• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.627-639
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• 2004

The objective of this research was to evaluate the performance of metal-plate-connected truss joints subjected to cyclic loading conditions that simulated seismic events in the lives of the joints. We also investigated the duration of load factor for these joints. We tested tension splice joints and heel joints from a standard 9.2-m Fink truss constructed from $38-{\times}89-mm$ Douglas-fir lumber: 10 tension splice joints for static condition and for each of 6 cyclic loading conditions (70 joints total) and 10 heel joints for static condition and for each of 3 cyclic loading conditions (40 joints total). We evaluated results by comparing the strengths of the control group (static) with those of the cyclic loading groups. None of the cyclic loading conditions showed any strength degradation; however, there was significant stiffness degradation for both types of joint. The results of this research show that the current duration of load factor of 1.6 for earthquake loading is adequate for these joints.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.145-156
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• 2020

There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90° are more resistant with better ductility.

• Journal of the Korea Safety Management & Science
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• v.4 no.2
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• pp.57-70
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• 2002

Back pain is painful for people at a lower lumber(L4/L5 or L5/S1). It is experienced as a most frequent disaster 70％ of workers have suffered from back-pain. Especially, the occurrence rate of back pain for nurses is very high. Therefore, this study investigates female nurses who worked as a part of a medical cost management team, which mainly deal with the medical insurance in a general hospital at Seoul area. These nurses had different job tasks, which used computers for 50％ of their time, so it can be treated as VDT workers. As a first step of this project, a muscle fatigue was measured for these special VDT workers. First, survey for nurses was conducted to figure out what is a real problem of them. Second, to evaluate an experimental data, a medical cost management team was chosen for subjects. Areas of measurement were 3 places that were the trapezius (TR), the medial deltoid (MD), and the erector spine muscle (ES: L4/L5). These areas are most frequently used, so they were chosen for this study. Measurements were taken before work and after work. From these measurements, it was revealed that a fatigue really comes from their main VDT task excluding natural fatigue after work, so their work environment need to be corrected.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.8
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• pp.713-718
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• 2012

Lumber spine range of motion has been used to measure of physical and functional impairment by various tools from a ruler to 3D kinematic devices. However, pre-existing tools have problems in either movement or accuracy and reliability limitations. Accurate devices are limited by fixed space whereas simple devices are limited in measuring complex movements with less accuracy. In order to solve the location, movement and accuracy limitations at once, we have developed a novice measurement device equipped with accelerometer sensor and gyroscope sensor for getting three-dimensional information of motion. Furthermore, Kalman filter was applied to the algorithm to improve accuracy. In addition, RF wireless communication was added for the user to conveniently check measured data in real time. Finally, the measurement method was improved by considering the movement by a reference point. An experiment was conducted to test the accuracy and reliability of the device by conducting a test-retest reliability test. Further modification will be conducted to used the device in various joints range of motion in clinical settings in the future.

• Journal of Society of Preventive Korean Medicine
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• v.12 no.2
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• pp.27-35
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• 2008

Purpose : The experiments was undertaken to evaluate the effects of Ojeoksan-herbal medicine, in rats' fetus Methods : Female Sprague-Dawley rats were orally administered with the Ojeoksan at dose of 5mg/kg/day for 20 days. Pregnant rats were sacrificed at 20th day of gestation, and observed internal and reproductive organs. Approximately live fetuses in the 20th day of gestation were randomly selected and fixed in 95% ethanol. Results : Neonatal body weight and number of fetus of Ojeoksan group were increased to that of control group. The fetuses of dams treated with Ojeoksan didn't showed external malformation. Vertebral and sternal skeletal variations were observed in Ojeoksan administered group, but compared to the control, those skeletal variations were insignificant. There were no significant changes in number of ribs, cervical, thoracic, lumber, sacral and caudal Conclusion : From these results, it can be concluded that Ojeoksan showed no toxicity effects on number of live fetuses. There were no significant changes in skeletal variations were showed in vertebrate and sternum, Ojeoksan weren't shown significant changes in bone malformation. We need more precise study to investigate the mechanism of early or late resorption by the herbal medicines such as Ojeoksan.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.3
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• pp.93-107
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• 2010

Objectives : The purpose of this study was to assess the efficacy of Chuna and taping treatment in patients with genu varum. Methods : Twenty-seven patients(male:10, female:17) with genu varum were recruited in this study. Chuna treatment at pelvic, and taping treatment at both legs were applied to whole participants. Outcomes were assessed using Q-angle(Quadriceps angle, QA), tibiofemoral angle(TFA), width and length of lesser trochanter(LT), pelvic incidence(PI), pelvic(PT), sacral slope(SS), lumber lordosis angle(LLA), meridian-electromyography(MEMG), Korean western ontario and McMaster universities osteoarthritis index(KWOMAC), and distance of femoral intercondylar distance(ICD). Results : 1. QA, LT width and LT length in radiograph were significantly increased. 2. PI, SS, PT and TFA in radiograph were significantly decreased. 3. The left vastus medialis portion contraction of female was significantly decreased after treatment. 4. The left rectus femoris portion fatigue was significantly decreased after treatment in male subjects. 5. The vastus medialis portion fatigue was significantly decreased after treatment in female subjects. 6. The distance of femoral ICD was significantly decreased. Conclusions : This study showed that Chuna and taping treatment could be used as an effective method for the treatment of genu varum.

• The Korean Journal of Pain
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• v.6 no.1
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• pp.83-95
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• 1993

In out-patient clinic, it seems to be common that most back pain arise from muscular origins rather than from skeletal origins. Most physicians have wished to diagnose lower back pain from the radiologic findings only. From clinical experiences and anatomical studies, I have gotten a different opinion from common sense about backaches. If I met a patient who had lower back pain around the posterior superior iliac crest(P.S.I.C.) area, I would had to search a trigger point in the erector spinae muscles at the level of thoraco-lumber junction rather than at the level of the painful site. It is why that sensory innervation over the posterior superior iliac crest area is the posterior primary branch of T12 spinal nerve running down through the erector spinae muscles. Pain on the iliac crest area is supposedly due to hyperirritability of the sensory nerve distributing to this area. Hyperirritability of the posterior primary branch of $T_{12}$ spinal nerve may be due to the spasm of the longissimus thoracis muscle in the erector spinae muscles at the level of the thoraco-lumbar junction. So finally, I would like to insist that spasmolytic treatment on the muscle at the level of the thoraco-lumbar junction would be better for pain relief around P.S.I.C. than treatment at the painful site only.

• Journal of the Korea Furniture Society
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• v.17 no.1
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• pp.33-46
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• 2006

This study was carried out to investigate a radio-frequency/vacuum (RF/V) drying ability and physical properties of the green boards and the pre-kiln dried boards with 40 mm thickness, and the 70 mm-thick green board of Iroko (Milicia excelsa). The major results were summarized as follows; The drying time from initial moisture content (MC) of 110% to approximate 6% MC for a 40mm-thick green board was 192 hours, and about 200 hours for the 70 mm-thick green board, respectively and so the RF/V drying times were dramatically shortened compared to conventional kiln drying time. The case hardenings at the RF/V drying completion stage test were very negligible, thus represented almost no existence of the residual stress. The checks were very slightly formed on all of the boards during the RF/V drying test, but crook appeared quite severely. During the accelerating test, the water-resistant treated specimens had not experienced any signs of checking occurred, whereas the control boards had encountered very frequent occurrences of end checking and slight surface checking. There were no observations of warping and discoloring regardless of the treatment.

• Journal of the Korea Furniture Society
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• v.20 no.5
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• pp.457-466
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• 2009

This study was carried out to investigate the physical and mechanical properties of 6 hardwoods before and after heat treatment in an effort to produce the high quality industrial lumber product. The results were as follows. Specific gravities of green woods were in range from 0.90 to 1.10. The specific gravities of never treated woods showed higher than those of the heat treated woods. The shrinkage of heat treated woods when green to air & oven dry was significantly low, compared to never treated woods. The compression strengths parallel to grain of heat treated woods showed higher than those of never treated woods. The moduli of rupture (MOR) of never treated and heat treated woods were $176.4N/mm^2{\sim}102.8N/mm^2$ and $100.1N/mm^2{\sim}61.2N/mm^2$ respectively. MORs of heat treated woods showed lower than those of never treated woods. There was no significant change in the modulus of elasticity (MOE) before and after heat treatment.

• Journal of Information Technology Services
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• v.1 no.1
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• pp.67-80
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• 2002

This study aims to explore the ways of reinforcing the competitive edge and substance of company through e-business in furniture industry by presenting the e-business model of furniture industry which faces the opportunity of challenge in the course of industrial restructuring. e-business model can take various types depending on the environment, feature and competitive edge that each company faces. For example, it is general in the fields of manufacturing company to study the model by dividing into Sell Side for sales to the customers, and Buy Side for purchase of raw materials, Integrating both sides. In furniture industry, Sell Side has the feature of giving a priority in the quality and price rather than brand image in the purchase type of consumer. Especially, it shall not be overlooked that majority of furniture is delivered to the consumer indirectly through the construction company. As such, e-business should be promoted in a way to expand the point of contact for consumers, rather than to construct its own point of contact for consumers. The percentage of importation of raw lumber is high and the standardization was insufficient in Buy Side.