A new class of reflected backward stochastic differential equations (RBSDEs) driven by Teugels martingales associated with Lévy process and Countable Brownian Motions are investigated. Via approximation, the exis...A new class of reflected backward stochastic differential equations (RBSDEs) driven by Teugels martingales associated with Lévy process and Countable Brownian Motions are investigated. Via approximation, the existence and uniqueness of solution to this kind of RBSDEs are obtained.展开更多
The purpose of this contribution is to lay down a preparatory groundwork for an ontology of ecosystem services in the setting of agroecosystems viewed as social-ecological systems. This ontology aims at defining a set...The purpose of this contribution is to lay down a preparatory groundwork for an ontology of ecosystem services in the setting of agroecosystems viewed as social-ecological systems. This ontology aims at defining a set of representational primitives with which to model agroecosystems, through the prism of ecosystem service flows to and from agriculture. It helps delineate between biophysical structures, processes, functions, and ecosystem services. On the human side of agroecosystems, the ontology includes a conceptualization of the behaviors that govern the management of ecosystem services at different levels. It strengthens the existing analytic basis of multidisciplinary research on ecosystem services in agroecosystems by prompting modelers to stick to a homogeneous dynamic-system decomposition of the target agroecosystem. Most importantly, it provides the conceptual link between biophysical research on ecosystem services and equally important considerations on cognitive and social aspects involved in agricultural and landscape-level decisions that aim at implementing agroecological principles.展开更多
This work concerns a dynamic modeling and a numerical simulation of the operation of an adsorption solar refrigeration system using the zeolite-water couple. For this, a mathematical model representing the evolution o...This work concerns a dynamic modeling and a numerical simulation of the operation of an adsorption solar refrigeration system using the zeolite-water couple. For this, a mathematical model representing the evolution of heat and mass transfer at each component of the solar adsorption refrigerator has been developed. We have adopted the Dubinin-Astakhov model for the adsorption kinetics of the zeolite/water pair. This model allows to describe the phenomenon of adsorption and to calculate the rate of adsorbate (water) in the zeolite (adsorbent) as a function of the temperature and the pressure. The equations governing the operation of the solar adsorption refrigerator, deduced from the thermal and mass balances established at the collector adsorber, condenser and evaporator components, were solved by an implicit finite difference scheme and Gauss Seidel’s iterative method. We have validated the model established by applying it to the model of Allouhi et al. 2014. We analyzed the influence of the adsorbate/adsorbent couples, the solar flux, the ambient temperature on the adsorption and desorption process. The temperature profiles obtained representing the temperature evolution of the glass, the absorbent plate, the zeolite-water mixture, the condenser, the evaporator, as well as the pressure and the adsorbed mass allowed us to evaluate the performance of the solar adsorption refrigerator. SCOP is higher the higher the solar flux captured by the collector-adsorber.展开更多
This work studies the influence of mechanical and geometrical characteristics of the concrete and the soil on the stresses in a mat foundation. In this study, the soil-structure interaction is modeled by two parameter...This work studies the influence of mechanical and geometrical characteristics of the concrete and the soil on the stresses in a mat foundation. In this study, the soil-structure interaction is modeled by two parameters, the modulus of subgrade vertical reaction (k) and the modulus of subgrade horizontal reaction (2T). These two parameters are dependent on the geometrical and mechanical characteristics of the system. Results of this study show a sensitivity of solicitations to variations of geometrical and mechanical characteristics of the model. Although solicitations in the plate are sensitive to mechanical properties of concrete, these solicitations are strongly influenced by the mechanical and geometrical characteristics of the soil mass. However, it should be noted that the influence of Eb is denoted in the center of the plate whereas the Es feels almost in the same manner over the entire extent of the plate. This study also shows that for the same load cases, the values of the torsion moment and shear stress are not significant those of bending moments and normal stresses, respectively.展开更多
In this research, we study the relationship between mental workload and facial temperature of aircraft participants during a simulated takeoff flight. We conducted experiments to comprehend the correlation between wor...In this research, we study the relationship between mental workload and facial temperature of aircraft participants during a simulated takeoff flight. We conducted experiments to comprehend the correlation between work and facial temperature within the flight simulator. The experiment involved a group of 10 participants who played the role of pilots in a simulated A-320 flight. Six different flying scenarios were designed to simulate normal and emergency situations on airplane takeoff that would occur in different levels of mental workload for the participants. The measurements were workload assessment, face temperatures, and heart rate monitoring. Throughout the experiments, we collected a total of 120 instances of takeoffs, together with over 10 hours of time-series data including heart rate, workload, and face thermal images and temperatures. Comparative analysis of EEG data and thermal image types, revealed intriguing findings. The results indicate a notable inverse relationship between workload and facial muscle temperatures, as well as facial landmark points. The results of this study contribute to a deeper understanding of the physiological effects of workload, as well as practical implications for aviation safety and performance.展开更多
The lack of treatment for poliomyelitis doing that only means of preventing is immunization with live oral polio vaccine (OPV) or/and inactivated polio vaccine (IPV). Poliomyelitis is a very contagious viral infection...The lack of treatment for poliomyelitis doing that only means of preventing is immunization with live oral polio vaccine (OPV) or/and inactivated polio vaccine (IPV). Poliomyelitis is a very contagious viral infection caused by poliovirus. Children are principally attacked. In this paper, we assess the impact of vaccination in the control of spread of poliomyelitis via a deterministic SVEIR (Susceptible-Vaccinated-Latent-Infectious-Removed) model of infectious disease transmission, where vaccinated individuals are also susceptible, although to a lesser degree. Using Lyapunov-Lasalle methods, we prove the global asymptotic stability of the unique endemic equilibrium whenever ?. Numerical simulations, using poliomyelitis data from Cameroon, are conducted to approve analytic results and to show the importance of vaccinate coverage in the control of disease spread.展开更多
A simulation was carried out on an unsteady flow of a viscous, incompressible and electrically conducting fluid past an infinite vertical porous plate. A generic computer program using the Galerkin finite element meth...A simulation was carried out on an unsteady flow of a viscous, incompressible and electrically conducting fluid past an infinite vertical porous plate. A generic computer program using the Galerkin finite element method is employed to solve the coupled non-linear differential equations for velocity and temperature fields. The diffusion equation, the energy equation, the momentum equations and other relevant parameters are transformed into interpretable postfix codes. Numerical calculations are carried out on the flow fields both in the presence of cooling and heating of the plate by free convection currents. The effects of the dimensionless parameters, namely, the Prandtl number, the Eckert number, the modified Grashof number, the Schmidt number and the time on the temperature and velocity distributions are discussed.展开更多
文摘A new class of reflected backward stochastic differential equations (RBSDEs) driven by Teugels martingales associated with Lévy process and Countable Brownian Motions are investigated. Via approximation, the existence and uniqueness of solution to this kind of RBSDEs are obtained.
文摘The purpose of this contribution is to lay down a preparatory groundwork for an ontology of ecosystem services in the setting of agroecosystems viewed as social-ecological systems. This ontology aims at defining a set of representational primitives with which to model agroecosystems, through the prism of ecosystem service flows to and from agriculture. It helps delineate between biophysical structures, processes, functions, and ecosystem services. On the human side of agroecosystems, the ontology includes a conceptualization of the behaviors that govern the management of ecosystem services at different levels. It strengthens the existing analytic basis of multidisciplinary research on ecosystem services in agroecosystems by prompting modelers to stick to a homogeneous dynamic-system decomposition of the target agroecosystem. Most importantly, it provides the conceptual link between biophysical research on ecosystem services and equally important considerations on cognitive and social aspects involved in agricultural and landscape-level decisions that aim at implementing agroecological principles.
文摘This work concerns a dynamic modeling and a numerical simulation of the operation of an adsorption solar refrigeration system using the zeolite-water couple. For this, a mathematical model representing the evolution of heat and mass transfer at each component of the solar adsorption refrigerator has been developed. We have adopted the Dubinin-Astakhov model for the adsorption kinetics of the zeolite/water pair. This model allows to describe the phenomenon of adsorption and to calculate the rate of adsorbate (water) in the zeolite (adsorbent) as a function of the temperature and the pressure. The equations governing the operation of the solar adsorption refrigerator, deduced from the thermal and mass balances established at the collector adsorber, condenser and evaporator components, were solved by an implicit finite difference scheme and Gauss Seidel’s iterative method. We have validated the model established by applying it to the model of Allouhi et al. 2014. We analyzed the influence of the adsorbate/adsorbent couples, the solar flux, the ambient temperature on the adsorption and desorption process. The temperature profiles obtained representing the temperature evolution of the glass, the absorbent plate, the zeolite-water mixture, the condenser, the evaporator, as well as the pressure and the adsorbed mass allowed us to evaluate the performance of the solar adsorption refrigerator. SCOP is higher the higher the solar flux captured by the collector-adsorber.
文摘This work studies the influence of mechanical and geometrical characteristics of the concrete and the soil on the stresses in a mat foundation. In this study, the soil-structure interaction is modeled by two parameters, the modulus of subgrade vertical reaction (k) and the modulus of subgrade horizontal reaction (2T). These two parameters are dependent on the geometrical and mechanical characteristics of the system. Results of this study show a sensitivity of solicitations to variations of geometrical and mechanical characteristics of the model. Although solicitations in the plate are sensitive to mechanical properties of concrete, these solicitations are strongly influenced by the mechanical and geometrical characteristics of the soil mass. However, it should be noted that the influence of Eb is denoted in the center of the plate whereas the Es feels almost in the same manner over the entire extent of the plate. This study also shows that for the same load cases, the values of the torsion moment and shear stress are not significant those of bending moments and normal stresses, respectively.
文摘In this research, we study the relationship between mental workload and facial temperature of aircraft participants during a simulated takeoff flight. We conducted experiments to comprehend the correlation between work and facial temperature within the flight simulator. The experiment involved a group of 10 participants who played the role of pilots in a simulated A-320 flight. Six different flying scenarios were designed to simulate normal and emergency situations on airplane takeoff that would occur in different levels of mental workload for the participants. The measurements were workload assessment, face temperatures, and heart rate monitoring. Throughout the experiments, we collected a total of 120 instances of takeoffs, together with over 10 hours of time-series data including heart rate, workload, and face thermal images and temperatures. Comparative analysis of EEG data and thermal image types, revealed intriguing findings. The results indicate a notable inverse relationship between workload and facial muscle temperatures, as well as facial landmark points. The results of this study contribute to a deeper understanding of the physiological effects of workload, as well as practical implications for aviation safety and performance.
文摘The lack of treatment for poliomyelitis doing that only means of preventing is immunization with live oral polio vaccine (OPV) or/and inactivated polio vaccine (IPV). Poliomyelitis is a very contagious viral infection caused by poliovirus. Children are principally attacked. In this paper, we assess the impact of vaccination in the control of spread of poliomyelitis via a deterministic SVEIR (Susceptible-Vaccinated-Latent-Infectious-Removed) model of infectious disease transmission, where vaccinated individuals are also susceptible, although to a lesser degree. Using Lyapunov-Lasalle methods, we prove the global asymptotic stability of the unique endemic equilibrium whenever ?. Numerical simulations, using poliomyelitis data from Cameroon, are conducted to approve analytic results and to show the importance of vaccinate coverage in the control of disease spread.
文摘A simulation was carried out on an unsteady flow of a viscous, incompressible and electrically conducting fluid past an infinite vertical porous plate. A generic computer program using the Galerkin finite element method is employed to solve the coupled non-linear differential equations for velocity and temperature fields. The diffusion equation, the energy equation, the momentum equations and other relevant parameters are transformed into interpretable postfix codes. Numerical calculations are carried out on the flow fields both in the presence of cooling and heating of the plate by free convection currents. The effects of the dimensionless parameters, namely, the Prandtl number, the Eckert number, the modified Grashof number, the Schmidt number and the time on the temperature and velocity distributions are discussed.
