A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard...A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard, in the strong sense, or open problems, therefore approximation algorithms are studied. The review reveals that there exist some potential areas worthy of further research.展开更多
The traditional HB-weighted time-delay estimation （TDE） method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics （FLOS...The traditional HB-weighted time-delay estimation （TDE） method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics （FLOS） according to the impulsive characteristics of fractional lower order α-stable noises. Theoretic analysis and computer simulations indicate that the proposed covariation based HB weighted （COV-HB） algorithm can suppress impulsive noises in one received signal for 1 ≤α≤ 2, whereas the other proposed fractional lower order eovariancebased HB weighted （FLOC-HB） algorithm has robust performance under arbitrary impulsive noise conditions for the whole range of 0 〈α≤ 2.展开更多
This paper studies the weighted average consensus problem for networks of agents with fixed directed asymmetric unbalance information exchange topology. We suppose that the classical distributed consensus protocol is ...This paper studies the weighted average consensus problem for networks of agents with fixed directed asymmetric unbalance information exchange topology. We suppose that the classical distributed consensus protocol is destroyed by diverse time-delays which include communication time-delay and self time-delay. Based on the generalized Nyquist stability criterion and the Gerschgorin disk theorem, some sufficient conditions for the consensus of multi-agent systems are obtained. And we give the expression of the weighted average consensus value for our consensus protocol. Finally, numerical examples are presented to illustrate the theoretical results.展开更多
This paper takes the evaluation of overall economic benefit by an example and proposes a simple additive weighting method for time-series multiindices decision making. The method can automatically determine the weight...This paper takes the evaluation of overall economic benefit by an example and proposes a simple additive weighting method for time-series multiindices decision making. The method can automatically determine the weight coefficients among the multiindices and the years respectively and it also can obtain the objective evaluation results and conclusions.展开更多
基金the National Natural Science Foundation of China (70631003)the Hefei University of Technology Foundation (071102F).
文摘A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard, in the strong sense, or open problems, therefore approximation algorithms are studied. The review reveals that there exist some potential areas worthy of further research.
基金supported by the National Natural Science Foundation of China (60372081)China Postdoctoral Science Foundation (20070410347)the Doctor Startup Fund of Liaoning Province (20071076)
文摘The traditional HB-weighted time-delay estimation （TDE） method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics （FLOS） according to the impulsive characteristics of fractional lower order α-stable noises. Theoretic analysis and computer simulations indicate that the proposed covariation based HB weighted （COV-HB） algorithm can suppress impulsive noises in one received signal for 1 ≤α≤ 2, whereas the other proposed fractional lower order eovariancebased HB weighted （FLOC-HB） algorithm has robust performance under arbitrary impulsive noise conditions for the whole range of 0 〈α≤ 2.
基金supported by the National Natural Science Foundation of China(6127312661363002+3 种基金61374104)the Natural Science Foundation of Guangdong Province(10251064101000008S2012010009675)the Fundamental Research Funds for the Central Universities(2012ZM0059)
文摘This paper studies the weighted average consensus problem for networks of agents with fixed directed asymmetric unbalance information exchange topology. We suppose that the classical distributed consensus protocol is destroyed by diverse time-delays which include communication time-delay and self time-delay. Based on the generalized Nyquist stability criterion and the Gerschgorin disk theorem, some sufficient conditions for the consensus of multi-agent systems are obtained. And we give the expression of the weighted average consensus value for our consensus protocol. Finally, numerical examples are presented to illustrate the theoretical results.
文摘This paper takes the evaluation of overall economic benefit by an example and proposes a simple additive weighting method for time-series multiindices decision making. The method can automatically determine the weight coefficients among the multiindices and the years respectively and it also can obtain the objective evaluation results and conclusions.
文摘草地地上生物量(Aboveground Biomass,AGB)是衡量草地生态系统功能和质量的核心指标。然而,在呼伦贝尔草原长时序、大尺度的AGB反演中,由于部分年份样本点稀少甚至缺失,年际反演模型的精度难以保证,影响了对草原生态系统动态变化的准确评估。为解决这一关键问题,本文提出了一种基于精度分配权重的年际优化反演模型,旨在提高AGB反演精度,并通过模型结果分析呼伦贝尔草地AGB的时空变化特征。首先,以2003年、2004年、2009年和2010年的Landsat-5的Level-2数据为数据源,计算得到植被指数;以遥感影像时间为基准提取气象数据,结合野外样地实测草地AGB数据进行相关性分析,提取相关性最高的植被指数、气温和降水数据,利用偏最小二乘(Partial Least Squares Regression,PLSR)算法构建得出三年的草地AGB反演模型;然后对三年草地AGB反演模型采用简单平均法、加权平均线性法和精度分配权重法进行评估,结果表明精度分配权重模型为最优模型;再利用实测AGB对最优模型进行对比分析评估模型精度;最后,利用得到的最优模型对呼伦贝尔草地AGB进行长时序生物量反演并分析草地AGB时空变化特征。结果表明:(1)植被指数NDPI、气温和降水数据与草地AGB之间的相关性较高,分别为0.67、0.26和0.29;(2)三种模型中,精度分配权重回归模型拟合效果最好(R2为0.67),对比分析的精度也优于其余两种模型;(3)草地AGB空间分布呈现由西向东逐渐增多的趋势,且该趋势在大多数年份中保持一致,尤其在1996年、2013年和2018年表现最为明显。然而,在1997年和2007年,该趋势的变化幅度较小或出现一定的波动,表现出不同的空间分布特征;时间分布上,除了1997年和2007年草地AGB的量较低(整体在30kg/30m2以下),2019年草地AGB的量较高(整体在65kg/30m2左右),其他年份的草地AGB总体较为稳定,波动范围在(45±10)kg/30m2左右,未出现明显的波动。综上,以精度分配权重模型能够解决在反演草地AGB过程中存在部分年份样本点稀少甚至缺失的问题,研究结果为准确估算呼伦贝尔草原长时序、大尺度草地AGB、碳储量等研究提供重要参考。
