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针对数控火焰切割机自动调高系统的特点和要求,采用遗传算法对其位置调节器PID参数进行全局优化辨识,有效地解决了直流伺服电机的控制精度和快速性的问题.仿真结果表明,与传统的参数辨识法相比,遗传算法参数寻优使自动调高系统的动态性能大幅提高,具有很强的鲁棒性. 相似文献
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Little attention has been paid thus far to the experiences of developed countries in adapting to climate change. This article addresses this research gap by providing an assessment of broad trends in progress on planning and implementing adaptation in developed countries. Primary inputs are the National Communications (NCs) by these countries to the United Nations Framework Convention on Climate Change (UNFCCC), although the article also discusses illustrative examples of recent adaptation activities that have not been covered in the NCs. NCs reflect ‘whole government’ perspectives and follow a standardized reporting format, which facilitates cross-national comparisons. The analysis shows that impacts and adaptation receive limited attention within NCs. The discussion on impacts and adaptation has typically been dominated by climate scenarios and impacts analysis, while the discussion on adaptation is often limited to the identification of generic options. There are signs of recent progress, however, in the Third and especially the Fourth NCs, in which a growing number of developed countries report on establishing frameworks for adaptation and on efforts to implement adaptation measures that take future climate into account. Although an encouraging sign, it is still too early to assess the eventual impact of such measures. 相似文献
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In this study, an evaluation of fuzzy-based classifiers for specific crop identification using multi-spectral temporal data spanning over one growing season has been carried out. The temporal data sets have been georeferenced with 0.3 pixel rms error. Temporal information of cotton crop has been incorporated through the following five indices: simple ratio (SR), normalized difference vegetation index (NDVI), transformed normalized difference vegetation index (TNDVI), soil-adjusted vegetation index (SAVI) and triangular vegetation index (TVI), to study the effect of indices on classified output. For this purpose, a comparative study between two fuzzy-based soft classification approaches, possibilistic c-means (PCM) and noise classifier (NC), was undertaken. In this study, advanced wide field sensor (AWiFS) data for soft classification and linear imaging self scanner sensor (LISS III) data for soft testing purpose from Resourcesat-1 (IRS-P6) satellite were used. It has been observed that NC fuzzy classifier using TNDVI temporal index – dataset 2, which comprises four temporal images performs better than PCM classifier giving highest fuzzy overall accuracy of 96.03%. 相似文献
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Thirty-six Silurian core and cuttings samples and 10 crude oil samples from Ordovician reservoirs in the NC115 Concession, Murzuq Basin, southwest Libya were studied by organic geochemical methods to determine source rock organic facies, conditions of deposition, thermal maturity and genetic relationships. The Lower Silurian Hot Shale at the base of the Tanezzuft Formation is a high-quality oil/gas-prone source rock that is currently within the early oil maturity window. The overall average TOC content of the Hot Shale is 7.2 wt% with a maximum recorded value of 20.9 wt%. By contrast, the overlying deposits of the Tanezzuft Formation have an average TOC of 0.6 wt% and a maximum value of 1.1 wt%. The organic matter in the Hot Shale consists predominantly of mixed algal and terrigenous Type-II/III kerogen, whereas the rest of the formation is dominated by terrigenous Type-III organic matter with some Type II/III kerogen. Oils from the A-, B- and H-oil fields in the NC115 Concession were almost certainly derived from marine shale source rocks that contained mixed algal and terrigenous organic input reflecting deposition under suboxic to anoxic conditions. The oils are light and sweet, and despite being similar, were almost certainly derived from different facies and maturation levels within mature source rocks. The B-oils were generated from slightly less mature source rocks than the others. Based on hierarchical cluster analysis (HCA), principal component analysis (PCA), selected source-related biomarkers and stable carbon isotope ratios, the NC115 oils can be divided into two genetic families: Family-I oils from Ordovician Mamuniyat reservoirs were probably derived from older Palaeozoic source rocks, whereas Family-II oils from Ordovician Mamuniyat–Hawaz reservoirs were probably charged from a younger Palaeozoic source of relatively high maturity. A third family appears to be a mixture of the two, but is most similar to Family-II oils. These oil families were derived from one proven mature source rock, the Early Silurian, Rhuddanian Hot Shale. There is a good correlation between the Family-II and -III oils and the Hot Shale based on carbon isotope compositions. Saturated and aromatic maturity parameters indicate that these oils were generated from a source rock of considerably higher maturity than the examined rock samples. The results imply that the oils originated from more mature source rocks outside the NC115 Concession and migrated to their current positions after generation. 相似文献
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西北地区可持续发展的问题与对策* 总被引：14，自引：1，他引：14
可持续发展作为我国的三大基本国策之一,对今后20年～30年西北地区的大规模开发具有重要的指导意义。文中对影响西北地区跨世纪可持续发展的重大问题,如经济的持续快速增长,产业结构的调整优化,基础设施的建设与改善投资环境,重点开发地区的选择,水资源的合理利用与生态环境保护作了深入分析,并提出相应对策。 相似文献
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Temporal MODIS data for identification of wheat crop using noise clustering soft classification approach 总被引：1，自引：0，他引：1
In this study, temporal MODIS-Terra MOD13Q1 data have been used for identification of wheat crop uniquely, using the noise clustering (NC) soft classification approach. This research also optimises the selection of date combination and vegetation index for classification of wheat crop. First, a separability analysis is used to optimise the date combination for each case of number of dates and vegetation index. Then, these scenes have undergone for NC soft classification. The resolution parameter (δ) was optimised for the NC classifier and found to be a value of 1.6 × 104 for wheat crop identification. Classified outputs were analysed by receiver operating characteristics (ROC) analysis for sub-pixel detection. Highest area under the ROC curve was found for soil-adjusted vegetation index corresponding to the three different phenological stages data sets. From this study, the data sets corresponding to the Sowing, Flowering and Maturity phenological stages of wheat crop were found more suitable to identify it uniquely. 相似文献
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张洪喜 《测绘与空间地理信息》2015,(5):160-162
地理国情普查是一项覆盖全国、长期持续的生产任务.国情软件在整个国情生产中起到重要作用,本文通过对地理国情信息提取软件Geoway For NC的应用角度出发,分析了地理国情普查的作业流程,阐述了国情要素的提取方法,总结了利用该软件的生产经验,希望对利用相关软件进行国情生产有所帮助. 相似文献
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褐藻寡糖激发子诱导烟草抗低温作用研究 总被引：3，自引：0，他引：3
研究褐藻寡糖在低温下对烟草的保护作用,探讨褐藻寡糖作用机理,将褐藻寡糖溶液均匀喷施到烟草叶面后置于(4±1)℃下进行低温胁迫,间隔不同时间检测相关指标.研究发现,浓度是影响褐藻寡糖抗冻性能的重要因素.0.05%,0.20%和0.30%褐藻寡糖具有诱导激发因子作用,能够诱导烟草CAT、SOD和POD活力提高,清除体内产生的氧自由基,保护细胞膜和叶绿素结构,减少烟草叶片损伤,提高烟草耐低温能力,其中以0.20%褐藻寡糖诱导效果最好;0.10%褐藻寡糖具有抗冻保护剂作用,在24 h内烟草各项指标均没有明显变化,可保护细胞免受低温伤害,但48 h时冻伤指标增强,其保护作用减弱或者消失;高浓度1.00%褐藻寡糖具有毒副作用,在烟草细胞表面形成较强渗透势,胞内物质外渗严重,烟草细胞结构受到破坏,加速低温下烟草叶片损伤. 相似文献
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The 8 October 2005 earthquake caused widespread destruction in both the state of Jammu and Kashmir of India and Northern Pakistan. Due to poor accessibility in the hazardous and difficult mountainous terrain, a proper and comprehensive ground-based survey was not possible. However, with the help of remote sensing data and its analysis techniques, it is feasible to undertake both earthquake-related damage identification and assessment. This study attempts to document and identify built-up damaged (BD) areas using spectral indices taking temporal multispectral images from IRS-P6 LISS-IV. Five spectral indices have been used to identify BD areas using supervised possibilistic c-means (PCM) and noise cluster (NC) classifiers, to analyse the satellite data. The result indicates that Class Based Sensor Independent (CBSI) based Transformed Normalized Difference Vegetation Index (TNDVI) temporal indices provide the best results for identifying BD areas, while Simple Ratio (SR) index gives the best results for built-up undamaged area identification. Further, it observed that PCM classifier performed better in comparison to NC classifier. 相似文献