Along with the development of modern molecular biology technologies, complete chloroplast genomes have been sequenced in various plant species to date, and the structure, function and expression of these genes have be...Along with the development of modern molecular biology technologies, complete chloroplast genomes have been sequenced in various plant species to date, and the structure, function and expression of these genes have been deter-mined. The chloroplast genome structure in most higher plants is stable, since the gene number, arrangement and composition are conservative. The determination of sugarcane chloroplast genome sequence laid a good foundation for sugarcane chloroplast related research. This article gives a review on the research progress of sugarcane chloroplast genome through the chloroplast genome map, gene structure, function, chloroplast RNA editing, and phylogenetic analysis in Saccharum and relat-ed genera. This study held great potential to clarify more directions in researches, including sugarcane chloroplast genetic transformation, complete chloroplast nu-cleotide sequence determination in Saccharum and closely related genera, cpSSRs development and application.展开更多
The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is foun...The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is found to contain prokaryote-like promoter structures: compared with prokaryotic promoters, the“-35”box (TTGACA) shows 100% homology while, in the ‘-10’box (TATACT), one different nucleotide is found. In addition, between these two boxes, there is a consensus sequence“TATATA”.just as in prokaryotic promoters. All these results indicate that millet psbA promoter has both prokaryotic and eukaryotic characteristies. The mRNA leader region of millet pshA gene is 87 bp, the same length as sorghum. However, an additional CTATTT sequence is found as compared with rice and an additional TTTT, as with wheat, barley and rye. So the differences between C3 and C4 plants may be universal in the family of Gramineae. Furthermore, computer analysis shows that a small stem-loop structure might be formed in pshA mRNA leader region in these six plants. The above-mentioned additional CTATTT sequence happens to be just located within the stem-loop structure, thus leading to different sizes of the stem-loops among these six species. It is likely that this small secondary structure may have some effect on the expression and regulation of the psbA gene.展开更多
When the time variable in quantum signal processing is discrete, the Fourier transform exists on the vector space of n-tuples over the Galois field F2, which plays an important role in the investigation of quantum sig...When the time variable in quantum signal processing is discrete, the Fourier transform exists on the vector space of n-tuples over the Galois field F2, which plays an important role in the investigation of quantum signals. By using Fourier transforms, the idea of quantum coding theory can be described in a setting that is much different from that seen that far. Quantum BCH codes can be defined as codes whose quantum states have certain specified consecutive spectral components equal to zero and the error-correcting ability is also described by the number of the consecutive zeros. Moreover, the decoding of quantum codes can be described spectrally with more efficiency.展开更多
The performance of OFDM systems may be degraded when intersymbol interference （ISI） channels have spectral nulls. Recently, the precoded OFDM was proposed to combat this problem. However, due to inserting （M- K） z...The performance of OFDM systems may be degraded when intersymbol interference （ISI） channels have spectral nulls. Recently, the precoded OFDM was proposed to combat this problem. However, due to inserting （M- K） zeros between each two sets of K consecutive information symbols, the average transmitting power of the precoded OFDM system reduces by 10log10（M/K） dB compared with the conventional OFDM system. Under the same points inverse fast Fourier transformation （IFFF）, the precoded OFDM system has a higher peak-to-average power ratio （PAPR） compared with the conventional OFDM system. This paper proposes a novel precoded BPSK-OFDM system based on Haar wavelet transformation. The Haar wavelet transformation operating decomposition over the vector information symbols produced by a precoder shows that half of the information symbols are zeros and the rest are either √2- or √2. Then, we have the peak power and PAPR reduced by 10log1002=3dB at most compared with the precoded OFDM system. Finally, we compare PAPR of the proposed OFDM system with the precoded OFDM and the conventional OFDM system.展开更多
To solve the problem of advanced digital manufacturing technology in the practical application, a knowledge engineering technology was introduced into the computer numerical control(CNC) programming. The knowledge acq...To solve the problem of advanced digital manufacturing technology in the practical application, a knowledge engineering technology was introduced into the computer numerical control(CNC) programming. The knowledge acquisition, knowledge representation and reasoning used in CNC programming were researched. The CNC programming system functional architecture of impeller parts based on knowledge based engineering(KBE) was constructed. The structural model of the general knowledge-based system(KBS) was also constructed. The KBS of CNC programming system was established through synthesizing database technology and knowledge base theory. And in the context of corporate needs, based on the knowledge-driven manufacturing platform(i.e. UG CAD/CAM), VC++6.0 and UG/Open, the KBS and UG CAD/CAM were integrated seamlessly and the intelligent CNC programming KBE system for the impeller parts was developed by integrating KBE and UG CAD/CAM system. A method to establish standard process templates was proposed, so as to develop the intelligent CNC programming system in which CNC machining process and process parameters were standardized by using this KBE system. For the impeller parts processing, the method applied in the development of the prototype system is proven to be viable, feasible and practical.展开更多
In this paper, an improved low-complexity sum-product decoding algorithm is presented for low-density parity-check （LDPC） codes. In the proposed algorithm, reduction in computational complexity is achieved by utiliz...In this paper, an improved low-complexity sum-product decoding algorithm is presented for low-density parity-check （LDPC） codes. In the proposed algorithm, reduction in computational complexity is achieved by utilizing fast Fourier transform （FFT） with time shift in the check node process. The improvement in the decoding performance is achieved by utilizing an op- timized integer constant in the variable node process. Simulation results show that the proposed algorithm achieves an overall coding gain improvement ranging from 0.04 to 0.46 dB. Moreover, when compared with the sum-product algorithm （SPA）, the proposed decoding algorithm can achieve a reduction of 42%-67% of the total number of arithmetic operations required for the decoding process.展开更多
基金Supported by National Natural Science Foundation of China(31360357)Natural Science Foundation of Guangxi Zhuang Autonomous Region(2013GXNSFAA019051)Earmarked Fund for China Agriculture Research System(CARS-20-1-3)~~
文摘Along with the development of modern molecular biology technologies, complete chloroplast genomes have been sequenced in various plant species to date, and the structure, function and expression of these genes have been deter-mined. The chloroplast genome structure in most higher plants is stable, since the gene number, arrangement and composition are conservative. The determination of sugarcane chloroplast genome sequence laid a good foundation for sugarcane chloroplast related research. This article gives a review on the research progress of sugarcane chloroplast genome through the chloroplast genome map, gene structure, function, chloroplast RNA editing, and phylogenetic analysis in Saccharum and relat-ed genera. This study held great potential to clarify more directions in researches, including sugarcane chloroplast genetic transformation, complete chloroplast nu-cleotide sequence determination in Saccharum and closely related genera, cpSSRs development and application.
文摘The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is found to contain prokaryote-like promoter structures: compared with prokaryotic promoters, the“-35”box (TTGACA) shows 100% homology while, in the ‘-10’box (TATACT), one different nucleotide is found. In addition, between these two boxes, there is a consensus sequence“TATATA”.just as in prokaryotic promoters. All these results indicate that millet psbA promoter has both prokaryotic and eukaryotic characteristies. The mRNA leader region of millet pshA gene is 87 bp, the same length as sorghum. However, an additional CTATTT sequence is found as compared with rice and an additional TTTT, as with wheat, barley and rye. So the differences between C3 and C4 plants may be universal in the family of Gramineae. Furthermore, computer analysis shows that a small stem-loop structure might be formed in pshA mRNA leader region in these six plants. The above-mentioned additional CTATTT sequence happens to be just located within the stem-loop structure, thus leading to different sizes of the stem-loops among these six species. It is likely that this small secondary structure may have some effect on the expression and regulation of the psbA gene.
基金The project supported by National Natural Science Foundation of China under Grant No. 60472018, and the Foundation of National Laboratory for Modern Communications
文摘When the time variable in quantum signal processing is discrete, the Fourier transform exists on the vector space of n-tuples over the Galois field F2, which plays an important role in the investigation of quantum signals. By using Fourier transforms, the idea of quantum coding theory can be described in a setting that is much different from that seen that far. Quantum BCH codes can be defined as codes whose quantum states have certain specified consecutive spectral components equal to zero and the error-correcting ability is also described by the number of the consecutive zeros. Moreover, the decoding of quantum codes can be described spectrally with more efficiency.
文摘The performance of OFDM systems may be degraded when intersymbol interference （ISI） channels have spectral nulls. Recently, the precoded OFDM was proposed to combat this problem. However, due to inserting （M- K） zeros between each two sets of K consecutive information symbols, the average transmitting power of the precoded OFDM system reduces by 10log10（M/K） dB compared with the conventional OFDM system. Under the same points inverse fast Fourier transformation （IFFF）, the precoded OFDM system has a higher peak-to-average power ratio （PAPR） compared with the conventional OFDM system. This paper proposes a novel precoded BPSK-OFDM system based on Haar wavelet transformation. The Haar wavelet transformation operating decomposition over the vector information symbols produced by a precoder shows that half of the information symbols are zeros and the rest are either √2- or √2. Then, we have the peak power and PAPR reduced by 10log1002=3dB at most compared with the precoded OFDM system. Finally, we compare PAPR of the proposed OFDM system with the precoded OFDM and the conventional OFDM system.
基金Project(12ZT14)supported by the Natural Science Foundation of Shanghai Municipal Education Commission,China
文摘To solve the problem of advanced digital manufacturing technology in the practical application, a knowledge engineering technology was introduced into the computer numerical control(CNC) programming. The knowledge acquisition, knowledge representation and reasoning used in CNC programming were researched. The CNC programming system functional architecture of impeller parts based on knowledge based engineering(KBE) was constructed. The structural model of the general knowledge-based system(KBS) was also constructed. The KBS of CNC programming system was established through synthesizing database technology and knowledge base theory. And in the context of corporate needs, based on the knowledge-driven manufacturing platform(i.e. UG CAD/CAM), VC++6.0 and UG/Open, the KBS and UG CAD/CAM were integrated seamlessly and the intelligent CNC programming KBE system for the impeller parts was developed by integrating KBE and UG CAD/CAM system. A method to establish standard process templates was proposed, so as to develop the intelligent CNC programming system in which CNC machining process and process parameters were standardized by using this KBE system. For the impeller parts processing, the method applied in the development of the prototype system is proven to be viable, feasible and practical.
文摘In this paper, an improved low-complexity sum-product decoding algorithm is presented for low-density parity-check （LDPC） codes. In the proposed algorithm, reduction in computational complexity is achieved by utilizing fast Fourier transform （FFT） with time shift in the check node process. The improvement in the decoding performance is achieved by utilizing an op- timized integer constant in the variable node process. Simulation results show that the proposed algorithm achieves an overall coding gain improvement ranging from 0.04 to 0.46 dB. Moreover, when compared with the sum-product algorithm （SPA）, the proposed decoding algorithm can achieve a reduction of 42%-67% of the total number of arithmetic operations required for the decoding process.
