ISSN 
2010 Vol. 39, No. 1
2010, 39(1): 1-5.
doi: 10.3969/j.issn.1001-0548.2010.01.001
Abstract:
By analyzing the rejection problems of interference/clutters from an array radar,a noisy blind source extraction algorithm based on linear prediction is proposed to extract the echo from array radar signals, realize the simultaneous rejection of interference and clutters and finally increase the target detection probability of radar.On basis of the realistic receiving signal model established for array radars,the performance of proposed algorithm for the echo extraction and the target detection is analyzed by the simulation.The results show that using the proposed algorithm,the effect of echo extraction is good and the correlation coefficient on average is more than 0.93.Also,the detection probability of array radar is close to 1 when the normalized Doppler frequencies of moving targets are larger than ±0.1 Hz.The feasibility and the effectiveness of the proposed algorithm are therefore confirmed.
By analyzing the rejection problems of interference/clutters from an array radar,a noisy blind source extraction algorithm based on linear prediction is proposed to extract the echo from array radar signals, realize the simultaneous rejection of interference and clutters and finally increase the target detection probability of radar.On basis of the realistic receiving signal model established for array radars,the performance of proposed algorithm for the echo extraction and the target detection is analyzed by the simulation.The results show that using the proposed algorithm,the effect of echo extraction is good and the correlation coefficient on average is more than 0.93.Also,the detection probability of array radar is close to 1 when the normalized Doppler frequencies of moving targets are larger than ±0.1 Hz.The feasibility and the effectiveness of the proposed algorithm are therefore confirmed.
2010, 39(1): 6-10.
doi: 10.3969/j.issn.1001-0548.2010.01.002
Abstract:
This paper presents a 3D SAR imaging and multi-look processing algorithm in the variation of the velocity for the forward-looking ground penetrating radar (FLGPR).By using nonstationary convolution filter,the spectrum of the refocused image can be reconstructed directly from the spectrum of backscattered signal from the target area and the 3D target image is reconstructed after the inverse Fourier transform.By estimating the incidence angle of target,the refraction correction and the multi-look processing are accomplished.The effectiveness of the approach is demonstrated with experimental data set.
This paper presents a 3D SAR imaging and multi-look processing algorithm in the variation of the velocity for the forward-looking ground penetrating radar (FLGPR).By using nonstationary convolution filter,the spectrum of the refocused image can be reconstructed directly from the spectrum of backscattered signal from the target area and the 3D target image is reconstructed after the inverse Fourier transform.By estimating the incidence angle of target,the refraction correction and the multi-look processing are accomplished.The effectiveness of the approach is demonstrated with experimental data set.
2010, 39(1): 11-15.
doi: 10.3969/j.issn.1001-0548.2010.01.003
Abstract:
An algorithm based on Gabor filters is presented to extract image texture character.The extracted features are inputted into the PCNN to segment the image.This method can achieve good segmentation result and improve the algorithm's processing speed.The experiment results show that the proposed method process faster than the traditional method using Gabor filters,meanwhile,both of them have the similar segmentation accuracy.
An algorithm based on Gabor filters is presented to extract image texture character.The extracted features are inputted into the PCNN to segment the image.This method can achieve good segmentation result and improve the algorithm's processing speed.The experiment results show that the proposed method process faster than the traditional method using Gabor filters,meanwhile,both of them have the similar segmentation accuracy.
2010, 39(1): 16-20.
doi: 10.3969/j.issn.1001-0548.2010.01.004
Abstract:
The object's echo time delay often fluctuates in ground-penetrating radar (GPR) application due to the effect of soil.Such fluctuation can hardly be amended using the traditional algorithm with constant velocity to get the optimum image.A new method for precise SAR imaging is proposed by using the lateral variable velocity F-K migration in this paper.The equivalent lateral velocity can be fast estimated by the hyperbolic signatures of the echo.Experimental results show that the proposed method is more effective than the constant velocity migration.
The object's echo time delay often fluctuates in ground-penetrating radar (GPR) application due to the effect of soil.Such fluctuation can hardly be amended using the traditional algorithm with constant velocity to get the optimum image.A new method for precise SAR imaging is proposed by using the lateral variable velocity F-K migration in this paper.The equivalent lateral velocity can be fast estimated by the hyperbolic signatures of the echo.Experimental results show that the proposed method is more effective than the constant velocity migration.
2010, 39(1): 21-24.
doi: 10.3969/j.issn.1001-0548.2010.01.005
Abstract:
Segment correlation-video integration is the most commonly used method for radar signal detection,global positioning system (GPS),and Galileo signal detection.The performance of the segment correlation-video integration method under Doppler shift is analyzed and the processing loss formula is derived. Given the maximum Doppler shift and the carrier-to-noise ratio,the optimum intermediate frequency integration time for the global navigation satellite system (GNSS) receiver is calculated and analyzed based on the minimal mean processing loss criteria.Given the carrier-to-noise ratio of 45 dB-Hz and maximum Doppler shift of 2000 Hz, the mean processing loss is reduced up to 13.5% with the proposed method.
Segment correlation-video integration is the most commonly used method for radar signal detection,global positioning system (GPS),and Galileo signal detection.The performance of the segment correlation-video integration method under Doppler shift is analyzed and the processing loss formula is derived. Given the maximum Doppler shift and the carrier-to-noise ratio,the optimum intermediate frequency integration time for the global navigation satellite system (GNSS) receiver is calculated and analyzed based on the minimal mean processing loss criteria.Given the carrier-to-noise ratio of 45 dB-Hz and maximum Doppler shift of 2000 Hz, the mean processing loss is reduced up to 13.5% with the proposed method.
2010, 39(1): 25-28.
doi: 10.3969/j.issn.1001-0548.2010.01.006
Abstract:
Optical burst switching (OBS) is one of the promising switching technologies of the all optical networks.When burst contention occurs at an intermediate switch due to limited resources,the bursts that are in contention will be dropped.In this paper,we propose an edge buffer based contention resolution (EBR) scheme, which could mitigate and resolve contention by deflecting the contending bursts to the electronic buffer of the schedule module in the edge nodes which are directly connected to core switching nodes.The simulation of EBR scheme under self-similar traffic shows that our scheme could achieve much better performance on the burst dropping rate and its simplicity makes it easy to co-exist with other contention resolution schemes.
Optical burst switching (OBS) is one of the promising switching technologies of the all optical networks.When burst contention occurs at an intermediate switch due to limited resources,the bursts that are in contention will be dropped.In this paper,we propose an edge buffer based contention resolution (EBR) scheme, which could mitigate and resolve contention by deflecting the contending bursts to the electronic buffer of the schedule module in the edge nodes which are directly connected to core switching nodes.The simulation of EBR scheme under self-similar traffic shows that our scheme could achieve much better performance on the burst dropping rate and its simplicity makes it easy to co-exist with other contention resolution schemes.
2010, 39(1): 29-32.
doi: 10.3969/j.issn.1001-0548.2010.01.007
Abstract:
When transmitting Internet protocol (IP) packets over error-prone networks,bit error can cause packet loss besides network congestion.Packet loss makes a strong impact on source recovery.For the sake of decreasing packet loss ratio,we consider the problem of error resilient decoding for internet protocol version 4 (IPv4).The correlation between fields in IP packet header is analyzed,a mathematical model for error resilient IPv4 decoding,and the error resilient decoding criterion using maximum a posterior (MAP) is deduced.Based on the decoding is constructed criterion,a novel error resilient decoding algorithm is proposed for IPv4 in segmenting form.Experimental results show that the algorithm can enhances the abilities of correcting errors significantly.
When transmitting Internet protocol (IP) packets over error-prone networks,bit error can cause packet loss besides network congestion.Packet loss makes a strong impact on source recovery.For the sake of decreasing packet loss ratio,we consider the problem of error resilient decoding for internet protocol version 4 (IPv4).The correlation between fields in IP packet header is analyzed,a mathematical model for error resilient IPv4 decoding,and the error resilient decoding criterion using maximum a posterior (MAP) is deduced.Based on the decoding is constructed criterion,a novel error resilient decoding algorithm is proposed for IPv4 in segmenting form.Experimental results show that the algorithm can enhances the abilities of correcting errors significantly.
2010, 39(1): 33-36.
doi: 10.3969/j.issn.1001-0548.2010.01.008
Abstract:
To improve the performance of IEEE 802.11 wireless local area network (LAN),this paper presents a novel contention aware adjusting mechanism combining adaptive contention window and random varying timing method.The adaptive contention window scheme can determine the contention window based on the collision status rapidly,and the dynamical varying timing method can make the node adjust the number of packets sending during the busy or idle period.The simulations show that our mechanism is able to optimize the parameters of packets sending,utilize the radio resource reasonably,and decrease the average packet delay obviously.
To improve the performance of IEEE 802.11 wireless local area network (LAN),this paper presents a novel contention aware adjusting mechanism combining adaptive contention window and random varying timing method.The adaptive contention window scheme can determine the contention window based on the collision status rapidly,and the dynamical varying timing method can make the node adjust the number of packets sending during the busy or idle period.The simulations show that our mechanism is able to optimize the parameters of packets sending,utilize the radio resource reasonably,and decrease the average packet delay obviously.
2010, 39(1): 37-40.
doi: 10.3969/j.issn.1001-0548.2010.01.009
Abstract:
Focus plane array has been widely used in real-time Passive millimeter wave (PMMW) imaging. But its antenna pattern nonhomogeneity because of feed lateral displacement results in space variance of point spread function (PSF) in PMMW image.In order to study the complicated space-variant law of PSF,an approach is proposed to generate antenna patterns of offset feeds by back propagation (BP) neural network.By analyzing the characteristics of data of antenna pattern,the structure with its input/output data formats of the BP network are discussed.Experimental results demonstrate that the antenna pattern generated by the neural network with double hidden layers exhibits a precision no less than 99.75%.
Focus plane array has been widely used in real-time Passive millimeter wave (PMMW) imaging. But its antenna pattern nonhomogeneity because of feed lateral displacement results in space variance of point spread function (PSF) in PMMW image.In order to study the complicated space-variant law of PSF,an approach is proposed to generate antenna patterns of offset feeds by back propagation (BP) neural network.By analyzing the characteristics of data of antenna pattern,the structure with its input/output data formats of the BP network are discussed.Experimental results demonstrate that the antenna pattern generated by the neural network with double hidden layers exhibits a precision no less than 99.75%.
2010, 39(1): 41-44,49.
doi: 10.3969/j.issn.1001-0548.2010.01.010
Abstract:
In hybrid automatic repeat request (HARQ) process,the failure of the first transmission is the condition of the retransmission.The distribution of the noise after combining is not zero-mean-Gaussian. Unfortunately,the assumption of zero-mean-Gaussian noise is widely used in the analysis of HARQ,as well as some similar technologies.Therefore,the estimation of the conditional error probability is smaller than the exact one.In this paper,the conditional error probability under non-zero-mean-Gaussian noise is exactly analyzed.An approximate expression of the exact conditional error probability is also presented for simplicity of application.The difference between the real error probability and estimation based on zero-mean-Gaussian noise assumption is more obvious if the number of symbols in a packet is small and the channel of retransmission is worse than that of the first transmission.
In hybrid automatic repeat request (HARQ) process,the failure of the first transmission is the condition of the retransmission.The distribution of the noise after combining is not zero-mean-Gaussian. Unfortunately,the assumption of zero-mean-Gaussian noise is widely used in the analysis of HARQ,as well as some similar technologies.Therefore,the estimation of the conditional error probability is smaller than the exact one.In this paper,the conditional error probability under non-zero-mean-Gaussian noise is exactly analyzed.An approximate expression of the exact conditional error probability is also presented for simplicity of application.The difference between the real error probability and estimation based on zero-mean-Gaussian noise assumption is more obvious if the number of symbols in a packet is small and the channel of retransmission is worse than that of the first transmission.
2010, 39(1): 45-49.
doi: 10.3969/j.issn.1001-0548.2010.01.011
Abstract:
Short delay multipath of Galileo BOC (1,1) signal can not be effectively mitigated by traditional methods.A method transforming multipath mitigation to optimum fitting is proposed.The Genetic algorthm is used in the mitigation of multipath to reduce the Galileo pseudo-range measurement error of each channel and improve positioning accuracy.The steps of the method are described,and the simulation result proves that the estimation of multipath by the method is affective.
Short delay multipath of Galileo BOC (1,1) signal can not be effectively mitigated by traditional methods.A method transforming multipath mitigation to optimum fitting is proposed.The Genetic algorthm is used in the mitigation of multipath to reduce the Galileo pseudo-range measurement error of each channel and improve positioning accuracy.The steps of the method are described,and the simulation result proves that the estimation of multipath by the method is affective.
2010, 39(1): 50-54.
doi: 10.3969/j.issn.1001-0548.2010.01.012
Abstract:
The low earth orbit (LEO) and medium earth orbit (MEO) constellation network with inter-satellite links (ISL) is a critical element in the satellite information transfer network.A 2-layer LEO/MEO constellation model with ISL is constructed.The MEO and LEO constellation networking is analyzed.The simulation system of the LEO/MEO constellation networking in the satellite information transfer network is designed.With STK simulation,the LEO/MEO constellation structure,connection/disconnection time of links between satellites,links between satellite and ground,and link transmission time delays are obtained.The topology change data of the satellite information transfer network is analyzed.The study achievements are applied into the construction of the satellite information transfer network and provide the foundation for the comprehensive performance evaluation of the satellite information transfer network.
The low earth orbit (LEO) and medium earth orbit (MEO) constellation network with inter-satellite links (ISL) is a critical element in the satellite information transfer network.A 2-layer LEO/MEO constellation model with ISL is constructed.The MEO and LEO constellation networking is analyzed.The simulation system of the LEO/MEO constellation networking in the satellite information transfer network is designed.With STK simulation,the LEO/MEO constellation structure,connection/disconnection time of links between satellites,links between satellite and ground,and link transmission time delays are obtained.The topology change data of the satellite information transfer network is analyzed.The study achievements are applied into the construction of the satellite information transfer network and provide the foundation for the comprehensive performance evaluation of the satellite information transfer network.
2010, 39(1): 55-57,79.
doi: 10.3969/j.issn.1001-0548.2010.01.013
Abstract:
A method to discriminate textiles based on terahertz time-domain spectroscopy (THz-TDS) is proposed,and some commonly used synthetic fibers are investigated.The absorption spectra of uarious synthetic fibers are measured using the THz-TDS system.The experimental results show that terylene,polyamide,and vinylon have a characteristic absorption peak at 0.98 THz,1.51 THz,and 1.16 THz in their absorption spectra, respectively,while aromatic polyamide fiber,acrylic fiber,and Tencel fiber have no characteristic peaks but differ from each other very much.The research results show that it is feasible to apply terahertz time domain spectroscopy into the identification of synthetic fibers.
A method to discriminate textiles based on terahertz time-domain spectroscopy (THz-TDS) is proposed,and some commonly used synthetic fibers are investigated.The absorption spectra of uarious synthetic fibers are measured using the THz-TDS system.The experimental results show that terylene,polyamide,and vinylon have a characteristic absorption peak at 0.98 THz,1.51 THz,and 1.16 THz in their absorption spectra, respectively,while aromatic polyamide fiber,acrylic fiber,and Tencel fiber have no characteristic peaks but differ from each other very much.The research results show that it is feasible to apply terahertz time domain spectroscopy into the identification of synthetic fibers.
2010, 39(1): 58-60.
doi: 10.3969/j.issn.1001-0548.2010.01.014
Abstract:
A millimeter wave sheet-beam extended interaction oscillator (SBEIO) operating at TM31 is studied.The dispersion characteristic and coupling impedance of the slow-wave structure are analyzed and the slow-wave structure for 8 mm SBEIO is designed with CST code.With the simulation of the PIC software,CHPIC code,when the SBEIO operates at TM31 at 2π point with the beam voltage 19kV,current 3 A,and longitudinal magnetic field 0.3 T,the operating frequency is 37.9 GHz and the output power is over 3.5 kW.The simulation results agree well with the design values.
A millimeter wave sheet-beam extended interaction oscillator (SBEIO) operating at TM31 is studied.The dispersion characteristic and coupling impedance of the slow-wave structure are analyzed and the slow-wave structure for 8 mm SBEIO is designed with CST code.With the simulation of the PIC software,CHPIC code,when the SBEIO operates at TM31 at 2π point with the beam voltage 19kV,current 3 A,and longitudinal magnetic field 0.3 T,the operating frequency is 37.9 GHz and the output power is over 3.5 kW.The simulation results agree well with the design values.
2010, 39(1): 61-64.
doi: 10.3969/j.issn.1001-0548.2010.01.015
Abstract:
Gate oxide short is one of the key issue to the reliability of integrated circuit (IC),it can result in parametric failure without any logic error.In this paper,the behavior of a CMOS NAND gate with this gate oxide shorts is investigated base on dynamic supply current (IDDT) testing in circuit level.Some appropriate test patterns are selected to simulate and analyze the dynamic supply current of the gate oxide short circuit in TSMC 0.18 μm technology without any logic fault.The simulate results demonstrate that it is possible to detect the defective devices by analyzing the IDDT on the power supply path.Compared with the voltage test,IDDT testing can detect the gate oxide shorts more effectively.
Gate oxide short is one of the key issue to the reliability of integrated circuit (IC),it can result in parametric failure without any logic error.In this paper,the behavior of a CMOS NAND gate with this gate oxide shorts is investigated base on dynamic supply current (IDDT) testing in circuit level.Some appropriate test patterns are selected to simulate and analyze the dynamic supply current of the gate oxide short circuit in TSMC 0.18 μm technology without any logic fault.The simulate results demonstrate that it is possible to detect the defective devices by analyzing the IDDT on the power supply path.Compared with the voltage test,IDDT testing can detect the gate oxide shorts more effectively.
2010, 39(1): 65-68.
doi: 10.3969/j.issn.1001-0548.2010.01.016
Abstract:
On the condition of small samples,it is difficult to achieve ARMA model parameters by only using moment estimation (ME).In this paper,a particle swarm optimization (PSO) algorithm is used to obtain optimal numeric solutions of small sample ARMA model in the sense of maximum likelihood estimation (MIE). The principle and evaluation index of PSO are discussed in detail,which is based on analyzing likelihood function of ARMA model.Actual example shows that the joint PSO optimization method used for estimating AMAR model parameters has better characteristics in comparison with other methods.At the same time,some advantages and disadvantages are expatiated and analyzed from perspectives of algorithm and likelihood function.
On the condition of small samples,it is difficult to achieve ARMA model parameters by only using moment estimation (ME).In this paper,a particle swarm optimization (PSO) algorithm is used to obtain optimal numeric solutions of small sample ARMA model in the sense of maximum likelihood estimation (MIE). The principle and evaluation index of PSO are discussed in detail,which is based on analyzing likelihood function of ARMA model.Actual example shows that the joint PSO optimization method used for estimating AMAR model parameters has better characteristics in comparison with other methods.At the same time,some advantages and disadvantages are expatiated and analyzed from perspectives of algorithm and likelihood function.
2010, 39(1): 69-73.
doi: 10.3969/j.issn.1001-0548.2010.01.017
Abstract:
On the basis of iSLIP (iterative slip) algorithm,a VOQ (virtual output queuing) based high speed switching scheduling algorithm,i-CPRR (iterative-correlatived pointer round-robin) algorithm is presented.In this algorithm,the math principle of uncontested diagonal data in bipartite graphs matching is utilized and the correlative pointer processing method is adopted.This algorithm simplifies the round-robin mode of the pointer and reduces the design difficulty.The simulation results show that the algorithm decreases the iterative times in the scheduling procedure,improves the bandwidth utilization under heavy load,reduces the time delay and the depth of VOQ queue in the switching system.It has wide application prospective in high speed switching systems.
On the basis of iSLIP (iterative slip) algorithm,a VOQ (virtual output queuing) based high speed switching scheduling algorithm,i-CPRR (iterative-correlatived pointer round-robin) algorithm is presented.In this algorithm,the math principle of uncontested diagonal data in bipartite graphs matching is utilized and the correlative pointer processing method is adopted.This algorithm simplifies the round-robin mode of the pointer and reduces the design difficulty.The simulation results show that the algorithm decreases the iterative times in the scheduling procedure,improves the bandwidth utilization under heavy load,reduces the time delay and the depth of VOQ queue in the switching system.It has wide application prospective in high speed switching systems.
2010, 39(1): 74-79.
doi: 10.3969/j.issn.1001-0548.2010.01.018
Abstract:
A new kind of Anycast communication model in mobile IPv6 networks which is built on a tree topology is proposed.The model combines Unicast technology and Multicast technology.Each mobile node in this model has only one permanent address-home address with which it can achieve the communication with clients.In addition,this model can perform IPSec which is difficult to implement in the existing mobile IP communication models.In an IPv6 simulation environment,the experimental data prove the model's effectivity,practicability and efficiency.
A new kind of Anycast communication model in mobile IPv6 networks which is built on a tree topology is proposed.The model combines Unicast technology and Multicast technology.Each mobile node in this model has only one permanent address-home address with which it can achieve the communication with clients.In addition,this model can perform IPSec which is difficult to implement in the existing mobile IP communication models.In an IPv6 simulation environment,the experimental data prove the model's effectivity,practicability and efficiency.
2010, 39(1): 80-84.
doi: 10.3969/j.issn.1001-0548.2010.01.019
Abstract:
To effectively detect unknown Windows PE viruses,a novel approach that roots in artificial immune system and uses the self-relocation module to generate antibodies is presented.The logical structure of Windows PE virus is briefly described.The dynamic evolution of self and nonself,the presentation of antigen,and the generation of antibody are proposed.The experiment results indicate that this approach not only has relatively high detection rate of unknown Windows PE virus,but also has better capability of self-adaptive and self-learning.
To effectively detect unknown Windows PE viruses,a novel approach that roots in artificial immune system and uses the self-relocation module to generate antibodies is presented.The logical structure of Windows PE virus is briefly described.The dynamic evolution of self and nonself,the presentation of antigen,and the generation of antibody are proposed.The experiment results indicate that this approach not only has relatively high detection rate of unknown Windows PE virus,but also has better capability of self-adaptive and self-learning.
2010, 39(1): 85-90.
doi: 10.3969/j.issn.1001-0548.2010.01.020
Abstract:
As a new direction in network security,the survivability of information systems is different from traditional network security.This paper presents a service self-organization method based on connection handoff. According to service processing flow,the system is divided into communication,service distribution,and service supply modules.Backup modules survivability information is send to online modules and gets the list of newest service states.When the survivability of a module is highest,the self-organization strategies are implemented using multi-handoff technology.The system possesses the merits such as transparency to users,flexibility and operability of the configuration.Experiments confirm that this method can enhance the quality of service and improve service survivability.
As a new direction in network security,the survivability of information systems is different from traditional network security.This paper presents a service self-organization method based on connection handoff. According to service processing flow,the system is divided into communication,service distribution,and service supply modules.Backup modules survivability information is send to online modules and gets the list of newest service states.When the survivability of a module is highest,the self-organization strategies are implemented using multi-handoff technology.The system possesses the merits such as transparency to users,flexibility and operability of the configuration.Experiments confirm that this method can enhance the quality of service and improve service survivability.
2010, 39(1): 91-96.
doi: 10.3969/j.issn.1001-0548.2010.01.021
Abstract:
Personalized search and vertical search are receiving more and more attention of users.User preference-based vertical search algorithm (PVSA) is proposed in this paper.By focusing on domain characteristics, PVSA uses domain topic preference vector,domain metadata weight factors,the strategy of distinguishing weights of input terms,and industry lexicon update to mine different domain preferences of different users.Experimental results show that the proposed algorithm is feasible and effective in mining users' personal preferences.
Personalized search and vertical search are receiving more and more attention of users.User preference-based vertical search algorithm (PVSA) is proposed in this paper.By focusing on domain characteristics, PVSA uses domain topic preference vector,domain metadata weight factors,the strategy of distinguishing weights of input terms,and industry lexicon update to mine different domain preferences of different users.Experimental results show that the proposed algorithm is feasible and effective in mining users' personal preferences.
2010, 39(1): 97-100,151.
doi: 10.3969/j.issn.1001-0548.2010.01.022
Abstract:
In the paper a method of man-in-the middle attack to IKEv1 is discussed and analyzed is based on the aggressive mode of IKEv1 key exchange with pre-share-key authentication.The conditions and implementing methods of the attack are obtained by analyzing the principle of the attack to IKEv1 on the mode.For implementing man-in-the middle attack,the pre-share-key is first achieved by exhaustion method with offline password of IKEv1. The theory of Diffie-Hellman (DH) man-in-the middle attack to applied to the aggressive mode of IKEv1.Because there are some offline password leaks in the mode for obtaining pre-share-key,the conclusion is that the attack would jeopardize IPsec VPN in practice.
In the paper a method of man-in-the middle attack to IKEv1 is discussed and analyzed is based on the aggressive mode of IKEv1 key exchange with pre-share-key authentication.The conditions and implementing methods of the attack are obtained by analyzing the principle of the attack to IKEv1 on the mode.For implementing man-in-the middle attack,the pre-share-key is first achieved by exhaustion method with offline password of IKEv1. The theory of Diffie-Hellman (DH) man-in-the middle attack to applied to the aggressive mode of IKEv1.Because there are some offline password leaks in the mode for obtaining pre-share-key,the conclusion is that the attack would jeopardize IPsec VPN in practice.
2010, 39(1): 101-105.
doi: 10.3969/j.issn.1001-0548.2010.01.023
Abstract:
By analyzing the original testing adequacy determination in Markov model,the strict transfer probability is defined and then testing adequacy based on strict transfer probability is advanced.Markov model is transformed to strict Markov model,and the strict transfer probability is used to calculate the differentiation of every edge.The primal transfer probability of all of accessibility discriminative transfer probability is computed for accessibility discriminative transfer set,and then the probability is obtained.Experiments declares that new method is more stabile and efficient.
By analyzing the original testing adequacy determination in Markov model,the strict transfer probability is defined and then testing adequacy based on strict transfer probability is advanced.Markov model is transformed to strict Markov model,and the strict transfer probability is used to calculate the differentiation of every edge.The primal transfer probability of all of accessibility discriminative transfer probability is computed for accessibility discriminative transfer set,and then the probability is obtained.Experiments declares that new method is more stabile and efficient.
2010, 39(1): 106-109.
doi: 10.3969/j.issn.1001-0548.2010.01.024
Abstract:
For a class of popular IP network applications,a prototype of performance-optimized communication network for virtual machines is proposed.A few virtual machines run on the top of Xen,which is high-performance virtual machine monitor and multiplexes the underlying physical host.Xen creates and manages these virtual machines.A new virtual network card is the core of the prototype.All virtual machines are interconnected by this card into a network.Compared with default model of Xen,the prototype can improve the communication performance and reduce the response time for request by 42%.
For a class of popular IP network applications,a prototype of performance-optimized communication network for virtual machines is proposed.A few virtual machines run on the top of Xen,which is high-performance virtual machine monitor and multiplexes the underlying physical host.Xen creates and manages these virtual machines.A new virtual network card is the core of the prototype.All virtual machines are interconnected by this card into a network.Compared with default model of Xen,the prototype can improve the communication performance and reduce the response time for request by 42%.
2010, 39(1): 110-113.
doi: 10.3969/j.issn.1001-0548.2010.01.025
Abstract:
Researchers' publication sequence contain some important information which can be utilized to discover the research areas trend,reflect the relative ranking of academic conferences,and indicate the hot research topics.A systematic method is proposed to discover the knowledge hidden in the publication sequences to identify the connection between different research disciplines and to understand the evolution of the research area.More specifically,for the inaccuracy of the consecutive conferences sequences extracted from publication sequences,a new method is presented to extract sequences based on time slice information,so that the clustering accuracy can be improved.The quantitative and qualitative analysis of experiments in real datasets has been provided to illustrate the effectiveness of proposed method.
Researchers' publication sequence contain some important information which can be utilized to discover the research areas trend,reflect the relative ranking of academic conferences,and indicate the hot research topics.A systematic method is proposed to discover the knowledge hidden in the publication sequences to identify the connection between different research disciplines and to understand the evolution of the research area.More specifically,for the inaccuracy of the consecutive conferences sequences extracted from publication sequences,a new method is presented to extract sequences based on time slice information,so that the clustering accuracy can be improved.The quantitative and qualitative analysis of experiments in real datasets has been provided to illustrate the effectiveness of proposed method.
2010, 39(1): 114-118.
doi: 10.3969/j.issn.1001-0548.2010.01.026
Abstract:
Delegation is an important security policy supported by role based access control (RBAC) model. Based on the idea of components and role based aceess control model,this paper presents a constraint hierarchy Role-Based delegation model with time constraint,partial delegation constraint,roles dependency constraint,and roles conflicts constraint.The paper also explores some issues including conflicts examining algorithm and rights computing algorithm.In the end,an application example is provided using this model.
Delegation is an important security policy supported by role based access control (RBAC) model. Based on the idea of components and role based aceess control model,this paper presents a constraint hierarchy Role-Based delegation model with time constraint,partial delegation constraint,roles dependency constraint,and roles conflicts constraint.The paper also explores some issues including conflicts examining algorithm and rights computing algorithm.In the end,an application example is provided using this model.
2010, 39(1): 119-122.
doi: 10.3969/j.issn.1001-0548.2010.01.027
Abstract:
For dense wireless sensor networks (WSN),nodes working staggerly is one efficient approach of extending network's lifetime.An analysis of random sensor scheduling algorithm based on COVER is conducted in this paper.The definition of coverage intensity in k-coverage network is presented and its corresponding formula is estimated using elementary probability theory.A precise analysis about 2-coverage network and a mathematical relationship among coverage intensity,node density and the level of energy conserving (i.e.,the number of deploying nodes n,the coverage intensity of 2-coverage network Cn2,and the number of divided Cover c) are proposed.The result can be applied to deploy an energy-efficiency WSN possessing of high fault-tolerant performance.
For dense wireless sensor networks (WSN),nodes working staggerly is one efficient approach of extending network's lifetime.An analysis of random sensor scheduling algorithm based on COVER is conducted in this paper.The definition of coverage intensity in k-coverage network is presented and its corresponding formula is estimated using elementary probability theory.A precise analysis about 2-coverage network and a mathematical relationship among coverage intensity,node density and the level of energy conserving (i.e.,the number of deploying nodes n,the coverage intensity of 2-coverage network Cn2,and the number of divided Cover c) are proposed.The result can be applied to deploy an energy-efficiency WSN possessing of high fault-tolerant performance.
2010, 39(1): 123-127.
doi: 10.3969/j.issn.1001-0548.2010.01.028
Abstract:
An object-oriented 3D graphics engine is presented and implemented.The general architecture,the relationships of every module,and the key techniques of the engine are discussed.This engine can support extendable software architectures,and provide high efficient scene rendering method and convenient application programming interfaces.It can greatly accelerate the development of 3D graphics and provide supports for its efficient running.Experimental results show that this engine has high stability and high rendering speed,for rendering large-scale out-door scene,the speed is still above 20 fps.
An object-oriented 3D graphics engine is presented and implemented.The general architecture,the relationships of every module,and the key techniques of the engine are discussed.This engine can support extendable software architectures,and provide high efficient scene rendering method and convenient application programming interfaces.It can greatly accelerate the development of 3D graphics and provide supports for its efficient running.Experimental results show that this engine has high stability and high rendering speed,for rendering large-scale out-door scene,the speed is still above 20 fps.
2010, 39(1): 128-132.
doi: 10.3969/j.issn.1001-0548.2010.01.029
Abstract:
Digital images have many intrinsic features such as large amount of data information,highly redundancy,and strong correlation among pixels and so on.A new method of image encryption based on bivariate polynomials is proposed according to the characters of images.In the process of image encryption,another digital image is used as the key,in this way the size of the image key could be much smaller than the secret image.The majority of steps of encryption and decryption just are add operations over a finite field,so the new method has highly efficiency.In addition,the method can be expanded to the video encryption field easily.
Digital images have many intrinsic features such as large amount of data information,highly redundancy,and strong correlation among pixels and so on.A new method of image encryption based on bivariate polynomials is proposed according to the characters of images.In the process of image encryption,another digital image is used as the key,in this way the size of the image key could be much smaller than the secret image.The majority of steps of encryption and decryption just are add operations over a finite field,so the new method has highly efficiency.In addition,the method can be expanded to the video encryption field easily.
2010, 39(1): 133-136.
doi: 10.3969/j.issn.1001-0548.2010.01.030
Abstract:
A class of new binary maximum distance separable (MDS) array codes called V-Code is presented. The V-Codes have a simple geometrical structure,namely,they can correct any double column erasure errors.In addition,the parity symbols are evenly distributed among all the columns,thus the bottleneck effects of repeated write operation are naturally overcome.A detailed V code's decoding algorithms for correcting various double node failures with a geometrical structure is provided.The complexity of encoding and decoding and the small write performance of other types of codes are compared and analyzed.
A class of new binary maximum distance separable (MDS) array codes called V-Code is presented. The V-Codes have a simple geometrical structure,namely,they can correct any double column erasure errors.In addition,the parity symbols are evenly distributed among all the columns,thus the bottleneck effects of repeated write operation are naturally overcome.A detailed V code's decoding algorithms for correcting various double node failures with a geometrical structure is provided.The complexity of encoding and decoding and the small write performance of other types of codes are compared and analyzed.
2010, 39(1): 137-140,148.
doi: 10.3969/j.issn.1001-0548.2010.01.031
Abstract:
A force-directed scheduling algorithm for optimized peak power is proposed based on single cycle operation and multi-cycle operation.The balanced distribution of cycle power in the schedule process is realized through utilizing the basic idea of traditional force-directed scheduling algorithm and resetting the related force parameters,thus the goal of minimum peak power is achieved.Experimental results show that with the same number of control steps and resources,the algorithm proposed in this paper achieves performance in peak power optimization better than traditional force-directed scheduling algorithms,and equivalent to integer linear programming methods.
A force-directed scheduling algorithm for optimized peak power is proposed based on single cycle operation and multi-cycle operation.The balanced distribution of cycle power in the schedule process is realized through utilizing the basic idea of traditional force-directed scheduling algorithm and resetting the related force parameters,thus the goal of minimum peak power is achieved.Experimental results show that with the same number of control steps and resources,the algorithm proposed in this paper achieves performance in peak power optimization better than traditional force-directed scheduling algorithms,and equivalent to integer linear programming methods.
2010, 39(1): 141-144.
doi: 10.3969/j.issn.1001-0548.2010.01.032
Abstract:
By considering the uncertainty of influence factors,a new dynamic capacity prediction model of airport's runway is proposed based on the Dempster-Shafer theory of evidence.According to the max capacity, this paper analyzes runway's capacity model,designs a recognized frame,takes the probabilities of the influence factors predicted by experts as the basic probability of evidences.At last,the Dempster fusion principles is used to get the probability of the runway's prediction dynamic capacity.Experimental results prove the rationality and feasibility of the proposed mode.
By considering the uncertainty of influence factors,a new dynamic capacity prediction model of airport's runway is proposed based on the Dempster-Shafer theory of evidence.According to the max capacity, this paper analyzes runway's capacity model,designs a recognized frame,takes the probabilities of the influence factors predicted by experts as the basic probability of evidences.At last,the Dempster fusion principles is used to get the probability of the runway's prediction dynamic capacity.Experimental results prove the rationality and feasibility of the proposed mode.
2010, 39(1): 145-148.
doi: 10.3969/j.issn.1001-0548.2010.01.033
Abstract:
The non-linear optical films were fabricated by means of alternate electrostatic adsorption with positively charged diazoresin (DR) or with negatively charged azo polymer (PAZO).Regular films growth during adsorption was proved by means of UV-vis spectroscopy.Upon the UV irradiation,accompanied with the transition of the ionic bonds between the layers to covalent bonds,the resulting multilayer films possess excellent environmental stability and high thermal stability.Optical second-harmonic generation (SHG) was observed in the multilayer films.
The non-linear optical films were fabricated by means of alternate electrostatic adsorption with positively charged diazoresin (DR) or with negatively charged azo polymer (PAZO).Regular films growth during adsorption was proved by means of UV-vis spectroscopy.Upon the UV irradiation,accompanied with the transition of the ionic bonds between the layers to covalent bonds,the resulting multilayer films possess excellent environmental stability and high thermal stability.Optical second-harmonic generation (SHG) was observed in the multilayer films.
2010, 39(1): 149-151.
doi: 10.3969/j.issn.1001-0548.2010.01.034
Abstract:
Because the small size of recording dots in quantum magnetic disk,it is very difficult to measure the magnetic field numerical distribution using the ordinary method.To prove the feasibility of quantum magnetic disk,magnetic-field distribution of quantum magnetic disk is calculated by finite element method (FEM) software. On the assumption of the magnetization direction is horizontal,we obtain 2D magnetic field distribution of circle quantum dots with diameter 20 nm and distance 10 nm and that of square quantum dots with edge 20 nm and distance 20 nm.It is proved that the magnetic fields distribute periodically and the length of period is the length of dot plus the distance between the dots.This calculation could be a good reference for the reseach of quantum magnetic disk.
Because the small size of recording dots in quantum magnetic disk,it is very difficult to measure the magnetic field numerical distribution using the ordinary method.To prove the feasibility of quantum magnetic disk,magnetic-field distribution of quantum magnetic disk is calculated by finite element method (FEM) software. On the assumption of the magnetization direction is horizontal,we obtain 2D magnetic field distribution of circle quantum dots with diameter 20 nm and distance 10 nm and that of square quantum dots with edge 20 nm and distance 20 nm.It is proved that the magnetic fields distribute periodically and the length of period is the length of dot plus the distance between the dots.This calculation could be a good reference for the reseach of quantum magnetic disk.
2010, 39(1): 152-156.
doi: 10.3969/j.issn.1001-0548.2010.01.035
Abstract:
In order to replace the conventional method of vagina palpation which has been widely used in obstetrics,a new method for detecting fetal head position and cervical dilation automatically is proposed based on the analytic geometry of space and ultrasonic triangulation.A tracking (position) model is set up and kinds of factors which may cause detecting errors are discussed.A ultrasonic measurement system for body tracking (position) is developed.The error of average result from 5 times detection by this system is less than 0.25 cm,much less than the error of a conventional vagina palpation,that is average around 2.0 cm.
In order to replace the conventional method of vagina palpation which has been widely used in obstetrics,a new method for detecting fetal head position and cervical dilation automatically is proposed based on the analytic geometry of space and ultrasonic triangulation.A tracking (position) model is set up and kinds of factors which may cause detecting errors are discussed.A ultrasonic measurement system for body tracking (position) is developed.The error of average result from 5 times detection by this system is less than 0.25 cm,much less than the error of a conventional vagina palpation,that is average around 2.0 cm.
2010, 39(1): 157-160.
doi: 10.3969/j.issn.1001-0548.2010.01.036
Abstract:
A wavelet packet method is utilized to decompose vibration signal collected from gearbox online monitoring systems.Signal reconstruction is implemented based on optimal selection of selected frequency domain. A health monitoring index is proposed,which can reflect health condition of gearbox during whole life cycle.In order to realize health warning,a dynamic threshold is proposed to detect the existence of early gear failure.Three sets of whole lifetime vibration data collected from gearboxes are used to validate this method.The analysis results illustrate that the proposed method has good performance in detecting early gear failure and owns great potential in engineering applications.
A wavelet packet method is utilized to decompose vibration signal collected from gearbox online monitoring systems.Signal reconstruction is implemented based on optimal selection of selected frequency domain. A health monitoring index is proposed,which can reflect health condition of gearbox during whole life cycle.In order to realize health warning,a dynamic threshold is proposed to detect the existence of early gear failure.Three sets of whole lifetime vibration data collected from gearboxes are used to validate this method.The analysis results illustrate that the proposed method has good performance in detecting early gear failure and owns great potential in engineering applications.
