يمكن بروتوكول المصادقة القابل للإنكار المستقبل من التعرف على المصدر الحقيقي لأي رسالة بعينها، ولكنه لا يمكن الطرف الثالث من إثبات هوية المرسل. تعتبر تلك الخاصية مفيدة جدا في توفير تفاوض آمن عبر شبكة الإنترنت. تصف الورقة العلمية الحالية بروتوكول المصادقة غير التفاعلي والقابل للإنكار باستخدام نظام تواقيع خوارزمية التوقيع الرقمي ذو المنحنى الإهليجي (ECDSA). تعتمد مسألة الأمان في هذا البروتوكول على صعوبة كسر مسألة الخوارزميات المتقطعة ذات المنحى الإهليجي (ECDLP). يمكن تطبيق ذلك البروتوكول في الأجهزة المتنقلة منخفضة الطاقة وذات المعالجات الصغيرة كالبطاقات الذكية، وأجهزة المساعدة الشخصية، ... الخ.
International Journal of Shape ModelingVol. 16, No. 01n02, pp. 1-7 (2010) No AccessEDITORIAL: CONTENT-SENSITIVE METHODS FOR GEOMETRIC MODELINGSONG YU, IMRE HORVÁTH, and FERRUCCIO MANDORLISONG YU Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands, IMRE HORVÁTHFaculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands, and FERRUCCIO MANDORLIFaculty of Engineering, Università Politecnica delle Marche, Via Brecce Bianche, Ancona, Italyhttps://doi.org/10.1142/S0218654310001250Cited by:1 Next AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail References I. Horváth , Shifting paradigms of computer aided design ( Delft University Press , 1998 ) . Google Scholar M. E. Mortenson , Geometric modeling , 3rd edn. ( Industrial Press , 2006 ) . Google ScholarP. Min, M. Kazhdan and T. Funkhouser, A comparison of text and shape matching for retrieval of online 3D models, European Conference on Digital Libraries pp. 209–220. Google ScholarT. Igarashi, S. Matsuoka and H. Tanaka, Teddy: A sketching interface for 3D freeform design, SIGGRAPH'99 pp. 409–416. Google Scholar J. Lee and T. Funkhouser , Sketch-based search and composition of 3D models , EUROGRAPHICS Workshop on Sketch-Based Interfaces and Modeling . Google ScholarJ. Lee and J. Park, International Journal of CAD/CAM 7(1), (2007). Google ScholarJ. Pu and D. Gur, Computer Aided Design 41(12), 857 (2009), DOI: 10.1016/j.cad.2009.05.005. Crossref, Google Scholar X. Chen, A. Golovinskiy, and T. Funkhouser, A benchmark for 3D mesh segmentation, ACM Transactions on Graphics, SIGGRAPH'09, 28(3) (Aug. 2009) . Google ScholarJ. W. H. Tangelder and R. C. Veltkamp, Multimedia Tools and Applications 39(3), 441 (2008), DOI: 10.1007/s11042-007-0181-0. Crossref, Google ScholarR. Gal and D. Cohen-Or, ACM Transactions on Graphics 25(1), 130 (2006), DOI: 10.1145/1122501.1122507. Crossref, Google ScholarI. E. Berezhnoy, E. O. Postma and H. J. van den Herik, Machine Vision and Applications 20(1), 1 (2009), DOI: 10.1007/s00138-007-0098-7. Crossref, Google ScholarY. Xiang, J. Arora and K. Abdel-Malek, Journal of biomechanics (2010). Google Scholar G. Gerlach , W. Dotzel and D. Müller , Introduction to microsystem technology, A guide for students , Microsystem and Nanotechnology Series ( Wileyl , 2008 ) . Google ScholarB. Tamadazteet al., The International Journal of Robotics Research 29(11), 1416 (2010), DOI: 10.1177/0278364910376033. Crossref, Google ScholarD. Baowan, B. J. Cox and J. M. Hill, Nanotechnology 19(7), (2008), DOI: 10.1088/0957-4484/19/7/075704. Google Scholar FiguresReferencesRelatedDetailsCited By 1D3AdvM: A direct 3D adversarial sample attack inside mesh dataHuangxinxin Xu, Fazhi He, Linkun Fan and Junwei Bai1 Aug 2022 | Computer Aided Geometric Design, Vol. 97 Recommended Vol. 16, No. 01n02 Metrics History PDF download
The tensorial Bernstein basis for multivariate polynomials in n variables has a number 3n of functions for degree 2. Consequently, computing the representation of a multivariate polynomial in the tensorial Bernstein basis is an exponential time algorithm, which makes tensorial Bernstein-based solvers impractical for systems with more than n = 6 or 7 variables. This article describes a polytope (Bernstein polytope) with a number of faces, which allows to bound a sparse, multivariate polynomial expressed in the canonical basis by solving several linear programming problems. We compare the performance of a subdivision solver using domain reductions by linear programming with a solver using a change to the tensorial Bernstein basis for domain reduction. The performance is similar for n = 2 variables but only the solver using linear programming on the Bernstein polytope can cope with a large number of variables. We demonstrate this difference with two formulations of the forward kinematics problem of a Gough-Stewart parallel robot: a direct Cartesian formulation and a coordinate-free formulation using Cayley-Menger determinants, followed by a computation of Cartesian coordinates. Furthermore, we present an optimization of the Bernstein polytope-based solver for systems containing only the monomials xi and . For these, it is possible to obtain even better domain bounds at no cost using the quadratic curve (xi, ) directly.
The paper introduces the concept of functional segmentation for segregating the strokes in a product concept sketch into functionally meaningful groups. Analysis of the distributions of starting points, time and mean pressure associated with the strokes in sketches revealed that shape defining and shape detailing strokes are separable through thresholding of the stroke parameters. The inter-stroke time plot exhibited characteristic spikes which enabled stroke-sets to be conveniently segmented in to temporal groups. The temporal evolution of shape defining elements and the genesis of feature hierarchy showed significant correlation. This algorithmic stroke organization showed significant match with the segmentation done by designers interactively. Spatial grouping algorithms developed using Gestalt principles isolated shapes in a sketch well. A unified multi-parameter grouping and averaging technique is also presented for obtaining single stroke sketches without losing the feature structure. The work thus demonstrates that algorithmic functional segmentation require both geometric and non-geometric data (viz. coordinates, time-stamp and pressure associated with the strokes) and that the role based classification of strokes helps to relate functional composition of the product and temporal evolution of the sketch. The work identifies how the designers emotion, rational thinking and visualization skill influence the product concept sketching process.
Prevalent discretization methods based on Delaunay Triangulations and Advancing Fronts, which sample and mesh simultaneously, can guarantee well shaped triangles but at a fairly high computational cost. In this paper we present a novel and flexible two-part sampling and meshing algorithm, which produces topologically correct meshes on arbitrary boundary representations whose faces are represented parametrically, without requiring an initial coarse mesh. Our method is based on a hybrid spatial partitioning scheme driven by user-designed subdivision rules that combines the power of quadtree decomposition with the flexibility of the binary decompositions to produce meshes that favor prescribed geometric properties. Importantly, the algorithm offers a performance increase of approximately two orders of magnitude over Delaunay based methods and at least one order of magnitude over advancing front methods. At the same time, our algorithm is practically as fast as the computationally optimal algorithm based on a pure quadtree decomposition, but with a markedly better distribution in the regions with parametric distortion. The hierarchical nature of our surface decomposition is well suited to interactive applications and multithreaded implementation.
