• Physical Therapy Korea
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• v.3 no.3
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• pp.59-66
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• 1996

The purpose of this study was to assess the biomechanical effects of corset and back brace for low back pain syndroms patients. The subjects of this study were 69 patients with low back pain syndroms who had been hospitalized or were visited out-patient department of the rehabilitation hospital, college of medicine, Yonsei University, from October 5, 1995 through November 5, 1995. Clinical results and datum were obtained by phone calls and chart reviews of low back pain patients. The results were as follows: 1) Fifty - nine subjects recovered over a good grade (85.6%). 2) The standing workers had a little effect of brace for low back pain. 3) After using a corset and back brace, the test of SLR increased from 36.23% to 72.47%, and the ability of ambulation improved from 40.57% to 85.5%. In conclusion, the biomechanical effects of corset and back brace for low back pain patients were found to be decrease pains and improve posture and ADL function.

• Journal of Korean Physical Therapy Science
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• v.3 no.1
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• pp.843-853
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• 1996

The purpose of this study was to determine whether extension exercise is effective in reducing low back pain. Nine patients with low back pain were randomly assigened to one of two groups-one was an experimental group in which the patient were treated with extension exercise(McKenzie method) and conservative therapy. The other was a control group in which the patients were treated with conservative therapy only. Treatment was performed for a period of ten days during Which we examed each patient three times: the first exam was done at the begining of treatment, the second after fives days, and the third after ten days. We used 'The Oswestry low back pain disability questionnaire'(r=.99) as the examination tool. The results were as follows: 1. Both experimental and control groups showed nonsignificant differences before and after treatment, and the between group difference was also non-significant(P>.05). 2. There was no effective reduction of low back pain by MecKenzie's extension exercise(p>.05). We admit that our study protocol had several shortcomings. If they had been accounted for, the result might have been different. Further study should be done with a better experimental design, a larger sample, and a longer experimental duration.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.14 no.2
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• pp.68-77
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• 2008

Purpose : The purpose of this study was to investigate effects of movement with mobilization(MWM) and stabilization exercise on pain and range of motion of patients with acute low back pain. Methods : The subjects were consisted of 24 patients who had non specific acute low back pain. All subjects randomly assigned to the MWM group and the stabilization exercise group. The MWM group received sustained natural apophyseal glides(SNAGs) with modality treatment and stabilization exercise group received stabilization exercise with modality treatment. The remodified schober test(RST) was used to measure forward flexion and lateral flexion range of motion of lumbar segment. Visual Analogue Scale(VAS) was used to measure subjective pain level of the patients. The Oswestry Low Back Pain Disability Scale was used to measure functional disability level of the patients. Results : The lumbar flexion range of motion of MWM group was significantly increased compared with stabilization exercise group(p<.01). The range of motion of lumbar segment of MWM group was significantly decreased compared with stabilization exercise group(p<.01). The left lateral flexion range of motion of lumbar of MWM group was significantly decreased compared with stabilization exercise group(p<.05). The right lateral flexion range of motion of lumbar of MWM group was significantly decreased compared with stabilization exercise group(p<.05). The VAS of both MWM group and stabilization exercise group was significantly decreased(p<.001). The Oswestry Low Back Pain Disability Scale of stabilization exercise group was significantly increased compared with mobilization group(p<.001). Conclusion : In the result of this study, mobilization with movement and stabilization exercise had significant difference on pain and flexibility of patients with acute low back pain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.954-955
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• 2012

Recently as increasing the use of mobile communication devices the use of mobile readers for recognition tag attached to objects is also increasing. Accordingly, meantime, that gives rise to the vulnerability of RFID systems between reader and tag security issues, as well as security issues between the reader and the back-end server will occur. In this paper between the reader and the back-end server to security vulnerabilities efficient authentication protocol using the hash function is proposed.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.424-430
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• 2001

현대건설(주)는 사업 주관사로서 해외 업체와 대만고속전철 턴키 공사를 2000 년 1 월에 공동으로 수주하였다. 고속전철의 총 연장 길이는 약 326 km 이며, 정거장 10 개소, Depot 및 야적장으로 구성되어 있다. 이번에 수주한 공구는 2 개의 연속된 공구 (C230, C240) 이며, 본 논문은 총 연장 23.6km 인 C230 공구에 대한 설계 과정을 수록하였다. C230 공구는 NATM 터널 (6.2km), Cut-and-Cover 터널 (0.5km), 교량 (7.8km) 및 토공 구간 (9.1km)으로 구성되어 있다. 전 구간의 지반조건은 "매우" 취약한 매질로 구성되어 있으며, 층리나 절리는 거의 발달되어 있지 않다. 따라서 화약발파에 의한 터널 굴착은 기계식 굴착 (Back-hoe Excavation) 방법에 비하여 현실성이 없는 것으로 분석되었다. 취약한 지반에서 계측 결과를 기준으로 굴착 공간을 안전하게 유지할 수 있는 NATM 보강 설계가 현지 암반조건에 가장 이상적인 방법으로 제시되었다. 특히, NAT설계는 대형 아파트 지역과 파쇄대 및 지하수 침투 예상지역을 통과하기 위하여 계측에 의한 Feed-back 과정을 탄력적으로 적용하도록 계획하였다.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.343-350
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• 2006

Medical magnetic stimulator generates strong magnetic field pulses. Clinical applications of the magnetic pulse are the stimulation of nervous system and the contraction of muscle. The unique source of the strong magnetic pulse is a capacitor-inductor resonator and this inductor generates a strong sinusoidal magnetic pulse by discharging the capacitor with high initial voltage. Continuous muscle contraction needs sequential generation of the magnetic pulses. However, to keep the magnitude of sequential pulses identical, an expensive high-voltage power supply have to support voltage drop of the capacitor between the pulses. A protection circuit between the supply and the resonator is necessary to protect the supply from reverse current caused by capacitor voltage reversal. In this paper, a new circuit structure of the magnetic stimulator adopting a low-frequency fly-back switching is proposed. The new circuit supports sequential pulse generation and allows the reverse current without damage. Performance of the new circuit is examined and a low-cost magnetic stimulator for urinary incontinence therapy is being developed using the presented method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1305-1313
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• 2000

In a co-rotating scroll compressor, both scrolls rotate on their fixed axes contrary to the conventional orbiting type scroll machine. This implies fixed locations and directions of the gas pressure force and sealing force. Because the tilting moment is mainly caused by interplay between the resultant force of above forces and bearing reaction force, the variation during one cycle is relatively small. Under real operation, this moment is balanced by the restoring moment created by the reaction between the baseplate and thrust bearing or between the scroll tip and baseplate. If these reactions become too large, greater torque is required due to increased friction in addition to the wear of mating parts. Consequently, appropriate study and minimization of tilting moment is important in the design of scroll machines. In this study, taking into account of the small variation of tilting moment during one cycle, we minimize the moment and thrust bearing reaction force by a properly designed back pressure chamber. As a result, for both the driving and driven scrolls, the tilting moment and the reaction force of thrust bearing can be minimized. And the stability is improved for all cases.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.661-668
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• 2024

Based on the topology of the direct-drive permanent magnet synchronous wind power grid-connected system based on the power electronics full-power converter, the wind turbine model and the grid-side inverter model were studied, and the machine-side rectifier control based on current and speed double closed loops was designed. strategy, as well as a grid-side inverter control strategy based on current and voltage double closed loops, implementing a two-level back-to-back double closed-loop full control strategy. A system simulation model was built using Matlab/Simulink, and the operation of the unit was simulated when the wind speed changed step by step. The grid-connected current with the same phase and good sinusoidal nature of the grid voltage was output. The grid-connected system ran stably and efficiently. The simulation results The validity and rationality of the model, as well as the correctness and feasibility of the control strategy were verified.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.289-297
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• 1997

Work-related low back pain(below LBP) is one of the major cause of morbidity, disability, limitation of activity and economic loss. Therefore the work-related LBP is one of the major issue in the field of industrial safety and health. This study was performed for detecting the risk factors and proposing the effective control programs of work-related LBP. The subjects were male workers employed at the welding and metal factory. The data was collected by self-reported questionnaire, interview and checking abdomen muscular and grasping power for two days on October, 1993. The contents of questionnaire were as follow: the experience of LBP, general characteristics, physical characteristics, employment status, type of work and working environment. The number of cases was 104 with a history of work-related LBP, so the prevalence of work-related LBP was 35.0%, and the number of controls was 140 without any history of LBP. As a result, marital status, educational level, abdomen muscular power, tenure, category of job, satisfaction of job, working posture, satisfaction for table and chair and lifting materials showed a statistical significance between the case and control groups. 284 Lifting jobs were quantified by NIOSH lifting equation method and ergonomic computer modelling methods. There were no significant differences in the action limit and disc compression force between group with LBP and without LBP. But in the lifting frequency and cumulative disc compression force there were significant differences. Therefore work-related LBP should be prevented by the ergonomic and environmental control.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.9-10
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• 2012

Efficient operation of construction equipment has become more and more important in the competitive construction environment. Accurate measurement of performance rate of construction equipment is a critical factor for a construction project planning. However, it might be quite difficult to measure the performance rate due to diverse practical limitations such as continuously variable performance rate of construction equipment, considerable indirect cost, large construction field, and so on. Therefore, the purpose of this paper is to propose an automatic algorithm that measures a performance rate of construction equipment with a multipurpose composite sensor. It is expected that the algorithm compiles database on construction equipment and in advance, facilitates efficient operation of construction equipment.