• Analytical Science and Technology
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• v.27 no.6
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• pp.269-276
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• 2014

A short study for the uncertainty of post column isotope dilution method has been performed for the analysis of Selenomethionine in HPLC-ICP/MS. Major error sources studied were concentration and the flow rate of Se isotope solution, atomic weights of Se in spike and sample, and isotope ratio measured for the spiked sample. Uncertainties were obtained for each factor and the contribution for the total concentration uncertainty was 54.4% and 0.61%, 0.0072% and 0.018%, and 45.0%, respectively. The biggest contribution factor was concentration of the spike solution and the second was the isotopic ratio measured for the spiked sample solution. The mass flow rate of spike and atomic weights did not show much contribution. The calculated total uncertainty was $1.46ng{\cdot}g^{-1}$ for the standard SeMet ($126.30ng{\cdot}g^{-1}$). The experimental result was $127.09{\pm}1.46ng{\cdot}g^{-1}$ and the relative uncertainty was 1.20%.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.1-9
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• 2022

A design factor analysis was conducted to reduce the thrust reduction in the off-design, due to the driving of the aerospike pintle nozzle. The close (NPR 100) as well as the open (NPR 11) stroke were fixed, as under-expansion conditions. The pintle contour, pintle head radius (R), cowl angle (θ), and cowl exit length (L) were selected as design factors. The change in thrust was analyzed, using a verified numerical analysis technique. First, the pintle head radius and the length of the cowl exit had little influence on the thrust. The cowl angle changed the mass flow rate by affecting the effective nozzle throat area, and created a reverse pressure gradient at the cowl exit. As a result of applying the dual aerospike contour, it was confirmed that the thrust in the design-off increased by approximately 1.2%, compared to the reference case and by approximately 3.4% compared to the worst case.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.43-46
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• 2004

This work is experimental study about a nozzle part in the aerodynamic igniter using only compressible gas. In study, constructions of the aerodynamic igniter using a supersonic nozzle and an aerospike nozzle have been introduced, and experimental results(mainly max. heating temperature characteristics) have been presented. Using of the supersonic nozzle leads to faster and higher temperature in same mass flow, and the aerospike nozzle works in wide variable range of pressure.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.158-159
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• 2019

본 논문에서는 심층 신경망을 기반으로 하는 감정 인식을 위해 스파이크 특성을 추출하는 기술을 제안한다. 기존의 심층 신경망을 이용한 감정 인식 기술은 대부분 MFCC를 특성 백터를 사용한다. 그러나 프레임 단위의 연산인 MFCC는 높은 시간 해상도를 확보하기 어려워 시간적 특성의 영향을 받는 감정 인식에 한계가 있다. 이를 해결하기 위해 본 논문에서는 인간의 청각 필터를 모델링한 ERB에 따라 샘플 단위로 주파수의 특성을 나타내는 스파이크그램을 이용한 감정 인식 기술을 제안한다. 제안하는 방법이 감정 인식의 대표적 특성인 MFCC보다 높은 인식률을 제공하는 것을 확인하였다.

• Journal of Biomedical Engineering Research
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• v.38 no.6
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• pp.342-351
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• 2017

The neural decoding is a procedure that uses spike trains fired by neurons to estimate features of original stimulus. This is a fundamental step for understanding how neurons talk each other and, ultimately, how brains manage information. In this paper, the strategies of neural decoding are classified into three methodologies: rate decoding, temporal decoding, and population decoding, which are explained. Rate decoding is the firstly used and simplest decoding method in which the stimulus is reconstructed from the numbers of the spike at given time (e. g. spike rates). Since spike number is a discrete number, the spike rate itself is often not continuous and quantized, therefore if the stimulus is not static and simple, rate decoding may not provide good estimation for stimulus. Temporal decoding is the decoding method in which stimulus is reconstructed from the timing information when the spike fires. It can be useful even for rapidly changing stimulus, and our sensory system is believed to have temporal rather than rate decoding strategy. Since the use of large numbers of neurons is one of the operating principles of most nervous systems, population decoding has advantages such as reduction of uncertainty due to neuronal variability and the ability to represent a stimulus attributes simultaneously. Here, in this paper, three different decoding methods are introduced, how the information theory can be used in the neural decoding area is also given, and at the last machinelearning based algorithms for neural decoding are introduced.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.59-62
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• 2006

전산 신경과학은 신경 시스템을 생물물리학, 신경회로, 그리고 시스템 레벨 등 여러 가지 관점에서 크기와 구조를 모델링하여 신경 신호의 전달과 전달되는 정보의 내용을 이해하고자 하는 분야이다. 전산 신경과학은 기존의 생물학적인 신경과학 연구에 대한 보완적인 연구방법으로 이론적이고 계산적인 방법을 사용한다. 본 논문에서는 신경 세포에서 반응 인코딩에 해당되는 신호 발생율(firing rate)과 스파이크 통계(spike statistics)를 설명하고, 신경 세포에서 반응 디코딩에 해당되는 스파이크-트레인 디코딩(spike-train decoding)에 대하여 설명한다.

• The tire
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• s.31
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• pp.8-10
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• 1971

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.693-701
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• 2017

In this paper, we propose a new method for music genre classification using spikegram and deep neural network. The human auditory system encodes the input sound in the time and frequency domain in order to maximize the amount of sound information delivered to the brain using minimum energy and resource. Spikegram is a method of analyzing waveform based on the encoding function of auditory system. In the proposed method, we analyze the signal using spikegram and extract a feature vector composed of key information for the genre classification, which is to be used as the input to the neural network. We measure the performance of music genre classification using the GTZAN dataset consisting of 10 music genres, and confirm that the proposed method provides good performance using a low-dimensional feature vector, compared to the current state-of-the-art methods.

• Korean Journal of Ornithology
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• v.25 no.2
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• pp.112-116
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• 2018

Electrocution is one of the key components affecting the mortality of birds. Various electrocution-decreasing methods refer to two directions: safe perching with insulation versus perching restriction. In Yesan County, we have reintroduced 30 oriental storks (Ciconia boyciana) since 2015. Two female storks died due to electrocution while perching in a utility pole in 2016. To reduce such electrocution mortality in storks, a branch of Korea Electric Power Corporation partly installed insulators in 630 utility poles located in the major habitats of Yesan in 2016-2017. Simultaneously, we conducted an experiment to reduce the perching events using 8 captive storks and the two types of common utility poles along with/without the installation of bird-spikes and/or wires in Mar-Jun of 2017. Our results indicated the installation of additional wires alone exhibited a lack of reduction in perching, while those of bird-spikes or both significantly decreased their perching frequencies. Therefore, the present study highlights the installation of bird spikes on top of utility poles may elicit a better effect so that storks avoid perching in utility poles, presumably resulting in lowering potential electrocution in the wild.

• Environmental and Resource Economics Review
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• v.13 no.3
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• pp.417-440
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• 2004

For the behavior of the wholesale spot price, a regime switching model with time-varying transition probabilities was estimated using the data from the PJM (Pennsylvania-New Jersey-Maryland) market. By including the temperature as an explanatory variable in the transition probability equations, the threshold effect of changing regime is clearly enhanced. And hence the predictability of the price spikes was improved. This means that the model showed a very clear threshold effect, with a low probability of switching for low loads and low temperatures and a high probability for high loads and high temperatures. And temperature showed a clearer threshold effect than load does. This implies that weather-related contracts may help to hedge against the risk in the cost of buying electricity during a summer.