Information loss recovery techniques are important for transmitting images over error-prone channels at the decoder. A novel error recovery scheme for JPEG2000 image is presented in this paper, which adopts different ...Information loss recovery techniques are important for transmitting images over error-prone channels at the decoder. A novel error recovery scheme for JPEG2000 image is presented in this paper, which adopts different techniques for the lowest frequency coefficients and high frequency coefficients in the wavelet domain. The low-frequency recovery algorithm was implemented by adopting the watermarking technique and the packet structure of JPEG2000. The low-frequency eoefficients taken as the hidden data were extracted from the compressed bit stream, and then were embedded back into the bit stream itself prior to transmission. The embedded data were used to recover the information loss. High-frequency reconstruction was performed in bitplane base. The damaged bitplanes were recovered according to the correlation in the wavelet subband structure and by using the algorithm based on the horizontal and vertical edge detection. Experiments verified the effectiveness of these algorithms.展开更多
The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the ...The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction (MRCI) approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.展开更多
For communication systems with heavy burst noise, an optimal Forward Error Correction(FEC) scheme is expected to have a large burst error correction capability while simultaneously owning moderate random error correct...For communication systems with heavy burst noise, an optimal Forward Error Correction(FEC) scheme is expected to have a large burst error correction capability while simultaneously owning moderate random error correction capability. This letter presents a new FEC scheme based on multiple-symbol interleaved Reed-Solomon codes and an associated two-pass decoding algorithm. It is shown that the proposed multi-symbol interleaved Reed-Solomon scheme can achieve nearly twice as much as the burst error correction capability of conventional single-symbol interleaved Reed-Solomon codes with the same code length and code rate.展开更多
Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemen...Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.展开更多
Due to the ubiquitous open air links and complex electromagnetic environment in the satellite communications,how to ensure the security and reliability of the information through the satellite communications is an urg...Due to the ubiquitous open air links and complex electromagnetic environment in the satellite communications,how to ensure the security and reliability of the information through the satellite communications is an urgent problem.This paper combines the AES(Advanced Encryption Standard) with LDPC(Low Density Parity Check Code) to design a secure and reliable error correction method — SEEC(Satellite Encryption and Error Correction).This method selects the LDPC codes,which is suitable for satellite communications,and uses the AES round key to control the encoding process,at the same time,proposes a new algorithm of round key generation.Based on a fairly good property in error correction in satellite communications,the method improves the security of the system,achieves a shorter key size,and then makes the key management easier.Eventually,the method shows a great error correction capability and encryption effect by the MATLAB simulation.展开更多
A 5-level PFC (power factor correction) topology with fault-diagnostic and fault-tolerant capability is proposed and compared to known structures. It is derived from a 3-level non differential double-boost PFC inclu...A 5-level PFC (power factor correction) topology with fault-diagnostic and fault-tolerant capability is proposed and compared to known structures. It is derived from a 3-level non differential double-boost PFC including fly-cap cells. The series-connection of the two low-voltage switching-cells is decoupled by a single flying capacitor that provides a direct fault-tolerant capability and a post-failure operation increasing the availability of converter. The monitoring of the voltages across flying capacitors allows a rapid detection and localization either for open circuit failure or short-circuits failure. A PWM (pulse width modulation) phase-disposition type reconfiguration is also used and presented in order to optimize both normal operation and post-fault continuation. The design and the most important features are highlighted thanks to a digital control frame and a mock-up rated to: AC voltage network 115 V-load 400 V-nominal power 4 kW-switching frequency 62 kHz.展开更多
Computer Assisted Language Learning (CALL) has been in use as a learner centered method since 1960. In this paper an attempt is made to evolve a Remedial Grammar (RG) which enables the teacher to develop a reperto...Computer Assisted Language Learning (CALL) has been in use as a learner centered method since 1960. In this paper an attempt is made to evolve a Remedial Grammar (RG) which enables the teacher to develop a repertoire of remedial activities based on the errors identified following Error Analysis (EA) for repeated presentation. The error types are considered as teaching/learning points. The present paper argues that CALL is the right model for effective remedial learning. Remedial Gmaster (RGm), an authoring package is introduced. This is an exclusive mode of error correction in which interlingual, intralingual, developmental, and global errors are dealt with. The syntactical problems due to the subtle difference between simple past and perfect tenses in English language use are discussed and CALL authoring package presented.展开更多
As residual attitude errors are likely to affect the synthetic aperture radar (SAR) imaging, this paper presents a SAR motioncompensation algorithm based on the correction of residual attitude errors. The existing met...As residual attitude errors are likely to affect the synthetic aperture radar (SAR) imaging, this paper presents a SAR motioncompensation algorithm based on the correction of residual attitude errors. The existing methods all use the antenna stableplatform to correct the attitude errors, and then compensate the trajectory deviations in the following imaging process. Besidescompensating the trajectory deviations, the modified method of this paper also considers the influence of residual attitude er-rors on the SAR imaging, and can compensate both the trajectory deviations and the residual attitude errors. Compared withthe existing methods, the modified method in this paper can more precisely compensate the imperfect motion on the SAR im-aging, especially good for the SAR system with a small platform, near operating distance and a narrow antenna beam. Such asystem causes severe residual attitude errors and needs to consider the influence of antenna beam pointing errors on the imag-ing. The validity of the modified method presented by this paper is demonstrated by the result of the experiment.展开更多
For applying the perfect code to transmit quantum information over a noise channel,the standard protocol contains four steps:the encoding,the noise channel,the error-correction operation,and the decoding.In present wo...For applying the perfect code to transmit quantum information over a noise channel,the standard protocol contains four steps:the encoding,the noise channel,the error-correction operation,and the decoding.In present work,we show that this protocol can be simplified.The error-correction operation is not necessary if the decoding is realized by the so-called complete unitary transformation.We also offer a quantum circuit,which can correct the arbitrary single-qubit errors.展开更多
Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density pari...Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density parity-check(LDPC) codes. The qua-sicyclic construction method can extend short block length codes and further eliminate the shortest cycle. In this paper, by combining the PEG algorithm and quasi-cyclic construction method, we design long block length irregular LDPC codes with high error-correcting capacity. Based on these LDPC codes, we achieve high-efficiency Gaussian key reconciliation with slice recon-ciliation based on multilevel coding/multistage decoding with an efficiency of 93.7%.展开更多
文摘Information loss recovery techniques are important for transmitting images over error-prone channels at the decoder. A novel error recovery scheme for JPEG2000 image is presented in this paper, which adopts different techniques for the lowest frequency coefficients and high frequency coefficients in the wavelet domain. The low-frequency recovery algorithm was implemented by adopting the watermarking technique and the packet structure of JPEG2000. The low-frequency eoefficients taken as the hidden data were extracted from the compressed bit stream, and then were embedded back into the bit stream itself prior to transmission. The embedded data were used to recover the information loss. High-frequency reconstruction was performed in bitplane base. The damaged bitplanes were recovered according to the correlation in the wavelet subband structure and by using the algorithm based on the horizontal and vertical edge detection. Experiments verified the effectiveness of these algorithms.
文摘The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction (MRCI) approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.
文摘For communication systems with heavy burst noise, an optimal Forward Error Correction(FEC) scheme is expected to have a large burst error correction capability while simultaneously owning moderate random error correction capability. This letter presents a new FEC scheme based on multiple-symbol interleaved Reed-Solomon codes and an associated two-pass decoding algorithm. It is shown that the proposed multi-symbol interleaved Reed-Solomon scheme can achieve nearly twice as much as the burst error correction capability of conventional single-symbol interleaved Reed-Solomon codes with the same code length and code rate.
基金Supported by the National 973 Programs (2013CB329104)the National Natural Science Foundations of China (No. 61071090, No. 61171093)+3 种基金the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province (CXZZ11_0388)Jiangsu Province Natural Science Foundation Key Projects (11KJA510001)National Science and Technology Key Projects (2011ZX03005-004-003)Jiangsu 973 Projects (BK2011027)
文摘Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.
基金supported by the National 863 Project of China under Grant No.2012AA01A509,No.2012AA120800
文摘Due to the ubiquitous open air links and complex electromagnetic environment in the satellite communications,how to ensure the security and reliability of the information through the satellite communications is an urgent problem.This paper combines the AES(Advanced Encryption Standard) with LDPC(Low Density Parity Check Code) to design a secure and reliable error correction method — SEEC(Satellite Encryption and Error Correction).This method selects the LDPC codes,which is suitable for satellite communications,and uses the AES round key to control the encoding process,at the same time,proposes a new algorithm of round key generation.Based on a fairly good property in error correction in satellite communications,the method improves the security of the system,achieves a shorter key size,and then makes the key management easier.Eventually,the method shows a great error correction capability and encryption effect by the MATLAB simulation.
文摘A 5-level PFC (power factor correction) topology with fault-diagnostic and fault-tolerant capability is proposed and compared to known structures. It is derived from a 3-level non differential double-boost PFC including fly-cap cells. The series-connection of the two low-voltage switching-cells is decoupled by a single flying capacitor that provides a direct fault-tolerant capability and a post-failure operation increasing the availability of converter. The monitoring of the voltages across flying capacitors allows a rapid detection and localization either for open circuit failure or short-circuits failure. A PWM (pulse width modulation) phase-disposition type reconfiguration is also used and presented in order to optimize both normal operation and post-fault continuation. The design and the most important features are highlighted thanks to a digital control frame and a mock-up rated to: AC voltage network 115 V-load 400 V-nominal power 4 kW-switching frequency 62 kHz.
文摘Computer Assisted Language Learning (CALL) has been in use as a learner centered method since 1960. In this paper an attempt is made to evolve a Remedial Grammar (RG) which enables the teacher to develop a repertoire of remedial activities based on the errors identified following Error Analysis (EA) for repeated presentation. The error types are considered as teaching/learning points. The present paper argues that CALL is the right model for effective remedial learning. Remedial Gmaster (RGm), an authoring package is introduced. This is an exclusive mode of error correction in which interlingual, intralingual, developmental, and global errors are dealt with. The syntactical problems due to the subtle difference between simple past and perfect tenses in English language use are discussed and CALL authoring package presented.
基金supported by the Knowledge Innovative Program of the Chinese Academy of Sciences (Grant No. 053Z170138)
文摘As residual attitude errors are likely to affect the synthetic aperture radar (SAR) imaging, this paper presents a SAR motioncompensation algorithm based on the correction of residual attitude errors. The existing methods all use the antenna stableplatform to correct the attitude errors, and then compensate the trajectory deviations in the following imaging process. Besidescompensating the trajectory deviations, the modified method of this paper also considers the influence of residual attitude er-rors on the SAR imaging, and can compensate both the trajectory deviations and the residual attitude errors. Compared withthe existing methods, the modified method in this paper can more precisely compensate the imperfect motion on the SAR im-aging, especially good for the SAR system with a small platform, near operating distance and a narrow antenna beam. Such asystem causes severe residual attitude errors and needs to consider the influence of antenna beam pointing errors on the imag-ing. The validity of the modified method presented by this paper is demonstrated by the result of the experiment.
文摘For applying the perfect code to transmit quantum information over a noise channel,the standard protocol contains four steps:the encoding,the noise channel,the error-correction operation,and the decoding.In present work,we show that this protocol can be simplified.The error-correction operation is not necessary if the decoding is realized by the so-called complete unitary transformation.We also offer a quantum circuit,which can correct the arbitrary single-qubit errors.
基金supported by the National Natural Science Foundation of China(Grant No.61378010)the Natural Science Foundation of Shanxi Province(Grant No.2014011007-1)
文摘Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density parity-check(LDPC) codes. The qua-sicyclic construction method can extend short block length codes and further eliminate the shortest cycle. In this paper, by combining the PEG algorithm and quasi-cyclic construction method, we design long block length irregular LDPC codes with high error-correcting capacity. Based on these LDPC codes, we achieve high-efficiency Gaussian key reconciliation with slice recon-ciliation based on multilevel coding/multistage decoding with an efficiency of 93.7%.