Mobile Crowdsensing leverages the sensing capabilities of multiple mobile devices to execute large-scale sensing tasks by breaking them into smaller tasks for execution on individual mobile devices. Task allocation al...
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ISBN:
(纸本)9781450369046
Mobile Crowdsensing leverages the sensing capabilities of multiple mobile devices to execute large-scale sensing tasks by breaking them into smaller tasks for execution on individual mobile devices. Task allocation algorithms are used to efficiently distribute these smaller sensing tasks to a subset of participants while optimizing system-level goals (such as location accuracy or data quality) for participant selection. The sensing tasks, e.g., collecting GPS tagged data, are often energy-intensive and battery consumption during sensing task execution remains a major concern for participants. So far no in-depth study exists that evaluates the impact of battery consumption on allocation algorithms. In this work, we conducted an in-depth study on the effects of battery consumption patterns of smartphone users. We studied the impact of battery consumption patterns extracted from a real-world data-set on standard as well as state-of-the-art algorithms to show how different battery usage patterns affect the performance of allocation algorithms. Our work provides an important insight into factors affecting the performance of allocation algorithms and advocates incorporating battery usage patterns for the future development of these algorithms.
Phased-array multibeam RF beamformers require calibration of receivers used in an array of elements before the signals can be applied to an analog beamforming network. This article presents a fast O(n(2)) algorithm fo...
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Phased-array multibeam RF beamformers require calibration of receivers used in an array of elements before the signals can be applied to an analog beamforming network. This article presents a fast O(n(2)) algorithm for solving linear systems having a delay Vandermonde matrix (DVM) for the analog beamforming matrix. The structure of the DVM enables to obtain a fast algorithm to efficiently reverse multibeams at the DVM output such that calibration of the input low noise amplifiers can be achieved. The arithmetic complexity of the proposed DVM system solving algorithm is preferable over the standard matrix inversion consuming O(n(3)) operations. Numerical experiments are presented for forward accuracy of the proposed algorithm computed at the calibration frequency. Moreover, numerical results are shown to compare the order of the arithmetic complexity and the execution time of the proposed algorithm. Signal flow graphs are presented for four- and eight-element multibeam phased arrays.
Projection adjustment is a technique that improves the rate of convergence, as measured by the number of iterations needed to achieve a given level of performance, of the Kaczmarz algorithm (KA) for iteratively solvin...
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Projection adjustment is a technique that improves the rate of convergence, as measured by the number of iterations needed to achieve a given level of performance, of the Kaczmarz algorithm (KA) for iteratively solving a system of consistent linear equations, however at the cost of requiring additional time per iteration and increased storage. This hinders the applicability of the previously published Kaczmarz algorithm with projection adjustment (KAPA) to large-scale problems. An enhancement EKAPA of KAPA that uses projection adjustment only for a small subset of the equations is proposed for significantly reducing the time and storage requirements. An analysis of the behavior of EKAPA is provided. An illustration is given to show that EKAPA using a small subset of the equations for projection adjustment can achieve a speed-up over KA similar to that of KAPA in terms of the number of iterations, but requires much less computer time and storage;hence, it is more suitable for large-scale problems.
Satisfiability problems are of importance for many practical problems. They are NP-complete problems. However, some instances of the SAT problem can be solved efficiently. This paper reports on a study concerning the ...
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Satisfiability problems are of importance for many practical problems. They are NP-complete problems. However, some instances of the SAT problem can be solved efficiently. This paper reports on a study concerning the behaviour of a variety of algorithmic approaches to this problem tested on a set of problems collected at FAW. The results obtained give a lot of insight into the algorithms and problems, yet also show some general technical and methodological problems associated with such comparisons.
Concurrent and parallel computing can be used to effectively speed up computations. However, the overall performance gain depends on the way how the concurrency has been introduced to the program. Considering process ...
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ISBN:
(纸本)9783642419478;9783642419461
Concurrent and parallel computing can be used to effectively speed up computations. However, the overall performance gain depends on the way how the concurrency has been introduced to the program. Considering process synchronization as one of the most important aspects in concurrent programming, this paper describes the possibility of application of the model-driven approach in the concept of a software framework for measuring the performance of process synchronization algorithms. Such framework could help determine and analyze the features of specific synchronization techniques in different cases, depending on different input parameters.
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