• Wind and Structures
• /
• 제2권2호
• /
• pp.105-117
• /
• 1999

The various spectral density functions of wind are applied in the wind process simulation by the spectral representation method. In view of the spectral density functions, the characteristics of the simulated processes are compared. The ensemble spectral density functions constructed from the simulated sample processes are revealed to have the similarity not only in global shape but also in the maximum values with the target spectral density functions with a high accuracy. For the correlation structure to be satisfied in the circumferential direction on the cooling tower shell, a new formula is suggested based on the mathematical expression representing the circumferential distribution of the wind pressure on the cooling tower shell. The simulated wind processes are applied in the dynamic analysis of cooling tower shell in the time domain and the fluctuating stochastic behavior of the cooling tower shell is investigated.

• Journal of Microbiology and Biotechnology
• /
• 제5권3호
• /
• pp.163-166
• /
• 1995

Chemical modification of gelatin-based macroporous microcanier beads was achieved by increasing the charge density through incorporation of (diethylamino)ethylchloride-hydrochloride (DEAE:CI-HCI) or lysine, and this significantly improved the attachment and growth of HepG2 cells. When microcarriers were modified by the addition of 2% lysine, positive charge density was 0.95 meq/g-caniers. In case of modification of microcarriers with DEAE:CI-HCI, positive charge density was 0.6 meq/g-caniers. An increase in charge density of the microcaniers to improve cell attachment has facilitated the growth of the cells on macroporous gelatin microcaniers. Also, final HepG2 cell concentration cultivated on modified beads with DEAE:CI-HCI was increased up to $10^7$ cells/ml. This was 2-3 times higher than that obtained with unmodified macroporous gelatin microcarriers.

• Smart Structures and Systems
• /
• 제15권3호
• /
• pp.735-749
• /
• 2015

The major difficulty of using Bayesian probabilistic inference for system identification is to obtain the posterior probability density of parameters conditioned by the measured response. The posterior density of structural parameters indicates how plausible each model is when considering the uncertainty of prediction errors. The Markov chain Monte Carlo (MCMC) method is a widespread medium for posterior inference but its convergence is often slow. The differential evolution adaptive Metropolis-Hasting (DREAM) algorithm boasts a population-based mechanism, which nms multiple different Markov chains simultaneously, and a global optimum exploration ability. This paper proposes an improved differential evolution adaptive Metropolis-Hasting algorithm (IDREAM) strategy to estimate the posterior density of structural parameters. The main benefit of IDREAM is its efficient MCMC simulation through its use of the adaptive Metropolis (AM) method with a mutation strategy for ensuring quick convergence and robust solutions. Its effectiveness was demonstrated in simulations on identifying the structural parameters with limited output data and noise polluted measurements.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1201-1206
• /
• 2004

This paper deals with the numerical analysis of natural convection flow induced by the density inversion effect of water inside horizontal pipe. The numerical method is based on SIMPLE/PWIM in general coordinate for its wide applicabilities. The numerical tool was validated through the comparison with the previous results concerning the density inversion effect of water It is shown that the developed numerical tool could predict the flow pattern and the heat transfer phenomena qualitatively And it is also found that the density inversion effect of water has significant effects on the flow pattern.

• Journal of Information Processing Systems
• /
• 제16권1호
• /
• pp.145-154
• /
• 2020

Maximum likelihood (ML) is the best estimator asymptotically as the number of training samples approaches infinity. This paper deduces an adaptive algorithm for blind signal processing problem based on gradient optimization criterion. A parametric density model is introduced through a parameterized generalized distribution family in ML framework. After specifying a limited number of parameters, the density of specific original signal can be approximated automatically by the constructed density function. Consequently, signal separation can be conducted without any prior information about the probability density of the desired original signal. Simulations on classical biomedical signals confirm the performance of the deduced technique.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 춘계학술대회 논문집
• /
• pp.449-453
• /
• 2005

Electrochemical systems find widespread technical application. Industrial electrolytic process include electroplating, electroforming, and electropolishing. Electroforming and electroplating is widely used in the manufacture of metal parts. This paper based on the basic equations of electrics and electrochemical kinetics, was employed for a theoretical explanation of the current density distribution on electroforming process. We calculated current density distribution and potential distribution on cathode. Also, calculated current density distribution of vertical direction. It was shown that current density is related with distance of between anode and cathode and mass transfer process. And make an experiment on its relation and electroformed thickness. It shows that it is useful method using FEM with multi-physics to estimate electroformed thickness.

• Journal of Electrochemical Science and Technology
• /
• 제12권1호
• /
• pp.38-57
• /
• 2021

The different weight ratios of Pd to Pt, i.e., 16:4, 10:10, 4:16 in Pd-Pt/C and Pd (20 wt. %) /C electrocatalysts with low metal loading were synthesized for glycerol electrooxidation in an air breathing microfluidic fuel cell (MFC). The cell performance on Pd-Pt (16:4)/C anode electrocatalyst was found best among all the electrocatalysts tested. The single cell when tested at a temperature of 35℃ using Pd-Pt (16:4)/C, showed maximum open circuit voltage (OCV) of 0.70 V and maximum power density of 2.77 mW/㎠ at a current density of 7.71 mA/㎠. The power density increased 1.45 times when cell temperature was raised from 35℃ to 75℃. The maximum OCV of 0.78 V and the maximum power density of 4.03 mW/㎠ at a current density of 10.47 mA/㎠ were observed at the temperature of 75℃. The results of CV substantiate the single cell performance for various operating parameters.

• 한국멀티미디어학회논문지
• /
• 제25권4호
• /
• pp.620-627
• /
• 2022

This study analyzed the shot pattern through the tempo of segmented shot duration and studied the relationship with the unique emotion of the story. The structure of the story was classified into 3 chapters, 17 sequences, 83 scenes, 287 beats, and 1636 shots. Shot density is a method of visualizing tension in visual storytelling, and since it is a result obtained by mathematically calculating the density of divided shots, it can be helpful in designing tension delivered to the audience. Nine shot density patterns were extracted. The ascending(+) type was classified as A, B, C, D, 4, the descending(-) type, E, F, G, H, 4, and the maintenance(/) type, I, 1 type. Based on the spatiality of the 17 stages of Campbell's heroic narrative and McGee's story structure, the narrative level of the tree structure was proposed, and the symbolic meaning of the shot rhythm in the practical aspect of the story function was proposed to present a systematic methodology in the direction of production.

• Carbon letters
• /
• 제6권4호
• /
• pp.234-242
• /
• 2005

Bending and tensile properties of 2D cross-ply C/C composites with processing heat treatment temperature (HTT) are evaluated. C/C composites used are made from two types of PAN based T700 and M40 carbon fibers with phenolic resin as carbon matrix precursor. Both the types of composites are heat treated at different temperatures (ranging from 750 to $2800^{\circ}C$) and characterized for bending and tensile properties. It is observed that, real density and open porosity increases with HTT, however, bulk density does show remarkable change. The real density and open porosity are higher in case T-700 carbon fiber composites at $2800^{\circ}C$, even though the density of M40 carbon fiber is higher. Bending strength is considerably greater than tensile strength through out the processing HTT due to the different mode of fracture. The bending and tensile strength decreases in both composites on $1000^{\circ}C$ which attributed to decrease in bulk density, thereafter with increase in HTT, bending and tensile strength increases. The maximum strength is in T700 fiber based composites at HTT $1500^{\circ}C$ and in M40 fiber based composites at HTT $2500^{\circ}C$. After attending the maximum value of strength in both types of composite at deflection HTT, after that strength decreases continuously. Decrease in strength is due to the degradation of fiber properties and in-situ fiber damages in the composite. The maximum carbon fiber strength realization in C/C composites is possible at a temperature that is same of fiber HTT. It has been found first time that the bending strength more or less 1.55 times higher in T700 fiber composites and in M40 fiber composites bending strength is 1.2 times higher than that of tensile strength of C/C composites.

• 한국컴퓨터정보학회논문지
• /
• 제15권12호
• /
• pp.37-45
• /
• 2010

본 논문에서는 밝기 값의 대비도가 매우 낮음으로 인해 발생하는 화질의 저하를 개선하는 방법으로 히스토그램 분포율에 따라서 스트레칭 적용범위를 적절하게 지정하고 이를 적용하는 기법을 제안한다. 제시한 방법은 효과적인 대비향상을 위해 하나의 히스토그램을 밀도가 큰 영역과 밀도가 낮은 영역으로 구분하여 각각의 비율에 따른 범위 안에서 스트레칭 적용 범위를 결정하는 기법을 사용한다. 스트레칭의 범위는 히스토그램의 분활 및 밀집되어 있는 정도의 비율에 따라 가변적으로 결정된다. 스트레칭 적용범위가 가변적으로 결정된다면 히스토그램상의 밀도가 높은 지역은 그만큼 명암대비가 커지도록 넓게 스트레칭하고 반대로 밀도가 낮은 지역은 그만큼 좁은 간격으로 스트레칭하여 명암대비 영상에서의 과도하게 처리되는 문제점을 해결하였다. 제안한 방법의 성능 평가를 위해 전역적 및 지역적으로 명암대비가 어려운 영상들을 모아 실험하였으며 기존의 스트레칭 알고리즘과 그 밖의 명암 대비개선 기법들을 함께 비교하여 매우 우수한 성능을 보임을 입증하였다.