• Title/Summary/Keyword: Geometric Modeling

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Graphemes Segmentation for Arabic Online Handwriting Modeling

  • Boubaker, Houcine;Tagougui, Najiba;El Abed, Haikal;Kherallah, Monji;Alimi, Adel M.
    • Journal of Information Processing Systems
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    • v.10 no.4
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    • pp.503-522
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    • 2014
  • In the cursive handwriting recognition process, script trajectory segmentation and modeling represent an important task for large or open lexicon context that becomes more complicated in multi-writer applications. In this paper, we will present a developed system of Arabic online handwriting modeling based on graphemes segmentation and the extraction of its geometric features. The main contribution consists of adapting the Fourier descriptors to model the open trajectory of the segmented graphemes. To segment the trajectory of the handwriting, the system proceeds by first detecting its baseline by checking combined geometric and logic conditions. Then, the detected baseline is used as a topologic reference for the extraction of particular points that delimit the graphemes' trajectories. Each segmented grapheme is then represented by a set of relevant geometric features that include the vector of the Fourier descriptors for trajectory shape modeling, normalized metric parameters that model the grapheme dimensions, its position in respect to the baseline, and codes for the description of its associated diacritics.

3D geometric model generation based on a stereo vision system using random pattern projection (랜덤 패턴 투영을 이용한 스테레오 비전 시스템 기반 3차원 기하모델 생성)

  • Na, Sang-Wook;Son, Jeong-Soo;Park, Hyung-Jun
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2005.05a
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    • pp.848-853
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    • 2005
  • 3D geometric modeling of an object of interest has been intensively investigated in many fields including CAD/CAM and computer graphics. Traditionally, CAD and geometric modeling tools are widely used to create geometric models that have nearly the same shape of 3D real objects or satisfy designers intent. Recently, with the help of the reverse engineering (RE) technology, we can easily acquire 3D point data from the objects and create 3D geometric models that perfectly fit the scanned data more easily and fast. In this paper, we present 3D geometric model generation based on a stereo vision system (SVS) using random pattern projection. A triangular mesh is considered as the resulting geometric model. In order to obtain reasonable results with the SVS-based geometric model generation, we deal with many steps including camera calibration, stereo matching, scanning from multiple views, noise handling, registration, and triangular mesh generation. To acquire reliable stere matching, we project random patterns onto the object. With experiments using various random patterns, we propose several tips helpful for the quality of the results. Some examples are given to show their usefulness.

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Evaluation of Geometric Modeling for KOMPSAT-1 EOC Imagery Using Ephemeris Data

  • Sohn, Hong-Gyoo;Yoo, Hwan-Hee;Kim, Seong-Sam
    • ETRI Journal
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    • v.26 no.3
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    • pp.218-228
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    • 2004
  • Using stereo images with ephemeris data from the Korea Multi-Purpose Satellite-1 electro-optical camera (KOMPSAT-1 EOC), we performed geometric modeling for three-dimensional (3-D) positioning and evaluated its accuracy. In the geometric modeling procedures, we used ephemeris data included in the image header file to calculate the orbital parameters, sensor attitudes, and satellite position. An inconsistency between the time information of the ephemeris data and that of the center of the image frame was found, which caused a significant offset in satellite position. This time inconsistency was successfully adjusted. We modeled the actual satellite positions of the left and right images using only two ground control points and then achieved 3-D positioning using the KOMPSAT-1 EOC stereo images. The results show that the positioning accuracy was about 12-17 m root mean square error (RMSE) when 6.6 m resolution EOC stereo images were used along with the ephemeris data and only two ground control points (GCPs). If more accurate ephemeris data are provided in the near future, then a more accurate 3-D positioning will also be realized using only the EOC stereo images with ephemeris data and without the need for any GCPs.

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Effect of Slab-base Friction on Response of JCP Slab with Different Material and Geometric Properties

  • Sun, Ren-Juan;Lim, Jin-Sun;Jeong, Jin-Hoon
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.5
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    • pp.99-110
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    • 2007
  • A single slab concrete pavement has been modeled and analyzed by ABAQUS program. The stress and displacement of the JCP slab under traffic load with frictionless contact interaction between slab and base calculated by ABAQUS program have been compared with the results obtained by KENSLABS program. The results of the stresses of the two modeling show similar tendency and the difference of the two modeling is very small however the results of the displacement of the two modeling show some dissimilarity. In order to analyze the effects of material and geometric properties on the responses of slab, some varying parameters were chosen as input for the modeling. The changing parameters include the thickness and elastic modulus of the concrete slab, the thickness and elastic modulus of base and the elastic modulus of the subgrade. The contact interaction between the slab and base layer had been also studied and different friction coefficient 0, 2.5, 6.6, 7.5, 8.9 had been used to simulate the different friction interface condition. The results of the analysis showed that the responses of the concrete slab vary with the material and geometric properties of the pavement structure and the slab-base friction condition.

Pipe Atuo-Routing with Design Knowledge-base (선박용 배관의 Auto-Routing을 위한 설계 전문가 시스템)

  • 강상섭;명세현;한순흥
    • Korean Journal of Computational Design and Engineering
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    • v.2 no.1
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    • pp.1-10
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    • 1997
  • Finding the optimum route of ship's pipes is complicated and time-consuming process. Experience of designers is the main tool in this process. To reduce design man-hours and human errors a design expert system shell and a geometric modeler is used to automate the design process. In this paper, a framework of the intelligent CAD system for pipe auto-routing is suggested, which consists of general-purpose expert system shell and a geometric modeler. The design expert system and the geometric modeling kernel have been integrated. The CADDS5 of Computervision is used as the overall CAD environment. The Nexpert Object of Neuron Data is used as the expert system shell. The CADDS5 ISSM is used as the interface that creates and modifies geometric models of pipes. Existing algorithms for the routing problem have been analyzed. Most of them are to solve the 2-D circuit routing problems. Ship piping system, specially within the engine room, is a complicated, large scale 3-D routing problem. Methods of expert system have been used to find the route of ship pipes on the main deck.

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A Study on the 3-D Geometric Modeler for Safety Assessment of Damaged Ships (손상선박의 안전성평가를 위한 3차원 형상 모델러에 관한 연구)

  • 이동곤;이순섭;박범진
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.6
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    • pp.30-36
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    • 2003
  • To improve survivability of damaged ship, assessment of stability and structural safety, and behavior analysis in wave is required. Prediction of sinking time, damage stability and structural strength considering progressive flooding and dynamic force in wave is very important. To do it, a geometric model which can be express damaged ship is prepared. This paper described the geometric modeler for survivability assessment of damaged ship. The modeler is developed based on 3-D geometric modeling kernel, ACIS. The hull form and compartment definition is available fundamentally. And requirement for modeler contains data generation and interface for hydrostatic calculation, behavior analysis, and longitudinal strength analysis and so on. To easy access modeling system by conventional user such as crew, user interface is developing.

Finite element modeling of a deteriorated R.C. slab bridge: lessons learned and recommendations

  • Ho, I-Kang;Shahrooz, Bahram M.
    • Structural Engineering and Mechanics
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    • v.6 no.3
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    • pp.259-274
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    • 1998
  • The test results from non-destructive and destructive field testing of a three-span deteriorated reinforced concrete slab bridge are used as a vehicle to examine the reliability of available tools for finite-element analysis of in-situ structures. Issues related to geometric modeling of members and connections, material models, and failure criteria are discussed. The results indicate that current material models and failure criteria are adequate, although lack of inelastic out-of-plane shear response in most nonlinear shell elements is a major shortcoming that needs to be resolved. With proper geometric modeling, it is possible to adequately correlate the measured global, regional, and local responses at all limit states. However, modeling of less understood mechanisms, such as slab-abutment connections, may need to be finalized through a system identification technique. In absence of the experimental data necessary for this purpose, upper and lower bounds of only global responses can be computed reliably. The studies reaffirm that success of finite-element models has to be assessed collectively with reference to all responses and not just a few global measurements.

Evaporation Process Modeling for Large OLED Mass-fabrication System (대면적 유기EL 양산 장비 개발을 위한 증착 공정 모델링)

  • Lee, Eung-Ki
    • Journal of the Semiconductor & Display Technology
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    • v.5 no.4 s.17
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    • pp.29-34
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    • 2006
  • In order to design an OLED(Organic Luminescent Emitting Device) evaporation system, geometric simulation of film thickness distribution profile is required. For the OLED evaporation process, thin film thickness uniformity is of great practical importance. In this paper, a geometric modeling algorithm is introduced for process simulation of the OLED evaporating process. The physical fact of the evaporating process is modeled mathematically. Based on the developed method, the thickness of the thin-film layer can be successfully controlled.

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The Geometric Modeling for 3D Information of X-ray Inspection (3차원 정보 제공을 위한 X-선 검색장치의 기하학적 모델링)

  • Lee, Heung-Ho;Lee, Seung-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.8
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    • pp.1151-1156
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    • 2013
  • In this study, to clearly establish the concept of a geometric modeling I apply for the concept of Pushbroom, limited to two-dimensional radiation Locator to provide a three-dimensional information purposes. Respect to the radiation scanner Pushbroom modeling techniques, geometric modeling method was presented introduced to extract three-dimensional information as long as the rotational component of the Gamma-Ray Linear Pushbroom Stereo System, introduced the two-dimensional and three-dimensional spatial information in the matching relation that can be induced. In addition, the pseudo-inverse matrix by using the conventional least-squares method, GCP(Ground Control Point) to demonstrate compliance by calculating the key parameters. Projection transformation matrix is calculated for obtaining three-dimensional information from two-dimensional information can be used as the primary relationship, and through the application of a radiation image matching technology will make it possible to extract three-dimensional information from two-dimensional X-ray imaging.

A Study on the Analysis of Geometric Accuracy of Tilting Angle Using KOMPSAT-l EOC Images

  • Seo, Doo-Chun;Lim, Hyo-Suk
    • Korean Journal of Geomatics
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    • v.3 no.1
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    • pp.53-57
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    • 2003
  • As the Korea Multi-Purpose Satellite-I (KOMPSAT-1) satellite can roll tilt up to $\pm$45$^{\circ}$, we have analyzed some KOMPSAT-1 EOC images taken at different tilt angles for this study. The required ground coordinates for bundle adjustment and geometric accuracy are obtained from the digital map produced by the National Geography Institution, at a scale of 1:5,000. Followings are the steps taken for the tilting angle of KOMPSAT-1 to be present in the evaluation of geometric accuracy of each different stereo image data: Firstly, as the tilting angle is different in each image, the characteristic of satellite dynamic must be determined by the sensor modeling. Then the best sensor modeling equation should be determined. The result of this research, the difference between the RMSE values of individual stereo images is mainly due to quality of image and ground coordinates instead of tilt angle. The bundle adjustment using three KOMPSAT-1 stereo pairs, first degree of polynomials for modeling the satellite position, were sufficient.

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