期刊文献+
共找到22,474篇文章
< 1 2 250 >
每页显示 20 50 100
Importance-aware 3D volume visualization for medical content-based image retrieval-a preliminary study
1
作者 Mingjian LI Younhyun JUNG +1 位作者 Michael FULHAM Jinman KIM 《虚拟现实与智能硬件(中英文)》 EI 2024年第1期71-81,共11页
Background A medical content-based image retrieval(CBIR)system is designed to retrieve images from large imaging repositories that are visually similar to a user′s query image.CBIR is widely used in evidence-based di... Background A medical content-based image retrieval(CBIR)system is designed to retrieve images from large imaging repositories that are visually similar to a user′s query image.CBIR is widely used in evidence-based diagnosis,teaching,and research.Although the retrieval accuracy has largely improved,there has been limited development toward visualizing important image features that indicate the similarity of retrieved images.Despite the prevalence of 3D volumetric data in medical imaging such as computed tomography(CT),current CBIR systems still rely on 2D cross-sectional views for the visualization of retrieved images.Such 2D visualization requires users to browse through the image stacks to confirm the similarity of the retrieved images and often involves mental reconstruction of 3D information,including the size,shape,and spatial relations of multiple structures.This process is time-consuming and reliant on users'experience.Methods In this study,we proposed an importance-aware 3D volume visualization method.The rendering parameters were automatically optimized to maximize the visibility of important structures that were detected and prioritized in the retrieval process.We then integrated the proposed visualization into a CBIR system,thereby complementing the 2D cross-sectional views for relevance feedback and further analyses.Results Our preliminary results demonstrate that 3D visualization can provide additional information using multimodal positron emission tomography and computed tomography(PETCT)images of a non-small cell lung cancer dataset. 展开更多
关键词 Volume visualization DVR Medical CBIR retrievAL Medical images
下载PDF
Orbit Weighting Scheme in the Context of Vector Space Information Retrieval
2
作者 Ahmad Ababneh Yousef Sanjalawe +2 位作者 Salam Fraihat Salam Al-E’mari Hamzah Alqudah 《Computers, Materials & Continua》 SCIE EI 2024年第7期1347-1379,共33页
This study introduces the Orbit Weighting Scheme(OWS),a novel approach aimed at enhancing the precision and efficiency of Vector Space information retrieval(IR)models,which have traditionally relied on weighting schem... This study introduces the Orbit Weighting Scheme(OWS),a novel approach aimed at enhancing the precision and efficiency of Vector Space information retrieval(IR)models,which have traditionally relied on weighting schemes like tf-idf and BM25.These conventional methods often struggle with accurately capturing document relevance,leading to inefficiencies in both retrieval performance and index size management.OWS proposes a dynamic weighting mechanism that evaluates the significance of terms based on their orbital position within the vector space,emphasizing term relationships and distribution patterns overlooked by existing models.Our research focuses on evaluating OWS’s impact on model accuracy using Information Retrieval metrics like Recall,Precision,InterpolatedAverage Precision(IAP),andMeanAverage Precision(MAP).Additionally,we assessOWS’s effectiveness in reducing the inverted index size,crucial for model efficiency.We compare OWS-based retrieval models against others using different schemes,including tf-idf variations and BM25Delta.Results reveal OWS’s superiority,achieving a 54%Recall and 81%MAP,and a notable 38%reduction in the inverted index size.This highlights OWS’s potential in optimizing retrieval processes and underscores the need for further research in this underrepresented area to fully leverage OWS’s capabilities in information retrieval methodologies. 展开更多
关键词 Information retrieval orbit weighting scheme semantic text analysis Tf-Idf weighting scheme vector space model
下载PDF
Comparison between ozonesonde measurements and satellite retrievals over Beijing,China 被引量:1
3
作者 Jinqiang Zhang Yuejian Xuan +5 位作者 Jianchun Bian Holger Vomel Yunshu Zeng Zhixuan Bai Dan Li Hongbin Chen 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第1期14-20,共7页
从2013年开始,作者团队使用自主研发电化学原理臭氧探空仪在华北平原北京地区进行每周一次观测.本研究首次使用2013-2019年期间北京地区臭氧探空数据评估Aqua卫星搭载大气红外探测仪(AIRS)和Aura卫星搭载微波临边探测器(MLS)反演垂直臭... 从2013年开始,作者团队使用自主研发电化学原理臭氧探空仪在华北平原北京地区进行每周一次观测.本研究首次使用2013-2019年期间北京地区臭氧探空数据评估Aqua卫星搭载大气红外探测仪(AIRS)和Aura卫星搭载微波临边探测器(MLS)反演垂直臭氧廓线,并对比臭氧探空,AIRS和Aura卫星搭载臭氧监测仪(OMI)臭氧柱总量结果.尽管臭氧探空与卫星反演垂直臭氧廓线在局部高度处差异较大,但整体来说两者较为接近(相对偏差大多<10%).臭氧探空,AIRS和OMI三种仪器测量臭氧柱总量的年变化特征较为一致,其年均臭氧柱总量分别为351.8±18.4 DU,348.8±19.5 DU和336.9±14.2 DU.后续对国内多站点观测数据分析将有助于进一步理解臭氧探空与卫星反演臭氧资料在不同区域的一致性. 展开更多
关键词 臭氧探空 卫星反演 垂直臭氧廓线 臭氧柱总量 华北平原
下载PDF
A Visual Indoor Localization Method Based on Efficient Image Retrieval
4
作者 Mengyan Lyu Xinxin Guo +1 位作者 Kunpeng Zhang Liye Zhang 《Journal of Computer and Communications》 2024年第2期47-66,共20页
The task of indoor visual localization, utilizing camera visual information for user pose calculation, was a core component of Augmented Reality (AR) and Simultaneous Localization and Mapping (SLAM). Existing indoor l... The task of indoor visual localization, utilizing camera visual information for user pose calculation, was a core component of Augmented Reality (AR) and Simultaneous Localization and Mapping (SLAM). Existing indoor localization technologies generally used scene-specific 3D representations or were trained on specific datasets, making it challenging to balance accuracy and cost when applied to new scenes. Addressing this issue, this paper proposed a universal indoor visual localization method based on efficient image retrieval. Initially, a Multi-Layer Perceptron (MLP) was employed to aggregate features from intermediate layers of a convolutional neural network, obtaining a global representation of the image. This approach ensured accurate and rapid retrieval of reference images. Subsequently, a new mechanism using Random Sample Consensus (RANSAC) was designed to resolve relative pose ambiguity caused by the essential matrix decomposition based on the five-point method. Finally, the absolute pose of the queried user image was computed, thereby achieving indoor user pose estimation. The proposed indoor localization method was characterized by its simplicity, flexibility, and excellent cross-scene generalization. Experimental results demonstrated a positioning error of 0.09 m and 2.14° on the 7Scenes dataset, and 0.15 m and 6.37° on the 12Scenes dataset. These results convincingly illustrated the outstanding performance of the proposed indoor localization method. 展开更多
关键词 Visual Indoor Positioning Feature Point Matching Image retrieval Position Calculation Five-Point Method
下载PDF
First-in-man implantation of the retrievable and repositionable VenusA-Plus valve 被引量:4
5
作者 Xian-bao Liu Yu-xin He +10 位作者 Chun-hui Liu Li-han Wang Feng Gao Lei Yu Ai-qiang Dong Min-jian Kong Ji-fang Chen Yong Xu Qi-jing Zhou Min Yan Jian-an Wang 《World Journal of Emergency Medicine》 SCIE CAS 2018年第1期64-66,共3页
BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. ... BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. METHODS: A 76-year-old patient with symptomatic severe aortic stenosis and high surgical risk(STS 13.8%) was recommended for transcatheter aortic valve replacement(TAVR) by heart valve team. Type 0 bicuspid aortic valve with asymmetric calcification was identified by dual source computed tomography, and the unfavorable anatomies increased the possibility of malposition and paravalvular leakage during TAVR. Therefore, we used the retrievable and repositionable Venus APlus valve for the patient.RESULTS: Transfemoral TAVR was performed under local anesthesia with sedation, and a 26-mm VenusA-Plus valve was successfully implanted. No transvalvular pressure gradient and trace paravalvular leakage were found. CONCLUSION: The successful first-in-man implantation indicates the retrievable and repositionable Venus A-Plus valve is feasible in complicated TAVR cases such as bicuspid aortic valve. 展开更多
关键词 Transcatheter aortic valve replacement Venus A-Plus valve retrievable Repositionable Bicuspid aortic valve
下载PDF
A Retrievable Data Perturbation Method Used in Privacy-Preserving in Cloud Computing 被引量:3
6
作者 YANG Pan 《China Communications》 SCIE CSCD 2014年第8期73-84,共12页
With the increasing popularity of cloud computing,privacy has become one of the key problem in cloud security.When data is outsourced to the cloud,for data owners,they need to ensure the security of their privacy;for ... With the increasing popularity of cloud computing,privacy has become one of the key problem in cloud security.When data is outsourced to the cloud,for data owners,they need to ensure the security of their privacy;for cloud service providers,they need some information of the data to provide high QoS services;and for authorized users,they need to access to the true value of data.The existing privacy-preserving methods can't meet all the needs of the three parties at the same time.To address this issue,we propose a retrievable data perturbation method and use it in the privacy-preserving in data outsourcing in cloud computing.Our scheme comes in four steps.Firstly,an improved random generator is proposed to generate an accurate "noise".Next,a perturbation algorithm is introduced to add noise to the original data.By doing this,the privacy information is hidden,but the mean and covariance of data which the service providers may need remain unchanged.Then,a retrieval algorithm is proposed to get the original data back from the perturbed data.Finally,we combine the retrievable perturbation with the access control process to ensure only the authorized users can retrieve the original data.The experiments show that our scheme perturbs date correctly,efficiently,and securely. 展开更多
关键词 隐私保护 扰动方法 可回收 计算 隐私安全 原始数据 检索算法 服务供应商
下载PDF
Image Retrieval Based on Vision Transformer and Masked Learning 被引量:3
7
作者 李锋 潘煌圣 +1 位作者 盛守祥 王国栋 《Journal of Donghua University(English Edition)》 CAS 2023年第5期539-547,共9页
Deep convolutional neural networks(DCNNs)are widely used in content-based image retrieval(CBIR)because of the advantages in image feature extraction.However,the training of deep neural networks requires a large number... Deep convolutional neural networks(DCNNs)are widely used in content-based image retrieval(CBIR)because of the advantages in image feature extraction.However,the training of deep neural networks requires a large number of labeled data,which limits the application.Self-supervised learning is a more general approach in unlabeled scenarios.A method of fine-tuning feature extraction networks based on masked learning is proposed.Masked autoencoders(MAE)are used in the fine-tune vision transformer(ViT)model.In addition,the scheme of extracting image descriptors is discussed.The encoder of the MAE uses the ViT to extract global features and performs self-supervised fine-tuning by reconstructing masked area pixels.The method works well on category-level image retrieval datasets with marked improvements in instance-level datasets.For the instance-level datasets Oxford5k and Paris6k,the retrieval accuracy of the base model is improved by 7%and 17%compared to that of the original model,respectively. 展开更多
关键词 content-based image retrieval vision transformer masked autoencoder feature extraction
下载PDF
Toward Fine-grained Image Retrieval with Adaptive Deep Learning for Cultural Heritage Image 被引量:2
8
作者 Sathit Prasomphan 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1295-1307,共13页
Fine-grained image classification is a challenging research topic because of the high degree of similarity among categories and the high degree of dissimilarity for a specific category caused by different poses and scal... Fine-grained image classification is a challenging research topic because of the high degree of similarity among categories and the high degree of dissimilarity for a specific category caused by different poses and scales.A cul-tural heritage image is one of thefine-grained images because each image has the same similarity in most cases.Using the classification technique,distinguishing cultural heritage architecture may be difficult.This study proposes a cultural heri-tage content retrieval method using adaptive deep learning forfine-grained image retrieval.The key contribution of this research was the creation of a retrieval mod-el that could handle incremental streams of new categories while maintaining its past performance in old categories and not losing the old categorization of a cul-tural heritage image.The goal of the proposed method is to perform a retrieval task for classes.Incremental learning for new classes was conducted to reduce the re-training process.In this step,the original class is not necessary for re-train-ing which we call an adaptive deep learning technique.Cultural heritage in the case of Thai archaeological site architecture was retrieved through machine learn-ing and image processing.We analyze the experimental results of incremental learning forfine-grained images with images of Thai archaeological site architec-ture from world heritage provinces in Thailand,which have a similar architecture.Using afine-grained image retrieval technique for this group of cultural heritage images in a database can solve the problem of a high degree of similarity among categories and a high degree of dissimilarity for a specific category.The proposed method for retrieving the correct image from a database can deliver an average accuracy of 85 percent.Adaptive deep learning forfine-grained image retrieval was used to retrieve cultural heritage content,and it outperformed state-of-the-art methods infine-grained image retrieval. 展开更多
关键词 Fine-grained image adaptive deep learning cultural heritage image retrieval
下载PDF
Image Retrieval with Text Manipulation by Local Feature Modification 被引量:1
9
作者 查剑宏 燕彩蓉 +1 位作者 张艳婷 王俊 《Journal of Donghua University(English Edition)》 CAS 2023年第4期404-409,共6页
The demand for image retrieval with text manipulation exists in many fields, such as e-commerce and Internet search. Deep metric learning methods are used by most researchers to calculate the similarity between the qu... The demand for image retrieval with text manipulation exists in many fields, such as e-commerce and Internet search. Deep metric learning methods are used by most researchers to calculate the similarity between the query and the candidate image by fusing the global feature of the query image and the text feature. However, the text usually corresponds to the local feature of the query image rather than the global feature. Therefore, in this paper, we propose a framework of image retrieval with text manipulation by local feature modification(LFM-IR) which can focus on the related image regions and attributes and perform modification. A spatial attention module and a channel attention module are designed to realize the semantic mapping between image and text. We achieve excellent performance on three benchmark datasets, namely Color-Shape-Size(CSS), Massachusetts Institute of Technology(MIT) States and Fashion200K(+8.3%, +0.7% and +4.6% in R@1). 展开更多
关键词 image retrieval text manipulation ATTENTION local feature modification
下载PDF
Triplet Label Based Image Retrieval Using Deep Learning in Large Database 被引量:1
10
作者 K.Nithya V.Rajamani 《Computer Systems Science & Engineering》 SCIE EI 2023年第3期2655-2666,共12页
Recent days,Image retrieval has become a tedious process as the image database has grown very larger.The introduction of Machine Learning(ML)and Deep Learning(DL)made this process more comfortable.In these,the pair-wi... Recent days,Image retrieval has become a tedious process as the image database has grown very larger.The introduction of Machine Learning(ML)and Deep Learning(DL)made this process more comfortable.In these,the pair-wise label similarity is used tofind the matching images from the database.But this method lacks of limited propose code and weak execution of misclassified images.In order to get-rid of the above problem,a novel triplet based label that incorporates context-spatial similarity measure is proposed.A Point Attention Based Triplet Network(PABTN)is introduced to study propose code that gives maximum discriminative ability.To improve the performance of ranking,a corre-lating resolutions for the classification,triplet labels based onfindings,a spatial-attention mechanism and Region Of Interest(ROI)and small trial information loss containing a new triplet cross-entropy loss are used.From the experimental results,it is shown that the proposed technique exhibits better results in terms of mean Reciprocal Rank(mRR)and mean Average Precision(mAP)in the CIFAR-10 and NUS-WIPE datasets. 展开更多
关键词 Image retrieval deep learning point attention based triplet network correlating resolutions classification region of interest
下载PDF
Retrievable puncture anchor traction method for endoscopic ultrasound-guided gastroenterostomy: A porcine study
11
作者 Guo-Xin Wang Kai Zhang Si-Yu Sun 《World Journal of Gastroenterology》 SCIE CAS 2020年第25期3603-3610,共8页
BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)is an alternative method for the surgical treatment of gastric outlet obstruction,but it is regarded as a challenging technique for endoscopists as the ... BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)is an alternative method for the surgical treatment of gastric outlet obstruction,but it is regarded as a challenging technique for endoscopists as the bowel is highly mobile and can tent away.Thus,the technique requires superb skill.In order to improve EUS-GE,we have developed a retrievable puncture anchor traction(RPAT)device for EUSGE to address the issue of bowel tenting.AIM To evaluate the feasibility of RPAT-assisted EUS-GE using an animal model.METHODS Six Bama mini pigs each weighing between 15 and 20 kg underwent the RPATassisted EUS-GE procedure.Care was taken to ensure that the animals experienced minimal pain and discomfort.Two days prior to the procedure the animals were limited to a liquid diet.No oral intake was allowed on the day before the procedure.A fully covered metal stent was placed between the stomach and the intestine using the RPAT-assisted EUS-GE method.Infection in the animals was determined.Four weeks after the procedure,a standard gastroscope was inserted into the pig’s intestine through a previously created fistula in order to check the status of the stents under anesthesia.The pig was euthanized after examination.RESULTS The RPAT-assisted EUS-GE method allowed placement of the stents with no complications in all six animals.All the pigs tolerated a regular diet within hours of the procedure.The animals were monitored for four weeks after the RPATassisted EUS-GE,during which time all of the animals exhibited normal eating behavior and no signs of infection were observed.Endoscopic imaging performed four weeks after the RPAT-assisted EUS-GE showed that the stents remained patent and stable in all the animals.No tissue overgrowth or ingrowth was observed in any case.Each animal had a mature fistula,and the stents were removed without significant bleeding.Autopsies of all six pigs revealed complete adhesion between the intestine and the stomach wall.CONCLUSION The RPAT method helps reduce mobility of the bowel.Therefore,the RPATassisted EUS-GE method is a minimally invasive treatment modality. 展开更多
关键词 retrievable puncture anchor Endoscopic ultrasound Endoscopic ultrasoundguided gastroenterostomy Gastric outlet obstruction GASTROENTEROSTOMY Electrocauteryenhanced delivery of lumen-apposing metal stents
下载PDF
Learning Noise-Assisted Robust Image Features for Fine-Grained Image Retrieval
12
作者 Vidit Kumar Hemant Petwal +1 位作者 Ajay Krishan Gairola Pareshwar Prasad Barmola 《Computer Systems Science & Engineering》 SCIE EI 2023年第9期2711-2724,共14页
Fine-grained image search is one of the most challenging tasks in computer vision that aims to retrieve similar images at the fine-grained level for a given query image.The key objective is to learn discriminative fin... Fine-grained image search is one of the most challenging tasks in computer vision that aims to retrieve similar images at the fine-grained level for a given query image.The key objective is to learn discriminative fine-grained features by training deep models such that similar images are clustered,and dissimilar images are separated in the low embedding space.Previous works primarily focused on defining local structure loss functions like triplet loss,pairwise loss,etc.However,training via these approaches takes a long training time,and they have poor accuracy.Additionally,representations learned through it tend to tighten up in the embedded space and lose generalizability to unseen classes.This paper proposes a noise-assisted representation learning method for fine-grained image retrieval to mitigate these issues.In the proposed work,class manifold learning is performed in which positive pairs are created with noise insertion operation instead of tightening class clusters.And other instances are treated as negatives within the same cluster.Then a loss function is defined to penalize when the distance between instances of the same class becomes too small relative to the noise pair in that class in embedded space.The proposed approach is validated on CARS-196 and CUB-200 datasets and achieved better retrieval results(85.38%recall@1 for CARS-196%and 70.13%recall@1 for CUB-200)compared to other existing methods. 展开更多
关键词 Convolutional network zero-shot learning fine-grained image retrieval image representation image retrieval intra-class diversity feature learning
下载PDF
OSAP‐Loss:Efficient optimization of average precision via involving samples after positive ones towards remote sensing image retrieval
13
作者 Xin Yuan Xin Xu +4 位作者 Xiao Wang Kai Zhang Liang Liao Zheng Wang Chia‐Wen Lin 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第4期1191-1212,共22页
In existing remote sensing image retrieval(RSIR)datasets,the number of images among different classes varies dramatically,which leads to a severe class imbalance problem.Some studies propose to train the model with th... In existing remote sensing image retrieval(RSIR)datasets,the number of images among different classes varies dramatically,which leads to a severe class imbalance problem.Some studies propose to train the model with the ranking‐based metric(e.g.,average precision[AP]),because AP is robust to class imbalance.However,current AP‐based methods overlook an important issue:only optimising samples ranking before each positive sample,which is limited by the definition of AP and is prone to local optimum.To achieve global optimisation of AP,a novel method,namely Optimising Samples after positive ones&AP loss(OSAP‐Loss)is proposed in this study.Specifically,a novel superior ranking function is designed to make the AP loss differentiable while providing a tighter upper bound.Then,a novel loss called Optimising Samples after Positive ones(OSP)loss is proposed to involve all positive and negative samples ranking after each positive one and to provide a more flexible optimisation strategy for each sample.Finally,a graphics processing unit memory‐free mechanism is developed to thoroughly address the non‐decomposability of AP optimisation.Extensive experimental results on RSIR as well as conventional image retrieval datasets show the superiority and competitive performance of OSAP‐Loss compared to the state‐of‐the‐art. 展开更多
关键词 computer vision image retrieval metric learning
下载PDF
TECMH:Transformer-Based Cross-Modal Hashing For Fine-Grained Image-Text Retrieval
14
作者 Qiqi Li Longfei Ma +2 位作者 Zheng Jiang Mingyong Li Bo Jin 《Computers, Materials & Continua》 SCIE EI 2023年第5期3713-3728,共16页
In recent years,cross-modal hash retrieval has become a popular research field because of its advantages of high efficiency and low storage.Cross-modal retrieval technology can be applied to search engines,crossmodalm... In recent years,cross-modal hash retrieval has become a popular research field because of its advantages of high efficiency and low storage.Cross-modal retrieval technology can be applied to search engines,crossmodalmedical processing,etc.The existing main method is to use amulti-label matching paradigm to finish the retrieval tasks.However,such methods do not use fine-grained information in the multi-modal data,which may lead to suboptimal results.To avoid cross-modal matching turning into label matching,this paper proposes an end-to-end fine-grained cross-modal hash retrieval method,which can focus more on the fine-grained semantic information of multi-modal data.First,the method refines the image features and no longer uses multiple labels to represent text features but uses BERT for processing.Second,this method uses the inference capabilities of the transformer encoder to generate global fine-grained features.Finally,in order to better judge the effect of the fine-grained model,this paper uses the datasets in the image text matching field instead of the traditional label-matching datasets.This article experiment on Microsoft COCO(MS-COCO)and Flickr30K datasets and compare it with the previous classicalmethods.The experimental results show that this method can obtain more advanced results in the cross-modal hash retrieval field. 展开更多
关键词 Deep learning cross-modal retrieval hash learning TRANSFORMER
下载PDF
ViT2CMH:Vision Transformer Cross-Modal Hashing for Fine-Grained Vision-Text Retrieval
15
作者 Mingyong Li Qiqi Li +1 位作者 Zheng Jiang Yan Ma 《Computer Systems Science & Engineering》 SCIE EI 2023年第8期1401-1414,共14页
In recent years,the development of deep learning has further improved hash retrieval technology.Most of the existing hashing methods currently use Convolutional Neural Networks(CNNs)and Recurrent Neural Networks(RNNs)... In recent years,the development of deep learning has further improved hash retrieval technology.Most of the existing hashing methods currently use Convolutional Neural Networks(CNNs)and Recurrent Neural Networks(RNNs)to process image and text information,respectively.This makes images or texts subject to local constraints,and inherent label matching cannot capture finegrained information,often leading to suboptimal results.Driven by the development of the transformer model,we propose a framework called ViT2CMH mainly based on the Vision Transformer to handle deep Cross-modal Hashing tasks rather than CNNs or RNNs.Specifically,we use a BERT network to extract text features and use the vision transformer as the image network of the model.Finally,the features are transformed into hash codes for efficient and fast retrieval.We conduct extensive experiments on Microsoft COCO(MS-COCO)and Flickr30K,comparing with baselines of some hashing methods and image-text matching methods,showing that our method has better performance. 展开更多
关键词 Hash learning cross-modal retrieval fine-grained matching TRANSFORMER
下载PDF
Retrieval and Regional Distribution Analysis of Ammonia,Sulfur Dioxide and Nitrogen Dioxide in the Urban Environment Using Ultraviolet DOAS Algorithm
16
作者 Hao Chen Jie Xu +5 位作者 YiboHu Fuzhou Niu Zhiyan Li Dan Wang Guizhong Fu Chuanxin Li 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期1251-1262,共12页
Aiming at the in situ and mobile observation of urban environmental air pollution,a portable instrument using ultraviolet spectrum retrieval algorithm was developed based on the basis of Differential Optical Absorptio... Aiming at the in situ and mobile observation of urban environmental air pollution,a portable instrument using ultraviolet spectrum retrieval algorithm was developed based on the basis of Differential Optical Absorption Spectroscopy(DOAS)and multiple-pass cell technique.Typical trace gas pollutants,NH3,SO2,and NO2,were explored using their optical spectral characteristics in deep ultraviolet wavelength range from 210 to 215 nm.The gas concentration was retrieved by Lambert-Beer’s law and nonlinear least square method.With an optimized optical alignment,the detection limits of NH3,SO2,NO2 were estimated to be 2.2,2.3,and 36.2 ppb,respectively.The system was used in carrying out some cruise observations in Chengdu,China.During the entire period,the polluted gases showed varied distribution and typical daily average concentrations ofNH3,SO2,NO2 were 23.2,3.5,and 106.0 ppb,respectively.The contributions from different sources were analyzed combined with the HYSPLIT model.Results show that the portable DOAS system is a convenient and effective tool for regional distribution measurement and pollution source monitoring. 展开更多
关键词 Ultraviolet DOAS algorithm retrieve method white cell urban environment regional distribution
下载PDF
DCRL-KG: Distributed Multi-Modal Knowledge Graph Retrieval Platform Based on Collaborative Representation Learning
17
作者 Leilei Li Yansheng Fu +6 位作者 Dongjie Zhu Xiaofang Li Yundong Sun Jianrui Ding Mingrui Wu Ning Cao Russell Higgs 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期3295-3307,共13页
The knowledge graph with relational abundant information has been widely used as the basic data support for the retrieval platforms.Image and text descriptions added to the knowledge graph enrich the node information,... The knowledge graph with relational abundant information has been widely used as the basic data support for the retrieval platforms.Image and text descriptions added to the knowledge graph enrich the node information,which accounts for the advantage of the multi-modal knowledge graph.In the field of cross-modal retrieval platforms,multi-modal knowledge graphs can help to improve retrieval accuracy and efficiency because of the abundant relational infor-mation provided by knowledge graphs.The representation learning method is sig-nificant to the application of multi-modal knowledge graphs.This paper proposes a distributed collaborative vector retrieval platform(DCRL-KG)using the multi-modal knowledge graph VisualSem as the foundation to achieve efficient and high-precision multimodal data retrieval.Firstly,use distributed technology to classify and store the data in the knowledge graph to improve retrieval efficiency.Secondly,this paper uses BabelNet to expand the knowledge graph through multi-ple filtering processes and increase the diversification of information.Finally,this paper builds a variety of retrieval models to achieve the fusion of retrieval results through linear combination methods to achieve high-precision language retrieval and image retrieval.The paper uses sentence retrieval and image retrieval experi-ments to prove that the platform can optimize the storage structure of the multi-modal knowledge graph and have good performance in multi-modal space. 展开更多
关键词 Multi-modal retrieval distributed storage knowledge graph
下载PDF
Refined Sparse Representation Based Similar Category Image Retrieval
18
作者 Xin Wang Zhilin Zhu Zhen Hua 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期893-908,共16页
Given one specific image,it would be quite significant if humanity could simply retrieve all those pictures that fall into a similar category of images.However,traditional methods are inclined to achieve high-quality ... Given one specific image,it would be quite significant if humanity could simply retrieve all those pictures that fall into a similar category of images.However,traditional methods are inclined to achieve high-quality retrieval by utilizing adequate learning instances,ignoring the extraction of the image’s essential information which leads to difficulty in the retrieval of similar category images just using one reference image.Aiming to solve this problem above,we proposed in this paper one refined sparse representation based similar category image retrieval model.On the one hand,saliency detection and multi-level decomposition could contribute to taking salient and spatial information into consideration more fully in the future.On the other hand,the cross mutual sparse coding model aims to extract the image’s essential feature to the maximumextent possible.At last,we set up a database concluding a large number of multi-source images.Adequate groups of comparative experiments show that our method could contribute to retrieving similar category images effectively.Moreover,adequate groups of ablation experiments show that nearly all procedures play their roles,respectively. 展开更多
关键词 Similar category image retrieval saliency detection multi-level decomposition cross mutual sparse coding
下载PDF
Similarity matching method of power distribution system operating data based on neural information retrieval
19
作者 Kai Xiao Daoxing Li +2 位作者 Pengtian Guo Xiaohui Wang Yong Chen 《Global Energy Interconnection》 EI CAS CSCD 2023年第1期15-25,共11页
Operation control of power systems has become challenging with an increase in the scale and complexity of power distribution systems and extensive access to renewable energy.Therefore,improvement of the ability of dat... Operation control of power systems has become challenging with an increase in the scale and complexity of power distribution systems and extensive access to renewable energy.Therefore,improvement of the ability of data-driven operation management,intelligent analysis,and mining is urgently required.To investigate and explore similar regularities of the historical operating section of the power distribution system and assist the power grid in obtaining high-value historical operation,maintenance experience,and knowledge by rule and line,a neural information retrieval model with an attention mechanism is proposed based on graph data computing technology.Based on the processing flow of the operating data of the power distribution system,a technical framework of neural information retrieval is established.Combined with the natural graph characteristics of the power distribution system,a unified graph data structure and a data fusion method of data access,data complement,and multi-source data are constructed.Further,a graph node feature-embedding representation learning algorithm and a neural information retrieval algorithm model are constructed.The neural information retrieval algorithm model is trained and tested using the generated graph node feature representation vector set.The model is verified on the operating section of the power distribution system of a provincial grid area.The results show that the proposed method demonstrates high accuracy in the similarity matching of historical operation characteristics and effectively supports intelligent fault diagnosis and elimination in power distribution systems. 展开更多
关键词 Neural information retrieval Power distribution Graph data Operating section Similarity matching
下载PDF
Adequate alignment and interaction for cross-modal retrieval
20
作者 Mingkang WANG Min MENG +1 位作者 Jigang LIU Jigang WU 《Virtual Reality & Intelligent Hardware》 EI 2023年第6期509-522,共14页
Background Cross-modal retrieval has attracted widespread attention in many cross-media similarity search applications,particularly image-text retrieval in the fields of computer vision and natural language processing... Background Cross-modal retrieval has attracted widespread attention in many cross-media similarity search applications,particularly image-text retrieval in the fields of computer vision and natural language processing.Recently,visual and semantic embedding(VSE)learning has shown promising improvements in image text retrieval tasks.Most existing VSE models employ two unrelated encoders to extract features and then use complex methods to contextualize and aggregate these features into holistic embeddings.Despite recent advances,existing approaches still suffer from two limitations:(1)without considering intermediate interactions and adequate alignment between different modalities,these models cannot guarantee the discriminative ability of representations;and(2)existing feature aggregators are susceptible to certain noisy regions,which may lead to unreasonable pooling coefficients and affect the quality of the final aggregated features.Methods To address these challenges,we propose a novel cross-modal retrieval model containing a well-designed alignment module and a novel multimodal fusion encoder that aims to learn the adequate alignment and interaction of aggregated features to effectively bridge the modality gap.Results Experiments on the Microsoft COCO and Flickr30k datasets demonstrated the superiority of our model over state-of-the-art methods. 展开更多
关键词 Cross-modal retrieval Visual semantic embedding Feature aggregation Transformer
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部