In recent years,there has been a backlash of sorts and the authenticity of images has been routinely questioned.Seeing is no longer believing.There is an urgent need for robust image forensic techniques to expose phot...In recent years,there has been a backlash of sorts and the authenticity of images has been routinely questioned.Seeing is no longer believing.There is an urgent need for robust image forensic techniques to expose photo forgery.This paper proposed a novel and effective technique to expose image forgery using inconsistent reflection.More specifically,a new technique was presented to calculate reflection line midpoint,the definition of midpoint ratio was given,and three standards were proposed and employed to detect image forgery.Accuracy and effectiveness of the proposed technique were evaluated using a data set consisting of 200 authentic and forged images.Experimental results indicate that the proposed method can detect image forgery with very high success rate.展开更多
As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the loca...As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the local time-frequency characteristics(LTFCH).Under the constraint of the uncertainty principle in the time-frequency domain(TFD),the LTFCH of those non-stationary signals can be determined by evolutionary spectrum analysis(ESA).In this paper,by analyzing the QRS complexes of both MCG and ECG data from healthy volunteers,we have derived some characteristic parameters(CHPs) in the TFD,such as the quality factor(Q) and center frequency(fz).According to the experiment results,we believe that there are threshold ranges of Q and fz values in the dynamic behavior of the cardiac system for healthy projects.If the CHPs are in the proper ranges,the cardiac system is in a normal condition and homeostasis can be self-correcting.In contrast,if the values of the CHPs are less than the proper ranges,the homeostasis of the cardiac system is lost and some cardiac diseases may result.The assumption of the threshold ranges is verified by sample data from different cardiac diseases,and the results support the assumption.The CHPs are not only a kind of new reference criterion for ECG in clinical diagnosis,but also afford a technological route for the application of MCGs in cardiology.展开更多
The Critical Cluster Model (CCM) is an optimization model assessing the evacuation risk on the scale of neighborhoods.The static evacuation risk in the CCM is measured by Bulk Lane Demand (BLD)-an index that solely de...The Critical Cluster Model (CCM) is an optimization model assessing the evacuation risk on the scale of neighborhoods.The static evacuation risk in the CCM is measured by Bulk Lane Demand (BLD)-an index that solely depends on network structure and population of evacuees.The advantage of the CCM is having less input parameters and with relatively smaller computational cost.Moreover,the process of risk assessment by the CCM is a global optimization process.For this reason,the CCM provides a relatively ideal solution for planning emergency traffic evacuation in open spaces.Considering that hazard installations in urban areas are becoming an increasing threat to urban safety,in the paper we proposed an evacuation risk assessment model with consideration of such installations.This model was developed on the basis of the CCM by introducing two important factors:the accident risk impact factor which was negatively correlated with distance,representing the impact of hazard installation;the evacuation direction which was under the consideration of evacuating away from the hazard installation,providing feasible evacuation routes.Finally,an application of the new model was presented for Beijing,China with the support of Geographical Information System (GIS).展开更多
基金Fundamental Research Funds for the Central Universities,China
文摘In recent years,there has been a backlash of sorts and the authenticity of images has been routinely questioned.Seeing is no longer believing.There is an urgent need for robust image forensic techniques to expose photo forgery.This paper proposed a novel and effective technique to expose image forgery using inconsistent reflection.More specifically,a new technique was presented to calculate reflection line midpoint,the definition of midpoint ratio was given,and three standards were proposed and employed to detect image forgery.Accuracy and effectiveness of the proposed technique were evaluated using a data set consisting of 200 authentic and forged images.Experimental results indicate that the proposed method can detect image forgery with very high success rate.
基金supported by the National Natural Science Foundation of China (607710003)
文摘As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the local time-frequency characteristics(LTFCH).Under the constraint of the uncertainty principle in the time-frequency domain(TFD),the LTFCH of those non-stationary signals can be determined by evolutionary spectrum analysis(ESA).In this paper,by analyzing the QRS complexes of both MCG and ECG data from healthy volunteers,we have derived some characteristic parameters(CHPs) in the TFD,such as the quality factor(Q) and center frequency(fz).According to the experiment results,we believe that there are threshold ranges of Q and fz values in the dynamic behavior of the cardiac system for healthy projects.If the CHPs are in the proper ranges,the cardiac system is in a normal condition and homeostasis can be self-correcting.In contrast,if the values of the CHPs are less than the proper ranges,the homeostasis of the cardiac system is lost and some cardiac diseases may result.The assumption of the threshold ranges is verified by sample data from different cardiac diseases,and the results support the assumption.The CHPs are not only a kind of new reference criterion for ECG in clinical diagnosis,but also afford a technological route for the application of MCGs in cardiology.
文摘The Critical Cluster Model (CCM) is an optimization model assessing the evacuation risk on the scale of neighborhoods.The static evacuation risk in the CCM is measured by Bulk Lane Demand (BLD)-an index that solely depends on network structure and population of evacuees.The advantage of the CCM is having less input parameters and with relatively smaller computational cost.Moreover,the process of risk assessment by the CCM is a global optimization process.For this reason,the CCM provides a relatively ideal solution for planning emergency traffic evacuation in open spaces.Considering that hazard installations in urban areas are becoming an increasing threat to urban safety,in the paper we proposed an evacuation risk assessment model with consideration of such installations.This model was developed on the basis of the CCM by introducing two important factors:the accident risk impact factor which was negatively correlated with distance,representing the impact of hazard installation;the evacuation direction which was under the consideration of evacuating away from the hazard installation,providing feasible evacuation routes.Finally,an application of the new model was presented for Beijing,China with the support of Geographical Information System (GIS).