开展脉冲重复间隔(Pulse Repetition Interval,PRI)模式识别工作是电子支援系统的一项重要任务。现代复杂电磁环境下,受雷达辐射源部署和接收设备本身影响,雷达脉冲丢失率极高,导致分选后PRI序列调制规律被破坏,现有的PRI模式识别方法...开展脉冲重复间隔(Pulse Repetition Interval,PRI)模式识别工作是电子支援系统的一项重要任务。现代复杂电磁环境下,受雷达辐射源部署和接收设备本身影响,雷达脉冲丢失率极高,导致分选后PRI序列调制规律被破坏,现有的PRI模式识别方法准确率不足。针对上述问题,从PRI序列还原角度出发,并结合PRI序列本质是时序序列的特点,提出GAIN-LSTM(Generative Adversarial Imputation Nets and Long Short Term Memory)网络架构,其先对丢失脉冲位置进行补全操作,恢复PRI调制规律,然后对还原后PRI序列进行调制模式识别。仿真结果表明,提出的GAIN-LSTM网络架构在脉冲丢失率70%时仍保持95%的正确识别率。展开更多
Dynamic coupling modeling and analysis of rotating beams based on the nonlinear Green-Lagrangian strain are introduced in this work.With the reservation of the axial nonlinear strain,there are more coupling terms for ...Dynamic coupling modeling and analysis of rotating beams based on the nonlinear Green-Lagrangian strain are introduced in this work.With the reservation of the axial nonlinear strain,there are more coupling terms for axial and transverse deformations.The discretized dynamic governing equations are obtained by using the finite element method and Lagrange’s equations of the second kind.Time responses are conducted to compare the proposed model with other previous models.The stretching deformation due to rotating motion is observed and calculated by special formulations under dynamic equilibrium.The stretching deformation and the change of the associated equilibrium position are taken into account to analyze the free vibration and frequency response of the rotating beams.Analytical and numerical comparisons show that the proposed model can provide reliable results,while the previous models may lead to imprecise results,especially in high-speed conditions.展开更多
针对8 m和25 m 2种墩高的单线铁路简支梁桥,研究跨数对中间桥墩地震响应的影响程度。采用OpenSEES程序,分别建立2跨,4跨,6跨和8跨共4种不同跨数的桥梁有限元模型。通过不同方向、不同烈度的地震动作用下地震响应的对比分析,确定跨数对...针对8 m和25 m 2种墩高的单线铁路简支梁桥,研究跨数对中间桥墩地震响应的影响程度。采用OpenSEES程序,分别建立2跨,4跨,6跨和8跨共4种不同跨数的桥梁有限元模型。通过不同方向、不同烈度的地震动作用下地震响应的对比分析,确定跨数对中间桥墩地震响应的影响程度。研究结果表明:在纵向地震动作用下,中间桥墩地震响应随跨数的增加而增加,并在跨数多于4跨时增加趋势变缓;在横向地震动作用下,中间桥墩地震响应随跨数的增加而先增加后减小,并在跨数为4跨时达到最大值。以上趋势随着墩高和地震烈度的增加而减小,但在桥墩屈服前后略有波动。因此,在进行单线铁路简支梁桥的普通高度桥墩地震响应分析时,为了同时提高计算精度和计算效率,建模跨数以4跨为宜。展开更多
Qaidam cattle(Bos taurus) is an important endemic breed in Northwest China, which is mainly distributed in the northwest of Qinghai-Tibet Plateau. It has strong adaptive ability to plateau and swamp conditions, such a...Qaidam cattle(Bos taurus) is an important endemic breed in Northwest China, which is mainly distributed in the northwest of Qinghai-Tibet Plateau. It has strong adaptive ability to plateau and swamp conditions, such as cold tolerance and insect resistance. In this study, the first complete mitochondrial genome of Qaidam cattle was reported. The circular double-stranded genome is 16 340 bp in size, and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop region. The overall nucleotide composition is 33.4% A, 27.2% T, 26.0% C and 13.4% G, with a total A +T content of60.6%. The gene order and composition are similar to those of other B. taurus breeds. Molecular phylogenetic analysis indicated that Qaidam cattle was split as an independent clade and nested within Asian cattle breeds.展开更多
Named Data Network(NDN) has caused wide concerns in VANET community because NDN uses a content-centric mechanism that naming content rather than the host. However, integrating NDN into VANET(NDN-VANET) also faces seve...Named Data Network(NDN) has caused wide concerns in VANET community because NDN uses a content-centric mechanism that naming content rather than the host. However, integrating NDN into VANET(NDN-VANET) also faces several challenges including consumer/provider mobile, broadcast storm problem and so on. In this paper, we propose a Bayesian-based Receiver Forwarding Decision(BRFD) scheme to mitigate the broadcast storm problem incurred by interest packets in NDN-VANET. In the BRFD, vehicles received an interest packet are required to make forwarding decisions based on Bayesian decision theory according to current network conditions obtained by neighbor interaction. However, the receiver-forwarding decision in BRFD can also cause a conflict issue because multiple vehicles forward copies of the same packet at the same time. So a back-off mechanism is introduced in BRFD. Experimental results show that the BRFD algorithm has better performance in several aspects in contrast to probability-based forwarding scheme and "bread crumb" routing.展开更多
Ciphertext policy attribute based encryption(CP-ABE)can provide high finegrained access control for cloud storage.However,it needs to solve problems such as property privacy protection,ciphertext search and data updat...Ciphertext policy attribute based encryption(CP-ABE)can provide high finegrained access control for cloud storage.However,it needs to solve problems such as property privacy protection,ciphertext search and data update in the application process.Therefore,based on CP-ABE scheme,this paper proposes a dynamically updatable searchable encryption cloud storage(DUSECS)scheme.Using the characteristics of homomorphic encryption,the encrypted data is compared to achieve efficient hiding policy.Meanwhile,adopting linked list structure,the DUSECS scheme realizes the dynamic data update and integrity detection,and the search encryption against keyword guessing attacks is achieved by combining homomorphic encryption with aggregation algorithm.The analysis of security and performance shows that the scheme is secure and efficient.展开更多
Named Data Network(NDN)is an important instance of future internet architectures.NDN-MANET routing is a hot research area.Link State Advertisements(LSAs)flooding is a common method to obtain network topology during ro...Named Data Network(NDN)is an important instance of future internet architectures.NDN-MANET routing is a hot research area.Link State Advertisements(LSAs)flooding is a common method to obtain network topology during routes establishment.However,LSAs flooding often causes a broadcast storm in high-density MANET.Using a MultiPoint Relay(MPR)set proposed in the Optimized Link State Routing protocol(OLSR)can effectively reduce the number of LSAs in the process of route establishment.So,this solution can solve the broadcast storm.Based on OLSR,we design and implement a novel routing Named-data Optimized Link State Routing protocol(NOLSR)for NDN-MANET.In NOLSR,a new neighbor discovery protocol to establish the MPR set is proposed.Only nodes in the MPR set will forward LSAs so that other nodes can obtain a network topology and further establish the routing table.The neighbor discovery protocol can also avoid the problem of unidirectional links which impacts the performance of a network.Finally,we make a comparative analysis between classic flooding and NOLSR by simulation experiment in an NDN emulator mini-NDN.展开更多
An active and reactive combined spot price model and the corresponding algorithm are introduced in this paper based on the theory of optimal power flow. Different from the traditional economic dispatch in the field of...An active and reactive combined spot price model and the corresponding algorithm are introduced in this paper based on the theory of optimal power flow. Different from the traditional economic dispatch in the field of spot price, the objective function is to minimize generation costs based on pricing reactive power. Then considering the characteristics of wind turbines, processing methods of wind farms in optimal power flow is discussed. Finally, the feasibility of the model and the algorithm is verified through the simulation results of IEEE 30 system.展开更多
Mitochondrial genome has been widely used in species identification and gene conservation.In the present study,the complete mitochondrial genome of Oula sheep(Ovis aries)was determined using next-generation sequencing...Mitochondrial genome has been widely used in species identification and gene conservation.In the present study,the complete mitochondrial genome of Oula sheep(Ovis aries)was determined using next-generation sequencing.This genome was16 618 bp(NCBI accession number:KU575248)and contained 13 protein coding genes,22 transfer RNA genes,two ribosomal RNA genes,and a typical control region.The overall nucleotide composition was 33.7%A,27.4%T,25.8%C,and 13.1%G,with a total A+T content of 61.1%.The phylogenetic analysis of selected sheep breeds showed that Oula sheep were clustered within branch A and originated from approximately 6 ka.This mitochondrial genome will provide valuable information for molecular genetic research of Oula sheep.展开更多
The Przewalski's gazelle,Procapra przewalskii,is one of the most endangered species in China,and is now found only in a single small area around the Lake Qinghai.In this study,the complete mitochondrial genome of ...The Przewalski's gazelle,Procapra przewalskii,is one of the most endangered species in China,and is now found only in a single small area around the Lake Qinghai.In this study,the complete mitochondrial genome of P.przewalskii was determined and annotated.The circular genome is 16 547-bp long,containing13 protein-coding genes,22 transfer RNA genes,2 ribosomal RNA genes,and a predicted control region.The overall base composition was 34.0% A,24.7% C,28.3% T,and 13.0% G,with a total A + T content of 62.3%.Phylogenetic analysis of all 19 Bovidae species indicated that P.przewalskii showed a close relationship to Procapra gutturosa.Our results provide a great deal of useful information on further studies for conservation biology of Przewalski's gazelle.展开更多
In this paper,comprehensively studied inhabit environments,population size,population density and distribution regions on wild yak,the results showed that genetic resource of wild yak has been decreased from 1950'...In this paper,comprehensively studied inhabit environments,population size,population density and distribution regions on wild yak,the results showed that genetic resource of wild yak has been decreased from 1950'to 1980',after that,and its genetic resource began to show increasing trend in nature reserves due to protection measures strengthened.展开更多
文摘开展脉冲重复间隔(Pulse Repetition Interval,PRI)模式识别工作是电子支援系统的一项重要任务。现代复杂电磁环境下,受雷达辐射源部署和接收设备本身影响,雷达脉冲丢失率极高,导致分选后PRI序列调制规律被破坏,现有的PRI模式识别方法准确率不足。针对上述问题,从PRI序列还原角度出发,并结合PRI序列本质是时序序列的特点,提出GAIN-LSTM(Generative Adversarial Imputation Nets and Long Short Term Memory)网络架构,其先对丢失脉冲位置进行补全操作,恢复PRI调制规律,然后对还原后PRI序列进行调制模式识别。仿真结果表明,提出的GAIN-LSTM网络架构在脉冲丢失率70%时仍保持95%的正确识别率。
基金the National Natural Science Foundation of China(Nos.12232012,12202110,12102191,and 12072159)the Fundamental Research Funds for the Central Universities of China(No.30922010314)the Natural Science Foundation of Guangxi Province of China(No.2020GXNSFBA297010)。
文摘Dynamic coupling modeling and analysis of rotating beams based on the nonlinear Green-Lagrangian strain are introduced in this work.With the reservation of the axial nonlinear strain,there are more coupling terms for axial and transverse deformations.The discretized dynamic governing equations are obtained by using the finite element method and Lagrange’s equations of the second kind.Time responses are conducted to compare the proposed model with other previous models.The stretching deformation due to rotating motion is observed and calculated by special formulations under dynamic equilibrium.The stretching deformation and the change of the associated equilibrium position are taken into account to analyze the free vibration and frequency response of the rotating beams.Analytical and numerical comparisons show that the proposed model can provide reliable results,while the previous models may lead to imprecise results,especially in high-speed conditions.
基金Postgraduate Science and Technology Innovation Project of China Civil Aviation University(Y17-34)Basic Research Business Fee Project of Central University in 2016(3122016B004)~~
文摘针对8 m和25 m 2种墩高的单线铁路简支梁桥,研究跨数对中间桥墩地震响应的影响程度。采用OpenSEES程序,分别建立2跨,4跨,6跨和8跨共4种不同跨数的桥梁有限元模型。通过不同方向、不同烈度的地震动作用下地震响应的对比分析,确定跨数对中间桥墩地震响应的影响程度。研究结果表明:在纵向地震动作用下,中间桥墩地震响应随跨数的增加而增加,并在跨数多于4跨时增加趋势变缓;在横向地震动作用下,中间桥墩地震响应随跨数的增加而先增加后减小,并在跨数为4跨时达到最大值。以上趋势随着墩高和地震烈度的增加而减小,但在桥墩屈服前后略有波动。因此,在进行单线铁路简支梁桥的普通高度桥墩地震响应分析时,为了同时提高计算精度和计算效率,建模跨数以4跨为宜。
基金Supported by China Agriculture Research System(CARS-37)Science and Technology Support Projects in Gansu Province(1504NKCA052)+1 种基金Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2014-LIHPS-01)Central Publicinterest Scientific Institution Basal Research Fund(1610322016006)
文摘Qaidam cattle(Bos taurus) is an important endemic breed in Northwest China, which is mainly distributed in the northwest of Qinghai-Tibet Plateau. It has strong adaptive ability to plateau and swamp conditions, such as cold tolerance and insect resistance. In this study, the first complete mitochondrial genome of Qaidam cattle was reported. The circular double-stranded genome is 16 340 bp in size, and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop region. The overall nucleotide composition is 33.4% A, 27.2% T, 26.0% C and 13.4% G, with a total A +T content of60.6%. The gene order and composition are similar to those of other B. taurus breeds. Molecular phylogenetic analysis indicated that Qaidam cattle was split as an independent clade and nested within Asian cattle breeds.
基金supported by NSFC No.61461027,No.61562059Innovation Promotion Education Fund of Ministry of Education 2018A05003Overseas exchange fund for faculty of the Lanzhou University of Technology12。
文摘Named Data Network(NDN) has caused wide concerns in VANET community because NDN uses a content-centric mechanism that naming content rather than the host. However, integrating NDN into VANET(NDN-VANET) also faces several challenges including consumer/provider mobile, broadcast storm problem and so on. In this paper, we propose a Bayesian-based Receiver Forwarding Decision(BRFD) scheme to mitigate the broadcast storm problem incurred by interest packets in NDN-VANET. In the BRFD, vehicles received an interest packet are required to make forwarding decisions based on Bayesian decision theory according to current network conditions obtained by neighbor interaction. However, the receiver-forwarding decision in BRFD can also cause a conflict issue because multiple vehicles forward copies of the same packet at the same time. So a back-off mechanism is introduced in BRFD. Experimental results show that the BRFD algorithm has better performance in several aspects in contrast to probability-based forwarding scheme and "bread crumb" routing.
基金supported by the National Nature Science Foundation of China under grant No.(61562059,61461027,61462060)。
文摘Ciphertext policy attribute based encryption(CP-ABE)can provide high finegrained access control for cloud storage.However,it needs to solve problems such as property privacy protection,ciphertext search and data update in the application process.Therefore,based on CP-ABE scheme,this paper proposes a dynamically updatable searchable encryption cloud storage(DUSECS)scheme.Using the characteristics of homomorphic encryption,the encrypted data is compared to achieve efficient hiding policy.Meanwhile,adopting linked list structure,the DUSECS scheme realizes the dynamic data update and integrity detection,and the search encryption against keyword guessing attacks is achieved by combining homomorphic encryption with aggregation algorithm.The analysis of security and performance shows that the scheme is secure and efficient.
基金supported by NSFC No.61461027,No.61562059Innovation Promotion Education Fund of Ministry of Education 2018A05003Overseas exchange fund for faculty of the Lanzhou University of Technology.We thank the referees for helpful comments.
文摘Named Data Network(NDN)is an important instance of future internet architectures.NDN-MANET routing is a hot research area.Link State Advertisements(LSAs)flooding is a common method to obtain network topology during routes establishment.However,LSAs flooding often causes a broadcast storm in high-density MANET.Using a MultiPoint Relay(MPR)set proposed in the Optimized Link State Routing protocol(OLSR)can effectively reduce the number of LSAs in the process of route establishment.So,this solution can solve the broadcast storm.Based on OLSR,we design and implement a novel routing Named-data Optimized Link State Routing protocol(NOLSR)for NDN-MANET.In NOLSR,a new neighbor discovery protocol to establish the MPR set is proposed.Only nodes in the MPR set will forward LSAs so that other nodes can obtain a network topology and further establish the routing table.The neighbor discovery protocol can also avoid the problem of unidirectional links which impacts the performance of a network.Finally,we make a comparative analysis between classic flooding and NOLSR by simulation experiment in an NDN emulator mini-NDN.
文摘An active and reactive combined spot price model and the corresponding algorithm are introduced in this paper based on the theory of optimal power flow. Different from the traditional economic dispatch in the field of spot price, the objective function is to minimize generation costs based on pricing reactive power. Then considering the characteristics of wind turbines, processing methods of wind farms in optimal power flow is discussed. Finally, the feasibility of the model and the algorithm is verified through the simulation results of IEEE 30 system.
基金Supported by the Central Public-Interest Scientific Institution Basal Research Fund(1610322016006)Science and Technology Support Projects in Gansu Province(1504NKCA052)the Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2014-LIHPS-01)
文摘Mitochondrial genome has been widely used in species identification and gene conservation.In the present study,the complete mitochondrial genome of Oula sheep(Ovis aries)was determined using next-generation sequencing.This genome was16 618 bp(NCBI accession number:KU575248)and contained 13 protein coding genes,22 transfer RNA genes,two ribosomal RNA genes,and a typical control region.The overall nucleotide composition was 33.7%A,27.4%T,25.8%C,and 13.1%G,with a total A+T content of 61.1%.The phylogenetic analysis of selected sheep breeds showed that Oula sheep were clustered within branch A and originated from approximately 6 ka.This mitochondrial genome will provide valuable information for molecular genetic research of Oula sheep.
基金Supported by National Natural Science Foundation of China(31301976)the Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2014-LIHPS-01)
文摘The Przewalski's gazelle,Procapra przewalskii,is one of the most endangered species in China,and is now found only in a single small area around the Lake Qinghai.In this study,the complete mitochondrial genome of P.przewalskii was determined and annotated.The circular genome is 16 547-bp long,containing13 protein-coding genes,22 transfer RNA genes,2 ribosomal RNA genes,and a predicted control region.The overall base composition was 34.0% A,24.7% C,28.3% T,and 13.0% G,with a total A + T content of 62.3%.Phylogenetic analysis of all 19 Bovidae species indicated that P.przewalskii showed a close relationship to Procapra gutturosa.Our results provide a great deal of useful information on further studies for conservation biology of Przewalski's gazelle.
文摘In this paper,comprehensively studied inhabit environments,population size,population density and distribution regions on wild yak,the results showed that genetic resource of wild yak has been decreased from 1950'to 1980',after that,and its genetic resource began to show increasing trend in nature reserves due to protection measures strengthened.