• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.11
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• pp.1038-1047
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• 2000

The objective of this study is to develop an optimized Artificial Neural Network(ANN) model to predict the descending time of room air temperature. For this, program for predicting room air temperature and ANN program using generalized delta rule were collected through simulation for predicting room air temperature. ANN was trained and the ANN model having the optimized values-learning rate, moment, bias, number of hidden layer, and number of neuron of hidden layer was presented.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.910-913
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• 2003

In order to enhance performance, stability, and brightness of inorganic blue-light emitting EL device, barrier layer structure and pulsed laser annealing(PLA) treatment were introduced. The barrier layer structure was utilized for improving brightness of the device and instead of thermal annealing, pulsed laser annealing process was used. From this study, optimum barrier layer thickness and number of pulsed laser irradiation are established.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1293-1297
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• 2016

Cholangiocarcinoma (CCA) is a serious problem in Thailand, particularly in the northeastern and northern regions. Database of population at risk are need required for monitoring, surveillance, home health care, and home visit. Therefore, this study aimed to develop a geographic information system (GIS) database and Google map of the population at risk of CCA in Mueang Yang district, Nakhon Ratchasima province, northeastern Thailand during June to October 2015. Populations at risk were screened using the Korat CCA verbal screening test (KCVST). Software included Microsoft Excel, ArcGIS, and Google Maps. The secondary data included the point of villages, sub-district boundaries, district boundaries, point of hospital in Mueang Yang district, used for created the spatial databese. The populations at risk for CCA and opisthorchiasis were used to create an arttribute database. Data were tranfered to WGS84 UTM ZONE 48. After the conversion, all of the data were imported into Google Earth using online web pages www.earthpoint.us. Some 222 from a 4,800 population at risk for CCA constituted a high risk group. Geo-visual display available at following www.google.com/maps/d/u/0/edit?mid=zPxtcHv_iDLo.kvPpxl5mAs90&hl=th. Geo-visual display 5 layers including: layer 1, village location and number of the population at risk for CCA; layer 2, sub-district health promotion hospital in Mueang Yang district and number of opisthorchiasis; layer 3, sub-district district and the number of population at risk for CCA; layer 4, district hospital and the number of population at risk for CCA and number of opisthorchiasis; and layer 5, district and the number of population at risk for CCA and number of opisthorchiasis. This GIS database and Google map production process is suitable for further monitoring, surveillance, and home health care for CCA sufferers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.35-42
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• 2011

In this study, ground calcium carbonate (GCC) was modified by Layer-by-Layer (LbL) multilayering with polyelectrolytes. Cationic polyacrylamide (C-PAM) and poly sodium 4-styrene sulfonate (PSS) were used as cationic and anionic polyelectrolytes to modify GCC. The characteristics of the modified GCC were examined in terms of zeta potential and particle size with the addition level of polyelectrolyte and layer number. The GCC could form an assembly of cationic and anionic polyelectrolytes through consecutive adsorption process. The zeta potential of the modified GCC moved toward the cationicity and reached the plateau with the increase of the addition level of C-PAM. With layering of anionic PSS, the GCC had the negative charge. The particle size was dependent on the zeta potential. It was also observed by optical microscope. As the PSS was in the presence of the outermost layer, the GCC showed the better dispersability. It indicated that the surface charge and particle size can be controlled by adjusting the addition level of polyelectrolyte and the layer number.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.371-372
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• 2015

EDISON 나노물리 사이트에 탑재된 태양전지 해석용 SW를 이용하여 최대전력(power)을 얻을 수 있는 태양전지 구조를 설계 및 파악해보았다. 최대전력을 얻기 위한 조건으로는 Number_of_Layer 즉, 층의 수(2~10가능)와 각 Layer의 물성(단결정, 비정질, 미세단결정)과 각 Layer의 두께, 각 Layer의 도핑밀도가 있다. 이러한 조건들을 조절하여 태양전지의 가장 높은 최대전력을 얻을 수 있는 구조를 SW를 통하여 설계하고, 분석하였다.

• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.315-322
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• 2018

Bamboo culm comprises internodes and nodes and is tapered from the bottom to the top. Anatomically, bamboo culm comprises vascular bundles and parenchymal base tissue. The gross anatomical structure of a transverse section of any culm internode is determined by the shape, size, arrangement, and number of vascular bundles. The purpose of this research was to examine the morphology of culm and the distribution and shape of vascular bundles in Ampel bamboo (Bambusa vulgaris). Bamboo culms were harvested from the base. Test samples were obtained from a central 2-cm long segment of each internode across the entire length of the culm. Results showed an uneven spread of vascular bundles in the internode cross-section. Transitioning from the outer to the inner layer of the internode, the number of vascular bundles per unit area decreased and their shape was variable. The size of vascular bundles in the middle layer of the internode was greater than that of those in the outer and inner layers. The shape of vascular bundles was circular in the outer layer, which gradually transformed into vertical oval toward the middle layer and horizontal oval toward the inner layer. Vascular bundles were of type III and IV in the bottom of the culm and type III in the middle to the top of the culm.

• Journal of Industrial Technology
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• v.41 no.1
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• pp.1-6
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• 2021

Fly ash and silica fume belong to industry by-products that can be used to produce concrete. This study shows the model of a neural network to evaluate the strength development of blended concrete containing fly ash and silica fume. The neural network model has four input parameters, such as fly ash replacement content, silica fume replacement content, water/binder ratio, and ages. Strength is the output variable of neural network. Based on the backpropagation algorithm, the values of elements in the hidden layer of neural network are determined. The number of neurons in the hidden layer is confirmed based on trial calculations. We find (1) neural network can give a reasonable evaluation of the strength development of composite concrete. Neural network can reflect the improvement of strength due to silica fume additions and can consider the reductions of strength as water/binder increases. (2) When the number of neurons in the hidden layer is five, the prediction results show more accuracy than four neurons in the hidden layer. Moreover, five neurons in the hidden layer can reproduce the strength crossover between fly ash concrete and plain concrete. Summarily, the neural network-based model is valuable for design sustainable composite concrete containing silica fume and fly ash.

• Bulletin of the Korean Chemical Society
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• v.19 no.5
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• pp.549-553
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• 1998

The structure and layer distribution of cadmium arachidate Langmuir-Blodgett film were analyzed by the small angle X-ray reflectivity measurements using synchrotron radiation. Y-to X type transition was ocurred during the 39th passage of deposition of cadmium arachidate. Based on the measurement of the consumed area of the monolayer, it was determined that about 27.5 layer was deposited. Using the synchrotron X-ray, the reflectivity profile of cadmium arachidate LB film over the wide range of grazing angle was obtained. The X-ray reflectivity profile was analyzed using the recursion formula. By fitting the location and dispersion of the subsidiary maxima between the Bragg peaks of the measured reflectivity profile with that of the calculated reflectivity profile, the average thickness and the distribution of layer thickness were evaluated. The genetic algorithm was adopted to the fitting of reflectivity profile to evaluate the optimum value of the number distribution of layer. Based on the morphology measurement with an atomic force microscopy (AFM), the domain structure and mean roughness of LB films were obtained. The mean roughness value calculated based on the number of layer distribution obtained from the measurement by AFM is consistent with that obtained from X-ray reflectivity analysis.

• Wind and Structures
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• v.31 no.3
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• pp.255-267
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• 2020

A systematic set of low-speed wind tunnel experiments was performed at Re = 6.5×10⁴ and 1.1×10⁵ to study the mean wind loading experienced by surface-mounted finite-height square prisms for different aspect ratios, incidence angles, and boundary layer thicknesses. The aspect ratio of the prism was varied from AR = 1 to 11 in small increments and the incidence angle was changed from α = 0° to 45° in increments of 1°. Two different boundary layer thicknesses were used: a thin boundary layer with δ/D = 0.8 and a thick boundary layer with δ/D = 2.0-2.2. The mean drag and lift coefficients were strong functions of AR, α, and δ/D, while the Strouhal number was mostly influenced by α. The critical incidence angle, at which the prism experiences minimum drag, maximum lift, and highest vortex shedding frequency, increased with AR, converged to a value of α_c = 18° ± 2° once AR was sufficiently high, and was relatively insensitive to changes in δ/D. A local maximum value of mean drag coefficient was identified for higher-AR prisms at low α. The overall behaviour of the force coefficients and Strouhal number with AR suggests the possibility of three flow regimes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.1
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• pp.96-107
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• 2001

An unsteady numerical simulation was performed to analyze flow structures behind a local suction/blowing in a flat-plate turbulent boundary layer. The local forcing was given to the boundary layer flow by means of sinusoidally oscillating jet. A version of the unsteady $\kappa$-$\xi$-f(sub)u model (Rhee and Sung 2000) was employed. The Reynolds number based on the momentum thickness was about Re(sub)$\theta$=1700. The forcing frequency was varied in the range 0.011$\leq$f(sup)+$\leq$0.044 with a fixed forcing amplitude A(sub)o=0.4. The predicted results were compared and validated with the experimental data. It was shown that the unsteady locally-forced boundary layer flow is predicted well by the $\kappa$-$\xi$-f(sub)u model. The effect of the pitch angle of local forcing on the reduction of skin friction was also examined.