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ANALYSIS OF UN-COINCIDE COORDINATE ERROR IN SINGLE-AXIS ROTATING FIBER OPTIC STRAP-DOWN INERTIAL NAVIGATION SYSTEM 被引量:3
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作者 张玲 赖际舟 +1 位作者 刘建业 吕品 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第2期199-205,共7页
The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system(SINS) is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides ... The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system(SINS) is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides the enhanced property of SINS when using the same-leveled inertial measurement units. Then, the rotating struc- ture modification is derived and augmented to resolve the un-modulated error-accumulated problem. As the insuf- ficient machine processing, the horizontal and the vertical errors on the machine surface are inevitable, and the in- volved coordinates are difficult to get the exact coincident. So, two major kinds of coordinate situation are stud- ied. The equivalent error models on gyro and acceleration outputs are built for each situation, and the impact is analyzed for compensation. The part of attitude and position error models caused by the built angle-rate error is established to calculate the un-eoincident impact. Considering these conditions of different gyro accuracy and mo- tion states simultaneously, numerical simulations are implemented. Results indicate that the SINS modulation ac- curacy is seriously affected by the combined factors on gyro accuracy and motion conditions. 展开更多
关键词 rotational molding modulation machine processing surface horizontal and vertical error un-coinci-dent impact
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Irregular seismic data reconstruction based on exponential threshold model of POCS method 被引量:16
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作者 高建军 陈小宏 +2 位作者 李景叶 刘国昌 马剑 《Applied Geophysics》 SCIE CSCD 2010年第3期229-238,292,293,共12页
Irregular seismic data causes problems with multi-trace processing algorithms and degrades processing quality. We introduce the Projection onto Convex Sets (POCS) based image restoration method into the seismic data... Irregular seismic data causes problems with multi-trace processing algorithms and degrades processing quality. We introduce the Projection onto Convex Sets (POCS) based image restoration method into the seismic data reconstruction field to interpolate irregularly missing traces. For entire dead traces, we transfer the POCS iteration reconstruction process from the time to frequency domain to save computational cost because forward and reverse Fourier time transforms are not needed. In each iteration, the selection threshold parameter is important for reconstruction efficiency. In this paper, we designed two types of threshold models to reconstruct irregularly missing seismic data. The experimental results show that an exponential threshold can greatly reduce iterations and improve reconstruction efficiency compared to a linear threshold for the same reconstruction result. We also analyze the anti- noise and anti-alias ability of the POCS reconstruction method. Finally, theoretical model tests and real data examples indicate that the proposed method is efficient and applicable. 展开更多
关键词 Irregular missing traces seismic data reconstruction POCS threshold model.
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3D simultaneous seismic data reconstruction and noise suppression based on the curvelet transform 被引量:8
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作者 张华 陈小宏 张落毅 《Applied Geophysics》 SCIE CSCD 2017年第1期87-95,190,共10页
Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data recon... Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data reconstruction methods are not ideal for noisy data. In this paper, we choose the multiscale and multidirectional 2D curvelet transform to perform simultaneous data reconstruction and noise suppression of 3D seismic data. We introduce the POCS algorithm, the exponentially decreasing square root threshold, and soft threshold operator to interpolate the data at each time slice. A weighing strategy was introduced to reduce the reconstructed data noise. A 3D simultaneous data reconstruction and noise suppression method based on the curvelet transform was proposed. When compared with data reconstruction followed by denoizing and the Fourier transform, the proposed method is more robust and effective. The proposed method has important implications for data acquisition in complex areas and reconstructing missing traces. 展开更多
关键词 curvelet transform data reconstruction three-dimensional denoizing projections-onto-convex-set algorithm
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Variation and Influence Factors of Yield Gravity Center of Flue-cured Tobacco in Hunan
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作者 邓文 周路阔 +5 位作者 谭杰扬 刘英 祝琪雅 王剑 朱雅玲 黄振国 《Agricultural Science & Technology》 CAS 2017年第9期1770-1776,共7页
The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields ... The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields of flue-cured tobacco in various areas in Hunan were mainly of the growing with fluctuation type. The yield gravity centers in the whole province and eastern, southern and western Hunan tobacco-growing areas overall moved in the north by west, south by west, west by south, and south by east directions, respectively; and the movements in the south-north direction were in order of eastern Hunan tobacco-growing area 〉whole province 〉western Hunan tobacco-growing area 〉southern Hunan tobacco-growing area, and the movements inthe east-west direction showed an order of eastern Hunan tobecco-growing area〉western Hunan tobacco-growing area〉whole province〉 southern Hunan tobacco-growing area. The main influence factors of the coordinates of the longitudes and the latitudes differed. The main influence factor was planting area in most cities or counties in the whole province, and was per unit area yield in a few cities or counties. It is advised to construct the "one main body and two wings" development pattern of flue-cured tobacco production in Hunan with southern Hunan tobacco-growing area as the main body and western and eastern Hunan tobacco-growing areas as the two wings. 展开更多
关键词 Flue-cured tobacco Yield gravity nan
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DETERMINATION OF UNKNOWN CAMERA PARAMETERS FOR THE PERSPECTIVE IMAGES
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作者 昂海松 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第2期95+91-94,共5页
To obtain an accurate 3 D object configuration from images,the essential perspective characteristics must be considered. Several new inverse transformation relations of the perspective image lines are given. Utiliz... To obtain an accurate 3 D object configuration from images,the essential perspective characteristics must be considered. Several new inverse transformation relations of the perspective image lines are given. Utilizing the analytic transformation relations, an optimization procedure for obtaining the unknown camera parameters of images is presented in this paper. A 3 D reproduction method and examples are introduced. 展开更多
关键词 perspective projection optimization perspective image 3 D reproduction
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NEW SHADOWED C-MEANS CLUSTERING WITH FEATURE WEIGHTS 被引量:2
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作者 王丽娜 王建东 姜坚 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第3期273-283,共11页
Partition-based clustering with weighted feature is developed in the framework of shadowed sets. The objects in the core and boundary regions, generated by shadowed sets-based clustering, have different impact on the ... Partition-based clustering with weighted feature is developed in the framework of shadowed sets. The objects in the core and boundary regions, generated by shadowed sets-based clustering, have different impact on the prototype of each cluster. By integrating feature weights, a formula for weight calculation is introduced to the clustering algorithm. The selection of weight exponent is crucial for good result and the weights are updated iteratively with each partition of clusters. The convergence of the weighted algorithms is given, and the feasible cluster validity indices of data mining application are utilized. Experimental results on both synthetic and real-life numerical data with different feature weights demonstrate that the weighted algorithm is better than the other unweighted algorithms. 展开更多
关键词 fuzzy C-means shadowed sets shadowed C-means feature weights cluster validity index
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An electrophoretic display driving waveform based on improvement of activation pattern 被引量:2
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作者 易子川 白鹏飞 +2 位作者 王利 张晓 周国富 《Journal of Central South University》 SCIE EI CAS 2014年第8期3133-3137,共5页
Electrophoretic display(EPD) technology has become one of the main supporting pillars of the electronic paper display industry.Despite its benefits,the EPD technology suffers from several disadvantages such as non-fix... Electrophoretic display(EPD) technology has become one of the main supporting pillars of the electronic paper display industry.Despite its benefits,the EPD technology suffers from several disadvantages such as non-fixed threshold voltage value for gray scale display.In addition,the display has to repeatedly refresh between white and black states to eliminate ghost image when it needs to update a new image.The traditional driving waveform for the EPD includes four stages: erasing the original image,resetting to black state,clearing to white state,and writing a new image.A flicker can be found when transferring between two adjacent stages.A new driving waveform based on the improvement of activation pattern is proposed to weaken the ghost image and reduce the flicker.Experimental results show that the proposed driving waveform could weaken the ghost image effectively and reduce the number of flickers by 50%.Compared with the traditional driving waveform,the driving waveform of this work has a better performance. 展开更多
关键词 electrophoretic display driving waveform ghost image FLICKER
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Characteristics of Bronchial Arterial Reconstruction of Lung Cancer and the Clinical Significance
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作者 刘吉福 李京雨 +2 位作者 田玉旺 武姗姗 刘明 《The Chinese-German Journal of Clinical Oncology》 CAS 2003年第4期224-226,252,共4页
Objective: To study vascular characteristics of bronchial arterial reconstruction for lung cancer in relation to patient’s prognosis.Methods: According to the International Staging System for Lung Cancer, bronchial a... Objective: To study vascular characteristics of bronchial arterial reconstruction for lung cancer in relation to patient’s prognosis.Methods: According to the International Staging System for Lung Cancer, bronchial arteriography was performed in 16 patients with stage III a , 42 patients with stage III b lung cancer before bronchial arterial infusion (BAI) of chemotherapy. Angiograms was read by radiologists and analyzed by real-multicolour picture system. All patients were followed up and the data were collected.Results: The common findings of angiographic vessels were variable distending, hypervascularity with shunting as net, and extravasation of contrast, light or dense staining in the regions of the tumors for all patients. Radial growth vessels in pericancer were found in 30 patients, including 20 cases (66.7%) of small cell lung cancer (SCLC), 7 cases (23.3%) of adenocarcinoma, 3 cases (10%) of squamous carcinoma; a thick circular vessels in pericancer in 16 patients: both characteristics above were seen in 5 cases. Hematogenous dissemination was found in 19 of 30 patients (63.3%) with radial growth vessels in pericancer; lymphatic spread (supraclavicular nodes) in 3 of 30 (10%); local recurrences in 2 of 30 (6.7%) 6 and 30 months respectively after curable resection. Hematogenous dissemination was found in 2 of 28 patients (7.1%) without radial growth vessels in pericancer during the period of follow-up. There was significant difference in the rate of hematogenous dissemination in two groups (P<0.01).Conclusion: Radial growth vessels at pericancer for bronchial arteriography of lung cancer was an important sign of high rate of hematogenous dissemination and lymphatic spread. Key words lung cancer - angiography - metastasis 展开更多
关键词 lung cancer ANGIOGRAPHY METASTASIS
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The impact of tourism on soils in Zhangjiajie World Geopark 被引量:3
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作者 石强 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第2期167-170,共4页
The soil hardness, soil water content and soil bulk density along the trails of six scenic spots in the Zhangjiajie World Geopark were measured and analyzed, and the integrated effects of tourism trampling on soils we... The soil hardness, soil water content and soil bulk density along the trails of six scenic spots in the Zhangjiajie World Geopark were measured and analyzed, and the integrated effects of tourism trampling on soils were evaluated for each scenic spots by calculating its soil impact indexes (SII) in the park. The results indicated that visitors' activities caused a serious influence on the soil in the park, especially in the two most used scenic spots-- Yellowstone Village and Gold Whip Stream. The impact of tourism on soil mainly occurred within 3 m along the trails. The impact shapes are classified into six type as single-sided node type, double-sided node type, cross node type, single-sided linkage type, double-sided linkage type and short-cut linkage type. Of six types of impact shapes, the single-sided node type and double-sided type were dominant. The average water contents of soil for six scenic spots at sample areas of 1 m, 2 m and 3 m from trial is 36.6%, 24.5% and 2.2% lower than that of the control area, respectively. The average soil hardness for six scenic spots at 1m, 2 m, and 3m from the trails tramped increased 167.9%, and 122.2%, and 15.8%, respectively, compared with the control area. Soil bulk density increased 26.5% at 1 m and 20.9% at 2 m from the trails. The main countermeasures for reducing the range and extent of tourism impact on soil are discussed. 展开更多
关键词 TOURISM Zhangjiajie World Geopark Tourism impact Impact shapes Soil impact indexes Soil bulk density Soil hardness
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SPEEDING-UP RE-SAMPLED ALGORITHM IN RAY CASTING VOLUME RENDERING OF MEDICAL IMAGES
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作者 陶玲 王惠南 田芝亮 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第1期52-58,共7页
Ray casting algorithm can obtain a better quality image in volume rendering, however, it exists some problems, such as powerful computing capacity and slow rendering speed. How to improve the re-sampled speed is a key... Ray casting algorithm can obtain a better quality image in volume rendering, however, it exists some problems, such as powerful computing capacity and slow rendering speed. How to improve the re-sampled speed is a key to speed up the ray casting algorithm. An algorithm is introduced to reduce matrix computation by matrix transformation characteristics of re-sampling points in a two coordinate system. The projection of 3-D datasets on image plane is adopted to reduce the number of rays. Utilizing boundary box technique avoids the sampling in empty voxel. By extending the Bresenham algorithm to three dimensions, each re-sampling point is calculated. Experimental results show that a two to three-fold improvement in rendering speed using the optimized algorithm, and the similar image quality to traditional algorithm can be achieved. The optimized algorithm can produce the required quality images, thus reducing the total operations and speeding up the volume rendering. 展开更多
关键词 volume rendering ray casting algorithm acceleration algorithm re-sampled algorithm
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Measurement of a Three-dimensional Gas Temperature Field with Holographic Interferometry 被引量:2
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作者 CHEN Shaohua(Yibin Teacher’s College, Yibin 644007, CHN)ZHAO Xuxin HUANG Suyi SHI Dufang(Huazhong University of Science and Technology, Wuhan 430074, CHN) 《Semiconductor Photonics and Technology》 CAS 1996年第1期72-78,共7页
It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant t... It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant to temperature or density. In this paper, a new multidirectional holographic interferometric system is built, and two kinds of image reconstruction algorithms are introduced and an automatic image processing system of interferogram is designed. A three dimentsional asymmetric gas flow field above a combustor is expertmentally investigated with holographic interferometry. The reconstructed temperatures are similar to those measured with a thermocouple. 展开更多
关键词 Optical Tomography Orthographic Holography Reconstruction Algorithm Image Processing Temperature Measurement
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Does antioxidant therapy influence every aspect of quality of life?
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作者 Tomasz Stefaniak Ad Vingerhoets Zbigniew Sledzinski 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第19期2441-2442,共2页
To present problems that might severely impact the conclusions drawn by the authors of an article on antioxidant treatment in chronic pancreatitis(World J Gastroenterol 2010;16:4066-4071).We analyzed and discussed thi... To present problems that might severely impact the conclusions drawn by the authors of an article on antioxidant treatment in chronic pancreatitis(World J Gastroenterol 2010;16:4066-4071).We analyzed and discussed this paper by Shah et al,and found that promising as it is,this study has some methodological shortcomings,such as:cross-sectional nature of the study,lack of initial evaluations of quality of life and regular follow-ups to determine the dynamics and real directions of changes in quality of life.We therefore concluded that the results of the study by Shah et al are biased and,although very promising,should not be considered as scientifically relevant. 展开更多
关键词 Chronic pancreatitis Quality of life Metho-dology ANTIOXIDANTS
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Impacts of Social and Demographic Factors on Residents' Subjective Well-being in Rural China 被引量:3
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作者 Wang Jian Meng Qingyue +3 位作者 Winnie Yip Sun Qiang Qu Jiangbin Jia Liying 《Chinese Journal of Population,Resources and Environment》 2010年第1期81-87,共7页
The objective of social development is to construct a harmonious society.In China,the key to a harmonious society is the happiness of more than 900 million farmers living in the rural areas.This study aimed to measure... The objective of social development is to construct a harmonious society.In China,the key to a harmonious society is the happiness of more than 900 million farmers living in the rural areas.This study aimed to measure rural residents' subjective well-being(SWB) through the day reconstruction method,as well as to analyze SWB's influencing factors through a variety of statistical methods.The results showed that the average U index was 12.79%,indicating that respondents were unhappy 12.79% of the time.Twenty-seven percent of the population had a U index greater than 0,with the average value being 47%,indicating that these people were unhappy 47% of the time.The study also found that SWB varied according to the characteristics of the respondents.Logistic regression analysis showed that social and demographic factors,including age,education,county,household size,generation number,per capita income,migration status and social networking,which significantly affected rural residents' SWB.The size of the impact varied with the different factors. 展开更多
关键词 rural residents subjective well-being day reconstruc-tion method social and demographic factors
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Rapid Texture Mapping from Image Sequences for Building Geometry Model 被引量:1
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作者 ZHANGZuxun WUJun ZHANGJianqing 《Geo-Spatial Information Science》 2003年第3期8-15,31,共9页
An effective approach, mapping the texture for building model based on the digital photogrammetric theory, is proposed. The easily-acquired image sequences from digital video camera on helicopter are used as texture r... An effective approach, mapping the texture for building model based on the digital photogrammetric theory, is proposed. The easily-acquired image sequences from digital video camera on helicopter are used as texture resource, and the correspondence between the space edge in building geometry model and its line feature in image sequences is determined semi-automatically. The experimental results in production of three-dimensional data for car navigation show us an attractive future both in efficiency and effect. 展开更多
关键词 image sequences video camera on helicopter 3D reconstruction texture mapping digital photogrammetry
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A WEIGHTED ITERATIVE METHOD FOR ROBUST SELF-CALIBRATION
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作者 Liu Shigang Wu Chengke Tang Li Jia Jing 《Journal of Electronics(China)》 2006年第5期713-717,共5页
A robust self-calibration method is presented, which can efficiently discard the outliers based on a Weighted Iteration Method (WIM). The method is an iterative process in which the projective reconstruction is obtain... A robust self-calibration method is presented, which can efficiently discard the outliers based on a Weighted Iteration Method (WIM). The method is an iterative process in which the projective reconstruction is obtained based on the weights of all the points, whereas the weights are defined in inverse proportion to the re- ciprocal of the re-projective errors. The weights of outliers trend to zero after several iterations, and the accu- rate projective reconstruction is determined. The location of the absolute conic and the camera intrinsic pa- rameters are obtained after the projective reconstruction. The theory and experiments with both simulate and real data demonstrate that the proposed method is very efficient and robust. 展开更多
关键词 Weight iteration Self calibration Projective reconstruction
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The Dual Effects of Global Value Chain Embeddedness on Chinese Exports’ Technological Sophistication
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作者 刘维林 李兰冰 刘玉海 《China Economist》 2015年第1期58-72,共15页
This paper develops a framework for the assessment of global value chain embeddedness based on the dual structure of product embeddedness and functional embeddedness and provides a theoretical demonstration of the dua... This paper develops a framework for the assessment of global value chain embeddedness based on the dual structure of product embeddedness and functional embeddedness and provides a theoretical demonstration of the dual effects of the level, structure and the value sources of global value chain embeddedness on export technology sophistication. From there, the paper carries out an estimation of non-competitive input- output table using quadratic optimized algorithm with differentiation between processing trade and general trade to arrive at various indicators of foreign value-added ratio that reflect the level of global value chain embeddedness. On this basis, the panel econometric model for 27 manufacturing sectors of China between 2001 and 2010 is employed to test the effect of foreign value-added ratio on the technology sophistication of manufacturing export. Our research indicates that by taking part in division of labor in the global value chain and acquiring foreign intermediate inputs, China's manufacturing sector has increased its export technology sophistication. It also indicates that, compared with such inputs as raw materials and parts and components, service input has great contributions to technology improvement. With the direct contributions of foreign value-added under control, the foreign value-added from developed countries has a restrictive effect on the R&D activities of export manufacturing, which gives rise to the one-way technology reliance on dominant enterprises of the value chain and the "low-end lock-up" effect; meanwhile, the method of embeddedness that takes advantage of the foreign value-added of other countries is more dependent on the indigenous R&D capacity of export enterprises and thus more favorable to the improvement of export technology sophistication. 展开更多
关键词 global value chain foreign value-added export technology sophistication vertical professionalization
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Reconstruction of Tomographic Images from a Few Views by New Maximum Entropy Approach
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作者 CHEN Shao-hua (College of Phys. & Electron. Techn., Hubei University, Wuhan 430062, C HN) 《Semiconductor Photonics and Technology》 CAS 2000年第4期200-203,共4页
A new algorithm for the reconstruction of tomographic images from a few views is presented. A variable metric method is used to solve the unconstrained optimization problem which resulted from the analysis by use of t... A new algorithm for the reconstruction of tomographic images from a few views is presented. A variable metric method is used to solve the unconstrained optimization problem which resulted from the analysis by use of the maximum ent ropy formalism. The numerical simulation is used to study the reconstruction eff ect on the different asymmetric functions. The results show that the reconstruct ion accuracy is satisfactory. 展开更多
关键词 Maximum entropy Tomographic reconstruction ALGORITHM
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A Numerical Study of the Urban Intensity Effect on Fog Evolution in the Beijing-Tianjin-Hebei Region 被引量:5
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作者 LIANG Zhao-Ming GAO Shou-Ting SUN Ji-Song 《Atmospheric and Oceanic Science Letters》 2012年第3期240-245,共6页
The influence of urban intensity on fog evolution in the Beijing-Tianjin-Hebei (BTH) region (China) is investigated numerically with the the Weather Research and Forecasting (WRF) model coupled with the urban canopy p... The influence of urban intensity on fog evolution in the Beijing-Tianjin-Hebei (BTH) region (China) is investigated numerically with the the Weather Research and Forecasting (WRF) model coupled with the urban canopy parameterization-building energy model (UCP- BEM) urban physics scheme. The experiments were designed with a focus on the influence of different urban intensities, which are represented by a different fractional coverage of natural land, buildings, and energy consumption inside buildings in an urban environment. The results of this study indicate that urban areas notably influence fog evolution when natural land is reduced to a small fraction (e.g., less than 10%). Developed land changes fog evolution through urban effects. Higher urban intensity (HUI) generally results in warmer temperatures and lower wind speeds throughout the day, while inhibiting morning specific humidity loss and afternoon specific humidity gain because of the HUI effect on surface heat flux, surface roughness, and surface moisture flux. HUI leads to later and weaker liquid water content formation, with a higher liquid water content base, primarily due to its effect on near surface temperatures. This finding implies that HUI may inhibit the conditions for fog formation. In addition, urban areas with equal natural and developed land coverage seem to greatly enhance the upward surface moisture flux, which is attributed to the combination of a relatively large potential evaporation on developed land and an ample moisture supply from natural land. As a result, the specific humidity increases in the afternoon. 展开更多
关键词 numerical study urban intensity effect FOG the Beijing-Tianjin-Hebei region
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Earthquake-Affected Time-Space Domain, Recurrence Interval and Effective Preparation Time of Earthquakes
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作者 Wang Shengzu and Zhang ZongchunInstitute of Geology & Laboratory of Tectonophysics, China Seismological Bureau, Beijing 100029, China 《Earthquake Research in China》 2002年第4期380-395,共16页
The study shows that earthquake-affected time-space domain (ETSD), i.e. a time-space range in which strong earthquakes are unable to occur owing to the influence of a prior earthquake occurring, shows a hyperbolic mar... The study shows that earthquake-affected time-space domain (ETSD), i.e. a time-space range in which strong earthquakes are unable to occur owing to the influence of a prior earthquake occurring, shows a hyperbolic margin curve in the t(time)-r(distance) coordinate plane, which has a maximum affected radius r 0 at t=0 and a maximum influence time t 0 (i.e. the in-situ recurrence interval of earthquakes) at r=0. Based on the time-distance distributions of posterior earthquakes relative to prior ones in the regions of North China, Northwest China, Qinghai-Xizang (Tibet) plateau and Southwest China, the optimized and 90%-confidence margin curves are estimated using optimization and statistical analysis methods. This indicates that the concept and method of ETSD with 3-dimension (time-distance-magnitudes) instead of those of “recurrence interval" with 1-dimension (time) or 2-dimension (time-magnitude) provides a new approach to understanding the fluctuation of seismic activities, estimating the effective earthquake-preparation time of potential hypocenters, and therefore improving the medium- and long-term prediction of strong earthquakes. 展开更多
关键词 Earthquake-affected time-space domain Recurrence interval Affected radius Effective earthquake-preparation time
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Analysis of Object Depth Effects on Accuracy of Dimensional Shape in X and Y Directions Using Single Non-metric Image
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作者 Tarek M.A. ZHU Qing 《Geo-Spatial Information Science》 2007年第4期269-275,共7页
In general, to reconstruct the accurate shape of buildings, we need at least one stereomodel (two photographs) for each building. In most cases, however, only a single non-metric photograph is available, which is us... In general, to reconstruct the accurate shape of buildings, we need at least one stereomodel (two photographs) for each building. In most cases, however, only a single non-metric photograph is available, which is usually obtained either by an amateur, such as a tourist, or from a newspaper or a post card. To evaluate the validity of 3D reconstruction from a single non-metric image, this study analyzes the effects of object depth on the accuracy of dimensional shape in X and Y directions using a single non-metric image by means of simulation technique, as this was considered to be, in most cases, a main source of data acquisition in recording and documenting buildings. 展开更多
关键词 SINGLE non-metric image reconstruction object depth ACCURACY dimensional shape
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