3,533 research outputs found

    EOS: A project to investigate the design and construction of real-time distributed embedded operating systems

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    The EOS project is investigating the design and construction of a family of real-time distributed embedded operating systems for reliable, distributed aerospace applications. Using the real-time programming techniques developed in co-operation with NASA in earlier research, the project staff is building a kernel for a multiple processor networked system. The first six months of the grant included a study of scheduling in an object-oriented system, the design philosophy of the kernel, and the architectural overview of the operating system. In this report, the operating system and kernel concepts are described. An environment for the experiments has been built and several of the key concepts of the system have been prototyped. The kernel and operating system is intended to support future experimental studies in multiprocessing, load-balancing, routing, software fault-tolerance, distributed data base design, and real-time processing

    Implementing Session Centered Calculi

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    Recently, specific attention has been devoted to the development of service oriented process calculi. Besides the foundational aspects, it is also interesting to have prototype implementations for them in order to assess usability and to minimize the gap between theory and practice. Typically, these implementations are done in Java taking advantage of its mechanisms supporting network applications. However, most of the recurrent features of service oriented applications are re-implemented from scratch. In this paper we show how to implement a service oriented calculus, CaSPiS (Calculus of Services with Pipelines and Sessions) using the Java framework IMC, where recurrent mechanisms for network applications are already provided. By using the session oriented and pattern matching communication mechanisms provided by IMC, it is relatively simple to implement in Java all CaSPiS abstractions and thus to easily write the implementation in Java of a CaSPiS process

    NASA LARC RAFTOR documentation version 1.0

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    The use of a preprocessor of the LaRC computer center that converts RAFTOR source into FORTRAN source code is described. The purpose of RAFTOR is to make FORTRAN a better programming language for both writing and structuring programs. It is concluded that RAFTOR can generate a well structured program with a source code that is easy to follow

    Macrosystems ecology: Understanding ecological patterns and processes at continental scales

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    Macrosystems ecology is the study of diverse ecological phenomena at the scale of regions to continents and their interactions with phenomena at other scales. This emerging subdiscipline addresses ecological questions and environmental problems at these broad scales. Here, we describe this new field, show how it relates to modern ecological study, and highlight opportunities that stem from taking a macrosystems perspective. We present a hierarchical framework for investigating macrosystems at any level of ecological organization and in relation to broader and finer scales. Building on well-established theory and concepts from other subdisciplines of ecology, we identify feedbacks, linkages among distant regions, and interactions that cross scales of space and time as the most likely sources of unexpected and novel behaviors in macrosystems. We present three examples that highlight the importance of this multiscaled systems perspective for understanding the ecology of regions to continents

    Interactions Between State and Federal Climate Change Policies

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    Federal action addressing climate change is likely to emerge either through new legislation or via the U.S. EPA’s authority under the Clean Air Act. The prospect of federal action raises important questions regarding the interconnections between federal efforts and state-level climate policy developments. In the presence of federal policies, to what extent will state efforts be cost-effective? How does the co-existence of state- and federal-level policies affect the ability of state efforts to achieve emissions reductions? This paper addresses these questions. We find that state-level policy in the presence of a federal policy can be beneficial or problematic, depending on the nature of the overlap between the two systems, the relative stringency of the efforts, and the types of policy instruments engaged. We evaluate a number of arguments that have been made to support state-level climate policy in the presence of federal policies, even when problematic interactions arise.Clean Air Act, climate change, EPA, emissions leakage, federalism, cap-and-trade, carbon tax, regualtion
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