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Alteration Information Extraction by Applying Synthesis Processing Techniques to Landsat ETM+Data: Case Study of Zhaoyuan Gold Mines, Shandong Province, China
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作者 刘福江 吴信才 +1 位作者 孙华山 郭艳 《Journal of China University of Geosciences》 SCIE CSCD 2007年第1期72-76,共5页
Satellite remote sensing data are usually used to analyze the spatial distribution pattern of geological structures and generally serve as a significant means for the identification of alteration zones. Based on the L... Satellite remote sensing data are usually used to analyze the spatial distribution pattern of geological structures and generally serve as a significant means for the identification of alteration zones. Based on the Landsat Enhanced Thematic Mapper (ETM+) data, which have better spectral resolution (8 bands) and spatial resolution (15 m in PAN band), the synthesis processing techniques were presented to fulfill alteration information extraction: data preparation, vegetation indices and band ratios, and expert classifier-based classification. These techniques have been implemented in the MapGIS-RSP software (version 1.0), developed by the Wuhan Zondy Cyber Technology Co., Ltd, China. In the study area application of extracting alteration information in the Zhaoyuan (招远) gold mines, Shandong (山东) Province, China, several hydorthermally altered zones (included two new sites) were found after satellite imagery interpretation coupled with field surveys. It is concluded that these synthesis processing techniques are useful approaches and are applicable to a wide range of gold-mineralized alteration information extraction. 展开更多
关键词 alteration information extraction Zhaoyuan gold mines Landsat-7 ETM+ data
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Research and Practice on the Multi-dimensional Course Goal Achievement Evaluation of Software Engineering
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作者 Ying Jiang Hongbin Wang Jiaman Ding 《计算机教育》 2023年第12期265-271,共7页
According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteris... According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteristics of hybrid teaching in Kunming University of Science and Technology.Then a multi-dimensional evaluation system for course goal achievement of software engineering is proposed.The practice’s results show that the multi-dimensional course goal achievement evaluation is helpful to the continuous improvement of course teaching,which can effectively support the evaluation of graduation outcomes. 展开更多
关键词 Software engineering Course goal achievement evaluation MULTI-DIMENSIONAL
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Self-adaptive PID controller of microwave drying rotary device tuning on-line by genetic algorithms 被引量:6
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作者 杨彪 梁贵安 +5 位作者 彭金辉 郭胜惠 李玮 张世敏 李英伟 白松 《Journal of Central South University》 SCIE EI CAS 2013年第10期2685-2692,共8页
The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and wi... The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and with multivariable nonlinear interaction of microwave and materials. The conventional PID control strategy incorporated with optimization GA was put forward to maintain the optimum drying temperature in order to keep the moisture content below 1%, whose adaptation ability included the cost function of optimization GA according to the output change. Simulations on five different industrial process models and practical temperature process control system for selenium-enriched slag drying intensively by using IMDRDWM were carried out systematically, indicating the reliability and effectiveness of control design. The parameters of proposed control design are all on-line implemented without iterative predictive calculations, and the closed-loop system stability is guaranteed, which makes the developed scheme simpler in its synthesis and application, providing the practical guidelines for the control implementation and the parameter design. 展开更多
关键词 industrial microwave DRYING ROTARY device SELF-ADAPTIVE PID controller genetic algorithm ON-LINE tuning SELENIUM-ENRICHED SLAG
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Genome-wide Analysis of MYB Gene Family in Potato Provides Insights into Tissue-specific Regulation of Anthocyanin Biosynthesis 被引量:17
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作者 Yumei Li Jun Liang +5 位作者 Xiangzhi Zeng Han Guo Youwei Luo Philip Kear Shouming Zhang Guangtao Zhu 《Horticultural Plant Journal》 SCIE CSCD 2021年第2期129-141,共13页
The MYB transcription factor is one of the largest gene families in plants,playing an important role in regulating plant growth,development,response to stress,senescence,and especially the anthocyanin biosynthesis.In ... The MYB transcription factor is one of the largest gene families in plants,playing an important role in regulating plant growth,development,response to stress,senescence,and especially the anthocyanin biosynthesis.In this study,A total of 217 MYB genes,including 901R-MYBs,124 R2R3-MYBs,and 3 R1R2R3-MYBs have been identified from the potato genome.The 1R-MYB and R2R3-MYB family members could be divided into 20 and 35 subgroups respectively.Analysis of gene structure and protein motifs revealed that members within the same subgroup presented similar exon/intron and motif organization,further supporting the results of phylogenetic analysis.Potato is an ideal plant to reveal the tissue-specific anthocyanins biosynthesis regulated by MYB,as the anthocyanins could be accumulated in different tissues,showing colorful phenotypes.Five pairs of colored and colorless tissues,stigma,petal,stem,leaf,and tuber flesh,were applied to the transcriptomic analysis.A total of 70 MYB genes were found to be differentially expressed between colored and colorless tissues,and these differentially expressed genes were suspected to regulate the biosynthesis of anthocyanin of different tissues.Co-expression analysis identified numerous potential interactive regulators of anthocyanins biosynthesis,involving 39 MYBs,24 bHLHs,2 WD-repeats,and 29 biosynthesis genes.Genome-wide association study(GWAS)of tuber flesh color revealed amajor signal at the end of Chromosome 10,which was co-localized with reported I gene(StMYB88),controlling tuber peel color.Analyses of DEGs(Differentially Expression Genes)revealed that both StMYB88 and StMYB89 were closely related to regulating anthocyanin biosynthesis of tuber flesh.This work offers a comprehensive overview of the MYB family in potato and will lay a foundation for the functional validation of these genes in the tissue-specific regulation of anthocyanin biosynthesis. 展开更多
关键词 POTATO MYB transcription factor ANTHOCYANIN differentially expressed CO-EXPRESSION tuber flesh
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Effects of RapidEye Imagery's Red-edge Band and Vegetation Indices on Land Cover Classification in an Arid Region 被引量:9
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作者 LI Xianju CHEN Gang +3 位作者 LIU Jingyi CHEN Weitao CHENG Xinwen LIAO Yiwei 《Chinese Geographical Science》 SCIE CSCD 2017年第5期827-835,共9页
Land cover classification(LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidE ye images was eff... Land cover classification(LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidE ye images was effective for vegetation identification and could improve LCC accuracy. However, there has been no investigation of the effects of RapidE ye images' red-edge band and vegetation indices on LCC in arid regions where there are spectrally similar land covers mixed with very high or low vegetation coverage information and bare land. This study focused on a typical inland arid desert region located in Dunhuang Basin of northwestern China. First, five feature sets including or excluding the red-edge band and vegetation indices were constructed. Then, a land cover classification system involving plant communities was developed. Finally, random forest algorithm-based models with different feature sets were utilized for LCC. The conclusions drawn were as follows: 1) the red-edge band showed slight contribution to LCC accuracy; 2) vegetation indices had a significant positive effect on LCC; 3) simultaneous addition of the red-edge band and vegetation indices achieved a significant overall accuracy improvement(3.46% from 86.67%). In general, vegetation indices had larger effect than the red-edge band, and simultaneous addition of them significantly increased the accuracy of LCC in arid regions. 展开更多
关键词 arid region land cover classification RapidEye red-edge band vegetation indices random forest Dunhuang Basin
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Discrimination of Motor Imagery Patterns by Electroencephalogram Phase Synchronization Combined With Frequency Band Energy 被引量:4
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作者 Chuanwei Liu Yunfa Fu +3 位作者 Jun Yang Xin Xiong Huiwen Sun Zhengtao Yu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第3期551-557,共7页
Central nerve signal evoked by thoughts can be directly used to control a robot or prosthetic devices without the involvement of the peripheral nerve and muscles.This is a new strategy of human-computer interaction.A ... Central nerve signal evoked by thoughts can be directly used to control a robot or prosthetic devices without the involvement of the peripheral nerve and muscles.This is a new strategy of human-computer interaction.A method of electroencephalogram(EEG) phase synchronization combined with band energy was proposed to construct a feature vector for pattern recognition of brain-computer interaction based on EEG induced by motor imagery in this paper,rhythm and beta rhythm were first extracted from EEG by band pass filter and then the frequency band energy was calculated by the sliding time window;the instantaneous phase values were obtained using Hilbert transform and then the phase synchronization feature was calculated by the phase locking value(PLV) and the best time interval for extracting the phase synchronization feature was searched by the distribution of the PLV value in the time domain.Finally,discrimination of motor imagery patterns was performed by the support vector machine(SVM).The results showed that the phase synchronization feature more effective in4s-7s and the correct classification rate was 91.4%.Compared with the results achieved by a single EEG feature related to motor imagery,the correct classification rate was improved by 3.5 and4.3 percentage points by combining phase synchronization with band energy.These indicate that the proposed method is effective and it is expected that the study provides a way to improve the performance of the online real-time brain-computer interaction control system based on EEG related to motor imagery. 展开更多
关键词 Brain-computer interaction(BCI) electroencephalogram(EEG) frequency band energy motor imagery phase synchronization
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Numerical modeling dynamic process of multi-feed microwave heating of industrial solution media 被引量:5
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作者 杨彪 孙俊 +7 位作者 李玮 彭金辉 李幼灵 罗会龙 郭胜惠 张竹敏 苏鹤州 史亚鸣 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第12期3192-3203,共12页
The exothermic efficiency of microwave heating an electrolyte/water solution is remarkably high due to the dielectric heating by orientation polarization of water and resistance heating by the Joule process occurred s... The exothermic efficiency of microwave heating an electrolyte/water solution is remarkably high due to the dielectric heating by orientation polarization of water and resistance heating by the Joule process occurred simultaneously compared with pure water.A three-dimensional finite element numerical model of multi-feed microwave heating industrial liquids continuously flowing in a meter-scale circular tube is presented.The temperature field inside the applicator tube in the cavity is solved by COMSOL Multiphysics and professional programming to describe the momentum,energy and Maxwell's equations.The evaluations of the electromagnetic field,the temperature distribution and the velocity field are simulated for the fluids dynamically heated by singleand multi-feed microwave system,respectively.Both the pilot experimental investigations and numerical results of microwave with single-feed heating for fluids with different effective permittivity and flow rates show that the presented numerical modeling makes it possible to analyze dynamic process of multi-feed microwave heating the industrial liquid.The study aids in enhancing the understanding and optimizing of dynamic process in the use of multi-feed microwave heating industrial continuous flow for a variety of material properties and technical parameters. 展开更多
关键词 microwave with multi-feed heating industrial flow dynamical process numerical computation solution media
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Design of good QC-LDPC codes without small girth in the p-plane 被引量:4
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作者 Lingjun Kong Yang Xiao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第2期183-187,共5页
A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check (QC-LDPC) codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filt... A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check (QC-LDPC) codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filtering the bad points, because the designed parity-check matrixes using these points have the short cycles in Tanner graph of codes. Then one of the best points from the residual good points of every line in the p-plane will be found, respectively. The optimal point is also singled out according to the bit error rate (BER) performance of the QC-LDPC codes at last. Explicit necessary and sufficient conditions for the QC-LDPC codes to have no short cycles are presented which are in favor of removing the bad points in the p-plane. Since preventing the short cycles also prevents the small stopping sets, the proposed construction method also leads to QC-LDPC codes with a higher stopping distance. 展开更多
关键词 quasi-cyclic low-density parity-check (QC-LDPC)codes circulant matrices GIRTH stopping set stopping distance.
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An E-Commerce Recommender System Based on Click and Purchase Data to Items and Considered of Interest Shifting of Customers 被引量:3
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作者 Duo Lin Wu Zhaoxia XU Shenggang 《China Communications》 SCIE CSCD 2015年第S2期72-82,共11页
A well-performed recommender system for an e-commerce web site can help customers easily find favorite items and then increase the turnover of merchants, hence it is important for both customers and merchants. In most... A well-performed recommender system for an e-commerce web site can help customers easily find favorite items and then increase the turnover of merchants, hence it is important for both customers and merchants. In most of the existing recommender systems, only the purchase information is utilized data and the navigational and behavioral data are seldom concerned. In this paper, we design a novel recommender system for comprehensive online shopping sites. In the proposed recommender system, the navigational and behavioral data, such as access, click, read, and purchase information of a customer, are utilized to calculate the preference degree to each item; then items with larger preference degrees are recommended to the customer. The proposed method has several innovations and two of them are more remarkable: one is that nonexpendable items are distinguished from expendable ones and handled by a different way; another is that the interest shifting of customers are considered. Lastly, we structure an example to show the operation procedure and the performance of the proposed recommender system. The results show that the proposed recommender method with considering interest shifting is superior to Kim et al(2011) method and the method without considering interest shifting. 展开更多
关键词 RECOMMENDER system online shopping E-COMMERCE preference degree
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Overview Landslide Hazard Assessment of China 被引量:3
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作者 YinKunlong ZhangGuirong ZhuLiangfeng 《Journal of China University of Geosciences》 SCIE CSCD 2004年第3期306-311,共6页
In recent years, China has suffered serious geological disasters, most of slope movements due to complex geology, geomorphology, unusual weather conditions, and large-scale land explorations during high speed economic... In recent years, China has suffered serious geological disasters, most of slope movements due to complex geology, geomorphology, unusual weather conditions, and large-scale land explorations during high speed economic development. According to geological hazard investigations organized by the Ministry of Land and Resources of China, there are 400 towns and more than 10 000 villages under the threatening of those landslide hazards. This paper presents the overview landslide hazard assessment in terms of GIS, which aims to evaluate the overview geohazard potentials, vulnerabilities of lives and land resources, and risks in conterminous China on the scale of 1∶6 000 000. This is the first overview landslide hazard potential map of China. 展开更多
关键词 LANDSLIDE geohazard potential ASSESSMENT China.
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Identification of emission sources of umbral flashes using phase congruency 被引量:2
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作者 Song Feng Lan Yu +1 位作者 Yun-Fei Yang Kai-Fan Ji 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第8期1001-1010,共10页
The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identific... The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency (PC), uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca n H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions. 展开更多
关键词 techniques image processing -- Sun chromosphere -- Sun photo- sphere -- sunspots -- convection
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Reliability Estimation for Component-Based Software Using General Masking Grouped Data 被引量:2
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作者 YANG Jian-feng CHEN Jing HU Wen-sheng 《Journal of Donghua University(English Edition)》 EI CAS 2016年第6期908-913,共6页
Masked data are the system failure data when exact component causing system failure might be unknown.In this paper,the mathematical description of general masked data was presented in software reliability engineering.... Masked data are the system failure data when exact component causing system failure might be unknown.In this paper,the mathematical description of general masked data was presented in software reliability engineering.Furthermore,a general maskedbased additive non-homogeneous Poisson process(NHPP) model was considered to analyze component reliability.However,the problem of masked-based additive model lies in the difficulty of estimating parameters.The maximum likelihood estimation procedure was derived to estimate parameters.Finally,a numerical example was given to illustrate the applicability of proposed model,and the immune particle swarm optimization(IPSO) algorithm was used in maximize log-likelihood function. 展开更多
关键词 masked data software reliability non-homogeneous Poisson process(NHPP) maximum likelihood estimation immune particle swarm optimization(IPSO)
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Simultaneous Detection of Flare-related Decaying and Decayless Kink Oscillations Using Jerk-aware Motion Magnification 被引量:1
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作者 Xiaowei Guo Bo Liang +2 位作者 Song Feng Wei Dai Yunfei Yang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第11期130-136,共7页
Kink oscillations of coronal loops are often influenced by external events and this results in various changes of the oscillations.Studying the changes can provide valuable information for understanding kink oscillati... Kink oscillations of coronal loops are often influenced by external events and this results in various changes of the oscillations.Studying the changes can provide valuable information for understanding kink oscillations.Our observation focuses on a flare region acquired by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory spacecraft on 2016 March 23.There are a bunch of arched loops and an open loop near the region.However,their oscillations show very low amplitudes.So we used the jerk-aware motion method to magnify the weak oscillations.We found that before the flare onset at 02:59 UT,there were some large loops above the arched loops being raised rapidly.The properties of the weak oscillations show clear changes.On the one hand,the oscillations in the arched loops were decayless initially,but both their amplitude and period increased after 02:30 UT and before the flare onset.Once enhanced,the oscillations decayed with time.On the other hand,the oscillations in the open loop were nearly constant before and after 02:30 UT,but their period increased.This means that the changes in periods and amplitudes of oscillations are likely associated with the loops raised before the flare. 展开更多
关键词 Sun:corona Sun:oscillations Sun:flares waves
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Model analysis of crust motion in the Chinese mainland by CMONOC 被引量:1
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作者 Ding Kaihua Li Zhicai +1 位作者 Zou Rong Wang Qi 《Geodesy and Geodynamics》 2014年第4期1-8,共8页
We report a new horizontal Global Positioning System velocity field in the Chinese mainland from the data analysis of about 2000 GPS sites observed in 2009, 2011 and 2013 through three campaigns of the CMONOC project.... We report a new horizontal Global Positioning System velocity field in the Chinese mainland from the data analysis of about 2000 GPS sites observed in 2009, 2011 and 2013 through three campaigns of the CMONOC project. Assuming the crustal block to characterize their kinematic behaviors, we estimate parameters of 22 crustal blocks to fit the GPS-derived velocity by using GIPSY software. We restrict us to compare two competing models in which the rigid blocks and the deforming blocks are involved. Our modeling suggests that the most crustal blocks characterized by coherent movement and internal strain may be better in describing the kinematics of crustal deformation in the Chinese mainland. 展开更多
关键词 Chinese mainland crustal deformation GPS (Global Positioning System) block model model identification
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Analytical model of tilted driver–pickup coils for eddy current nondestructive evaluation 被引量:1
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作者 Bing-Hua Cao Chao Li +2 位作者 Meng-Bao Fan Bo Ye Gui-Yun Tian 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期125-131,共7页
A driver-pickup probe possesses better sensitivity and flexibility due to individual optimization of a coil.It is fre-quently observed in an eddy current(EC)array probe.In this work,a tilted non-coaxial driver-pickup ... A driver-pickup probe possesses better sensitivity and flexibility due to individual optimization of a coil.It is fre-quently observed in an eddy current(EC)array probe.In this work,a tilted non-coaxial driver-pickup probe above a multilayered conducting plate is analytically modeled with spatial transformation for eddy current nondestructive evalua-tion.Basically,the core of the formulation is to obtain the projection of magnetic vector potential(MVP)from the driver coil onto the vector along the tilted pickup coil,which is divided into two key steps.The first step is to make a projection of MVP along the pickup coil onto a horizontal plane,and the second one is to build the relationship between the pr,ojected MVP and the MVP along the driver coil.Afterwards,an analytical model for the case of a layered plate is established with the reflection and transmission theory of electromagnetic fields.The calculated values from the resulting model indicate good agreement with those from the finite element model(FEM)and experiments,which validates the developed analytical model. 展开更多
关键词 nondestructive evaluation eddy currents tilted coils analytical model
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Diagnosis of Vocal Cord Paralysis in Anaesthesia 被引量:1
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作者 余炜 曾孝平 +2 位作者 HAMID GholamHosseini ANDREW Cameron MICHAEL Harrison J 《Journal of Donghua University(English Edition)》 EI CAS 2011年第1期5-9,共5页
Vocal cord paralysis can occur as a complication o surgery or anaesthesia,if permanent is a significant clinica problem.Early detection is important to optimize the chance o repair,and avoid complications associated w... Vocal cord paralysis can occur as a complication o surgery or anaesthesia,if permanent is a significant clinica problem.Early detection is important to optimize the chance o repair,and avoid complications associated with an impaired swallow.An algorithm to detect altered vocal cord function was presented based on wavelet packet analysis(WPA) and suppor vector machines(SVM),and compared with the Hoarseness Diagram method(HDm),which was reported as an objective voice quality evaluation approach and could be used for pathological voice discrimination.Experiments using voice signals recorded from subjects before and after the procedure show high classification accuracy with the new algorithm,whereas HDm fails in the detection of a hoarse voice.This finding would help to develop a screening tool to detect the vocal structure damage during surgery. 展开更多
关键词 vocal cord paralysis wavelet packet analysis(WPA) support vector machine(SVM) ANAESTHESIA
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Characterizing motion types of G-band bright points in the quiet Sun 被引量:2
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作者 Yun-Fei Yang Hui-Xue Qu +4 位作者 Kai-Fan Ji Song Feng Hui Deng Jia-Ben Lin Feng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第4期569-582,共14页
We study the motion of G-band bright points (GBPs) in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT) is ... We study the motion of G-band bright points (GBPs) in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT) is used, and GBPs are automat- ically tracked by segmenting 3D evolutional structures in a space-time cube. After putting the GBPs that do not move during their lifetimes aside, the non-stationary GBPs are categorized into three types based on an index of their motion type. Most GBPs that move in straight or nearly straight lines are categorized as a straight mo- tion type, a few moving in rotary paths into rotary motion, and the others fall into a motion type we called erratic. The mean horizontal velocities are 2.18±0.08 km s-1, 1.63±0.09km s^-1 and 1.33±0.07 km s^-1 for straight, erratic and rotary motion types, respectively. We find that a GBP drifts at a higher and constant velocity during its whole life if it moves in a straight line. However, it has a lower and variational velocity if it moves on a rotary path. The diffusive process is ballistic-, super- and sub-diffusion for straight, erratic and rotary motion types, respectively. The corresponding diffusion index (γ) and coefficients (K) are 2.13±0.09 and 850±37km^2 s^-1, 1.82±0.07 and 331 ±24 km^2 s^-1, and 0.73±0.19 and 13±9 km^2 s^-1. In terms of direction of motion, it is homogeneous and isotropic, and usually persists between neighboring frames, no matter what motion type a GBP is classified as. 展开更多
关键词 techniques: image processing -- Sun: photosphere -- methods: dataanalysis -- methods: statistical
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Evolution of isolated G-band bright points: size, intensity and velocity 被引量:1
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作者 Yun-Fei Yang Jia-Ben Lin +3 位作者 Song Feng Kai-Fan Ji Hui Deng Feng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第6期741-752,共12页
We study the evolution pattern of isolated G-band bright points (GBPs) in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT), we... We study the evolution pattern of isolated G-band bright points (GBPs) in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT), we detect GBPs in each image by the Laplacian and Morphological Dilation algorithm, and track their evolutions by a 26-adjacent method in a three-dimensional space-time cube. For quantifying the evolution, we propose a quantification method based on lifetime normalization which aligns the different lifetimes to common stages. The quantification results show that, on average, the diameter of isolated GBPs changes from 166 to 173 km, then down to 165 km; the maximum intensity contrast changes from 1.012 to 1.027, then down to 1.011; however, the velocity changes from 1.709 to 1.593 km s-1, then up to 1.703 km s-i. The results indicate that the evolution follows a pattern such that the GBP is small, faint and fast-moving at the birth stage, becomes big, bright and slow-moving at the middle stage, then gets small, faint and fast-moving at the decay stage until disappearance. Although the differences are very small, a two-sample t-test is used to demonstrate there are significant differences in means between the distri- butions of the different stages. Furthermore, we quantify the relationship between the lifetimes of GBPs and their properties. It is found that there are positive correlations between the lifetimes and their sizes and intensities with correlation coefficients of 0.83 and 0.65, respectively; however, there is a negative correlation between the life- times and velocities with a correlation coefficient of-0.49. In summary, the longer the GBP persists, the bigger, brighter and slower it will be. 展开更多
关键词 techniques: image processing -- Sun: photosphere -- methods: dataanalysis -- methods: statistical
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Investigation of intergranular bright points from the New Vacuum Solar Telescope 被引量:1
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作者 Kai-Fan Ji Jian-Ping Xiong +4 位作者 Yong-Yuan Xiang Song Feng Hui Deng Feng Wang Yun-Fei Yang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第5期69-80,共12页
Six high-resolution TiO-band image sequences from the New Vacuum Solar Telescope (NVST) are used to investigate the properties of intergranular bright points (igBPs). We detect the igBPs using a Laplacian and morp... Six high-resolution TiO-band image sequences from the New Vacuum Solar Telescope (NVST) are used to investigate the properties of intergranular bright points (igBPs). We detect the igBPs using a Laplacian and morphological dilation algorithm (LMD) and automatically track them using a three- dimensional segmentation algorithm, and then investigate the morphologic, photometric and dynamic prop- erties of igBPs in terms of equivalent diameter, intensity contrast, lifetime, horizontal velocity, diffusion index, motion range and motion type. The statistical results confirm previous studies based on G-band or TiO-band igBPs from other telescopes. These results illustrate that TiO data from the NVST are stable and reliable, and are suitable for studying igBPs. In addition, our method is feasible for detecting and track- ing igBPs with TiO data from the NVST. With the aid of vector magnetograms obtained from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, the properties of igBPs are found to be strongly influenced by their embedded magnetic environments. The areal coverage, size and intensity contrast values of igBPs are generally larger in regions with higher magnetic flux. However, the dynamics of igBPs, includ- ing the horizontal velocity, diffusion index, ratio of motion range and index of motion type are generally larger in the regions with lower magnetic flux. This suggests that the absence of strong magnetic fields in the medium makes it possible for the igBPs to look smaller and weaker, diffuse faster, and move faster and further along a straighter path. 展开更多
关键词 techniques: image processing -- Sun: photosphere -- methods: data analysis -- methods:statistical
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Long-term hemispheric variation of the flare index 被引量:1
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作者 Song Feng Lin-Hua Deng Shi-Chun Xu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第3期343-350,共8页
The long-term hemispheric variation of the flare index is investigated. It is found that, (1) the phase difference of the flare index between the northern and southern hemispheres is about 6-7 months, which is near ... The long-term hemispheric variation of the flare index is investigated. It is found that, (1) the phase difference of the flare index between the northern and southern hemispheres is about 6-7 months, which is near the time delay between flare activity and sunspot activity; (2) both the dominant and phase-leading hemisphere of the flare index is the northern hemisphere in the considered time interval, implying that the hemispheric asynchrony of solar activity has a close connection with the N-S asymmetry of solar activity. 展开更多
关键词 Sun: activity -- Sun: flares -- methods: data analysis
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