• Journal of the KSME
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• v.31 no.8
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• pp.735-744
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• 1991

확산모델과 파모델의 결과에 있어 큰 차이가 일어나는 경우를 요약하면 다음과 같다. 1) 과도기 간이 짧다. 2) 작동온도가 아주 낮다. 3) 온도구배가 상당히 크다. 이때3)의 경우는 서로 다른 물질들이 접촉된 경우 또는 높은 열유속이 있는 경우 또는 얇은 표면층 등을 갖는 문제들의 공 통적인 특징이다. Non-Fourier 열전도 문제를 이용해 온도 분포를 예측해야 하는 실제적인 몇 가지 예를 살펴 보면 레이저 기술 또는 절대온도 영(zero)에 접근하는 온도에서의 액체 헬륨을 다루는 저온공학연구 또는 1/$10^{6}$Inch 정도의 표면조도가 관심사인 정밀공학 등을 들 수 있다. 또한 상당히 높은 강도의 열원이 작용될 때 고체에서의 크랙이나 보이드(void) 같은 국소 결함은 확산거동이 나타나기에 요구되는 시간보다 짧은 시간 구간에서 발생되어질 수 있으며, 크랙발생의 방향과 같은 것들은 hyperbolic 모델에의해 예측되어져야만 한다. 특히 움직이는 열원 또는 propagating crack tip을 갖는 경우에 그들 주위에서의 온도장을 규정짓는 가장 중요한 변 수는 열마하수 M이며, 아음속에서 초음속 영역으로 천이될 때 물리적 양들의 변화에 있어서 일어나는 현상들은 열충격의 형성에 기인하는데 이러한 현상들은 확산 모델로서는 예측될 수 없는 특징들이다. 이상에서 살펴볼 때 non-Fourier 모델에 대해 관심을 기울일 필요가 있다고 사료된다.

• Progress in Medical Physics
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• v.15 no.2
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• pp.84-93
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• 2004

Stereotactic radiosurgery (SRS) is a technique that delivers a high dose to a target legion and a low dose to a critical organ through only one or a few irradiations. For this purpose, many mathematical methods for optimization have been proposed. There are some limitations to using these methods: the long calculation time and difficulty in finding a unique solution due to different tumor shapes. In this study, many clinical target shapes were examined to find a typical pattern of tumor shapes from which some possible ideal geometrical shapes, such as spheres, cylinders, cones or a combination, are assumed to approximate real tumor shapes. Using the arrangement of multiple isocenters, optimum variables, such as isocenter positions or collimator size, were determined. A database was formed from these results. The optimization procedure consisted of the following steps: Any shape of tumor was first assumed to an ideal model through a geometry comparison algorithm, then optimum variables for ideal geometry chosen from the predetermined database, followed by a final adjustment of the optimum parameters using the real tumor shape. Although the result of applying the database to other patients was not superior to the result of optimization in each case, it can be acceptable as a plan starling point.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.2
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• pp.67-73
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• 2003

The purpose of this study is to evaluate seismic performance of reinforced concrete bridge columns under varying axial force. A computer program, named RCAHEST(reinforced concrete analysis in higher evaluation system technology), for the analysis for reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuity in deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel and concrete. The proposed numerical method for seismic performance evaluation of reinforced concrete bridge columns under varying axial force is verified by comparison with reliable experimental results.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.467-473
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• 2002

The purpose of this study is to investigate the inelastic behavior and ductility capacity of reinforced concrete frame subjected to cyclic lateral load and to provide result for developing improved seismic design criteria. A computer program named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology) for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. The strength increase of concrete due to the lateral confining reinforcement has been taken into account to model the confined concrete. In boundary plane at which each member with different thickness is connected local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel. The proposed numerical method for the inelastic behavior and ductility capacity of reinforced concrete frame subjected to cyclic lateral load is verified by comparison with reliable experimental results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.396-402
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• 2021

As the world is trying to establish smart city, unmanned vehicle control systems are being widely used. This paper writes about an unmanned parking control system that uses an adaptive background image modeling method, suggesting the method of updating the background image, modeled with an adaptive Gaussian mixture model, in both global and local way according to the moving object. Specifically, this paper focuses on suggesting two methods; a method of minimizing the influence of a moving object on a background image and a method of accurately updating the background image by quickly removing afterimages of moving objects within the area of interest to be monitored. In this paper, through the implementation of the unmanned vehicle control system, we proved that the proposed system can quickly and accurately distinguish both moving and static objects such as vehicles from the background image.

• Journal of the Korean earth science society
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• v.32 no.3
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• pp.249-264
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• 2011

A multi-Gaussian kriging approach extended to space-time domain is presented for uncertainty modeling as well as time-series mapping of environmental variables. Within a multi-Gaussian framework, normal score transformed environmental variables are first decomposed into deterministic trend and stochastic residual components. After local temporal trend models are constructed, the parameters of the models are estimated and interpolated in space. Space-time correlation structures of stationary residual components are quantified using a product-sum space-time variogram model. The ccdf is modeled at all grid locations using this space-time variogram model and space-time kriging. Finally, e-type estimates and conditional variances are computed from the ccdf models for spatial mapping and uncertainty analysis, respectively. The proposed approach is illustrated through a case of time-series Particulate Matter 10 ($PM_{10}$) concentration mapping in Incheon Metropolitan city using monthly $PM_{10}$ concentrations at 13 stations for 3 years. It is shown that the proposed approach would generate reliable time-series $PM_{10}$ concentration maps with less mean bias and better prediction capability, compared to conventional spatial-only ordinary kriging. It is also demonstrated that the conditional variances and the probability exceeding a certain thresholding value would be useful information sources for interpretation.

• The Journal of Pediatrics of Korean Medicine
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• v.15 no.1
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• pp.255-259
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• 2001

본 연구는 운비요법(運脾療法)이 脾虛 동물모델 Rat의 흡수기능에 미치는 영향을 관찰하기 위한 것이다. 이혈평(利血平)으로 Rat의 비허(脾虛) 상태를 유발시킨 다음 최초로 비허(脾虛) 상태에서의 혈청 중 Zn 및 소장검막의 구조변화를 관찰하였고, 임상적으로는 소아의 편식증, 영양실조성 빈혈, 반복적인 소아감염증상(RRI) 등에 대한 운비법(運脾法)의 효과를 관찰하였다. 청결상태로 관리한 체중이 220-240g의 Wester계 웅성 Rat 15마리를 무작위로 각 5마리씩 정상군, 비허군(脾虛群), 중약투여군에 배분하여 3group으로 나누었다. 비허군과 중약투여군에는 모두 이혈평(利血平)을 소량으로 서서히 투여하였고, 중약투여군에는 동시에 중약 시럽(당장(糖漿))을 경구투여시켜 3주간 실험관찰하였다. 결과 : (1) 섭취량(g/일/마리) : 정상군은 22.1, 비허군(脾虛群)은 9.04, 중약투여군은 17.3으로 각각 나타났다. (2) 체중(g) : 정산군은 $284.2{\pm}32.51$, 비허군(脾虛群)은 $193{\pm}15.26$, 중약투여군은 $231.8{\pm}22.76$으로 각각 측정되었다. (3) 혈청 중 Zn함량(ug/1) : 정상군 $1911{\pm}993.8$, 비허군(脾虛群) $1094{\pm}249.4$, 중약투여군 $2599.8{\pm}1282.1$로 각각 측정되었다. 이와 같은 결과에서 중약투여군의 섭취량, 체중 및 혈청 중 Zn의 함량 모두 대조군에 비교하여 현저하게 개선되었음을 알 수 있다. (4) 소장의 정막구조 : 비허군(脾虛群)은 정상군에 비해 소장의 점막이 현저하게 얇고 융모상 돌기가 오그라들며 퇴화되는 변화를 나타냈고, 일부 융모상 돌기 끝의 상피세포는 국소적 괴사 및 퇴행성 변화를 일으키기도 하였다. 중약투여군은 이에 비해 소장점막이 거의 정상에 가깝게 회복되었다. 결론 : 운비요법(運脾療法)은 비허(脾虛) 동물모델에 대한 흡수기능의 개선에 효과가 있음을 본 실험에서 입증할 수 있었다.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.3
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• pp.31-40
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• 2002

The purpose of this study is to investigate the seismic behavior of RC bridge piers and to provide the data for developing improved seismic design criteria. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST(reinforced concrete analysis in higher evaluation system technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. n boundary plane at which each member with different thickness is connected, local discontinuity in deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel and concrete. In the companion paper, the proposed numerical method for seismic damage evaluation of RC bridge piers is verified by comparison with the reliable experimental results.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.9
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• pp.351-360
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• 2018

The LWR (Locally Weighted Regression) model, which is traditionally a lazy learning model, is designed to obtain the solution of the prediction according to the input variable, the query point, and it is a kind of the regression equation in the short interval obtained as a result of the learning that gives a higher weight value closer to the query point. We study on an incremental ensemble learning approach for LWR, a form of lazy learning and memory-based learning. The proposed incremental ensemble learning method of LWR is to sequentially generate and integrate LWR models over time using a genetic algorithm to obtain a solution of a specific query point. The weaknesses of existing LWR models are that multiple LWR models can be generated based on the indicator function and data sample selection, and the quality of the predictions can also vary depending on this model. However, no research has been conducted to solve the problem of selection or combination of multiple LWR models. In this study, after generating the initial LWR model according to the indicator function and the sample data set, we iterate evolution learning process to obtain the proper indicator function and assess the LWR models applied to the other sample data sets to overcome the data set bias. We adopt Eager learning method to generate and store LWR model gradually when data is generated for all sections. In order to obtain a prediction solution at a specific point in time, an LWR model is generated based on newly generated data within a predetermined interval and then combined with existing LWR models in a section using a genetic algorithm. The proposed method shows better results than the method of selecting multiple LWR models using the simple average method. The results of this study are compared with the predicted results using multiple regression analysis by applying the real data such as the amount of traffic per hour in a specific area and hourly sales of a resting place of the highway, etc.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.251-256
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• 2020

In recent years, digital technology has been developed in dentistry, which denture frameworks can be manufactured using DMLS (Direct Metal Laser Sintering) technique. A traditional impression method can be replaced by oral scanning and wax pattern production process can be achieved by the use of CAD/CAM techniques. The designed STL files can be sent to DMLS devices to fabricate final components of removable partial dentures (RPD). The advantages of digital dentistry are concision and precision. In this case study, a fracture of occlusal rests providing support and indirect retention was repaired by DMLS and laser welding techniques. It shows satisfactory results in adaptation accuracy and functional properties of the repaired denture.