To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-sha...To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-shaped flaws are subjected to uniaxial compressive tests under different F-T cycles.Experimental observations show that the uniaxial compressive strength of specimens are significantly influenced by F-T cycles and their failure modes are mainly affected by the central angleαof the prefabricated flaws.Unlike the specimens with a central angle of 60°,the specimens with a central angle of 120°and 180°have greater curvature of flaws,so tensile cracks occur in the arc-top area of their prefabricated flaws.According to experimental images observed by environmental scanning electron microscope(ESEM),as the number of F-T cycles increases,the deterioration effect of the specimen becomes more obvious,which is specifically reflected in the increase of the mass loss,peak stress loss,and damage variables as a power function,and the peak strain decreases as a quadratic polynomial.According to numerical results using two-dimensional particle flow code(PFC2D),it is found that F-T cycles cause more damage to the specimen in the early stages than in the later ones.The area of the concentrated compressive stress zone in the middle is decreased due to the increased number of F-T cycles,while the area of the surrounding tensile-shear stress zone is increased.The models appear different failure modes due to the release of concentrated stress in different tensile-shear zones.展开更多
The R F first order second moment method will produce more error for calculating the reliability of welded engineering pipe structures when the failure function is seriously nonlinear and the random variables don...The R F first order second moment method will produce more error for calculating the reliability of welded engineering pipe structures when the failure function is seriously nonlinear and the random variables don′t serve as normal distribution. In order to increase the computing accuracy of reliability, an improved FOSM method is used for calculating the failure probability of welded pipes with flaws in this paper. Because of solving the problems of the linear expansion of failure function at the failure point and constructing equivalent normal variables, the new algorithm can greatly improve the calculating accuracy of probability of the welded pipes with cracks. The examples show that this method is simple, efficient and accurate for reliability safety assessment of the welded pipes with cracks. It can save more time than the Monte Carlo method does, so that the improved FOSM method is recommended for engineering reliability safety assessment of the welded pipes with flaws.展开更多
Based on the axial stress-axial strain curves,the effect of fissure angle on the strength and deformation behavior of sandstone specimens containing combined flaws is analyzed.The mechanical parameters of sandstone sp...Based on the axial stress-axial strain curves,the effect of fissure angle on the strength and deformation behavior of sandstone specimens containing combined flaws is analyzed.The mechanical parameters of sandstone specimens containing combined flaws are all lower than that of intact specimen,but the reduction extent is distinctly related to the fissure angle.The results of sandstone specimens containing combined flaws are obtained by the acoustic emission,which can be used to monitor the crack initiation and propagation.The ultimate failure mode and crack coalescence behavior are evaluated for brittle sandstone specimens containing combined flaws.Nine different crack types are identified on the basis of their geometry and crack coalescence mechanism(tensile crack,hole collapse,far-field crack and surface spalling)for combined flaws.The photographic monitoring was also adopted for uniaxial compression test in order to confirm the sequence of crack coalescence in brittle sandstone specimens containing combined flaws,which recorded the real-time crack coalescence process during entire deformation.According to the monitored results,the effect of crack coalescence process on the strength and deformation behavior is investigated based on a detailed analysis for brittle sandstone specimens containing combined flaws by using digital photogrammetry.展开更多
Failure of rock mass that is subjected to compressive loads occurs from initiation, propagation, and linkage of new cracks from preexisting fissures. Our research investigates the cracking behaviour and coalescence pr...Failure of rock mass that is subjected to compressive loads occurs from initiation, propagation, and linkage of new cracks from preexisting fissures. Our research investigates the cracking behaviour and coalescence process in a brittle material with two non-parallel overlapping flaws using a high-speed camera. The coalescence tensile crack and tensile wing cracks were the first cracks to occur from the preexisting flaws. The initiation stresses of the primary cracks at the two tips of each flaw were simultaneous and decreased with reduced flaw inclination angle. The following types of coalescence cracks were identified between the flaws: primary tensile coalescence crack, tensile crack linkage, shear crack linkage, mixed tensile-shear crack, and indirect crack coalescence. Coalescence through tensile linkage occurred mostly at pre-peak stress. In contrast, coalescence through shear or mixed tensile-shear cracks occurred at higher stress. Overall, this study indicates that the geometry of preexisting flaws affect crack initiation and coalescence behaviour.展开更多
In the October 2014 edition of JAMA, Dr. Hinman and her colleagues published an acupuncture clinical trial entitled Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial＂ and concluded that in patients olde...In the October 2014 edition of JAMA, Dr. Hinman and her colleagues published an acupuncture clinical trial entitled Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial＂ and concluded that in patients older than 50 years with moderate or severe chronic knee pain, neither laser nor needle acupuncture conferred benefit over sham for pain or function. Our findings do not support acupuncture for these patients[1].展开更多
In the October 2014 publication of JAMA, Dr. Hinman and colleagues published the study “Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial,” which concluded that in patients older than 50 years with mod...In the October 2014 publication of JAMA, Dr. Hinman and colleagues published the study “Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial,” which concluded that in patients older than 50 years with moderate or severe chronic knee pain, neither laser nor needle acupuncture conferred benefit over sham for pain or function. Our findings do not support acupuncture for these patients.展开更多
CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractu...CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.展开更多
Emma is the heroine of one of the novels written by Jane Austen(1775-1817) who is among the most widely read writers in English literature.In the novel,also named Emma,Austen portrayed Emma as a young,pretty and smart...Emma is the heroine of one of the novels written by Jane Austen(1775-1817) who is among the most widely read writers in English literature.In the novel,also named Emma,Austen portrayed Emma as a young,pretty and smart gentlewoman,yet she was not a perfect or flawless character.She dose not seem to have any sense of her own limitations.Her self-conceit and meddling nature are two of her most fatal character flaws.In this article,we will give a detailed analysis of Emma's flaws supported by various incidents as the novel progresses.We will also find out the two major factors that contribute to develop these character flaws,which are the negative effects caused on her by people very close to her and also the society of her time.展开更多
In the October 2014 publication of JAMA,Dr.Hinman and colleagues published the study＂Acupuncture for Chronic Knee Pain：A Randomized Clinical Trial,＂in which the authors concluded that＂in patients older than50 year...In the October 2014 publication of JAMA,Dr.Hinman and colleagues published the study＂Acupuncture for Chronic Knee Pain：A Randomized Clinical Trial,＂in which the authors concluded that＂in patients older than50 years with moderate or severe chronic knee pain,neither laser nor needle acupuncture conferred benefi t over sham for pain or function.Our fi ndings do not support acupuncture[1]展开更多
Hamlet is the most discussed of Shakespeare's tragedies, while The Great Gatsby is the masterpiece of Fitzgerald. It is true that the tragic flaws of the protagonists would be a key factor driving the development ...Hamlet is the most discussed of Shakespeare's tragedies, while The Great Gatsby is the masterpiece of Fitzgerald. It is true that the tragic flaws of the protagonists would be a key factor driving the development of the plots. In these two dramas, the flaws of the protagonists leaded to their tragic endings which are related to their own characteristics of the protagonists. And the ends of the stories are with the tragedies.展开更多
Digital in the daily life of companies undeniably leads them to use services and applications of all kinds. Companies in their permanent quest for the exchange of information devote themselves to the use of the Intern...Digital in the daily life of companies undeniably leads them to use services and applications of all kinds. Companies in their permanent quest for the exchange of information devote themselves to the use of the Internet which nowadays constitutes an open door for the birth of several types of faults, some of which are unknown to certain digital professionals in the field. Corporate. The purpose of this research is to show the probable existence of digital security flaws in the daily activities carried out by companies in Burkina Faso. In companies in Burkina Faso, we seem to see a way of working that does not respect the standards and safety standards prescribed by ISO 27001. We seem to see a way of working based on the result of the gain and not on the securities measures and integrity of critical data, data confidentiality, management and prevention of possible security risks related to their activities. We seem to be witnessing in companies the immanent presence of faults which could be the work of the users of the system, of the infrastructure used which is outdated or badly configured, of software anomalies linked to programming errors, and to poor implementation of the security policy within the companies. This research is important because it exposes the handicaps that companies have in terms of digital security. The expected result is to bring out existing flaws that are not taken seriously by IT staff and propose possible solutions to overcome these security risks.展开更多
The Spanish Tragedy, written by Thomas Kyd in the late 1580 s, was the grandfather of all revenge tragedies. It established a new genre named revenge tragedy in English theater. Its well-developed characters, timeless...The Spanish Tragedy, written by Thomas Kyd in the late 1580 s, was the grandfather of all revenge tragedies. It established a new genre named revenge tragedy in English theater. Its well-developed characters, timeless themes, dramatic intrigue and pioneering adoption of blank verse enabled it to be viewed as a classic of London theater. Yet it also has received criticisms over the past centuries. Based on Aristotle's opinion of a perfect tragedy in"Poetics", this paper aims to point out the flaws of the play from five perspectives: the fate of Hieronimo, the cause of it, Bel-imperia's sudden love for Horatio, subplot concerning Villuppo and Alexandro, the discovery and the diction.展开更多
In the mid-1980’s researchers at Cleveland State University made a startling discovery. They conducted an experiment by creating two fictitious job candidates—David and John.Thecandidates had identical resumes and l...In the mid-1980’s researchers at Cleveland State University made a startling discovery. They conducted an experiment by creating two fictitious job candidates—David and John.Thecandidates had identical resumes and letters of reference.The only difference was that John’s letterincluded the sentence“Sometimes,John can be difficult to get along with.”They showed the re-展开更多
We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consiste...We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consistent with the original one. This study is very helpful to further enhance the infrared glass flaw inspection technique.展开更多
Logic flaws within web applications will allow malicious operations to be triggered towards back-end database. Existing approaches to identifying logic flaws of database accesses are strongly tied to structured query ...Logic flaws within web applications will allow malicious operations to be triggered towards back-end database. Existing approaches to identifying logic flaws of database accesses are strongly tied to structured query language （SQL） statement construction and cannot be applied to the new generation of web applications that use not only structured query language （NoSQL） databases as the storage tier. In this paper, we present Lom, a black-box approach for discovering many categories of logic flaws within MongoDB- based web applications. Our approach introduces a MongoDB operation model to support new features of MongoDB and models the application logic as a mealy finite state machine. During the testing phase, test inputs which emulate state violation attacks are constructed for identifying logic flaws at each application state. We apply Lom to several MongoDB-based web applications and demonstrate its effectiveness.展开更多
To give an insight into the understanding of damage evolution and crack propagation in rocks,a series of uniaxial and biaxial compression numerical tests are carried out.The investigations show that damage evolution o...To give an insight into the understanding of damage evolution and crack propagation in rocks,a series of uniaxial and biaxial compression numerical tests are carried out.The investigations show that damage evolution occurs firstly in the weak rock,the area around the flaw and the area between the flaw and the neighboring rock layer.Cracks mostly generate as tensile cracks under uniaxial compression and shear cracks under biaxial compression.Crack patterns are classified and divided.The relationship between the accumulated lateral displacement and the short radius（b）is fitted,and the equation of crack path is also established.展开更多
In this paper,a modified genetic local search algorithm(MGLSA) is proposed.The proposed algorithm is resulted from employing the simulated annealing technique to regulate the variance of the Gaussian mutation of the g...In this paper,a modified genetic local search algorithm(MGLSA) is proposed.The proposed algorithm is resulted from employing the simulated annealing technique to regulate the variance of the Gaussian mutation of the genetic local search algorithm(GLSA).Then,an MGLSA-based inverse algorithm is proposed for magnetic flux leakage(MFL) signal inversion of corrosive flaws,in which the MGLSA is used to solve the optimization problem in the MFL inverse problem.Experimental results demonstrate that the MGLSA-based inverse algorithm is more robust than GLSA-based inverse algorithm in the presence of noise in the measured MFL signals.展开更多
This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accomp...This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accompanying Test (EAT) algorithm in this paper. Two propositions in algebraic topology are presented, which are the foundation of the EAT algorithm. As the modeling is the first step for rendering in the animation and visualization, or computer-aided design (CAD) in related applications, the flaws can bring some serious problems in the final image or product, such as an artificial sense in animation rendering or a mistaken product in industry. To verify the EAT progressive procedure, a three-dimensional (3D) stamp model is constructed. The modeling process is accompanied by the EAT procedure. The EAT scheme is verified as the flaws in the stamp model are found and modified.展开更多
Structural internal flaws often weaken the performance and integral stability,while traditional nondestructive testing or inversion methods face challenges of high cost and low efficiency in quantitative flaw identifi...Structural internal flaws often weaken the performance and integral stability,while traditional nondestructive testing or inversion methods face challenges of high cost and low efficiency in quantitative flaw identification.To quickly identify internal flaws within structures,a deep learning model for flaw detection is proposed based on the image quadtree scaled boundary finite element method(SBFEM)combined with a deep neural network(DNN).The training dataset is generated fromthe numerical simulations using the balanced quadtree algorithmand SBFEM,where the structural domain is discretized based on recursive decomposition principles andmesh refinement is automatically performed in the flaw boundary regions.The model contains only six types of elements and hanging nodes don’t affect the solution accuracy,resulting in a high degree of automation and significantly reducing the cost of the training dataset.The deep artificial neural network for flaw detection is constructed using DNN as the learning framework,effectively mitigating the risk of the objective function converging to local optima during training.Statistical methods are employed to evaluate the accuracy of the inversionmodel,and the influences of flaw size and the number of training samples on the performance are examined.In statistical results of single flaw,the 95%confidence intervals of the relative error for(x,y,r)are[2.16%,2.76%],[1.53%,1.96%]and[1.49%,1.91%],respectively.The 95%confidence interval of the comprehensive relative error for double flaws is[3.06%,3.62%].The results demonstrate that the predicted flaw parameters align closely with the reserved clean data,indicating that themodel can accurately quantify both the location and size of structural flaws.展开更多
Investigations of the growth,interaction,and coalescence of cracks are important because they help to provide tools for the more realistic modeling of rock masses containing low persistence discontinuities and better ...Investigations of the growth,interaction,and coalescence of cracks are important because they help to provide tools for the more realistic modeling of rock masses containing low persistence discontinuities and better estimations of the strength and stiffness of a rock material.Understanding the coalescence mechanism is useful for justifying the mechanism of continental crustal deformation,evaluating the structural failure of slopes with rock bridges,and analyzing the stability of tunnels when a mode I or mix mode failure mechanism is involved.The evaluation of crack growth can provide valuable information about the mechanism for the formation of new geological structures,and the formation,evolution,and growth of faults.This paper reports the results of diametrical compression tests on rocklike disk-shaped specimens.Each specimen contained two pre-existing open or closed flaws.The growth,interaction,and coalescence of the pre-existing flaws were investigated both physically and numerically.A hybrid bonded particle-finite element system was used in the numerical simulation.The results of the physical and numerical studies were in good agreement.In particular,the induced crack patterns showed close agreement in the physical and numerical tests.Digital microscope image processing was used in the physical tests to study the dislocations along the initial flaws.It was shown that wing crack formation was responsible for the failure of the specimen when flaws were inclined with respect to the loading direction.The crack growth and linkage were shown to be affected by the friction between faces of the flaws.In addition,the slip distributions at the flaws surfaces were illustrated and examined to understand the crack propagation mechanism.The effects of the flaws on the disk failure loads were assessed both numerically and experimentally as well.展开更多
基金Funded by the National Key Research and Development Program of China(No.2023YFB260012602)the Shandong Provincial Natural Science Foundation(No.ZR2023ME208)。
文摘To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-shaped flaws are subjected to uniaxial compressive tests under different F-T cycles.Experimental observations show that the uniaxial compressive strength of specimens are significantly influenced by F-T cycles and their failure modes are mainly affected by the central angleαof the prefabricated flaws.Unlike the specimens with a central angle of 60°,the specimens with a central angle of 120°and 180°have greater curvature of flaws,so tensile cracks occur in the arc-top area of their prefabricated flaws.According to experimental images observed by environmental scanning electron microscope(ESEM),as the number of F-T cycles increases,the deterioration effect of the specimen becomes more obvious,which is specifically reflected in the increase of the mass loss,peak stress loss,and damage variables as a power function,and the peak strain decreases as a quadratic polynomial.According to numerical results using two-dimensional particle flow code(PFC2D),it is found that F-T cycles cause more damage to the specimen in the early stages than in the later ones.The area of the concentrated compressive stress zone in the middle is decreased due to the increased number of F-T cycles,while the area of the surrounding tensile-shear stress zone is increased.The models appear different failure modes due to the release of concentrated stress in different tensile-shear zones.
文摘The R F first order second moment method will produce more error for calculating the reliability of welded engineering pipe structures when the failure function is seriously nonlinear and the random variables don′t serve as normal distribution. In order to increase the computing accuracy of reliability, an improved FOSM method is used for calculating the failure probability of welded pipes with flaws in this paper. Because of solving the problems of the linear expansion of failure function at the failure point and constructing equivalent normal variables, the new algorithm can greatly improve the calculating accuracy of probability of the welded pipes with cracks. The examples show that this method is simple, efficient and accurate for reliability safety assessment of the welded pipes with cracks. It can save more time than the Monte Carlo method does, so that the improved FOSM method is recommended for engineering reliability safety assessment of the welded pipes with flaws.
基金Project(2014CB046905,2013CB36003)supported by the National Basic Research Program of ChinaProject(NCET-12-0961)supported by the Program for New Century Excellent Talents in University,China+1 种基金Projects(51179189,41272344)supported by the National Natural Science Foundation of ChinaProject(HBKLCIV201201)supported by the Open Research Fund Program of the Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province,China
文摘Based on the axial stress-axial strain curves,the effect of fissure angle on the strength and deformation behavior of sandstone specimens containing combined flaws is analyzed.The mechanical parameters of sandstone specimens containing combined flaws are all lower than that of intact specimen,but the reduction extent is distinctly related to the fissure angle.The results of sandstone specimens containing combined flaws are obtained by the acoustic emission,which can be used to monitor the crack initiation and propagation.The ultimate failure mode and crack coalescence behavior are evaluated for brittle sandstone specimens containing combined flaws.Nine different crack types are identified on the basis of their geometry and crack coalescence mechanism(tensile crack,hole collapse,far-field crack and surface spalling)for combined flaws.The photographic monitoring was also adopted for uniaxial compression test in order to confirm the sequence of crack coalescence in brittle sandstone specimens containing combined flaws,which recorded the real-time crack coalescence process during entire deformation.According to the monitored results,the effect of crack coalescence process on the strength and deformation behavior is investigated based on a detailed analysis for brittle sandstone specimens containing combined flaws by using digital photogrammetry.
基金supported by the National Natural Science Foundation of China (Grants 41572310, 41272351)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grants XDB10030301, XDB10030304)support provided by the CAS-TWAS Presidential Fellowship, University of Chinese Academy of Sciences, Beijing, China
文摘Failure of rock mass that is subjected to compressive loads occurs from initiation, propagation, and linkage of new cracks from preexisting fissures. Our research investigates the cracking behaviour and coalescence process in a brittle material with two non-parallel overlapping flaws using a high-speed camera. The coalescence tensile crack and tensile wing cracks were the first cracks to occur from the preexisting flaws. The initiation stresses of the primary cracks at the two tips of each flaw were simultaneous and decreased with reduced flaw inclination angle. The following types of coalescence cracks were identified between the flaws: primary tensile coalescence crack, tensile crack linkage, shear crack linkage, mixed tensile-shear crack, and indirect crack coalescence. Coalescence through tensile linkage occurred mostly at pre-peak stress. In contrast, coalescence through shear or mixed tensile-shear cracks occurred at higher stress. Overall, this study indicates that the geometry of preexisting flaws affect crack initiation and coalescence behaviour.
文摘In the October 2014 edition of JAMA, Dr. Hinman and her colleagues published an acupuncture clinical trial entitled Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial＂ and concluded that in patients older than 50 years with moderate or severe chronic knee pain, neither laser nor needle acupuncture conferred benefit over sham for pain or function. Our findings do not support acupuncture for these patients[1].
文摘In the October 2014 publication of JAMA, Dr. Hinman and colleagues published the study “Acupuncture for Chronic Knee Pain： A Randomized Clinical Trial,” which concluded that in patients older than 50 years with moderate or severe chronic knee pain, neither laser nor needle acupuncture conferred benefit over sham for pain or function. Our findings do not support acupuncture for these patients.
文摘CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.
文摘Emma is the heroine of one of the novels written by Jane Austen(1775-1817) who is among the most widely read writers in English literature.In the novel,also named Emma,Austen portrayed Emma as a young,pretty and smart gentlewoman,yet she was not a perfect or flawless character.She dose not seem to have any sense of her own limitations.Her self-conceit and meddling nature are two of her most fatal character flaws.In this article,we will give a detailed analysis of Emma's flaws supported by various incidents as the novel progresses.We will also find out the two major factors that contribute to develop these character flaws,which are the negative effects caused on her by people very close to her and also the society of her time.
文摘In the October 2014 publication of JAMA,Dr.Hinman and colleagues published the study＂Acupuncture for Chronic Knee Pain：A Randomized Clinical Trial,＂in which the authors concluded that＂in patients older than50 years with moderate or severe chronic knee pain,neither laser nor needle acupuncture conferred benefi t over sham for pain or function.Our fi ndings do not support acupuncture[1]
文摘Hamlet is the most discussed of Shakespeare's tragedies, while The Great Gatsby is the masterpiece of Fitzgerald. It is true that the tragic flaws of the protagonists would be a key factor driving the development of the plots. In these two dramas, the flaws of the protagonists leaded to their tragic endings which are related to their own characteristics of the protagonists. And the ends of the stories are with the tragedies.
文摘Digital in the daily life of companies undeniably leads them to use services and applications of all kinds. Companies in their permanent quest for the exchange of information devote themselves to the use of the Internet which nowadays constitutes an open door for the birth of several types of faults, some of which are unknown to certain digital professionals in the field. Corporate. The purpose of this research is to show the probable existence of digital security flaws in the daily activities carried out by companies in Burkina Faso. In companies in Burkina Faso, we seem to see a way of working that does not respect the standards and safety standards prescribed by ISO 27001. We seem to see a way of working based on the result of the gain and not on the securities measures and integrity of critical data, data confidentiality, management and prevention of possible security risks related to their activities. We seem to be witnessing in companies the immanent presence of faults which could be the work of the users of the system, of the infrastructure used which is outdated or badly configured, of software anomalies linked to programming errors, and to poor implementation of the security policy within the companies. This research is important because it exposes the handicaps that companies have in terms of digital security. The expected result is to bring out existing flaws that are not taken seriously by IT staff and propose possible solutions to overcome these security risks.
文摘The Spanish Tragedy, written by Thomas Kyd in the late 1580 s, was the grandfather of all revenge tragedies. It established a new genre named revenge tragedy in English theater. Its well-developed characters, timeless themes, dramatic intrigue and pioneering adoption of blank verse enabled it to be viewed as a classic of London theater. Yet it also has received criticisms over the past centuries. Based on Aristotle's opinion of a perfect tragedy in"Poetics", this paper aims to point out the flaws of the play from five perspectives: the fate of Hieronimo, the cause of it, Bel-imperia's sudden love for Horatio, subplot concerning Villuppo and Alexandro, the discovery and the diction.
文摘In the mid-1980’s researchers at Cleveland State University made a startling discovery. They conducted an experiment by creating two fictitious job candidates—David and John.Thecandidates had identical resumes and letters of reference.The only difference was that John’s letterincluded the sentence“Sometimes,John can be difficult to get along with.”They showed the re-
基金Funded by the Program for New Century Excellent Talents in University (11-0687)the National Natural Science Foundation of China (51172169)the Fundamental Research Funds for the Central Universities (Wuhan University of Technology)
文摘We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consistent with the original one. This study is very helpful to further enhance the infrared glass flaw inspection technique.
基金supported by China Scholarship Council,Tianjin Science and Technology Committee(No.12JCZDJC20800)Science and Technology Planning Project of Tianjin(No.13ZCZDGX01098)+2 种基金NSF TRUST(The Team for Research in Ubiquitous Secure Technology)Science and Technology Center(No.CCF-0424422)National High Technology Research and Development Program of Chia(863Program)(No.2013BAH01B05)National Natural Science Foundation of China(No.61402264)
文摘Logic flaws within web applications will allow malicious operations to be triggered towards back-end database. Existing approaches to identifying logic flaws of database accesses are strongly tied to structured query language （SQL） statement construction and cannot be applied to the new generation of web applications that use not only structured query language （NoSQL） databases as the storage tier. In this paper, we present Lom, a black-box approach for discovering many categories of logic flaws within MongoDB- based web applications. Our approach introduces a MongoDB operation model to support new features of MongoDB and models the application logic as a mealy finite state machine. During the testing phase, test inputs which emulate state violation attacks are constructed for identifying logic flaws at each application state. We apply Lom to several MongoDB-based web applications and demonstrate its effectiveness.
基金substantially supported by the National Program on Major Research Project (no.2016YFC0701301-02)Jiangsu Higher Education Institutions for the Priority Academic Development Program (CE021-34)
文摘To give an insight into the understanding of damage evolution and crack propagation in rocks,a series of uniaxial and biaxial compression numerical tests are carried out.The investigations show that damage evolution occurs firstly in the weak rock,the area around the flaw and the area between the flaw and the neighboring rock layer.Cracks mostly generate as tensile cracks under uniaxial compression and shear cracks under biaxial compression.Crack patterns are classified and divided.The relationship between the accumulated lateral displacement and the short radius（b）is fitted,and the equation of crack path is also established.
基金the Innovation Program of ShanghaiMunicipal Education Commission(No.09YZ340)the Leading Academic Discipline Project of ShanghaiMunicipal Education Commission(No.J51301)+2 种基金the Special Scientific Research Project of Scienceand Technology Commission of Shanghai Municipality(No.08240512000)the Shanghai Municipal EducationCommission Scientific Foundation Projection(No.06LZ009)the Shanghai Key Science and TechnologyProject(No.061612041)
文摘In this paper,a modified genetic local search algorithm(MGLSA) is proposed.The proposed algorithm is resulted from employing the simulated annealing technique to regulate the variance of the Gaussian mutation of the genetic local search algorithm(GLSA).Then,an MGLSA-based inverse algorithm is proposed for magnetic flux leakage(MFL) signal inversion of corrosive flaws,in which the MGLSA is used to solve the optimization problem in the MFL inverse problem.Experimental results demonstrate that the MGLSA-based inverse algorithm is more robust than GLSA-based inverse algorithm in the presence of noise in the measured MFL signals.
文摘This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accompanying Test (EAT) algorithm in this paper. Two propositions in algebraic topology are presented, which are the foundation of the EAT algorithm. As the modeling is the first step for rendering in the animation and visualization, or computer-aided design (CAD) in related applications, the flaws can bring some serious problems in the final image or product, such as an artificial sense in animation rendering or a mistaken product in industry. To verify the EAT progressive procedure, a three-dimensional (3D) stamp model is constructed. The modeling process is accompanied by the EAT procedure. The EAT scheme is verified as the flaws in the stamp model are found and modified.
基金funded by the National Natural Science Foundation of China(Grant No.52109152)the Jiangxi Provincial Natural Science Foundation(Grant Nos.20242BAB25023 and 20232BAB214086).
文摘Structural internal flaws often weaken the performance and integral stability,while traditional nondestructive testing or inversion methods face challenges of high cost and low efficiency in quantitative flaw identification.To quickly identify internal flaws within structures,a deep learning model for flaw detection is proposed based on the image quadtree scaled boundary finite element method(SBFEM)combined with a deep neural network(DNN).The training dataset is generated fromthe numerical simulations using the balanced quadtree algorithmand SBFEM,where the structural domain is discretized based on recursive decomposition principles andmesh refinement is automatically performed in the flaw boundary regions.The model contains only six types of elements and hanging nodes don’t affect the solution accuracy,resulting in a high degree of automation and significantly reducing the cost of the training dataset.The deep artificial neural network for flaw detection is constructed using DNN as the learning framework,effectively mitigating the risk of the objective function converging to local optima during training.Statistical methods are employed to evaluate the accuracy of the inversionmodel,and the influences of flaw size and the number of training samples on the performance are examined.In statistical results of single flaw,the 95%confidence intervals of the relative error for(x,y,r)are[2.16%,2.76%],[1.53%,1.96%]and[1.49%,1.91%],respectively.The 95%confidence interval of the comprehensive relative error for double flaws is[3.06%,3.62%].The results demonstrate that the predicted flaw parameters align closely with the reserved clean data,indicating that themodel can accurately quantify both the location and size of structural flaws.
文摘Investigations of the growth,interaction,and coalescence of cracks are important because they help to provide tools for the more realistic modeling of rock masses containing low persistence discontinuities and better estimations of the strength and stiffness of a rock material.Understanding the coalescence mechanism is useful for justifying the mechanism of continental crustal deformation,evaluating the structural failure of slopes with rock bridges,and analyzing the stability of tunnels when a mode I or mix mode failure mechanism is involved.The evaluation of crack growth can provide valuable information about the mechanism for the formation of new geological structures,and the formation,evolution,and growth of faults.This paper reports the results of diametrical compression tests on rocklike disk-shaped specimens.Each specimen contained two pre-existing open or closed flaws.The growth,interaction,and coalescence of the pre-existing flaws were investigated both physically and numerically.A hybrid bonded particle-finite element system was used in the numerical simulation.The results of the physical and numerical studies were in good agreement.In particular,the induced crack patterns showed close agreement in the physical and numerical tests.Digital microscope image processing was used in the physical tests to study the dislocations along the initial flaws.It was shown that wing crack formation was responsible for the failure of the specimen when flaws were inclined with respect to the loading direction.The crack growth and linkage were shown to be affected by the friction between faces of the flaws.In addition,the slip distributions at the flaws surfaces were illustrated and examined to understand the crack propagation mechanism.The effects of the flaws on the disk failure loads were assessed both numerically and experimentally as well.
