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Algebraic processing technique for extracting frequency-dependent shear-wave splitting parameters in an anisotropic medium 被引量:1
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作者 韩开锋 曾新吾 《Applied Geophysics》 SCIE CSCD 2011年第2期134-140,177,共8页
Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth(1993),a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component V... Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth(1993),a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component VSP data in frequency-dependent medium has been developed.By using this dual source cumulative rotation technique in the frequency-domain(DCTF),anisotropic parameters,including polarization direction of the shear-waves and timedelay between the fast and slow shear-waves,can be estimated for each frequency component in the frequency domain.It avoids the possible error which comes from using a narrow-band filter in the current commonly used method.By using synthetic seismograms,the feasibility and validity of the technique was tested and a comparison with the currently used method was also given.The results demonstrate that the shear-wave splitting parameters frequency dependence can be extracted directly from four-component seismic data using the DCTF.In the presence of larger scale fractures,substantial frequency dependence would be found in the seismic frequency range,which implies that dispersion would occur at seismic frequencies.Our study shows that shear-wave anisotropy decreases as frequency increases. 展开更多
关键词 Algebraic processing technique ANISOTROPY shear-wave splitting frequency dependence
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Processing Technique of Instant Flavored Daylily(Hemerocallis citrina Baroni)
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作者 童斌 杨薇红 +4 位作者 贾君 洪文龙 韩艳丽 李志强 王毓宁 《Agricultural Science & Technology》 CAS 2016年第3期751-755,共5页
This study was conducted to investigate the recipe and process of instant pickle by multiple steps with dry daylily as a raw material, and an orthogonal test was adopted to obtain the optimal recipe and process. The p... This study was conducted to investigate the recipe and process of instant pickle by multiple steps with dry daylily as a raw material, and an orthogonal test was adopted to obtain the optimal recipe and process. The pickling process of the instant flavored daylily was conducted at an optimal crisp-keeping Ca Cl2 concentration at 0.050%, cooking time of 5 min, pickling time of 6 h and a salt concentration of 4%. The effects of various factors on product taste were in order of salt concentrationcooking timepickling timeCa Cl2 concentration.The obtained product has the characteristics of strong fragrance, crisp delicious taste and unique flavor with stomachic effect. 展开更多
关键词 DAYLILY INSTANT FLAVOR processing technique
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The State-of-the-Art Review on Applications of Intrusive Sensing,Image Processing Techniques,and Machine Learning Methods in Pavement Monitoring and Analysis 被引量:15
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作者 Yue Hou Qiuhan Li +5 位作者 Chen Zhang Guoyang Lu Zhoujing Ye Yihan Chen Linbing Wang Dandan Cao 《Engineering》 SCIE EI 2021年第6期845-856,共12页
In modern transportation,pavement is one of the most important civil infrastructures for the movement of vehicles and pedestrians.Pavement service quality and service life are of great importance for civil engineers a... In modern transportation,pavement is one of the most important civil infrastructures for the movement of vehicles and pedestrians.Pavement service quality and service life are of great importance for civil engineers as they directly affect the regular service for the users.Therefore,monitoring the health status of pavement before irreversible damage occurs is essential for timely maintenance,which in turn ensures public transportation safety.Many pavement damages can be detected and analyzed by monitoring the structure dynamic responses and evaluating road surface conditions.Advanced technologies can be employed for the collection and analysis of such data,including various intrusive sensing techniques,image processing techniques,and machine learning methods.This review summarizes the state-ofthe-art of these three technologies in pavement engineering in recent years and suggests possible developments for future pavement monitoring and analysis based on these approaches. 展开更多
关键词 Pavement monitoring and analysis The state-of-the-art review Intrusive sensing Image processing techniques Machine learning methods
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CONTROL TECHNIQUES FOR DIGESTION IN BAYER PROCESS 被引量:4
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作者 G.Y.Gan L.Z.Wang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第6期1174-1178,共5页
The control techniques for indirect heating digestion in Bayer process of alumina production were researched and developed. They include controlling chemical composition of slurry to be digested and controlling diges... The control techniques for indirect heating digestion in Bayer process of alumina production were researched and developed. They include controlling chemical composition of slurry to be digested and controlling digestion status and energy consumption. Very good performances and technical and technical and economical figures for digestion process have been obtained by carefully applying these comprehensive control techniques in Pingguo alumina refinery. 展开更多
关键词 control technique DIGESTION Bayer process
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Data driven particle size estimation of hematite grinding process using stochastic configuration network with robust technique 被引量:6
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作者 DAI Wei LI De-peng +1 位作者 CHEN Qi-xin CHAI Tian-you 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第1期43-62,共20页
As a production quality index of hematite grinding process,particle size(PS)is hard to be measured in real time.To achieve the PS estimation,this paper proposes a novel data driven model of PS using stochastic configu... As a production quality index of hematite grinding process,particle size(PS)is hard to be measured in real time.To achieve the PS estimation,this paper proposes a novel data driven model of PS using stochastic configuration network(SCN)with robust technique,namely,robust SCN(RSCN).Firstly,this paper proves the universal approximation property of RSCN with weighted least squares technique.Secondly,three robust algorithms are presented by employing M-estimation with Huber loss function,M-estimation with interquartile range(IQR)and nonparametric kernel density estimation(NKDE)function respectively to set the penalty weight.Comparison experiments are first carried out based on the UCI standard data sets to verify the effectiveness of these methods,and then the data-driven PS model based on the robust algorithms are established and verified.Experimental results show that the RSCN has an excellent performance for the PS estimation. 展开更多
关键词 hematite grinding process particle size stochastic configuration network robust technique M-estimation nonparametric kernel density estimation
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Improving the Segmentation of Arabic Handwriting Using Ligature Detection Technique
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作者 Husam Ahmad Al Hamad Mohammad Shehab 《Computers, Materials & Continua》 SCIE EI 2024年第5期2015-2034,共20页
Recognizing handwritten characters remains a critical and formidable challenge within the realm of computervision. Although considerable strides have been made in enhancing English handwritten character recognitionthr... Recognizing handwritten characters remains a critical and formidable challenge within the realm of computervision. Although considerable strides have been made in enhancing English handwritten character recognitionthrough various techniques, deciphering Arabic handwritten characters is particularly intricate. This complexityarises from the diverse array of writing styles among individuals, coupled with the various shapes that a singlecharacter can take when positioned differently within document images, rendering the task more perplexing. Inthis study, a novel segmentation method for Arabic handwritten scripts is suggested. This work aims to locatethe local minima of the vertical and diagonal word image densities to precisely identify the segmentation pointsbetween the cursive letters. The proposed method starts with pre-processing the word image without affectingits main features, then calculates the directions pixel density of the word image by scanning it vertically and fromangles 30° to 90° to count the pixel density fromall directions and address the problem of overlapping letters, whichis a commonly attitude in writing Arabic texts by many people. Local minima and thresholds are also determinedto identify the ideal segmentation area. The proposed technique is tested on samples obtained fromtwo datasets: Aself-curated image dataset and the IFN/ENIT dataset. The results demonstrate that the proposed method achievesa significant improvement in the proportions of cursive segmentation of 92.96% on our dataset, as well as 89.37%on the IFN/ENIT dataset. 展开更多
关键词 Arabic handwritten SEGMENTATION image processing ligature detection technique intelligent recognition
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Processing Technique of Carbonizing by Stir-Frying for Baked Rheum tanguticum Maxim.ex Balf. Optimized by Orthogonal Design 被引量:1
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作者 Shihe LIN YANDong YI +2 位作者 Chuanqi HUANG Quanwei YANG Nancai YU 《Medicinal Plant》 CAS 2019年第5期50-52,共3页
[Objectives]To optimize the processing technology of baked Rheum tanguticum carbon.[Methods]Firstly,the baking temperature and baking time were investigated by single factor,and the content of 5-hydroxymethylfurfural(... [Objectives]To optimize the processing technology of baked Rheum tanguticum carbon.[Methods]Firstly,the baking temperature and baking time were investigated by single factor,and the content of 5-hydroxymethylfurfural(5-HMF)was determined by HPLC.The main influencing factors of baking effect were baking temperature,baking time and tablet specifications.The L 9(34)orthogonal design experiment was carried out to optimize the processing technique of R.tanguticum carbon.[Results]The optimum processing technique was as follows:small-sized tablets,controlled oven baking temperature at(210±2)℃,and baking time of 20 min.[Conclusions]The optimum processing technique of R.tanguticum carbon is reasonable and feasible.Thus,this experiment can provide a certain reference for processing method and quality control of R.tanguticum carbon. 展开更多
关键词 RHEUM tanguticum carbon Carbonizing by Stir-Frying BAKING method processING technique
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A Systematic Review of Computer Vision Techniques for Quality Control in End-of-Line Visual Inspection of Antenna Parts
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作者 Zia Ullah Lin Qi +2 位作者 E.J.Solteiro Pires Arsénio Reis Ricardo Rodrigues Nunes 《Computers, Materials & Continua》 SCIE EI 2024年第8期2387-2421,共35页
The rapid evolution of wireless communication technologies has underscored the critical role of antennas in ensuring seamless connectivity.Antenna defects,ranging from manufacturing imperfections to environmental wear... The rapid evolution of wireless communication technologies has underscored the critical role of antennas in ensuring seamless connectivity.Antenna defects,ranging from manufacturing imperfections to environmental wear,pose significant challenges to the reliability and performance of communication systems.This review paper navigates the landscape of antenna defect detection,emphasizing the need for a nuanced understanding of various defect types and the associated challenges in visual detection.This review paper serves as a valuable resource for researchers,engineers,and practitioners engaged in the design and maintenance of communication systems.The insights presented here pave the way for enhanced reliability in antenna systems through targeted defect detection measures.In this study,a comprehensive literature analysis on computer vision algorithms that are employed in end-of-line visual inspection of antenna parts is presented.The PRISMA principles will be followed throughout the review,and its goals are to provide a summary of recent research,identify relevant computer vision techniques,and evaluate how effective these techniques are in discovering defects during inspections.It contains articles from scholarly journals as well as papers presented at conferences up until June 2023.This research utilized search phrases that were relevant,and papers were chosen based on whether or not they met certain inclusion and exclusion criteria.In this study,several different computer vision approaches,such as feature extraction and defect classification,are broken down and analyzed.Additionally,their applicability and performance are discussed.The review highlights the significance of utilizing a wide variety of datasets and measurement criteria.The findings of this study add to the existing body of knowledge and point researchers in the direction of promising new areas of investigation,such as real-time inspection systems and multispectral imaging.This review,on its whole,offers a complete study of computer vision approaches for quality control in antenna parts.It does so by providing helpful insights and drawing attention to areas that require additional exploration. 展开更多
关键词 Computer vision end-of-line visual inspection of antenna parts machine learning algorithms image processing techniques deep learning models
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Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques 被引量:1
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作者 Debin Shan and Youngsuk Kim School of Mechanical Engineering, Kyungpook National University, Taegu 702-70 1, South Korea Hyunsoo Kim Graduate School of Mechanical Engineering, Kyungpook National University, Taegu 702-701, South Korea E-mail: shandb@public 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第3期329-332,共4页
Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic... Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes. 展开更多
关键词 Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming processes with New Contact and Remeshing techniques FEM Simulation
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Effect of Different Processing Techniques on the Content of Total Alkaloids in Toddalia asiatica Lam.
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作者 Long CHEN Miao ZHANG +2 位作者 Daogen LAO Jiaying TANG Qiuyan HUANG 《Agricultural Biotechnology》 CAS 2019年第4期165-168,共4页
[Objectives]Effects of different processing techniques on the total alkaloid content in Toddalia asiatica Lam.were investigated by ultraviolet spectrophotometry.[Methods]T.asiatica was processed by the water washing m... [Objectives]Effects of different processing techniques on the total alkaloid content in Toddalia asiatica Lam.were investigated by ultraviolet spectrophotometry.[Methods]T.asiatica was processed by the water washing method,water boiling method,water steaming method,wine steaming method and wine processing method,and the total alkaloid content was determined by ultraviolet spectrophotometry.[Results]Different processing methods can affect the total alkaloid content in the medicinal materials.Among them,the water steaming method and the wine processing method can increase the total alkaloid content of the medicinal materials,and the degree of improvement was higher in the water steaming method;and the water boiling method,water washing method and wine steaming method can reduce the total alkaloid content of the materials,and showed a reduction order of water boiling method>water washing method>wine steaming method.[Conclusions]The water steaming method and the wine processing method can increase the total alkaloid content in T.asiatica,and the water boiling method,water washing method and wine steaming method can reduce the total alkaloid content of the medicinal material. 展开更多
关键词 Toddalia asiatica Lam. processING technique TOTAL ALKALOIDS ULTRAVIOLET SPECTROPHOTOMETRY
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PROCESSINGTECHNIQUESANDCHARACTERIZATIONOFCERAMICFIBERREINFORCEDALUMINIUMCOMPOSITES
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作者 Won Jong Choi Lu Ho Choi Department of Materials Engineering,Hankuk Aviation UniversityKoyang,Kyunggi do,Korea 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第1期9-14,共6页
This paper relates to the fabrication of aluminium matrix composites with various amounts of Al 2O 3 fiber and SiC whiskers by rheocasting, powder metallurgy process and liquid metal infiltration process. To analy... This paper relates to the fabrication of aluminium matrix composites with various amounts of Al 2O 3 fiber and SiC whiskers by rheocasting, powder metallurgy process and liquid metal infiltration process. To analyze wetting characteristics, the cross sections of composites are examined by scanning electron microscopy(SEM). The bending tests and microhardness tests are performed to evaluate mechanical properties of composites. The results show that the composites produced by liquid metal infiltration give better properties than those produced by rheocasting or powder metallurgy process, primarily due to the decrease of porosity and reinforcement cluster. For liquid metal infiltration composites, a good adhesion between the fiber and matrix is found. Three points bending test results show that there is an increase in flexural modulus with reinforcement contents. In addition, a series of microhardness tests are conducted to determine the effect of heat treatment on the mechanical property of Al 2O 3/Al composites. 展开更多
关键词 composite materials metal matrix composites reinforced metal composite processing techniques
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Phosphatidylserine:An overview on functionality,processing techniques,patents,and prospects
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作者 Jingnan Chen Jun Li +4 位作者 Haoyu Xu Jiaxi Li Yonghong Yuan Xuebing Xu Yanlan Bi 《Grain & Oil Science and Technology》 CAS 2023年第4期206-218,共13页
Phosphatidylserine(PS)is the part of cell structure in the body and has many beneficial functions especially in brain-related aging diseases.Although daily foods can provide PS to human body,the amount is very limited... Phosphatidylserine(PS)is the part of cell structure in the body and has many beneficial functions especially in brain-related aging diseases.Although daily foods can provide PS to human body,the amount is very limited due to its poverty in most foods.To overcome the issue,numerous studies based on PS have been reported to develop PS-related supplements.In this review,PS was comprehensively and critically reviewed from the view of resources,functions,processing techniques,patents,and prospects.For resources,animal,plant,and microorganism origins were all covered with their differences in composition profiles.For functions,benefits regarding memory,cognitive enhancement,exercise performance,reducing Alzheimer’s disease,and attention-deficit hyperactivity disorder symptoms were covered as well as the functional differences among animal-,plant-,and microorganism-based PS-related supplements.For processing techniques,traditional extracting methods from animal,plant,and microorganism tissues were comparatively discussed with enzymatic synthesis based on different reaction systems.Finally,patents of PS-related supplements were evaluated as well as their applications.This review could provide scientific and valuable support for PS industry. 展开更多
关键词 PHOSPHATIDYLSERINE FUNCTIONALITY processing techniques Patents evaluation PROSPECTS
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FUNDAMENTAL COMMUNICATIONS THEORIES AND SIGNAL PROCESSING TECHNIQUES FOR AMORPHOUS CELLULAR SYSTEMS
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作者 Shi Jin Feifei Gao +2 位作者 Kai Luo Yongming Huang Wei Peng 《China Communications》 SCIE CSCD 2016年第12期I0002-I0003,共2页
The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as w... The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as well as the wireless multi-media services.It is predicted that the network throughput will increase 展开更多
关键词 IEEE FBMC FUNDAMENTAL COMMUNICATIONS THEORIES AND SIGNAL processING techniqueS FOR AMORPHOUS CELLULAR SYSTEMS MIMO FIR
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Effects of Different Curing Techniques on Material and Aroma of Flue-cured Tobacco 被引量:2
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作者 崔国民 汪伯军 +3 位作者 罗以贵 许安定 陈益银 杨超 《Agricultural Science & Technology》 CAS 2014年第1期166-169,F0003,共5页
[Objective] The aim was to compare the effects of three-phase technique, quality and aromatic-flavor improvement technique and Zimbabwe technique on to-bacco quality to select a suitable technique in tobacco productio... [Objective] The aim was to compare the effects of three-phase technique, quality and aromatic-flavor improvement technique and Zimbabwe technique on to-bacco quality to select a suitable technique in tobacco production. [Method] Tobacco leaves in down, middle and upper parts of a tobacco variety KRK26 were col ected to analyze raw tobacco quality characters. [Result] With quality and aromatic-flavor improvement technique, the proportions of high-quality and middle/high quality tobac-cos improved by 4.68% and 1.97% and average price enhanced by 1.15 yuan/kg, increasing by 10.33%, 9.07% and 3.12 yuan/kg, compared with three-phase tech-nique. It is proved that the technique would better improve tobacco fragrance and quality and coordinate tobacco fragrance, taste and throat-irritation. [Conclusion] Quality and aromatic-flavor improvement technique provides references for tobacco production. 展开更多
关键词 Raw tobacco processing technique Tobacco quality
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Welding technique studies on the “West-East” pipeline project 被引量:1
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作者 隋永莉 杜则裕 +1 位作者 黄福祥 祁励春 《China Welding》 EI CAS 2006年第2期73-76,共4页
This paper described the work of welding process design for the " West-East" pipeline project, which is high pressure, large diameter and heavy wall thickness. According to the different geographical situation, clim... This paper described the work of welding process design for the " West-East" pipeline project, which is high pressure, large diameter and heavy wall thickness. According to the different geographical situation, climate, culture and the flexibility of the welding methods, this work recommended the semi-automatic process at the east and middle sections and automatic process at the west section of the pipeline project. The manual process is recommended on the tie-in joints and repairs. The double joint pipe and the 3 joint pipe are recommended at the water net place and some in-ditch welding place to reduce the welding volume. Also the special redesigned bevels are recommended for the automatic process and the semiautomatic process. Through all destructive tests, the results shows the welds are meet the requirements of related standards, specifications and design documents. 展开更多
关键词 "West-East" welding technique process design mechanical properties of welded joint
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A Novel Auto-Annotation Technique for Aspect Level Sentiment Analysis 被引量:1
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作者 Muhammad Aasim Qureshi Muhammad Asif +4 位作者 Mohd Fadzil Hassan Ghulam Mustafa Muhammad Khurram Ehsan Aasim Ali Unaza Sajid 《Computers, Materials & Continua》 SCIE EI 2022年第3期4987-5004,共18页
In machine learning,sentiment analysis is a technique to find and analyze the sentiments hidden in the text.For sentiment analysis,annotated data is a basic requirement.Generally,this data is manually annotated.Manual... In machine learning,sentiment analysis is a technique to find and analyze the sentiments hidden in the text.For sentiment analysis,annotated data is a basic requirement.Generally,this data is manually annotated.Manual annotation is time consuming,costly and laborious process.To overcome these resource constraints this research has proposed a fully automated annotation technique for aspect level sentiment analysis.Dataset is created from the reviews of ten most popular songs on YouTube.Reviews of five aspects—voice,video,music,lyrics and song,are extracted.An N-Gram based technique is proposed.Complete dataset consists of 369436 reviews that took 173.53 s to annotate using the proposed technique while this dataset might have taken approximately 2.07 million seconds(575 h)if it was annotated manually.For the validation of the proposed technique,a sub-dataset—Voice,is annotated manually as well as with the proposed technique.Cohen’s Kappa statistics is used to evaluate the degree of agreement between the two annotations.The high Kappa value(i.e.,0.9571%)shows the high level of agreement between the two.This validates that the quality of annotation of the proposed technique is as good as manual annotation even with far less computational cost.This research also contributes in consolidating the guidelines for the manual annotation process. 展开更多
关键词 Machine learning natural language processing ANNOTATION semi-annotated technique reviews annotation text annotation corpus annotation
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A Triple-Channel Encrypted Hybrid Fusion Technique to Improve Security of Medical Images 被引量:1
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作者 Ahmed S.Salama Mohamed Amr Mokhtar +2 位作者 Mazhar B.Tayel Esraa Eldesouky Ahmed Ali 《Computers, Materials & Continua》 SCIE EI 2021年第7期431-446,共16页
Assuring medical images protection and robustness is a compulsory necessity nowadays.In this paper,a novel technique is proposed that fuses the wavelet-induced multi-resolution decomposition of the Discrete Wavelet Tr... Assuring medical images protection and robustness is a compulsory necessity nowadays.In this paper,a novel technique is proposed that fuses the wavelet-induced multi-resolution decomposition of the Discrete Wavelet Transform(DWT)with the energy compaction of the Discrete Wavelet Transform(DCT).The multi-level Encryption-based Hybrid Fusion Technique(EbhFT)aims to achieve great advances in terms of imperceptibility and security of medical images.A DWT disintegrated sub-band of a cover image is reformed simultaneously using the DCT transform.Afterwards,a 64-bit hex key is employed to encrypt the host image as well as participate in the second key creation process to encode the watermark.Lastly,a PN-sequence key is formed along with a supplementary key in the third layer of the EbHFT.Thus,the watermarked image is generated by enclosing both keys into DWT and DCT coefficients.The fusions ability of the proposed EbHFT technique makes the best use of the distinct privileges of using both DWT and DCT methods.In order to validate the proposed technique,a standard dataset of medical images is used.Simulation results show higher performance of the visual quality(i.e.,57.65)for the watermarked forms of all types of medical images.In addition,EbHFT robustness outperforms an existing scheme tested for the same dataset in terms of Normalized Correlation(NC).Finally,extra protection for digital images from against illegal replicating and unapproved tampering using the proposed technique. 展开更多
关键词 Medical image processing digital image watermarking discrete wavelet transforms discrete cosine transform encryption image fusion hybrid fusion technique
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DEVELOPMENT OF FAST TWO-DIMENSIONAL HIGH-RESOLUTION DIRECTION-FINDING TECHNIQUES
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作者 吴仁彪 《Journal of Electronics(China)》 1994年第1期11-21,共11页
A fast separable approach based on a cross array is presented, which has coarsegrained parallelism. Its computational load is far less than that of the two-dimensional (2-D) direct processing method and other existing... A fast separable approach based on a cross array is presented, which has coarsegrained parallelism. Its computational load is far less than that of the two-dimensional (2-D) direct processing method and other existing separable approaches. In order to compensate for the performance degradation due to separable processing, two postprocessing schemes are also proposed. Some computer simulation results are provided for illustration in the end. 展开更多
关键词 Array SIGNAL processING HIGH-RESOLUTION direction-finding techniqueS SEPARABLE processING
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Applied the Large Scale Particle Image Velocimetry Technique for Measurement the Velocity of Gravity Currents in the Laboratory
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作者 Dhafar Ibrahim Ahmed Noureddine Latrache Blaise Nsom 《Journal of Water Resource and Protection》 2015年第8期597-604,共8页
This study includes a series of laboratory experiments for investigated the gravity current of fresh water with density ρ-?ρ, and initial speed u0 upon the free surface of an ambient liquid (salty water) with densi... This study includes a series of laboratory experiments for investigated the gravity current of fresh water with density ρ-?ρ, and initial speed u0 upon the free surface of an ambient liquid (salty water) with density ρ at rest in a basin. It’s have been presented to illuminate the dominant flow and transport phenomena in the presence of river, stream and wetland ecology, stream corridor restoration, in the case of accidental pollution spills. The characterized of the local kinematic field, i.e. the local velocity and vorticity fields, the measurement methods include particle image velocimetry (PIV) at the water surface using a technique similar to large scale of particle image velocimetry (LSPIV). 展开更多
关键词 Gravity CURRENTS IMAGE processing Large-Scale Particle IMAGE VELOCIMETRY technique SPATIOTEMPORAL DIAGRAMS technique
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An improved astrometric calibration technique for space debris observation
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作者 Rong-Yu Sun Chang-Yin Zhao Yao Lu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第2期81-88,共8页
An optical survey is the main technique for detecting space debris. Due to the specific character- istics of observation, the pointing errors and tracking errors of the telescope as well as image degradation may be si... An optical survey is the main technique for detecting space debris. Due to the specific character- istics of observation, the pointing errors and tracking errors of the telescope as well as image degradation may be significant, which make it difficult for astrometric calibration. Here we present an improved method that corrects the pointing and tracking errors, and measures the image position precisely. The pipeline is tested on a number of CCD images obtained from a 1-m telescope administered by Xinjiang Astronomical Observatory while observing a GPS satellite. The results show that the position measurement error of the background stars is around 0.1 pixel, while the time cost for a single frame is about 7.5 s; hence the relia- bility and accuracy of our method are demonstrated. In addition, our method shows a versatile and feasible way to perform space debris observation utilizing non-dedicated telescopes, which means more sensors could be involved and the ability to perform surveys could be improved. 展开更多
关键词 techniqueS image processing -- space vehicles -- astrometry -- methods data analysis
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