• 전자공학회논문지A
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• 제31A권3호
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• pp.46-52
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• 1994

We investigated theoretically the current-voltage characteristics of resonant tunneling diodes with a single quantum well structure. using a self-consistent method. This method is a numerical analysis which is able to include the effects of the undoped spacer layer and the band bending by charge accumulation and depletion on the contact layers which have not been considered in the flat-band model reported by Esaki. so that it is better suited to explain experimental results. The structure used is an $AL_{0.5}Ga_{0.5}AS/GaAs/Al_{0.5}Ga_{0.5}AS$ single quantum well. In this work. we estimate the theoretical current-voltage characteristics of the same structure, and then, the dependence of the current-voltage curves on the thickness of undoped spacer layers sandwiched between the barrier and highly n-doped GaAs contact layer.

• Journal of the Optical Society of Korea
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• 제12권1호
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• pp.42-48
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• 2008

The relative intensity noise (RIN) characteristics in 405 nm blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were investigated using the rate equations with the quantum Langevin noise model. The device parameters were extracted from the optical gain properties of the MQW active region using the self-consistent numerical method developed for calculating the multiband Hamiltonian in the strained wurtzite crystal. These methods have been applied to laser diodes for various conditions including the external feedback and the high frequency current injection.

• 아동학회지
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• 제8권1호
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• pp.15-29
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• 1987

The purpose of the present research was to investigate (I) the acquisition of character constancy of self and others as a function of age; (2) the pattern of acquisition of character constancy, and (3) the relationships between character constancy and conservation of number and mass. The subjects of this study were 160 children, 20 boys and 20 girls at each grade level, kindergarter through grade 3. The Character Constancy Tasks devised bi Rotenberg (1982) and conservation task of number and mass were administered to each child. Chi square, Guttman Scale analysis and Pearson's Correlation were used for the statistical analysis of data. The findings showed that there was increase with age in character constancy of others and of sell in that there was increase with age in children's belief that the characteristics of another person are stable across time and consistent despite changes in a person's appearance. Character constancy of others and of self were acquired in the developmental stages of identity, stability, and consistency. Character constancy of others and self correlated with the conservation of number and mass.

• Journal of Korean Biological Nursing Science
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• 제14권2호
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• pp.77-83
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• 2012

Purpose: The purpose of this study was to identify the self image according to body mass index in middle school students. Methods: The study included 260 students. Self image was measured using structured questionnaires. Statistical analysis was performed using t-test, ANOVA, Scheffe's test and multiple regression analysis. Results: The proportions of under weight, normal weight, and overweight were 36.1%, 53.9%, 10.0% respectively. Also, the mean of the self image score was 4.0. The score of self image was significantly higher in the normal weight group than the over weight group or the under weight group. This trend was also consistent in multiple regression. The score of self image was lower in high school grades, low perceived record, under-weight and over-weight. Conclusion: This study shows that many students are under weight. The score of self image was related with body image. So, level of obesity in each student should also be considered, to elevate the self image.

• 풍력에너지저널
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• 제14권4호
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• pp.43-49
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• 2023

We have studied biofouling in Korea's offshore wind farms by using image analysis through monitoring and surface energy analysis. To observe the biofouling characteristics, samples were fabricated using Micron extra 2 and PropOne, which have a self-polishing property, and Hempathane HS 55610, which is used in substructure coatings. The manufactured samples were installed at the bottom of a ladder in a substructure, and monitored for 10 months. The most biofouling occurred in the sample without the self-polishing property, and algae, barnacles and corallinales were observed. The surface energy analysis used the Owens-Wendt-Rabel and Kaelble (OWRK) model, which uses the contact angles of two standard fluids. As a result of calculating the surface energy using contact angle measurement, the sample without the self-polishing property showed the highest value. This result was consistent with the biofouling incidence observed through monitoring.

• 한국정보시스템학회지:정보시스템연구
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• 제28권4호
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• pp.27-47
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• 2019

Purpose The study examined the key factors influencing the formation mechanism of SNS addiction. Based on the use and gratification theory, we considered relationship maintenance, perceived enjoyment, and self-expression as main desires to induce SNS addiction. The characteristics of SNS users were also considered as major factors affecting SNS addiction. In particular, self-control and subjective well-beings were considered to be prevention factors that could reduce SNS addiction, while SNS relational intimacy was considered to be a facilitator that would increase SNS addiction. Design/Methodology/Approach A structural equation modeling (SEM) method was used to test the theoretical framework based on a sample of 224 Facebook users who have used it more than 6 months. Confirmation factor analysis was conducted to check the reliability, convergent validity, and discriminant validity. Findings Relationship maintenance had a significant effect on self-disclosure intention and SNS addiction, respectively. Perceived enjoyment was significantly related to self-disclosure intention, while it was insignificantly associated with SNS addiction. However, self-expression was not significantly related to both self-disclosure intention and SNS addiction. Consistent with our expectations, both self-control and subjective well-beings had negative effects on SNS addiction. The analysis results found that SNS relational intimacy was positively related to SNS addiction.

• 복식
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• 제52권5호
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• pp.31-45
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• 2002

In this paper. the focus is laid on identifying preferred wedding dress image and its co-relationship with self image of female university students. the biggest potential customer group in the industry. As for the research method. it conducted both review of literature and empirical research method. Through the former approach, four main research questions were derived : 1) What is the preferred wedding dress image of female university students\ulcorner 2) What is the relationship between real self-image and preferred wedding dress image\ulcorner and 3) that between ideal self-image and preferred wedding dress image\ulcorner 4)What is the relationship between the consistency level of the two self-images and preferred wedding dress image\ulcorner In the empirical mode of research, 404 surveys were counted in the final analysis among 450 questionnaires completed by female undergraduate students in Seoul and Chun-an city. Collected data analyzed using factor analysis. frequency analysis. descriptive analysis. scheffe test. multiple-regression analysis and t-test. Results are as follows: first, the sophisticated image was most preferred among female students, followed by elegant splendor. lovable and chaste, feminine and decorative, and characteristic and sexy image. This result indicates how wedding dress trend has a keen sensibility to general fashion trend just like the trend of outfits for everyday life. Secondly, the research results indicated consistent level of co-relationship among the real and ideal self-image and the preference of wedding dress image. And the last the level of consistence between the ideal self-image and the real self-image directly related to the preference level of wedding dress image, showing almost no significance.

• 산업공학
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• 제16권2호
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• pp.229-239
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• 2003

The On-Line Analytical Processing (OLAP) tools access data from the data warehouse for complex data analysis, such as multidimensional data analysis, and decision support activities. Current research has lead to new developments in all aspects of data warehousing, however, there are still a number of problems that need to be solved for making data warehousing effective. View maintenance, one of them, is to maintain view in response to updates in source data. Keeping the view consistent with updates to the base relations, however, can be expensive, since it may involve querying external sources where the base relations reside. In order to reduce maintenance costs, it is possible to maintain the views using information that is strictly local to the data warehouse. This process is usually referred to as "self-maintenance of views". A number of algorithm have been proposed for self maintenance of views where they keep some additional information in data warehouse in the form of auxiliary views. But those algorithms did not consider a consistency of materialized views using view self-maintenance. The purpose of this paper is to research consistency problem when self-maintenance of views is implemented. The proposed "conveyor algorithm" will resolved a complete consistency of materialized view using self-maintenance with considering network delay. The rationale for conveyor algorithm and performance characteristics are described in detail.

• 한국산학기술학회논문지
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• 제21권6호
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• pp.41-50
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• 2020

본 연구의 목적은 취학 전 유아의 학교준비도에 대한 부모와 교사의 중다 평정 결과에 기초한 최적의 잠재계층을 탐색하고, 탐색된 잠재계층에 따른 초등학교 1학년~3학년 시기의 학교적응, 학업수행능력, 문제행동, 자아존중감, 행복감 차이를 검증하는 것이다. 이를 위해 한국아동패널 7차년도(2014년)~10차년도(2017년) 자료의 1,154명을 분석 대상으로 했으며, 잠재프로파일분석, 다변량분산분석, 일원분산분석 방법을 활용하였다. 분석 결과, 첫째, 취학 전 유아의 학교준비도에 대한 부모와 교사의 중다 평정 결과에 기초했을 때, 잠재계층은 '일치된 하 집단', '부모가 교사보다 더 높게 지각한 집단', '교사가 부모보다 더 높게 지각한 집단', '일치된 상 집단'으로 구분되는 것으로 확인되었다. 둘째, 초등학교 1~3학년 시기의 학교적응 차이 검증 결과, '일치된 상 집단'과 '교사가 부모보다 더 높게 지각한 집단'이 '일치된 하 집단'보다 대체로 학업수행적응, 또래적응, 교사적응 모두에서 더 높은 점수를 보였다. 셋째, 초등학교 1~3학년 시기의 학업 수행능력, 문제행동, 자아존중감, 행복감에 차이가 있는지 확인한 결과, '일치된 상 집단'이 '일치된 하 집단'보다 대체로 학업수행능력, 자아존중감, 행복감 수준은 높지만, 문제행동 수준은 낮은 것으로 나타났다. 본 연구결과는 취학 전 유아 시기의 부모와 교사의 중다 평정 결과를 활용하여 학교준비도 수준을 정확하게 이해하고, 이에 기초한 적절한 교육적 도움을 제공하는 것이 초등학교 저학년 시기의 학교생활적응 및 심리적 안녕감에 기여할 수 있음을 시사한다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.325-326
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• 2012

Because steel frame has own characteristics as easy to work and structural safety, it is being increased application by the trend of construction industry has been more higher and larger in today. However, steel frame works have potential problem, so fundamental solution is needed for preventing serious accidents. Recently, self-supported steel joint for enhancing safety is developed in Korea, but this system has some limitations as convenience of work, retainment of consistent productivity. For complementing this limitations, we developed the new system named Automated wire control machine. This study is performed productivity of steel frame work by new system. The basis data for analysing productivity is collected from field test.