集值弱向量变分不等式问题解集映射的稳定性

主要讨论一类参数集值弱向量变分不等式问题解集映射的上半连续性,其中参数集值弱向量变分不等式中的算子不是连续的,仅满足v-半连续性及C-伪单调性.相应结论推广了已有文献中的结果.     

金融改革对收入不平等的影响研究——理论解释与实证分析

采集55个新兴市场国家的非平衡面板数据，使用动态门限面板模型实证结果表明，金融改革与收入不平等间存在明显的门限效应，当金融改革水平低于门限值时，金融改革会扩大收入差距；当金融改革水平越过门限值时，金融改革有利于收入差距的缩小。多数新兴市场国家金融改革对降低收入不平等已经发挥正向效应，为缩小新兴市场国家收入差距，必须进一步深化金融改革。     

基于多维空间变异分析的精确农业作业单元自适应决策

针对精确农业技术体系中最佳农艺作业单元大小,该文提出了一种用纵、横探测法推求土壤特性空间变异、作物长势空间变异以及前茬作物产量空间变异等多维空间变异指数,进而按一定农学原则决定最佳农艺作业单元尺寸的自适应解决方案。结果表明,用该算法确定的农艺作业单元尺寸进行变量施肥,平衡效果良好率在90%以上。该算法的另一特点是,对矢量和栅格数据具有同样的适用性,较易在矢栅混合型GIS上实现。     

Long-time precipitation reduction and nitrogen deposition increase alter soil nitrogen dynamic by influencing soil bacterial communities and functional groups

The effects of precipitation reduction and nitrogen deposition increase on soil bacterial communities and functions impact soil nitrogen cycling. Seasonal changes could modify the effects of precipitation reduction and nitrogen deposition increase on bacterial communities and functions by changing soil environments and properties. Understanding soil microbial communities and the seasonal response of functions to precipitation reduction and nitrogen deposition increase may be important for the accurate prediction of changes in the soil nitrogen dynamics. Thus, a long-term field simulation experiment of nitrogen deposition increase and throughfall exclusion was established to investigate soil bacterial communities’ response to nitrogen deposition increase and/or precipitation reduction, with no nitrogen deposition increase and no precipation reduction as a control, in a temperate forest. We examined soil bacterial communities (Illumina sequencing) under different treatments during the winter, freezing-thawing cycle periods (FTCs), and growing season. The bacterial functional groups were predicted by the FAPROTAX database. The results showed that nitrogen deposition increase, precipitation reduction, the combined effect of nitrogen deposition increase and precipitation reduction, and seasonal changes significantly altered the soil bacterial community composition. Interestingly, by combining the result of a previous study in which nitrogen deposition increase increased the nitrous oxide flux in the same experimental system, the loss of soil nitrogen was increased by the decrease in denitrification and increase of nitrification bacteria under nitrogen deposition increase, while ammonification bacteria significantly increased and N-fixing bacteria significantly decreased with precipitation reduction compared to the control. In relation to seasonal changes, the aromatic-degrading, cellulolytic, and ureolytic bacteria were lowest during FTCs, which indicated that FTCs might inhibit biodegradation. Nitrification and nitrite-oxidizing bacteria increased with nitrogen deposition increase or precipitation reduction and in FTCs compared to the control or other seasons. The interaction between treatment and season significantly changed the soil bacterial communities and functions. These results highlight that nitrogen deposition increase, precipitation reduction, seasonal changes, and their interactions might directly alter bacterial communities and indirectly alter the dynamics of soil N.     

斜拉索-磁流变阻尼器非脆弱减振控制器研究

以抑制振荡幅值和时间为目标,针对斜拉索-磁流变阻尼器外部扰动和减振控制器参数不确定性问题,提出一种多性能指标约束下的非脆弱减振控制器设计方法。基于线性矩阵不等式(LMI)理论,利用H_∞性能指标抑制外部扰动,并以区域极点配置表征减振控制的快速性与稳定性,以方差表征小振幅和振动速度。通过Matlab中LMI工具箱对多LMI约束和线性目标函数的凸优化问题进行求解,给出了多性能指标约束的非脆弱减振控制器设计形式。以浙江省某跨海大桥C22、C13号斜拉索为实例,进行了仿真验证。结果表明,在不同随机扰动下,该方法设计的减振控制器使不同拉索振动状态的振幅分别降低57. 805%、74. 395%,收敛时间分别缩短56. 705%、77. 845%。     

双复合Poisson风险模型与保险业效益分析

本文是对古典风险模型的推广，主要研究保费收入过程为双复合Poisson过程的风险模型，运用鞅的方法得出了破产概率满足的Lundburg不等式。     

管理风险多维度量模型的建立与检验

分析多维风险度量模型中影响风险的因素间的逻辑关系,构建了可管理风险的多维度量模型,然后应用BP神经网络对该模型进行检验。检验结果表明该模型能够对可管理的风险进行度量。     

网络化控制系统连续动态输出反馈控制器设计

研究一类网络化控制系统的连续动态输出反馈控制器的设计问题.假设网络化控制系统的被控对象为一个定常时滞系统,其网络诱导时滞是随机的且小于一个采样周期的情况下,将此类网络化控制系统模型化为一个混合系统.然后采用李亚普诺夫函数、线性矩阵不等式的方法推导出了该网络化控制系统渐近稳定的充分条件.根据此充分条件,给定一个等式约束,然后通过求解一组线性矩阵不等式,获得了连续动态输出反馈镇定控制器.最后给出一个具体的数值和仿真实例说明了此设计方法是有效的.     

N维K—拟共形映照的一个局部最大原理

In this paper, we have studied the distortion properties for N-dimensional K-quasiconformal mappings and shown that the distortion in the neighborhood of the boundary points can be controled by the distortion in the boundary points by using quasihyperboli     

Dietary shifts in the crystal darter (Crystallaria asprella) after large-scale river fragmentation

Abstract –  The crystal darter, Crystallaria asprella (Jordan), is a benthic, riverine specialist, rare throughout its range and critically imperiled in the state of Mississippi. Construction of the Tennessee–Tombigbee Waterway has fragmented a once continuous population of this species into several subpopulations in remaining, free-flowing tributaries of the system. In spite of this fragmentation and population subdivision, we collected numerous individuals from the waterway during summer 2004 and 2005. Because of the lentic conditions in the waterway, we questioned whether a dietary shift accompanied darters occupying this new environment. We also obtained museum specimens from the Tombigbee River before waterway construction and quantified and compared diets among the historical, tributary (contemporary) and waterway specimens. We hypothesised that waterway specimens would differ significantly in diet from both historical and tributary specimens, and that the latter two groups would have similar diets. Multiresponse permutation procedures indicated that all three groups were significantly different from each other and indicator species analysis identified significant indicator taxa for waterway and tributary specimens. Using a null model approach, dietary overlap was significantly greater than expected for tributary and waterway specimens, and significantly less than expected for waterway and historical specimens. Dietary plasticity was evident for crystal darters across space and time, but it remains unknown whether waterway individuals represent a population sink or are actively dispersing from nearby population sources.