1,565 research outputs found

    An exact algorithm for linear optimization problem subject to max-product fuzzy relational inequalities with fuzzy constraints

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    Fuzzy relational inequalities with fuzzy constraints (FRI-FC) are the generalized form of fuzzy relational inequalities (FRI) in which fuzzy inequality replaces ordinary inequality in the constraints. Fuzzy constraints enable us to attain optimal points (called super-optima) that are better solutions than those resulted from the resolution of the similar problems with ordinary inequality constraints. This paper considers the linear objective function optimization with respect to max-product FRI-FC problems. It is proved that there is a set of optimization problems equivalent to the primal problem. Based on the algebraic structure of the primal problem and its equivalent forms, some simplification operations are presented to convert the main problem into a more simplified one. Finally, by some appropriate mathematical manipulations, the main problem is transformed into an optimization model whose constraints are linear. The proposed linearization method not only provides a super-optimum (that is better solution than ordinary feasible optimal solutions) but also finds the best super-optimum for the main problem. The current approach is compared with our previous work and some well-known heuristic algorithms by applying them to random test problems in different sizes.Comment: 29 pages, 8 figures, 7 table

    DCNFIS: Deep Convolutional Neuro-Fuzzy Inference System

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    A key challenge in eXplainable Artificial Intelligence is the well-known tradeoff between the transparency of an algorithm (i.e., how easily a human can directly understand the algorithm, as opposed to receiving a post-hoc explanation), and its accuracy. We report on the design of a new deep network that achieves improved transparency without sacrificing accuracy. We design a deep convolutional neuro-fuzzy inference system (DCNFIS) by hybridizing fuzzy logic and deep learning models and show that DCNFIS performs as accurately as three existing convolutional neural networks on four well-known datasets. We furthermore that DCNFIS outperforms state-of-the-art deep fuzzy systems. We then exploit the transparency of fuzzy logic by deriving explanations, in the form of saliency maps, from the fuzzy rules encoded in DCNFIS. We investigate the properties of these explanations in greater depth using the Fashion-MNIST dataset

    A query processing system for very large spatial databases using a new map algebra

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    Dans cette thĂšse nous introduisons une approche de traitement de requĂȘtes pour des bases de donnĂ©e spatiales. Nous expliquons aussi les concepts principaux que nous avons dĂ©fini et dĂ©veloppĂ©: une algĂšbre spatiale et une approche Ă  base de graphe utilisĂ©e dans l'optimisateur. L'algĂšbre spatiale est dĂ©fini pour exprimer les requĂȘtes et les rĂšgles de transformation pendant les diffĂ©rentes Ă©tapes de l'optimisation de requĂȘtes. Nous avons essayĂ© de dĂ©finir l'algĂšbre la plus complĂšte que possible pour couvrir une grande variĂ©tĂ© d'application. L'opĂ©rateur algĂ©brique reçoit et produit seulement des carte. Les fonctions reçoivent des cartes et produisent des scalaires ou des objets. L'optimisateur reçoit la requĂȘte en expression algĂ©brique et produit un QEP (Query Evaluation Plan) efficace dans deux Ă©tapes: gĂ©nĂ©ration de QEG (Query Evaluation Graph) et gĂ©nĂ©ration de QEP. Dans premiĂšre Ă©tape un graphe (QEG) Ă©quivalent de l'expression algĂ©brique est produit. Les rĂšgles de transformation sont utilisĂ©es pour transformer le graphe a un Ă©quivalent plus efficace. Dans deuxiĂšme Ă©tape un QEP est produit de QEG passĂ© de l'Ă©tape prĂ©cĂ©dente. Le QEP est un ensemble des opĂ©rations primitives consĂ©cutives qui produit les rĂ©sultats finals (la rĂ©ponse finale de la requĂȘte soumise au base de donnĂ©e). Nous avons implĂ©mentĂ© l'optimisateur, un gĂ©nĂ©rateur de requĂȘte spatiale alĂ©atoire, et une base de donnĂ©e simulĂ©e. La base de donnĂ©e spatiale simulĂ©e est un ensemble de fonctions pour simuler des opĂ©rations spatiales primitives. Les requĂȘtes alĂ©atoires sont soumis Ă  l'optimisateur. Les QEPs gĂ©nĂ©rĂ©es sont soumis au simulateur de base de donnĂ©es spatiale. Les rĂ©sultats expĂ©rimentaux sont utilisĂ©s pour discuter les performances et les caractĂ©ristiques de l'optimisateur.Abstract: In this thesis we introduce a query processing approach for spatial databases and explain the main concepts we defined and developed: a spatial algebra and a graph based approach used in the optimizer. The spatial algebra was defined to express queries and transformation rules during different steps of the query optimization. To cover a vast variety of potential applications, we tried to define the algebra as complete as possible. The algebra looks at the spatial data as maps of spatial objects. The algebraic operators act on the maps and result in new maps. Aggregate functions can act on maps and objects and produce objects or basic values (characters, numbers, etc.). The optimizer receives the query in algebraic expression and produces one efficient QEP (Query Evaluation Plan) through two main consecutive blocks: QEG (Query Evaluation Graph) generation and QEP generation. In QEG generation we construct a graph equivalent of the algebraic expression and then apply graph transformation rules to produce one efficient QEG. In QEP generation we receive the efficient QEG and do predicate ordering and approximation and then generate the efficient QEP. The QEP is a set of consecutive phases that must be executed in the specified order. Each phase consist of one or more primitive operations. All primitive operations that are in the same phase can be executed in parallel. We implemented the optimizer, a randomly spatial query generator and a simulated spatial database. The query generator produces random queries for the purpose of testing the optimizer. The simulated spatial database is a set of functions to simulate primitive spatial operations. They return the cost of the corresponding primitive operation according to input parameters. We put randomly generated queries to the optimizer, got the generated QEPs and put them to the spatial database simulator. We used the experimental results to discuss on the optimizer characteristics and performance. The optimizer was designed for databases with a very large number of spatial objects nevertheless most of the concepts we used can be applied to all spatial information systems."--RĂ©sumĂ© abrĂ©gĂ© par UMI

    The 5th Conference of PhD Students in Computer Science

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    Concepts and Techniques for Flexible and Effective Music Data Management

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    EXPLOITING HIGHER ORDER UNCERTAINTY IN IMAGE ANALYSIS

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    Soft computing is a group of methodologies that works synergistically to provide flexible information processing capability for handling real-life ambiguous situations. Its aim is to exploit the tolerance for imprecision, uncertainty, approximate reasoning, and partial truth in order to achieve tractability, robustness, and low-cost solutions. Soft computing methodologies (involving fuzzy sets, neural networks, genetic algorithms, and rough sets) have been successfully employed in various image processing tasks including image segmentation, enhancement and classification, both individually or in combination with other soft computing techniques. The reason of such success has its motivation in the fact that soft computing techniques provide a powerful tools to describe uncertainty, naturally embedded in images, which can be exploited in various image processing tasks. The main contribution of this thesis is to present tools for handling uncertainty by means of a rough-fuzzy framework for exploiting feature level uncertainty. The first contribution is the definition of a general framework based on the hybridization of rough and fuzzy sets, along with a new operator called RF-product, as an effective solution to some problems in image analysis. The second and third contributions are devoted to prove the effectiveness of the proposed framework, by presenting a compression method based on vector quantization and its compression capabilities and an HSV color image segmentation technique

    The 4th Conference of PhD Students in Computer Science

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    Deformable meshes for shape recovery: models and applications

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    With the advance of scanning and imaging technology, more and more 3D objects become available. Among them, deformable objects have gained increasing interests. They include medical instances such as organs, a sequence of objects in motion, and objects of similar shapes where a meaningful correspondence can be established between each other. Thus, it requires tools to store, compare, and retrieve them. Many of these operations depend on successful shape recovery. Shape recovery is the task to retrieve an object from the environment where its geometry is hidden or implicitly known. As a simple and versatile tool, mesh is widely used in computer graphics for modelling and visualization. In particular, deformable meshes are meshes which can take the deformation of deformable objects. They extend the modelling ability of meshes. This dissertation focuses on using deformable meshes to approach the 3D shape recovery problem. Several models are presented to solve the challenges for shape recovery under different circumstances. When the object is hidden in an image, a PDE deformable model is designed to extract its surface shape. The algorithm uses a mesh representation so that it can model any non-smooth surface with an arbitrary precision compared to a parametric model. It is more computational efficient than a level-set approach. When the explicit geometry of the object is known but is hidden in a bank of shapes, we simplify the deformation of the model to a graph matching procedure through a hierarchical surface abstraction approach. The framework is used for shape matching and retrieval. This idea is further extended to retain the explicit geometry during the abstraction. A novel motion abstraction framework for deformable meshes is devised based on clustering of local transformations and is successfully applied to 3D motion compression
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