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2001 Vol. 23, No. 9
Display Method:
2001, 23(9): 833-840.
Abstract:
Watermarking, as a new technique mainly used for IPR protection and authentication, has become a research hotspot not long after its appearance. Many effective watermarking algorithms have been proposed. But the mature of watermark technology is not enough for IPR, protection. Confronted with current various attack method, a secure watermarking architecture must be built to standardize the whole process,, from watermark insertion to detection. The AQUARELLE system is a good example for showing how IMPRIMATU--an architecture for IPR, protection is operated. The secure flaws of IMPRIMATUR and AQUARELLE system wa- terinarking protocol will also be pointed out. Further, a new secure watermarking architecture will be proposed. Its effectiveness will make up for the flaws mentioned above.
Watermarking, as a new technique mainly used for IPR protection and authentication, has become a research hotspot not long after its appearance. Many effective watermarking algorithms have been proposed. But the mature of watermark technology is not enough for IPR, protection. Confronted with current various attack method, a secure watermarking architecture must be built to standardize the whole process,, from watermark insertion to detection. The AQUARELLE system is a good example for showing how IMPRIMATU--an architecture for IPR, protection is operated. The secure flaws of IMPRIMATUR and AQUARELLE system wa- terinarking protocol will also be pointed out. Further, a new secure watermarking architecture will be proposed. Its effectiveness will make up for the flaws mentioned above.
2001, 23(9): 841-846.
Abstract:
An identification scheme based on parity check matrix of error-correcting codes over GF(2) was proposed in the paper A New Paradigm for Public Key Identification by J. Stern(1996), a new identification scheme based on parity check matrix of rank distance codes over GF(qN) (q is a prime) is proposed in this paper, the limitation on the weight of mysterious datum s is changed into the limitation on the rank of s. It is proved that the given protocol is a zero-knowledge interactive proof in the random oracle model, and it is shown that the scheme is more secure than the scheme of J. Stern when parameters are selected properly.
An identification scheme based on parity check matrix of error-correcting codes over GF(2) was proposed in the paper A New Paradigm for Public Key Identification by J. Stern(1996), a new identification scheme based on parity check matrix of rank distance codes over GF(qN) (q is a prime) is proposed in this paper, the limitation on the weight of mysterious datum s is changed into the limitation on the rank of s. It is proved that the given protocol is a zero-knowledge interactive proof in the random oracle model, and it is shown that the scheme is more secure than the scheme of J. Stern when parameters are selected properly.
2001, 23(9): 847-853.
Abstract:
Multiuser Detection (MUD) is a key technique in DS/CDMA systems. Antenna array has also promoted the investigation of Multiple Input Multiple Output(MIMO) system. In this paper a MUD method combined with MIMO considerations is proposed for multiuser interference reduction in antenna array DS/CDMA system. The knowledge that the base station knows many users spreading codes is utilized to form a semiblind MUD algorithm. This algorithm can work under slow fading environment, and simulation proves the superiority of the semiblind algorithm over the conventional blind algorithm.
Multiuser Detection (MUD) is a key technique in DS/CDMA systems. Antenna array has also promoted the investigation of Multiple Input Multiple Output(MIMO) system. In this paper a MUD method combined with MIMO considerations is proposed for multiuser interference reduction in antenna array DS/CDMA system. The knowledge that the base station knows many users spreading codes is utilized to form a semiblind MUD algorithm. This algorithm can work under slow fading environment, and simulation proves the superiority of the semiblind algorithm over the conventional blind algorithm.
2001, 23(9): 854-860.
Abstract:
This paper describes two kinds of AAL2 packet voice multiplexers based on input and output bit dropping. An algorithm for determining the bit dropping thresholds using the number of voice packets to determine the thresholds is presented with relevant computation formula. The computer simulation results show that the algorithm presented here is good for determining the bit dropping thresholds with low packet delay and small packet loss probability and easy operation.
This paper describes two kinds of AAL2 packet voice multiplexers based on input and output bit dropping. An algorithm for determining the bit dropping thresholds using the number of voice packets to determine the thresholds is presented with relevant computation formula. The computer simulation results show that the algorithm presented here is good for determining the bit dropping thresholds with low packet delay and small packet loss probability and easy operation.
2001, 23(9): 861-867.
Abstract:
Total variation based image restoration and reconstruction lead to a kind of minimization problem that turns out to be a nonlinear integro-differential equation of elliptic type. An effective linearization and. discretization method is essential for solving the problem. The fixed point iteration proposed by C. R. Vogel and M. E. Oman(1996) is an elegant scheme of linearization. For discretization of the problem, however, the reported methods mostly involve the skills in numerical solutions of differential equations that are not amiable for the image processing community. In this paper, a discretization method is presented that needs only con- ventional technique for image processing. The method can simplify the implementation of the fixed point iteration scheme. The experimental results of image restoration and image denoising are used to justify the method.
Total variation based image restoration and reconstruction lead to a kind of minimization problem that turns out to be a nonlinear integro-differential equation of elliptic type. An effective linearization and. discretization method is essential for solving the problem. The fixed point iteration proposed by C. R. Vogel and M. E. Oman(1996) is an elegant scheme of linearization. For discretization of the problem, however, the reported methods mostly involve the skills in numerical solutions of differential equations that are not amiable for the image processing community. In this paper, a discretization method is presented that needs only con- ventional technique for image processing. The method can simplify the implementation of the fixed point iteration scheme. The experimental results of image restoration and image denoising are used to justify the method.
2001, 23(9): 868-874.
Abstract:
This paper proposes a novel parallel algorithm for template matching of image division block based on a K-ary 2-cube network SIMD computer. For the template matching on an N by N image, M by M template and K by K processing unit array (M K, N = BK, B 1), the algorithm is able to realize template matching by dividing an image into blocks. Compared with known algorithms, the algorithm is able to process an image whose size is larger than that of the processing unit.
This paper proposes a novel parallel algorithm for template matching of image division block based on a K-ary 2-cube network SIMD computer. For the template matching on an N by N image, M by M template and K by K processing unit array (M K, N = BK, B 1), the algorithm is able to realize template matching by dividing an image into blocks. Compared with known algorithms, the algorithm is able to process an image whose size is larger than that of the processing unit.
2001, 23(9): 875-878.
Abstract:
In this paper, a hybrid aJgorithm based on the combination of genetic algorithm and gradient method is proposed. It can help the gradient method to skip the local optimum and achieve the global minimum. The convergence of the hybrid algorithm is proved and the simulation result shows the effective of the algorithm at the end.
In this paper, a hybrid aJgorithm based on the combination of genetic algorithm and gradient method is proposed. It can help the gradient method to skip the local optimum and achieve the global minimum. The convergence of the hybrid algorithm is proved and the simulation result shows the effective of the algorithm at the end.
2001, 23(9): 879-889.
Abstract:
This paper studies the attraction characteristics of a kind of symmetric discrete Hopfield neural networks, the network with ri-cube as its structure and connection situation, called n-cube network. The structure of the attraction states/cycles and their attraction diameters are explored. The result is that the attraction region is of same size and so is the attraction diameters for the attraction states/cycles with same attraction structure. Furthermore, the above result is extended to a more general asymmetric discrete Hopfield network and the conditions for the network to be (or partially to be) with the same attraction states/cycles as those of n-cube network are studied, and its attraction diameters are presented.
This paper studies the attraction characteristics of a kind of symmetric discrete Hopfield neural networks, the network with ri-cube as its structure and connection situation, called n-cube network. The structure of the attraction states/cycles and their attraction diameters are explored. The result is that the attraction region is of same size and so is the attraction diameters for the attraction states/cycles with same attraction structure. Furthermore, the above result is extended to a more general asymmetric discrete Hopfield network and the conditions for the network to be (or partially to be) with the same attraction states/cycles as those of n-cube network are studied, and its attraction diameters are presented.
2001, 23(9): 890-898.
Abstract:
In this paper, a 3-D imaging technique for interferometric inverse synthetic aperture radar is presented. And the criteria of determing and the angle glint in interferometric angle measurement are given. Furthermore, the 3-D imaging technique under two tracking systems is analyzed. This technique can effectively overcome the random phase dithering caused by tracking error under the continuous tracking system and satisfactorily solve the alignment of the different focuses of ISAR images under the step tracking system.
In this paper, a 3-D imaging technique for interferometric inverse synthetic aperture radar is presented. And the criteria of determing and the angle glint in interferometric angle measurement are given. Furthermore, the 3-D imaging technique under two tracking systems is analyzed. This technique can effectively overcome the random phase dithering caused by tracking error under the continuous tracking system and satisfactorily solve the alignment of the different focuses of ISAR images under the step tracking system.
2001, 23(9): 899-904.
Abstract:
This paper presents auther s primary results in the simulation study on polari-metric SAR. First, the mathematical model of the raw returns of multi-point targets received by the polarimetric SAR is established. Then four complex images of different transmit- and receive-polarizations are produced after imaging process. After that, the scattering matrix of every point target is computed based on the four complex images. Afterwards, four circular polarization images are produced using polarization synthesis. Finally, some analyses of the simulation results are presented. The results show the effectiveness of this simulation approach.
This paper presents auther s primary results in the simulation study on polari-metric SAR. First, the mathematical model of the raw returns of multi-point targets received by the polarimetric SAR is established. Then four complex images of different transmit- and receive-polarizations are produced after imaging process. After that, the scattering matrix of every point target is computed based on the four complex images. Afterwards, four circular polarization images are produced using polarization synthesis. Finally, some analyses of the simulation results are presented. The results show the effectiveness of this simulation approach.
2001, 23(9): 905-911.
Abstract:
In ranging radar, range ambiguity usually exists. Computing amount of overall search algorithm to solve the problem is analyzed, and it is pointed out that this algorithm is unsuitable for ranging in real time. Then two fast algorithms that can attain the true solution of original equation set under certain evaluation function are put forward. These algorithms effectiveness is proved by theory analyses and computer simulation.
In ranging radar, range ambiguity usually exists. Computing amount of overall search algorithm to solve the problem is analyzed, and it is pointed out that this algorithm is unsuitable for ranging in real time. Then two fast algorithms that can attain the true solution of original equation set under certain evaluation function are put forward. These algorithms effectiveness is proved by theory analyses and computer simulation.
2001, 23(9): 912-918.
Abstract:
The method of monopulse radar 3-D imaging in stepped tracking mode is presented. Then the amplitude linear modulation of error signals in stepped tracking mode is analyzed with its compensation method followed and so the problem of precisely tracking of target is solved. Finally the validity of these methods is proven by the simulation results.
The method of monopulse radar 3-D imaging in stepped tracking mode is presented. Then the amplitude linear modulation of error signals in stepped tracking mode is analyzed with its compensation method followed and so the problem of precisely tracking of target is solved. Finally the validity of these methods is proven by the simulation results.
2001, 23(9): 919-923.
Abstract:
In this paper, based on LPC adaptive forward-backward quantization, a novel variable-rate MELP speech coder is proposed, in which linear prediction is done by using either the current (forward LPC) or previously decoded (backward LPC) speech frames. The backward LPC scheme shall be applied, i.e., the LPC coefficients based on the previously decoded optimal speech frame are used to encode the current frame and only the time sequence code shall be transmitted to the decoder, so, average LPC bit number becomes smaller. Computer simulation shows significant average overall bit rate reduction is achieved without compromising the decoded speech quality.
In this paper, based on LPC adaptive forward-backward quantization, a novel variable-rate MELP speech coder is proposed, in which linear prediction is done by using either the current (forward LPC) or previously decoded (backward LPC) speech frames. The backward LPC scheme shall be applied, i.e., the LPC coefficients based on the previously decoded optimal speech frame are used to encode the current frame and only the time sequence code shall be transmitted to the decoder, so, average LPC bit number becomes smaller. Computer simulation shows significant average overall bit rate reduction is achieved without compromising the decoded speech quality.
2001, 23(9): 924-928.
Abstract:
In this paper, based on conventional redundancy optimization and the genetic algorithm, a method of fuzzy redundancy optimization is studied, by which fuzzy objectives and fuzzy constraints are linear and nonlinear membership functions respectively. Finally, an example is given.
In this paper, based on conventional redundancy optimization and the genetic algorithm, a method of fuzzy redundancy optimization is studied, by which fuzzy objectives and fuzzy constraints are linear and nonlinear membership functions respectively. Finally, an example is given.
2001, 23(9): 929-932.
Abstract:
The mechanics of Field Electron Emission (FEE) from planar thin films of wide band-gap have been studied systematically. The basic model is the electron tunneling through the potential barriers at the interfaces, on the other hand the effect of scattering of the crystal lattice and the effect of micro conductive channel on FEE have been taken into consideration. The study result shows that the planar film structure is conformable for FEE cathode, because it has low voltage threshold and small range of energy distribution of the emitted electrons. Since the structure can be easily prepared, and its components are widely selectable, and its surface stability in mechanics and chemistry is outstanding, this structure is an ideal electron emitter.
The mechanics of Field Electron Emission (FEE) from planar thin films of wide band-gap have been studied systematically. The basic model is the electron tunneling through the potential barriers at the interfaces, on the other hand the effect of scattering of the crystal lattice and the effect of micro conductive channel on FEE have been taken into consideration. The study result shows that the planar film structure is conformable for FEE cathode, because it has low voltage threshold and small range of energy distribution of the emitted electrons. Since the structure can be easily prepared, and its components are widely selectable, and its surface stability in mechanics and chemistry is outstanding, this structure is an ideal electron emitter.
2001, 23(9): 933-936.
Abstract:
This paper presents the design of pre-filter which can meet the requirements of airborne operational L-SAR system. Pre-filtering processing is carried out with the newest high-speed ADSP21062 chip from AD company. Pre-filtering ratio is changable according to difi erent demands and the precision of calculation is improved in this design. In this paper, the principle and realization of pre-filter is introduced in detail.
This paper presents the design of pre-filter which can meet the requirements of airborne operational L-SAR system. Pre-filtering processing is carried out with the newest high-speed ADSP21062 chip from AD company. Pre-filtering ratio is changable according to difi erent demands and the precision of calculation is improved in this design. In this paper, the principle and realization of pre-filter is introduced in detail.
