基于无人机航摄技术在土地整治项目中的应用研究

针对传统土地整治项目施工监管、后期监测效率不高的问题,本文通过低空无人机航摄和PhotoScan软件后期处理,对比生成的正射影像图和Google earth卫星图的分辨率和位置,发现该影像图能精准、高效的表征项目区影像数据变化,从而得到一种可用于土地整治项目各阶段动态观测的简单、快捷方法。     

Comparison of Seven Digital Cameras for Digitizing Radiographs

The purpose of this study was to evaluate seven digital cameras for their ability to adequately capture quality radiographic images and their relative cost effectiveness. Radiographs of line pair (LP) phantoms (ranging from 0.6 to 16.6 LP/mm) and a 20-step contrast phantom were photographed at a near distance of 30.0 cm and a far distance (determined for each camera) at which a full 14 x 17 in film filled the viewfinder. Of the seven cameras tested, the Canon EOS-D30 consistently performed the best in LP/mm resolved (7.7 at close distance, 1.4 at far distance) and in contrast latitude (all 20 steps at both close and far distances). The Canon EOS-D30, determined to be the best camera used in this study for photographing radiographic images, is also the most expensive camera that was used. Two cameras, the Nikon Coolpix 995 and the Sony DSC-F707, were very close to the Canon in performance at considerably less cost. Certain inexpensive cameras may not be acceptable choices for teleradiology.     

A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators

Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle.     

由熊猫烧香病毒看图书馆网络安全

图书馆网络的安全涉及到计算机系统的硬件与软件的方方面面,针对新型病毒的产生,图书馆网络安全也应当适应新形势,采取必要的安全保护策略,合理构建网络安全系统。     

高校数字图书馆著作权合理使用的相关问题

数字技术和网络环境改变了高校图书馆的传统服务模式,同时也给著作权合理使用制度带来新的挑战。探讨在网络环境下,如何正确对待及适应国家乃至国际上对著作权的相关法律规定。完善著作权在高棱数字图书馆的合理使用。     

海量信息存储在本馆的应用浅谈

就数字图书馆建设过程中的海量存储问题,对目前IT界的海量存储技术进行了简要介绍,并对该馆建设海量存储系统的情况做了详细介绍。     

基于温岭市二类调查的航空影像正射纠正技术研究

航空影像是二类调查的重要基础资料,但航空影像因地形等因素影响而产生畸变,使用前需要消除畸变进行正射纠正。本研究根据UltraCamX数字航摄相机的信息,在LPS工程中设置对应的参数,读入数据自带的外方位元素,直接对空三计算结果进行设定,对正射影像的定位精度以地形图为参照进行分析。结果表明：应用LPS就可以完成对数字航摄影像正射纠正,处理后的影像的匹配性较好,定位精度较高,效果较理想;通过检查点提取地形图和影像的对应坐标进行误差计算,平均总误差仅为1.249 m,可以满足温岭市森林资源二类调查的需要;该方法解决了航空影像数据量大、数量多、处理时间长、DEM使用等难题,对实际生产具有重要意义。     

基于Granger因果检验的农村金融发展与经济效率提升研究

以协整检验理论为基础,采用Granger因果检验法,选取金融相关比率（FIR）、金融效率水平（LFE）、金融发展水平（LFD）等为度量农村金融发展的指标,采集1979～2007年的农村贷款余额（RLB）、存款余额（RDB）、农村总产出（TRO）、固定资产投资（FAI）、金融相关比率（FIR）、经济效率（EE）、金融效率（LFE）和金融发展水平（LFD）数据,用图示法直观的表达了相关指标的历史轨迹及发展趋势,并用Granger因果检验法实证检验了1979～2007年我国农村金融发展水平与农村经济效率之间的关系。结果表明,农村金融发展水平对农村经济增长作用显著,而农村经济增长对农村金融发展却没有显著影响;农村金融发展对农村经济效率提升作用不显著。由此得出结论：虽然农村金融发展对农村经济的发展具有一定贡献,但这种贡献仅仅体现在总量而非效率方面。为此,应进一步强化金融发展对经济增长效率的提升作用,逐步构建农村金融与经济发展的良性循环体系。