• 대한기계학회논문집
• /
• 제12권3호
• /
• pp.481-488
• /
• 1988

본 연구에서는 판이론으로서는 해석할수 없는 집중충격하중의 작용점을 포함 한 유한판(정방형판)의 충격응력을 이론적으로 해석하는 방법을 제안하고저 하며 포성 재료로서 손쉽게 구할수 있고 파괴에 큰 에너지가 소요되지 않은 유리판을 대상으로 하여 3차원 동탄성이론을 이용하여 강구의 고속충돌에 의해서 유리판에 발생하는 충격 응력을 해석하였다. 또한 3차원 동탄성이론에서는 Laplace역변환이 곤난하므로, 고 속 Fourier변환의 알고리즘을 이용하였으며, 충격하중의 크기는 실측이 곤난하여 Lag- range의 고유판이론과 Hertz의 접촉이론으로부터 결정하였으며 단순지지된 정방형유리 판에 고속충격을 가하여 계측된 변형율변동과 본이론해석 결과와를 비교하여 응력해석 방법의 적용성을 명확히 하였다.

• 대한기계학회논문집
• /
• 제14권2호
• /
• pp.298-309
• /
• 1990

In this paper, a new method is suggested to analyze impulsive stresses at loading poing of concentrated impact load under certain impact conditions determined by impact velocity, stiffness of plate and mass of impact body, etc. The impulsive stresses are analyzed by using the three dimensional dynamic theory of elasticity so as to analytically clarify the generation phenomenon of cone crack at the impact fracture of fragile materials (to be discussed if the second paper). The Lagrange's plate theory and Hertz's law of contact theory are used for the analysis of impact load, and the approximate equation of impact load is suggested to analyze the impulsive stresses at the impact point to decide the ranage of impact load factor. When impact load factors are over and under 0.263, approximate equations are suggested to be F(t)=Aexp(-Bt)sinCt and F(t)=Aexp(-bt) {1-exp(Ct)} respectively. Also, the inverse Laplace transformation is done by using the F.F.T.(fast fourier transform) algorithm. And in order to clarity the validity of stress analysis method, experiments on strain fluctuation at impact point are performed on a supported square glass plate. Finally, these analytical results are shown to be in close agreement with experimental results.

• 대한기계학회논문집B
• /
• 제21권11호
• /
• pp.1413-1421
• /
• 1997

A new control method to alleviate the impulsive noise at the exit of high-speed railway tunnel was applied to the compression wave at the entrance of the tunnel. This method uses the interaction phenomenon of unsteady expansion wave and unsteady compression wave. Unsteady expansion wave was assumed to be made instantaneously by the simple theory of shock tube. Total Variation Diminishing method was employed to solve the axisymmetric unsteady compressible flow field with a specified compression wave. Numerical results show that the maximum pressure gradient of the propagating compression wave decreases with increase of the wave length of the unsteady expansion wave. It is found that the impulsive noise reduction can be obtained when the unsteady expansion wave with a large wave length is emitted just before the train enters the tunnel. The present results give the possibility to reduce the impulsive noise at the exit of tunnel.

• 한국소음진동공학회논문집
• /
• 제18권7호
• /
• pp.746-755
• /
• 2008

This research presents a laboratory study on subjective response of impulsive sound caused by construction site (breaker and blasting). The sources are sampled from outdoor noise and their levels range from 40 to 75 dBA at the interval of 5 dBA. The noise unit is based on A-weighted sound exposure level(ASEL; $L_{AE}$). To make equal ASEL of listening level, finite impulse response(FIR) filter is applied to the originally sampled source to include the effect of propagation attenuation. Sixty-three subjects, forty-two males and twenty-one female, between 18 and 29 years of age, participated in the experiment. The evaluation method of jury test adopted a semantic difference method(SDM). In the test results for impulsive noise, the subjective response of blasting noise was higher than that of breaker noise. The result of %HA that has been combined responses of the three methods except for pink-noise was executed by regression analysis and was shown as the following equation.: $%HA=746.53/(1+{\exp} (L_{AE}-93.3))+0.34$.

• 한국생활과학회지
• /
• 제14권6호
• /
• pp.985-994
• /
• 2005

The objective of this study was to investigate differences in clothing behavior and individual characteristics of female college students by their body cathexis and clothing attitude. The college students selected by random sampling were classified into four groups by their body cathexis and clothing attitude: positive congruity(positive body cathexis and clothing attitude, G1), positive incongruity(negative body cathexis and positive clothing attitude, G2), negative congruity(negative body cathexis and clothing attitude, G3), negative incongruity(positive body cathexis and negative clothing attitude, G4). The results were as follows: G1 was high in both public and personal self-esteem and self-image, extroverted, refined and impulsive. G2 were fashion opinion leaders, highly uneasy about society, highly impulsive, modem, peculiar, creative and introspective. G3 was highly uneasy about society, low in self-esteem, and less impulsive. G4 was low in both public self-esteem and fashion innovation, and avoided impulsive buying.

• 한국정밀공학회지
• /
• 제18권10호
• /
• pp.194-199
• /
• 2001

In this paper, we propose a new locomotive mechanism using impulsive force for microcapsule-type endoscope. It has the compact size for movement in the colon and actuating mechanisms for hi-directional movement. The actuating mechanism resembles a pneumatic cylinder and consists of body, inertia mass(piston). spring. pneumatic source and calve. When valve is ON, the pneumatic impulsive force between piston and body drives them in two opposite direction. As the air in the body is passed away, the contrary movements are occurred by spring reaction. Therefore, the direction of body's motion is determined by the relative magnitude of two opposite impulsive forces, i.e., pneumatic and spring force. The effect of two impulsive forces can simply be controlled by On-Off time of solenoid valve.

• 인터넷정보학회논문지
• /
• 제17권3호
• /
• pp.19-24
• /
• 2016

최소오차 엔트로피 알고리듬(MEE)은 충격성 잡음 환경에서 성능이 우수한 것으로 알려져 있다. 이 논문에서는 충격성 잡음에 대한 강인성의 견지에서 MEE 알고리듬의 최적해와 특성을 연구하였다. 큰 오차 값의 영향을 경감하는 요인들과 최적 가중치의 움직임에 대한 분석을 통하여 MEE의 최적해가 충격성 잡음으로부터 안정적으로 유지되도록 하는 주된 역할은 크기 조정된 입력 엔트로피가 담당하고 있음이 밝혀졌다. 시뮬레이션 결과에서, MEE의 최적해는 MSE 성능기준의 최적해와 같은 값을 가짐을 보였다.

• 인터넷정보학회논문지
• /
• 제18권6호
• /
• pp.1-6
• /
• 2017

이 논문에서는 충격성 잡음환경에서 탁월한 성능을 보이는 CIPD 알고리즘에 대해, 오차에 대한 가우시안 커널로 입력이 보정된 MCI의 전력 추이를 가중치 갱신 방정식에 반영한 새로운 방식을 제안하였다. 제안한 알고리즘이 기존의 CIPD 알고리즘보다 우수한 성능을 가지는지 평가하기 위해, 각 알고리즘의 가중치 벡터 변화량이 얼마나 충격성 잡음에 강인한가를 충격성 잡음하에서 비교하였으며, 실험 결과에서 2배 이상의 정상상태 안정성 향상, 약 1.8배 빠른 수렴속도와 약 2dB 정도 더 낮은 최소 MSE 값을 나타냈다.

• 가정과삶의질연구
• /
• 제19권5호
• /
• pp.189-202
• /
• 2001

The purpose of this study was to investigate the effects of perceived parents-adolescent communication style on adoescent’s self-efficacy. The subjexts of this study were 625 students selected at random from first and second grade of high school in Daegu. A questionnaire was used as survey method. Factor analysis, MANOVA and cluster analysis for data analysis and Scheffe test for post-hoc analysis were employed. The man findings were as follows: Firs, there were significant differences in the degree of adolescent’s self-efficacy according to perceive father-adolescent communication style. In case that adolescents perceived their father’s communication style as reasonable, the degree of self-control, self-confidence and attribution were higher than those of other cases such as non-interferential or impulsive communication style. The adolescents who perceived the father’s communication style as reasonable showed higher preference of difficult task than those who perceived it as non-interferential style. The adolescents who perceived father’s communication style as reasonable and non-interferential showed higher attribution than those who perceived it as impulsive style. Second, there were significant differences in the degree of adolescent’s self-efficacy according to perceived mother-adolescent communication style. In case that adolescents perceived their mother’s communication style as reasonable, the degree of self-control was higher than that of other cases such as non-interferential and impulsive communication style. The adolescents who perceived their mother’s communication style as reasonable showed higher self-confidence than those who perceived as impulsive style.

• Journal of Information Display
• /
• 제9권1호
• /
• pp.1-5
• /
• 2008

Two new impulsive driving technologies for 120Hz liquid crystal display (LCD) panels are proposed to improve moving picture quality. One technology generates the dark frame using an adder and a shifter simply without using any look up tables (LUTs). It results in a cost effective impulsive scheme with motion picture quality comparable to that of high speed driving. The other is a backlight flashing method designed to avoid ghost images. The issue of ghost images caused by the slow response time of liquid crystal (LC) is solved by means of 120Hz overdriving and 120Hz backlight flashing. Using the perceived blur edge time (PBET) metric, measured moving picture response time (MPRT) values were 10.8ms and 4.4ms, respectively, while that of 120Hz high speed driving was 10.1ms.