1,134 research outputs found

    Actors: The Ideal Abstraction for Programming Kernel-Based Concurrency

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    GPU and multicore hardware architectures are commonly used in many different application areas to accelerate problem solutions relative to single CPU architectures. The typical approach to accessing these hardware architectures requires embedding logic into the programming language used to construct the application; the two primary forms of embedding are: calls to API routines to access the concurrent functionality, or pragmas providing concurrency hints to a language compiler such that particular blocks of code are targeted to the concurrent functionality. The former approach is verbose and semantically bankrupt, while the success of the latter approach is restricted to simple, static uses of the functionality. Actor-based applications are constructed from independent, encapsulated actors that interact through strongly-typed channels. This paper presents a first attempt at using actors to program kernels targeted at such concurrent hardware. Besides the glove-like fit of a kernel to the actor abstraction, quantitative code analysis shows that actor-based kernels are always significantly simpler than API-based coding, and generally simpler than pragma-based coding. Additionally, performance measurements show that the overheads of actor-based kernels are commensurate to API-based kernels, and range from equivalent to vastly improved for pragma-based annotations, both for sample and real-world applications

    Middleware Technologies for Cloud of Things - a survey

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    The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

    Middleware Technologies for Cloud of Things - a survey

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    The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

    Specifying and verifying sensor networks: An experiment of formal methods

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    10.1007/978-3-540-88194-0-20Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)5256 LNCS318-33

    Managing large amounts of data generated by a Smart City internet of things deployment

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    The Smart City concept is being developed from a lot of different axes encompassing multiple areas of social and technical sciences. However, something that is common to all these approaches is the central role that the capacity of sharing information has. Hence, Information and Communication Technologies (ICT) are seen as key enablers for the transformation of urban regions into Smart Cities. Two of these technologies, namely Internet of Things and Big Data, have a predominant position among them. The capacity to "sense the city" and access all this information and provide added-value services based on knowledge derived from it are critical to achieving the Smart City vision. This paper reports on the specification and implementation of a software platform enabling the management and exposure of the large amount of information that is continuously generated by the IoT deployment in the city of Santander.This work has been partially funded by the research project SmartSantander, under FP7- ICT-2009-5 of the 7th Framework Programme of the European Community. The authors would also like to express their gratitude to the Spanish government for the funding in the following project: "Connectivity as a Service: Access for the Internet of the Future", COSAIF (TEC2012-38574-C02-01)

    Memory safety and untrusted extensions for TinyOS

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    technical reportSensor network applications should be reliable. However, TinyOS, the dominant sensor net OS, lacks basic building blocks for reliable software systems: memory protection, isolation, and safe termination. These features are typically found in general-purpose operating systems but are believed to be too expensive for tiny embedded systems with a few kilobytes of RAM. We dispel this notion and show that CCured, a safe dialect of C, can be leveraged to provide memory safety for largely unmodified TinyOS applications. We build upon safety to implement two very different environments for TinyOS applications. The first, Safe TinyOS, provides a minimal kernel for safely executing trusted applications. Safe execution traps and identifies bugs that would otherwise have silently corrupted RAM. The second environment, UTOS, implements a user-kernel boundary that supports isolation and safe termination of untrusted code. Existing TinyOS components can often be ported to UTOS with little effort. To create our environments, we substantially augmented the CCured toolchain to emit code that is safe under interrupt-driven concurrency, to reduce storage requirements by compressing error messages, to refactor direct hardware access into calls to trusted helper functions, and to make safe programs more efficient using whole-program optimization. A surprising result of our work is that a safe, optimized TinyOS program can be faster than the original unsafe, unoptimized application

    Memory safety and untrusted extensions for TinyOS

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    Journal ArticleSensor network applications should be reliable. However, TinyOS, the dominant sensor net OS, lacks basic building blocks for reliable software systems: memory protection, isolation, and safe termination. These features are typically found in general-purpose operating systems but are believed to be too expensive for tiny embedded systems with a few kilobytes of RAM. We dispel this notion and show that CCured, a safe dialect of C, can be leveraged to provide memory safety for largely unmodified TinyOS applications. We build upon safety to implement two very different environments for TinyOS applications. The first, Safe TinyOS, provides a minimal kernel for safely executing trusted applications. Safe execution traps and identifies bugs that would otherwise have silently corrupted RAM. The second environment, UTOS, implements a user-kernel boundary that supports isolation and safe termination of untrusted code. Existing TinyOS components can often be ported to UTOS with little effort. To create our environments, we substantially augmented the CCured toolchain to emit code that is safe under interrupt-driven concurrency, to reduce storage requirements by compressing error messages, to refactor direct hardware access into calls to trusted helper functions, and to make safe programs more efficient using whole-program optimization. A surprising result of our work is that a safe, optimized TinyOS program can be faster than the original unsafe, unoptimized application
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