• 한국안전학회지
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• 제31권5호
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• pp.82-88
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• 2016

The current risk assessment system do not reflect workers' various opinion. However, the worker actually are in the center of work field and are exposed to accidents. In this regard, this study suggests enhanced risk assessment by 'safety circle discussion' on workers' hand. The self-administered surveys on supervisors and workers were done for the effect analysis of the safety circle discussion. According to the question investigation, even though the current risk assessment causes difficulties in preventing accidents by unsafe behaviors, the worker-oriented safety circle discussion establishing measures for risk factors of each work type will be able to prevent accidents more effectively. Also, it can positively contribute to safety health awareness, industrial accident prevention, accurate recognition on risk factors, improving safety facilities/work conditions, workers' compliance to safety health rules. Lastly, most respondents agreed that it is necessary to form organic relationship through circle discussion and deriving safety inspections that workers participate.

• 한국정밀공학회지
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• 제29권4호
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• pp.417-425
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• 2012

This paper presents reference ZMP trajectory generation and implementation for a biped robot via linear inverted dumbbell model (LIDM), which can consider the effect of external momentum on the center of mass (COM) of robot. Based on a reference ZMP trajectory derived by using LIDM, a base trajectory is proposed not only to make the locomotion of robot similar to that of human but also to facilitate its implementation and tuning. In order to realize a dynamic walking using the proposed trajectory, compliance, impedance and ZMP tracking controllers are adopted together. Extensive experiments show that the proposed locomotion of a biped robot is stable and also, similar to that of human. Further researches on balance recovery of a biped robot will be carried out to guarantee its robust locomotion in combination with the proposed trajectory.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.31-37
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• 2010

In proportion to increasing interest in vehicle safety, many country have regulated vehicle safety and performed NCAP(New Car Assessment Program). However vehicles which had good results in these compliance and NCAP frontal crash test have caused problems such as the fork effect and over-riding in real car-to-car accidents. To complement these issues, new frontal crash test modes using new barrier like FWDB and PDB have been developed by EEVC WG15. In this paper, FWDB frontal crash test was performed and the result was compared with the full frontal crash test using the rigid wall in order to comprehend the characteristic of FWDB. The results of FWDB test were compared with one of USNCAP and KNCAP. Using USNCAP data, vehicle performance like deformation and wall force were studied. A comparative study of dummy injuries was made by using KNCAP result. The results showed that vehicle performance of FWDB test like displacement and effective acceleration was similar in spite of absorbing energy of FWDB due to the greater vehicle deformation of rigid wall test. In FWDB test, driver dummy head bottomed out but most of injuries were superior to the injury of rigid wall test.

• Steel and Composite Structures
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• 제2권3호
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• pp.209-222
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• 2002

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.

• 한국안전학회지
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• 제25권4호
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• pp.76-83
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• 2010

As one of crucial industries, the service industry occupies a large part of economy in Korea poor in natural resources. However, prevention of industrial disasters has been promoted mainly in manufacturing and construction industries where the frequencies of such disasters and victims are high. Research on the evaluation of workplace safety climate has been conducted centering on traditional industries like manufacturing and construction, and few studies have been made for service businesses. The objective of this study was to evaluate workplace safety climate perceived in the field by workers engaged in service businesses and to contribute to the establishment of industrial safety and health policies in consideration of the characteristics of each business category. Using research variables safety knowledge, safety attitude, safety motivation, safety participation, safety compliance, and safeness of work environment, we evaluated comprehensive workplace safety climate based on the causal relations among the variables. In the results of analyzing data from a questionnaire survey of service business employees, statistically significant effect relations among the variables were identified, and the fitness of the model with approved reliability and validity was verified.

• 한국항공우주학회지
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• 제42권11호
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• pp.911-918
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• 2014

본 논문에서는 응집영역 모델링 방법에 의한 균열전파 해석에서 발생하는 연성추가문제의 효과적인 해결방법으로 사용자 부프로그램 UMPC를 이용한 응집요소의 선택적 활성화 기법을 연구 하였다. 먼저 균열의 발생 및 전파가 예상되는 지역의 일반요소들 사이에 응집요소를 삽입하고 응집요소를 구성하는 절점에 다중점 구속조건을 적용함으로써 응집 요소를 비활성화 시킨 상태로 해석을 시작한 후, 해석 도중에 특정 조건을 만족하는 절점들에 대해서만 다중점 구속조건을 해제하여 응집요소를 선택적으로 활성화하는 전략을 사용하였다. 응집요소의 초기강성 및 다중점 구속조건 해제 지표가 균열전파 거동 및 계산시간에 미치는 영향을 체계적으로 조사하였다.

• 한국정보통신학회논문지
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• 제4권2호
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• pp.365-370
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• 2000

본 논문에서는 접지면의 크기가 안테나의 성능에 미치는 영향을 분석하기 위하여 기존의 프린트형 안테나의 특성 개선 요구에 부응한 안테나를 설계ㆍ제작하여 프린트형 안테나의 접지면의 크기에 따른 특성을 측정, 분석하여 최적의 접지면 크기를 산출하였다. 폴디드 안테나의 특성에 미치는 접지면 효과를 알아보기 위해 동박판을 잘라 기존의 폴디드 슬롯 안테나의 접지면을 확장시켰을 때 임피던스 및 방사 특성의 변화를 조사한 결과 임피던스 특성에는 별로 영향을 주지 않았으나, 방사 특성에는 많은 영향을 미치고 있음을 확인 할 수 있었다. 접지면의 크기를 고려한 엄격한 설계를 위해서는 복잡한 과정을 거쳐야 하지만, 접지면의 효과를 무시할 수 있는 적당한 크기를 산정하여 제작한다면 좀더 간단하게 안테나를 제작할 수 있을 것이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1294-1297
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• 2003

With the development of medical field, many kinds of operations have been performed on human articulation. Arthroscopic surgery, which has Irrigation Pumping System for security of operator vision and washing spaces of operation, has been used for more merits than others. In this paper, it is presented that the research on a reliable control algorithm of the pumping system instrument for arthroscopic surgery. Before clinical operation, the flexible artificial articulation model is used for realizing the model the most same as human's and the algorithm has been exploited for it. This system is considered of the following; limited sensing point, dynamic effect by compliance, time delay by fluid flow and so on. The system is composed with a pressure controller, a regulator for keeping air pressure, an airtight tank that can have distilled water packs, artificial articulation and a measuring system, and has controlled by the feedback of pressure sensor on the artificial articulation. Also the system has applied to Smith Predictor for time delay and the parameter estimation method for the most suitable system with both the experiment data and modeling. In this paper, the pressure error that is between an air pressure tank and an artificial articulation was measured so that the system could be presumed and then the controller had developed for performing State-Feedback. Finally, the controller with a real microprocessor has realized. The confidence of system can be proved by applying this control algorithm to an artificial articulation experiment material.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2771-2776
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• 2000

In this work, the effect of surface treatment of prepreg on the mode I fracture behavior was studied. Unidirectional (0-deg) double cantilever beam (DCB) specimens were used for fracture tests. Two groups of DCB specimens were made: the first group was made of prepregs surface-treated by Ar(sup)+ ion beam under oxygen environment and the second group was made of regular prepregs. For both groups, fracture resistance curve (R-curve) was determined and compared to each other, Results showed that resistance behavior of the first group is better than that of the second group. That is, mode I fracture toughness, G(sub)Ic of the first group is 24% larger than that of the second group. SEM examination shows that the improvement of G(sub)Ic is due to the increase of interfacial strength between plies.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.719-726
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• 2001

Transdermal drug delivery offers various advantages over conventional drug delivery systems, such as avoidance gastrointestinal degradation and hepatic first-pass effect. encourages patient compliance. and possible sustained release of drugs. However, transdermal transport of drugs is low permeability of the stratum corneum, the superficial layer of the skin. Many physicochemical and biological factors influencing transdermal transport is described together with the corresponding experimental and clinical results. Phonophoresis is medical treatment with drugs introduced into the skin by ultrasound energy. Enhanced drug penetration is through to result from the biophysical alterations of skin structure by ultrasound waves. The frequency used for phonophoresis is usually from 20 kHz to 15MHz. Phonophoresis can be categorized in to three ranges: low-frequency range(below 1 MHz). therapeutic frequency range(1 to 3MHz), and high-frequency range(above 3 MHz). The depth of penetration of ultrasound into skin is inversely proportional to the frequency. Cavitation may cause mechanical stress. temperature elevation, or enhanced chemical reactivity causing drug transport. One theory is that ultrasound affects the permeation of the stratum corneum lipid structure as the limiting step in permeating through the skin. The range of indications for phonophoresis is wide. Aspecific classification of the range of indications is obtained by classification of pathological conditions. The continuous research is needed for many interesting issucs of phonophoretic transdermal delivory in new future.