As the use of computer simulation is increasingly becoming central to scientific enterprise, lack of proper documentation, validation and distribution of models and experiments may hamper reproducibility and hence cau...
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Social-web giants - like ***, ***, and *** - are quickly becoming the driving force behind content generation on the web. Because these sites have incredibly large user-bases and content is frequently cross-posted bet...
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Traditionally, members of communities of practice collaborated through traditional means: word of mouth, conferences, lectures and hand written notes. However, the emergence of online environments, have led to the use...
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Solid-state disks (SSDs) with high I/O performance are increasingly becoming popular. To extend the life time of flash memory, one can apply wear-leveling strategies to manage data blocks. However, wearleveling strate...
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Solid-state disks (SSDs) with high I/O performance are increasingly becoming popular. To extend the life time of flash memory, one can apply wear-leveling strategies to manage data blocks. However, wear-leveling strat...
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Solid-state disks (SSDs) with high I/O performance are increasingly becoming popular. To extend the life time of flash memory, one can apply wear-leveling strategies to manage data blocks. However, wear-leveling strategies certainly inevitably degrade write performance. In addition to low write performance, wear-leveling strategies make one block unwritable when one bit of this block is invalid. Although data reconstruction techniques have been widely employed in disk arrays, the reconstruction techniques has not been studied in the context of solid-state disks. In this paper, we present a new fine-grained data-reconstruction algorithm for solid-state disks. The algorithm aims to provide a simple yet efficient wear-leveling strategy that improves both I/O performance and reliability of solid-state disks. Simulation experiments show that all data blocks have very similar in terms of erasure times. The number of extra erasures incurred by our algorithm is very marginal.
The performance of IEEE 802.11 in multi-hop wireless networks depends on the characteristics of the protocol itself, and on those of the upper layer routing protocol. Extensive work has been done to analyze and evalua...
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The performance of IEEE 802.11 in multi-hop wireless networks depends on the characteristics of the protocol itself, and on those of the upper layer routing protocol. Extensive work has been done to analyze and evaluate the performance of single hop networks under saturated traffic conditions, either through simulations or mathematical modeling. Little work has been done on the analysis of the performance of IEEE 802.11 protocol under the unsaturated traffic conditions that arise in multi-hop networks. The paper proposes analytical models and scenarios for such an analysis. ns-2 simulations with different network configurations validate the proposed models for performance metrics such as throughput, message delay, average queue length, and energy consumption. Simulation results show that the proposed models work well. Key to the modeling of the multi-hop networks is a treatment of the upper layer routing protocols that can affect the network performance through the way they forward packets and the impact of that on the traffic load. The model proposed takes into account the impact of the upper layer routing protocol by introducing a packet acceptance factor with which each relay station accepts packets from the wireless medium before forwarding the same.
Many curricular guidelines, such as the Recommended Curriculum for computerscience at Liberal Arts colleges [4], suggest that students be exposed to many different programming paradigms (e.g., imperative, functional,...
ISBN:
(纸本)9781581133295
Many curricular guidelines, such as the Recommended Curriculum for computerscience at Liberal Arts colleges [4], suggest that students be exposed to many different programming paradigms (e.g., imperative, functional, object-oriented, declarative) in the undergraduate curriculum. Some institutions believe that students should have early exposure to many paradigms, often as early as the first two *** institutions emphasize object-oriented programming early in the curriculum. Some also include functional programming. Imperative topics are often covered in courses that emphasize object-oriented or functional issues. Where does declarative programming fit? Sometimes not until an upper-level language paradigms course or artificial intelligence course. Sometimes it never fits, at least not explicitly.
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