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SAR Tomography with Improved Non-Local Means Filtering Based on Adaptive Window
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作者 Shenglei Wang Zhiyang Chen +1 位作者 Yuanhao Li Cheng Hu 《Journal of Beijing Institute of Technology》 EI CAS 2023年第6期670-684,共15页
In order to mitigate speckle noise in synthetic aperture radar(SAR)images and enhance the accuracy of SAR tomography,non-local means(NL-means)filtering has been proven to be an effective method for improving the quali... In order to mitigate speckle noise in synthetic aperture radar(SAR)images and enhance the accuracy of SAR tomography,non-local means(NL-means)filtering has been proven to be an effective method for improving the quality of SAR interferograms.Apart from considerations like noise type and the definition of similarity,the size and shape of filtering windows are critical factors influencing the efficacy of NL-means filtering,yet there has been limited research on this aspect.This paper introduces an enhanced NL-means filtering method based on adaptive windows,allowing for the automatic adjustment of filtering window size according to the amplitude information of the SAR interferogram.Simultaneously,a directional window is incorporated to align SAR interferograms,achieving the dual objective of preserving filtering standards and retaining detailed information.Experimental results on interferogram filtering and tomography,based on TerraSAR-X data,demonstrate that the proposed method effectively reduces phase noise while maintaining texture accuracy,thereby improving tomography quality. 展开更多
关键词 NL-means filter adaptive window SAR interferogram filtering SAR tomography
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Modified Laser Speckle Imaging with Adaptive Window
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作者 Ho-young JIN Hyun-chool SHIN +2 位作者 Kab-mun CHA Ki-won RHEE Nitish Thakor 《Journal of Measurement Science and Instrumentation》 CAS 2010年第3期238-241,共4页
One of the advantages of laser speckle is detecting microvascular through image processing. This paper proposes a new image processing method for laser speckle, adaptive window method that adaptively processes laser s... One of the advantages of laser speckle is detecting microvascular through image processing. This paper proposes a new image processing method for laser speckle, adaptive window method that adaptively processes laser speckle images in the space. Disadvantage of conventional fixed window method is that it uses the same window size regardless of target areas. Inherently laser speckle contains undesired noise. Thus a large window is helpful for removing the noise, but it results in low resolution of image. Otherwise a small window may detect micro vascular but it has limits in noise removal. To overcome this trade-off, the concept of adaptive window method is newly introduced to conventional laser speckle image analysis. In addition, the modified adaptive window method applied to other selection images. We have compared conventional Laser Speckle Contrast Analysis (LASCA) and its variants with the proposed method in terms of image quality and processing complexity, Moreover compared the result of the accompamed changing sdection images have also been compared. 展开更多
关键词 Laser Speckle Contrast Analysis (LASC) adaptive window laser speckle selection image
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Drift DetectionMethod Using DistanceMeasures and Windowing Schemes for Sentiment Classification
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作者 Idris Rabiu Naomie Salim +3 位作者 Maged Nasser Aminu Da’u Taiseer Abdalla Elfadil Eisa Mhassen Elnour Elneel Dalam 《Computers, Materials & Continua》 SCIE EI 2023年第3期6001-6017,共17页
Textual data streams have been extensively used in practical applications where consumers of online products have expressed their views regarding online products.Due to changes in data distribution,commonly referred t... Textual data streams have been extensively used in practical applications where consumers of online products have expressed their views regarding online products.Due to changes in data distribution,commonly referred to as concept drift,mining this data stream is a challenging problem for researchers.The majority of the existing drift detection techniques are based on classification errors,which have higher probabilities of false-positive or missed detections.To improve classification accuracy,there is a need to develop more intuitive detection techniques that can identify a great number of drifts in the data streams.This paper presents an adaptive unsupervised learning technique,an ensemble classifier based on drift detection for opinion mining and sentiment classification.To improve classification performance,this approach uses four different dissimilarity measures to determine the degree of concept drifts in the data stream.Whenever a drift is detected,the proposed method builds and adds a new classifier to the ensemble.To add a new classifier,the total number of classifiers in the ensemble is first checked if the limit is exceeded before the classifier with the least weight is removed from the ensemble.To this end,a weighting mechanism is used to calculate the weight of each classifier,which decides the contribution of each classifier in the final classification results.Several experiments were conducted on real-world datasets and the resultswere evaluated on the false positive rate,miss detection rate,and accuracy measures.The proposed method is also compared with the state-of-the-art methods,which include DDM,EDDM,and PageHinkley with support vector machine(SVM)and Naive Bayes classifiers that are frequently used in concept drift detection studies.In all cases,the results show the efficiency of our proposed method. 展开更多
关键词 Data streams sentiment analysis concept drift ensemble classification adaptive window
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A 12-bit 30-MS/s VCO-based SAR ADC with NOC-assisted multiple adaptive bypass windows 被引量:1
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作者 Xiangxin Pan Xiong Zhou +2 位作者 Sheng Chang Zhaoming Ding Qiang Li 《Journal of Semiconductors》 EI CAS CSCD 2020年第11期81-91,共11页
This paper proposes a technique that uses the number of oscillation cycles(NOC)of a VCO-based comparator to set multiple adaptive bypass windows in a 12-bit successive approximation register(SAR)analog-to-digital conv... This paper proposes a technique that uses the number of oscillation cycles(NOC)of a VCO-based comparator to set multiple adaptive bypass windows in a 12-bit successive approximation register(SAR)analog-to-digital converter(ADC).The analysis of the number of bit cycles,power and static performance shows that three adaptive bypass windows reduce power consumption,and decrease DNL and have similar INL,compared with the SAR ADC without bypass windows.In addition,a 1-bit split-and-recombination redundancy technique and a general bypass logic digital error correction method are proposed to address the settling issues and optimize the size of the bypass window.This design is implemented in 40 nm CMOS technology.The conversion frequency of the ADC reaches up to 30 MS/s.The ADC achieves an SFDR of 85.35 dB and 11.12-bit ENOB with Nyquist input,consuming 380μW,down from 427μW without multiple adaptive bypass windows,at a 1.1 V supply,resulting in a figure of merit(FoM)of 5.69 fJ/conversion-step. 展开更多
关键词 adaptive bypass window number of oscillation cycles(NOC) offset split-and-recombination redundancy SAR ADC VCO-based comparator
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Energy Efficient Window Control Scheme for IEEE 802.11ah (Wi-Fi HaLow) Based Networks
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作者 Yanru Wang Kok Keong Chai +1 位作者 Yue Chen John Schormans 《Journal of Electrical Engineering》 2017年第5期242-252,共11页
IEEE 802.11ah brings in Restricted Access Window (RAW) to decrease contention, which is the grouping-based MAC protocol. The way to group a large number of devices and application of RAW size would have influence on... IEEE 802.11ah brings in Restricted Access Window (RAW) to decrease contention, which is the grouping-based MAC protocol. The way to group a large number of devices and application of RAW size would have influence on the energy efficiency in the process of medium access and communications. In this paper, we study an efficient window control algorithm to improve the uplink energy efficiency with a novel retransmission scheme that utilises the next empty slot for retransmission in the uplink. The grouping scheme is based on the college admission game. The problem is formulated based on energy efficiency by probability theory and Marker chain. To optimise energy efficiency, a window control scheme is proposed to group the devices and set the adaptive window size (number of slots per RAW and internal slot interval) based on the number of groups, applications and the distance between devices and Access Point (AP). The optimal solution is derived by Gradient Descent approach. Simulation results show that our proposed algorithm outperforms existing one on uplink energy efficiency and fairness. 展开更多
关键词 IEEE 802.1 lah MAC RAW uplink energy efficiency GROUPING adaptive window.
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RFID unreliable data filtering by integrating adaptive sliding Window and Euclidean distance 被引量:4
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作者 Li-Lan Liu Zi-Long Yuan +2 位作者 Xue-Wei Liu Cheng Chen Ke-Sheng Wang 《Advances in Manufacturing》 SCIE CAS 2014年第2期121-129,共9页
Through improving the redundant data filtering of unreliable data filter for radio frequency identification(RFID) with sliding-window,a data filter which integrates self-adaptive sliding-window and Euclidean distanc... Through improving the redundant data filtering of unreliable data filter for radio frequency identification(RFID) with sliding-window,a data filter which integrates self-adaptive sliding-window and Euclidean distance is proposed.The input data required being filtered have been shunt by considering a large number of redundant data existing in the unreliable data for RFID and the redundant data in RFID are the main filtering object with utilizing the filter based on Euclidean distance.The comparison between the results from the method proposed in this paper and previous research shows that it can improve the accuracy of the RFID for unreliable data filtering and largely reduce the redundant reading rate. 展开更多
关键词 Radio frequency identification(RFID) adaptive sliding window Euclidean distance Redundant data
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Random Forests Algorithm Based Duplicate Detection in On-Site Programming Big Data Environment 被引量:1
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作者 Qianqian Li Meng Li +1 位作者 Lei Guo Zhen Zhang 《Journal of Information Hiding and Privacy Protection》 2020年第4期199-205,共7页
On-site programming big data refers to the massive data generated in the process of software development with the characteristics of real-time,complexity and high-difficulty for processing.Therefore,data cleaning is e... On-site programming big data refers to the massive data generated in the process of software development with the characteristics of real-time,complexity and high-difficulty for processing.Therefore,data cleaning is essential for on-site programming big data.Duplicate data detection is an important step in data cleaning,which can save storage resources and enhance data consistency.Due to the insufficiency in traditional Sorted Neighborhood Method(SNM)and the difficulty of high-dimensional data detection,an optimized algorithm based on random forests with the dynamic and adaptive window size is proposed.The efficiency of the algorithm can be elevated by improving the method of the key-selection,reducing dimension of data set and using an adaptive variable size sliding window.Experimental results show that the improved SNM algorithm exhibits better performance and achieve higher accuracy. 展开更多
关键词 On-site programming big data duplicate record detection random forests adaptive sliding window
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Adaptive fractional window increment of TCP in multihop ad hoc networks
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作者 Liang-hui DING Wen-jun ZHANG +2 位作者 Xin-bing WANG Liang QIAN You-yun XU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第6期820-827,共8页
We propose an adaptive fractional window increasing algorithm (AFW) to improve the performance of the fractional window increment (FeW) in (Nahm et al., 2005). AFW fully utilizes the bandwidth when the network is idle... We propose an adaptive fractional window increasing algorithm (AFW) to improve the performance of the fractional window increment (FeW) in (Nahm et al., 2005). AFW fully utilizes the bandwidth when the network is idle, and limits the op-erating window when the network is congested. We evaluate AFW and compare the total throughput of AFW with that of FeW in different scenarios over chain, grid, random topologies and with hybrid traffics. Extensive simulation through ns2 shows that AFW obtains 5% higher throughput than FeW, whose throughput is significantly higher than that of TCP-Newreno, with limited modi-fications. 展开更多
关键词 TCP MULTIHOP adaptive fractional window increasing algorithm (AFW)
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Speckle filtering of Synthetic Aperture Radar images using filters with object-size-adapted windows
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作者 Sahel Mahdavi Bahram Salehi +2 位作者 Cecilia Moloney Weimin Huang Brian Brisco 《International Journal of Digital Earth》 SCIE EI 2018年第7期703-729,共27页
Speckle degrades the radiometric quality of a Synthetic Aperture Radar(SAR)image.Previous methods for speckle reduction have used a fixedsize window for filtering the entire image.This,however,may not be effective fo... Speckle degrades the radiometric quality of a Synthetic Aperture Radar(SAR)image.Previous methods for speckle reduction have used a fixedsize window for filtering the entire image.This,however,may not be effective for the entire image,as land covers of different sizes require different filtering windows.In this paper,a novel method is proposed by which each pixel in the image is filtered with a window appropriate for the size of object within it.The real in-phase and the imaginary quadrature components of the SAR images determine the best window size and the pixels in the intensity image are filtered using their own optimal windows.The proposed method is presented for both singleand multi-polarized SAR images,and the results of several common filters that were modified are presented.This approach is applied to two RADARSAT-2 images:one over San Francisco,California,USA and the other over St.John’s,Newfoundland and Labrador,Canada,producing results that were similar to,or outperformed,comparable filters while retaining details and suppressing speckle effectively.While the method was successful for single-look intensity data,it offers great potential for multi-look and amplitude data as well. 展开更多
关键词 SPECKLE Synthetic Aperture Radar(SAR) FILTERS adaptive window size
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