• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.546-550
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• 2002

This paper proposes an error compensation method that improves accuracy with geometry information of injection molding parts. Geometric information can give an improved accuracy in reverse engineering. Measuring data can not lead to get accurate geometric model, including errors of physical parts and measuring machines. Measuring data include errors which can be classified into two types. One is molding error in product, the other is measuring error. Measuring error includes optical error of laser scanner, deformation by probe forces of CMM and machine error. It is important to compensate these in reverse engineering. Least square method(LSM) provides the cloud data with a geometry compensation, improving accuracy of geometry. Also, the functional shape of a part and design concept can be reconstructed by error compensation using geometry information.

• 한국멀티미디어학회논문지
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• 제13권12호
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• pp.1748-1759
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• 2010

We extend the octree subdivision process from Cartesian coordinates to spherical coordinates to develop more efficient space-partitioning structure for surface models. As an application of the proposed structure, we apply the octree subdivision in spherical coordinates ("S-Octree") to geometry compression in progressive mesh coding. Most previous researches on geometry-driven progressive mesh compression are devoted to improve predictability of geometry information. Unlike this, we focus on the efficient information storage for the space-partitioning structure. By eliminating void space at initial stage and aligning the R axis for the important components in geometry information, the S-Octree improves the efficiency in geometry information coding. Several meshes are tested in the progressive mesh coding based on the S-Octree and the results for performance parameters are presented.

• 한국정보처리학회논문지
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• 제7권1호
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• pp.252-265
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• 2000

본 논문에서는 3차원 그래픽의 처리 과정 중 부동 소수점 연산이 많은 소요되는 geometry 프로세싱 처리 방법과 계산량을 단계별로 분석하였다. 그리고, 그래픽 프로세싱의 수행 특성을 추출하여, 이에 맞는 기능 유닛을 설계하고, 데이터 처리 방안과 제안하는 geometry 프로세서의 구조를 설명한 다음, 성능을 분석하였다. 제안하는 geometry 프로세서는 부동 소수점 덧셈, 곱셈, 나눗셈 연산을 동시에 수행 가능하며, geometry 프로세싱 전 단계를 수행하는데 23.5%의 성능 향상이 있었다. 그리고, 나눗셈/제곱근 연산을 위해서 면적대 성능비가 우수한 SRT 나눗셈 연산기를 추가하여 곱셈 연산기를 이용하는 연산기보다 약 23%의 성능 향상을 이루었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권6호
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• pp.2132-2143
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• 2015

This paper presents two distance geometry-based algorithms for wireless location in cellular network systems-distance geometry filtering (DGF) and distance geometry constraint (DGC). With time-of-arrival range measurements, the DGF algorithm estimates the mobile station position by selecting a set of measurements with relatively small NLOS (non-line-of-sight) errors, and the DGC algorithm optimizes the measurements first and then estimates the position using those optimized measurements. Simulation results show that the proposed algorithms can mitigate the impact of NLOS errors and effectively improve the accuracy of wireless location.

• 대한전자공학회논문지SD
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• 제43권2호
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• pp.24-33
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• 2006

본 논문에서는 휴대용 정보기기 시스템에서 더욱 향상된 실시간 3D 그래픽 가속 능력을 갖는 SoC 구현을 위해 효과적인 3D 그래픽 Geometry 처리 IP 구조를 연구하였다. 이를 기반으로 3D 그래픽 Geometry 처리 과정에 필요한 부동소수점 연산기를 설계하였으며, 내장형 3D 그래픽 국제 표준인 OpenGL-ES를 지원하는 부동소수점 Geometry 프로세서를 설계하였다. 설계된 Geometry 프로세서는 Xilinx-Vertex2 FPGA에서 160k gate의 면적으로 구현되었으며, 80 MHz의 동작주파수 환경에서 실제 3D 그래픽 데이터를 이용하여 Geometry 처리 과정의 성능 측정 실험을 하였다. 실험 결과 80 MHz의 동작주파수에서 초당 1.5M 개의 폴리곤 처리 성능이 확인되었으며, 이는 타 3D 그래픽 가속 프로세서에 비하여 평균 2배 이상의 Geometry 처리 성능이다. 본 지오메트리 프로세서는 Hynix 0.25um CMOS 공정에 의한 측정결과 83.6mW의 소모전력을 나타낸다.

• 한국정밀공학회지
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• 제19권10호
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• pp.99-106
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• 2002

This paper proposes an error compensation method that improves accuracy with geometry information of injection molding parts. Geometric information can give an improved accuracy in reverse engineering. Measuring data can not lead to get accurate geometric model, including errors of physical parts and measuring machines. Measuring data include errors which can be classified into two types. One is molding error in product, the other is measuring error. Measuring error includes optical error of laser scanner, deformation by probe forces of CMM and machine error. It is important to compensate these in reverse engineering. Least square method (LSM) provides the cloud data with a geometry compensation, improving accuracy of geometry. Also, the functional shape of a part and design concept can be reconstructed by error compensation using geometry information.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.81-87
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• 2018

In this paper, in order to maximize the input process efficiency of the building energy simulation field, the authors developed the automatic extraction module of spatial information based BIM geometry information. Existing research or software extracts geometry information based on object information, but it can not be used in the field of energy simulation because it is inconsistent with the geometry information of the object constituting the thermal zone of the actual building model. Especially, IFC-based geometry information extraction module is needed to link with other architectural fields from the viewpoint of reuse of building information. The study method is as follows. (1) Grasp the category and attribute information to be extracted for energy simulation and Analyze the IFC structure based on spatial information (2) Design the algorithm for extracting and reprocessing information for energy simulation from IFC file (use programming language Phython) (3) Develop the module that generates a geometry information database based on spatial information using reprocessed information (4) Verify the accuracy of the development module. In this paper, the reprocessed information can be directly used for energy simulation and it can be widely used regardless of the kind of energy simulation software because it is provided in database format. Therefore, it is expected that the energy simulation process efficiency in actual practice can be maximized.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.57-60
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• 2002

Facial features are often used for human computer interface(HCI). This paper proposes a method to detect facial features using color and facial geometry information. Face region is first extracted by using color information, and then the pupils are detected by applying a separability filter and facial geometry constraints. Mouth is also extracted from Cr(coded red) component. Experimental results shows that the proposed detection method is robust to a wide range of facial variation in position, scale, color and gaze.

• 복식
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• 제62권7호
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• pp.67-78
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• 2012

This study considered and analyzed the influence of changed clothing silhouettes on the textile patterns by investigating the changes of geometry patterns in response to the changes of western women's apparel silhouette in the 1960s. The period scope of research was limited to the 1960s, and the research object was set as the geometry patterns seen in the designer's high-fashion. The researcher investigated the clothing silhouette and the textile patterns in 1960s by reviewing the literature about domestic and foreign books, research papers, domestic and foreign fashion magazines, information on the Internet. For the western women's apparel in 1960s, some active, simple styles were popular under the social atmosphere when more women actively entered the society. Influenced by popular art trends at that time, the silhouette was expressed in the geometry pattern among many textile patterns. The geometry pattern either appeared as a regularly overall repeating geometry pattern and the regularly partial repeating geometry pattern. The regularly overall repeating geometry pattern arranged the straight lines in the same interval. But the regularly partial repeating geometry pattern was arranged without order to emphasize the motif in some parts of clothing or to give some ornament effect, or was arranged asymmetrically.

• 한국수학교육학회지시리즈A:수학교육
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• 제44권2호
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• pp.297-306
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• 2005

In this paper, we propose a computer environment class for student's mental representations about non-Euclidean geometry. Through the software Cinderella, students construct knowledge about non-Euclidean geometry and recognize differentness between Euclidean and non-Euclidean geometry. Also they recognize an existence of non-Euclidean geometry newly and its mental representations with images represented in Cinderella. In geometry class, we make students can use many representations systematically and can figure a visual internal image by emphasizing a transform process. And then students can reason about non-Euclidean geometry.