• 한국방사선학회논문지
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• 제12권5호
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• pp.651-658
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• 2018

방사선사는 일반촬영 시에 다양한 환자를 만나게 된다. 노령환자, 유아 등 몸이 불편한 환자를 검사하게 된다. 소규모의 병 의원에는 방사선사가 혼자 업무를 보는 경우가 자주 발생한다. 이러한 경우 방사선사의 두 손은 환자의 자세를 유지하는데 사용되어지기 때문에 촬영에 있어서 어려움을 느끼게 된다. 본 연구는 이러한 문제점을 극복하고자 진단용 방사선 발생 발판 스위치를 고안하여 실험하였다. 제작한 발판 스위치를 진단용 엑스선 촬영장치에 장착하여 조사선량 재현성 시험, kVp, mAs, 백분율평균오차와 같은 정량적 평가를 실시하였다. 결과적으로 발판 스위치 사용에 대한 정량적 평가는 조사선량 재현성 시험에서 변동계수가 0.05이하로 측정되었고 kVp 시험에서는 백분율 평균오차가 ${\pm}10%$ 이내로 측정되었다. mAs 시험에서도 백분율 평균오차가 ${\pm}20%$ 이내로 측정되었다. 이는 진단용 방사선 발생장치의 검사기준 범위에 모두 부합하여 사용상 문제점은 제시되지 않았다. 또한 현재 근무 중인 방사선사를 상대로 유용성에 관한 정성적 평가를 실시하였다. 결론적으로 발판스위치의 엑스선 발생효율의 정량적 평가에서는 실험된 검사가 엑스선 발생장치 장비 기준 범위에 부합하였으며 설문을 통한 평가에서도 먼저 병 의원에서 근무하는 방사선사를 상대로 발판 스위치를 사용한 이후 설문을 통해 발판 스위치에 대한 편리성과 활용성에 대해 설문 실시한 결과는 발판스위치 사용은 임상에서 많은 도움을 줄 수 있는 긍정적인 결과로 나타내었다. 그러므로 진단용 엑스선 촬영용 발판 스위치를 사용하면 방사선 기술자 작업의 신속성과 정확성을 효과적으로 향상시킬 수 있으므로 의료 서비스 만족도를 높이는 데 효과적으로 사용할 수 있을 것이다.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1292-1298
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• 2017

In this paper, we represent a nonlinear identification of electronic brake pedal behavior in the brake-by-wire (BBW) system based on hybrid group method of data handling (GMDH) and genetic algorithm (GA). A GMDH is a kind of multi-layer network with a structure that is determined through training and which can express nonlinear dynamics as a mathematical model. The GA is used in the GMDH, enabling each neuron to search for its optimal set of connections with the preceding layer. The results obtained with this hybrid approach were compared with different nonlinear system identification methods. The experimental results showed that the hybrid approach performs better than the other methods in terms of root mean square error (RMSE) and correlation coefficients. The hybrid GMDH/GA approach was effective for modeling and predicting the brake pedal system under random braking conditions.

• 한국소음진동공학회논문집
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• 제23권2호
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• pp.160-166
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• 2013

This paper proposes a driver supportive device with haptic cue function which can be applicable for vehicles adopting manual transmission system to transmit gear-shifting information to a driver by kinesthetic forces. This haptic cue function is implemented on accelerator pedal by utilizing magnetorheological(MR) fluid and clutch mechanism. In order to achieve this goal, an MR clutch mechanism is devised to be capable of rotary motion of accelerator pedal. The proposed MR clutch is then optimally designed and manufactured under consideration of spatial limitation of vehicles. After transmission torque is experimentally evaluated according to field intensity. The manufactured MR clutch is integrated with accelerator pedal and electric motor to establish the haptic cue device. Control performances are experimentally evaluated via a simple feed-forward control algorithm.

• 한국운동역학회지
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• 제22권1호
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• pp.65-73
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• 2012

The purpose of this study was to identify the saddle to pedal length contributing to successful performance in kayak using a kayak ergometer. Ten male elite kayak players participated in this study. players were tested on the kayak ergometer which was varied saddle to pedal length by the knee flexion angle(90deg; 120deg; 150deg) to measure stroke frequency, paddling amplitude, joint angle, RoM and angular velocity, foot pressure and force, iEMG using the 3D motion system, foot pressure system and EMG wireless system. At a results, rowing at 120deg on knee flexion angle showed higher stroke frequency and paddling amplitude than other knee flexion angles. RoM at upper extremity showed not significant difference between knee flexion angles. But there were significant differences in thorax and pelvis rotation RoM, knee flexion-extension RoM in each condition. In addition, foot pressure, force and iEMG were significantly different in knee flexion angles. Study showed that changed of saddle to pedal length affected rowing performance kinds of stroke frequency, paddling amplitude. The most important thing, increased range of motion in pelvic and thorax has occurred by force that generated foot-bar to seat. Not only that, but it seems to be attributed to a technical adaptation developed to maximum rowing performance.

• 한국정밀공학회지
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• 제28권12호
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• pp.1434-1440
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• 2011

In this paper, we assessed muscular activities of lower limbs and foot pressure for car and bus drivers according to operating three electronic pedals that we developed. To analyze drivers' physical exhaustion, muscular fatigue of lower limbs was evaluated. Eleven car drivers and six urban bus drivers were participated in this experiment. The virtual driving system was used for the real driving environment. The virtual driving system was comprised of a spring seat, a steering wheel, pedals (clutch, excel and brake pedals), a manual transmission and a virtual driving simulation. For the real vibration like situation on the road, six degree of freedom motion base system was used. Measured muscles were rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius (Gn) muscles. For the quantitative muscular activities, integrated electromyography (IEMG) was analyzed. Muscular fatigues also were analyzed through the analysis of the median frequency. In addition, foot pressures were analyzed and compared through the peak and averaged pressure during the operating three developed electronic pedals. The experiments are conducted with total 17 drivers, 11 general public and 6 drivers. As a result of the analysis, electromyogram and fatigue analysis through intermediate frequency reduction for pedal-1 more efficient than other pedals. And foot pressure also was decreased. Consequently, we suggested the most efficient pedal and method to minimize the amount of cumulative fatigue.

• 자동차안전학회지
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• 제12권2호
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• pp.7-13
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• 2020

Recently, there is a big issue of downsizing on brake system according to fuel efficiency and regenerative braking cooperation control. Especially, small cars have improved in a variety ways such as electric vehicle and smart car compared to previous small cars. So, small brake system is strongly required in the car industry. A new small brake system for light compact vehicles was proposed in this paper. For this system, the solid type disc and caliper were newly developed. And the important design factors were considered to reduce brake size. First, we calculated the temperature rise of disc through heat capacity formula and CAE analysis. Second, we analyzed the housing and carrier stiffness of caliper to select the reasonable condition. Finally, the superiorities of the developed brake system were verified by heat capacity, consumption liquid level, braking feeling, judder, wear test and regenerative braking cooperation control analysis. A developed brake system is expected to be useful for brake system of light compact platform.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.8-13
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• 2012

In this paper, Hybrid Electric Vehicle is directly designed and manufactured for base study of HEV's system and Green Car. Foundation design consists of power train design and the frame design. The power train concept includes motor, engine, generator and battery. And the concept of the frame is the single-seat of this self-made HEV. A frame installed in hybrid system contains suspension, steering wheel, seat, accelerating pedal, brake pedal, clutch handle and various chassis parts with bearings. Electromagnetic clutch is equipped to transmit engine power to drive axle. The control algorism make using LabVIEW to control of an engine and a motor depending on drive condition. A parallel type hybrid system is manufactured to control operation of a motor and an engine depending on vehicle speed.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.477-481
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• 2007

In this article we present a new, reference model based, unified strategy for engine control. Three main modes are considered: first is the driver control mode where the driver controls the engine via the pedal position; second is the dashpot mode, that is, when the driver takes his foot off the pedal; and, lastly is the idle speed control mode. These modes are unified so that seamless transitions between modes now becomes possible. The unification is achieved due to the introduction of a reference model for the engine speed whereby only the desired engine speed is different for different modes while the structure of the control system remains the same for all the modes. The scheme includes an observer that estimates unknown engine load torque. A proof of robustness with respect to unknown load disturbances both within the operating modes and during intermode transitions is given.

• International Journal of Automotive Technology
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• 제4권1호
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• pp.41-45
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• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.147-152
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• 2009

This study was conducted to observe the change of limbs stroke and respiration gas parameters in our new bicycle fitness system. We hypothesized that the variable force of left and right limbs might be effective for sensing stimulation in modified new unequal pedal bicycle system. It has been developed, which can provide visual information and different length of pedal with left and right limbs. Experimental results showed different activities between the left and right limbs where the activity of the left limb increased than that of right limb. Especially, the soleous muscle activity increased both in control and experimental groups by this training method. But oxygen and carbon dioxide partial pressures in respiratory gas increased during training method. These results suggest that acidosis of blood was led by this process. Consequently, this bicycle training is concluded that aerobic training could affect different limb activities. Finally, we expect that our new bicycle system will be effective for healthcare with proper balance between the left and right limbs.