As image manipulation technology advances rapidly,the malicious use of image tampering has alarmingly escalated,posing a significant threat to social stability.In the realm of image tampering localization,accurately l...As image manipulation technology advances rapidly,the malicious use of image tampering has alarmingly escalated,posing a significant threat to social stability.In the realm of image tampering localization,accurately localizing limited samples,multiple types,and various sizes of regions remains a multitude of challenges.These issues impede the model’s universality and generalization capability and detrimentally affect its performance.To tackle these issues,we propose FL-MobileViT-an improved MobileViT model devised for image tampering localization.Our proposed model utilizes a dual-stream architecture that independently processes the RGB and noise domain,and captures richer traces of tampering through dual-stream integration.Meanwhile,the model incorporating the Focused Linear Attention mechanism within the lightweight network(MobileViT).This substitution significantly diminishes computational complexity and resolves homogeneity problems associated with traditional Transformer attention mechanisms,enhancing feature extraction diversity and improving the model’s localization performance.To comprehensively fuse the generated results from both feature extractors,we introduce the ASPP architecture for multi-scale feature fusion.This facilitates a more precise localization of tampered regions of various sizes.Furthermore,to bolster the model’s generalization ability,we adopt a contrastive learning method and devise a joint optimization training strategy that leverages fused features and captures the disparities in feature distribution in tampered images.This strategy enables the learning of contrastive loss at various stages of the feature extractor and employs it as an additional constraint condition in conjunction with cross-entropy loss.As a result,overfitting issues are effectively alleviated,and the differentiation between tampered and untampered regions is enhanced.Experimental evaluations on five benchmark datasets(IMD-20,CASIA,NIST-16,Columbia and Coverage)validate the effectiveness of our proposed model.The meticulously calibrated FL-MobileViT model consistently outperforms numerous existing general models regarding localization accuracy across diverse datasets,demonstrating superior adaptability.展开更多
The paper firstly gives a brief introduction of the credit focus as a result of the competition among the branch banks of the Commercial Bank. Then from the viewpoint of the performance of the branch bank, an analysis...The paper firstly gives a brief introduction of the credit focus as a result of the competition among the branch banks of the Commercial Bank. Then from the viewpoint of the performance of the branch bank, an analysis is made on the mechanism of the formation of the credit focus. Based on the analysis, the paper points out that the Commercial Bank branches, under competition of the deposit restrain, have brought about excessive credit, which exceeds the finance required by the normal business. And finally the paper forms the credit risk of the bank.展开更多
A numerical wave flume with fully nonlinear free surface boundary conditions is adopted to investigate the temporal characteristics of extreme waves in the presence of wind at various speeds. Incident wave trains are ...A numerical wave flume with fully nonlinear free surface boundary conditions is adopted to investigate the temporal characteristics of extreme waves in the presence of wind at various speeds. Incident wave trains are numerically generated by a piston-type wave maker, and the wind-excited pressure is introduced into dynamic boundary conditions using a pressure distribution over steep crests, as defined by Jeffreys' sheltering mechanism.A boundary value problem is solved by a higher-order boundary element method(HOBEM) and a mixed Eulerian-Lagrangian time marching scheme. The proposed model is validated through comparison with published experimental data from a focused wave group. The influence of wind on extreme wave properties,including maximum extreme wave crest, focal position shift, and spectrum evolution, is also studied. To consider the effects of the wind-driven currents on a wave evolution, the simulations assume a uniform current over varying water depth. The results show that wind causes weak increases in the extreme wave crest, and makes the nonlinear energy transfer non-reversible in the focusing and defocusing processes. The numerical results also provide a comparison to demonstrate the shifts at focal points, considering the combined effects of the winds and the wind-driven currents.展开更多
The Chinese Government and citizens face enormous challenges of disaster management as widespread devastation,economic damages,and loss of human lives caused by increasing natural disasters.Disaster management require...The Chinese Government and citizens face enormous challenges of disaster management as widespread devastation,economic damages,and loss of human lives caused by increasing natural disasters.Disaster management requires a complicated iterative process that includes disaster monitoring,early detection,forecasting,loss assessment,and efficient analysis of disaster reduction.Each task typically involves the use of technologists and multiple geospatial information resources,including sensors,data sources,models,geo-tools,software packages,and computing resources.However,most existing disaster management systems operate in a typical passive data-centric mode,where resources cannot be fully utilized.This impediment is partially being addressed by the increasingly complex application requirements and the growing availability of diverse resources.In this paper,we summarize and analyze the practical problems experienced by the National Disaster Reduction Application System of China.To address the issues of data-centric,centralized,isolated solutions,we propose a novel Focusing Service Mechanism,which is capable of scheduling and allocating for optimum utilization of multiple resources,to dynamically generate collaborative and on-demand disaster information services.We also demonstrate the design and implementation of the Integrated Disaster Information Service System(IDISS).Through the service strategies of Virtualizing,Wrapping,and Integrating,disasterrelated resources are constructed into services in the IDISS.These services are dynamically aggregated into focusing service chains,for diverse disaster management tasks.Actual applications illustrate that the proposed service system can significantly improve the capability of disaster management in China.展开更多
基金This study was funded by the Science and Technology Project in Xi’an(No.22GXFW0123)this work was supported by the Special Fund Construction Project of Key Disciplines in Ordinary Colleges and Universities in Shaanxi Province,the authors would like to thank the anonymous reviewers for their helpful comments and suggestions.
文摘As image manipulation technology advances rapidly,the malicious use of image tampering has alarmingly escalated,posing a significant threat to social stability.In the realm of image tampering localization,accurately localizing limited samples,multiple types,and various sizes of regions remains a multitude of challenges.These issues impede the model’s universality and generalization capability and detrimentally affect its performance.To tackle these issues,we propose FL-MobileViT-an improved MobileViT model devised for image tampering localization.Our proposed model utilizes a dual-stream architecture that independently processes the RGB and noise domain,and captures richer traces of tampering through dual-stream integration.Meanwhile,the model incorporating the Focused Linear Attention mechanism within the lightweight network(MobileViT).This substitution significantly diminishes computational complexity and resolves homogeneity problems associated with traditional Transformer attention mechanisms,enhancing feature extraction diversity and improving the model’s localization performance.To comprehensively fuse the generated results from both feature extractors,we introduce the ASPP architecture for multi-scale feature fusion.This facilitates a more precise localization of tampered regions of various sizes.Furthermore,to bolster the model’s generalization ability,we adopt a contrastive learning method and devise a joint optimization training strategy that leverages fused features and captures the disparities in feature distribution in tampered images.This strategy enables the learning of contrastive loss at various stages of the feature extractor and employs it as an additional constraint condition in conjunction with cross-entropy loss.As a result,overfitting issues are effectively alleviated,and the differentiation between tampered and untampered regions is enhanced.Experimental evaluations on five benchmark datasets(IMD-20,CASIA,NIST-16,Columbia and Coverage)validate the effectiveness of our proposed model.The meticulously calibrated FL-MobileViT model consistently outperforms numerous existing general models regarding localization accuracy across diverse datasets,demonstrating superior adaptability.
文摘The paper firstly gives a brief introduction of the credit focus as a result of the competition among the branch banks of the Commercial Bank. Then from the viewpoint of the performance of the branch bank, an analysis is made on the mechanism of the formation of the credit focus. Based on the analysis, the paper points out that the Commercial Bank branches, under competition of the deposit restrain, have brought about excessive credit, which exceeds the finance required by the normal business. And finally the paper forms the credit risk of the bank.
基金The National Natural Science Foundation of China under contract Nos 51679036,51490672 and 51709038the Fundamental Research Funds for the Central Universities under contract Nos DUT17GJ202 and DUT16RC(3)113the Open Foundation of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering under contract No.2016490111
文摘A numerical wave flume with fully nonlinear free surface boundary conditions is adopted to investigate the temporal characteristics of extreme waves in the presence of wind at various speeds. Incident wave trains are numerically generated by a piston-type wave maker, and the wind-excited pressure is introduced into dynamic boundary conditions using a pressure distribution over steep crests, as defined by Jeffreys' sheltering mechanism.A boundary value problem is solved by a higher-order boundary element method(HOBEM) and a mixed Eulerian-Lagrangian time marching scheme. The proposed model is validated through comparison with published experimental data from a focused wave group. The influence of wind on extreme wave properties,including maximum extreme wave crest, focal position shift, and spectrum evolution, is also studied. To consider the effects of the wind-driven currents on a wave evolution, the simulations assume a uniform current over varying water depth. The results show that wind causes weak increases in the extreme wave crest, and makes the nonlinear energy transfer non-reversible in the focusing and defocusing processes. The numerical results also provide a comparison to demonstrate the shifts at focal points, considering the combined effects of the winds and the wind-driven currents.
基金This study was supported by the National Science and Technology Support Program of China[863 Program,grant number 03-Y30B06-9001-13/15,grant number 2012AA121305]the National Natural Science Foundation[grant number 41171311,grant number 41101354,grant number 41201440].
文摘The Chinese Government and citizens face enormous challenges of disaster management as widespread devastation,economic damages,and loss of human lives caused by increasing natural disasters.Disaster management requires a complicated iterative process that includes disaster monitoring,early detection,forecasting,loss assessment,and efficient analysis of disaster reduction.Each task typically involves the use of technologists and multiple geospatial information resources,including sensors,data sources,models,geo-tools,software packages,and computing resources.However,most existing disaster management systems operate in a typical passive data-centric mode,where resources cannot be fully utilized.This impediment is partially being addressed by the increasingly complex application requirements and the growing availability of diverse resources.In this paper,we summarize and analyze the practical problems experienced by the National Disaster Reduction Application System of China.To address the issues of data-centric,centralized,isolated solutions,we propose a novel Focusing Service Mechanism,which is capable of scheduling and allocating for optimum utilization of multiple resources,to dynamically generate collaborative and on-demand disaster information services.We also demonstrate the design and implementation of the Integrated Disaster Information Service System(IDISS).Through the service strategies of Virtualizing,Wrapping,and Integrating,disasterrelated resources are constructed into services in the IDISS.These services are dynamically aggregated into focusing service chains,for diverse disaster management tasks.Actual applications illustrate that the proposed service system can significantly improve the capability of disaster management in China.