• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.385-397
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• 2002

Objectives: This study was to investigate the experience and a Point prevalence rate and factors related with Low Back Pain (LBP) in instructors of drive institute. Methods: Questionnaires were completed by 174 instructors who worked at 13 drive institutes in 4 small cities from June 2002. The information was used to estimate odds ratio (OR) and 95$\%$ confidence intervals (CI) for factors relation to LBP. A retrospective study design was used. Results: The experience rate for LBP was 57.2$\%$, 43.4$\%$ in one year interval prevalence, 42.2$\%$ in 6 months interval prevalence, and 35.8$\%$ in a point prevalence rate. Factor significantly associated with LBP experience by logistic regression was labour hour (p=0.0034), subjects who worked for long hours a day were higher than those who did not (OR=3.8, 95$\%$ CI 1.4-5.6). Conclusions: In conclusion, labour hour was significantly associated with LBP experience.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.331-338
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• 2000

Objectives: The objective of this study was to investigate the experience and point prevalence rate and factors related with Low Back Pain (LBP) in bin drivers. Methods: Questionnaires were completed by 200 drivers at 2 bus companies in Andong city in October.2000. The information was used to estimate odds ratio (OR) and $99\%$ confidence intervals (CI) for factors relation to LBP. A cross-section study design was used. Results: The experience rate for LBP was $53.5\%$, point prevalence rate was $31.5\%$. Variables significantly associated with LBP experience were employ duration and stress related occupation. The higher subjects had experienced stress. the higher experience for LBP was (OR=2.9, $95\%$ Cl 1.2-7.2). The longer subjects had employ duration in bus company, the higher experience far LBP was (OR=1.3, $95\%$ Cl 1.2-7.2). Significant factors relation to a week point prevalence far LBP were obesity and employ duration. LBP increased as weight increased (OR=4.1, Cl 1.6-10.7). The longer subjects has employ duration at bus company, the higher LBP is (OR=1.4. $95\%$ Cl 1.6-2.9). Conclusions: Results from this study indicated that a statistically significant factor relation to LBP was stress related occupation. employ duration, and obesity.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.242-242
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• 2010

SiO2박막을 이온 감지막으로 이용한 pH농도센서를 제작하였다. 현재 많은 연구중인 pH센서, pH-ISFET(pH-Ion Sensitive Field Effect Transistor)는 용액과 기준전극간의 전기화학적 변위차를 이용하여 pH를 센싱한다. pH-ISFET는 기존 CMOS공정을 그대로 이용할 수 있고, 이온감지막의 변화만으로 다양한 센서를 제작할 수 있어 최근 많은 연구가 진행 중이다. 하지만 FET를 제작하기 위한 공정의 복잡성과 용액의 전위를 정해주고 FET에 바이어스를 인가해줄 기준전극이 반드시 필요하다는 제한성이 있다. 따라서 본 연구에서는 SOI 기판을 이용하여 간단한 구조의 pH센서를 제작하였다. 센서는 (100)결정면을 가지는 p-타입 SOI(Silicon On Insulator)기판을 사용하였으며 포토리소그래피 공정을 이용하여 back-gated MOSFET구조로 제작하였다. 이온감지막으로 사용할 SiO2박막은 RF 스퍼터링을 이용하여 $100{\AA}$ 증착하였다. 바이어스는 기존 pH-ISFET와는 다르게 기준전극 대신 기판을 backgate로 사용하여 FET에 바이어스를 인가해 주었다. pH 용액 주입을 위해 PDMS재질의 챔버를 제작하고 실리콘글루를 이용하여 센서에 부착하였다. pH12부터 pH4까지 단계적으로 누적시키며 챔버에 주입하였고, pH에 따른 드레인전류의 변화를 관찰하였다. pH용액을 챔버에 주입시, pH농도에 따라 제작된 센서의 문턱전압이 오른쪽으로 이동하는 결과를 관찰할 수 있었다. 결과적으로, 구조가 간단한 pseudo MOSFET을 이용하여 pH센서의 적용가능성을 확인하였으며 SiO2박막 역시 본 pH센서의 이온감지막의 역할과 센서의 안정성을 향상시킬 수 있다는 점을 확인하였다.

• The Journal of Korean Physical Therapy
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• v.29 no.6
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• pp.307-315
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• 2017

Purpose: The purpose of this study was to investigate the effects of kinesio taping on lumbar flexibility onto erector spinae and sacroiliac joint. Methods: Sixty healthy adults (male=36, female=24) participated in this study and were randomly assigned to the experimental group that received kinesio taping onto erector spinae and sacroiliac joint (n=30) or the control group that received X-letter placebo taping onto them (n=30). Lumbar flexibility (flexion, extension, lateral flexion, and rotation) was measured using back range-of-motion instrument (BROM) II before and after taping. Results: In the change of lumbar flexibility after taping in the experimental group, there were statistically significant difference in flexion, lateral flexion, and rotation (p<0.05), but there was no significant difference in extension. There was no significant difference in the change of lumbar flexibility after taping in the control group. Conclusion: In conclusion, kinesio taping onto erector spinae and sacroiliac joint improved the joint function. Kinesio taping may reduce the muscle tension and facilitate the circulation of tissue fluid. In light of these results, it is thought that the application of kinesio taping had influence on an increase in lumbar flexibility. Therefore, kinesio taping will be able to be used as the method of the prevention of pain and the treatment in the lumbar region.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.391-394
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• 2008

Global warming and air pollution have increased the amount $CO_2$ in the atmosphere. In order to decrease the amount of $CO_2$, lots of researches are conducted toward using Hydrogen energy. Because of its high efficiency energy level and environmental friendly features, many companies have researched on developing hydrogen engine system and distributed generation system. Especially, the focus of this research provides the operation method of linear generator for hydrogen fuel combustion linear engine. During an ignition, linear generator is operated by motor to create the initial condition of engine combustion. Once the engine combustion is stabilized, the generator supplies electric power to grid. In order to stabilize the engine, linear generator is required to control mover frequency, direction, and force; Hence the PCS(Power Conversion System) place three H-bridge type inverter stacks in parallel to control phase current independently. As well, by using Back-to-Back method, it can receive electric power from both end.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.5
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• pp.681-691
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• 2008

Taking into consideration both the inconveniences reported with current working uniform for the aircraft mechanics and the subjects' requirements mentioned in preceded survey, the researchers designed an ergonomic sample garments with improved motional flexibility and comfort. To improve motional flexibility, extra folds were added to the back of the garments to allow for ease of motion of limbs, so that the material would not be drawn up by the motion of the arms. Darts were added to the elbow, hip, the knee. Furthermore, by increasing the length of the waist centerline, the hip region would not be drawn up. For improved comfort, $CoolMax^{(R)}$ was used as lining material for the armpit and back region to discharge swear promptly. Subjects and panels were asked to evaluate the sample garment that followed an ergonomic design and pattern. According to the results, the sample garment was evaluated more highly than the existing working uniform in appearance and motional flexibility. The field tests by three aircraft mechanics working in the Office of Forestry were also demonstrated that the sample garment was advanced in terms of motional flexibility and comfort.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.3
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• pp.71-82
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• 2009

As a solution to spectrum under-utilization problem, Cognitive radio (CR) introduces a dynamic spectrum access technology. In the area, one of the most important problems is how secondary users (SUs) should choose between the available channels, which means how to achieve load balancing between channels. We consider spectrum load balancing problem for CR system in frequency domain and especially in time domain. Our objective is to balance the load among the channels and balance the occupied time length of slots for a fixed channel dynamically in order to obtain a user-optimal solution. In frequency domain, we refer to Dynamic Noncooperative Scheme with Communication (DNCOOPC) used in distributed system and a distributed Dynamic Spectrum Load Balancing algorithm (DSLB) is formed based on DNCOOPC. In time domain, Spectrum Load Balancing method with QoS support is proposed based on Dynamic Feed Back theory and Hash Table (SLBDH). The performance of DSLB and SLBDH are evaluated. In frequency domain, DSLB is more efficient compared with existing Compare_And_Balance (CAB) algorithm and gets more throughput compared with Spectrum Load Balancing (SLB) algorithm. Also, DSLB is a fair scheme for all devices. In time domain, SLBDH is an efficient and precise solution compared with Spectrum Load Smoothing (SLS) method.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.926-931
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• 2012

Since robot industry growing, the machine that could move with multi-DOF has been studied in many industrial fields. Spherical motor is one of the multi-DOF machine that doesn't need gear for multi-DOF motion. Unlike conventional motor, spherical motor can not only rotate on the shaft axis (rotating motion), but tilt the shaft with 2-DOF motion (positioning motion). In the typical type of spherical motor, one coil took part in positioning motion and rotating motion at the same time. As the result, the control algorithm was complex. To solve this problem, this study proposed a novel type of coil on the stator. The coils were separated for positioning motion and rotating motion. Thus the linkage flux of rotating coil didn't be affected the positioning angle. In this paper, comparing the back-EMF of typical and novel type was conducted and the driving experiment was carried out as the positioning angle. From the experiment result, the performance of proposed spherical motor could be verified.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.282-283
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• 2017

본 논문은 (주)효성 중공업연구소에서 국책과제를 통해 자체 개발한 MMC(Modular Multi-level Converter) type ${\pm}12kV$ 25MVA HVDC 시스템에 대하여 실증단지 구축 및 commissioning test에 대한 소개를 한다. 제주에 구축된 HVDC 실증단지는 국내 유일의 MMC type 전압형 HVDC 시스템이며 11-레벨의 AC 출력 전압을 형성하는 2개의 컨버터가 Back-to-Back 형태로 구성되어 있다. 각 컨버터의 AC 출력단은 각각 계통과 풍력발전단지에 연계되어 풍력발전단지에서 생산된 전력을 계통으로 전송하는 역할을 한다. 주요 AC/DC Yard 기기들로는 AC 고조파 필터, 밸브리액터, DC 리액터, 변압기, CGIS등이 있다. HVDC 의 commissioning test를 위해 IEEE, IEC, Cigre TB 등의 문서들을 종합 분석하여 당사의 시스템에 알맞은 시험절차서와 검증항목을 준비하였다. 본 논문에서는 당사에서 준비한 시험절차서 및 검증항목에 대하여 소개하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.371-377
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• 2006

Cold cathode fluorescent lamps (CCFL) show complex characteristics, which make it difficult to drive them in parallel. In this paper, a multi-lamp driving scheme is proposed to drive multiple lamps for LCD back light to reduce output current unbalance. This propose system is composed of parallel CCFLs, series transformers. The driving system adopts only one backlight inverter to drive multi cold cathode fluorescent lamps (CCFL). Moreover the circuit introduces a multi-lamp driving transformer to reduce lamp-current imbalance. The validity of the proposed scheme is confirmed by the simulated and experimental results.