• 한국소음진동공학회논문집
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• 제21권10호
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• pp.897-904
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• 2011

When whole-body is exposed to vertical vibration, asymmetry shape of human body affects the response on the translational(fore-aft, lateral, vertical) and rotational(roll, pitch, yaw) motion. While the translational motion has been studied with various titles, it has been rare to study the rotational motion of human body exposed to vertical excitation because of lack of experimental equipment. This study was performed by using a 6-axis force plate installing strain gage type sensors for the rotational response. Sixteen male subjects were exposed to vertical vibration on rigid seat in order to investigate apparent mass of three translational motion and apparent eccentric mass of three rotational motion. Random signal was generated to make excitation vibration which was on an effective frequency range of 3~40 Hz, and magnitude of 0.224 m/$s^2$ r.m.s. The frequency range and magnitude used was selected for the vibration of passenger vehicle on idling condition. As the result, cross-axis apparent masses of fore-and-aft and lateral direction were not significant showing 20 % and 3 % of vertical apparent mass relatively. And apparent eccentric mass of pitch motion was dominant when compared to that of roll and yaw motion, which is reasoned by asymmetry direction of human body sitting on a seat.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.218-223
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• 2011

Seated human subjects have been exposed to vertical vibration so as to investigate six-axis biodynamic response. Sixteen males were exposed to random vertical vibration in the frequency range(3~40Hz) at one vibration magnitude(0.224m/$s^2$ r.m.s.). Forces were measured in the vertical, fore-and-aft, lateral, roll, pitch and yaw direction on the seat. The median of cross-axis apparent mass magnitude in the fore-and-aft direction could reach up to 20% of the apparent mass magnitude at resonance frequency. And the median of apparent eccentric mass magnitude in the roll direction could reach up to 15% of the apparent eccentric mass magnitude in the pitch direction at resonance frequency. But cross-axis apparent mass in the lateral direction and apparent eccentric mass in the yaw direction showed very small.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.241-245
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• 2003

When considering the effects of whole-body vertical vibration, it is valuable to have an understanding of the mechanical characteristics (mechanical impedance and apparent mass) of the body. This paper addresses experimental results carried out to investigate the characteristics of apparent masses fer 41 Korean. The apparent masses of the seated human body in vertical direction were measured during different experimental conditions, such as vibration excitation level (0.5-2 ms$\^$-2/ r.m.s). frequency range (1-50Hz), and upper body posture (relaxed, normal and backrest-upright). We showed the average of all subjects and all conditions and compared the results with ISO5982/DIS (2000).

• 한국소음진동공학회논문집
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• 제20권12호
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• pp.1121-1127
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• 2010

Human characteristic responding to idle vibration on passenger vehicle was studied to find if affected by seating posture of passenger. When twelve male subjects are exposed to moderate vertical vibration of 0.224 $m/s^2$ r.m.s. at frequency range from 3 Hz to 40 Hz, it was found that seating posture significantly affects to biodynamical characteristics, apparent mass and apparent eccentric mass, at most range of idle vibration frequency(20~40 Hz). The supported thigh contact on rigid seat showed bigger values in the two biodynamical characteristics than the average thigh contact. The bigger apparent mass and apparent eccentric mass in the seating posture of the supported thigh contact can be assumed more strengthened muscle at the frequency range.

• 한국소음진동공학회논문집
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• 제13권8호
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• pp.645-650
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• 2003

This paper introduces attempts to obtain the 'representative'characteristics of the apparent mass (or dynamic mass) of seated Korean subjects under vertical vibration. Individual responses of driving-oint apparent masses obtained from forty one Korean subjects are illustrated. Four kinds of vibration levels and three different sitting postures are selected to collect the characteristic responses of each subject. Those individual responses are used to estimate the 'mean'apparent mass, which may be expected to be a representative model to Korean subjects. Several interesting features of the estimated apparent mass are suggested and compared to those of ISO 5982.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.369-374
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• 2004

This study aims to measure an apparent mass of a seated human body at the sitting posture in a passenger car in the frequency range from 1 to 20 Hz and to investigate the dynamic characteristics. Thirty subjects joined the test where eight levels of acceleration from $0.1m/s^2\;to\;2.0m/s^2$ were used to excite seated human body. Most of apparent mass curves showed two peaks in the frequency range of $4\sim9Hz$, first peak was clearer at the contact point of the seat and the hip, and the second one at the contact point of the backrest and the back. Both peak frequencies were found to move down to lower frequencies with increase of acceleration magnitude. Shapes of apparent mass curves were clearly different from those at erect posture especially in the frequency range around and above the second peak.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.522-528
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• 2000

Dynamic characteristics of seated human body were investigated by measuring apparent masses of eight different seating subjects exposed to vertical vibration. Two types of vibration signals - one is random signals over 1 to 30Hz having flat spectral density and the other is signals measured on seat rail in passenger car under driving conditions - were employed. It was found that the apparent masses are highly dependent on vibration level rather than type of the vibration signals. Based on the apparent mass measurements, a mathematical model of the human body in seating posture was developed by using genetic algorithm. Three-degree-of-freedom model was satisfactory in describing apparent mass of seated human body.

• 대한기계학회논문집A
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• 제31권2호
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• pp.145-151
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• 2007

Impulsive excitation on vehicle produces shock-type vibration on the seat, which has major frequencies and damping ratios dependent on the characteristics of the suspension, the tire, the seat cushion and so on. The response of single degree of freedom model to a half-sine force input was considered as simple shock-type vibration signal. Quasi-apparent-mass for fifteen subjects was measured with the shock-type vibration generated on a rigid seat mounted on the simulator, so its nonlinearity was apparently found over 6.3 Hz according to the difference of magnitude of the shock.

• 유기물자원화
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• 제9권4호
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• pp.105-110
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• 2001

쓰레기의 효과적인 처리방안을 제시하고 장래 대책을 수립하는데 자료로 활용하도록 하기 위해서 순천시 생활쓰레기의 물리 화학적 특성을 조사하였다. 발생 쓰레기의 계절별, 성상별 특성을 조사 분석하여 다음의 결과를 얻었다. 생활쓰레기의 겉보기밀도는 가연성쓰레기가 $219kg/m^3$, 비가연성쓰레기는 $391kg/m^3$로 나타났다. 가연성쓰레기 중에서 음식물쓰레기의 습윤질량 중량비 가중평균은 38.1%를 차지하였으며, 음식물쓰레기를 제외한 가연성쓰레기는 49.6%를 나타내었다. 음식물쓰레기를 제외한 가연성쓰레기의 수분함량, 가연분함량 및 회분함량의 가중평균은 각각 16.9%, 68.1% 및 15.0%로 나타나 소각처리의 특성이 양호하게 나타났다. 음식물쓰레기를 제외한 가연성쓰레기의 저위발열량은 2,962kcal/kg로 나타나 소각처리의 특성이 아주 양호하게 나타났다.

• 공업화학
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• 제10권4호
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• pp.548-556
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• 1999

질소 분위기에서 폴리에틸렌 열분해의 속도론적 연구를 $10^{\circ}C/min$와 $50^{\circ}C/min$ 사이의 여러 가지 가열속도에서 비등온 질량감소 기술을 이용하여 수행하였다. 속도 상수들에 대한 정보를 얻기 위하여 질량감소 곡선 및 그 미분값을 Kissinger, Freeman-Carroll, Flynn-Wall, Coats-Redfern, Chatterjee-Conrad, Friedman, Horowitz-Metzger 및 Ozawa 방법과 Denq 방법을 이용하여 해석하였다. 연구에 사용된 수학적인 방법에 따라 속도 상수의 결과값에 많은 차이가 있음을 알 수 있었으며, 따라서 열분해의 속도 상수 결정에 있어서는 각 방법의 장 단점에 대한 비교 분석 연구가 선행되어야 할 것으로 판단되었다. 본 연구로부터 HDPE의 겉보기 활성화 에너지의 값이 LDPE의 값보다 크게 나타냄을 확인할 수 있었다.