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Search Results: 1 - 10 of 104204 matches for " Zhang Linbo "
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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.

Evaluation of Major Factors Affecting Spatial Resolution of Gamma-Rays Camera  [PDF]
Hongwei Xie, Jianhua Zhang, Jinchuan Chen, Faqiang Zhang, Linbo Li, Jianming Qi, Yanyun Chu
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2013, DOI: 10.4236/jasmi.2013.34029
Abstract:

The spatial resolution of the gamma-rays camera was measured on a60Co gamma-rays source with edge method. The gamma-rays camera is consisting with rays-fluorescence convertor, optical imaging system, MCP image intensifier, CCD camera, electronic control system and other devices, and is mainly used in the image diagnostics of the intense pulse radiation sources [1]. Due to the relatively big quantum detective efficiency (DQE) and quantum gain of the gamma-rays, etc., the experimental data were processed by averaging multiple images and fitting curves. According to the experimental results, the spatial resolution MTF (modulation transfer function) at the 10% intensity was about 2lp/mm. Meanwhile, because of the relatively big dispersion effects of the fluorescence transmissions in the scintillator and the optical imaging system, the maximal single-noise ratio (SNR) of the camera was found to be about 5:1. In addition, the spatial resolution of the camera was measured with pulse X-rays with 0.3MeV in average energy and exclusion of the effects of secondary electrons from consideration. Accordingly, the spatial resolution MTF at the 10% intensity was about 5lp/mm. This could be an additional evidence to verify the effects of secondary electrons induced by the 1.25MeV gamma-rays in the scintillator upon the spatial resolution. Based on our analysis, the dispersion sizes of the secondary electrons in the scintillator are about 0.4mm-0.6mm. Comparatively, as indicated by the detailed analysis of the spatial resolutions of the MCP image intensifier and CCD devices, both of them have little effect on the spatial resolution of the gamma-rays camera that could be well neglected.

Adaptive Linearized Alternating Direction Method of Multipliers for Non-Convex Compositely Regularized Optimization Problems
Linbo Qiao,Bofeng Zhang,Xicheng Lu,Jinshu Su
- , 2017, DOI: 10.23919/TST.2017.7914204
Abstract: We consider a wide range of non-convex regularized minimization problems, where the non-convex regularization term is composite with a linear function engaged in sparse learning. Recent theoretical investigations have demonstrated their superiority over their convex counterparts. The computational challenge lies in the fact that the proximal mapping associated with non-convex regularization is not easily obtained due to the imposed linear composition. Fortunately, the problem structure allows one to introduce an auxiliary variable and reformulate it as an optimization problem with linear constraints, which can be solved using the Linearized Alternating Direction Method of Multipliers (LADMM). Despite the success of LADMM in practice, it remains unknown whether LADMM is convergent in solving such non-convex compositely regularized optimizations. In this research, we first present a detailed convergence analysis of the LADMM algorithm for solving a non-convex compositely regularized optimization problem with a large class of non-convex penalties. Furthermore, we propose an Adaptive LADMM (AdaLADMM) algorithm with a line-search criterion. Experimental results on different genres of datasets validate the efficacy of the proposed algorithm.
A Study of a Method to Assess the Purity of Sorted Bovine Semen Using Rapid Single-Sperm Sexing PCR
Dong Wang,Huabin Zhu,Jiaming Guo,Bo Lin,Linbo Zhang,Haisheng Hao,Weihua Du,Xueming Zhao
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.750.756
Abstract: Sort reanalysis using flow cytometry is the most common method for determining the purity of X or Y enriched semen. The high cost of this technique (including the required expensive, proprietary machine) limits efforts to improve the technique and to promote develop applications for the sorted semen. In this study, the sperm sex (the presence of the X or Y chromosome) was identified by both rapid PCR and flow cytometry reanalysis. The rapid PCR results showed that the percentages of X and Y sperm were 48 and 52% in unsorted semen, 92 and 8% in X-enriched semen and 17 and 83% in Y-enriched semen, respectively. Reanalysis of the DNA content of the sorted samples revealed that the X and Y sperm frequencies were 92 and 8% in X-enriched semen and 15 and 85% in Y-enriched semen, respectively. The sex ratio of unsorted semen analyzed by PCR did not significantly deviate from the expected ratio of 1:1 and there was no significant difference between the sex ratios of sorted semen samples determined by PCR and flow cytometry reanalysis. These results indicate that we have established an effective, reliable and rapid PCR method to verify the purity of sorted semen. This method should contribute greatly to the improvement of sperm sorting techniques and the development of applications for sorted semen.
Analysis of ecosystem degradation and recovery using precipitation use efficiency and NDVI in the headwater catchment of the Yellow River basin
基于植被降水利用效率和NDVI的黄河上游地区生态退化研究

DU Jiaqiang,SHU Jianmin,ZHANG Linbo,
杜加强
,舒俭民,张林波

生态学报 , 2012,
Abstract: The accurate identification of areas of ecosystem degradation and an objective evaluation of the effects of ecological restoration projects is necessary for ecological management and planning at the landscape scale. Ecological degradation and ecological restoration are dynamic equilibrium processes, while degradation must be considered relative to the pristine state of the ecosystem, and need to be analyzed from a time series perspective. Satellite remote sensing is widely used in ecological monitoring and assessment, as it provides extensive coverage, good spatial and temporal continuity and a long time-series dataset. This paper proposes a method for the identification of areas of ecosystem degradation and ecosystem recovery using long time-series satellite remote sensing and precipitation data, which are integrated into trend analyses of the precipitation use efficiency (PUE) and a normalized difference vegetation index (NDVI). The PUE is calculated as the ratio of cumulative NDVI to precipitation. Significantly reduced PUE and NDVI values indicate that ecological degradation is occurring, while increasing PUE and NDVI values indicate ecological recovery. This method was applied to the headwater catchment of the Yellow River basin in China using Advanced Very High Resolution Radiometer NDVI data from 1982 to 2006 and meteorological data from the same time period. The annual PUE value was calculated using the cumulative NDVI and precipitation in the growing season for each pixel. A comparative analysis of the trends in PUE and NDVI was undertaken to detect areas of ecosystem degradation and restoration. The results show that: (i) The average PUE and NDVI values across the region increased slightly, and the area undergoing ecosystem rehabilitation during 1982-2006 comprised more than 80% of the study area. (ii) The degraded area, with significantly negative trends in the PUE and NDVI values, mainly occurred in the region surrounding Maduo County, Zaling and Eling lakes and Longyangxia Reservoir. Significant ecosystem recovery was found in southeast part of the study area, where strong positive trends were identified in the PUE and NDVI values. (iii) The areas with ecosystem degradation and restoration detected in this study were consistent with the current grassland degradation situation in the headwater catchment of the Yellow River basin, indicating that this method is reliable and could be applied to the evaluation of the regional ecosystem. (iv) The PUE value is partially dependent on changes in the precipitation, so false ecosystem degradation or ecosystem recovery trends may be identified caused by rapid increases and decreases, respectively, in the precipitation rate. For example, a decrease PUE in Xining City was partly caused by increased precipitation. Evaluating the trends in both PUE and NDVI may avoid the errors caused by using PUE as the only factor when evaluating ecosystem degradation and recovery. This method is simple, feasible
The Application of Multigrid Method in the Adaptive Mesh of Acceleration Generation
多重网格法在加速自适应网格生成中的应用

Liu Zhuo,Zeng Qingcun,Zhang Linbo,
刘卓
,曾庆存,张林波

大气科学 , 1998,
Abstract: The multigrid method which was developed in the 1970s is a powerful tool to accelerate the convergence of iterative It uses different mesh density to eliminate the different frequency component of errors, which accelerate the convergence of iterative It possess of the advantages with fast convergent speed, high convergent accurate and saving CPU Multigrid method was applied to accelerate the generation of adaptive mesh in this paper Experiments show that the multigrid method raises efficiency with more than twenty times compared with single grid
Parallel Algorithm Design on Some Distributed Systems
Sun Jiachang,Chi Xuebin,Cao Jianwen,
Sun Jiachang
,Chi Xuebin,Cao Jianwen,Zhang Linbo

计算机科学技术学报 , 1997,
Abstract: Some testing results on DAWNING-1000, Paragon and workstation cluster are described in this paper. On the home-made parallel system DAWNING-1000 with 32 computational processors, the practical performance of 1.117 Gflops and 1.58 Gflops has been measured in solving a dense linear system and doing matrix multiplication, respectively. The scalability is also investigated. The importance of designing efficient parallel algorithms for evaluating parallel systems is emphasized.
多重网格法在加速自适应网格生成中的应用
刘卓 Liu Zhuo,曾庆存 Zeng Qingcun,张林波 Zhang Linbo
大气科学 , 1998, DOI: 10.3878/j.issn.1006-9895.1998.02.07
Abstract: 多重网格法是70年代以来发展起来的用于加速迭代收敛的一种行之有效的方法,它通过采用不同疏密的网格距来“消除”不同频率范围内的误差分量的办法,加速了迭代的收敛速度,具有收敛速度快,收敛精度高以及节省CPU时间等特点。将其用于台风路径预报的自适应网格的生成,试验表明,多重网格法比单重网格可提高效率达20多倍。
Fast Tensor Principal Component Analysis via Proximal Alternating Direction Method with Vectorized Technique  [PDF]
Haiyan Fan, Gangyao Kuang, Linbo Qiao
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.81007
Abstract: This paper studies the problem of tensor principal component analysis (PCA). Usually the tensor PCA is viewed as a low-rank matrix completion problem via matrix factorization technique, and nuclear norm is used as a convex approximation of the rank operator under mild condition. However, most nuclear norm minimization approaches are based on SVD operations. Given a matrix \"\" , the time complexity of SVD operation is O(mn2), which brings prohibitive computational complexity in large-scale problems. In this paper, an efficient and scalable algorithm for tensor principal component analysis is proposed which is called Linearized Alternating Direction Method with Vectorized technique for Tensor Principal Component Analysis (LADMVTPCA). Different from traditional matrix factorization methods, LADMVTPCA utilizes the vectorized technique to formulate the tensor as an outer product of vectors, which greatly improves the computational efficacy compared to matrix factorization method. In the experiment part, synthetic tensor data with different orders are used to empirically evaluate the proposed algorithm LADMVTPCA. Results have shown that LADMVTPCA outperforms matrix factorization based method.
Interactions of miR-34b/c and TP53 Polymorphisms on the Risk of Intracranial Aneurysm
Lijuan Li,Xiutian Sima,Peng Bai,Lushun Zhang,Hong Sun,Weibo Liang,Jianxing Liu,Lin Zhang,Linbo Gao
Clinical and Developmental Immunology , 2012, DOI: 10.1155/2012/567586
Abstract: Several lines of evidence indicate that inflammatory processes play a key role in the happening and development of intracranial aneurysm (IA). Recently, polymorphisms in the TP53 gene were shown to be associated with inflammation and inflammatory disease. The aim of this study was to investigate the interactions of miR-34b/c and TP53 Arg72-Pro polymorphisms on the risk of IA in a Chinese population. A total of 590 individuals (including 164 patients with IA and 426 controls) were involved in this study. The polymorphisms (i.e., miR-34b/c rs4938723 and TP53 Arg72-Pro) were genotyped by polymerase chain reaction-restriction fragment length polymorphism assay and DNA sequencing. We found that the CC genotype of miR-34b/c rs4938723 was significantly associated with a decreased risk of IA compared with the TT genotype. Moreover, a significant gene interaction of the carriers with the combined genotypes of miR-34b/c rs4938723CC and TP53 Arg72Pro CG/CC/GG had a decreased risk of IA, compared with those carrying miR-34b/c rs4938723CT/TT
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