This study looks into the current,and potential uses of Blockchain technology in business,specifically in Accounting and in cybersecurity.We relate Blockchain uses to current concerns within cybersecurity and accounti...This study looks into the current,and potential uses of Blockchain technology in business,specifically in Accounting and in cybersecurity.We relate Blockchain uses to current concerns within cybersecurity and accounting.We review the literature that includes topics such as Big Data in Accounting,blockchain’s use in financial security and cybersecurity,and its use in financial accounting though the use of ledger technology and also as a system of tracking financial misconduct.We also review the Department of Homeland Security plan for cybersecurity over the next few years to understand what the US Government plans because of the importance of cybersecurity development.We show that Blockchain impacts auditing in different ways that will change the profession drastically.We also find that blockchain should be effectively implemented into different aspects of cybersecurity,and accounting,such as Auditing and general accounting procedures.展开更多
To address the problem of the shortage of neutron detectors used in radiation portal monitors （RPMs）, caused by the 3He supply crisis, research on a cadmium-based capture-gated fast neutron detector is presented in ...To address the problem of the shortage of neutron detectors used in radiation portal monitors （RPMs）, caused by the 3He supply crisis, research on a cadmium-based capture-gated fast neutron detector is presented in this paper. The detector is composed of many 1 cm × 1 cm × 20 cm plastic scintillator cuboids covered by 0.1 mm thick film of cadmium. The detector uses cadmium to absorb thermal neutrons and produce capture 7-rays to indicate the detection of neutrons, and uses plastic scintillator to moderate neutrons and register y-rays. This design removes the volume competing relationship in traditional 3He counter-based fast neutron detectors, which hinders enhancement of the neutron detection efficiency. Detection efficiency of 21.66% ×1.22% has been achieved with a 40.4 cm× 40.4 cm × 20 cm overall detector volume. This detector can measure both neutrons and T-rays simultaneously. A small detector （20.2 cm × 20.2 cm × 20 cm） demonstrated a 3.3 % false alarm rate for a 252Cf source with a neutron yield of 1841 n/s from 50 cm away within 15 s measurement time. It also demonstrated a very low （〈0.06%） false alarm rate for a 3.21 × 10^5 Bq 137Cs source. This detector offers a potential single-detector replacement for both neutron and the y-ray detectors in RPM systems.展开更多
Purpose Coded-aperture gamma cameras play an important role for homeland security nowadays.They have limitedfield-of-view(FOV)which is a critical parameter for many applications.The FOV can be potentially increased by ...Purpose Coded-aperture gamma cameras play an important role for homeland security nowadays.They have limitedfield-of-view(FOV)which is a critical parameter for many applications.The FOV can be potentially increased by extending it to the penumbra area(partially coded FOV).Methods In this study,we analyzed this artifact phenomenon based on simulating a commercial coded-aperture gamma camera.The camera uses a modified uniformly redundant array(MURA)mask with a basic pattern of rank 11.Its opening angle of the basic pattern to the detector center is 26.36◦which is the commonly used non-artifact FOV(NAFOV).In some applications,the radiation source is a far-field single-point source.Thus,we extend its FOV to 40◦by including a part of the partially coded area,which is a trade-off between the FOV and image quality.Analytical calculations and simulation studies were carried out.The system matrix was calculated using the Sidden’s algorithm.The maximum likelihood expectation maximization(MLEM)reconstruction method was employed.Projections and reconstruction results of the point source at different positions were compared.The second moment of inertia was used as thefigure of merit.Results Results show that projections have periodic similarity with a period of NAFOV,and reconstructions also have periodic artifacts,i.e.,fromθtoθ+NAFOV.Artifacts are the most serious at the edge of the NAFOV.The upper and lower artifacts are more serious than the left and right artifacts due to the difference between the horizontal centerline(tungsten)and vertical centerline(holes expect the center unit)of the mask.Conclusions For a point source with high activity,artifacts can be reduced by increasing the iteration number of the MLEM reconstruction.Even at the edge of NAFOV,the point source can be possibly reconstructed thanks to the large size of the position sensitive detector(PSD)used.The noise will significantly increase artifacts,which may lead to error locate the point source with low activity at some specific positions.展开更多
文摘This study looks into the current,and potential uses of Blockchain technology in business,specifically in Accounting and in cybersecurity.We relate Blockchain uses to current concerns within cybersecurity and accounting.We review the literature that includes topics such as Big Data in Accounting,blockchain’s use in financial security and cybersecurity,and its use in financial accounting though the use of ledger technology and also as a system of tracking financial misconduct.We also review the Department of Homeland Security plan for cybersecurity over the next few years to understand what the US Government plans because of the importance of cybersecurity development.We show that Blockchain impacts auditing in different ways that will change the profession drastically.We also find that blockchain should be effectively implemented into different aspects of cybersecurity,and accounting,such as Auditing and general accounting procedures.
基金Supported by National Natural Science Foundation of China(11175098,11375095)
文摘To address the problem of the shortage of neutron detectors used in radiation portal monitors （RPMs）, caused by the 3He supply crisis, research on a cadmium-based capture-gated fast neutron detector is presented in this paper. The detector is composed of many 1 cm × 1 cm × 20 cm plastic scintillator cuboids covered by 0.1 mm thick film of cadmium. The detector uses cadmium to absorb thermal neutrons and produce capture 7-rays to indicate the detection of neutrons, and uses plastic scintillator to moderate neutrons and register y-rays. This design removes the volume competing relationship in traditional 3He counter-based fast neutron detectors, which hinders enhancement of the neutron detection efficiency. Detection efficiency of 21.66% ×1.22% has been achieved with a 40.4 cm× 40.4 cm × 20 cm overall detector volume. This detector can measure both neutrons and T-rays simultaneously. A small detector （20.2 cm × 20.2 cm × 20 cm） demonstrated a 3.3 % false alarm rate for a 252Cf source with a neutron yield of 1841 n/s from 50 cm away within 15 s measurement time. It also demonstrated a very low （〈0.06%） false alarm rate for a 3.21 × 10^5 Bq 137Cs source. This detector offers a potential single-detector replacement for both neutron and the y-ray detectors in RPM systems.
基金supported in part by National Natural Science Foundation of China(No.11975044&No.81727807)Fundamental Research Funds for the Central Universities(No.FRFTP-19-019A3)+1 种基金Science&Technology on Reliability&Environmental Engineering Laboratory(No.6142004180205)Beijing Nova Program of Science and Technology(No.Z191199991119119).
文摘Purpose Coded-aperture gamma cameras play an important role for homeland security nowadays.They have limitedfield-of-view(FOV)which is a critical parameter for many applications.The FOV can be potentially increased by extending it to the penumbra area(partially coded FOV).Methods In this study,we analyzed this artifact phenomenon based on simulating a commercial coded-aperture gamma camera.The camera uses a modified uniformly redundant array(MURA)mask with a basic pattern of rank 11.Its opening angle of the basic pattern to the detector center is 26.36◦which is the commonly used non-artifact FOV(NAFOV).In some applications,the radiation source is a far-field single-point source.Thus,we extend its FOV to 40◦by including a part of the partially coded area,which is a trade-off between the FOV and image quality.Analytical calculations and simulation studies were carried out.The system matrix was calculated using the Sidden’s algorithm.The maximum likelihood expectation maximization(MLEM)reconstruction method was employed.Projections and reconstruction results of the point source at different positions were compared.The second moment of inertia was used as thefigure of merit.Results Results show that projections have periodic similarity with a period of NAFOV,and reconstructions also have periodic artifacts,i.e.,fromθtoθ+NAFOV.Artifacts are the most serious at the edge of the NAFOV.The upper and lower artifacts are more serious than the left and right artifacts due to the difference between the horizontal centerline(tungsten)and vertical centerline(holes expect the center unit)of the mask.Conclusions For a point source with high activity,artifacts can be reduced by increasing the iteration number of the MLEM reconstruction.Even at the edge of NAFOV,the point source can be possibly reconstructed thanks to the large size of the position sensitive detector(PSD)used.The noise will significantly increase artifacts,which may lead to error locate the point source with low activity at some specific positions.
