189 research outputs found

    Software Platforms for Smart Cities: Concepts, Requirements, Challenges, and a Unified Reference Architecture

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    Making cities smarter help improve city services and increase citizens' quality of life. Information and communication technologies (ICT) are fundamental for progressing towards smarter city environments. Smart City software platforms potentially support the development and integration of Smart City applications. However, the ICT community must overcome current significant technological and scientific challenges before these platforms can be widely used. This paper surveys the state-of-the-art in software platforms for Smart Cities. We analyzed 23 projects with respect to the most used enabling technologies, as well as functional and non-functional requirements, classifying them into four categories: Cyber-Physical Systems, Internet of Things, Big Data, and Cloud Computing. Based on these results, we derived a reference architecture to guide the development of next-generation software platforms for Smart Cities. Finally, we enumerated the most frequently cited open research challenges, and discussed future opportunities. This survey gives important references for helping application developers, city managers, system operators, end-users, and Smart City researchers to make project, investment, and research decisions.Comment: Accepted for publication in ACM Computing Survey

    Application live-upgrading and error-recovery using code-data decoupling

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    When applications have critical bugs that present security vulnerabilities or may result in serious failures with potential massive business level impact, these applications have to be updated as fast as possible to minimize the harm of the bug. However, mission-critical or other user-facing applications may maintain critical internal state that has to be serialized and restored during the update process introducing signi1cant cost and delay. Instead of serializing the internal state we propose to implement applications in such a way that the application state is fully decoupled (e.g. in a different address space or shared memory segment) from the application logic. Such a decoupling allows for example that upgrades can happen without serialization of the data, even allowing side-by-side execution of the updated and the failing version of the application and thereby reducing application downtime during the update process. Furthermore, this decoupling also allows applications to recover easily from failures by recovering the previous data of the crashed application instance

    SHIELD: Sustainable Hybrid Evolutionary Learning Framework for Carbon, Wastewater, and Energy-Aware Data Center Management

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    Today's cloud data centers are often distributed geographically to provide robust data services. But these geo-distributed data centers (GDDCs) have a significant associated environmental impact due to their increasing carbon emissions and water usage, which needs to be curtailed. Moreover, the energy costs of operating these data centers continue to rise. This paper proposes a novel framework to co-optimize carbon emissions, water footprint, and energy costs of GDDCs, using a hybrid workload management framework called SHIELD that integrates machine learning guided local search with a decomposition-based evolutionary algorithm. Our framework considers geographical factors and time-based differences in power generation/use, costs, and environmental impacts to intelligently manage workload distribution across GDDCs and data center operation. Experimental results show that SHIELD can realize 34.4x speedup and 2.1x improvement in Pareto Hypervolume while reducing the carbon footprint by up to 3.7x, water footprint by up to 1.8x, energy costs by up to 1.3x, and a cumulative improvement across all objectives (carbon, water, cost) of up to 4.8x compared to the state-of-the-art

    MOSAIC: A Multi-Objective Optimization Framework for Sustainable Datacenter Management

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    In recent years, cloud service providers have been building and hosting datacenters across multiple geographical locations to provide robust services. However, the geographical distribution of datacenters introduces growing pressure to both local and global environments, particularly when it comes to water usage and carbon emissions. Unfortunately, efforts to reduce the environmental impact of such datacenters often lead to an increase in the cost of datacenter operations. To co-optimize the energy cost, carbon emissions, and water footprint of datacenter operation from a global perspective, we propose a novel framework for multi-objective sustainable datacenter management (MOSAIC) that integrates adaptive local search with a collaborative decomposition-based evolutionary algorithm to intelligently manage geographical workload distribution and datacenter operations. Our framework sustainably allocates workloads to datacenters while taking into account multiple geography- and time-based factors including renewable energy sources, variable energy costs, power usage efficiency, carbon factors, and water intensity in energy. Our experimental results show that, compared to the best-known prior work frameworks, MOSAIC can achieve 27.45x speedup and 1.53x improvement in Pareto Hypervolume while reducing the carbon footprint by up to 1.33x, water footprint by up to 3.09x, and energy costs by up to 1.40x. In the simultaneous three-objective co-optimization scenario, MOSAIC achieves a cumulative improvement across all objectives (carbon, water, cost) of up to 4.61x compared to the state-of-the-arts

    KYPO: A Tool for Collaborative Study of Cyberattacks in Safe Cloud Environment

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    This paper introduces the KYPO -- a cloud-based virtual environment faithfully simulating real networks and enabling users to study cyber attacks as well as to train users in isolated and controlled environment. Particularly, the paper focuses on the user environment and visualizations, providing views and interactions improving the understanding of processes emerged during experiments. Web user interface of the KYPO system supports several collaboration modes enabling the participants to experiment and replay different types of security related tasks

    Innovation Mashups: Academic Rigor Meets Social Networking Buzz

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    Exploring new options for publishing and content delivery offers an enormous opportunity to improve the state of the art and further modernize academic and professional publications. Traditional organizations such as the IEEE Computer Society, ACM, and Usenix have been encountering increasing competition from new ways of rapid publishing and dissemination, including social networking sites (Facebook, Twitter, LinkedIn, Google+), blogs with enabled commenting, video posting (YouTube), Slashdot, and many other types of media. Liking is replacing traditional impact factors, comments left on authors\u27 webpages or blogs are replacing formal reviews, and site visits have more relevance than the number of article citations

    Heterogeneous Strong Computation Migration

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    The continuous increase in performance requirements, for both scientific computation and industry, motivates the need of a powerful computing infrastructure. The Grid appeared as a solution for inexpensive execution of heavy applications in a parallel and distributed manner. It allows combining resources independently of their physical location and architecture to form a global resource pool available to all grid users. However, grid environments are highly unstable and unpredictable. Adaptability is a crucial issue in this context, in order to guarantee an appropriate quality of service to users. Migration is a technique frequently used for achieving adaptation. The objective of this report is to survey the problem of strong migration in heterogeneous environments like the grids', the related implementation issues and the current solutions.Comment: This is the pre-peer reviewed version of the following article: Milan\'es, A., Rodriguez, N. and Schulze, B. (2008), State of the art in heterogeneous strong migration of computations. Concurrency and Computation: Practice and Experience, 20: 1485-1508, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/cpe.1287/abstrac
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