Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two line...Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.展开更多
A class of plateaued functions has been got by using the Maiorana-McFarland construction. A variety of desirable criteria for functions with cryptographic application eouht be satisfied： balancedness, high nonlineari...A class of plateaued functions has been got by using the Maiorana-McFarland construction. A variety of desirable criteria for functions with cryptographic application eouht be satisfied： balancedness, high nonlinearity, correlation immunity of reasonably high order, strict avalanche criterion, non-existence of non-zero linear struetures, good glnbal avalanche characteristics, etc.展开更多
We propose a simple scheme to not only generate GHZ states and W states of the multiparticle but also form a new category of multiparticle entangled states by letting the A-type three-level atoms simultaneously intera...We propose a simple scheme to not only generate GHZ states and W states of the multiparticle but also form a new category of multiparticle entangled states by letting the A-type three-level atoms simultaneously interacting with a coherent cavity field followed by the selective measurements on the cavity mode. We investigate the influence of the cavity dissipation on the generated entangled state and discuss the experimental feasibility of our scheme. It is shown that the intensity of the coherent cavity field plays an instructive role in contribution to state preparation process while the cavity decay and the detuning between the atoms and cavity mode result in the deterioration of the generated entangled state.展开更多
The case when the source of information provides precise belief function/mass, within the generalized power space, has been studied by many people. However, in many decision situations, the precise belief structure is...The case when the source of information provides precise belief function/mass, within the generalized power space, has been studied by many people. However, in many decision situations, the precise belief structure is not always available. In this case, an interval-valued belief degree rather than a precise one may be provided. So, the probabilistic transformation of imprecise belief function/mass in the generalized power space including Dezert-Smarandache （DSm） model from scalar transformation to sub-unitary interval transformation and, more generally, to any set of sub-unitary interval transformation is provided. Different from the existing probabilistic transformation algorithms that redistribute an ignorance mass to the singletons involved in that ignorance pro- portionally with respect to the precise belief function or probability function of singleton, the new algorithm provides an optimization idea to transform any type of imprecise belief assignment which may be represented by the union of several sub-unitary （half-） open intervals, （half-） closed intervals and/or sets of points belonging to [0,1]. Numerical examples are provided to illustrate the detailed implementation process of the new probabilistic transformation approach as well as its validity and wide applicability.展开更多
We propose a physical scheme for generating a two-atom cluster state through the simultaneous interaction of two two-level atoms with a single-mode cavity field prepared initially in an odd-coherent state under a larg...We propose a physical scheme for generating a two-atom cluster state through the simultaneous interaction of two two-level atoms with a single-mode cavity field prepared initially in an odd-coherent state under a large-detuned limit. The influence of the dissipation constant, the intensity of the field and the imperfect manipulation on the preparation scheme are investigated. It is shown that when the intensity of the cavity is large enough, the influence of the cavity decay is ettlciently suppressed. The possible error in the implementation of the cluster state is negligible when the time difference between two atoms crossing the cavity axis is small. It is suggested that the scheme can be realized by current technologies.展开更多
With the evolution of the communication standards, Software Defined Radio (SDR) is faced with an increasingly important problem to balance more and more complex wireless communication algorithms against relatively lim...With the evolution of the communication standards, Software Defined Radio (SDR) is faced with an increasingly important problem to balance more and more complex wireless communication algorithms against relatively limited processing capability of hardware. And, the competition for computing resources exacerbates the problem and increases time-delay of SDR system. This paper presents an integrated optimization method for the real-time performance of SDR on Linux OS (operating system). The method is composed of three parts: real-time scheduling policy which ensures higher priority for SDR tasks, CGROUPS used to manage and redistribute the computing resources, and fine-grade system timer which makes the process preemption more accurate. According to the experiments, the round-trip data transfer latency decreases low enough to meet the requirement for TD-SCDMA via the application of the method.展开更多
The presence of systematic measuring errors complicates track-to-track association, spatially separates the tracks that correspond to the same true target, and seriously decline the performances of traditional track-t...The presence of systematic measuring errors complicates track-to-track association, spatially separates the tracks that correspond to the same true target, and seriously decline the performances of traditional track-to-track association algorithms. Consequently, the influence of radar systematic errors on tracks from different radars, which is described as some rotation and translation, has been analyzed theoretically in this paper. In addition, a novel approach named alignment-correlation method is developed to estimate and reduce this effect, align and correlate tracks accurately without prior registration using phase correlation technique and statistic binary track correlation algorithm. Monte-Carlo simulation results illustrate that the proposed algorithm has good performance in solving the track-to-track association problem with systematic errors in radar network and could provide effective and reliable associated tracks for the next step of registration.展开更多
According to the characteristic of Beidou Double-star positing system (for short: Double-star position), the optimal predication model of Double-star position/SINS integrated system is put forward, which can make use ...According to the characteristic of Beidou Double-star positing system (for short: Double-star position), the optimal predication model of Double-star position/SINS integrated system is put forward, which can make use of the delayed position in-formation from Double-star positioning system to predicate optimally for the integrated system, and then to correct SINS, and af-fords integrated results of some navigation parameters. In order to validate the consistency of the filter, the criteria for consistency of a filter is also studied, and the tested statistics are given, the experiment based on practical measured data shows that the filtering method is consistent with the integrated system.展开更多
This paper proposes a simple scheme for realizing one-qubit and two-qubit quantum gates as well as multiqubit entanglement based on de-SQUID charge qubits through the control of their coupling to a 1D transmission lin...This paper proposes a simple scheme for realizing one-qubit and two-qubit quantum gates as well as multiqubit entanglement based on de-SQUID charge qubits through the control of their coupling to a 1D transmission line resonator （TLR）. The TLR behaves effectively as a quantum data-bus mode of a harmonic oscillator, which has several practical advantages including strong coupling strength, reproducibility, immunity to 1/f noise, and suppressed spontaneous emission. In this protocol, the data-bus does not need to stay adiabatically in its ground state, which results in not only fast quantum operation, hut also high-fidelity quantum information processing. Also, it elaborates the transfer process with the 1D transmission line.展开更多
Present mobile communication system suffers from the exponentially increased mobile traffic and research on the fifth generation(5G) mobile network architectures is ongoing to solve this problem. We investigate the fe...Present mobile communication system suffers from the exponentially increased mobile traffic and research on the fifth generation(5G) mobile network architectures is ongoing to solve this problem. We investigate the feasibility of the proposals used for the network architecture evolution from 4G to 5G and first propose a compatible network architecture, which decouples the management plane, the control plane and the user plane based on NO Stack framework proposed in our previous study. We mainly design detail procedures including UE attachment, service request and dedicated bearer activation/deactivation for our proposal network architecture. Finally, we establish a clear analytical mode of the application and system states to evaluate the signaling loads of new architecture. Simulation results show that our proposal network architecture with elaborated signaling procedures has much impact on the total signaling loads of system and could obviously decrease the signaling overhead compared with LTE.展开更多
The relation between the excitonic purity and the concurrence in a system of two coupled large semiconduction quantum dots mediated by a single-mode cavity field is investigated by using linear entropy theory. The res...The relation between the excitonic purity and the concurrence in a system of two coupled large semiconduction quantum dots mediated by a single-mode cavity field is investigated by using linear entropy theory. The results show the difference in describing two modes of excitonic entanglement between linear entropy and concurrence. The relation between nonclassical property of cavity field and the entanglement degree of excitons is also discussed. The results show that two modes of exciton can reach maximal entanglement when the cavity exhibits an antibunching effect.展开更多
Passive filtering of neural networks with time-invariant delay and quantized output is considered.A criterion on the passivity of a filtering error system is proposed by means of the Lyapunov-Krasovskii functional and...Passive filtering of neural networks with time-invariant delay and quantized output is considered.A criterion on the passivity of a filtering error system is proposed by means of the Lyapunov-Krasovskii functional and the Bessel-Legendre inequality.Based on the criterion,a design approach for desired passive filters is developed in terms of the feasible solution of a set of linear matrix inequalities.Then,analyses and syntheses are extended to the time-variant delay situation using the reciprocally convex combination inequality.Finally,a numerical example with simulations is used to illustrate the applicability and reduced conservatism of the present passive filter design approaches.展开更多
We present a scheme for generating four pairs of two-atom Einstein Podolsky-Rosen （EPR） states using the simultaneous interaction of the two atoms with a single-mode cavity field under a large detuning condition. Th...We present a scheme for generating four pairs of two-atom Einstein Podolsky-Rosen （EPR） states using the simultaneous interaction of the two atoms with a single-mode cavity field under a large detuning condition. The influence of cavity dissipation on the prepared EPR states is investigated by means of the superoperator method and the state fidelity. It is shown that some kinds of the prepared EPR states are robust against cavity dissipation and the intensity of the field, and maintain their entanglement invariance, and the others are fragile and completely destroyed by the action of cavity dissipation and the intensity of the field in the long-time limit. Decoherence time of the fragile entangled states is extremely small for a typical cavity-QED experimental data.展开更多
We theoretically study the properties of the ground state of the parallel-coupled double quantum dots embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonia...We theoretically study the properties of the ground state of the parallel-coupled double quantum dots embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the persistent current depends sensitively on both the parity of this system and the size of the ring. In the strong coupling regime, the giant sharp current peak appears, at the same time, the parity dependence of the persistent current disappears. These imply that in the strong coupling regime, there exists giant Kondo resonance and the two dots can be coupled coherently. Thus this system might be a candidate for future device applications.展开更多
Quantum entanglement and nonlocality properties of a family of two-mode Gaussian pure states have been investigated. The results show that the entanglement of these states is determined by both the two-mode squeezing ...Quantum entanglement and nonlocality properties of a family of two-mode Gaussian pure states have been investigated. The results show that the entanglement of these states is determined by both the two-mode squeezing parameter and the difference of the two single-mode squeezing parameters. For the same two-mode squeezing parameter, these states show larger entanglement than the usual two-mode squeezed vacuum state. The violation of Bell inequality depends strongly on all the squeezing parameters of these states and disappears completely in the limit of large squeezing. In particular, these states can exhibit much stronger violation of local realism than two-mode squeezed vacuum state in the range of experimentally available squeezing values.展开更多
By extracting the control plane from the data plane, SDN en?ables unprecedented flexibility for future network architec?tures and quickly changes the landscape of the networking industry. Although the maturity of comm...By extracting the control plane from the data plane, SDN en?ables unprecedented flexibility for future network architec?tures and quickly changes the landscape of the networking industry. Although the maturity of commonly accepted SDN security practices is the key to the proliferation of cloud DCN, SDN security research is still in its infancy. This pa?per gives a top?down survey of the approaches in this area, discussing security challenges and opportunities of software?defined datacenter networking for cloud computing. It lever?ages the well?known confidentiality?integrity?availability (CIA) matrix and protection?detection?reaction (PDR) model to give an overview of current security threats and security mea?sures. It also discusses promising research directions in this field.展开更多
We theoretically investigate the Kondo effect of a three-terminal transport quantum dot （QD） embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. The Hamiltonian i...We theoretically investigate the Kondo effect of a three-terminal transport quantum dot （QD） embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the Kondo effect depends sensitively oil the parity and size of the ring; the Kondo screening cloud can be tuned by tuning the coupling strength of the reservoir-dot. Thus this model might be a candidate for future device applications.展开更多
This paper constructs the probability model of Gunther generator at first, and the finite dimension union distribution of the output sequence is presented. The result shows that the output sequence is an independent a...This paper constructs the probability model of Gunther generator at first, and the finite dimension union distribution of the output sequence is presented. The result shows that the output sequence is an independent and uniformly distributed 0,1 random variable sequence. It gives the theoretical foundation about why Gunther generator can avoid the statistic weakness of the output sequence of stop-and-go generator, and analyzes the coincidence between output sequence and input sequences of Gunther generator. The conclusions of this paper would offer theoretical references for designers and analyzers of clock-controlled generators.展开更多
Based on a new adaptive Particle Swarm Optimization algorithm with dynamically changing inertia weight (DAPSO), It is used to optimize parameters in PID controller. Compared to conventional PID methods, the simulation...Based on a new adaptive Particle Swarm Optimization algorithm with dynamically changing inertia weight (DAPSO), It is used to optimize parameters in PID controller. Compared to conventional PID methods, the simulation shows that this new method makes the optimization perfectly and convergence quickly.展开更多
基金supported by the National Natural Science Foundation of China(61971432)Taishan Scholar Project of Shandong Province(tsqn201909156)the Outstanding Youth Innovation Team Program of University in Shandong Province(2019KJN031)。
文摘Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.
基金the National Natural Science Foundation of China，Foundation of National Laboratory for Modern Communications
文摘A class of plateaued functions has been got by using the Maiorana-McFarland construction. A variety of desirable criteria for functions with cryptographic application eouht be satisfied： balancedness, high nonlinearity, correlation immunity of reasonably high order, strict avalanche criterion, non-existence of non-zero linear struetures, good glnbal avalanche characteristics, etc.
基金Supported by the Natural Science Foundation of Hunan Province under Grant No.06jj50014Key Project Foundation of the Education Commission of Hunan Province under Grant No.06A055the Young Core Teachers Foundation of Hunan Provincial Education Department
文摘We propose a simple scheme to not only generate GHZ states and W states of the multiparticle but also form a new category of multiparticle entangled states by letting the A-type three-level atoms simultaneously interacting with a coherent cavity field followed by the selective measurements on the cavity mode. We investigate the influence of the cavity dissipation on the generated entangled state and discuss the experimental feasibility of our scheme. It is shown that the intensity of the coherent cavity field plays an instructive role in contribution to state preparation process while the cavity decay and the detuning between the atoms and cavity mode result in the deterioration of the generated entangled state.
基金supported by the National Natural Science Foundation of China (60572161 60874105)+5 种基金the Excellent Ph.D. Paper Author Foundation of China (200443)the Postdoctoral Science Foundation of China (20070421094)the Program for New Century Excellent Talents in University (NCET-08-0345)the Shanghai Rising-Star Program(09QA1402900)the "Chenxing" Scholarship Youth Found of Shanghai Jiaotong University (T241460612)the Ministry of Education Key Laboratory of Intelligent Computing & Signal Processing (2009ICIP03)
文摘The case when the source of information provides precise belief function/mass, within the generalized power space, has been studied by many people. However, in many decision situations, the precise belief structure is not always available. In this case, an interval-valued belief degree rather than a precise one may be provided. So, the probabilistic transformation of imprecise belief function/mass in the generalized power space including Dezert-Smarandache （DSm） model from scalar transformation to sub-unitary interval transformation and, more generally, to any set of sub-unitary interval transformation is provided. Different from the existing probabilistic transformation algorithms that redistribute an ignorance mass to the singletons involved in that ignorance pro- portionally with respect to the precise belief function or probability function of singleton, the new algorithm provides an optimization idea to transform any type of imprecise belief assignment which may be represented by the union of several sub-unitary （half-） open intervals, （half-） closed intervals and/or sets of points belonging to [0,1]. Numerical examples are provided to illustrate the detailed implementation process of the new probabilistic transformation approach as well as its validity and wide applicability.
基金Supported by the Natural Science Foundation of the Education Department of Hunan Province under Grant No 05C696.
文摘We propose a physical scheme for generating a two-atom cluster state through the simultaneous interaction of two two-level atoms with a single-mode cavity field prepared initially in an odd-coherent state under a large-detuned limit. The influence of the dissipation constant, the intensity of the field and the imperfect manipulation on the preparation scheme are investigated. It is shown that when the intensity of the cavity is large enough, the influence of the cavity decay is ettlciently suppressed. The possible error in the implementation of the cluster state is negligible when the time difference between two atoms crossing the cavity axis is small. It is suggested that the scheme can be realized by current technologies.
文摘With the evolution of the communication standards, Software Defined Radio (SDR) is faced with an increasingly important problem to balance more and more complex wireless communication algorithms against relatively limited processing capability of hardware. And, the competition for computing resources exacerbates the problem and increases time-delay of SDR system. This paper presents an integrated optimization method for the real-time performance of SDR on Linux OS (operating system). The method is composed of three parts: real-time scheduling policy which ensures higher priority for SDR tasks, CGROUPS used to manage and redistribute the computing resources, and fine-grade system timer which makes the process preemption more accurate. According to the experiments, the round-trip data transfer latency decreases low enough to meet the requirement for TD-SCDMA via the application of the method.
文摘The presence of systematic measuring errors complicates track-to-track association, spatially separates the tracks that correspond to the same true target, and seriously decline the performances of traditional track-to-track association algorithms. Consequently, the influence of radar systematic errors on tracks from different radars, which is described as some rotation and translation, has been analyzed theoretically in this paper. In addition, a novel approach named alignment-correlation method is developed to estimate and reduce this effect, align and correlate tracks accurately without prior registration using phase correlation technique and statistic binary track correlation algorithm. Monte-Carlo simulation results illustrate that the proposed algorithm has good performance in solving the track-to-track association problem with systematic errors in radar network and could provide effective and reliable associated tracks for the next step of registration.
文摘According to the characteristic of Beidou Double-star positing system (for short: Double-star position), the optimal predication model of Double-star position/SINS integrated system is put forward, which can make use of the delayed position in-formation from Double-star positioning system to predicate optimally for the integrated system, and then to correct SINS, and af-fords integrated results of some navigation parameters. In order to validate the consistency of the filter, the criteria for consistency of a filter is also studied, and the tested statistics are given, the experiment based on practical measured data shows that the filtering method is consistent with the integrated system.
基金supported by Hunan Provincial Natural Science Foundation of China (Grant No 06JJ50014)the Key Project Foundation of the Education Commission of Hunan Province of China (Grant No 06A055)
文摘This paper proposes a simple scheme for realizing one-qubit and two-qubit quantum gates as well as multiqubit entanglement based on de-SQUID charge qubits through the control of their coupling to a 1D transmission line resonator （TLR）. The TLR behaves effectively as a quantum data-bus mode of a harmonic oscillator, which has several practical advantages including strong coupling strength, reproducibility, immunity to 1/f noise, and suppressed spontaneous emission. In this protocol, the data-bus does not need to stay adiabatically in its ground state, which results in not only fast quantum operation, hut also high-fidelity quantum information processing. Also, it elaborates the transfer process with the 1D transmission line.
基金supported by the Chinas 863 Project (No.2015AA01A706)the National Science and Technology Major Project (No. 2016ZX03001017)+1 种基金the Science and Technology Program of Beijing (No. D161100001016002)the Science and Technology Cooperation Projects (No. 2015DFT10160B)
文摘Present mobile communication system suffers from the exponentially increased mobile traffic and research on the fifth generation(5G) mobile network architectures is ongoing to solve this problem. We investigate the feasibility of the proposals used for the network architecture evolution from 4G to 5G and first propose a compatible network architecture, which decouples the management plane, the control plane and the user plane based on NO Stack framework proposed in our previous study. We mainly design detail procedures including UE attachment, service request and dedicated bearer activation/deactivation for our proposal network architecture. Finally, we establish a clear analytical mode of the application and system states to evaluate the signaling loads of new architecture. Simulation results show that our proposal network architecture with elaborated signaling procedures has much impact on the total signaling loads of system and could obviously decrease the signaling overhead compared with LTE.
基金Project supported by the Scientific Research Fund of Education Bureau of Hunan Province (Grant No 05C696)
文摘The relation between the excitonic purity and the concurrence in a system of two coupled large semiconduction quantum dots mediated by a single-mode cavity field is investigated by using linear entropy theory. The results show the difference in describing two modes of excitonic entanglement between linear entropy and concurrence. The relation between nonclassical property of cavity field and the entanglement degree of excitons is also discussed. The results show that two modes of exciton can reach maximal entanglement when the cavity exhibits an antibunching effect.
基金Project supported by the Excellent Youth Talent Support Program of Universities in Anhui Province,China(Grant No.GXYQZD2019021)the Major Research Project of Anhui Provincial Department of Education,China(Grant No.KJ2017ZD05)the National Natural Science Foundation of China(Grant Nos.61503002 and 61973199).
文摘Passive filtering of neural networks with time-invariant delay and quantized output is considered.A criterion on the passivity of a filtering error system is proposed by means of the Lyapunov-Krasovskii functional and the Bessel-Legendre inequality.Based on the criterion,a design approach for desired passive filters is developed in terms of the feasible solution of a set of linear matrix inequalities.Then,analyses and syntheses are extended to the time-variant delay situation using the reciprocally convex combination inequality.Finally,a numerical example with simulations is used to illustrate the applicability and reduced conservatism of the present passive filter design approaches.
基金Supported by the Natural Science Foundation of the Education Department of Hunan Province under Grant No 05C696.
文摘We present a scheme for generating four pairs of two-atom Einstein Podolsky-Rosen （EPR） states using the simultaneous interaction of the two atoms with a single-mode cavity field under a large detuning condition. The influence of cavity dissipation on the prepared EPR states is investigated by means of the superoperator method and the state fidelity. It is shown that some kinds of the prepared EPR states are robust against cavity dissipation and the intensity of the field, and maintain their entanglement invariance, and the others are fragile and completely destroyed by the action of cavity dissipation and the intensity of the field in the long-time limit. Decoherence time of the fragile entangled states is extremely small for a typical cavity-QED experimental data.
基金The project supported by the Funds for Major Basic Research Project of Sichuan Province under Grant No. 02GY029-188, and the Natural Science Foundation of the Committee of Education of Sichuan Province under Grant No. 2003 A078,.
文摘We theoretically study the properties of the ground state of the parallel-coupled double quantum dots embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the persistent current depends sensitively on both the parity of this system and the size of the ring. In the strong coupling regime, the giant sharp current peak appears, at the same time, the parity dependence of the persistent current disappears. These imply that in the strong coupling regime, there exists giant Kondo resonance and the two dots can be coupled coherently. Thus this system might be a candidate for future device applications.
基金supported by the National Natural Science Foundation of China (Grant No 10374007)the Natural Science Foundation of Hunan Province (Grant No 06jj50014)+1 种基金the Natural Science Foundation of the Education Department of Hunan Province, China(Grant No 05C696)the Young Core Teachers Foundation of Hunan Provincial Education Department, China
文摘Quantum entanglement and nonlocality properties of a family of two-mode Gaussian pure states have been investigated. The results show that the entanglement of these states is determined by both the two-mode squeezing parameter and the difference of the two single-mode squeezing parameters. For the same two-mode squeezing parameter, these states show larger entanglement than the usual two-mode squeezed vacuum state. The violation of Bell inequality depends strongly on all the squeezing parameters of these states and disappears completely in the limit of large squeezing. In particular, these states can exhibit much stronger violation of local realism than two-mode squeezed vacuum state in the range of experimentally available squeezing values.
文摘By extracting the control plane from the data plane, SDN en?ables unprecedented flexibility for future network architec?tures and quickly changes the landscape of the networking industry. Although the maturity of commonly accepted SDN security practices is the key to the proliferation of cloud DCN, SDN security research is still in its infancy. This pa?per gives a top?down survey of the approaches in this area, discussing security challenges and opportunities of software?defined datacenter networking for cloud computing. It lever?ages the well?known confidentiality?integrity?availability (CIA) matrix and protection?detection?reaction (PDR) model to give an overview of current security threats and security mea?sures. It also discusses promising research directions in this field.
基金Supported by the Funds for Major Basic Research Project of Sichuan Province under Grant No 02GY029-188, and the Natural Science Foundation of the Committee of Education of Sichuan Province under Grant No 2003 A078.
文摘We theoretically investigate the Kondo effect of a three-terminal transport quantum dot （QD） embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the Kondo effect depends sensitively oil the parity and size of the ring; the Kondo screening cloud can be tuned by tuning the coupling strength of the reservoir-dot. Thus this model might be a candidate for future device applications.
基金Supported by the Open Subject for Computer Network and Information Security Key Laboratory of Ministry of Education of China(20040108)
文摘This paper constructs the probability model of Gunther generator at first, and the finite dimension union distribution of the output sequence is presented. The result shows that the output sequence is an independent and uniformly distributed 0,1 random variable sequence. It gives the theoretical foundation about why Gunther generator can avoid the statistic weakness of the output sequence of stop-and-go generator, and analyzes the coincidence between output sequence and input sequences of Gunther generator. The conclusions of this paper would offer theoretical references for designers and analyzers of clock-controlled generators.
文摘Based on a new adaptive Particle Swarm Optimization algorithm with dynamically changing inertia weight (DAPSO), It is used to optimize parameters in PID controller. Compared to conventional PID methods, the simulation shows that this new method makes the optimization perfectly and convergence quickly.
