本文讨论一类序号数列的遍历性,解决了文[1]提出的一个猜测(见下面定理).为叙述方便,在记法上与文[1]稍有不同.我们称R_n=(r_1,r_2,…,r_n)为生成数列,其中r_1为非负整数,r_2,…,r_n为正整数,令b_j=sum from i=1 to j(r_i),1≤j≤n得到...本文讨论一类序号数列的遍历性,解决了文[1]提出的一个猜测(见下面定理).为叙述方便,在记法上与文[1]稍有不同.我们称R_n=(r_1,r_2,…,r_n)为生成数列,其中r_1为非负整数,r_2,…,r_n为正整数,令b_j=sum from i=1 to j(r_i),1≤j≤n得到序号数列B_n=(b_1,b_2,…,b_n).当b_1,b_2,…,是模n的一个完全剩余系时,称B_n有遍历性.与文[1]相比,[1]中的R_(n-1)在这里增添了一项并改记为R_n,且这里的b_1不一定是1,这些改变并不是本质的.于是。展开更多
We determined the linear complexity of a family of p2-periodic binary threshold sequences and a family of p2-periodic binary sequences constructed using the Legendre symbol,both of which are derived from Fermat quotie...We determined the linear complexity of a family of p2-periodic binary threshold sequences and a family of p2-periodic binary sequences constructed using the Legendre symbol,both of which are derived from Fermat quotients modulo an odd prime p.If 2 is a primitive element modulo p2,the linear complexity equals to p2-p or p2-1,which is very close to the period and it is large enough for cryptographic purpose.展开更多
In present article a number of results are described in a systematic way concerning both signal and image processing problems with respect to atomic functions theory and Prouhet-Tbue-Morse sequence.
In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances i...In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.展开更多
A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal...A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal. Digital signal sequence is obtained through sampling signal measured over an integer number of signal periods, but digital reference sequence is acquired through mathematical operation, then digital phase sensitive detection can be implemented by calculating the cross-correlation function of digital signal sequence and digital reference sequence. In addition, the frequency response and phase character of the digital lock-in amplifier is analyzed. Finally, the designed digital lock-in amplifier is achieved. Expermental results show that the digital lock-in amplifier can be used for measuring weak signal with low ignal-to-noise ratio.展开更多
Digital data of precursors is noted for its high accuracy. Therefore, it is important to extract the high frequency information from the low ones in the digital data of precursors and to discriminate between the trend...Digital data of precursors is noted for its high accuracy. Therefore, it is important to extract the high frequency information from the low ones in the digital data of precursors and to discriminate between the trend anomalies and the short-term anomalies. This paper presents a method to separate the high frequency information from the low ones by using the wavelet transform to analyze the digital data of precursors, and illustrates with examples the train of thoughts of discriminating the short-term anomalies from trend anomalies by using the wavelet transform, thus provide a new effective approach for extracting the short-term and trend anomalies from the digital data of precursors.展开更多
Superlattices have great application potentials in thermo-electric materials and solid laser techniques.Their complicated heat transport mechanisms due to size effects,multi-interfaces and mini-band are very important...Superlattices have great application potentials in thermo-electric materials and solid laser techniques.Their complicated heat transport mechanisms due to size effects,multi-interfaces and mini-band are very important issues for the prediction of thermal conductivity.In this paper,the short-period Si/Ge superlattices are investigated by a modified series model based on the Debye-Callaway description.The Lambert Law is used to describe the phonon emission within hemisphere space.In addition,the phonon interface transmission coefficients obtained from the phonon wave packet simulation are incorporated into boundary condition of the model,which removes the fitting parameters in the model.Better agreement with experiment is obtained.The effects of temperature,wavelength-dependent phonon transmission,superlattice periods,as well as the thickness of Ge layer are considered in this paper.展开更多
文摘本文讨论一类序号数列的遍历性,解决了文[1]提出的一个猜测(见下面定理).为叙述方便,在记法上与文[1]稍有不同.我们称R_n=(r_1,r_2,…,r_n)为生成数列,其中r_1为非负整数,r_2,…,r_n为正整数,令b_j=sum from i=1 to j(r_i),1≤j≤n得到序号数列B_n=(b_1,b_2,…,b_n).当b_1,b_2,…,是模n的一个完全剩余系时,称B_n有遍历性.与文[1]相比,[1]中的R_(n-1)在这里增添了一项并改记为R_n,且这里的b_1不一定是1,这些改变并不是本质的.于是。
基金the National Natural Science Foundation of China，the Open Funds of State Key Laboratory of Information Security (Chinese Academy of Sciences)，the Program for New Century Excellent Talents in Fujian Province University
文摘We determined the linear complexity of a family of p2-periodic binary threshold sequences and a family of p2-periodic binary sequences constructed using the Legendre symbol,both of which are derived from Fermat quotients modulo an odd prime p.If 2 is a primitive element modulo p2,the linear complexity equals to p2-p or p2-1,which is very close to the period and it is large enough for cryptographic purpose.
基金Russian Foundation for Basic Research(No.130212065)
文摘In present article a number of results are described in a systematic way concerning both signal and image processing problems with respect to atomic functions theory and Prouhet-Tbue-Morse sequence.
基金the support of the National High Technology Research and Development Program of China (863) (Grant No. 2012AA1406)
文摘In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.
文摘A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal. Digital signal sequence is obtained through sampling signal measured over an integer number of signal periods, but digital reference sequence is acquired through mathematical operation, then digital phase sensitive detection can be implemented by calculating the cross-correlation function of digital signal sequence and digital reference sequence. In addition, the frequency response and phase character of the digital lock-in amplifier is analyzed. Finally, the designed digital lock-in amplifier is achieved. Expermental results show that the digital lock-in amplifier can be used for measuring weak signal with low ignal-to-noise ratio.
文摘Digital data of precursors is noted for its high accuracy. Therefore, it is important to extract the high frequency information from the low ones in the digital data of precursors and to discriminate between the trend anomalies and the short-term anomalies. This paper presents a method to separate the high frequency information from the low ones by using the wavelet transform to analyze the digital data of precursors, and illustrates with examples the train of thoughts of discriminating the short-term anomalies from trend anomalies by using the wavelet transform, thus provide a new effective approach for extracting the short-term and trend anomalies from the digital data of precursors.
基金supported by the National Basic Research Program of China(Grant No.2012CB933200)the National Natural Science Foundation of China(Grant No.51176091)Science Fund for Creative Research Groups of China(Grant No.51321002)
文摘Superlattices have great application potentials in thermo-electric materials and solid laser techniques.Their complicated heat transport mechanisms due to size effects,multi-interfaces and mini-band are very important issues for the prediction of thermal conductivity.In this paper,the short-period Si/Ge superlattices are investigated by a modified series model based on the Debye-Callaway description.The Lambert Law is used to describe the phonon emission within hemisphere space.In addition,the phonon interface transmission coefficients obtained from the phonon wave packet simulation are incorporated into boundary condition of the model,which removes the fitting parameters in the model.Better agreement with experiment is obtained.The effects of temperature,wavelength-dependent phonon transmission,superlattice periods,as well as the thickness of Ge layer are considered in this paper.
