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1980西安坐标系与2000坐标系坐标成果转换方法及精度分析

利用不同的解算软件,采用三维七参坐标转换模型和二维四参坐标转换模型,把1980西安坐标系成果转换成2000坐标系成果,利用大量检核点进行坐标转换成果精度检查,并对检查点点位精度做了详细的统计、分析;不仅阐述坐标转换方法和要求,而且得出在2种坐标转换模型应用的条件与要求。     

转型期长春市就业结构的空间分异

在经济体制改革及产业空间重构初期,利用2000年第五次人口普查数据,以街道和乡镇为基本单位,运用因子生态分析和聚类分析方法研究了长春市这一老工业基地就业空间结构的特征。研究表明:① 处在特定历史条件下的长春市工、居分离现象并不明显;② 根据因子分析的结果,得到受教育水平、普通收入群体、外来人口比重、性别分化程度四个主要因子对2000年长春市就业空间结构影响较大;③ 运用聚类分析法将长春市划分为6大就业类型区:混合就业区、传统产业区、科技教育集中区、物流业集中区、以农业为主的远郊区、新兴产业集中区,并最终得出长春市就业结构的空间形态特征为:单核心、混合圈层式、综合扇形要素的空间结构模型。     

A Study of the Extratropical Transformation of Typhoon Winnie （1997）

The complicated evolutive process of how a tropical cyclone transforms into an extratropical cyclone is still an unresolved issue to date, especially one which arises in a weakly baroclinic environment. Typhoon Winnie （1997） is studied during its extratropical transformation stage of extratropical transition （ET） with observational data and numerical simulations. Results show that Winnie experienced its extratropical transformation to the south of the subtropical high without intrusion of the mid-latitude baroclinic zone. This is significantly different from previous studies. Analyses reveal that the cold air, which appeared in the north edge of Winnie circulation, resulted from the precipitation drag and cooling effect of latent heat absorption associated with the intense precipitation there. The cooling only happened below 3 km and the greatest cooling was below 1 km. With the cold air and its advection by the circulation of Winnie, a front was formed in the lower troposphere. The front above is related not only to the cooling in the lower level but also to the warming effect of latent heat release in the middle-upper levels. The different temperature variation in the vertical caused the temperature gradient over Winnie and resulted in the baroclinicity.     

Pseudo-static bearing capacity of shallow foundations on heterogeneous marine deposits using limit equilibrium method

Abstract

By application of the limit equilibrium method associated with Coulomb failure mechanism, the effect of variation of undrained shear strength with depth on seismic bearing capacity was evaluated. The approach followed in this study to take into account seismic forces is pseudo-static. It is also assumed that the occurrence of an earthquake does not have any effects on the values of soil cohesion. Two different marine soil deposits exhibiting linear and bilinear variations of undrained shear strength with depth were considered. The undrained bearing capacity factor has been computed as a function of dimensionless parameters of λ₁B/c₀, λ₂B/c₀, and Z_t/B. The results of this paper have been compared with solutions reported in the literature, and the consistency of the results confirmed the ability of Coulomb failure mechanism and its corresponding limit equilibrium method formulation in static condition. Furthermore, the pseudo-static bearing capacity of shallow foundations on heterogeneous marine deposit is addressed. Finally the results of this study presented in the form of table and design charts.     

Derivation and assessment of a bivariate IDF relationship using paired rainfall intensity–duration data

A procedure is presented for developing a rainfall intensity–duration–frequency (IDF) relationship that is consistent with bivariate normal distribution modeling. The Box–Cox transformation was used to derive the relation and two methods of determining the parameters of this transformation were evaluated. To assess the uncertainty of the parameters, a confidence interval was constructed and verified with the non-parametric bootstrap method. Additionally, the effect of sample size on the bivariate normality assumption was examined. Case studies, based on data from significant gauge stations in Korea, were performed. The result shows that the use of the bivariate normal model as an IDF relationship is particularly recommended when the available data size is small.     

Chaotic dynamics analysis and control of iterative procedure of capacity spectrum method

The capacity spectrum method (CSM), capable of predicting the demands of forces and deformations of the inelastic system, has been applied in the ATC and FEMA guidelines. The deformation of an inelastic system is solved iteratively by using the equivalent linearization for CSM, which actually forms a nonlinear map or discrete dynamical system. However, the iterative procedure of CSM did not converge for some inelastic systems, and the complicated dynamical phenomena for the solutions such as the periodic oscillation, period-doubling bifurcation and chaos may occur, which were shown in the bifurcation plots of iterative map of the simplified CSM in ATC40 and FEMA440. This paper presents a novel method to analyze and control the non-convergence of the iterative procedure of CSM from the perspective of chaotic dynamics. The Lyapunov exponent of the dynamical system is employed to identify the evolutional state and stability of solutions. Finally, the stability transformation method as a simple, versatile and effective chaos feedback control approach is applied to control the convergent failure of CSM in ATC40 and FEMA440. The numerical results illustrate that the stability transformation method can capture the desired fixed points of the dynamical system and obtain the stable convergent solutions of CSM.     

基于面向对象的地图投影转换模块设计

以基于面向对象的方法实现地图投影转换模块设计,探讨该方法在地图投影转换中以及具体投影转换模块的设计及实现,在VC6.0平台下通过相关接口的建立以及地理坐标系和投影坐标系两大主要类的设计和扩充,实现地理坐标系间、投影坐标系间或两者间的投影转换.该模块有利于快速、高效编程的实现,并具有扩展性强和易于维护等优势.     

用EDAS-3型数据采集器对倾斜仪进行数字化改造

用EDAS-3型16位地震数据采集器和MDS-2710数传电台对克拉玛依地震台井下摆倾斜仪进行数字化遥测改造.结合改造实例,详细介绍了新观测系统的实现方法和应用效果,提出一套完整的解决方案.改造后的新观测系统的工作范围、采样率和测量精度均高于国家行业标准,工作稳定可靠.