We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that...We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.展开更多
The dynamic multichannel binocular visual image modeling is studied based on Internet of Things (IoT) Perception Layer, using mobile robot self-organizing network. By employing multigroup mobile robots with binocular ...The dynamic multichannel binocular visual image modeling is studied based on Internet of Things (IoT) Perception Layer, using mobile robot self-organizing network. By employing multigroup mobile robots with binocular visual system, the real visual images of the object will be obtained. Then through the mobile self-organizing network, a three-dimensional model is rebuilt by synthesizing the returned images. On this basis, we formalize a novel algorithm for multichannel binocular visual three-dimensional images based on fast three-dimensional modeling. Compared with the method based on single binocular visual system, the new algorithm can improve the Integrity and accuracy of the dynamic three-dimensional object modeling. The simulation results show that the new method can effectively accelerate the modeling speed, improve the similarity and not increase the data size.展开更多
In this paper, we explore the long time behavior of a multigroup Susceptible-Infected Susceptible （SIS） model with stochastic perturbations. The conditions for the disease to die out are obtained. Besides, we also s...In this paper, we explore the long time behavior of a multigroup Susceptible-Infected Susceptible （SIS） model with stochastic perturbations. The conditions for the disease to die out are obtained. Besides, we also show that the disease is fluctuating around the endemic equilibrium under some conditions. Moreover, there is a stationary distribution under stronger conditions. At last, some numerical simulations are applied to support our theoretical results.展开更多
In this paper,we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HlV with saturated incidence rate.We obtainsufficient conditions for the existence and uniqu...In this paper,we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HlV with saturated incidence rate.We obtainsufficient conditions for the existence and uniqueness of an ergodic stationary distribu-tion of positive solutions to the system by establishing a suitable stochastic Lyapunovfunction.In addition,we make up adequate conditions for complete eradication and wip-ing out the infectious disease.In a biological interpretation,the existence of a stationarydistribution implies that the disease will prevail and persist in the long term.Finally,examples and numerical simulations are introduced to validate our theoretical results.展开更多
Background Extreme rainfall and flooding events are projected to increase in frequency and disturb biogeochemical cycles such as the nitrogen(N)cycle.By combining trees and grasses,silvopastoral agroforestry is expect...Background Extreme rainfall and flooding events are projected to increase in frequency and disturb biogeochemical cycles such as the nitrogen(N)cycle.By combining trees and grasses,silvopastoral agroforestry is expected to increase the stability of this cycle in response to flooding.However,little is known about the response of nitrification to flooding in silvopastoral systems.Aim of this study was to assess nitrification stability in response to flooding and identify the main causal relations that drive it in temperate silvopastures.Methods The nitrification stability(i.e.,resistance and resilience)was assessed in two silvopastoral systems(i.e.,hedgerows and alley cropping)at three positions relative to the trees.The resistance and resilience of nitrification potential were measured in the laboratory after four weeks of flooding stress and four weeks after the end of the stress,respectively.For the first time,we used multigroup latent structural equation modeling(ML-SEM)to explore the spatial structure of causal relations between nitrification stability and soil properties across all positions of the two silvopastoral systems.Results Tree rows of both systems favored nitrification resistance,while the mean nitrification potential under flooded conditions was on average 27%and 35%higher as compared to non-stressed soils at the two positions assessed in the grass alleys.ML-SEM revealed that the causal relations that explained these results differed between the two systems.The ML-SEM models tested were unable to explain the causal relations in the hedgerow system.However,the model that considered a covariance between soil physical properties and soil resources availability(model A)was able to explain them in the alley-cropping system.It revealed that causal relations explaining nitrification stability varied according to the position relative to the trees:in the tree rows nitrification stability was associated with higher soil organic carbon concentration and earthworm abundance;in the grass alleys it was associated with higher soil organic carbon concentration and soil bulk density.Conclusions This study indicates that silvopastoral systems help regulate the N cycle near the trees.The results further imply that improvements in soil organic carbon concentration and soil bulk density favor the regulation of N-related processes in grasslands.展开更多
文摘We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.
基金supported by HiTech Researchand Development Program of China under Grant No.2007AA10Z235
文摘The dynamic multichannel binocular visual image modeling is studied based on Internet of Things (IoT) Perception Layer, using mobile robot self-organizing network. By employing multigroup mobile robots with binocular visual system, the real visual images of the object will be obtained. Then through the mobile self-organizing network, a three-dimensional model is rebuilt by synthesizing the returned images. On this basis, we formalize a novel algorithm for multichannel binocular visual three-dimensional images based on fast three-dimensional modeling. Compared with the method based on single binocular visual system, the new algorithm can improve the Integrity and accuracy of the dynamic three-dimensional object modeling. The simulation results show that the new method can effectively accelerate the modeling speed, improve the similarity and not increase the data size.
基金The authors are grateflfl to tile anonymous referees for carefully reading the manuscript and for important snggestions and comments, which led to the improvement of their manuscript. This research is supported by NSFC grant 11601043, China Postdoctoral Science Foundation （Grant No. 2016M590243）, Jiangsu Province ＂333 High-Level Personnel Training Project＂ （Grant No. BRA2017468） and Qing Lan Project of Jiangsu Province of 2016 and 2017.
文摘In this paper, we explore the long time behavior of a multigroup Susceptible-Infected Susceptible （SIS） model with stochastic perturbations. The conditions for the disease to die out are obtained. Besides, we also show that the disease is fluctuating around the endemic equilibrium under some conditions. Moreover, there is a stationary distribution under stronger conditions. At last, some numerical simulations are applied to support our theoretical results.
基金This work is supported by the National Natural Science Foundation of China(Nos.12001090 and 11871473)Shandong Provincial Natural Science Foundation(No.ZR2019MA010)the Fundamental Research Funds for the Central Universitiesof China(No.2412020QD024).
文摘In this paper,we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HlV with saturated incidence rate.We obtainsufficient conditions for the existence and uniqueness of an ergodic stationary distribu-tion of positive solutions to the system by establishing a suitable stochastic Lyapunovfunction.In addition,we make up adequate conditions for complete eradication and wip-ing out the infectious disease.In a biological interpretation,the existence of a stationarydistribution implies that the disease will prevail and persist in the long term.Finally,examples and numerical simulations are introduced to validate our theoretical results.
基金financially supported by La Fondation de France(grant no.00117721/WB-2021-35937).
文摘Background Extreme rainfall and flooding events are projected to increase in frequency and disturb biogeochemical cycles such as the nitrogen(N)cycle.By combining trees and grasses,silvopastoral agroforestry is expected to increase the stability of this cycle in response to flooding.However,little is known about the response of nitrification to flooding in silvopastoral systems.Aim of this study was to assess nitrification stability in response to flooding and identify the main causal relations that drive it in temperate silvopastures.Methods The nitrification stability(i.e.,resistance and resilience)was assessed in two silvopastoral systems(i.e.,hedgerows and alley cropping)at three positions relative to the trees.The resistance and resilience of nitrification potential were measured in the laboratory after four weeks of flooding stress and four weeks after the end of the stress,respectively.For the first time,we used multigroup latent structural equation modeling(ML-SEM)to explore the spatial structure of causal relations between nitrification stability and soil properties across all positions of the two silvopastoral systems.Results Tree rows of both systems favored nitrification resistance,while the mean nitrification potential under flooded conditions was on average 27%and 35%higher as compared to non-stressed soils at the two positions assessed in the grass alleys.ML-SEM revealed that the causal relations that explained these results differed between the two systems.The ML-SEM models tested were unable to explain the causal relations in the hedgerow system.However,the model that considered a covariance between soil physical properties and soil resources availability(model A)was able to explain them in the alley-cropping system.It revealed that causal relations explaining nitrification stability varied according to the position relative to the trees:in the tree rows nitrification stability was associated with higher soil organic carbon concentration and earthworm abundance;in the grass alleys it was associated with higher soil organic carbon concentration and soil bulk density.Conclusions This study indicates that silvopastoral systems help regulate the N cycle near the trees.The results further imply that improvements in soil organic carbon concentration and soil bulk density favor the regulation of N-related processes in grasslands.
