Hadoop technology is followed by some security issues. At its beginnings, developers paid attention to the development of basic functionalities mostly, and proposal of security components was not of prime interest. Be...Hadoop technology is followed by some security issues. At its beginnings, developers paid attention to the development of basic functionalities mostly, and proposal of security components was not of prime interest. Because of that, the technology remained vulnerable to malicious activities of unauthorized users whose purpose is to endanger system functionalities or to compromise private user data. Researchers and developers are continuously trying to solve these issues by upgrading Hadoop’s security mechanisms and preventing undesirable malicious activities. In this paper, the most common HDFS security problems and a review of unauthorized access issues are presented. First, Hadoop mechanism and its main components are described as the introduction part of the leading research problem. Then, HDFS architecture is given, and all including components and functionalities are introduced. Further, all possible types of users are listed with an accent on unauthorized users, which are of great importance for the paper. One part of the research is dedicated to the consideration of Hadoop security levels, environment and user assessments. The review also includes an explanation of Log Monitoring and Audit features, and detail consideration of authorization and authentication issues. Possible consequences of unauthorized access to a system are covered, and a few recommendations for solving problems of unauthorized access are offered. Honeypot nodes, security mechanisms for collecting valuable information about malicious parties, are presented in the last part of the paper. Finally, the idea for developing a new type of Intrusion Detector, which will be based on using an artificial neural network, is presented. The detector will be an integral part of a new kind of virtual honeypot mechanism and represents the initial base for future scientific work of authors.展开更多
The act of unauthorized siting of buildings has persisted in most developing countries. Despite numerous efforts at local levels to address this problem, its existence and effects keep on rising in various metropolise...The act of unauthorized siting of buildings has persisted in most developing countries. Despite numerous efforts at local levels to address this problem, its existence and effects keep on rising in various metropolises in Ghana. This research explores the causes of unauthorized siting of buildings in Asakae, a suburb of the Sekondi-Takoradi Metropolis, and suggests measures to curb them. In view of this, a sample size of 182 house-owners was chosen for the study. Accordingly, the sample size was determined using Fisher et al. formula and questionnaire survey approach was adopted for the study. More so, data generated from the survey were further analyzed, using Relative Importance Index. The findings of the survey indicated that ignorance on planning and building regulations, inadequate housing schemes, unrealistic zonings and the location of land are critical variables which influence unauthorized siting of buildings. It is recommended that the populace should be given regular public education on land-use planning and the building regulations of Ghana. More so, the Assemblies should automate their systems, with respect to monitoring and detection of buildings under construction;so that buildings that were being located at unapproved places could be quickly detected, and appropriate measures could be taken before their completion.展开更多
To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put...To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put forward to calculate the uncertainty of the system' s determinations on the irregular access behaviors.Secondly,based on the security entropy,security theorems of hybrid cloud are defined.Finally,typical access control models are analyzed by the method,the method's practicability is validated,and security and applicability of these models are compared.Simulation results prove that the proposed method is suitable for the security quantitative analysis of the access control model and evaluation to access control capability in hybrid cloud.展开更多
Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies ena...Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies enables more dynamic management of data center networks.Although the SDN controller architecture is increasingly optimized for swift policy updates,the data plane,especially the prevailing ternary content-addressable memory(TCAM)based flow tables on physical SDN switches,remains unoptimized for fast rule updates,and is gradually becoming the primary bottleneck along the policy update pipeline.In this paper,we present RuleTris,the first SDN update optimization framework that minimizes rule update latency for TCAM-based switches.RuleTris employs the dependency graph(DAG)as the key abstraction to minimize the update latency.RuleTris efficiently obtains the DAGs with novel dependency preserving algorithms that incrementally build rule dependency along with the compilation process.Then,in the guidance of the DAG,RuleTris calculates the TCAM update schedules that minimize TCAM entry moves,which are themain cause of TCAM update inefficiency.In evaluation,RuleTris achieves a median of<12 ms and 90-percentile of<15ms the end-to-end perrule update latency on our hardware prototype,outperforming the state-of-the-art composition compiler CoVisor by～20 times.展开更多
In China,the term“black flights”re-fers to unauthorized operations of drones,flying cars and other aircraft.This includes unregistered devices,as well as registered ones flown without approval or beyond permitted zo...In China,the term“black flights”re-fers to unauthorized operations of drones,flying cars and other aircraft.This includes unregistered devices,as well as registered ones flown without approval or beyond permitted zones.Chinese law stipulates clear penalties for such violations,ranging from warnings and fines to criminal liability in serious cases.Despite these regulations,black flights have grown increasingly common in recent years.展开更多
1 Introduction Access control and key update are crucial for secure data sharing.Currently,many access control strategies have been proposed to address unauthorized access and privacy breaches[1,2].However,these strat...1 Introduction Access control and key update are crucial for secure data sharing.Currently,many access control strategies have been proposed to address unauthorized access and privacy breaches[1,2].However,these strategies typically focus only on the unilateral access control of data requesters,potentially failing to prevent unauthorized individuals from maliciously publishing data.Additionally,existing key update schemes rely on trusted key generation center(KGC)and have significant performance limitations,which are not practical[3,4].展开更多
This article develops a comparative analysis of healthcare provision to migrants in the US and in China.It proceeds in three parts.First,we begin by describing the growth of the unauthorized population and trace the e...This article develops a comparative analysis of healthcare provision to migrants in the US and in China.It proceeds in three parts.First,we begin by describing the growth of the unauthorized population and trace the evolution of social provision of healthcare to immigrants,highlighting the restrictive nature of federal social provisions and greater autonomy of state and local governments in redefining eligibility criteria in the US.Second,we examine the impact of legal status on healthcare access and utilization among Mexicans,using original data from the 2007 Hispanic Healthcare Survey and the Mexican Migration Project.We find that unauthorized immigrants report the lowest level of healthcare access and utilization.Third,we then outline a China-US comparative agenda,pointing to similarities between the two migrant flows.In China,recent developments of healthcare coverage for both rural and urban populations have increased access to healthcare,but rural-to-urban migrants still report many barriers in receiving care and are often left out of this growing safety net.We then close with a discussion of lessons learned from the US experience and remaining questions for future comparative research.展开更多
文摘Hadoop technology is followed by some security issues. At its beginnings, developers paid attention to the development of basic functionalities mostly, and proposal of security components was not of prime interest. Because of that, the technology remained vulnerable to malicious activities of unauthorized users whose purpose is to endanger system functionalities or to compromise private user data. Researchers and developers are continuously trying to solve these issues by upgrading Hadoop’s security mechanisms and preventing undesirable malicious activities. In this paper, the most common HDFS security problems and a review of unauthorized access issues are presented. First, Hadoop mechanism and its main components are described as the introduction part of the leading research problem. Then, HDFS architecture is given, and all including components and functionalities are introduced. Further, all possible types of users are listed with an accent on unauthorized users, which are of great importance for the paper. One part of the research is dedicated to the consideration of Hadoop security levels, environment and user assessments. The review also includes an explanation of Log Monitoring and Audit features, and detail consideration of authorization and authentication issues. Possible consequences of unauthorized access to a system are covered, and a few recommendations for solving problems of unauthorized access are offered. Honeypot nodes, security mechanisms for collecting valuable information about malicious parties, are presented in the last part of the paper. Finally, the idea for developing a new type of Intrusion Detector, which will be based on using an artificial neural network, is presented. The detector will be an integral part of a new kind of virtual honeypot mechanism and represents the initial base for future scientific work of authors.
文摘The act of unauthorized siting of buildings has persisted in most developing countries. Despite numerous efforts at local levels to address this problem, its existence and effects keep on rising in various metropolises in Ghana. This research explores the causes of unauthorized siting of buildings in Asakae, a suburb of the Sekondi-Takoradi Metropolis, and suggests measures to curb them. In view of this, a sample size of 182 house-owners was chosen for the study. Accordingly, the sample size was determined using Fisher et al. formula and questionnaire survey approach was adopted for the study. More so, data generated from the survey were further analyzed, using Relative Importance Index. The findings of the survey indicated that ignorance on planning and building regulations, inadequate housing schemes, unrealistic zonings and the location of land are critical variables which influence unauthorized siting of buildings. It is recommended that the populace should be given regular public education on land-use planning and the building regulations of Ghana. More so, the Assemblies should automate their systems, with respect to monitoring and detection of buildings under construction;so that buildings that were being located at unapproved places could be quickly detected, and appropriate measures could be taken before their completion.
基金Supported by the National Natural Science Foundation of China(No.60872041,61072066)Fundamental Research Funds for the Central Universities(JYI0000903001,JYI0000901034)
文摘To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put forward to calculate the uncertainty of the system' s determinations on the irregular access behaviors.Secondly,based on the security entropy,security theorems of hybrid cloud are defined.Finally,typical access control models are analyzed by the method,the method's practicability is validated,and security and applicability of these models are compared.Simulation results prove that the proposed method is suitable for the security quantitative analysis of the access control model and evaluation to access control capability in hybrid cloud.
基金supported by National Key R&D Program of China under Grant No.2017YFB0801703the Key Research and Development Program of Zhejiang Province under Grant No.2018C01088
文摘Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies enables more dynamic management of data center networks.Although the SDN controller architecture is increasingly optimized for swift policy updates,the data plane,especially the prevailing ternary content-addressable memory(TCAM)based flow tables on physical SDN switches,remains unoptimized for fast rule updates,and is gradually becoming the primary bottleneck along the policy update pipeline.In this paper,we present RuleTris,the first SDN update optimization framework that minimizes rule update latency for TCAM-based switches.RuleTris employs the dependency graph(DAG)as the key abstraction to minimize the update latency.RuleTris efficiently obtains the DAGs with novel dependency preserving algorithms that incrementally build rule dependency along with the compilation process.Then,in the guidance of the DAG,RuleTris calculates the TCAM update schedules that minimize TCAM entry moves,which are themain cause of TCAM update inefficiency.In evaluation,RuleTris achieves a median of<12 ms and 90-percentile of<15ms the end-to-end perrule update latency on our hardware prototype,outperforming the state-of-the-art composition compiler CoVisor by～20 times.
文摘In China,the term“black flights”re-fers to unauthorized operations of drones,flying cars and other aircraft.This includes unregistered devices,as well as registered ones flown without approval or beyond permitted zones.Chinese law stipulates clear penalties for such violations,ranging from warnings and fines to criminal liability in serious cases.Despite these regulations,black flights have grown increasingly common in recent years.
基金supported by the National Key R&D Projects(No.2021YFB00900)the National Natural Science Foundation of China(Grant Nos.U20A20174,U22B2062,62302230,62202051,62372068,62302229,and 62302162)the China Postdoctoral Science Foundation(Nos.2021M700435,2024M751480).
文摘1 Introduction Access control and key update are crucial for secure data sharing.Currently,many access control strategies have been proposed to address unauthorized access and privacy breaches[1,2].However,these strategies typically focus only on the unilateral access control of data requesters,potentially failing to prevent unauthorized individuals from maliciously publishing data.Additionally,existing key update schemes rely on trusted key generation center(KGC)and have significant performance limitations,which are not practical[3,4].
文摘This article develops a comparative analysis of healthcare provision to migrants in the US and in China.It proceeds in three parts.First,we begin by describing the growth of the unauthorized population and trace the evolution of social provision of healthcare to immigrants,highlighting the restrictive nature of federal social provisions and greater autonomy of state and local governments in redefining eligibility criteria in the US.Second,we examine the impact of legal status on healthcare access and utilization among Mexicans,using original data from the 2007 Hispanic Healthcare Survey and the Mexican Migration Project.We find that unauthorized immigrants report the lowest level of healthcare access and utilization.Third,we then outline a China-US comparative agenda,pointing to similarities between the two migrant flows.In China,recent developments of healthcare coverage for both rural and urban populations have increased access to healthcare,but rural-to-urban migrants still report many barriers in receiving care and are often left out of this growing safety net.We then close with a discussion of lessons learned from the US experience and remaining questions for future comparative research.
