ISSN 
2013 Vol. 42, No. 5
2013, 42(5): 642-647.
doi: 10.3969/j.issn.1001-0548.2013.05.001
Abstract:
Memristor is a nonlinear circuit element which has property of memory and the similar synapse characteristic. In this paper, a memristive neural network based on STDP learning rule is proposed and used in the binary image overlay and the storage and output of gray and color images. Firstly, the memristor is used as the synapse, and the specific shape action potentials realizing STDP learning rules are demonstrated. Secondly, 4×4 memristive crossbar array neural networks are realized. And then the binary image overlay is obtained by the neural network of 16×16 memristive crossbar array neural networks. Finally, the storage and output of gray and color images are achieved by the N×N memristive neural network. The feasibility of the proposed method is proved by MATLAB simulation experiments. This neural network has more bionic feasibility, which could be applied to solve the complex problems in pattern recognition and artificial intelligence.
Memristor is a nonlinear circuit element which has property of memory and the similar synapse characteristic. In this paper, a memristive neural network based on STDP learning rule is proposed and used in the binary image overlay and the storage and output of gray and color images. Firstly, the memristor is used as the synapse, and the specific shape action potentials realizing STDP learning rules are demonstrated. Secondly, 4×4 memristive crossbar array neural networks are realized. And then the binary image overlay is obtained by the neural network of 16×16 memristive crossbar array neural networks. Finally, the storage and output of gray and color images are achieved by the N×N memristive neural network. The feasibility of the proposed method is proved by MATLAB simulation experiments. This neural network has more bionic feasibility, which could be applied to solve the complex problems in pattern recognition and artificial intelligence.
2013, 42(5): 648-655.
doi: 10.3969/j.issn.1001-0548.2013.05.002
Abstract:
Based on the system model language and high level architecture, a new approach of openended collaborative modeling and simulating is proposed for virtual prototype of complex systems. The new approach has the advantage of multidiscipline models integration and co-simulation in VPCS. In this approach, VPCS is divided into top model, federation model, and field component model. The scheduling mechanism of VPCS is analyzed. A virtual prototype of the flight control system of an unmanned aerial vehicle is carried out with the proposed approach. The simulation results demonstrate that the new approach can be effectively and efficiently used for modeling and simulation of multi-level, multi-granularity and multi-field VPCS.
Based on the system model language and high level architecture, a new approach of openended collaborative modeling and simulating is proposed for virtual prototype of complex systems. The new approach has the advantage of multidiscipline models integration and co-simulation in VPCS. In this approach, VPCS is divided into top model, federation model, and field component model. The scheduling mechanism of VPCS is analyzed. A virtual prototype of the flight control system of an unmanned aerial vehicle is carried out with the proposed approach. The simulation results demonstrate that the new approach can be effectively and efficiently used for modeling and simulation of multi-level, multi-granularity and multi-field VPCS.
2013, 42(5): 656-660.
doi: 10.3969/j.issn.1001-0548.2013.05.003
Abstract:
In conventional digital channelized structure, aside from rabbit-ear effect, there is no simple way to reconstruct the wideband cross-channel signal without distortion. Based on the improved algorithm of signal matched-phase, a wideband signal interception method is presented, where the sub-channels can be seamlessly combined. The method uses signal matched-phase to solve frequency ambiguity in the case of multi-channel undersampled signals. It can reconstruct the wideband cross-channel signal with neither distortion nor rabbit-ear effect. The simulation results show the effectiveness of the presented method.
In conventional digital channelized structure, aside from rabbit-ear effect, there is no simple way to reconstruct the wideband cross-channel signal without distortion. Based on the improved algorithm of signal matched-phase, a wideband signal interception method is presented, where the sub-channels can be seamlessly combined. The method uses signal matched-phase to solve frequency ambiguity in the case of multi-channel undersampled signals. It can reconstruct the wideband cross-channel signal with neither distortion nor rabbit-ear effect. The simulation results show the effectiveness of the presented method.
2013, 42(5): 661-666.
doi: 10.3969/j.issn.1001-0548.2013.05.004
Abstract:
A transmit mode switching (TMS) assisted adaptive spatial modulation (SM) scheme is proposed for multiple-input multiple-output (MIMO) transmission systems. The proposed scheme yields a performance bound with the aid of the nearest neighbor approximation. At a predefined spectral efficiency and transmit power target, the proposed scheme is capable of selecting the appropriate SM mode to minimize the conditioned pairwise error probability. Moreover, a simplified calculation method utilizing the special information transmission method of SM is proposed for mode selection. Simulation results show that the proposed scheme exhibits a better bit error ratio (BER) performance at low complexity cost compared with the conventional SM scheme, especially for the correlated MIMO channels.
A transmit mode switching (TMS) assisted adaptive spatial modulation (SM) scheme is proposed for multiple-input multiple-output (MIMO) transmission systems. The proposed scheme yields a performance bound with the aid of the nearest neighbor approximation. At a predefined spectral efficiency and transmit power target, the proposed scheme is capable of selecting the appropriate SM mode to minimize the conditioned pairwise error probability. Moreover, a simplified calculation method utilizing the special information transmission method of SM is proposed for mode selection. Simulation results show that the proposed scheme exhibits a better bit error ratio (BER) performance at low complexity cost compared with the conventional SM scheme, especially for the correlated MIMO channels.
2013, 42(5): 667-671,733.
doi: 10.3969/j.issn.1001-0548.2013.05.005
Abstract:
The main limitation of Orthogonal Frequency Division Multiplexing (OFDM)-based transmission systems is the high Peak-to-Average Power Ratio (PAPR) of the transmitted signals. This paper proposes a residue number system (RNS) based OFDM transmission method. This method can achieve lossless PAPR reduction by using the features of RNS to control dynamic range of the transmitted signals and to avoid nonlinear distortion. Numerical results show that the proposed method offers PAPR performance improvement at least 5 dB and takes less transmission bandwidth when the SNR of OFDM is above 0 dB, compared with the original OFDM.
The main limitation of Orthogonal Frequency Division Multiplexing (OFDM)-based transmission systems is the high Peak-to-Average Power Ratio (PAPR) of the transmitted signals. This paper proposes a residue number system (RNS) based OFDM transmission method. This method can achieve lossless PAPR reduction by using the features of RNS to control dynamic range of the transmitted signals and to avoid nonlinear distortion. Numerical results show that the proposed method offers PAPR performance improvement at least 5 dB and takes less transmission bandwidth when the SNR of OFDM is above 0 dB, compared with the original OFDM.
2013, 42(5): 672-677.
doi: 10.3969/j.issn.1001-0548.2013.05.006
Abstract:
In this paper, a theoretical model is developed to evaluate the data transmission performance of RLNC-based Epidemic routing in DTNs. This model can trace the data transmission process under transmission bandwidth limitation and provides an insight about the characters of RLNC-based data transmission in DTNs. The data transmission delay of RLNC-based routing protocol is compared with that of conventional routing protocol. The results demonstrate the significant performance improvement for data transmission in DTNs brought by RLNC. The proposed model provides a general tool for performance evaluation and useful guidelines for designing RLNC based routing protocols in DTNs.
In this paper, a theoretical model is developed to evaluate the data transmission performance of RLNC-based Epidemic routing in DTNs. This model can trace the data transmission process under transmission bandwidth limitation and provides an insight about the characters of RLNC-based data transmission in DTNs. The data transmission delay of RLNC-based routing protocol is compared with that of conventional routing protocol. The results demonstrate the significant performance improvement for data transmission in DTNs brought by RLNC. The proposed model provides a general tool for performance evaluation and useful guidelines for designing RLNC based routing protocols in DTNs.
2013, 42(5): 678-683.
doi: 10.3969/j.issn.1001-0548.2013.05.007
Abstract:
In order to study the influence of electromagnetic (EM) transients on the structural design of test breeder module (TBM), two plasma major disruptions in ITER and the physical environment of Chinese solid breeder TBM for EM field analysis are simulated by ANSYS finite element software. The eddy currents induced by EM transients and the trend of Lorentz forces caused by the interactions of magnetic field and the eddy currents are evaluated. Meanwhile, the structure stress, displacement of deformation, and the Joule heating effect caused by eddy currents on TBM are obtained by coupling calculation of multi-physical field. The results show that the maximum equivalent stresses and the temperature rises produced by the linear and exponent disruption are satisfied with the requirements of safety design. Moreover, the sensitivity analysis indicates that the maximum equivalent stress can be reduced by changing the length of cartridge, which provides reference for safety design of TBM.
In order to study the influence of electromagnetic (EM) transients on the structural design of test breeder module (TBM), two plasma major disruptions in ITER and the physical environment of Chinese solid breeder TBM for EM field analysis are simulated by ANSYS finite element software. The eddy currents induced by EM transients and the trend of Lorentz forces caused by the interactions of magnetic field and the eddy currents are evaluated. Meanwhile, the structure stress, displacement of deformation, and the Joule heating effect caused by eddy currents on TBM are obtained by coupling calculation of multi-physical field. The results show that the maximum equivalent stresses and the temperature rises produced by the linear and exponent disruption are satisfied with the requirements of safety design. Moreover, the sensitivity analysis indicates that the maximum equivalent stress can be reduced by changing the length of cartridge, which provides reference for safety design of TBM.
2013, 42(5): 684-687,693.
doi: 10.3969/j.issn.1001-0548.2013.05.008
Abstract:
In this paper, a novel structure of waveguide-to-mircostrip transition is proposed. This structure is based on coaxial probe. It has the advantages of compact, wide band, and good sealing. It offers different polarization directions which meets the need of engineering applications. The output port of the waveguide can be rotated at any angle around the coaxial probe. It provides more flexible design plans for radio frequency (RF) system engineers. The comparison of the advanced design system circuit simulation results and CST Microwave studio field simulate results proves that the circuits extracted is corrected. A back-to-back transition is designed, fabricated and measured. The insertion loss and return loss of the back-to-back transition are respectively below 2.28 dB and above 7.8 dB from 28.8 GHz to 40 GHz.
In this paper, a novel structure of waveguide-to-mircostrip transition is proposed. This structure is based on coaxial probe. It has the advantages of compact, wide band, and good sealing. It offers different polarization directions which meets the need of engineering applications. The output port of the waveguide can be rotated at any angle around the coaxial probe. It provides more flexible design plans for radio frequency (RF) system engineers. The comparison of the advanced design system circuit simulation results and CST Microwave studio field simulate results proves that the circuits extracted is corrected. A back-to-back transition is designed, fabricated and measured. The insertion loss and return loss of the back-to-back transition are respectively below 2.28 dB and above 7.8 dB from 28.8 GHz to 40 GHz.
2013, 42(5): 688-693.
doi: 10.3969/j.issn.1001-0548.2013.05.009
Abstract:
The particle-in-cell simulations of a Ka-band coupled-cavity traveling-wave tube (CCTWT) were performed to investigate the nonlinear interaction of the tube. The interaction circuit employs the double staggered ladder line coupled-cavity slow-wave structure. Combined with the design of well-matched high frequency coupling system, a 3-D circuit model based on CPI's Ka-band CCTWT was constructed. The particle-in-cell simulation results show that the tube can produce saturated average output power over 550 watts with greater than 600 MHz instantaneous bandwidth ranging from 28.3 GHz to 30 GHz when we adopt the similar parameters as CPI's Ka-band CCTWT, such as beam voltage, beam current and the slow-wave structure dispersion characteristics. The corresponding saturated gain and beam efficiency can reach over 33 dB and 8.39%, respectively. These results are in good agreement with the experimentally measured ones of the CPI's Ka-band CCTWT, which suggest that our design scheme is feasible and the CST PIC solver can accurately predict the performance of the CCTWT.
The particle-in-cell simulations of a Ka-band coupled-cavity traveling-wave tube (CCTWT) were performed to investigate the nonlinear interaction of the tube. The interaction circuit employs the double staggered ladder line coupled-cavity slow-wave structure. Combined with the design of well-matched high frequency coupling system, a 3-D circuit model based on CPI's Ka-band CCTWT was constructed. The particle-in-cell simulation results show that the tube can produce saturated average output power over 550 watts with greater than 600 MHz instantaneous bandwidth ranging from 28.3 GHz to 30 GHz when we adopt the similar parameters as CPI's Ka-band CCTWT, such as beam voltage, beam current and the slow-wave structure dispersion characteristics. The corresponding saturated gain and beam efficiency can reach over 33 dB and 8.39%, respectively. These results are in good agreement with the experimentally measured ones of the CPI's Ka-band CCTWT, which suggest that our design scheme is feasible and the CST PIC solver can accurately predict the performance of the CCTWT.
2013, 42(5): 694-699.
doi: 10.3969/j.issn.1001-0548.2013.05.010
Abstract:
The the characteristics of instance output power of photovoltaic inverters is analyzed under unbalanced grid faults and the power control algorithm of photovoltaic generation is put forward based on the derivation of total harmonic distortion of instruction current. The optimal parameters model of photovoltaic generation is then established with minimum integrated fluctuation amplitude of the active and reactive power as a goal when the restriction of output current harmonic distortion of photovoltaic inverters is taken into account. Finally, the overall model of photovoltaic generation system based on deadbeat current tracking is realized and the feasibility of proposed control strategy is verified with PSCAD/EMTDC simulation software.
The the characteristics of instance output power of photovoltaic inverters is analyzed under unbalanced grid faults and the power control algorithm of photovoltaic generation is put forward based on the derivation of total harmonic distortion of instruction current. The optimal parameters model of photovoltaic generation is then established with minimum integrated fluctuation amplitude of the active and reactive power as a goal when the restriction of output current harmonic distortion of photovoltaic inverters is taken into account. Finally, the overall model of photovoltaic generation system based on deadbeat current tracking is realized and the feasibility of proposed control strategy is verified with PSCAD/EMTDC simulation software.
2013, 42(5): 700-704.
doi: 10.3969/j.issn.1001-0548.2013.05.011
Abstract:
The paper proposes a method based on maximum hybrid entropy (MHE) to assess the uncertainty of equipment failure event caused by voltage sag. By considering the data characteristics of the tested samples, the combined uncertainty is decomposed into a random, a fuzzy, and a cross uncertainty. As a case study, PC is tested and assessed when it is in full speed, no-load and normal operation states. During voltage sags, PC is in different result states, such as completely crash, operating error, or false crash. The proposed method is applied to assess the failure rate and compared with existing probability methods and fuzzy methods. The results show that this method overcomes the disadvantages of over-estimating or low-estimating problem and it is more accurate in accord with the engineering practice.
The paper proposes a method based on maximum hybrid entropy (MHE) to assess the uncertainty of equipment failure event caused by voltage sag. By considering the data characteristics of the tested samples, the combined uncertainty is decomposed into a random, a fuzzy, and a cross uncertainty. As a case study, PC is tested and assessed when it is in full speed, no-load and normal operation states. During voltage sags, PC is in different result states, such as completely crash, operating error, or false crash. The proposed method is applied to assess the failure rate and compared with existing probability methods and fuzzy methods. The results show that this method overcomes the disadvantages of over-estimating or low-estimating problem and it is more accurate in accord with the engineering practice.
2013, 42(5): 705-710.
doi: 10.3969/j.issn.1001-0548.2013.05.012
Abstract:
A Boost power factor correction (PFC) converter operating in pseudo continuous conduction mode (PCCM) is analyzed and side-by-side voltage and current control loops is proposed. In order to extend the load power range of the conventional Boost PFC converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), a control strategy to adjust the reference current with respect to the load is designed. The input current and PF expression of the tri-state PCCM Boost PFC converter is also derived. To improve the input power factor (PF) of the tri-state PCCM Boost PFC converter with sinusoidal reference current control strategy over whole input voltage range, the non-sinusoidal reference current control strategy is proposed. Besides, the frequency domain analysis based on small-signal mode is given. Finally, the tri-state PCCM Boost PFC converter prototype is built and the experimental results verify the analysis results.
A Boost power factor correction (PFC) converter operating in pseudo continuous conduction mode (PCCM) is analyzed and side-by-side voltage and current control loops is proposed. In order to extend the load power range of the conventional Boost PFC converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), a control strategy to adjust the reference current with respect to the load is designed. The input current and PF expression of the tri-state PCCM Boost PFC converter is also derived. To improve the input power factor (PF) of the tri-state PCCM Boost PFC converter with sinusoidal reference current control strategy over whole input voltage range, the non-sinusoidal reference current control strategy is proposed. Besides, the frequency domain analysis based on small-signal mode is given. Finally, the tri-state PCCM Boost PFC converter prototype is built and the experimental results verify the analysis results.
2013, 42(5): 711-716.
doi: 10.3969/j.issn.1001-0548.2013.05.013
Abstract:
Because ordinary ADV212 controllers of compression scheme based on ADV212 cannot satisfy the demands of space camera, a high performance ADV212 controller for space camera is proposed in this paper. The working principle of ADV212 is first analyzed and then a working mechanism of custom-specific mode is presented. In the custom-specific mode, the frame is constructed by using the ping-pong operation of SDRAM and an ADV212 is applied to compress five-channel CCD data by pipelining. The interface among CCD, ADV212 and SDRAM is managed by interrupt handling strategy. Moreover, the three parameters which affect the quality of image compression are analyzed. The verification experiments to ADV212 compression system show that compression system works fast and stably. The time needed in compressing a frame image is only 7.68 ms, all PSNRs are more than 30 dB in the compression ratio of 2:1 to 32:1, and the average PSNR is increased by 2.49 dB in the lossy compression mode when the compression ratio is 1 bpp. The performances of the proposed controller effectively meet the requirement of applications of the large field of view TDICCD space camera.
Because ordinary ADV212 controllers of compression scheme based on ADV212 cannot satisfy the demands of space camera, a high performance ADV212 controller for space camera is proposed in this paper. The working principle of ADV212 is first analyzed and then a working mechanism of custom-specific mode is presented. In the custom-specific mode, the frame is constructed by using the ping-pong operation of SDRAM and an ADV212 is applied to compress five-channel CCD data by pipelining. The interface among CCD, ADV212 and SDRAM is managed by interrupt handling strategy. Moreover, the three parameters which affect the quality of image compression are analyzed. The verification experiments to ADV212 compression system show that compression system works fast and stably. The time needed in compressing a frame image is only 7.68 ms, all PSNRs are more than 30 dB in the compression ratio of 2:1 to 32:1, and the average PSNR is increased by 2.49 dB in the lossy compression mode when the compression ratio is 1 bpp. The performances of the proposed controller effectively meet the requirement of applications of the large field of view TDICCD space camera.
2013, 42(5): 717-722.
doi: 10.3969/j.issn.1001-0548.2013.05.014
Abstract:
A novel analysis method for the fuzzy impulsive control of general chaotic systems is presented by using the time-dependent Lyapunov function-based technique. Compared with the time-independent Lyapunov function method, the proposed method can make full use of the information about the impulsive intervals and provides less conservative results. Being different from the existing results, the derived condition for global exponential stability of the system under consideration depends both on the upper bound and the lower bound of the impulsive intervals. This condition is expressed in terms of linear matrix inequalities (LMIs). By solving a set of LMIs, a fuzzy impulsive state feedback controller can easily be obtained. Finally, the proposed impulsive control scheme is applied to the stabilization of the hyperchaotic Lü system. The simulation results demonstrate the effectiveness of the developed method.
A novel analysis method for the fuzzy impulsive control of general chaotic systems is presented by using the time-dependent Lyapunov function-based technique. Compared with the time-independent Lyapunov function method, the proposed method can make full use of the information about the impulsive intervals and provides less conservative results. Being different from the existing results, the derived condition for global exponential stability of the system under consideration depends both on the upper bound and the lower bound of the impulsive intervals. This condition is expressed in terms of linear matrix inequalities (LMIs). By solving a set of LMIs, a fuzzy impulsive state feedback controller can easily be obtained. Finally, the proposed impulsive control scheme is applied to the stabilization of the hyperchaotic Lü system. The simulation results demonstrate the effectiveness of the developed method.
2013, 42(5): 723-727.
doi: 10.3969/j.issn.1001-0548.2013.05.015
Abstract:
A cooperative multi-task assignment problem (CMPAT) model is designed for battlefield environment of multi-objective, multi-task and limited capacity of unmanned aerial vehicle (UAV). According to the task sequence constraint, the cooperative task constraint, and the UAV capacity constraint in the CMPAT model, the chromosome coding method based on task sequence and the cross and disturbance operators based on same category tasks changing are proposed. With the feature of global searching optimal solution of genetic algorithms, this algorithm can optimize the cooperative multi-task assignment of UAVs cluster. Simulation shows that the proposed algorithm can achieve more optimized solution of cooperative multi-task assignment.
A cooperative multi-task assignment problem (CMPAT) model is designed for battlefield environment of multi-objective, multi-task and limited capacity of unmanned aerial vehicle (UAV). According to the task sequence constraint, the cooperative task constraint, and the UAV capacity constraint in the CMPAT model, the chromosome coding method based on task sequence and the cross and disturbance operators based on same category tasks changing are proposed. With the feature of global searching optimal solution of genetic algorithms, this algorithm can optimize the cooperative multi-task assignment of UAVs cluster. Simulation shows that the proposed algorithm can achieve more optimized solution of cooperative multi-task assignment.
2013, 42(5): 728-733.
doi: 10.3969/j.issn.1001-0548.2013.05.016
Abstract:
Nowadays, researches on information security mainly focus on practical technologies, and many of them, such as quantum cryptography, intrusion detection, and disaster recovery, have been highly developed and widely used. However, from the theoretical perspective, there is still a lack of systematical theory which can dominate the operation and guide the development of the information security system from a certain level. In this paper, information security system is researched from a new perspective based on general system theory for the purpose of providing a new way to study information security system. Analytic hierarchy process is adopted to analyze the influencing factors of information security system and relationships among the factors themselves. Then, the interaction among some of the factors is studied through a model of differential equations. As the results show, the model in this paper reflects the inner changes of information security system to a certain extent, and plays a guiding role in the development of information security system.
Nowadays, researches on information security mainly focus on practical technologies, and many of them, such as quantum cryptography, intrusion detection, and disaster recovery, have been highly developed and widely used. However, from the theoretical perspective, there is still a lack of systematical theory which can dominate the operation and guide the development of the information security system from a certain level. In this paper, information security system is researched from a new perspective based on general system theory for the purpose of providing a new way to study information security system. Analytic hierarchy process is adopted to analyze the influencing factors of information security system and relationships among the factors themselves. Then, the interaction among some of the factors is studied through a model of differential equations. As the results show, the model in this paper reflects the inner changes of information security system to a certain extent, and plays a guiding role in the development of information security system.
2013, 42(5): 734-739.
doi: 10.3969/j.issn.1001-0548.2013.05.017
Abstract:
To address the problem that the sparse indexing can not deduplicate the backup load based on small files effectively, a min-feature sampling algorithm based on the Broder's extension theorem is proposed. In addition, a deduplication method for multiple backup loads, which is on the basis of the min-feature sampling algorithm, is presented. This method only maintains a very small subset of the full index in the RAM by sampling the backup load, and the cost of disk accesses is amortized by loading the chunk IDs in batches. As a result, the throughput of the method is improved effectively. The experimental results indicate that the compression ratio of the method on the mixed backup loads is 2.04 times of the sparse indexing, and its throughput is almost equal to the sparse indexing. This method is applicable to the high-performance deduplication systems which need to process backup loads of multiple types.
To address the problem that the sparse indexing can not deduplicate the backup load based on small files effectively, a min-feature sampling algorithm based on the Broder's extension theorem is proposed. In addition, a deduplication method for multiple backup loads, which is on the basis of the min-feature sampling algorithm, is presented. This method only maintains a very small subset of the full index in the RAM by sampling the backup load, and the cost of disk accesses is amortized by loading the chunk IDs in batches. As a result, the throughput of the method is improved effectively. The experimental results indicate that the compression ratio of the method on the mixed backup loads is 2.04 times of the sparse indexing, and its throughput is almost equal to the sparse indexing. This method is applicable to the high-performance deduplication systems which need to process backup loads of multiple types.
2013, 42(5): 740-744.
doi: 10.3969/j.issn.1001-0548.2013.05.018
Abstract:
An improved pulse coupled neural network (PCNN) model is proposed to solve combination optimization problem with help of PCNN auto-wave characteristic. Based on Tri-state cascading pulse coupled neural network (TCPCNN), a preventive feedback method by using the triangle inequality theorem is introduced. In the process of searching solutions, all solutions are judged by the triangle inequality theorem and solutions of poor quality are removed. Therefore, the solution space complexity of combinatorial optimization problems decreases and the efficiency and accuracy are improved. This algorithm is applied to the shor test path (SP) and the traveling salesman problem (TSP) simulations. The results show that the proposed algorithm can effectively reduce space complexity and further improve the searching speed.
An improved pulse coupled neural network (PCNN) model is proposed to solve combination optimization problem with help of PCNN auto-wave characteristic. Based on Tri-state cascading pulse coupled neural network (TCPCNN), a preventive feedback method by using the triangle inequality theorem is introduced. In the process of searching solutions, all solutions are judged by the triangle inequality theorem and solutions of poor quality are removed. Therefore, the solution space complexity of combinatorial optimization problems decreases and the efficiency and accuracy are improved. This algorithm is applied to the shor test path (SP) and the traveling salesman problem (TSP) simulations. The results show that the proposed algorithm can effectively reduce space complexity and further improve the searching speed.
2013, 42(5): 745-748,768.
doi: 10.3969/j.issn.1001-0548.2013.05.019
Abstract:
A new policy conflict detection method is proposed based on model checking. In this method, the model of system is specified with formal description language, the properties of system depending on different types of policy conflicts is represented with temporal logic, and the violations of properties is detected by using NuSMV model checker, which can provide the counterexample and trace it back to the policy conflict point. The result shows that the method can improve the efficiency of policy conflict detection.
A new policy conflict detection method is proposed based on model checking. In this method, the model of system is specified with formal description language, the properties of system depending on different types of policy conflicts is represented with temporal logic, and the violations of properties is detected by using NuSMV model checker, which can provide the counterexample and trace it back to the policy conflict point. The result shows that the method can improve the efficiency of policy conflict detection.
2013, 42(5): 749-752.
doi: 10.3969/j.issn.1001-0548.2013.05.020
Abstract:
In order to solve the switchover from a content management information system based on role-based access control (RBAC) model to a SOA architecture, the access control part needs to turn into the attribute-based access control (ABAC) model more suitable for distributed architecture. This paper comparatively studies two authorization models of both RBAC model and ABAC model, and analyzes how to turn existing information systems from the RBAC model into ABAC model. The result presented in this paper indicates that the smooth transition from RBAC model to ABAC model can be achieved, rather than demolishing and reconstructing.
In order to solve the switchover from a content management information system based on role-based access control (RBAC) model to a SOA architecture, the access control part needs to turn into the attribute-based access control (ABAC) model more suitable for distributed architecture. This paper comparatively studies two authorization models of both RBAC model and ABAC model, and analyzes how to turn existing information systems from the RBAC model into ABAC model. The result presented in this paper indicates that the smooth transition from RBAC model to ABAC model can be achieved, rather than demolishing and reconstructing.
2013, 42(5): 753-756.
doi: 10.3969/j.issn.1001-0548.2013.05.021
Abstract:
The paper proposes a mobility handoff scheme for vehicular networks. In this scheme, a mobile node is uniquely identified by its home IPv6 address. In addition, this scheme uses an advanced mobility handoff mechanism. The mobility handoff in the network layer is performed before the one in the link layer is done. Therefore, the AP can forward the data destined for the onboard unit to the onboard unit. Therefore, the advanced mobility handoff mechanism reduces the packet loss rate, shortens the mobility handoff delay, and ensures the communication continuity. The performance parameters of this scheme is analyzed and compared, and the results show that the mobility handoff cost of this scheme is smaller and the mobility handoff delay is shorter.
The paper proposes a mobility handoff scheme for vehicular networks. In this scheme, a mobile node is uniquely identified by its home IPv6 address. In addition, this scheme uses an advanced mobility handoff mechanism. The mobility handoff in the network layer is performed before the one in the link layer is done. Therefore, the AP can forward the data destined for the onboard unit to the onboard unit. Therefore, the advanced mobility handoff mechanism reduces the packet loss rate, shortens the mobility handoff delay, and ensures the communication continuity. The performance parameters of this scheme is analyzed and compared, and the results show that the mobility handoff cost of this scheme is smaller and the mobility handoff delay is shorter.
2013, 42(5): 757-762.
doi: 10.3969/j.issn.1001-0548.2013.05.022
Abstract:
The traditional address-based addressing scheme cannot satisfy the addressing requirement of large-scale and business-centric wireless sensor networks (WSN). To solve this problem, a new hierarchical structure applicable to the large-scale heterogeneous WSN is proposed. Based on the structure, a label-based addressing (LBA) scheme is proposed as well. The proposed scheme different business types into the lables and marks the operated data. By creating a mapping between labels and node IP addresses, a user is able to query any business data through its label. The simulation demonstrates that LBA scheme is outperforms the traditional address-based and other content-based addressing schemes in terms of data request response time and packet delivery.
The traditional address-based addressing scheme cannot satisfy the addressing requirement of large-scale and business-centric wireless sensor networks (WSN). To solve this problem, a new hierarchical structure applicable to the large-scale heterogeneous WSN is proposed. Based on the structure, a label-based addressing (LBA) scheme is proposed as well. The proposed scheme different business types into the lables and marks the operated data. By creating a mapping between labels and node IP addresses, a user is able to query any business data through its label. The simulation demonstrates that LBA scheme is outperforms the traditional address-based and other content-based addressing schemes in terms of data request response time and packet delivery.
2013, 42(5): 763-768.
doi: 10.3969/j.issn.1001-0548.2013.05.023
Abstract:
Base on collaboration model of optimal search theory in discrete spaces, an energy balancing collaboration model and its solution algorithm in wireless sensor networks are proposed in this paper by taking all the following factors into consideration: the costs and benefits of node to forward data, energy consumption, and the behavior of adjacent nodes in the past. The objective of the algorithm to balance the energy consumption and maximize the network lifetime. An energy factor and number of packets transmitted are presented to make the energy consumption of the network tend to equilibrium and maximize the network lifetime. A numerical example illustrates the validation of the proposed collaboration model and policy.
Base on collaboration model of optimal search theory in discrete spaces, an energy balancing collaboration model and its solution algorithm in wireless sensor networks are proposed in this paper by taking all the following factors into consideration: the costs and benefits of node to forward data, energy consumption, and the behavior of adjacent nodes in the past. The objective of the algorithm to balance the energy consumption and maximize the network lifetime. An energy factor and number of packets transmitted are presented to make the energy consumption of the network tend to equilibrium and maximize the network lifetime. A numerical example illustrates the validation of the proposed collaboration model and policy.
2013, 42(5): 769-772.
doi: 10.3969/j.issn.1001-0548.2013.05.024
Abstract:
The biological immune system when attacked can always find the right antibodies to destroy the antigen and can maintain the diversity of antibodies. The combination of genetic and immunity in biology has been shown to be an effective approach to solving the degeneration of genetic algorithm in the late iterative optimization. According to the characteristic that the injected vaccine immune system can accomplish quickly identification the antigen, an improved immune genetic algorithm (IIGA) is proposed based on this theory for Benchmark function optimization. The results show that the IIGA can effectively prevent the algorithm degenerative during the process of optimization of the genetic algorithm, and improve the convergent speed of the algorithm.
The biological immune system when attacked can always find the right antibodies to destroy the antigen and can maintain the diversity of antibodies. The combination of genetic and immunity in biology has been shown to be an effective approach to solving the degeneration of genetic algorithm in the late iterative optimization. According to the characteristic that the injected vaccine immune system can accomplish quickly identification the antigen, an improved immune genetic algorithm (IIGA) is proposed based on this theory for Benchmark function optimization. The results show that the IIGA can effectively prevent the algorithm degenerative during the process of optimization of the genetic algorithm, and improve the convergent speed of the algorithm.
2013, 42(5): 773-777.
doi: 10.3969/j.issn.1001-0548.2013.05.025
Abstract:
The new generation Ethernet commonly refers to the Ethernet for speed to exceed 10 Gb/s. This paper first introduces research progresses in the field at home and abroad, and then constructs the layer structures model and function model of 40 and 100 Gigabit Ethernet in different transfer patterns. The parameters of the model are analyzed, including the relation between each physics sublayer and interface and the relation between different transfer patterns and every factor in the structure model. The design thought, technical schemes, and typical realization about parallel transfers are put forward, which provide technical support to the research and development of new generation Ethernet.
The new generation Ethernet commonly refers to the Ethernet for speed to exceed 10 Gb/s. This paper first introduces research progresses in the field at home and abroad, and then constructs the layer structures model and function model of 40 and 100 Gigabit Ethernet in different transfer patterns. The parameters of the model are analyzed, including the relation between each physics sublayer and interface and the relation between different transfer patterns and every factor in the structure model. The design thought, technical schemes, and typical realization about parallel transfers are put forward, which provide technical support to the research and development of new generation Ethernet.
2013, 42(5): 778-783.
doi: 10.3969/j.issn.1001-0548.2013.05.026
Abstract:
Identity-based ring signature has wide applications such as ad-hoc networks etc., since it can protect the privacy of signer and simplify the process of key management. However, most of existing schemes are constructed from bilinear pairings. In this paper, we firstly propose a new identity-based ring signature scheme based on cubic residues. Our proposed scheme is secure against existential forgery on the adaptively chosen identity and message attacks under the random oracle model assuming the hardness of factoring. Our work extends the research field of identity-based ring signature due to the new mathematical tools.
Identity-based ring signature has wide applications such as ad-hoc networks etc., since it can protect the privacy of signer and simplify the process of key management. However, most of existing schemes are constructed from bilinear pairings. In this paper, we firstly propose a new identity-based ring signature scheme based on cubic residues. Our proposed scheme is secure against existential forgery on the adaptively chosen identity and message attacks under the random oracle model assuming the hardness of factoring. Our work extends the research field of identity-based ring signature due to the new mathematical tools.
2013, 42(5): 784-786.
doi: 10.3969/j.issn.1001-0548.2013.05.027
Abstract:
In view of the AlN thin films preparation, two AlN/Al2O3(0001) growth models have been built. With the plane wave ultrasoft pseudo-potential method based on the density functional theory, the analog computation of the AlN surface absorption of α-Al2O3(0001) has been made. The analysis of the AlN surface absorption site and the structures of surface and interface finds that a 30° angle of deflection exists between AlN and the nearest surface. The stability of the chemical absorption eliminates the relaxation surface absorption of Al-O film and therefore benefits the formation of the wurtzite structure of AlN film.
In view of the AlN thin films preparation, two AlN/Al2O3(0001) growth models have been built. With the plane wave ultrasoft pseudo-potential method based on the density functional theory, the analog computation of the AlN surface absorption of α-Al2O3(0001) has been made. The analysis of the AlN surface absorption site and the structures of surface and interface finds that a 30° angle of deflection exists between AlN and the nearest surface. The stability of the chemical absorption eliminates the relaxation surface absorption of Al-O film and therefore benefits the formation of the wurtzite structure of AlN film.
2013, 42(5): 787-790.
doi: 10.3969/j.issn.1001-0548.2013.05.028
Abstract:
Finite-element modeling of printed circuit board (PCB) often very difficult due to the complexity of its structure, so an equivalent modeling method of PCB based on experimental data for dynamic property analysis is presented. In the method, the equivalent dimension is obtained from main dimension of real PCB structure, the equivalent density is calculated by the principle of mass equality, and the equivalent stiffness formula is derived based on the theory of vibration and finite element method. Additionally, the influences of joint constrain on equivalent stiffness are studied. In the end, an example shows this method is a good way and available in engineering projects.
Finite-element modeling of printed circuit board (PCB) often very difficult due to the complexity of its structure, so an equivalent modeling method of PCB based on experimental data for dynamic property analysis is presented. In the method, the equivalent dimension is obtained from main dimension of real PCB structure, the equivalent density is calculated by the principle of mass equality, and the equivalent stiffness formula is derived based on the theory of vibration and finite element method. Additionally, the influences of joint constrain on equivalent stiffness are studied. In the end, an example shows this method is a good way and available in engineering projects.
2013, 42(5): 791-793.
doi: 10.3969/j.issn.1001-0548.2013.05.029
Abstract:
Using the adaptive boosting (AdaBoost) algorithm, the traditional classifiers, i.e. the BP neural network, the support vector machine (SVM) and the linear discriminant analysis (LDA) classifier, are trained into stronger ones. Based on traditional classifiers, the function weights and data processing are first adjusted according to the mapped output of classifiers. This method could effectively decrease the dependence on data features. These trained classifiers are then used to identify a group of data elicited by motor imagery. Based on the AdaBoost algorithm, the trained classifiers can obtain higher classification accuracy than the traditional ones. These results confirm the potential valuation of AdaBoost algorithm in BCI applications.
Using the adaptive boosting (AdaBoost) algorithm, the traditional classifiers, i.e. the BP neural network, the support vector machine (SVM) and the linear discriminant analysis (LDA) classifier, are trained into stronger ones. Based on traditional classifiers, the function weights and data processing are first adjusted according to the mapped output of classifiers. This method could effectively decrease the dependence on data features. These trained classifiers are then used to identify a group of data elicited by motor imagery. Based on the AdaBoost algorithm, the trained classifiers can obtain higher classification accuracy than the traditional ones. These results confirm the potential valuation of AdaBoost algorithm in BCI applications.
2013, 42(5): 794-799.
doi: 10.3969/j.issn.1001-0548.2013.05.030
Abstract:
Because Katsevich algorithm includes the partial derivative with respect to the variable of trajectory, the analysis of structure factor and subsequent computation of reconstruction are ignored at the intersection point of two source orbits consisting of a circle and orthogonal lines, which may induce artifacts in the reconstructed image. This paper investigates the Katsevich algorithm for this geometry, determines the structure factor at the intersection point, and deduces the corresponding reconstruction formula about two source trajectories using the planar detector. As a result, an equivalence formula is achieved excluding the partial derivative with respect to the variable of trajectory and can be used to calculate the contribution of critical plane at the intersection point. In addition, a smooth transitional function is suggested to improve the discontinuity of contribution at the border of projection region defined by PI-lines. Computer simulations about Forbild phantom show a reduction of the artifacts that are found with the Katsevich algorithm and verify the validity of the proposed algorithm.
Because Katsevich algorithm includes the partial derivative with respect to the variable of trajectory, the analysis of structure factor and subsequent computation of reconstruction are ignored at the intersection point of two source orbits consisting of a circle and orthogonal lines, which may induce artifacts in the reconstructed image. This paper investigates the Katsevich algorithm for this geometry, determines the structure factor at the intersection point, and deduces the corresponding reconstruction formula about two source trajectories using the planar detector. As a result, an equivalence formula is achieved excluding the partial derivative with respect to the variable of trajectory and can be used to calculate the contribution of critical plane at the intersection point. In addition, a smooth transitional function is suggested to improve the discontinuity of contribution at the border of projection region defined by PI-lines. Computer simulations about Forbild phantom show a reduction of the artifacts that are found with the Katsevich algorithm and verify the validity of the proposed algorithm.
