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Malicious Document Detection Based on GGE Visualization
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作者 Youhe Wang Yi Sun +1 位作者 Yujie Li Chuanqi Zhou 《Computers, Materials & Continua》 SCIE EI 2025年第1期1233-1254,共22页
With the development of anti-virus technology,malicious documents have gradually become the main pathway of Advanced Persistent Threat(APT)attacks,therefore,the development of effective malicious document classifiers ... With the development of anti-virus technology,malicious documents have gradually become the main pathway of Advanced Persistent Threat(APT)attacks,therefore,the development of effective malicious document classifiers has become particularly urgent.Currently,detection methods based on document structure and behavioral features encounter challenges in feature engineering,these methods not only have limited accuracy,but also consume large resources,and usually can only detect documents in specific formats,which lacks versatility and adaptability.To address such problems,this paper proposes a novel malicious document detection method-visualizing documents as GGE images(Grayscale,Grayscale matrix,Entropy).The GGE method visualizes the original byte sequence of the malicious document as a grayscale image,the information entropy sequence of the document as an entropy image,and at the same time,the grayscale level co-occurrence matrix and the texture and spatial information stored in it are converted into grayscale matrix image,and fuses the three types of images to get the GGE color image.The Convolutional Block Attention Module-EfficientNet-B0(CBAM-EfficientNet-B0)model is then used for classification,combining transfer learning and applying the pre-trained model on the ImageNet dataset to the feature extraction process of GGE images.As shown in the experimental results,the GGE method has superior performance compared with other methods,which is suitable for detecting malicious documents in different formats,and achieves an accuracy of 99.44%and 97.39%on Portable Document Format(PDF)and office datasets,respectively,and consumes less time during the detection process,which can be effectively applied to the task of detecting malicious documents in real-time. 展开更多
关键词 Malicious document VISUaliZATION EfficientNet-B0 convolutional block attention module GGE image
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Imaging characteristics of hypervascular focal nodular hyperplasialike lesions in patients with chronic alcoholic liver disease
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作者 Atsushi Urase Masakatsu Tsurusaki +3 位作者 Ryohei Kozuki Atsushi Kono Keitaro Sofue Kazunari Ishii 《World Journal of Gastroenterology》 SCIE CAS 2025年第2期61-70,共10页
BACKGROUND Focal nodular hyperplasia(FNH)-like lesions are hyperplastic formations in patients with micronodular cirrhosis and a history of alcohol abuse.Although pathologically similar to hepatocellular carcinoma(HCC... BACKGROUND Focal nodular hyperplasia(FNH)-like lesions are hyperplastic formations in patients with micronodular cirrhosis and a history of alcohol abuse.Although pathologically similar to hepatocellular carcinoma(HCC)lesions,they are benign.As such,it is important to develop methods to distinguish between FNH-like lesions and HCC.AIM To evaluate diagnostically differential radiological findings between FNH-like lesions and HCC.METHODS We studied pathologically confirmed FNH-like lesions in 13 patients with alco-holic cirrhosis[10 men and 3 women;mean age:54.5±12.5(33-72)years]who were negative for hepatitis-B surface antigen and hepatitis-C virus antibody and underwent dynamic computed tomography(CT)and magnetic resonance imaging(MRI),including superparamagnetic iron oxide(SPIO)and/or gadoxetic acid-enhanced MRI.Seven patients also underwent angiography-assisted CT.RESULTS The evaluated lesion features included arterial enhancement pattern,washout appearance(low density compared with that of surrounding liver parenchyma),signal intensity on T1-weighted image(T1WI)and T2-weighted image(T2WI),central scar presence,chemical shift on in-and out-of-phase images,and uptake pattern on gadoxetic acid-enhanced MRI hepatobiliary phase and SPIO-enhanced MRI.Eleven patients had multiple small lesions(<1.5 cm).Radiological features of FNH-like lesions included hypervascularity despite small lesions,lack of“corona-like”enhancement in the late phase on CT during hepatic angiography(CTHA),high-intensity on T1WI,slightly high-or iso-intensity on T2WI,no signal decrease in out-of-phase images,and complete SPIO uptake or incomplete/partial uptake of gadoxetic acid.Pathologically,similar to HCC,FNH-like lesions showed many unpaired arteries and sinusoidal capillarization.CONCLUSION Overall,the present study showed that FNH-like lesions have unique radiological findings useful for differential diagnosis.Specifically,SPIO-and/or gadoxetic acid-enhanced MRI and CTHA features might facilitate differential diagnosis of FNH-like lesions and HCC. 展开更多
关键词 Focal nodular hyperplasia Alcoholic liver disease Hepatocellular carcinoma Magnetic resonance imaging LIVER
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Recognition and quality mapping of traditional herbal drugs:way forward towards artificial intelligence
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作者 Sanyam Sharma Subh Naman Ashish Baldi 《Traditional Medicine Research》 2025年第1期12-26,共15页
The use of traditional herbal drugs derived from natural sources is on the rise due to their minimal side effects and numerous health benefits.However,a major limitation is the lack of standardized knowledge for ident... The use of traditional herbal drugs derived from natural sources is on the rise due to their minimal side effects and numerous health benefits.However,a major limitation is the lack of standardized knowledge for identifying and mapping the quality of these herbal medicines.This article aims to provide practical insights into the application of artificial intelligence for quality-based commercialization of raw herbal drugs.It focuses on feature extraction methods,image processing techniques,and the preparation of herbal images for compatibility with machine learning models.The article discusses commonly used image processing tools such as normalization,slicing,cropping,and augmentation to prepare images for artificial intelligence-based models.It also provides an overview of global herbal image databases and the models employed for herbal plant/drug identification.Readers will gain a comprehensive understanding of the potential application of various machine learning models,including artificial neural networks and convolutional neural networks.The article delves into suitable validation parameters like true positive rates,accuracy,precision,and more for the development of artificial intelligence-based identification and authentication techniques for herbal drugs.This article offers valuable insights and a conclusive platform for the further exploration of artificial intelligence in the field of herbal drugs,paving the way for smarter identification and authentication methods. 展开更多
关键词 artificial intelligence AYURVEDA machine learning models herbal drugs image pre-processing medicinal plants
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EACNet:Ensemble adversarial co-training neural network for handling missing modalities in MRI images for brain tumor segmentation
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作者 RAMADHAN Amran Juma CHEN Jing PENG Junlan 《Journal of Measurement Science and Instrumentation》 2025年第1期11-25,共15页
Brain tumor segmentation is critical in clinical diagnosis and treatment planning.Existing methods for brain tumor segmentation with missing modalities often struggle when dealing with multiple missing modalities,a co... Brain tumor segmentation is critical in clinical diagnosis and treatment planning.Existing methods for brain tumor segmentation with missing modalities often struggle when dealing with multiple missing modalities,a common scenario in real-world clinical settings.These methods primarily focus on handling a single missing modality at a time,making them insufficiently robust for the additional complexity encountered with incomplete data containing various missing modality combinations.Additionally,most existing methods rely on single models,which may limit their performance and increase the risk of overfitting the training data.This work proposes a novel method called the ensemble adversarial co-training neural network(EACNet)for accurate brain tumor segmentation from multi-modal magnetic resonance imaging(MRI)scans with multiple missing modalities.The proposed method consists of three key modules:the ensemble of pre-trained models,which captures diverse feature representations from the MRI data by employing an ensemble of pre-trained models;adversarial learning,which leverages a competitive training approach involving two models;a generator model,which creates realistic missing data,while sub-networks acting as discriminators learn to distinguish real data from the generated“fake”data.Co-training framework utilizes the information extracted by the multimodal path(trained on complete scans)to guide the learning process in the path handling missing modalities.The model potentially compensates for missing information through co-training interactions by exploiting the relationships between available modalities and the tumor segmentation task.EACNet was evaluated on the BraTS2018 and BraTS2020 challenge datasets and achieved state-of-the-art and competitive performance respectively.Notably,the segmentation results for the whole tumor(WT)dice similarity coefficient(DSC)reached 89.27%,surpassing the performance of existing methods.The analysis suggests that the ensemble approach offers potential benefits,and the adversarial co-training contributes to the increased robustness and accuracy of EACNet for brain tumor segmentation of MRI scans with missing modalities.The experimental results show that EACNet has promising results for the task of brain tumor segmentation of MRI scans with missing modalities and is a better candidate for real-world clinical applications. 展开更多
关键词 deep learning magnetic resonance imaging(MRI) medical image analysis semantic segmentation segmentation accuracy image synthesis
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清肺排毒汤联合肺保护通气对急性肺损伤(ALI)的疗效观察
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作者 李国兵 蔡永非 +1 位作者 王维 蒙贵阳潘宏梅 《中文科技期刊数据库(文摘版)医药卫生》 2025年第2期102-105,共4页
探讨清肺排毒汤联合肺保护通气策略对非新冠病毒感染导致的急性肺损伤(ALI)患者的临床疗效。方法 采用随机、对照方法。将2022年06月~2024年06月入住重庆市大足区中医院60例符合非新冠病毒感染导致的急性肺损伤(ALI)患者纳入,分成实验... 探讨清肺排毒汤联合肺保护通气策略对非新冠病毒感染导致的急性肺损伤(ALI)患者的临床疗效。方法 采用随机、对照方法。将2022年06月~2024年06月入住重庆市大足区中医院60例符合非新冠病毒感染导致的急性肺损伤(ALI)患者纳入,分成实验组和对照组,每组30例,对照组给予肺保护通气策略治疗,实验组在对照组基础上加用清肺排毒汤。观察两组患者1天、2天、3天、4天、5天、6天、7天ICU中医证候积分、氧浓度、氧分压、氧合指数、肺泡动脉氧分压差、最佳PEEP变化、CT下浸润影、斑片阴影变化或改善情况,进行数据整理分析,进行疗效评价。结果 实验组的治疗总有效率明显超越对照组,且在治疗后的1天~7天的各个评估时间点,实验组患者的中医症状评分均较对照组低,实验组患者的氧浓度(FiO2)、氧分压(PaO2)、氧合指数(PaO2/FiO2)在治疗后的各时间点均高于对照组,而肺泡动脉氧分压差(A-aDO2)则低于对照组,差异有统计学意义(P<0.05)。此外,实验组患者的最佳PEEP值在治疗过程中也呈现出更低的趋势,表明实验组患者的肺功能恢复情况优于对照组。结论 清肺排毒汤联合肺保护通气策略治疗非新冠病毒感染导致的急性肺损伤(ALI)疗效显著,能够有效改善患者症状及临床肺损伤监测生化物理参数,值得临床推广。 展开更多
关键词 清肺排毒汤 肺保护通气 急性肺损伤(ali)
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Exploring the frontiers of plant health:Harnessing NIR fluorescence and surface-enhanced Raman scattering modalities for innovative detection
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作者 Shu Tian Wenxin Huang +5 位作者 Junrui Hu Huiling Wang Zhipeng Zhang Liying Xu Junrong Li Yao Sun 《Chinese Chemical Letters》 2025年第3期134-143,共10页
Plants play a crucial role in maintaining ecological balance and biodiversity.However,plant health is easily affected by environmental stresses.Hence,the rapid and precise monitoring of plant health is crucial for glo... Plants play a crucial role in maintaining ecological balance and biodiversity.However,plant health is easily affected by environmental stresses.Hence,the rapid and precise monitoring of plant health is crucial for global food security and ecological balance.Currently,traditional detection strategies for monitoring plant health mainly rely on expensive equipment and complex operational procedures,which limit their widespread application.Fortunately,near-infrared(NIR)fluorescence and surface-enhanced Raman scattering(SERS)techniques have been recently highlighted in plants.NIR fluorescence imaging holds the advantages of being non-invasive,high-resolution and real-time,which is suitable for rapid screening in large-scale scenarios.While SERS enables highly sensitive and specific detection of trace chemical substances within plant tissues.Therefore,the complementarity of NIR fluorescence and SERS modalities can provide more comprehensive and accurate information for plant disease diagnosis and growth status monitoring.This article summarizes these two modalities in plant applications,and discusses the advantages of multimodal NIR fluorescence/SERS for a better understanding of a plant’s response to stress,thereby improving the accuracy and sensitivity of detection. 展开更多
关键词 NIR fluorescence SERS Plant biomarker detection Plant imaging PHYTOHORMONE
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TAL: Two-stream Adaptive Learning for Generalizable Person Re-identification
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作者 Yichao Yan Junjie Li +1 位作者 Shengcai Liao Jie Qin 《Machine Intelligence Research》 2025年第2期337-351,共15页
Domain generalizable person re-identification(reid)is a challenging task in computer vision,which aims to apply a trained reid model to unseen domains.Prior works either combine the data in all the training domains to... Domain generalizable person re-identification(reid)is a challenging task in computer vision,which aims to apply a trained reid model to unseen domains.Prior works either combine the data in all the training domains to capture domain-invariant features,or adopt a mixture of experts to investigate domain-specific information.In this work,we argue that both domain-specific and domain-invariant features are crucial for improving the generalization ability of reid models.To this end,we design a novel framework,which we name two-stream adaptive learning(TAL),to simultaneously model these two kinds of information.Specifically,a domain-specific stream is proposed to capture the training domain statistics with batch normalization(BN)parameters,whereas an adaptive matching layer is designed to dynamically aggregate domain-level information.In the meantime,we design an adaptive BN layer in the domain-invariant stream to approximate the statistic of unseen domains,such that our model is capable of handling various novel scenes.These two streams work adaptively and collaboratively to learn generalizable reid features.As validated by extensive experiments,our framework can be applied to both single-source and multi-source domain generalization tasks,where the results show that our framework notably outperforms the state-of-the-art methods. 展开更多
关键词 Person re-identification domain generalization image retrieval representation learning computer vision.
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Robust Image Forgery Localization Using Hybrid CNN-Transformer Synergy Based Framework
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作者 Sachin Sharma Brajesh Kumar Singh Hitendra Garg 《Computers, Materials & Continua》 2025年第3期4691-4708,共18页
Image tampering detection and localization have emerged as a critical domain in combating the pervasive issue of image manipulation due to the advancement of the large-scale availability of sophisticated image editing... Image tampering detection and localization have emerged as a critical domain in combating the pervasive issue of image manipulation due to the advancement of the large-scale availability of sophisticated image editing tools.The manual forgery localization is often reliant on forensic expertise.In recent times,machine learning(ML)and deep learning(DL)have shown promising results in automating image forgery localization.However,the ML-based method relies on hand-crafted features.Conversely,the DL method automatically extracts shallow spatial features to enhance the accuracy.However,DL-based methods lack the global co-relation of the features due to this performance degradation noticed in several applications.In the proposed study,we designed FLTNet(forgery localization transformer network)with a CNN(convolution neural network)encoder and transformer-based attention.The encoder extracts local high-dimensional features,and the transformer provides the global co-relation of the features.In the decoder,we have exclusively utilized a CNN to upsample the features that generate tampered mask images.Moreover,we evaluated visual and quantitative performance on three standard datasets and comparison with six state-of-the-art methods.The IoU values of the proposed method on CASIA V1,CASIA V2,and CoMoFoD datasets are 0.77,0.82,and 0.84,respectively.In addition,the F1-scores of these three datasets are 0.80,0.84,and 0.86,respectively.Furthermore,the visual results of the proposed method are clean and contain rich information,which can be used for real-time forgery detection.The code used in the study can be accessed through URL:https://github.com/ajit2k5/Forgery-Localization(accessed on 21 January 2025). 展开更多
关键词 Image tampering convolution neural network(CNN) HYBRID TRANSFORMER LOCaliZATION
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Semi-supervised cardiac magnetic resonance image segmentation based on domain generalization
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作者 SHAO Hong HOU Jinyang CUI Wencheng 《High Technology Letters》 2025年第1期41-52,共12页
In the realm of medical image segmentation,particularly in cardiac magnetic resonance imaging(MRI),achieving robust performance with limited annotated data is a significant challenge.Performance often degrades when fa... In the realm of medical image segmentation,particularly in cardiac magnetic resonance imaging(MRI),achieving robust performance with limited annotated data is a significant challenge.Performance often degrades when faced with testing scenarios from unknown domains.To address this problem,this paper proposes a novel semi-supervised approach for cardiac magnetic resonance image segmentation,aiming to enhance predictive capabilities and domain generalization(DG).This paper establishes an MT-like model utilizing pseudo-labeling and consistency regularization from semi-supervised learning,and integrates uncertainty estimation to improve the accuracy of pseudo-labels.Additionally,to tackle the challenge of domain generalization,a data manipulation strategy is introduced,extracting spatial and content-related information from images across different domains,enriching the dataset with a multi-domain perspective.This papers method is meticulously evaluated on the publicly available cardiac magnetic resonance imaging dataset M&Ms,validating its effectiveness.Comparative analyses against various methods highlight the out-standing performance of this papers approach,demonstrating its capability to segment cardiac magnetic resonance images in previously unseen domains even with limited annotated data. 展开更多
关键词 SEMI-SUPERVISED domain generalization(DG) cardiac magnetic resonance image segmentation
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Neuropsychological Guided Blind Image Quality Assessment via Noisy Label Optimization
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作者 Zhu Jinchi Ma Xiaoyu +1 位作者 Liu Chang Yu Dingguo 《China Communications》 2025年第2期173-187,共15页
Recent deep neural network(DNN)based blind image quality assessment(BIQA)approaches take mean opinion score(MOS)as ground-truth labels,which would lead to cross-datasets biases and limited generalization ability of th... Recent deep neural network(DNN)based blind image quality assessment(BIQA)approaches take mean opinion score(MOS)as ground-truth labels,which would lead to cross-datasets biases and limited generalization ability of the DNN-based BIQA model.This work validates the natural instability of MOS through investigating the neuropsychological characteristics inside the human visual system during quality perception.By combining persistent homology analysis with electroencephalogram(EEG),the physiologically meaningful features of the brain responses to different distortion levels are extracted.The physiological features indicate that although volunteers view exactly the same image content,their EEG features are quite varied.Based on the physiological results,we advocate treating MOS as noisy labels and optimizing the DNN based BIQA model with earlystop strategies.Experimental results on both innerdataset and cross-dataset demonstrate the superiority of our optimization approach in terms of generalization ability. 展开更多
关键词 blind image quality assessment deep neural network ELECTROENCEPHALOGRAM persistent homology
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Experimental study of postcritical deformation stage realization in layered composites during tension using digital image correlation and acoustic emission
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作者 Valeriy Wildemann Elena Strungar +2 位作者 Dmitrii Lobanov Artur Mugatarov Ekaterina Chebotareva 《Acta Mechanica Sinica》 2025年第2期163-175,共13页
Creating conditions to implement equilibrium processes of damage accumulation under a predictable scenario enables control over the failure of structural elements in critical states.It improves safety and reduces the ... Creating conditions to implement equilibrium processes of damage accumulation under a predictable scenario enables control over the failure of structural elements in critical states.It improves safety and reduces the probability of catastrophic behavior in case of accidents.Equilibrium damage accumulation in some cases leads to a falling part(called a postcritical stage)on the material’s stress-strain curve.It must be taken into account to assess the strength and deformation limits of composite structures.Digital image correlation method,acoustic emission(AE)signals recording,and optical microscopy were used in this paper to study the deformation and failure processes of an orthogonal-layup composite during tension in various directions to orthotropy axes.An elastic-plastic deformation model was proposed for the composite in a plane stress condition.The evolution of strain fields and neck formation were analyzed.The staging of the postcritical deformation process was described.AE signals obtained during tests were studied;characteristic damage types of a material were defined.The rationality and necessity of polymer composites’postcritical deformation stage taken into account in refined strength analysis of structures were concluded. 展开更多
关键词 Experimental mechanics Digital image correlation method Acoustic emission Postcritical deformation Polymer composite
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Degree centrality values in the left calcarine as a potential imaging biomarker for anxious major depressive disorder
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作者 Yu-Jun Gao Li-Li Meng +12 位作者 Zhao-Yuan Lu Xiang-You Li Ru-Qin Luo Hang Lin Zhi-Ming Pan Bao-Hua Xu Qian-Kun Huang Zhi-Gang Xiao Ting-Ting Li E Yin Nian Wei Chen Liu Hong Lin 《World Journal of Psychiatry》 2025年第4期60-72,共13页
BACKGROUND Major depressive disorder(MDD)with comorbid anxiety is an intricate psychiatric condition,but limited research is available on the degree centrality(DC)between anxious MDD and nonanxious MDD patients.AIM To... BACKGROUND Major depressive disorder(MDD)with comorbid anxiety is an intricate psychiatric condition,but limited research is available on the degree centrality(DC)between anxious MDD and nonanxious MDD patients.AIM To examine changes in DC values and their use as neuroimaging biomarkers in anxious and non-anxious MDD patients.METHODS We examined 23 anxious MDD patients,30 nonanxious MDD patients,and 28 healthy controls(HCs)using the DC for data analysis.RESULTS Compared with HCs,the anxious MDD group reported markedly reduced DC values in the right fusiform gyrus(FFG)and inferior occipital gyrus,whereas elevated DC values in the left middle frontal gyrus and left inferior parietal angular gyrus.The nonanxious MDD group exhibited surged DC values in the bilateral cerebellum IX,right precuneus,and opercular part of the inferior frontal gyrus.Unlike the nonanxious MDD group,the anxious MDD group exhibited declined DC values in the right FFG and bilateral calcarine(CAL).Besides,declined DC values in the right FFG and bilateral CAL negatively correlated with anxiety scores in the MDD group.CONCLUSION This study shows that abnormal DC patterns in MDD,especially in the left CAL,can distinguish MDD from its anxiety subtype,indicating a potential neuroimaging biomarker. 展开更多
关键词 Major depressive disorder ANXIETY Degree centrality Resting-state functional magnetic resonance imaging
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Optimality conditions for a class of variational inequalities with cone constraints
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作者 Wen DONG Junrong ZHANG +1 位作者 Yiyun WANG La HUANG 《Frontiers of Mathematics in China》 2025年第1期39-53,共15页
In this paper,through the use of image space analysis,optimality conditions for a class of variational inequalities with cone constraints are proposed.By virtue of the nonlinear scalarization function,known as the Ger... In this paper,through the use of image space analysis,optimality conditions for a class of variational inequalities with cone constraints are proposed.By virtue of the nonlinear scalarization function,known as the Gerstewitz function,three nonlinear weak separation functions,two nonlinear regular weak separation functions and a nonlinear strong separation function are introduced.According to nonlinearseparation functions,some optimality conditions of the weak and strong alternative for variational inequalities with cone constraints are derived. 展开更多
关键词 Variational inequalities with constraints image space analysis nonlinear separation function optimality condition
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An Attention-Based CNN Framework for Alzheimer’s Disease Staging with Multi-Technique XAI Visualization
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作者 Mustafa Lateef Fadhil Jumaili Emrullah Sonuç 《Computers, Materials & Continua》 2025年第5期2947-2969,共23页
Alzheimer’s disease(AD)is a significant challenge in modern healthcare,with early detection and accurate staging remaining critical priorities for effective intervention.While Deep Learning(DL)approaches have shown p... Alzheimer’s disease(AD)is a significant challenge in modern healthcare,with early detection and accurate staging remaining critical priorities for effective intervention.While Deep Learning(DL)approaches have shown promise in AD diagnosis,existing methods often struggle with the issues of precision,interpretability,and class imbalance.This study presents a novel framework that integrates DL with several eXplainable Artificial Intelligence(XAI)techniques,in particular attention mechanisms,Gradient-Weighted Class Activation Mapping(Grad-CAM),and Local Interpretable Model-Agnostic Explanations(LIME),to improve bothmodel interpretability and feature selection.The study evaluates four different DL architectures(ResMLP,VGG16,Xception,and Convolutional Neural Network(CNN)with attention mechanism)on a balanced dataset of 3714 MRI brain scans from patients aged 70 and older.The proposed CNN with attention model achieved superior performance,demonstrating 99.18%accuracy on the primary dataset and 96.64% accuracy on the ADNI dataset,significantly advancing the state-of-the-art in AD classification.The ability of the framework to provide comprehensive,interpretable results through multiple visualization techniques while maintaining high classification accuracy represents a significant advancement in the computational diagnosis of AD,potentially enabling more accurate and earlier intervention in clinical settings. 展开更多
关键词 Alzheimer’s disease deep learning early disease detection XAI medical image classification
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Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery 被引量:13
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作者 徐涵秋 《Journal of China University of Geosciences》 SCIE CSCD 2006年第2期146-150,157,共6页
In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illuminati... In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illumination Correction Model proposed by Markham and Irish and the Illumination and Atmospheric Correction Model developed by the Remote Sensing and GIS Laboratory of the Utah State University. Relative noise, correlation coefficient and slope value were used as the criteria for the evaluation and comparison, which were derived from pseudo-invarlant features identified from multitemporal Landsat image pairs of Xiamen (厦门) and Fuzhou (福州) areas, both located in the eastern Fujian (福建) Province of China. Compared with the unnormalized image, the radiometric differences between the normalized multitemporal images were significantly reduced when the seasons of multitemporal images were different. However, there was no significant difference between the normalized and unnorrealized images with a similar seasonal condition. Furthermore, the correction results of two algorithms are similar when the images are relatively clear with a uniform atmospheric condition. Therefore, the radiometric normalization procedures should be carried out if the multitemporal images have a significant seasonal difference. 展开更多
关键词 LANDSAT radiometrie correction data normalization pseudo-invariant features image processing.
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Evaluation of Structural Patterns and Related Alteration and Mineralization Zones by Using ASAR-ASTER Imagery in Siyahrood Area (East Azarbaijan—NW Iran) 被引量:9
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作者 Shabnam Khosroshahizadeh Mohsen Pourkermani +2 位作者 Mahmood Almasiyan Mehran Arian Ahmad Khakzad 《Open Journal of Geology》 2015年第9期589-610,共22页
The NW part of Iran belongs to the Iranian plateau that is a tectonically active region within the Alpine-Himalayan orogenic belt. The intrusion of Oligocene parts in various faces caused the alteration and mineraliza... The NW part of Iran belongs to the Iranian plateau that is a tectonically active region within the Alpine-Himalayan orogenic belt. The intrusion of Oligocene parts in various faces caused the alteration and mineralization such as copper, molybdenum, gold and iron in the Siyahrood area. Granitoidic rocks with component of Granodiorite to alkali have been influenced by hydrothermal fluids. Alteration zones are important features for the exploration of deposits and the ASTER sensor is able to identify the type of alteration and its alteration zoning. This method can be a useful tool for detecting potential mineralization area in East Azarbaijan—Northwest of Iran. The purpose of this study is to evaluate ASTER data for mapping altered minerals in Siyahrood area in order to detect the potential mineralized areas. In this study, false color composite, and band ratio techniques were applied on ASTER data and argillic, phyllic, Iron oxide and propylitic alteration zones were separated. ASAR image processing has been used for lineaments and faults identified by the aid of directional filter. The structural study focused on fracture zones and their characteristics including strike, length, and relationship with alteration zones. The results of this study demonstrate the usefulness of remote sensing methods and ASTER multi-spectral data for alteration, and ASAR data are useful for lineament mapping. 展开更多
关键词 Siyahrood Area ASTER Image LINEAMENTS Directional Filter Iran
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Lineament Patterns and Mineralization Related to Alteration Zone by Using ASAR-ASTER Imagery in Hize Jan-Sharaf Abad Au-Ag Epithermal Mineralized Zone (East Azarbaijan—NW Iran) 被引量:5
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作者 Shabnam Khosroshahizadeh Mohsen Pourkermani +2 位作者 Mahmood Almasian Mehran Arian Ahmad Khakzad 《Open Journal of Geology》 2016年第4期232-250,共19页
East Azarbaijan belongs to the Iranian plateau and is part of lesser Caucasus province. Studied area is located in west-central Alborz. The intrusion of oligocene bodies in various units causes the alteratio... East Azarbaijan belongs to the Iranian plateau and is part of lesser Caucasus province. Studied area is located in west-central Alborz. The intrusion of oligocene bodies in various units causes the alteration and mineralization in northwest of Iran. The Hizejan-Sharafabad is one of this named mineralized zone. Granitoidicrocks with component of Granodiorite to alkali have been influenced by hydrothermal fluids. Fractures and faults are as weak zone in earth surface and hydrothermal fluids rise to surface by these geological structures. These solutions cause to alteration in host rocks. Alteration zones are important features for the exploration of deposits. The altered rocks have specific absorption in some spectral portion and ASTER sensor is able to identify the type of alteration. Remote sensing method is useful tool for discovering altered area. The purpose of this study is to appraise ASTER data for surveying altered minerals in Hizejan-Sharafabad area in the event of detecting the potential mineralized areas. In this research, False Color Composite (FCC), Band ratio, and color composite ratio techniques are applied on ASTER data and Silica, Argilic, and Propylitic alteration zones are detected. These alteration types and mineralized area are related to Hizejan–Sharafabad fault which is absent in the fault maps. ASAR image processing has been used for lineaments and faults identified by the aid of Directional and Canny Algorithm filters. The structural study focuses on fracture zones and their characteristics including strike, length, and relationship with alteration zones. 展开更多
关键词 Hizejan-Sharafabad Lineament ASTER Image ASAR image NW Iran Directional and Canny Algorithm
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Calibration and Validation of an All-Sky Imager 被引量:3
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作者 HUO Juan LU Da-Ren 《Atmospheric and Oceanic Science Letters》 2009年第4期220-223,共4页
The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bratio... The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bration experiments of the all-sky imager,geometric an-gular calibration,optical calibration,and radiometric calibration,and then infers an algorithm to retrieve rela-tive radiance from the all-sky images.Field experiments show that the related coefficient between retrieved radi-ance and measured radiance is about 0.91.It is feasible to use the algorithm to retrieve radiance from images.The paper sets up a relationship between radiance and the im-age,which is useful for using the all-sky image in nu-merical-simulations that predict more meteorological pa-rameters. 展开更多
关键词 ALL-SKY VISIBLE image RADIANCE CLOUD
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Construction and Validation of a Geometry-based Mathematical Model for the Hard X-Ray Imager 被引量:1
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作者 Xian-Kai Jiang Jian Wu +4 位作者 Deng-Yi Chen Yi-Ming Hu Hao-Xiang Wang Wei Liu Zhe Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第2期53-72,共20页
Quantitative and analytical analysis of the modulation process of the collimator is a great challenge,and is also of great value to the design and development of Fourier transform imaging telescopes.The Hard X-ray Ima... Quantitative and analytical analysis of the modulation process of the collimator is a great challenge,and is also of great value to the design and development of Fourier transform imaging telescopes.The Hard X-ray Imager(HXI),as one of the three payloads onboard the Advanced Space-based Solar Observatory(ASO-S) mission,adopts modulating Fourier-Transformation imaging technique and will be used to explore the mechanism of energy release and transmission in solar flare activities.As an important step to reconstruct the images of solar flares,accurate modulation functions of HXI are needed.In this paper,a mathematical model is developed to analyze the modulation function under a simplified condition first.Then its behavior under six degrees of freedom is calculated after adding the rotation matrix and translation change to the model.In addition,unparalleled light and extended sources are also considered so that our model can be used to analyze the X-ray beam experiment.Next,applied to the practical HXI conditions,the model has been confirmed not only by Geant4 simulations but also by some verification experiments.Furthermore,how this model helps to improve the image reconstruction process after the launch of ASO-S is also presented. 展开更多
关键词 INSTRUMENTATION detectors-Sun X-rays-gamma-rays-techniques image processing-methods ANALYTICAL
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Calibration and Characterization of Hyperspectral Imaging Systems Used for Natural Scene Imagery 被引量:1
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作者 Nsikak E. Ekpenyong 《Optics and Photonics Journal》 2019年第7期81-98,共18页
Calibration and characterization of focal plane hyperspectral imaging systems play an important role in natural scene imagery. Illumination plays a major role during imaging, as both the camera and electronically tuna... Calibration and characterization of focal plane hyperspectral imaging systems play an important role in natural scene imagery. Illumination plays a major role during imaging, as both the camera and electronically tunable filter may suffer low transmission at the ends of the visible spectrum, resulting in a low signal to noise ratio. It is important that the spectral characteristics of the imaging system as well as its geometric properties be well characterized and its radiometric performance known. The aim of this article is to identify the main sources of errors in a common design of focal-plane hyperspectral imaging system and devise ways of compensating for these errors. Calibration and characterization of a focal-plane hyperspectral imaging system include nominal wavelength accuracy analysis. This was carried out by capturing images of a mercury vapour lamp to study principal emission lines in the visible spectrum. The linearity of the hyperspectral imaging system was investigated by recording an input-output function. This was accomplished by comparing signals captured by the hyperspectral imaging system and luminance data recorded using a luminance meter. System noise characterization was done by repeated acquisitions of dark noise images captured under identical conditions. Main meridian analysis was accomplished by obtaining sample edge patches from the centre and near-boundary of hyperspectral image and then constructing edge and line spread functions. The final test image analysis involved verifying system calibration, image correction and compensation algorithms. Results show that with proper calibration and characterization of imaging systems, high quality images are obtained and can be used for research works which include hyperspectral image registration and hyperspectral image recognition for natural scenes. 展开更多
关键词 HYPERSPECTRAL IMAGING CaliBRATION
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