In this paper, taking AM-50 Road Heaer as an example, the metheds of structural dynamic modification optimization for road headers are studied using experimental modal analysis and physical parameters analysis. The ma...In this paper, taking AM-50 Road Heaer as an example, the metheds of structural dynamic modification optimization for road headers are studied using experimental modal analysis and physical parameters analysis. The machine’s modal model and lumped mass model are established and the vibration response simulation is calculated for the two models with the load spectral measured. On the above basis, the dynamic parameters of the models are optimised and some useful results have been obtained.The research methods in this paper can be used for the reference to the other lager type mining machines.展开更多
This paper investigates whether security headers are enforced to mitigate cyber-attacks in web-based systems in cyberspace. The security headers examined include X-Content-Type-Options, X-Frame-Options, Strict-Transpo...This paper investigates whether security headers are enforced to mitigate cyber-attacks in web-based systems in cyberspace. The security headers examined include X-Content-Type-Options, X-Frame-Options, Strict-Transport-Security, Referrer-Policy, Content-Security-Policy, and Permissions-Policy. The study employed a controlled experiment using a security header analysis tool. The web-based applications (websites) were analyzed to determine whether security headers have been correctly implemented. The experiment was iterated for 100 universities in Africa which are ranked high. The purposive sampling technique was employed to understand the status quo of the security headers implementations. The results revealed that 70% of the web-based applications in Africa have not enforced security headers in web-based applications. The study proposes a secure system architecture design for addressing web-based applications’ misconfiguration and insecure design. It presents security techniques for securing web-based applications through hardening security headers using automated threat modelling techniques. Furthermore, it recommends adopting the security headers in web-based applications using the proposed secure system architecture design.展开更多
At present, the main attention of researchers is paid to the deterioration of heat transfer when heating the outer surface of the pipe with the liquid or steam, flowing inside it, in the presence of films or deposits ...At present, the main attention of researchers is paid to the deterioration of heat transfer when heating the outer surface of the pipe with the liquid or steam, flowing inside it, in the presence of films or deposits on its inner surface. However, when pipe is heating by heat carrier medium, flowing inside it, film on the inner pipe surface serve a dual protective function, protecting the pipe from corrosion and reducing its thermal stress. The article represents the results of the computational analysis of protective films influence on the thermal stressed state of headers and steam pipelines of combined-cycle power plants (CCPP) heat-recovery steam generators at different transient operating conditions particularly at startups from different initial temperature states and thermal shock. It is shown that protective films have a significant influence on the stresses magnitude and damage accumulation mainly for great temperature disturbances (for thermal shock). Calculations were carried out at various thicknesses of films and assuming that their thermal conductivity less than thermal conductivity of the steam pipelines metal.展开更多
The mechanical stress distribution and the stress concentrations of the superheater outlet header of a 600MW supercritical boiler were analyzed by the finite element method. The results showed that the stress concentr...The mechanical stress distribution and the stress concentrations of the superheater outlet header of a 600MW supercritical boiler were analyzed by the finite element method. The results showed that the stress concentrated at the inside conjunction area between the pipe and the header cylinder , and the value of the maximum mechanical stress concentration factor is 2.51.展开更多
Objective To investigate the flow distribution in plate fin heat exchangers and optimize the design of header configuration for plate fin heat exchangers. Methods A mathematical model of header was proposed. The e...Objective To investigate the flow distribution in plate fin heat exchangers and optimize the design of header configuration for plate fin heat exchangers. Methods A mathematical model of header was proposed. The effects of the header configuration on the flow distribution in plate fin heat exchangers were investigated by CFD. The second header configuration with a two stage distributing structure was brought forward to improve the performance of flow distribution. Results It is found that the flow maldistribution is very serious in the direction of header length for the conventional header used in industry. The numerical predictions indicate that the improved header configurations can effectively improve the performance of flow distribution in plate fin heat exchangers. Conclusion The numerical simulation confirms that CFD should be a suitable tool for predicting the flow distribution. The method has a wide variety of applications in the design of plate fin heat exchangers.展开更多
The difficult problem of automatically welding nipples onto the header is first analyzed in this paper, and then the overall structure and operating principle of the robot working unit are introduced. The robot and th...The difficult problem of automatically welding nipples onto the header is first analyzed in this paper, and then the overall structure and operating principle of the robot working unit are introduced. The robot and the measuring device are located by employing the traveling lorry, and this unit enables the robot to adjust the tracks according to the errors received from the measuring device, and then the nipples are welded properly. This paper emphases on the development of the master-slave control system, in which the prograrmmable Logic Controller (PLC) is used as the master computer.展开更多
Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the re...Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the relocation of mobile sensors is the most desirable method to recover the sensing holes.The previous research conducted by the authors so far demonstrated the most realistic hopping sensor relocation scheme,which is suitable for the distributed environment.In previous studies,the cluster header plays an essential role in detecting the sensing hole and requesting the neighboring cluster to recover the sensing hole that occurred in the sensor node.However,the limitations of the cluster header in the previously proposed relocation protocol are not fully considered.Because the cluster header jumps more frequently than non-header nodes,its energy con-sumption is relatively high compared to other nodes.Therefore,it is most likely to lead to header node failure and can lead to data loss on the network.In this paper,the jumping ability and energy consumption of the cluster header are seriously considered.Additional ability to replace cluster headers in case of failure is also implemented.Simulation results show that the data collection time can be further increased,which demonstrates the validity of the proposed algorithms.展开更多
One aspect of cybersecurity,incorporates the study of Portable Executables(PE)files maleficence.Artificial Intelligence(AI)can be employed in such studies,since AI has the ability to discriminate benign from malicious...One aspect of cybersecurity,incorporates the study of Portable Executables(PE)files maleficence.Artificial Intelligence(AI)can be employed in such studies,since AI has the ability to discriminate benign from malicious files.In this study,an exclusive set of 29 features was collected from trusted implementations,this set was used as a baseline to analyze the presented work in this research.A Decision Tree(DT)and Neural Network Multi-Layer Perceptron(NN-MLPC)algorithms were utilized during this work.Both algorithms were chosen after testing a few diverse procedures.This work implements a method of subgrouping features to answer questions such as,which feature has a positive impact on accuracy when added?Is it possible to determine a reliable feature set to distinguish a malicious PE file from a benign one?when combining features,would it have any effect on malware detection accuracy in a PE file?Results obtained using the proposed method were improved and carried few observations.Generally,the obtained results had practical and numerical parts,for the practical part,the number of features and which features included are the main factors impacting the calculated accuracy,also,the combination of features is as crucial in these calculations.Numerical results included,finding accuracies with enhanced values,for example,NN_MLPC attained 0.979 and 0.98;for DT an accuracy of 0.9825 and 0.986 was attained.展开更多
In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and tool.It exposed the intrinsic flaws of t...In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and tool.It exposed the intrinsic flaws of the widely used road header.The problemis that it was designed according to early timbering support state but is not suitable forrock bolt technology.The way to improve the function of existing road headers is notthrough parallel operations but using the SUDM (Shield Union Driving Machine), which isa new machine that improves construction.This article proposed a few solutions in designto solve this problem.展开更多
In recent years, Hyper Text Transfer Protocol （HTTP） spreads quickly and steadily in the usage of mobile applications as a common web protocol, so that the mobile applications can also benefit from HTTP/2, which is ...In recent years, Hyper Text Transfer Protocol （HTTP） spreads quickly and steadily in the usage of mobile applications as a common web protocol, so that the mobile applications can also benefit from HTTP/2, which is the new version of HTTP based on SPDY developed by Google to speed up the Internet transmission speed. HTTP/2 enables a more efficient use of network resources and a reduced perception of latency by in- troducing header field compression and allowing multiple concurrent exchanges on the same connection. However, what H3TP/2 focuses on is visiting websites through a browser, and mobile applications are not considered much. In this paper, firstly, mobile applications are classified based on the da- ta flow characteristics. Based on the classification, we propose an optimization of HTTP/2 for mobile applications, called HTTP/2-Advance, which uses multiple Transmission Control Protocol （TCP） connections to multiplex HTYP requests and responses. Then we build a tiny system which simulates actu- al requests and responses between mobile applications and servers. We figure out the best choice of the number of multiple TCP connections for mobile applications, and compare the performance of HTTP, HTTP/2 and HTrP/2-Advance in both simulated and in-situ experiments in our system.展开更多
Two main types of in situ grain harvesttng machine are introduced. The comparison of their working principles and advantages are given. The limitations and prospects for stripper header are discussed.
To meet the actual requirements of an automotive industry chain collaboration platform （AICCP）, this paper offers several simple but effective security policies based upon the traditional security mechanism of data ...To meet the actual requirements of an automotive industry chain collaboration platform （AICCP）, this paper offers several simple but effective security policies based upon the traditional security mechanism of data transfer, including user ID verification with SOAP （simple object access protocol）, header, SOAP message encryption with SOAP extension and XML （extensible markup language） file encryption and decryption. Application of these policies to the AICCP for more than one year proves the effectiveness of the data exchange practice between the AICCP and enterprise Intranet.展开更多
Over the last decades, email has been the major carrier for transporting spam and malicious contents over the network. Email is also the primary source of numerous criminal activities on the Internet. Computer Forensi...Over the last decades, email has been the major carrier for transporting spam and malicious contents over the network. Email is also the primary source of numerous criminal activities on the Internet. Computer Forensics is a systematic process to retain and analyze saved emails for the purpose of legal proceedings and other civil matters. Email analysis is challenging due to not only various fields that can be forged by hackers or malicious users, but also the flexibility of composing, editing, deleting of emails using offline (e.g., MS Outlook) or online (e.g., Web mail) email applications. Towards this direction, a number of open source forensics tools have been widely used by the practitioners. However, these tools have been developed in an isolated manner rather than a collaborative approach. Given that email forensic tool users need to understand to what extent a tool would be useful for his/her circumstances and conducting forensic analysis accordingly. In this paper, we examine a set of common features to compare and contrast five popular open source email forensic tools. The study finds that all email forensic tools are not similar, offer diverse types of facility. By combining analysis tools, it may be possible to gain detailed information in the area of email forensic.展开更多
文摘In this paper, taking AM-50 Road Heaer as an example, the metheds of structural dynamic modification optimization for road headers are studied using experimental modal analysis and physical parameters analysis. The machine’s modal model and lumped mass model are established and the vibration response simulation is calculated for the two models with the load spectral measured. On the above basis, the dynamic parameters of the models are optimised and some useful results have been obtained.The research methods in this paper can be used for the reference to the other lager type mining machines.
文摘This paper investigates whether security headers are enforced to mitigate cyber-attacks in web-based systems in cyberspace. The security headers examined include X-Content-Type-Options, X-Frame-Options, Strict-Transport-Security, Referrer-Policy, Content-Security-Policy, and Permissions-Policy. The study employed a controlled experiment using a security header analysis tool. The web-based applications (websites) were analyzed to determine whether security headers have been correctly implemented. The experiment was iterated for 100 universities in Africa which are ranked high. The purposive sampling technique was employed to understand the status quo of the security headers implementations. The results revealed that 70% of the web-based applications in Africa have not enforced security headers in web-based applications. The study proposes a secure system architecture design for addressing web-based applications’ misconfiguration and insecure design. It presents security techniques for securing web-based applications through hardening security headers using automated threat modelling techniques. Furthermore, it recommends adopting the security headers in web-based applications using the proposed secure system architecture design.
文摘At present, the main attention of researchers is paid to the deterioration of heat transfer when heating the outer surface of the pipe with the liquid or steam, flowing inside it, in the presence of films or deposits on its inner surface. However, when pipe is heating by heat carrier medium, flowing inside it, film on the inner pipe surface serve a dual protective function, protecting the pipe from corrosion and reducing its thermal stress. The article represents the results of the computational analysis of protective films influence on the thermal stressed state of headers and steam pipelines of combined-cycle power plants (CCPP) heat-recovery steam generators at different transient operating conditions particularly at startups from different initial temperature states and thermal shock. It is shown that protective films have a significant influence on the stresses magnitude and damage accumulation mainly for great temperature disturbances (for thermal shock). Calculations were carried out at various thicknesses of films and assuming that their thermal conductivity less than thermal conductivity of the steam pipelines metal.
文摘The mechanical stress distribution and the stress concentrations of the superheater outlet header of a 600MW supercritical boiler were analyzed by the finite element method. The results showed that the stress concentrated at the inside conjunction area between the pipe and the header cylinder , and the value of the maximum mechanical stress concentration factor is 2.51.
文摘Objective To investigate the flow distribution in plate fin heat exchangers and optimize the design of header configuration for plate fin heat exchangers. Methods A mathematical model of header was proposed. The effects of the header configuration on the flow distribution in plate fin heat exchangers were investigated by CFD. The second header configuration with a two stage distributing structure was brought forward to improve the performance of flow distribution. Results It is found that the flow maldistribution is very serious in the direction of header length for the conventional header used in industry. The numerical predictions indicate that the improved header configurations can effectively improve the performance of flow distribution in plate fin heat exchangers. Conclusion The numerical simulation confirms that CFD should be a suitable tool for predicting the flow distribution. The method has a wide variety of applications in the design of plate fin heat exchangers.
文摘The difficult problem of automatically welding nipples onto the header is first analyzed in this paper, and then the overall structure and operating principle of the robot working unit are introduced. The robot and the measuring device are located by employing the traveling lorry, and this unit enables the robot to adjust the tracks according to the errors received from the measuring device, and then the nipples are welded properly. This paper emphases on the development of the master-slave control system, in which the prograrmmable Logic Controller (PLC) is used as the master computer.
基金supported by Incheon National University Research Grant in 2020(2020–0437)。
文摘Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the relocation of mobile sensors is the most desirable method to recover the sensing holes.The previous research conducted by the authors so far demonstrated the most realistic hopping sensor relocation scheme,which is suitable for the distributed environment.In previous studies,the cluster header plays an essential role in detecting the sensing hole and requesting the neighboring cluster to recover the sensing hole that occurred in the sensor node.However,the limitations of the cluster header in the previously proposed relocation protocol are not fully considered.Because the cluster header jumps more frequently than non-header nodes,its energy con-sumption is relatively high compared to other nodes.Therefore,it is most likely to lead to header node failure and can lead to data loss on the network.In this paper,the jumping ability and energy consumption of the cluster header are seriously considered.Additional ability to replace cluster headers in case of failure is also implemented.Simulation results show that the data collection time can be further increased,which demonstrates the validity of the proposed algorithms.
文摘One aspect of cybersecurity,incorporates the study of Portable Executables(PE)files maleficence.Artificial Intelligence(AI)can be employed in such studies,since AI has the ability to discriminate benign from malicious files.In this study,an exclusive set of 29 features was collected from trusted implementations,this set was used as a baseline to analyze the presented work in this research.A Decision Tree(DT)and Neural Network Multi-Layer Perceptron(NN-MLPC)algorithms were utilized during this work.Both algorithms were chosen after testing a few diverse procedures.This work implements a method of subgrouping features to answer questions such as,which feature has a positive impact on accuracy when added?Is it possible to determine a reliable feature set to distinguish a malicious PE file from a benign one?when combining features,would it have any effect on malware detection accuracy in a PE file?Results obtained using the proposed method were improved and carried few observations.Generally,the obtained results had practical and numerical parts,for the practical part,the number of features and which features included are the main factors impacting the calculated accuracy,also,the combination of features is as crucial in these calculations.Numerical results included,finding accuracies with enhanced values,for example,NN_MLPC attained 0.979 and 0.98;for DT an accuracy of 0.9825 and 0.986 was attained.
文摘In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and tool.It exposed the intrinsic flaws of the widely used road header.The problemis that it was designed according to early timbering support state but is not suitable forrock bolt technology.The way to improve the function of existing road headers is notthrough parallel operations but using the SUDM (Shield Union Driving Machine), which isa new machine that improves construction.This article proposed a few solutions in designto solve this problem.
文摘In recent years, Hyper Text Transfer Protocol （HTTP） spreads quickly and steadily in the usage of mobile applications as a common web protocol, so that the mobile applications can also benefit from HTTP/2, which is the new version of HTTP based on SPDY developed by Google to speed up the Internet transmission speed. HTTP/2 enables a more efficient use of network resources and a reduced perception of latency by in- troducing header field compression and allowing multiple concurrent exchanges on the same connection. However, what H3TP/2 focuses on is visiting websites through a browser, and mobile applications are not considered much. In this paper, firstly, mobile applications are classified based on the da- ta flow characteristics. Based on the classification, we propose an optimization of HTTP/2 for mobile applications, called HTTP/2-Advance, which uses multiple Transmission Control Protocol （TCP） connections to multiplex HTYP requests and responses. Then we build a tiny system which simulates actu- al requests and responses between mobile applications and servers. We figure out the best choice of the number of multiple TCP connections for mobile applications, and compare the performance of HTTP, HTTP/2 and HTrP/2-Advance in both simulated and in-situ experiments in our system.
文摘Two main types of in situ grain harvesttng machine are introduced. The comparison of their working principles and advantages are given. The limitations and prospects for stripper header are discussed.
基金National High-Tech Research and De-velopment Program of China (863 Program) (No2004AA414010)Science Technology Project of Sichuan Province(No2006z03-015)
文摘To meet the actual requirements of an automotive industry chain collaboration platform （AICCP）, this paper offers several simple but effective security policies based upon the traditional security mechanism of data transfer, including user ID verification with SOAP （simple object access protocol）, header, SOAP message encryption with SOAP extension and XML （extensible markup language） file encryption and decryption. Application of these policies to the AICCP for more than one year proves the effectiveness of the data exchange practice between the AICCP and enterprise Intranet.
文摘Over the last decades, email has been the major carrier for transporting spam and malicious contents over the network. Email is also the primary source of numerous criminal activities on the Internet. Computer Forensics is a systematic process to retain and analyze saved emails for the purpose of legal proceedings and other civil matters. Email analysis is challenging due to not only various fields that can be forged by hackers or malicious users, but also the flexibility of composing, editing, deleting of emails using offline (e.g., MS Outlook) or online (e.g., Web mail) email applications. Towards this direction, a number of open source forensics tools have been widely used by the practitioners. However, these tools have been developed in an isolated manner rather than a collaborative approach. Given that email forensic tool users need to understand to what extent a tool would be useful for his/her circumstances and conducting forensic analysis accordingly. In this paper, we examine a set of common features to compare and contrast five popular open source email forensic tools. The study finds that all email forensic tools are not similar, offer diverse types of facility. By combining analysis tools, it may be possible to gain detailed information in the area of email forensic.
