545,348 research outputs found

    Exploiting lattice structures in shape grammar implementations

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    The ability to work with ambiguity and compute new designs based on both defined and emergent shapes are unique advantages of shape grammars. Realizing these benefits in design practice requires the implementation of general purpose shape grammar interpreters that support: (a) the detection of arbitrary subshapes in arbitrary shapes and (b) the application of shape rules that use these subshapes to create new shapes. The complexity of currently available interpreters results from their combination of shape computation (for subshape detection and the application of rules) with computational geometry (for the geometric operations need to generate new shapes). This paper proposes a shape grammar implementation method for three-dimensional circular arcs represented as rational quadratic Bézier curves based on lattice theory that reduces this complexity by separating steps in a shape computation process from the geometrical operations associated with specific grammars and shapes. The method is demonstrated through application to two well-known shape grammars: Stiny's triangles grammar and Jowers and Earl's trefoil grammar. A prototype computer implementation of an interpreter kernel has been built and its application to both grammars is presented. The use of Bézier curves in three dimensions opens the possibility to extend shape grammar implementations to cover the wider range of applications that are needed before practical implementations for use in real life product design and development processes become feasible

    How to find real-world applications for compressive sensing

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    The potential of compressive sensing (CS) has spurred great interest in the research community and is a fast growing area of research. However, research translating CS theory into practical hardware and demonstrating clear and significant benefits with this hardware over current, conventional imaging techniques has been limited. This article helps researchers to find those niche applications where the CS approach provides substantial gain over conventional approaches by articulating lessons learned in finding one such application; sea skimming missile detection. As a proof of concept, it is demonstrated that a simplified CS missile detection architecture and algorithm provides comparable results to the conventional imaging approach but using a smaller FPA. The primary message is that all of the excitement surrounding CS is necessary and appropriate for encouraging our creativity but we all must also take off our "rose colored glasses" and critically judge our ideas, methods and results relative to conventional imaging approaches.Comment: 10 page

    The SP theory of intelligence: benefits and applications

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    This article describes existing and expected benefits of the "SP theory of intelligence", and some potential applications. The theory aims to simplify and integrate ideas across artificial intelligence, mainstream computing, and human perception and cognition, with information compression as a unifying theme. It combines conceptual simplicity with descriptive and explanatory power across several areas of computing and cognition. In the "SP machine" -- an expression of the SP theory which is currently realized in the form of a computer model -- there is potential for an overall simplification of computing systems, including software. The SP theory promises deeper insights and better solutions in several areas of application including, most notably, unsupervised learning, natural language processing, autonomous robots, computer vision, intelligent databases, software engineering, information compression, medical diagnosis and big data. There is also potential in areas such as the semantic web, bioinformatics, structuring of documents, the detection of computer viruses, data fusion, new kinds of computer, and the development of scientific theories. The theory promises seamless integration of structures and functions within and between different areas of application. The potential value, worldwide, of these benefits and applications is at least $190 billion each year. Further development would be facilitated by the creation of a high-parallel, open-source version of the SP machine, available to researchers everywhere.Comment: arXiv admin note: substantial text overlap with arXiv:1212.022

    Detecting behavioral conflicts among crosscutting concerns

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    Aspects have been successfully promoted as a means to improve the modularization of software in the presence of crosscutting concerns. Within the Ideals project, aspects have been shown to be valuable for improving the modularization of idioms (see also Chapter 1). The so-called aspect interference problem is considered to be one of the remaining challenges of aspect-oriented software development: aspects may interfere with the behavior of the base code or other aspects. Especially interference among aspects is difficult to prevent, as this may be caused solely by the composition of aspects that behave correctly in isolation. A typical situation where this may occur is when multiple advices are applied at the same, or shared, join point. In this chapter we explain the problem of behavioral conflicts among aspects at shared join points, illustrated by aspects that represent idioms: Parameter checking and Error propagation. We present an approach for the detection of behavioral conflicts that is based on a novel abstraction model for representing the behavior of advice. The approach employs a set of conflict detection rules which can be used to detect both generic conflicts as well as domain or application specific conflicts. One of the benefits of the approach is that it neither requires the application programmers to deal with the conflict models, nor does it require a background in formal methods for the aspect programmers

    Challenges of Misbehavior Detection in Industrial Wireless Networks

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    In recent years, wireless technologies are increasingly adopted in many application domains that were either unconnected before or exclusively used cable networks. This paradigm shift towards - often ad-hoc - wireless communication has led to significant benefits in terms of flexibility and mobility. Alongside with these benefits, however, arise new attack vectors, which cannot be mitigated by traditional security measures. Hence, mechanisms that are orthogonal to cryptographic security techniques are necessary in order to detect adversaries. In traditional networks, such mechanisms are subsumed under the term "intrusion detection system" and many proposals have been implemented for different application domains. More recently, the term "misbehavior detection" has been coined to encompass detection mechanisms especially for attacks in wireless networks. In this paper, we use industrial wireless networks as an exemplary application domain to discuss new directions and future challenges in detecting insider attacks. To that end, we review existing work on intrusion detection in mobile ad-hoc networks. We focus on physical-layer-based detection mechanisms as these are a particularly interesting research direction that had not been reasonable before widespread use of wireless technology.Peer Reviewe

    A study of FPGA-based System-on-Chip designs for real-time industrial application

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    This paper shows the benefits of the Field Programming Gate Array (FPGAs) in industrial control applications. The author starts by addressing the benefits of FPGA and where it is useful. As well as, the author has done some FPGA’s evaluation researches on the FPGA performing explaining the performance of the FPGA and the design tools. To show the benefits of the FPGA, an industrial application example has been used. The application is a real-time face detection and tracking using FPGA. Face tracking will depend on calculating the centroid of each detected region. A DE2-SoC Altera board has been used to implement this application. The application based on few algorithms that filter the captured images to detect them. These algorithms have been translated to a Verilog code to run it on the DE2-SoC boar

    Riemann-Langevin Particle Filtering in Track-Before-Detect

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    Track-before-detect (TBD) is a powerful approach that consists in providing the tracker with sensor measurements directly without pre-detection. Due to the measurement model non-linearities, online state estimation in TBD is most commonly solved via particle filtering. Existing particle filters for TBD do not incorporate measurement information in their proposal distribution. The Langevin Monte Carlo (LMC) is a sampling method whose proposal is able to exploit all available knowledge of the posterior (that is, both prior and measurement information). This letter synthesizes recent advances in LMC-based filtering to describe the Riemann-Langevin particle filter and introduces its novel application to TBD. The benefits of our approach are illustrated in a challenging low-noise scenario.Comment: Minor grammatical update
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