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1.
Information on river stages can be transmitted to relevant management offices over a network by using an automatic stage gauge so that management offices can effectively evaluate whether a river stage is exceeding the warning line and take action if necessary. However, current river stage measurement methods can present this information only in data form because the methods cannot simultaneously obtain images such as the rising or overflow of the river stage. In addition, the stage gauge can fail or be washed away when the river stage is high. To solve these problems, this research evaluates a novel measurement method involving a video surveillance system that exhibits features such as easy installation, low maintenance cost, and low failure possibility. Through on-site image recording, this measurement method involves using image identification technology to read water level figures automatically. This method offers instant river stage figures and on-site video so that disaster prevention measures can be implemented accordingly. The results of a dynamic water flow test conducted in an indoor experimental channel indicated that all of the average absolute error levels of river stage identification were less than ±1.2 %, meaning that the image identification technology could achieve identification results at any flow level. By contrast, the findings of a rainfall simulation experiment suggest that the average absolute error of river stage identification was less than ±2.5 %, meaning that the measurement technology and method used in this research are useful and feasible at various rainfall intensities.  相似文献   

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王任一  梅廉夫 《沉积学报》2008,26(6):947-956
首次提出了利用测井曲线不同形态识别沉积微相方法(算法)必须要满足三个前提条件,即平移和尺度缩放的不变性以及旋转可变性的认识,并提出了一种满足这三个前提条件的利用测井曲线形态识别沉积微相的新方法。主要通过求取不同测井曲线形态的边界方向概率密度后,再对其进行小波变换,可用少数几个对其方向概率密度可以近视重构的低频小波描述子进行沉积微相识别,同时建立了不同沉积微相小波描述子识别模式。对反映不同沉积微相的测井曲线形态方向概率密度函数进行小波分析,使沉积微相信息从高维特征空间被映射到由少数几个低频小波描述子组成低维特征向量空间,使不同沉积微相间差异信息得到放大突出。该方法不仅使利用测井曲线形态对沉积微相识别的这一较复杂问题,简化为对少数几个低频小波描述子进行判断的简单问题,而且还可利用这些小波描述子对其进行一定程度上沉积学分析。  相似文献   

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The microbial communities in a two-stage anaerobic digestion process treating olive mill “solid” residues were studied by molecular identification techniques. The microbial species identification in the hydrolytic-acidogenic step and in the methanogenic step was carried out by polymerase chain reaction amplification of 16S ribosomal RNA genes, denaturing gradient gel electrophoresis, cloning, and sequencing. This study revealed that Firmicutes (from 31.1 to 61.1 %, average 42.1 %) mainly represented by Clostridiales, and the Chloroflexi (from 29.4 to 53.3 %, average 47.35 %) were the most abundant species for the hydrolytic-acidogenic reactor. Other microorganisms such as Gamma-Proteobacteria (Pseudomonas species as the major representative; from 3.9 to 9.7 %; average 5.7 %), Actinobacteria (from 1.0 to 10.2 %; average 4.6 %) and Bacteroidetes (from 1.1 to 3.1 %; average 1.7 %) were also detected. The methanogenic communities detected in the methanogenic reactor were mainly represented by members of the obligate acetotrophic methanogenic genus Methanosaeta. Methanosaeta was the crucial Archaea to obtain a high methane yield in the methanogenic stage.  相似文献   

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Physiographic factors along with edaphic conditions play a crucial role in establishment of plant species throughout a region. Identification of the most effective factors is of high importance in sustainable management of a forest ecosystem. This study aims to investigate the relationships between understory vegetation and some environmental factors in natural forest ecosystems. This study has been carried out among the Fagetum orientalis communities of Ramsar Region, located in the north of Iran. For this purpose, 105 releves were sampled by a randomized-systematic method throughout the study area, using the Braun-Blanquet scale. Physiographic parameters such as elevation, as well as slope and orientation were measured. By identification of the herb-layer vegetation contained in each sampling, vegetation composition and cover abundance of species were separately identified. Then, the aforementioned properties of soil were entirely measured in the taken samples. Cluster analysis and detrended correspondence analysis have been applied to classify the site. Moreover, in order to determine the relation between species composition and environmental factors, canonical correspondence analysis was used. Results showed a significant relation between distribution of plant types and environmental factors. Eventually, environmental factors including slope, orientation, silt percent, pH, organic matter and soluble phosphorous were among the most effective factors in establishment of Hedera pastuchowii, Solanum kieseritzkii, Oplismenus undulatifolius, Sedum stoloniferum, Rubus hyrcanus and Saxifraga cymbalaria species.  相似文献   

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曹蒙  王志章  李冰涛  曲康  裴升杰  贾小玉 《地质论评》2023,69(2):2023020001-2023020001
在油气勘探、评价及开发中,岩性识别和薄片鉴定是十分重要的基础工作,准确的薄片识别结果可以为勘探和开发提供可靠的依据。传统的人工判定方法或实验室分析方法具有主观性强、效率低、自动化程度低等问题。目前基于内容的智能图像识别技术在准确性和具体应用方面还面临着许多难题。论文基于国内外相关研究成果与油气勘探与开发中岩芯薄片图像的特点及要求,设计并研制成功薄片图像自动识别系统和薄片智能鉴定系统。利用图像梯度分布和色彩分析进行火成岩岩石薄片智能分类,对所有像素进行类别划分进而得到整体的鉴定结果,实现了省时、高效、高精度的薄片智能鉴定成果。  相似文献   

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在油气勘探、评价及开发中,岩性识别和薄片鉴定是十分重要的基础工作,准确的薄片识别结果可以为勘探和开发提供可靠的依据。传统的人工判定方法或实验室分析方法具有主观性强、效率低、自动化程度低等问题。目前基于内容的智能图像识别技术在准确性和具体应用方面还面临着许多难题。论文基于国内外相关研究成果与油气勘探与开发中岩芯薄片图像的特点及要求,设计并研制成功薄片图像自动识别系统和薄片智能鉴定系统。利用图像梯度分布和色彩分析进行火成岩岩石薄片智能分类,对所有像素进行类别划分进而得到整体的鉴定结果,实现了省时、高效、高精度的薄片智能鉴定成果。  相似文献   

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石崇  白金州  于士彦  王伟 《岩土力学》2016,37(10):2780-2786
岩土细观特征的识别与分析是岩土力学研究的重要内容。基于傅里叶变换原理,将任意岩土颗粒的二维轮廓变换为傅里叶描述符与相位进行分析,建立了基于复数傅里叶分析的细观特征表征与重构方法。通过两组不同颗粒的傅里叶细观特征统计,研究了不同阶傅里叶描述符与细观特征参量的对应关系。结果表明:-12~0及16~20阶对应的傅里叶描述符决定颗粒的形状;-23~-11及1~15阶对应的傅里叶描述符与颗粒粗糙度密切联系;傅里叶描述符曲线峰值与颗粒的粒径显著线性相关;高阶傅里叶系数与阶数近似呈对数线性关系,低阶系数则由不同颗粒形状决定。采用建立的傅里叶描述符对应关系进行颗粒相似重构研究,发现重构颗粒的外轮廓及傅里叶统计参量与实际颗粒十分接近,且反映颗粒的粗糙度、纹理等细部特征,其成果可用于大量岩土颗粒与力学特性的相关性研究。  相似文献   

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Nine cores were taken from a damp depression at Dingé, Ille-et-Vilaine, northwest France. Analyses of the pollen, plant macrofossil and Coleoptera remains preserved in the same organic samples of two profiles suggest a temperate vegetation characterised by a mixed deciduous forest with mesophilous taxa (Carpinus, Fagus, Quercus) followed by a coniferous forest with Pinus and Picea. The determination of plant taxa to species was made either directly through the identification of plant macrofossil remains and pollen or indirectly through the identification of phytophagous Coleoptera specifically related to certain plants. Stratigraphical information derived from pollen, plant macrofossil and insect data indicates that this sequence may be correlated with a temperate episode older than the Eemian and younger than the Holsteinian, possibly the Bouchet 2 (Oxygen Isotope Stage 7c) or Bouchet 3 (Oxygen Isotope Stage 7a) temperate periods or the Landos Interglacial (Oxygen Isotope Stage 9 pro parte). © 1997 John Wiley & Sons, Ltd.  相似文献   

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Low-lying coastal ecosystems along the northern Gulf of Mexico are already experiencing the effects of elevated salinity from sea-level rise and are predicted to face extreme events such as extended saltwater inundation, intense Atlantic hurricanes, and episodic drought. The ability of coastal plant communities to survive stresses from these events depends largely on how these communities respond to the stresses. Our understanding of how plant communities dominated by native vs. invasive plants respond to extreme events is limited. Utilizing controlled greenhouse experiments, we assessed the responses of floating aquatic macrophyte communities, dominated by native or invasive plants, of the coastal floodplains, Louisiana, USA, to a gradient of chronic salinity, mimicking sea-level rise; a gradient of acute salinity, mimicking hurricane storm surges; and a gradient of desiccation stress, mimicking episodic drought. We found that salinity and desiccation stress effects on plant communities depended on the degree of plant invasion; plant community cover decreased precipitously as severity of stress increased. Specifically, extreme salinity led to a decrease in plant cover of >?90% when communities were dominated by invasive plants, whereas increased desiccation stress led to decreased plant cover of 100% when communities were dominated by native species. At low to moderate salinity, invasive dominated plant communities performed better than native dominated. These responses to salinity and desiccation stress may drive large-scale shifts in plant community structure, including loss of species. Our results underscore the importance of evaluating plant community responses to environmental extremes to determine the potential for future effects on dynamics and functioning of low-lying coastal floodplain ecosystems experiencing effects of climate change.  相似文献   

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利用遥感数据和实测不同岩土类型波谱测试数据,以实测不同土体反射光谱数据为基础,通过对遥感数据进行图像增强处理,对不同沉积环境、不同粒级组成的松散土体类型进行识别。研究发现,ASTER数据721波段组合能够有效识别不同土体类型,在凸显不同土体类别的效果最好;ASTER数据的平方根拉伸及标准分段拉伸对不同土体类型的区分效果最好;通过对遥感数据进行主成分变换,发现遥感数据图像信息量得到有效集中,增强了图像的层次感,能够有效增强图像信息。  相似文献   

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http://www.sciencedirect.com/science/article/pii/S1674987114001388   总被引:1,自引:0,他引:1  
Proper quality planning of limestone raw materials is an essential job of maintaining desired feed in cement plant. Rock-type identification is an integrated part of quality planning for limestone mine. In this paper, a computer vision-based rock-type classification algorithm is proposed for fast and reliable identification without human intervention. A laboratory scale vision-based model was developed using probabilistic neural network(PNN) where color histogram features are used as input. The color image histogram-based features that include weighted mean, skewness and kurtosis features are extracted for all three color space red, green, and blue. A total nine features are used as input for the PNN classification model. The smoothing parameter for PNN model is selected judicially to develop an optimal or close to the optimum classification model. The developed PPN is validated using the test data set and results reveal that the proposed vision-based model can perform satisfactorily for classifying limestone rocktypes. Overall the error of mis-classification is below 6%. When compared with other three classification algorithms, it is observed that the proposed method performs substantially better than all three classification algorithms.  相似文献   

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基于煤岩孔隙系统多尺度结构特征对深入认识多尺度流体运移机制的重要性,提出了基于图像描述的煤岩CT图像孔隙结构的多尺度精细描述方法。采用了图像的多策略分割技术提取目标,利用Freeman链码对目标的边界进行表达,研究了由形态学、统计矩、链码、计盒维数构造目标之间的关系、目标占有区域与边界的图像描绘子、以及分形描绘子;综合运用上述方法对煤岩CT图像中的大尺度宏观裂纹目标、小尺度细观裂隙目标进行了识别。结果表明,宏观裂纹可由灰度阈值法实现目标提取;小尺度细观裂隙需采用较复杂的分割策略,如基于索贝尔梯度算子的分水岭变换;进一步应用链码表达、图像描绘子和分形描绘子,实现了煤岩孔隙结构在欧氏空间与分形空间的多尺度精确描述。  相似文献   

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This work illustrates the effectiveness of hyperspectal image spectroscopy and lab spectroscopy in identification techniques of minerals in alteration zone of ore body. The adopted procedure involves testing of Hyperion image spectra, their processing for noise, spectral matching and spectral similarity measurement with selected library spectra. Average weighted spectral similarity; visual and statistical matching techniques were used to select end-members from image spectra. Minimum noise fraction and pixel purity index technique were used to retrieve end-member spectra from hyperion image. Hyperspectral image like hyperion has the capability to deliver laboratory standard spectroscopic result. This paper illustrates the capability of hyperion image spectra in copper ore identification and mapping of chalcopyrite outcrop. A systematic approach has been made in this paper. This approach describes how image end member spectra and laboratory spectra can be co-related to fetch accurate spectral form of chalcopyrite ores. Thus, statistical and graphical comparison has been carried out between image derived end member spectra and laboratory spectra of chalcopyrite for better accuracy. The visual measurements is satisfactory, R = 0.973 for fine and 0.976 for medium grained chalcopyrite ore. Excellent statistical significance levels (90–97%) are found while comparing these spectra. There are many success stories of sub-pixel and N-dimensional feature space methods to separate the hydrothermal alteration zones from iron oxide mixed ore bodies. Thus, unmixing methods are very useful for mapping of most dominating mineral parts of a pixel from hyperspectral images which have coarse spatial resolution. Finally, mapping of mineralized zone has been achieved through sub-pixel based classifiers like spectral angle mapper (SAM), constrained energy minimization (CEM) and adaptive coherence estimator (ACE) techniques.  相似文献   

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在高光谱遥感找矿应用中,从影像上提取的蚀变信息经常包含了很多对找矿无用的信息。为了避免这些无用信息,本研究选取植被覆盖的云南普朗斑岩铜矿区作为研究区,使用该区高光谱遥感数据分别提取蚀变岩和蚀变矿物的信息,分析它们对找矿的有用性。提取蚀变矿物信息使用的是从影像上提取的矿物端元参考光谱,光谱匹配采用的是光谱角方法;提取蚀变岩信息使用的是野外蚀变岩参考光谱,光谱匹配不仅考虑光谱的整体形态,而且考虑吸收谷位置形态。在蚀变岩识别图上,4个典型蚀变岩点的野外验证表明:识别结果与实地地物基本一致。但是,在蚀变矿物信息图中,这4个圈定点无任何信息。这表明:这些点的蚀变岩信息较其表面蚀变矿物信息更丰富,因而能被有效提取出。通过比较蚀变岩、蚀变矿物的信息分布图,发现:一些粘土矿物(比如硬石膏和高岭石)的大量信息分布在沉积岩区,因而可能是假的蚀变信息。这表明:通过蚀变岩光谱获取的蚀变信息比通过蚀变矿物光谱获取的蚀变信息更可靠。在蚀变岩信息提取中,比较吸收谷位置识别前后的结果表明:考虑光谱整体和局部形态比仅考虑整体形态的识别结果具有更高的可靠性。  相似文献   

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Tidal freshwater marshes around the world face an uncertain future with increasing water levels, salinity intrusion, and temperature and precipitation shifts associated with climate change. Due to the characteristic abundance of both annual and perennial species in these habitats, even small increases in early growing season water levels may reduce seed germination, seedling establishment, and late-season plant cover, decreasing overall species abundance and productivity. This study looks at the distribution of tidal freshwater marsh plant species at Jug Bay, Patuxent River (Chesapeake Bay, USA), with respect to intertidal elevation, and the relationship between inundation early in the growing season and peak plant cover to better understand the potential impacts and marsh responses to increased inundation. Results show that 62% of marsh plant species are distributed at elevations around mean high water and are characterized by narrow elevation ranges in contrast with species growing at lower elevations. In addition, the frequency and duration of inundation and water depth to which the marsh was exposed to, prior to the growing season (March 15–May 15), negatively affected peak plant cover (measured in end-June to mid-July) after a threshold value was reached. For example, 36 and 55% decreases in peak plant cover were observed after duration of inundation threshold values of 25 and 36% was reached for annual and perennial species, respectively. Overall, this study suggests that plant communities of tidal freshwater marshes are sensitive to even small systematic changes in inundation, which may affect species abundance and richness as well as overall wetland resiliency to climate change.  相似文献   

19.
Terrestrial plants and insects currently account for the majority of the Earth's biodiversity, and approximately half of insect species are herbivores. Thus, insects and plants share ancient associations that date back more than 400 Myr. However, investigations of their past interactions are at the preliminary stages in Western Europe. Herein, we present the first results of our study of various feeding damage based on a dataset of nearly 3500 examined plant specimens from the Lower Miocene of the Lagerst?tte Bílina Mine in the Most Basin, Czech Republic. This site provides a unique view of the Neogene freshwater ecosystems. It has long been studied by scientists working in different branches of sedimentology, paleobotany, and paleozoology. The fossils are preserved in three characteristic horizons overlaying the coal seam (Clayey Superseam Horizon, Delta Sandy Horizon, and Lake Clayey Horizon), reflecting paleoenvironmental changes in a short time period of development. The trace fossils are classified as functional feeding groups or “guilds”, without searching for a direct cause or a recent analog host relation. Approximately 23% of specimens of dicotyledonous plant leaves were found to be damaged and associated with some leaf “morphotypes”. Deciduous plant–host taxa, and those with a chartaceous texture typical of riparian habitats, were frequently damaged, such as Populus, recorded with two species Populus zaddachii and Populus populina (57.9% and 31% herbivory levels, respectively), followed by Acer, Alnus, and Carya, averaging almost 30% of damaged leaves/leaflets. There has been evidence of 60 damage types (DT) representing all functional feeding groups recorded at the Bílina Mine, including 12 types of leaf mines and 16 gall-type DT. In total, Lower Miocene of the Lagerst?tte Bílina Mine exhibits a high level of external foliage feeding types (23.7%), and a low level of more specialized DT, such as galls (4.3%) and leaf mines (<1%). A broader comparison based on DT of the main sedimentary environments shows significance supporting different biomes by frequency of damage levels and DT diversities.  相似文献   

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Research on vegetation change, rangeland assessment or desertification modelling in drylands using remotely sensed image acquisition normally ignores long-term rainfall as a key criterion in image acquisition. This article will present a novel procedure for image acquisition to investigate vegetation change in a degraded rangeland located in Western New South Wales (Western NSW) Australia. Western NSW experienced an unusually prolonged period of rainfall deficit during the 2000s compared to the 1970, 1980 and 1990s. For this purpose, vegetation changes were assessed using Landsat images supported by field survey. The long-term rainfall variability (42-year) was regarded as a key element in image acquisition. Within the timeframe of the 2000s, 2 years with 25 % lower than the 42-year mean annual rainfall were selected. These images were then compared to an image captured in a year (1988) with rainfall closer to the 42-year mean annual rainfall. Two change detection techniques were used, namely univariate image differencing and GIS approaches. Classification of the produced images was pursued based on the digital numbers (supervised) of ground-checked points within the reference image whilst considering the histogram (unsupervised) of each digital number of the produced image. This research emphasized rainfall as a key variable in image acquisition for vegetation change analysis in rangelands. Image acquisition based on long-term rainfall data allowed for the assessment of changes in perennial plant cover by eliminating the effects of extreme rainfall variation on annual grass dynamics and removing extreme reflections caused by their temporary high photosynthetic activity.  相似文献   

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