Recently a Hybrid Carrier (HC) scheme based on Weighted-type Fractional Fourier Transform (WFRFT) was proposed and developed, which contains Single Carrier (SC) and Multi-Carrier (MC) synergetie transmission. ...Recently a Hybrid Carrier (HC) scheme based on Weighted-type Fractional Fourier Transform (WFRFT) was proposed and developed, which contains Single Carrier (SC) and Multi-Carrier (MC) synergetie transmission. The wide interest is primarily due to its appealing characteristics, such as the robust performances in different types of selective fading channels and a great deal of potential for secure communications. According to the literatures, the HC signal and SC or MC signal probability distributions are different. In particular, some benefits of this HC scheme are brought by the quasi-Gaussian distribution of WFRFT signals. However, until now researchers have only presented statistic properties through computer simulations, and the accurate expressions of signals are not derived yet. In this paper, we derive the accu- rate and rigorously established closed-form expressions of Probability Density Function (PDF) of WFRFT signal real and imaginary parts with a large number of QPSK subcarriers, and this PDF can describe the behavior of data modulated by WFRFT, avoiding the complex computation for extensive computer simulations. Furthermore, the components of PDF expression are described and analyzed, and it is revealed that the tendency of signal quasi-Gaussian changes with the increasing of the parameter a (a in (0,1]). To validate the analytical results, extensive simulations have been conducted, showing a very good match between the analytical results and the real situations. The contribution of this paper may be useful to deduce the closed form expressions of Bit Error Ratio (BER), the Complementary Cumulative Distribution Function (CCDF) of Peak to Average Power Ratio (PAPR), and other analytical studies which adopt the PDF.展开更多
The spectrum allocation for cognitive radio networks(CRNs) has received considerable studies under the assumption that the bandwidth of spectrum holes is static. However, in practice, the bandwidth of spectrum holes i...The spectrum allocation for cognitive radio networks(CRNs) has received considerable studies under the assumption that the bandwidth of spectrum holes is static. However, in practice, the bandwidth of spectrum holes is time-varied due to primary user/secondary user(PU/SU) activity and mobility, which result in non-determinacy. This paper studies the spectrum allocation for CRNs with non-deterministic bandwidth of spectrum holes. We present a novel probability density function(PDF) through order statistics as well as its simplified form to describe the statistical properties of spectrum holes, with which a statistical spectrum allocation model based on stochastic multiple knapsack problem(MKP) is formulated for spectrum allocation with non-deterministic bandwidth of spectrum holes. To reduce the computational complexity, we transform this stochastic programming problem into a constant MKP through exploiting the properties of cumulative distribution function(CDF), which can be solved via MTHG algorithm by using auxiliary variables. Simulation results illustrate that the proposed statistical spectrum allocation algorithm can achieve better performance compared with the existing algorithms when the bandwidth of spectrum holes is time-varied.展开更多
An experiment was conducted to evaluate physiological maturity of French bean genotypes at District Seed Farm "D" Block, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal during winter season of both...An experiment was conducted to evaluate physiological maturity of French bean genotypes at District Seed Farm "D" Block, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal during winter season of both 2012-2013 and 2013-2014. All the five genotypes were grown with sufficient population in three replications following randomized block design (RBD) for the purpose of developmental studies. Developing pods were harvested at different stages, starting from 7 days after anthesis (7 DAA) to 49 DAA with an interval of 7 d, including the field maturity stage, thus leading to study on maximum seven different stages. Harvested pods and seeds were utilized for this development programme through dry seed weight, germination and vigour index. Enhancement in dry matter accumulation in seed continued till 42 DAA for Selection 9 and Victoria in both the years; it was 49 and 42 DAA for Sonali in respective years; it was 49 DAA for Abhay in both the years; and for Deepali, it was 42 DAA along with statistically similar magnitude at 49 DAA. Significant enhancement in germination potential of developing seeds continued till 42 DAA for Selection 9 and Deepali, while it was 49 DAA for the other three genotypes. Enhancement in vigour index continued till 49 DAA for all the genotypes except for Selection 9, for which it continued till 42 DAA and then declined.展开更多
For the stochastic structure with stochastic excitation, an advanced stratified line sampling (SLS) method is presented to obtain the cumulative distribution function (CDF) of the structural response and its sensitivi...For the stochastic structure with stochastic excitation, an advanced stratified line sampling (SLS) method is presented to obtain the cumulative distribution function (CDF) of the structural response and its sensitivity. The advanced stratified line sampling method introduces a set of middle failure subsets firstly. And for each subset, the conventional line sampling can be used to obtain the corresponding value of the response's CDF. At the same time, the sensitivity estimations of each failure subset can also be computed by modifying the important direction and corresponding reliability coefficients. The properties of CDF sensitivity are proved while the performance function is linear with normal random variables. After two simple examples are used to demonstrate the properties of CDF sensitivity and the feasibility of the presented method, the method employed to analyze the CDF and corresponding sensitivity of root bending moment (RBM) responses for the stochastic BAH is wing with gust excitation to a square-edged gust and to a Dryden gust. The results show that the parameters of the second and the fifth order modals exert more influence on the CDF of response than the other ones, and the presented SLS method can more significantly reduce the computational cost compared with Monte Carlo simulation (MCS).展开更多
基金supported by the National Natural Science Foundation General Program of China(No.61201146)the National Basic Research Program of China(2013CB329003)the Fundamental Research Funds for the Central Universities(HIT.NSRIF.2015022)
文摘Recently a Hybrid Carrier (HC) scheme based on Weighted-type Fractional Fourier Transform (WFRFT) was proposed and developed, which contains Single Carrier (SC) and Multi-Carrier (MC) synergetie transmission. The wide interest is primarily due to its appealing characteristics, such as the robust performances in different types of selective fading channels and a great deal of potential for secure communications. According to the literatures, the HC signal and SC or MC signal probability distributions are different. In particular, some benefits of this HC scheme are brought by the quasi-Gaussian distribution of WFRFT signals. However, until now researchers have only presented statistic properties through computer simulations, and the accurate expressions of signals are not derived yet. In this paper, we derive the accu- rate and rigorously established closed-form expressions of Probability Density Function (PDF) of WFRFT signal real and imaginary parts with a large number of QPSK subcarriers, and this PDF can describe the behavior of data modulated by WFRFT, avoiding the complex computation for extensive computer simulations. Furthermore, the components of PDF expression are described and analyzed, and it is revealed that the tendency of signal quasi-Gaussian changes with the increasing of the parameter a (a in (0,1]). To validate the analytical results, extensive simulations have been conducted, showing a very good match between the analytical results and the real situations. The contribution of this paper may be useful to deduce the closed form expressions of Bit Error Ratio (BER), the Complementary Cumulative Distribution Function (CCDF) of Peak to Average Power Ratio (PAPR), and other analytical studies which adopt the PDF.
基金supported by the National Natural Science Foundation of China (No.61501065, 91438104,No.61571069 and No.61601067)the Fundamental Research Funds for the Central Universities (No.106112015CDJXY160002,No.106112016CDJXY160001)the Chongqing Research Program of Basic Research and Frontier Technology (No.CSTC2016JCYJA0021)
文摘The spectrum allocation for cognitive radio networks(CRNs) has received considerable studies under the assumption that the bandwidth of spectrum holes is static. However, in practice, the bandwidth of spectrum holes is time-varied due to primary user/secondary user(PU/SU) activity and mobility, which result in non-determinacy. This paper studies the spectrum allocation for CRNs with non-deterministic bandwidth of spectrum holes. We present a novel probability density function(PDF) through order statistics as well as its simplified form to describe the statistical properties of spectrum holes, with which a statistical spectrum allocation model based on stochastic multiple knapsack problem(MKP) is formulated for spectrum allocation with non-deterministic bandwidth of spectrum holes. To reduce the computational complexity, we transform this stochastic programming problem into a constant MKP through exploiting the properties of cumulative distribution function(CDF), which can be solved via MTHG algorithm by using auxiliary variables. Simulation results illustrate that the proposed statistical spectrum allocation algorithm can achieve better performance compared with the existing algorithms when the bandwidth of spectrum holes is time-varied.
文摘An experiment was conducted to evaluate physiological maturity of French bean genotypes at District Seed Farm "D" Block, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal during winter season of both 2012-2013 and 2013-2014. All the five genotypes were grown with sufficient population in three replications following randomized block design (RBD) for the purpose of developmental studies. Developing pods were harvested at different stages, starting from 7 days after anthesis (7 DAA) to 49 DAA with an interval of 7 d, including the field maturity stage, thus leading to study on maximum seven different stages. Harvested pods and seeds were utilized for this development programme through dry seed weight, germination and vigour index. Enhancement in dry matter accumulation in seed continued till 42 DAA for Selection 9 and Victoria in both the years; it was 49 and 42 DAA for Sonali in respective years; it was 49 DAA for Abhay in both the years; and for Deepali, it was 42 DAA along with statistically similar magnitude at 49 DAA. Significant enhancement in germination potential of developing seeds continued till 42 DAA for Selection 9 and Deepali, while it was 49 DAA for the other three genotypes. Enhancement in vigour index continued till 49 DAA for all the genotypes except for Selection 9, for which it continued till 42 DAA and then declined.
基金the National Nature Science Foundation of China (Grant No. 51175425)the Aviation Science Foundation (Grant No. 2011ZA53015)+1 种基金the Aerospace Science and Technology Innovative Foundation (Grant No. 2011200093)the Nature Science Basic Research Fund of Shaanxi Province (Grant No. 2012JQ1015)
文摘For the stochastic structure with stochastic excitation, an advanced stratified line sampling (SLS) method is presented to obtain the cumulative distribution function (CDF) of the structural response and its sensitivity. The advanced stratified line sampling method introduces a set of middle failure subsets firstly. And for each subset, the conventional line sampling can be used to obtain the corresponding value of the response's CDF. At the same time, the sensitivity estimations of each failure subset can also be computed by modifying the important direction and corresponding reliability coefficients. The properties of CDF sensitivity are proved while the performance function is linear with normal random variables. After two simple examples are used to demonstrate the properties of CDF sensitivity and the feasibility of the presented method, the method employed to analyze the CDF and corresponding sensitivity of root bending moment (RBM) responses for the stochastic BAH is wing with gust excitation to a square-edged gust and to a Dryden gust. The results show that the parameters of the second and the fifth order modals exert more influence on the CDF of response than the other ones, and the presented SLS method can more significantly reduce the computational cost compared with Monte Carlo simulation (MCS).