• 한국CDE학회논문집
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• 제9권4호
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• pp.373-381
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• 2004

Using standard components of a press die is recognized as a way for a cost reduction and a short lead time. It also provides a way for a quick maintenance of a die under repair. It is expected to contribute to integration of CAD/CAM system for manufacturing dies in the future. This paper presents a 3D CAD library which is constructed using the standard components and is used for designing a press die. This 3D CAD library is generated by a database system made of Microsoft Access for standard components and by CATIA V5 R10 API for geometric features. The library is implemented using Visual Basic 6.0 utility of CATIA API function in the Windows NT environment. It creates a 3D model of the standard components of press die easily when a die designer inputs numerical values of geometric features and the BOM of the completely assembled parts. It also generates automatically the assembly drawing of die set by using variables for standard values of die parts. Therefore users can save the cost of time to design the press die components, and even a beginner can use this program with ease. The test results of the 3D CAD library for designing shearing and bending dies verify its usefulness and feasibility.

• 한국멀티미디어학회논문지
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• 제6권7호
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• pp.1139-1148
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• 2003

개인의 identity가 더욱더 중요시되는 현시대에서 ID 도용이나 분실로 인한 피해를 막거나 줄이기 위한 최적의 해법으로 생체 인식이 연구되고 있다. 얼굴인식에 의한 생체인식은 특정 시스템의 입력부위에 신체 일부에 대한 접촉을 강요하지 않으므로 최근 많이 각광받고 있는 분야이다. 그러나 입력된 얼굴 영상은 카메라의 포착 거리에 따라 크기가 달라질 수 있고 또한 얼굴의 기울기 등에 의해 같은 영상이라 할지라도 다른 특징 값을 줄 수밖에 없는 문제점을 안고 있다. 본 논문에서는 주어진 입력영상에 대한 이동, 축소, 확대, 그리고 회전의 단순한 기하학적인 처리를 함으로써 정면 얼굴 영상에 대해 정해진 임계값을 초과 하지 않는 범위에서 일정한 특징 값을 얻을 수 있었다. 본 논문에서 구축된 시스템으로 40 세트의 400 영상에 대한 인식 율을 테스트한 결과 92 %의 높은 인식 율을 보였다.

• 한국멀티미디어학회논문지
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• 제6권4호
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• pp.698-706
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• 2003

The primary goal of surface approximation is to reduce the degree of deviation of the simplified surface from the original surface. However it is difficult to define the metric that can measure the amount of deviation quantitatively. Many of the existing studies analogize it by using the change of the scalar quantity before and after simplification. This approach makes a lot of sense in the point that the local surfaces with small scalar are relatively less important since they make a low impact on the adjacent areas and thus can be removed from the current surface. However using scalar value alone there can exist many cases that cannot compute the degree of geometric importance of local surface. Especially the perceptual geometric features providing important clues to understand an object, in our observation, are generally constructed with small scalar value. This means that the distinguishing features can be removed in the earlier stage of the simplification process. In this paper, to resolve this problem, we present various factors and their combination as the metric for calculating the deviation error by introducing the orientation of local surfaces. Experimental results indicate that the surface orientation has an important influence on measuring deviation error and the proposed combined error metric works well retaining the relatively high curvature regions on the object's surface constructed with various and complex curvatures.

• 한국BIM학회 논문집
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• 제7권1호
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• pp.18-27
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• 2017

Although Industry Foundation Classes (IFC) provide standards for exchanging Building Information Modeling (BIM) data, authoring tools still require manual mapping between BIM entities and IFC classes. This leads to errors and omissions, which results in corrupted data exchanges that are unreliable and thus compromise the validity of IFC. This research explored precedent work by Krijnen and Tamke, who suggested ways to automate the mapping of IFC classes using a machine learning technique, namely anomaly detection. The technique incorporates geometric features of individual components to find outliers among entities in identical IFC classes. This research primarily focused on applying this approach on two architectural BIM models and determining its feasibility as well as limitations. Results indicated that the approach, while effective, misclassified outliers when an IFC class had several dissimilar entities. Another issue was the lack of entities for some specific IFC classes that prohibited the anomaly detection from comparing differences. Future research to improve these issues include the addition of geometric features, using novelty detection and the inclusion of a probabilistic graph model, to improve classification accuracy.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.38-46
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• 2013

The change in radically changing era requires various interpretation of interior space and application according to it Minimalism shows simple and pure geometric structure and has been influencing to every aspect encompassing space till present. The features of minimalism in space is geometric structure and composition of simple and repetitive line, restrained simple space, pure and structural simplicity. When minimalism construction is discussed, the vocabulary of simplicity has been followed incidentally and has been discussed as concept of simplicity in new viewpoint through historical flow. The purpose of this study is analyzing basic features of John Pawson's ways of working and trying to define the semantics of the new simplicity concept in modern interior space. The new simplicity in John Pawson shows interactive relationship of eastern and western through basic consideration of fundamental elements such as space, light and materials. The relational simple in intermediation of the new simplicity expressed by amalgamation of eastern and western further from disparate interpretation for simplicity expressed in eastern and western is to review back the basic meaning of simplicity in minimalism. And I hope this study can offer various directions for new interior space accepting theory of the new simplicity and I think that new constructional alternative is required as physical space which can be matched with era of social, environmental chaos caused by this theory of the new simplicity.

• 전자공학회논문지CI
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• 제45권5호
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• pp.56-62
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• 2008

의사결정나무를 구성하여 강판튜브 비파괴평가에 사용하는 산업용 CR영상의 측정 패턴인식을 도모한다. 본래 비파괴평가는 기계학습기법에 의한 패턴식별과 그 분류에 적합한 분야이다. 의사결정나무의 속성들은 비파괴평가 테스트 절차로부터 취한다. 방사선조사 입사각, 경사도 및 거리 둥의 기하학적 특성들은 입력 영상 데이터 분석으로부터 추정한다. 이 요소들은 대상 입력을 의사결정나무에서 미리 정해진 분류에로 정확히 그리고 쉽게 분류가 이루어지도록 한다. 이 알고리즘은 비파괴평가 결과의 특성화를 간단히 하며 특성 결정을 간편하게 한다. 실험 결과는 제안한 알고리즘의 유용성을 보였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.147-152
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• 2003

Aerial Images are usually used to extract 3-D coordinates of various urban features. In this process, the stereo matching of images should be performed precisely to extract these information from aerial Images. In this research, we proposed a matching technique based on geometric features of lanes. We extracted lanes from aerial images and grouped into 4 lane's types. They are lane lines, dotted lines, arrow lane, safety zone. After preprocessing, We will match them by spatial relationships, for example, the distance and orientation between the extracted features. In the future, we will obtain lane coordinates and reconstruct 3-d coordinates of roads.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.138-145
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• 2016

LLAH(Locally Likely Arrangement Hashing) is a method which describes image features by exploiting the geometric relationship between their neighbors. Inherently, it is more robust to large view change and poor scene texture than conventional texture-based feature description methods. However, LLAH strongly requires that image features should be detected with high repeatability. The problem is that such requirement is difficult to satisfy in real applications. To alleviate the problem, this paper proposes a method that improves the matching rate of LLAH by exploiting together the brightness of features. Then, it is verified that the matching rate is increased by about 5% in experiments with synthetic images in the presence of Gaussian noise.

• 한국멀티미디어학회논문지
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• 제13권6호
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• pp.875-883
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• 2010

In this paper, we present a secure biometric hashing scheme for face recognition by random fusion of global and local features. The Fourier-Mellin transform and Radon transform are adopted respectively to form specialized representation of global and local features, due to their invariance to geometric operations. The final biometric hash is securely generated by random weighting sum of both feature sets. A fourfold key is involved in our algorithm to ensure the security and privacy of biometric templates. The proposed biometric hash can be revocable and replaced by using a new key. Moreover, the attacker cannot obtain any information about the original biometric template without knowing the secret key. The experimental results confirm that our scheme has a satisfactory accuracy performance in terms of EER.

• Journal of information and communication convergence engineering
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• 제9권2호
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• pp.207-211
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• 2011

This paper presents a method for facial feature representation and recognition from the Covariance Matrices of the Gabor-filtered images. Gabor filters are a very powerful tool for processing images that respond to different local orientations and wave numbers around points of interest, especially on the local features on the face. This is a very unique attribute needed to extract special features around the facial components like eyebrows, eyes, mouth and nose. The Covariance matrices computed on Gabor filtered faces are adopted as the feature representation for face recognition. Geodesic distance measure is used as a matching measure and is preferred for its global consistency over other methods. Geodesic measure takes into consideration the position of the data points in addition to the geometric structure of given face images. The proposed method is invariant and robust under rotation, pose, or boundary distortion. Tests run on random images and also on publicly available JAFFE and FRAV3D face recognition databases provide impressively high percentage of recognition.