Information hiding through variance of the parametric orientation underlying a B-rep face

Watermarking technologies have been proposed for many different,types of digital media. However, to this date, no viable watermarking techniques have yet emerged for the high value B-rep (i.e. Boundary Representation) models used in 3D mechanical CAD systems. In this paper, the authors propose a new approach (PO-Watermarking) that subtly changes a model's geometric representation to incorporate a 'transparent' signature. This scheme enables software applications to create fragile, or robust watermarks without changing the size of the file, or shape of the CAD model. Also discussed is the amount of information the proposed method could transparently embed into a B-rep model. The results presented demonstrate the embedding and retrieval of text strings and investigate the robustness of the approach after a variety of transformation and modifications have been carried out on the data

ИНТЕЛЛЕКТУАЛЬНЫЙ числовым программным ДЛЯ MIMD-компьютер

For most scientific and engineering problems simulated on computers the solving of problems of the computational mathematics with approximately given initial data constitutes an intermediate or a final stage. Basic problems of the computational mathematics include the investigating and solving of linear algebraic systems, evaluating of eigenvalues and eigenvectors of matrices, the solving of systems of non-linear equations, numerical integration of initial- value problems for systems of ordinary differential equations.Для більшості наукових та інженерних задач моделювання на ЕОМ рішення задач обчислювальної математики з наближено заданими вихідними даними складає проміжний або остаточний етап. Основні проблеми обчислювальної математики відносяться дослідження і рішення лінійних алгебраїчних систем оцінки власних значень і власних векторів матриць, рішення систем нелінійних рівнянь, чисельного інтегрування початково задач для систем звичайних диференціальних рівнянь.Для большинства научных и инженерных задач моделирования на ЭВМ решение задач вычислительной математики с приближенно заданным исходным данным составляет промежуточный или окончательный этап. Основные проблемы вычислительной математики относятся исследования и решения линейных алгебраических систем оценки собственных значений и собственных векторов матриц, решение систем нелинейных уравнений, численного интегрирования начально задач для систем обыкновенных дифференциальных уравнений

Topology-preserving watermarking of vector graphics

Watermarking techniques for vector graphics dislocate vertices in order to embed imperceptible, yet detectable, statistical features into the input data. The embedding process may result in a change of the topology of the input data, e.g., by introducing self-intersections, which is undesirable or even disastrous for many applications. In this paper we present a watermarking framework for two-dimensional vector graphics that employs conventional watermarking techniques but still provides the guarantee that the topology of the input data is preserved. The geometric part of this framework computes so-called maximum perturbation regions (MPR) of vertices. We propose two efficient algorithms to compute MPRs based on Voronoi diagrams and constrained triangulations. Furthermore, we present two algorithms to conditionally correct the watermarked data in order to increase the watermark embedding capacity and still guarantee topological correctness. While we focus on the watermarking of input formed by straight-line segments, one of our approaches can also be extended to circular arcs. We conclude the paper by demonstrating and analyzing the applicability of our framework in conjunction with two well-known watermarking techniques

Tabu search-based method for bézier curve parameterization

A very important issue in many applied fields is to construct the fitting curve that approximates a given set of data points optimally in the sense of least-squares. This problem arises in a number of areas, such as computer-aided design & manufacturing (CAD/CAM), virtual reality, medical imaging, computer graphics, computer animation, and many others. This is also a hard problem, because it is highly nonlinear, over-determined and typically involves a large number of unknown variables. A critical step in this process is to obtain a suitable parameterization of the data points. In this context, this paper introduces a new method to obtain an optimal solution for the parameterization problem of the least-squares fitting Bézier curve. Our method is based on a local search metaheuristic approach for optimization problems called tabu search. The method is applied to some simple yet illustrative examples for the cases of 2D and 3D curves. The proposed method is simple to understand, easy to implement and can be applied to any kind of smooth data points. Our experimental results show that the presented method performs very well, being able to fit the data points with a high degree of accuracy.This research has been financially supported by the Computer Science National Program of the Spanish Ministry of Economy and Competitiveness, Project Ref. #TIN2012-30768, Toho University, the University of Cantabria, and the Instituto de Física de Cantabria, a mixed research center of the University of Cantabria and CSIC-Consejo Superior de Investigaciones Científicas.Peer Reviewe

Optimal Outsourcing for Intellectual Property Protection and Production Cost Minimization

This paper presents a methodology for optimal outsourcing of products. Outsourcing of products can have the advantage of reducing the production cost, but often causes a risk that important technology may leak and get used by competitors. To help reduce the risk of intellectual property (IP) leakage, a model proposed in this paper assumes that it is possible to separate some of the important geometrical features on some of the product parts that are outsourced, and then manufacture them in-house. The model estimates the fraction of IP-value that is subject to risk of leakage based on patent claims and how they relate to the outsourced parts and/or features. Production cost is modelled by assuming a base cost for manufacturing parts in-house, and then a discount rate is applied if the decision to outsource is made. Separation of geometrical features from manufactured parts introduces additional cost, which is modelled as an overhead if the decision to separate features is made. The outsourcing management process is then viewed as a two-objective problem, with the objectives being the minimization of both the fraction of IP-value at risk of leakage, as well as the production cost. A case study of an auto-slide-hinge mechanism is presented, in which the two-objective optimization problem is transformed into a single-objective constrained problem. Genetic algorithm is then applied iteratively on the problem in order generate the Pareto-plot that visualizes the trade-offs between the two objectives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87272/4/Saitou56.pd

Similarités dans des Modèles BRep Paramétriques : Détection et Applications

Dans cette thèse, nous identifions et exploitons des similarités partielles dans des objets 3D pour répondre à des besoins courants du domaine de la Conception Assistée par Ordinateur (CAO). De nouvelles méthodes sont introduites, d'une part pour détecter les similarités partielles, d'autre part pour utiliser ces similarités dans des applications spécifiques telles que l'édition de forme, la compression et l'indexation d'objets 3D. Grâce au développement des applications de la modélisation géométrique, ces modèles sont de plus en plus nombreux et sont disponibles à travers plusieurs modalités. Pour augmenter la productivité dans la création de tels objets virtuels, la réutilisation et l'adaptation des modèles existants est un choix prioritaire. Cela exige donc des méthodes facilitant le stockage, la recherche et l'exploitation de ces modèles. Heureusement, les similarités dans des objets 3D est un phénomène fréquent. De nombreux objets sont composés de parties similaires à une rotation, à une translation ou à une symétrie près. De ce fait, la détection des similarités partielles dans ces modèles est capable de répondre aux problématiques courantes : la taille du stockage est réduite en conservant seulement une partie au lieu de toutes les parties répétées d'un modèle; l'indexation des modèles 3D requiert a priori l'orientation canonique des modèles. Or, la symétrie dans un objet 3D est toujours une référence d'orientation cohérente avec la perception humaine. Nous utilisons donc la symétrie partielle pour aligner ces modèles et ainsi renforcer la robustesse des méthodes d'indexation. Dans un premier temps, nous introduisons une approche similaire à la Transformée de Hough pour détecter des similarités partielles dans des modèles BRep-NURBS. Cette approche identifie non seulement les parties similaires mais aussi les transformations qui les lient. À travers la classification des isométries dans l'analyse des transformations, notre approche peut distinguer la nature de transformation liant des parties similaires d'un modèle, c'est-à-dire, les parties similaires à une rotation, à une translation ou à une symétrie près. Dans le deuxième temps, nous proposons deux applications héritées directement des résultats obtenus par la détection. Tout d'abord, pour la compression, un modèle se transforme en un graphe de similarités d'où les faces principales à conserver sont sélectionnées dans la structure compressée. Ensuite, pour l'orientation, le plan de la symétrie dominante et la projection orthographique d'un modèle autour de ce plan permettent de définir un repère canonique pour aligner ce modèle. ABSTRACT : In this thesis, we identify and exploit the partial similarities within 3D objects to answer the current needs of the Computer Aided Design field (CAD). Novel methods are introduced, on the one hand to detect the partial similarities, on the other hand to use these similarities for specific applications such as shape editing, compression and indexation of 3D objects. Because of the development of geometric modeling applications, 3D models are getting more numerous and available through many channels. To increase the productivity in creating such 3D virtual objects, the reuse and the adaptation of existing models becomes a prior choice. Thus, it requires methods easing the storage, the searching and the exploitation of these models. Fortunately, similarities within the 3D objects is a popular phenomenon. Many objects are composed of similar patches up to an approximated rotation, translation or symmetry. Hence, detecting the partial similarities within NURBSBRep models is able to solve the current issues : the storage size is reduced by coding a single patch instead of repeated patches of a model ; 3D model indexation requires a canonical orientation of these models. Furthermore, the symmetry within a 3D object is a good orientation reference, coherent with the human perception. Accordingly, we use the partial symmetries to align 3D models and so reinforce the robustness of indexation methods. In a first phase, we introduce an orginal approach similar to the Hough Transform to detect partial similarities within NURBS-BRep models. This approach identifies not only similar patches but also identifies the corresponding transformations that connect them. Additionally, through the classification of isometries in transformations analysis, our approach can distinguish the nature of transformations of similar patches of a model, that is, the patches similar up to an approximated rotation, translation or symmetry. This classification is advantageous for further applications : the similar patches of other transformation natures are considered in compressing ; the symmetric patches are used to normalize 3D models aim at a robust indexation. In the second phase, we propose two applications inherited directly from the obtained results of the detection. Firstly, for the compression, a model is transformed into a similarity graph where the principal faces to be coded are selected to form the compressed structure. Secondly, for the orientation, the plane of the dominant symmetry and the orthographic projection of a model around this plane generate a canonical frame to align this model