• Smart Structures and Systems
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• 제26권6호
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• pp.735-751
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• 2020

Identification of structure parameters is crucial in Structural Health Monitoring (SHM) context for activities such as model validation, damage assessment and signal processing of structure response. In this paper, guided waves generated by piezoelectric transducers are used for in-situ and non-destructive structural parameter estimation based on Bayesian approach. As Bayesian approach needs iterative process, which is computationally expensive, this paper proposes a method in which an analytical model is selected and developed in order to decrease computational time and complexity of modeling. An experimental set-up is implemented to estimate three target elastic and geometrical parameters: Young's modulus, Poisson ratio and thickness of aluminum and steel plates. Experimental and simulated data are combined in a Bayesian framework for parameter identification. A significant accuracy is achieved regarding estimation of target parameters with maximum error of 8, 11 and 17 percent respectively. Moreover, the limitation of analytical model concerning boundary reflections is addressed and managed experimentally. Pulse excitation is selected as it can excite the structure in a wide frequency range contrary to conventional tone burst excitation. The results show that the proposed non-destructive method can be used in service for estimation of material and geometrical properties of structure in industrial applications.

• 비파괴검사학회지
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• 제30권2호
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• pp.126-131
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• 2010

본 연구에서는 유도초음파를 이용하여 다양한 온도에서 사용되어지는 항공기 복합재료의 건전성에 대하여 평가하였다. 항공기가 지상과 비행고도에서 운행할 때의 온도편차나, 반복되어지는 열주기 횟수와 같이, 항공기가 운행되어지는 온도와 관련하여 복합재료의 건전성에 결정적인 영향을 미치는 요소에 관한 연구는 항공기 안전에 있어서 매우 중요한 요소가 되고 있다. 본 연구에서는 유도초음파를 이용하여 항공기의 운행환경과 유사한 환경 하에서 열피로가 가해진 항공기의 복합재료 시편을 평가하였다. 유도초음파의 분산선도 곡선은 서로 다른 열피로가 가해진 시편에 대한 민감성을 나타내기 위해 최적의 모드를 선택하는데 사용되었다. 현재 제시된 접근법 또한 항공기의 건전성을 평가하는데 있어서 하나의 도구로 구현될 수 있다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3485-3488
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• 2012

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.765-774
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• 2008

In this paper, we derive the approximate maximum likelihood estimators(AMLEs) and maximum likelihood estimator of the scale parameter in a triangular distribution based on progressive Type-II censored samples. We compare the proposed estimators in the sense of the mean squared error through Monte Carlo simulation for various progressive censoring schemes.

• Journal of the Korean Data and Information Science Society
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• 제19권3호
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• pp.951-957
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• 2008

We derive some approximate maximum likelihood estimators(AMLEs) and maximum likelihood estimator(MLE) of the scale parameter in the half-triangle distribution based on progressively Type-II censored samples. We compare the proposed estimators in the sense of the mean squared error for various censored samples. We also obtain the approximate maximum likelihood estimators of the reliability function using the proposed estimators. We compare the proposed estimators in the sense of the mean squared error.

• 한국환경보건학회지
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• 제24권2호
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• pp.145-150
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• 1998

This study was carried out to investigate the loss amount of collection at the different of precipitatation time, high voltage and gas speed. This work has focused on the dependence of the collection efficiency in the collector zone with gas speed and high voltage. This advanced Model is developed by research of the different parameter as the conventionnal modem of study. In order to investigate collection efficiency of electrostatic precipitator, the loss amount of knocking was measured with Monitek-Treubung and the particle size was analyzed by He-Ne laser diffraction spectroscopy.

• 보건의료산업학회지
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• 제10권3호
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• pp.113-122
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• 2016

Objectives : This study analyzed the influencing relationship among oral health belief, prevention of oral diseases, and quality of life subject in adults over 20 years of age. Methods : This study enrolled 237 participants who visited Y hospital located in the Gyeongnam district as the final subjects for the analysis. From the collected data, multiple regression analysis was conducted to identify the relative influence of oral health belief on each parameter using SPSS 18.0. Results : Based on the regression analysis results, it was found that the factor in oral health belief with the strongest influence on the intention to prevent oral disease was importance. The behavior for prevention of oral disease was influenced by sensitivity, and the quality of life was affected by self-efficacy. Conclusions : These results, suggest that in order to promote oral health in adults, continuous support from oral health professionals is required to make patients recognize the importance and the sensitivity of oral health and reduce sensitivity.

• Journal of Nutrition and Health
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• 제26권9호
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• pp.1033-1048
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• 1993

This study was designed to describe the effect of the protein quality at different intake level of protein on the protein metabolism in the whole body of growing pigs with a simulation model. Varying to the protein level in feeds, four simulations were conducted. The feed protein level, represented as proportions of digestible protein to the metabolic energy (DP/ME, g/MJ), were 6-8, 11-13, 17-19, and 23-25 DP/ME, respectively. Two protein quality and six weeks of growth time were used at each simulation. The objective function for the simulations was protein deposition in the whole body, which was calculated from the experimental results. The parameters in the simulation were determined by the parameter estimation technique. The results obtained from the simulation were as follows: The protein synthesis and breakdown rates(g/day) in the whole body was increased with the increase of protein quality only at lower or required level of protein intake. They showed a parallel behavior in the course of growth, irrespective of quality and level of feed protein intake. The simulated protein deposition and protein synthesis showed a linear relationship between them at different protein quality and level. The affinity parameter showed a linear relationship between them at different protein quality and level. The affinity parameter showed that arginine, tryptophan and isoleucine were more efficient in the stimulation ofbody protein synthesis. Lysine and phenylalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, pheyalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, phenyalanine+tyrosine, and methionine+cystine were oxidized in larger magnitude than lysine and threonine. The oxidation parameter of most amino acids increased with the increase of protein intake beyond the requirement level, but not any more at highest protein intake level. Finally it was found that the improvement of feed protein quality at the lower or required level of protein intake increase protein deposition through a parallel increase of protein synthesis and breakdown.

• Journal of Preventive Medicine and Public Health
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• 제42권4호
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• pp.215-222
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• 2009

Objectives : Vigorous physical activity is a well-known method to promote people s health. This research aims to investigate whether perceived neighborhood characteristics affect vigorous physical activity among adult Seoul residents (aged 19 to 64). Methods : Utilizing the 2005 Seoul Citizens Health Indicators Survey data, this study estimates the probability of vigorous physical activity. Particular attention is given to the effects of three perceived neighborhood characteristics satisfaction with relationship to the neighborhood, satisfaction with park and recreational facilities, and satisfaction with public security). Logistic regression models are analyzed separately by gender for the parameter estimation. Results : Vigorous physical activity is positively associated with three perceived neighborhood characteristics for women, while neither significant nor substantive association is found for men. Conclusions : As vigorous physical activity among Seoul citizens is differentially affected by perceived neighborhood characteristics and by gender, a different approach will be needed to increase vigorous physical activity of men and women in Seoul.

• 호남수학학술지
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• 제36권1호
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• pp.131-139
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• 2014

We present a theoretical study that assesses the persistence of obesity. The basic reproductive number for the model is computed, and its sensitivity on some parameter values is explored. This may be of interest to public health authorities.