Academic literature on the topic 'Cartesian coordinate system (3D)'

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Journal articles on the topic "Cartesian coordinate system (3D)"

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Jin, Xin, Xin Liu, Jinyun Guo, Maosheng Zhou, and Kezhi Wu. "A Novel All-Weather Method to Determine Deflection of the Vertical by Combining 3D Laser Tracking Free-Fall and Multi-GNSS Baselines." Remote Sensing 14, no. 17 (August 24, 2022): 4156. http://dx.doi.org/10.3390/rs14174156.

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The bright stars in the clear night sky with weak background lights should be observed in the traditional deflection of the vertical (DOV) measurement so that the DOV cannot be observed under all-weather conditions, which limits its wide applications. An all-weather DOV measurement method combining three-dimensional (3D) laser tracking free-fall and multi-GNSS baselines is proposed in this paper. In a vacuum environment, the 3D laser tracking technique is used to continuously track and observe the motion of free-fall with high frequency and precision for obtaining 3D coordinate series. The plumb line vector equation is established to solve the gravity direction vector in the coordinate system of the laser tracker at the measuring point using least squares fitting coordinate series. Multi-GNSS observations are solved for obtaining the precise geodetic cartesian coordinates of the measuring point and GNSS baseline information. A direction transformation method based on the baseline information proposed in this paper is used to convert the gravitational direction vector in the laser tracker coordinate system into the geodetic cartesian coordinate system. The geodetic cartesian coordinates of the measuring point are used to calculate the ellipsoid normal vector, and the angle between this and the gravity direction vector in the geodetic cartesian coordinate system is estimated to obtain the astrogeodetic DOV. The DOV is projected to the meridian and prime vertical planes to obtain the meridian and prime vertical components of the DOV, respectively. The astronomical latitude and longitude of the measuring point are calculated from these two components. The simulation experiments were carried out using the proposed method, and it was found that the theoretical precision of the DOV measured by the method could reach 0.2″, which could realise all-weather observation.
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Shulunov, Vyacheslav. "Transformation of 3D object into flat ribbon for RPS additive manufacturing technology." Rapid Prototyping Journal 23, no. 2 (March 20, 2017): 273–79. http://dx.doi.org/10.1108/rpj-11-2015-0164.

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Purpose This study aims to give a description of conformal transformation Cartesian coordinates into spiral coordinates using the example of roll powder sintering (RPS) additive manufacturing (AM) technology. RPS has several advantages over dominant AM processes currently available in the market. RPS allows accomplishing designs, which are impossible, very expensive and difficult to create by other methods. The technology requires slicing a 3D object with spiral scanning. Design/methodology/approach The paper describes the possibility of accurate 3D object transformation into a flat ribbon by spiral coordinate system. Parameters of conformal transformation are calculated according to the equation of equivalence between (x, y, z) and (l, z) coordinates. Findings As numerical examples show, it is possible to convert three-dimensional space to two-dimensional one if you know the thickness of the spatial layer. The proposed methodology can be used for the transformation of 3D computer-aided design models into 2D strip models. Originality/value In this paper, the author proposes a method of converting Cartesian coordinates into spiral coordinates. Conformal transformation of three-dimensional space to two-dimensional one by use of spiral coordinate system is demonstrated by RPS AM technology, which allows to produce objects with high accuracy.
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Zakarevičius, Algimantas, Vladislovas Česlovas Aksamitauskas, Algimantas Jakučionis, and Arminas Stanionis. "DETERMINATION OF GEOGRAPHIC POSITION OF OBJECT BY APPLYING 3D POLAR OBSERVATIONS." Aviation 14, no. 2 (June 30, 2010): 43–48. http://dx.doi.org/10.3846/aviation.2010.07.

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The geographic position of an object is determined by geodetic latitude, geodetic longitude, geodetic and normal height, and height of the object above the surface of the earth. To determine the geographic position of an object, a technologic scheme is recommended: by applying 3D polar observations, the 3D Cartesian coordinates of the object in the local horizontal coordinate system (for example, with an airport runway tied system) are determined; local horizontal 3D Cartesian coordinates are recomputed into the system of geocentric equatorial 3D Cartesian coordinates; the geodetic coordinates (geodetic latitude, geodetic longitude, and geodetic height) are computed from the geocentric equatorial 3D Cartesian coordinates; based on information about geodetic height and the digital geoid model, the normal height of the object is computed; and object height above the earth is computed from normal height and the digital terrain model. Algorithms for the realisation of this technologic scheme are presented. Santrauka Objekto geografine padetis apibūdinama geodezine platuma, geodezine ilguma, geodeziniu bei normaliniu aukščiais ir objekto aukščiu virš Žemes paviršiaus. Objekto geografinei padečiai nustatyti rekomenduojama tokia technologine schema: taikant erdvinius polinius matavimus, nustatomos objekto erdvines stačiakampes koordinates vietineje (pvz., oro uosto) horizontineje koordinačiu sistemoje; vietines horizontines erdvines stačiakampes koordinates perskaičiuojamos i geocentriniu ekvatoriniu erdviniu stačiakampiu koordinačiu sistema; pagal geocentrines ekvatorines erdvines stačiakampes koordinates apskaičiuojamos geodezines koordinates (geodezine platuma, geodezine ilguma ir geodezinis aukštis); žinant geodezini aukšti ir turint skaitmenini geoido modeli, skaičiuojamas objekto normalinis aukštis; turint normalini aukšti ir skaitmenini reljefo modeli, apskaičiuojamas objekto aukštis virš Žemes paviršiaus. Pateikiami algoritmai šiai technologinei schemai realizuoti.
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Shragge, Jeffrey. "Solving the 3D acoustic wave equation on generalized structured meshes: A finite-difference time-domain approach." GEOPHYSICS 79, no. 6 (November 1, 2014): T363—T378. http://dx.doi.org/10.1190/geo2014-0172.1.

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The key computational kernel of most advanced 3D seismic imaging and inversion algorithms used in exploration seismology involves calculating solutions of the 3D acoustic wave equation, most commonly with a finite-difference time-domain (FDTD) methodology. Although well suited for regularly sampled rectilinear computational domains, FDTD methods seemingly have limited applicability in scenarios involving irregular 3D domain boundary surfaces and mesh interiors best described by non-Cartesian geometry (e.g., surface topography). Using coordinate mapping relationships and differential geometry, an FDTD approach can be developed for generating solutions to the 3D acoustic wave equation that is applicable to generalized 3D coordinate systems and (quadrilateral-faced hexahedral) structured meshes. The developed numerical implementation is similar to the established Cartesian approaches, save for a necessary introduction of weighted first- and mixed second-order partial-derivative operators that account for spatially varying geometry. The approach was validated on three different types of computational meshes: (1) an “internal boundary” mesh conforming to a dipping water bottom layer, (2) analytic “semiorthogonal cylindrical” coordinates, and (3) analytic semiorthogonal and numerically specified “topographic” coordinate meshes. Impulse response tests and numerical analysis demonstrated the viability of the approach for kernel computations for 3D seismic imaging and inversion experiments for non-Cartesian geometry scenarios.
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Wang, Shu, and Yongxin Wang. "The Global Well-Posedness for Large Amplitude Smooth Solutions for 3D Incompressible Navier–Stokes and Euler Equations Based on a Class of Variant Spherical Coordinates." Mathematics 8, no. 7 (July 21, 2020): 1195. http://dx.doi.org/10.3390/math8071195.

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This paper investigates the globally dynamical stabilizing effects of the geometry of the domain at which the flow locates and of the geometry structure of the solutions with the finite energy to the three-dimensional (3D) incompressible Navier–Stokes (NS) and Euler systems. The global well-posedness for large amplitude smooth solutions to the Cauchy problem for 3D incompressible NS and Euler equations based on a class of variant spherical coordinates is obtained, where smooth initial data is not axi-symmetric with respect to any coordinate axis in Cartesian coordinate system. Furthermore, we establish the existence, uniqueness and exponentially decay rate in time of the global strong solution to the initial boundary value problem for 3D incompressible NS equations for a class of the smooth large initial data and a class of the special bounded domain described by variant spherical coordinates.
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Wei, Xiu Ting, Qiang Du, and Jing Cheng Liu. "The Application of UG NX Second Development in Centrifugal Pump Impeller Vane 3D Solid Modeling." Applied Mechanics and Materials 20-23 (January 2010): 1286–91. http://dx.doi.org/10.4028/www.scientific.net/amm.20-23.1286.

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The hydraulic model of the impeller and points of its vane surface given in the cylindrical coordinates, we can not directly use those data to accomplish the 3D solid modeling of the impeller in CAD systems. Based the Access and the UG NX, this paper puts forwards a new method for modeling centrifugal pump impeller vanes and presents the implementing procedure. And the method includes the following steps: 1) defining the data structure of hydraulic models; 2)converting the vane surface data from the cylindrical coordinate system to the cartesian coordinate system; 3)constructing the vane’s working surface and back surface along the axial transversals; 4) accomplishing the impeller’s 3D solid model by UG NX Second Development. The practical application demonstrates that the proposed method can shorten the cycle of impeller modeling and improve the design precision.
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Shragge, Jeffrey. "Acoustic wave propagation in tilted transversely isotropic media: Incorporating topography." GEOPHYSICS 81, no. 5 (September 2016): C265—C278. http://dx.doi.org/10.1190/geo2015-0311.1.

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Simulating two-way acoustic wavefield propagation directly from a free-surface boundary in the presence of topography remains a computational challenge for applications of reverse time migration (RTM) or full-waveform inversion (FWI). For land-seismic settings involving heavily reworked geology (e.g., fold and thrust belts), two-way wavefield propagation operators should also handle commonly observed complex anisotropy including tilted transversely isotropic (TTI) media. To address these issues, I have extended a system of coupled partial differential equations used to model 3D acoustic TTI wave propagation in Cartesian coordinates to more generalized 3D geometries, including a deformed computational mesh with a domain boundary conformal to free-surface topography. A generalized curvilinear transformation is used to specify a system of equations governing 3D acoustic TTI wave propagation in the “topographic” coordinate system. The developed finite-difference time-domain numerical solution adapts existing Cartesian TTI operators to this more generalized geometry with little additional computational overhead. Numerical evaluations illustrate that 2D and 3D impulse responses are well-matched to those simulated on Cartesian meshes and analytic traveltimes for homogeneous elliptical TTI media. Accordingly, these generalized acoustic TTI propagators and their numerical adjoints are useful for undertaking most RTM or FWI applications using computational domains conforming to free-surface topography.
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Filić, Mia, Renato Filjar, and Marko Ševrović. "Expression of GNSS Positioning Error in Terms of Distance." PROMET - Traffic&Transportation 30, no. 3 (July 2, 2018): 305–10. http://dx.doi.org/10.7307/ptt.v30i3.2304.

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This manuscript analyzes two methods for Global Navigation Satellite System positioning error determination for positioning performance assessment by calculation of the distance between the observed and the true positions: one using the Cartesian 3D rectangular coordinate system, and the other using the spherical coordinate system, the Cartesian reference frame distance method, and haversine formula for distance calculation. The study shows unresolved issues in the utilization of position estimates in geographical reference frame for GNSS positioning performance assessment. Those lead to a recommendation for GNSS positioning performance assessment based on original WGS84-based GNSS position estimates taken from recently introduced data access from GNSS software-defined radio (SDR) receivers.
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Shragge, Jeff, and Guojian Shan. "Prestack wave-equation depth migration in elliptical coordinates." GEOPHYSICS 73, no. 5 (September 2008): S169—S175. http://dx.doi.org/10.1190/1.2956349.

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We extend Riemannian wavefield extrapolation (RWE) to prestack migration using 2D elliptical-coordinate systems. The corresponding 2D elliptical extrapolation wavenumber introduces only an isotropic slowness model stretch to the single-square-root operator. This enables the use of existing Cartesian finite-difference extrapolators for propagating wavefields on elliptical meshes. A poststack migration example illustrates advantages of elliptical coordinates for imaging turning waves. A 2D imaging test using a velocity-benchmark data set demonstrates that the RWE prestack migration algorithm generates high-quality prestack migration images that are more accurate than those generated by Cartesian operators of the equivalent accuracy. Even in situations in which RWE geometries are used, a high-order implementation of the one-way extrapolator operator is required for accurate propagation and imaging. Elliptical-cylindrical and oblate-spheroidal geometries are potential extensions of the analytical approach to 3D RWE-coordinate systems.
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Vivi Melinda and Andree Emmanuel Widjaja. "Virtual Reality Applications in Education." International Transactions on Education Technology (ITEE) 1, no. 1 (November 29, 2022): 68–72. http://dx.doi.org/10.34306/itee.v1i1.194.

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Virtual reality (VR) is a computer-based simulation technology that enables users to interact while experiencing oneself in a virtual environment.Virtual reality (VR) combines three-dimensional (3D) objects combined with hearing and vision to create effects for users as if they were in a virtual environment. It should be noted here that the use of Virtual Reality is very effective in the field of education Given that a user can observe things in cyberspace from all angles, including above, below, to the left, right, back, and ahead, the 3D coordinate system used in virtual reality (VR) is based on the Cartesian coordinate system.
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Dissertations / Theses on the topic "Cartesian coordinate system (3D)"

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Culaciati, Marianna. "Three-dimensional tooth displacement following orthodontic, orthognathic and restorative treatment: mathematical analysis and case study." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12130.

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A single 3D virtual system in orthodontic-surgical and restorative patients has not been developed. The study aims were to evaluate: (1) the performance of a Cartesian coordinate system (CSYS) to measure translational and rotational tooth displacement, and (2) maxillary and mandibular tooth, occlusion and bone displacement with the CSYS and a lingual landmarks mathematical registration method. Eleven maxillary and mandibular dental models following an orthodontic surgical and restorative treatment sequence case were retrospectively collected. These were laser scanned and processed using reverse engineering computer aided design (CAD) technology to generate 3D models from which 6 paired models were evaluated. Phase one measured the errors in: (1) the correlation between CSYS – ABC landmarks (3 landmarks positioned on the anterior palate) selection and resulting tooth measurements, and (2) operator tooth landmark placement. Phase two: (1) used the maxillary and mandibular teeth landmarks to calculate the orthodontic, restorative and orthognathic translations and rotational displacement, (2) used additional registered landmarks on the lingual tori and mandibular teeth (when considered immobile) to isolate mandibular tooth displacement, and (3) calculated the inter-arch measurements. Relevant results indicated: (1) CSYS – ABC allocation mean translational deviation errors were small with 3D distance > anteroposterior > horizontal =vertical axes. Incisors were the least affected teeth, while molars the most affected. (2) Operator Landmarks selection error was negligible. (3) No statistical difference in tooth movement analysis for the mandible de-rotation methods was observed at the pre-surgical restorative stage. Customised CSYS and lingual landmarks of mandibular tori registration permits clinical orthodontic, restorative and orthognathic displacement measurement.
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Ahlman, Gustav. "Improved Temporal Resolution Using Parallel Imaging in Radial-Cartesian 3D functional MRI." Thesis, Linköpings universitet, Datorseende, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69123.

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MRI (Magnetic Resonance Imaging) is a medical imaging method that uses magnetic fields in order to retrieve images of the human body. This thesis revolves around a novel acquisition method of 3D fMRI (functional Magnetic Resonance Imaging) called PRESTO-CAN that uses a radial pattern in order to sample the (kx,kz)-plane of k-space (the frequency domain), and a Cartesian sample pattern in the ky-direction. The radial sample pattern allows for a denser sampling of the central parts of k-space, which contain the most basic frequency information about the structure of the recorded object. This allows for higher temporal resolution to be achieved compared with other sampling methods since a fewer amount of total samples are needed in order to retrieve enough information about how the object has changed over time. Since fMRI is mainly used for monitoring blood flow in the brain, increased temporal resolution means that we can be able to track fast changes in brain activity more efficiently.The temporal resolution can be further improved by reducing the time needed for scanning, which in turn can be achieved by applying parallel imaging. One such parallel imaging method is SENSE (SENSitivity Encoding). The scan time is reduced by decreasing the sampling density, which causes aliasing in the recorded images. The aliasing is removed by the SENSE method by utilizing the extra information provided by the fact that multiple receiver coils with differing sensitivities are used during the acquisition. By measuring the sensitivities of the respective receiver coils and solving an equation system with the aliased images, it is possible to calculate how they would have looked like without aliasing.In this master thesis, SENSE has been successfully implemented in PRESTO-CAN. By using normalized convolution in order to refine the sensitivity maps of the receiver coils, images with satisfying quality was able to be reconstructed when reducing the k-space sample rate by a factor of 2, and images of relatively good quality also when the sample rate was reduced by a factor of 4. In this way, this thesis has been able to contribute to the improvement of the temporal resolution of the PRESTO-CAN method.
MRI (Magnetic Resonance Imaging) är en medicinsk avbildningsmetod som använder magnetfält för att framställa bilder av människokroppen. Detta examensarbete kretsar kring en ny inläsningsmetod för 3D-fMRI (functional Magnetic Resonance Imaging) vid namn PRESTO-CAN som använder ett radiellt mönster för att sampla (kx,kz)-planet av k-rummet (frekvensdomänen), och ett kartesiskt samplingsmönster i ky-riktningen. Det radiella samplingsmönstret möjliggör tätare sampling av k-rummets centrala delar, som innehåller den mest grundläggande frekvensinformationen om det inlästa objektets struktur. Detta leder till att en högre temporal upplösning kan uppnås jämfört med andra metoder eftersom det krävs ett mindre antal totala sampel för att få tillräcklig information om hur objektet har ändrats över tid. Eftersom fMRI framförallt används för att övervaka blodflödet i hjärnan innebär ökad temporal upplösning att vi kan följa snabba ändringar i hjärnaktivitet mer effektivt.Den temporala upplösningen kan förbättras ytterligare genom att minska scanningstiden, vilket i sin tur kan uppnås genom att tillämpa parallell avbildning. En metod för parallell avbildning är SENSE (SENSitivity Encoding). Scanningstiden minskas genom att minska samplingstätheten, vilket orsakar vikning i de inlästa bilderna. Vikningen tas bort med SENSE-metoden genom att utnyttja den extra information som tillhandahålls av det faktum att ett flertal olika mottagarspolar med sinsemellan olika känsligheter används vid inläsningen. Genom att mäta upp känsligheterna för de respektive mottagarspolarna och lösa ett ekvationssystem med de vikta bilderna är det möjligt att beräkna hur de skulle ha sett ut utan vikning.I detta examensarbete har SENSE framgångsrikt implementerats i PRESTO-CAN. Genom att använda normaliserad faltning för att förfina mottagarspolarnas känslighetskartor har bilder med tillfredsställande kvalitet varit möjliga att rekonstruera när samplingstätheten av k-rummet minskats med en faktor 2, och bilder med relativt bra kvalitet också när samplingstätheten minskats med en faktor 4. På detta sätt har detta examensarbete kunnat bidra till förbättrandet av PRESTO-CAN-metodens temporala upplösning.
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Alkhadour, Wissam M. "Reconstruction of 3D scenes from pairs of uncalibrated images. Creation of an interactive system for extracting 3D data points and investigation of automatic techniques for generating dense 3D data maps from pairs of uncalibrated images for remote sensing applications." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4933.

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Much research effort has been devoted to producing algorithms that contribute directly or indirectly to the extraction of 3D information from a wide variety of types of scenes and conditions of image capture. The research work presented in this thesis is aimed at three distinct applications in this area: interactively extracting 3D points from a pair of uncalibrated images in a flexible way; finding corresponding points automatically in high resolution images, particularly those of archaeological scenes captured from a freely moving light aircraft; and improving a correlation approach to dense disparity mapping leading to 3D surface reconstructions. The fundamental concepts required to describe the principles of stereo vision, the camera models, and the epipolar geometry described by the fundamental matrix are introduced, followed by a detailed literature review of existing methods. An interactive system for viewing a scene via a monochrome or colour anaglyph is presented which allows the user to choose the level of compromise between amount of colour and ghosting perceived by controlling colour saturation, and to choose the depth plane of interest. An improved method of extracting 3D coordinates from disparity values when there is significant error is presented. Interactive methods, while very flexible, require significant effort from the user finding and fusing corresponding points and the thesis continues by presenting several variants of existing scale invariant feature transform methods to automatically find correspondences in uncalibrated high resolution aerial images with improved speed and memory requirements. In addition, a contribution to estimating lens distortion correction by a Levenberg Marquard based method is presented; generating data strings for straight lines which are essential input for estimating lens distortion correction. The remainder of the thesis presents correlation based methods for generating dense disparity maps based on single and multiple image rectifications using sets of automatically found correspondences and demonstrates improvements obtained using the latter method. Some example views of point clouds for 3D surfaces produced from pairs of uncalibrated images using the methods presented in the thesis are included.
Al-Baath University
The appendices files and images are not available online.
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Alkhadour, Wissam Mohamad. "Reconstruction of 3D scenes from pairs of uncalibrated images : creation of an interactive system for extracting 3D data points and investigation of automatic techniques for generating dense 3D data maps from pairs of uncalibrated images for remote sensing applications." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4933.

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Much research effort has been devoted to producing algorithms that contribute directly or indirectly to the extraction of 3D information from a wide variety of types of scenes and conditions of image capture. The research work presented in this thesis is aimed at three distinct applications in this area: interactively extracting 3D points from a pair of uncalibrated images in a flexible way; finding corresponding points automatically in high resolution images, particularly those of archaeological scenes captured from a freely moving light aircraft; and improving a correlation approach to dense disparity mapping leading to 3D surface reconstructions. The fundamental concepts required to describe the principles of stereo vision, the camera models, and the epipolar geometry described by the fundamental matrix are introduced, followed by a detailed literature review of existing methods. An interactive system for viewing a scene via a monochrome or colour anaglyph is presented which allows the user to choose the level of compromise between amount of colour and ghosting perceived by controlling colour saturation, and to choose the depth plane of interest. An improved method of extracting 3D coordinates from disparity values when there is significant error is presented. Interactive methods, while very flexible, require significant effort from the user finding and fusing corresponding points and the thesis continues by presenting several variants of existing scale invariant feature transform methods to automatically find correspondences in uncalibrated high resolution aerial images with improved speed and memory requirements. In addition, a contribution to estimating lens distortion correction by a Levenberg Marquard based method is presented; generating data strings for straight lines which are essential input for estimating lens distortion correction. The remainder of the thesis presents correlation based methods for generating dense disparity maps based on single and multiple image rectifications using sets of automatically found correspondences and demonstrates improvements obtained using the latter method. Some example views of point clouds for 3D surfaces produced from pairs of uncalibrated images using the methods presented in the thesis are included.
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Naser, Inam. "Rotated Polar Coordinate system, its Solid Vector Mathematical Operations, and 3-D Unsharp Masking and Gradient-Based Laplacian Spatial Filters of a Field of Vectors for Geometrical Edges Detection." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592135647774656.

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Soares, Vanessa Ribeiro. "Batalha naval e suas aplicações." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/5909.

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This work has the purpose contribute to the improvement in some teaching contents of analytic geometry and trigonometry in high school . The content work was based on the National Curriculum Parameters, highlighting de nitions, theorems and properties necessary for the development of student learning. The theme was chosen after a practical experience involving the Naval Battle game in order to reduce the students' di culties. The playful work, as the game, has a practical application that does the student become familiar with the content. That's an interesting way to propose problems and solutions involving the content. Thus becomes something attractive to the student and encourages creativity in nding problems solutions.
O trabalho tem como objetivo contribuir para o aprimoramento no ensino de alguns conteúdos de Geometria Analítica e Trigonometria no Ensino Médio. Dentro dos Parâmetros Curriculares Nacionais, trabalhamos o conteúdo destacando de nições, teoremas e propriedades necessárias para o desenvolvimento de aprendizagem do aluno. O tema foi escolhido depois de uma experiência prática envolvendo o jogo Batalha Naval a m de diminuir as di culdades dos alunos. O trabalho lúdico, como o jogo, tem uma aplicação prática que faz o aluno se familiarizar com os conceitos. É uma forma interessante de propor problemas e soluções envolvendo o conceitos. Assim se torna algo atrativo para o aluno e favorece a criatividade na busca de soluções para os problemas.
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Stålberg, Martin. "Reconstruction of trees from 3D point clouds." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316833.

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The geometrical structure of a tree can consist of thousands, even millions, of branches, twigs and leaves in complex arrangements. The structure contains a lot of useful information and can be used for example to assess a tree's health or calculate parameters such as total wood volume or branch size distribution. Because of the complexity, capturing the structure of an entire tree used to be nearly impossible, but the increased availability and quality of particularly digital cameras and Light Detection and Ranging (LIDAR) instruments is making it increasingly possible. A set of digital images of a tree, or a point cloud of a tree from a LIDAR scan, contains a lot of data, but the information about the tree structure has to be extracted from this data through analysis. This work presents a method of reconstructing 3D models of trees from point clouds. The model is constructed from cylindrical segments which are added one by one. Bayesian inference is used to determine how to optimize the parameters of model segment candidates and whether or not to accept them as part of the model. A Hough transform for finding cylinders in point clouds is presented, and used as a heuristic to guide the proposals of model segment candidates. Previous related works have mainly focused on high density point clouds of sparse trees, whereas the objective of this work was to analyze low resolution point clouds of dense almond trees. The method is evaluated on artificial and real datasets and works rather well on high quality data, but performs poorly on low resolution data with gaps and occlusions.
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Chen, Jie. "Spatiotemporal roles of retinoic acid signaling in the cephalochordate amphioxus." Thesis, Lyon, École normale supérieure, 2011. http://www.theses.fr/2011ENSL0605.

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L'acide rétinoïque (AR) est un morphogène dérivé de la vitamine A, qui intervient dans le contrôle de l'organogenèse, de la prolifération et de la différenciation cellulaires chez les Chordés. Dans ce contexte, nous avons étudié les régulations spatio-temporelles de la voie de signalisation de l’AR au cours du développement de l’amphioxus, en mettant l'accent sur l’espèce européenne Branchiostoma lanceolatum.Nous avons tout d'abord inhibé ou activé la voie de signalisation de l’AR lors du développement embryonnaire en traitant des embryons d’amphioxus à des doses variables de composés pharmacologiques interférant avec le métabolisme des rétinoïdes. Grâce à l’utilisation d’outils mathématiques spécifiques, nous avons établi un schéma détaillé des effets des traitements effectués sur le développement du système nerveux central (SNC) et du pharynx chez l’amphioxus en nous basant sur l’expression de gènes marqueurs de tissus spécifiques. À l’issue de cette première analyse, nous avons par la suite étudié les effets d’une perturbation de la signalisation de l’AR à des points clés du développement chez l’amphioxus lors de la régionalisation du SNC et du pharynx. Nous avons ainsi montré que la voie de signalisation de l’AR intervient dans la régionalisation de l’axe antéro-postérieur via le contrôle des gènes hox dès le stade gastrula et jusqu’aux stades larvaires. En outre, nous avons réalisé l'étude préliminaire du gène homologue chez l’amphioxus du gène aldh1a2 des Vertébrés, et avons démontré que la régulation du niveau de synthèse de l’AR au cour du développement est conservée entre l’amphioxus et les Vertébrés. Finalement, nous avons montré que la voie de l’AR participe également à la morphogenèse caudale chez l’amphioxus, et que le mécanisme impliqué semble différent de celui proposé chez les Vertébrés où l’AR contrôle la structuration de la nageoire caudale par le ciblage des tissus mésenchymateux
Retinoic acid (RA) is an endogenous vitamin A-derived morphogen. In this context, we studied the spatiotemporal roles of RA signaling in amphioxus development, focusing on the European amphioxus species: Branchiostoma lanceolatum. We first created excess and insufficiency models of RA signaling by exposing amphioxus embryos to series of doses of different pharmacological compounds targeting either the RA receptors or the RA metabolism machinery. By introducing the important mathematical concept of a Cartesian coordinate system founded by René Descartes, we created detailed diagrams of the concentration-dependent defects caused by RA signaling in the central nervous system (CNS) and pharynx of amphioxus by evaluating the statistical significances of tissue-specific marker gene expression in labeled embryos. This analysis yielded a very detailed description of the sensitivities of the developing amphioxus CNS and pharynx to altered RA signaling levels. Following this initial challenge, we correlated the effects of altered RA signaling levels with key amphioxus developmental stages characterized by structural transitions in CNS and pharynx. We show that hox-mediated RA signaling in axial patterning is active beyond the gastrula stage and might be maintained until at least early larval stage, with possible roles in more regionalized axis formation and organ induction. In addition, we carried out a preliminary study on a RA synthesizing gene in amphioxus, called aldh1a, a possible homolog of the vertebrate aldh1a2 gene, demonstrating that the feedback between RA signaling and RA synthesizing levels has emerged before the split of the cephalochordate and vertebrate lineages. Moreover, we are able to show that RA signaling also participates in tail fin morphogenesis in amphioxus by a mechanism that is probably not comparable to that in vertebrates, where RA modulates caudal fin patterning through targeting mesenchymal derivatives
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Chang, Kai Yao, and 張凱堯. "A Two-Dimensional Model of Gradually Varied Unsteady Bend Channel Flow in Cartesian Coordinate System." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/34348572965473199341.

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Zhang, Chun-Chieh, and 張俊傑. "The Design and Development of Scratch Programming Language for "Cartesian Coordinate System" and "line equation" Course." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/07194445437363350611.

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碩士
淡江大學
教育科技學系數位學習在職專班
100
The aim of the study is to design and construct a teaching material for learning the mathematical Scratch Programming Language developed specific for junior high school students. Design-Based Research was used as the research theory and the basis of teaching material development. By utilizing seventh graders’ mathematics lessons, students were guided to use the Visualization Tool Scratch Programming Language. Through the problem-solving based learning process, it ignited students’ learning motivations as well as increased learning effectiveness. As the theme of the developed material integrates with “Cartesian Coordinate System” and “Linear Equation” of seventh graders’ Mathematics curriculum, it did not only enable students to enjoy the fun of designing IT programming language, but also repetitively revise, test and verify the mathematical concepts of “Cartesian Coordinate System” and “Linear Equation”, which were often considered difficult for students to grasp, during the learning process. Experimental teaching sessions were carried out for this particular teaching material, and conclusions are listed as below: 1. Students had Scratch integrated in their mathematics curriculum performed better in their learning achievement test compared to students in the control group. 2. Students had Scratch integrated in their mathematics curriculum performed better in their learning achievement procrastinated test compared to students in the control group. 3. Positive feedbacks were received from students on the integration of Scratch in their mathematics curriculum.
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Books on the topic "Cartesian coordinate system (3D)"

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Jeutner, Valentin. Introduction. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198808374.003.0001.

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This part introduces and illustrates the idea of a legal dilemma by means of a hypothetical Cartesian coordinate system. The introduction alsosets out the objectives of the book. It does so with reference to three research questions concerning, first, the definition of a legal dilemma, second, the possibility of the existence of a legal dilemma, and, finally, the way in which the international legal order should address legal dilemmas. Subsequently, the introduction outlines five examples to which the book keeps referring. The examples concern the regulation of nuclear weapons, submarine warfare, military alliances, conflicting infrastructure treaties, and the rescue of persons in distress at sea.
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Book chapters on the topic "Cartesian coordinate system (3D)"

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Liu, Yanmin, Zhuanzhou Zhang, Yuanfeng Luo, and Xiangbiao Wu. "PSO Based on Cartesian Coordinate System." In Intelligent Computing in Bioinformatics, 363–70. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09330-7_43.

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Jain, Anita, and Kavita Khare. "3D CORDIC Algorithm Based Cartesian to Spherical Coordinate Converter." In Communications in Computer and Information Science, 337–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-42024-5_40.

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Chung, Y. H. "Teaching Thermodynamic Relations Using a Story and Two-Dimensional Cartesian Coordinate System." In Chemistry Education in the ICT Age, 19–25. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-9732-4_3.

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Poliakovsky, Arkady. "The Total Simplified Lagrangian of the Gravity in a Cartesian Coordinate System." In Lorentzian Geometrical Structures with Global Time, Gravity and Electrodynamics, 65–76. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-23762-1_4.

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Biswas, Ranita, Gaëlle Largeteau-Skapin, Rita Zrour, and Eric Andres. "Rhombic Dodecahedron Grid—Coordinate System and 3D Digital Object Definitions." In Discrete Geometry for Computer Imagery, 27–37. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-14085-4_3.

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Dangel, R. J. Z., T. Schmitz-Rode, and C. Disselhorst-Klug. "Modelling of Eye-Hand Motions in a Common 3D Coordinate System." In IFMBE Proceedings, 212–15. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03882-2_56.

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Liu, S. G., K. Peng, F. S. Huang, Guo Xiong Zhang, and P. Li. "A Portable 3D Vision Coordinate Measurement System Using a Light Pen." In Key Engineering Materials, 331–36. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-977-6.331.

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Zhao, Huan, Wei Li, Lei Wang, Xin Ling, Dandan Shan, Bing Li, and Zhan Su. "Research on the Permeability Model of Fractal Fractured Media in 3D Coordinate System." In Computational and Experimental Simulations in Engineering, 1147–55. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-27053-7_98.

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Poliakovsky, Arkady. "The Euler-Lagrange for the Lagrangian of the Gravitational and Electromagnetic Fields in a Cartesian Coordinate System." In Lorentzian Geometrical Structures with Global Time, Gravity and Electrodynamics, 81–91. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-23762-1_6.

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Poliakovsky, Arkady. "Gravity Field of Spherically Symmetric Massive Resting Body in a Coordinate System Which Is Cartesian and Inertial Simultaneously." In Lorentzian Geometrical Structures with Global Time, Gravity and Electrodynamics, 93–104. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-23762-1_7.

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Conference papers on the topic "Cartesian coordinate system (3D)"

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Hirokawa, Keishun, Kosuke Hayashi, Akira Sou, Akio Tomiyama, and Naoki Takada. "Numerical Simulation of Single Drops in a Vertical Pipe Using Various Coordinate Systems." In ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37491.

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The effects of the diameter ratio λ (= d/D, where d and D are the diameters of a drop and a pipe, respectively), the Morton number M and the viscosity ratio κ (= μd/μc, where μ is the viscosity and the subscripts d and c are the dispersed fluid particle and the continuous phase, respectively) on terminal velocities and shapes of single drops rising through stagnant liquids in a vertical pipe are investigated experimentally. Then, the drops in the pipe are simulated using a volume tracking method with various coordinate systems, i.e., three-dimensional (3D) cylindrical coordinates, 3D general curvilinear coordinates and 3D Cartesian coordinates. Predicted velocities and shapes of the drops using three coordinate systems are compared with the measured data to examine the effects of coordinate systems on the accuracy of prediction. As a result, (1) The velocity ratio VT/VT0 (VT and VT0 are the terminal velocity in a pipe and infinite liquid, respectively) decreases as λ increases, and it depends not only on λ but also on M and κ, (2) Good predictions for the terminal velocities and shapes of drops are obtained not only with cylindrical coordinates and curvilinear coordinates but also with Cartesian coordinates, provided that the spatial resolution is high, (3) When the spatial resolution is low, effects of coordinate systems on a drop shape are larger for Cartesian coordinate systems than for cylindrical coordinate and general curvilinear coordinate systems, and (4) Errors in predicted drop velocities are not so large even with very low spatial resolution.
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Siddappaji, Kiran, Mark G. Turner, Soumitr Dey, Kevin Park, and Ali Merchant. "Optimization of a 3-Stage Booster: Part 2—The Parametric 3D Blade Geometry Modeling Tool." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46664.

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A parametric approach for blade geometry design has been developed to obtain 3D blade models. The geometry of the blade is defined by a basic set of parameters that are first obtained from an axisymmetric solver. These parameters include the leading edge meridional coordinates, flow angles, axial chord, and the meridional coordinates of streamlines. Other parameters such as thickness to chord ratio need to be defined. Using these parameters the 2D airfoils are created and are stacked radially using one of the many multiple options that define the stacking axes from several additional parameters. The tool produces the desired number of 2D sections in a normalized coordinate system. Each blade section is then transformed to a 3D Cartesian coordinate system. Using Unigraphics-NX (CAD package), these sections are lofted and a 3D blade model is obtained. Parametric update of the spline points defining the 3D blade sections results in new blade shapes without going directly back into the CAD system. The importing of the geometry into a CFD solver, and a finite element solver to determine mode shapes and stresses is demonstrated. Full details of the blade procedure is presented for a 3-Stage Booster design. This parametric approach for defining blade geometry and how it lays a groundwork for a high-fidelity optimization procedure is described.
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Siddappaji, Kiran, Mark G. Turner, and Ali Merchant. "General Capability of Parametric 3D Blade Design Tool for Turbomachinery." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69756.

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A design tool for generating 3D blades for various turbomachinery applications using a parametric approach has been developed. The tool can create a variety of 3D blade geometries based on only a few basic parameters and limited interaction with a CAD system. A general approach for creating the blade geometries is implemented which makes it robust and easy to create different 3D blade shapes for various turbomachinery components. The geometric and aerodynamic parameters are used to create 2D airfoils and these airfoils are stacked on the desired stacking axis. The tool generates a specified number of 2D blade sections in a 3D Cartesian coordinate system. These sections can be lofted in a CAD package to obtain a solid 3D blade model, which has been demonstrated using Unigraphics-NX and Solidworks. The geometry modeler can also be used for generating 3D blades with special features like bent tip, split tip and other concepts, which can be explored with minimum changes to the blade geometry. The use of control points for the definition of splines makes it easy to modify the blade shapes quickly and smoothly to obtain the desired blade model. Blade shapes for axial turbomachines, radial turbomachines and wind turbines are generated to show the general capability of the tool. Other novel blade shapes are also shown which shows the full utility of this tool when integrated with CAD. The executable of the code that generates sections is freely available on the web.
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Kim, Kwangwon, Jaehyung Ju, and Doo-Man Kim. "Three-Dimensional Compliant Cellular Materials: A Mechanism Based Material Design." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36567.

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Cellular materials have two important properties: structures and mechanisms. These properties have important applications in materials design; in particular, they’re used to determine the modulus and yield strain. The objective of this study is to gain a better understanding of these two properties and to explore the synthesis of three-dimensional (3D) compliant cellular materials (CCMs) with compliant porous structures (CPSes) generated from modified hexagonal honeycombs. An orthotropic constitutive CCM model in the Cartesian coordinate system is constructed using the strain energy method, which uses the deformation of hinges around holes and the rotation of links. A finite element (FE) based simulation is conducted to validate the analytical model. The moduli and yield strains of the 3D CCMs with an aluminum alloy are about 1.2GPa and 0.4% in the longitudinal direction and about 0.08MPa and 30% in the lateral direction. The CCMs have extremely high positive and negative Poisson’s ratios νxy*∼±30 due to the large rotation of the link member in the transverse direction caused by an input displacement in the longitudinal direction. This paper demonstrates that compliant me so structures can be used for next generation materials design in tailoring mechanical properties such as moduli, strength, strain, and Poisson’s ratios.
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Zhu, Na, and Sean Wu. "Track and Trace Multiple Incoherent Sound Sources in 3D Space in Real Time." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-13181.

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This paper presents a methodology for tracking and tracing multiple incoherent sound sources in 3D space in real time. A salient feature of this methodology is its capability of handling all types of sound signals, including broadband, narrowband, continuous, impulsive, and tonal (sinusoidal) sounds over the audible frequency range (20 to 20,000 Hz). Locations of sound sources are indicated in terms of the Cartesian coordinates in real time. The target sources are viewed through an automatic tracking camera covering 350 degree solid angle. The hardware includes four microphones, a thermometer, a webcam, a five-channel signal conditioner and a laptop. Thus, the system can be made light, portable, easy to setup and use and inexpensive. The underlying algorithm is a hybrid approach consisting of modeling of sound radiation from a point source in a free field, triangulation and signal processing techniques. To acquire better understanding of the performance of the device, numerical simulations are conducted to study the impacts of signal noise ratio, microphone spacing, source distance and frequency on the spatial resolution and accuracy of the results. Experiments are carried out to validate results over a wide variety of real-world sound signals such as helicopter noise, human conversations, truck pass-by noise, gun shots, impact sounds, clapping, coughing, etc. Satisfactory results are obtained in most cases, even when a source is behind the measurement microphones.
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Khoda, Bashir, Ibrahim T. Ozbolat, and Bahattin Koc. "Modeling and Fabrication of Hollowed Scaffolds With Interconnected Variational Porosity Architecture." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64666.

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This paper presents a novel computer-aided modeling of 3D hollowed tissue scaffolds with a controlled internal architecture. Functionally gradient variational porosity architecture is proposed with continuous material deposition planning scheme. The complex internal architecture of scaffolds is discritized into sub-regions accumulated from ruling lines that are generated from outer to inner features. The desired pore size and hence the porosity have been achieved by geometrically partitioning those sub-regions based on the area while meeting the tissue scaffold design constraint. Thus the desired controlled variational porosity along the scaffold architecture has been achieved with the combination of two geometrically oriented consecutive layers. A continuous, interconnected and optimized tool-path has been generated for both layers aiming at the standard solid free form fabrication process. A zigzag pattern tool-path has been proposed for accumulated sub-region layer. And a concentric spiral like optimal tool-path pattern has been derived for the successive layer to ensure fabricatable continuity along the structure. A micro-nozzle biomaterial deposition system driven by NC motion control has been used to fabricate sample designed structure with desired pore size and porosity level. Besides proper characterization of the fabrication sample has been performed to validate the proposed methodology. Moreover a comparative study between proposed design and conventional cartesian coordinate scaffolds has been performed. The results demonstrate significant reduction in design error with the proposed method.
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Chuang, C. T., M. J. Kuo, and M. C. Lu. "Digital image on Cartesian coordinate convert system." In International conference on Communication Technology and Application. Southampton, UK: WIT Press, 2014. http://dx.doi.org/10.2495/cta140361.

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Aras, Eyyup. "Tool Contact Maps by Rectangular Grid Decomposition." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48668.

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This paper is intended to contribute to ongoing research [1–3] in geometric modeling of the virtual machining. In geometric modeling the tool paths are verified by performing the machining simulations and also the cutter workpiece engagements (CWEs) are extracted. CWE geometry is a key input to force calculations and feed rate scheduling in milling operations. Finding these engagements is challenging due to the complicated and changing intersection geometry between the cutter and the in-process workpiece. This paper presents a discrete model based methodology for extracting CWEs generated during a multi axis machining of free form surfaces using a range of different types of milling tools. In this method the in-process workpiece is represented by a set of z-axis aligned rectangular grids. Each grid is made up of four planes, with their normals aligned with respect to the x and y-axis of the Cartesian coordinate system. In developing the methodology the parametric representations of the automatically programmed tool (APT)-type milling cutters are used. The milling tool surfaces are decomposed into circles. During the material removal process only some portions of those circles which are called the engagement arcs may contact the in-process workpiece. To find the geometric limits of those arcs the concept of the feasible contact surface is utilized. The CWE extraction simulation is performed through intersecting those arcs with the planes of each rectangular grid. Thus the intersection calculations reduce to circle/plane intersections which can be performed analytically for the geometry found on milling cutters. To be used in the force model, the CWE boundaries are mapped from Euclidean 3D space to a parametric space defined by the engagement angle and the depth-of-cut for a given tool geometry. Then using a sort algorithm the neighboring engagements in the same arc level are combined.
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Raju, Vomsheendhur, and Majura F. Selekwa. "Autonomous Topographic Mapping of Unknown Environments by Dynamic Visual Data." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95497.

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Abstract The simultaneous localization and mapping (SLAM) process is what makes it possible for autonomous vehicles to navigate in unknown environments. Early SLAM algorithms used and relied on ranging sensors only. In recent years, there has been an increased interest in vision-based SLAM (V-SLAM) due to the low-cost nature of digital cameras available in the market compared to ranging sensors. V-SLAM uses successive camera frames to either track features in individual frames and triangulates the position to construct a 3-D map or determine the vehicle speed by measuring the rate of change of these features relative to a known reference. This paper proposes an effective real-time method of creating a topological 3D map of the environment from a stereo vision system by using an improved stereo correspondence algorithm that minimizes errors caused by illumination and texture variation in the disparity map generation. The Cartesian world coordinates corresponding to each pixel are computed from the disparity map generated by triangulating the depth of the pixels in the reference perspective projection image to create a 3-D map of the scene as a point cloud plot. Analysis of the resulting point cloud plot indicates that the coordinates of each pixel provide the 3-D information about the scene representing a working topological map that can be used to detect the obstacles in close vicinity to the robot.
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Chuang, Chin-Tun, Cheng-Pei Tsai, Tien-Yu Tang, and Yu-An Cho. "Label System on Cartesian Coordinate by Using a Digital Camera." In 2010 International Conference on Internet Technology and Applications (iTAP). IEEE, 2010. http://dx.doi.org/10.1109/itapp.2010.5566356.

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