Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with mi...Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network(DFN) for each discontinuity set. I-site studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.展开更多
Static assignment of IP addresses or identifiers can be exploited by an adversary to attack a network. However, existing dynamic IP address assignment approaches suffer from two limitations, namely: participation of t...Static assignment of IP addresses or identifiers can be exploited by an adversary to attack a network. However, existing dynamic IP address assignment approaches suffer from two limitations, namely: participation of terminals in the assignment and inadequate network server management. Thus, in this paper, we propose an Overall-transparent Dynamic Identifier-mapping Mechanism(ODIM) to manage the identifier of network nodes to defend against scanning and worm propagation in the Smart Identifier NETwork(SINET). We establish the selection and allocation constraints, and present selection and allocation algorithms to determine the constraints. The non-repetition probability and cover cycle allow us to evaluate the defense efficiency against scanning. We propose the probability for routing identifiers and derive the defense efficiency of ODIM against worm propagation. Simulation results and theoretical analysis show that the proposed method effectively reduces the detection probability of Routing IDentifiers(RIDs) and thus improves defense capabilities against worm propagation.展开更多
Early detection of lung nodule is of great importance for the successful diagnosis and treatment of lung cancer. Many researchers have tried with diverse methods, such as thresholding, computer-aided diagnosis system,...Early detection of lung nodule is of great importance for the successful diagnosis and treatment of lung cancer. Many researchers have tried with diverse methods, such as thresholding, computer-aided diagnosis system, pattern recognition technique, backpropagation algorithm, etc. Recently, convolutional neural network (CNN) finds promising applications in many areas. In this research, we investigated 3D CNN to detect early lung cancer using LUNA 16 dataset. At first, we preprocessed raw image using thresholding technique. Then we used Vanilla 3D CNN classifier to determine whether the image is cancerous or non-cancerous. The experimental results show that the proposed method can achieve a detection accuracy of about 80% and it is a satisfactory performance compared to the existing technique.展开更多
Pattern matching is a fundamental approach to detect malicious behaviors and information over Internet, which has been gradually used in high-speed network traffic analysis. However, there is a performance bottleneck ...Pattern matching is a fundamental approach to detect malicious behaviors and information over Internet, which has been gradually used in high-speed network traffic analysis. However, there is a performance bottleneck for multi-pattern matching on online compressed network traffic(CNT), this is because malicious and intrusion codes are often embedded into compressed network traffic. In this paper, we propose an online fast and multi-pattern matching algorithm on compressed network traffic(FMMCN). FMMCN employs two types of jumping, i.e. jumping during sliding window and a string jump scanning strategy to skip unnecessary compressed bytes. Moreover, FMMCN has the ability to efficiently process multiple large volume of networks such as HTTP traffic, vehicles traffic, and other Internet-based services. The experimental results show that FMMCN can ignore more than 89.5% of bytes, and its maximum speed reaches 176.470MB/s in a midrange switches device, which is faster than the current fastest algorithm ACCH by almost 73.15 MB/s.展开更多
Detection of port scan is an important component in a network intrusion detection and prevention system. Traditional statistical methods can be easily evaded by stealthy scans and are prone to DoS attacks. This paper ...Detection of port scan is an important component in a network intrusion detection and prevention system. Traditional statistical methods can be easily evaded by stealthy scans and are prone to DoS attacks. This paper presents a new mechanism termed PSD(port scan detection), which is based on TCP packet anomaly evaluation. By learning the port distribution and flags of TCP packets arriving at the protected hosts, PSD can compute the anomaly score of each packet and effectively detect port scans including slow scans and stealthy scans. Experiments show that PSD has high detection accuracy and low detection latency.展开更多
Along with the deepening of the reform and opening-up policy and the entering of the WTO,international exchange of economy and culture has become more and more frequent,Internet has become an indispensable part of our...Along with the deepening of the reform and opening-up policy and the entering of the WTO,international exchange of economy and culture has become more and more frequent,Internet has become an indispensable part of our life,its rapid development brings great convenience to us,and all of the computers will be connected by Internet in the 21 century,thus the meaning of information security has changed substantially.It not only changes from a general guarding to a common defence,but from a specific field to a public subject as well.However,the opening and sharing of the Internet resource,unefficient supervision as well as various virus make people's information and belongings being in an extremely dangerous environment.The fight between hackers and anti-hackers,destruction and anti-destruction has already affected the stable running of the network and users' legal right,caused great economy damages and it could also threat our country's security.So a right understanding and in-time measures should be paid special attention to.The thesis firstly expatiates the current state of the network security and its importance,and discusses some major factors and threats that affect the network security.And the thesis also introduce some catalogues of the security techniques,some relevant information and their major characters,besides that,I enumerate some popular and effective methods of protecting our network,including the widely used firewall,and the meticulous techniques such as security scan techniques and techniques of intrusion detection.Lastly,some protective measures are stated.展开更多
以鄂尔多斯盆地某区块的砂泥夹层岩心为研究对象,使用基于小波变换的去噪神经网络(denoising neural network based on wavelet transformation,DWTNet)对于岩心的图像进行去噪研究。该方法的评断结果采用峰值信噪比(peak signal to noi...以鄂尔多斯盆地某区块的砂泥夹层岩心为研究对象,使用基于小波变换的去噪神经网络(denoising neural network based on wavelet transformation,DWTNet)对于岩心的图像进行去噪研究。该方法的评断结果采用峰值信噪比(peak signal to noise ratio,PSNR)和去噪后的图像结果进行了对比。研究表明,利用DWTNet在测试集YX1、YX2测试所提出的算法,并与EGDNet等去噪算法进行对比,PSNR在噪声为25、50、75 dB时,高于EGDNet算法0.527、0.418、1.1 dB。所提的算法在峰值信噪比等指标均高于其他算法;并在视觉效果上其处理得到的图像也更加清晰。方法的提出对于孔隙度、平均体积比表面积、平均曲率计算等都有着非常重要的意义。展开更多
基金funded by the NIOSH Mining Program under Contract No. 200-2016-91300
文摘Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network(DFN) for each discontinuity set. I-site studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.
文摘Static assignment of IP addresses or identifiers can be exploited by an adversary to attack a network. However, existing dynamic IP address assignment approaches suffer from two limitations, namely: participation of terminals in the assignment and inadequate network server management. Thus, in this paper, we propose an Overall-transparent Dynamic Identifier-mapping Mechanism(ODIM) to manage the identifier of network nodes to defend against scanning and worm propagation in the Smart Identifier NETwork(SINET). We establish the selection and allocation constraints, and present selection and allocation algorithms to determine the constraints. The non-repetition probability and cover cycle allow us to evaluate the defense efficiency against scanning. We propose the probability for routing identifiers and derive the defense efficiency of ODIM against worm propagation. Simulation results and theoretical analysis show that the proposed method effectively reduces the detection probability of Routing IDentifiers(RIDs) and thus improves defense capabilities against worm propagation.
文摘Early detection of lung nodule is of great importance for the successful diagnosis and treatment of lung cancer. Many researchers have tried with diverse methods, such as thresholding, computer-aided diagnosis system, pattern recognition technique, backpropagation algorithm, etc. Recently, convolutional neural network (CNN) finds promising applications in many areas. In this research, we investigated 3D CNN to detect early lung cancer using LUNA 16 dataset. At first, we preprocessed raw image using thresholding technique. Then we used Vanilla 3D CNN classifier to determine whether the image is cancerous or non-cancerous. The experimental results show that the proposed method can achieve a detection accuracy of about 80% and it is a satisfactory performance compared to the existing technique.
基金supported by China MOST project (No.2012BAH46B04)
文摘Pattern matching is a fundamental approach to detect malicious behaviors and information over Internet, which has been gradually used in high-speed network traffic analysis. However, there is a performance bottleneck for multi-pattern matching on online compressed network traffic(CNT), this is because malicious and intrusion codes are often embedded into compressed network traffic. In this paper, we propose an online fast and multi-pattern matching algorithm on compressed network traffic(FMMCN). FMMCN employs two types of jumping, i.e. jumping during sliding window and a string jump scanning strategy to skip unnecessary compressed bytes. Moreover, FMMCN has the ability to efficiently process multiple large volume of networks such as HTTP traffic, vehicles traffic, and other Internet-based services. The experimental results show that FMMCN can ignore more than 89.5% of bytes, and its maximum speed reaches 176.470MB/s in a midrange switches device, which is faster than the current fastest algorithm ACCH by almost 73.15 MB/s.
文摘Detection of port scan is an important component in a network intrusion detection and prevention system. Traditional statistical methods can be easily evaded by stealthy scans and are prone to DoS attacks. This paper presents a new mechanism termed PSD(port scan detection), which is based on TCP packet anomaly evaluation. By learning the port distribution and flags of TCP packets arriving at the protected hosts, PSD can compute the anomaly score of each packet and effectively detect port scans including slow scans and stealthy scans. Experiments show that PSD has high detection accuracy and low detection latency.
文摘Along with the deepening of the reform and opening-up policy and the entering of the WTO,international exchange of economy and culture has become more and more frequent,Internet has become an indispensable part of our life,its rapid development brings great convenience to us,and all of the computers will be connected by Internet in the 21 century,thus the meaning of information security has changed substantially.It not only changes from a general guarding to a common defence,but from a specific field to a public subject as well.However,the opening and sharing of the Internet resource,unefficient supervision as well as various virus make people's information and belongings being in an extremely dangerous environment.The fight between hackers and anti-hackers,destruction and anti-destruction has already affected the stable running of the network and users' legal right,caused great economy damages and it could also threat our country's security.So a right understanding and in-time measures should be paid special attention to.The thesis firstly expatiates the current state of the network security and its importance,and discusses some major factors and threats that affect the network security.And the thesis also introduce some catalogues of the security techniques,some relevant information and their major characters,besides that,I enumerate some popular and effective methods of protecting our network,including the widely used firewall,and the meticulous techniques such as security scan techniques and techniques of intrusion detection.Lastly,some protective measures are stated.
文摘以鄂尔多斯盆地某区块的砂泥夹层岩心为研究对象,使用基于小波变换的去噪神经网络(denoising neural network based on wavelet transformation,DWTNet)对于岩心的图像进行去噪研究。该方法的评断结果采用峰值信噪比(peak signal to noise ratio,PSNR)和去噪后的图像结果进行了对比。研究表明,利用DWTNet在测试集YX1、YX2测试所提出的算法,并与EGDNet等去噪算法进行对比,PSNR在噪声为25、50、75 dB时,高于EGDNet算法0.527、0.418、1.1 dB。所提的算法在峰值信噪比等指标均高于其他算法;并在视觉效果上其处理得到的图像也更加清晰。方法的提出对于孔隙度、平均体积比表面积、平均曲率计算等都有着非常重要的意义。
