• 한국항행학회논문지
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• 제20권4호
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• pp.298-304
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• 2016

본 논문은 초음파 거리계를 이용하는 쿼드로터 무인항공기의 고도 제어 성능 향상을 위한 웨이블릿 패킷 변환 기법을 제시하였다. 쿼드로터의 수직 이착륙 시 많이 사용되는 초음파 거리계를 이용하여 지상시험을 수행하였다. 초음파 거리계는 정반사율 (specular reflectance)과 음향 잡음 (acoustic noise)으로 인한 신호의 스파이크가 생긴다. 짧은 시간 간격으로 발생하는 스파이크는 시간과 주파수 영역에서의 동시 분석을 필요로 한다. 이에 초음파 거리계의 스파이크를 웨이블릿 패킷 변환을 이용하여 분석하였다. DWT (discrete wavelet transform)에 비해 웨이블릿 패킷 분해가 더 풍부한 시간-주파수 국소 정보를 얻을 수 있어 초음파 신호의 스파이크를 분석하고 처리하기에 더 효과적이다. 실험결과 초음파 거리계의 스파이크를 효과적으로 제거할 수 있음을 확인하였다.

• 센서학회지
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• 제30권4호
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• pp.196-203
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• 2021

In this study, an optical identification system was developed, wherein visible light is used to transmit the interrogating signal, and infrared is used to send the response signal. In the reader, visible light from a light emitting diode (LED) array was modulated via modified pulse width modulation for flicker-free illumination and dimming control. Moreover, the duty factor of the dimming control time was employed to control the illumination from the LED. In the transponder, the spike signal in the output of the high-pass filter was utilized to recover the interrogating signal while preventing interference from the 120-Hz noise from adjacent lighting lamps. The illumination was controlled in 26-86% range of the constant wave LED illumination by changing the duty factor from 20% to 90%. This configuration is advantageous for the construction of optical identification systems for automatic security check and car fare calculation at toll gates or parking facilities.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.23-23
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• 2001

To evaluate the contribution of cAMP/PKA signal pathway in short-term facilitation, we overexpressed Ap oal receptor in sensory neurons that do not normally express this receptor. We have previously shown that activation of this receptor in sensory cells, by a brief treatment with octopamine (OA), produced short-term facilitation such as membrane depolarization, increase in membrane excitability, spike broadening, and enhanced neurotransmitter release in non-depressed synapse.(omitted)

• 한국동물위생학회지
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• 제44권2호
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• pp.73-83
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• 2021

Although many swine farms continuously vaccinated to sow to prevent Porcine epidemic diarrhea(PED), PED has occurred annually in swine herds in Jeonbuk province, Korea. In the present study, the small intestine and feces samples from 17 farms where severe watery diarrhea and death of newborn piglets occurred in 2019 were collected, amplified by RT-PCR and determined the complete nucleotide sequences of the spike (S) glycoprotein genes of nine Jeonbuk PEDV isolates. The spike (S) glycoprotein is an important determinant for molecular characterization and genetic relationship of PEDV. These nine complete S gene isolates were compared with other PEDV reference strains to identify the molecular diversity, phylogenetic relationships and antigenicity analysis. 9 field strains share 98.5~100% homologies with each other at the nucleotide sequence level and 97.3~100% homologies with each other at the amino acid level. The nine Jeonbuk PEDV isolates were classified into G2b group including a genetic specific signal, S-indels (insertion and deletion of S gene). In addition, comparisons the neutralizing epitopes of S gene between 9 field strains and domestic vaccine strains of Korea mutated 12-15 amino acids with SM-98-1 (G1a group) and mutated 0-3 amino acids with QIAP1401 (G2b group). Therefore, the development of G2b-based live vaccines will have to be expedited to ensure effective prevention of endemic PED in Korea. In addition, we will need to be prepared with periodic updates of preventive vaccines based on the PEDV variants for the re-emergence of a virulent strain.

• 한국항행학회논문지
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• 제20권3호
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• pp.196-202
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• 2016

본 논문은 초음파 거리계를 이용하는 쿼드로터 무인항공기의 고도 제어 성능 향상을 위한 정상 웨이블릿 변환 기법을 제시하였다. 쿼드로터의 수직 이착륙 시 많이 사용되는 초음파 거리계를 이용하여 지상시험을 수행하였다. 초음파 거리계는 정반사율(specular reflectance)과 음향 잡음 (acoustic noise)으로 인한 신호의 스파이크가 생긴다. 짧은 시간 간격으로 발생하는 스파이크는 시간과 주파수 영역에서의 동시 분석을 필요로 한다. 정상 웨이블릿 변환은 DWT (discrete wavelet transform)에서 다운샘플링에 의해 발생하는 문제점을 해결하기 위한 변환방법으로써 잡음제거에 DWT보다 효과적이라고 알려져 있다. 이에 초음파 거리계의 스파이크를 정상 웨이블릿 변환 기법을 이용하여 분석하였고, 실험결과 초음파 거리계의 스파이크를 효과적으로 제거할 수 있음을 확인하였다.

• 한국소프트웨어감정평가학회 논문지
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• 제17권2호
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• pp.47-57
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• 2021

뉴로모픽 기술은 인간의 뇌 구조와 연산과정을 하드웨어로 모방하는 기술로 기존 인공지능 기술의 단점을 보완하기 위하여 제안되었다. 뉴로모픽 하드웨어 기반의 IoT 응용을 개발하기 위해 NA-IDE가 제안되었으며, NA-IDE에서 SNN 모델을 구현하기 위하여 일반적으로 많이 사용되는 입력 데이터를 SNN모델에 사용할 수 있도록 변환이 필요하다. 본 논문에서는 이미지 데이터를 SNN 입력으로 사용하기 위하여 스파이크 시계열 패턴으로 변환하는 신경코딩 방식의 인코더 컴포넌트를 구현하였다. 디코더 컴포넌트는 SNN 모델이 스파이크 시계열 패턴을 생성하는 경우, 출력된 시계열 데이터를 다시 이미지 데이터로 변환하도록 구현하였다. 디코더 컴포넌트는 출력 데이터에 인코딩 과정과 동일한 매개변수를 사용한 경우, 원본 데이터와 유사한 정적 데이터를 얻을 수 있었다. 제안된 인코더와 디코더를 사용한다면 image-to-image나 speech-to-speech와 같이 입력 데이터를 변환하여 재생성하는 분야에 사용할 수 있을 것이다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.55-58
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• 1997

In this paper, we study a signal processing method which extracts each MUAP(motor unit action potential) from EMG(Electromyogram) interference pattern or clinical diagnostic purposes. First of all, differential digital filtering is selected or eliminating the spike components of the MUAP's from the background noise. And, the algorithm identifies the spikes over the certanin threshold by template matching in frequency domain. After missing or false firing actor is cut off at the IPI(inter pulse interval) histogram, we averages the MUAP waveforms from the raw signal using the identified spikes as triggers, and Finally, measures their amplitudes, durations, and numbers of phases. Specially, We introduce algorithm performed by template matching in the frequency domain. A typical 3-s signal recorded from the biceps brachii muscle using a conventional needle electrode during a isometric contraction is used. Finally, the method decomposed five simultaneous active MUAP's from original EMG signal.

• 터널과지하공간
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• 제5권1호
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• pp.70-76
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• 1995

Two types of deformations can occur on the cable during the monitoring of the rock displacement by the time domain reflectometry. One is the impedance model for tensile deformation, and the other is the capacitance model for the shear deformation. The former gives a response signal with a gradual change in the amplitude of the reflected voltage, meanwhile the latter produces a signal with a blunted spike. The resolution of the TDR can be improved to 0.125% using calibration crimps on the cable of 60 meters long. It is recommended that the diameter of the cable should be 18 mm at least in order to induce a better reflected pulse without any open-circuit. The actual TDR technique cannot characterize the type and the magnitude of rock displacement quantitatively. Systematic investigation of the TDR parameters, such as the exact of cable diameter, cable length, number of crimps, combination of shearing and extension, and environment of the TDR equipment, will be able to improve the resolution to 0.01 mm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.257-259
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• 2002

In investigating the characteristics of a neural network, the use of planar microelectrode array shows several advantages over normal intracellular recording[1]. A transparent indium tin oxide(ITO) multi-electrode array(MEA) was fabricated and its top surface was insulated with photodefinable polyimide(HD-8001) except the exposed area for interfacing between the ITO electrodes and the neuronal cells. The exposed ITO electrodes were platinized in order to reduce the impedance between the electrodes and electrolyte. The one-minute platinization with $0.99nA/{\mu}m^2$ current density reduced the average impedance of the electrodes from $2.5M\Omega\;to\;90k\Omega$ at 1kHz in normal ringer solution. Cardiac cells were cultured on this MEA as a pilot study before neuron culture. The signals detected by the platinized electrodes had larger amplitudes and improved signal to noise ratio(SNR) compared to non-platinized electrodes. It is clear that microelectrodes need to have lower impedance to make reliable extracellular recordings, and thus platinization is essential part of MEA fabrication. Burst spike of cultured olfactory bulb was also detected with the MEA having platinized electrodes.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.174-179
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• 2017

We designed the CMOS analog integrate and fire (I&F) neuron circuit for driving memristor based on resistive-switching random access memory (RRAM). And we fabricated the RRAM device that have $HfO_2$ switching layer using atomic layer deposition (ALD). The RRAM device has gradual set and reset characteristics. By spice modeling of the synaptic device, we performed circuit simulation of synaptic device and CMOS neuron circuit. The neuron circuit consists of a current mirror for spatial integration, a capacitor for temporal integration, two inverters for pulse generation, a refractory part, and finally a feedback part for learning of the RRAM. We emulated the spike-timing-dependent-plasticity (STDP) characteristic that is performed automatically by pre-synaptic pulse and feedback signal of the neuron circuit. By STDP characteristics, the synaptic weight, conductance of the RRAM, is changed without additional control circuit.