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Structure Parameters and Physiological Indices Research of High-quality and High-yield Apple Orchards 被引量:1
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作者 薛晓敏 王翠玲 +2 位作者 王金政 孟海凤 聂佩显 《Agricultural Science & Technology》 CAS 2014年第11期1953-1956,1959,共5页
In order to research environment parameters and physiological indices of high-quality and high-yield apple trees, two orchards with young and mature apples trees were investigated to explore structural parameter of ap... In order to research environment parameters and physiological indices of high-quality and high-yield apple trees, two orchards with young and mature apples trees were investigated to explore structural parameter of apple tree and community, and some physiological indices in fields and by room measurements. The results showed that tree height of high-quality orchard was in the range of 260 to 290 cm, branch angle in 70°-75°, and orchard coverage rate in 75%-94%, and the connec-tion rates between rows and trees were lower. Furthermore, the total branches of mature orchard reached 1.04 ×106 per hm2, while the young orchard was 8.79 ×105 per hm2; the leaves were thick and chlorophyl content was high, with SPAD value at 58.22. Additional y, the photosynthesis of the orchard was strong, and net photo-synthetic rate was 17.48-21.8 μmolCO2/(m2·s). The proportions of lateral shoot of bearing part were 81% and 75% respectively. 展开更多
关键词 High-quality and high-yield Apple orchard structure parameters Physio-logical index
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Woody plant diversity,structure and regeneration in the Ambo State Forest,South Gondar Zone,Northwest Ethiopia 被引量:2
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作者 Solomon Melaku Melese Belayneh Ayele 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期133-144,共12页
For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a t... For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a transect line. For assessing seedlings and saplings, two 2 × 10 m sub quadrats were set upon opposite sides of each main quadrat. Data on species diversity, abundance, structure, basal area, density, frequency and regeneration status were collected and analyzed using standard procedures and programs. Of 58 woody plant species identified, 69 % were trees, 16 % were shrubs, 12 % were tree/shrubs and 4 % were climbers. Fabaceae was the most speciesrich family comprising 17 species. The Shannon-Weiner diversity index was 2.73, and evenness was 0.67. The population structure in the cumulative diameter class frequency distribution revealed an interrupted and inverted J-shape with a very high decrease in higher diameter class. Acacia lahai (49 %) was the most important woody species with the highest importance value index. To maintain balanced structure, enhanced regeneration and protecting the forest from selective cutting are recommended. 展开更多
关键词 Ambo Forest DIVERSITY structure -Importance value index Regeneration status
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Comparing of Aviation Network Structure of Mid-south,Northwest and Southwest of China Based on Hierarchical Index Model 被引量:1
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作者 Cheng Xiangjun Yang Fang Xie Li 《Journal of Traffic and Transportation Engineering》 2020年第1期14-19,共6页
In order to compare the aviation network of mid-south,northwest and southwest of China to reveal the structure similarity and difference for providing quantitative evidence to construct regional aviation network and i... In order to compare the aviation network of mid-south,northwest and southwest of China to reveal the structure similarity and difference for providing quantitative evidence to construct regional aviation network and improve its structure,hierarchical index model of regional aviation network was established through dividing the aviation network into layers to research its structure characters.Data matrixes were defined to record the basic state of regional aviation network.Index matrixes were constructed to describe the quantitative features of regional aviation network.On the basis of these indexes,several structure indexes of all layers of aviation network were calculated to show the structure features of aviation network,such as ratio of passenger volume within the region with across the region,share rate of passenger volume among layers,ratio of average number of airline for each airport,ratio of average passenger volume for each airline and ratio of airline rate.According to the statistical data,similar structure of share rate of passenger volume among layers and average passenger volume for each airline in their regional aviation network was found after calculating.But on the side of ratio of passenger volume within the region with across the region,ratio of average number of airlines for each airport and ratio of airline rate were different. 展开更多
关键词 Regional aviation network comparing of structure hierarchical index model index matrix structure index
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HiSC:A Hybrid XML Index Composing Structure-Encoded with Cluster
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作者 YANG Jincai ZHANG Lin 《Wuhan University Journal of Natural Sciences》 CAS 2007年第5期840-844,共5页
A new way of indexing and processing twig patterns in an XML documents is proposed in this paper. Every path in XML document can be transformed into a sequence of labels by Structure-Encoded that constructs a one-to-o... A new way of indexing and processing twig patterns in an XML documents is proposed in this paper. Every path in XML document can be transformed into a sequence of labels by Structure-Encoded that constructs a one-to-one correspondence between XML tree and sequence. Base on identifying characteristics of nodes in XML tree, the elements are classified and clustered. During query proceeding, the twig pattern is also transformed into its Structure-Encoded. By performing subsequence matching on the set of sequences in XML documents, all the occurrences of path in the XML documents are refined. Using the index, the numbers of elements retrieved are minimized. The search results with pertinent format provide more structure information without any false dismissals or false alarms. The index also supports keyword search Experiment results indicate the index has significantly efficiency with high precision. 展开更多
关键词 XML index structure cluster index region coding structure-encoded keyword search
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Structured scene modeling using micro stereo vision system with large field of view
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作者 颜世莹 朱玉文 +1 位作者 刘佳音 贾云得 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第3期296-299,共4页
This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with principle axi... This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with principle axis based approach, finding corresponding lines using feature based matching method, and 3D line depth computation. 展开更多
关键词 Index terms structured scene modeling stereo vision wide field of view mobile robot
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Structure Evolution of China Aviation Network Based on Hierarchical Model
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作者 Cheng Xiangjun Chen Xumei Li Tao 《Journal of Traffic and Transportation Engineering》 2022年第3期95-103,共9页
The annual passenger volume of airport reflected its passenger transport scale and the role in aviation network.The airports in whole country were divided into three layers:first layer airports,second layer airports a... The annual passenger volume of airport reflected its passenger transport scale and the role in aviation network.The airports in whole country were divided into three layers:first layer airports,second layer airports and third layer airports.The airlines from the first layer airports consisted the first layer aviation network.The airlines from the second layer airports consisted the second layer aviation network.The airlines from the third layer airports consisted the third layer aviation network.The structure and function of different layer aviation network had significant differences.These differences were shown in the number of airlines,average number of airlines of each airport,annual passenger volume of airport and average passenger volume of each airline.National aviation network hierarchical model was constructed to describe the whole country aviation network.The matrix was built to describe the airline number,annual passenger volume,average number of airlines,average passenger volume of each airport and airline rate of aviation network.The index of national aviation network structure was constructed to show the ratio of index between different aviation network layer to describe the aviation network structure.The structure index was built to illustrate the macrostructural features of national aviation network.The statistics data in year 1988,1994,2001,2008 and 2015 of China aviation network were analyzed and basic data matrixes,basic index matrixes and structure index matrixes were calculated.The trend of ratio of corresponding index between the first layer and the second layer showed the change of basic structure of China aviation network.At meantime,the tendency of ratio of corresponding index between the third layer and the second layer also showed the change of basic structure.The trend of network general structure index illustrated that the large scaled new airports and airlines construction had significant influence on the national aviation network structure. 展开更多
关键词 National aviation network structure evolution hierarchical model structure index matrix
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Profile and Character of Atmospheric Structure Constant of Refractive Index C_n^2
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作者 SUN Gang WENG Ning-Quan +1 位作者 XIAO Li-Ming WU Yi 《Atmospheric and Oceanic Science Letters》 2012年第3期270-272,共3页
Random fluctuations of turbulence bring random fluctuations of the refractive index, making the atmosphere a random fluctuation medium that destroys the coherence of light-waves. Research in atmospheric turbulence is ... Random fluctuations of turbulence bring random fluctuations of the refractive index, making the atmosphere a random fluctuation medium that destroys the coherence of light-waves. Research in atmospheric turbulence is actually the investigation of the atmospheric refractive index. The atmospheric structure constant of refractive index, C n 2 , is an important parameter denoting atmospheric turbulence. In this paper, C n 2 is measured during the day and at night and in all four seasons using a high sensitivity micro-thermal meter QHTP-2. The vertical profile of C n 2 in Hefei (0-30 km) is investigated by the analysis of experimental data. The average profile of C n 2 in Hefei exhibits conspicuous day and night differences with increased altitude. The distribution of log(C n 2 ) is nearly normal and has conspicuous seasonal differences. 展开更多
关键词 applied optics atmospheric turbulence atmospheric structure constant of refractive index variance profile
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Joint inversion of gravity and vertical gradient data based on modified structural similarity index for the structural and petrophysical consistency constraint
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作者 Sheng Liu Xiangyun Wan +6 位作者 Shuanggen Jin Bin Jia Quan Lou Songbai Xuan Binbin Qin Yiju Tang Dali Sun 《Geodesy and Geodynamics》 EI CSCD 2023年第5期485-499,共15页
Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysica... Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results. 展开更多
关键词 Joint inversion Gravity and vertical gradient data Modified structural similarity index
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Underwater Image Enhancement Using MIRNet
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作者 M.Thamarai S P Aruna +1 位作者 Kamesh Sonti P.Sudheer Chakravarthi 《Journal of Electronic & Information Systems》 2023年第1期36-44,共9页
In recent years,enhancement of underwater images is a challenging task,which is gaining priority since the human eye cannot perceive images under water.The significant details underwater are not clearly captured using... In recent years,enhancement of underwater images is a challenging task,which is gaining priority since the human eye cannot perceive images under water.The significant details underwater are not clearly captured using the conventional image acquisition techniques,and also they are expensive.Hence,the quality of the image processing algorithms can be enhanced in the absence of costly and reliable acquisition techniques.Traditional algorithms have certain limitations in the case of these images with varying degrees of fuzziness and color deviation.In the proposed model,the authors used a deep learning model for underwater image enhancement.First,the original image is pre-processed by the white balance algorithm for colour correction and the contrast of the image is improved using the contrast enhancement technique.Next,the pre-processed image is given to the MIRNet for enhancement.MIRNet is a deep learning framework that can be used to enhance the low-light level images.The enhanced image quality is measured using peak signal-to-noise ratio(PSNR),root mean square error(RMSE),and structural similarity index(SSIM)parameters. 展开更多
关键词 UNDERWATER Deep learning MIRNet Peak signal-to-noise ratio Structural similarity index
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Improved Euler method for the interpretation of potential data based on the ratio of the vertical fi rst derivative to analytic signal 被引量:2
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作者 郭灿灿 熊盛青 +1 位作者 薛典军 王林飞 《Applied Geophysics》 SCIE CSCD 2014年第3期331-339,352,共10页
We propose a new automatic method for the interpretation of potential fi eld data, called the RDAS–Euler method, which is based on Euler's deconvolution and analytic signal methods. The proposed method can estimate ... We propose a new automatic method for the interpretation of potential fi eld data, called the RDAS–Euler method, which is based on Euler's deconvolution and analytic signal methods. The proposed method can estimate the horizontal and vertical extent of geophysical anomalies without prior information of the nature of the anomalies(structural index). It also avoids inversion errors because of the erroneous choice of the structural index N in the conventional Euler deconvolution method. The method was tested using model gravity anomalies. In all cases, the misfi t between theoretical values and inversion results is less than 10%. Relative to the conventional Euler deconvolution method, the RDAS–Euler method produces inversion results that are more stable and accurate. Finally, we demonstrate the practicability of the method by applying it to Hulin Basin in Heilongjiang province, where the proposed method produced more accurate data regarding the distribution of faults. 展开更多
关键词 Euler deconvolution analytic signal edge identifi cation structural index
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Vehicle Dynamic State Estimation: State of the Art Schemes and Perspectives 被引量:12
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作者 Hongyan Guo Dongpu Cao +3 位作者 Hong Chen Chen Lv Huaji Wang Siqi Yang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第2期418-431,共14页
Next-generation vehicle control and future autonomous driving require further advances in vehicle dynamic state estimation. This article provides a concise review, along with the perspectives, of the recent developmen... Next-generation vehicle control and future autonomous driving require further advances in vehicle dynamic state estimation. This article provides a concise review, along with the perspectives, of the recent developments in the estimation of vehicle dynamic states. The definitions used in vehicle dynamic state estimation are first introduced, and alternative estimation structures are presented. Then, the sensor configuration schemes used to estimate vehicle velocity, sideslip angle, yaw rate and roll angle are presented. The vehicle models used for vehicle dynamic state estimation are further summarized, and representative estimation approaches are discussed. Future concerns and perspectives for vehicle dynamic state estimation are also discussed. 展开更多
关键词 Index Terms-Estimation structure extended Kalman filter sensor configuration sideslip angle estimation vehicle dynamicstate estimation vehicle dynamics model.
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Cache-Conscious Index Mechanism for Main-Memory Databases 被引量:5
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作者 SUN Li-mei SONG Bao-yan YU Ya-xin LI Fang-fang YU Ge 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第1期309-312,共4页
Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^+-tree are shown to outperform conventional main memory indic... Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^+-tree are shown to outperform conventional main memory indices such as the AVL-tree and the T-tree. This paper proposes a cacheconscious version of the T-tree, CST-tree, defined according to the cache-conscious definition. To separate the keys within a node into two parts, the CST-tree can gain higher cache hit ratio. 展开更多
关键词 index structure main memory database real time application cache-conscious T-tree indexing CST-tree indexing
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Quantifying forest structural diversity based on large-scale inventory data:a new approach to support biodiversity monitoring 被引量:3
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作者 Felix Storch Carsten F.Dormann Jurgen Bauhus 《Forest Ecosystems》 SCIE CSCD 2018年第4期472-485,共14页
Background: The importance of structurally diverse forests for the conservation of biodiversity and provision of a wide range of ecosystem services has been widely recognised. However, tools to quantify structural div... Background: The importance of structurally diverse forests for the conservation of biodiversity and provision of a wide range of ecosystem services has been widely recognised. However, tools to quantify structural diversity of forests in an objective and quantitative way across many forest types and sites are still needed, for example to support biodiversity monitoring. The existing approaches to quantify forest structural diversity are based on small geographical regions or single forest types, typically using only small data sets.Results: Here we developed an index of structural diversity based on National Forest Inventory(NFI) data of BadenWurttemberg, Germany, a state with 1.3 million ha of diverse forest types in different ownerships. Based on a literature review, 11 aspects of structural diversity were identified a priori as crucially important to describe structural diversity. An initial comprehensive list of 52 variables derived from National Forest Inventory(NFI) data related to structural diversity was reduced by applying five selection criteria to arrive at one variable for each aspect of structural diversity. These variables comprise 1) quadratic mean diameter at breast height(DBH), 2) standard deviation of DBH, 3) standard deviation of stand height, 4) number of decay classes, 5) bark-diversity index, 6) trees with DBH ≥ 40 cm, 7) diversity of flowering and fructification, 8) average mean diameter of downed deadwood, 9) mean DBH of standing deadwood, 10) tree species richness and 11) tree species richness in the regeneration layer. These variables were combined into a simple,additive index to quantify the level of structural diversity, which assumes values between 0 and 1. We applied this index in an exemplary way to broad forest categories and ownerships to assess its feasibility to analyse structural diversity in large-scale forest inventories.Conclusions: The forest structure index presented here can be derived in a similar way from standard inventory variables for most other large-scale forest inventories to provide important information about biodiversity relevant forest conditions and thus provide an evidence-base for forest management and planning as well as reporting. 展开更多
关键词 Stand structure Structural diversity Structural diversity index Large-scale forest inventory Angle count sampling
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Fast local wavenumber (FLW) method for the inversion of magnetic source parameters 被引量:1
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作者 Ma Guo-Qing Ming Yan-Bo +2 位作者 Han Jiang-Tao Li Li-Li Meng Qing-Fa 《Applied Geophysics》 SCIE CSCD 2018年第2期353-360,365,共9页
The current local wavenumber methods for the interpretation of magnetic anomalies compute the locations of geological bodies by solving complex matrices. Presently, such methods require to know the structural index, w... The current local wavenumber methods for the interpretation of magnetic anomalies compute the locations of geological bodies by solving complex matrices. Presently, such methods require to know the structural index, which is a parameter that represents the source type. The structural index is hard to know in real data; consequently, the precision of current methods is low. We present the fast local wavenumber (FLW) method, and define the squared sum of the horizontal and vertical local wavenumbers as the cumulative local wavenumber. The FLW method is the linear combination of the umulative local wavenumberand other wavenumbers, and is used to compute the locations and structural index of the source without a priori information and matrix solution. We apply the FLW method to synthetic magnetic anomalies, and the results suggest that the FLW method is insensitive to background and oblique magnetization. Next, we apply the FLW method to real magnetic data to obtain the location and structural index of the source. 展开更多
关键词 Local wavenumber magnetic anomaly structural index
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Inversion of Biochemical Parameters by Selection of Proper Vegetation Index in Winter Wheat 被引量:2
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作者 HUANGWen-jiang WANGJi-hua +3 位作者 LIULiang-yun ZHAOChun-jiang WANGZhi-jie WANGJin-di 《Agricultural Sciences in China》 CAS CSCD 2004年第3期178-185,共8页
Recent studies have demonstrated the application of vegetation indices from canopy reflectedspectrum for inversion of chlorophyll concentration. Some indices are both response tovariations of vegetation and environmen... Recent studies have demonstrated the application of vegetation indices from canopy reflectedspectrum for inversion of chlorophyll concentration. Some indices are both response tovariations of vegetation and environmental factors. Canopy chlorophyll concentration, anindicator of photosynthesis activity, is related to nitrogen concentration in green vegetationand serves as an indicator of the crop response to soil nitrogen fertilizer application. Thecombination of normalized difference vegetation index (NDVI) and photochemical reflectanceindex (PRI) can reduce the effect of leaf area index (LAI) and soil background. The canopychlorophyll inversion index (CCII) was proved to be sensitive to chlorophyll concentration andvery resistant to the other variations. This paper introduced the ratio of TCARI/OSAVI to makeaccurate predictions of winter wheat chlorophyll concentration under different cultivars. Itindicated that canopy chlorophyll concentration could be evaluated by some combined vegetationindices. 展开更多
关键词 Winter wheat Canopy reflected spectrum structure Insensitive Vegetation Index Chlorophyll concentration
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Denoising Letter Images from Scanned Invoices Using Stacked Autoencoders 被引量:1
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作者 Samah Ibrahim Alshathri Desiree Juby Vincent V.S.Hari 《Computers, Materials & Continua》 SCIE EI 2022年第4期1371-1386,共16页
Invoice document digitization is crucial for efficient management in industries.The scanned invoice image is often noisy due to various reasons.This affects the OCR(optical character recognition)detection accuracy.In ... Invoice document digitization is crucial for efficient management in industries.The scanned invoice image is often noisy due to various reasons.This affects the OCR(optical character recognition)detection accuracy.In this paper,letter data obtained from images of invoices are denoised using a modified autoencoder based deep learning method.A stacked denoising autoencoder(SDAE)is implemented with two hidden layers each in encoder network and decoder network.In order to capture the most salient features of training samples,a undercomplete autoencoder is designed with non-linear encoder and decoder function.This autoencoder is regularized for denoising application using a combined loss function which considers both mean square error and binary cross entropy.A dataset consisting of 59,119 letter images,which contains both English alphabets(upper and lower case)and numbers(0 to 9)is prepared from many scanned invoices images and windows true type(.ttf)files,are used for training the neural network.Performance is analyzed in terms of Signal to Noise Ratio(SNR),Peak Signal to Noise Ratio(PSNR),Structural Similarity Index(SSIM)and Universal Image Quality Index(UQI)and compared with other filtering techniques like Nonlocal Means filter,Anisotropic diffusion filter,Gaussian filters and Mean filters.Denoising performance of proposed SDAE is compared with existing SDAE with single loss function in terms of SNR and PSNR values.Results show the superior performance of proposed SDAE method. 展开更多
关键词 Stacked denoising autoencoder(SDAE) optical character recognition(OCR) signal to noise ratio(SNR) universal image quality index(UQ1)and structural similarity index(SSIM)
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Enhanced Structural Complexity Index:An Improved Index for Describing Forest Structural Complexity 被引量:1
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作者 Philip Beckschafer Philip Mundhenk +3 位作者 Christoph Kleinn Yinqiu Ji Douglas W.Yu Rhett D.Harrison 《Open Journal of Forestry》 2013年第1期23-29,共7页
The horizontal distribution of stems, stand density and the differentiation of tree dimensions are among the most important aspects of stand structure. An increasing complexity of stand structure is often linked to a ... The horizontal distribution of stems, stand density and the differentiation of tree dimensions are among the most important aspects of stand structure. An increasing complexity of stand structure is often linked to a higher number of species and to greater ecological stability. For quantification, the Structural Complexity Index (SCI) describes structural complexity by means of an area ratio of the surface that is generated by connecting the tree tops of neighbouring trees to form triangles to the surface that is covered by all triangles if projected on a flat plane. Here, we propose two ecologically relevant modifications of the SCI: The degree of mingling of tree attributes, quantified by a vector ruggedness measure, and a stem density term. We investigate how these two modifications influence index values. Data come from forest inventory field plots sampled along a disturbance gradient from heavily disturbed shrub land, through secondary regrowth to mature montane rainforest stands in Mengsong, Xishuangbanna,Yunnan,China. An application is described linking structural complexity, as described by the SCI and its modified versions, to changes in species composition of insect communities. The results of this study show that the Enhanced Structural Complexity Index (ESCI) can serve as a valuable tool for forest managers and ecologists for describing the structural complexity of forest stands and is particularly valuable for natural forests with a high degree of structural complexity. 展开更多
关键词 Forest structure Index Structural Complexity Stem Map Species Composition NMDS
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Fully automatic identification and discrimination of sperm’s parts in microscopic images of stained human semen smear 被引量:1
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作者 Ahmad Bijar Antonio Penalver Benavent +1 位作者 Mohammad Mikaeili Rasoul Khayati 《Journal of Biomedical Science and Engineering》 2012年第7期384-395,共12页
In the last years, digital image processing and analysis are used for computer assisted evaluation of semen quality with therapeutic goals or to estimate its fertility by means of spermatozoid motility and morphology.... In the last years, digital image processing and analysis are used for computer assisted evaluation of semen quality with therapeutic goals or to estimate its fertility by means of spermatozoid motility and morphology. Sperm morphology is assessed routinely as part of standard laboratory analysis in the diagnosis of human male infertility. Nowadays assessments of sperm morphology are mostly done based on subjective criteria. In order to avoid subjectivity, numerous studies that incorporate image analysis techniques in the assessment of sperm morphology have been proposed. The primary step of all these methods is segmentation of sperm’s parts. In this paper, we have proposed a new method for segmentation of sperm’s Acrosome, Nucleus, Mid-piece and identification of sperm’s tail through some points which are placed on the sperm’s tail, accurately. These estimated points could be used to verify the morphological characteristics of sperm’s tail such as length, shape and etc. At first, sperm’s Acrosome, Nucleus and Mid-piece are segmented through a method based on a Bayesian classifier which utilizes the entropy based expectation–maximization (EM) algorithm and Markov random field (MRF) model to obtain and upgrade the class conditional probability density function (CCPDF) and the apriori probability of each class. Then, a pixel at the end of sperm’s Mid-piece, is selected as an initial point. To find other pixels which are placed on the sperm’s tail, structural similarity index (SSIM) is used in an iterative scheme. In order to stop the algorithm automatically at the end of sperm’s tail, local entropy is estimated and used as a feature to determine if a point is located on the sperm’s tail or not. To compare the performance of the proposed approach with those of previous approaches including manual segmentation, the Accuracy, Sensitivity and Specificity were calculated. 展开更多
关键词 SPERM Segmentation Rotating Calipers Bayesian Classification Entropy Based EM Algorithm Structural Similarity Index(SSIM) ENTROPY
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Automatic DEXP method derived from Euler’s Homogeneity equation
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作者 Zhao Guo-xing Wu Yong-ting +3 位作者 Sun Yang Zhang Bin-bin Zhou Xin Wang Feng-jun 《Applied Geophysics》 SCIE CSCD 2022年第4期572-579,605,共9页
The depth from extreme points(DEXP)method can be used for estimating source depths and providing a rough image as a starting model for inversion.However,the application of the DEXP method is limited by the lack of pri... The depth from extreme points(DEXP)method can be used for estimating source depths and providing a rough image as a starting model for inversion.However,the application of the DEXP method is limited by the lack of prior information regarding the structural index.Herein,we describe an automatic DEXP method derived from Euler’s Homogeneity equation,and we call it the Euler–DEXP method.We prove that its scaling field is independent of structural indices,and the scaling exponent is a constant for any potential field or its derivative.Therefore,we can simultaneously estimate source depths with diff erent geometries in one DEXP image.The implementation of the Euler–DEXP method is fully automatic.The structural index can be subsequently determined by utilizing the estimated depth.This method has been tested using synthetic cases with single and multiple sources.All estimated solutions are in accordance with theoretical source parameters.We demonstrate the practicability of the Euler–DEXP method with the gravity field data of the Hastings Salt Dome.The results ultimately represent a better understanding of the geometry and depth of the salt dome. 展开更多
关键词 depth from extreme points Euler’s Homogeneity equation DEPTH structural index AUTOMATION
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Field source characteristic of gravity variation in Hexi region before Menyuan Ms6.4 earthquake based on the Euler deconvolution
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作者 Fang Liu Yingwei Wang Weifeng Liang 《Geodesy and Geodynamics》 2016年第5期317-322,共6页
This study adopted the Euler deconvolution method to conduct an inversion and interpretation of the depth and spatial distribution pattern of field source that lead to gravity variation. For this purpose, mobile gravi... This study adopted the Euler deconvolution method to conduct an inversion and interpretation of the depth and spatial distribution pattern of field source that lead to gravity variation. For this purpose, mobile gravity data from four periods in the Hexi region between 2011 and 2015 were obtained from an observation network. With a newly established theoretical model, we acquired the optimum inversion parameters and conducted calculation and analysis with the actual data. The results indicate that one is the appropriate value of the structure index for the inversion of the mobile gravity data. The inversion results of the actual data showed a comparable spatial distribution of the field source and a consistent structural trend with observations from the Qilian-Haiyuan Fault zone between 2011 and 2015. The distribution was in a blocking state at the epicenter of the Menyuan earthquake in 2016. Our quantitative study of the field source provides new insights into the inversion and interpretation of signals of mobile gravity variation. 展开更多
关键词 Euler deconvolution Potential field inversion Gravity variation Structural index Menyuan Ms6.4 earthquake
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