• Title/Summary/Keyword: longitudinal studies

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Correlation of aerodynamic forces on an inclined circular cylinder

  • Cheng, Shaohong;Tanaka, Hiroshi
    • Wind and Structures
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    • v.8 no.2
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    • pp.135-146
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    • 2005
  • Divergent galloping-like motion of a dry inclined cable has been observed in a limited number of experimental studies, which, due to the uncertainties in its onset conditions, has induced serious concerns in the bridge stay cable design. A series of dynamic and static model wind tunnel tests have been carried out to confirm the existence of the phenomenon and clarify its excitation mechanism. The present paper focuses on exploring the spatial flow structure around an inclined cable. The pattern of resultant aerodynamic forces acting at different longitudinal locations of the model and the spatial correlation of the forces are examined. The results lead one step closer in revealing the physical nature of the phenomenon.

Molecular Simulation Studies of Scattered and Penetrated Hydrogen Ions I. Normal Incident Angle to Ni (100) Surface (산란 및 투과된 수소 이온의 분자 전산 연구 I. 니켈 (100) 표면의 직각 입사)

  • Suh, Soong-Hyuck;Min, Woong-Ki
    • Transactions of the Korean hydrogen and new energy society
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    • v.11 no.3
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    • pp.127-136
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    • 2000
  • Molecular dynamics simulations have been carried out to investigate the scattering and penetration properties of hydrogen ions with the normal incident angle to Ni (100) surface. The initial kinetic energies of hydrogen ions range from 100 to 1,600 eV. The simulation results are used to assess the applicabilities of theoretical predictions based on the binary collision approximation, and, in the high kinetic regime, theoretical results for scattering energies were shown to he a good agreement with molecular simulations. The angle dependencies on both scattering and penetration distributions were found in the longitudinal direction, but not in the azimuthal direction except for the high kinetic energy of 1,600 eV.

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Seismic Retrofit of 1/2 Scale-down Circular RC Columns with GFRP Wrapping (1/2 축소된 원형교각의 GFRP 래핑 내진보강)

  • Youm, Kwang-Soo;Choi, Young-Min;Lee, Young-Ho;Kwon, Tae-Gyu;Kim, Jung-Ho;Hwang, Yoon-Koog
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.250-253
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    • 2006
  • This paper presents experimental studies on investigating the seismic retrofit performance of reinforced concrete circular columns with poor lap-splice details using GFRP wrapping. Four 1/2 scale-down model columns have been tested. The as-built column is expected to suffer brittle failure due to the bond failure of lap-spliced longitudinal reinforcement. The retrofitted columns using GFRP wrapping showed significant improvement of seismic performance.

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Hemodynamic Analysis of Pig's Left Common Coronary Artery (I) (좌주간부 관상동맥에 관한 혈류역학적 분석 (I))

  • Park, Jung-Su;Chang, Ju-Hee;Moon, Su-Yeon;Shin, Se-Hyun
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1923-1929
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    • 2003
  • The present study investigated the microcirculation of blood in the left common artery (LCCA). In order to develop a mathematical model for microcirculation in LCCA, the present study adopted preexisted set of measured morphological data on anatomy, mechanical properties of the coronary vessels, viscosity of blood, the basic laws of physics, and the appropriate boundary conditions. In this study, the statistical distribution of blood pressure, blood flow, and blood volume in the LCCA were determined based on the anatomical branching pattern of the coronary arterial tree and the statistical data of blood vessel dimensions. Our calculations were in good agreement with the previous studies. The present results showed that the mean longitudinal pressure drop profile was function of the vessel order numbers. It was found that the normalized pressure drop was a logarithmic function of the compliance.

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A Framework for Analyzing the Roles of Information Systems in the Automobile Industry (자동차 산업에서 정보시스템의 역할 분석을 위한 프레임워크)

  • Yoon, Jong-Soo;Kim, Yoo-Jeong;Han, Jae-Min
    • Asia pacific journal of information systems
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    • v.12 no.1
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    • pp.17-44
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    • 2002
  • This study is to propose a framework for analyzing the role of information systems in organizations, and to make an overture it's applicability for empirical studies to be performed in the future. To accomplish these purposes, this study identified major dimensions which can explain the introduction of various applications based on the interviews with IS staffs of a domestic car manufacturing firm, and reviewed the past researches which discussed the roles of information systems regarding those dimensions. From this mixed approach, this study defined the research dimensions to analyze the role of information systems, which are consisted of the purpose of information processing and the scope of information processing. And then, this study performed the longitudinal case study to analyze the role of information systems in organizational growth based on the framework.

Free Vibrations of Curved Beams with Elastic Springs (스프링으로 탄성 지지된 곡선보의 자유진동)

  • 이병구;진태기;이태은
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.875-880
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    • 2001
  • This paper deals with the free vibrations curved beams with elastic springs. Taking into account the effects of rotatory inertia and shear deformation, differential equations governing the free vibrations of such beams are derived, in which each elastic spring is modeled as a discrete Winkler foundation with very short longitudinal length. Differential equations are solved numerically to calculate natural frequencies and mode shapes. In numerical examples, the circular, parabolic, sinusoidal and elliptic curved members are considered. The parametric studies are conducted and the lowest four frequency parameters are reported in tables and figures as the non-dimensional fonns. Also the typical mode shapes are presented.

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A study for CWR on Steel Plate Girder Railway Bridge without Ballast (무도상 교량 특성을 고려한 장대화 방안에 관한 연구)

  • Min Kyung-Joo;Nam Bo-Hyun;Ban Geol yeong
    • Proceedings of the KSR Conference
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    • 2005.05a
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    • pp.706-711
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    • 2005
  • From the using CWR (Continuously Welded Rail) on steel plate girder bridges without ballast, axial forces are occurred from a temperature on CWR and girders. Because of the additional axial forces, studies in order to CWR and developments of devices are proceeding. The track system of steel plate girder bridges is poor. When CWR is used for the system, the resistance on sleepers is increased from a temperature. So it is increasing an effect on CWR and, for solving the effect, longitudinal forces for buckle are being decreased. It is possible that opposite cases can be happened and it is also compared and studied. Therefore, we present a reasonable model for analyzing CWR within the property of steel plate girder railway bridges in Korea. Furthermore, the results analyzed for stability is compared and evaluated with tests. Finally, a reasonable method for the installation of CWR on bridges without ballast is suggested.

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A Study on Spatial and Temporal Distribution of a Pest via Generalized Linear Mixed Models (일반화선형혼합모형을 통한 해충밀도의 시공간분포 연구)

  • 박흥선;조기종
    • The Korean Journal of Applied Statistics
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    • v.17 no.2
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    • pp.185-196
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    • 2004
  • It is an important research area in Integrated Pest Management System to estimate the pest density within plants, because the artificial controls such as spraying pesticides or biological enemies depend on the information of pest density. This paper studies the population density distribution of two-spotted spider mite in glasshouse roses. As the data were collected repeatedly on the same subject, Subject-Specific and Population Averaged approaches are used and compared.

Family Relations in Later Life : A Review and Prospect of Research During the Past 15 Years (노년기 가족관계에 대한 선행연구 고찰 : 현황과 과제)

  • Cho, Byung-Eun
    • Journal of Families and Better Life
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    • v.25 no.1 s.85
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    • pp.59-75
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    • 2007
  • This review synthesizes research during the past 15 years on the family relations of older persons. After discussing two background issues-sociodemographic changes of later life families and the status of the elderly-the following topics are addressed; relationships between aged parents and adult children, couple relationships, grandparents' relationship with their grandchildren and sibling relationships. Family relationships are vital support systems providing emotional and instrumental support in the lives of older persons. Mutual assistance and affection among family members were found to be common characteristics. Although research on family gerontology has increased in quantify, there are feater needs to develop qualitative, longitudinal and theory grounded studies to capture the rich complexity of family life. Other challenges and suggestions for future research on older persons' family relationship are presented.

Theoretical Review on Burnout Symptoms in Education (교육에서의 소진에 관한 이론적 고찰)

  • Lee, Sang Min;An, Sunghee
    • Korean Medical Education Review
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    • v.16 no.2
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    • pp.57-66
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    • 2014
  • Burnout research has mostly been performed in human service fields. However, it has recently been expanded to cover diverse settings and even non-occupational samples, such as students. In this study, we defined the construct of academic burnout, which is the burnout experienced by students. Next, we described the concept of academic burnout by introducing measurements for assessing academic burnout. On the basis of the demand-control model (DCM) and effort-reward imbalance model (ERIM), which are the most predominant theoretical burnout models, we described the causal factors and the pathway to experiencing academic burnout symptoms. The ERIM was a more influential model than the DCM when explaining the academic burnout of Korean students. Based on the results of previous longitudinal studies on academic burnout, we recognized emotional exhaustion and academic inefficacy as the initial symptoms of academic burnout. Finally, we discussed the prevention and intervention programs with specific components that should be included in those programs.