• 한국융합학회논문지
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• 제12권8호
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• pp.215-228
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• 2021

본 연구의 목적은 질적연구방법을 이용하여 미국 고령층의 복지기술 수용성에 영향을 미치는 사회문화적 요인을 추출하고 각 요인과 복지기술 수용성간의 연관성을 분석하여 향후 고령자의 삶의 잘향상을 위한 사회문화적 기반복지기술 수용성 증진방안을 도출하는데 기여하기 위함이다. 10명의 노인분야 전문가와 심층인터뷰를 통해 수집한 자료를 두 차례에 걸친 개방형 코딩 프로세스로 결과를 도출하였다. 자료분석 결과 7개의 주 코드와 주 코드에 중첩된 22개의 2차 코드 등 총 29개의 코드를 통해 사회문화적 요인을 추출하였다. 분석결과 개인주의, 가족중심문화, 실용주의, 저맥락 문화, 프라이버시, 재미추구와 수평적문화 등이 미국 고령층의 복지기술수용에 영향을 미치는 사회문화적 요인으로 나타났다. 이 연구결과는 고령층의 복지 기술사용의도에 영향을 미칠 수 있는 국가별 문화적 차이를 정의하고, 각 요인과 복지기술 수용성간의 관계를 분석하기 위한 설문조사 개발에 기여할 것이다. 이를 위해서는 향후 연구에는 한 국가 또는 국가 간 사회문화적 차이를 설명하는 척도개발이 필요하다.

• 암석학회지
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• 제26권1호
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• pp.93-98
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• 2017

본 논문에서는 화산 분화 시 분출되는 용암류의 피복 범위와 용암류의 두께를 모의하기 위한 용암류 시뮬레이션 프로그램을 구현한다. 지도 정보를 DEM과 같이 일정한 면적마다 관측된 값을 가진 '셀'로 나타내고 셀룰러 오토마타 모델을 적용한 용암류 모의 알고리즘을 수행하여 용암류의 흐름에 대해서 모의한다. 용암류의 정량적인 데이터를 얻기 위해 용암류의 유체 특성을 빙햄 소성유체(Bingham plastic fluid)로 정의하고, 유도된 식을 셀룰러 오토마타의 규칙에 사용한다. 프로그램에 대한 검증을 위해 USGS에서 제공하는 30m 해상도 DEM을 이용하였으며, Hawaii의 푸우오오 분화구(Pu'u'O'o crater) 지역에서 2016년 5월 24일에 발생한 용암류에 대해 실제로 용암류가 흐른 흔적과 시뮬레이션의 모의 결과를 비교하였다.

• 한국정밀공학회지
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• 제19권11호
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• pp.37-45
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• 2002

This paper presents the field-dependent Bingham characteristics and damping force control of an electro-rheological (ER) fluid under squeeze mode operation. The squeeze force of the ER fluid due to the imposed electric field is analyzed and an appropriate size of the disk-type electrode is devised. On the basis of the theoretical model of the ER fluid under squeeze mode operation, the yield stress and response speed of the ER fluid are distilled from the time responses of squeeze force to the step electric potentials. Measured squeeze forces under various excitation conditions are compared with the predicted ones from Bingham model and time constant obtained at the transient response test. In addition, the controllability of the field-dependent damping force of the ER fluid under squeeze mode is experimentally demonstrated by implementing simple PID controller.

• 한국자동차공학회논문집
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• 제2권3호
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• pp.62-74
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• 1994

This paper addresses on the model synthesis and performance analysis of an engine mount featuring electro-rheological(ER) fluids which undergo a phase change when subjected to electric fields. A novel type of ER fluid-filled engine mount is devised and its hydraulic model is constructed. An equivalent mechanical model is subsequently obtained from the governing equation of the hydraulic model. The model parameters associated with the ER fluids are distilled from experimental investigations on the Bingham properties of the fluids. The distilled data are then incorporated into the governing model to undertake feasible work through computer simulations,. It is shown that the proposed engine mount has an inherent capability of controlling both the damping force and the resonance frequency. Other superior performance characteristics accrued from the proposed methodology are also evaluated.

• Tribology and Lubricants
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• 제25권3호
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• pp.176-181
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• 2009

Aminated polyacrylonitrile as the new organic disperse phases of the anhydrous ER fluid has been synthesized and ER effect of the suspension composed of aminated polyacrylonitrile in silicone oil investigated. The suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.6 power on theelectric field. The current density and the conductivity of the of aminated polyacrylonitrile suspension increase with the electric field intensity and moreover the conductivity of the suspension is about 8 order of magnitude higher than that of the silicone oil. On the basis of the the results, aminated polyacrylonitrile suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amine polar group of the aminated polyacrylonitrile particles.

• 한국소음진동공학회논문집
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• 제12권11호
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• pp.882-889
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• 2002

This paper presents vibration control performance of a squeeze mode ER mount for high static load. After experimentally investigating the field-dependent damping force under the squeeze mode motion, a squeeze mode ER mount which can support 200 kg of static load is designed and manufactured. Displacement transmissibility of the proposed ER mount is experimentally evaluated in frequency domain with respect to the intensity of the electric field, and a sky-hook control algorithm is designed to attenuate unwanted vibration. Vibration isolation capabilities of the flow mode ER mount and rubber mount are compared to those of the proposed squeeze mode ER mount.

• 한국융합학회논문지
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• 제13권4호
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• pp.421-432
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• 2022

본 연구의 목적은 국가별 차이가 고령층의 복지기술 사용의도에 미치는 영향을 비교·분석하는데 있다. 이를 위해 기술수용모델과 구조방정식 분석방법을 활용하여, 한국과 미국에 거주하는 65세 이상 고령자 총 334명(한국 154명, 미국 180명)을 대상으로 복지기술에 대한 지각된 편이성, 지각된 유용성, 사용태도, 사용의도의 직접 및 간접효과 차이를 분석하였다. 분석결과 한국고령층은 '지각된 유용성'이 '사용태도'에 미치는 영향(0.74, p<0.001)이, 미국 고령층은 '지각된 편이성'이 '지각된 유용성'에 미치는 영향(0.75, p<0.001)이 가장 높았고, 통계적으로도 두 국가 간 유의한 차이를 보였다. 이는 장기적 지향성(Long-term Orientation)에 대한 두 국가 간 문화적 차이가 고령자 기술사용의도 차이에 영향을 미치고 있음을 설명할 수 있었다. 본 연구결과를 바탕으로 국가 간 고령자의 복지기술 사용의도를 높이기 위한 활용방안의 차이와 정책적 함의들을 제시하였다.

• 한국소음진동공학회논문집
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• 제16권7호
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• pp.754-761
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• 2006

This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed to reduce force transmitted to the vehicle chassis and finally to protect occupants from injury. In the case of head-on collision, the bumper makes main role of isolation material for collision attenuation. In this study, the proposed bumper system consists of MR impact damper and structures. The MR impact damper utilizes MR fluid which has reversible properties with applied magnetic field. The MR fluid operates under flow mode. The bellows is used for generation of fluid flow. A mathematical model of the MR impact damper is derived incorporating with Bingham model of the MR fluid. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.

• 대한기계학회논문집
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• 제18권10호
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• pp.2706-2711
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• 1994

In this work, an experimental type of torque converter has been constructed and its characteristics have been evaluated by adapting an electrorheological fluid(ERF) as an operating medium. The device was designed by using the equations which were proposed by Carlson et al. The correlation between the rheological behaviour of an ERF and mechanical parameters of the clutch has been investigated. The torque generated by an ERF in this device is sum of one due to the yield strength by polarizing dispersed particles in dielectric oil and one due to the viscous drag. The experimental results are presented in terms of torque and current density as a function of rotational speed at various electric field strength applied. Experimental results showed that the measured torque was rapidly increased with the increase of the electric field, generally being proportional to the rotational speed of the motor. The measured current was shown to be increased with the increased electric field. Also, the current was decreased with the increase of increased with the increased electric field. Also, the current was decreased with the increase of the rotational speed of the motor and reached plateau region after f = 5 Hz.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.147-152
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• 2006

This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed for reduce transmitted force to vehicle chassis and finally protect occupants from injury. In the case of frontal collision, the bumper make main role of isolation material for collision attenuation. In this study, proposed bumper system composed of MR impact damper and structures. The MR impact damper is to adopted MR fluid which has reversible properties with applied magnetic field. MR fluid operates under flow mode with Bingham flow and bellows is used for generation of fluid flow. Mathematical model of MR impact damper incorporated with MR fluid is established. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.