A gradient system and a skew-gradient system can be merged into a combined gradient system. The differential equations of the combined gradient system are established and its property is studied. If a mechanical syste...A gradient system and a skew-gradient system can be merged into a combined gradient system. The differential equations of the combined gradient system are established and its property is studied. If a mechanical system can be represented as a combined gradient system, the stability of the mechanical system can be studied by using the property of the combined gradient system. Some examples are given to illustrate the applications of the results.展开更多
All types of gradient systems and their properties are discussed. Two problems connected with gradient systems and mechanical systems are studied. One is the direct problem of transforming a mechanical system into a g...All types of gradient systems and their properties are discussed. Two problems connected with gradient systems and mechanical systems are studied. One is the direct problem of transforming a mechanical system into a gradient system, and the other is the inverse problem, which is transforming a gradient system into a mechanical system.展开更多
This paper considers a new approach to solving the problem of quantitative estimation of the microseism energy for underground sources that is based on the synthesis of noise interferometry and the passive seismic met...This paper considers a new approach to solving the problem of quantitative estimation of the microseism energy for underground sources that is based on the synthesis of noise interferometry and the passive seismic method of the gradient system. The selection of a seismic field of the underground sources is considered in an experiment conducted in the Tien Shan region. The peculiarities of approach include the separation of vertical microseisms in the ambient seismic noise field structure according to the data of the seismic gradient system and a passive noise interferometry diagram, where microseisms from the underground sources are used as the seismic signal source. It is shown that the use of noise interferometry and passive seismic gradient system allows using the synchronous microseism recordings in a small number of points for passive medium sensing, and leads to the restoration of unknown energy parameters of the seismic field of underground sources.展开更多
This paper deals with an abstract periodic gradient system in which the gradient is taken with respect to a variable metric. We obtain an existence and uniqueness result via the application of a global inverse theorem.
In this paper, we establish the existence of solutions for gradient systems ofevolution under some type （M） and semi-coerciveness conditions. The main result is appliedin order to solve nonlinear diffusion equations...In this paper, we establish the existence of solutions for gradient systems ofevolution under some type （M） and semi-coerciveness conditions. The main result is appliedin order to solve nonlinear diffusion equations involving nonconvex energies.展开更多
In this paper,the Riemann problem of a Chapman-Jouguet combustion model for the pressure-gradient equations is considered.By analyzing in phase space,existence and uniqueness of the solution to the Riemann problem are...In this paper,the Riemann problem of a Chapman-Jouguet combustion model for the pressure-gradient equations is considered.By analyzing in phase space,existence and uniqueness of the solution to the Riemann problem are obtained constructively under the global entropy conditions.展开更多
Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions ...Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.展开更多
Changes in agricultural land use affect ecosystem services and their interactions.However,the differential influences of agricultural land use transitions under different topographical gradients on ecosystem service i...Changes in agricultural land use affect ecosystem services and their interactions.However,the differential influences of agricultural land use transitions under different topographical gradients on ecosystem service interactions remain poorly understood,which limits the integrated management of agricultural systems.The objectives of this study were to analyze the transitional trends of major agricultural land types across distinct topographical gradients and to probe the differential impacts of these transitions on ecosystem service interactions.Using Hangzhou of China as the study area,the analysis focused on four major agricultural land use types(arable land,orchard,tea garden,and abandoned land).The GTWR model was applied to investigate spatiotemporal non-stationarity in the impacts of their transitions on the ecosystem service trade-offs and synergies.The results showed that during 2010–2020,the agricultural land use pattern in plain areas became more diversified and fragmented,while it shifted towards greater homogeneity and contiguity in hilly and mountainous areas.Between 2010–2015 and 2015–2020,the dominant output type of agricultural land use transition was arable land.The dominant input type in plain areas shifted from arable land to orchard,whereas in hilly and mountainous areas,it was orchard and tea garden.The higher synergy between habitat quality and other ecosystem services primarily occurred in plain areas.Over time,the higher synergy between carbon sequestration and soil retention predominantly shifted from mountainous areas to plain areas.A variety of abandoned types across different topographical gradients fostered synergies by reducing the supply capacity of various ecosystem services.Trade-offs between ecosystem services in hilly and mountainous areas could be alleviated by converting arable land into orchard and tea garden.These findings highlight the importance of adopting differentiated,dynamic,and systematic measures for agricultural spatial development in implementing ecosystem management across different topographical gradients.展开更多
Cyber-physical systems(CPS)represent a sophisticated integration of computational and physical components that power critical applications such as smart manufacturing,healthcare,and autonomous infrastructure.However,t...Cyber-physical systems(CPS)represent a sophisticated integration of computational and physical components that power critical applications such as smart manufacturing,healthcare,and autonomous infrastructure.However,their extensive reliance on internet connectivity makes them increasingly susceptible to cyber threats,potentially leading to operational failures and data breaches.Furthermore,CPS faces significant threats related to unauthorized access,improper management,and tampering of the content it generates.In this paper,we propose an intrusion detection system(IDS)optimized for CPS environments using a hybrid approach by combining a natureinspired feature selection scheme,such as Grey Wolf Optimization(GWO),in connection with the emerging Light Gradient Boosting Machine(LightGBM)classifier,named as GWO-LightGBM.While gradient boosting methods have been explored in prior IDS research,our novelty lies in proposing a hybrid approach targeting CPS-specific operational constraints,such as low-latency response and accurate detection of rare and critical attack types.We evaluate GWO-LightGBM against GWO-XGBoost,GWO-CatBoost,and an artificial neural network(ANN)baseline using the NSL-KDD and CIC-IDS-2017 benchmark datasets.The proposed models are assessed across multiple metrics,including accuracy,precision,recall,and F1-score,with an emphasis on class-wise performance and training efficiency.The proposed GWO-LightGBM model achieves the highest overall accuracy(99.73%)for NSL-KDD and(99.61%)for CIC-IDS-2017,demonstrating superior performance in detecting minority classes such as Remote-to-Local(R2L)and Other attacks—commonly overlooked by other classifiers.Moreover,the proposed model consumes lower training time,highlighting its practical feasibility and scalability for real-time CPS deployment.展开更多
The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic ...The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic field profiles is obtained quantitatively by using Lorentz fit.The results indicate that the gradient value of the magnetic field profile near by the substrate,which is produced by a coil current with 137.7A if a SmCo permanent magnet is equipped under the substrate holder,is the largest;when the SmCo permanent magnet is taken away,the larger one is produced by the coil current with 137.7A and the smallest one produced by a coil current with 115.2A.High deposition rate of a-Si∶H film is observed near by the substrate with high magnetic field gradient.But uneven deposition rate along the radius of the sample holder is also found by infrared analysis technology when sample is deposited in magnetic field profile,which is produced by the coil current with 137.7A if the SmCo permanent magnet is equipped under the substrate holder.展开更多
Two kinds of generalized gradient systems are proposed and the characteristics of the two systems are studied. The conditions under which a holonomic mechanical system can be considered as one of the two generalized g...Two kinds of generalized gradient systems are proposed and the characteristics of the two systems are studied. The conditions under which a holonomic mechanical system can be considered as one of the two generalized gradient systems are obtained. The characteristics of the generalized gradient systems can be used to study the stability of the holonomic system. Some examples are given to illustrate the application of the results.展开更多
The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of th...The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of the skew-gradient system are used to study the properties, especially the stability, of the generalized Birkhoffian system. Some examples are given to illustrate the application of the result.展开更多
The characteristics of stationary and non-stationary skew-gradient systems are studied. The skew-gradient representations of holonomic systems, Birkhoffian systems, generalized Birkhoffian systems, and generalized Ham...The characteristics of stationary and non-stationary skew-gradient systems are studied. The skew-gradient representations of holonomic systems, Birkhoffian systems, generalized Birkhoffian systems, and generalized Hamiltonian systems are given. The characteristics of skew-gradient systems are used to study integration and stability of the solution of constrained mechanical systems. Examples are given to illustrate applications of the result.展开更多
The combined gradient representations for generalized Birkhoffian systems in event space are studied.Firstly,the definitions of six kinds of combined gradient systems and corresponding differential equations are given...The combined gradient representations for generalized Birkhoffian systems in event space are studied.Firstly,the definitions of six kinds of combined gradient systems and corresponding differential equations are given.Secondly,the conditions under which generalized Birkhoffian systems become combined gradient systems are obtained. Finally,the characteristics of combined gradient systems are used to study the stability of generalized Birkhoffian systems in event space. Seven examples are given to illustrate the results.展开更多
Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study,...Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.展开更多
The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insight...The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.展开更多
The Da-Xiao Liangshan mountains are critical ecological function areas and essential ecological barriers in the upper reaches of the Yangtze River in China.This study selected a total of six periods of land use land c...The Da-Xiao Liangshan mountains are critical ecological function areas and essential ecological barriers in the upper reaches of the Yangtze River in China.This study selected a total of six periods of land use land cover(LULC)data from 1995 to 2020,to estimate the ecosystem service value(ESV)and analyzed its spatiotemporal evolution and topographic gradient divergence.The results showed that:(1)The ESV increased by 1.1 billion yuan,with an increase rate of 1.47%from 1995 to 2020.Two time periods,2005–2010 and 2015–2020,showed more significant increases than other periods.(2)The elevation and slope of mountainous areas determine the type of land use and further influence the spatial pattern of ESV.(3)Although woodland and grassland are the main land use types of the study area(more than 90%),the hydrological regulation function of the water area partially compensated for the impact of the encroachment of the built-up area on the ESV of grassland.(4)The spatial distribution of ESVs showed an inverted V-shaped characteristic as the topographic gradient increased,with the dominant position being the 5th topographic gradient zone.Finally,this study provided relevant recommendations for ecosystem protection and optimization.The findings of this study clarified the influence of topographical factors on the spatial differentiation of ESV and provided novel insights into ecosystem protection.展开更多
BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)is placed important role in the therapy of complications of portal hypertension,there is still no suitable criterion for a reduction in portosystemic gradi...BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)is placed important role in the therapy of complications of portal hypertension,there is still no suitable criterion for a reduction in portosystemic gradient(PSG),which can both reduce PSG and maximize clinical results and minimize hepatic encephalopathy(HE).AIM To compare the clinical outcomes and incidence of HE after one-third PSG reduction during TIPS in patients with variceal bleeding and refractory ascites.METHODS A total of 1280 patients with portal-hypertension-related complications of refractory ascites or variceal bleeding who underwent TIPS from January 2016 to January 2019 were analyzed retrospectively.Patients were divided into group A(variceal hemorrhage and PSG reduced by one third,n=479);group B(variceal hemorrhage and PSG reduced to<12 mmHg,n=412);group C(refractory ascites and PSG reduced by one third,n=217);and group D(refractory ascites and PSG reduced to<12 mmHg of PSG,plus medication,n=172).The clinical outcomes were analyzed.RESULTS By the endpoint of follow-up,recurrent bleeding was no different between groups A and B(χ^(2)=7.062,P=0.374),but recurrent ascites did differ significantly between groups C and D(χ^(2)=14.493,P=0.006).The probability of total hepatic impairment within 3 years was significantly different between groups A and B(χ^(2)=11.352,P=0.005)and groups C and D(χ^(2)=13.758,P=0.002).The total incidence of HE differed significantly between groups A and B(χ^(2)=7.932,P=0.016),groups C and D(χ^(2)=13.637,P=0.007).There were no differences of survival rate between groups A and B(χ^(2)=3.376,P=0.369,log-rank test),but did differ significantly between groups C and D(χ^(2)=13.582,P=0.014,log-rank test).CONCLUSION The PSG reduction by one third may reduce the risk of HE,hepatic function damage and achieve good clinical results.展开更多
We systematically investigate the polarization gradient cooling （PGC） process in an optical molasses of ultracold cesium atoms. The SR mode for changing the cooling laser, which means that the cooling laser frequenc...We systematically investigate the polarization gradient cooling （PGC） process in an optical molasses of ultracold cesium atoms. The SR mode for changing the cooling laser, which means that the cooling laser frequency is stepped to the setting value while its intensity is ramped, is found to be the best for the PGC, compared with other modes studied. We verify that the heating effect of the cold atoms, which appears when the cooling laser intensity is lower than the saturation intensity, arises from insufficient polarization gradient cooling. Finally, an exponential decay function with a statistical explanation is introduced to explain the dependence of the cold atom temperature on the PGC interaction time.展开更多
This paper explores a highly accurate identification modeling approach for the ship maneuvering motion with fullscale trial. A multi-innovation gradient iterative(MIGI) approach is proposed to optimize the distance me...This paper explores a highly accurate identification modeling approach for the ship maneuvering motion with fullscale trial. A multi-innovation gradient iterative(MIGI) approach is proposed to optimize the distance metric of locally weighted learning(LWL), and a novel non-parametric modeling technique is developed for a nonlinear ship maneuvering system. This proposed method’s advantages are as follows: first, it can avoid the unmodeled dynamics and multicollinearity inherent to the conventional parametric model; second, it eliminates the over-learning or underlearning and obtains the optimal distance metric; and third, the MIGI is not sensitive to the initial parameter value and requires less time during the training phase. These advantages result in a highly accurate mathematical modeling technique that can be conveniently implemented in applications. To verify the characteristics of this mathematical model, two examples are used as the model platforms to study the ship maneuvering.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11372169 and 11272050)
文摘A gradient system and a skew-gradient system can be merged into a combined gradient system. The differential equations of the combined gradient system are established and its property is studied. If a mechanical system can be represented as a combined gradient system, the stability of the mechanical system can be studied by using the property of the combined gradient system. Some examples are given to illustrate the applications of the results.
基金supported by the National Natural Science Foundation of China (Grant 11272050)
文摘All types of gradient systems and their properties are discussed. Two problems connected with gradient systems and mechanical systems are studied. One is the direct problem of transforming a mechanical system into a gradient system, and the other is the inverse problem, which is transforming a gradient system into a mechanical system.
基金The data processing programs,development and implementation of the gradient array system are partially performed with the grant support from the Russian Foundation for Basic Research(No.20-05-00475)The subjects relating to the correlation of geophysical parameters with the average stress-strain behaviour of the geological environment are explored within the Russian State Governmental Task of the Research Station of the Russian Academy of Sciences(No.AAAA-A19-119020190063-2)。
文摘This paper considers a new approach to solving the problem of quantitative estimation of the microseism energy for underground sources that is based on the synthesis of noise interferometry and the passive seismic method of the gradient system. The selection of a seismic field of the underground sources is considered in an experiment conducted in the Tien Shan region. The peculiarities of approach include the separation of vertical microseisms in the ambient seismic noise field structure according to the data of the seismic gradient system and a passive noise interferometry diagram, where microseisms from the underground sources are used as the seismic signal source. It is shown that the use of noise interferometry and passive seismic gradient system allows using the synchronous microseism recordings in a small number of points for passive medium sensing, and leads to the restoration of unknown energy parameters of the seismic field of underground sources.
文摘This paper deals with an abstract periodic gradient system in which the gradient is taken with respect to a variable metric. We obtain an existence and uniqueness result via the application of a global inverse theorem.
文摘In this paper, we establish the existence of solutions for gradient systems ofevolution under some type （M） and semi-coerciveness conditions. The main result is appliedin order to solve nonlinear diffusion equations involving nonconvex energies.
基金Project supported by the National Natural Science Foundation of China (Grant No.10971130)and the Shanghai Leading Academic Discipline Project (Grant No.J50101)
文摘In this paper,the Riemann problem of a Chapman-Jouguet combustion model for the pressure-gradient equations is considered.By analyzing in phase space,existence and uniqueness of the solution to the Riemann problem are obtained constructively under the global entropy conditions.
基金supported by the Fundamental Research Funds of Chinese Academy of Forestry(Nos.CAFYBB2022SY037,CAFYBB2021ZA002 and CAFYBB2022QC002)the Basic Research Foundation of Yunnan Province(Grant No.202201AT070264).
文摘Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.
基金supported by the National Natural Science Foundation of China(42201281,42471320 and 42407652)the Natural Science Foundation of Anhui Province,China(2208085QD102)。
文摘Changes in agricultural land use affect ecosystem services and their interactions.However,the differential influences of agricultural land use transitions under different topographical gradients on ecosystem service interactions remain poorly understood,which limits the integrated management of agricultural systems.The objectives of this study were to analyze the transitional trends of major agricultural land types across distinct topographical gradients and to probe the differential impacts of these transitions on ecosystem service interactions.Using Hangzhou of China as the study area,the analysis focused on four major agricultural land use types(arable land,orchard,tea garden,and abandoned land).The GTWR model was applied to investigate spatiotemporal non-stationarity in the impacts of their transitions on the ecosystem service trade-offs and synergies.The results showed that during 2010–2020,the agricultural land use pattern in plain areas became more diversified and fragmented,while it shifted towards greater homogeneity and contiguity in hilly and mountainous areas.Between 2010–2015 and 2015–2020,the dominant output type of agricultural land use transition was arable land.The dominant input type in plain areas shifted from arable land to orchard,whereas in hilly and mountainous areas,it was orchard and tea garden.The higher synergy between habitat quality and other ecosystem services primarily occurred in plain areas.Over time,the higher synergy between carbon sequestration and soil retention predominantly shifted from mountainous areas to plain areas.A variety of abandoned types across different topographical gradients fostered synergies by reducing the supply capacity of various ecosystem services.Trade-offs between ecosystem services in hilly and mountainous areas could be alleviated by converting arable land into orchard and tea garden.These findings highlight the importance of adopting differentiated,dynamic,and systematic measures for agricultural spatial development in implementing ecosystem management across different topographical gradients.
基金supported by Culture,Sports and Tourism R&D Program through the Korea Creative Content Agency grant funded by the Ministry of Culture,Sports and Tourism in 2024(Project Name:Global Talent Training Program for Copyright Management Technology in Game Contents,Project Number:RS-2024-00396709,Contribution Rate:100%).
文摘Cyber-physical systems(CPS)represent a sophisticated integration of computational and physical components that power critical applications such as smart manufacturing,healthcare,and autonomous infrastructure.However,their extensive reliance on internet connectivity makes them increasingly susceptible to cyber threats,potentially leading to operational failures and data breaches.Furthermore,CPS faces significant threats related to unauthorized access,improper management,and tampering of the content it generates.In this paper,we propose an intrusion detection system(IDS)optimized for CPS environments using a hybrid approach by combining a natureinspired feature selection scheme,such as Grey Wolf Optimization(GWO),in connection with the emerging Light Gradient Boosting Machine(LightGBM)classifier,named as GWO-LightGBM.While gradient boosting methods have been explored in prior IDS research,our novelty lies in proposing a hybrid approach targeting CPS-specific operational constraints,such as low-latency response and accurate detection of rare and critical attack types.We evaluate GWO-LightGBM against GWO-XGBoost,GWO-CatBoost,and an artificial neural network(ANN)baseline using the NSL-KDD and CIC-IDS-2017 benchmark datasets.The proposed models are assessed across multiple metrics,including accuracy,precision,recall,and F1-score,with an emphasis on class-wise performance and training efficiency.The proposed GWO-LightGBM model achieves the highest overall accuracy(99.73%)for NSL-KDD and(99.61%)for CIC-IDS-2017,demonstrating superior performance in detecting minority classes such as Remote-to-Local(R2L)and Other attacks—commonly overlooked by other classifiers.Moreover,the proposed model consumes lower training time,highlighting its practical feasibility and scalability for real-time CPS deployment.
文摘The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic field profiles is obtained quantitatively by using Lorentz fit.The results indicate that the gradient value of the magnetic field profile near by the substrate,which is produced by a coil current with 137.7A if a SmCo permanent magnet is equipped under the substrate holder,is the largest;when the SmCo permanent magnet is taken away,the larger one is produced by the coil current with 137.7A and the smallest one produced by a coil current with 115.2A.High deposition rate of a-Si∶H film is observed near by the substrate with high magnetic field gradient.But uneven deposition rate along the radius of the sample holder is also found by infrared analysis technology when sample is deposited in magnetic field profile,which is produced by the coil current with 137.7A if the SmCo permanent magnet is equipped under the substrate holder.
基金supported by the National Natural Science Foundation of China(Grant No.11272050)
文摘Two kinds of generalized gradient systems are proposed and the characteristics of the two systems are studied. The conditions under which a holonomic mechanical system can be considered as one of the two generalized gradient systems are obtained. The characteristics of the generalized gradient systems can be used to study the stability of the holonomic system. Some examples are given to illustrate the application of the results.
基金Project supported by the National Natural Science Foundation of China(Grant No.11272050)
文摘The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of the skew-gradient system are used to study the properties, especially the stability, of the generalized Birkhoffian system. Some examples are given to illustrate the application of the result.
基金supported by the National Natural Science Foundation of China(Nos.10932002 and 11272050)
文摘The characteristics of stationary and non-stationary skew-gradient systems are studied. The skew-gradient representations of holonomic systems, Birkhoffian systems, generalized Birkhoffian systems, and generalized Hamiltonian systems are given. The characteristics of skew-gradient systems are used to study integration and stability of the solution of constrained mechanical systems. Examples are given to illustrate applications of the result.
基金supported by the National Natural Science Foundation of China(No.11972241)the Natural Science Foundation of Jiangsu Province (No.BK20191454)the Scientific Research Foundation of Suzhou University of Science and Technology (No.XKZ2017005)。
文摘The combined gradient representations for generalized Birkhoffian systems in event space are studied.Firstly,the definitions of six kinds of combined gradient systems and corresponding differential equations are given.Secondly,the conditions under which generalized Birkhoffian systems become combined gradient systems are obtained. Finally,the characteristics of combined gradient systems are used to study the stability of generalized Birkhoffian systems in event space. Seven examples are given to illustrate the results.
基金funded by the Korea Green Promotion Agency, Korea Forest Service
文摘Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.
文摘The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.
基金supported by the National Natural Science Foundation of China(Grant No.52078423)the Sichuan Province Science and Technology Support Program(Grant No.2020YFS0309 and 2020YFS0054)+1 种基金the China Engineering Science and Technology Strategic Consulting Project(Grant No.2022JDR0356)the Key Research Institution of Philosophy and Social Sciences in Sichuan Province:Research Center of National Parks(Grant No.GJGY2023-YB001)。
文摘The Da-Xiao Liangshan mountains are critical ecological function areas and essential ecological barriers in the upper reaches of the Yangtze River in China.This study selected a total of six periods of land use land cover(LULC)data from 1995 to 2020,to estimate the ecosystem service value(ESV)and analyzed its spatiotemporal evolution and topographic gradient divergence.The results showed that:(1)The ESV increased by 1.1 billion yuan,with an increase rate of 1.47%from 1995 to 2020.Two time periods,2005–2010 and 2015–2020,showed more significant increases than other periods.(2)The elevation and slope of mountainous areas determine the type of land use and further influence the spatial pattern of ESV.(3)Although woodland and grassland are the main land use types of the study area(more than 90%),the hydrological regulation function of the water area partially compensated for the impact of the encroachment of the built-up area on the ESV of grassland.(4)The spatial distribution of ESVs showed an inverted V-shaped characteristic as the topographic gradient increased,with the dominant position being the 5th topographic gradient zone.Finally,this study provided relevant recommendations for ecosystem protection and optimization.The findings of this study clarified the influence of topographical factors on the spatial differentiation of ESV and provided novel insights into ecosystem protection.
文摘BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)is placed important role in the therapy of complications of portal hypertension,there is still no suitable criterion for a reduction in portosystemic gradient(PSG),which can both reduce PSG and maximize clinical results and minimize hepatic encephalopathy(HE).AIM To compare the clinical outcomes and incidence of HE after one-third PSG reduction during TIPS in patients with variceal bleeding and refractory ascites.METHODS A total of 1280 patients with portal-hypertension-related complications of refractory ascites or variceal bleeding who underwent TIPS from January 2016 to January 2019 were analyzed retrospectively.Patients were divided into group A(variceal hemorrhage and PSG reduced by one third,n=479);group B(variceal hemorrhage and PSG reduced to<12 mmHg,n=412);group C(refractory ascites and PSG reduced by one third,n=217);and group D(refractory ascites and PSG reduced to<12 mmHg of PSG,plus medication,n=172).The clinical outcomes were analyzed.RESULTS By the endpoint of follow-up,recurrent bleeding was no different between groups A and B(χ^(2)=7.062,P=0.374),but recurrent ascites did differ significantly between groups C and D(χ^(2)=14.493,P=0.006).The probability of total hepatic impairment within 3 years was significantly different between groups A and B(χ^(2)=11.352,P=0.005)and groups C and D(χ^(2)=13.758,P=0.002).The total incidence of HE differed significantly between groups A and B(χ^(2)=7.932,P=0.016),groups C and D(χ^(2)=13.637,P=0.007).There were no differences of survival rate between groups A and B(χ^(2)=3.376,P=0.369,log-rank test),but did differ significantly between groups C and D(χ^(2)=13.582,P=0.014,log-rank test).CONCLUSION The PSG reduction by one third may reduce the risk of HE,hepatic function damage and achieve good clinical results.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB921603 and 2010CB923103)the International Science &Technology Cooperation Program of China(Grant No.2011DFA12490)+2 种基金the National Natural Science Foundation of China(Grant Nos.11304189,61378015,and 61275209)the Project for Excellent Research Team of the National Natural Science Foundation of China(Grant No.61121064)the Program for Changjiang Scholars,China,and the Innovative Research Team in University,China(Grant No.IRT13076)
文摘We systematically investigate the polarization gradient cooling （PGC） process in an optical molasses of ultracold cesium atoms. The SR mode for changing the cooling laser, which means that the cooling laser frequency is stepped to the setting value while its intensity is ramped, is found to be the best for the PGC, compared with other modes studied. We verify that the heating effect of the cold atoms, which appears when the cooling laser intensity is lower than the saturation intensity, arises from insufficient polarization gradient cooling. Finally, an exponential decay function with a statistical explanation is introduced to explain the dependence of the cold atom temperature on the PGC interaction time.
基金financially supported in part by the National High Technology Research and Development Program of China(863Program,Grant No.2015AA016404)the National Natural Science Foundation of China(Grant Nos.51109020,51179019 and 51779029)the Fundamental Research Program for Key Laboratory of the Education Department of Liaoning Province(Grant No.LZ2015006)
文摘This paper explores a highly accurate identification modeling approach for the ship maneuvering motion with fullscale trial. A multi-innovation gradient iterative(MIGI) approach is proposed to optimize the distance metric of locally weighted learning(LWL), and a novel non-parametric modeling technique is developed for a nonlinear ship maneuvering system. This proposed method’s advantages are as follows: first, it can avoid the unmodeled dynamics and multicollinearity inherent to the conventional parametric model; second, it eliminates the over-learning or underlearning and obtains the optimal distance metric; and third, the MIGI is not sensitive to the initial parameter value and requires less time during the training phase. These advantages result in a highly accurate mathematical modeling technique that can be conveniently implemented in applications. To verify the characteristics of this mathematical model, two examples are used as the model platforms to study the ship maneuvering.
