• Title/Summary/Keyword: Theoretical study

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A Theoretical Study for Stack Effect driven Natural Ventilation System in High-rise Building (고층건물에서 연돌효과를 활용한 자연환기시스템 설계를 위한 이론적 고찰)

  • Yoon, Sung-Min;Seo, Jung-Min;Kim, Yang-Soo;Lee, Joong-Hoon;Song, Doo-Sam
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.123-129
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    • 2009
  • In these days, the green building movement caused by the energy crisis is increasing, passive design is getting mere and more attention as it provides many possibilities for energy conservation. Moreover, with the increasing social intention for healthy life, the demand for indoor air Quality is increasing in Korea. As result, the ventilation system which can provide the sound outdoor air constantly has been obliged in Korea. So, the hybrid system which using natural power and mechanical power and makes up for the shortage of mechanical and natural ventilation attracts people's attention in Korea. As a hybrid ventilation system, in this study, the stack effect driven hybrid ventilation system in high-rise residential building will be suggested. And in this paper, the theoretical review for hybrid ventilation system suggested in this study will be addressed. Especially, the characteristics of pressure distribution and airflow caused by stack effect in high-rise residential building and the possibility of natural ventilation as results of stack effect will be described.

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A Study on the Development and Commercialization Trends of Wearable Fashion Products Using Flexible Displays (플렉시블 디스플레이가 이용된 웨어러블 패션 제품 개발 및 상용화 동향에 관한 연구)

  • Lee, Hyewon
    • Journal of Fashion Business
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    • v.25 no.4
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    • pp.125-140
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    • 2021
  • Recently, flexible displays have been used as part of fashion beyond the concept of parts for electronic products. The flexible display applied to wearable fashion products flexibly bends according to the wearing position of the human body and, at the same time, decorates the fashion product more splendidly through the screen on which images or videos are displayed. Flexible displays, which are used for clothes and accessories, combine analogue fashion sensibility with digital screens to create a new level of convergence product design and expand the range of fashion design and fashion materials. This study aims to analyze the trends of the development and commercialization of fashion products that use flexible displays. As a research method, theoretical research and empirical research through case analysis were conducted in parallel. First, as a theoretical study, the morphological and technical characteristics of flexible displays were examined. Through theoretical studies, the effect of the characteristics of flexible displays on the development of wearable fashion products was investigated. Second, as an empirical case study, the design of wearable fashion products using flexible displays over the past 10 years and the characteristics of the displays used in the products were analyzed. Based on the characteristics analyzed, the product design, display and product integration methods and the commercialization stages of wearable fashion products using flexible displays were analyzed.

A Review on Child Studies for 20 Years: How Much did the Studies Contribute to Society\ulcorner (가정관리학의 아동분야연구 20년의 평가 - 실천적 연구를 중심으로 -)

  • Rhee, Ock
    • Journal of Families and Better Life
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    • v.18 no.1
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    • pp.203-216
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    • 2000
  • This study was to review the child research articles in the field of home economics in Korea for the last two decades and to evaluate the child studies in terms of home much the child research had contributed to society. For the purposes of this study all the child research articles that had been published in the three representative academic journals of Korea were reviewed. A framework to evaluate child studies was decided in accordance with objectives of the research theoretical and practical, Theoretical studies imply ones dealt with child development and personality parent-child relations development of measures and thoughts on children while practical studies mean the research on development of parent education programs child education programs mental health of children wellbeing of children and child welfare policies. Results of qualntitative analysis in this study showed increases in numbers of both theoretical and practical studies. Practical studies however occupied j st 4-12% of all the research article published in the last 20 years. The Results of this study indicated researcher' low involvement in pratical studies. Researchers in the field of child studies had most frequently conducted research on child development and parent-child relations which were conducted based on theoretical knoledges from the West. For the practical child studies there were some studies on developing parent education programs and a few articles dealt with child welfare policies and wellbeing of children for two decades. Furthermore the major variables of the practical studies were analyzed and evaluated with respect to their contribution to society as well as socializing child relate issues. Finally the reasons of scholars' low involvement in practical studies and some suggestions for further studies to deal with practical child issues were discussed.

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Comparison and Analysis for Evaluation of Ride and SEAT Index through Theoretical Seat-Human Body Model and Vehicle Test (시트-인체 해석 모델링과 차량 주행 시험을 통한 차량 승차감 평가와 시트 지수의 비교 및 분석)

  • Son, In-Suk;Kim, Jung-Hoon;Kang, Yeon-June
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.4
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    • pp.1-9
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    • 2009
  • A simplified model of seat-human body is presented to analyze vibrations of human body on a seat of vehicle. The theoretical model having seven degrees-of-freedom is composed of the inter-connected masses, springs and dampers. Until now, evaluation of ride comfort has been usually performed only through vehicle tests. This study aims to complement shortcomings of conventional vehicle tests in evaluation of ride comfort by using the theoretical model. The acceleration values of the human body are obtained from frequency response functions of the theoretical model. Thereafter, Ride and SEAT indexes are acquired by considering response characteristics of the human body for the 12 axes that are presented in BS 6841. A vehicle test is carried out to measure the acceleration values for the three parts of the human body such as upper body, hip and foot. Ride and SEAT indexes of the vehicle test are also obtained by considering the response characteristics of the human body, of which results are compared with the values from the theoretical model. It is found that the theoretical results are in good agreement with the experimental results.

Comparison of the Practical and Theoretical Knowledge of the Hepatitis B Virus among Dental Hygiene Students

  • Ertem, Sinan Yasin;Ozdogan, Sertac;Ozturk, Ayla;Akcam, Ozge
    • Journal of dental hygiene science
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    • v.20 no.3
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    • pp.136-145
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    • 2020
  • Background: Hepatitis B is an important public health problem as one of the leading causes of morbidity and mortality. The aim of this study was to compare the theoretical and practical knowledge levels of dental assistant students about Hepatitis B Virus. Methods: The 1st and 2nd grade students of the Oral and Dental Health program were invited to participate in the survey. Out of the 68 invited students, 61 completed the questionnaire. The average ages of the male and female students surveyed were 20.27±1.45 and 19.56±1.16, respectively. A total of 34 questions were asked, of which 15 measured basic theoretical knowledge and 19 assessed basic practical knowledge. Results: There was no statistically significant difference between the students' knowledge for each question according to their sex and grade. When the questionnaire was grouped into basic theoretical and basic practical knowledge levels, both were observed to be high. While the lowest correct answer rate was 35.00% for the questions about practical applications, it was 31.14% for the questions measuring the level of theoretical knowledge. There was no statistically significant difference when the levels of knowledge of 1st and 2nd grade students were compared. Students answered the majority of the questions correctly, and ranged between 71% and 100%. Conclusion: Students' high level of basic theoretical knowledge can be a result of their in-class education on the fundamentals. However, their knowledge about the correct approaches in practical applications indicates the beneficial role of having well-defined criteria and prevention protocols that are required in hospitals and the effectiveness of their environmental orientations.

Estimation Method of Earth Pressures Acting on a Row of Piles due to Lateral Soil Movements (측방변형지반속 줄말뚝에 작용하는 토압의 산정법)

  • 홍원표;송영석
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.13-22
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    • 2004
  • In case of the lateral movement accurring at soft ground where a row of piles are installed, the crown failure at external arch zone of soil arching is firstly developed, and the cap failure at wedge zone in front of piles is lastly developed. Therefore, the lateral earth pressure acting on a row of piles due to soil movement should be calculated in each condition of crown and cap failures around piles. A theoretical equation of crown failure can be proposed using a cylindrical cavity expansion theory. The theoretical equation of crown failure is mainly affected by two factors. One is related to soil properties such as internal friction angle, cohesion and horizontal pressure, and the other is related to pile factors such as diameter, installation interval. Meanwhile, the yield range of lateral earth pressure is established in the estimation of theoretical equation based on crown and cap failures around piles. The theoretical values based on crown and cap failures are compared with the experimental values. The experimental values are located in the range proposed by theoretical values. Thus, it is confirmed that the theoretical values proposed in the study are very reasonable.

Review of the Research & Development of "New Retailing" (중국 "신소매(新零售)"에 관한 연구개발 동향 분석)

  • Wu, Li-Yan;Han, Jung-Soo;Kim, Hyung-Ho
    • Journal of the Korea Convergence Society
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    • v.10 no.6
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    • pp.15-24
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    • 2019
  • The development of "New Retailing" is still in its infancy. Theoretical research has just begun, showing the characteristics of practice leading theoretical research, that is, there is more practical exploration but relatively insufficient theoretical research. At present, the theoretical research and practice development of "New Retailing" is gradually clear. The future development trend is large-scale, no boundaries, and wisdom. The academic community should further study in depth with theory and practice, focusing on the deep integration of online and offline, the new logistics under "New Retailing", and the research direction of "New Retailing" driving supply chain transformation and reconstruction so as to better guide the development of "New Retailing". The purpose of the research is to sort out the research status and theoretical situation of "new retailing", so as to provide references for further research on "new retail" and guidance for practical development.

Theoretical Models for Predicting Racking Resistance of Shear Walls (전단벽의 전단성능 예측 모형)

  • Jang, Sang Sik
    • Journal of the Korean Wood Science and Technology
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    • v.30 no.4
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    • pp.96-105
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    • 2002
  • Shear wall is the most important component resisting lateral loads imposed to a building by wind or earthquake. In shear walls, lateral load applied to framing is transmitted to sheathing panel through nailed joints between sheathing and framing so that the load is resisted by in-plane shear strength of sheathing. Therefore, nailed joints are the most basic and important component in the viewpoint of stiffness and strength of shear walls. In this study, stiffness and strength of single nailed joint were measured by single shear tests of nailed joints and used as input for theoretical models developed to estimate racking behavior of shear walls. And shear walls were tested to check the accuracy of theoretical models estimating racking resistance of shear walls. Stiffness of nailed joint was affected by grain direction of stud but direction of sheathing panel had little effect. Behavior of nailed joint and shear walls under lateral loads could be represented by three lines. Theoretical model II was more accurate than theoretical model I in estimating racking behavior of shear wall under loads.

Evaluation of dynamic muscle fatigue model to predict maximum endurance time during forearm isometric contraction (전완의 등척성 수축시 최대근지구력시간을 예측하기 위한 동적근피로모델의 평가)

  • Kiyoung, Lee
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.15 no.6
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    • pp.433-439
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    • 2022
  • Muscle fatigue models to predict maximum endurance time (MET) are broadly classified as either 'empirical' or 'theoretical'. Empirical models are based on fitting experimental data and theoretical models on mathematical representations of physiological process. This paper examines the effectiveness of dynamic muscle fatigue model as theoretical model to predict maximum endurance time during forearm isometric contraction. Forty volunteers (20 females, 20 males) are participated in this study. Empirical models (exponential model and power model) and theoretical model (dynamic muscle fatigue model) are used to compare. Mean absolute deviation (MAD), correlation coefficient (r) and intraclass correlation (ICC) are calculated between theoretical model and empirical models. MAD are below 3.5%p, r and ICC are above 0.93 and 0.87, respectively. This results demonstrate that dynamic muscle fatigue model as theoretical model is valid to predict MET.