ISSN 
2010 Vol. 39, No. 2
2010, 39(2): 161-163.
doi: 10.3969/j.issn.1001-0548.2010.02.001
Abstract:
A novel waveguide-microstrip back to back transition structure by utilizing Quasi-yagi Antenna is introducted in this paper. By adopting high dielectric substrate and adding numbers of the Yagi antenna director, electromagnetic coupling effect between antenna and waveguide is improved to make a smoother transition in passband. Compared with traditional waveguide-microstrip structure, it has a advantagment of wider bandwidth (nearly 68%). Through electromagnetic software CST, a full-wave analysis in the whole X-band bring about better S21(S210.7 dB). The a toralance Analysis to this transition structure Shows that S21 still keeps fine consistency and comparatively low insert loss within deviation of 10%, which can meet the requirement of production.
A novel waveguide-microstrip back to back transition structure by utilizing Quasi-yagi Antenna is introducted in this paper. By adopting high dielectric substrate and adding numbers of the Yagi antenna director, electromagnetic coupling effect between antenna and waveguide is improved to make a smoother transition in passband. Compared with traditional waveguide-microstrip structure, it has a advantagment of wider bandwidth (nearly 68%). Through electromagnetic software CST, a full-wave analysis in the whole X-band bring about better S21(S210.7 dB). The a toralance Analysis to this transition structure Shows that S21 still keeps fine consistency and comparatively low insert loss within deviation of 10%, which can meet the requirement of production.
2010, 39(2): 164-168.
doi: 10.3969/j.issn.1001-0548.2010.02.002
Abstract:
A new approach to the range-independence frequency scaling (FS) factor of translational invariant bistatic synthetic aperture radar (SAR) is presented to solve the problem that the range cell movement (RCM) of bistatic SAR is influenced by transmitter and receiver range histories. The change of the RCM with two dimensional ranges is translated into that with one dimensional range, so the independent FS factor is acquired with the linear approximation of range migration. And based on this new approach, the FS algorithm is extended into translational invariant bistatic SAR. Finally, the new approach is validated by point target simulations.
A new approach to the range-independence frequency scaling (FS) factor of translational invariant bistatic synthetic aperture radar (SAR) is presented to solve the problem that the range cell movement (RCM) of bistatic SAR is influenced by transmitter and receiver range histories. The change of the RCM with two dimensional ranges is translated into that with one dimensional range, so the independent FS factor is acquired with the linear approximation of range migration. And based on this new approach, the FS algorithm is extended into translational invariant bistatic SAR. Finally, the new approach is validated by point target simulations.
2010, 39(2): 169-172.
doi: 10.3969/j.issn.1001-0548.2010.02.003
Abstract:
Based on the Reynolds-averaged N-S equations and Reynolds stress equation model (RSM), the numerical simulation is performed on a vehicle-mounted radar antenna. In the simulation, the inlet boundary type is defined as velocity inlet with wind velocity section in specified exposure category. The drag coefficients of the antenna are obtained and compared with the results of computational models in which the boundary velocity is uniform velocity. The effects of working height and wind velocity on the antenna characteristics of antenna in atmospheric boundary layer are studied. The results show that the drag coefficients of antennas will be increased along with the working height and wind velocity, and the effect of the ground roughness to the drag coefficients is decided by the position relative to the normal height.
Based on the Reynolds-averaged N-S equations and Reynolds stress equation model (RSM), the numerical simulation is performed on a vehicle-mounted radar antenna. In the simulation, the inlet boundary type is defined as velocity inlet with wind velocity section in specified exposure category. The drag coefficients of the antenna are obtained and compared with the results of computational models in which the boundary velocity is uniform velocity. The effects of working height and wind velocity on the antenna characteristics of antenna in atmospheric boundary layer are studied. The results show that the drag coefficients of antennas will be increased along with the working height and wind velocity, and the effect of the ground roughness to the drag coefficients is decided by the position relative to the normal height.
2010, 39(2): 173-175,181.
doi: 10.3969/j.issn.1001-0548.2010.02.004
Abstract:
To increase the capacity and link performance of mobile communications, it is important to accurately estimate the powers and directions of arrival (DOA) of sources. A multi-dimension nonlinear cost function is proposed for this purpose, where the DOAs and powers of sources are optimization parameters. The optimal results are obtained with the Davidson-Fletcher-Powell (DFP) algorithm and are compared with the results of alternating projection (AP) algorithm. The simulation results show that DFP has the accuracy in accordance with AP when sources are away from each other, but higher than AP when sources are near.
To increase the capacity and link performance of mobile communications, it is important to accurately estimate the powers and directions of arrival (DOA) of sources. A multi-dimension nonlinear cost function is proposed for this purpose, where the DOAs and powers of sources are optimization parameters. The optimal results are obtained with the Davidson-Fletcher-Powell (DFP) algorithm and are compared with the results of alternating projection (AP) algorithm. The simulation results show that DFP has the accuracy in accordance with AP when sources are away from each other, but higher than AP when sources are near.
2010, 39(2): 176-181,175.
doi: 10.3969/j.issn.1001-0548.2010.02.005
Abstract:
A new method for modeling moving and perfectly conducting objects is proposed using a numerical technique based on the finite-difference time domain (FD-TD) method. Contrary to any other method, the numerical technique used does not require a coordinate transformation, the linear interpolation for the value of the incident field at the interface between the two different materials, and the determining of the position of the total field. This leads to saving calculation amount and CPU time. The electromagnetic wave scattering properties of a moving and perfectly conducting surface are analyzed using the numerical technique. Results obtained are given to show the high accuracy and efficiency of this new technique.
A new method for modeling moving and perfectly conducting objects is proposed using a numerical technique based on the finite-difference time domain (FD-TD) method. Contrary to any other method, the numerical technique used does not require a coordinate transformation, the linear interpolation for the value of the incident field at the interface between the two different materials, and the determining of the position of the total field. This leads to saving calculation amount and CPU time. The electromagnetic wave scattering properties of a moving and perfectly conducting surface are analyzed using the numerical technique. Results obtained are given to show the high accuracy and efficiency of this new technique.
2010, 39(2): 182-185.
doi: 10.3969/j.issn.1001-0548.2010.02.006
Abstract:
Radar emitter identification algorithm based on fuzzy theory is improved. By analyzing fuzzy subordinate values and then using evidence combination principle to combine these values, the recognition uncertainty is solved. The class decision-making is carried out based on optimization subordinate rule, the accurate recognition rate is increased. Simulation experiment shows that new algorithm identification rate more than 90% when SNR higher than 0 dB compared with fuzzy identification method.
Radar emitter identification algorithm based on fuzzy theory is improved. By analyzing fuzzy subordinate values and then using evidence combination principle to combine these values, the recognition uncertainty is solved. The class decision-making is carried out based on optimization subordinate rule, the accurate recognition rate is increased. Simulation experiment shows that new algorithm identification rate more than 90% when SNR higher than 0 dB compared with fuzzy identification method.
2010, 39(2): 186-190.
doi: 10.3969/j.issn.1001-0548.2010.02.007
Abstract:
In blind speech separation methods based on the assumption of W-disjoint orthogonality (W-DO), musical noise is inevitable in separated signals because the assumption does not include the case of existing multiple source signals in the time-frequency domain. A blind speech separation method based on channel estimation is proposed for partial approximate W-disjoint orthogonality. The time-frequency cells with only one source are detected and normalized to be independent of frequency, which overcomes not only the shortcoming of W-DO property but also the frequency permutation problem, and then the channel estimation is obtained by K-means clustering. Finally, signal subspace method is exploited to reconstruct sources. Simulation results demonstrate that the novel method can effectively reduce the musical noise in the separated speech signals, and it outperforms the typical time frequency binary masking method, the averaged signal to distortion ratio (SDR) is improved by 3.02 dB and the averaged signal to interference ratio (SIR) is improved by 4.61 dB.
In blind speech separation methods based on the assumption of W-disjoint orthogonality (W-DO), musical noise is inevitable in separated signals because the assumption does not include the case of existing multiple source signals in the time-frequency domain. A blind speech separation method based on channel estimation is proposed for partial approximate W-disjoint orthogonality. The time-frequency cells with only one source are detected and normalized to be independent of frequency, which overcomes not only the shortcoming of W-DO property but also the frequency permutation problem, and then the channel estimation is obtained by K-means clustering. Finally, signal subspace method is exploited to reconstruct sources. Simulation results demonstrate that the novel method can effectively reduce the musical noise in the separated speech signals, and it outperforms the typical time frequency binary masking method, the averaged signal to distortion ratio (SDR) is improved by 3.02 dB and the averaged signal to interference ratio (SIR) is improved by 4.61 dB.
2010, 39(2): 191-195.
doi: 10.3969/j.issn.1001-0548.2010.02.008
Abstract:
The characteristic of residuary bit errors in satellite baseband channel affects the performance of communication protocol in upper layers significantly. By system simulation and analyzing the bit error patterns, the probability distribution function (PDF) of bit errors occurrence and PDF of bit errors length are obtained. In typical satellite communication systems against the Rician fading channel, the PDF of bit errors occurrence approximates generalized extreme value distribution. But in Gaussian noise channel, the PDFs of bit errors occurrence and bit errors length approximate negative binomial distributions. Base on these fitting distributions, the baseband channel emulator provides a convenient method for system testing, which imposes residuary bit errors pattern on data stream reasonably.
The characteristic of residuary bit errors in satellite baseband channel affects the performance of communication protocol in upper layers significantly. By system simulation and analyzing the bit error patterns, the probability distribution function (PDF) of bit errors occurrence and PDF of bit errors length are obtained. In typical satellite communication systems against the Rician fading channel, the PDF of bit errors occurrence approximates generalized extreme value distribution. But in Gaussian noise channel, the PDFs of bit errors occurrence and bit errors length approximate negative binomial distributions. Base on these fitting distributions, the baseband channel emulator provides a convenient method for system testing, which imposes residuary bit errors pattern on data stream reasonably.
2010, 39(2): 196-200,208.
doi: 10.3969/j.issn.1001-0548.2010.02.009
Abstract:
The relationship between the game players in wireless communication countermeasures is studied in this paper. Based on analysis of hierarchy process (AHP), a set of indicators for wireless communication system evaluation in adverse electromagnetism environment are constructed. Furthermore, an evaluating model for appraising the anti-jamming effectiveness of wireless communication system is provided. Through normalization processing, the basic elements of wireless communication, the anti-jamming ability of wireless communication system in various countermeasures conditions could be appraised by using this model. Simulation shows the validity of improving the integrated anti-jamming capability of the system through combining the evaluation model and jamming detection method.
The relationship between the game players in wireless communication countermeasures is studied in this paper. Based on analysis of hierarchy process (AHP), a set of indicators for wireless communication system evaluation in adverse electromagnetism environment are constructed. Furthermore, an evaluating model for appraising the anti-jamming effectiveness of wireless communication system is provided. Through normalization processing, the basic elements of wireless communication, the anti-jamming ability of wireless communication system in various countermeasures conditions could be appraised by using this model. Simulation shows the validity of improving the integrated anti-jamming capability of the system through combining the evaluation model and jamming detection method.
2010, 39(2): 200-203.
doi: 10.3969/j.issn.1001-0548.2010.02.010
Abstract:
A novel and efficient fusion method for polarimetric SAR image based on stationary contourlet transform is proposed. Several single-polarimetric-channel SAR intensity images are decomposed using stationary contourlet transform. Low-pass coefficients and the directional high-frequency coefficients are selected by optimal weighted sum of intensities algorithm for fusion. Experimental results show that compared with PWF de-speckling algorithm, the proposed algorithm can get better visual effect and preserves image details, and the significant information of original image like textures and contour details is well maintained.
A novel and efficient fusion method for polarimetric SAR image based on stationary contourlet transform is proposed. Several single-polarimetric-channel SAR intensity images are decomposed using stationary contourlet transform. Low-pass coefficients and the directional high-frequency coefficients are selected by optimal weighted sum of intensities algorithm for fusion. Experimental results show that compared with PWF de-speckling algorithm, the proposed algorithm can get better visual effect and preserves image details, and the significant information of original image like textures and contour details is well maintained.
2010, 39(2): 204-208,199.
doi: 10.3969/j.issn.1001-0548.2010.02.011
Abstract:
The new DHx packets are adopted in Bluetooth 2.0+EDR specification. Without any error correction coding mechanism, it has poor anti-interference ability in the burst errors channel. To enhance the data transmission throughput and anti-interference ability efficiently, a method by introducing new packets with BCH codes and interleaving to the Bluetooth 2.0+EDR specification is proposed. The packet properties of new packets are deduced based on the packet definition of Bluetooth specification. An analytical model of the throughput in different burst error cases is presented under the Gillbert-Elliott(GE) channel, the throughput of different packets in different burst error cases are obtained. The simulation result shows that adding new packets with BCH codes and interleaving to Bluetooth 2.0+EDR specification can improve the anti-interference ability and the data transmission throughput increases more than 100% in the higher burst errors channel.
The new DHx packets are adopted in Bluetooth 2.0+EDR specification. Without any error correction coding mechanism, it has poor anti-interference ability in the burst errors channel. To enhance the data transmission throughput and anti-interference ability efficiently, a method by introducing new packets with BCH codes and interleaving to the Bluetooth 2.0+EDR specification is proposed. The packet properties of new packets are deduced based on the packet definition of Bluetooth specification. An analytical model of the throughput in different burst error cases is presented under the Gillbert-Elliott(GE) channel, the throughput of different packets in different burst error cases are obtained. The simulation result shows that adding new packets with BCH codes and interleaving to Bluetooth 2.0+EDR specification can improve the anti-interference ability and the data transmission throughput increases more than 100% in the higher burst errors channel.
2010, 39(2): 209-213,226.
doi: 10.3969/j.issn.1001-0548.2010.02.012
Abstract:
An effective method for strong noise pollution control in multiple copy images is proposed. If the noise and original image are mutually independent in mixed signals, the mixed signals are decomposed to an original image component and a noise component using ICA. The original image component is selected to reconstruct the result image according to standard deviation of its time course. Experimental results show that the proposed method can separate nonzero-mean noise Gaussian noise from multiple copy images, and is effective in the case of stable and unstable noise intensity.
An effective method for strong noise pollution control in multiple copy images is proposed. If the noise and original image are mutually independent in mixed signals, the mixed signals are decomposed to an original image component and a noise component using ICA. The original image component is selected to reconstruct the result image according to standard deviation of its time course. Experimental results show that the proposed method can separate nonzero-mean noise Gaussian noise from multiple copy images, and is effective in the case of stable and unstable noise intensity.
2010, 39(2): 214-218.
doi: 10.3969/j.issn.1001-0548.2010.02.013
Abstract:
Different from Turbo codes, product codes have no error floor problem and have better performance at high rate. In the recent year, product codes are widely used. Parity check product codes, which have the simpler decoding algorithm, can adapt to different required data length. Its performance formula is proposed after analyzing the code multiplicity and information multiplicity. Computer simulations show that the performance of the formula is the same as that of maximum likelihood(ML) decoding algorithm and iterative decoding algorithm. Performance analysis, which is based on different parameters such as code rate, dimension, and code length, shows that multidimensional parity check product codes have close performance at same code rate and dimension, and the codes with higher dimension can get better performance at same code rate.
Different from Turbo codes, product codes have no error floor problem and have better performance at high rate. In the recent year, product codes are widely used. Parity check product codes, which have the simpler decoding algorithm, can adapt to different required data length. Its performance formula is proposed after analyzing the code multiplicity and information multiplicity. Computer simulations show that the performance of the formula is the same as that of maximum likelihood(ML) decoding algorithm and iterative decoding algorithm. Performance analysis, which is based on different parameters such as code rate, dimension, and code length, shows that multidimensional parity check product codes have close performance at same code rate and dimension, and the codes with higher dimension can get better performance at same code rate.
2010, 39(2): 219-222.
doi: 10.3969/j.issn.1001-0548.2010.02.014
Abstract:
The simple algorithms based on belief propagation algorithm of LDPC codes are studied. A modified algorithm which integrates Row Message Passing schedule with Offset Min-Sum algorithm for decoding LDPC codes is proposed. The proposed algorithm facilitates hardware implementation because it improves the convergence property while its computation complexity is the same as Offset Min-Sum algorithm, and it reduces the storage for the optimized memory method. The simulation results demonstrate that the proposed algorithm reduces the average iterations and quantization implementation memory.
The simple algorithms based on belief propagation algorithm of LDPC codes are studied. A modified algorithm which integrates Row Message Passing schedule with Offset Min-Sum algorithm for decoding LDPC codes is proposed. The proposed algorithm facilitates hardware implementation because it improves the convergence property while its computation complexity is the same as Offset Min-Sum algorithm, and it reduces the storage for the optimized memory method. The simulation results demonstrate that the proposed algorithm reduces the average iterations and quantization implementation memory.
2010, 39(2): 223-226,213.
doi: 10.3969/j.issn.1001-0548.2010.02.015
Abstract:
For miniaturization and harmonic suppression, a novel planar compact lowpass filter is presented in this paper. A conventional stepped-impedance lowpass filter is modified by some microstrip steps connected in 90° and some T-shaped transmission lines integrated into the lowpass filter. The proposed lowpass filter has the advantage of low insertion loss (below 0.5 dB at 0～4 GHz), ultra broad stopband (over 40 dB at 5～30 GHz) and compact size (50% reduction). Experiment validates the design concept.
For miniaturization and harmonic suppression, a novel planar compact lowpass filter is presented in this paper. A conventional stepped-impedance lowpass filter is modified by some microstrip steps connected in 90° and some T-shaped transmission lines integrated into the lowpass filter. The proposed lowpass filter has the advantage of low insertion loss (below 0.5 dB at 0～4 GHz), ultra broad stopband (over 40 dB at 5～30 GHz) and compact size (50% reduction). Experiment validates the design concept.
2010, 39(2): 227-231,250.
doi: 10.3969/j.issn.1001-0548.2010.02.016
Abstract:
Continuous wave (CW) telegraph is a crucial communication means for high-frequency tactical communication in emergencies. But there exists serious decline in high-frequency channel, thus the statistical properties of interference noise can not be known in advance. A new adaptive Kalman filter based on autoregressive moving average (ARMA) innovation model is proposed in this paper to detect weak high-frequency CW signal with unknown precise statistical variance of Gaussian noise in system. The state space random signal model of CW signal is firstly defined, by which the ARMA innovation model is constructed. Then by means of the on-line identification of ARMA model parameters, the Kalman filter gain is estimated to implement the adpative Kalman filtering of CW signal. Simulation studies show this method can dynamically track weak CW signal with unknown variance of Gaussian interference noise.
Continuous wave (CW) telegraph is a crucial communication means for high-frequency tactical communication in emergencies. But there exists serious decline in high-frequency channel, thus the statistical properties of interference noise can not be known in advance. A new adaptive Kalman filter based on autoregressive moving average (ARMA) innovation model is proposed in this paper to detect weak high-frequency CW signal with unknown precise statistical variance of Gaussian noise in system. The state space random signal model of CW signal is firstly defined, by which the ARMA innovation model is constructed. Then by means of the on-line identification of ARMA model parameters, the Kalman filter gain is estimated to implement the adpative Kalman filtering of CW signal. Simulation studies show this method can dynamically track weak CW signal with unknown variance of Gaussian interference noise.
2010, 39(2): 232-235.
doi: 10.3969/j.issn.1001-0548.2010.02.017
Abstract:
In millimeter and sub-millimeter wave bands, the multiplying method using semiconductor devices has been playing an increasing important role in accessing solid state signal source. In this paper, the circuit topology is designed by using computer aided design (CAD) technology. The study mainly includs the analysis of impedance-frequency characteristics of diodes by harmonious balance method, the simulation of the best bias point of the circuit, and design of the input and output matching circuits. Finally, the whole passive 185 GHz doubler is simulated and optimized by the commercial software aglient advanced design system (ADS) and ansoft high frequency structure simulator (HFSS). The frequency doubler has been fabricated and measured. The measured results show that the 185 GHz signal is obtained successfully with a minimum loss of 16.8 dB and a maximum loss of 22 dB.
In millimeter and sub-millimeter wave bands, the multiplying method using semiconductor devices has been playing an increasing important role in accessing solid state signal source. In this paper, the circuit topology is designed by using computer aided design (CAD) technology. The study mainly includs the analysis of impedance-frequency characteristics of diodes by harmonious balance method, the simulation of the best bias point of the circuit, and design of the input and output matching circuits. Finally, the whole passive 185 GHz doubler is simulated and optimized by the commercial software aglient advanced design system (ADS) and ansoft high frequency structure simulator (HFSS). The frequency doubler has been fabricated and measured. The measured results show that the 185 GHz signal is obtained successfully with a minimum loss of 16.8 dB and a maximum loss of 22 dB.
2010, 39(2): 236-241.
doi: 10.3969/j.issn.1001-0548.2010.02.018
Abstract:
To provide credible services and facilitate the development of applications for the distributed real-time embedded system (DRES), a credible service component model, QUOCCM, is proposed. By QUOCCM, a DRES application is separated into two parts: function realization and performance guarantee. The latter is encapsulated into some components to provide common services for the former. Specially, QUOCCM can provide an adaptive service support about application performance running in the dynamic environment. Finally, a flight control system in DRES has been used to confirm the feasibility and flexibility of the model.
To provide credible services and facilitate the development of applications for the distributed real-time embedded system (DRES), a credible service component model, QUOCCM, is proposed. By QUOCCM, a DRES application is separated into two parts: function realization and performance guarantee. The latter is encapsulated into some components to provide common services for the former. Specially, QUOCCM can provide an adaptive service support about application performance running in the dynamic environment. Finally, a flight control system in DRES has been used to confirm the feasibility and flexibility of the model.
2010, 39(2): 242-246.
doi: 10.3969/j.issn.1001-0548.2010.02.019
Abstract:
A fuzzy assessment system of Web resource quality is implemented. The system functions include Web sources investigation and comparison, criteria determination, Web sources evaluation, and sensitivity analysis of the criteria. Fuzzy logic and multi-attributes decision making (MADM) methods are integrated for tackling the incompleteness, imprecision, uncertainty, and subjectivity in the Web quality quantization and assessment. The sensitivity analysis and the quality ranking of Web sources are used by evaluators to better quantize Web source quality and to improve the fuzzy evaluation procedure for obtaining more precise results and for selecting more qualified Web sources.
A fuzzy assessment system of Web resource quality is implemented. The system functions include Web sources investigation and comparison, criteria determination, Web sources evaluation, and sensitivity analysis of the criteria. Fuzzy logic and multi-attributes decision making (MADM) methods are integrated for tackling the incompleteness, imprecision, uncertainty, and subjectivity in the Web quality quantization and assessment. The sensitivity analysis and the quality ranking of Web sources are used by evaluators to better quantize Web source quality and to improve the fuzzy evaluation procedure for obtaining more precise results and for selecting more qualified Web sources.
2010, 39(2): 247-250,231.
doi: 10.3969/j.issn.1001-0548.2010.02.020
Abstract:
Eye detection plays a very important role in the face recognition. This paper expands a Haar features by using Adaboost algorithm to accurately detect the eye. By combining an extremely efficient classifier based on Adaboost algorithm, the wide outlines of eye and eyebrow are detected, and then the templates of these wide doutlines are formed. Finally, these templates are used to match the pictures with eyes and eyebrow. Result shows that the wrong judgement due to the similitude of the eyes and eyebrow can be avoided.
Eye detection plays a very important role in the face recognition. This paper expands a Haar features by using Adaboost algorithm to accurately detect the eye. By combining an extremely efficient classifier based on Adaboost algorithm, the wide outlines of eye and eyebrow are detected, and then the templates of these wide doutlines are formed. Finally, these templates are used to match the pictures with eyes and eyebrow. Result shows that the wrong judgement due to the similitude of the eyes and eyebrow can be avoided.
2010, 39(2): 251-254,259.
doi: 10.3969/j.issn.1001-0548.2010.02.021
Abstract:
By analyzing and studying four main checkout technologies of redundant array of independent disks (RAID), 6D+2P checkout technology is proposed based on P+Q checkout technology. 6D+2P checkout technology can effectively deal with data recovery when two disks are wrong. The main principle is that it distracts the application data and checkout data into eight disks from one RAID group, thus can ensure the read-write performance and the data security. Experimental results verified that the use ratio and read-write capability of disk array based on 6D+2P are improved effectively, where the use ratio can up to 85%.
By analyzing and studying four main checkout technologies of redundant array of independent disks (RAID), 6D+2P checkout technology is proposed based on P+Q checkout technology. 6D+2P checkout technology can effectively deal with data recovery when two disks are wrong. The main principle is that it distracts the application data and checkout data into eight disks from one RAID group, thus can ensure the read-write performance and the data security. Experimental results verified that the use ratio and read-write capability of disk array based on 6D+2P are improved effectively, where the use ratio can up to 85%.
2010, 39(2): 255-259,254.
doi: 10.3969/j.issn.1001-0548.2010.02.022
Abstract:
This paper presents a new method to develop the interconnection and intercommunication control center, which usually plays a central server role in a digital home system. The proposed method adopts several novel technologies, such as bi-directional digital set-top-box, component technology, and design patterns. Moreover, this paper gives an intelligent component container programming model, and implements a central server for digital home system by utilizing such a model on Linux platform. Simulation experiments show that this method can promote software development efficiency, and provide a feasible solution for designing a central server of digital home.
This paper presents a new method to develop the interconnection and intercommunication control center, which usually plays a central server role in a digital home system. The proposed method adopts several novel technologies, such as bi-directional digital set-top-box, component technology, and design patterns. Moreover, this paper gives an intelligent component container programming model, and implements a central server for digital home system by utilizing such a model on Linux platform. Simulation experiments show that this method can promote software development efficiency, and provide a feasible solution for designing a central server of digital home.
2010, 39(2): 260-265.
doi: 10.3969/j.issn.1001-0548.2010.02.023
Abstract:
A fuzzy TCP congestion control algorithm is proposed. The algorithm achieves better evaluation on network congestion by the way of combining the current and historical RTT changes which are used to adjust congestion window (CWND) with fuzzy controller, so that the problem of low throughput under abrupt congestion situations is solved effectively. The performance of the algorithm has been tested and evaluated on NS simulator and the simulation results demonstrate that the algorithm inspects network congestion more exactly and accordingly increases network throughput.
A fuzzy TCP congestion control algorithm is proposed. The algorithm achieves better evaluation on network congestion by the way of combining the current and historical RTT changes which are used to adjust congestion window (CWND) with fuzzy controller, so that the problem of low throughput under abrupt congestion situations is solved effectively. The performance of the algorithm has been tested and evaluated on NS simulator and the simulation results demonstrate that the algorithm inspects network congestion more exactly and accordingly increases network throughput.
2010, 39(2): 266-270,292.
doi: 10.3969/j.issn.1001-0548.2010.02.024
Abstract:
Accurate knowledge of the autonomous system (AS) commercial relationships will contribute to research Internet structure and network behaviors intensively. Usually the AS relationships are obtained only by inference. Several algorithms on AS relationships inference are summarized and their advantages and disadvantages are discussed. A new metric is defined, which represents the transmission capability of an AS node based on its routing behaviors. The metric is more suitable to describe the level of AS nodes on transmission capability than the node degree. Based on the metric, a quick inference algorithm is presented which infers AS relationships by comparing the level of nodes. The experiment results show this algorithm has good consistency with Dimitropolous’s algorithm on the inference results, and the basic AS relationships can be inferred quickly and efficiently by this algorithm.
Accurate knowledge of the autonomous system (AS) commercial relationships will contribute to research Internet structure and network behaviors intensively. Usually the AS relationships are obtained only by inference. Several algorithms on AS relationships inference are summarized and their advantages and disadvantages are discussed. A new metric is defined, which represents the transmission capability of an AS node based on its routing behaviors. The metric is more suitable to describe the level of AS nodes on transmission capability than the node degree. Based on the metric, a quick inference algorithm is presented which infers AS relationships by comparing the level of nodes. The experiment results show this algorithm has good consistency with Dimitropolous’s algorithm on the inference results, and the basic AS relationships can be inferred quickly and efficiently by this algorithm.
2010, 39(2): 271-274.
doi: 10.3969/j.issn.1001-0548.2010.02.025
Abstract:
QoS routing problem is proved to be a NP-C problem, it is very difficult to solve the NP-C problem effectively by conventional routing algorithms. This paper puts forward an QoS unicast routing algorithm which is based on the principle of ant colony algorithm and used to solve the problem of bandwidth and delay constrain. The rule of ant colony algorithm that the ants find the shortest path through the laying down of pheromone and the rule with emphasis on the maximal network throughput and the lowest average cell delay are also used to define the transition probability of ants, routing table, and the way pheromone is updated. A detailed routing scheme algorithm based on the ant colony algorithm is implemented. Results prove that the algorithm has strong ability of searching an optimum solution and show its better flexibility and potential parallelism.
QoS routing problem is proved to be a NP-C problem, it is very difficult to solve the NP-C problem effectively by conventional routing algorithms. This paper puts forward an QoS unicast routing algorithm which is based on the principle of ant colony algorithm and used to solve the problem of bandwidth and delay constrain. The rule of ant colony algorithm that the ants find the shortest path through the laying down of pheromone and the rule with emphasis on the maximal network throughput and the lowest average cell delay are also used to define the transition probability of ants, routing table, and the way pheromone is updated. A detailed routing scheme algorithm based on the ant colony algorithm is implemented. Results prove that the algorithm has strong ability of searching an optimum solution and show its better flexibility and potential parallelism.
2010, 39(2): 275-278,310.
doi: 10.3969/j.issn.1001-0548.2010.02.026
Abstract:
In order to reduce the limit of time synchronization and cooperation between nodes, a measurement method named “transport train” is proposed. The measurement method could measure the queue delay of share links between nodes. by using only one measuring node and without need of time synchronization, A topology inference algorithm is put forward based on queue delay. The feasibility and correctness of topology inference algorithm based on queue delay and “transport train” measurement method are analyzed theoretically. The algorithm is simulated by NS2, the results validate that topology inference algorithm based on queue delay and “transport train” measurement method could infer network topology correctly.
In order to reduce the limit of time synchronization and cooperation between nodes, a measurement method named “transport train” is proposed. The measurement method could measure the queue delay of share links between nodes. by using only one measuring node and without need of time synchronization, A topology inference algorithm is put forward based on queue delay. The feasibility and correctness of topology inference algorithm based on queue delay and “transport train” measurement method are analyzed theoretically. The algorithm is simulated by NS2, the results validate that topology inference algorithm based on queue delay and “transport train” measurement method could infer network topology correctly.
2010, 39(2): 279-283.
doi: 10.3969/j.issn.1001-0548.2010.02.027
Abstract:
To cope with the problem of controlling population diversity in gene expression programming (GEP), an adaptive population diversity tuning algorithm is proposed. A weighted measurement for population diversity is designed. The impact in terms of selection, crossover, and mutation operators on population diversity is analyzed in detail. A diversity algorithm for initial population (DAIP) maximizing the initial population diversity is proposed as well. Aiming to appropriately maintain the population diversity and achieve high evolution efficiency, adaptive crossover and mutation operations are developed and an adaptive population diversity tuning algorithm (APDTA) is developed. Experiments show that APDTA is efficient and effective.
To cope with the problem of controlling population diversity in gene expression programming (GEP), an adaptive population diversity tuning algorithm is proposed. A weighted measurement for population diversity is designed. The impact in terms of selection, crossover, and mutation operators on population diversity is analyzed in detail. A diversity algorithm for initial population (DAIP) maximizing the initial population diversity is proposed as well. Aiming to appropriately maintain the population diversity and achieve high evolution efficiency, adaptive crossover and mutation operations are developed and an adaptive population diversity tuning algorithm (APDTA) is developed. Experiments show that APDTA is efficient and effective.
2010, 39(2): 284-288,310.
doi: 10.3969/j.issn.1001-0548.2010.02.028
Abstract:
Gene Expression Programming (GEP) is a new member of evolutionary algorithm family, and it is an artificial genotype/phenotype system. Aiming to discover compact mathematical functions for function finding, this study analyzes the factors that greatly affect the efficiency of GEP, proposes the fitness function with pressure parameter, and implements a naïve gene expression programming (NGEP) for compact function mining tasks. Extensive experiments show that the proposed fitness function with compact pressure can automatically mine the compact functions as well as an alternative strategy to find compact results, and NGEP boosts the convergence speed by 21.7% than GEP, in addition, the results are more understandable than that are found by GEP. Compared with the evolution system without compact pressure, the average compact rate are 31.2% in GEP and 42.5% in NGEP, respectively, which shows that NGEP is easier to find compact results than GEP and the results are more comprehensive than traditional GEP.
Gene Expression Programming (GEP) is a new member of evolutionary algorithm family, and it is an artificial genotype/phenotype system. Aiming to discover compact mathematical functions for function finding, this study analyzes the factors that greatly affect the efficiency of GEP, proposes the fitness function with pressure parameter, and implements a naïve gene expression programming (NGEP) for compact function mining tasks. Extensive experiments show that the proposed fitness function with compact pressure can automatically mine the compact functions as well as an alternative strategy to find compact results, and NGEP boosts the convergence speed by 21.7% than GEP, in addition, the results are more understandable than that are found by GEP. Compared with the evolution system without compact pressure, the average compact rate are 31.2% in GEP and 42.5% in NGEP, respectively, which shows that NGEP is easier to find compact results than GEP and the results are more comprehensive than traditional GEP.
2010, 39(2): 289-292,270.
doi: 10.3969/j.issn.1001-0548.2010.02.029
Abstract:
Aiming at the problem of inaccurate and discordant arithmetic caused by informal software specification, this paper puts forward an OUVE (OCL-based UML verification environment) setting which is based on Object Constraint Language. OUVE can verify whether the constraints and relationship among classes correspond with practical requirements before coding. Comparing with traditional method, OUVE reduces the cost of modification caused by improper design and programming fault.
Aiming at the problem of inaccurate and discordant arithmetic caused by informal software specification, this paper puts forward an OUVE (OCL-based UML verification environment) setting which is based on Object Constraint Language. OUVE can verify whether the constraints and relationship among classes correspond with practical requirements before coding. Comparing with traditional method, OUVE reduces the cost of modification caused by improper design and programming fault.
2010, 39(2): 293-297.
doi: 10.3969/j.issn.1001-0548.2010.02.030
Abstract:
TTM is a type of Multivariate public key cryptosystem. By analyzing the instance of TTM proposed in 2004, it can be found that there are many first order linearization equations satisfied by the cipher in this scheme. For a given public key, all first order linearization equations can be found through precomputation. For any given ciphertext, the corresponding plaintext can be found in less than 219 operations over a finite field of size 28 by linearization equation attack. This attack reduced complexity of recovering plaintext from 231 to 219 compare to second order linearization equation attack. The results above are further confirmed by computer experiments.
TTM is a type of Multivariate public key cryptosystem. By analyzing the instance of TTM proposed in 2004, it can be found that there are many first order linearization equations satisfied by the cipher in this scheme. For a given public key, all first order linearization equations can be found through precomputation. For any given ciphertext, the corresponding plaintext can be found in less than 219 operations over a finite field of size 28 by linearization equation attack. This attack reduced complexity of recovering plaintext from 231 to 219 compare to second order linearization equation attack. The results above are further confirmed by computer experiments.
2010, 39(2): 298-301,315.
doi: 10.3969/j.issn.1001-0548.2010.02.031
Abstract:
In the process of GIS service chaining, the quality of service (QoS), as well as functionality of service, is very essential for Web GIS users. Nevertheless, OGC standards for GIS services have not yet supported QoS currently. This paper proposes a QoS extension to OGC interoperation specifications related to GIS services as well as an optimal approach of GIS web service chaining with global QoS constraints. This constrained optimization question is solved using a genetic algorithm with a penalty-based fitness function and a tree coding structure modeling the flowchart of GIS service chaining. With an experimental example, the effectiveness of this approach is verified in comparison with Integer programming method. By changing examination conditions such as the number of candidate services or task nodes, it is found that this approach has near linear time complexity.
In the process of GIS service chaining, the quality of service (QoS), as well as functionality of service, is very essential for Web GIS users. Nevertheless, OGC standards for GIS services have not yet supported QoS currently. This paper proposes a QoS extension to OGC interoperation specifications related to GIS services as well as an optimal approach of GIS web service chaining with global QoS constraints. This constrained optimization question is solved using a genetic algorithm with a penalty-based fitness function and a tree coding structure modeling the flowchart of GIS service chaining. With an experimental example, the effectiveness of this approach is verified in comparison with Integer programming method. By changing examination conditions such as the number of candidate services or task nodes, it is found that this approach has near linear time complexity.
2010, 39(2): 302-305.
doi: 10.3969/j.issn.1001-0548.2010.02.032
Abstract:
The notion of sequence itemset is introduced for algorithm to deal with permutations items or transactions of itemsets. A recursive method is provided to generate signatures with different length in turn. The algorithm utilizes offset attributor set to restrict and remove ineffective itemsets. According to selection principle, the optimal constrained frequency sequence itemset as signatures can be found. The result shows that the signatures extracted by this algorithm are reasonable and effective.
The notion of sequence itemset is introduced for algorithm to deal with permutations items or transactions of itemsets. A recursive method is provided to generate signatures with different length in turn. The algorithm utilizes offset attributor set to restrict and remove ineffective itemsets. According to selection principle, the optimal constrained frequency sequence itemset as signatures can be found. The result shows that the signatures extracted by this algorithm are reasonable and effective.
2010, 39(2): 306-310,278.
doi: 10.3969/j.issn.1001-0548.2010.02.033
Abstract:
The high efficient very large scale integration (VSLI) implementation of scaling operation for residue number system (RNS) plays an important role in RNS-based digital signal processing (DSP) systems. In this paper, the general algorithm for scaling a positive number in RNS is presented firstly. With the properties of moduli set {2n-1, 2n, 2n+1} and based on the proposed scaling algorithm, an efficient 2n scaling scheme for this moduli set is proposed. Furthermore, the correction factor for negative numbers scaling is also presented. The analysis result shows that the proposed scaler has higher area and power consumption performances compared with the cascaded scaling scheme. The scaler can be used in the design of RNS-based DSP systems.
The high efficient very large scale integration (VSLI) implementation of scaling operation for residue number system (RNS) plays an important role in RNS-based digital signal processing (DSP) systems. In this paper, the general algorithm for scaling a positive number in RNS is presented firstly. With the properties of moduli set {2n-1, 2n, 2n+1} and based on the proposed scaling algorithm, an efficient 2n scaling scheme for this moduli set is proposed. Furthermore, the correction factor for negative numbers scaling is also presented. The analysis result shows that the proposed scaler has higher area and power consumption performances compared with the cascaded scaling scheme. The scaler can be used in the design of RNS-based DSP systems.
2010, 39(2): 311-315,301.
doi: 10.3969/j.issn.1001-0548.2010.02.034
Abstract:
A series of studies on speaker recognition algorithm based on relevance vector machine (RVM) and gaussian mixture model (GMM) was proposed in this paper. The sparseness and probability prediction of RVM make the algorithm suitable for speaker recognition in applications. The robust speech features based on GMM are investigated. In contrast to the most current systems based on frame-level discrimination, the approach has two outstanding merits. The first is the system provides direct discrimination between whole sequences by combining GMM as underlying generative models in feature-space. The paper focused on two main feature space: mel-frequency cepstrum coefficient (MFCC) and instantaneous frequencies (IF). The second combines the high generalization, kernel tricks, and sparser performance of RVM to generate more robust classification results and to reduce the computational complexity. The simulations using the Chains database and the AHUMADA database show that the proposed algorithm outperforms the other systems on reducing the relative error rates and reducing the computational complexity in high dimensionality space and big scale data.
A series of studies on speaker recognition algorithm based on relevance vector machine (RVM) and gaussian mixture model (GMM) was proposed in this paper. The sparseness and probability prediction of RVM make the algorithm suitable for speaker recognition in applications. The robust speech features based on GMM are investigated. In contrast to the most current systems based on frame-level discrimination, the approach has two outstanding merits. The first is the system provides direct discrimination between whole sequences by combining GMM as underlying generative models in feature-space. The paper focused on two main feature space: mel-frequency cepstrum coefficient (MFCC) and instantaneous frequencies (IF). The second combines the high generalization, kernel tricks, and sparser performance of RVM to generate more robust classification results and to reduce the computational complexity. The simulations using the Chains database and the AHUMADA database show that the proposed algorithm outperforms the other systems on reducing the relative error rates and reducing the computational complexity in high dimensionality space and big scale data.
2010, 39(2): 316-320.
doi: 10.3969/j.issn.1001-0548.2010.02.035
Abstract:
Intelligently optimal support vector machine (SVM) were introduced in electric utility boiler to improve short-term load forecasting accuracy and generalization ability. Wavelet transform is adopted to filter noise in training and testing data set. Kernel principle component analysis is used in feature selection. Then quantum-behaved particle swarm algorithm is chosen to determinate optimal hyper-parameter in SVM. This optimal algorithm has been tested on power plant and the results show that the prediction can get higher precision and convergence speed.
Intelligently optimal support vector machine (SVM) were introduced in electric utility boiler to improve short-term load forecasting accuracy and generalization ability. Wavelet transform is adopted to filter noise in training and testing data set. Kernel principle component analysis is used in feature selection. Then quantum-behaved particle swarm algorithm is chosen to determinate optimal hyper-parameter in SVM. This optimal algorithm has been tested on power plant and the results show that the prediction can get higher precision and convergence speed.
