• Title/Summary/Keyword: cross sectional study

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Improvement of Cross Sectional Distance Measurement Method of 3D Human Body (3차원 인체 형상의 공극거리 측정 방법 효율성 향상을 위한 연구)

  • Kim, Min-Kyoung;Nam, Yun-Ja;Han, Hyun-Sook;Choi, Young-Lim
    • Fashion & Textile Research Journal
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    • v.13 no.6
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    • pp.966-971
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    • 2011
  • This study is designed to develop programs that analyze the distance of clothes from human skin and cross-sectional body figures based on 3D human body scan data, and to verify accuracy and efficiency of the program so that it can be used for clothing fit evaluation and 3D human body research. The auto cross-sectional imaging program was developed by using Visual C++ and OpenGL, and the 3D human body scan data were adopted to measure the space between skin and clothing. The space measurements were obtained by two widely used programs, RapidForm and AutoCAD, and a program devised by the researchers of this study. Measuring time and space measurements from different programs were compared in order to verify accuracy and efficiency of the newly-devised program. As a result, no significant difference was found in the measurements. However, the required time to measure one cross section was different within the significance level of 0.05, and the differences become more remarkable as the number of measuring and the angle of space between skin and clothing increase. Therefore, the program developed by this study is expected to be useful for research on body shapes and fit evaluation based on 3D human body scan data in the fashion field.

A study on cross sectional characteristics and available area for using the lower space in TBM road tunnels (TBM 도로터널의 단면특성 및 하부공간 활용을 위한 유효면적 검토)

  • Kim, Hyun-Soo;Kim, Hong-Moon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.14 no.2
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    • pp.141-157
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    • 2012
  • For the application TBM tunneling method, Both tunnel design standard and case study designed & constructed in domestic and foreign have been conducted. According to the study, the number of lane and inner shape (single or duplex) vary depending on the volume of traffic. Also extra space located in the top and bottom of tunnel is used for a multipurpose such as ventilation, disaster prevention, maintenance and administration. To find area ratio according to the components of road TBM tunnel, a standard section was considered as a two-lane road. Then, the analysis of area ratio of this section which consists of components for clearance, extra space in upper and lower tunnel was carried on two widths of shoulder. In addition, after a structural analysis, a thickness requirement of lower slab which is essential for road tunnel was derived on a few supporting types. Through correlation analysis, the ranges of available cross-sectional area between slab thickness and lower extra space of the tunnel was presented.

A Study on tile Cross Section Optimization of P.C Box-Girder Bridge (P.C 박스거더교의 횡단면 최적설계에 관한 연구)

  • 방명석;김일곤;조현준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1990.10a
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    • pp.101-104
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    • 1990
  • The program which could determine cross-sectional dimensions of the box girder bridge at tile stage of preliminary design was developed using the optimal technique in this study. It could minimize the cost and time required in the design of box girder bridges and the construction with the prestressed precast segmental method. Objective cost function consisted of four independent variables such as widths and depth of the cross-section. The Nelder-Mead method was used to solve the nonconstrained nonlinear problem like this.

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A cross - sectional analysis of scientific and technological performance for the railroad R&D (철도 R&D의 과학기술적 성과에 대한 횡단면 분석)

  • Park, Man-Soo;Bang, Yoon-Seok;Kwon, Yong-Jang;Moon, Dae-Seop;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1582-1590
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    • 2011
  • An analysis of the railroad industry for R&D investments has been insufficient whereas there are lots of analysis of accumulation of technology, economic performances and ripple effects for macroscopic view and other industry of R&D investments. This study decided intellectual rights, patent, and paper as common indicators of scientific and technological performances for setting up performance targets through surveying and analysis of preceding study and verified a appropriateness of scientific and technological performances for railroad R&D 11 projects which were successfully finished. Preceding study has been set up performance targets by research investments as input, but this study made a performance target by model through a cross-sectional and residual analysis of performances of railroad R&D 11 Projects in applying research investments, capital investments, inner labor cost and inner labor cost per man and research time as inputs, and verified a validity and a empirical analysis through analysis of other project.

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A Study on fluvial Phenomena in the Bended Alluvial Rivers (만곡유로에서의 하상변동에 관한 연구)

  • 고재웅
    • Water for future
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    • v.8 no.2
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    • pp.75-80
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    • 1975
  • The fluvial phenomena in the bended natural river course are studied experimentally. Some theoretical and empirical conclusions were derived in prior to this study by some authors but the limitation of applicability of those results are not clearly known because of the sensitibitys of the flow regime in the reach. The main objective of this study is directed to evaluate the mechanism of sedimentation and the cross sectional changes in the equilibrium status. the most governing factor influenced to the cross sectional changes in the bended reach is the occurance of spiral flow. In this study, the streamlines and velocity distributions are checked at given interval by the hydraulic model to find out the place where spiral flow are existing under the various flow magnitudes.

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The study of correlation between forward head posture and shoulder pain: A STROBE-compliant cross-sectional study

  • Kim, Hyun-Joong;Lee, DongJin
    • Physical Therapy Rehabilitation Science
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    • v.10 no.3
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    • pp.251-256
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    • 2021
  • Objective: The forward head posture (FHP) is strongly related to the rounded shoulder posture (RSP), which is associated with shoulder pain. Design: Observational cross sectional study design Methods: A total of 37 were enrolled in the study, 22 individuals with FHP(experimental group) and 15 healthy adults(control group). Correlation with differences between groups was analysed through craniovertebral angle (CVA) representing FHP for both groups, neck disability index (NDI) indicating neck pain, disability of the arm, shoulder and hand (DASH) indicating shoulder pain. Results: There was a significant difference in the results of CVA, NDI, and DASH in FHP and healthy adults (p<0.05). Significant correlations were found between DASH and CVA in FHP participants (r = -0.656, p = 0.001). Also, in the regression analysis results of DASH and CVA, the regression model was found to be suitable and the variation in DASH could be explained by 43% (F = 15.118, p = 0.001). Conclusions: Shoulder pain and neck discomfort are potentially related, and an increase in shoulder pain can increase FHP.

A numerical analysis on the performance of buckling restrained braces at fire-study of the gap filler effect

  • Talebi, Elnaz;Tahir, Mahmood Md.;Zahmatkesh, Farshad;Kueh, Ahmad B.H.
    • Steel and Composite Structures
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    • v.19 no.3
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    • pp.661-678
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    • 2015
  • Buckling Restrained Braces (BRB) have been widely used in the construction industry as they utilize the most desirable properties of both constituent materials, i.e., steel and concrete. They present excellent structural qualities such as high load bearing capacity, ductility, energy-absorption capability and good structural fire behaviour. The effects of size and type of filler material in the existed gap at the steel core-concrete interface as well as the element's cross sectional shape, on BRB's fire resistance capacity was investigated in this paper. A nonlinear sequentially-coupled thermal-stress three-dimensional model was presented and validated by experimental results. Variation of the samples was described by three groups containing, the steel cores with the same cross section areas and equal yield strength but different materials (metal and concrete) and sizes for the gap. Responses in terms of temperature distribution, critical temperature, heating elapsed time and contraction level of BRB element were examined. The study showed that the superior fire performance of BRB was obtained by altering the filler material in the gap from metal to concrete as well as by increasing the size of the gap. Also, cylindrical BRB performed better under fire conditions compared to the rectangular cross section.

The Evaluation Model of Aggregate Distribution for Lightweight Concrete Using Image Analysis Method (이미지 분석을 이용한 경량골재 콘크리트의 골재분포 판정기법 개발)

  • Ji, Suk-Won
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.10
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    • pp.11-18
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    • 2018
  • In this study, the cross-sectional image has been acquired to evaluate the aggregate distribution affecting quality of lightweight aggregate concrete, and through the binarization method, the study is to calculate the aggregate area of upper and lower sections to develop the method to assess the aggregate distribution of concrete. The acquisition of cross-section image of concrete for the above was available from the cross-sectional photography of cleavage tension of a normal test specimen, and an easily accessible and convenient image analysis software was used for image analysis. As a result, through such image analyses, the proportion of aggregate distribution of upper and lower sections of the test specien could be calculated, and the proportion of aggregate area U/L value of the upper and lower regions of concrete cross-section was calculated, revealing that it could be used as the comprehensive index of aggregate distribution. Moreover, through such method, relatively easy image acquisition methods and analytic methods have been proposed, and this indicated that the development of modeling to assess aggregate distribution quantitatively is available. Based on these methods, it is expected that the extraction of fundamental data to reconsider the connectivity with processes in concrete will be available through quality assessment of quantitative concrete.

Changes in Cross-sectional Area of Lumbar Muscle in Patients with Chronic Back Pain (만성요통환자의 요부근육 단면적의 변화)

  • Kim, Seong-Yeol
    • The Journal of Korean Physical Therapy
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    • v.22 no.5
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    • pp.39-47
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    • 2010
  • Purpose: The purpose of this study was to characterize changes in back muscles in patients with chronic back pain. Accordingly, we studied 154 patients with chronic low back pain with regard to area, aspect and triggering position of the pain. We also determined muscle atrophy in painful areas. Methods: Subjects were questioned about pain and a pain provoking test was done. On Magnetic Resonance Imaging (MRI), we measured cross sections of the multifidus, erector spinae, iliopsoas and quadratus lumborum muscles at each spinal level. Results: Muscles in painful regions (multifidus and erector spinae muscles) decreased in area significantly more than nonpainful regions, and showed a significant difference (p<0.05) at levels L3, L4, and L5. Painful regions of the iliopsoas and quadratus lumborum did not change significantly more than non-painful regionsexcept at L5 (p<0.05). The group that had unilateral low back pain showed a significant decrease in cross section compared to the group that had central or bilateral pain (p<0.05). Conclusion: Chronic low back pain causes variable decreases in cross-sectional areas of some but not all back muscles, and at some but not all spinal levels.

Three dimensional flow analysis within a profile extrusion die by using control volume finite-element method

  • Kim, Jongman;Youn, Jae-Ryoun;Hyun, Jae-Chun
    • Korea-Australia Rheology Journal
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    • v.13 no.2
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    • pp.97-106
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    • 2001
  • Three-dimensional flow analysis was performed by using the control volume finite-element method for design of a profile extrusion die. Because polymer melt behavior is complicated and cross-sectional shape of the profile extrusion die is changing continuously, the fluid flow within the die must be analyzed three-dimensionally. A commercially available polypropylene is used for theoretical and experimental investigations. Material properties are assumed to be constant except for the viscosity. The 5-constant modified Cross model is used for the numerical analysis. A test problem is examined in order to verify the accuracy of the numerical method. Simulations are performed for conditions of three different screw speeds and three different die temperatures. Predicted pressure distribution is compared with the experimental measurements and the results of the previous two-dimensional study. The computational results obtained by using three dimensional CVFEM agree with the experimental measurements and are more accurate than those obtained by using the two-dimensional cross-sectional method. The velocity profiles and the temperature distributions within several cross-sections of the die are given as contour plots.

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