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一种改进的WCA算法 被引量:2
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作者 卢弘 孙学梅 任长明 《计算机工程》 CAS CSCD 北大核心 2006年第11期147-149,共3页
在WCA的基础上,提出了EWCA(Enhanced Weighted Clustering Algorithm)算法,在提高性能的同时降低了开销,并保持了算法的通用性,移动自组网中通过模拟实验对该分簇算法与WCA算法进行了性能比较。
关键词 自组网 分簇算法 统治集 负载平衡 WCA算法
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无线自组网的分簇算法研究
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作者 王海涛 《数字通信世界》 2013年第5期50-53,共4页
分簇算法是构造分级网络结构的关键技术,它的好坏直接影响着无线自组网的性能。本文介绍了无线自组网中分簇算法提出的背景,并阐述了分簇算法的原则和目标,并对无线自组网现存的多种分簇算法进行了详尽的分类介绍和比较分析,包括有簇头... 分簇算法是构造分级网络结构的关键技术,它的好坏直接影响着无线自组网的性能。本文介绍了无线自组网中分簇算法提出的背景,并阐述了分簇算法的原则和目标,并对无线自组网现存的多种分簇算法进行了详尽的分类介绍和比较分析,包括有簇头和无簇头、单跳簇和多跳簇、主动分簇和被动分簇算法等。最后,对簇维护策略进行了简要说明。 展开更多
关键词 无线自组网 分簇算法 服务质量 虚拟骨干网 最小统治集
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Simultaneous integrated boost IMRT in pediatric:evaluation for two commercial treatment planning systems
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作者 Ehab M.Attalla Ismail Eldesoky Eman Eldebawy 《The Chinese-German Journal of Clinical Oncology》 CAS 2013年第1期6-14,共9页
Objective: The aim of the work was to compare the dosimetric results that were obtained by using two treatment planning systems (TPS) Siemens KonRad version 2.2.23, Elekta XiO version 4.4 to perform a simultaneous ... Objective: The aim of the work was to compare the dosimetric results that were obtained by using two treatment planning systems (TPS) Siemens KonRad version 2.2.23, Elekta XiO version 4.4 to perform a simultaneous integrated boost (SIB) for head and neck and central nervous system (CNS) cases in paediatric patients. Methods: The CT scan data for five paediatric patients, with head and neck and CNS tumors, were transferred into both of the TPSs. Clinical step-and-shoot intensity-modulated radiotherapy (IMRT) treatment plans were designed using 6 MV photon beam for delivery on a Siemens Oncor Accelerator with multileaf collimator MLC (82 leaf). Plans were optimized to achieve the same clinical objectives using the same beam energy, number and direction of beams. The analysis was based on isodose distributions, the dose volume histogram (DVH) for planning target volume (PTV) and the relevant organs at risk (OARs) as well as volume receiving 2 Gy and 5 Gy, also total number of segments, MU/segment, and the number of MU/cGy had been investigated. Treatment delivery time and conformation number were two other parameters in this study. Results: The segmentation using KonRad was more efficient, resulting in fewer segments (reduction between 13.2% and 48.3%), fewer M Us (reduction between 10.7% and 33%) and that reflected on treatment delivery times to be shorter by up to 8 rain or 46%. In most of the cases KonRad had the highest volume receiving in excess of 2 and 5 Gy, and XiO showed the lowest. Also KonRad achieved slightly better conformality (0.76 ± 0.054) than XiO (0.73 ± 0.05) while XiO presented a higher modulation factor value (3.3 MU/cGy) than KonRad (2.4 MU/cGy). Conclusion: The KonRad treatment planning system was found to be superior to the XiO treatment planning system. This is true for the possible increase of radiation-induced secondary malignancies as well as for the local control. 展开更多
关键词 intensity-modulated radiotherapy (IMRT) KonRad simultaneous integrated boost (SIB) XiO
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Generating Semi-Algebraic Invariants for Non-Autonomous Polynomial Hybrid Systems 被引量:1
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作者 WANG Qiuye LI Yangjia +1 位作者 XIA Bican ZHAN Naijun 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第1期234-252,共19页
Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, m... Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, many of them are safety-critical, and therefore are required to meet a critical safety standard. Invariant generation plays a central role in the verification and synthesis of hybrid systems. In the previous work, the fourth author and his coauthors gave a necessary and sufficient condition for a semi-algebraic set being an invariant of a polynomial autonomous dynamical system, which gave a confirmative answer to the open problem. In addition, based on which a complete algorithm for generating all semi-algebraic invariants of a given polynomial autonomous hybrid system with the given shape was proposed. This paper considers how to extend their work to non-autonomous dynamical and hybrid systems. Non-autonomous dynamical and hybrid systems are with inputs, which are very common in practice; in contrast, autonomous ones are without inputs. Furthermore, the authors present a sound and complete algorithm to verify semi-algebraic invariants for non-autonomous polynomial hybrid systems. Based on which, the authors propose a sound and complete algorithm to generate all invariants with a pre-defined template. 展开更多
关键词 Hybrid systems INVARIANTS NON-A utonomous systems polynomial ideals semi-algebraic sets.
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