信息化背景下提高《测量学》教学质量的几点思考

针对目前测量学教学中面临的一些问题，对新的技术背景下，如何提高测量学课程的教学质量提出了一些看法。     

感应凝壳熔炼悬浮驼峰数值模拟研究

采用计算机模拟方法,定量研究了安培.匝、坩埚开缝数、不同合金以及线圈位置对悬浮驼峰高度的影响。结果发现,悬浮驼峰的高度随着加载安培.匝数值的增大而呈线性增高。每增加1000A.匝,驼峰高度增加4.2mm。开缝数小于40时,悬浮驼峰的高度和坩埚开缝数成正比,坩埚开缝数每增加1,驼峰高度增加0.6mm;开缝数大于40时,悬浮驼峰高度随坩埚缝数增加而缓慢提高。炉料的相对磁导率越小,悬浮驼峰的高度越高;合金的密度越大,悬浮驼峰的高度越低。Ti-48Al-2Cr合金的密度最小,其悬浮驼峰高度最高;Ti-15V-3Cr合金的密度最大,其悬浮驼峰高度就最低。     

基于SINS/GNSS的航空矢量重力测量数据处理方法研究

航空矢量重力测量是未来高效测定中高频地球重力场信息的先进技术,与地面重力测量、海洋重力测量和卫星重力测量技术相互补充。本文介绍了基于捷联惯性导航系统/全球卫星导航系统(SINS/GNSS)的航空矢量重力测量的原理,重点讨论了航空矢量重力测量的数据预处理、数据归算、带限地形影响、向下延拓及大地水准面确定等问题,为发展我国航空矢量重力测量技术提供参考。     

北斗卫星授时接收机的设计与实现

针对北斗卫星导航系统的时钟高稳特性,研究了高精度、低成本授时接收机的设计和实现方法。介绍了授时接收机从北斗卫星提取授时时标的设计方案,对方案中各部分做了功能分析。对产生授时时标中的关键环节、本地时钟的选择、本地时钟钟差的处理、卫星位置偏差的处理和授时时标合成策略进行了阐述。给出了授时系统的测试方法,分析了性能指标,测试结果表明能够达到优于100ns(1σ)的授时精度。     

Phase and amplitude measurements for high bandwidth optical signals

In this paper a novel technique for obtaining the amplitude and phase of optical pulses with time extents as short as tens of ps is presented. The method which is based on the transport-of-intensity equation only requires, for a practical realization, of passive fiber optic devices. It employs as the main component a dispersive element with a known second order dispersion coefficient. Two different setup implementations are considered, for which simulations are carried out in order to test the method performance taking into account both, realizable models of the involved devices and typical pulses found in optical transmission systems. The characterization of optical pulses affected by dispersion and nonlinear effects, such as self-phase modulation, is used to evaluate the performance of the method and show the practical feasibility of the future implementation.     

Fuzzy expert system for land reallocation in land consolidation

One of the most important steps of land consolidation projects is land reallocation studies. In Turkey, reallocation studies carried out in the scope of land consolidation projects are made according to farmer preferences (interviews). In addition to interview-based land reallocation model, mathematical models have been used in the previous optimization studies for reallocation procedure. Recently, fuzzy logic method, which is capable of modeling human mindset and used when other forms of mathematical models cannot be developed, has also been applied to the field of geomatic engineering, as well as in other engineering branches.This study examined the applicability of a fuzzy logic method at the reallocation stage of land consolidation study, where development of an accurate mathematical model was not possible. The results obtained from the fuzzy logic-based land reallocation model were compared with those obtained from the interview-based land reallocation model. Farmers were surveyed to determine which land reallocation model they preferred. The results indicate that 80.5% of the participant landholdings were satisfied with the fuzzy logic-based reallocation land model, while 50% were with the interview-based land reallocation model.     

利用GOCE卫星重力场模型确定高分辨率地转流

高分辨率、高精度地转流的探测是海洋学研究的目标之一.选用海洋环流探测卫星(GOCE)、气候实验卫星(GRACE)2种卫星重力场模型,结合卫星测高获取的平均海面高模型,计算了分辨率为15′×15′的稳态海面地形(MDT)和全球地转流,利用GOCE卫星重力场模型解算的结果在分辨率和精度上均高于利用GRACE模型解算的结果;选择GOCE最新重力场模型GO_CONS_GCF_2_TIM_R4,ITG-GOCE02和JYY-GOCE02S,联合高精度GOCE卫星重力场模型和高分辨率CNES_CLS09MDT模型的组合方法,得到的地转流结果基本等于或高于仅利用MDT模型得到的结果,可以有效恢复滤掉的MDT(利用GOCE卫星重力场与平均海面高模型计算得到)中的高频信息,实现对流幅为几十千米的海洋环流的探测,使地转流更接近于真实特征.     

面向对象的海域使用变化遥感监测

基于SPOT-5和WorldView-2高分辨率遥感影像,采用面向对象的分类方法,通过多尺度图像分割,获取海域使用地物斑块;结合影像光谱特性、纹理特征等信息建立分类规则,提取海域使用信息,并通过空间叠置分析来定量分析研究区海域使用变化情况.结果表明,面向对象的多尺度分割方法有效提高了分类精度.该研究也分析了海域使用变化情况,研究区内变化主要集中在建筑用地的扩张上.该研究对研究区治理海洋有重要意义.     

地基GPS遥感大气水汽含量中加权平均温度获取方法的比较分析

在利用地基GPS进行大气水汽遥感时,加权平均温度对水汽遥感结果起着举足轻重的作用.对加权平均温度的获取方法进行了列举和比较,得出了一些有益的结论.     

基于文化框架的随机粒子群优化算法

提出了随机粒子群优化算法(rPSO),并将其与标准PSO纳入到文化算法(CA)框架中,建立了基于文化框架的随机粒子群优化算法(CA-rPSO)。该算法以rPSO作为信念空间的进化算法,以PSO作为群体空间的进化算法,形成了两者独立并行进化的\"双演化双促进\"机制。选取5个测试函数进行了仿真实验分析并与其他算法进行了比较,结果表明CA-rPSO的寻优性能得到显著提高,且算法简单、易于实现。