• Tribology and Lubricants
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• v.33 no.4
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• pp.148-152
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• 2017

The feel of writing is important to customers when they buy smart devices with stylus such as smartphones and tablet computers. With an aim to reproduce the tactile sensibility of writing instruments when people write on the glass display using a stylus, this study focuses on the frequency characteristics of writing instruments that can describe the vibrations of writing instruments sliding over counter surfaces. In addition, this study includes the effect of various factors influencing the friction of writing instruments such as lubricant, nib material, and contact type. We perform sliding experiments with six types of writing instruments and a sheet of paper to understand the relation between the friction conditions of the nib and the frequency characteristics. As this research focuses on the tactile perception of human skin when people use a writing instrument, the analysis of frequency characteristics is performed in the perceptible frequency range of mechanoreceptors in the human skin. As a result, three types of frequency characteristics are identified. Low frequency peaks are observed for a metal nib with ink; high frequency peaks are observed for a nib without ink; and, middle frequency peaks with a wide range of distribution occurs for fabric nibs with ink. Therefore, to implement the proper feel of writing, at least three types of vibrations have to be made.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.1
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• pp.9-16
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• 1984

This paper describes the minimum cost expansion planning which is based on the economical aspect under the various conditions on the power system expansion planning. It presents not only linear cost characteristics analysis but also stepwise cost characteristics analysis which satisfies practical condition in the power system. The latter analysis must be handled by integer programming (IP), because the relation between the cost and the capacity has stepwise characteristics. In order to proceed the latter analysis, the solving procedure is illustrated in detais by using branch and bound method which includes the network flow theory and maximum flow-minimum cut theorem.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.703-704
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• 2007

Most of the transmission lines in Korea pass through a mountains. The forest fire occurred in around the transmission lines make an accident such as flashover and faults in the power transmission lines. In spite of that risk, there are no research on the flashover characteristics by fires in electric discharge engineering in our country. This paper was mentioned about the relation between the flame and flashover characteristics. We were carried out simple test by using artificial flame generator and rod-plane or conductor-plane gaps. And we were summarized test results.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.522-528
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• 1998

This paper presents a fundamental fractal characteristics of the growing crack that has an irregularity producing a zigzag crack contour. This irregularity is analysed by a fractal geometry in a box counting method that is a very simple technique. First the fractal dimensions and actual fractal extensive crack length are obtained. Also a fractal fracture energy relation with a fractal dimension is found so as to get fractal crack behaviors. Thus it can be shown that the fractal dimension has a possibility as a fracture parameter in a real crack growth length meaning.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.15-22
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• 2017

The microstructure observation of seed surface structure is needed for protocols of breaking dormancy of seeds with physical dormancy. The seeds of Rubus species are surrounded by a thick, hard endocarp; together, the seed and endocarp make up the stone. We evaluate stone characteristics of 18 species of Rubus through optical microscopic observation, and correlate different stone characteristics with endocarp thickness. As a result of stone size comparison, Rubus species were classified as big stones group including R. parvifolius and R. idaeus, small stones group including R. longisepalus var. longisepalus, R. corchorifolius and R. hirsutus, and middle stones group including rest of the species. The result of this study revealed that stone size and the endocarp thickness in Rubus species was various characteristics in each species. Furthermore stone size and stone weight were also well correlated endocarp thickness and result indicated that heavy stones had harder endocarp than lighter one. Thus from the result of this study it can be presumed that only one stone characteristic approach may be sufficient to estimate other characteristics in Rubus.

• Journal of Families and Better Life
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• v.28 no.3
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• pp.151-165
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• 2010

The purpose of this study was to examine teachers' practices of Eco Early Childhood Education (EECE) according to the characteristics and perceptions of daycare teachers, and the impacts of teachers' characteristics and perceptions on their EECE practices. The subjects in this study were 110 teachers who were worked at daycare centers in the Gyeongnam area of Korea. The teachers completed questionnaires concerning their perceptions and practices within the EECE. The collected data were analyzed by t-tests, one-way ANOVA, correlation coefficients, and regression. The results of this study were as follows: 1) The daycare teachers differed in their degree of EECE practices depending on their characteristics. 2) The daycare teachers were significantly different in their practices of EECE according to their perceptions. 3) The teachers' characteristics and perceptions of ECCE explained their practices of EECE. Particularly, teacher educational levels and the perceptions of ECCE by teachers were positively associated with their practices.

• Journal of ILASS-Korea
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• v.7 no.4
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• pp.32-41
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• 2002

The breakup characteristics of liquid sheets formed by like-doublet injector were investigated in the cold-flow and atmospheric ambient pressure condition. The sheet breakup wavelength, which induces the sheet to be broken into ligaments, as well as the sheet breakup length, which is important for the flame location, was measured using a stroboscopic light. The liquid ligaments are formed intermittently after the breakup of sheet, and the wavelength of ligaments has been believed to have a relation to the combustion instability of liquid rocket engine. Therefore, the wavelength of ligaments and the breakup length of ligaments into fine drops were also measured. Since these spray characteristics are affected by the flow characteristics of two liquid jets before they impinge on each other, we focused on the effects of orifice internal flow such as the cavitation phenomenon that occurs inside the sharp-edged orifice. From the experimental results, we found that the liquid jet turbulence delays the sheet breakup and makes shorter wavelengths for both sheets and ligaments. Since the turbulent strength of sharp-edged orifice is stronger than that of round-edged orifice, the shape of orifice entrance results in large differences in the spray characteristics. Using these results, we proposed empirical models on the spray characteristics of the like-doublet injector, and these models are believed to provide some useful and actual data for designing liquid rocket combustors.

• Korean Institute of Interior Design Journal
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• v.17 no.6
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• pp.92-101
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• 2008

In the current age, as the importance of image is increased, brand images are strengthened, and various ways of expressing space are suggested considering the life styles of consumers. Recently, flagship stores are attempting various ways of expressing interior deigns and the flow of life culture, which can maximize the characteristics of image in a large, complex space. Centering on this trend, this study is conducted to explore an objective standard for the stylistic image characteristics reflecting the formative expression trend; to investigate various expression methods of images that are suggested by flagship stores; and to suggest the indicators of design. Based on this background, the formative trend is classified into the expression trends of minimalism and deconstructionism. An image evaluation test was conducted on the selected brand cases by applying the classification, and the following results are obtained from a comparative analysis. In this study, a stylistic analysis of expression methods is suggested from the stylistic image characteristics of each brand as well as from the reliability and validity of the expression trend. It can be concluded that such stylistic image characteristics are important factors in relation with fashion and architecture, and they can be used for differentiating design expression methods.

• Korean Journal of Social Welfare
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• v.41
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• pp.7-42
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• 2000

Little empirical study has been conducted concerning social worker' empowerment that has very important function on clients' empowerment. Using the sample of 222 social workers selected from 92 community welfare centers, this study attempted to identify social workers' empowerment level and its predictors. This study used the empowerment scale developed by Leslie, Holzhalb, Holland (1998) that focuses on measurement of social workers's empowerment in social work agencies. Using confirmatory factor analysis, it was confirmed that the scale has three factors such as control of work environment, work relationships, and personal work orientation. This study showed that using 5 points scale, mean of social workers' empowerment is 3.67. In identifying predictors of the empowerment, this study used variables from the following aspects: organizational characteristics, job characteristics, and individual characteristics. Using regression analysis, it was found that variables related to job characteristics such as role ambiguities, role conflicts, and skill varieties are statistically very significant predictors of social workers' empowerment. Self-esteem in personal characteristics and participation in decision making and transformational leadership in organizational characteristics are also statistically significant predictors of social workers' empowerment. This study also revealed that self-control and self-esteem variables function as moderator in the relation with variables such as role ambiguities and role conflicts. Finally, this study discussed the direction of future research in social workers' empowerment and the areas that management efforts should be focused on for promoting social workers' empowerment.

• 전기의세계
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• v.17 no.3
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• pp.7-28
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• 1968

When a insulator plate is inserted to the discharge path of a space discharge gap in which the field strength is not uniform, the spark voltage under the atmospheric pressure between the electrodes decreases or rises according to the position of the insulating plate. Also it is reported that if a metallic barrier plate is inserted to the discharge path of the same space discharge gap, similar variations of spark voltage are found. Speaking briefly, mensioned above are the spark voltage characteristics when an insulator or metallic barrier is inserted to the space discharge gap. Also some experimental results, concerning to the surface creepage flash over characteristics at the case when an insulator barrier is inserted to the discharge path of a surface creepage discharge gap, were reported by Peek. But up to now there are no reports on surface flash over voltage characteristics at the case when a metallic barrier is inserted to the surface creepage gap. In this study the effects of a conducting metallic barrier inserted to the path of a surface creepage discharge gap on the flash over voltage characteristics are investigated theoretically and experimentally, and got some important results, clearing the effects of the position and width of a conducting barrier is inserted, the surface flash over voltage characteristics appear as an Inverse N or W Characteristics. Such theoretical or experimental results may have some relation not only with the effects of dry belt and snow on suspension insulators, but also with the effects of dirty zone or water drops on the surface creepage flash over voltage.