58,406 research outputs found

    RELEASE: A High-level Paradigm for Reliable Large-scale Server Software

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    Erlang is a functional language with a much-emulated model for building reliable distributed systems. This paper outlines the RELEASE project, and describes the progress in the rst six months. The project aim is to scale the Erlang's radical concurrency-oriented programming paradigm to build reliable general-purpose software, such as server-based systems, on massively parallel machines. Currently Erlang has inherently scalable computation and reliability models, but in practice scalability is constrained by aspects of the language and virtual machine. We are working at three levels to address these challenges: evolving the Erlang virtual machine so that it can work effectively on large scale multicore systems; evolving the language to Scalable Distributed (SD) Erlang; developing a scalable Erlang infrastructure to integrate multiple, heterogeneous clusters. We are also developing state of the art tools that allow programmers to understand the behaviour of massively parallel SD Erlang programs. We will demonstrate the e ectiveness of the RELEASE approach using demonstrators and two large case studies on a Blue Gene

    RELEASE: A High-level Paradigm for Reliable Large-scale Server Software

    Get PDF
    Erlang is a functional language with a much-emulated model for building reliable distributed systems. This paper outlines the RELEASE project, and describes the progress in the first six months. The project aim is to scale the Erlang’s radical concurrency-oriented programming paradigm to build reliable general-purpose software, such as server-based systems, on massively parallel machines. Currently Erlang has inherently scalable computation and reliability models, but in practice scalability is constrained by aspects of the language and virtual machine. We are working at three levels to address these challenges: evolving the Erlang virtual machine so that it can work effectively on large scale multicore systems; evolving the language to Scalable Distributed (SD) Erlang; developing a scalable Erlang infrastructure to integrate multiple, heterogeneous clusters. We are also developing state of the art tools that allow programmers to understand the behaviour of massively parallel SD Erlang programs. We will demonstrate the effectiveness of the RELEASE approach using demonstrators and two large case studies on a Blue Gene

    High-Tech Urban Agriculture in Amsterdam : An Actor Network Analysis

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    The agriculture and horticulture sector in the Netherlands is one of the most productive in the world. Although the sector is one of the most advanced and intense agricultural production systems worldwide, it faces challenges, such as climate change and environmental and social unsustainability of industrial production. To overcome these challenges, alternative food production initiatives have emerged, especially in large cities such as Amsterdam. Some initiatives involve producing food in the urban environment, supported by new technologies and practices, so-called high-tech urban agriculture (HTUA). These initiatives make cultivation of plants inside and on top of buildings possible and increase green spaces in urban areas. The emerging agricultural technologies are creating new business environments that are shape d by technology developers (e.g., suppliers of horticultural light emitting diodes (LED) and control environment systems) and developers of alternative food production practices (e.g., HTUA start-ups). However, research shows that the uptake of these technological innovations in urban planning processes is problematic. Therefore, this research analyzes the barriers that local government planners and HTUA developers are facing in the embedding of HTUA in urban planning processes, using the city of Amsterdam as a case study. This study draws on actor-network theory (ANT) to analyze the interactions between planners, technologies, technology developers and developers of alternative food production practices. Several concepts of ANT are integrated into a multi-level perspective on sustainability transitions (MLP) to create a new theoretical framework that can explain how interactions between technologies and planning actors transform the incumbent social\u2013technical regime. The configuration of interactions between social and material entities in technology development and adoption processes in Amsterdam is analyzed through the lens of this theoretical framework. The data in this study were gathered by tracing actors and their connections by using ethnographic research methods. In the course of the integration of new technologies into urban planning practices, gaps between technologies, technology developers, and planning actors have been identified. The results of this study show a lacking connection between planning actors and technology developers, although planning actors do interact with developers of alternative food production practices. These interactions are influenced by agency of artefacts such as visualizations of the future projects. The paper concludes that for the utilization of emerging technologies for sustainability transition of cities, the existing gap between technology developers and planning actors needs to be bridged through the integration of technology development visions in urban agendas and planning processe

    Exploiting Cognitive Structure for Adaptive Learning

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    Adaptive learning, also known as adaptive teaching, relies on learning path recommendation, which sequentially recommends personalized learning items (e.g., lectures, exercises) to satisfy the unique needs of each learner. Although it is well known that modeling the cognitive structure including knowledge level of learners and knowledge structure (e.g., the prerequisite relations) of learning items is important for learning path recommendation, existing methods for adaptive learning often separately focus on either knowledge levels of learners or knowledge structure of learning items. To fully exploit the multifaceted cognitive structure for learning path recommendation, we propose a Cognitive Structure Enhanced framework for Adaptive Learning, named CSEAL. By viewing path recommendation as a Markov Decision Process and applying an actor-critic algorithm, CSEAL can sequentially identify the right learning items to different learners. Specifically, we first utilize a recurrent neural network to trace the evolving knowledge levels of learners at each learning step. Then, we design a navigation algorithm on the knowledge structure to ensure the logicality of learning paths, which reduces the search space in the decision process. Finally, the actor-critic algorithm is used to determine what to learn next and whose parameters are dynamically updated along the learning path. Extensive experiments on real-world data demonstrate the effectiveness and robustness of CSEAL.Comment: Accepted by KDD 2019 Research Track. In Proceedings of the 25th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining (KDD'19

    Using mixed methods to track the growth of the Web: tracing open government data initiatives

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    In recent years, there have been a rising number of Open Government Data (OGD) initiatives; a political, social and technical movement armed with a common goal of publishing government data in open, re-usable formats in order to improve citizen-to-government transparency, efficiency, and democracy. As a sign of commitment, the Open Government Partnership was formed, comprising of a collection of countries striving to achieve OGD. Since its initial launch, the number of countries committed to adopting an Open Government Data agenda has grown to more than 50; including countries from South America to the Far East.Current approaches to understanding Web initiatives such as OGD are still being developed. Methodologies grounded in multidisciplinarity are still yet to be achieved; typically research follows a social or technological approach underpinned by quantitative or qualitative methods, and rarely combining the two into a single analytical framework. In this paper, a mixed methods approach will be introduced, which uses qualitative data underpinned by sociological theory to complement a quantitative analysis using computer science techniques. This method aims to provide an alternative approach to understanding the socio-technical activities of the Web. To demonstrate this, the activities of the UK Open Government Data initiative will be explored using a range of quantitative and qualitative data, examining the activities of the community, to provide a rich analysis of the formation and development of the UK OGD community

    Architecture for Provenance Systems

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    This document covers the logical and process architectures of provenance systems. The logical architecture identifies key roles and their interactions, whereas the process architecture discusses distribution and security. A fundamental aspect of our presentation is its technology-independent nature, which makes it reusable: the principles that are exposed in this document may be applied to different technologies

    Strenthening local food systems: tracing learning of knowledge and skills by content and discourse analysis

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    The local food systems meet the food systems of scale on the local market, where the local and regional chains are looking for ways to survive and even to strengthen. The operations of local food systems become decided by many actors embedded in a socially complex local environment. This paper discusses some approaches to learning in the food chains and some qualitative research methods to capture learning in the chains through empirical material. The main research question, the learning of the actors in the local food chain and the effects of learning on the activities of the local chain are opened as more detailed and operative questions

    An Architecture for Provenance Systems

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    This document covers the logical and process architectures of provenance systems. The logical architecture identifies key roles and their interactions, whereas the process architecture discusses distribution and security. A fundamental aspect of our presentation is its technology-independent nature, which makes it reusable: the principles that are exposed in this document may be applied to different technologies

    On Synchronous and Asynchronous Monitor Instrumentation for Actor-based systems

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    We study the impact of synchronous and asynchronous monitoring instrumentation on runtime overheads in the context of a runtime verification framework for actor-based systems. We show that, in such a context, asynchronous monitoring incurs substantially lower overhead costs. We also show how, for certain properties that require synchronous monitoring, a hybrid approach can be used that ensures timely violation detections for the important events while, at the same time, incurring lower overhead costs that are closer to those of an asynchronous instrumentation.Comment: In Proceedings FOCLASA 2014, arXiv:1502.0315

    Actor-relational planning in deprived areas : challenges and opportunities in luchtbal Antwerpen, Belgium

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    In this article we report and discuss our experience with actor relational approaches in the regeneration of a post war housing estate in Luchtbal, Antwerp, Belgium. Actor relational approaches are informed by post-structuralist ideas of space, complexity theory and actor network theory. Although ARA itself is not new, the application of ARA to deprived area’s such as Luchtbal is novel. We report how the approach has been elaborated, its process and outcome. We conclude with our evaluation from an insider’s perspective
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