• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.895-900
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• 2016

Remaining useful life (RUL) estimation of the Li-ion battery has gained great interest because it is necessary for quality assurance, operation planning, and determination of the exchange period. This paper presents the RUL estimation of an Li-ion battery for an energy storage system using exponential function for the degradation model and Markov Chain Monte Carlo (MCMC) approach for parameter estimation. The MCMC approach is dependent upon information such as model initial parameters and input setting parameters which highly affect the estimation result. To overcome this difficulty, this paper offers a guideline for model initial parameters based on the regression result, and MCMC input parameters derived by comparisons with a thorough search of theoretical results.

• The Journal of the Acoustical Society of Korea
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• v.38 no.6
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• pp.716-723
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• 2019

Fingerprint matching accuracy is essential in deploying a music search service. This paper deals with a method to improve fingerprint matching accuracy by utilizing an auxiliary information which is called power weight. Power weight is an expected robustness of each hash bit. While the previous power mask binarizes the expected robustness into strong and weak bits, the proposed method utilizes a real-valued function of the expected robustness as weights for fingerprint matching. As a countermeasure to the increased storage cost, we propose a compression method for the power weight which has strong temporal correlation. Experiments on the publicly-available music datasets confirmed that the proposed power weight is effective in improving fingerprint matching performance.

• Structural Engineering and Mechanics
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• v.11 no.1
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• pp.71-87
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• 2001

A frequency domain response analysis is presented for building frames passively controlled by viscoelastic dampers, under harmonic ground excitation. Three different models are used to represent the linear dynamic force-deformation characteristics of viscoelastic dampers namely, Kelvin model, Linear hysteretic model and Maxwell model. The frequency domain solution is obtained by (i) an iterative pseudo-force method, which uses undamped mode shapes and frequencies of the system, (ii) an approximate modal strain energy method, which uses an equivalent modal damping of the system in each mode of vibration, and (iii) an exact method which uses complex frequency response function of the system. The responses obtained by three different methods are compared for different combinations of viscoelastic dampers giving rise to both classically and non-classically damped cases. In addition, the effect of the modelling of viscoelastic dampers on the response is investigated for a certain frequency range of interest. The results of the study are useful in appropriate modelling of viscoelastic dampers and in understanding the implication of using modal analysis procedure for building frames which are passively controlled by viscoelastic dampers against base excitation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.859-866
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• 1994

It is difficult to make an exact estimate of the peak discharge or the runoff depth of flood and establish the proper measure for the flood protection since the water stage or discharge has been nearly measured at most medium or small river basins. The objective of this study is to estimate parameters of the discrete, linear, input-output model for medium or small river basin. The On-Cheon River basin in Pusan was selected for the study area. The runoff data used in the study has been observed since June 1993, and the effective rainfall was determined using the storage function method. The parameter sets of the discrete, linear, input-output model were estimated using the least squares method and the correlation function method, respectively. The calculated hydrographs by the discrete, linear, input-output model regenerated the observed outflow hydrographs well, and also the simulated flood hydrograph was comparable to the observed one. Therefore, it is believed that the discrete, linear, input-output model is simpler than other runoff analysis methods, and can be applied to a medium or small river basin.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.4
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• pp.286-290
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• 2005

We consider the poisson equation where the functions involved are periodic including the solution function. Let $R=[0,1]{\times}[0,l]{\times}[0,1]$ be the region of interest and let $\phi$(x,y,z) be an arbitrary periodic function defined in the region R such that $\phi$(x,y,z) satisfies $\phi$(x+1, y, z)=$\phi$(x, y+1, z)=$\phi$(x, y, z+1)=$\phi$(x,y,z) for all x,y,z. We describe a very simple method for solving the equation ${\nabla}^2u(x, y, z)$ = $\phi$(x, y, z) based on the cubic spline interpolation of u(x, y, z); using the requirement that each interval [0,1] is a multiple of the period in the corresponding coordinates, the Laplacian operator applied to the cubic spline interpolation of u(x, y, z) can be replaced by a square matrix. The solution can then be computed simply by multiplying $\phi$(x, y, z) by the inverse of this matrix. A description on how the storage of nearly a Giga byte for $20{\times}20{\times}20$ nodes, equivalent to a $8000{\times}8000$ matrix is handled by using the fuzzy rule table method and a description on how the shape preserving property of the Laplacian operator will be affected by this approximation are included.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.75-83
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• 2003

Diode laser absorption system is advantageous of their non-invasive nature, fast response time, high sensitivity and real-time measurement capability. Furthermore, recent advances in room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications are enabling combustion diagnostics system based on diode laser absorption spectroscopy. So, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor system are now appearing for a variety of applications. The objective of this research is to take advantage of distributed feed-back diode laser and develope new gas sensing system. It experimentally found out that the wavelength, power characteristics as a function of injection current and temperature. In addition to direct absorption and wavelength modulation spectroscopy have been demonstrated in these experiments and have a bright prospect to this diode laser system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.86-89
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• 1995

In this pacer, The effect of the impedances in SNOSEFT s memory devices has been developed. The effect of source and drain impedances are measuring using the method of the field effect bias resistance in the inner resistance regions of the device structure and external bias resistance. The effect of impedance by source and drain resistance shows according to increasing to the storage of memory charges, shows according to a function of decreasing to the gate voltages, shows the delay of threshold voltages, The delay time of low conductance state and high conductance state by the impedance effect shows 3 [${\mu}$sec] and 1[${\mu}$sec] respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.90-94
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• 2005

본 연구의 목적은 현 국내 홍수 예경보시스템에 사용되고 있는 저류함수모형의 매개변수 변화에 따른 유량해석의 불확실성을 평가하는데 있다. 적용 대상지점으로는 개진을 출구로 하는 낙동강 회천유역($747.5km^2$)이며 비교적 양호한 수문자료를 가지고 있는 단일 호우사상을 선정하였다. 불확실성 평가에 사용된 매개변수는 관측수문곡선을 비교적 정확하게 모의하는 경험적인 값을 기준으로 Monte Carlo 기법을 이용하여 각각의 매개변수(K, P, $T_{1},\;f_{l},\;R_{sa}$)에 대한 정규분포를 가지는 100개의 난수를 발생시켜 저류함수 모형으로 모의되는 유량 앙상블을 평가하였다. 최적화된 매개변수를 이용하여 유량해석을 실시한 결과, 각각의 매개변수가 유출해석에 미치는 영향을 파악할 수 있었으며, 그 중 저류상수 K와 포화누가우량 Rsa가 불확실성이 제일 큰 매개변수로 나타났고, 이들의 혼합 앙상블 유출결과도 매우 큰 불확실성을 내포하는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1975-1979
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• 2006

본 연구의 목적은 국내 홍수예경보의 일부로 사용되고 있는 유역 및 하도 저류함수모형을 칼만필터를 이용하여 실시간 홍수추적에 적합한 추계동력학적 저류함수모형으로 개발하여 그 적용을 평가하는데 있다. 기존의 저류함수모형과 본 연구의 추계동력학적 모형의 적용을 위해 낙동강 유역내의 감천 유역 중 김천 수위지점 상류유역을 선정하였다. 유출분석을 위해 김천 수위지점 상류유역을 3개의 소유역으로 구분하였고, 2002년 8월에서 2003년 8월 사이에 발생한 3개의 주요 호우사상을 선정하였다. 면적강우는 감천유역 내외에 존재하는 9개 강우관측소로부터 Thiessen 방법을 이용하여 계산하였고, 모형에 사용된 매개변수는 호우사상별로 기존의 저류함수모형의 관측치를 잘 모의하는 값을 사용하였다. 두 모형의 유출해석 결과를 도식적 및 통계적으로 분석한 결과 본 연구에서 개발된 추계동력학적 유역 및 하도 저류함수모형이 모형 효율성 계수는 $0.94{\sim}0.96$, 유출용적 및 첨두유량 오차는 10% 내외를 보이며, 기존의 모형보다 정확한 유량예측이 가능한 것으로 나타났다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.311-317
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• 1998

Recently irrigation reservoir has been developed to perform multipurpose function. To get a maximum effect it requires to establish optimal management system for irrigation reservoir in drought and flood season. Especially we dealt with optimal flood control system for irrigation reservoir in this study. This system consists of real-time rainfall data via online system, real-time flood forecasted by SCS method in hourly basis, storage volume by water balance equation, optimal releasing discharge from the gate, the water level in right downstream, and calculation of innundated area, depth, and time using GIS, and amount of flood damages. If we consider the relation of these sub module reasonably, we can reach the optimal flood control to minimize flood damage