基于地统计学的多维时间序列模型及其在生态学中的应用

基于地统计学半变异函数发展了一种新的多维时间序列最优阶数判断方法,并结合支持向量回归建立了既反映样本集动态特征又体现环境因子影响的非线性多维时间序列分析预测模型(GS-SVR). 用一步预测法对两个生态学样本集的预测结果表明,GS-SVR预测精度高,并具结构风险最小、非线性、避免过拟合、泛化推广能力强等诸多优点.     

解单障碍问题的非重叠区域分解法（I）：两子域情形

考虑二阶椭圆变分不等式，提出了两子域情形的非重叠区域分解，得到了算法的收敛性和几何收敛速度。     

一类自由边界问题之正则性和不存在性

本文应用De Giorgi和O.A.Ladyzenskaya等研究方程的方法来直接讨论所谓的含超线性增长项的非线性椭回型变分不等式(1),得到了其解的有界性,H lder连续性和W~(2,s)正则性,并建立了一类半线性椭圆型障碍问题的Pohozaev型恒等式,进而得到其解之不存在性的有关结果.     

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%。     

东海北部鱼类组成特征分析

利用1997-2000年东海北部(29°30′～33°00′N,122°30′～128°00′E)四个季节的底拖网调查资料,选取生物量占总生物量90％的前27种鱼类,运用聚类分析和多维标度分析法,研究了东海北部鱼类组成的空间格局特征。结果显示东海北部鱼类组成可分为三个群聚类型,即近海群聚、较深海域群聚和外海群聚。近海群聚的主要种类有凤鲚(Coilia mystus)、龙头鱼(Harpadon nehereus)、黄鲫(Setipinna taty)等;较深海域群聚的主要种类有鳀(Engraulis japonicus)、带鱼(Trichiurus japonicus)、日本鲭(Scomber japonicus)、鳄齿鱼(Champsodon capensis)、细条天竺鲷(Apogon lineatus)、发光鲷(Acropoma japonicum)等;而竹(竹夹)鱼(Trachurus japonicus)、星康吉鳗(Conger myriaster)、黄鲷(Taius tumifrons)、水珍鱼(Argentina kgoshimae)、日本海鲂(Zeus fober)、绿鳍马面鲀(Thamnaconus sepremtrionalis)等为外海群聚的主要种类。同时分析了水深、底层温度、底层盐度等环境因子与鱼类群聚的关系,表明影响鱼类群聚的主要环境因子有水深、底层盐度。不同群聚间的种类分布是重叠交错的,并没有明显的群聚边界,但密集分布海域各异,不同群聚的种类组成在不同季节具有一定的持续性,其种类组成保持了相对的稳定。     

黑龙江省城乡居民收入差距分析

通过考察城市居民和农村居民内部收入差距变动以及城乡差距的变动,分析得出黑龙江省城乡居民收入差距呈逐渐扩大的趋势.为此,从改革农产品价格形成机制促进农民增收、加大财政支农力度推进农业现代化进程、推进城市化进程、加强基础教育与职业技术教育等方面提出了缩小黑龙江省城乡居民收入差距的对策建议.     

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.     

关于一类集值拟变分不等式的广义投影算法

引入并研究了一类新的广义非线性集值强隐拟变分不等式，通过用投影方法，证明了这类变分不等式的解等价于一类不动点问题的解．基于这类不动点问题，我们构造了一个迭代算法，在没有紧性的条件下，证明了这类变分不等式解的存在性；同时，还证明了由迭代算法所产生的迭代序列收敛于这类变分不等式的解．     

时滞大系统解的有界性和稳定性

本文利用向量V函数和时滞微分不等式研究了时滞大系统解的有界性和稳定性,获得了一个有界性充分条件和稳定性的一些简单的代数判据。