• Title/Summary/Keyword: spike detection

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Performance Evaluation of Speech Onset Representation Characteristic of Cochlear Implants Speech Processor using Spike Train Decoding (Spike Train Decoding에 기반한 인공와우 어음처리기의 음성시작점 정보 전달특성 평가)

  • Kim, Doo-Hee;Kim, Jin-Ho;Kim, Kyung-Hwan
    • Journal of Biomedical Engineering Research
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    • v.28 no.5
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    • pp.694-702
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    • 2007
  • The adaptation effect originating from the chemical synapse between auditory nerve and inner hair cell gives advantage in accurate representation of temporal cues of incoming speech such as speech onset. Thus it is expected that the modification of conventional speech processing strategies of cochlear implant(CI) by incorporating the adaptation effect will result in considerable improvement of speech perception performance such as consonant perception score. Our purpose in this paper was to evaluate our new CI speech processing strategy incorporating the adaptation effect by the observation of auditory nerve responses. By classifying the presence or absence of speech from the auditory nerve responses, i. e. spike trains, we could quantitatively compare speech onset detection performances of conventional and improved strategies. We could verify the effectiveness of the adaptation effect in improving the speech onset representation characteristics.

AUTOMATIC DETECTION OF EPILEPTIFORM ACTIVITY USING WAVELET AND ARTIFICIAL NEURAL NETWORK (웨이브렛과 신경회로망을 이용한 간질 파형 자동 검출)

  • Park, H.S.;Park, C.H.;Lee, Y.H.;Lee, D.S.;Kim, S.I.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.358-361
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    • 1997
  • This paper describes a multichannel epileptic seizure detection algorithm based on wavelet transform(WT), artificial neural network(ANN) and expert system. First, through the WT, a small number of wavelet coefficients is used to represent the single channel epileptic spike. Next, 3-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained above. Finally, 16 channel expert system which is based on clinical experience is introduced as a artifact rejection and reliable detection. The suggested algorithm was implemented on personal computer(PC). Two main events i.e., epileptiform and normal activities, were selected from 32 person's EEGs(normal: 20, seizure disorder: 12) in consensus among experts. The result was that WT reduced data input size and ANN detected 97 of the 100 EEGs containing definite spike - sensitivity of 97%. Expert rule system was capable of rejecting a wide variety of artifacts commonly found in EEG recordings. It also reduced false positive detections of ANN.

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The advantage of topographic prominence-adopted filter for the detection of short-latency spikes of retinal ganglion cells

  • Ahn, Jungryul;Choi, Myoung-Hwan;Kim, Kwangsoo;Senok, Solomon S.;Cho, Dong-il Dan;Koo, Kyo-in;Goo, Yongsook
    • The Korean Journal of Physiology and Pharmacology
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    • v.21 no.5
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    • pp.555-563
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    • 2017
  • Electrical stimulation through retinal prosthesis elicits both short and long-latency retinal ganglion cell (RGC) spikes. Because the short-latency RGC spike is usually obscured by electrical stimulus artifact, it is very important to isolate spike from stimulus artifact. Previously, we showed that topographic prominence (TP) discriminator based algorithm is valid and useful for artifact subtraction. In this study, we compared the performance of forward backward (FB) filter only vs. TP-adopted FB filter for artifact subtraction. From the extracted retinae of rd1 mice, we recorded RGC spikes with $8{\times}8$ multielectrode array (MEA). The recorded signals were classified into four groups by distances between the stimulation and recording electrodes on MEA (200-400, 400-600, 600-800, $800-1000{\mu}m$). Fifty cathodic phase-$1^{st}$ biphasic current pulses (duration $500{\mu}s$, intensity 5, 10, 20, 30, 40, 50, $60{\mu}A$) were applied at every 1 sec. We compared false positive error and false negative error in FB filter and TP-adopted FB filter. By implementing TP-adopted FB filter, short-latency spike can be detected better regarding sensitivity and specificity for detecting spikes regardless of the strength of stimulus and the distance between stimulus and recording electrodes.

LED Dimming Control Using Manchester-Code Duty Factor And Spike Detection in Visible Light Communication (가시광통신에서 맨체스터코드 듀티율과 스파이크 검출을 이용한 LED 조명제어)

  • Lee, Seong-Ho
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.571-579
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    • 2019
  • Visible light communication (VLC) performs illumination and communication simultaneously, thus it is important to prevent the flicker due to the optical power variation during data transmission and at the same time to have dimming control capability. In this paper, we used Manchester code for flicker-prevention and dimming control. In the transmitter, the duty factor of the Manchester code was used for controlling the LED illumination. In the receiver, the edge-spike signals of an RC-high pass filter were used for recovering the Manchester code while preventing the adjacent noise light. In experiments, the LED light was kept flicker-free and the average optical power was controlled in the range of 8~68 % of the continuous wave (CW) LED light by changing the duty factor of the Manchester code.

An implementation of automated ECG interpretation algorithm and system(II) - Estimation and Eliminator of interference components (심전도 자동 진단 알고리즘 및 장치 구현(II) - 잡음 성분 평가 및 제거기)

  • Kweon, H.J.;Kong, I.W.;Lee, S.H.;Shin, K.S.;Lee, M.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.283-287
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    • 1996
  • This paper described the estimator and eliminator far three kinds of artifacts in electrocardiogram. The most efficient estimation of baseline drift could be obtain in the cubic spline interpolation method with the PQ and TP segment which are considered to be isoelectric, from the experimental results obtained from the applied 4 types of algorithms. The time loss and distortion could be avoided with the aid of detection criteria by checking if baseline drifts exist or not. The AIEF proposed in this paper was verified as having the best removal performance with less distortion in the QRS complex through the comparison of 5 proposed algorithms. furthermore, the AIEF are most suitable far the ECG analyzer which was only needed relatively short time data due to the fast conversion into the stable state. The proposed parabolic filter with 11 points width was identified as having the best performance for the elimination of muscle artifacts. Also we could obtain 99.7% detection accuracy of spike component and minimize the error identifying QRS complex as spike.

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Detection and Classification of Extracellular Action Potential Using Energy Operator and Artificial Neural Network (에너지연산자와 신경회로망을 이용한 세포외신경신호외 검출 및 분류)

  • Kim, Kyung-Hwan;Kim, Sung-June
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.207-208
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    • 1998
  • Classification of extracellularly recorded action potential into each unit is an important procedure for further analysis of spike trains as point process. We utilize feedforward neural network structures, multilayer perceptron and radial basis function network to implement spike classifier. For the efficient training of classifiers, nonlinear energy operator that can trace the instantaneous frequency as well as the amplitude of the input signal is used. Trained classifiers shows successful operation, up to 90% correct classification was possible under 1.2 of signal-to-noise ratio.

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Spike Response Model and Coding of Neurons (뉴런의 스파이크 응답 모델과 코딩)

  • Lee, Ho-Suk
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.06b
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    • pp.5-8
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    • 2007
  • This paper discusses the spike response model of neurons. First, this paper discusses the coding of spikes, the function of spikes, and the construction of the spikes of neurons by the superposition of simple kernel functions. This paper discusses the method of kernel superposition is general than the response of the IF (Integrate-and-Fire) neuron model, too. Next, this paper discusses the coincidence detection and the input weight computation of spiking neurons and the activity of neuron populations in some detail.

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Determination of Sulfamethazine Using High Performance Liquid Chromatography and Several Screening Methods (HPLC 및 신속검출방법을 이용한 우유내 Sulfamethazine의 분석에 관한 연구)

  • 김철현;백승천;문지웅
    • Journal of Food Hygiene and Safety
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    • v.12 no.1
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    • pp.71-77
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    • 1997
  • Sulfonamides, a therapeutically important group of antimicrobial drugs, are widely used to treat and prevent the acute systemic and skin infections in dairy cattle. They also pose an economic hazard through inhibition of growth of dairy starter cultures. This study was carried out to compare four screening methods for detection of sulfamethazine in milk and determine the positive milk sample by HPLC method. Sulfamethazine was used to spike at five levels of sulfamethazine. The Lac-Tek test and CharmII test were also consistent better than TTCII test and Delvo SP test in sulfamethazine detection. Analysis probabilities of obtaining a positive response with TTCII test and Delvo SP test assay at 50 ppb sulfamethazine level in milk samples were only 14%, 42% each. Whereas using the Lac-Tek test and CharmII test would have resulted in 100% identification of the five levels. Determination of sufamethazine using the HPLC method in the spiked milk were 10.64, 19.30, 30.76,38.83 and 50.23 ppb, respectively.

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Improvement of Validity and Efficiency for Detection of Cryptosporidium Ocysts and Giardia Cysts in Environmental Water Samples (환경수 중 크립토스포리디움 오시스트 및 지아디아 시스트 검출의 정확도 및 회수율 향상을 위한 연구)

  • 이목영;조은주;김도연;변승헌;이의광;오세종;안승구
    • Korean Journal of Microbiology
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    • v.39 no.1
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    • pp.27-35
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    • 2003
  • No currently available methods to monitor pathogenic protozoa, Cryptosporidium and Giardia in environmental water come close to acceptable sensitivity, specificity and reproducibility, and so it has to be accompanied by thorough quality control and performance evaluation to credibly predict the distribution of them. We collected surface water samples from the Han River and spiked our prepared (oo)cysts, determined Matrix Spike recoveries using USEPA Method 1623 and considered what factors influence MS recovery and validity. As a result, average 46% of spiked oocysts and 60% of spike cysts were recovered, but repetitive sampling and statistical approach seemed to be necessary to determine the environmental pollution level of two protozoa as their variation coefficients was so much as 35oio and 26%. And MS recoveries with two acid dissociations during immunomagnetic separation were improved more 10% than that with one dissociations and the use of spiked suspension enumerated by flow cytometry instead of manual preparation enhanced the validity and reliability in spiking tests. Because fluorescence characteristics of (oo)cysts stained on well slides with FITC-labeled monoclonal antibodies and DAPI was not always same, well Elides from spiked field samples were helpful to evaluate the performance of staining. We found many (oo)cyst-like objects with typical fluorescence, not (co)cysts, from the Han River water samples, and then it was concluded that nuclei staining by DAPI (4',6-diamidino-2-phenylindole) and examination by Differential Interference Contrast Microscope should be critical for valid identification.

Highlight Detection Using Photometric Stereo and Object Reconstruction Using Difference Image (측광입체시법을 이용한 하이라이트 검출과 농담 차이를 이용한 물체 복원)

  • Bae, Cheol-Min;Mun, Yeong-Sik
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.4
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    • pp.1132-1140
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    • 1997
  • In many vision tasks of the major obstacles is the specular highkight of smoth objects, which causes a misinterpretation of objects.This paper presents an dffcient algorithm for highight detection and object reconstruction, blsed on the theory of photometric stereo in which the location of highilight changes as the position of illumination source changes.Two images, referred to as base image and reference image.are sequentially taken with two different positionhs of the two images.The difference image is thresholded to detct the specular spike of the highlight.Then the specu-lar lobe around the specular spike is detected to reconstruct the object.The proposed algorithm can be applied to metals and dielectrics, regardlless of the surface chracteristics.This method can also be aplied to the case when the background is brighter than the object.

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