrum by inverse discrete fourier transformation to time domain waveness and real roughness signals We calculate surface roughness value from filtered roughness signals. For evaluate this method, we use five specimens roughness signal which obtained from optical surface roughness measuring system in 3mm/s moving speed with 0.1 mm laser beam spot size As a result, we obtain more linerized roughness value than that of unfiltered roughness signals.

• 전기학회논문지
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• 제65권11호
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• pp.1894-1899
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• 2016

In this paper, because the position sensor represents the important factor in BLDC (Brushless DC) motor drives, BLDC motor is necessary that the three Hall-sensors evenly be distributed around the stator circumference in case of the 3 phase motor. The Hall-sensor is set up in this motor to detect the main flux from the rotor. So the output signal from Hall-sensor is used to drive IGBT to control the stator winding current. However, in case of breakdown Hall sensor, we research that the estimation algorithm of Hall sensor signal to detect rotor position and for the speed feedback signals with BLDC motor whose six stator and two rotor designed. In addition, this paper presents a sensorless speed control of BLDC Motor using terminal voltage of the one phase. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three terminal voltages for a three-phase BLDC motor.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1054-1060
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• 2010

LRT(Light Rail Transit) is currently adopting a more upgraded signal system these days. This latest signal system is a train on-board signal system with moving block based on the realtime bi-directional wireless communications. The system applies RF-CBTC(Radio Frequency - Communication Based Train Control System) in order th execute fully automated manless operation. This paper reviews the performance requirements and safety of RF-CBTC that will be applied to the fully automated manless operation for LRT.

• 한국정보통신학회논문지
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• 제20권4호
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• pp.739-746
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• 2016

철도 안전사고 예방을 목표로 하는 실시간 철도 안전관제 시스템에서는 DDS (Data Distribution Service) 표준 기술 기반의 데이터 전송 방안을 적용함으로 기존 현장의 안전검지장치로부터 발생한 데이터를 통합 및 관리하고 있다. 본 논문에서는 수많은 현장 데이터 중 일반철도 현장에서 발생한 신호설비 데이터 규격 설계를 소개하고 있다. 신호설비 데이터의 DDS 전송을 위하여 기존 표준 규격인 KRS SG 0062를 모델링하고, DDS 데이터 전송 단위인 Topic 설계 및 데이터 변환 방안을 제시하고, 데이터 성격 별로 네트워크 제어 QoS 정책 설계를 제시하고 있다. 또한 실제 현장 데이터를 분석하여 설계된 규격이 현장에 적용 가능한지를 확인해 보았다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.375-378
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• 2017

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류안전 보안 핵심기술 개발이 이루어지고 있다. 또한 미국에서 2018년 시행예정인 컨테이너 사전 100% 전수검사에 대응하기 위한 컨테이너 검색기의 핵심구성 요소인 Array 검출 System의 국산화 개발이 필요하다. 본 논문에서는 현재 해외제품을 대체할 Array 검출 system 중 자체 개발한 Digital Signal Processing Board에 대한 연구를 제안하고자 한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권2호
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• pp.101-111
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• 2008

Good diagnostics improves both the safety and system unavailability of digital safety systems. The measure of a diagnostic capability is called the Coverage Factor. Because the Failure Modes, Effects and Diagnostic Analysis (FMEDA) provides information on the failure rates and failure mode distributions necessary to calculate a diagnostic coverage factor for a component, the FMEDA can be used as a useful tool to calculate it. Through performing FMEDA on a digital signal processor (DSP) board used in a digital safety system, it is shown that some components of the DSP board can be replaced or improved to satisfy the required diagnostic coverage. That is, the FMEDA can serve as a useful verification tool to design a diagnostic capability for the DSP board.

• 전기학회논문지
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• 제65권8호
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• pp.1442-1449
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• 2016

This paper proposes a diagnosis to detecting poor contact fault and fault location. Electrical fire by poor contact fault of power cable occupied a large proportion in the total electrical installations. The proposed method has an object to prevent electrical fault in advance. But detecting poor contact fault is difficult to detect fault type and fault location by using conventional reflectometry due to faults generated intermittently and repeatedly on the time change. Therefore, in this paper poor contact fault and fault conditions were defined. System generating poor contact fault produced for the experimental setup. SSTDR and algorithm of reference signal elimination heighten performance detecting poor contact fault on live power cable. The diagnosis methods of signal process and analysis of reflected signal was proposed for detecting poor contact fault and fault location. The poor contact fault and location had been detected through proposed diagnosis methods. The fault location and error rate of detection were verified detecting accuracy by experiment results.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.23-28
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• 2022

The eLoran system is a high-power terrestrial navigation system that is recognized as the most appropriate alternative to complement the GNSS's vulnerability to radio frequency interference. Accordingly, Korea has conducted eLoran technology development projects since 2016. The eLoran system developed in Korea provides 20 m positioning accuracy to maritime user in Incheon and Pyeongtaek harbor. To accurately calculate the position with the eLoran signal, it is necessary to apply a compensation method that mitigates the propagation delay. In this paper, we develop the compensation method to mitigate the eLoran signal propagation delay and evaluate the positioning performance in Incheon harbor. The propagation delay due to the terrain characteristics is pre-surveyed and stored in the user receiver. Real-time fluctuations in propagation delay compared to the pre-stored data are mitigated by the temporal correction generated at a nearby differential Loran station. Finally, two performance evaluation tests were performed to verify the positioning accuracy of the Korean eLoran system. The first test took place in December 2020 and the second in April 2021. As a result, the Korean eLoran service has been confirmed to provide 20 m location accuracy without GPS.

• 자동차안전학회지
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• 제8권1호
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• pp.19-25
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• 2016

As new car technology is developing, temporal interaction is needed in automotive. Rhythmic pattern is one of the practical examples of temporal interaction in vehicle. To recognize rhythmic pattern and its input medium, dictionary learning is applicable algorithm. In this paper, performance and memory requirement of the learning algorithm is tested and is sufficiently good for use this acoustic sound.