• 조명전기설비학회논문지
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• 제20권9호
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• pp.103-109
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• 2006

This research is contents about output characteristic of optic current sensor that use faraday effect. optic current sensor used in an experiment is consisted of three parts.(1) Source of light used laser diode of 1310[nm].(2) Sensor section manufactured circularly according to gas insulated switchgear. And $9/125[{\mu}m]$ standard single mode optical fiber for communication was installed winding 20 [turn] on sensor section core surroundings of diameter 31 [cm].(3) Electrical signal of PD(Photo detector) is collected using NI company's 16bit DAQ board via terminal block. Collected data analyzed by different three signal processing methods. NI company's $Labview^{TM}$ was used to signal processing software. As a result, In signal processing of optic current sensor, we could know that noise greatly more influences the error generation than fluctuation of light intensity. also, 1 class CT(current transformer) manufacture that have error rate less than 1[%] was available by removing these

• 한국유체기계학회 논문집
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• 제10권6호
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• pp.50-56
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• 2007

In this study, we have performed some experimental works on the effects of variation of low, middle and high turbidity for understanding of optical characteristics which is very important factor for the turbidity measurement. The various output frequencies were obtained by the experimental apparatus which consist of detectors, a light source, a frequency counter and so on. From the result of analysis of these frequencies, Firstly, The difference of signal value for each degrees of low turbidity was the smallest of three scopes around the Nephelometric position. Second, the characteristics of each degrees of middle turbidity was proved that signal values of all degrees were larger those of low turbidity but the difference of each signal value of the forward direction was smaller than that of the backward direction. Third, the characteristics of each degrees of high turbidity was proved that though similar to the characteristics of middle turbidity, each signal value of all degrees was larger and the difference of each signal value of all degrees was smaller than those of low and middle turbidity

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1117-1118
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• 2008

The LightScribe Technology is for printing images on the label side of recordable media using CD laser diode. By implementing Optimum Labeling Power Calibration for LightScribe, Labeling Quality can be improved. This paper proposes a new laser power calibration method using RFSUM signal. This function is implemented based on GH22LP20 of LG Electronics.

• Journal of the Optical Society of Korea
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• 제16권1호
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• pp.1-5
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• 2012

This paper describes a 150-Mb/s monolithic optical receiver for plastic optical fiber link using a standard CMOS technology. The receiver integrates a photodiode using an N-well/P-substrate junction, a pre amplifier, a post amplifier, and an output driver. The size, PN-junction type, and the number of metal fingers of the photodiode are optimized to meet the link requirements. The N-well/P-substrate photodiode has a 200-${\mu}m$ by 200-${\mu}m$ optical window, 0.1-A/W responsivity, 7.6-pF junction capacitance and 113-MHz bandwidth. The monolithic receiver can successfully convert 150-Mb/s optical signal into digital data through up to 30-m plastic optical fiber link with -10.4 dBm of optical sensitivity. The receiver occupies 0.56-$mm^2$ area including electrostatic discharge protection diodes and bonding pads. To reduce unnecessary power consumption when the light is not over threshold or not modulating, a simple light detector and a signal detector are introduced. In active mode, the receiver core consumes 5.8-mA DC currents at 150-Mb/s data rate from a single 3.3 V supply, while consumes only $120{\mu}W$ in the sleep mode.

• 한국광학회지
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• 제16권4호
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• pp.319-325
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• 2005

고속으로 간섭피크의 위치를 찾기 위해 일련의 아날로그 신호처리를 수행하는 백색광간섭(WLI)센서용 신호처리 방식을 고안하고, 이를 WLI 온도센서 시스템에 적용하였다. 새로운 신호처리방식을 적용한 결과 잡음은 $0.019^{\circ}C/\sqrt{Hz}$로 측정되었으며, 선형성도 우수하였다. 그러나 보상용 간섭계에서의 온도변화가 센서출력의 드리프트로 나타났으며, 현재의 구성에서 드리프트의 온도 의존성은 $1.42{\mu}m/^{\circ}C$인 것으로 계산되었다. 또한 간섭피크간 간격이 광원의 가간섭길이에 비해 충분히 넓지 않은 경우 간섭무늬 피크의 간격과 신호처리기가 측정한 피크 간격과의 관계가 비선형적으로 나타날 수 있음도 확인하였다.

• 천문학회보
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• 제37권2호
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• pp.218.2-218.2
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• 2012

In the remote sensing researches, the reflected bright source such as snow, cloud have effects on the image quality of wanted signal. Even though those signal from bright source are adjusted in corresponding pixel level with atmospheric correction algorithm or radiometric correction, those can be problem to the nearby signal as one of the stray light source. Especially, in the step and stare observational method which makes one mosaic image with several snap shots, one of target area can affect next to the other snap shot each other. Presented in this paper focused on the stray light analysis from unwanted reflected bright source for geostationary ocean color sensor. The stray light effect for total 16 slot images each other were performed according to 8 band filters. For the realistic simulation, we constructed system modeling with integrated ray tracing technique which realizes the same space time in the remote sensing observation among the Sun, the Earth, and the satellite. Computed stray light effect in the results of paper demonstrates the distinguishable radiance value at the specific time and space.

• 융합신호처리학회논문지
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• 제22권3호
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• pp.104-109
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• 2021

본 논문에서는 self-seeding FP-LD (Fabry Perot Laser Diode)를 이용하여 WDM-PON (Wavelength Division Multiplexing - Passive Optical Network)에서 사용될 수 있는 새로운 파장 가변 광원의 가능성을 검증한다. 파장 가변 광원을 이용한 WDM-PON의 기존 구현은 AWG (Arrayed Waveguide Grating) 소자의 중심 파장과 광원의 중심 파장을 세밀히 정렬해 주어야 하는 단점이 발생한다. 그러나, 본 논문에서 제안하는 파장 가변 광원은 매우 간단한 구조로 구성되며, 가변 파장이 AWG의 중심 파장에 자동 정렬되는 장점을 갖는다. 구현된 파장 가변 광원은 약 14 nm 정도 이상의 파장 가변 대역을 보였고, 상대적 세기 잡음, RIN (Relative Intensity Noise)은 최대 약 -124dB/Hz로 나타났으며, 외부 변조기를 통해 변조한 결과 10Gb/s 신호에 대한 변조 가능성을 확인 할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4268-4289
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• 2020

Advanced traffic signal timing method plays very important role in reducing road congestion and air pollution. Reinforcement learning is considered as superior approach to build traffic light timing scheme by many recent studies. It fulfills real adaptive control by the means of taking real-time traffic information as state, and adjusting traffic light scheme as action. However, existing works behave inefficient in complex intersections and they are lack of feasibility because most of them adopt traffic light scheme whose phase sequence is flexible. To address these issues, a novel adaptive traffic signal timing scheme is proposed. It's based on actor-critic reinforcement learning algorithm, and advanced techniques proximal policy optimization and generalized advantage estimation are integrated. In particular, a new kind of reward function and a simplified form of state representation are carefully defined, and they facilitate to improve the learning efficiency and reduce the computational complexity, respectively. Meanwhile, a fixed phase sequence signal scheme is derived, and constraint on the variations of successive phase durations is introduced, which enhances its feasibility and robustness in field applications. The proposed scheme is verified through field-data-based experiments in both medium and high traffic density scenarios. Simulation results exhibit remarkable improvement in traffic performance as well as the learning efficiency comparing with the existing reinforcement learning-based methods such as 3DQN and DDQN.

• 한국항행학회논문지
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• 제23권1호
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• pp.61-68
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• 2019

블랙박스 본체를 회수하지 않고도 블랙박스의 정보나 수중 장비의 기록된 정보 등을 회수할 수 있도록 빛을 이용하는 수중 무선 광 통신 시스템은 매우 요긴하다. 본 논문에서는 탁도가 높은 천해환경에서 수중 가시광 통신시 발생하는 노이즈 원인을 분석하고 이러한 환경에서도 노이즈를 효과적으로 제거하면서도 광 검출신호의 최대 전압 스윙을 향상시킬 수 있는 기준신호 기반의 광 검출 센서 기술을 연구하였다. 그리고 개발한 통신 시스템의 성능을 입증하기 위해 광 무선통신 시스템을 제작하고 탁한 해수가 담긴 수조에서 송수신 시험을 수행하여 개발한 광 무선통신 기법이 실제로 효과가 있음을 검증하였다.

• 한국멀티미디어학회논문지
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• 제9권12호
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• pp.1628-1635
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• 2006

A new frequency-modulated m-sequence correlation technique was described. It has. been seen that the frequency modulation scheme leads to higher signal-to-noise ratio than direct sequencing and less hardware effort than PSK modulation scheme. The operating frequency of the correlation system was deduced. The optimal frequency for the frequency-modulated m-sequence correlation system should be 1.35 times of the center frequency of the transducer. The application of this correlation technique to electromagnetic ultrasonic system was computer-simulated.