• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.35-42
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• 2007

This paper presents an INS(Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer(DRXL) manufactured by an epitaxially grown thick poly silicon process. The proposed DRXL system generates a differential digital output upon an applied acceleration, in which frequency transition is measured due to gap dependent electrical stiffness change. To facilitate the resonance dynamics of the electromechanical system, the micromachined DRXL device is packaged by using the wafer level vacuum sealing process. To test the DRXL performance, a nonlinear self-oscillation loop is designed based on the extended describing function technique. The oscillation loop is implemented using discrete electronic elements including precision charge amplifier and hard feedback nonlinearity. The performance test of the DRXL system shows that the sensitivity of the accelerometer is 24 Hz/g and its long term bias stability is about 2 mg($1{\sigma}$) with dynamic range of ${\sigma}70g$.

• 산업경영시스템학회지
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• 제35권2호
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• pp.98-105
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• 2012

This paper describes the Bayesian approach for reliability demonstration test based on the samples from a finite population. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the hypergeometric distribution is adopted as a likelihood function for a finite population. The conjugacy of the beta-binomial distribution and the hypergeometric distribution is shown and is used to make a decision about whether to accept or reject the finite population judging from a viewpoint of faulty goods. A numerical example is also given.

• 대한감각통합치료학회지
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• 제5권1호
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• pp.41-49
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• 2007

Objective: To evaluate the effectiveness of the home-based program composed of sensory diet for child with sensory modulation disorder. Method: The subject underwent the home-based program composed of sensory diet for 8 months. Evaluation tools we used are the Developmental Screening Test II(DDSTII) for developmental screening; the Short Sensory Profile(SSP), clinical observation and the clinical history record form for sensory integrative function; the Motor-Free Visual Perception Test(MVPT) and draw a person test for visual perception. Evaluation was executed before and after the program is provided. Results: The subject has showed remarkable improvement in developmental level, sensory integrative function and visual perceptual ability after went through the home-based program. Conclusion: The home-based program composed of sensory diet is effective for children with sensory modulation disorder when it is difficult to apply classical sensory integrative approach.

• The Korean Journal of Pain
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• 제9권1호
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• pp.244-247
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• 1996

A 67 year old male with postherpetic neuralgia complained of right anterior chest throbbing pain and also allodynia. We performed thoracic epidural block with 0.25% bupivacaine and 1% lidocaine. Oral carbamazepine and imipramine were also administred concomitantly. One month later, patient complained of fatigue, anorexia, pruritis, jaundice, and dark urine. Liver function test values were significantly elevated then. Therefore we removed the epidural catheter and ceased all medication. Liver function test values decreased rapidly after discontinuation of medication. Hepatitis might have developed as result of drugs administered and could have been prevented if the patient had been monitored with regular clinical laboratory follow up. The purpose of this case report is emphasize the importance of early regular laboratory test to detect any possible side effect that may occur by administration of drugs during treatment of chronic pain.

• Journal of the Korean Statistical Society
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• 제32권4호
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• pp.425-448
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• 2003

Meta-analysis refers to quantitative methods for combining results from independent studies in order to draw overall conclusions. We consider hierarchical models including selection models under a skewed heavy tailed error distribution proposed originally by Chen et al. (1999) and Branco and Dey (2001). These rich classes of models combine the information of independent studies, allowing investigation of variability both between and within studies, and incorporate weight function. Here, the testing for the skewness parameter is discussed. The score test statistic for such a test can be shown to be expressed as the posterior expectations. Also, we consider the detail computational scheme under skewed normal and skewed Student-t distribution using MCMC method. Finally, we introduce one example from Johnson (1993)'s real data and apply our proposed methodology. We investigate sensitivity of our results under different skewed errors and under different prior distributions.

• 한국농공학회지
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• 제35권4호
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• pp.106-118
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• 1993

The purpose of this study is to develop a multireservoir water balance model which may be used to evaluate rural water demands such as agricultural water, domestic water, industrial water and livestock water and to determine effective storage of reservoir. The model was verified to compare the observed reservoir release data with the simulated reservoir release data of the existing Munsan and Dongbu reservoirs located in the Gisan rural district for 3 years('87~'89). For model application, the effective storages of existing reservoirs(Munsan & Dongbu) were evaluated for 10-year frequency drought and that of newly planned reservoirs(Kumbok & Kudong) were determined for 10-year frequency drought. In addition, the behavior of effective storages for existing reservoirs were analyzed in the case of introducing new reservoirs in the existing system.

• Tribology and Lubricants
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• 제15권2호
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• pp.141-149
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• 1999

Fracture, fatigue and wear characteristics of Al-Si alloy used for compressor are experimentally studied. Plane strain fracture toughness test is carried out using three point bending specimen. Fatigue test is performed under constant loading condition and wear test is carried out as a function of sliding velocity and applied load. To obtain the crack propagation characteristics and wear mechanism of Al-Si alloy, fracture and worn surfaces are investigated using SEM. It is verified that fracture and fatigue strength of Al-Si alloy are improved by the fine microstructure of alloy. The wear behavior and specific wear amount of Al-Si alloy are not dependent on the microstructure but on a function of the silicon content. Anodizing on the surface of Al-Si alloy, surface hardness and wear characteristics are improved.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.109-118
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of field test results and simulation results of the ADAMS/Car demonstrates the validity of the proposed functional suspension modeling method. This model is suitable for real-time vehicle dynamics analysis.

• Transactions on Electrical and Electronic Materials
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• 제10권1호
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• pp.5-8
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• 2009

The reliability of multilayer ceramic capacitor with active thin dielectric layer was investigated by highly accelerated life test at various stress condition. The distribution of multilayer ceramic capacitor failure times is plotted as a function of time from Weibull distribution function. According to the test result, voltage acceleration factor is obtained from 2.24 to 2.96. The acceleration by temperature is much higher than other values of active thick dielectric layer. It is clear that median time to failure is affected by the stress voltage for high volumetric efficiency ceramic capacitors with active thin dielectric layer. The degradation under stress of voltage involves electromigration and accumulation of oxygen vacancy at Ni electrode interface of cathode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.100-102
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• 2005

This paper is purpose to introduce the database management program of insulation tests for high voltage rotating machines. KEPRI has carried out insulation tests for high voltage equipment since 1998, the number of tests grow larger every year. It is difficult to manage the numerous test results, so we developed the insulation diagnostic database program. The features of this program are an easy-search test result and making a graph of AC, tan${\Delta}$ test. the most useful function is the trend management. Using the trend function, we can find the aging deterioration for high voltage machines easily.