• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.657-663
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• 2016

In this work, a novel silicon (Si) based floating body synaptic transistor (SFST) is studied to mimic the transition from short-term memory to long-term one in the biological system. The structure of the proposed SFST is based on an n-type metal-oxide-semiconductor field-effect transistor (MOSFET) with floating body and charge storage layer which provide the functions of short- and long-term memories, respectively. It has very similar characteristics with those of the biological memory system in the sense that the transition between short- and long-term memories is performed by the repetitive learning. Spike timing-dependent plasticity (STDP) characteristics are closely investigated for the SFST device. It has been found from the simulation results that the connectivity between pre- and post-synaptic neurons has strong dependence on the relative spike timing among electrical signals. In addition, the neuromorphic system having direct connection between the SFST devices and neuron circuits are designed.

• 한국유체기계학회 논문집
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• 제15권1호
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• pp.52-57
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• 2012

Stall inception characteristics are researched to understand stall well. To realize different stall inception patterns, IGV stagger angle was changed. At design IGV stagger angle, spike, which is short length scale, is observed. Decreasing IGV stagger angle, spike changes to mode, which is long length scale, and further decreasing get multi cell. Compressor maps for each IGV stagger are shown to compare different stall inceptions. The characteristics of both spike and mode are confirmed in this experiment. Furthermore, transient from spike to mode is find. multi cell has 4cells and is little bit faster than mode. and multi cell shows 2nd, 3rd characteristics on compressor map.

• The Korean Journal of Physiology and Pharmacology
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• 제21권5호
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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.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권6호
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• pp.658-663
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• 2015

In the previous work, we have proposed an integrate-and-fire neuron circuit and synaptic device based on the floating body MOSFET [1-3]. Integrate-and-Fire(I&F) neuron circuit emulates the biological neuron characteristics such as integration, threshold triggering, output generation, refractory period using floating body MOSFET. The synaptic device has short-term and long-term memory in a single silicon device. In this paper, we connect the neuron circuit and the synaptic device using current mirror circuit for summation of post synaptic pulses. We emulate spike-timing-dependent-plasticity (STDP) characteristics of the synapse using feedback voltage without controller or clock. Using memory device in the logic circuit, we can emulate biological synapse and neuron with a small number of devices.

• 한국작물학회지
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• 제33권3호
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• pp.270-280
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• 1988

피맥의 다수확을 위하여는 다비, 밀식재배를 하여야 하며 이때에 문제가 되는 것은 도복에 의한 감수이다. 이러한 중요성에 비추어 피맥 7개 조합을 공시하여 간장과 수장의 대응이 되는 isogenic lines 을 만들어 다비, 밀식재배조건하에서 간장 및 수장의 차이에 따른 유전자의 주효과와 다면적효과를 구명하고 농업형질에 미치는 영향을 알아 양질 다수성 품종육성을 위한 기초자료를 얻고저 시험하였는바 그 결과를 요약하면 다음과 같다. 1. 간장동질유전자계통에서 단간계통 대 중간계통, 수장동질유전자계통에서 단수계통 대 중수계통, 간장과 수장 동질유전자계통에서 단간단수계통 대 중간중수계통, 단간단수계통 대 장간장수계통간에는 간장 및 수장의 주효과와 다면적 효과에 고도의 유의성을 보였다. 2. 간장동질유전자계통에서 간장유전자의 영향이 큰 형질은 출수일수, 제1, 2절간장, 수당립수, m$^2$당 수수, 1$\ell$중이었고 수장동질유전자계통에서 수장유전자의 영향이 큰 형질은 수축절수, 출수일수, 성숙일수, 1,000립중, 1$\ell$중이었다. 3. 간장 및 수장동질유전자계통에서 간장 및 수장유전자가 복합적으로 영향을 주는 형질은 수축절수, 제 2, 3, 4 절간장, 1,000립중 및 수량이었다. 4. 수량은 단간계통이 중간계통보다, 중수계통이 단수계통보다, 중간중수계통이 단간단수계통보다, 단간단수계통이 장간장수계통보다 많은 경향이며 성숙일수는 단간계통이 중간계통보다, 중수계통이 단수계통보다, 단간단수계통이 중간중수계통보다 짧은 경향이었다.

• 전자공학회논문지S
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• 제35S권2호
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• pp.70-78
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• 1998

Spike detection in long-term EEG monitoring forepilepsy by wavelet transform(WT), artificial neural network(ANN) and the expert system is presented. First, a small set of wavelet coefficients is used to represent the characteristics of a singlechannel epileptic spikes and normal activities. In this stage, two parameters are also extracted from the relation between EEG activities before the spike event and EEG activities with the spike. then, three-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained from the first stage. Spikes are identified in individual EEG channels by 16 identical neural networks. Finally, 16-channel expert system based on the context information of adjacent channels is introducedto yield more reliable results and reject artifacts. In this study, epileptic spikes and normal activities are selected from 32 patient's EEG in consensus among experts. The result showed that the WT reduced data input size and the preprocessed ANN had more accuracy than that of ANN with the same input size of raw data. Ina clinical test, our expert rule system was capable of rejecting artifacts commonly found in EEG recodings.

• Animal Systematics, Evolution and Diversity
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• 제36권2호
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• pp.164-166
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• 2020

Herein, we report a new record of Notodontidae moth, Neodrymonia marginalis (Matsumura) in Korea. This species is characterized by grayish forewing that shows thick dark grayish band between basal and antemedial line, smooth postmedial line costally with blackish crescent line, dark grayish subtermen with dark brownish thick band costally, and whitish and black dot shaped discal dot. The female genitalia can be distinguished by the broad, plate-shaped postvaginalis, strongly sclerotized ductus dursae with three long spike shaped and several small spike shaped processes, and large, ovate corpus bursae with a large fan-shaped plate signum. Neodrymonia marginalis can be distinguished from N. deliana by the shape and color of the costal part of postmedial line and subtermen of forewing. The female genitalia of N. marginalis can be distinguished from those of N. deliana by the rectangular postvaginalis and more spike like processes of the anterior of ductus bursae. Up to now, four species of Neodrymonia are recorded in Korea: N. delia (Leech, 1889), N. coreana Matsumura, 1922, N. deliana Gaede, 1933, and Neodrymonia marginalis.

• Animal cells and systems
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• 제13권4호
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• pp.357-362
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• 2009

Hesperidin, the most abundant polyphenolic compound found in citrus fruits, has been known to possess neuroprotective, sedative, and anticonvulsive effects on the nervous system. In a recent electrophysiological study, it was reported that hesperidin induced biphasic change in population spike amplitude in hippocampal CA1 neurons in response to both single spike stimuli and theta-burst stimulation depending on its concentration. However, the precise mechanism by which hesperidin acts on neuronal functions has not been fully elucidated. Here, using whole-cell patch-clamp recording, we revealed that hesperidin did not affect excitatory synaptic activities such as basal synaptic transmission and theta-burst LTP. Moreover, in a current injection experiment, spike number, resting membrane potential and action potential threshold also remained unchanged. Taken together, these results indicate that the effects of hesperidin on the neuronal functions such as spiking activity might not be attributable to either modification of excitatory synaptic transmissions or changes in membrane excitability in hippocampal CA1 neuron.

• The Korean Journal of Physiology and Pharmacology
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• 제3권2호
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• pp.119-125
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• 1999

Mammalian gastric smooth muscles generate spontaneous rhythmic contractions which are associated with slow oscillatory potentials (slow waves) and spike potentials. Spike potentials are blocked by organic $Ca^{2+}-antagonists,$ indicating that these result from the activation of L-type $Ca^{2+}-channel.$ However, the cellular mechanisms underlying the generation of slow wave remain unclear. Slow waves are insensitive to $Ca^{2+}-antagonists$ but are blocked by metabolic inhibitors or low temperature. Recently it has been suggested that Interstitial Cells of Cajal (ICC) serve as pacemaker cells and a slow wave reflects the coordinated behavior of both ICC and smooth muscle cells. Small segments of circular smooth muscle isolated from antrum of the guinea-pig stomach generated two types of electrical events; irregular small amplitude (1 to 7 mV) of transient depolarization and larger amplitude (20 to 30 mV) of slow depolarization (regenerative potential). Transient depolarization occurred irregularly and membrane depolarization increased their frequency. Regenerative potentials were generated rhythmically and appeared to result from summed transient depolarizations. Spike potentials, sensitive to nifedipine, were generated on the peaks of regenerative potentials. Depolarization of the membrane evoked regenerative potentials with long latencies (1 to 2 s). These potentials had long partial refractory periods (15 to 20 s). They were inhibited by low concentrations of caffeine, perhaps reflecting either depletion of $Ca^{2+}$ from SR or inhibition of InsP3 receptors, by buffering $Ca^{2+}$ to low levels with BAPTA or by depleting $Ca^{2+}$ from SR with CPA. They persisted in the presence of $Ca^{2+}-sensitive$ $Cl^--channel$ blockers, niflumic acid and DIDS or $Co^{2+},$ a non selective $Ca^{2+}-channel$ blocker. These results suggest that spontaneous activity of gastric smooth muscle results from $Ca^{2+}$ release from SR, followed by activation of $Ca^{2+}-dependent$ ion channels other than $Cl^-$ channels, with the release of $Ca^{2+}$ from SR being triggered by membrane depolarization.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.199-199
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• 2017

This study investigated the aspects of damage due to low temperature treatment in order to establish the damage criterion according to low temperature invasion during regeneration period in wheat after regeneration period in the early spring. We cultivated wheat cultivar 'Geumgang' in Wagner pots and treated them with three types of low temperature, and the gradual temperature change program was set in a low temperature incubator for 12.5 h per day for 5 days during the night time when the length of young spikes was about 1 mm. All treatments except for the control were treated in 5 steps for each temperature. Treatment 1 was treated at the lowest temperature $-5^{\circ}C$ for 5 h, treatment 2 for 7 h at $-5^{\circ}C$, and treatment 3 for 9 h at $-5^{\circ}C$. The most common type of damage was partial infertility, and there were some discolored spikes. The damage rate of wheat spikes treated at $-5^{\circ}C$ for 9 h was the highest, while the damage rates of wheat sprouts treated at 5h and 7h were not different from each other. It was found that the damage of wheat spikes exposed to low temperatures for a long time was large. It is necessary to investigate the aspects of spike damage by duration days of low temperature.