基于城乡转型功能分区的京津冀乡村振兴模式探析

乡村振兴战略是我国现代乡村发展理论与实践的创新,核心在于破解乡村地域系统的“五化”问题。乡村振兴的模式及路径探究是乡村振兴的重要研究内容。我国乡村地域辽阔、类型差异万千,因此乡村振兴发展策略的制定必须充分考虑到区域的差异化特征,并在乡村分区、分类的基础上开展乡村振兴模式的探索。本文以京津冀地区为研究范围,从“人口-土地-产业”视角构建城乡转型评价指标体系,根据城乡转型的发展轨迹进行功能分区,并基于分区进行乡村振兴典型模式的梳理,以期形成区域发展样板,为京津冀乡村振兴提供理论参考,并为其他地区乡村振兴模式的梳理提供研究思路和技术支撑。     

Wave height statistical characteristic analysis

When exploring the temporal and spatial change law of ocean environment, the most common method used is using smaller-scale observed data to derive the change law for a larger-scale system. For instance, using 30-year observation data to derive 100-year return period design wave height. Therefore, the study of inherent self-similarity in ocean hydrological elements becomes increasingly important to the study of multi-year return period design wave height derivation. In this paper, we introduced multifractal to analyze the statistical characteristics of wave height series data observed from oceanic hydrological station. An improvement is made to address the existing problems of the multifractal detrended fluctuation analysis (MF-DFA) method, where trend function showed a discontinuity between intervals. The improved MFDFA method is based on signal mode decomposition, replacing piecewise polynomial fitting used in the original method. We applied the proposed method to the wave height data collected at Chaolian Island, Shandong, China, from 1963 to 1989 and was able to conclude the wave height sequence presented weak multi-fractality. This result provided strong support to the past research on the derivation of multi-year return period design wave height with observed data. Moreover, the new method proposed in this paper also provides a new perspective to explore the intrinsic characteristic of data.     

高光谱图像子空间的波段选择

为降低高光谱遥感数据光谱空间的冗余度,提出一种快速的波段选择方法。该方法在波段子空间下进行,依次选择各子空间中方差最大的波段作为初始波段,设定目标函数,然后逐子空间替换波段使得目标性能更加优化,直至没有替换可以使得目标更优为止。在两个公开高光谱影像数据集上对比3种常用波段选择方法(ABC、AP、ABS)来验证提出方法的有效性,实验结果表明:(1)在印第安纳数据上,本文方法与ABC、AP、ABS所选波段子集相比平均相关性分别降低22.04%、52.61%、55.71%,最佳指数分别提高0.58%、51.73%、0.95%,总体分类精度分别提高0.16%、1.39%、23.07%,在搜索效率上与同类型的ABC方法相比提高6.61%—69.02%;(2)在帕维亚大学数据上,本文方法与ABC、AP、ABS所选波段子集相比平均相关性分别降低2.38%、0.51%、32.83%,最佳指数分别提高1.34%、17.97%、12.92%,总体分类精度分别提高0.31%、0.69%、8.53%,在搜索效率上与同类型的ABC方法相比提高19.13%—86.34%。本文提出的波段选择方法能够选择合适的波段子集满足不同的应用需要,是一种有效的波段选择方法。     

Synchronization between fractional-order chaotic systems and integer orders chaotic systems (fractional-order chaotic systems)

Based on the idea of tracking control and stability theory of fractional-order systems, a controller is designed to synchronize the fractional-order chaotic system with chaotic systems of integer orders, and synchronize the different fractional-order chaotic systems. The proposed synchronization approach in this paper shows that the synchronization between fractional-order chaotic systems and chaotic systems of integer orders can be achieved, and the synchronization between different fractional-order chaotic systems can also be realized. Numerical experiments show that the present method works very well.     

Processes controlling cobalt distribution in two temperate estuaries,Sagami Bay and Wakasa Bay,Japan

Concentrations of cobalt (Co) in surface waters from the Sagami River to northern Sagami Bay and from the Yura River to southwestern Wakasa Bay in Japan were determined in order to investigate the factors governing the distribution of this metal during estuarine mixing. Dissolved (<0.2 μm) and particulate (>0.2 μm) Co showed non-conservative mixing behavior with low or mid-salinity maxima within those two estuarine regions, indicating benthic remobilization and/or sewage input apart from riverine input during the estuarine mixing. These results are supported by a suite of complementary measurements of other parameters, such as manganese, phosphate, and suspended particulate matter concentrations. In addition, the concentration ratio of dissolved Co to total Co (dissolved plus particulate) increased along the salinity gradient, implying the potential for desorption of this metal from suspended particulate matter on estuarine mixing.     

沿海区域不同坐标系统转换方法研究

沿海区域的测绘资料主要采用1954年北京坐标系、1980西安坐标系和2000国家坐标系(旧称WGS84坐标系),造成使用不便,需要构建这些系统之间的转换关系。不同方法和不同分区的大量试算表明,1980西安坐标系与WGS84坐标系可以采用7参数转换模型,3个分区和5个分区的精度都能达到0.5 m,其中5个分区的精度较好。由于1954年北京坐标系的特殊性,简单的7参数模型不能确保系统的转换精度,1954年北京坐标系与WGS84坐标系最好采用曲面拟合方法实现坐标转换,整个沿海区域采用6个分区,精度可以达到0.5 m以内的转换要求。     

2006年长江中下游地区梅雨季节划分的探讨

为了建立长江中下游地区梅雨季节的新样本,采用以环流为主导的常规方法,利用NCEP/NCAR逐日再分析资料及长江中下游5站降水资料,对2006年长江中下游地区梅雨季节的特征量进行了诊断分析,并讨论了梅雨与夏季风的关系。结果表明,将6月5候和7月4候分别划为2006年长江中下游地区梅雨季节的起始和结束时间是较为合适的;2006年长江中下游地区梅雨季节对应的梅雨量较常年偏少,这与梅雨季节中印度夏季风和东亚夏季风（包括南海夏季风和副热带夏季风）强度较常年偏弱有关。     

顾及矢量特征的机载LiDAR点云数据压缩方法

LiDAR技术可获取海量点云数据,数据压缩是点云数据预处理的一个重要环节。该文结合大范围城市区域高程范围随区域变化大的特点,提出一种有效的压缩策略。该策略主要通过建立高程方向不均等的三维格网来提高邻域点集的搜索效率,并根据某一压缩准则计算特征量对数据进行压缩。将该策略应用于上海浦东某区域,并与均匀采样法进行比较,证明其能有效提高点云数据压缩效率。     

混合整数最小二乘在GPS定位中的应用

目前针对载波相位双差观测模型中具有整型和浮点型两类参数的特点,常用的方法是先将混合整数最小二乘估计转换为整数最小二乘估计,并以此为准则搜索确定整周模糊度,然后回代解算基线向量。这里提出了一种基于混合整数最小二乘对两类参数同时估计的方法;推导了在未知参数具有先验信息的条件下混合整数最小二乘及整数最小二乘的参数估计准则。最后给出算例验证了基于混合整数最小二乘的参数估计的正确性和优越性。     

航天器交会对接远程导引段的精密轨道确定

探讨了CEI技术在飞船交会对接远程导引段的高精度定位与监控的能力,采用了差分相位延迟和相位延迟率为观测量进行轨道解算,仿真结果表明可满足远程导引段的精度指标。