Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among s...Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes.展开更多
The capture probability of interceptors has been deeply studied.Firstly,the definition of capture probability is analyzed.It is transformed into calculating the probability that the relative position vector between th...The capture probability of interceptors has been deeply studied.Firstly,the definition of capture probability is analyzed.It is transformed into calculating the probability that the relative position vector between the target and the interceptor locates in a certain cone.The relative position vector and associated covariance matrix are projected in line-of-sight coordinates,and the 3-dimensional integral of a probability function in a cone is calculated to obtain the capture probability.The integral equation is a complicated expression of probability,and it is simplified to an explicit approximate expression according to some assumptions based on the characteristics of the engineering problems.The approximation precision is analyzed by comparative simulation difference,which indicates that approximate assumptions are reasonable.Utilizing the explicit expression,the characteristics of capture probability are analyzed respectively with the factors,such as the distance between the interceptor and the target,the precision of relative position vector,the maximum capture distance and the maximum field angle of interceptor seeker.展开更多
A type of three-pitch fluctuating speed ratio limited-slip differential (TPLSD) is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth...A type of three-pitch fluctuating speed ratio limited-slip differential (TPLSD) is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth profile and separated tooth profile design along the pitch line. Performance comparison between vehicles equipped with three-pitch fluctuating speed ratio limited-slip differential and common open differefitial is finished. The data from experiments prove that three-pitch fluctuating speed ratio limited-slip differential can increase the traction of a vehicle, improve its acceleration performance, decrease braking distance and limit sideslip. The basic structure of new differential is the same of open differential, the only difference is that they have different tooth profile, so the new differential has a high performance price.展开更多
The diversity provided by disjoint paths can increase the survivability of communication networks. This paper considers the allocation of network error correction flow on a network that consists of disjoint paths from...The diversity provided by disjoint paths can increase the survivability of communication networks. This paper considers the allocation of network error correction flow on a network that consists of disjoint paths from the source node to the destination node. Specifically, we propose an algorithm of allocating the path-flows to support the given rate with minimum cost. Our analysis shows that the asymptotic time complexity of this algorithm is linearithmic, and this algorithm is optimal in general展开更多
It is well known that erasure coding can be used in storage systems to efficiently store data while protecting against failures. Conventionally, the design of erasure codes has focused on the tradeoff between redundan...It is well known that erasure coding can be used in storage systems to efficiently store data while protecting against failures. Conventionally, the design of erasure codes has focused on the tradeoff between redundancy and reliability. Under this criterion, an maximum distance separable(MDS) code has optimal redundancy. In this paper, we address a new class of MDS array codes for tolerating triple node failures by extending the row di- agonal parity(RDP) code, named the RDDP(row double diagonal parity) code. The RDDP code takes advantages of good perform- ances of the RDP code with balanced I/0. A specific triple-erasure decoding algorithm to reduce decoding complexity is depicted by geometric graph, and it is easily implemented by software and hardware. The theoretical analysis shows that the comprehensive properties of the RDDP code are optimal, such as encoding and decoding efficiency, update efficiency and I/0 balance performance.展开更多
This paper considers the design of a low-complexity and high-performance precoder for multiple-input multiple-output(MIMO)systems.The precoder is designed by combining both nonlinear and non-iterative processing strat...This paper considers the design of a low-complexity and high-performance precoder for multiple-input multiple-output(MIMO)systems.The precoder is designed by combining both nonlinear and non-iterative processing strategies.The proposed nonlin-ear precoding techniques employ a nonlinear constellation precoding technique based on maximum distance sepa-rable codes at the transmitter.We propose to reduce the computational complexity in iterative-based precoding algorithms by using less complex non-iterative singular value decomposition-based joint precoder and decoder pair design.The maximum likelihood detection for the lin-ear MIMO channel is considered.The simulation results showed that the proposed nonlinear and non-iterative precoding schemes outperform the conventional linear MIMO precoder design,even when a reduced-complexity suboptimal strategy is adopted,considering the bit error rate performance.展开更多
基金The Alliance for a Green Revolution in Africa(AGRA)is gratefully acknowledged for financial support of the study through the African Centre for Crop Improvement(ACCI)
文摘Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes.
文摘The capture probability of interceptors has been deeply studied.Firstly,the definition of capture probability is analyzed.It is transformed into calculating the probability that the relative position vector between the target and the interceptor locates in a certain cone.The relative position vector and associated covariance matrix are projected in line-of-sight coordinates,and the 3-dimensional integral of a probability function in a cone is calculated to obtain the capture probability.The integral equation is a complicated expression of probability,and it is simplified to an explicit approximate expression according to some assumptions based on the characteristics of the engineering problems.The approximation precision is analyzed by comparative simulation difference,which indicates that approximate assumptions are reasonable.Utilizing the explicit expression,the characteristics of capture probability are analyzed respectively with the factors,such as the distance between the interceptor and the target,the precision of relative position vector,the maximum capture distance and the maximum field angle of interceptor seeker.
基金supported by Western-Area Transportation-Construction Scientific and Technological Project (No.200331822322)
文摘A type of three-pitch fluctuating speed ratio limited-slip differential (TPLSD) is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth profile and separated tooth profile design along the pitch line. Performance comparison between vehicles equipped with three-pitch fluctuating speed ratio limited-slip differential and common open differefitial is finished. The data from experiments prove that three-pitch fluctuating speed ratio limited-slip differential can increase the traction of a vehicle, improve its acceleration performance, decrease braking distance and limit sideslip. The basic structure of new differential is the same of open differential, the only difference is that they have different tooth profile, so the new differential has a high performance price.
基金supported by the National Key Basic Research and Development (973) Program of China (No. 2013CB329002)the National High-Tech Research and Development (863) Program of China (No. 2014AA01A703)+3 种基金the National Science and Technology Major Project (No. 2013ZX03004007)the Program for New Century Excellent Talents in University (No. NCET13-0321)the International Science and Technology Cooperation Program (No. 2012DFG12010)the Tsinghua Research Funding (No. 2010THZ03-2)
文摘The diversity provided by disjoint paths can increase the survivability of communication networks. This paper considers the allocation of network error correction flow on a network that consists of disjoint paths from the source node to the destination node. Specifically, we propose an algorithm of allocating the path-flows to support the given rate with minimum cost. Our analysis shows that the asymptotic time complexity of this algorithm is linearithmic, and this algorithm is optimal in general
基金Supported by the National Natural Science Foundation of China(60873216)the Key Project of Sichuan Provincial Department of Education(12ZA223)
文摘It is well known that erasure coding can be used in storage systems to efficiently store data while protecting against failures. Conventionally, the design of erasure codes has focused on the tradeoff between redundancy and reliability. Under this criterion, an maximum distance separable(MDS) code has optimal redundancy. In this paper, we address a new class of MDS array codes for tolerating triple node failures by extending the row di- agonal parity(RDP) code, named the RDDP(row double diagonal parity) code. The RDDP code takes advantages of good perform- ances of the RDP code with balanced I/0. A specific triple-erasure decoding algorithm to reduce decoding complexity is depicted by geometric graph, and it is easily implemented by software and hardware. The theoretical analysis shows that the comprehensive properties of the RDDP code are optimal, such as encoding and decoding efficiency, update efficiency and I/0 balance performance.
文摘This paper considers the design of a low-complexity and high-performance precoder for multiple-input multiple-output(MIMO)systems.The precoder is designed by combining both nonlinear and non-iterative processing strategies.The proposed nonlin-ear precoding techniques employ a nonlinear constellation precoding technique based on maximum distance sepa-rable codes at the transmitter.We propose to reduce the computational complexity in iterative-based precoding algorithms by using less complex non-iterative singular value decomposition-based joint precoder and decoder pair design.The maximum likelihood detection for the lin-ear MIMO channel is considered.The simulation results showed that the proposed nonlinear and non-iterative precoding schemes outperform the conventional linear MIMO precoder design,even when a reduced-complexity suboptimal strategy is adopted,considering the bit error rate performance.