• 한국정보처리학회논문지
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• 제4권1호
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• pp.177-183
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• 1997

비 중심t분포의 누적함수는 두 정규모집단에서 모평균의 동일성 검정에서 검정력 계산 및 모 평균에 대한 표준편차의 비에 대하여 신뢰구간을 계산할 때 요구된다. 본 논문에서는 비중심t분포의 누적함수 계산에 신경망 이론을 적용하였다. 신경망은 다 층 퍼셉트론이며 학습과정은 역전파 학습알고리즘이다. Fisher가 제시한 확률값과 신 경망이론에 의하여 계산한 결과를 비교하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.767-772
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• 2002

Using the diffusion cell, a experimental study on the nitrogen permeability was performed with the various thickness of concrete. This is important with relating to the carbonation study because the study of $CO_2$ diffusivity needs to use thin concrete specimen. Experimental results show that the nitrogen permeability is few affected by concrete specimen's thickness. But, specimens with 1cm thickness have a high permeability and deviation relatively. Also, specimens with w/c ratio 0.40 have a low permeability than 0.58. Consequently, the 3cm thickness is the better stable than others but the 1cm thickness specimens will be stable in case having a lot of specimens.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 추계 학술대회
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• pp.199-204
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• 2006

ANOVA is widely used for measurement system analysis. It assumes that the measurement error is normally distributed, which may not be seen in some industrial cases. In this study, the estimates of the measurement system variability and PTR (precision-to-tolerance ratio) are obtained by using weighted standard deviation for the case where the measurement error is non-normally distributed. The Standard Bootstrap method is used for estimating confidence intervals of measurement system variability and PTR. The point and confidence interval estimates for the cases with normally distributed measurement error are compared to those with non-normally distributed measurement errors through computer simulation.

• Journal of Mechanical Science and Technology
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• 제14권3호
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• pp.314-319
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• 2000

Back-face strain compliance (BFS compliance) for the four-point bend specimen has been calibrated for various crack length ratios. Finite element technique was employed to simulate four-point loading and calculate back-face strain of the bend specimen. The numerically determined strain variation along the back face indicates that the sensitivity to gage placement increases with crack length and back-face strain at the gage length less than O.2W, where W is the width of the bend specimen, can be measured within 5% deviation of the maximum BFS. Non-dimensional back-face strain compliance, -E'BCW, was calibrated with FE analysis and experiment. The experimentally determined compliance indicates good agreement with the numerical compliance and can be expressed as a function of crack length ratio.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.198-206
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• 1999

An automobile outside rear view mirror system has been analyzed and designed to reduce vibration with a finite element model. model analysis is conducted for the calculation of natural frequencies. harmonic analysis is utilized to estimate the displacements of the glass surface under dynamic loads. The model is verified with the vibration experiment of the parts and the assembled body. The structure of the mirror system is optimized for the robustness defined by the Taguchi concept. At first, many potential design variables are defined. Final design variables are selected based on the amount of contribution on the objective function. That is, sensitive variables are chose. The SN ratio in the Taguchi method is replaced by an objective function with the mean and the standard deviation of the quality characteristic. The defined objective function is appropriate in the structural design in that the vibration displacements are minimized while the robustness is improved.

• 에너지공학
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• 제22권2호
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• pp.205-210
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• 2013

Cycle-to-cycle variation has long been recognized as limiting the range of operating conditions of spark ignition engines, in particular, under lean and highly diluted operation conditions. At a part load, some of the cycles tend to knock, while others may have incomplete combustion by the time the exhaust valve opens. An experimental study has been performed in order to evaluate the relative contribution of several relevant parameters on the cyclic variability in spark ignition engines. In general, the stability of engine operation is improved with fuel injector according to the optimal injection timing, but the stability of engine operation at idle is not improved compared with a practical gasoline engine. In this study, we investigated the relationship of the effect of operating conditions for the stability at low speed and load.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.65-72
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• 2002

The closed cycle diesel system is operated in closed circuit system where there is non air breathing with working fluid consists of combination of oxygen, argon and recycled exhaust gas far obtaining underwater or underground power sources. Experimental apparatus using the MTU8V183SE92 high pressurized engine adapted for closed cycle running, capable of operating at the system pressure of maximum 5 bar is constructed with ACAP as data acquisition system in order to operate equally in the open cycle in surface or the closed cycle in submerged conditions. The general features and the characteristics of combustion of HP(high pressure) diesel engine, specially designed and manufactured only for CCDE, are investigated. The test results of performance of HP diesel engine in closed cycle system are presented with respect to power and boost pressure and compared with those of low pressure diesel engine. The oxygen concentration and specific heat ratio are investigated with its deviation

• Structural Engineering and Mechanics
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• 제66권4호
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• pp.543-555
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• 2018

Fiber Reinforced Polymer (FRP), which has a high strength to weight ratio, are now regularly used for strengthening of deficient reinforced concrete (RC) structures. While various researches have been conducted on FRP strengthening, an area that still requires attention is predicting the debonding failure load of prestressed FRP strengthened RC beams. Application of prestressing increases the capacity and reduces the premature failure of the beams largely, though not entirely. Few analytical methods are available to predict the failure loads under flexure failure. With this paucity, this research proposes a method for predicting debonding failure induced by intermediate crack (IC) for prestressed FRP-strengthened beams. The method consists of a numerical study on beams retrofitted with prestressed FRP in the tension side of the beam. The method applies modified Branson moment-curvature analysis together with the global energy balance approach in combination with fracture mechanics criteria to predict failure load for complicated IC-induced failure. The numerically simulated results were compared with published experimental data and the average of theoretical to experimental debonding failure load is found to be 0.93 with a standard deviation of 0.09.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권11호
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• pp.786-792
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• 2004

A wavelet based ECG data compression has become an attractive and efficient method in many mobile tele-cardiology applications. But large data size required for high compression performance leads a serious delay. In this paper, new wavelet compression method with minimum delay is proposed. It is based on deciding the type and compression ratio(CR) of block organically according to the standard deviation of input ECG data with minimum block size. Compression performances of the proposed algorithm for different MIT ECG Records were analyzed comparing other ECG compression algorithm. In addition to the processing delay measurement, compression efficiency and reconstruction sensitivity to error were also evaluated via random noise simulation models. The results show that the proposed algorithm has both lower PRD than other algorithm on same CR and minimum time in the data acquisition, processing and transmission.

• 대한치과교정학회지
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• 제16권1호
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• pp.155-165
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• 1986

Recently, straight-wire appliance is widely used with great concern in clinical orthodontic field. The purpose of this study was to collect the information of the straight-wire appliance and to determine the crown inclination in clinical orthodontics. The author analyzed the study model of 78 individuals with normal occlusion. The obtained results were as follows. 1. Mean, maximum value, minimum value and standard deviation of crown inclination of upper and lower teeth were obtained. 2. The lingual crown inclination of upper tooth had constant value from first premolar through second molar, the lingual crown inclination of lower tooth progressively increased from canine through second molar. 3. As Howes' ratio was decreased, the crown inclination of upper incisors was increased. 4. Narrowing the upper arch, the crown inclination of upper incisors was increased.