Recent announcement of the MSN Direct Service has demonstrated the feasibility and industrial interest in utilizing wireless broadcast for pervasive information services. To support location-based services in wireless...
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ISBN:
(纸本)0769523315
Recent announcement of the MSN Direct Service has demonstrated the feasibility and industrial interest in utilizing wireless broadcast for pervasive information services. To support location-based services in wireless data broadcast systems, a distributed spatial index (called DSI) is proposed in this paper DSI is highly efficient because it has a linear yet fully distributed structure that facilitates multiple search paths to be naturally mixed together by sharing links. Moreover DSI is very resilient in error-prone wireless communication environments. Search algorithms for two classical location-based queries, window queries and kNN queries, based on DSI are presented. Performance evaluation of DSI shows that DSI significantly outperforms R-tree and Hilbert Curve Index, two state-of-the-art spatial indexing techniques for wireless data broadcast.
High-quality designs of distributedsystems and services are essential for our digital economy and society. threatening to slow down the stream of working designs, we identify the mounting pressure of scale and comple...
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ISBN:
(纸本)9781728125190
High-quality designs of distributedsystems and services are essential for our digital economy and society. threatening to slow down the stream of working designs, we identify the mounting pressure of scale and complexity of (eco-)systems, of ill-defined and wicked problems, and of unclear processes, methods, and tools. We envision design itself as a core research topic in distributedsystems, to understand and improve the science and practice of distributed (eco-)system design. Toward this vision, we propose the ATLARGE design framework, accompanied by a set of 8 core design principles. We also propose 10 key challenges, which we hope the community can address in the following 5 years. In our experience so far, the proposed framework and principles are practical, and lead to pragmatic and innovative designs for large-scale distributedsystems.
We consider the problem of task assignment in a distributed server system, where short jobs are separated from long jobs, but short jobs may be run in the long job partition if it is idle (cycle stealing). Jobs are as...
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We consider the problem of task assignment in a distributed server system, where short jobs are separated from long jobs, but short jobs may be run in the long job partition if it is idle (cycle stealing). Jobs are assumed to be non-preemptible, where short and long jobs have generally-distributed service requirements, and arrivals are Poisson. We consider two variants of this problem: a central queue model and an immediate dispatch model. this paper presents the first analysis of cycle stealing under the central-queue model. (Cycle stealing under the immediate dispatch model is analyzed in [9]). the analysis uses a technique which we refer to as busy period transitions. Results show that cycle stealing can reduce mean response time for short jobs by orders of magnitude, while long jobs are only slightly penalized. Furthermore using a central queue yields significant performance improvement over immediate dispatch, both from the perspective of the benefit to short jobs and the penalty to long jobs.
Establishing the correctness of reliable distributed protocols supporting critical applications necessitates modular/compositional approaches to tackle the inherent complexity of these protocols. Efforts involved in t...
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ISBN:
(纸本)0769519202
Establishing the correctness of reliable distributed protocols supporting critical applications necessitates modular/compositional approaches to tackle the inherent complexity of these protocols. Efforts involved in the specification and verification of these reliable distributed protocols can be considerably reduced if the protocol is composed utilizing smaller components (building-blocks) possessing individual functionalities that are integral parts of the overall protocol operation. In this paper we present the modular composition of a transaction processing protocol, namely the three-phase commit (3PC) protocol utilizing concepts of category theory. Specifically, we illustrate how the overall global properties of the protocol can be proved by utilizing constructs of local sub-properties of the inherent building blocks of the 3PC protocol.
distributed database systems represent an essential component of modern enterprise application architectures. If the overall application needs to provide reliability and availability, the database has to guarantee the...
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ISBN:
(纸本)9781479954704
distributed database systems represent an essential component of modern enterprise application architectures. If the overall application needs to provide reliability and availability, the database has to guarantee these properties as well. Entailing non-functional database features such as replication, consistency, conflict management, and partitioning represent subsequent challenges for successfully designing and operating an available and reliable database system. In this document, we identify why these concepts are important for databases and classify their design options. Moreover, we survey how eleven modern database systems implement these reliability and availability properties.
In this paper, we investigate the manner in which energy consumption in drone deliveries is affected by windy environmental conditions. We know in fact that the energy consumption of the drone will depend on the stati...
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ISBN:
(纸本)9781665439299
In this paper, we investigate the manner in which energy consumption in drone deliveries is affected by windy environmental conditions. We know in fact that the energy consumption of the drone will depend on the static and dynamic parameters of the scenario where it moves and according to these it decides, during the mission, to detour from the originally planned path to take advantage of the wind changes. In order to validate this, we simulate possible deliveries among fixed destinations relying on a real data-set of recorded winds obtained from different weather stations in Corsica, France. For our analysis, we will mainly concentrate on the evaluation of the delivery scheme proposed in the literature, where completing a delivery means finding a cycle for the drone that is feasible, i.e., that can be completed withthe available energy autonomy of the drone.
We carry out a careful study of Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D) and propose some implementation schemas in the Spark Framework. Focusing on the setting of weight vectors, we prop...
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ISBN:
(纸本)9781538625880
We carry out a careful study of Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D) and propose some implementation schemas in the Spark Framework. Focusing on the setting of weight vectors, we propose two partitioning schemas, which define the distribution mode for the algorithm. the first partitioning schema is to define a partition by a group of weight vectors that are close to each other. the other schema is to distribute close weights to different partitions. Experiments in distributed framework indicate that, for most benchmarks, the schemas in distributed framework can obtain better results and better performance in expansibility.
作者:
Wu, JieTemple Univ
Dept Comp & Informat Sci Ctr Networked Comp Philadelphia PA 19122 USA
Many group activities can be represented as a complex network where entities (vertices) are connected in pairs by lines (edges). Uncovering a useful global structure of complex networks is important for understanding ...
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ISBN:
(纸本)9781538617915
Many group activities can be represented as a complex network where entities (vertices) are connected in pairs by lines (edges). Uncovering a useful global structure of complex networks is important for understanding system behaviors and in providing global guidance 14 application designs. We briefly review existing network models, discuss several tools used in the traditional graph theory, distributedcomputing, distributedsystems, and social network communities, and point out their limitations. We discuss opportunities to uncover the structural properties of complex networks, especially in a mobile environment, and we summarize three promising approaches for uncovering useful structures: trimming, layering, and remapping. Finally, we present some challenges in algorithmic techniques, with a focus on distributed and localized solutions, to represent various structures.
Edgecomputing and Fog computing are new paradigms where data processing is executed in or on the edge of networks to mitigate cloud server load. However, Edgecomputing and Fog computing still need powerful servers on ...
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ISBN:
(纸本)9781509014828
Edgecomputing and Fog computing are new paradigms where data processing is executed in or on the edge of networks to mitigate cloud server load. However, Edgecomputing and Fog computing still need powerful servers on the edge of networks which impose additional costs for deployments. We proposed a platform called IFoT (Information Flow of things) that efficiently performs distributed processing as well as distribution and analysis of data streams near their sources based on "Process On Our Own (PO3)" concept. In IFoT, processing of tasks for cloud servers is delegated to an ad-hoc distributed system consisting of proximity IoT devices for distributed real-time stream processing. In this demonstration, we show a face recognition system for person tracking developed on top of IFoT middleware which locally processes video streams in real-time and in a distributed manner by using computational resources of IoT devices.
Compared withdistributed graph computation, traditionally single node computation is unfitted in processing large scale graph data. the GAS (Gather, Apply and Scatter) Model is a universal vertex-cut graph computatio...
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ISBN:
(纸本)9781538632932
Compared withdistributed graph computation, traditionally single node computation is unfitted in processing large scale graph data. the GAS (Gather, Apply and Scatter) Model is a universal vertex-cut graph computation programming model based on edge-centric programs to support graph algorithms, which process distributed graph computation after graph partition. In this paper, we introduce that three minor-steps of GAS. We then analyze more complete process of GAS considering intra-node computation and inter node communication of distributed graph computation. Based on our analysis, we evaluate the performance in different nodes of graph analysis algorithm applying GAS model. the evaluation shows that the bottleneck is computation performance or communication bandwidth depending on number of nodes, which is an inspiration of optimizing the GAS model.
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