ISSN 
2009 Vol. 38, No. 2
2009, 38(2): 161-164.
doi: 10.3969/j.issn.1001-0548.2009.02.01
Abstract:
A dynamic multi-dimensional scaling (MDS) algorithm is presented by modifying the classical MDS which uses instantaneous measurement for each location. The proposed algorithm is simple, computationally efficient, therefore allows real-time processing. It performs better when the number of measurement is more than four. Classical MDS is equal to the proposed algorithm when the number of measurement is only one.
A dynamic multi-dimensional scaling (MDS) algorithm is presented by modifying the classical MDS which uses instantaneous measurement for each location. The proposed algorithm is simple, computationally efficient, therefore allows real-time processing. It performs better when the number of measurement is more than four. Classical MDS is equal to the proposed algorithm when the number of measurement is only one.
2009, 38(2): 165-168.
doi: 10.3969/j.issn.1001-0548.2009.02.02
Abstract:
The analysis of the influence of random frequency fluctuation on bistatic SAR resolution is presented, shows that Gaussian function can be used as optimum weighting function to get the best achievable root mean square resolution. The closed-form result of the best achievable root mean square resolution is given. The results of simulation show that the closed-form expression can evaluate bistatic SAR resolution accurately, provide a basis for practical system design.
The analysis of the influence of random frequency fluctuation on bistatic SAR resolution is presented, shows that Gaussian function can be used as optimum weighting function to get the best achievable root mean square resolution. The closed-form result of the best achievable root mean square resolution is given. The results of simulation show that the closed-form expression can evaluate bistatic SAR resolution accurately, provide a basis for practical system design.
2009, 38(2): 169-172.
doi: 10.3969/j.issn.1001-0548.2009.02.03
Abstract:
The basic geometrical relationship of non-cooperative bistatic radar is introduced,and the measuring methods of four parameters (baseline distance, bistatic distance difference, transmitter look angle, receiver look angle), which can compose four distance measuring methods, are discussed. In the condition of considering the error of baseline distance, the error expressions of four distance measuring methods are deduced. The simulation results show that the distance measuring accuracy of each method is relative to the geometrical position of bistatic radar,and the district of highest distance measuring accuracy in space can be achieved by optimization. In practical systems, the selection of distance measuring method should depend on the parameters which can be measured,and the applicable region of each method should be taken in consideration.
The basic geometrical relationship of non-cooperative bistatic radar is introduced,and the measuring methods of four parameters (baseline distance, bistatic distance difference, transmitter look angle, receiver look angle), which can compose four distance measuring methods, are discussed. In the condition of considering the error of baseline distance, the error expressions of four distance measuring methods are deduced. The simulation results show that the distance measuring accuracy of each method is relative to the geometrical position of bistatic radar,and the district of highest distance measuring accuracy in space can be achieved by optimization. In practical systems, the selection of distance measuring method should depend on the parameters which can be measured,and the applicable region of each method should be taken in consideration.
2009, 38(2): 173-176.
doi: 10.3969/j.issn.1001-0548.2009.02.04
Abstract:
When radar operates on pulse state, it will inevitably encounter the phenomenon of blind speed. The staggered pulse repetition frequency(PRF) is one of the most important methods to suppressing the blind speed. Based on the derivation of frequency response, this paper proposes a method of optimum design for staggered periods, among which the considerations, derivation for several essential parameters of optimal search are also given out in detail. The simulation results, the frequency response figures show that the proposed method can achieve satisfactory suppression performance of blind speed.
When radar operates on pulse state, it will inevitably encounter the phenomenon of blind speed. The staggered pulse repetition frequency(PRF) is one of the most important methods to suppressing the blind speed. Based on the derivation of frequency response, this paper proposes a method of optimum design for staggered periods, among which the considerations, derivation for several essential parameters of optimal search are also given out in detail. The simulation results, the frequency response figures show that the proposed method can achieve satisfactory suppression performance of blind speed.
2009, 38(2): 177-181.
doi: 10.3969/j.issn.1001-0548.2009.02.05
Abstract:
A blind estimation method for pseudo noise (PN) sequence estimation of aperiodic direct sequence spread spectrum (DS) signals under condition of lower signal noise ratio (SNR) is presented. The proposed method estimates the PN sequence with segmented matrix eigenvalue decomposition (SEVD) method whose segment length equals double information bits,and then shells off the random information bits from the estimated sequences to obtain the original PN sequence based on the optimal shift-and-add property. The method accelerates the computation speed by applying parallel computing without need of prior synchronization information,and it can sweep off the “code blurring” phenomena. Simulation results show that the aperiodic DS signal with m sequence period 1 023 can be estimated without any errors as long as the SNR is above ?17 dB.
A blind estimation method for pseudo noise (PN) sequence estimation of aperiodic direct sequence spread spectrum (DS) signals under condition of lower signal noise ratio (SNR) is presented. The proposed method estimates the PN sequence with segmented matrix eigenvalue decomposition (SEVD) method whose segment length equals double information bits,and then shells off the random information bits from the estimated sequences to obtain the original PN sequence based on the optimal shift-and-add property. The method accelerates the computation speed by applying parallel computing without need of prior synchronization information,and it can sweep off the “code blurring” phenomena. Simulation results show that the aperiodic DS signal with m sequence period 1 023 can be estimated without any errors as long as the SNR is above ?17 dB.
2009, 38(2): 182-185.
doi: 10.3969/j.issn.1001-0548.2009.02.06
Abstract:
The product high-order ambiguity function (PHAF), originally proposed for analyzing multicomponent polynomial phase signal (mc-PPS), is still troubled by interference terms in the estimation of mc-PPS. In this paper, a scheme to mitigate interference terms is proposed by iteratively filtering all the components corresponding to the strongest peak of the PHAF. The improved version of PHAF has better precision, smaller blind area, threshold of signal to noise ratio, can estimate lower order phase coefficients. The performance of the new method is verified by simulations with mc-PPS's.
The product high-order ambiguity function (PHAF), originally proposed for analyzing multicomponent polynomial phase signal (mc-PPS), is still troubled by interference terms in the estimation of mc-PPS. In this paper, a scheme to mitigate interference terms is proposed by iteratively filtering all the components corresponding to the strongest peak of the PHAF. The improved version of PHAF has better precision, smaller blind area, threshold of signal to noise ratio, can estimate lower order phase coefficients. The performance of the new method is verified by simulations with mc-PPS's.
2009, 38(2): 186-189.
doi: 10.3969/j.issn.1001-0548.2009.02.07
Abstract:
To enhance fairness between users with different data rate requirements in resource allocation process, this paper extends the proportional fair (PF) algorithm, proposes a packet scheduling algorithm for the third generation partnership project (3GPP) long term evolution (LTE) uplink systems. The algorithm allocates resources to users according to their data rate requirements. The weight factor in the algorithm updates in every scheduling process, so that users with high data rate requirement but in bad instantaneous channel state will not be allocated excessive resource. Simulation results show that the proposed algorithm has a better performance in fairness between different users than PF algorithm.
To enhance fairness between users with different data rate requirements in resource allocation process, this paper extends the proportional fair (PF) algorithm, proposes a packet scheduling algorithm for the third generation partnership project (3GPP) long term evolution (LTE) uplink systems. The algorithm allocates resources to users according to their data rate requirements. The weight factor in the algorithm updates in every scheduling process, so that users with high data rate requirement but in bad instantaneous channel state will not be allocated excessive resource. Simulation results show that the proposed algorithm has a better performance in fairness between different users than PF algorithm.
2009, 38(2): 190-193.
doi: 10.3969/j.issn.1001-0548.2009.02.08
Abstract:
Radio frequency power amplifiers are analyzed in respect of their characteristics including the relation between the output response, the time constant of the gate dc bias circuits, error vector magnitude (EVM), adjacent channel power ratio (ACPR) of the output signal. A power amplifier with 33 dBm output power at 2 GHz is desighed, tested to verify the analysis. When the dynamic gate bias voltage works in a time constant of 1 ms, the amplifier is measured with EVM of 2.5%, ACPR of ?43 dB. After a redesign for the control signal with 1.5 μs ahead shift, EVM of 1.8%, ACPR of ?45 dB are achieved, which are compatible with the standards of TD-SCDMA.
Radio frequency power amplifiers are analyzed in respect of their characteristics including the relation between the output response, the time constant of the gate dc bias circuits, error vector magnitude (EVM), adjacent channel power ratio (ACPR) of the output signal. A power amplifier with 33 dBm output power at 2 GHz is desighed, tested to verify the analysis. When the dynamic gate bias voltage works in a time constant of 1 ms, the amplifier is measured with EVM of 2.5%, ACPR of ?43 dB. After a redesign for the control signal with 1.5 μs ahead shift, EVM of 1.8%, ACPR of ?45 dB are achieved, which are compatible with the standards of TD-SCDMA.
2009, 38(2): 194-197.
doi: 10.3969/j.issn.1001-0548.2009.02.09
Abstract:
With the progress of the differential technology, typical error source of global navigation satellite system (GNSS) receivers have been greatly reduced, while the multi-path ranging error remains the dominant one. To address this problem, the multi-path effects on code measurements, carrier-phase measurements are first analyzed in this paper. A low complexity code multi-path mitigation algorithm for the C/A code receivers based on the carrier-aided smoothing is then introduced, detailed. The code multi-path error is reduced from tens of meters to sub-meter, the C/A code GNSS receiver positioning accuracy is thus greatly improved. System simulation validates the proposed method.
With the progress of the differential technology, typical error source of global navigation satellite system (GNSS) receivers have been greatly reduced, while the multi-path ranging error remains the dominant one. To address this problem, the multi-path effects on code measurements, carrier-phase measurements are first analyzed in this paper. A low complexity code multi-path mitigation algorithm for the C/A code receivers based on the carrier-aided smoothing is then introduced, detailed. The code multi-path error is reduced from tens of meters to sub-meter, the C/A code GNSS receiver positioning accuracy is thus greatly improved. System simulation validates the proposed method.
2009, 38(2): 198-201.
doi: 10.3969/j.issn.1001-0548.2009.02.10
Abstract:
Inherent inter-symbol, inter-carrier interference elimination ability of orthogonal frequency division multiplexing (OFDM) system attribute to its cyclic prefix. But the case of multipath fading channels whose the channel impulse response (CIR) length exceeds the duration of cyclic prefix (CP) causes intersymbol interference (ISI), intercarrier interference (ICI), which may degrade system performance severely. Conventional channel estimation, equalization schemes, if applied to this case of insufficient CP, suffer significant performance degradation. This paper presents a channel estimation scheme that enables the estimation of a complete CIR even beyond the CP length. A Zero-forcing (ZF) based low complexity equalizer for the suppression of insufficient CP generated interference is also derived. Simulation results for the proposed schemes show the advantage of significantly lower computational complexity, compared with earlier schemes, without any loss in performance, transmission efficiency.
Inherent inter-symbol, inter-carrier interference elimination ability of orthogonal frequency division multiplexing (OFDM) system attribute to its cyclic prefix. But the case of multipath fading channels whose the channel impulse response (CIR) length exceeds the duration of cyclic prefix (CP) causes intersymbol interference (ISI), intercarrier interference (ICI), which may degrade system performance severely. Conventional channel estimation, equalization schemes, if applied to this case of insufficient CP, suffer significant performance degradation. This paper presents a channel estimation scheme that enables the estimation of a complete CIR even beyond the CP length. A Zero-forcing (ZF) based low complexity equalizer for the suppression of insufficient CP generated interference is also derived. Simulation results for the proposed schemes show the advantage of significantly lower computational complexity, compared with earlier schemes, without any loss in performance, transmission efficiency.
2009, 38(2): 202-205.
doi: 10.3969/j.issn.1001-0548.2009.02.11
Abstract:
An efficient inter predictive pixel compensator for audio video coding standard (AVS) is presented. It generates one predictive pixel result per cycle, uses dual-port memory to reduce data latency. 3-stage pipeline architecture is used to calculate compensation pixel for increasing frequency, 3-stage reusable filters are used to calculate the 1/4 predictive pixel for saving circuit cost. Simulation shows that the module implemented can achieve AVS HD real-time decoding.
An efficient inter predictive pixel compensator for audio video coding standard (AVS) is presented. It generates one predictive pixel result per cycle, uses dual-port memory to reduce data latency. 3-stage pipeline architecture is used to calculate compensation pixel for increasing frequency, 3-stage reusable filters are used to calculate the 1/4 predictive pixel for saving circuit cost. Simulation shows that the module implemented can achieve AVS HD real-time decoding.
2009, 38(2): 206-209.
doi: 10.3969/j.issn.1001-0548.2009.02.12
Abstract:
A Q-Band frequency quadrupler-amplifier module is designed to operate from 33 GHz to 50 GHz. This module consists of two stages frequency doublers, a bandpass filter between two frequency doublers, a millimeter wave power amplifier with a microstrip of waveguide transition. The wide bandwidth bandpass filter is designed to suppress the fundamental, third harmonic signals. In the range of 33 GHz to 50 GHz output frequencies, the measured output power is more than 10.5 dB, the third harmonic signal rejection is better than 31.6dBc.
A Q-Band frequency quadrupler-amplifier module is designed to operate from 33 GHz to 50 GHz. This module consists of two stages frequency doublers, a bandpass filter between two frequency doublers, a millimeter wave power amplifier with a microstrip of waveguide transition. The wide bandwidth bandpass filter is designed to suppress the fundamental, third harmonic signals. In the range of 33 GHz to 50 GHz output frequencies, the measured output power is more than 10.5 dB, the third harmonic signal rejection is better than 31.6dBc.
2009, 38(2): 210-213.
doi: 10.3969/j.issn.1001-0548.2009.02.13
Abstract:
The multi-beam reflector antenna is the front-end receiver of the passive imaging system. Due to spatial coherence effect of electromagnetic field, the uniform multi-beam parabolic reflector antenna is analyzed. The calculated results show that the beam generated by a multi-feeds parabolic reflector antenna is a coherent beam not a multi-beam when the distance of feeds reduced. It is proved that the effect of spatial coherence will reduce, the independent beam will arise when the distance of feeds is increased. The analysis is validated by FEKO soft.
The multi-beam reflector antenna is the front-end receiver of the passive imaging system. Due to spatial coherence effect of electromagnetic field, the uniform multi-beam parabolic reflector antenna is analyzed. The calculated results show that the beam generated by a multi-feeds parabolic reflector antenna is a coherent beam not a multi-beam when the distance of feeds reduced. It is proved that the effect of spatial coherence will reduce, the independent beam will arise when the distance of feeds is increased. The analysis is validated by FEKO soft.
2009, 38(2): 214-217.
doi: 10.3969/j.issn.1001-0548.2009.02.14
Abstract:
A new device using image sapphire resonator method is introduced for measuring the microwave resistance of high temperature superconductor (HTS) thin films. Coupling hole was used in this device for the stimulation of resonator. A 6 mm×3 mm×8 mm dielectric waveguide, an L type coupling loop made of roasting silver situating in the section plane of the dielectric waveguide are used for the EM transmitting. This coupling structure is a new attempt for low temperature measurement. The microwave surface resistances (RS) of two YBCO films about 2 inches deposited on MgO substrates are measured.
A new device using image sapphire resonator method is introduced for measuring the microwave resistance of high temperature superconductor (HTS) thin films. Coupling hole was used in this device for the stimulation of resonator. A 6 mm×3 mm×8 mm dielectric waveguide, an L type coupling loop made of roasting silver situating in the section plane of the dielectric waveguide are used for the EM transmitting. This coupling structure is a new attempt for low temperature measurement. The microwave surface resistances (RS) of two YBCO films about 2 inches deposited on MgO substrates are measured.
2009, 38(2): 222-226.
doi: 10.3969/j.issn.1001-0548.2009.02.16
Abstract:
A high performance hybrid parallel PDTD algorithm in developed by introducing the concept of two layers of parallel capacity based on local area network(LAN). In the hybrid algorithm, MPI is used in conjunction with OpenMP multithreading to achieve two level parallelism of the data, tasks at the basis of the domain decomposition FDTD method. By using this hybrid algorithm, a common hidden printed antenna for automobile is simulated. Computation results show when the grain size of the domain decomposition is on the small side, this novel hybrid parallelization scheme is an effective technique for improving the efficiency of the parallel FDTD based on LAN.
A high performance hybrid parallel PDTD algorithm in developed by introducing the concept of two layers of parallel capacity based on local area network(LAN). In the hybrid algorithm, MPI is used in conjunction with OpenMP multithreading to achieve two level parallelism of the data, tasks at the basis of the domain decomposition FDTD method. By using this hybrid algorithm, a common hidden printed antenna for automobile is simulated. Computation results show when the grain size of the domain decomposition is on the small side, this novel hybrid parallelization scheme is an effective technique for improving the efficiency of the parallel FDTD based on LAN.
2009, 38(2): 227-230.
doi: 10.3969/j.issn.1001-0548.2009.02.17
Abstract:
A genetic algorithm (GA) to solve the problem of path optimization of wireless sensor network (WSN) is proposed. Considering the influences of some practical factors such as the consumption of the energy of the nodes, recovery time of routing, we treat these influences as constraint conditions of path optimization. In order to prolong the lifetime of WSN, variety constraint conditions, multiple objectives are considered according to the priority of importance. The performances of GA are analyzed carefully in this paper, including chromosome representation, coding, fitness function design, genetic operator design, parameters analysis, selection. A large quantity of simulation experiments show that GA is a quick, effective way to find valid optimized route of WSN.
A genetic algorithm (GA) to solve the problem of path optimization of wireless sensor network (WSN) is proposed. Considering the influences of some practical factors such as the consumption of the energy of the nodes, recovery time of routing, we treat these influences as constraint conditions of path optimization. In order to prolong the lifetime of WSN, variety constraint conditions, multiple objectives are considered according to the priority of importance. The performances of GA are analyzed carefully in this paper, including chromosome representation, coding, fitness function design, genetic operator design, parameters analysis, selection. A large quantity of simulation experiments show that GA is a quick, effective way to find valid optimized route of WSN.
2009, 38(2): 231-235.
doi: 10.3969/j.issn.1001-0548.2009.02.18
Abstract:
The connected dominating tree with bounded transmission delay problem (CDTT) is defined based on (α,β)-tree for the construction of connected dominating set (CDS) in wireless sensor network., distributed connected dominating tree (CDT) algorithm is proposed to construct a CDT-tree with limited total power while moderating the constraint of the transmission delays. Our distributed algorithm for CDS consists of two phases: firstly construct a maximal independent set (MIS) based on a unit disk graph,and then implement the CDT algorithm based on a double weighted, undirected graph satisfying the requirements of energy consumption, transmission delays simultaneously with O(n2) time, message complexity. The theoretical analysis, simulation results show that the CDT algorithm gives an effective solution to the CDTT problem, construct the CDS with combined constraints.
The connected dominating tree with bounded transmission delay problem (CDTT) is defined based on (α,β)-tree for the construction of connected dominating set (CDS) in wireless sensor network., distributed connected dominating tree (CDT) algorithm is proposed to construct a CDT-tree with limited total power while moderating the constraint of the transmission delays. Our distributed algorithm for CDS consists of two phases: firstly construct a maximal independent set (MIS) based on a unit disk graph,and then implement the CDT algorithm based on a double weighted, undirected graph satisfying the requirements of energy consumption, transmission delays simultaneously with O(n2) time, message complexity. The theoretical analysis, simulation results show that the CDT algorithm gives an effective solution to the CDTT problem, construct the CDS with combined constraints.
2009, 38(2): 236-239.
doi: 10.3969/j.issn.1001-0548.2009.02.19
Abstract:
A three-dimensional, time-dependent,and self-consistent fluid model is developed to simulate the helium plasma in a cylindrical microhollow cathode (MHCD) with reasonable boundary conditions. The particle density, electric potential, electron energy,and the distribution of the electric field are calculated. The results show that there exist the cathode dark space region, negative glow region,and the hollow cathode effect is in evidence. The results presented in this paper provide an understanding of the basic mechanisms governing the MHCD devices.
A three-dimensional, time-dependent,and self-consistent fluid model is developed to simulate the helium plasma in a cylindrical microhollow cathode (MHCD) with reasonable boundary conditions. The particle density, electric potential, electron energy,and the distribution of the electric field are calculated. The results show that there exist the cathode dark space region, negative glow region,and the hollow cathode effect is in evidence. The results presented in this paper provide an understanding of the basic mechanisms governing the MHCD devices.
2009, 38(2): 240-244.
doi: 10.3969/j.issn.1001-0548.2009.02.20
Abstract:
A new network intrusion detection classification model is presented, a support vector machine (SVM) based classifier is given. A factor analysis (FA) algorithm is utilized to fuse numerous related network behavior features into concise integrated features so as to reduce network data dimensions. A support vector decision function ranking method (SVDFRM) is used to calculate the contribution of network behaviors features,and then important network behaviors features are extracted. The experimental results demonstrate that this model has good dimension reduction performance, real time performance,and satisfied detection rate.
A new network intrusion detection classification model is presented, a support vector machine (SVM) based classifier is given. A factor analysis (FA) algorithm is utilized to fuse numerous related network behavior features into concise integrated features so as to reduce network data dimensions. A support vector decision function ranking method (SVDFRM) is used to calculate the contribution of network behaviors features,and then important network behaviors features are extracted. The experimental results demonstrate that this model has good dimension reduction performance, real time performance,and satisfied detection rate.
2009, 38(2): 245-248.
doi: 10.3969/j.issn.1001-0548.2009.02.21
Abstract:
Handoff latency arisen in access points (APs) has become essential issue in wireless local area network (WLAN). The delay caused by handoff process affects the quality of service (QoS), such as real-time applications like VoIP. In order to resolve this problem, an improved fast handoff algorithm is proposed to confirm, authorize and connect the next AP. According to the moving speed and excursion angle, a threshold value of distance and received signal strength (RSS) is determined between mobile nodes (MNs) and the connecting AP. This algorithm has been used in a signal system of subway. The test results show that the delay caused by handoff process is reduced and the probability of success handoff is increased.
Handoff latency arisen in access points (APs) has become essential issue in wireless local area network (WLAN). The delay caused by handoff process affects the quality of service (QoS), such as real-time applications like VoIP. In order to resolve this problem, an improved fast handoff algorithm is proposed to confirm, authorize and connect the next AP. According to the moving speed and excursion angle, a threshold value of distance and received signal strength (RSS) is determined between mobile nodes (MNs) and the connecting AP. This algorithm has been used in a signal system of subway. The test results show that the delay caused by handoff process is reduced and the probability of success handoff is increased.
2009, 38(2): 249-252.
doi: 10.3969/j.issn.1001-0548.2009.02.22
Abstract:
Prediction by partial match (PPM) models are commonly used for web prefetching. But most of existing models are not adaptive and can not represent the change of user browsing behaviors. By extending the standard PPM model, we present an adaptive Web prediction model based on sliding window. The model only keeps the most recent requests by a sliding window to indicate user interest changing. In order to improve the updating speed, it makes use of non-compact suffix tree to incrementally insert the new user request and delete the outdated browsing information. Trace-driven experiments show that our model can significantly improve the prefetching performance.
Prediction by partial match (PPM) models are commonly used for web prefetching. But most of existing models are not adaptive and can not represent the change of user browsing behaviors. By extending the standard PPM model, we present an adaptive Web prediction model based on sliding window. The model only keeps the most recent requests by a sliding window to indicate user interest changing. In order to improve the updating speed, it makes use of non-compact suffix tree to incrementally insert the new user request and delete the outdated browsing information. Trace-driven experiments show that our model can significantly improve the prefetching performance.
2009, 38(2): 253-257.
doi: 10.3969/j.issn.1001-0548.2009.02.23
Abstract:
Fault induction attack assumes that the attacker is able to induct faults into the cryptographic device (smartcard) and make it output incorrect encryption results. The attacker exploits the correct and incorrect encryption results to disclose the secret information (key) hidden in the cryptographic device. A method of the fault induction attack on RC4 algorithm is brought forward. The simulations show that one attack may find the values of 3 positions in the initial state of RC4 and continuous attacks can recover the whole initial state of RC4 with a considerable probability (more than 1/2). About O(2 16) key stream bytes at most are needed to recover the whole initial state of RC4 after about O(2 16) fault inductions at most.
Fault induction attack assumes that the attacker is able to induct faults into the cryptographic device (smartcard) and make it output incorrect encryption results. The attacker exploits the correct and incorrect encryption results to disclose the secret information (key) hidden in the cryptographic device. A method of the fault induction attack on RC4 algorithm is brought forward. The simulations show that one attack may find the values of 3 positions in the initial state of RC4 and continuous attacks can recover the whole initial state of RC4 with a considerable probability (more than 1/2). About O(2 16) key stream bytes at most are needed to recover the whole initial state of RC4 after about O(2 16) fault inductions at most.
2009, 38(2): 258-261.
doi: 10.3969/j.issn.1001-0548.2009.02.24
Abstract:
Intrusion detection message exchange format (IDMEF) standard has been widely used in intrusion detection system (IDS). This paper proposes an architecture of large scale cooperative IDS based on IDMEF. The design and implementation of the cooperative IDS are discussed by the means of Prelude framework and development suite. The deployment and application of this architecture on CERNET are finally analyzed.
Intrusion detection message exchange format (IDMEF) standard has been widely used in intrusion detection system (IDS). This paper proposes an architecture of large scale cooperative IDS based on IDMEF. The design and implementation of the cooperative IDS are discussed by the means of Prelude framework and development suite. The deployment and application of this architecture on CERNET are finally analyzed.
2009, 38(2): 262-265.
doi: 10.3969/j.issn.1001-0548.2009.02.25
Abstract:
To counter the attack and propagation of passive worms in large-scale peer-to-peer(P2P) file-sharing networks, three propagating models of passive worms suitable for different stages of worm propagation, are proposed based on deep analysis on the features of file sharing and passive worm propagation. In order to verify the validity of the three modes, large scale simulating experiments are carried out. To simulate the true popular P2P file-sharing networks, a simulating software is developed based on the P2P simulating platform PeerSim. Theory analysis and simulation show that these models are valid and can predict the tendency and behaviors of worm propagation.
To counter the attack and propagation of passive worms in large-scale peer-to-peer(P2P) file-sharing networks, three propagating models of passive worms suitable for different stages of worm propagation, are proposed based on deep analysis on the features of file sharing and passive worm propagation. In order to verify the validity of the three modes, large scale simulating experiments are carried out. To simulate the true popular P2P file-sharing networks, a simulating software is developed based on the P2P simulating platform PeerSim. Theory analysis and simulation show that these models are valid and can predict the tendency and behaviors of worm propagation.
2009, 38(2): 266-269.
doi: 10.3969/j.issn.1001-0548.2009.02.26
Abstract:
To solve the problem of low convergence speed and congestion and oscillation in conventional routing algorithms, a novel method of dynamic routing algorithm for multimedia network is proposed based on ant colony optimization (ACO) algorithm and genetic algorithms (GAs). The essential advantages of ACO including cooperation, positive feedback, and distributed nature and the disadvantages of low convergence speed are discussed. By considering the high adaptability of GAs, the cross operation and mutation of genetic algorithms are introduced into the ACO to improve its searching ability and to dynamically adjust the influence of each ant for the trail information updating and the selected probabilities of the paths. The algorithm is also well suited for dynamic networks and can make the selected paths shortest, miss the traffic jams and keep the balance of networks load distribution.
To solve the problem of low convergence speed and congestion and oscillation in conventional routing algorithms, a novel method of dynamic routing algorithm for multimedia network is proposed based on ant colony optimization (ACO) algorithm and genetic algorithms (GAs). The essential advantages of ACO including cooperation, positive feedback, and distributed nature and the disadvantages of low convergence speed are discussed. By considering the high adaptability of GAs, the cross operation and mutation of genetic algorithms are introduced into the ACO to improve its searching ability and to dynamically adjust the influence of each ant for the trail information updating and the selected probabilities of the paths. The algorithm is also well suited for dynamic networks and can make the selected paths shortest, miss the traffic jams and keep the balance of networks load distribution.
2009, 38(2): 270-273.
doi: 10.3969/j.issn.1001-0548.2009.02.27
Abstract:
In some languages, all the sentences must include or exclude some specific substrings. Sometimes, the substrings must be replaced. It is difficult for a Turing machine to accept such languages. Traditional method is based on the storage technique. In this paper, we present a new method, the scanning substring techonology. In the method, the specific substring is treated as a single unit. Multiple status transition functions of the Turing machine are combined to scan multiple characters at one time, but the read/write head only moves one unit. Through some examples, the paper shows that the Turing machine which scans multiple characters is equivalent to a Turing machine scanning one character.
In some languages, all the sentences must include or exclude some specific substrings. Sometimes, the substrings must be replaced. It is difficult for a Turing machine to accept such languages. Traditional method is based on the storage technique. In this paper, we present a new method, the scanning substring techonology. In the method, the specific substring is treated as a single unit. Multiple status transition functions of the Turing machine are combined to scan multiple characters at one time, but the read/write head only moves one unit. Through some examples, the paper shows that the Turing machine which scans multiple characters is equivalent to a Turing machine scanning one character.
2009, 38(2): 275-277.
doi: 10.3969/j.issn.1001-0548.2009.02.28
Abstract:
A new cryptosystem based on multiple one-dimensional chaotic maps is proposed by utilizing the properties of chaotic map such as sensitivity to initial conditions and system parameters, and orbit uncertainty. The system parameters of chaotic maps and the using order of three one-dimensional maps are generated by using linear congruent generators. The initial value and iterative number of chaotic map and linear congruence generator (LCG) parameters are dynamically changed by output feedback. Simulation results and security analyses show that the proposed cryptosystem has large key space and high sensitivity to key and plaintext, and can resist the brute attack and statistical attack.
A new cryptosystem based on multiple one-dimensional chaotic maps is proposed by utilizing the properties of chaotic map such as sensitivity to initial conditions and system parameters, and orbit uncertainty. The system parameters of chaotic maps and the using order of three one-dimensional maps are generated by using linear congruent generators. The initial value and iterative number of chaotic map and linear congruence generator (LCG) parameters are dynamically changed by output feedback. Simulation results and security analyses show that the proposed cryptosystem has large key space and high sensitivity to key and plaintext, and can resist the brute attack and statistical attack.
2009, 38(2): 278-281.
doi: 10.3969/j.issn.1001-0548.2009.02.29
Abstract:
By considering the characters of liver CT image sequences, a new segmentation way is proposed based on an advanced Snake model associated with seeded region growing method. With this method, a CT image clear edges is selected from CT liver image sequences, then several seeds are selected in the liver region, the seeded region growing method is used to get an initial edge. The edge is optimized by advanced Snake model and served as the initial edge of the next CT image. This procedure is repeated until all images are processed. Experimental results show that the algorithm can obtain segmentation result of soft tissue image efficiently and accurately.
By considering the characters of liver CT image sequences, a new segmentation way is proposed based on an advanced Snake model associated with seeded region growing method. With this method, a CT image clear edges is selected from CT liver image sequences, then several seeds are selected in the liver region, the seeded region growing method is used to get an initial edge. The edge is optimized by advanced Snake model and served as the initial edge of the next CT image. This procedure is repeated until all images are processed. Experimental results show that the algorithm can obtain segmentation result of soft tissue image efficiently and accurately.
2009, 38(2): 282-287.
doi: 10.3969/j.issn.1001-0548.2009.02.30
Abstract:
In order to construct collaborative manufacturing service chain, a method for modeling and compositing manufacturing services is presented based on service oriented architecture. The granularity of manufacturing service models is discussed. According to product structure, the granularity is classified into four types: product, component, part, and working procedure. Definitions for basic manufacturing service model, extended manufacturing service model, and extended manufacturing service chain are given based on the granularity manufacturing service models. The principles and process of manufacturing service composition are proposed. Finally, a collaborative manufacturing service platform based on service oriented architecture is discussed with an example illustration.
In order to construct collaborative manufacturing service chain, a method for modeling and compositing manufacturing services is presented based on service oriented architecture. The granularity of manufacturing service models is discussed. According to product structure, the granularity is classified into four types: product, component, part, and working procedure. Definitions for basic manufacturing service model, extended manufacturing service model, and extended manufacturing service chain are given based on the granularity manufacturing service models. The principles and process of manufacturing service composition are proposed. Finally, a collaborative manufacturing service platform based on service oriented architecture is discussed with an example illustration.
2009, 38(2): 288-291.
doi: 10.3969/j.issn.1001-0548.2009.02.31
Abstract:
A kind of three level access control policy towards component is presented by extensible access control markup language (XACML) for the protection of component interaction, interface invocation, and parameters access. Based on this policy, the mutation test strategies are designed: policy mutations follow policy mutations, policyset mutations follow policy mutations, and vice versa. Both the case study and semantical verification shows that the access control of component interface and interactions can be tested by XACML mutation policies.
A kind of three level access control policy towards component is presented by extensible access control markup language (XACML) for the protection of component interaction, interface invocation, and parameters access. Based on this policy, the mutation test strategies are designed: policy mutations follow policy mutations, policyset mutations follow policy mutations, and vice versa. Both the case study and semantical verification shows that the access control of component interface and interactions can be tested by XACML mutation policies.
2009, 38(2): 292-295.
doi: 10.3969/j.issn.1001-0548.2009.02.32
Abstract:
A new improved permutation algorithm for radix 2 fast Fourier transforms (FFTs) is discribed. The algorithm provides an improved way for obtaining the bit reversal index table and affords an alternative data permutation methods. First, The algorithm divides an index with two parts, one is called group-index, which represents the index belonging to some group, and the other is called group-member which represents the order in the group. And then two arrays are used to store the values of the group-index and group-member power. According to the relationship between the bit reversal values of group-index and group-member, any bit reversal table can be obtained with the known one, which is (0,2,1,3). Second, when the data are needed to permute, the improved algorithm avoids the comparison operations between the index and its corresponding bit reversal value, which are required in the general permutation algorithm. In order to test its performance in the windows operation systems, several algorithms are programmed with C++ language, and their operation times are compared. The experiments show that the performance of the improved algorithm introduced in this paper is superior to that of the relative algorithms.
A new improved permutation algorithm for radix 2 fast Fourier transforms (FFTs) is discribed. The algorithm provides an improved way for obtaining the bit reversal index table and affords an alternative data permutation methods. First, The algorithm divides an index with two parts, one is called group-index, which represents the index belonging to some group, and the other is called group-member which represents the order in the group. And then two arrays are used to store the values of the group-index and group-member power. According to the relationship between the bit reversal values of group-index and group-member, any bit reversal table can be obtained with the known one, which is (0,2,1,3). Second, when the data are needed to permute, the improved algorithm avoids the comparison operations between the index and its corresponding bit reversal value, which are required in the general permutation algorithm. In order to test its performance in the windows operation systems, several algorithms are programmed with C++ language, and their operation times are compared. The experiments show that the performance of the improved algorithm introduced in this paper is superior to that of the relative algorithms.
2009, 38(2): 296-300.
doi: 10.3969/j.issn.1001-0548.2009.02.33
Abstract:
Based on the research of mobile digital rights management (DRM), a charging fair solution of secure mobile DRM for applications in 3G wireless communication networks is proposed. The secure mobile DRM solution guarantees the security and integrity of the digital contents and right objects, and prevents the right issuers cribbing the digital contents. Furthermore, a practical fair payment protocol without TTP is presented and used in this mobile DRM, it leads to cost reductions of protocol implementation and involving exchange. At last, the security analysis and efficiency comparison are presented.
Based on the research of mobile digital rights management (DRM), a charging fair solution of secure mobile DRM for applications in 3G wireless communication networks is proposed. The secure mobile DRM solution guarantees the security and integrity of the digital contents and right objects, and prevents the right issuers cribbing the digital contents. Furthermore, a practical fair payment protocol without TTP is presented and used in this mobile DRM, it leads to cost reductions of protocol implementation and involving exchange. At last, the security analysis and efficiency comparison are presented.
2009, 38(2): 301-304.
doi: 10.3969/j.issn.1001-0548.2009.02.34
Abstract:
Based on complex single piezoelectric layer's film bulk acoustic resonator (FBAR), a new kind of complex double piezoelectric layers' FBAR is proposed. This structure can greatly improves the flexibility of the selection of piezoelectric materials for FBAR. The analytical expression of input impedance is derived and simulated. The results of simulation show that: 1) the resonant frequency of basic mode increases significantly with the thickness ratio of the piezoelectric layer with higher acoustic speed to the whole thickness of double piezoelectric layers, 2) the relative bandwidth increases with the thickness ratio of the piezoelectric layer with higher electromechanical coupling coefficient to that with lower electromechanical coupling coefficient, and 3) some modes can be found in double piezoelectric layers' FBAR but not in the single layer's FBAR.
Based on complex single piezoelectric layer's film bulk acoustic resonator (FBAR), a new kind of complex double piezoelectric layers' FBAR is proposed. This structure can greatly improves the flexibility of the selection of piezoelectric materials for FBAR. The analytical expression of input impedance is derived and simulated. The results of simulation show that: 1) the resonant frequency of basic mode increases significantly with the thickness ratio of the piezoelectric layer with higher acoustic speed to the whole thickness of double piezoelectric layers, 2) the relative bandwidth increases with the thickness ratio of the piezoelectric layer with higher electromechanical coupling coefficient to that with lower electromechanical coupling coefficient, and 3) some modes can be found in double piezoelectric layers' FBAR but not in the single layer's FBAR.
2009, 38(2): 305-308.
doi: 10.3969/j.issn.1001-0548.2009.02.35
Abstract:
A high stability and low noise CMOS ring voltage-controlled oscillator (VCO) is designed and analyzed based on the CSMC 0.5μm process. Replica-biased circuit technique is adopted to suppress the noise from VDD and substrate. The analysis shows that the VCO can achieve better linear voltage-frequency characteristic and lower phase noise: when VCO control voltage varies from 1 V to 3 V, the turning range changes from 100 MHz to 500 MHz, meanwhile the phase noise are ?50 dBc/Hz, ?75 dBc/Hz, ?98 dBc/Hz, and ?120 dBc/Hz at an offset of 1 kHz, 10 kHz, 100 kHz, and 1 MHz from oscillator centre frequency, respectively.
A high stability and low noise CMOS ring voltage-controlled oscillator (VCO) is designed and analyzed based on the CSMC 0.5μm process. Replica-biased circuit technique is adopted to suppress the noise from VDD and substrate. The analysis shows that the VCO can achieve better linear voltage-frequency characteristic and lower phase noise: when VCO control voltage varies from 1 V to 3 V, the turning range changes from 100 MHz to 500 MHz, meanwhile the phase noise are ?50 dBc/Hz, ?75 dBc/Hz, ?98 dBc/Hz, and ?120 dBc/Hz at an offset of 1 kHz, 10 kHz, 100 kHz, and 1 MHz from oscillator centre frequency, respectively.
2009, 38(2): 309-312.
doi: 10.3969/j.issn.1001-0548.2009.02.36
Abstract:
A novel and efficient two-channel router using separate data and control packet channels is proposed for networks-on-chip. The new scheme is compared with the traditional signal-channel and virtual-channel routers under the same traffic conditions and constraints. The simulation results show that the proposed router performs better in terms of throughput and average delay. The gate count of the router is only 20 500, and the router area after synthesis is 0.103 mm2 under SMIC 0.13 μm CMOS process technology.
A novel and efficient two-channel router using separate data and control packet channels is proposed for networks-on-chip. The new scheme is compared with the traditional signal-channel and virtual-channel routers under the same traffic conditions and constraints. The simulation results show that the proposed router performs better in terms of throughput and average delay. The gate count of the router is only 20 500, and the router area after synthesis is 0.103 mm2 under SMIC 0.13 μm CMOS process technology.
2009, 38(2): 313-316.
doi: 10.3969/j.issn.1001-0548.2009.02.37
Abstract:
This paper presents a new approach for measuring the thermal conductance and thermal mass of silicon nitride film with suspended structure fabricated by micromachining technique. In the structure, the Pt thin film is used as both heater and temperature detector based on its temperature resistance characterization. A reasonable scheme has been designed to reduce the additional thermal conductance and thermal mass introduced by Pt thin film. During the test, when DC current is input in the Pt thin film, the microbridge temperature rises gradually until the system reaches steady. The simulation for the thermal response characterization by Matlab indicates that bigger thermal conductance and thermal mass result in higher microbridge temperature at the steady state. Finally, the impact of invalid heating Pt resistance and microfabrication process on the measurement precision is discussed and the methods to improve the precision are given.
This paper presents a new approach for measuring the thermal conductance and thermal mass of silicon nitride film with suspended structure fabricated by micromachining technique. In the structure, the Pt thin film is used as both heater and temperature detector based on its temperature resistance characterization. A reasonable scheme has been designed to reduce the additional thermal conductance and thermal mass introduced by Pt thin film. During the test, when DC current is input in the Pt thin film, the microbridge temperature rises gradually until the system reaches steady. The simulation for the thermal response characterization by Matlab indicates that bigger thermal conductance and thermal mass result in higher microbridge temperature at the steady state. Finally, the impact of invalid heating Pt resistance and microfabrication process on the measurement precision is discussed and the methods to improve the precision are given.
2009, 38(2): 317-320.
doi: 10.3969/j.issn.1001-0548.2009.02.38
Abstract:
In order to develop a bonding head mechanism with high-speed and high-precision characteristics and ensure the whole machine performance of automatic LED die bonders. A motion proposal and structure parameters of the head mechanism are designed, the motion modeling technologies and methods of the whole head mechanism are researched by using the Mechanism/Pro module of Pro/Engineer software, including mechanism modeling, driving control, and so on. The motion simulation of the whole head mechanism is executed, the simulation results are analyzed and show the feasibility and rationality of developed head mechanism, The head mechanism has been successfully used to the LED die bonding machine with desired functions and performances.
In order to develop a bonding head mechanism with high-speed and high-precision characteristics and ensure the whole machine performance of automatic LED die bonders. A motion proposal and structure parameters of the head mechanism are designed, the motion modeling technologies and methods of the whole head mechanism are researched by using the Mechanism/Pro module of Pro/Engineer software, including mechanism modeling, driving control, and so on. The motion simulation of the whole head mechanism is executed, the simulation results are analyzed and show the feasibility and rationality of developed head mechanism, The head mechanism has been successfully used to the LED die bonding machine with desired functions and performances.
