基于事件触发的二阶随机时延系统的有限时间一致

文章研究的是二阶随机时延多智能体系统的有限时间一致性控制.针对在达到有限时间一致性的过程中控制器更新频率过高的问题,设计了一种事件触发控制策略,每个智能体根据状态信息设计了自己的触发条件,当条件违反时才触发事件,使系统能耗和控制器的更新频率均能有效减少,同时利用李雅普诺夫理论和齐次性理论证明跟随者的位置和速度状态能跟踪到领导者并实现有限时间一致.另外,得到了任意两个连续触发时刻间隔的具体值,从而排除芝诺现象.最后,仿真结果验证了理论的有效性.     

基于终端滑模控制的多智能体系统有限时间跟踪控制

针对有向拓扑结构下带领导者的非线性二阶多智能体系统,基于终端滑模控制策略,研究其有限时间一致性跟踪问题;利用快速积分型终端滑模控制理论与有限时间稳定性理论,设计了一类分布式有限时间一致跟踪控制协议,以确保多智能体系统中跟随者对动态领导者的跟踪。提出的控制协议可以使多智能体系统的状态在有限时间内到达并停留在设计的滑模面上,并且能有效削弱抖振。通过数值仿真,验证了所获得的理论结果的有效性。     

多自主水下航行器的有限时间无碰撞协调控制方法

研究了多自主水下航行器有限时间协调控制问题,提出一种基于多智能体控制思想的有限时间跟踪一致性控制律。为实现多AUV系统间的避碰,引入一种虚拟力,并且与所设计的有限时间一致性跟踪控制律进行向量合成, 构成总的控制律来实现对多AUV系统无碰撞的协调控制。仿真验证了所提出控制策略的有效性。     

时滞多智能体系统的事件触发一致性

针对一类时滞非线性多智能体系统,研究了带有时滞的非线性多智能体系统的事件触发固定时间一致性控制问题.设计了一种分布式的事件触发控制策略,利用李亚普诺夫稳定性理论和固定时间稳定性理论,导出了保证系统在固定时间实现一致的充分条件,并通过所给出的分布式的事件触发函数证明了系统能够避免芝诺行为.最后,通过仿真实例验证了结果的有效性.     

基于零和博弈方法的多智能体系统H∞一致性

针对存在外部扰动情形下离散多智能体系统的H_∞一致性问题,利用二人零和博弈方法,一致性协议和外部扰动分别被看作博弈双方参与者,通过寻找二人零和博弈的纳什均衡点,可以设计出针对最坏情形干扰时的最优一致性协议.而获得博弈问题的纳什均衡需要求解耦合Hamilton-Jacobi-Isaacs(HJI)方程,因此给出了解耦方法,并且使用强化学习中的双环策略迭代算法对解耦后的HJI方程进一步求解.最后给出的算例仿真结果验证了提出方法的有效性.     

基于DOBC的多智能体系统一致性协议设计与分析

针对一类具有未知输入扰动的多智能体系统提出一种基于干扰观测器的多智能体一致性协议.首先，在各智能体中引入干扰观测器，抵消输入通道内扰动；其次，在扰动前馈补偿基础上构建基于无向图图论的一致性协议；最后，利用Lyapunov稳定性理论和线性矩阵不等式得出状态一致性误差系统与扰动跟踪系统的稳定性条件.通过仿真算例验证了该算法的可行性.     

离散时间异质多智能体系统的一致性控制

针对由一阶智能体和二阶智能体组成的离散异质多智能体系统,研究其一致性问题.设计无通信时延和具有有界通信时延时的分布式一致性协议,通过将系统转化为自治的离散时间线性时不变系统,运用矩阵理论和代数图论方法,分析得到系统实现一致性的充分条件.获得的充分条件与采样周期、控制参数和系统的拓扑结构有关.证明了系统的一致性不受有界通信时延影响.数值仿真结果验证了理论结果的正确性.     

多机器人系统的鲁棒一致性算法

针对部分信息已知且带有干扰的多机器人系统,设计一种新的鲁棒一致性算法,解决多机器人系统输出一致性问题.首先,给出轮式移动机器人系统的运动学模型,根据全局控制与局部控制策略相结合的思想,建立基于多智能体一致行为的数学描述;其次,提出一种合理的鲁棒性能指标,利用H∞鲁棒控制及微分对策方法,设计多机器人系统鲁棒一致性算法.仿真实验验证了上述算法不仅使多个机器人自主达到速度一致,并有效抑制了干扰.     

带有噪声和时滞的二阶多智能体的一致性

研究了随机二阶时滞多智能体系统的几乎必然指数一致性问题.同时考虑了由Browian运动所导致的随机扰动和系统节点时间延迟两种情况.首先,建立随机二阶时滞多智能体系统的误差动力系统.其次,通过建立适当的Lyapunov泛函,并结合随机分析理论、控制技术以及线性矩阵不等式,从而得到了确保系统达到几乎必然指数一致性的充分性条件.最后,数值仿真的例子证实了所得结论的有效性.     

存在执行器故障的多智能体系统的容错一致性

考虑了同时存在执行器故障以及外部扰动下领航-跟随多智能体系统的容错一致性问题,其中,执行器故障由执行器增益变化来刻画;针对可能的执行器故障,设计具有自适应增益的补偿控制律,并与标称控制律共同作用来实现容错一致性,在进行增益系数以及控制律设计中,均采用相对输出信息而非相对状态信息;通过分析闭环跟踪误差系统的渐近稳定性,给出原来多智能体系统实现容错一致性所需满足的条件.结果表明,在未知扰动以及领航者输入范数满足一定条件下,通过适当选择参数可以实现容错一致性的目标.最后,采用数值仿真验证了所得结果的有效性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.