• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.259-262
• /
• 2002

This paper provides the experimental verification of a non-destructive time domain approach to examine structural damage. Time histories of the vibration response of structure were used to identify the presence of damage. Damage in a structure cause changes in the physical coefficients of mass density, elastic modulus and damping coefficient. This paper examines the use of beam like structures with PVDF sensor and PZT actuator to perform identification of those physical parameters, and hence to detect the damage. Experimental results are presented from tests on cantilevered composite beams damaged at different location and with damage of different dimensions. It is demonstrated that the method can sense the presence of damage, and characterize the damage to a satisfactory precision.

• Communications for Statistical Applications and Methods
• /
• 제12권3호
• /
• pp.643-652
• /
• 2005

It has been known that the exponentiated exponential distribution can be used as a possible alternative to the gamma distribution or the Weibull distribution in many situations. But the maximum likelihood method does not admit explicit solutions when the sample is multiply censored. So we derive the approximate maximum likelihood estimators for the location and scale parameters in the exponentiated exponential distribution that are explicit function of order statistics. We also compare the proposed estimators in the sense of the mean squared error for various censored samples.

• 대한수학회지
• /
• 제44권6호
• /
• pp.1397-1415
• /
• 2007

We consider an inverse heat conduction problem(IHCP) in a quarter plane which appears in some applied subjects. We want to determine the heat flux on the surface of a body from a measured temperature history at a fixed location inside the body. This is a severely ill-posed problem in the sense that arbitrarily "small" differences in the input temperature data may lead to arbitrarily "large" differences in the surface flux. A semi-discrete central difference scheme in time is employed to deal with the ill posed problem. We obtain some error estimates which also give the information about how to choose the step length in time. Some numerical examples illustrate the effects of the proposed method.

• 대한간호학회지
• /
• 제26권1호
• /
• pp.138-147
• /
• 1996

Although sensory deficits caused by stroke have been occasionally reported, dysfunctions of discriminative sensation have seldom been studied in patients with strokes. With the use of specifically designed methods, discriminative sensations including texture discrimination and position sense were tested in 67 patients with acute unilateral stroke. Thirty-two age and sex-matched healthy subjects were used as controls. Impaired discriminative sensation was common in patients with unilateral stroke (detected in 57 out of the 67 patients) regardless of the lesion location except for patients with lateral medullary stroke. Proprioceptive discriminative sensation remained intact in all except for three out of 25 patients who were initially diagnosed as having pure motor stroke on the bases of conventional sensory tests. However, tactile discriminative sensation remained intact in only 17 out of 25 patients. Discriminative sensory disturbances are common in patients with unilateral stroke even in those with intact sensory function on routine examination. The subtle disturbances of this sensation may explain, at least in part, the clumsiness of the patients that is not readily explained by conventional neurological tests.

• Journal of the Korean Data and Information Science Society
• /
• 제18권4호
• /
• pp.1081-1091
• /
• 2007

In this paper, we derive the approximate maximum likelihood estimators of the scale parameter and location parameter in an exponentiated logistic distribution based on multiply Type-II censored samples. We compare the proposed estimators in the sense of the mean squared error for various censored samples. We also propose and compare the estimators of the reliability function by using the proposed estimators of the parameters.

• Journal of the Korean Data and Information Science Society
• /
• 제21권5호
• /
• pp.935-944
• /
• 2010

In this paper, we develop the noninformative priors for the reliability in a stress-strength model where a strength X and a stress Y have independent exponential distributions with different scale parameters and a common location parameter. We derive the reference priors and prove the propriety of joint posterior distribution under the general prior including the reference priors. Through the simulation study, we show that the proposed reference priors match the target coverage probabilities in a frequentist sense.

• Coupled systems mechanics
• /
• 제3권3호
• /
• pp.291-304
• /
• 2014

Paper discusess a dynamic engineering problem of a mass attached to a pendulum sliding along a cable. In this problem the pendulum mass and the cable are coupled together in a model described by a system of differential algebraic equations (DAE). In the paper we have presented formulation of the system of differential equations that models the problem and determination of the initial conditions. The developed model is general in a sense of free choice of support location, elastic cable properties, pendulum length and inclusion of braking forces. Examples illustrate and validate the model.

• 한국항해학회지
• /
• 제22권4호
• /
• pp.15-19
• /
• 1998

This paper concerns a bulk or semibulk cargo ship scheduling problem with a single loading port. This type of ship scheduling problem is frequently needed in real world for carrying minerals or agricultural produce from a major single production zone to many destinations scattered over a large area of the world. The first optimization model for this problem was introduced by Ronen (1986) as a nonlinear mixed integer program. The model developed in this paper is an improvement of his model in the sense that nonlinearities and numerous unnecessary integer variables have been eliminated. By this improvement we could expect real world instances of moderate sizes to be solved optimal solutions by commercial integer programming software. Similarity between the ship scheduling model and the capacitated facility location model is also discussed.

• 한국가정과학회지
• /
• 제7권1호
• /
• pp.81-99
• /
• 2004

This study examined one room(studio apartment) residential deweller's housing behavior and housing need, and the relationship between the sense of housing values and housing satisfaction of one-room residence, The study surveyed 302 one-room residents in Busan city. The researcher modified, complimented, and used the previous researches on housing values and housing satisfaction. The analysis of the data used SPSS Win 10.0 program. The results of the research can be summarized as follows: 1. The motive of choosing one-room residence was mainly the closeness to the school or work, Jeonse(Rent with a one-room deposit) was more common than ownership, and the size is one-room residence was 10 to 15 Pyeong. 2. Among the five housing values of one-room residence dwellers, that is, amenity, indoor and outdoor environment, economy/convenience, convenience in transportation, and the interior functionality, the convenience in transportation was ranked highest, and the indoor and out door environment and economy/convenience followed. 3. The housing satisfaction of one-room residents was highest in location, and also high in the safety and the security or privacy, and the convenience of inside facility.

• 대한전기학회논문지
• /
• 제34권6호
• /
• pp.213-219
• /
• 1985

Superconducting Magnetic Energy Storage (SMES) system can be used for power system stabilization by absorbing or discharging active and reactive power through thyristor-comtrolled converters. In this paper, we have proposed a control algorithm that the active and reactive powers of SMES are simultaneously controlled to increase power system dynamic stability. The proposed method was applied to one machine-infinite and three machines and three load model systems. And it has been shown that the proposed algorithm is more effective in power system stabilization than the conventional one that only the active power of SMES is controlled. Eigenvalue sensitivity analysis method is introduced to estimate the optimal location of SMES in the sense of the power system oscillation mode.