• 제목/요약/키워드: Scale-model

검색결과 8,304건 처리시간 0.036초

선천성 심장병 태아를 임신한 임부의 모-태아 애착 및 관련 요인 (Factors associated with Maternal-fetal Attachment of Expectant Mothers Whose Fetus Has a Prenatal Diagnosis of Congenital Heart Disease)

  • 임유미;김은숙;유일영
    • Child Health Nursing Research
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    • 제18권3호
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    • pp.150-156
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    • 2012
  • Purpose: The main purposes of this study were to assess maternal-fetal attachment (MFA) of the expectant mothers of a fetus with a prenatal diagnosis of congenital heart disease (CHD) and to identify factors associated with MFA. Methods: The methodology was a cross sectional survey study using a self-administered questionnaire. Thirty pregnant women carrying a fetus with a prenatal diagnosis of CHD and 30 pregnant women with a normal fetus were enrolled in this study. The MFA Scale and PPS (The Prenatal Psychosocial Profile) were used to collect data. Data were analyzed using SPSS 20.0 Window version. Descriptive statistics, $X^2$-test and t-test were used to compare the two groups. The factors associated with MFA were identified by multiple regression analysis. Results: There was no significant difference between the two groups in MFA and social support from spouse was the only variable showing a significant difference. The model from the multiple regression analysis explained 33.8% of MFA for both groups. Conclusion: MFA of expectant mothers with a prenatal diagnosis of CHD and of mothers with a normal fetus were not significantly different. It is important that health care providers encourage expectant fathers to support the expectant mothers to increase MFA.

An electromechanical impedance-based method for tensile force estimation and damage diagnosis of post-tensioning systems

  • Min, Jiyoung;Yun, Chung-Bang;Hong, Jung-Wuk
    • Smart Structures and Systems
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    • 제17권1호
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    • pp.107-122
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    • 2016
  • We propose an effective methodology using electromechanical impedance characteristics for estimating the remaining tensile force of tendons and simultaneously detecting damages of the anchorage blocks. Once one piezoelectric patch is attached on the anchor head and the other is bonded on the bearing plate, impedance responses are measured through these two patches under varying tensile force conditions. Then statistical indices are calculated from the impedances, and two types of relationship curves between the tensile force and the statistical index (TE Curve) and between statistical indices of two patches (SR Curve) are established. Those are considered as database for monitoring both the tendon and the anchorage system. If damage exists on the bearing plate, the statistical index of patch on the bearing plate would be out of bounds of the SR curve and damage can be detected. A change in the statistical index by damage is calibrated with the SR curve, and the tensile force can be estimated with the corrected index and the TE Curve. For validation of the developed methodology, experimental studies are performed on the scaled model of an anchorage system that is simplified only with 3 solid wedges, a 3-hole anchor head, and a bearing plate. Then, the methodology is applied to a real scale anchorage system that has 19 strands, wedges, an anchor head, a bearing plate, and a steel duct. It is observed that the proposed scheme gives quite accurate estimation of the remaining tensile forces. Therefore, this methodology has great potential for practical use to evaluate the remaining tensile forces and damage status in the post-tensioned structural members.

Exercise Self-Efficacy as a Mediator between Goal-Setting and Physical Activity: Developing the Workplace as a Setting for Promoting Physical Activity

  • Iwasaki, Yoshie;Honda, Sumihisa;Kaneko, Shuji;Kurishima, Kazuhiro;Honda, Ayumi;Kakinuma, Ayumu;Jahng, Doosub
    • Safety and Health at Work
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    • 제8권1호
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    • pp.94-98
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    • 2017
  • Background: Physical activity (PA) is ranked as a leading health indicator and the workplace is a key setting to promote PA. The purpose of this study was to examine how goal-setting and exercise self-efficacy (SE) during a health promotion program influenced PA level among Japanese workers. Methods: Using a cross-sectional study design, we surveyed 281 employees. The short version of the International Physical Activity Questionnaire was used to assess PA level. Exercise SE was assessed using a partially modified version of Oka's exercise SE scale. Personal goals were assessed as the total numbers of "yes" responses to five items regarding "details of personal goals to perform PA". A mediational model was used to examine whether exercise SE mediates between the number of personal goals and PA level. Results: The mean age of the participants was 46.3 years, 76.2% were men, and the most common occupational category was software engineer (30.6%). The average PA level per week exceeded the recommended level in 127 participants (45.2%). One hundred and eighty-four participants (65.5%) set some form of concrete personal goal to perform PA. The relationship between the number of personal goals and PA level was mediated by exercise SE. Conclusion: Our study showed that exercise SE mediates goal-setting and increases PA. The results suggest that the components of PA promotion programs should be tailored to enhance participants' confidence in performing PA.

인터넷 쇼핑몰의 고객구성 평가 모델에 관한 연구 (A Study on Model for the Evaluation of Customer Composition in Internet Shopping Malls)

  • 박광호;한동석;김학소;백동현
    • 산업경영시스템학회지
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    • 제29권2호
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    • pp.83-91
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    • 2006
  • Internet shopping mall has become a huge distribution channel with dramatic growth in recent years. The number of consumers has exponentially increased as the scale of shopping mall has been large so that shopping malls with thousands or millions of consumers become a general case. However, it is essential to evaluate whether current assortment of consumers is proper or not in the strategic aspect in order to operate Internet shopping mall effectively and gain profits. That is, it is important to evaluate whether consumer strategy of corporation is proper or not from the corporation. Despite this business importance, consumer assortment has not been evaluated well and related study is not sufficient. This study supposes a framework for consumer assortment evaluation, which evaluates whether consumer assortment of Internet shopping mall is proper or not. In the framework for consumer assortment evaluation, analysis data based on order data and consumer data in database is made. Then, four factors, consumer maintenance rate, consumer profitability, consumer securing rate and consumer conversion are setup, and 22 measurement indexes are drawn. Finally, a consumer assortment evaluation score card is made by integrating them. This study has applied a supposed framework to a domestic typical community based shopping mall, and it is expected that the evaluation result will be used as informant strategic information to operate the shopping mall effectively.

지상형 탄약고의 내부온도 감소 방안 연구 (A Study on the Deduction of Internal Temperature of the Ground Magazine)

  • 박형주;최명진;양재경
    • 산업경영시스템학회지
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    • 제36권3호
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    • pp.142-149
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    • 2013
  • Among ammunitions which are stored in a war field, the lifespan of propelling gunpowder is affected by storage environment such as storage temperature, humidity, and exposure to sunlight. These are because Nitrocellulose (NC) which is the main component of propelling gunpowder can be naturally disassembled to unstable substances similar with other nitric acid ester. We can't prevent it fundamentally from being disassembled, but to restrain induction of automatic disassembly by decomposition product, a decomposition product ($NO_2$, $NO_3$, and $HNO_3$) and tranquillizer DPA (Diphenylamine), having high reactivity, are added into a propellant. For this, it will decrease the velocity of tranquillizer which can also affect the velocity of producing the decomposition product of NC, storage temperature or humidity of propelling gunpowder is higher, drop of tranquillizer content is much faster. Therefore, to extend storage lifespan of propelling gunpowder, it is really important to control storage temperature or humidity inside the magazine. Hereupon, according to the manufacture of small scale model magazine and the result of performing experiments and measuring variation of inside temperature (storage temperature), using roof types that have a steel slate structure of magazine among ground magazines, this research shows the differences in details.

Reynolds and froude number effect on the flow past an interface-piercing circular cylinder

  • Koo, Bonguk;Yang, Jianming;Yeon, Seong Mo;Stern, Frederick
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제6권3호
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    • pp.529-561
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    • 2014
  • The two-phase turbulent flow past an interface-piercing circular cylinder is studied using a high-fidelity orthogonal curvilinear grid solver with a Lagrangian dynamic subgrid-scale model for large-eddy simulation and a coupled level set and volume of fluid method for air-water interface tracking. The simulations cover the sub-critical and critical and post critical regimes of the Reynolds and sub and super-critical Froude numbers in order to investigate the effect of both dimensionless parameters on the flow. Significant changes in flow features near the air-water interface were observed as the Reynolds number was increased from the sub-critical to the critical regime. The interface makes the separation point near the interface much delayed for all Reynolds numbers. The separation region at intermediate depths is remarkably reduced for the critical Reynolds number regime. The deep flow resembles the single-phase turbulent flow past a circular cylinder, but includes the effect of the free-surface and the limited span length for sub-critical Reynolds numbers. At different Froude numbers, the air-water interface exhibits significantly changed structures, including breaking bow waves with splashes and bubbles at high Froude numbers. Instantaneous and mean flow features such as interface structures, vortex shedding, Reynolds stresses, and vorticity transport are also analyzed. The results are compared with reference experimental data available in the literature. The deep flow is also compared with the single-phase turbulent flow past a circular cylinder in the similar ranges of Reynolds numbers. Discussion is provided concerning the limitations of the current simulations and available experimental data along with future research.

효과적인 오류 추적을 위한 수직적 시스템 시험 방법 (Vertical System Testing Method For Efficient Error Tracing)

  • 서광익;최은만
    • 한국컴퓨터정보학회논문지
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    • 제13권2호
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    • pp.19-29
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    • 2008
  • 단위 시험은 모듈의 소스 코드를 면밀히 검토하면서 논리적 오류나 문장 오류 등이 있는지 분석하는 화이트박스 시험이 가능하다. 반면 시스템 수준의 기능 시험은 규모가 크기 때문에 시험 데이터를 입력한 후 출력된 결과가 예상 결과와 같은지 비교하는 블랙박스 시험이 주를 이룬다. 이러한 시스템 시험 단계에서 사용하는 블랙박스시험은 오류를 발견하더라고 수정을 위해 소스 코드를 추적하기 어려운 문제점이 있다. 뿐만 아니라 시스템 시험 단계에 화이트박스 시험을 사용하는 것은 시험 대상의 추상 수준 달라 쉽지 않다. 이에 본 논문에서는 시스템의 기능처럼 높은 추상 수준을 시험 대상으로 하되 소스 코드 수준까지 화이트박스 스타일로 시험할 수 있는 현실적이고 통합된 시스템 수준의 수직적 시험에 대해 제안한다. 그리고 어떻게 수직적 시험을 적용하는지 UML명세 모델에서 소스코드까지 오류를 추적하는 방법을 사례를 통해 설명하고 더불어 오류 추적의 효과성을 보였다.

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하천에 순간 유입된 오염물질의 거동 특성 분석 (Analysis of Behavior Characteristics of Instantaneous Input of Pollutant in River)

  • 윤세의;고재형;김수열
    • 한국수자원학회논문집
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    • 제36권4호
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    • pp.575-586
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    • 2003
  • 하천에 오염물질이 순간적으로 유입된 경우에는 연속적인 유입의 경우와 다르게 분산계수의 변화에 따라 오염물질의 거동 특성이 민감하게 변한다. 하천에 순간적으로 유입된 오염물질의 거동특성을 분석하기 위하여 한강하류부에서 수리인자 및 수질인자를 실측하였다. 분산계수 추정에 사용되는 경험식에 실측된 수리인자를 적용하여 갈수시 한강하류부의 분산계수의 규모를 분석하고, 적용 가능성이 큰 경험식을 제시하였다 또한, 실측된 수질인자를 RMA-4 모형의 계산치와 비교하여 만족할 만한 결과를 얻었다. 한강하류부에 순간적으로 유입된 오염물질의 분산계수, 하류단 수위 등의 변화에 따라 오염물질의 분산범위, 분산경로, 최초 및 최대농도 도달시간 등을 파악하였다.

자연하천 형상을 이용한 최적 흐름분배 알고리즘의 개발 (Development of Optimized Flow Apportioning Algorithm Using Natural Stream Morphology)

  • 김상현;이학수;강창용;김남원
    • 한국수자원학회논문집
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    • 제35권4호
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    • pp.345-358
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    • 2002
  • 수치고도모형을 이용한 흐름분배 알고리즘들은 지형을 따른 흐름의 분산특성을 잘 기술해 주는 방향으로 발달되어 왔지만, 수로격자의 연결성, 지형기복을 따른 다양한 분산특성, 수로격자크기 등과 관련한 한계성을 가지고 있다. 기존 흐름 알고리즘들이 흐름분배 결정에 사용한 지형 데이터들은 수치고도모형에서 산출가능한 흐름누적면적과 경사도로서 유역내 지배적인 흐름경로인 수로격자의 위치와 크기에 대한 고려를 하지 않는다. 따라서 본 연구에서는 기존 알고리즘들의 단점인 수로의 연결성과 복잡한 지형을 따른 다양한 흐름분산 특성을 기술할 수 있는 흐름 분배 알고리즘을 제안하고, 유전자 알고리즘을 이용하여 수로격자의 위치와 크기를 가장 잘 표현할 수 있도록 최적화하였으며, 기존의 방법에 비해 개선된 결과를 얻을 수 있었다.

토목섬유를 활용한 인공리프의 기능에 관한 연구 (A Study on function of Artificial Reef by Using Geotexile Tube)

  • 신문섭;안경수;신은철
    • 한국수자원학회논문집
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    • 제36권4호
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    • pp.623-631
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    • 2003
  • 본 연구에서는 유의파고별, 지오 튜브의 채움비, 지오 튜브 천단고의 변화에 따라 지오 튜브의 안정 및 소파성능에 관한 실험을 실시하였다. 축척은 1/50로 하여 조파 수로내에 모형을 설치하였다. 안정성 시험은 유의파고를 재현하여 지오 튜브의 변위를 계측하여 검토하였다. 지오 튜브의 각 부분의 변위량을 관찰하기 위하여 바닥에 메쉬를 설치하여 계측하였으며 지오 튜브 상부에 기준선을 표시하고 10cm 간격으로 초기 위치점을 설정하여 계측하였다. 소파성능은 지오 튜브의 설치전과 설치후의 각각의 채움비에 따라 천단고가 있는 경우와 없는 경우 파고전달율 해석하여 비교 분석하였다.