• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.431-441
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• 2003

Pregnancy and puerperium are associated with significant changes in pschological and physiologic health status. Back and pelvic pain is common in pregnancy with prevalence figures in the range of $48\%-90\%$. The pain starts during pregnancy and often disappears soon after childbirth. But the prevalence of such pain four to six months post postpartum is report to be $25-40\%$. In $10-15\%$ of the case the pain become chronics, that is persisting for more than three months after childbirth. Low back pain and pelvic pain maybe caused by several factors related to changes that occur naturally during pregnancy. Changes in the center of gravity can create a strain on weight-bearing structures in bone. Pregnancy related hormones, relaxin, create general laxity of collagenous tissue. Another factor found to be a possible primary or contributing cause for law back and hip symptoms are leg length inequality, weight gain and changes in foot function. This article outlines the physiological and biomechanical changes that occur during pregnancy which have been reported to be possible causes of low back and pelvic pain And then, examination, diagnosis, evaluation and treatment of the woman during pregnancy are described. Standard treatment for low back pain and pelvic pain in pregnancy includes education in anatomy and kinesiology, back-strengthening exercise, training of the abdominal muscles and body posture correction. So, most woman during pregnancy require individual consultation and physiotherapist.

• Structural Monitoring and Maintenance
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• v.1 no.3
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• pp.273-292
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• 2014

The effectiveness of a retrofitting method for concrete columns with particular weaknesses is experimentally evaluated and presented in this paper. Structural deficiencies namely the inadequacy of transverse reinforcement and short length of lap splices are very common in columns found in structures built prior to the 1960s and 1970s. Recent earthquakes worldwide have caused severe damages and collapses of these structures. Nevertheless, the importance of improving the load transfer capacity between the deficiently lap-spliced bars is usually underestimated during the strengthening procedures applied in old buildings, though critical for the safety of the residents' lives. Thus, the seismic performance of the enhanced columns is frequently overestimated. The retrofitting approach presented herein involves reinforced concrete jacketing of the column sub-assemblages and welding of the lap-spliced bars to prevent the splice failure and conform to the provisions of modern design Codes. The cyclic lateral loading response of poorly confined original column specimens with insufficient lap splices and the seismic behavior of the retrofitted columns are compared. Test results clearly demonstrate that the retrofitting procedure followed is an effective way of significantly improving the seismic performance of substandard columns found in old buildings.

• Journal of Korea Foundry Society
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• v.30 no.6
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• pp.210-216
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• 2010

The aim of this study is to characterize a thixoextruded 7075 Al wrought alloy bar in terms of its isotropic behavior through the optical microscope, mechanical test and electron back scattered diffraction. It is also discussed of the extrudability improvement for 7075 Al wrought alloy by thixoextrusion, with emphasis on controlling thixoextrusion parameters. Hot extrusion shows that the maximum extrusion pressure depends on their characteristics in terms of flow stress and hot workability. In the contrary, thixoextrusion demonstrates that the maximum extrusion pressure is almost uniform regardless of the experimental parameters, such as initial ram speed, die bearing length and thixoextrusion temperature. The hot extruded microstructures become elongated to extrusion direction, while the thixoextruded microstructures are isotropic and homogeneously distributed due to the existence of liquid phase between solid grains during the process. The grain refinement due to dynamic recrystallization during thixoextrusion has been also occurred. Subsequent recrystallization would lead to the strengthening of mechanical properties, as observed in the study. The important point is that the values of tensile, yield strength and elongation of the thixoextruded bar without plastic deformation are similar to those of the hot extruded bar with severe plastic deformation.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.563-580
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• 2010

Composite beams using bolts to attach steel plates to the side faces of existing reinforced concrete (RC) coupling beams can enhance both their strength and deformability. The behavior of those composite beams differs substantially from the behavior of typical composite beams made up of steel beams and concrete slabs. The former are subjected to longitudinal, vertical and rotational slips, while the latter only involve longitudinal slip. In this study, a mixed analysis method was adopted to develop the fundamental equations for accurate prediction of the load-carrying capacity of steel plate strengthened RC coupling beams. Then, a rigid plastic analysis technique was used to cope with the full composite effect of the bolt group connections. Two theoretical models for the determination of the strength of medium-length plate strengthened coupling beams based on mixed analysis and rigid plastic methods are presented. The strength of the strengthened coupling beams is derived. The vertical and longitudinal slips of the steel plates and the shear strength of the anchor-bolt connection group is considered. The theoretical models are validated by the available experimental results presented in a companion paper. The strength of the specimens predicted from the mixed analysis model is found to be in good agreement with that from the experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.517-520
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• 2004

Concrete Filled steel Tube pipe structure is a rational type of structure that maximizes performance by combining the strong points of steel frame and concrete. In the structure, the confining effect of steel pipes increases the bearing power of infilled concrete and the strengthening of local bucking of steel pipes by infilled concrete increases the bearing power of members. and these result in the reduction of cross-sectional area and high transformation capacity. Moreover. the structure is economically efficient and widely applicable that it is used from super-high buildings to residential, business and apartment buildings. It enables the construction of multi-story buildings with long spans using columns of small cross-sectional area. In case of diaphragm, however, it is difficult to confirm the compactness of the closed inside of steel pipes. The present study examined the properties of super-high strength concrete over 80MPa by comparing it with 40MPa concrete through heat conductivity and length change tests based on a mixture ratio satisfying the mixture goal presented in the guideline for the design and construction of concrete-filled steel pipe structure. and evaluated the performance of super-high strength concrete according to the shape and size of the aperture ratio of diaphragm.

• Smart Structures and Systems
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• v.31 no.5
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• pp.517-529
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• 2023

Using a device composed of two lateral pressure plates (LPPs) and a steel reinforcement bar to apply horizontal pressure on slope surfaces, a newly developed prestress-reinforced embankment (PRE) is proposed, to which can be adopted in strengthening railway subgrades. In this study, an analytical model, which is available of calculating additional confining stress (σ_H) at any point in a PRE, was established based on the theory of elasticity. In addition, to verify the proposed analytical model, three dimensional (3D) finite element analyses were conducted and the feasibility in application was also identified and discussed. In order to study the performance of the PRE, the propagation of σ_H in a PRE was analyzed and discussed based on the analytical model. For the aim of convenience in application, calculation charts were developed in terms of three dimensionless parameters, and they can be used to accurately and efficiently predict the σ_H in a PRE regardless of the embankment slope ratio and LPP side length ratio. Finally, the potential applications of the proposed analytical model were discussed.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.201-210
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• 2021

This study was conducted not only to find out the effect of straight body exercise on neck pain, necks disability and neck length change of turtle neck syndrome patients but also to provide fundamental data for this field in the future. Number of 60 persons were selected by pre-test and divided to 21 persons in straight body exercise group, 19 persons in exercise group and 20 persons in control group(non-exercise group). 5 kinds of straight body exercise were applied in straight body exercise group, 8 kinds of strengthening cervical vertebral exercise were applied in exercise group and no exercise was applied in control group. Neck pain, necks disability index and neck length were measured before and after exercise and 10 weeks later as well. The data were analyzed by SPSS(v18.0). In straight body exercise group and exercise group, neck length, neck pain and necks disability index were significantly decreased after eight weeks of exercise and there was no significant difference in control group. Neck length which was checked every week in straight body exercise group and exercise group was significantly decreased and there were significant differences after 3 weeks.. After 2 weeks of 8 weeks exercise, neck length, neck pain and necks disability were checked again in post test and those results were maintained just like 8 weeks exercise status. As above results, it was more efficient in the straight body exercise group than exercise group and control group to decrease neck pain, necks disability and neck length of turtle neck syndrome patients. Furthermore, after 2 weeks of 8 weeks exercise, the results were maintained just like 8 weeks exercise status. Therefore, the author consider that straight body exercise will be effective exercise for turtle neck syndrome patients, and this study would provide fundamental data for this field in the future.

• Korean Journal of Social Welfare
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• v.54
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• pp.35-64
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• 2003

This study is to explore experience on the inter-organizational linkages for vocational rehabilitation of people with psychiatric disabilities and to find out predictors affecting the linkages. This study used triangulation a way as to combine the advantages of both the qualitative and the quantitative approach. The qualitative approach is based on grounded theory by Strauss & Cobin. The quantitative research used the samples of 122 organizations, and was analyzed by multiple regression & logistic regression. The results are as follows. First, as results of in-depth interview, interviewees perceived linkage experience as 'turning the eyes on the other organization in community', namely 'the pursue of collaboration'. This concept is classified four types: initiative, cooperative, authoritative and passive type. Second, according to Tobin(1986)'s five phase of the closeness of inter-organizational linkages, our linkages were found to be in third phase, "coordination". Finally, predictors of the attempt of having linkages & linkage strengthening were analyzed by logistic regression & multiple regression. 'The experience of professional training on people with psychiatric disabilities' and 'the resource dependency' have statistically significant relation with the attempt to have linkages. 'The length of current service', 'the experience of professional training on people with psychiatric disabilities', and 'recognition about other organizational activities' are significantly related to strengthening linkage. Based on the results of this study, alternatives for promoting inter-organization linkages for vocational rehabilitation of people with psychiatric disabilities were proposed.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.703-710
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• 2010

Reinforced concrete beams of existing structure often encounter insufficient shear problems for various reasons. Application of steel plates is one of widely used methods for shear strengthening of reinforced concrete beams that are insufficient of shear capacity. This study presents test results on strengthening shear deficient RC beams by external bonding of vertical and diagonal slit type steel plates with anchor bolt. Test parameters are width, interval, angle and length of slits with anchor bolt. The purpose was to evaluate the failure modes and shear capacities for RC beams strengthened by various slit type steel plates with anchor bolt. The results showed that the slit type steel plate specimens strengthened by adhesive bonding and bolting failed in shear fracture modes at maximum load. Flexural crack first occurred on the tension face of beam and then inclined cracks occurred on the shear span. Finally, slit type steel plates strengthened by adhesive bonding and fastening bolts managed to delay abrupt debonding and didn't detach fully from main body of RC beam.

• Journal of the Korean Geosynthetics Society
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• v.8 no.3
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• pp.9-16
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• 2009

In generally, ground surface strengthening such as using geotextile is needed to secure trafficability of construction equipment. Several calculation methods for bearing capacity for very soft ground improved by geotextile have been proposed already but they are not established yet. In this paper, elastoplastic finite element analysis is carried out to estimate bearing capacity improvement for very soft ground reinforced by geotextile. In conclusion, by reinforcing with geotextile the bearing capacity improvement of very soft ground is increased with the increase of the settlement after yielding. And it is enough that the length of geotextile is about 3~4 times of the loaded width for the effect to the bearing capacity improvement. Finally, the biggest tensile force of geotextile occurs at an edge of the uniform load.