245,014 research outputs found

    Unified Bayesian-Experiment Design Regularization Technique for High-Resolution of the Remote Sensing Imagery

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    In this paper, the problem of estimating from a finite set of measurements of the radar remotely sensed complex data signals, the power spatial spectrum pattern (SSP) of the wavefield sources distributed in the environment is cast in the framework of Bayesian minimum risk (MR) paradigm unified with the experiment design (ED) regularization technique. The fused MR-ED regularization of the ill- posed nonlinear inverse problem of the SSP reconstruction is performed via incorporating into the MR estimation strategy the projection-regularization ED constraints. The simulation examples are incorporated to illustrate the efficiency of the proposed unified MR-ED technique.Cinvesta

    Dynamics formulations for the real-time simulation of constrained motion

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    The Space Shuttle program has relied heavily on simulation throughout all phases of development and operation. Real-time, man-in-the-loop simulation has served the NASA manned space flight program by providing the means to evaluate systems design and integrated systems performance in a simulated flight environment as well as provide a means to train flight crews. New challenges are presented by the development and operation of a permanently manned space station. The assembly of the space station, the transferral of payloads and the use of the space station manipulator to berth the Orbiter are operations critical to the success of the space station. All these operations are examples of constrained motion among the bodies associated with the Orbiter and space station system. The state of the art of formulating the governing dynamical equations of motion for constrained systems are described. The uses of the two basic problems in multibody dynamics are discussed. The most efficient formulations of the equations of motion are addressed from the point of view of completeness. The issues surrounding incorporating the constraints into the equation of motion are presented

    Unifying the Experiment Design and Constrained Regularization Paradigms for Reconstructive Imaging with Remote Sensing Data

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    In this paper, the problem of estimating from a finite set of measurements of the radar remotely sensed complex data signals, the power spatial spectrum pattern (SSP) of the wavefield sources distributed in the environment is cast in the framework of Bayesian minimum risk (MR) paradigm unified with the experiment design (ED) regularization technique. The fused MR-ED regularization of the ill-posed nonlinear inverse problem of the SSP reconstruction is performed via incorporating into the MR estimation strategy the projection-regularization ED constraints. The simulation examples are incorporated to illustrate the efficiency of the proposed unified MR-ED technique.CINVESTA

    Integrating computer-aided modeling and micro-simulation in multi-criteria evaluation of service infrastructure assignment approaches

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    Purpose: This paper proposes an integrated computer-supported multi-staged approach to the flexible design and multicriteria evaluation of service infrastructure assignment processes/ algorithms. Design/methodology/approach: It involves particularizing a metamodel encompassing the main generic components and relationships into process models and process instances, by incorporating structural data from the real-life system. Existing data on the target user population is fed into a micro-modeling system to generate a matching population of individual “virtual” users, each with its own set of trait values. The micro-simulation of their interaction with the assignment process of both the incumbent and the competitors generates a rich multi-dimensional output, encompassing both “revealed” and non-observable data. This enables a comprehensive multi-criteria evaluation of the foreseeable performance of the designed process/ algorithm, and therefore its iterative improvement. Findings: The research project developed a set of methodologies and associated supporting tools encompassing the modeling, micro-simulation and performance assessment of service infrastructure assignment processes. Originality/value: The proposed approach facilitates, in a multicriteria environment, the flexible modeling/design of situation-specific assignment processes/algorithms and their performance assessment when facing their case-specific user populationPeer Reviewe

    Collaborative Student Centred Learning: Intellectual Property for Product Designers

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    This paper fits into the topics of student centred learning and learning spaces and explores the question - How will the academic/industrial interface develop? At least a basic understanding of intellectual property (IP) rights is essential for practice as a professional engineer and/or designer to ensure commercial success. Yet it is recognised that there are barriers to incorporating learning and teaching of IP within the Higher Education design and engineering curriculum. These barriers include an already ‘over-packed’ curriculum and no established pedagogy. This paper reports on an example of collaborative student centred learning activity between BA/BSc Product Design (PD) and LLB Law (Intellectual Property Practice option) (LLB) final year students at Bournemouth University (BU). The final year product design students are required to design and produce a working prototype of a marketable product. The LLB students advise on the intellectual property aspects of the design. This learning activity has been ongoing for a number of years, however, last academic year changes were made to incorporate an assessed element for both sets of students and make the learning space almost entirely virtual using the BU virtual learning environment (VLE) called myBU. It is the outcome of these changes that are reported in this paper, using data gathered from the on-line discussion forums and the feedback from students. The activity has proved to be an extremely valuable learning experience for both sets of students, providing simulation of real life for both designers and IP lawyers and bridging the academic/industrial interface

    Multi-Attribute Tradespace Exploration as Front End for Effective Space System Design

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    The inability to approach systematically the high level of ambiguity present in the early design phases of space systems causes long, highly iterative, and costly design cycles. A process is introduced and described to capture decision maker preferences and use them to generate and evaluate a multitude of space system designs, while providing a common metric that can be easily communicated throughout the design enterprise. Communication channeled through formal utility interviews and analysis enables engineers to better understand the key drivers for the system and allows for a more thorough exploration of the design tradespace. Multi-attribute tradespace exploration with concurrent design, a process incorporating decision theory into model- and simulation-based design, has been applied to several space system projects at the Massachusetts Institute of Technology. Preliminary results indicate that this process can improve the quality of communication to resolve more quickly project ambiguity and to enable the engineer to discover better value designs for multiple stakeholders. The process is also integrated into a concurrent design environment to facilitate the transfer of knowledge of important drivers into higher fidelity design phases. Formal utility theory provides a mechanism to bridge the language barrier between experts of different backgrounds and differing needs, for example, scientists, engineers, managers, etc. Multi-attribute tradespace exploration with concurrent design couples decision makers more closely to the design and, most important, maintains their presence between formal reviews

    Modeling human and organizational behavior using a relation-centric multi-agent system design paradigm

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    Today's modeling and simulation communities are being challenged to create rich, detailed models incorporating human decision-making and organizational behavior. Recent advances in distributed artificial intelligence and complex systems theory have demonstrated that such ill-defined problems can be effectively modeled with agent-based simulation techniques using multiple, autonomoous, adaptive entities. RELATE, a relation-centric design paradigm for multi-agent systems (MAS), is presented to assist developers incorporate MAS solutions into their simulations. RELATe focuses the designer on six key concepts of MAS simulations: relationships, environment, laws, agents, things, and effectors. A library of Java classes is presented which enables the user to rapidly prototype an agent-based simulation. This library utilizes the Java programming language to support cross-platform and web based designs. All Java classes and interfaces are fully documented using HTML Javadoc format. Two reference cases are provided that allow for easy code reuse and modification. Finally, an existing metworked DIS-Java-VRML simulation was modified to demonstrate the ability to utilize the RELATE library to add agents to existing applications. LCDR Kim Roddy focused on the development and refinement of the RELATE design paradigm, while LT Mike Dickson focused on the actual Java implementation. Joint work was conducted on all research and reference caseshttp://www.archive.org/details/modelinghumanorg00roddU.S. Navy (U.S.N.) author

    Automated functional coverage driven verification with Universal Verification Methodology

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    Abstract. In this Master’s thesis, the validity of Universal Verification Methodology in digital design verification is studied. A brief look into the methodology’s history is taken, and its unique properties and object-oriented features are presented. Important coverage topics in project planning are discussed, and the two main types of coverage, code and functional coverage, are explained and the methods how they are captured are presented. The practical section of this thesis shows the implementation of a monitoring environment and an Universal Verification Methodology environment. The monitoring environment includes class-based components that are used to collect functional coverage from an existing SystemVerilog test bench. The Universal Verification Methodology environment uses the same monitoring system, but a different driving setup to stress the design under test. Coverage and simulation performance values are extracted and from all test benches and the data is compared. The results indicate that the Universal Verification Methodology environment incorporating constrained random stimulus is capable of faster simulation run times and better code coverage values. The simulation time measured was up to 26 % faster compared to a module-based environment.Automaattinen toiminnallisen kattavuuden ohjaama verifiointi universaalilla varmennusmenetelmĂ€llĂ€. TiivistelmĂ€. TĂ€ssĂ€ diplomityössĂ€ tutkitaan universaalin varmennusmenetelmĂ€n (Universal Verification Methodology) soveltuvuutta digitaalisten laitteiden verifiointiin. TyössĂ€ tehdÀÀn lyhyt katsaus menetelmĂ€n historiaan. LisĂ€ksi menetelmĂ€n omia ainutlaatuisia ja olio-pohjaisia ominaisuuksia kĂ€ydÀÀn lĂ€pi. Kattavuuteen liittyviĂ€ kĂ€sitteitĂ€ esitetÀÀn projektihallinnan nĂ€kökulmasta. Kattavuudesta kĂ€sitellÀÀn toiminnallinen ja koodikattavuus, ja tavat, miten nĂ€itĂ€ molempia kerĂ€tÀÀn simulaatioista. Työn kĂ€ytĂ€nnön osuudessa esitetÀÀn monitorointiympĂ€ristön ja universaalin varmennusmenetelmĂ€n pohjalta tehdyn ympĂ€ristön toteutus. Monitorointi-ympĂ€ristössĂ€ on luokkapohjaisia komponentteja, joiden avulla kerĂ€tÀÀn toiminnallista kattavuutta jo olemassa olevasta testipenkistĂ€. Universaalin varmennusmenetelmĂ€n pohjalta tehdyssĂ€ ympĂ€ristössĂ€ on samojen monitorointikomponenttien lisĂ€ksi testattavan kohteen ohjaamiseen vaadittavia komponentteja. Eri testipenkeistĂ€ kerĂ€tÀÀn kattavuuteen ja suorituskykyyn liittyvÀÀ dataa vertaamista varten. Tulokset viittaavat siihen, ettĂ€ rajoitettua satunnaista herĂ€tettĂ€ hyödykseen kĂ€yttĂ€vĂ€t universaalit varmennusmenetelmĂ€ympĂ€ristöt pÀÀsevĂ€t nopeampiin suoritusaikoihin ja parempiin koodikattavuuslukuihin. Simulaation suoritusaikaan saatiin parhaassa tapauksessa jopa 26 % parannus

    Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

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    A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)

    A survey of current trends in incorporating virtual reality and geographical information systems

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    The paper describes the results of a comprehensive literature and Internet survey on current trends in virtual Reality GIS (VRGIS). In the first part of the paper, a background of VRGIS is set, followed by the description and classification of the main research areas which focus in VRGIS research with an attempt to clarify the reasons that led the researchers to pursue a VR solution for the specific problems in their research field. Based on the observations from the current practice, the main definitions of VRGIS are discussed in the third section. Finally, future directions and possibilities for development are drawn
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