• 한국해양공학회지
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• 제22권2호
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• pp.91-98
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• 2008

In order to establish a design guide for the bottom plate structure of a 4.3 ton aluminum planning boat, the feasibilities of bottom plate scantling of the ship are investigated based on the results of structural strength analysis and a simple equation and evaluation system are developed for initial structural design purposes. This study consists of 5 steps: First, the background, necessity, and purpose of this study are explained briefly, Second, the principal dimensions of this ship, the position of the considered bottom plate members and material characteristics are introduced. Third, the equivalent design pressure concept is introduced and evaluated based on experience and experimental data. Fourth, the strength of bottom plate members are examined using elasto-plastic nonlinear structural analysis, and response levels and several boundary conditions are reviewed based on the analysis results. Finally, in order to suggest design guides in respect to the ship's structural design, a simple design equation and evaluation system for bottom plate members are suggested for boats in the 4.3 ton aluminumboat range through the introduction of safety factorsbased on the ultimate design pressure concept.

• 한국보육지원학회지
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• 제12권2호
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• pp.239-262
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• 2016

This study investigates how naturally occurring parent groups form by using Schaefer's two axes of affection-rejection and autonomy-control, it also aims to verify whether there is a significant difference in the parent groups' emotional expressiveness and children's peer competence. A total of 201 kindergarten children between the age of 3 to 5 and their parents were given a questionnaire in order to investigate parenting attitudes and emotional expression. And children's teachers measured their peer competence. SPSS 18.0 was used and clustering analysis was conducted according to different parenting attitudes. The first fathers' group was named the lacking-affection group, the second was the democratic-reception group, the third was the ignorance group and the last was the rejection group. For mothers' groups, the first was named the rejection group, the second was the autonomous-control group and the third was the reception-respect group. Parents' emotional expressiveness of each group had a considerable difference while there was no significant difference between children's peer competence. This study was dedicated in deriving meaningful implications on the role of parents by investing the differences between each naturally occurring cluster.

• 한국음향학회지
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• 제31권4호
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• pp.225-234
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• 2012

The anechoic chamber is essential tool to measure the various acoustic parameters with high precision. The chamber provides the climate controlled indoor environments but requires the dedicated room at a great cost in order to isolate and absorb sound field. Provided the purpose of the chamber is specific to the experiments of sound localization, the performance requirements excluding free field can be alleviated for cost effective solution. This paper designs low cost and profile anechoic chamber based on acoustic pyramids and evaluates the performance specified by the Annex of ISO 3745. Data analysis is employed to measure the free and hemi-free field performance over five straight paths for working areas and four paths for non-working areas. The identical two measurement campaigns were conducted for free and hemi-free field chamber which is easily interchangeable by simple labor in this chamber design. In the working area with conventional speaker, the results of these analyses demonstrate that lab-designed anechoic chamber is in conformance with ISO 3745 for 250 Hz - 16 kHz one-third octave band at free field chamber and for 1 kHz - 16 kHz one-third octave band at hemi-free field chamber.

• 대한가정학회지
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• 제50권4호
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• pp.37-50
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• 2012

This research was conducted for the analysis the middle-old aged empty nest households' debt holdings and their financial status(emergency fund index, liquidity index, debt burden index) considering the level of income and assets. In order to accomplish this study, we made use of the KReIS third beta-version data. The results of the analysis were as follows. First, in all income asset groups there were more non-debts holding houses compared to debt holding houses. Moreover in debts holding houses, compared to other groups high income high assets groups were more. Second, the households that possessed more assets, had more debts. Third, the financial status of the households holding debts were more vulnerable compared to households that had no debts. Moreover, all income asset groups' emergency fund index were low. Households having no debts possessed low real assets and so the liquidity index was higher in holding debts households. In holding debts households, debt burden index was high. And especially these houses suffered from high debt burden when their income and asset were low.

• 대한전기학회논문지:전력기술부문A
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• 제51권10호
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• pp.495-501
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• 2002

A difference based current transformer (CT) saturation detection algorithm uses the third difference of a secondary current to detect the instants of the beginning/end of saturation. The third difference of a secondary current contains high frequency components when a CT is saturated. Thus, an effect of an anti-aliasing lowpass filter implemented in digital protection relays on the detection algorithm should be studied. This paper describes performance analysis of a lowpass filter on the CT saturation detection algorithm. The cutoff frequency of the lowpass filter is normally set to be half of a sampling frequency. In this Paper, two sampling frequencies of 3,840 (Hz) corresponding to 64 sample/cycle (s/c) and 1,920 (Hz) corresponding to 32 (s/c) are studied; the cutoff frequencies of the lowpass filters are set to be 1,920 (Hz), 960 (Hz) and 960(Hz), 480(Hz), respectively. And the proposed algorithm is verified by experiment. A 2nd order Butterworth filter is designed as a lowpass filter. The test results and experiment results clearly indicate that the saturation detection algorithm successfully detects the instants of the beginning/end of saturation even though a secondary current is filtered by the designed lowpass filters.

• Journal of Korean Biological Nursing Science
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• 제19권2호
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• pp.69-75
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• 2017

Purpose: The purpose of this study was to identify the factors that affect nursing students' performance on standard precaution of infection control. Methods: For the analysis of the study results, mistakes and percentages, descriptive statistics, Pearson's coefficient, and multiple regression analysis were performed. Results: Among the participants, 76.5% received hospital infection education, and 72.5% experienced an exposure to blood or body fluid, and the most of the exposures were occurred during the first semester of the third year. The knowledge score was $20.08{\pm}2.09$, the awareness score was $4.63{\pm}.41$, and the performance score was $4.34{\pm}.55$. In the relationship between the standard precautions knowledge, awareness, and performance, the awareness and the performance were in positive correlations, while the factors that affected the performance level of the standard precautions were awareness and the school year (third year), which had 37.0% of the total exposures. Conclusion: In order to increase the performance level of the standard precautions among the nursing department students, after identifying the differences between school years and demands of the students, it is necessary to provide continuous and regular education of standard precautions.

• 한국환경복원기술학회지
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• 제19권6호
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• pp.31-40
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• 2016

This study identifies the basic personality types of subjects who use the healing garden and investigates their plants-preference. The purpose of the study is to provide a basic information about planting plan, considered as a main parts of healing garden. Survey results are stated as follows: First, the order of preference of instinct type tree is Prunus yedoensis, zelkova serrata, Phyllostachys Bambusoides. On the other hands, the order of preference of feeling and thinking type is Prunus yedoensis, zelkova serrata, Metasequoia glyptostroboides. Second, the order of preference of instinct type of flowers is Rosa hybrida, Hibiscus syriacus, Forsythia koreana. However, the preference of emotional type is the order of Rosa hybrida, cosmos bipinnatus, Helianthus annuus and the preference of accident type is the order of Rosa hybrida, Hibiscus syriacus, Helianthus annuus. Third, for the color preferences, instinct type prefer yellow color, feeling type and thinking type prefer red color. Lastly, when people view plants, most personality types are interested in flower firstly, and secondly type of tree and scent. In other words, we can assume that people are interested in the flowers, most noticeable in plants. This study will enhance the effectiveness of the healing garden by providing relevant information regarding healing garden planting plan. Future research should consider to widen the range of target of investigation in order to perform additional comparison analysis.

• 한국강구조학회 논문집
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• 제11권1호통권38호
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• pp.55-67
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• 1999

복합재료로 구성된 복합적층판 및 쉘과 같은 구조물은 탄성계수와 전단탄성 계수의 비가 매우 커서 전단변형의 영향이 크므로 정확한 해를 얻기 위하여 해석 및 설계에서 필수적으로 전단변형을 고려해야 하며, 고차의 전단변형이론에 의한 해석은 더욱 정확한 해를 얻을 수 있다. 본 연구는 단순지지 경계조건을 갖는 복합적층판 및 쉘에 대하여 3차 전단변형 이론을 적용하여 플라이 각도, 층의 수에 따른 복합적층판 및 쉘의 휨, 진동, 좌굴 특성을 연구한다.

• 대한안전경영과학회지
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• 제18권1호
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• pp.75-82
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• 2016

According to the statistics, occupational fatal injuries by the fork lifts were about 30 per year in whole industrial. Fork lifts are widely used in various parts of industries to improve the efficiency of the work. In this study, the current regulations to be adequate in industrial site have to be renew in order to prevent the fatal injuries by the fork lifts. Fatal injury analysis were conducted with several accident cases by the fork lifts. For each accident, the causes of the injuries were examined and proper safety measures were proposed. In this study, the fork lift showed a high fatality rate in industrial accidents and no detailed cause analysis of fatal accidents was conducted in terms of unsafe acts or conditions. First, fork lifts were the highest of the machines caused the accidents. In order to prevent fatal injuries by the fork lifts, the tarket was manufacturing industry. Second, the order of the cause of cognitive engineering agenda in the manufacture industrial was visibility, responsibility and affordance, and revision of acts was proposed. Third, there was not a lots of different points of human error between occurrence types and business sizes. Forth, number of fatalities by the attacker was more than by the inducer.

• Steel and Composite Structures
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• 제27권3호
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• pp.273-283
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• 2018

Nonlinear low velocity impact response of sandwich beam with laminated composite face sheets and soft core is studied based on Extended High Order Sandwich Panel Theory (EHSAPT). The face sheets follow the Third order shear deformation beam theory (TSDT) that has hitherto not reported in conventional EHSAPT. Besides, the two dimensional elasticity is used for the core. The nonlinear Von Karman type relations for strains of face sheets and the core are adopted. Contact force between the impactor and the beam is obtained using the modified Hertz law. The field equations are derived via the Ritz based applied to the total energy of the system. The solution is obtained in the time domain by implementing the well-known Runge-Kutta method. The effects of boundary conditions, core-to-face sheet thickness ratio, initial velocity of the impactor, the impactor mass and position of the impactor are studied in detail. It is found that each of these parameters have significant effect on the impact characteristics which should be considered. Finally, some low velocity impact tests have been carried out by Drop Hammer Testing Machine. The contact force histories predicted by EHSAPT are in good agreement with that obtained by experimental results.