• 한국산업융합학회 논문집
• /
• 제24권6_2호
• /
• pp.841-848
• /
• 2021

This study investigated the acceleration characteristics of rock slopes when earthquakes, which have not been studied much in Korea, occur. The rock slope was modeled with a similar raw of 1/20 in consideration of the height(10m), roughness, strength, and the joint dips(20°). After the completion of the model, a shaking table tests was conducted according to the magnitude of the acceleration and the type of seismic wave. The maximum acceleration was greater in the short-period seismic wave than in the long-period seismic wave, and the maximum acceleration was larger in the small acceleration. The rock slope was close to a rigid block and a structure more vulnerable to the long period wave than to the short period wave. In the event of an earthquake smaller than the domestic earthquake-resistant maximum design acceleration(0.154g), safety management of the rock slope was required.

• Journal of Biosystems Engineering
• /
• 제26권4호
• /
• pp.315-322
• /
• 2001

Agricultural products can be damaged due to the vibration of transporting trailer on the off-road. So, this study was conducted to identify the vibration characteristics of the agricultural products transporting trailer by measuring the vertical acceleration according to positions on the trailer loaded with agricultural products. The results of this study can be summarized as follows: 1. At non-operating state of engine, the larger vertical acceleration was occurred at rear side compared with front side in the case of 4.5Hz of vibration frequency. But, in the case of 53.5Hz of frequency, the maximum vertical acceleration at front side of trailer was higher than value at rear side. So, the maximum acceleration at front side of the trailer was increased with the increase in frequency. 2. At operating state of engine, the maximum vertical acceleration at front side of the trailer was increased with the increase in frequency. 2 At operating state of engine, the maximum vertical acceleration delivered through the hitch from the engine was occurred at front side of the trailer as $3.0\times10^{-3}m/s^2$, in the case of 8.75Hz of frequency. But, in the case of 102.5Hz of high frequency, the maximum vertical acceleration was occurred at rear side of the trailer. 3. When the power tiller loaded with pear of 325kg was travelling on the artificial uneven road of 3cm height, the maximum acceleration was occurred at rear side of the trailer as $4.7\times10^{-3}m/s^2$at 3.75Hz of frequency. But, that was occurred at diagonal of the trailer 43.5Hz and 91.25Hz, which meant that there was rolling and pitching on the trailer. 4. At operating state of engine, the mean acceleration of the trailer delivered through the hitch according to the increase in frequencies was showed the maximum value at range of 40-90Hz. At rear side of traiㅣer, the maximum value was occurred at about 40Hz, and that was reduced according to the increase in frequencies and diminished at about 100Hz. 5. When the power tiller loaded with pear of 32.5kg was travelling on the artificial uneven road of 3cm height, the mean acceleration by the increase in frequencies was showed lower level at rear side than front side of the trailer. This was opposite configuration to the Hinsch’s results tested with air-conditioned truck. This means that the shorter length of the trailer, the more effect of engine vibration is transferred to the front side of trailer.

• Journal of Electrical Engineering and Technology
• /
• 제7권2호
• /
• pp.255-263
• /
• 2012

This paper presents the smart interacting multiple model (SIMM) using the concept of predicted point and maximum noise level. Maximum noise level means the largest value of the mere noises. We utilize the positional difference between measured point and predicted point as acceleration. Comparing this acceleration with the maximum noise level, we extract the acceleration to recognize the characteristics of the target. To estimate the acceleration, we propose an optional algorithm utilizing the proposed method and the Kalman filter (KF) selectively. Also, for increasing the effect of estimation, the weight given at each sub-filter of the interacting multiple model (IMM) structure is varying according to the rate of noise scale. All the procedures of the proposed algorithm can be implemented by an on-line system. Finally, an example is provided to show the effectiveness of the proposed algorithm.

• Earthquakes and Structures
• /
• 제2권2호
• /
• pp.171-187
• /
• 2011

Rational scaling of design earthquake ground motions for tall buildings is essential for safer, risk-based design of tall buildings. This paper provides the structural designers with an insight for more rational scaling based on drift and input energy demands. Since a resonant sinusoidal motion can be an approximate critical excitation to elastic and inelastic structures under the constraint of acceleration or velocity power, a resonant sinusoidal motion with variable period and duration is used as an input wave of the near-field and far-field ground motions. This enables one to understand clearly the relation of the intensity normalization index of ground motion (maximum acceleration, maximum velocity, acceleration power, velocity power) with the response performance (peak interstory drift, total input energy). It is proved that, when the maximum ground velocity is adopted as the normalization index, the maximum interstory drift exhibits a stable property irrespective of the number of stories. It is further shown that, when the velocity power is adopted as the normalization index, the total input energy exhibits a stable property irrespective of the number of stories. It is finally concluded that the former property on peak drift can hold for the practical design response spectrum-compatible ground motions.

• 한국지반공학회지:지반
• /
• 제1권1호
• /
• pp.13-20
• /
• 1985

SHAKE 프로그램을 이용하여 연약지반으로 분포되어 있는 방콕지역에 대한 지진표답을 지표면의 가속도응답 스펙트럼과 최대 가속도로서 분석하였다. 기초암반의 최대 가속도와 부월주기가 증가됨에 따라 지표면의 최대 가속도는 증가되고 그 값은 0.3g 로 수관되었다. 아울러 지진응답 스펙트럼의 성질에 대해서도 설명되었다.

• The Journal of Korean Physical Therapy
• /
• 제22권6호
• /
• pp.59-63
• /
• 2010

Purpose: Driving a car is an essential component of daily life. For safe driving, each driver must perceive sensory information and respond rapidly and accurately. Brake response time (BRT) is a particularly important factor in the total stopping distance of a vehicle, and therefore is an important factor in traffic accident prevention research. The purpose of the current study was (1) to compare accelerometer. BRTs analyzed by three different methods and (2) to investigate possible correlations between accelerometer-BRTs and foot switch-BRTs, which are measured method using a foot switch. Methods: Eighteen healthy subjects participated in this study. BRT was measured with either a tri-axial accelerometer or a footswitch. BRT with a tri-axial accelerometer was analyzed using three methods: maximum acceleration time, geometrical center, and center of maximum and minimum acceleration values. Results: Both foot switch-BRTs and accelerometer-BRTs were delayed. ANOVA for accelerometer BRTs yielded significant main effects for axis and analysis, while the interaction effect between axis and analysis was not significant. Calculating the Pearson correlation between accelerometer-BRT and foot switch-BRT, we found that maximum acceleration time and center of maximum and minimum acceleration values were significantly correlated with foot switch-BRT (p<0.05). The X axis of the geometrical center was significantly correlated with foot switch-BRTs (p<0.05), but Y and Z axes were not (p>0.05). Conclusion: These findings suggest that the maximum acceleration time and the center of maximum and minimum acceleration value are significantly correlated with foot switch-BRTs.

• 한국도로학회논문집
• /
• 제15권4호
• /
• pp.147-154
• /
• 2013

PURPOSES: To analyze the specific factors of drivers behaviors that amount of cause the greenhouse gas emissions per vehicle. METHODS: Drivers behaviors at intersections are analyzed on the conditions of acceleration and deceleration. RESULTS : First, it is resulted greenhouse gas emissions per vehicle is produced more at intersections than at the main lines of highway. Second, it is resulted that the average speed, the average acceleration rate and the maximum speed are three major factors to produce greenhouse gas per vehicle in acceleration sections. Third, it is resulted that rapid deceleration 20m before entering intersections is the major factor to produce greenhouse gas per vehicle in deceleration sections. CONCLUSIONS: At intersections, sudden acceleration and deceleration is not good for greenhouse gas emissions. Thus, and the average speed, the average acceleration rate and the maximum speed are the chosen as factors to be controlled for drivers' behavior to reduce vehicles' greenhouse gas at intersections.

• 제어로봇시스템학회논문지
• /
• 제14권11호
• /
• pp.1146-1154
• /
• 2008

This paper presents a method for the acceleration analysis of multi-legged walking robots in consideration of the frictional ground contact. This method is based on both unified dynamic equation for finding the acceleration of a robot's body and constraint equation for satisfying no-slip condition. After the dynamic equation representing relationship between actuator torques and body acceleration, is derived from the force and acceleration relationship between foot and body's gravity center, the constraint equation is formulated to reconfigure the maximum torque boundaries satisfying no-slip condition from given original actuator torque boundaries. From application of the reconfigured torques to the dynamic equation, interested acceleration boundaries are obtained. The approach based on above two equations, is adapted to the changes of degree-of-freedoms of legs as well as friction of ground. And the method provides the maximum translational and rotational acceleration boundaries of body's center that are achievable in every direction without occurring slipping at the contact points or saturating all actuators. Given the torque limits in infinite normsense, the resultant accelerations are derived as a polytope. From the proposed method, we obtained achievable acceleration boundaries of 4-legged and 6-legged walking robot system successfully.

• 대한의용생체공학회:의공학회지
• /
• 제19권6호
• /
• pp.603-609
• /
• 1998

가속도 변화에 따른 뇌의 미만성 부상을 해석하기 위하여 성인 및 2세, 6세아의 머리 부분에 대한 유한 요소 모델을 개발하였다. 외력은 최대값이 200g인 삼각형 형태의 가속도를 가하였으며, 가속도의 방향, 지속시간에 따른 변화를 해석하였다. 가속도 변화에 따라 발생되는 뇌내의 전단력 분포는 뇌간, 뇌교 및 중뇌등 신경조직이 밀집된 곳에서 크게 발생되어 이곳에서 미만형 부상이 발생할 확률이 높음을 알 수 있었으며, 특히 6세아 모델의 경우 뇌간에서의 최대 전단력이 굴전 형태의 회전가속도 받았을 때 가장 크게 나타나는 결과를 보여 개발된 모델이 임상결과와 일치함을 보여주고 있었다. 가속도 지속 시간이 길어짐에 따라 뇌내에 발생되는 압력 및 최대 전단력의 크기가 증대되고 있었으며, 유아모델의 경우 성인모델에 비하여 가속도 방향과 관계없이 낮은 압력이 발생하였지만 발생압력이 감소하지 않고 지속되는 현상을 보이고 있었다. 그리고 각 가속도에 의한 미만성 부상을 예방하기 위한 안전지수로는 현재 탑승자의 안전 설계에 활용되고 있는 HIC보다는 최대 전단응력이 더 적절한 부상 예측인자임을 알 수 있었다.

• 대한기계학회논문집
• /
• 제6권4호
• /
• pp.323-330
• /
• 1982

The vibration characteristics of continuous span periodically supported beams with moving loads are determined theoretically and experimentally. Moving loads are assumed to travel at constant acceleration with constant magnitude. Analyses by using the Fourier Transform technique are developed to determine the dynamic performance of moving load interacting with multiple and continuous beam. Equation of motion for the moving load is non-dimensionalized. Non-dimensional deflection proflies of continuous beam are presented in detail for the single concentrated moving load with constant acceleration. Experimental moving load and continuous beam models are developed. The maximum deflections at each midpoints 5,7 and 9 span beam are measured and their non-dimensional maximum deflections are presented. The non-dimensional maximum deflection of continuous beam is compared with measured maximum deflection of 9 span beam and found to agree reasonably well. The deflection of continuous beam due to moving load with acceleration is strongly influenced in the resonance region.