排序方式: 共有75条查询结果,搜索用时 15 毫秒
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In this paper we illustrate how nondeterminism can be used
conveniently and effectively in designing efficient deterministic
algorithms. In particular, our method gives a parameterized
algorithm of running time O((5.7 k)k n) for the 3-D matching
problem, which significantly improves the previous algorithm by
Downey et al. The algorithm can be generalized to
yield an improved algorithm for the r-D matching problem for any
positive integer r. The method can also be employed in designing
deterministic algorithms for other optimization problems as well. 相似文献
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Ahed H. Zyoud Nidal Zaatar Iyad Saadeddin Cheknane Ali DaeHoon Park Guy Campet Hikmat S. Hilal 《Journal of hazardous materials》2010,173(1-3):318-325
Mineralization of phenazopyridine, 1, in water, under solar-simulator radiation was efficiently achieved using nanoparticle CdS-sensitized rutile TiO2, TiO2/CdS, 2, as photo-catalysts. Despite that, 2 showed two main drawbacks. Firstly, the system was difficult to recover by simple filtration, and demanded centrifugation. Secondly, the sensitizer CdS showed relatively high tendency to leach out hazardous Cd2+ ions under photo-degradation reaction conditions. In an attempt to solve out such difficulties, 2 was supported onto sand surface. The sand/TiO2/CdS system, 3, was easier to recover but showed slightly lower catalytic activity compared to 2. On the other hand, the support failed to prevent leaching of Cd2+. This indicates limited future applicability of CdS-sensitized TiO2 photo-catalyst systems, in solar-based water purification strategies, unless leaching out tendency is completely prevented. 相似文献
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Yamen Issa Iyad Dayoub Walaa Hamouda 《Wireless Communications and Mobile Computing》2015,15(8):1225-1233
In this paper, we study the performance of time hopping pulse position modulation for impulse radio ultra‐wideband. We consider relay network applying decode‐and‐forward protocol. The channels between nodes adopt the IEEE 802.15.4a norms. The bit error rate performance is analyzed considering the effect of interference. Our results show significant improvement due to the diversity gain provided by the relay nodes. However, the performance is limited when multiple access interference (MAI) is present. To combat the MAI effect and further improve the detection reliability, we propose to use antenna selection at the relay. The relay receiver is assumed to be equipped with multiple antennas, and only the best antenna is selected. This is shown to improve the performance in the presence of MAI and improve the diversity gain.Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Multimedia Tools and Applications - With the broad development and evolution of digital data exchange, security has become an important issue in data storage and transmission since digital data can... 相似文献
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Doush Iyad Abu Alkhateeb Faisal Gharaibeh Anwaar Hamdi 《International Journal on Document Analysis and Recognition》2018,21(1-2):77-89
International Journal on Document Analysis and Recognition (IJDAR) - Optical character recognition (OCR) is the process of recognizing characters automatically from scanned documents for editing,... 相似文献
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Tight lower bounds for certain parameterized NP-hard problems 总被引:1,自引:0,他引:1
Jianer Chen Benny Chor Mike Fellows Xiuzhen Huang David Juedes Iyad A. Kanj Ge Xia 《Information and Computation》2005,201(2):216-231
Based on the framework of parameterized complexity theory, we derive tight lower bounds on the computational complexity for a number of well-known NP-hard problems. We start by proving a general result, namely that the parameterized weighted satisfiability problem on depth-t circuits cannot be solved in time no(k)mO(1), where n is the circuit input length, m is the circuit size, and k is the parameter, unless the (t − 1)-st level W[t − 1] of the W-hierarchy collapses to FPT. By refining this technique, we prove that a group of parameterized NP-hard problems, including weighted sat, hitting set, set cover, and feature set, cannot be solved in time no(k)mO(1), where n is the size of the universal set from which the k elements are to be selected and m is the instance size, unless the first level W[1] of the W-hierarchy collapses to FPT. We also prove that another group of parameterized problems which includes weighted q-sat (for any fixed q 2), clique, independent set, and dominating set, cannot be solved in time no(k) unless all search problems in the syntactic class SNP, introduced by Papadimitriou and Yannakakis, are solvable in subexponential time. Note that all these parameterized problems have trivial algorithms of running time either nkmO(1) or O(nk). 相似文献
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Iyad Rahwan Dmytro Krasnoshtan Azim Shariff Jean-Fran?ois Bonnefon 《Journal of the Royal Society Interface》2014,11(93)
Social learning—by observing and copying others—is a highly successful cultural mechanism for adaptation, outperforming individual information acquisition and experience. Here, we investigate social learning in the context of the uniquely human capacity for reflective, analytical reasoning. A hallmark of the human mind is its ability to engage analytical reasoning, and suppress false associative intuitions. Through a set of laboratory-based network experiments, we find that social learning fails to propagate this cognitive strategy. When people make false intuitive conclusions and are exposed to the analytic output of their peers, they recognize and adopt this correct output. But they fail to engage analytical reasoning in similar subsequent tasks. Thus, humans exhibit an ‘unreflective copying bias’, which limits their social learning to the output, rather than the process, of their peers’ reasoning—even when doing so requires minimal effort and no technical skill. In contrast to much recent work on observation-based social learning, which emphasizes the propagation of successful behaviour through copying, our findings identify a limit on the power of social networks in situations that require analytical reasoning. 相似文献
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In this paper, we describe a new modeling approach for designing a reliability demonstration test (RDT). The approach, based upon the use of a multiattribute value function, has the advantage of allowing the explicit, and simultaneous, consideration of multiple performance measures (e.g., sample size, consumer's risk, and producer's risk) in the design process. A case study involving the application of the model to the design of the RDTs for a computer assembly plant is also described 相似文献
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Khalid A. Darabkh Wijdan Y. Albtoush Iyad F. Jafar 《The Journal of supercomputing》2017,73(5):1952-1977
In recent years, there has been a growing interest in wireless sensor networks because of their potential usage in a wide variety of applications such as remote environmental monitoring and target tracking. Target tracking is a typical and substantial application of wireless sensor networks. Generally, target tracking aims basically at estimating the location of the target while it is moving within an area of interest and consequently report it to the base station in a timely manner. However, achieving a high accuracy of tracking together with energy efficiency in target tracking algorithms is extremely challenging. In this article, we propose two algorithms to enhance the adaptive-head clustering algorithm, formerly lunched, namely, the improved adaptive-head and improved prediction-based adaptive head. Particularly, the first algorithm uses dynamic clustering to achieve impressive tracking quality and energy efficiency through optimally choosing the cluster head that participates in the tracking process. On the other hand, the second algorithm incorporates a prediction mechanism to the first proposed algorithm. Our proposed algorithms are simulated using Matlab considering various network conditions. Simulation results show that our proposed algorithms can accurately track a target, even when random moving speeds are considered and consume much less energy, when compared with the previous algorithm for target tracking, which in turn prolong the network lifetime much more. 相似文献