• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.290-293
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• 1996

This paper presents an EMQ model which determines an optimal production run length in a deteriorating machine. It is assumed that a machine is subject to a random deterioration from an in-control state to an out-of-control state with an arbitrary distribution and thus producing constant proportion of defective items. An average cost function and an optimal production run length are determined. A mistake in previous model is found and discussed. A mistake in previous model is found and discussed. Numerical experiments are carried out to see the behavior of the proposed model depending on the cost factors as well as machine parameters, and some interesting behaviors are observed.

• 대한전기학회논문지
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• 제43권6호
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• pp.951-957
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• 1994

We present a new model for the series resistance of inverted-staggered amorphous silicon (a-Si) thin film transistors (TFT's) by employing the current spreading under the source and the drain contacts as well as the space charge limited current model. The calculated results based on our model have been in good agreements with the measured data over a wide range of applied voltage, gate-to-source and gate-to-drain overlap length, channel length, and operating temperature. Our model shows that the contribution of the series resistances to the current-voltage (I-V) characteristics of the a-Si TFT in the linear regime is more significant at low drain and high gate voltages, for short channel and small overlap length, and at low operating temperature, which have been verified successfully by the experimental measurements.

• 수산해양기술연구
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• 제48권1호
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• pp.51-58
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• 2012

As a basic study to improve hooking ability of long line fishing gear, which is widely used around Jeju-do coast, the researcher performed hooking experiment of parrot fish by manufacturing and installing 7 kinds of model long line fishing gears, whose thickness of branch line are different and 8 kinds of model long line fishing gear, whose length of branch line are different, in indoor circular aquarium, which is installed for the model experiment of thickness and length of branch line that are various by fishing implement and improper. The hooking rate depending on thickness and length of branch line was calculated and the effect of thickness and length of branch line on hooking rate was analyzed. Its results are as follows. When branch line was thin and long, high hooking rate appeared. In the scope of value setting, the relationship between thickness ($B_t$) of branch line and total hooking rate ($Th_r$) can be shown as following formula as. In the scope of value setting, the relationship between length ($B_t$) of branch line and total hooking rate ($B_t$) can be shown as $Th_r=-20.83B_t+26.04$. Through Pearson correlation analysis, the coefficient of correlation between thickness of branch line and hooking rate was -0.718. Therefore it showed significance in 0.01 significance level. Through Pearson correlation analysis, the coefficient of correlation between length of branch line and hooking rate was 0.431. Therefore it showed significance in 0.01 significance level.

• Computers and Concrete
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• 제12권2호
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• pp.187-209
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• 2013

This paper presents a study on the prediction of transfer length of 13 mm seven-wire prestressing steel strand in pretensioned prestressed concrete members with rectangular cross-section including several material properties and design and manufacture parameters. To this end, a carefully selected database consisting of 207 different cases coming from 18 different sources spanning a variety of practical transfer length prediction situations was compiled. 16 single input features and 5 combined input features are analyzed. A widely used feedforward neural regression model was considered as a representative of several machine learning methods that have already been used in the engineering field. Classical multiple linear regression was also considered in order to comparatively assess performance and robustness in this context. The results show that the implemented model has good prediction and generalization capacity when it is used on large input data sets of practical interest from the engineering point of view. In particular, a neural model is proposed -using only 4 hidden units and 10 input variables-which significantly reduces in 30% and 60% the errors in transfer length prediction when using standard linear regression or fixed formulas, respectively.

• 한국지진공학회논문집
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• 제19권2호
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• pp.75-83
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• 2015

The purpose of this study is to improve the previous damage evaluation model for RC members which is proposed by Igarashi[1] in 2010.The previous model was not confirmed by enough data of damage such as, residual crack length, width and area for exfoliation of concrete, etc. In addition, validation of the model is still insufficient. Therefore, experiment of a real-scale RC structure and experiment of RC columns using the high-strength concrete were conducted to gather the data of damage in RC members. The investigation has been conducted gathering the data not only additional experiments data but also existing data for modification of damage evaluation model. It has been investigated on changing damage in RC due to axial force ratio, shear reinforcement and shear span ratio. As a result, several problems were founded in the previous model, such as, hinge length($l_p$), spacing of flexural crack($S_{av,f}$), total width of flexural cracks regulated by maximum width of flexural crack($n_f$) and total width of shear cracks regulated by maximum width of shear crack($n_s$). New model is proposed and evaluated the damage properly.

• 대한치과기공학회지
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• 제38권3호
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• pp.151-156
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• 2016

Purpose: The dental implant should be enough to endure chewing load and it's required to have efficient design and use of implant to disperse the stress into bones properly. This study was to evaluate the stress distribution on a supporting bone by lengths and diameters of the implant fixture. Methods: The modeling and analysis of stress distribution was used for the simple molar porcelain crown model by Solidworks as FEM program. It was designed on applying with tightening torque of 20 Ncm of a abutment screw between a cement retained crown abutment and a fixture. The fixtures of experimental model used 10, 13mm by length and 4, 5mm by diameter. A external vertical loading on the two buccal cusps of crown and performed finite element analysis by 100 N. Results: The maximum von Mises stress(VMS) of all supporting bone models by fixture length and diameter were concentrated on the upper side of supporting compact bone. The maximum stress of each model under vertical load were 164.9 MPa of M410 model, and 141.2 MPa of M413 model, 54.3 MPa of M510 model, 53.6 MPa of M513 model. Conclusion: The stress reduction was increase of fixture's diameter than it's length. So it's effective to use the wider fixture as possible to the conditions of supporting bone.

• 대한전기학회논문지:전력기술부문A
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• 제48권8호
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• pp.1046-1053
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• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• Geomechanics and Engineering
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• 제35권1호
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• pp.13-27
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• 2023

The model production for large-scale (lateral length ≥ 2.0 m) capillary barrier (CB) model tests is time and cost-intensive. To address these limitations, the framework of a small-scale CB (SSCB) model test under the lateral no-flow condition has been established. In this study, to validate the experimental methodology of the SSCB model test, a series of seepage analyses on the SSCB model test and engineered slopes in the same and additional test conditions was performed. First, the seepage behavior and diversion length (L_D) of the CB system were investigated under three rainfall conditions. In the seepage analysis for the engineered slopes with different slope angles and sand layer thicknesses, the L_D increased with the increase in the slope angle and sand layer thickness, although the increase rate of the L_D with the sand layer thickness exhibited an upper limit. The L_D values from the seepage analysis agreed well with the results estimated from the laboratory SSCB mode test. Therefore, it can be concluded that the experimental methodology of the SSCB model test is one of the promising alternatives to efficiently evaluate the water-shielding performance of the CB system for an engineered slope.

• 대한토목학회논문집
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• 제30권5A호
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• pp.485-493
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• 2010

국내에서 개발된 이형 GFRP 보강근은 표면에 구축된 이형의 전단강도가 콘크리트의 전단강도 보다 상대적으로 작아 이형철근과 달리 이형 자체가 전단파괴되는 파괴모드를 보이는 것으로 확인된바 있다. 본 논문에서는 이형을 갖는 GFRP 보강근의 기본정착길이를 인발실험과 설계모델식과 해석적 엄밀식을 통해 고찰하였다. 실험결과, 동일조건하에서 파괴모드가 변화되는 임계정착길이가 이형철근은 직경의 15배, 이형 GFRP 보강근은 20배인 것으로 나타났다. 또한 실험결과를 ACI440.1R-03 설계모델식에 적용하여 분석한 결과, 충분한 횡구속이 수반된 경우 직경 9 mm의 이형 GFRP 보강근의 기본정착길이는 직경의 21배인 것으로 나타났다. 반면, ACI440.1R-06에 제시된 기본정착길이 모델은 실험결과에 비하여 너무 과대한 기본정착길이를 요구하는 것으로 나타났다. Cosenza 등(2002)의 모델은 실험결과에 비하여 더 적은 기본 정착길이를 요구하므로, 설계목적의 사용은 제한적인 것으로 판단되었다.

• 한국ITS학회 논문지
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• 제20권6호
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• pp.26-36
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• 2021

본 연구는 영상검지기에서 수집되는 정보를 활용하여 딥러닝 기반으로 대기행렬길이를 예측하는 모형을 개발하였다. 그리고 통계적 기법인 다중회귀 모형을 추정하여 평균절대오차와 평균제곱근오차의 두 지표를 이용하여 비교·평가하였다. 다중회귀분석 결과, 시간, 요일, 점유율, 버스 교통량이 유효한 변수로 도출되었고, 이 중에서 독립변수들의 종속변수에 대한 영향력은 점유율이 가장 큰 것으로 나타났다. 딥러닝 최적 모형은 은닉층이 4겹, Look Back이 6으로 결정되었고, 평균절대오차와 평균제곱근오차가 6.34와 8.99로 나타났다. 그리고 두 모형을 평가한 결과, 다중회귀 모형과 딥러닝 모형의 평균절대오차는 각각 13.65와 6.44, 평균제곱근오차는 각각 19.10과 9.11로 계산되었다. 이는 딥러닝 모형이 다중회귀 모형과 비교하여 평균절대오차가 52.8%, 평균제곱근오차는 52.3% 감소된 결과이다.