具有随机状态转移矩阵的Kalman滤波

讨论状态转移矩阵为随机性矩阵时的Kalman滤波方法,并给出滤波的具体算法及分析滤波的收敛特性和参数的取值范围。通过实际算例证实了该滤波方法的有效性。     

基于MRPs无陀螺卫星姿态确定的抗差估计算法

针对精确航天器姿态问题,采用修正罗德里格参数(MRPs)表示姿态,用动力学方程进行角速率的传播,分别基于等价协方差和观测残差统计特性的协方差调整方法,实现UKF算法的抗差效果,并通过仿真验证该方法的有效性。仿真结果表明：在含有粗差的情况下,两种抗差UKF算法均能得到稳定的状态估计值,而第二种方法计算效率更高。     

昆明市城区旱季尘土磁化率特征及环境意义

分析了昆明市区旱季道路尘土样品磁化率特征。结果表明,样品的Xlf的变化范围为96×10-8~9×10-8m3/kg,平均值为46.5×10-8m3/kg,Xfd值变幅为0.3﹪~13.8﹪,平均为2.0﹪;磁化率数值由市中心区向郊区呈下降趋势,且城市不同功能区的磁化率值也存在明显差异,表明影响昆明市街道尘土磁化率因素的多元性,工业活动可能不是昆明市城区道路尘土磁性矿物颗粒最主要来源,而主要是来自市区日常生产与生活活动,特别是昆明市众多机动车辆产生的磁性颗粒物;道路尘土中磁性矿物含量较高,以人为源为主,重金属污染较重。     

济阳坳陷桩海地区下古生界硅化岩溶储集层空间分布模式

基于岩心描述和镜下观察,分析了研究区下古生界硅化岩溶储集层的岩性特征。通过对沟通潜山 断块和古近纪洼陷的边界断层产状、潜山断块内下古生界产状的分析,认为下古生界碳酸盐岩具备埋藏岩溶作 用条件,提出了古近纪沉积物压释酸性水向潜山断块运移的3种方式,即：翘倾端断面补给畅流运移模式、倾 没端断面补给畅流运移模式和背斜凸起两侧双向渗入补给对流循环模式。利用这 3种模式可以合理解释研究区 下古生界潜山硅化岩溶储集层空间分布的特点和规律。翘倾端断面补给畅流运移模式可以解释潜山断块高部位 硅化岩溶层段储集层的发育情况,倾没端断面补给畅流运移模式和背斜凸起两侧纵向渗入补给对流循环模式, 可以解释潜山断块的低部位硅化岩溶层段储集层的发育情况。该模式还可以合理地解释硅化岩溶储集层在下古 生界赋存层位的 “ 穿层性”特点,同时也能够合理解释潜山断块周缘发育硅化岩溶层段,而潜山断块中心地带 很少出现硅化岩溶层段等现象。     

The convergence of GIS and social media: challenges for GIScience

It is hard to believe that 10 years have passed since we wrote our guest editorial for IJGIS (Sui and Goodchild 2001 Sui, D.Z. and Goodchild, M.F. 2001. Are GIS becoming new media?. International Journal of Geographical Information Science, 15(5): 387–390. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). Using the nascent evidence that emerged in the late 1990s, we speculated back in 2001 that geographic information systems (GIS) were rapidly becoming part of the mass media. On the basis of the proposition of GIS as media, we were able to link GIScience with theories in media studies such as Marshall McLuhan's law of the media, which considers modern media as modifiable perceptive extensions of human thought (Sui and Goodchild 2003 Sui, D.Z. and Goodchild, M.F. 2003. A tetradic analysis of GIS and society using McLuhan's law of media. Canadian Geographers, 47(1): 5–17. [Crossref], [Web of Science ®] , [Google Scholar]). Remarkable conceptual and technological advances in GIS have been made during the past 10 years. The goal of this review is to provide an update on the ‘GIS as media’ argument we made 10 years ago and to discuss the new challenges for GIScience posed by the growing convergence of GIS and social media.     

Automatic change detection for road networks from images based on GIS

Up to now, detailed strategies and algorithms of automatic change detection for road networks based on GIS have not been discussed. This paper discusses two different strategies of automatic change detection for images with low resolution and high resolution using old GIS data, and presents a buffer detection and tracing algorithm for detecting road from low-resolution images and a new profile tracing algorithm for detecting road from high-resolution images. For feature-level change detection (FL-CD), a so-called buffer detection algorithm is proposed to detect changes of features. Some ideas and algorithms of using GIS prior information and some context information such as substructures of road in high-resolution images to assist road detection and extraction are described in detail.     

泉州地震台数字地震仪台址的地脉动噪声分析

利用2008年泉州台甚宽频带数字地震仪连续48 h和全年每月连续48 h内白天与夜间各连续4 h的地脉动记录,计算5 Hz、5 s和100s的静态地脉动噪声功率谱密度、1/3倍频程1-20Hz带宽各段的平均静态地脉动噪声有效值、1/3倍频程100-30 s带宽各段的平均静态地脉动加速度噪声有效值,以及上述3个频点和2个...     

http://www.sciencedirect.com/science/article/pii/S1674987111000156

Employing the Unit Soil Carbon Amount (USCA) approach, soil carbon storage was calculated across the Northeast Plain of China based on the Multi-purpose Regional Geochemical Survey conducted in 2004 – 2006 (MRGS). The results indicated that the soil organic carbon (SOC) storage in topsoil (0 – 0.2 m), subsoil (0 – 1 m) and deep soil (0 – 1.8 m) was 768.1 Mt, 2978.4 Mt and 3729.2 Mt with densities of 3327.8 t/km2, 12,904.7 t/km2 and 16,157.5 t/km2, respectively. These values were consistent with national averages, whereas the soil carbon densities showed a clear increasing trend from the southern area of the Northeast Plain (Liaoning), to the middle (Jilin) and the northern Plain (Heilongjiang) — particularly in terms of topsoil carbon density, which increased from 2284.2, to 3436.7 and 3861.5 t/km2, respectively. In comparison to carbon data obtained from the Second National Soil Survey in 1984 – 1986 (SNSS), the topsoil SOC storage values from the MRGS were found to have decreased by 320.59 Mt (29.4%), with an average annual decline of 16.0 Mt (l.73%) over the 20 years. In the southern, middle and northern areas of the plain, soil carbon densities decreased by 1060.6 t/km2, 1646.4 t/km2 and 1300.2 t/km2, respectively, with an average value of 1389.0 t/km2 for the whole plain. These findings indicate that the decrease in soil carbon density varied according to the different ecosystems and land use types. Therefore, ratios of soil carbon density were calculated in order to study the carbon dynamic balance between ecosystems, and to further explore distribution characteristics, as well as the sequestration potential of SOC.     

Evaporation and energy balance estimates over a large inland lake in the Tibet-Himalaya

The process of evaporation from the lake surface is one of the main mechanisms in the energy and water budgets of the lake hydrologic cycle, and an essential component of the water balance especially for inland lakes. In this study, using routine meteorological data as input, a one-layer potential evaporation model was employed to simulate evaporation and energy fluxes over Lake Yamdrok Yumco, the largest high-elevation inland lake in the mountain area of the Tibet-Himalaya in China. Then, the calculation results were compared with the measured values from a big pan evaporator of 20 m² near the lake. The results show that the average annual input radiation flux R ^↓ is 128.2 W m⁻², the lake storage heat flux G is 19.4 W m⁻², the sensible heat flux H is 20.4 W m⁻² and the latent heat flux lE is 107.8 W m⁻². The R ^↓ and G exhibit similar seasonal variations. The lE reaches a maximum in October, lagging nearly 4 months behind the R ^↓ and the G, which indicates the large heat capacity of the lake. The simulated annual evaporation ranges from 1,113.2 to 1,429.1 mm and its mean value is 1,252.5 mm during 1961–2005. The simulated annual evaporation is in good agreement with the measured value, and the measured average lake temperature is as expected when compared with the measured lake surface temperature.