• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.385-392
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• 2016

Recently in the display industry, demands for high-luminance and resolution of display devices have been steadily increasing. Generally, micro linear patterns are applied to an optical film in order to improve its properties of light. However, these patterns are easily viewed to eyes and moire phenomenon can be occurred. Micro random patterns are proposed as a method to solve these problems, increasing light-luminance and light-diffusion. However, conventional pattern manufacturing technologies have long processing times and high costs making it difficult to apply to large area molds. In order to combat this issue, micro-random patterns are formed by using a roll to plate indentation method along with abrasive paper tools composed of AlSiO2, SiC, and diamond grains. Also, forming properties, such as size and fill-factor of random patterns, are analyzed depending on type, mesh of abrasive paper tools, and indentation forces.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.3
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• pp.77-85
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• 2002

A Research of binary random sequence generator that uses a linear shift register had been studied since the 1970s. These generators were used in stream cipher. In general, the binary random sequence generator consists of linear shift registers that generate sequences of maximum period and a nonlinear filter function or a nonlinear combination function to generate a sequence of high linear complexity. Therefore, To generate a sequence that have long period as well as high linear complexity becomes an important factor to estimate safety of stream cipher. Usually, the maximum period of the sequence generated by a linear feedback shift register with L resistors is less than or equal to $2^L$-1. In this paper, we propose new binary random sequence generator that consist of L registers and 2 sub-characteristic polynomials. According to an initial state vector, the least period of the sequence generated by the proposed generator is equal to or ions than it of the sequence created by the general linear feedback shift register, and its linear complexity is increased too.

• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.645-655
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• 2021

Performance-based reliability analysis is a practical approach to investigate the seismic performance and stochastic nonlinear response of structures considering a random process. This is significant due to the uncertainties involved in every aspect of the analysis. Therefore, the present study aims to evaluate the performance-based reliability within a stochastic finite element (FE) framework for reinforced concrete (RC) shear walls that are considered as one of the most essential elements of structures. To accomplish this purpose, deterministic FE analyses are conducted for both squat and slender shear walls to validate numerical models through experimental results. The presented numerical analysis is performed by using the ABAQUS FE program. Afterwards, a random-effects investigation is carried out to consider the influence of different random variables on the lateral load-top displacement behavior of RC members. Using these results and through utilizing the Monte-Carlo simulation method, stochastic nonlinear analyses are also performed to generate random FE models based on input parameters and their probabilistic distributions. In order to evaluate the reliability of RC walls, failure probabilities and corresponding reliability indices are calculated at life safety and collapse prevention levels of performance as suggested by FEMA 356. Moreover, based on reliability indices, capacity reduction factors are determined subjected to shear for all specimens that are designed according to the ACI 318 Building Code. Obtained results show that the lateral load and the compressive strength of concrete have the highest effects on load-displacement responses compared to those of other random variables. It is also found that the probability of shear failure for the squat wall is slightly lower than that for slender walls. This implies that 𝛽 values are higher in a non-ductile mode of failure. Besides, the reliability of both squat and slender shear walls does not change significantly in the case of varying capacity reduction factors.

• Journal of Korean Academy of Nursing
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• v.22 no.3
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• pp.316-324
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• 1992

The purpose of this study was to develop a ratio scale to measure job satisfaction of nurses and health workers in health centers. Of the 224 health centers in Korea, 105 were drawn as the sample using disproportion리 stratified random sampling. The data collection period was from May 1 to June 30, 1990 and 771 nurses and health workers working at 75 health centers participated. Subjects were instructed to rate, according to the level of satisfaction, from one to four points, 42 items revised from the tool made by Stamps et. al. (1978). The internal consistency reliability of the tool was measured by Cronbach $\alpha$ and the corrected item-total correlation coefficient. As a result of the item analysis, one item was excluded since the item had negative correlation with total items. As a result of factor analysis on the 41 items with varimax or above. Labeling and numbering of 6 factors were as follows ; factor 1 (8 items) ; Professional status of job. factor 2 (6 items) ; Interaction. factor 3 (8 items) ; Autonomy. factor 4 (8 items) ; Administration. factor 5 (7 items) ; Pay. factor 6 (4 items) ; Job(Task). Further studies are needed to identify the relationship between this tool and the effectiveness of the health center and more research is needed for generalization.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.528-532
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• 2013

In this study, an analytical model of micro-beam structure including thermoelastic damping with irregularly distributed masses is investigated. The significance of thermoelastic damping for micro-scale mechanical resonators is evaluated to design -with high quality factor(Q-factor). The beam model of this work is based on Euler-Bernoulli beam theory. In order to determine the natural frequency of the model, energy method is applied. Also, the thermoelatic damping effects are considered by using heat conduction equations, and the Q-factor can be determined. To derive the equation of motion, non-dimensionalization is employed for systematic analysis. Results of the model are verified, and present mode shapes and Q-factors for the micro-beam with thermoelastic damping including random point masses.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.221-224
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• 2004

A theoretical model has been studied to describe the sound radiation analysis for structure vibration noise of vehicle tires under the action of random moving line forces. When a tire is analyzed, it had been modeled as curved beams with distributed springs and dash pots that represent the radial , tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force, damping coefficient and stiffness of foundation will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number, wave-number ratio and stiffness factor. The experimental investigation for structure vibration noise of vehicle tire under the action of random moving line forces has been made. Based on the Spatial Transformation of Sound Field techniques, the sound power and sound radiation are measured. Results strongly suggest that operation condition in the tire material properties and design factors of the tire govern the sound power and sound radiation characteristics.

• Geomechanics and Engineering
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• v.23 no.1
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• pp.15-30
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• 2020

The probabilistic bearing capacity of a strip footing placed on the edge of a purely cohesive reinforced soil slope is computed by combining lower bound finite element limit analysis technique with random field method and Monte Carlo simulation technique. To simulate actual field condition, anisotropic random field model of undrained soil shear strength is generated by using the Cholesky-Decomposition method. With the inclusion of a single layer of reinforcement, dimensionless bearing capacity factor, N always increases in both deterministic and probabilistic analysis. As the coefficient of variation of the undrained soil shear strength increases, the mean N value in both unreinforced and reinforced slopes reduces for particular values of correlation length in horizontal and vertical directions. For smaller correlation lengths, the mean N value of unreinforced and reinforced slopes is always lower than the deterministic solutions. However, with the increment in the correlation lengths, this difference reduces and at a higher correlation length, both the deterministic and probabilistic mean values become almost equal. Providing reinforcement under footing subjected to eccentric load is found to be an efficient solution. However, both the deterministic and probabilistic bearing capacity for unreinforced and reinforced slopes reduces with the consideration of loading eccentricity.

• Journal of KSNVE
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• v.5 no.2
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• pp.169-181
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• 1995

A theoretical model has been studied to describe the sound radiation analysis for structural vibration noise control of tire under the action of random moving line forces. When a tire is analyzed, it has been modeled as a curved beam with distributed springs and dash-pots which represent the radial, tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y = 0 and to be axially infinite. The material of curved beam and elastic foundation are assumed to be lossless, and governed by the law of Bernoulli-Euler beam theory. The expression for sound power is integrated numerically and its results examined as a function of Mach number(M), wavenumber ratio(.gamma.) and stiffness factor(.PSI.). The experimental investigation for structural vibration noise of tire under the action of random moving line forces has been made. Based on the STSF(Spatial Transformation of Sound Field) techniques, the sound power and sound radiation are measured. The experimental results show that operating condition, material properties and design factors of the tire have a great effect on the sound power and sound radiation characteristics.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.1
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• pp.112-123
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• 2002

The purpose of this study was to establish the strategy for Internet fashion homepage advertising that attracts consumers attention and discloses clothing brand to consumers continually. In this paper, the following subjects were set up: (a) to classify the structure and evaluation factors of the fashion homepage advertising, (b) to analyze the effect of demographic variables and clothing involvement of consumer on fashion homepage advertising structures and evaluation factors. A random sample of 553 people in the age group 16-34s living in Seoul and Kyungki region during March 2000 was selected from Internet users. SPSS package was used for data analysis. Frequency, Percentage, Factor analysis, ANOVA, Duncan test and regression analysis were applied. The results of this research were as follows: First, in the process of classifying the dimension of the fashion homepage advertising, homepage advertising structure was composed of 5 factors: interactive, amusing factor, professional information, fashion information and useful information. And homepage advertising evaluating factors were interesting, information and irritation. Second, it was found that clothing involvement influenced fashion homepage advertising. High involvement group preferred the fashion information factor of the homepage advertising structure and low involvement group was useful information factor of the homepage advertising structure. Both high and low involvement groups preferred interesting factor of the homepage advertising evaluation. Third, demographic variables also influenced fashion homepage advertising Females manifested greater interests in informative factor of homepage advertising than males. Findings from this study provide an insight into fashion homepage advertising strategy related to consumers clothing behavior.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.850-854
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• 2009

Approximate analysis for a building installed with a friction damper is revisited to get insight of its dynamic behavior. Energy balance equation is used to have a closed analytical form solution of dynamic magnification factor (DMF) for the building with combined viscous and friction damping. It is found out that DMF is dependent on friction force ratio and resonance frequency. Linear transfer function from input external force to output building displacement is obtained by simplifying DMF equation. Root mean square of building displacement is derived under earthquake-like random excitation. Finally, design of friction damper is proposed by processing target control ratio, damping ratio factor, and friction force in sequence.