• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.17-26
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• 2007

Because the prime objective of the current preemption methods at signalized intersections near highway-railroad grade crossings(IHRGCs) is to clear the crossing, secondary objectives such as safe pedestrian crossing time and minimized delay often are given less consideration or are ignored completely during the preemption. Under certain circumstances state-of-the-practice traffic signal preemption strategies may cause serious pedestrian safety and efficiency problems at IHRGCs. An improved transition preemption strategy(ITPS) that is specifically designed to improve intersection performance while maintaining or improving the current level of safety was developed by Cho and Rilett. Even if the new transition preemption strategy improved both the safety and efficiency of IHRGCs, the performance of the strategy is affected by train speed. Understanding the impact of this factor is essential in order to implement ITPS. In this paper, the effects of train speed were analyzed using a VISSIM simulation model which was calibrated to field conditions. It was concluded that the delay is affected more by train speed than the transitional preemption strategy and the safety of the intersection is not affected by train speed once an advanced preemption warning time(APWT) is equal to or greater than 90 seconds.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.490-495
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• 2016

Pulsed eddy current (PEC) testing signals have typically been obtained from the electromotive force induced in a sensor coil. However, an increasing number of studies have elected to incorporate the Hall plate as a sensor. Thus, accurate numerical modeling of the Hall sensor signal is necessary. In this study, a PEC probe is designed and a numerical modeling program is written so that Hall sensor signals and coil sensor signals can be calculated simultaneously. First, a step current is used as the input current. The predicted Hall sensor signals show similar characteristics to those of the experimental signals reported by other researchers. The characteristics of the two types of signals are then analyzed and compared as the thickness of test object changes. The results show that the Hall sensor signal provides less information for evaluating the thickness of the test object than the coil sensor signal. The response signals from a pulsed input current are also calculated, and it is confirmed that an equivalent reversed signal pattern appeared after the pulse width at both signals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10A
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• pp.969-979
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• 2002

This paper proposes an novel method of minimizing Interference which causes data decision error in digital wireless communications. In this method, in order to suppress ISI which is caused by the phase difference between the transmitted and received signal phases, the transmitted and received signals are always kept orthogonal by compensating the transmitted signal for detecting the phase noise and the delay of the received signal was implemented by MOS circuits. To delay the phase of the signal, additive white Gaussian noise (AWGN) environment was used. The phase and delay of the signal transmitted through AWGN channel were compensated in the modulator of the transmitter and the compensated signal was demodulated using quasi-direct conversion receiver and QPSK demodulator. ISI suppression was achieved by keeping the orthogonality between the compensated transmitted signal and the receive signal. The error probability of data decision was compared. By simulation the proposed system was proved to be effective in minimizing the ISI.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.29-35
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• 2013

In this paper, we investigate the type and detection methode of spoofing attack, and then analyze the performance of spoofing detection algorithm in GPS L1 signal through the simulation. Generally spoofer is different from the jammer, because the receiver can be operated and not. In case of spoofing the GPS receiver is hard to recognize the spoofing attack and can be operated normally without stopping because the spoofing signal is the mimic GPS signal. To evaluate the performance of spoofing detection algorithm, both the software based spoofing and GPS signal generator and the software based GPS receiver are implemented. In paper, we can check that spoofing signal can affect to the DLL and PLL tracking loop because code delay and doppler frequency of spoofing. The spoofing detection algorithm has been implemented using the pseudorange, signal strength and navigation solution of GPS receiver and proposed algorithm can effectively detect the spoofing signal.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.70-72
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• 1984

본 논문에서는 음성신호에 섞인 잡음을 효과적으로 제거하기 위해 Two-sided Transversal Filter를 이용하는 방법을 제시하였다. 이 방법은 기존의 방법과는 달리 신호의 단기자기상관관계(short-term autocorrelation)을 충분히 이용하기 위해 적응 필터의 입력으로, 지연된 신호뿐만 아니라 미래의 신호도 이용하도록 하였다. 이 결과 음성신호에 섞인 잡음(백색잡음, 유색잡음)을 아주 효과적으로 제거함을 알 수 있다.

• Information and Communications Magazine
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• v.9 no.6
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• pp.51-68
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• 1992

사용자 정보 전달을 위한 가상채널을 설정하는 신호절차는 B-ISDN에서도 매우 중요하다. 본 논문에서는 B-ISDN 서비스를 지원하는 B-ISDN 신호프로콜의 특성을 살펴보고, 각 부분별 즉, UNI, NNI, Meta-Signalling, SAAL(Signalling AAL)에 대해 설명한다. 그리고 B-ISDN 신호 절차 및 신호 프로토콜의 진화방향등을 살펴보고, 다양한 B-ISDN서비스특성을 만족시키기 위해 앞으로 연구되어야 할 신호 기능들을 기술하였다.

• ETRI Journal
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• v.6 no.2
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• pp.39-44
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• 1984

애널로그 신호인 음성신호를 디지틀값으로 변환하여 컴퓨터의 mass storage device에 저장하거나 또는 저장된 디지틀 음성 데이터를 애널로그 신호로 재생하는 기술은 디지틀 음성신호처리의 가장 중요한 토대를 마련해 준다. 본고에서는 음성변경시스팀과 같은 저장형 통신시스팀의 구현에 있어서 반드시 구비되어야 할 기술인 음성신호의 실시간 디스크 저장문제를 NOVA 4/X 미니컴퓨터에서 해결한 것을 간단히 기술하였다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.159-162
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• 1999

본 논문에서는 비선형 시계열 신호처리 및 분석을 위한 카오스 시뮬레이터에 대해서 소개한다. 이 시뮬레이터는 크게 세 개의모듈로 이루어져 있으며 신호발생 모듈, 신호처리 모듈, 신호분석 모듈로 나누어 진다. 이 카오스 시뮬레이터를 이용한 비선형 시계열 신호분석 결과 각각의 파라메터에 따른 신호분석이 가능함을 알 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.659-661
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• 1998

기존의 평판 디스플레이 비디오 신호 전송 방식은 그래픽 어댑터에 저장된 비디오 데이터를 DA컨버터를 통해 아날로그 신호를 전송한 다음 평판 디스플레이 패널에서 다시 AD 컨버터를 이용해 디지털 신호로 복원한 다음 평판 디스플레이용 컨트롤에 입력되었다. 아날로그 신호를 보내는 것은 AD/DA 컨버터를 이중으로 사용할 뿐 아니라, 연결선을 길게 하는 것이 어렵고 노이즈로 인해 데이터의 수치가 변할 우려가 있다. 패널의 고면적화와 고해상도의 기술 발달로 SXGA급 및 UXGA급 신호에서는 높은 클럭 주파수와 긴 연결선에서도 안정된 신호 전송을 할 수 있는 VESA FPDi 규격에 맞는 인터페이스는 노이즈에 강하고 전자파 발생 억제 및 저전력으로 동작을 한다. 본 논문에서는 인터페이스 신호 전송 방법을 연구하여 신호의 변화를 줄여서 전자파 발생 억제 및 저전력에 도움을 주는 비디오 신호 엔코딩 알고리즘을 제안하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11A
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• pp.1038-1044
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• 2010

Interference may severely deteriorate performance in wireless communication. Han-Kobayashi scheme splits each user's signal into private and common information so that the receiver removes the other's common signal for partial interference cancellation. This paper proposes an optimal power allocation to private and common signals for Han-Kobayashi scheme by using required SNR in a private information only system. Numerical results show that the proposed power allocation is quite close to the optimal power allocation based on exhaustive searches.