扩频通信中基于非抽取小波包变换的抗窄带干扰算法     

尹艳群  王玲 《成都信息工程学院学报》2005,20(3):279-281

提出了直接序列扩频通信系统中抑制窄带干扰的一种算法。该算法是将频移与非抽取小波包变换结合起来的一种方法。仿真结果表明该算法具有很好的鲁棒性，并且误比特率较低。  相似文献   

实参数与复参数混合域最小二乘平差方法     

刘志平  李思达  朱丹彤  余航 《测绘科学技术学报》2017,(6):551-555

针对平差问题同时含有实数域参数和复数域参数的情形,提出了实参与复参混合的测量平差建模思路,并导出了相应的混合域最小二乘平差方法。该方法统一概括了实最小二乘和复最小二乘方法,其估计过程包括两步:基于零空间算子的实参数平差估计和复数平差模型的复参数估计。通过等价变换将实数域投影变换模型、直接线性变换模型分别重构为相应的混合域平差模型,有效降低法方程求逆维数,从而提高建模和平差计算效率。应用结果及分析验证了本文所提方法的正确性和有效性。  相似文献   

土壤吸附汞测量与直流激电法结合寻找地下水     

段来成 《物探与化探》2008,32(6)

赣北一个隐覆红盆地,上部为30~50 m厚的第四系覆盖层,下部为第三系红砂岩,找水困难。采用土壤吸附汞测量和直流激电法找水,通过分析、总结测区地下水的赋存特征,明确找水方向,优选出好的找水区段,取得了良好的效果。该地已成为一个中型地下水源地,日产水量3万t以上。由此可见,物化探方法结合使用,是红层地区寻找地下水资源的一种行之有效的手段。该方法的特点是经济、快速、方便,在厚覆盖区反映能力强,具有广泛的应用前景。  相似文献   

Effects of microbe mineral contacting on the dissolution of metal sulfides: a preliminary study on chalcopyrite dissolution mediated by Acidothiobacillus ferrooxidans.     

SU Gui-Zhen LIU Jian-Jun LIU Xian-Cai LI Juan HAN Xiao-Dong WANG Rui-Yong WANG Ru-Cheng 《地学前缘》2008,15(6):100

  相似文献   

三维坐标转换参数求解的一种直接搜索法   总被引：1，自引：0，他引：1  

曾怀恩  黄声享 《武汉大学学报(信息科学版)》2008,33(11):1118-1121

采取了两步措施简化三维坐标转换非线性模型:①旋转矩阵的3个旋转角用一个反对称矩阵的3个独立元素代替,将旋转矩阵由反对称矩阵构成Lodrigues矩阵;②将坐标转换7参数模型变换成基线向量模型,消去平移3参数.然后,采用遗传算法与模式搜索法相结合的一种直接搜索法求解参数.算例表明,该算法是可行的.最后,从坐标转换精度的角度时基线向量模型原点与公共点的选取进行了分析,结论是原点选取的点的精度相对较高时坐标转换精度相对较高,公共点的选取以3～5个精度高的点为宜.  相似文献   

德国在华知识密集制造业投资进入方式的时空特征及区位影响因素   总被引：7，自引：1，他引：6  

符文颖  吴艳芳 《地理学报》2017,72(8):1361-1372

外资知识密集型制造业进入中国市场,对中国制造业升级转型起着一定的作用。本文围绕区域制度环境和区域吸收能力,探讨影响知识密集型企业进入方式的区域环境,旨在揭示知识密集型产业的外商进入方式的地理驱动机制,有利于加深理解在经济发展方式转型的时代背景下,区域与城市获得外生技术发展动力的机制。采用从1982-2014年德国在华投资企业数据库,结果发现,德国知识密集型制造企业在中国的投资呈现由沿海地区向内陆地区扩张、沿海中心城市向周边城市扩散的时空趋势,并且在1995年后,其进入方式从合资为主向独资为主转变。逻辑计量模型显示,德国知识密集型制造企业的进入方式受到多项区位因子的影响,其中地方人力资源水平和产业专业化水平是知识密集型制造企业选择以合资方式的进入中国市场的重要区位因素,表明区域知识吸收能力是形成全球—地方战略协同的关键变量;另一方面,实际使用外资存量和地方专利授权量这两个区位影响因素则会显著促成知识密集型制造企业采用独资的进入决策,反映了区域制度环境对吸引以知识产权保护为战略核心的知识密集型制造业的作用。  相似文献   

‘They are stealing my island’: Residents’ opinions on foreign investment in the residential tourism industry in Tamarin,Mauritius          下载免费PDF全文

Tessa Wortman  Ronnie Donaldson  Guus van Westen 《Singapore journal of tropical geography》2016,37(2):139-157

The small nation of Mauritius in the Indian Ocean, once a poor sugar plantation island, has successfully diversified and expanded its economy since independence, by attracting foreign investment in manufacturing and modern service industries. Tourism is a major part of the ‘Mauritian Miracle’; in recent years residential tourism—attracting wealthy foreigners to take up semi‐permanent residence—has become a growth industry transforming coastal areas like Tamarin. Based on in‐depth interviews among 17 residents of Tamarin, this paper looks at how local people perceive the changes residential tourism is causing in the local area. It appears that while the majority is positive about economic changes like more jobs and income opportunities, and to some extent about improvements in infrastructure and services, there are growing misgivings about some of the social impacts. Notably, the increasing scarcity of land and rising house prices are making it impossible for growing numbers of local people to afford a place to live, resulting in growing squatter settlements in the area. Such growing social disparities challenge the Mauritian development model and may undermine its stability. These undesirable effects call for careful management of tourism development, incorporation of sustainability standards and attention to the position of major stakeholder groups, such as local residents.  相似文献   

Spatial inequality of foreign direct investment in China: Institutional change,agglomeration economies,and market access     

《Applied geography (Sevenoaks, England)》2016

The spatial inequality of foreign direct investment (FDI) can intensify uneven economic development. As globalization and economic transition proceeds, foreign investors are changing their behaviors in FDI location, based on institutional change and agglomeration effects. In order to reduce the inequality, this research employs spatial statistics and analyses to examine the change in the spatial inequality of FDI among regions and among prefectural cities, and uses regression models and spatial regime analyses to investigate factors influencing the inequality from 1990 to 2010. The spatial diffusion of FDI clusters from the eastern/coastal region to the interior shows the trend of FDI convergence among regions. However, increasing numbers of FDI clusters and hot spots show the increasing divergence among cities within three regions. Agglomeration effects have replaced institutional factors to become one of the most significant factors influencing the FDI inequality among cities. Additionally, special economic zones, coastal open cities, provincial capital cities, and development zones lost their advantages in FDI as more reforms set in. The spatial regime analyses further indicate the significance of market size in FDI in prefecture-level cities and the significance of agglomeration economies in FDI in capitals and municipalities.  相似文献   

遥感影像亚像素快速配准方法     

周靖鸿  朱建军  周璀  樊东昊 《测绘工程》2016,25(7):71-77

针对经典亚像素配准算法运算效率不高的情况,提出一种快速亚像素配准方法。在原有傅里叶变换相位相关方法与矩阵乘法离散傅里叶变换方法的基础上,利用有效子图代替原图进行图像亚像素配准。有效子图是通过二维小波分解高频分量的能量总和大小来选取,再对有效子图进行相位相关像素级定位与矩阵乘法傅里叶变换亚像素定位。改进方法不但继承矩阵乘法离散傅里叶变换亚像素高精度配准的优良性能,而且选用有效子图替代原图进行配准其速度可大大提高,对海量数据的遥感影像更显优势。经模拟试验与工程实例,综合分析该方法的配准精度与配准速度,证明改进方法较经典亚像素配准算法效率更高,更适合用于实际遥感影像的高精度配准。  相似文献   

Simulating Aerosol Optical Depth and Direct Radiative Effects over the Tibetan Plateau with a High-Resolution CAS FGOALS-f3 Model     

Min ZHAO  Tie DAI  Hao WANG  Qing BAO  Yimin LIU  Hua ZHANG  Guangyu SHI 《大气科学进展》2022,39(12):2137-2155

Current global climate models cannot resolve the complex topography over the Tibetan Plateau (TP) due to their coarse resolution. This study investigates the impacts of horizontal resolution on simulating aerosol and its direct radiative effect (DRE) over the TP by applying two horizontal resolutions of about 100 km and 25 km to the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere Land System (CAS FGOALS-f3) over a 10-year period. Compared to the AErosol RObotic NETwork observations, a high-resolution model (HRM) can better reproduce the spatial distribution and seasonal cycles of aerosol optical depth (AOD) compared to a low-resolution model (LRM). The HRM bias and RMSE of AOD decreased by 0.08 and 0.12, and the correlation coefficient increased by 0.22 compared to the LRM. An LRM is not sufficient to reproduce the aerosol variations associated with fine-scale topographic forcing, such as in the eastern marginal region of the TP. The difference between hydrophilic aerosols in an HRM and LRM is caused by the divergence of the simulated relative humidity (RH). More reasonable distributions and variations of RH are conducive to simulating hydrophilic aerosols. An increase of the 10-m wind speed in winter by an HRM leads to increased dust emissions. The simulated aerosol DREs at the top of the atmosphere (TOA) and at the surface by the HRM are –0.76 W m^–2 and –8.72 W m^–2 over the TP, respectively. Both resolution models can capture the key feature that dust TOA DRE transitions from positive in spring to negative in the other seasons.  相似文献