889,928 research outputs found

    Pattern Recognition Control Design

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    Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses

    The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector

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    The development and operation of Liquid-Argon Time-Projection Chambers for neutrino physics has created a need for new approaches to pattern recognition in order to fully exploit the imaging capabilities offered by this technology. Whereas the human brain can excel at identifying features in the recorded events, it is a significant challenge to develop an automated, algorithmic solution. The Pandora Software Development Kit provides functionality to aid the design and implementation of pattern-recognition algorithms. It promotes the use of a multi-algorithm approach to pattern recognition, in which individual algorithms each address a specific task in a particular topology. Many tens of algorithms then carefully build up a picture of the event and, together, provide a robust automated pattern-recognition solution. This paper describes details of the chain of over one hundred Pandora algorithms and tools used to reconstruct cosmic-ray muon and neutrino events in the MicroBooNE detector. Metrics that assess the current pattern-recognition performance are presented for simulated MicroBooNE events, using a selection of final-state event topologies.Comment: Preprint to be submitted to The European Physical Journal

    Design study of a cloud pattern recognition system Final report, 15 Jun. 1964 - 15 Sep. 1965

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    Design technique for cloud pattern recognition applied to Tiros photograph

    Stochastic-Based Pattern Recognition Analysis

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    In this work we review the basic principles of stochastic logic and propose its application to probabilistic-based pattern-recognition analysis. The proposed technique is intrinsically a parallel comparison of input data to various pre-stored categories using Bayesian techniques. We design smart pulse-based stochastic-logic blocks to provide an efficient pattern recognition analysis. The proposed rchitecture is applied to a specific navigation problem. The resulting system is orders of magnitude faster than processor-based solutions

    Purposive Pattern Recognition: The Nature of Visual Choice in Graphic Design

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    Every pamphlet, brochure, booklet, advert, package, poster, etc that has ever been produced involved a visual choice made by a human being - even if the choice were restricted to ‘doing it like the last time’ or ‘copy this one’. Whether graphic designer, information designer, advertising executive, programmer, printer or the Managing Director’s wife, someone decided this picture, this type face, this layout etc rather than some available alternative. How are visual choices made? And, in particular, how do professional graphic designers make choices between visual alternatives. It was decided to probe this question by interviewing professional designers and looking at their work. The initial plan involved some sophisticated analysis of variables but it soon became apparent that such an approach was not possible. Specific interview questions such as, “You decided to use a picture of an elephant. Why an elephant and why this particular one?” met with responses along the lines of, “It just felt right” or “It’s intuitive”. It became clear that although some designers can tell a story about their choices, most designers make use of their experience and the experience of others to arrive at a decision that is not the result of some carefully thought out decision tree or a calculus of competing requirements. It was felt by both of us that there ought to be a better way to describe this process of ‘just knowing its right’ than intuition. Eventually we came up with Purposive Pattern Recognition, abbreviated to PPR. One of us (M A-R) gathered the evidence from interviews, case studies and existing studies of Masters in Design (a title awarded by a US magazine, following a poll of its readership) The other one (J Z L) placed the notion of PPR in a conceptual framework using current thinking in neuroscience and in evolutionary memetics. Keywords: Graphic Design, Intuition, Neuroscience, Memetics.</p

    Pattern Identification - A Foundation for Research in the Emphasis of Design Patterns in Systems Engineering and Knowledge Capture

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    Pattern Language describes the morphology and functionality of a system in the absence of design particulars. Harnessing this capability will provide the Systems Engineering discipline a means of managing the development of increasingly complex systems with increasingly distributed design teams while capturing and retaining knowledge for future generations. Pattern Language is a syntax for describing, and structurally relating, design patterns. Design patterns contextually describe the application of domain knowledge in the engineered solution to the force balance problem. The parallels between pattern recognition and application, as a fundamental stage of human learning, and pattern observation within a complex system, suggests pattern language may be a valuable tool in the capture and dissemination of knowledge. Pattern application has enjoyed considerable study over the last several decades, however much of this work has focused on the replication of design particulars. This work returns to the roots of Pattern Language and explores the utility of patterns as an architectural description and guide, and knowledge capture method, for complex system development beginning with the identification of a time proven design pattern

    Grip-Pattern Recognition for Smart Guns

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    This paper describes the design, implementation and evaluation of a user-verification system for a smart gun, which is based on grip-pattern recognition. An existing pressure sensor consisting of an array of 44 x 44 piezoresistive elements has been used. An interface has been developed to acquire pressure images from the sensor. The values of the pixels in the pressure-pattern images are used as inputs for a verification algorithm, which is currently implemented in software on a computer. The verification algorithm is based on a likelihood-ratio classifier for Gaussian probability densities. First results indicate that it is possible to use grip-pattern recognition for biometric verification, when allowing a certain false-rejection and false-acceptance rate. However, more measurements are needed to give a more reliable indication of the systems performance
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