• 한국컴퓨터정보학회논문지
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• 제28권9호
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• pp.1-8
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• 2023

본 논문에서는 임베디드 시스템을 이용한 차량용 다기능 레이다(Multi-Function Radar, MFR) 수평구동장치(Auto-Leveling Equipment, ALE) 구동 전략을 제안한다. 차량용 레이다는 일정 속도로 회전하며 지대공 유도미사일, 유인/무인 전투기 감시정찰 임무를 수행한다. 수평구동장치는 수평구동모듈 4세트로 구성하고 레이다 차량의 수평을 유지하여 시스템의 안정성을 확보한다. 차량의 수평은 임베디드 시스템을 이용하여 경사도를 측정하고, 구동모터를 이용하여 차량의 수평각을 유지한다. 본 논문에서는 수평구동모듈 1세트를 모델링하여 수평구동장치를 축소 구현하여 수평구동장치 설계 향상에 기여한다. 제안하는 구동 전략의 타당성은 MATLAB/Simulink 시뮬레이션으로 입증한다.

• 자동차안전학회지
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• 제9권3호
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• pp.13-18
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• 2017

Since 2015, Euro-NCAP and C-NCAP have enhanced regulation on submarine of rear female passenger. This submarine regulation is a big obstacle to achieve the highest level crash performance. So the objective of this study is to develop new technical way to protect rear female passenger against submarine. In this study, we figured out how design factors of seatbelt affect submarine of rear female passenger by sled test. And we verified that rear passenger submarine can be improved by increasing intersection angle of seatbelt anchor and rotation amount of seatbelt buckle. Based on these results, this paper proposes a new invention of seatbelt buckle and anchor that can improve rear passenger submarine. One is seatbelt buckle that can be detached from stopper to prevent rotation and the other is seatbelt anchor that can be changed the structure so as to incline forward during crash. Finally we proved that submarine of rear female passenger can be improved by the effectiveness of new inventions.

• 자동차안전학회지
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• 제6권2호
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• pp.43-48
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• 2014

The flexible pedestrian legform impactor(Flex-PLI) consisting of a flexible femur and tibia will be tested for pedestrian protection by global technical regulation(GTR) within the next couple of years as a replacement for the existing transport research laboratory(TRL) legform impactor. In this study, a computer aided engineering(CAE) model was used to perform the effect analysis of each injury with regard to the changes in tolerance factors with the baseline results without tolerance. The tolerance factors were the height of impactor from ground reference line, initial velocity of impactor and rotation of impactor.

• 자동차안전학회지
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• 제10권4호
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• pp.13-24
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• 2018

According to DEKRA (a Germany Certification and Inspection Agency)'s accident rate analysis by vehicle defect factor, as a result of analysis of the causes of accidents by flaws, it was found that braking devices accounted for 41%. Defects in the braking system are closely related to the accident, so it is very important to find faulty brking systems to ensure safety. The EU and USA uses ISO brake tester and the Korea is brake teater is first introduse in Japan for vehicle inspection and maintanance. KOTSA introduce the ISO brake tester in order to promote the advanced standardization of the inspection equipment and inspection tecnology, and examined the detection characteristics and applied it to the improvement direction of the brake tester to secure the driving safety.

• Interaction and multiscale mechanics
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• 제4권4호
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• pp.291-311
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• 2011

To simulate the self excited torsional vibrations of rotating drill strings (DSs) in vertical bore-holes, the nonlinear wave models of homogeneous and sectional torsional pendulums are formulated. The stated problem is shown to be of singularly perturbed type because the coefficient appearing before the second derivative of the constitutive nonlinear differential equation is small. The diapasons ${\omega}_b\leq{\omega}\leq{\omega}_l$ of angular velocity ${\omega}$ of the DS rotation are found, where the torsional auto-oscillations (of limit cycles) of the DS bit are generated. The variation of the limit cycle states, i.e. birth (${\omega}={\omega}_b$), evolution (${\omega}_b<{\omega}<{\omega}_l$) and loss (${\omega}={\omega}_l$), with the increase in angular velocity ${\omega}$ is analyzed. It is observed that firstly, at birth state of bifurcation of the limit cycle, the auto-oscillation generated proceeds in the regime of fast and slow motions (multiscale motion) with very small amplitude and it has a relaxation mode with nearly discontinuous angular velocities of elastic twisting. The vibration amplitude increases as ${\omega}$ increases, and then it decreases as ${\omega}$ approaches ${\omega}_l$. Sectional drill strings are also considered, and the conditions of the solution at the point of the upper and lower section joints are deduced. Besides, the peculiarities of the auto-oscillations of the sectional DSs are discussed.

• 한국정밀공학회지
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• 제4권4호
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• pp.36-42
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• 1987

Very accurate calibration is needed to index tables which are necessary for precision angle measurement. The repeatability of index table is less than 0.2 second, so that attentions should be paid to choosing devices to be used in the calibration of index tables. The auto- collimators have been used in the calibration of index tables, but the repeatability of auto- collimators is bad compared with that of index table. In place of autocollimators, we described a method which uses electric comparators which are possessed by most precision measurement laboratories. Electric comparators are set to measure small angle displacement without interrupting the rotation of index tables and the signals of two electric comparators are added to remove the run-out errors of the shafts of index tables. Two index tables have been calibrated simulataneously by this method and the measurement data have been analyzed by the least squares method. We compare the calibration results with those of methods using autocollimator and auto- matic autocollimator and are able to know that the data of electric comparator method lie between the data of autocollimator methods. The repeatability of measurement is less than 0.02 second. The electric comparator method is economical and capable of reducing the uncertainty of the measurement.

• Wind and Structures
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• 제15권6호
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• pp.509-529
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• 2012

Traditionally, a quasi steady response concerning the aerodynamic force and moment coefficients acting on a flat plate while 'flying' through the air has been assumed. Such an assumption has enabled the flight paths of windborne debris to be predicted and an indication of its potential damage to be inferred. In order to investigate this assumption in detail, a series of physical and numerical simulations relating to flat plates subject to autorotation has been undertaken. The physical experiments have been carried out using a novel pressure acquisition technique which provides a description of the pressure distribution on a square plate which was allowed to auto-rotate at different speeds by modifying the velocity of the incoming flow. The current work has for the first time, enabled characteristic pressure signals on the surface of an auto-rotating flat plate to be attributed to vortex shedding.

• 대한물리의학회지
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• 제11권4호
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• pp.27-32
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• 2016

PURPOSE: This study compared the immediate effect of a passive mobilization of upper cervical spine (Kaltenborn's joint mobilization) and an active upper cervical stretching (Olaf's Auto-stretching) on patients with neck pain and ROM. METHODS: Twenty-three subjects were randomized selected in the passive group (Kaltenborn's joint mobilization) included twelve subjects and the active group (Olaf's Auto-stretching) included eleven subjects. VAS (Visual Analogue Scale) was measured before and after neck rotation performance. DUALER IQ PRO (JTECH Medical, U.S.A.) was used to measure the neck ROM. Mean value of double measurement was used before performance and after performance. SPSS version 18 was used to compare values independent t-test and paired t-test were used to compare pain and ROM. RESULTS: There are significant difference in the pain and the ROM in both of two group (p<.05). But there are no significant difference pain and ROM between two groups. CONCLUSION: Both of the passive mobilization of upper cervical spine and the active upper cervical stretching are effected on symptom improvement of patients with neck pain reduction and ROM increasing. Especially active upper cervical stretching is more economical, because it has similar effects with the passive mobilization, help to maintain the treatment effect of therapist by themselves and can help to save medical expenses of patients.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.453-460
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• 2011

This study was carried out to test a red pepper tedding factors which is needed for design and development of an auto-tedding machine and a performance. According to this test, the results can be summarized as follows: The results of the tedding factors test according to shape of rotary blade, which is the 0.4 to 0.5 mm brush type, was found to be the most appropriate. As a result of tedding ratio which includes brush diameters, driving velocities and rotation velocities, there was generally no significance difference, but the red pepper tedding efficiency was found to be 39.7%. The moisture drying rate of red pepper was found to be 0.9 %w.b./h in prototype auto-tedding machine and 0.4 %w.b./h in traditional practice. The drying time was found to be 3 days in prototype auto-tedding machine and the traditional practice was 6 days. The average variable coefficient of the red pepper moisture content was found to be 16.8% in prototype auto-tedding machine in comparing with the traditional practice of 35.0%. This test showed a difference around two times, and this difference was evaluated to be the reason for irregular drying and different drying times.

• 전자공학회논문지S
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• 제34S권2호
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• pp.94-103
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• 1997

The WCHF-FSJTC (wavelet circular harmonic function frequency selective joint transform correlator) using th wavelet transformed CHF as the reference image in FSJTC is proposed for rotation invariant pattern recognition. Since the wavelet transform has the property of feature extraction, the proposed system can have the better DC (discrimination cpability) and the higher SNR(signal to noise ratio) compared with the conventional CHF-CJTC(circular harmonic function conventional joint transform correlator). And since the structure of the proposed system is FSJTC which can eliminate auto-correlation and cross-correlation between input images, it can eliminate false alarm caused by the overlapping among correlation peaks. The used wavelet functio is the morlet function, which is proper for the reference image used in this paper. the optimal dialation parameter and oscillation frequency of the wavelet function are also achieved with varying the parameters of the wavelet function. The computer simulation shows that the proposed system has the best performance when the dilation parameter is 0.8 and the oscillation frequency is 0.48.