• Structural Engineering and Mechanics
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• 제11권4호
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• pp.373-392
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• 2001

The main idea behind the paper is to present two alternative methods of homogenization of the heat conduction problem in composite materials, where the heat conductivity coefficients are assumed to be random variables. These two methods are the Monte-Carlo simulation (MCS) technique and the second order perturbation second probabilistic moment method, with its computational implementation known as the Stochastic Finite Element Method (SFEM). From the mathematical point of view, the deterministic homogenization method, being extended to probabilistic spaces, is based on the effective modules approach. Numerical results obtained in the paper allow to compare MCS against the SFEM and, on the other hand, to verify the sensitivity of effective heat conductivity probabilistic moments to the reinforcement ratio. These computational studies are provided in the range of up to fourth order probabilistic moments of effective conductivity coefficient and compared with probabilistic characteristics of the Voigt-Reuss bounds.

• 한국조경학회지
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• 제29권5호
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• pp.20-27
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• 2001

The purpose of this study is to investigate and compare the validity and the reliability of the visual simulation method using the internet. For this. the evaluation of the artificial and natural landscape through the medium of color slides are compared with the internet survey. Data is analysed through the comparison of t-test between the two media by landscape type, and spatial image is analysed by factor analysis algorithm. Principle component analysis using Varimax Method is applied for extraction and factor rotation respectively. The results of this study can be summarized as follows; There are no statistical differences between the two methods with artificial and natural landscape in the total data that included second tests. Factors covering the spatial image are found to be \`aesthetic\`, \`spatial shape\`, and \`familiarity\`. Total variance is obtained as 66.4%. There are no statistical differences between the two methods in 2/3 of the cases. In the case of far view of artificial landscape, the results of the t-test show that the two methods are exactly the same. Especially in the case of the artificial far landscape shows no difference of all factors between two methods. There are no differences between first and second tests of the same media and the same landscape type. And it shows the reliability of this method. These results suggest that the probability that the internet can be used as a medium of landscape evaluation and gathering information on anyone\`s landscape image. Simulation techniques with the internet survey method should be further developed for practical application.

• 대한임베디드공학회논문지
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• 제16권5호
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• pp.209-214
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• 2021

Panoptic segmentation, which is now widely used in computer vision such as medical image analysis, and autonomous driving, helps understanding an image with holistic view. It identifies each pixel by assigning a unique class ID, and an instance ID. Specifically, it can classify 'thing' from 'stuff', and provide pixel-wise results of semantic prediction and object detection. As a result, it can solve both semantic segmentation and instance segmentation tasks through a unified single model, producing two different contexts for two segmentation tasks. Semantic segmentation task focuses on how to obtain multi-scale features from large receptive field, without losing low-level features. On the other hand, instance segmentation task focuses on how to separate 'thing' from 'stuff' and how to produce the representation of detected objects. With the advances of both segmentation techniques, several panoptic segmentation models have been proposed. Many researchers try to solve discrepancy problems between results of two segmentation branches that can be caused on the boundary of the object. In this survey paper, we will introduce the concept of panoptic segmentation, categorize the existing method into two representative methods and explain how it is operated on two methods: top-down method and bottom-up method. Then, we will analyze the performance of various methods with experimental results.

• 대한임베디드공학회논문지
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• 제11권6호
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• pp.361-367
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• 2016

In this paper, we propose an improved single view metrology (SVM) algorithm to accurately measure the height of objects. In order to accurately measure the size of objects, vanishing points have to be correctly estimated. There are two methods to estimate vanishing points. First, the user has to choose some horizontal and vertical lines in real world. Then, the user finds the cross points of the lines. Second, the user can obtain the vanishing points by using software algorithm such as [6-9]. In the former method, the user has to choose the lines manually to obtain accurate vanishing points. On the other hand, the latter method uses software algorithm to automatically obtain vanishing points. In this paper, we apply image resizing and edge sharpening as a pre-processing to the algorithm in order to improve performance. The estimated vanishing points algorithm create four vanishing point candidates: two points are horizontal candidates and the other two points are vertical candidates. However, a common image has two horizontal vanishing points and one vertical vanishing point. Thus, we eliminate a vertical vanishing point candidate by analyzing the histogram of angle distribution of vanishing point candidates. Experimental results show that the proposed algorithm outperforms conventional methods, [6] and [7]. In addition, the algorithm obtains similar performance with manual method with less than 5% of the measurement error.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.782-788
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• 2008

In this paper, a comparison about two representative Transfer Path Analysis(TPA) methods for air-borne noise based on, matrix inversion method and pressure transmissibility, are presented on the view point of crosstalk effect between sources. In order to assess accuracy of two methods according to path models between virtual airborne noise sources, experiments are made for two cases, weak and strong crosstalk effect condition, by using acrylic vehicle model. Based on this assessment, the paper presents a reasonable application criteria for TPA method according to the circumstances of air-borne noise sources.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.566-571
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• 2009

A calibration method for multiple sets of stereo vision cameras is proposed. To measure the three-dimensional shape of a very long object, measuring the object at different viewpoints and registration of the data are necessary. In this study, two lasers beams generate two strings of calibration targets, which form straight lines in the world coordinate system. An evaluation function is defined to calculate the sum of the squares of the distances between each transformed target and the fitted line representing the laser beam to each target, and the distances between points appearing in the data sets of two adjacent viewpoints. The calculation process for the approximation method based on data linearity is presented. The experimental results show the effectiveness of the method.

• Journal of International Society for Simulation Surgery
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• 제1권2호
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• pp.57-61
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• 2014

We present a robust 3D facial reconstruction method using a single image generated by face-specific super resolution technique. Based on the several consecutive frames with low resolution, we generate a single high resolution image and a three dimensional facial model based on it. To do this, we apply PME method to compute patch similarities for SR after two-phase warping according to facial attributes. Based on the SRI, we extract facial features automatically and reconstruct 3D facial model with basis which selected adaptively according to facial statistical data less than a few seconds. Thereby, we can provide the facial image of various points of view which cannot be given by a single point of view of a camera.

• 대한기계학회논문집A
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• 제24권1호
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• pp.240-249
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• 2000

An improved global optimization algorithm is developed by extending the domain elimination method. The concept of triangular patch consists of two or more trajectories of local minimizations is introduced to widen the attraction region of the domain elimination method. Using the an-]c between each of three vertices of the patch and a design point, we measure the proximity, between the design point and the patch. With the Gram-Schimidt orthonormalization, this method can be extended to general n-dimensional problems. We code the original domain elimination algorithm and a patch-based algorithm. Then we compare the performance of two algorithms. Through the well-known example problems. the algorithm using patch is shown to be superior to the original domain elimination algorithm in view of computational efficiency.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.201-211
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• 2010

본 연구의 목적은 정보 디자인 유형 중에서 상대적으로 "노출 시간이 짧지만 정보 전달력이 강한 정보" 즉, STM 정보(Short-term Memorable Information)” 에 대한 사용자의 인지력을 높이기 위한 방법을 모색하는 것이다. 연구를 통해 STM 정보의 디자인 속성을 고찰하고 거시적 관점에서 디자인적 표현 방법을 다음과 같이 제안하였다. STM 정보는 기능변수의 조작, 방법, 사건, 사용 예라는 네 가지 시각화 속성을 기준으로 시각적 재현 측면에서 '이해도(Understandable)', '접근성(Accessibility)' 속성이 충족되어야 한다. 또한 사용자 조작 측면에서는 '무오류(Errorless)', '적정성(Timeliness)' 속성이 충족되어야 한다. 각 측면에서의 거시적 표현 방법으로써, 시각적 재현 측면에서 "속성이론", "인식모형", "정보 주도성(Proactivity)의 최대화", "잉여 정보의 최소화", "이중부호의 사용"을 제안했으며, 사용자 조작측면에서 "맥락효과", 일차적 독특성을 중심으로 한 "기억부호화", "정보 주사(Scanning)"의 두 가지 방법을 제안했다. 사용자 설문 인터뷰를 통해서 앞서 제안한 8가지 표현 방법의 효율성에 관한 확증 및 STM 정보에 대한 사용자 인지패턴을 발견하였다. 본 연구에서의 주요 발견점을 토대로 향후에는 노출시간별 효과적인 정보 표현 및 그에 따른 응용 방법에 관한 연구가 진행될 필요가 있다.

• 전자공학회논문지
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• 제50권12호
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• pp.159-167
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• 2013

스트레오뷰(Stereoview) 시스템에서 카메라 위치 또는 광원의 변화는 양안에 해당하는 두 영상 사이에서 휘도에 대한 색상 분포에 차가 발생 한다. 이러한 색상변화 차는 입체영상(3D) 코딩의 품질을 저하 시키거나 적합하지 않는 프레임이 발생한다. 이러한 휘도에 대한 색상분포 차를 보정하기 위하여 본 논문에서는 스트레오뷰 코딩을 위한 효율적인 히스토그램 구간 보정방법을 제안하였다. 제안한 방법은 타겟뷰의 히스토그램을 분석하여 두 개의 영역으로 구분한 후 기준이 되는 영상의 히스토그램과 영역별 최대 매칭 영역을 분석하여 컬러편차를 보정하도록 하였다. 그리고 제안한 히스토그램 매칭 방법을 다른 컬러 보정방법과 비교하여 휘도 성분 교정을 검증 하였다. 실험 결과 제안하는 알고리즘이 연산 속도와 휘도 교정 PSNR(Peak Signal to Noise Ratio) 결과에서 더 좋은 결과를 보였다.