In this paper, the Linear Parameter Varying (LPV) model identification framework is applied to estimating time-varying human controller (HC) dynamics in a single-loop tracking task. Given the inherently unknown time c...
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The IEEE802.15.4e standard for low power wireless sensor networks defines a new mode called Time Slotted Channel Hopping (TSCH) as Medium Access Control (MAC). TSCH allows highly efficient deterministic time-frequency...
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ISBN:
(纸本)9781538638392
The IEEE802.15.4e standard for low power wireless sensor networks defines a new mode called Time Slotted Channel Hopping (TSCH) as Medium Access Control (MAC). TSCH allows highly efficient deterministic time-frequency schedules that are built and maintained by the 6TiSCH operation sublayer (6top). In this paper, we propose a solution to limit the allocation of identical cells to co-located pair of nodes by distributed TSCH scheduling algorithms. It consists of making nodes able to overhear past cell negotiations exchanged in shared cells by their neighbors and prevent the nodes from reusing already assigned cells in future allocations. Our mechanism has been tested through simulations that show a significant improvement with respect to random scheduling algorithms.
The quality of a Web search engine is influenced by several factors, including coverage and the freshness of the content gathered by the web crawler. Focusing particularly on freshness, one key challenge is to estimat...
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The quality of a Web search engine is influenced by several factors, including coverage and the freshness of the content gathered by the web crawler. Focusing particularly on freshness, one key challenge is to estimate the likelihood of a previously crawled webpage being modified. Such estimates are used to define the order in which those pages should be visited, and thus, can be exploited to reduce the cost of monitoring crawled webpages for keeping updated versions. We here present a Genetic Programming framework, called -Genetic Programming for Crawling, to generate score functions that produce accurate rankings of pages regarding their probabilities of having been modified. We compare with state-of-the-art methods using a large dataset of webpages crawled from the Brazilian Web. Our evaluation includes multiple performance metrics and several variations of our framework, built from exploring different sets of terminals and fitness functions. In particular, we evaluate using the ChangeRate and Normalized Discounted Cumulative Gain (NDCG) metrics as both objective function and evaluation metric. We show that, in comparison with ChangeRate, NDCG has the ability of better evaluating the effectiveness of scheduling strategies, since it is able to take the ranking produced by the scheduling into account.
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