• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.351-356
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• 2017

The resistance of printed patterns for electrodes fabricated using printing technology should be minimized. This parameter depends on the pattern width and thickness; however, from the viewpoint of printability, the printed patterns should be printed at the designed width. The resistance of the printed patterns as well as printability is affected by various printing conditions. In this paper, the printing condition is optimized to minimize the resistance of electrodes printed by the roll-to-roll gravure method. This is done by considering the spread ratio of pattern width as a parameter of printability using design experiments. The drying temperature, dryer fan speed, and printing speed are selected as effective factors for the experiment objective. The optimized conditions are obtained and reproducibility test using these demonstrates that the optimized conditions can produce low-resistance electrodes for printability of the pattern width.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.35-43
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• 1999

The purpose of this study is to derive the optimal methodology estimating the changes of fluvial hydraulic characteristics due to semi-covering work of urban stream. First, after collecting the data of the daily maximum rainfall of Chungju gaging station, the frequency analysis was carried out with frequency factor method, which includes normal, two-parameter and three-parameter lognormal, Gumbel-Chow, pearson type III, log-pearson type III distribution, and the goodness of fit test was executed by $x^2$-test and Kormogorov-Smimov test. Using the SCS method, the effective rainfall was estimated and the peak flow was calculated by the area-routing method. The HEC-2 model was applied to calculate water surface profiles for steady, gradually varied flow at Kyohyun river system in Chungju city. The model was applied to floodplain and riverbed management to evaluate flood way encroachments and to delineate flood hazard by riverside roadway construction. The model also was used to evaluate effects on water surface profiles of river improvement and levees as well as the presence of bridges or other hydraulic structures in the floodplain.

• Steel and Composite Structures
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• v.28 no.5
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• pp.541-557
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• 2018

This paper presents the influence of carbon nanotubes (CNTs) waviness and aspect ratio on the vibrational behavior of functionally graded nanocomposite sandwich annular sector plates resting on two-parameter elastic foundations. The carbon nanotube-reinforced (CNTR) sandwich plate has smooth variation of CNT fraction along the thickness direction. The distributions of CNTs are considered functionally graded (FG) or uniform along the thickness and their mechanical properties are estimated by an extended rule of mixture. In this study, the classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. Effects of CNT distribution, volume fraction, aspect ratio and waviness, and also effects of Pasternak's elastic foundation coefficients, sandwich plate thickness, face sheets thickness and plate aspect ratio are investigated on the free vibration of the sandwich plates with wavy CNT-reinforced face sheets. The study is carried out based on three-dimensional theory of elasticity and in contrary to two-dimensional theories, such as classical, the first- and the higher-order shear deformation plate theories, this approach does not neglect transverse normal deformations. The sandwich annular sector plate is assumed to be simply supported in the radial edges while any arbitrary boundary conditions are applied to the other two circular edges including simply supported, clamped and free.

• Structural Engineering and Mechanics
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• v.61 no.2
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• pp.209-220
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• 2017

The purpose of this paper is to study the geometrically nonlinear free vibration of functionally graded nano/micro beams (FGNBs) based on the modified couple stress theory. For practical applications, some analytical expressions of nonlinear frequencies for FGNBs on a nonlinear Pasternak foundation are developed. Hamilton's principle is employed to obtain nonlinear governing differential equations in the context of both Euler-Bernoulli and Timoshenko beam theories for a comprehensive investigation. The modified continuum theory contains one material length scale parameter to capture the size effect. The variation of two-constituent material along the thickness is modeled using Reddy's power-law. Also, the Mori-Tanaka method as an accurate homogenization technique is implemented to estimate the effective material properties of the FGNBs. The results are presented for both hinged-hinged and clamped-clamped boundary conditions. The nonlinear partial differential equations are reduced to ordinary differential equations using Galerkin method and then the powerful method of homotopy analysis is utilized to obtain the semi-analytical solutions. Eventually, the presented analytical expressions are used to examine the influences of the length scale parameter, material gradient index, and elastic foundation on the nonlinear free vibration of FGNBs.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.27-38
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• 2012

This study is to analyse the hydrological behavior of agricultural reservoir using CAT (Catchment hydrologic cycle Assessment Tool). The CAT is a water cycle analysis model in order to quantitatively assess the characteristics of the short/long-term changes in watershed. It supports the effective design of water cycle improvement facilities by supplementing the strengths and weaknesses of existing conceptual parameter-based lumped hydrologic models and physical parameter-based distributed hydrologic models. The CAT especially supports the analysis of runoff processes in paddy fields and reservoirs. To evaluate the impact of agricultural reservoir operation and irrigation water supply on long-term rainfall-runoff process, the CAT was applied to Idong experimental catchment, operated for research on the rural catchment characteristics and accumulated long term data by hydrological observation equipments since 2000. From the results of the main control points, Idong, Yongdeok and Misan reservoirs, the daily water levels of those points are consistent well with observed water levels, and the Nash-Sutcliffe model efficiencies were 0.32~0.89 (2001~2007) and correlation coefficients were 0.73~0.98.

• Journal of Korea Multimedia Society
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• v.13 no.9
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• pp.1329-1336
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• 2010

Cellular Automata is a discrete dynamical system which natural phenomena may be specified completely in terms of local relation, can increase and decrease the difference of luminance locally according to transition rule by keeping the characteristic of target image. In this paper, we propose a noise reduction method by keeping the characteristic using transition rule of Cellular Automata, also we propose methods of effective transition rule, the selection of parameters, the selection of number of neighborhood pixels. For uniform distribution noise, Gaussian noise, impulse noise, we do an experiment on adaptive state using different mathematical operations and compare its results. It was confirmed that the proposed transition rule is based on fast convergence speed and has stabile results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1305-1314
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• 2011

Initial entry section has vulnerability which exposes plain text parameter in Mobile WIMAX environment which is the 4th generation technology. Each node message need to be encrypted to prevent the third party attack or message leakage. In this paper, we propose Mobile WIMAX initial entry section encryption using Elliptic Curve Cryptosystem. We have compared proposed model with existing model using OPNET simulator tool. He delay rate has increased little bit in initial entry section than before after the comparison, but it has shown more effective in average delay and throughput than encryption applied other existing model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.581-584
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• 2002

In this work, a CPW resonator was designed and fabricated to investigate the basic microwave properties, such as effective dielectric constant, of BST thin films. Their properties were used as basic data to simulate and design CPW tunable bandpass filter. We also report on gold/$Ba_{0.5}Sr_{0.5}TiO_3$(BST) ferroelectric thin film C-band tunable bandpass filters(BPFs) designed and fabricated on magnesium oxide substrates using CPW structure. The 2 pole filter was designed for a center frequency of 5.88 GHz with a bandwidth of 9 %. The BST based CPW filter offers a high sensitivity parameter as well as a low loss parameter. The tuning range for the bandpass filter with CPW structure was determined to be 170 MHz.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.206-209
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• 1999

Magnetic and superconducting properties in a series of intermetallic compounds Y$_{1-x}Tb_xNi_2B_2C$ were investigated by measuring the temperature dependent magnetization, M (T), and resitivity, ${\rho}$ (T). As Tb concentration, x, is increased, the superconducting transition temperature, T$_c$, decreases and eventually disappears in the vicinity of x = 0.5 while Neel temperature, T$_N$, appears abruptly near x = 0.4 and increases linearly. Of particular interest is the collision of superconductivity and antiferromagnetism around x = 0.4. The linear decrease of T$_c$ for dilute Tb concentration seems to follow the Abrikosov-Gor'kov behavior, while the decay of T$_c$ below T$_c$ is expected to originate from the effective magnetic field on the conduction electrons. The Ginzburg-Landau theory was phenomenologically constructed to explain this competition of superconducting order parameter and antiferromagnetic order parameter with the multi-band model.

• Journal of Radiation Protection and Research
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• v.44 no.4
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• pp.161-165
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• 2019

Background: Not only regulatory framework including radiation protection quantities and regulatory standards, but also methodology for regulatory compliance may be different in each country due to inherent philosophy for radiation protection. Materials and Methods: Based on the Korean regulatory models, off-site radiological dose resulting from the routine releases of gaseous radioactive effluents was calculated by applying the parameter values and assumptions recommended in the Korean and Japanese regulations. Results and Discussion: Effective dose for adult based on the Korean recommendation were 17.5 and 1.6 times higher than those of Japanese recommendation for ¹³¹I and ¹³³I, respectively, for the same atmosphere dispersion and ground deposition factors. Conclusion: It was due to different parameter values and assumptions recommended for the purpose of evaluating compliance with dose criteria for the radiation protection of the public in each country.