391,238 research outputs found

    Advanced propulsion system for hybrid vehicles

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    A number of hybrid propulsion systems were evaluated for application in several different vehicle sizes. A conceptual design was prepared for the most promising configuration. Various system configurations were parametrically evaluated and compared, design tradeoffs performed, and a conceptual design produced. Fifteen vehicle/propulsion systems concepts were parametrically evaluated to select two systems and one vehicle for detailed design tradeoff studies. A single hybrid propulsion system concept and vehicle (five passenger family sedan)were selected for optimization based on the results of the tradeoff studies. The final propulsion system consists of a 65 kW spark-ignition heat engine, a mechanical continuously variable traction transmission, a 20 kW permanent magnet axial-gap traction motor, a variable frequency inverter, a 386 kg lead-acid improved state-of-the-art battery, and a transaxle. The system was configured with a parallel power path between the heat engine and battery. It has two automatic operational modes: electric mode and heat engine mode. Power is always shared between the heat engine and battery during acceleration periods. In both modes, regenerative braking energy is absorbed by the battery

    Design Spaces for Sociotechnical Systems

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    This conceptual paper is a step toward bridging the gap between thinking of systems as tools that are used and thinking of systems as sociotechnical systems with human participants. Its description of design spaces for sociotechnical systems applies a work system perspective. Its theory of sociotechnical design encompasses planned and unplanned change in those work systems. Its overall approach supports analysis and design at various levels of depth without implicitly biasing the result toward non-technical or technical aspects of the situation. The work system approach to sociotechnical design provides a path for going far beyond simple relationships between function and form. This paper summarizes aspects of that path, including: • Framework for summarizing work systems within organizations; • A theory of sociotechnical design; • Decomposition of work systems into subsystems and their interactions; • Parallel application of multiple design spaces organized around work system elements. The paper concludes by listing advantages of its approach to sociotechnical design

    Revisiting Actor Programming in C++

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    The actor model of computation has gained significant popularity over the last decade. Its high level of abstraction makes it appealing for concurrent applications in parallel and distributed systems. However, designing a real-world actor framework that subsumes full scalability, strong reliability, and high resource efficiency requires many conceptual and algorithmic additives to the original model. In this paper, we report on designing and building CAF, the "C++ Actor Framework". CAF targets at providing a concurrent and distributed native environment for scaling up to very large, high-performance applications, and equally well down to small constrained systems. We present the key specifications and design concepts---in particular a message-transparent architecture, type-safe message interfaces, and pattern matching facilities---that make native actors a viable approach for many robust, elastic, and highly distributed developments. We demonstrate the feasibility of CAF in three scenarios: first for elastic, upscaling environments, second for including heterogeneous hardware like GPGPUs, and third for distributed runtime systems. Extensive performance evaluations indicate ideal runtime behaviour for up to 64 cores at very low memory footprint, or in the presence of GPUs. In these tests, CAF continuously outperforms the competing actor environments Erlang, Charm++, SalsaLite, Scala, ActorFoundry, and even the OpenMPI.Comment: 33 page

    Model for an Intelligent Operating System for Executing Tasks on a Reconfigurable Parallel Architecture

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    Parallel processing is one approach to achieve the large computational processing capabilities required by many real-time computing tasks. One of the problems that must be addressed in the use of reconfigurable multiprocessor systems is matching the architecture configuration to the algorithms to be executed. This paper presents a conceptual model that explores the potential of artificial intelligence tools, specifically expert systems, to design an Intelligent Operating System for multiprocessor systems. The target task is the implementation of image understanding systems on multiprocessor architectures. PASM is used as an example multiprocessor. The Intelligent Operating System concepts developed here could also be used to address other problems requiring real-time processing. An example image understanding task is presented to illustrate the concept of intelligent scheduling by the Intelligent Operating System. Also considered is the use of the conceptual model when developing an image understanding system in order to test different strategies for choosing algorithms, imposing execution order constraints, and integrating results from various algorithms

    Integration of an increasing-fidelity aerodynamic modelling approach in the conceptual design of hypersonic cruiser

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    This paper deals with the integration of an increasing-fidelity aerodynamic modelling approach in the conceptual design of hypersonic cruiser. At this purpose, a dedicated methodology has been developed in the framework of the H2020 STRATOFLY project and applied to the STRATOFLY MR3, the Mach 8 waverider reference configuration. Considering the complexity of the concept to be analyzed at conceptual/preliminary design stage, a build-up approach has been adopted, incrementally increasing the complexity of the aerodynamic model, from the clean external configuration up to the complete configuration, including Propulsion Systems Elements and Flight Control Surfaces. In parallel to the aerodynamic analysis, detailed Mission Analyses are performed at each step, benefitting of the incremental versions of the Aerodynamic Database which are used as input. The application of the entire methodology to the reference case-study, allows to estimate design margins to be used at the different steps, to avoid unsolicited under/over-estimations of fuel mass and ranges

    OpTiX-II: A Software Environment for MCDM based on Distributed and Parallel Computing

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    The intention of the paper is to give an introduction to the OpTiX-II Software Environment, which supports the parallel and distributed solution of decision problems which can be represented as mathematical nonlinear programming tasks. First, a brief summary of nonsequential solution concepts for this class of decision problems on multiprocessor systems will be given. The focus of attention will be put on coarse-grained parallelization and its implementation on multi-computer clusters. The conceptual design objectives for the OpTiX-II Software Environment will be presented as well as the implementation on a workstation cluster, a transputer system and a multiprocessor workstation (shared memory). The OpTiX-II system supports the steps from the formulation of decision problems to their solution on networks of (parallel) computers. In order to demonstrate the use of OpTiX-II, the solution of a decision problem from the field of structural design is discussed and some numerical test results are supplied

    Adaptive structured parallelism

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    Algorithmic skeletons abstract commonly-used patterns of parallel computation, communication, and interaction. Parallel programs are expressed by interweaving parameterised skeletons analogously to the way in which structured sequential programs are developed, using well-defined constructs. Skeletons provide top-down design composition and control inheritance throughout the program structure. Based on the algorithmic skeleton concept, structured parallelism provides a high-level parallel programming technique which allows the conceptual description of parallel programs whilst fostering platform independence and algorithm abstraction. By decoupling the algorithm specification from machine-dependent structural considerations, structured parallelism allows programmers to code programs regardless of how the computation and communications will be executed in the system platform.Meanwhile, large non-dedicated multiprocessing systems have long posed a challenge to known distributed systems programming techniques as a result of the inherent heterogeneity and dynamism of their resources. Scant research has been devoted to the use of structural information provided by skeletons in adaptively improving program performance, based on resource utilisation. This thesis presents a methodology to improve skeletal parallel programming in heterogeneous distributed systems by introducing adaptivity through resource awareness. As we hypothesise that a skeletal program should be able to adapt to the dynamic resource conditions over time using its structural forecasting information, we have developed ASPara: Adaptive Structured Parallelism. ASPara is a generic methodology to incorporate structural information at compilation into a parallel program, which will help it to adapt at execution

    A new paradigm for deep sustainability: biourbanism

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    Biourbanism introduces new conceptual and planning models for a new kind of city, valuing social and economical regeneration of the built environment through developing and healthy communities. Thus, it combines technical aspects, such as zero-emission, energy efficiency, information technology, etc. and the promotion of social sustainability and human well being. In effect, this new paradigm endorses principles of geometrical coherence, Biophilic design, BioArchitecture, Biomimesis, etc. in practices of design and also new urban policies and, especially Biopolitics to promote urban revitalization by ensuring that man-made changes do not have harmful effects to humans. Green city standards start inside the designs of each building and continue either in unbuilt spaces surrounding buildings or inside complex infrastructural networks, connecting buildings and people. The proposed presentation should illustrate how new exciting developments recently, such as fractals, complexity theory, evolutionary biology and artificial intelligence are interrelated and constantly stimulate interaction between human beings and the surrounding environment. New Biophilic solutions in designs of buildings have been proved as attractive opportunities for new markets of housing. Thus, some new infrastructural projects start embracing Biophilic advanced solutions which finally aim at energy efficiency and optimal performance. As parallel activity we can now see emerging new innovative monitoring systems of building health not only in small scale, but also in large scale buildings, such as rail stations, for example, and commercial centres or even sometimes entire educational complexes integrated to new infrastructural projects. Some important case studies are going to be presented; they have been analysed and evaluated by Biourbanism and Biophilia principles and applied methods of design

    Distributed intelligence for supervisory control

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    Supervisory control systems must deal with various types of intelligence distributed throughout the layers of control. Typical layers are real-time servo control, off-line planning and reasoning subsystems and finally, the human operator. Design methodologies must account for the fact that the majority of the intelligence will reside with the human operator. Hierarchical decompositions and feedback loops as conceptual building blocks that provide a common ground for man-machine interaction are discussed. Examples of types of parallelism and parallel implementation on several classes of computer architecture are also discussed
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