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Search Results: 1 - 10 of 43703 matches for " Jianhua Xu "
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K-cluster-valued compressive sensing for imaging
Xu Mai,Lu Jianhua
EURASIP Journal on Advances in Signal Processing , 2011,
Abstract: The success of compressive sensing (CS) implies that an image can be compressed directly into acquisition with the measurement number over the whole image less than pixel number of the image. In this paper, we extend the existing CS by including the prior knowledge of K-cluster values available for the pixels or wavelet coefficients of an image. In order to model such prior knowledge, we propose in this paper K-cluster-valued CS approach for imaging, by incorporating the K-means algorithm in CoSaMP recovery algorithm. One significant advantage of the proposed approach, rather than the conventional CS, is the capability of reducing measurement numbers required for the accurate image reconstruction. Finally, the performance of conventional CS and K-cluster-valued CS is evaluated using some natural images and background subtraction images.
The relationship between vegetation coverage and climate elements in Yellow River Basin, China
Qin Nie,Jianhua Xu
PeerJ , 2015, DOI: 10.7287/peerj.preprints.153v1
Abstract: The paper examined the vegetation coverage dynamic and its response to climate elements in Yellow River Basin from 1998 to 2008 by an integrated approach made from series methods including correlation analysis, wavelet analysis, and wavelet regression analysis. The main findings are as follows: (1) Vegetation coverage exhibited significant, positive correlation with temperature and precipitation, but negative correlation with sunshine hours and relative humidity at some sites. The correlation between NDVI and precipitation is closest, followed respectively by temperature, relative humidity, and sunshine hours. Precipitation and temperature are the two major climate elements affecting vegetation coverage dynamics. (2) The vegetation coverage dynamics reflected by NDVI time series presented nonlinear variations that depended on the time-scale. Precipitation and temperature both presented nonlinear variations that were morphologically similar with those of NDVI. These further supported the close relationship between NDVI and these two climate elements from a new perspective. (3) Although NDVI, temperature, and precipitation revealed nonlinear variations at different time scales, the vegetation coverage showed a significantly, positively linear correlation with temperature and precipitation at all the time scales under examination.
Left Pulmonary Artery Sling Associated with Patent Ductus Arteriosus and Atrial Septal Defect: Evaluation with Multidetector CT  [PDF]
Rukeshman Shakya, Jianhua Liu, Mohit Godar, Qinghai Yuan, Xiaolin Xu
Advances in Computed Tomography (ACT) , 2012, DOI: 10.4236/act.2012.13004
Abstract:

We report a case of left pulmonary artery sling associated with patent ductus arteriosus and atrial septal defect in a 21-month-old child. 256-slice MDCT provides valuable information, such as abnormal origin of the left pulmonary artery, the relationship between pulmonary artery and airway, the diameter of the patent ductus artery and atrial septal defect. The information is helpful in diagnosis, pre-operative evaluation and post-operative follow-up of LPS.

Study of Supper Resolution Processing Methods for Thick Pinhole Image  [PDF]
Hongwei Xie, Faqiang Zhang, Jianhua Zhang, Zeping Xu, Linbo Li
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.42030
Abstract:

An image super resolution reconstruction method was used to improve the spatial resolution of the thick pinhole imaging system and to mitigate the limitations of the image spatial resolution of the hardware of the image diagnostic system. The thick pinhole is usually applied into the diagnostics of the high energy neutron radiation image. Due to the impacts among its energy flux, spatial resolution and effective field of view, in dealing with the large area radiation source, the spatial resolution of the thick pinhole neutron image cannot meet the requirements for high precision modeling of the radiation source image. In this paper, the Lucy-Richardson image super resolution reconstruction method was used to simulate the thick pinhole imaging and super resolution image reconstruction. And the spatial resolution of the image could be increased by over three times after the image super resolution reconstruction. Besides, in dealing with the pseudo-noise, plum blossom shape appeared in the image super resolution reconstruction. The analysis of the source of the pseudo-noise was made based on the simulation of the image reconstruction under various conditions according to the characteristics of the thick pinhole image configuration.

Adaptability of Polymer-Containing Sewage Corrosion Inhibitor  [PDF]
Limei Sun, Chunxi Gao, Wenmiao Gao, Jie Cui, Jianhua Xu
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.67008
Abstract:
The polymer content in the produced water from Tuoliu Station is about 20 mg/L. Cationic imidazoline-type corrosion inhibitor is used to corrosion control of sewage. The corrosion inhibitor can react with the negatively charged materials such as anionic polymer and suspended substance by adsorption and merging to form complex aggregates, so that the suspended solids content increases, resulting in suspended solids content of exported sewage has been high. So a new type of non-ionic corrosion inhibitor has been developed and field trials have been performed. The results show that non-ionic corrosion inhibitor can effectively reduce the suspended solids content of wastewater while ensuring the corrosion rate of wastewater.
Asymptotic optimality and efficient computation of the leave-subject-out cross-validation
Ganggang Xu,Jianhua Z. Huang
Statistics , 2013, DOI: 10.1214/12-AOS1063
Abstract: Although the leave-subject-out cross-validation (CV) has been widely used in practice for tuning parameter selection for various nonparametric and semiparametric models of longitudinal data, its theoretical property is unknown and solving the associated optimization problem is computationally expensive, especially when there are multiple tuning parameters. In this paper, by focusing on the penalized spline method, we show that the leave-subject-out CV is optimal in the sense that it is asymptotically equivalent to the empirical squared error loss function minimization. An efficient Newton-type algorithm is developed to compute the penalty parameters that optimize the CV criterion. Simulated and real data are used to demonstrate the effectiveness of the leave-subject-out CV in selecting both the penalty parameters and the working correlation matrix.
A membrane evolutionary algorithm for DNA sequence design in DNA computing
JianHua Xiao,XingYi Zhang,Jin Xu
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4928-7
Abstract: DNA sequence design has a crucial role in successful DNA computation, which has been proved to be an NP-hard (non-deterministic polynomial-time hard) problem. In this paper, a membrane evolutionary algorithm is proposed for the DNA sequence design problem. The results of computer experiments are reported, in which the new algorithm is validated and out-performs certain known evolutionary algorithms for the DNA sequence design problem.
Studies on inner wall structure of tracheids inTaxus chinensis with resin casting method
Jianhua Xu,Yuxi Hu,Jinxing Lin
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02885986
Abstract: The resin casting method has been applied to studying the inner wall structure of tracheids in normal and compression wood,Taxus chinensis in gymnosperm. Not only the structures which are visible by the conventional method, but also the three-dimensional structures of pits pair in intertracheids unvisualized by the normal way have been observed. Moreover, it is found that there exist many differences in the angle, trend and occurrence of helical thickenings and distribution of warty layers on the inner walls of tracheids in normal and compression wood.
Effects of annealing temperature on the microstructure and hardness of TiAlSiN hard coatings
Xin Wang,JianHua Xu,ShengLi Ma,KeWei Xu
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4237-6
Abstract: TiAlSiN hard coatings were synthesized on high-speed steel using an arc ion enhanced magnetic sputtering hybrid system. The microstructure and hardness of the coatings at different annealing temperatures were explored by means of XRD, TEM, EDAX and Vickers indentation. The as-deposited TiAlSiN coatings were confirmed to be amorphous due to high depositing rate and low deposition temperature during the film growth. The transformation from amorphous to nanocomposites of nano-crystallites and amorphousness were observed after the annealing treatment, the microstructure of TiAlSiN coatings annealed at 800°C and 1000°C were consisted of crystalline hcp-AlN, fcc-TiN and amorphous phase, however, the coatings were only consisted of fcc-TiN and amorphous phase when annealing at 1100°C and 1200°C. Meanwhile, the formation of Al2O3 was detected on the coating surface after annealing at 1200°C and it indicated the excellent oxidation resistance of the TiAlSiN coatings under the present experimental conditions. Furthermore, the average grain size of the TiAlSiN coatings after high temperature annealing even at 1200°C was less than 30 nm and the size increased with the increasing temperature. However, the hardness of the so-deposited coatings with HV0.2N=3300 dramatically decreased with the increase of temperature and reached nearly to the hardness of TiN coatings with HV0.2N=2300.
Remote sensing of spatial patterns of urban renewal using linear spectral mixture analysis: A case of central urban area of Shanghai (1997–2000)
Wenze Yue,XU Jianhua,Jiawei Wu,Lihua Xu
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-0977-8
Abstract: It is very important to integrate remote sensing with urban geography that the spectral mixture analysis technique is applied to urban land cover evolvement and its eco-environmental effect. Urban land cover is mainly composed of complicated artificial materials, which is the key factor to limit the development of the spectral mixture analysis technique. There are two main aspects in which the technique of spectral mixture analysis is applied to urban geography: one is to calculate vegetation fraction; the other is to build quantitative model of the urban impervious surface obtained from the combination between high albedo fraction and low albedo fraction. The technique of spectral mixture analysis is firstly applied to study urban renewal pattern, scale and mode which happened in Shanghai City from 1997 to 2000.
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