• Journal of the Korean Society of Physical Medicine
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• v.5 no.2
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• pp.233-243
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• 2010

Purpose : This study aimed to examine the effects of sling exercise therapy on the relief of low back pain and the cross-sectional area change of lumbar muscles by CT analysis for chronic low back pain patients. Methods : Forty-one patients with diagnosis of chronic low back pain was divided sling exercise therapy group(SEG) 19 subjects and conservative physical therapy group(CPG) 22 subjects. we randomized and treated them(subjects) for 12 weeks. As using visual analogue scale(VAS), we evaluated recovery accuracy of pain, and for investigating cross-section area change of lumbar muscles for before and after treatment we used computed tomography(CT). Results : This study were summarized as follows : 1) As treatment period, in each compared testing on VAS of SEG and CPG, the both group was significantly different(p<.05). 2) Compared testing on VAS of between-subject groups(SEG and CPG) were not significantly different(p>.05). 3) At SEG of before and after treatment, in compared testing on cross-section area size of lumbar muscles, All muscles of psoas major, quadratus lumborum, erector spinae and multifidus were significantly different(p<.05). At CPG, psoas major was significantly different(p<.05). But other muscles were not significantly different(p>.05). Conclusion : From this result, both sling exercise therapy and the conservative physical therapy are effect on decrease of pain for chronic low back pain patients. but Increasing of the cross-section area being proportioned with muscular strengthening of low back muscle is noticeable difference in SEG. Therefore, sling exercise therapy have affect both decreasing of pain for chronic low back pain patients and lumbar muscles strengthening.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.2
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• pp.131-139
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• 1988

The thermoacoustic oscillation induced in an air column with variable cross section area is investigated theoretically and experimentally. The onset condition of the oscillation is derived by equating the acoustic power production to the power dissipation. The power production at the heater is predicted by using the efficiency factor obtained by heat transfer analysis for a single wire in a uniform cross flow and considering the interference between heater wires. The power dissipation is estimated by measuring the attenuating coefficient from the pressure decay curve. The theoretical prediction to the onset condition of the oscillation is confirmed experimentally. The effect of the variation of the column cross section area on the onset condition is presented.

• Journal of Acupuncture Research
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• v.30 no.4
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• pp.45-53
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• 2013

Objectives : The purpose of this study was to evaluate the relationship between cross-sectional areas of the paraspinal and psoas muscles with low back pain. Methods : We assessed the cross-sectional area of the psoas and paraspinal muscles at the superior part of L4 level and vertebral body of L4 of 132 patients who were hospitalized with a chief complaint of low back pain at Jaseng Hospital of Korean Medicine from January 2013 to April 2013. After calculating the mean psoas area, we divided the patients into 2 groups by whether the psoas cross section was larger or smaller than the mean, and compared the admission period, verbal numeric rating scale(NRS) of low back pain(LBP), and improvement of verbal NRS of LBP. We also subcategorized the patients into acute and chronic groups according to the duration period, and compared the cross-sectional area of the psoas and paraspinal muscles. Results : Although analyses of the verbal NRS of LBP, and improvement of verbal NRS of LBP between groups with larger and smaller psoas cross section areas showed no significant difference, the admission period was significantly shorter in the group with larger psoas cross section areas. There was no significant difference in analyses of cross section areas in the acute and chronic groups. Of the possible prognostic variables, improvement of verbal NRS of LBP showed no correlation, while the admission period displayed a significant correlation. The cross-sectional area of the psoas and paraspinal muscles divided by the area of the vertebral body of L4 had a significant negative correlation with age. Conclusions : The cross-sectional area of the psoas and paraspinal muscles were correlated with the admission period in LBP patients, and the cross-sectional area of the surrounding muscles divided by the area of the L4 vertebral body was negatively correlated with age.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.57-65
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• 2006

In this study, hydraulic model same as natural channel with junction area and curved reach is constructed, and after that the variation of difference of the water surface elevation at cross section in junction area is analyzed using constructed hydraulic model. In junction area, the variation of maximum water level based on downstream section is more affected in discharge ratio at upstream than downstream. The maximum water level increased as closed to junction and the peak level appeared at just downstream of junction. The slope of water elevation at cross section is affected in section shape and decreased as discharge ratio is reduce. The expressed formulas developed in the channel consist of constant curvature and section shape showed difference of 60% with measured value, but the suggested formula in this study to compute difference of water surface elevation showed difference of 10% with measured value.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.95-112
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• 2009

The river cross section in the input/output data which are needed in the area of river flow analysis is very important factor. The bottom elevation of actual river cross section has to be correctly reflected to obtain correct results when two dimensional flow analysis is conducted for natural river. But to reflect virtually the bottom elevation of river cross section is impossible. The objective of this study is to suggest a method for creating equi-distance river cross section by using both HEC section and ArcView and constructing the finite element mesh. The main channels of Han and Nakdong river were selected and equi-distance river cross sections constructed in this study have shown good agreement with the observed river cross sections. In addition, high quality finite element meshes can be applied to many areas of study such as finite element analysis for water quality and two dimensional flow analysis using the suggested method for equi-distance river cross sections in this study.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.1
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• pp.11-18
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• 1980

In the conventional ship's structures, the stiffeners with asymmetric sections have been widely used, in spite of the disadvantage on the point of strength, compared to those with symmetric sections. So far, the stiffened plating was usually analyzed not considering the geometric unsymmetry characteristics of the section, including only the cross sectional area and moment of inertia. In this paper, the stiffened plating is devided into the strips having a thin-walled open cross section by using the concept of the effective width. The geometric characteristics of the sections are also included. The governing equations are derived, which can be applied to the arbitrary cross section beams, and the symmetric and the asymmetric section beams which have the same cross sectional areas are analyzed by using the finite element method. From that result, we obtain the allowable load of the two sections, and compared them.

• Journal of KSNVE
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• v.9 no.5
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• pp.914-921
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• 1999

There are many theoretical investigations to analyze higher order mode of reactive type single expansion chambers with offset inlet/outlet locations. But the conventional method has the restriction that the ratio between the area of inlet(or outlet) pipe and that of chamber must be natural number. In the paper, a new method was suggested to apply the Kim's method to silencer with circular cross-section. Not only the offset location but also the magnitude of cross-section area of inlet/outlet pipe can be considered by the suggested method. The predictions by this new method also compared with those by the finite element method and Munjal's method in order to verify the accuracy of the suggested method presented here.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1106-1112
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• 2000

In this paper, we present a vision system which measures the cross-section of a hot wire-rod in the steel plant. We developed a mobile vision system capable of accurate measurement, which is strong to vibration and jolt when moving. Our system uses green laser light sources and CCD cameras as a sensor, where laser sheet beams form a cross-section contour on the surface of the hot wire-rod and the reflected light from the wire-rode is imaged on the CCD cameras. We use four lasers and four cameras to obtain the image with the complete cross-section contour without an occlusion region. We also perform camera calibrations to obtain each cameras physical parameters by using a single calibration pattern sheet. In our measuring algorithm, distorted four-camera images are corrected by using the camera calibration information and added to generate an image with the complete cross-section contour of the wire-rod. Then, from this image, the cross-section contour of the wire-rod is extracted by preprocessing and segmentation, and its height, width and area are measured.

• Fire Science and Engineering
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• v.26 no.1
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• pp.23-30
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• 2012

The temperature development of a structural element is dependent on section factor, which is estimated as a ratio of the fire-exposed perimeter to the cross-section area. Hence, with the higher section factor, the faster temperature development of the section os observed. Composite beam member, partially embedded asymmetry H beam, has a good fire resistance to the cross-section. The study was intended to conduct with change with section factor. The experimental result of section type which the Slim Beam Floor is bottom flange reinforced method.

• Structural Engineering and Mechanics
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• v.3 no.6
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• pp.555-567
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• 1995

Design curves have been prepared for prestressed rectangular beam section based on BS 8110, for determining area of steel for any given cross section, for stresses in concrete and steel and for the design moment. The design moment and the area of steel have been expressed in dimensionless form in terms of cross sectional dimensions and the characteristic strength of concrete. The choice and combination of design parameters result in considerably less number of curves as aid for design of rectangular prestressed beam sections, than those reported in CP 110 (Part 3).