With the rapid development of deep learning algorithms,the computational complexity and functional diversity are increasing rapidly.However,the gap between high computational density and insufficient memory bandwidth ...With the rapid development of deep learning algorithms,the computational complexity and functional diversity are increasing rapidly.However,the gap between high computational density and insufficient memory bandwidth under the traditional von Neumann architecture is getting worse.Analyzing the algorithmic characteristics of convolutional neural network(CNN),it is found that the access characteristics of convolution(CONV)and fully connected(FC)operations are very different.Based on this feature,a dual-mode reronfigurable distributed memory architecture for CNN accelerator is designed.It can be configured in Bank mode or first input first output(FIFO)mode to accommodate the access needs of different operations.At the same time,a programmable memory control unit is designed,which can effectively control the dual-mode configurable distributed memory architecture by using customized special accessing instructions and reduce the data accessing delay.The proposed architecture is verified and tested by parallel implementation of some CNN algorithms.The experimental results show that the peak bandwidth can reach 13.44 GB·s^(-1)at an operating frequency of 120 MHz.This work can achieve 1.40,1.12,2.80 and 4.70 times the peak bandwidth compared with the existing work.展开更多
Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Becau...Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Because the suspected seismogenic faults on the surface, distribution of aftershocks and focal mechanism solutions are not consistent, it remains difficult to determine what is the real causal fault or seismogenic structure for this event. Actually, it may imply the complicity of the seismic source at depth. In addition, the distribution of the co- seismic landslides also exhibits some diffusion that is different from general eases, likely associated with the seismic focus structure.展开更多
This study evaluates the structure and regeneration status of woody species in the Munessa Forest,a dry Afromontane forest in southern Ethiopia.Vegetation data were collected using a systematic sampling method.Density...This study evaluates the structure and regeneration status of woody species in the Munessa Forest,a dry Afromontane forest in southern Ethiopia.Vegetation data were collected using a systematic sampling method.Density and distribution of seedlings,saplings and mature trees were assessed along an altitudinal gradient using quadrats of different sizes.The number of individuals,frequencies,heights and DBH of species>1 m and DBH>2.5 cm were recorded in altitudinal bands of 100 m.Analysis of the vegetation structure shows that the density of woody species decreases as DBH and height class increases.Basal area of stems with DBH>2.5 cm was 53.4 m^(2)ha^(−1).Population structure and regeneration patterns indicate a significant degradation of the forest due to anthropogenic disturbances.Regeneration was better for less valuable woody species than for species with economic and ecological value.This suggests a discontinuous recruitment of these species due to selective cutting of middle and higher diameter classes.Therefore,enrichment planting of high value,endangered species is necessary to maintain them as part of this forest.There is a need to develop and implement an effective forest management plan for sustainable use of these forest resources.展开更多
It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings. The effect of using different code-specified lateral load patterns on the seismic performan...It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings. The effect of using different code-specified lateral load patterns on the seismic performance of fixed-base buildings has been investigated by researchers during the past two decades. However, no investigation has yet been carried out for the case of soil-structure systems. In the present study, through intensive parametric analyses of 21,600 linear and nonlinear MDOF systems and considering five different shear strength and stiffness distribution patterns, including three code-specified patterns as well as uniform and concentric patterns subjected to a group of earthquakes recorded on alluvium and soft soils, the effect of structural characteristics distribution on the strength demand and ductility reduction factor of MDOF fixed-base and soil-structure systems are parametrically investigated. The results of this study show that depending on the level of inelasticity, soil flexibility and number of degrees-of-freedoms (DOFs), structural characteristics distribution can significantly affect the strength demand and ductility reduction factor of MDOF systems. It is also found that at high levels of inelasticity, the ductility reduction factor of low-rise MDOF soil-structure systems could be significantly less than that of fixed-base structures and the reduction is less pronounced as the number of stories increases.展开更多
The wind tunnel simulations of wind loading on a solid structure of revolution with one smooth and five rough surfaces were conducted using wind tunnel tests. Timemean and fluctuating pressure distributions on the sur...The wind tunnel simulations of wind loading on a solid structure of revolution with one smooth and five rough surfaces were conducted using wind tunnel tests. Timemean and fluctuating pressure distributions on the surface were obtained, and the relationships between the roughness Reynolds number and pressure distributions were analyzed and discussed. The results show that increasing the surface roughness can significantly affect the pressure distribution, and the roughness Reynolds numbers play an important role in the change of flow patterns. The three flow patterns of subcritical, critical and supercritical flows can be classified based on the changing patterns of both the mean and the fluctuating pressure distributions. The present study suggests that the wind tunnel results obtained in the supercritical pattern reflect more closely those of full-scale solid structure of revolution at the designed wind speed.展开更多
Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Se...Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species(Neodenticula seminae, Thalassiothrix longissima, Amphiprora hyperborean, Chaetoceros atlanticus, Thalassiosira trifulta, etc.) and eurychoric species(Thalassionema nitzschioides, Ch. compressus, Rhizosolenia styliformis, etc.), and characterized by low abundance, even interspecies abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species(Th.nordenski?ldii, Ch. furcellatus, Ch. socialis, Bacteriosira fragilis, etc.) and eurythermal and euryhaline species(L.danicus, Ch. curvisetus, Coscinodiscus curvatulus, etc.), and it was characterized by high abundance, uneven interspecies allocations, prominent dominant species and low species diversity. Spatial-temporal variation of species composition and abundance of phytoplankton in the Bering Sea was directly controlled by surface circulation,nutrient supply and ice edge.展开更多
The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were...The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were acquired using the brillouin optical time-domain reflectometer through the loading experiments of the composite beam structure. In addition, a finite element model of the composite beam structure was developed to analyze the mechanical responses of the epoxy asphalt mixture using the extended finite element method. The experimental results show that the development of crack propagation becomes instable with the increase of the load, and larger loads will generate deeper cracks. Moreover, the numerical results show that the mechanical response of the crack tip changes with the crack propagation, and the worst areas that subjected to crack damage are located on both sides of the composite beam structure.展开更多
In recent years,deep neural networks have become a fascinating and influential research subject,and they play a critical role in video processing and analytics.Since,video analytics are predominantly hardware centric,...In recent years,deep neural networks have become a fascinating and influential research subject,and they play a critical role in video processing and analytics.Since,video analytics are predominantly hardware centric,exploration of implementing the deep neural networks in the hardware needs its brighter light of research.However,the computational complexity and resource constraints of deep neural networks are increasing exponentially by time.Convolutional neural networks are one of the most popular deep learning architecture especially for image classification and video analytics.But these algorithms need an efficient implement strategy for incorporating more real time computations in terms of handling the videos in the hardware.Field programmable Gate arrays(FPGA)is thought to be more advantageous in implementing the convolutional neural networks when compared to Graphics Processing Unit(GPU)in terms of energy efficient and low computational complexity.But still,an intelligent architecture is required for implementing the CNN in FPGA for processing the videos.This paper introduces a modern high-performance,energy-efficient Bat Pruned Ensembled Convolutional networks(BPEC-CNN)for processing the video in the hardware.The system integrates the Bat Evolutionary Pruned layers for CNN and implements the new shared Distributed Filtering Structures(DFS)for handing the filter layers in CNN with pipelined data-path in FPGA.In addition,the proposed system adopts the hardware-software co-design methodology for an energy efficiency and less computational complexity.The extensive experimentations are carried out using CASIA video datasets with ARTIX-7 FPGA boards(number)and various algorithms centric parameters such as accuracy,sensitivity,specificity and architecture centric parameters such as the power,area and throughput are analyzed.These results are then compared with the existing pruned CNN architectures such as CNN-Prunner in which the proposed architecture has been shown 25%better performance than the existing architectures.展开更多
In order to improve the accuracy of damage region division and eliminate the interference of damage adjacent region,the airframe damage region division method based on the structure tensor dynamic operator is proposed...In order to improve the accuracy of damage region division and eliminate the interference of damage adjacent region,the airframe damage region division method based on the structure tensor dynamic operator is proposed in this paper.The structure tensor feature space is established to represent the local features of damage images.It makes different damage images have the same feature distribution,and transform varied damage region division into consistent process of feature space division.On this basis,the structure tensor dynamic operator generation method is designed.It integrates with bacteria foraging optimization algorithm improved by defining double fitness function and chemotaxis rules,in order to calculate the parameters of dynamic operator generation method and realize the structure tensor feature space division.And then the airframe damage region division is realized.The experimental results on different airframe structure damage images show that compared with traditional threshold division method,the proposed method can improve the division quality.The interference of damage adjacent region is eliminated.The information loss caused by over-segmentation is avoided.And it is efficient in operation,and consistent in process.It also has the applicability to different types of structural damage.展开更多
The environmental regulation of plcoplankton distribution in the northern South China Sea was examined In winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophlc bacteria ...The environmental regulation of plcoplankton distribution in the northern South China Sea was examined In winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophlc bacteria was lower In winter (30, 21, and 780×10^3 cells/cm^3, respectively) than In summer (53, 85, and 1 090×10^3 cells/cm^3, respectively), but the seasonal pattern was opposite for plcoeukaryotlc phytoplankton (4 500 and 3 200 cells/cm^3 In winter and summer, respectively). Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant In the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophlc bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilin content occurred at many stations In the summer. In addition, two different populations of Prochlorococcus were found: (i) small, weakly fluorescing cells in the surface layer; and (ii) larger, strongly fluorescent cells In the deep layer. The distribution pattern of photosynthetic plcoplankton and heterotrophlc bacteria depends on environmental effects and their ecophyslologlcal differences. The distribution of Synechococcus appeared to be related to nutrient availability, whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only plcophytoplankton with a consistent strong relationship with bacteria.展开更多
In this paper,the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is considered.The dynamics of subsystems are second-order...In this paper,the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is considered.The dynamics of subsystems are second-order with similar structures,and the nodes are connected by undirected graphs.The event-triggered mechanisms are not only utilized in the transmission of information from the controllers to the actuators,and from the sensors to the controllers within each agent,but also in the communication between agents.Based on the adaptive backstepping method,extra estimators are introduced to handle the unknown parameters,and the measurement errors that occur during the event-triggered communication are well handled by designing compensating terms for the control signals.The presented distributed event-triggered adaptive control laws can guarantee the boundness of the consensus tracking errors and the Zeno behavior is avoided.Meanwhile,the update frequency of the controllers and the load of communication burden are vastly reduced.The obtained control protocol is further applied to a multi-input multi-output second-order nonlinear multi-agent system,and the simulation results show the effectiveness and advantages of our proposed method.展开更多
This article puts forward a kind of parallel and distributed static augmented scene system structure to improve the performance of real time augmented simulation system. Based on static registration technique, several...This article puts forward a kind of parallel and distributed static augmented scene system structure to improve the performance of real time augmented simulation system. Based on static registration technique, several groups of processing nodes do parallel scene pictures taking, 3D registration and virtual-real merging. Process on different nodes is controlled by uniform synchronization mechanism and network transmitting. Wide field of view image can be obtained from image mosaic operation and displayed by wide view display system. Detailed system architecture, registration algorithm, method how to determine camera position and synchronization mechanism between each process node are introduced. The experiment result can validate the good performance of the designed system.展开更多
We determined the effect of Chinese mitten crab(CMC) pen culture on the quantified spatial distribution of the macrozoobenthic community and sediment nutrients in Lake Yangcheng.Redundancy analysis indicated that wa...We determined the effect of Chinese mitten crab(CMC) pen culture on the quantified spatial distribution of the macrozoobenthic community and sediment nutrients in Lake Yangcheng.Redundancy analysis indicated that water temperature, macrophyte occurrence, sediment type, and crab culture were the main environmental factors that influence the spatiotemporal macrozoobenthic distribution. Macrozoobenthic assemblages in the lake were characterized by eutrophic indicator species. In the most polluted estuaries, the abundance and diversity indices of the whole community and abundance of chironomids and oligochaetes were significantly depressed, and sediment carbon(C) and phosphorus(P) were significantly enhanced compared with those in the western, middle(MB), and eastern basin(EB). Crab culture in this lake had significant effects on the species composition of the macrozoobenthic community in one of three CMC culture pens(CP), and generally depressed the abundance of most chironomid and oligochaete species. Significantly increased diversity, evenness, sediment carbon and nitrogen content, and sediment C:P ratio in the CP were found compared with those in the three basins.However, no conspicuous difference in sediment P content between the CP and the two basins of MB and EB was detected. Our results showed that the enhanced diversity and evenness of macrozoobenthos might be associated with the joint effect of macrophyte planting and crab predation, and macrophyte planting may modify the effects of CMC culture by leading to disproportional accumulation of C and N in the sediment relative to P in the CP of the lake.展开更多
In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equati...In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equation with an additional source term,two model Boltzmann equations for two reduced distribution functions are obtained,each then also having an additional undetermined source term.Under this general framework and using Navier-Stokes-Fourier(NSF)equations as constraints,the structures of the distribution functions are obtained by the leading-order Chapman-Enskog analysis.Next,five basic constraints for the design of the two source terms are obtained in order to recover the NSF system in the continuum limit.These constraints allow for adjustable bulk-to-shear viscosity ratio,Prandtl number as well as a thermal energy source.The specific forms of the two source terms can be determined through proper physical considerations and numerical implementation requirements.By employing the truncated Hermite expansion,one design for the two source terms is proposed.Moreover,three well-known mesoscopic models in the literature are shown to be compatible with these five constraints.In addition,the consistent implementation of boundary conditions is also explored by using the Chapman-Enskog expansion at the NSF order.Finally,based on the higher-order Chapman-Enskog expansion of the distribution functions,we derive the complete analytical expressions for the viscous stress tensor and the heat flux.Some underlying physics can be further explored using the DNS simulation data based on the proposed model.展开更多
Abstract Key distribution patterns (KDPs) are finite incidence structures satisfying a certain property which makes them widely used in minimizing the key storage and ensuring the security of communication between u...Abstract Key distribution patterns (KDPs) are finite incidence structures satisfying a certain property which makes them widely used in minimizing the key storage and ensuring the security of communication between users in a large network. We construct a new KDP using t-design and combine two ω-KDPs to give new (ω- 1)-KDPs, which provide secure communication in a large network and minimize the amount of key storage.展开更多
基金Supported by the National Key R&D Program of China(No.2022ZD0119001)the National Natural Science Foundation of China(No.61834005,61802304)+1 种基金the Education Department of Shaanxi Province(No.22JY060)the Shaanxi Provincial Key Research and Devel-opment Plan(No.2024GX-YBXM-100)。
文摘With the rapid development of deep learning algorithms,the computational complexity and functional diversity are increasing rapidly.However,the gap between high computational density and insufficient memory bandwidth under the traditional von Neumann architecture is getting worse.Analyzing the algorithmic characteristics of convolutional neural network(CNN),it is found that the access characteristics of convolution(CONV)and fully connected(FC)operations are very different.Based on this feature,a dual-mode reronfigurable distributed memory architecture for CNN accelerator is designed.It can be configured in Bank mode or first input first output(FIFO)mode to accommodate the access needs of different operations.At the same time,a programmable memory control unit is designed,which can effectively control the dual-mode configurable distributed memory architecture by using customized special accessing instructions and reduce the data accessing delay.The proposed architecture is verified and tested by parallel implementation of some CNN algorithms.The experimental results show that the peak bandwidth can reach 13.44 GB·s^(-1)at an operating frequency of 120 MHz.This work can achieve 1.40,1.12,2.80 and 4.70 times the peak bandwidth compared with the existing work.
基金supported by the National Natural Science Foundation of China(grant No.41572194)the Institute of Geology,China Earthquake Administration(grant No.IGCEA1604)the National Key Basic Research Program of China(grant No.2013CB733205)
文摘Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Because the suspected seismogenic faults on the surface, distribution of aftershocks and focal mechanism solutions are not consistent, it remains difficult to determine what is the real causal fault or seismogenic structure for this event. Actually, it may imply the complicity of the seismic source at depth. In addition, the distribution of the co- seismic landslides also exhibits some diffusion that is different from general eases, likely associated with the seismic focus structure.
基金supported by the National Key R&D Program of China(2017YFD0600600).
文摘This study evaluates the structure and regeneration status of woody species in the Munessa Forest,a dry Afromontane forest in southern Ethiopia.Vegetation data were collected using a systematic sampling method.Density and distribution of seedlings,saplings and mature trees were assessed along an altitudinal gradient using quadrats of different sizes.The number of individuals,frequencies,heights and DBH of species>1 m and DBH>2.5 cm were recorded in altitudinal bands of 100 m.Analysis of the vegetation structure shows that the density of woody species decreases as DBH and height class increases.Basal area of stems with DBH>2.5 cm was 53.4 m^(2)ha^(−1).Population structure and regeneration patterns indicate a significant degradation of the forest due to anthropogenic disturbances.Regeneration was better for less valuable woody species than for species with economic and ecological value.This suggests a discontinuous recruitment of these species due to selective cutting of middle and higher diameter classes.Therefore,enrichment planting of high value,endangered species is necessary to maintain them as part of this forest.There is a need to develop and implement an effective forest management plan for sustainable use of these forest resources.
文摘It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings. The effect of using different code-specified lateral load patterns on the seismic performance of fixed-base buildings has been investigated by researchers during the past two decades. However, no investigation has yet been carried out for the case of soil-structure systems. In the present study, through intensive parametric analyses of 21,600 linear and nonlinear MDOF systems and considering five different shear strength and stiffness distribution patterns, including three code-specified patterns as well as uniform and concentric patterns subjected to a group of earthquakes recorded on alluvium and soft soils, the effect of structural characteristics distribution on the strength demand and ductility reduction factor of MDOF fixed-base and soil-structure systems are parametrically investigated. The results of this study show that depending on the level of inelasticity, soil flexibility and number of degrees-of-freedoms (DOFs), structural characteristics distribution can significantly affect the strength demand and ductility reduction factor of MDOF systems. It is also found that at high levels of inelasticity, the ductility reduction factor of low-rise MDOF soil-structure systems could be significantly less than that of fixed-base structures and the reduction is less pronounced as the number of stories increases.
文摘The wind tunnel simulations of wind loading on a solid structure of revolution with one smooth and five rough surfaces were conducted using wind tunnel tests. Timemean and fluctuating pressure distributions on the surface were obtained, and the relationships between the roughness Reynolds number and pressure distributions were analyzed and discussed. The results show that increasing the surface roughness can significantly affect the pressure distribution, and the roughness Reynolds numbers play an important role in the change of flow patterns. The three flow patterns of subcritical, critical and supercritical flows can be classified based on the changing patterns of both the mean and the fluctuating pressure distributions. The present study suggests that the wind tunnel results obtained in the supercritical pattern reflect more closely those of full-scale solid structure of revolution at the designed wind speed.
基金The National Natural Science Foundation of China under contract Nos 41306116 and 41506217the Basic Research of the National Department of Science and Technology under contract No.GASI-01-02-04the Polar Science Strategic Research Foundation of China under contract No.20140309
文摘Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species(Neodenticula seminae, Thalassiothrix longissima, Amphiprora hyperborean, Chaetoceros atlanticus, Thalassiosira trifulta, etc.) and eurychoric species(Thalassionema nitzschioides, Ch. compressus, Rhizosolenia styliformis, etc.), and characterized by low abundance, even interspecies abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species(Th.nordenski?ldii, Ch. furcellatus, Ch. socialis, Bacteriosira fragilis, etc.) and eurythermal and euryhaline species(L.danicus, Ch. curvisetus, Coscinodiscus curvatulus, etc.), and it was characterized by high abundance, uneven interspecies allocations, prominent dominant species and low species diversity. Spatial-temporal variation of species composition and abundance of phytoplankton in the Bering Sea was directly controlled by surface circulation,nutrient supply and ice edge.
基金Funded by the National Natural Science Foundation of China(No.51178114)the Fundamental Research Funds for the Central Universities(No.CXLX12_0117)the Scientifi c Research Foundation of Graduate School of Southeast University(No.YBJJ1318)
文摘The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were acquired using the brillouin optical time-domain reflectometer through the loading experiments of the composite beam structure. In addition, a finite element model of the composite beam structure was developed to analyze the mechanical responses of the epoxy asphalt mixture using the extended finite element method. The experimental results show that the development of crack propagation becomes instable with the increase of the load, and larger loads will generate deeper cracks. Moreover, the numerical results show that the mechanical response of the crack tip changes with the crack propagation, and the worst areas that subjected to crack damage are located on both sides of the composite beam structure.
文摘In recent years,deep neural networks have become a fascinating and influential research subject,and they play a critical role in video processing and analytics.Since,video analytics are predominantly hardware centric,exploration of implementing the deep neural networks in the hardware needs its brighter light of research.However,the computational complexity and resource constraints of deep neural networks are increasing exponentially by time.Convolutional neural networks are one of the most popular deep learning architecture especially for image classification and video analytics.But these algorithms need an efficient implement strategy for incorporating more real time computations in terms of handling the videos in the hardware.Field programmable Gate arrays(FPGA)is thought to be more advantageous in implementing the convolutional neural networks when compared to Graphics Processing Unit(GPU)in terms of energy efficient and low computational complexity.But still,an intelligent architecture is required for implementing the CNN in FPGA for processing the videos.This paper introduces a modern high-performance,energy-efficient Bat Pruned Ensembled Convolutional networks(BPEC-CNN)for processing the video in the hardware.The system integrates the Bat Evolutionary Pruned layers for CNN and implements the new shared Distributed Filtering Structures(DFS)for handing the filter layers in CNN with pipelined data-path in FPGA.In addition,the proposed system adopts the hardware-software co-design methodology for an energy efficiency and less computational complexity.The extensive experimentations are carried out using CASIA video datasets with ARTIX-7 FPGA boards(number)and various algorithms centric parameters such as accuracy,sensitivity,specificity and architecture centric parameters such as the power,area and throughput are analyzed.These results are then compared with the existing pruned CNN architectures such as CNN-Prunner in which the proposed architecture has been shown 25%better performance than the existing architectures.
基金the Aviation Science Foundation of China(No.20151067003)。
文摘In order to improve the accuracy of damage region division and eliminate the interference of damage adjacent region,the airframe damage region division method based on the structure tensor dynamic operator is proposed in this paper.The structure tensor feature space is established to represent the local features of damage images.It makes different damage images have the same feature distribution,and transform varied damage region division into consistent process of feature space division.On this basis,the structure tensor dynamic operator generation method is designed.It integrates with bacteria foraging optimization algorithm improved by defining double fitness function and chemotaxis rules,in order to calculate the parameters of dynamic operator generation method and realize the structure tensor feature space division.And then the airframe damage region division is realized.The experimental results on different airframe structure damage images show that compared with traditional threshold division method,the proposed method can improve the division quality.The interference of damage adjacent region is eliminated.The information loss caused by over-segmentation is avoided.And it is efficient in operation,and consistent in process.It also has the applicability to different types of structural damage.
基金Supported by the National Natural Science Foundation of China (90211021, 40506032).Acknowledgements The authors sincerely thank Dr WKW Li (Biological 0ceanography Section, Bedford Institute of 0ceanography, Department of Fisheries and 0ceans, Dartmouth, Nova Scotia, Canada) for helpful advice on the paper and for sharing hydrological and chemical data from synchronous observations by Xiamen University and the South China Sea Branch, S0A. The authors also thank Dr Xin Peng in our team for help with sample preservation.
文摘The environmental regulation of plcoplankton distribution in the northern South China Sea was examined In winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophlc bacteria was lower In winter (30, 21, and 780×10^3 cells/cm^3, respectively) than In summer (53, 85, and 1 090×10^3 cells/cm^3, respectively), but the seasonal pattern was opposite for plcoeukaryotlc phytoplankton (4 500 and 3 200 cells/cm^3 In winter and summer, respectively). Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant In the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophlc bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilin content occurred at many stations In the summer. In addition, two different populations of Prochlorococcus were found: (i) small, weakly fluorescing cells in the surface layer; and (ii) larger, strongly fluorescent cells In the deep layer. The distribution pattern of photosynthetic plcoplankton and heterotrophlc bacteria depends on environmental effects and their ecophyslologlcal differences. The distribution of Synechococcus appeared to be related to nutrient availability, whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only plcophytoplankton with a consistent strong relationship with bacteria.
基金supported by National Key R&D Program of China(No.2018YFA0703800)Science Fund for Creative Research Group of the National Natural Science Foundation of China(No.61621002)。
文摘In this paper,the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is considered.The dynamics of subsystems are second-order with similar structures,and the nodes are connected by undirected graphs.The event-triggered mechanisms are not only utilized in the transmission of information from the controllers to the actuators,and from the sensors to the controllers within each agent,but also in the communication between agents.Based on the adaptive backstepping method,extra estimators are introduced to handle the unknown parameters,and the measurement errors that occur during the event-triggered communication are well handled by designing compensating terms for the control signals.The presented distributed event-triggered adaptive control laws can guarantee the boundness of the consensus tracking errors and the Zeno behavior is avoided.Meanwhile,the update frequency of the controllers and the load of communication burden are vastly reduced.The obtained control protocol is further applied to a multi-input multi-output second-order nonlinear multi-agent system,and the simulation results show the effectiveness and advantages of our proposed method.
基金supported by the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China (10XNF039)
文摘This article puts forward a kind of parallel and distributed static augmented scene system structure to improve the performance of real time augmented simulation system. Based on static registration technique, several groups of processing nodes do parallel scene pictures taking, 3D registration and virtual-real merging. Process on different nodes is controlled by uniform synchronization mechanism and network transmitting. Wide field of view image can be obtained from image mosaic operation and displayed by wide view display system. Detailed system architecture, registration algorithm, method how to determine camera position and synchronization mechanism between each process node are introduced. The experiment result can validate the good performance of the designed system.
基金supported by the Scientific Special Fund of Commonweal Industry (Agriculture) of Finance Ministry (No. nyhyzx07-045)Shanghai University Knowledge Service Platform, Shanghai Ocean University Aquatic Animal Breeding Center (ZF1206)
文摘We determined the effect of Chinese mitten crab(CMC) pen culture on the quantified spatial distribution of the macrozoobenthic community and sediment nutrients in Lake Yangcheng.Redundancy analysis indicated that water temperature, macrophyte occurrence, sediment type, and crab culture were the main environmental factors that influence the spatiotemporal macrozoobenthic distribution. Macrozoobenthic assemblages in the lake were characterized by eutrophic indicator species. In the most polluted estuaries, the abundance and diversity indices of the whole community and abundance of chironomids and oligochaetes were significantly depressed, and sediment carbon(C) and phosphorus(P) were significantly enhanced compared with those in the western, middle(MB), and eastern basin(EB). Crab culture in this lake had significant effects on the species composition of the macrozoobenthic community in one of three CMC culture pens(CP), and generally depressed the abundance of most chironomid and oligochaete species. Significantly increased diversity, evenness, sediment carbon and nitrogen content, and sediment C:P ratio in the CP were found compared with those in the three basins.However, no conspicuous difference in sediment P content between the CP and the two basins of MB and EB was detected. Our results showed that the enhanced diversity and evenness of macrozoobenthos might be associated with the joint effect of macrophyte planting and crab predation, and macrophyte planting may modify the effects of CMC culture by leading to disproportional accumulation of C and N in the sediment relative to P in the CP of the lake.
基金supported by the U.S.National Science Foundation(CNS-1513031,CBET-1706130)the National Natural Science Foundation of China(91852205,91741101&11961131006)+1 种基金the National Numerical Wind Tunnel program,Guangdong Provincial Key Laboratory of Turbulence Research and Applications(2019B21203001)Shenzhen Science&Technology Program(Grant No.KQTD20180411143441009).
文摘In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equation with an additional source term,two model Boltzmann equations for two reduced distribution functions are obtained,each then also having an additional undetermined source term.Under this general framework and using Navier-Stokes-Fourier(NSF)equations as constraints,the structures of the distribution functions are obtained by the leading-order Chapman-Enskog analysis.Next,five basic constraints for the design of the two source terms are obtained in order to recover the NSF system in the continuum limit.These constraints allow for adjustable bulk-to-shear viscosity ratio,Prandtl number as well as a thermal energy source.The specific forms of the two source terms can be determined through proper physical considerations and numerical implementation requirements.By employing the truncated Hermite expansion,one design for the two source terms is proposed.Moreover,three well-known mesoscopic models in the literature are shown to be compatible with these five constraints.In addition,the consistent implementation of boundary conditions is also explored by using the Chapman-Enskog expansion at the NSF order.Finally,based on the higher-order Chapman-Enskog expansion of the distribution functions,we derive the complete analytical expressions for the viscous stress tensor and the heat flux.Some underlying physics can be further explored using the DNS simulation data based on the proposed model.
基金Acknowledgements This work was supported in part by the National Natural Science Foundation of China (Grant No. 61179026) and the Fundamental Research Funds for the Central Universities (No. 3122016L005).
文摘Abstract Key distribution patterns (KDPs) are finite incidence structures satisfying a certain property which makes them widely used in minimizing the key storage and ensuring the security of communication between users in a large network. We construct a new KDP using t-design and combine two ω-KDPs to give new (ω- 1)-KDPs, which provide secure communication in a large network and minimize the amount of key storage.