基于RS的宁波市绿地空间分布的GIS初步研究

随着城市环境问题的日益突出,建立宁波市绿地空间分布信息系统有重要的意义。本文应用RS与GIS等现代技术最新理论和方法对宁波市绿地空间分布进行分析,提出宁波市绿地空间分布GIS的体系结构,详细设计了系统的实现技术路线和途径。     

基于贝叶斯模型的器测、古气候重建与气候模拟数据的融合试验

气象部门馆藏的西部最早的器测气象资料始于20世纪30年代,不能满足建立20世纪以来中国气候变化序列的需求,而古气候重建或气候模拟资料则可以延伸到器测时代以前。为了探讨长序列多源气候资料序列融合方法,采用贝叶斯方法对中国北疆地区8条树轮气温重建资料、器测资料与国际耦合模式比较计划第5阶段（CMIP5）模式模拟资料进行了融合试验。首先利用器测资料对气温代用资料进行校验与网格重建,并以此作为贝叶斯模型的先验分布,然后,用泰勒图选出了该区域气候模拟效果最佳的几个模式;最后将网格重建和气候模拟序列用贝叶斯模型进行了融合试验。结果表明,贝叶斯融合模型能有效提取各种数据来源的有用信息进行融合,融合结果的长期变化（线性）趋势更接近器测气候序列,并在一定程度上提高了序列的精度,减小了结果的不确定性;并且,融合结果能够纠正先验分布及气候模拟数据的明显偏差,为长年代气候序列重建提供了一个可行的思路。      

IMPACT OF DIABATIC PROCESSES IN AGCM ON 4-DIMENSIONAL VARIATIONAL DATA ASSIMILATION*

The impact of diabatic processes on 4-dimensional variational data assimilation (4D-Var) was studied using the 1995 version of NCEP's global spectral model with and without full physics.The adjoint was coded manually.A cost function measuring spectral errors of 6-hour forecasts to "observation" (the NCEP reanalysis data) was minimized using the L-BFGS (the limited memory quasi-Newton algorithm developed by Broyden,Fletcher,Goldfard and Shanno) for optimizing parameters and initial conditions.Minimization of the cost function constrained by an adiabatic version of the NCEP global model converged to a minimum with a significant amount of decrease in the value of the cost function.Minimization of the cost function using the diabatic model, however,failed after a few iterations due to discontinuities introduced by physical parameterizations.Examination of the convergence of the cost function in different spectral domains reveals that the large-scale flow is adjusted during the first 10 iterations,in which discontinuous diabatic parameterizations play very little role.The adjustment produced by the minimization gradually moves to relatively smaller scales between 10-20th iterations.During this transition period,discontinuities in the cost function produced by "on-off" switches in the physical parameterizations caused the cost function to stay in a shallow local minimum instead of continuously decreasing toward a deeper minimum. Next,a mixed 4D-Var scheme is tested in which large-scale flows are first adiabatically adjusted to a sufficient level,followed by a diabatic adjustment introduced after 10 to 20 iterations. The mixed 4D-Var produced a closer fit of analysis to observations,with 38% and 41% more decrease in the values of the cost function and the norm of gradient,respectively,than the standard diabatic 4D-Var,while the CPU time is reduced by 21%.The resulting optimal initial conditions improve the short-range forecast skills of 48-hour statistics.The detrimental effect of parameterization discontinuities on minimization was also reduced.     

基于NCEP FNL资料的山西岢岚地区雨雪天气诊断可信度分析

基于山西岢岚地区2005—2014年共1218个雨雪天气日的NCEP FNL资料(1°×1°)与探空资料,采用偏差、绝对差、相关系数和偏差区间占有率的统计方法,对常规物理量(温度、相对湿度、纬向风和经向风)和诊断物理量(T_800-500、T_d800和TT_d700)进行统计分析。结果表明:常规物理量中的温度平均偏差值和绝对差值最小、相关系数值最大,分别为-0. 22℃、1. 02℃、0. 90,可信度最高;而相对湿度的平均偏差值和绝对差值最大、相关系数值最小,分别为12. 31%、19. 68%和0. 63,可信度最低;纬向风和经向风的可信度相差不大,略低于温度;诊断物理量T_800-500、T_d800和TT_d700的偏差值分别为-0. 08℃、1. 50℃和2. 79℃,绝对差值分别为1. 21℃、3. 33℃和4. 14℃,相关系数值分别为0. 95、0. 92和0. 74,偏差值为[-5,5]占总数百分比分别为98. 77%、80. 30%和75. 04%。即T_800-500可信度最高,TT_d700指数可信度最低。     

Finding the most variable stars in the Orion Belt with the All Sky Automated Survey

We look for high‐amplitude variable young stars in the open clusters and associations of the Orion Belt. We use public data from the ASAS‐3 Photometric V ‐band Catalogue of the All Sky Automated Survey, infrared photometry from the 2MASS and IRAS catalogues, proper motions, and the Aladin sky atlas to obtain a list of the most variable stars in a survey area of side 5° centred on the bright star Alnilam (ε Ori) in the centre of the Orion Belt. We identify 32 highly variable stars, of which 16 had not been reported to vary before. They are mostly variable young stars and candidates (16) and background giants (8), but there are also field cataclysmic variables, contact binaries, and eclipsing binary candidates. Of the young stars, which typically are active Herbig Ae/Be and T Tauri stars with Hα emission and infrared flux excess, we discover four new variables and confirm the variability status of another two. Some of them belong to the well known σ Orionis cluster. Besides, six of the eight giants are new variables, and three are new periodic variables (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

北京大灰厂试验场重力变化特征及其解释

介绍了北京大灰厂试验场（简称京西试验场）的概况，对１９９３年３月以来重力重复观测资料进行了处理。计算了各期重力观测精度，结果显示１９９３年３月～１９９５年５月京西试验场存在一定重力变化。采用给定的模型反演了八宝山断层介质的密度变化，认为断层破碎带介质密度的变化可能是引起地表重力变化的主要因素     

gPhone重力仪网络数据采集系统中Web服务功能的设计与实现

针对gPhone重力仪网络数据采集系统,开发了一套嵌入式Web服务系统。基于uClinux平台和轻量级BOA Web服务器,利用C语言编写通用网关接口(CGI)程序,实现了远程数据下载及仪器监控等功能。     

Developing constitutive models from EPR‐based self‐learning finite element analysis

A constitutive model that captures the material behavior under a wide range of loading conditions is essential for simulating complex boundary value problems. In recent years, some attempts have been made to develop constitutive models for finite element analysis using self‐learning simulation (SelfSim). Self‐learning simulation is an inverse analysis technique that extracts material behavior from some boundary measurements (eg, load and displacement). In the heart of the self‐learning framework is a neural network which is used to train and develop a constitutive model that represents the material behavior. It is generally known that neural networks suffer from a number of drawbacks. This paper utilizes evolutionary polynomial regression (EPR) in the framework of SelfSim within an automation process which is coded in Matlab environment. EPR is a hybrid data mining technique that uses a combination of a genetic algorithm and the least square method to search for mathematical equations to represent the behavior of a system. Two strategies of material modeling have been considered in the SelfSim‐based finite element analysis. These include a total stress‐strain strategy applied to analysis of a truss structure using synthetic measurement data and an incremental stress‐strain strategy applied to simulation of triaxial tests using experimental data. The results show that effective and accurate constitutive models can be developed from the proposed EPR‐based self‐learning finite element method. The EPR‐based self‐learning FEM can provide accurate predictions to engineering problems. The main advantages of using EPR over neural network are highlighted.     

点模式条件下的犯罪嫌疑人时空同现模式挖掘与分析

现有时空同现模式挖掘方法因其在空间和时间频繁阈值等参数值的设定上存在困难且缺乏客观依据的问题而难以被应用到犯罪地理研究中。为此,本文通过引入时空状态同现模式和最小时空参与率等概念对现有挖掘方法进行了重新建模,并结合广义Grubbs异常值检验提出了一种点模式分布下的犯罪嫌疑人时空同现模式挖掘框架。基于该框架对中国某省部分犯罪嫌疑人的真实移动轨迹数据的实验分析结果表明,本文所提出的方法能够有效地挖掘出嫌疑人间显著的时空同现模式,且这些模式的时空分布特征不仅与犯罪活动易发生在非农业生产区这一共识基本相符,还与日常活动理论的基本观点相适应。本文拓展了时空同现模式挖掘在犯罪地理研究中的应用,研究成果对公安机关等执法部门在重点监控某些犯罪嫌疑人以及合理分配和部署警力资源方面具有重要意义。     

卫星海洋遥感数据的无损压缩及解压算法

在分析卫星海洋遥感单轨三级数据产品特征的基础上,针对游程编码无损压缩算法特征,提出了优化游程编码压缩算法,运用该算法实现了海洋遥感三级数据产品的无损压缩,并与流行的WinRAR压缩软件进行了比较测试,结果表明上述算法对海洋遥感数据均有较高的压缩率,优化游程编码压缩算法在空间复杂度及时间复杂度上均有明显的比较优势,可极大节约海洋遥感数据的存储与共享发布空间。