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Structured Multi-Head Attention Stock Index Prediction Method Based Adaptive Public Opinion Sentiment Vector
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作者 Cheng Zhao Zhe Peng +2 位作者 Xuefeng Lan Yuefeng Cen Zuxin Wang 《Computers, Materials & Continua》 SCIE EI 2024年第1期1503-1523,共21页
The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment ... The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment risk.The quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of research.In this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is proposed.The proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex sentiments.It then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention mechanism.The experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity analysis.Furthermore,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information separately.Themean absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention algorithm.Additionally,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark algorithm.These results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits. 展开更多
关键词 Public opinion sentiment structured multi-head attention stock index prediction deep learning
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A three-layer model for the thermal structure in the Huanghai Sea
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《Acta Oceanologica Sinica》 SCIE CAS CSCD 1990年第2期159-172,共14页
A one-dimentional three-layer model for the thermal structure in the Huanghai Sea is presented in this study, me model consists of the upper mixed layer caused by heating and wind mixing, the lower mixed layer driven ... A one-dimentional three-layer model for the thermal structure in the Huanghai Sea is presented in this study, me model consists of the upper mixed layer caused by heating and wind mixing, the lower mixed layer driven by tidal mixing, and the thermocline with certain thickness. The entrainment velocities of the upper and lower layers are obtained respectively. The results show that the model is capable of describing the development and decline processes of the seasonal thermocline in the Huanghai Sea, simulating successfully the Huanghai Sea Cold Water Mass, the nearshore front and surface cold water off North Jiangsu and explaining reasonably their formation mechanisms as well as the strong thermocline off Qingdao. It is suggested that the tidal mixing plays key role in the formation of the nearshore front off North Jiangsu and the strong thermocline off Qingdao. The wind mixing and the tidal mixing make the lower layer water with high nutrients go up to the upper layer. This physical process may be significant for biological plant production. 展开更多
关键词 A three-layer model for the thermal structure in the Huanghai Sea
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Deformation warning index for reinforced concrete dam based on structural health monitoring data and numerical simulation 被引量:1
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作者 Ming-qiang Zhan Bo Chen Zhong-ru Wu 《Water Science and Engineering》 EI CAS CSCD 2023年第4期408-418,共11页
The material mechanical parameters of the dam body and foundation will change when a dam is reinforced during the aging process.This causes significant changes in the structural state of the project and makes it diffi... The material mechanical parameters of the dam body and foundation will change when a dam is reinforced during the aging process.This causes significant changes in the structural state of the project and makes it difficult to ensure its structural safety.In this study,a new deformation warning index for reinforced concrete dams was developed according to the prototype monitoring data,statistical models,three-dimensional finite element model(FEM)numerical simulation,and the critical conditions of the dam structure.A statistical model was established to separate the water pressure component.Then,a three-dimensional FEM of the reinforced concrete dam was constructed to simulate the water pressure component.Furthermore,the deformation components that affected the mechanical parameters of the dam under the same amount of reservoir water level change were separated and quantified accurately.In addition,the method for inversion of comprehensive mechanical parameters after dam reinforcement was used.The influence mechanisms of the deformation behavior of concrete dams under the reservoir water level and temperature changes were investigated.A new deformation warning index was developed by combining the forward-simulated critical water pressure component and temperature component in the period of extreme temperature decrease with the aging component separated by the statistical model.The new deformation warning index considers the structural state of the dam before and after reinforcement and links the structural strength criterion and the deformation evolution mechanisms.It provides a theoretical foundation and decision support for long-term service and operation management of reinforced dams. 展开更多
关键词 Deformation warning index structural health monitoring Finite element simulation REINFORCEMENT Multiple-arch dam Parameter inverse analysis
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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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A Full-Scale Optimization of a Crop Spatial Planting Structure and its Associated Effects
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作者 Qi Liu Jun Niu +1 位作者 Taisheng Du Shaozhong Kang 《Engineering》 SCIE EI CAS CSCD 2023年第9期139-152,共14页
Driven by the concept of agricultural sustainable development,crop planting structure optimization(CPSO)has become an effective measure to reduce regional crop water demand,ensure food security,and protect the environ... Driven by the concept of agricultural sustainable development,crop planting structure optimization(CPSO)has become an effective measure to reduce regional crop water demand,ensure food security,and protect the environment.However,traditional optimization of crop planting structures often ignores the impact on regional food supply–demand relations and interprovincial food trading.Therefore,using a system analysis concept and taking virtual water output as the connecting point,this study proposes a theoretical CPSO framework based on a multi-aspect and full-scale evaluation index system.To this end,a water footprint(WF)simulation module denoted as soil and water assessment tool–water footprint(SWAT-WF)is constructed to simulate the amount and components of regional crop WFs.A multi-objective spatial CPSO model with the objectives of maximizing the regional economic water productivity(EWP),minimizing the blue water dependency(BWFrate),and minimizing the grey water footprint(GWFgrey)is established to achieve an optimal planting layout.Considering various benefits,a fullscale evaluation index system based on region,province,and country scales is constructed.Through an entropy weight technique for order preference by similarity to an ideal solution(TOPSIS)comprehensive evaluation model,the optimal plan is selected from a variety of CPSO plans.The proposed framework is then verified through a case study of the upper–middle reaches of the Heihe River Basin in Gansu province,China.By combining the theory of virtual water trading with system analysis,the optimal planting structure is found.While sacrificing reasonable regional economic benefits,the optimization of the planting structure significantly improves the regional water resource benefits and ecological benefits at different scales. 展开更多
关键词 Planting structure optimization Full-scale evaluation index system Water footprint SWAT-WF module Interprovincial food trade Entropy weight TOPSIS
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Structure and Nonlinear Refractive Index of Bismuth Borate Glass 被引量:1
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作者 范慧艳 胡丽丽 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第B12期868-872,共5页
The method of conventional glass melting is used to study the glass formation region of Bi2O3-B2O3-TiO2-La2O3 system. The instrument of Differential Scanning Calorimeter (DSC) is used to research the glass stability... The method of conventional glass melting is used to study the glass formation region of Bi2O3-B2O3-TiO2-La2O3 system. The instrument of Differential Scanning Calorimeter (DSC) is used to research the glass stability. Raman spectra and IR spectra are used to speculate on the structure of glasses. The refractive index of glass is measured by prism coupler. With increase of Bi2O3, the glass stability, the amount of [BiO3] group and boron-oxygen loops decrease, while the content of B-O- bond, refractive index and nonlinear refractive index increase. 展开更多
关键词 bismuth glass glass structure nonlinear refractive index
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Effects of Phenyl Content and Molecular Structure on the Refractive Index of Organic Silicon Polymer 被引量:1
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作者 朱淮军 戴子林 涂伟萍 《Journal of Donghua University(English Edition)》 EI CAS 2017年第4期503-506,共4页
The effects of phenyl content and group distribution on the refractive index of phenyl silicone oil were investigated by synthesis and characterization of silicone oils of different molecular structures.A group contri... The effects of phenyl content and group distribution on the refractive index of phenyl silicone oil were investigated by synthesis and characterization of silicone oils of different molecular structures.A group contribution function model was established to predict the refractive index. The results showed that refractive index of phenyl silicone oil increased as its phenyl content increased. A linear equation had been established to describe the quantitative relationship between the refractive index and phenyl content.Refractive index values from the group contribution function model showed good consistency with experimental results. 展开更多
关键词 phenyl silicone oil refractive index phenyl content group contribution method molecular structure
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How Users Perceive Infrastructure Development Affects Their Transport Mode Choice
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作者 Lina Shbeeb 《Journal of Transportation Technologies》 2023年第4期545-598,共54页
Transport infrastructure development and perception vary across and within countries, influencing mode choice among road users. This study explores how road users perceive the development of infrastructure modes, serv... Transport infrastructure development and perception vary across and within countries, influencing mode choice among road users. This study explores how road users perceive the development of infrastructure modes, service attributes, embedded safety levels, and commuting modes. Additionally, the research examines whether participants’ environmental backgrounds impact their mode choice patterns. The study gathered responses from 1169 participants residing in two regions of Amman, Jordan, each with distinct infrastructure development and population densities. Participants completed a standardized questionnaire, and several statistical techniques were employed for analysis. The findings revealed that facilities’ infrastructure attributes, development, and safety were assessed using three indices. Both participant groups perceived these indices differently on average. Residents of low population density areas with relatively developed infrastructure showed more consistent assessments, irrespective of their most frequently used mode of transportation, tending towards lower scores. Interestingly, subjective ratings of infrastructure development were higher (4.96) than attribute-based ratings (4.32). Despite their generally low-quality perception, public transportation services received the highest appraisal (4.9). Conversely, pedestrian infrastructure complementing public transport received the lowest assessment (4.57), only slightly higher than street environments (4.59). The study found weak associations between subjective service characteristics ratings. Traveler and trip characteristics influenced mode choice and trips more than infrastructure perception. In conclusion, the study suggests that policies should be developed to encourage green transportation, ensure social equality and safety. In addition, the study contributes to understanding perceptions about transport infrastructure, modes of transportation, and the factors that influence sustainable and equitable transportation systems. 展开更多
关键词 Road index Infrastructure Development Infrastructure Attribute Safety Rating structural Equation Models Modal Choice
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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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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 大气结构 折射率结构常数 大气折射率 字符 随机波动 大气湍流 季节性差异 高灵敏度
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Evaluating spatial structure of a mixed broad-leaved/Korean pine forest based on neighborhood relationships in Mudanfeng National Nature Reserve,China 被引量:6
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作者 Miao Yang Tijiu Cai +1 位作者 Cunyong Ju Hongfei Zou 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第4期1375-1381,共7页
China’s 13 th 5-year forestry plan explicitly requires the end of commercial harvesting and the improved management of natural forests by means of adjusting and optimizing forest structure and developing high-quality... China’s 13 th 5-year forestry plan explicitly requires the end of commercial harvesting and the improved management of natural forests by means of adjusting and optimizing forest structure and developing high-quality forest production.This requires the quantification of stand structure and species diversity.In this study,species distribution,association and size differentiation in a mixed broad-leaved/Korean pine(Pinus koraiensis Siebold&Zucc.)forest in Mudanfeng National Nature Reserve were analyzed using three spatial structure indices:uniform angle index,complete mingling index,and size differentiation index.The results show that the species were randomly distributed,with a moderate size differentiation and high mixed structure.Three dominant species exhibited different patterns in terms of the three indices and their bivariate distribution.Overall,Korean pine showed an opposite trend to Manchurian maple(Acer mandshuricum Maxim.),whereas the distribution pattern of Manchurian linden(Tilia mandshurica Rupr.&Maxim.)was similar to that of the entire stand.Our work contributes to further the knowledge of population structure in order to optimize the structure of secondary forests and plantations. 展开更多
关键词 structure parameter SPECIES association COMPLETE MINGLING index BIVARIATE distribution
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Different effects of economic and structural performance indexes on model construction of structural topology optimization 被引量:5
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作者 G.L.Yi Y.K.Sui 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第5期777-788,共12页
The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of str... The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of structural topology optimization are also discussed.Furthermore,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint(MCVC)model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint(MWDC)model,are presented.Based on a comparison of numerical example results,the conclusions can be summarized as follows:(1)under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;(2)the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;(3)constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering. 展开更多
关键词 Economic index Performance index structural topology optimization models MCVC model MWDC model Safety and economy
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Analysis of effect of nicotine on microbial community structure in sediment using PCR-DGGE fingerprinting 被引量:3
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作者 Ai-dong Ruan Chen-xiao Liu 《Water Science and Engineering》 EI CAS CSCD 2015年第4期309-314,共6页
Solid or liquid waste containing a high concentration of nicotine can pollute sediment in rivers and lakes, and may destroy the ecological balance if it is directly discharged into the environment without any treatmen... Solid or liquid waste containing a high concentration of nicotine can pollute sediment in rivers and lakes, and may destroy the ecological balance if it is directly discharged into the environment without any treatment. In this study, the polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) method was used to analyze the variation of the microbial community structure in the control and nicotinecontaminated sediment samples with nicotine concentration and time of exposure. The results demonstrated that the growth of some bacterial species in the nicotine-contaminated sediment samples was inhibited during the exposure. Some bacteria decreased in species diversity and in quantity with the increase of nicotine concentration or time of exposure, while other bacteria were enriched under the effect of nicotine, and their DGGE bands changed from undertones to deep colors. The microbial community structure, however, showed a wide variation in the nicotine- contaminated sediment samples, especially in the sediment samples treated with high-concentration nicotine. The Jaccard index was only 35.1% between the initial sediment sample and the sediment sample with a nicotine concentration of 0.030 μg/g after 28 d of exposure. Diversity indices showed that the contaminated groups had a similar trend over time. The diversity indices of contaminated groups all decreased in the first 7 d after exposure, then increased until day 42. It has been found that nicotine decreased the diversity of the microbial community in the sediment. 展开更多
关键词 NICOTINE SEDIMENT PCR-DGGE Microbial community structure Diversity index
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Plant Type and Its Effects on Canopy Structure at Heading Stage in Various Ecological Areas for a Two-line Hybrid Rice Combination,Liangyoupeijiu 被引量:3
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作者 LU Chuan-gen Hu Ning +2 位作者 YAO Ke-min XIA Shi-jian QI Qing-ming 《Rice science》 SCIE 2010年第3期235-242,共8页
A two-line hybrid rice combination, Liangyoupeijiu, was used to estimate several factors of plant type, and environmental models for these factors at the heading stage were established using the data of eight ecologic... A two-line hybrid rice combination, Liangyoupeijiu, was used to estimate several factors of plant type, and environmental models for these factors at the heading stage were established using the data of eight ecological experimental sites in 2006 and 2007. According to climatic data from 1951 to 2005, the differences in those factors and their effects on plant canopy were analyzed for four rice cropping areas in China, including South China, the middle-lower reaches of the Yangtze River, Sichuan Basin, and river valley in Yunnan, China. The thickness of leaf layer (the distance from pulvinus of the third leaf from the top to the tip of flag leaf) and distribution of leaf area could be used as candidate indices for the plant type of a rice canopy. 展开更多
关键词 hybrid rice plant type MODEL ecological area canopy structure 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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Coverless Information Hiding Based on the Molecular Structure Images of Material 被引量:10
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作者 Yi Cao Zhili Zhou +1 位作者 Xingming Sun Chongzhi Gao 《Computers, Materials & Continua》 SCIE EI 2018年第2期197-207,共11页
The traditional information hiding methods embed the secret information by modifying the carrier,which will inevitably leave traces of modification on the carrier.In this way,it is hard to resist the detection of steg... The traditional information hiding methods embed the secret information by modifying the carrier,which will inevitably leave traces of modification on the carrier.In this way,it is hard to resist the detection of steganalysis algorithm.To address this problem,the concept of coverless information hiding was proposed.Coverless information hiding can effectively resist steganalysis algorithm,since it uses unmodified natural stego-carriers to represent and convey confidential information.However,the state-of-the-arts method has a low hidden capacity,which makes it less appealing.Because the pixel values of different regions of the molecular structure images of material(MSIM)are usually different,this paper proposes a novel coverless information hiding method based on MSIM,which utilizes the average value of sub-image’s pixels to represent the secret information,according to the mapping between pixel value intervals and secret information.In addition,we employ a pseudo-random label sequence that is used to determine the position of sub-images to improve the security of the method.And the histogram of the Bag of words model(BOW)is used to determine the number of subimages in the image that convey secret information.Moreover,to improve the retrieval efficiency,we built a multi-level inverted index structure.Furthermore,the proposed method can also be used for other natural images.Compared with the state-of-the-arts,experimental results and analysis manifest that our method has better performance in anti-steganalysis,security and capacity. 展开更多
关键词 Coverless information hiding molecular structure images of material pixel value inverted index image retrieval bag of words model
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Semi-Probabilistic Evaluation of System Redundancy for Existing Offshore Structures 被引量:1
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《China Ocean Engineering》 SCIE EI 1995年第1期1-8,共8页
In this paper, a new definition of structure system redundancy is proposed in view of the various measures for structure redundancy. By introducing the terms of structure system failure at the mechanism level and equi... In this paper, a new definition of structure system redundancy is proposed in view of the various measures for structure redundancy. By introducing the terms of structure system failure at the mechanism level and equivalent reliability index, the safety for existing offshore platforms can be evaluated by the semi-probabilistic method presented in this paper. Some numerical examples are given and satisfactory results have been obtained. 展开更多
关键词 residual strength semi-probabilistic method damaged structure REDUNDANCY reliability index critical value
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Effect of exclosure ages on woody plant structure,diversity and regeneration potential in the western Tigray region of Ethiopia 被引量:1
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作者 Tsegay Gebregerges Zewdu K.Tessema Emiru Birhane 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第3期693-703,共11页
Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, incr... Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, we studied woody plant structure, diversity and regeneration potentials in 5-and 10-year grazing exclosures in comparison with open grazed sites in a semi-arid environment. Data on species diversity, abundance, structure, basal area, frequency, density, and regeneration status were collected from 270 sample plots. Forty-one woody species representing 20 families were identified, with 18, 28 and 38 species found in open grazed areas, and in 5-and 10-year grazing exclosures, respectively. The 10-year grazing exclosures had a higher(P <0.05) species richness and plant densities compared to the 5-year grazing exclosures and the open grazed areas. The population structure and regeneration status of woody species in both grazing exclosures showed an inverted J-shape, indicating a healthy regeneration status, whereas hampered regeneration was observed in open grazed areas. The establishment of grazing exclosures had positive effects in restoring woody plant diversity and improving vegetation structure and regeneration potentials of degraded grazing lands. 展开更多
关键词 Basal area DIVERSITY Important value index Population structure Regeneration status Species composition EXCLOSURES
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Determining relative block structure rating for rock erodibility evaluation in the case of non-orthogonal joint sets 被引量:1
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作者 Lamine Boumaiza Ali Saeidi Marco Quirion 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第1期72-87,共16页
The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resista... The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resistance. This capacity is evaluated using Kirsten's index, which was initially developed to evaluate the excavatability of earth materials. For rocky material, this index is determined according to certain geomechanical factors related to intact rock and rock mass, such as compressive strength of intact rock, rock block size, discontinuity shear strength and relative block structure. To quantify the relative block structure, Kirsten(1982) developed a mathematical expression that accounts for the shape and orientation of the blocks relative to the direction of flow. Kirsten's initial concept for assessing the relative block structure considers that the geological formation is mainly fractured by two joint sets forming an orthogonally fractured system. An adjusted concept is proposed to determine the relative block structure when the fractured system is non-orthogonal where the angle between the planes of the two joint sets is greater or less than 90°. An analysis of the proposed relative block structure rating shows that considering a non-orthogonally fractured system has a significant effect on Kirsten's index and, as a consequence, on the assessment of the hydraulic erodibility of rock. 展开更多
关键词 Fractured ROCK DIP angle DIP direction JOINT SPACING RELATIVE block structure Hydraulic ERODIBILITY of ROCK Annandale’s method Kirsten’s index
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