• Title/Summary/Keyword: Multiple-body problem

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Unified Theory for the Radiation Problem of Multiple Slender Bodies

  • Kim, Yong-Hwan
    • Journal of Ship and Ocean Technology
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    • v.7 no.2
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    • pp.1-19
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    • 2003
  • This paper introduces a unified theory for the radiation problem of adjacent multiple floating bodies. The particular case of interest is the multiple slender bodies that their centerlines are parallel. The infinite-and finite-depth unified theories for the single-body problem are extended to solve each sub-problem of multiple bodies. The present method is valid for deep water and moderate water depth, and applicable for individually floating bodies as well as multimaran-type vehicles. For the validation of the present method, the heave and pitch hydrodynamic coefficients for two adjacent ships are compared with the results of a three-dimensional method, and an excellent agreement is shown. The application includes the hydrodynamic coefficients and motion RAOs of four trimarans which have different longitudinal and transverse arrangements for sidehulls.

Dynamic Analysis of Multiple-Body Floating Platforms Coupled with Mooring Lines and Risers

  • Kim Young-Bok;Kim Moo-Hyun
    • Journal of Ship and Ocean Technology
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    • v.9 no.1
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    • pp.11-26
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    • 2005
  • In this study, the program to investigate the multiple body interaction effects between a floating platform and a shuttle tanker considering the coupled effect of hull (FPSO) with mooring lines and risers was developed. The coupled analysis program, which is called WINPOST-MULT using the hydrodynamic analysis results by WAMIT, was made. For the verification of WINPOST-MULT by means of numerical experiments, two multiple-body models of an FPSO-FPSO and an FPSO-shuttle tanker system are adopted. With the FPSO-FPSO model and a two-mass-spring system to idealize two identical bodies for the 100-year storm wave condition in GOM, the numerical simulations were performed to investigate the interaction effects between two identical bodies. For the more reality, the coupled analysis for the FPSO-shuttle tanker model in the tandem arrangement was carried out in the consideration of the environmental condition of the West Africa Sea as a rather mild condition. Through the case studies with interaction effect and without interaction effect by the iteration method and the combined method, it is verified that the program is a very useful tool for the analysis of the interaction problem of multiple-body system and the coupled problem of the hull/mooring/riser.

DEVELOPMENT OF AERODYNAMIC SHAPE OPTIMIZATION TOOLS FOR MULTIPLE-BODY AIRCRAFT GEOMETRIES OVER TRANSONIC TURBULENT FLow REGIME (천음속 난류 유동장에서의 다중체 항공기 형상의 공력 설계 도구의 개발)

  • Lee, B.J.;Lee, J.S.;Yim, J.W.;Kim, Chong-Am
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.100-110
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    • 2007
  • A new design approach for a delicate treatment of complex geometries such as a wing/body configuration is arranged using overset mesh technique under large scale computing environment for turbulent viscous flow. Various pre- and post-processing techniques which are required of overset flow analysis and sensitivity analysis codes are discussed for design optimization problems based on gradient based optimization method (GBOM). The overset flow analysis code is validated by comparing with the experimental data of a wing/body configuration (DLR-F4) from the 1st Drag Prediction Workshop (DPW-I). In order to examine the applicability of the present design tools, careful design works for the drag minimization problem of a wing/body configuration are carried out by using the developed aerodynamic shape optimization tools for the viscous flow over multiple-body aircraft geometries.

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Effects of the Science Project Activities Based on Multiple Intelligences on the Elementary School Children s Problem Solving Behaviors (다중지능에 기초한 과학 프로젝트 활동이 초등학교 아동의 문제해결 행동에 미치는 영향)

  • 임채성;왕경순
    • Journal of Korean Elementary Science Education
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    • v.19 no.1
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    • pp.71-83
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    • 2000
  • This study examined the influences of science project activities based on multiple intelligences on problem solving behaviors of elementary school children. Specifically, the influences of the project activities on the problem solving skills and propensities of the children were investigated. Forty-four fifth graders were selected for the study. They performed the projects and made their products of it during five months on the units of "Weather" and "Our Body" Criteria for assessment of problem solving abilities were determined. The patterns reflected in products of the project activities were examined, then the observation of the subjects' problem solving behaviors and the interviews were performed based on the criteria. The results were analyzed through both of qualitative and quantitative approaches. In these analyses, the implementation of the science projects was found to contribute to the improvement in all sub-factors of problem solving, specially, skills associated with the propensities of problem identification and of the collection, analysis, and synthesis of data significantly increased

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Time-Domain Analysis on Motion Response of Adjacent Multiple-Bodies in Waves (파랑 중 근접한 다중 물체의 운동응답에 대한 시간영역 해석)

  • Kim, Kyong-Hwan;Kim, Yong-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.1
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    • pp.63-72
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    • 2008
  • This study considers the motion response of multiple adjacent floating bodies in waves. As a method of solution, a three-dimensional Rankine panel method is adopted in time domain. For the validation of the developed numerical method, the motions of two adjacent Series 60 hulls and ship-barge model are estimated. The computational results are compared with other numerical and experimental analyses, showing favorable agreement.

Impact onto an Ice Floe

  • Khabakhpasheva, Tatyana;Chen, Yang;Korobkin, Alexander;Maki, Kevin
    • Journal of Advanced Research in Ocean Engineering
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    • v.4 no.4
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    • pp.146-162
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    • 2018
  • The unsteady problem of a rigid body impact onto a floating plate is studied. Both the plate and the water are at rest before impact. The plate motion is caused by the impact force transmitted to the plate through an elastic layer with viscous damping on the top of the plate. The hydrodynamic force is calculated by using the second-order model of plate impact by Iafrati and Korobkin (2011). The present study is concerned with the deceleration experienced by a rigid body during its collision with a floating object. The problem is studied also by a fully-nonlinear computational-fluid-dynamics method. The elastic layer is treated with a moving body-fitted grid, the impacting body with an immersed boundary method, and a discrete-element method is used for the contact-force model. The presence of the elastic layer between the impacting bod- ies may lead to multiple bouncing of them, if the bodies are relatively light, before their interaction is settled and they continue to penetrate together into the water. The present study is motivated by ship slamming in icy waters, and by the effect of ice conditions on conventional free-fall lifeboats.

A Study on Comparison between Growth Indices of Weak Children Groups via Analyzing Bone Age and Body Composition (허약아와 성장지표의 상관성에 대한 연구)

  • Lee, Hye Lim;Han, Jae Kyung;Kim, Yun Hee
    • The Journal of Pediatrics of Korean Medicine
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    • v.28 no.2
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    • pp.1-22
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    • 2014
  • Objectives The purpose of this study is to investigate the relationship between weak children and growth indices. Methods One hundred twenty-six of the first and the second grade elementary school students who didn't have to develop yet their secondary sexual characteristics answered the questionnaire. Their bone age and body composition were measured. Results 1. According to the Weak Children questionnaire analysis, respiratory problem was one of the biggest problems in the weak children group (35.7%), followed by digestive problems (23.0%), psycho-neurological problems (22.2%), neuromotor problems (9.5%), and urogenital problems (8.7%). 2. From the comparison between growth indices of weak children and that of normal children are as follows: 1) The group of children who had problem in their digestive system had lower growth indices than the normal average children group. The growth indices includes mean height, weight, total body water, protein mass, mineral mass, body fat, skeletal muscle mass, body fat percentage, body mass index (BMI), and basal metabolic rate (BMR). 2) The children who had urogenital weakness had lower mean height, RH (Recent Height), RH - MPH {Recent Height(%) - Mid-Parental Height(%)}, RUS (Radius, Ulna and Short bone) score, weight, protein mass, body fat, BMI, and visceral fat than the normal children group. 3. The results of the multiple comparisons of growth indices and weak children groups are as follows: 1) Digestive weak children were the lowest in total body water, protein mass, mineral mass, skeletal muscle mass, and basal metabolic rate. 2) Urogenital weak children were the lowest in height, RH, RH - MPH, RUS score, and weight. Conclusion These results showed that children's growth is strongly correlated to their own growth problems, especially to those children who have digestive and urogenital problems. Therefore, this may be an effective way for children growth treatment in Korean medicine to treat weak symptoms.

Preventing the Musculoskeletal Disorders using Association Rule - Based on Result of Multiple Logistic Regression - (연관규칙을 이용한 근골격계 질환 예방 - 다변량 로지스틱 회귀분석의 결과를 기반으로 -)

  • Park, Seung-Hun;Lee, Seog-Hwan
    • Journal of the Korea Safety Management & Science
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    • v.9 no.4
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    • pp.29-38
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    • 2007
  • We adapted association rules of data mining in order to investigate the relation among the factors of musculoskeletal disorders and proposed the method of preventing the musculoskeletal disorders associated with multiple logistic regression in previous study. This multiple logistic regression was difficult to establish the method of preventing musculoskeletal disorders in case factors can't be managed by worker himself, i.e., age, gender, marital status. In order to solve this problem, we devised association rules of factors of musculoskeletal disorders and proposed the interactive method of preventing the musculoskeletal disorders, by applying association rules with the result of multiple logistic regression in previous study. The result of correlation analysis showed that prevention method of one part also prevents musculoskeletal disorders of other parts of body.

Research of Body Parameters Characteristics from Posture Analysis of Musculoskeletal Problem Patient (근골격계 통증환자의 통증유형과 체형진단을 통한 신체지표 관련성 연구)

  • Park, Jung-Sik;Park, Chang-Hyun;Song, Yun-Kyung
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.10 no.1
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    • pp.47-61
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    • 2015
  • Objectives : The purpose of this study is body parameters characteristics through posture analysis system of musculoskeletal problem patient Methods : Posture analysis system were performed for 164 patients to measure body parameters such as Q-angle, body inclination, neck inclination, PCMT(posterior cervical muscle tension), Knee flexion and posture balance. Statistical analysis using statistical analysis techniques and Pearson correlation coefficients was performed to assess the body parameters obtained by posture analysis system. Results : More than half of people out of 164 reported low back pain, 34.8% of the total was found to have neck pain. There was not a significant difference between genders from the characteristics of gender based body parameters expect for the statistical difference in Q angle, PCMT. There was a significant correlation between low back pain and multiple response status. There was a significant correlations between knee pain and Q angle. Also There was a significant correlations between pelvic pain and posture balance of ankle. Conclusions : Posture analysis system can be used to perform the analysis in place of X-ray measuring body posture and clinical parameters. The results of this study are expected to be the basis for further research on the clinical application of posture analysis system.

Concept Analysis of Cardiac Arrest: Identifying the Critical Attributes and Empirical Indicators (심정지(Cardiac Arrest)에 대한 개념분석: 개념적 속성 및 경험적 지표의 규명)

  • Lee, Kang Im;Oh, Hyun Soo
    • Korean Journal of Adult Nursing
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    • v.26 no.5
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    • pp.573-583
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    • 2014
  • Purpose: Cardiac arrest has multiple characteristics that need to be approached as an integrated method according to the various changes in the body system. This study was performed to develop a useful guideline for early detection of cardiac arrest by revealing the attributes of cardiac arrest through a concept analysis. Methods: This study was conducted according to the Walker and Avant's concept analysis method. Systematic literature review and in-depth interview with nurses who experienced cardiac arrest situation were conducted. Based on the literature reviews and in-depth interviews with nurses, the attributes and the empirical referents of the concept of cardiac arrest were elicited. Results: The definable attributes of cardiac arrest were 1) loss of consciousness, 2) abnormal respiratory condition, 3) abnormal cardiovascular signs. Cardiac arrest was found to occur by several antecedents such as cardiac problem, non-cardiac problem, or general problem, whereas ischemia and re-perfusion injury, which can lead to multiple organ failure and death, were derived as consequences. Conclusion: In this study, the concept analysis eliciting attributes and empirical referents is found to be useful as a guideline for understanding and managing cardiac arrest. Based on these findings, clinical providers are expected to make a precise and rapid decision on cardiac arrest and respond quickly, which may increase survival rate of the patients underwent the arrest event.