• Journal of International Society for Simulation Surgery
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• 제2권1호
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• pp.7-9
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• 2015

Purpose In the many face-related application such as head pose estimation, 3D face modeling, facial appearance manipulation, the robust and fast facial feature extraction is necessary. We present the facial feature extraction method based on shape regression and feature selection for real-time facial feature extraction. Materials and Methods The facial features are initialized by statistical shape model and then the shape of facial features are deformed iteratively according to the texture pattern which is selected on the feature pool. Results We obtain fast and robust facial feature extraction result with error less than 4% and processing time less than 12 ms. The alignment error is measured by average of ratio of pixel difference to inter-ocular distance. Conclusion The accuracy and processing time of the method is enough to apply facial feature based application and can be used on the face beautification or 3D face modeling.

• 한국통신학회논문지
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• 제35권12C호
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• pp.995-1003
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• 2010

영상, 동영상 및 3D 모델의 인증 및 복사방지를 위한 콘텐츠 기반 해쉬 함수는 강인성 및 보안성의 성질을 만족하여야 한다. 이들 중 해쉬의 보안성을 분석하기 위한 방법으로 미분 엔트로피 방법이 제시되었으나, 이는 영상 해쉬 추출에서만 적용되었다. 따라서 본 논문에서는 미분 엔트로피 기반의 3D 모델 해쉬 특징 추출의 보안성을 분석하기 위한 모델링을 제안한다. 제안한 보안성 분석 모델링에서는 3D 모델 해싱 기법 중 가장 일반적인 두 가지 형태의 특정 추출 방법을 제시한 다음, 이들 방법들을 미분 엔트로피 기반으로 보안성을 분석하였다. 과로부터 해쉬 추출 방법에 대한 보안성을 분석하고 보안성과 강인성과의 상호보완관계에 대하여 논하였다.

• 인터넷정보학회논문지
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• 제8권6호
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• pp.135-144
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• 2007

특성 모델(Feature Model)은 소프트웨어 제품 라인 개발 시 도메인 공학 단계에서 제품들 사이의 공통된 개념들과 서로 다른 개념들을 모델링하는데 널리 사용된다. 특성 모델로부터 특정 제품에 포함될 특성들을 선택한 결과를 특성 구성(Feature Configuration)이라고 하며, 이것은 특정 제품에 대한 요구 사항을 나타낸다. 현재 소프트웨어 제품 라인 개발 시 특성 모델과 특성 구성을 어떻게 구축하고 이용하는지에 대한 연구는 많이 되어 있지만, 이들에 대한 정형적 시맨틱과 논리적 추론에 대한 연구는 부족하다. 본 논문에서는 소프트웨어 제품 라인 공학에서의 표준 문제로 제안된 Graph Product Line을 예제로 하여 규칙 기반 시스템인 JESS를 이용한 특성 구성 검증 기법을 제안한다. 본 논문의 기법은 특성 구성의 불일치성을 일으키는 원인을 명확히 제시하는 장점을 가지며, 자바 언어와의 결합성이 뛰어난 JESS 시스템에 기반을 두었기 때문에 다른 소프트웨어 제품 라인 개발 환경과 쉽게 통합될 수 있다.

• 대한기계학회논문집
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• 제17권10호
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• pp.2446-2456
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• 1993

By virtue of progress of computer science, CAD/CAM technology has been developed greatly in each area. But the problems in the integration of CAD/CAM are not yet solved completely. The reason is that the exchange of data between CAD and CAM is difficult because the domains of design and manufacturing are different in nature. To solve this problem, a feature based modeller is developed in this study, which makes it possible to communicate between design and manufacturing through features. The modeller has feature, the concept of semi-bounded plane is introduced, and implemented as a B-rep sheet model using half-edge data structure. The features are then created on a part by local modification of the boundary on a part based on feature template information. This approach generalizes the modelling of features in a geometry model.

• 대한음성학회지:말소리
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• 제67호
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• pp.167-180
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• 2008

This paper describes a novel spectral envelope conversion method based on Gaussian mixture model (GMM). The core of this paper is rearranging source feature vectors in input space to the transformed feature vectors in feature space for the better modeling of GMM of source and target features. The quality of statistical modeling is dependent on the distribution and the dimension of data. The proposed method transforms both of the distribution and dimension of data and gives us the chance to model the same data with different configuration. Because the converted feature vectors should be on the input space, only source feature vectors are rearranged in the feature space and target feature vectors remain unchanged for the joint pdf of source and target features using KPCA. The experimental result shows that the proposed method outperforms the conventional GMM-based conversion method in various training environment.

• 한국공작기계학회논문집
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• 제13권3호
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• pp.30-36
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• 2004

The exchange of model design data among heterogeneous CAD systems is very difficult because each CAD system has different data structures suitable for its own functions. STEP represents product information in a common computer-interpretable form that is required to remain complete and consistent when the product information is needed to be exchanged among different computer systems. However, STEP has complex architecture to represent point, line, curve and vectors of element. Moreover it can't represent geometry data of feature based models. In this study, a structure of XML document that represents geometry data of feature based models as neutral format has been developed. To use the developed XML document, a converter also has been developed to exchange modules so that it can exchange feature based data models among heterogeneous CAD systems. Developed XML document and Converter have been applied to commercial CAD systems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.434-440
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• 2003

The exchange of model design date among heterogeneous CAD systems is a difficult task because each system has different data structures suitable for its own functions. STEP has been able to represent product information as a common computer-interpretable form that is required to remain complete and consistent when the product informant is needed to be exchanged among different computer system. However, STEP has difficult architecture in is representing point, line, curve and vectors of element, more over it can't represent geometry data of feature based models. In this study, a structure of XML document that represents geometry data of feature based models as neutral format has been developed. To use the developed XML document, a Converter has also been developed to exchange modules so that it can exchange feature based data models among heterogeneous CAD systems. Aa for evaluation of the developed XML document and Converter, Solidworks and SolidEdge are selected.

• 한국CDE학회논문집
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• 제10권6호
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• pp.432-443
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• 2005

Recent three-dimensional feature-based CAD systems based on solid or non-manifold modelling functionality have been widely used for product design in manufacturing companies. When product models associated with features are used in various downstream applications such as analysis, however, simplified and abstracted models at various levels of detail (LODs) are frequently more desirable and useful than the full detailed model. To provide multi-resolution models, the features need to be rearranged according to a criterion that measures the significance of the feature. However, if the features are rearranged, the resulting shape is possibly different from the original because union and subtraction Boolean operations are not commutative. To solve this problem, in this paper, the new concept of the effective zone of a feature is defined and identified using Boolean algebra. By introducing the effective zone, an arbitrary rearrangement of features becomes possible and arbitrary LOD criteria may be selected to suit various applications. Besides, because the effective zone of a feature is independent of the data structure of the model, the multi-resolution modelling algorithm based on the effective zone can be implemented on any 3D CAD system based on conventional solid representations as well as non-manifold topological (NMT) representations.

• 정보보호학회논문지
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• 제33권6호
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• pp.881-891
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• 2023

최근에는 인공지능을 활용하여 악성 URL을 탐지하는 다양한 연구가 진행되고 있으며, 대부분의 연구 결과에서 높은 탐지 성능을 보였다. 그러나 고전 머신러닝을 활용하는 경우 feature를 분석하고 선별해야 하는 추가 비용이 발생하며, 데이터 분석가의 역량에 따라 탐지 성능이 결정되는 이슈가 있다. 본 논문에서는 이러한 이슈를 해결하기 위해 URL lexical feature를 자동으로 추출하는 딥러닝 모델의 일부가 고전 머신러닝 모델에 결합된 형태인 DL-ML Fusion Hybrid 모델을 제안한다. 제안한 모델로 직접 수집한 총 6만 개의 악성과 정상 URL을 학습한 결과 탐지 성능이 최대 23.98%p 향상되었을 뿐만 아니라, 자동화된 feature engineering을 통해 효율적인 기계학습이 가능하였다.

• 한국CDE학회논문집
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• 제10권4호
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• pp.262-273
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• 2005

For CAD data users, few things are as frustrating as receiving CAD data that is unusable due to poor data quality. Users waste time trying to get better data, fixing the data, or even rebuilding the data from scratch from paper drawings or other sources. Most related works and commercial tools handle the boundary representation (B-Rep) shape of CAD models. However, we propose a design history?based approach for healing CAD model errors. Because the design history, which covers the features, the history tree, the parameterization data and constraints, reflects the design intent, CAD model errors can be healed by an interdependency analysis of the feature commands or of the parametric data of each feature command, and by the reconstruction of these feature commands through the rule-based reasoning of an expert system. Unlike other B Rep correction methods, our method automatically heals parametric feature models without translating them to a B-Rep shape, and it also preserves engineering information.