Data sharing and privacy securing present extensive opportunities and challenges in vehicular network.This paper introducestrust access authentication scheme’as a mechanism to achieve real-time monitoring and promote...Data sharing and privacy securing present extensive opportunities and challenges in vehicular network.This paper introducestrust access authentication scheme’as a mechanism to achieve real-time monitoring and promote collaborative sharing for vehicles.Blockchain,which can provide secure authentication and protected privacy,is a crucial technology.However,traditional cloud computing performs poorly in supplying low-latency and fast-response services for moving vehicles.In this situation,edge computing enabled Blockchain network appeals to be a promising method,where moving vehicles can access storage or computing resource and get authenticated from Blockchain edge nodes directly.In this paper,a hierarchical architecture is proposed consist of vehicular network layer,Blockchain edge layer and Blockchain network layer.Through a authentication mechanism adopting digital signature algorithm,it achieves trusted authentication and ensures valid verification.Moreover,a caching scheme based on many-to-many matching is proposed to minimize average delivery delay of vehicles.Simulation results prove that the proposed caching scheme has a better performance than existing schemes based on central-ized model or edge caching strategy in terms of hit ratio and average delay.展开更多
The basic function of the Internet is to delivery data(what) to serve the needs of all applications. IP names the attachment points(where) to facilitate ubiquitous interconnectivity as the current way to deliver data....The basic function of the Internet is to delivery data(what) to serve the needs of all applications. IP names the attachment points(where) to facilitate ubiquitous interconnectivity as the current way to deliver data. The fundamental mismatch between data delivery and naming attachment points leads to a lot of challenges, e.g., mapping from data name to IP address, handling dynamics of underlying topology, scaling up the data distribution, and securing communication, etc. Informationcentric networking(ICN) is proposed to shift the focus of communication paradigm from where to what, by making the named data the first-class citizen in the network, The basic consensus of ICN is to name the data independent from its container(space dimension) and session(time dimension), which breaks the limitation of point-to-point IP semantic. It scales up data distribution by utilizing available resources, and facilitates communication to fit diverse connectivity and heterogeneous networks. However, there are only a few consensuses on the detailed design of ICN, and quite a few different ICN architectures are proposed. This paper reveals the rationales of ICN from the perspective of the Internet evolution, surveys different design choices, and discusses on two debatable topics in ICN, i.e.,self-certifying versus hierarchical names, and edge versus pervasive caching. We hope this survey helps clarify some mis-understandings on ICN and achieve more consensuses.展开更多
A virtual lab system is the simulation of real devices and experiments usingcomputer and network technology. It can make users do experiments easily, observe experimentphenomena and results through the remote terminal...A virtual lab system is the simulation of real devices and experiments usingcomputer and network technology. It can make users do experiments easily, observe experimentphenomena and results through the remote terminal. Consequently, users can get final results toverify relative theory. The article analyses the features of virtual lab systems. A real virtual labsystem named 'Multimedia Virtual Lab for Digital Circuit Logic Design (MVLDCLD)' which has beendeveloped by the authors and their group is also presented.展开更多
A low-than character feature embedding called radical embedding is proposed,and applied on a long-short term memory(LSTM) model for sentence segmentation of pre-modern Chinese texts.The dataset includes over 150 class...A low-than character feature embedding called radical embedding is proposed,and applied on a long-short term memory(LSTM) model for sentence segmentation of pre-modern Chinese texts.The dataset includes over 150 classical Chinese books from 3 different dynasties and contains different literary styles.LSTM-conditional random fields(LSTM-CRF) model is a state-of-the-art method for the sequence labeling problem.This model adds a component of radical embedding,which leads to improved performances.Experimental results based on the aforementioned Chinese books demonstrate better accuracy than earlier methods on sentence segmentation,especial in Tang’s epitaph texts(achieving an F1-score of 81.34%).展开更多
Mobile platform is now widely seen as a promising multimedia service with a favorable user group and market prospect. To study the influence of mobile terminal models on the quality of scene roaming, a parameter setti...Mobile platform is now widely seen as a promising multimedia service with a favorable user group and market prospect. To study the influence of mobile terminal models on the quality of scene roaming, a parameter setting platform of mobile terminal models is established to select the parameter selection and performance index on different mobile platforms in this paper. This test platform is established based on model optimality principle, analyzing the performance curve of mobile terminals in different scene models and then deducing the external parameter of model establishment. Simulation results prove that the established test platform is able to analyze the parameter and performance matching list of a mobile terminal model.展开更多
With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G netw...With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G networks has been widely studied. Although many works have been done, most of the existing works focus on the issues of network resource utilization or the quality of experience (QoE) promotion, while the energy efficiency is largely ignored. In this paper, different from previous works, in order to realize the energy efficiency for video transmission in MEC-enhanced 5G networks, we propose a joint caching and transcoding schedule strategy for HTTP adaptive video streaming transmission by taking the caching and transcoding into consideration. We formulate the problem of energy-efficient joint caching and transcoding as an integer programming problem to minimize the system energy consumption. Due to solving the optimization problem brings huge computation complexity, therefore, to make the optimization problem tractable, a heuristic algorithm based on simulated annealing algorithm is proposed to iteratively reach the global optimum solution with a lower complexity and higher accuracy. Finally, numerical simulation results are illustrated to demonstrated that our proposed scheme brings an excellent performance.展开更多
The Internet of Things(IoT)connects objects to Internet through sensor devices,radio frequency identification devices and other information collection and processing devices to realize information interaction.IoT is w...The Internet of Things(IoT)connects objects to Internet through sensor devices,radio frequency identification devices and other information collection and processing devices to realize information interaction.IoT is widely used in many fields,including intelligent transportation,intelligent healthcare,intelligent home and industry.In these fields,IoT devices connected via high-speed internet for efficient and reliable communications and faster response times.展开更多
To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11 ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, th...To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11 ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, this paper proposed a beam codebook design scheme for phased array to not only satisfy the fast beam searching algorithm's demand, but also make good use of the advantage of the searching algorithm. The simulation results prove that the proposed scheme not only performs well on flexibility and searching time complexity, but also has high success ratio.展开更多
Caching and virtualization have been considered as the promising techniques in 5G Networks. In 5G networks with virtualization, the caching resources deployed by infrastructure providers (InPs) can be abstracted into ...Caching and virtualization have been considered as the promising techniques in 5G Networks. In 5G networks with virtualization, the caching resources deployed by infrastructure providers (InPs) can be abstracted into isolated slices and transparently shared by mobile virtual network operators (MVNOs). In this case, one of the most important issues is how the MVNOs to share the caching resource. To solve this issue, different from previous works, a hierarchical caching architecture that core network and radio access network (RAN) have the caching capability in 5G networks with virtualization is first considered in this paper. Then, we study the problem of hierarchical caching resource sharing for MVNOs, and a competitive game to maximize their expectation revenue based on the oligopoly market model is formulated. As it is a hard problem to find the optimal solution in the hierarchical caching resource sharing problem, we decompose the optimization problem into two independent caching resource sharing problems in RAN and core network, respectively. Then the local optimal solutions are solved and the global Nash equilibrium solution is achieved. Finally, simulation results are illustrated to demonstrate the performance of the proposed scheme.展开更多
In order to expand the cell coverage of wireless cellular systems, the number of passive components in wireless systems has been substantially increased. There can be many passive intermodulation(PIM) pointsources eve...In order to expand the cell coverage of wireless cellular systems, the number of passive components in wireless systems has been substantially increased. There can be many passive intermodulation(PIM) pointsources even in a device or a radio link, which may add up constructively or destructively. A modified point-source model with lossy components is proposed to evaluate the superposition effect of the forward and refl ected PIM in case of series connection. The index of the series connection factor(SCF) is employed for systems that incorporate multiple PIM sources to predict the important characteristics of the cumulative PIM, such as the maximum and minimum values and the limit form. Furthermore, some initial experimental results are given out and the deviation in the above-mentioned prediction is also analyzed.展开更多
With more and more researches about improving BP algorithm, there are more improvement methods. The paper researches two improvement algorithms based on quasi-Newton method, DFP algorithm and L-BFGS algorithm. After f...With more and more researches about improving BP algorithm, there are more improvement methods. The paper researches two improvement algorithms based on quasi-Newton method, DFP algorithm and L-BFGS algorithm. After fully analyzing the features of quasi- Newton methods, the paper improves BP neural network algorithm. And the adjustment is made for the problems in the improvement process. The paper makes empirical analysis and proves the effectiveness of BP neural network algorithm based on quasi-Newton method. The improved algorithms are compared with the traditional BP algorithm, which indicates that the imoroved BP algorithm is better.展开更多
This paper presents a constructive discussion and inclusive review on advancements in the coded modulation free-space optical(FSO) communication system and corresponding techniques. These techniques mainly include cha...This paper presents a constructive discussion and inclusive review on advancements in the coded modulation free-space optical(FSO) communication system and corresponding techniques. These techniques mainly include channel model,forward error correction(FEC) and modulation schemes. Firstly,a complete view of FSO system is presented which contains the description,the current research situation along with the advantages over the traditional radio frequency(RF) wireless communication and fiber optical communications. Then,the channel model,FEC,modulation schemes and complete system of coded modulation FSO are analyzed successively. At last,the review work of coded modulation FSO system is summarized and further improvements are prospected.展开更多
Editorial Over r the past few decades,the demand for the capacity and reliability of optical networks has continued to grow,i.e.,the optical network is expected to be more resource-efficient and more reliable.In the m...Editorial Over r the past few decades,the demand for the capacity and reliability of optical networks has continued to grow,i.e.,the optical network is expected to be more resource-efficient and more reliable.In the meantime,optical networks with larger knowledge scales have become sources of numerous heterogeneous data.展开更多
Network traffic is very important for testing network equipment, network services, and security products. A new method of generating traffic based on statistical packet-level characteristics is proposed. In every time...Network traffic is very important for testing network equipment, network services, and security products. A new method of generating traffic based on statistical packet-level characteristics is proposed. In every time unit, the generator determines the sent packets number, the type and size of every sent packet according to the statistical characteristics of the original traffic. Then every packet, in which the protocol headers of transport layer, network layer and ethernet layer are encapsulated, is sent via the responding network interface card in the time unit. The results in the experiment show that the correlation coefficients between the bandwidth, the packet number, packet size distribution, the fragment number of the generated network traffic and those of the original traffic are all more than 0.96. The generated traffic and original traffic are very highly related and similar.展开更多
We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells （MQWs） laser at 1.55 pm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are g...We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells （MQWs） laser at 1.55 pm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are grown on GaAs substrates by low-pressure metal organic chemical vapor deposition technology. Then, high- quality MQWs laser structures are grown on the InP buffer layer. Under quasi-continuous wave （QCW） condition, a threshold current of 476 mA and slope efficiency of 0.15 mW/mA are achieved for a broad area device with 50 μm wide strip and 500 μm long cavity at room-temperature. The peak wavelength of emission spectrum is 1549.5 nm at 700 mA. The device is operating for more than 2000 h at room-temperature and 600 mA.展开更多
Wo T(Web of Things) integrates smart devices into Web by reusing and extending Web standards. While Web technology makes the developers' job easier,it faces security,management and efficiency challenges. We propos...Wo T(Web of Things) integrates smart devices into Web by reusing and extending Web standards. While Web technology makes the developers' job easier,it faces security,management and efficiency challenges. We propose Wo T/SDN,the architecture of resource oriented Wo T built on SDN(Software Defined Network),in which applications could be developed through resource subscription and Mashup with the programmability provided by SDN. The key components are designed,including Security and Management Controller(SMC),various atomic services and resource subscription syntax. Three applications covering device management,data access and security protection are demonstrated. Compared to traditional resource-oriented Wo T systems,our test results show that SDN,with its logically centralized control capability and awareness of flow forwarding,provides new opportunity to improve performance,simplify management and enhance security for Wo T.展开更多
with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this...with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation(DIV) framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine's architecture stack.DIV introduces a trusted third party(TTP) to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.展开更多
To extensively deploy quantum key distribution（QKD） systems, copropagating with classical channels on the same fiber using wavelength division multiplexing（WDM） technology becomes a critical issue. We propose a us...To extensively deploy quantum key distribution（QKD） systems, copropagating with classical channels on the same fiber using wavelength division multiplexing（WDM） technology becomes a critical issue. We propose a user-based channel-interleaving WDM scheme with unequal frequency spacing（UFS-i WDM） to reduce the impairment on the quantum channels induced by four-wave mixing（FWM）, and theoretically analyze its impact on quantum bit error rate（QBER）. Numerical simulation results show that a UFS-i WDM can significantly reduce the FWM noise and improve QBER compared with the corresponding WDM scheme with equal frequency spacing（EFS）, especially in the case of nonzero dispersion shifted fiber.展开更多
Many improved authentication solutions were put forward, on purpose of authenticating more quickly and securely.However, neither the overuse of hash function,or additional symmetric encryption, can truly increase the ...Many improved authentication solutions were put forward, on purpose of authenticating more quickly and securely.However, neither the overuse of hash function,or additional symmetric encryption, can truly increase the overall security. Instead,extra computation cost degraded the performance.They were still vulnerable to a variety of threats, such as smart card loss attack and impersonation attack, due to hidden loopholes and flaws. Even worse, user's identity can be parsed in insecure environment, even became traceable. Aiming to protect identity, a lightweight mutual authentication scheme is proposed. Redundant operations are removed,which make the verification process more explicit. It gains better performance with average cost compared to other similar schemes.Cryptanalysis shows the proposed scheme can resist common attacks and achieve user anonymity.Formal security is further verified by using the widely accepted Automated Validation of Internet Security Protocols and Applications(AVISPA) tool.展开更多
基金support by Research on Key Technologies of Dynamically Secure Identity Authentication and Risk Control of Power Business in the Science and Technology Project of State Grid Electric Power Company(No.5204XA19003F)National Natural Science Foundation of China(Grant No.601702048)
文摘Data sharing and privacy securing present extensive opportunities and challenges in vehicular network.This paper introducestrust access authentication scheme’as a mechanism to achieve real-time monitoring and promote collaborative sharing for vehicles.Blockchain,which can provide secure authentication and protected privacy,is a crucial technology.However,traditional cloud computing performs poorly in supplying low-latency and fast-response services for moving vehicles.In this situation,edge computing enabled Blockchain network appeals to be a promising method,where moving vehicles can access storage or computing resource and get authenticated from Blockchain edge nodes directly.In this paper,a hierarchical architecture is proposed consist of vehicular network layer,Blockchain edge layer and Blockchain network layer.Through a authentication mechanism adopting digital signature algorithm,it achieves trusted authentication and ensures valid verification.Moreover,a caching scheme based on many-to-many matching is proposed to minimize average delivery delay of vehicles.Simulation results prove that the proposed caching scheme has a better performance than existing schemes based on central-ized model or edge caching strategy in terms of hit ratio and average delay.
基金supported by the National High-tech R&D Program("863"Program)of China(No.2013AA013505)the National Science Foundation of China(No.61472213)State Scholarship Fund from China Scholarship Council(No.201406210270)
文摘The basic function of the Internet is to delivery data(what) to serve the needs of all applications. IP names the attachment points(where) to facilitate ubiquitous interconnectivity as the current way to deliver data. The fundamental mismatch between data delivery and naming attachment points leads to a lot of challenges, e.g., mapping from data name to IP address, handling dynamics of underlying topology, scaling up the data distribution, and securing communication, etc. Informationcentric networking(ICN) is proposed to shift the focus of communication paradigm from where to what, by making the named data the first-class citizen in the network, The basic consensus of ICN is to name the data independent from its container(space dimension) and session(time dimension), which breaks the limitation of point-to-point IP semantic. It scales up data distribution by utilizing available resources, and facilitates communication to fit diverse connectivity and heterogeneous networks. However, there are only a few consensuses on the detailed design of ICN, and quite a few different ICN architectures are proposed. This paper reveals the rationales of ICN from the perspective of the Internet evolution, surveys different design choices, and discusses on two debatable topics in ICN, i.e.,self-certifying versus hierarchical names, and edge versus pervasive caching. We hope this survey helps clarify some mis-understandings on ICN and achieve more consensuses.
文摘A virtual lab system is the simulation of real devices and experiments usingcomputer and network technology. It can make users do experiments easily, observe experimentphenomena and results through the remote terminal. Consequently, users can get final results toverify relative theory. The article analyses the features of virtual lab systems. A real virtual labsystem named 'Multimedia Virtual Lab for Digital Circuit Logic Design (MVLDCLD)' which has beendeveloped by the authors and their group is also presented.
基金supported by the Fund of the key laboratory of rich-media knowledge organization and service of digital publishing content ( ZD2018-07 /05)
文摘A low-than character feature embedding called radical embedding is proposed,and applied on a long-short term memory(LSTM) model for sentence segmentation of pre-modern Chinese texts.The dataset includes over 150 classical Chinese books from 3 different dynasties and contains different literary styles.LSTM-conditional random fields(LSTM-CRF) model is a state-of-the-art method for the sequence labeling problem.This model adds a component of radical embedding,which leads to improved performances.Experimental results based on the aforementioned Chinese books demonstrate better accuracy than earlier methods on sentence segmentation,especial in Tang’s epitaph texts(achieving an F1-score of 81.34%).
基金Supported by National Natural Science Foundation of China(61163044)Xinjiang Uygur Autonomous Xinjiang Science and Technology Projects(2014211A046)+1 种基金Philosophy and Social Key Fund Project(12AZD118,12AZD120)Beijing Excellent Talents(2010D005022000011)
文摘Mobile platform is now widely seen as a promising multimedia service with a favorable user group and market prospect. To study the influence of mobile terminal models on the quality of scene roaming, a parameter setting platform of mobile terminal models is established to select the parameter selection and performance index on different mobile platforms in this paper. This test platform is established based on model optimality principle, analyzing the performance curve of mobile terminals in different scene models and then deducing the external parameter of model establishment. Simulation results prove that the established test platform is able to analyze the parameter and performance matching list of a mobile terminal model.
基金support by the Major National Science and Technology Projects (No. 2018ZX03001014-003)
文摘With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G networks has been widely studied. Although many works have been done, most of the existing works focus on the issues of network resource utilization or the quality of experience (QoE) promotion, while the energy efficiency is largely ignored. In this paper, different from previous works, in order to realize the energy efficiency for video transmission in MEC-enhanced 5G networks, we propose a joint caching and transcoding schedule strategy for HTTP adaptive video streaming transmission by taking the caching and transcoding into consideration. We formulate the problem of energy-efficient joint caching and transcoding as an integer programming problem to minimize the system energy consumption. Due to solving the optimization problem brings huge computation complexity, therefore, to make the optimization problem tractable, a heuristic algorithm based on simulated annealing algorithm is proposed to iteratively reach the global optimum solution with a lower complexity and higher accuracy. Finally, numerical simulation results are illustrated to demonstrated that our proposed scheme brings an excellent performance.
文摘The Internet of Things(IoT)connects objects to Internet through sensor devices,radio frequency identification devices and other information collection and processing devices to realize information interaction.IoT is widely used in many fields,including intelligent transportation,intelligent healthcare,intelligent home and industry.In these fields,IoT devices connected via high-speed internet for efficient and reliable communications and faster response times.
基金supported by National Natural Science Foundation of China under Grants No.61171104
文摘To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11 ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, this paper proposed a beam codebook design scheme for phased array to not only satisfy the fast beam searching algorithm's demand, but also make good use of the advantage of the searching algorithm. The simulation results prove that the proposed scheme not only performs well on flexibility and searching time complexity, but also has high success ratio.
基金support by the Major National Science and Technology Projects (No. 2018ZX03001019-003, 2018ZX03001014-003)
文摘Caching and virtualization have been considered as the promising techniques in 5G Networks. In 5G networks with virtualization, the caching resources deployed by infrastructure providers (InPs) can be abstracted into isolated slices and transparently shared by mobile virtual network operators (MVNOs). In this case, one of the most important issues is how the MVNOs to share the caching resource. To solve this issue, different from previous works, a hierarchical caching architecture that core network and radio access network (RAN) have the caching capability in 5G networks with virtualization is first considered in this paper. Then, we study the problem of hierarchical caching resource sharing for MVNOs, and a competitive game to maximize their expectation revenue based on the oligopoly market model is formulated. As it is a hard problem to find the optimal solution in the hierarchical caching resource sharing problem, we decompose the optimization problem into two independent caching resource sharing problems in RAN and core network, respectively. Then the local optimal solutions are solved and the global Nash equilibrium solution is achieved. Finally, simulation results are illustrated to demonstrate the performance of the proposed scheme.
文摘In order to expand the cell coverage of wireless cellular systems, the number of passive components in wireless systems has been substantially increased. There can be many passive intermodulation(PIM) pointsources even in a device or a radio link, which may add up constructively or destructively. A modified point-source model with lossy components is proposed to evaluate the superposition effect of the forward and refl ected PIM in case of series connection. The index of the series connection factor(SCF) is employed for systems that incorporate multiple PIM sources to predict the important characteristics of the cumulative PIM, such as the maximum and minimum values and the limit form. Furthermore, some initial experimental results are given out and the deviation in the above-mentioned prediction is also analyzed.
文摘With more and more researches about improving BP algorithm, there are more improvement methods. The paper researches two improvement algorithms based on quasi-Newton method, DFP algorithm and L-BFGS algorithm. After fully analyzing the features of quasi- Newton methods, the paper improves BP neural network algorithm. And the adjustment is made for the problems in the improvement process. The paper makes empirical analysis and proves the effectiveness of BP neural network algorithm based on quasi-Newton method. The improved algorithms are compared with the traditional BP algorithm, which indicates that the imoroved BP algorithm is better.
基金supported in part by the National NSFC with No. 61425022National High Technology 863 Program of China with No. 2013AA013403+5 种基金National Basic Research Program of China with No. 2010CB328300National NSFC (No. 60932004,61275074,61275158,& 61201151)National International Technology Cooperation with No.2012DFG1210Universities Ph.D. Special Research Funds with No. 20120005120007Beijing Excellent Ph.D. Thesis Guidance Foundation with No. 20121001302Open foundation of state key laboratory of optical communication technologies and networks(WRI)
文摘This paper presents a constructive discussion and inclusive review on advancements in the coded modulation free-space optical(FSO) communication system and corresponding techniques. These techniques mainly include channel model,forward error correction(FEC) and modulation schemes. Firstly,a complete view of FSO system is presented which contains the description,the current research situation along with the advantages over the traditional radio frequency(RF) wireless communication and fiber optical communications. Then,the channel model,FEC,modulation schemes and complete system of coded modulation FSO are analyzed successively. At last,the review work of coded modulation FSO system is summarized and further improvements are prospected.
文摘Editorial Over r the past few decades,the demand for the capacity and reliability of optical networks has continued to grow,i.e.,the optical network is expected to be more resource-efficient and more reliable.In the meantime,optical networks with larger knowledge scales have become sources of numerous heterogeneous data.
基金supported in part by national science and technology major project of the ministry of science and technology of China No. 2012BAH45B01Fundamental Research Funds for the Central Universities No. 2014ZD03-03
文摘Network traffic is very important for testing network equipment, network services, and security products. A new method of generating traffic based on statistical packet-level characteristics is proposed. In every time unit, the generator determines the sent packets number, the type and size of every sent packet according to the statistical characteristics of the original traffic. Then every packet, in which the protocol headers of transport layer, network layer and ethernet layer are encapsulated, is sent via the responding network interface card in the time unit. The results in the experiment show that the correlation coefficients between the bandwidth, the packet number, packet size distribution, the fragment number of the generated network traffic and those of the original traffic are all more than 0.96. The generated traffic and original traffic are very highly related and similar.
基金supported by the National Natural Science Foundation of China(Nos.61274044 and61020106007)the National Basic Research Program of China(No.2010CB327600)+3 种基金the Natural Science Foundational Science and Technology Cooperation Projects(No.2011RR000100)the 111 Project of China(No.B07005)the Fundamental Research Funds for the Central University(No.2013RC1205)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130005130001)
文摘We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells （MQWs） laser at 1.55 pm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are grown on GaAs substrates by low-pressure metal organic chemical vapor deposition technology. Then, high- quality MQWs laser structures are grown on the InP buffer layer. Under quasi-continuous wave （QCW） condition, a threshold current of 476 mA and slope efficiency of 0.15 mW/mA are achieved for a broad area device with 50 μm wide strip and 500 μm long cavity at room-temperature. The peak wavelength of emission spectrum is 1549.5 nm at 700 mA. The device is operating for more than 2000 h at room-temperature and 600 mA.
基金supported by National 863 Project SS2015AA011709
文摘Wo T(Web of Things) integrates smart devices into Web by reusing and extending Web standards. While Web technology makes the developers' job easier,it faces security,management and efficiency challenges. We propose Wo T/SDN,the architecture of resource oriented Wo T built on SDN(Software Defined Network),in which applications could be developed through resource subscription and Mashup with the programmability provided by SDN. The key components are designed,including Security and Management Controller(SMC),various atomic services and resource subscription syntax. Three applications covering device management,data access and security protection are demonstrated. Compared to traditional resource-oriented Wo T systems,our test results show that SDN,with its logically centralized control capability and awareness of flow forwarding,provides new opportunity to improve performance,simplify management and enhance security for Wo T.
基金Supported by the National Natural Science Foundation of China under Grant No. 61370068
文摘with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation(DIV) framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine's architecture stack.DIV introduces a trusted third party(TTP) to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.
基金supported by the National Natural Science Foundation of China under Grant No.61331008
文摘To extensively deploy quantum key distribution（QKD） systems, copropagating with classical channels on the same fiber using wavelength division multiplexing（WDM） technology becomes a critical issue. We propose a user-based channel-interleaving WDM scheme with unequal frequency spacing（UFS-i WDM） to reduce the impairment on the quantum channels induced by four-wave mixing（FWM）, and theoretically analyze its impact on quantum bit error rate（QBER）. Numerical simulation results show that a UFS-i WDM can significantly reduce the FWM noise and improve QBER compared with the corresponding WDM scheme with equal frequency spacing（EFS）, especially in the case of nonzero dispersion shifted fiber.
基金supported by the National Key Research and Development Program of China (No. 2017YFC0820603)
文摘Many improved authentication solutions were put forward, on purpose of authenticating more quickly and securely.However, neither the overuse of hash function,or additional symmetric encryption, can truly increase the overall security. Instead,extra computation cost degraded the performance.They were still vulnerable to a variety of threats, such as smart card loss attack and impersonation attack, due to hidden loopholes and flaws. Even worse, user's identity can be parsed in insecure environment, even became traceable. Aiming to protect identity, a lightweight mutual authentication scheme is proposed. Redundant operations are removed,which make the verification process more explicit. It gains better performance with average cost compared to other similar schemes.Cryptanalysis shows the proposed scheme can resist common attacks and achieve user anonymity.Formal security is further verified by using the widely accepted Automated Validation of Internet Security Protocols and Applications(AVISPA) tool.
