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51.
The increasing global coverage of high resolution/large-scale digital elevation data has allowed the study of geomorphological form to receive renewed attention by providing accessible datasets for the characterisation and quantification of land surfaces. Digital elevation models (DEMs) provide quantitative elevation data, but it is the characterisation and extraction of geomorphologically significant measures (morphometric indices) from these raw data that form more informative and useful datasets. Common to many geographical measures, morphometric measures derived from DEMs are dependent on the scale of observation. This paper reports results of employing a fuzzy c-means classification for a sample DEM from Snowdonia, Wales, with a number of morphometric measures at different resolutions as input, and morphometric classification of landforms at each resolution as output. The classifications reveal that different landscape components or morphometric classes are important at different resolutions, and that morphometric classes exhibit resolution dependency in their geographical extents. Examination of the scale dependency and behaviour of morphometric classifications of landforms at different resolutions provides a fuller and more holistic view of the classes present than a single-scale analysis. 相似文献
52.
本文以面向敏捷企业的智能制造执行系统(I-MES)为研究对象,采用多Agent技术作为系统的实现形式,对系统的多Agent组织结构、系统中多Agent间的通信和协作机制以及多Agent的基于事件和周期的动态调度策略等理论问题和关键技术进行了研究,针对可集成制造执行系统中最常见的资源冲突问题,提出了一种基于多Agent合作的冲突消解模型;在此基础上针对敏捷环境下传统的制造执行系统的不足,以烟草企业这类流程性工艺企业为背景,基于多代理技术,构建了一个基于多代理具有开放性、集成性、动态性、敏捷性和可互操作的敏捷制造智能执行系统, 相似文献
53.
Theoretical considerations on imaging of micron size electron beam with optical transition radiation
Dao Xiang Wen-Hui Huang 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2007,570(3):357-364
Optical transition radiation (OTR) has been widely used to image electron beam profile. In this paper, we systematically investigated the issues related to imaging of electron beam with OTR. It is found that the point-spread function (PSF) largely depends on the acceptance angle of the lens and is only very weakly dependent on beam energy and the distance from the OTR target to the lens. This excludes the potential obstacles to imaging of high-energy electron beam for which, the photons are emitted in a relatively small cone and the far field condition is hard to fulfill. The image of a whole beam is found by convoluting the real beam distribution with the PSF. It is shown that for micron size beam, the image formed with OTR largely deviates from the real beam distribution. And the real beam distribution could be restored from deconvoluting the image with the PSF. The effectiveness of the restoration is demonstrated, which opens up the possibility of measuring micron size beam profile with OTR. 相似文献
54.
55.
在低信噪比地震资料处理中,随机噪声的消除是至关重要的。基于方向信号测度的多级中值滤波和中值约束下的矢量分解去噪等中值滤波技术,对江汉地区的低信噪比资料进行了处理,结果表明,随机噪声得到了有效的压制,信噪比得到了明显的提高。 相似文献
56.
张耀辉 《长沙通信职业技术学院学报》2007,6(3):46-49
文章首先对ARP协议的原理和ARP地址欺骗攻击的原理进行了分析,然后讲述了如何检查和处理ARP欺骗病毒的方法,最后提出了如何防范ARP攻击的各种措施. 相似文献
57.
《Mechatronics》2014,24(6):605-618
The resolution is a critical performance metric of precision mechatronic systems such as nanopositioners and atomic force microscopes. However, there is not presently a strict definition for the measurement or reporting of this parameter. This article defines resolution as the smallest distance between two non-overlapping position commands. Methods are presented for simulating and predicting resolution in both the time and frequency domains. In order to simplify resolution measurement, a new technique is proposed which allows the resolution to be estimated from a measurement of the closed-loop actuator voltage. Simulation and experimental results demonstrate the proposed techniques. The paper concludes by comparing the resolution benefits of new control schemes over standard output feedback techniques. 相似文献
58.
W. Bibel 《Journal of Automated Reasoning》1990,6(3):287-297
Quadratic proofs of pigeonhole formulas are presented using connection method proof techniques. The interest of this result derives from the fact that for this class of formulas exponential lower bounds are known for the length of resolution refutations. 相似文献
59.
Soo Ho Kim Hoon Park Seung Hyun Jee Ho Sang Ahn Dong-Joo Kim Ji Won Choi Seok Jin Yoon Young Soo Yoon 《Korean Journal of Chemical Engineering》2009,26(2):485-488
A two-step calcination synthesis, considering the potential for mass production, of lithium titanium oxide powder was carried
out to fabricate a single Li4Ti5O12 phase, which is useful for anode electrode material of Li-based rechargeable battery as well as an electrode for supercapacitor.
The final composition is controlled by adding more TiO2 powder into powder gained at one calcination process during the two calcination process. We investigated the influence of
excess TiO2 on the structural characteristics of lithium titanium oxide synthesized by the two-step calcination method. X-ray diffraction
(XRD) and Fourier transform infrared spectroscopy (FT-IR) measurements showed that the as-synthesized powder had a spinel
crystal structure as well as A composition of 4: 5: 12. In addition, a high resolution transmission electron microscopy (HRTEM)
analysis revealed that the fabricated powder exhibited a single crystalline phase formation. These results indicated that
the powder synthesized in the one-step calcination process showed coexistence crystalline phases, which are the Li4Ti5O12 and Li2.39Ti3.4O8 phase. However, in the two-step calcination process, the powder synthesized showed the single crystalline Li4Ti5O12 phase. A very uniform grain size of the as-synthesized powder was shown in a field emission scanning electron microscopy
(FESEM). These results suggested that the two-step calcination process can be used for synthesis of single crystalline Li4Ti5O12 powder with uniform grain shape and provide motivation to pursue mass production of lithium titanium based oxide powder for
bulk type batteries. 相似文献
60.
对风云三号(FY-3)中分辨率光谱成像仪(MERSI)的黑体进行了在轨太阳污染模拟,以掌握在轨太阳污染对面源黑体的影响,同时研究了抑制太阳污染的措施。模拟了FY-3卫星轨道及全轨道周期内太阳光的入射角,使用Tracepro软件建立了太阳污染模拟的模型,利用太阳光入射与MERSI的相对位置对太阳污染进行仿真,分析了污染随光谱成像仪扫描镜旋转和卫星飞行位置的变化。最后,根据分析结果设计了太阳污染抑制措施,并对抑制效果进行了仿真验证。结果表明:在扫描镜附近区域设置遮光板,有效地抑制了太阳光的污染,使辐射量级小于0.1 W,整个太阳污染功率下降了97%以上,对黑体有良好的保护效果。另外,提出的方法提高了面源黑体温度的均匀性和稳定性,保证了红外通道星上定标精度。 相似文献