With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterati...With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.展开更多
Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts o...Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.展开更多
Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has hei...Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has heightened concerns over the spatial-temporal dynamics of forest decline.Currently,attaining a comprehensive grasp of the underlying patterns and their propelling factors remains a formidable challenge.We collected tree ring samples from a network of 50 sites across the Greater Xing'an Mountains.These samples were subsequently grouped into two distinct clusters,designated as Groups A and B.The percentage change of growth(GC,%)and the proportion of declining sites were utilized to assess forest decline.The decline in tree growth within Larix gmelinii forests exhibits significant regional variation,accompanied by temporal fluctuations even within a given region.Group A exhibited a pronounced increase in frequency(59.26%)of occurrences and encountered more severe declines(21.65%)in tree growth subsequent to the 1990s,contrasting sharply with Group B,which observed lower frequencies(20.00%)and relatively less severe declines(21.02%)prior to the 1980s.The primary impetus underlying the opposite radial growth increments observed in Larix gmelinii trees from the interplay between their differential response to temperatures and wetter climatic conditions,which is significantly influenced by varying stand densities.In cold-dry conditions,low-density forests may experience soil water freezing,exacerbating drought conditions and thereby inhibiting tree growth,in Group B.Trees growth in high-density stands is restrained by warm-wet conditions,in Group A.These results provide new insights into the variability at the southern edge of the boreal forest biome with different responses to density and climate.展开更多
Objective:Inflammation in the central nervous system plays a crucial role in the occurrence and development of sepsis-associated encephalopathy.This study aims to explore the effects of maresin 1(MaR1),an anti-inflamm...Objective:Inflammation in the central nervous system plays a crucial role in the occurrence and development of sepsis-associated encephalopathy.This study aims to explore the effects of maresin 1(MaR1),an anti-inflammatory and pro-resolving lipid mediator,on sepsis-induced neuroinflammation and cognitive impairment.Methods:Mice were randomly assigned to 4 groups:A sham group(sham operation+vehicle),a cecal ligation and puncture(CLP)group(CLP operation+vehicle),a MaR1-LD group(CLP operation+1 ng MaR1),and a MaR1-HD group(CLP operation+10 ng MaR1).MaR1 or vehicle was intraperitoneally administered starting 1 h before CLP operation,then every other day for 7 days.Survival rates were monitored,and serum inflammatory cytokines[tumor necrosis factor alpha(TNF-α),interleukin(IL)-1β,and IL-6]were measured 24 h after operation using enzyme-linked immunosorbent assay(ELISA).Cognitive function was assessed 7 days after operation using the Morris water maze(MWM)test and novel object recognition(NOR)task.The mRNA expression of TNF-α,IL-1β,IL-6,inducible nitric oxide synthase(iNOS),IL-4,IL-10,and arginase 1(Arg1)in cortical and hippocampal tissues was determined by real-time reverse transcription PCR(RT-PCR).Western blotting was used to determine the protein expression of iNOS,Arg1,signal transducer and activator of transcription 6(STAT6),peroxisome proliferator-activated receptor gamma(PPARγ),and phosphorylated STAT6(p-STAT6)in hippocampal tissue.Microglia activation was visualized via immunofluorescence.Mice were also treated with the PPARγantagonist GW9662 to confirm the involvement of this pathway in MaR1’s effects.Results:CLP increased serum levels of TNF-α,IL-1β,and IL-6,and reduced body weight and survival rates(all P<0.05).Both 1 ng and 10 ng doses of MaR1 significantly reduced serum TNF-α,IL-1β,and IL-6 levels,improved body weight,and increased survival rates(all P<0.05).No significant difference in efficacy was observed between the 2 doses(all P>0.05).MWM test and NOR task indicated that CLP impaired spatial learning,which MaR1 mitigated.However,GW9662 partially reversed MaR1’s protective effects.Real-time RTPCR results demonstrated that,compared to the sham group,mRNA expression of TNF-α,IL-1β,and iNOS significantly increased in hippocampal tissues following CLP(all P<0.05),while IL-4,IL-10,and Arg1 showed a slight decrease,though the differences were not statistically significant(all P>0.05).Compared to the CLP group,both 1 ng and 10 ng MaR1 decreased TNF-α,IL-1β,and iNOS mRNA expression in hippocampal tissues and increased IL-4,IL-10,and Arg1 mRNA expression(all P<0.05).Immunofluorescence results indicated a significant increase in Iba1-positive microglia in the hippocampus after CLP compared to the sham group(P<0.05).Administration of 1 ng and 10 ng MaR1 reduced the percentage area of Iba1-positive cells in the hippocampus compared to the CLP group(both P<0.05).Western blotting results showed that,compared to the CLP group,both 1 ng and 10 ng MaR1 down-regulated the iNOS expression,while up-regulated the expression of Arg1,PPARγ,and p-STAT6(all P<0.05).However,the inclusion of GW9662 counteracted the MaR1-induced upregulation of Arg1 and PPARγcompared to the MaR1-LD group(all P<0.05).Conclusion:MaR1 inhibits the classical activation of hippocampal microglia,promotes alternative activation,reduces sepsis-induced neuroinflammation,and improves cognitive decline.展开更多
The decline in groundwater level is a key factor contributing to cover collapse in karst areas.In this study,the model tests and numerical simulations are conducted to reveal the breeding process and formation mechani...The decline in groundwater level is a key factor contributing to cover collapse in karst areas.In this study,the model tests and numerical simulations are conducted to reveal the breeding process and formation mechanism of cover collapse sinkholes caused by the decline of groundwater level in karst area.Firstly,the model tests confirm that the decline of groundwater level generates negative pressure at the lower edge of overlying soil.The negative pressure experiences four distinct phases during the groundwater drawdown process:rapid rise,slow decline,rapid decline,and gradual dissipation.The maximum negative pressure is influenced by the particle size distribution of the overlying soil.Then,the numerical simulations are carried out to investigate the change process of negative pressure caused by the loss of fillers in karst pipe.The simulated results indicate that the rate of groundwater decline and the thickness and initial void ratio of the overlying soil can affect the maximum negative pressure.As groundwater level drops,a negative pressure zone forms underground,causing tensile failure in the surrounding soil and creating an arched soil hole,which weakens the support for the overlying soil.This phenomenon can also lead to the collapse of the overlying soil under its self-weight.Groundwater table decline in karst areas can result in both internal and surface collapses.When the overlying soil is thin,internal and surface collapses occur simultaneously.In contrast,for thick overlying soil,internal collapse happens first,followed by a layer-by-layer collapse,ultimately forming sinkholes.Finally,the breeding process and formation mechanism of the Yujiawan Reservoir sinkholes are discussed.Geological conditions and groundwater level decline significantly affect internal collapse in karst areas,requiring careful consideration from on-site engineers.展开更多
The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and deve...The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and development of shale oil resources.In this study,the production curves of over 30,000 shale oil wells in the Bakken,Eagle Ford(EF)and Permian are systematically analyzed to provide reference and guidance for future shale oil development.To find out the most suitable decline curve models for shale oil wells,fifteen models and a new fitting method are tested on wells with production history over 6 years.Interestingly,all basins show similar results despite of their varieties in geological conditions:stretched exponential production decline(SEPD)+Arps model provides most accurate prediction of estimated ultimate recovery(EUR)for wells with over 2 years'production,while the Arps model can be used before the two years'switch point.With the EUR calculated by decline curve analysis,we further construct simple regression models for different basins to predict the EUR quickly and early.This work helps us better understand the production of shale oil wells,as well as provide important suggestions for the choices of models for shale oil production prediction.展开更多
In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent...In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent and sustainable supply of electricity.A comprehensive review of optimization techniques for economic power dispatching from distributed generations is imperative to identify the most effective strategies for minimizing operational costs while maintaining grid stability and sustainability.The choice of optimization technique for economic power dispatching from DGs depends on a number of factors,such as the size and complexity of the power system,the availability of computational resources,and the specific requirements of the application.Optimization techniques for economic power dispatching from distributed generations(DGs)can be classified into two main categories:(i)Classical optimization techniques,(ii)Heuristic optimization techniques.In classical optimization techniques,the linear programming(LP)model is one of the most popular optimization methods.Utilizing the LP model,power demand and network constraints are met while minimizing the overall cost of generating electricity from DGs.This approach is efficient in determining the best DGs dispatch and is capable of handling challenging optimization issues in the large-scale system including renewables.The quadratic programming(QP)model,a classical optimization technique,is a further popular optimization method,to consider non-linearity.The QP model can take into account the quadratic cost of energy production,with consideration constraints like network capacity,voltage,and frequency.The metaheuristic optimization techniques are also used for economic power dispatching from DGs,which include genetic algorithms(GA),particle swarm optimization(PSO),and ant colony optimization(ACO).Also,Some researchers are developing hybrid optimization techniques that combine elements of classical and heuristic optimization techniques with the incorporation of droop control,predictive control,and fuzzy-based methods.These methods can deal with large-scale systems with many objectives and non-linear,non-convex optimization issues.The most popular approaches are the LP and QP models,while more difficult problems are handled using metaheuristic optimization techniques.In summary,in order to increase efficiency,reduce costs,and ensure a consistent supply of electricity,optimization techniques are essential tools used in economic power dispatching from DGs.展开更多
Structural brain changes indicative of dementia occur up to 20 years before the onset of clinical symptoms. Efforts to modify the disease process after the onset of cognitive symptoms have been unsuccessful in recent ...Structural brain changes indicative of dementia occur up to 20 years before the onset of clinical symptoms. Efforts to modify the disease process after the onset of cognitive symptoms have been unsuccessful in recent years. Thus, future trials must begin during the preclinical phases of the disease before symptom onset. Age related cognitive decline is often the result of two coexisting brain pathologies: Alzheimer's disease(amyloid, tau, and neurodegeneration) and vascular disease. This review article highlights some of the common neuroimaging techniques used to visualize the accumulation of neurodegenerative and vascular pathologies during the preclinical stages of dementia such as structural magnetic resonance imaging, positron emission tomography, and white matter hyperintensities. We also describe some emerging neuroimaging techniques such as arterial spin labeling, diffusion tensor imaging, and quantitative susceptibility mapping. Recent literature suggests that structural imaging may be the most sensitive and cost-effective marker to detect cognitive decline, while molecular positron emission tomography is primarily useful for detecting disease specific pathology later in the disease process. Currently, the presence of vascular disease on magnetic resonance imaging provides a potential target for optimizing vascular risk reduction strategies, and the presence of vascular disease may be useful when combined with molecular and metabolic markers of neurodegeneration for identifying the risk of cognitive impairment.展开更多
The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centenni...The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centennial goal.At the 19th National Congress,it was put forward by the country that the concept of“new generation of the times”for the first time,indicating the training direction and theoretical guidance for the new generation of the times.The new age requires young people to have firm ideals and beliefs,excellent skills,and a great spirit of responsibility.The proposition of cultivating a new generation of the times is a deep exploration and summary of Marx’s theory of“all-round human development,”Lenin’s youth view and the education view of excellent traditional Chinese culture,and the proposition needs to strengthen the leadership of the Party,give play to the leading role of socialist core values,and the youth themselves should actively act to realize the transformation of theoretical and practical results.展开更多
The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of user...The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of users and devices.Researchers in academia and industry are focusing on technological advancements to achieve highspeed transmission,cell planning,and latency reduction to facilitate emerging applications such as virtual reality,the metaverse,smart cities,smart health,and autonomous vehicles.NextG continuously improves its network functionality to support these applications.Multiple input multiple output(MIMO)technology offers spectral efficiency,dependability,and overall performance in conjunctionwithNextG.This article proposes a secure channel estimation technique in MIMO topology using a norm-estimation model to provide comprehensive insights into protecting NextG network components against adversarial attacks.The technique aims to create long-lasting and secure NextG networks using this extended approach.The viability of MIMO applications and modern AI-driven methodologies to combat cybersecurity threats are explored in this research.Moreover,the proposed model demonstrates high performance in terms of reliability and accuracy,with a 20%reduction in the MalOut-RealOut-Diff metric compared to existing state-of-the-art techniques.展开更多
MicroRNA pathway is down-regulated in aged dopaminergic neurons： Parkinson＇s disease （PD） is the most frequent motor neuro- degenerative disorder and is morphologically mainly associated with progressive dopaminer...MicroRNA pathway is down-regulated in aged dopaminergic neurons： Parkinson＇s disease （PD） is the most frequent motor neuro- degenerative disorder and is morphologically mainly associated with progressive dopaminergic neuronal loss in the ventral midbrain.展开更多
Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which...Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which interfaces with various data converters and exchanges data with a backend central processor.However,the streaming readout architecture has become a new paradigm for several experiments benefiting from advancements in data transmission and computing technologies.This paper proposes a scalable distributed waveform generation and digitization system that utilizes fiber optical connections for data transmission between frontend nodes and a central processor.By utilizing transparent transmission on top of the data link layer,the clock and data ports of the converters in the frontend nodes are directly mapped to the FPGA firmware at the backend.This streaming readout architecture reduces the complexity of frontend development and maintains the data conversion in proximity to the detector.Each frontend node uses a local clock for waveform digitization.To translate the timing information of events in each channel into the system clock domain within the backend central processing FPGA,a novel method is proposed and evaluated using a demonstrator system.展开更多
Predicting molecular properties is essential for advancing for advancing drug discovery and design. Recently, Graph Neural Networks (GNNs) have gained prominence due to their ability to capture the complex structural ...Predicting molecular properties is essential for advancing for advancing drug discovery and design. Recently, Graph Neural Networks (GNNs) have gained prominence due to their ability to capture the complex structural and relational information inherent in molecular graphs. Despite their effectiveness, the “black-box” nature of GNNs remains a significant obstacle to their widespread adoption in chemistry, as it hinders interpretability and trust. In this context, several explanation methods based on factual reasoning have emerged. These methods aim to interpret the predictions made by GNNs by analyzing the key features contributing to the prediction. However, these approaches fail to answer critical questions: “How to ensure that the structure-property mapping learned by GNNs is consistent with established domain knowledge”. In this paper, we propose MMGCF, a novel counterfactual explanation framework designed specifically for the prediction of GNN-based molecular properties. MMGCF constructs a hierarchical tree structure on molecular motifs, enabling the systematic generation of counterfactuals through motif perturbations. This framework identifies causally significant motifs and elucidates their impact on model predictions, offering insights into the relationship between structural modifications and predicted properties. Our method demonstrates its effectiveness through comprehensive quantitative and qualitative evaluations of four real-world molecular datasets.展开更多
In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module ...In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.展开更多
Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yi...Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.展开更多
Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic se...Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic sensors,and piezoelectric energy harvesters,typically operating under the assumption of an external elastic wave incidence.Recently,a novel approach that uses defective PnCs as ultrasonic actuators to generate amplified waves has emerged.However,the existing studies are limited to the generation of either longitudinal or bending waves,with no research addressing the concurrent generation of both.Hence,this paper proposes a straightforward methodology for the concurrent generation and amplification of both wave types utilizing defect modes at independent defect-band frequencies.Bimorph piezoelectric elements are attached to the defect,with each element connected to independent external voltage sources.By precisely adjusting the magnitude and temporal phase differences between the voltage sources,concurrently amplified wave generation is achieved.The paper highlights the advantages of the proposed analytical model.This model is both computationally time-efficient and accurate,in comparison with the COMSOL simulation results.For instance,in case studies,the analytical model reduces the computational time from one hour to mere seconds,while maintaining acceptable error rates of 1%in peak frequencies.This concurrent wave-generation methodology opens new avenues for applications in rotating machinery fault diagnosis,structural health monitoring,and medical imaging.展开更多
We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise durin...We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise during the photoelectric detection and analog-digital conversion,the varying of output optical power would change the signal to noise ratio,then impact time delay signature identification and the random bit generation.Our results show that,when the optical power is less than-14 dBm,with the decreasing of the optical power,the actual identified time delay signature degrades and the entropy of the chaotic signal increases.Moreover,the extracted random bit sequence with lower optical power is more easily pass through the randomness testing.展开更多
The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-...The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-static environment,which lead to the low randomness of generated keys.Meanwhile,the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach,which causes low key generation rate.To tackle these issues,we propose a random coefficient-moving product based wireless key generation scheme(RCMP-WKG),where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate nodes.Furthermore,appropriate quantization approaches are used to increase the key generation rate.Moreover,the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper’s mean square error(MSE).The simulation results reveal that the proposed scheme can achieve better performances in key capacity,key inconsistency rate(KIR)and key generation rate(KGR)compared with the prior works in static environment.Besides,the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.展开更多
Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the...Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the generation of cyclists is rarely presented due to its complexity. This paper proposes a perspective-aware and realistic cyclist generation method via object retrieval. Images, semantic maps, and depth labels of objects are first collected from existing datasets, categorized by class and perspective, and calculated by an algorithm newly designed according to imaging principles. During scene generation, objects with the desired class and perspective are retrieved from the collection and inserted into the background, which is then sent to the modified 2D synthesis model to generate images. This pipeline introduces a perspective computing method, utilizes object retrieval to control the perspective accurately, and modifies a diffusion model to achieve high fidelity. Experiments show that our proposal gets a 2.36 Fréchet Inception Distance, which is lower than the competitive methods, indicating a superior realistic expression ability. When these images are used for augmentation in the semantic segmentation task, the performance of ResNet-50 on the target class can be improved by 4.47%. These results demonstrate that the proposed method can be used to generate cyclists in corner cases to augment model training data, further enhancing the perception capability of autonomous vehicles and improving the safety performance of autonomous driving technology.展开更多
Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of...Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.展开更多
基金supported by the Haihe Laboratory of Cell Ecosystem Innovation Foundation,No.22HHXBSS00047(to PL)Graduate Science and Technology Innovation Project of Tianjin,No.2022BKY173(to LZ)Tianjin Municipal Science and Technology Bureau Foundation,No.20201194(to PL).
文摘With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.
基金funded by the National Key Research and Development Plan of China(No.2022YFE0127900)the National Natural Science Foundation of China(Nos.32071558,32171559)+2 种基金the Natural Science Foundation Key Project of Inner Mongolia Autonomous Region,China(No.2023ZD23)the Hulunbuir Science and Technology Plan Project(No.SF2022001)the Fundamental Research Funds of CAF(CAFYBB2023ZA002).
文摘Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.
基金National Nature Science Foundation of China(No.32371871)。
文摘Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has heightened concerns over the spatial-temporal dynamics of forest decline.Currently,attaining a comprehensive grasp of the underlying patterns and their propelling factors remains a formidable challenge.We collected tree ring samples from a network of 50 sites across the Greater Xing'an Mountains.These samples were subsequently grouped into two distinct clusters,designated as Groups A and B.The percentage change of growth(GC,%)and the proportion of declining sites were utilized to assess forest decline.The decline in tree growth within Larix gmelinii forests exhibits significant regional variation,accompanied by temporal fluctuations even within a given region.Group A exhibited a pronounced increase in frequency(59.26%)of occurrences and encountered more severe declines(21.65%)in tree growth subsequent to the 1990s,contrasting sharply with Group B,which observed lower frequencies(20.00%)and relatively less severe declines(21.02%)prior to the 1980s.The primary impetus underlying the opposite radial growth increments observed in Larix gmelinii trees from the interplay between their differential response to temperatures and wetter climatic conditions,which is significantly influenced by varying stand densities.In cold-dry conditions,low-density forests may experience soil water freezing,exacerbating drought conditions and thereby inhibiting tree growth,in Group B.Trees growth in high-density stands is restrained by warm-wet conditions,in Group A.These results provide new insights into the variability at the southern edge of the boreal forest biome with different responses to density and climate.
基金supported by the National Natural Science Foundation (81601728,31500726)the Natural Science Foundation of Hunan Province (2021JJ41002),China。
文摘Objective:Inflammation in the central nervous system plays a crucial role in the occurrence and development of sepsis-associated encephalopathy.This study aims to explore the effects of maresin 1(MaR1),an anti-inflammatory and pro-resolving lipid mediator,on sepsis-induced neuroinflammation and cognitive impairment.Methods:Mice were randomly assigned to 4 groups:A sham group(sham operation+vehicle),a cecal ligation and puncture(CLP)group(CLP operation+vehicle),a MaR1-LD group(CLP operation+1 ng MaR1),and a MaR1-HD group(CLP operation+10 ng MaR1).MaR1 or vehicle was intraperitoneally administered starting 1 h before CLP operation,then every other day for 7 days.Survival rates were monitored,and serum inflammatory cytokines[tumor necrosis factor alpha(TNF-α),interleukin(IL)-1β,and IL-6]were measured 24 h after operation using enzyme-linked immunosorbent assay(ELISA).Cognitive function was assessed 7 days after operation using the Morris water maze(MWM)test and novel object recognition(NOR)task.The mRNA expression of TNF-α,IL-1β,IL-6,inducible nitric oxide synthase(iNOS),IL-4,IL-10,and arginase 1(Arg1)in cortical and hippocampal tissues was determined by real-time reverse transcription PCR(RT-PCR).Western blotting was used to determine the protein expression of iNOS,Arg1,signal transducer and activator of transcription 6(STAT6),peroxisome proliferator-activated receptor gamma(PPARγ),and phosphorylated STAT6(p-STAT6)in hippocampal tissue.Microglia activation was visualized via immunofluorescence.Mice were also treated with the PPARγantagonist GW9662 to confirm the involvement of this pathway in MaR1’s effects.Results:CLP increased serum levels of TNF-α,IL-1β,and IL-6,and reduced body weight and survival rates(all P<0.05).Both 1 ng and 10 ng doses of MaR1 significantly reduced serum TNF-α,IL-1β,and IL-6 levels,improved body weight,and increased survival rates(all P<0.05).No significant difference in efficacy was observed between the 2 doses(all P>0.05).MWM test and NOR task indicated that CLP impaired spatial learning,which MaR1 mitigated.However,GW9662 partially reversed MaR1’s protective effects.Real-time RTPCR results demonstrated that,compared to the sham group,mRNA expression of TNF-α,IL-1β,and iNOS significantly increased in hippocampal tissues following CLP(all P<0.05),while IL-4,IL-10,and Arg1 showed a slight decrease,though the differences were not statistically significant(all P>0.05).Compared to the CLP group,both 1 ng and 10 ng MaR1 decreased TNF-α,IL-1β,and iNOS mRNA expression in hippocampal tissues and increased IL-4,IL-10,and Arg1 mRNA expression(all P<0.05).Immunofluorescence results indicated a significant increase in Iba1-positive microglia in the hippocampus after CLP compared to the sham group(P<0.05).Administration of 1 ng and 10 ng MaR1 reduced the percentage area of Iba1-positive cells in the hippocampus compared to the CLP group(both P<0.05).Western blotting results showed that,compared to the CLP group,both 1 ng and 10 ng MaR1 down-regulated the iNOS expression,while up-regulated the expression of Arg1,PPARγ,and p-STAT6(all P<0.05).However,the inclusion of GW9662 counteracted the MaR1-induced upregulation of Arg1 and PPARγcompared to the MaR1-LD group(all P<0.05).Conclusion:MaR1 inhibits the classical activation of hippocampal microglia,promotes alternative activation,reduces sepsis-induced neuroinflammation,and improves cognitive decline.
基金supported by the Natural Science Foundation of Shandong Province,China(Grant No.ZR2020QE110)the National Natural Science Foundation of China,China(Grant No.52104089).
文摘The decline in groundwater level is a key factor contributing to cover collapse in karst areas.In this study,the model tests and numerical simulations are conducted to reveal the breeding process and formation mechanism of cover collapse sinkholes caused by the decline of groundwater level in karst area.Firstly,the model tests confirm that the decline of groundwater level generates negative pressure at the lower edge of overlying soil.The negative pressure experiences four distinct phases during the groundwater drawdown process:rapid rise,slow decline,rapid decline,and gradual dissipation.The maximum negative pressure is influenced by the particle size distribution of the overlying soil.Then,the numerical simulations are carried out to investigate the change process of negative pressure caused by the loss of fillers in karst pipe.The simulated results indicate that the rate of groundwater decline and the thickness and initial void ratio of the overlying soil can affect the maximum negative pressure.As groundwater level drops,a negative pressure zone forms underground,causing tensile failure in the surrounding soil and creating an arched soil hole,which weakens the support for the overlying soil.This phenomenon can also lead to the collapse of the overlying soil under its self-weight.Groundwater table decline in karst areas can result in both internal and surface collapses.When the overlying soil is thin,internal and surface collapses occur simultaneously.In contrast,for thick overlying soil,internal collapse happens first,followed by a layer-by-layer collapse,ultimately forming sinkholes.Finally,the breeding process and formation mechanism of the Yujiawan Reservoir sinkholes are discussed.Geological conditions and groundwater level decline significantly affect internal collapse in karst areas,requiring careful consideration from on-site engineers.
基金funded by the National Natural Science Foundation of China(Grant No.52374043)the Key Program of National Natural Science Foundation of China(Grant No.52234003)。
文摘The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and development of shale oil resources.In this study,the production curves of over 30,000 shale oil wells in the Bakken,Eagle Ford(EF)and Permian are systematically analyzed to provide reference and guidance for future shale oil development.To find out the most suitable decline curve models for shale oil wells,fifteen models and a new fitting method are tested on wells with production history over 6 years.Interestingly,all basins show similar results despite of their varieties in geological conditions:stretched exponential production decline(SEPD)+Arps model provides most accurate prediction of estimated ultimate recovery(EUR)for wells with over 2 years'production,while the Arps model can be used before the two years'switch point.With the EUR calculated by decline curve analysis,we further construct simple regression models for different basins to predict the EUR quickly and early.This work helps us better understand the production of shale oil wells,as well as provide important suggestions for the choices of models for shale oil production prediction.
文摘In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent and sustainable supply of electricity.A comprehensive review of optimization techniques for economic power dispatching from distributed generations is imperative to identify the most effective strategies for minimizing operational costs while maintaining grid stability and sustainability.The choice of optimization technique for economic power dispatching from DGs depends on a number of factors,such as the size and complexity of the power system,the availability of computational resources,and the specific requirements of the application.Optimization techniques for economic power dispatching from distributed generations(DGs)can be classified into two main categories:(i)Classical optimization techniques,(ii)Heuristic optimization techniques.In classical optimization techniques,the linear programming(LP)model is one of the most popular optimization methods.Utilizing the LP model,power demand and network constraints are met while minimizing the overall cost of generating electricity from DGs.This approach is efficient in determining the best DGs dispatch and is capable of handling challenging optimization issues in the large-scale system including renewables.The quadratic programming(QP)model,a classical optimization technique,is a further popular optimization method,to consider non-linearity.The QP model can take into account the quadratic cost of energy production,with consideration constraints like network capacity,voltage,and frequency.The metaheuristic optimization techniques are also used for economic power dispatching from DGs,which include genetic algorithms(GA),particle swarm optimization(PSO),and ant colony optimization(ACO).Also,Some researchers are developing hybrid optimization techniques that combine elements of classical and heuristic optimization techniques with the incorporation of droop control,predictive control,and fuzzy-based methods.These methods can deal with large-scale systems with many objectives and non-linear,non-convex optimization issues.The most popular approaches are the LP and QP models,while more difficult problems are handled using metaheuristic optimization techniques.In summary,in order to increase efficiency,reduce costs,and ensure a consistent supply of electricity,optimization techniques are essential tools used in economic power dispatching from DGs.
文摘Structural brain changes indicative of dementia occur up to 20 years before the onset of clinical symptoms. Efforts to modify the disease process after the onset of cognitive symptoms have been unsuccessful in recent years. Thus, future trials must begin during the preclinical phases of the disease before symptom onset. Age related cognitive decline is often the result of two coexisting brain pathologies: Alzheimer's disease(amyloid, tau, and neurodegeneration) and vascular disease. This review article highlights some of the common neuroimaging techniques used to visualize the accumulation of neurodegenerative and vascular pathologies during the preclinical stages of dementia such as structural magnetic resonance imaging, positron emission tomography, and white matter hyperintensities. We also describe some emerging neuroimaging techniques such as arterial spin labeling, diffusion tensor imaging, and quantitative susceptibility mapping. Recent literature suggests that structural imaging may be the most sensitive and cost-effective marker to detect cognitive decline, while molecular positron emission tomography is primarily useful for detecting disease specific pathology later in the disease process. Currently, the presence of vascular disease on magnetic resonance imaging provides a potential target for optimizing vascular risk reduction strategies, and the presence of vascular disease may be useful when combined with molecular and metabolic markers of neurodegeneration for identifying the risk of cognitive impairment.
文摘The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centennial goal.At the 19th National Congress,it was put forward by the country that the concept of“new generation of the times”for the first time,indicating the training direction and theoretical guidance for the new generation of the times.The new age requires young people to have firm ideals and beliefs,excellent skills,and a great spirit of responsibility.The proposition of cultivating a new generation of the times is a deep exploration and summary of Marx’s theory of“all-round human development,”Lenin’s youth view and the education view of excellent traditional Chinese culture,and the proposition needs to strengthen the leadership of the Party,give play to the leading role of socialist core values,and the youth themselves should actively act to realize the transformation of theoretical and practical results.
基金funding from King Saud University through Researchers Supporting Project number(RSP2024R387),King Saud University,Riyadh,Saudi Arabia.
文摘The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile networks.These networks are sufficiently scaled to interconnect billions of users and devices.Researchers in academia and industry are focusing on technological advancements to achieve highspeed transmission,cell planning,and latency reduction to facilitate emerging applications such as virtual reality,the metaverse,smart cities,smart health,and autonomous vehicles.NextG continuously improves its network functionality to support these applications.Multiple input multiple output(MIMO)technology offers spectral efficiency,dependability,and overall performance in conjunctionwithNextG.This article proposes a secure channel estimation technique in MIMO topology using a norm-estimation model to provide comprehensive insights into protecting NextG network components against adversarial attacks.The technique aims to create long-lasting and secure NextG networks using this extended approach.The viability of MIMO applications and modern AI-driven methodologies to combat cybersecurity threats are explored in this research.Moreover,the proposed model demonstrates high performance in terms of reliability and accuracy,with a 20%reduction in the MalOut-RealOut-Diff metric compared to existing state-of-the-art techniques.
基金supported by Shanghai Jiao Tong University non-Chinese principal investigators support program AF0800056Sheng Yushou Joint Grant to IAVthe Academy of Finland grants 293392 and 287843,and TEKES 3i Regeneration grant to AD
文摘MicroRNA pathway is down-regulated in aged dopaminergic neurons： Parkinson＇s disease （PD） is the most frequent motor neuro- degenerative disorder and is morphologically mainly associated with progressive dopaminergic neuronal loss in the ventral midbrain.
基金supported by the National Key Research and Development Program of China(No.2022YFA1604703)the National Natural Science Foundation of China(No.12375189)the National Key Research and Development Program of China(No.2021YFA1601300)。
文摘Waveform generation and digitization play essential roles in numerous physics experiments.In traditional distributed systems for large-scale experiments,each frontend node contains an FPGA for data preprocessing,which interfaces with various data converters and exchanges data with a backend central processor.However,the streaming readout architecture has become a new paradigm for several experiments benefiting from advancements in data transmission and computing technologies.This paper proposes a scalable distributed waveform generation and digitization system that utilizes fiber optical connections for data transmission between frontend nodes and a central processor.By utilizing transparent transmission on top of the data link layer,the clock and data ports of the converters in the frontend nodes are directly mapped to the FPGA firmware at the backend.This streaming readout architecture reduces the complexity of frontend development and maintains the data conversion in proximity to the detector.Each frontend node uses a local clock for waveform digitization.To translate the timing information of events in each channel into the system clock domain within the backend central processing FPGA,a novel method is proposed and evaluated using a demonstrator system.
文摘Predicting molecular properties is essential for advancing for advancing drug discovery and design. Recently, Graph Neural Networks (GNNs) have gained prominence due to their ability to capture the complex structural and relational information inherent in molecular graphs. Despite their effectiveness, the “black-box” nature of GNNs remains a significant obstacle to their widespread adoption in chemistry, as it hinders interpretability and trust. In this context, several explanation methods based on factual reasoning have emerged. These methods aim to interpret the predictions made by GNNs by analyzing the key features contributing to the prediction. However, these approaches fail to answer critical questions: “How to ensure that the structure-property mapping learned by GNNs is consistent with established domain knowledge”. In this paper, we propose MMGCF, a novel counterfactual explanation framework designed specifically for the prediction of GNN-based molecular properties. MMGCF constructs a hierarchical tree structure on molecular motifs, enabling the systematic generation of counterfactuals through motif perturbations. This framework identifies causally significant motifs and elucidates their impact on model predictions, offering insights into the relationship between structural modifications and predicted properties. Our method demonstrates its effectiveness through comprehensive quantitative and qualitative evaluations of four real-world molecular datasets.
文摘In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.
基金financially supported by research grants from the Natural Science Foundation of China(52173235,22265010,12204071,62074022)National Key Research and Development Program of China(2022YFB3803300)+2 种基金Youth Talent Support Program of Chongqing(CQYC2021059206)Hainan Province Science and Technology Special Fund(ZDYF2024SHFZ038)Science and Technology Innovation and Improving Project of Army Medical University(No.2021XJS24)。
文摘Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(No.2022R1I1A1A01056406)。
文摘Defective phononic crystals(PnCs)have enabled spatial localization and quantitative amplification of elastic wave energy.Most previous research has focused on applications such as narrow-bandpass filters,ultrasonic sensors,and piezoelectric energy harvesters,typically operating under the assumption of an external elastic wave incidence.Recently,a novel approach that uses defective PnCs as ultrasonic actuators to generate amplified waves has emerged.However,the existing studies are limited to the generation of either longitudinal or bending waves,with no research addressing the concurrent generation of both.Hence,this paper proposes a straightforward methodology for the concurrent generation and amplification of both wave types utilizing defect modes at independent defect-band frequencies.Bimorph piezoelectric elements are attached to the defect,with each element connected to independent external voltage sources.By precisely adjusting the magnitude and temporal phase differences between the voltage sources,concurrently amplified wave generation is achieved.The paper highlights the advantages of the proposed analytical model.This model is both computationally time-efficient and accurate,in comparison with the COMSOL simulation results.For instance,in case studies,the analytical model reduces the computational time from one hour to mere seconds,while maintaining acceptable error rates of 1%in peak frequencies.This concurrent wave-generation methodology opens new avenues for applications in rotating machinery fault diagnosis,structural health monitoring,and medical imaging.
基金Project supported in part by the National Natural Science Foundation of China(Grant Nos.62005129 and 62175116)。
文摘We experimentally analyze the effect of the optical power on the time delay signature identification and the random bit generation in chaotic semiconductor laser with optical feedback.Due to the inevitable noise during the photoelectric detection and analog-digital conversion,the varying of output optical power would change the signal to noise ratio,then impact time delay signature identification and the random bit generation.Our results show that,when the optical power is less than-14 dBm,with the decreasing of the optical power,the actual identified time delay signature degrades and the entropy of the chaotic signal increases.Moreover,the extracted random bit sequence with lower optical power is more easily pass through the randomness testing.
基金supported in part by the National Natural Science Foundation of China(Numbers 62171445,62471477 and 62201592).
文摘The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless channel.However,there are some extremely challenging security scenarios such as static or quasi-static environment,which lead to the low randomness of generated keys.Meanwhile,the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach,which causes low key generation rate.To tackle these issues,we propose a random coefficient-moving product based wireless key generation scheme(RCMP-WKG),where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate nodes.Furthermore,appropriate quantization approaches are used to increase the key generation rate.Moreover,the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper’s mean square error(MSE).The simulation results reveal that the proposed scheme can achieve better performances in key capacity,key inconsistency rate(KIR)and key generation rate(KGR)compared with the prior works in static environment.Besides,the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.
基金supported by the Cultivation Program for Major Scientific Research Projects of Harbin Institute of Technology(ZDXMPY20180109).
文摘Realistic urban scene generation has been extensively studied for the sake of the development of autonomous vehicles. However, the research has primarily focused on the synthesis of vehicles and pedestrians, while the generation of cyclists is rarely presented due to its complexity. This paper proposes a perspective-aware and realistic cyclist generation method via object retrieval. Images, semantic maps, and depth labels of objects are first collected from existing datasets, categorized by class and perspective, and calculated by an algorithm newly designed according to imaging principles. During scene generation, objects with the desired class and perspective are retrieved from the collection and inserted into the background, which is then sent to the modified 2D synthesis model to generate images. This pipeline introduces a perspective computing method, utilizes object retrieval to control the perspective accurately, and modifies a diffusion model to achieve high fidelity. Experiments show that our proposal gets a 2.36 Fréchet Inception Distance, which is lower than the competitive methods, indicating a superior realistic expression ability. When these images are used for augmentation in the semantic segmentation task, the performance of ResNet-50 on the target class can be improved by 4.47%. These results demonstrate that the proposed method can be used to generate cyclists in corner cases to augment model training data, further enhancing the perception capability of autonomous vehicles and improving the safety performance of autonomous driving technology.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174228 and 12274271)。
文摘Two types of bound states in continuum(BICs),symmetry-protected and Brillouin zone folding driven,are identified in hollow Si nanorod arrays.By modulating the direction and distance of the air holes from the center of the nanorods,it is possible to achieve either a single quasi-BIC or three quasi-BICs.The transmission spectra exhibit ultra-narrow lines,and the quasi-BICs demonstrate ultra-high Q factors.Additionally,efficient third-harmonic generation occurs at low pump intensities.The results indicate that the proposed nanostructures of two types of BICs with a flexible modulation hold great potential applications for nonlinear photonic devices.
