Advanced driver-assistance systems such as Honda’s collision mitigation brake system(CMBS)can help achieve traffic safety.In this paper,the naturalistic driving study and a series of simulations are combined to bette...Advanced driver-assistance systems such as Honda’s collision mitigation brake system(CMBS)can help achieve traffic safety.In this paper,the naturalistic driving study and a series of simulations are combined to better evaluate the performance of the CMBS in the Chinese traffic environment.First,because safety-critical situations can be diverse especially in the Chinese environment,the Chinese traffic-accident characteristics are analyzed according to accident statistics over the past 17 years.Next,10 Chinese traffic-accident scenarios accounting for more than 80%of traffic accidents are selected.For each typical scenario,353 representative cases are collected from the traffic-management department of Beijing.These real-world accident cases are then reconstructed by the traffic-accident-reconstruction software PC-Crash on the basis of accident-scene diagrams.This study also proposes a systematic analytical process for estimating the effectiveness of the technology using the co-simulation platform of PC-Crash and rateEFFECT,in which 176 simulations are analyzed in detail to assess the accident-avoidance performance of the CMBS.The overall collision-avoidance effectiveness reaches 82.4%,showing that the proposed approach is efficient for avoiding collisions,thereby enhancing traffic safety and improving traffic management.展开更多
A new scheme to verifiably redistribute a secret from the old to new shareholders without reconstruction of the secret is presented in this paper. The scheme allows redistribution between different access structures a...A new scheme to verifiably redistribute a secret from the old to new shareholders without reconstruction of the secret is presented in this paper. The scheme allows redistribution between different access structures and between different threshold schemes. A point worth mentioning is that this verifiable secret redistribution (VSR) scheme can identify dishonest old shareholders during redistribution without any assumption. A certain technique is adopted to verify the correctness of the old shares of the secret. As a result, the scheme is very efficient. It can be applied to proactive secret sharing (PSS) schemes to construct more flexible and practical proactive secret sharing schemes.展开更多
AIM: To determine the rates of success and complications of precut biliary sphincterotomy (PBS) based on prior experience and to compare the complication rates between PBS and standard endoscopic sphincterotomy (E...AIM: To determine the rates of success and complications of precut biliary sphincterotomy (PBS) based on prior experience and to compare the complication rates between PBS and standard endoscopic sphincterotomy (ES). METHODS: A retrospective evaluation of prospectively collected non-randomized data at an academic tertiary referral center, The study included all patients in an eight-year period who underwent PBS and ES by a single endoscopist who had no formal training in PBS. The main outcorne measures of the study were success and complications of PBS with a comparison to complications of ES.RESULTS: A total of 2939 endoscopic retrograde chola ngiopancreatographies (ERCPs) were performed during the study period, including 818 (28%) ES and 150 (5%) PBS procedures. Selective biliary cannulation via PBS was successful at the first attempt in 75% of the patients. Cannulation was achieved in an additional 13% of the patients at a subsequent attempt (total 87%). Complication rate from PBS was 45% higher than ES, but did not differ significantly [7% (10/50) vs 5% (38/818), P = 0.29]. None of the complications from PBS was severe. A significant trend towards increasing success existed with regard to the endoscopist's first attempt at precut (P = 0.0393, Cochran-Armitage exact test for trend, Z = -1.7588). CONCLUSION: Despite the lack of specific training in this technique, PBS was performed with a high success rate and a complication rate similar to or less than reports from other experienced centers. These results suggest that endoscopic experience and perhaps innate endoscopic skill may play an important role in the outcome of this procedure.展开更多
Attribute revocation is inevitable and al- so important for Attribute-Based Encryption (ABE) in practice. However, little attention has been paid to this issue, and it retrains one of the rmin obsta-cles for the app...Attribute revocation is inevitable and al- so important for Attribute-Based Encryption (ABE) in practice. However, little attention has been paid to this issue, and it retrains one of the rmin obsta-cles for the application of ABE. Most of existing ABE schemes support attribute revocation work under indirect revocation model such that all the users' private keys will be affected when the revo-cation events occur. Though some ABE schemes have realized revocation under direct revocation model such that the revocation list is embedded in the ciphertext and none of the users' private keys will be affected by revocation, they mostly focused on the user revocation that revokes the user's whole attributes, or they can only be proven to be selectively secure. In this paper, we first define a model of adaptively secure ABE supporting the at- tribute revocation under direct revocation model. Then we propose a Key-Policy ABE (KP-ABE) scheme and a Ciphertext-Policy ABE (CP-ABE) scheme on composite order bilinear groups. Finally, we prove our schemes to be adaptively secure by employing the methodology of dual system eno cryption.展开更多
Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and soft...Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and software resources sufficiently,but also bring a series of security,reliability and credibility problems.To solve these problems,a novel secure-agent-based trustworthy virtual private cloud model named SATVPC was proposed for the integrated and open cloud computing environment.Through the introduction of secure-agent technology,SATVPC provides an independent,safe and trustworthy computing virtual private platform for multi-tenant systems.In order to meet the needs of the credibility of SATVPC and mandate the trust relationship between each task execution agent and task executor node suitable for their security policies,a new dynamic composite credibility evaluation mechanism was presented,including the credit index computing algorithm and the credibility differentiation strategy.The experimental system shows that SATVPC and the credibility evaluation mechanism can ensure the security of open computing environments with feasibility.Experimental results and performance analysis also show that the credit indexes computing algorithm can evaluate the credibilities of task execution agents and task executor nodes quantitatively,correctly and operationally.展开更多
Privacy-preserving data publishing (PPDP) is one of the hot issues in the field of the network security. The existing PPDP technique cannot deal with generality attacks, which explicitly contain the sensitivity atta...Privacy-preserving data publishing (PPDP) is one of the hot issues in the field of the network security. The existing PPDP technique cannot deal with generality attacks, which explicitly contain the sensitivity attack and the similarity attack. This paper proposes a novel model, (w,γ, k)-anonymity, to avoid generality attacks on both cases of numeric and categorical attributes. We show that the optimal (w, γ, k)-anonymity problem is NP-hard and conduct the Top-down Local recoding (TDL) algorithm to implement the model. Our experiments validate the improvement of our model with real data.展开更多
Objective To explore the safety and efficacy of frameless stereotactic brain biopsy.Methods Diagnostic accuracy was calculated by comparing biopsy diagnosis with definitive pathology in 62 patients who underwent frame...Objective To explore the safety and efficacy of frameless stereotactic brain biopsy.Methods Diagnostic accuracy was calculated by comparing biopsy diagnosis with definitive pathology in 62 patients who underwent frameless stereotactic brain biopsy between January 2008 and December 2010 in Xiamen University Southeast Hospital.Preoperative characteristics and histological diagnosis were reviewed and then information was analysed to identify factors associated with the biopsy not yielding a diagnosis and complications.Results Diagnostic yield was 93.5%.No differences were found between pathological diagnosis and frozen pathological diagnosis.The most common lesions were astrocytic lesions,included 16 cases of low-grade glioma and 12 cases of malignant glioma.Remote hemorrhage,metastasis,and lymphoma were following in incidence.Multiple brain lesions were found in 17 cases (27.4%).Eleven cases were frontal lesions (17.7%),8 were frontotemporal (12.9%),6 were frontoparietal (9.7%),and 5 each were temporal,parietal,and parietotemporal lesions (8.1%).Postoperative complications occurred in 21.0% of the patients after biopsies,including 10 haemorrhages (16.1%) and 3 temporary neurological deficits (1 epilepsy,1 headache,and 1 partial hemiparesis).No patient required operation for hematoma evacuation.Conclusion Frameless stereotactic biopsy is an effective and safe technique for histologic diagnosis of brain lesions,particularly for multifocal and frontal lesions.展开更多
The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economi...The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economic advantages.Over the past decades,China has gained successful experience in the construction of 200 m CFRDs,providing the necessary technical accumulation for the development of 250–300 m ultra-high CFRDs.This paper summarizes these successful experiences and analyzes the problems of a number of major 200 m CFRDs around the world.In addition,it discusses the key technologies and latest research progress regarding safety in the construction of 250–300 m ultra-high CFRDs,and suggests focuses and general ideas for future research.展开更多
In Heterogeneous Wireless Sensor Networks, the mobility of the sensor nodes becomes essential in various applications. During node mobility, there are possibilities for the malicious node to become the cluster head or...In Heterogeneous Wireless Sensor Networks, the mobility of the sensor nodes becomes essential in various applications. During node mobility, there are possibilities for the malicious node to become the cluster head or cluster member. This causes the cluster or the whole network to be controlled by the malicious nodes. To offer high level of security, the mobile sensor nodes need to be authenticated. Further, clustering of nodes improves scalability, energy efficient routing and data delivery. In this paper, we propose a cluster based secure dynamic keying technique to authenticate the nodes during mobility. The nodes with high configuration are chosen as cluster heads based on the weight value which is estimated using parameters such as the node degree, average distance, node's average speed, and virtual battery power. The keys are dynamically generated and used for providing security. Even the keys are compromised by the attackers, they are not able to use the previous keys to cheat or disuse the authenticated nodes. In addition, a bidirectional malicious node detection technique is employed which eliminates the malicious node from the network. By simulation, it is proved that the proposed technique provides efficient security with reduced energy consumption during node mobility.展开更多
Utilized fundamental theory and analysis method of Incomplete Information repeated games, introduced Incomplete Information into repeated games, and established two stages dynamic games model of the local authority an...Utilized fundamental theory and analysis method of Incomplete Information repeated games, introduced Incomplete Information into repeated games, and established two stages dynamic games model of the local authority and the coal mine owner. The analytic result indicates that: so long as the country established the corresponding rewards and punishments incentive mechanism to the local authority departments responsible for the work, it reports the safety accident in the coal mine on time. The conclusion that the local government displays right and wrong cooperation behavior will be changed with the introduction of the Incomplete Information. Only has the local authority fulfill their responsibility, can the unsafe accident be controlled effectively. Once this kind of cooperation of local government appears, the costs of the country on the safe supervise and the difficulty will be able to decrease greatly.展开更多
This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a nu...This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.展开更多
The ongoing need to deliver improved safety, productivity and environmental benefit in coal mining presents an open challenge as well as a powerful incentive to develop new and improved solutions. This paper assesses ...The ongoing need to deliver improved safety, productivity and environmental benefit in coal mining presents an open challenge as well as a powerful incentive to develop new and improved solutions. This paper assesses the critical role that enabling technologies have played in the delivery of remote and automated capability for longwall mining. A brief historical account is given to highlight key technical contributions which have influenced the direction and development of present-day longwall technology. The current state of longwall automation is discussed with particular attention drawn to the technologies that enable automated capability. Outcomes are presented from an independently conducted case study that assessed the impact that CSIRO's LASC longwall automation research has made to the longwall mining industry in Australia. Importantly, this study reveals how uptake of this innova- tive technology has significantly benefitted coal mine productivity, improved working conditions for personnel and enhanced environmental outcomes. These benefits have been widely adopted with CSIRO automation technology being used in 60 per cent of all Australian underground operations. International deployment of the technology is also emerging. The paper concludes with future challenges and opportunities to highfight the ongoing scope for longwall automation research and development.展开更多
The security of critical data is an important issue for distributed storage system design,especially for long-term storage.ESSA (An Efficient and Secure Splitting Algorithm for Distributed Storage Systems) is presente...The security of critical data is an important issue for distributed storage system design,especially for long-term storage.ESSA (An Efficient and Secure Splitting Algorithm for Distributed Storage Systems) is presented,which takes advantage of a two level information dispersal scheme to strengthen the security of data.In ESSA,the approach of knight’s tour problem,which is NP-Complete,is introduced to scramble data at the first level,and a split cube is used to split scrambled data at the second level.Thus,it is very difficult for the malicious user to get information because the task of reconstructing the original data needs more computation than they can tolerate.We prove that the security of ESSA is better than encryption algorithm and not inferior to erasure codes and secret sharing.Experimental results show that distributed storage systems exploiting ESSA has greater efficiency than that exploiting keyed encryption,erasure codes and secret sharing.展开更多
Objective To evaluate the effectiveness and safety of a computer-controlled periodontal ligament (PDL) injection system to the local soft tissues as the primary technique in endodontic access to mandibular posteri...Objective To evaluate the effectiveness and safety of a computer-controlled periodontal ligament (PDL) injection system to the local soft tissues as the primary technique in endodontic access to mandibular posterior teeth in patients with irreversible pulpitis. Methods A total of 162 Chinese patients who had been diagnosed with irreversible pulpitis in their mandibular posterior teeth without acute infection or inflammation in the periodontal tissues were enrolled in this clinical study. The patients were divided into 3 groups according to the position of the involved tooth: the premolar group (PM, z2=38), first molar group (FM, n=66), and second molar group (SM, n=58). All the patients received computer-controlled PDL injection with 4% articaine and 1 ' 100 000 epinephrine. Immediately after the injection, endodontic access was performed, and the degree of pain during the treatment was evaluated by the patients using Visual Analogue Scale for pain. The success rates were compared among the 3 groups. The responses of local soft tissues were evaluated 3-8 days and 3 weeks after the procedure. Results The overall success rate was 76.5%. There was a significant difference in success rates among the PM, FM, and SM groups (92.1%, 53.0%, 93.1%, respectively; 2 X =34.3, P〈0.01). Both the PM and SM groups showed higher success rates than that of the FM group (v=l, f=16.73, P〈0.01, v=l, Z = 4.5, X2 2 P〈0.01). No irreversible adverse effects on the periodontal soft tissues at the injection sites were observed in the follow-up visits in any of the groups. Conclusion The computer-controlled PDL injection system demonstrates both satisfactory anesthetic effects and safety in local soft tissues as primary anesthetic technique in endodontic access to the mandibular posterior teeth in patients with irreversible pulpitis.展开更多
基金Project(51625503) supported by the National Science Fund for Distinguished Young Scholars,ChinaProject(61790561) supported by the National Natural Science Foundation of China+1 种基金Project(20163000124) supported by Tsinghua-Honda Joint Research,ChinaProject(TTS2017-02) supported by the Open Fund for Jiangsu Key Laboratory of Traffic and Transportation Security,China
文摘Advanced driver-assistance systems such as Honda’s collision mitigation brake system(CMBS)can help achieve traffic safety.In this paper,the naturalistic driving study and a series of simulations are combined to better evaluate the performance of the CMBS in the Chinese traffic environment.First,because safety-critical situations can be diverse especially in the Chinese environment,the Chinese traffic-accident characteristics are analyzed according to accident statistics over the past 17 years.Next,10 Chinese traffic-accident scenarios accounting for more than 80%of traffic accidents are selected.For each typical scenario,353 representative cases are collected from the traffic-management department of Beijing.These real-world accident cases are then reconstructed by the traffic-accident-reconstruction software PC-Crash on the basis of accident-scene diagrams.This study also proposes a systematic analytical process for estimating the effectiveness of the technology using the co-simulation platform of PC-Crash and rateEFFECT,in which 176 simulations are analyzed in detail to assess the accident-avoidance performance of the CMBS.The overall collision-avoidance effectiveness reaches 82.4%,showing that the proposed approach is efficient for avoiding collisions,thereby enhancing traffic safety and improving traffic management.
文摘A new scheme to verifiably redistribute a secret from the old to new shareholders without reconstruction of the secret is presented in this paper. The scheme allows redistribution between different access structures and between different threshold schemes. A point worth mentioning is that this verifiable secret redistribution (VSR) scheme can identify dishonest old shareholders during redistribution without any assumption. A certain technique is adopted to verify the correctness of the old shares of the secret. As a result, the scheme is very efficient. It can be applied to proactive secret sharing (PSS) schemes to construct more flexible and practical proactive secret sharing schemes.
文摘AIM: To determine the rates of success and complications of precut biliary sphincterotomy (PBS) based on prior experience and to compare the complication rates between PBS and standard endoscopic sphincterotomy (ES). METHODS: A retrospective evaluation of prospectively collected non-randomized data at an academic tertiary referral center, The study included all patients in an eight-year period who underwent PBS and ES by a single endoscopist who had no formal training in PBS. The main outcorne measures of the study were success and complications of PBS with a comparison to complications of ES.RESULTS: A total of 2939 endoscopic retrograde chola ngiopancreatographies (ERCPs) were performed during the study period, including 818 (28%) ES and 150 (5%) PBS procedures. Selective biliary cannulation via PBS was successful at the first attempt in 75% of the patients. Cannulation was achieved in an additional 13% of the patients at a subsequent attempt (total 87%). Complication rate from PBS was 45% higher than ES, but did not differ significantly [7% (10/50) vs 5% (38/818), P = 0.29]. None of the complications from PBS was severe. A significant trend towards increasing success existed with regard to the endoscopist's first attempt at precut (P = 0.0393, Cochran-Armitage exact test for trend, Z = -1.7588). CONCLUSION: Despite the lack of specific training in this technique, PBS was performed with a high success rate and a complication rate similar to or less than reports from other experienced centers. These results suggest that endoscopic experience and perhaps innate endoscopic skill may play an important role in the outcome of this procedure.
文摘Attribute revocation is inevitable and al- so important for Attribute-Based Encryption (ABE) in practice. However, little attention has been paid to this issue, and it retrains one of the rmin obsta-cles for the application of ABE. Most of existing ABE schemes support attribute revocation work under indirect revocation model such that all the users' private keys will be affected when the revo-cation events occur. Though some ABE schemes have realized revocation under direct revocation model such that the revocation list is embedded in the ciphertext and none of the users' private keys will be affected by revocation, they mostly focused on the user revocation that revokes the user's whole attributes, or they can only be proven to be selectively secure. In this paper, we first define a model of adaptively secure ABE supporting the at- tribute revocation under direct revocation model. Then we propose a Key-Policy ABE (KP-ABE) scheme and a Ciphertext-Policy ABE (CP-ABE) scheme on composite order bilinear groups. Finally, we prove our schemes to be adaptively secure by employing the methodology of dual system eno cryption.
基金Projects(61202004,61272084)supported by the National Natural Science Foundation of ChinaProjects(2011M500095,2012T50514)supported by the China Postdoctoral Science Foundation+2 种基金Projects(BK2011754,BK2009426)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(12KJB520007)supported by the Natural Science Fund of Higher Education of Jiangsu Province,ChinaProject(yx002001)supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and software resources sufficiently,but also bring a series of security,reliability and credibility problems.To solve these problems,a novel secure-agent-based trustworthy virtual private cloud model named SATVPC was proposed for the integrated and open cloud computing environment.Through the introduction of secure-agent technology,SATVPC provides an independent,safe and trustworthy computing virtual private platform for multi-tenant systems.In order to meet the needs of the credibility of SATVPC and mandate the trust relationship between each task execution agent and task executor node suitable for their security policies,a new dynamic composite credibility evaluation mechanism was presented,including the credit index computing algorithm and the credibility differentiation strategy.The experimental system shows that SATVPC and the credibility evaluation mechanism can ensure the security of open computing environments with feasibility.Experimental results and performance analysis also show that the credit indexes computing algorithm can evaluate the credibilities of task execution agents and task executor nodes quantitatively,correctly and operationally.
基金supported in part by Research Fund for the Doctoral Program of Higher Education of China(No.20120009110007)Program for Innovative Research Team in University of Ministry of Education of China (No.IRT201206)+3 种基金Program for New Century Excellent Talents in University(NCET-110565)the Fundamental Research Funds for the Central Universities(No.2012JBZ010)the Open Project Program of Beijing Key Laboratory of Trusted Computing at Beijing University of TechnologyBeijing Higher Education Young Elite Teacher Project(No. YETP0542)
文摘Privacy-preserving data publishing (PPDP) is one of the hot issues in the field of the network security. The existing PPDP technique cannot deal with generality attacks, which explicitly contain the sensitivity attack and the similarity attack. This paper proposes a novel model, (w,γ, k)-anonymity, to avoid generality attacks on both cases of numeric and categorical attributes. We show that the optimal (w, γ, k)-anonymity problem is NP-hard and conduct the Top-down Local recoding (TDL) algorithm to implement the model. Our experiments validate the improvement of our model with real data.
文摘Objective To explore the safety and efficacy of frameless stereotactic brain biopsy.Methods Diagnostic accuracy was calculated by comparing biopsy diagnosis with definitive pathology in 62 patients who underwent frameless stereotactic brain biopsy between January 2008 and December 2010 in Xiamen University Southeast Hospital.Preoperative characteristics and histological diagnosis were reviewed and then information was analysed to identify factors associated with the biopsy not yielding a diagnosis and complications.Results Diagnostic yield was 93.5%.No differences were found between pathological diagnosis and frozen pathological diagnosis.The most common lesions were astrocytic lesions,included 16 cases of low-grade glioma and 12 cases of malignant glioma.Remote hemorrhage,metastasis,and lymphoma were following in incidence.Multiple brain lesions were found in 17 cases (27.4%).Eleven cases were frontal lesions (17.7%),8 were frontotemporal (12.9%),6 were frontoparietal (9.7%),and 5 each were temporal,parietal,and parietotemporal lesions (8.1%).Postoperative complications occurred in 21.0% of the patients after biopsies,including 10 haemorrhages (16.1%) and 3 temporary neurological deficits (1 epilepsy,1 headache,and 1 partial hemiparesis).No patient required operation for hematoma evacuation.Conclusion Frameless stereotactic biopsy is an effective and safe technique for histologic diagnosis of brain lesions,particularly for multifocal and frontal lesions.
文摘The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economic advantages.Over the past decades,China has gained successful experience in the construction of 200 m CFRDs,providing the necessary technical accumulation for the development of 250–300 m ultra-high CFRDs.This paper summarizes these successful experiences and analyzes the problems of a number of major 200 m CFRDs around the world.In addition,it discusses the key technologies and latest research progress regarding safety in the construction of 250–300 m ultra-high CFRDs,and suggests focuses and general ideas for future research.
文摘In Heterogeneous Wireless Sensor Networks, the mobility of the sensor nodes becomes essential in various applications. During node mobility, there are possibilities for the malicious node to become the cluster head or cluster member. This causes the cluster or the whole network to be controlled by the malicious nodes. To offer high level of security, the mobile sensor nodes need to be authenticated. Further, clustering of nodes improves scalability, energy efficient routing and data delivery. In this paper, we propose a cluster based secure dynamic keying technique to authenticate the nodes during mobility. The nodes with high configuration are chosen as cluster heads based on the weight value which is estimated using parameters such as the node degree, average distance, node's average speed, and virtual battery power. The keys are dynamically generated and used for providing security. Even the keys are compromised by the attackers, they are not able to use the previous keys to cheat or disuse the authenticated nodes. In addition, a bidirectional malicious node detection technique is employed which eliminates the malicious node from the network. By simulation, it is proved that the proposed technique provides efficient security with reduced energy consumption during node mobility.
文摘Utilized fundamental theory and analysis method of Incomplete Information repeated games, introduced Incomplete Information into repeated games, and established two stages dynamic games model of the local authority and the coal mine owner. The analytic result indicates that: so long as the country established the corresponding rewards and punishments incentive mechanism to the local authority departments responsible for the work, it reports the safety accident in the coal mine on time. The conclusion that the local government displays right and wrong cooperation behavior will be changed with the introduction of the Incomplete Information. Only has the local authority fulfill their responsibility, can the unsafe accident be controlled effectively. Once this kind of cooperation of local government appears, the costs of the country on the safe supervise and the difficulty will be able to decrease greatly.
基金the National Basic Research Program of China(No. 2006CB303104)the City University of Hong Kong under theSRG Project, China (No. 7002134)
文摘This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.
文摘The ongoing need to deliver improved safety, productivity and environmental benefit in coal mining presents an open challenge as well as a powerful incentive to develop new and improved solutions. This paper assesses the critical role that enabling technologies have played in the delivery of remote and automated capability for longwall mining. A brief historical account is given to highlight key technical contributions which have influenced the direction and development of present-day longwall technology. The current state of longwall automation is discussed with particular attention drawn to the technologies that enable automated capability. Outcomes are presented from an independently conducted case study that assessed the impact that CSIRO's LASC longwall automation research has made to the longwall mining industry in Australia. Importantly, this study reveals how uptake of this innova- tive technology has significantly benefitted coal mine productivity, improved working conditions for personnel and enhanced environmental outcomes. These benefits have been widely adopted with CSIRO automation technology being used in 60 per cent of all Australian underground operations. International deployment of the technology is also emerging. The paper concludes with future challenges and opportunities to highfight the ongoing scope for longwall automation research and development.
基金This study is supported by National Natural Science Foundation of China (No.60973146) National Natur al Science Foundation of Beijing (No.4092029) The Fundamental Research Funds for the Central Universities (No.2009RC0217). We also thank the anonymous reviewers for their constructive comments.
文摘The security of critical data is an important issue for distributed storage system design,especially for long-term storage.ESSA (An Efficient and Secure Splitting Algorithm for Distributed Storage Systems) is presented,which takes advantage of a two level information dispersal scheme to strengthen the security of data.In ESSA,the approach of knight’s tour problem,which is NP-Complete,is introduced to scramble data at the first level,and a split cube is used to split scrambled data at the second level.Thus,it is very difficult for the malicious user to get information because the task of reconstructing the original data needs more computation than they can tolerate.We prove that the security of ESSA is better than encryption algorithm and not inferior to erasure codes and secret sharing.Experimental results show that distributed storage systems exploiting ESSA has greater efficiency than that exploiting keyed encryption,erasure codes and secret sharing.
文摘Objective To evaluate the effectiveness and safety of a computer-controlled periodontal ligament (PDL) injection system to the local soft tissues as the primary technique in endodontic access to mandibular posterior teeth in patients with irreversible pulpitis. Methods A total of 162 Chinese patients who had been diagnosed with irreversible pulpitis in their mandibular posterior teeth without acute infection or inflammation in the periodontal tissues were enrolled in this clinical study. The patients were divided into 3 groups according to the position of the involved tooth: the premolar group (PM, z2=38), first molar group (FM, n=66), and second molar group (SM, n=58). All the patients received computer-controlled PDL injection with 4% articaine and 1 ' 100 000 epinephrine. Immediately after the injection, endodontic access was performed, and the degree of pain during the treatment was evaluated by the patients using Visual Analogue Scale for pain. The success rates were compared among the 3 groups. The responses of local soft tissues were evaluated 3-8 days and 3 weeks after the procedure. Results The overall success rate was 76.5%. There was a significant difference in success rates among the PM, FM, and SM groups (92.1%, 53.0%, 93.1%, respectively; 2 X =34.3, P〈0.01). Both the PM and SM groups showed higher success rates than that of the FM group (v=l, f=16.73, P〈0.01, v=l, Z = 4.5, X2 2 P〈0.01). No irreversible adverse effects on the periodontal soft tissues at the injection sites were observed in the follow-up visits in any of the groups. Conclusion The computer-controlled PDL injection system demonstrates both satisfactory anesthetic effects and safety in local soft tissues as primary anesthetic technique in endodontic access to the mandibular posterior teeth in patients with irreversible pulpitis.