The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption th...The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.展开更多
In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and...In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.展开更多
The study of thermal comfort in the built environment is of great relevance since it stimulates the development of more sustainable buildings suited to the local climate and able to meet the human need for well-being....The study of thermal comfort in the built environment is of great relevance since it stimulates the development of more sustainable buildings suited to the local climate and able to meet the human need for well-being.The objective of this research was to develop,construct and test a passive heating system adaptable to existing buildings,reducing the need for major interventions and increasing thermal comfort in the indoor environment.The adopted methodological approach was a case study in a single-family residence located in the Brazilian city of Petrópolis,a mountainous region with a humid subtropical climate and a rigorous winter.The proposed passive heating system is totally isolated,thus mitigating air infiltration and promoting increase of temperature in the internal environment through the absorption of solar energy and greenhouse effect.This kind of solution is especially interesting for residents of this region,since most of the city buildings are not adequately prepared to handle low temperatures.Thus,given local climatic conditions,residents need to spend a lot of money on the acquisition and operation of electric or gas heating systems.The results indicated that the developed system,in fact,increased the temperature of the studied room when compared to an adjacent room,which did not receive the device.The findings of this paper,therefore,provide a valuable reference for experts and practitioners in the selection of heating systems to be used in cold regions,and proved that passive systems can provide thermal comfort at the same time that optimize the interaction of the building with the local ecosystem.展开更多
For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digit...For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digital passive intermodulation（PIM） suppression approaches can be easily reconfigured and therefore are highly attractive for future satellite communication systems.A simplified model of nonlinear distortion from passive microwave devices is established in consideration of the memory effect.The multiple high-order PIM products falling into the receiving band can be described as a bilinear predictor function.A suppression algorithm based on a bilinear polynomial decorrelated adaptive filter is proposed for baseband digital signal processing.In consideration of the time-varying characteristics of passive intermodulation,this algorithm can achieve the rapidness of online interference estimation and low complexity with less consumption of resources.Numerical simulation results show that the algorithm can effectively compensate the passive intermodulation interference,and achieve a high signal-to-interference ratio gain.展开更多
In the near future, active safety systems will take more control over the vehicle driving, even up to introducing fully autonomous vehicles. Nowadays, it is expected that the active safety systems will aid avoiding co...In the near future, active safety systems will take more control over the vehicle driving, even up to introducing fully autonomous vehicles. Nowadays, it is expected that the active safety systems will aid avoiding collisions much more efficiently than human drivers. These systems can protect not only the passengers, but also other road users. To mitigate collision, certain maneuvers （e.g., sudden braking, lane change, etc.） need to be done in a reasonably quick time. However, this may lead to low-g energy pulses. The latter fact, may cause unexpected and, in some cases, unwanted occupant body motion resulting even in OOP （out of position） postures. New patterns of occupant reactions in such cases are, to some extent, confirmed experimentally [1-3]. This paper evaluates the limits of standard ATDs （anthropometric test devices） and chosen human models in well established maneuver scenarios. Obtained results are compared with experimental data available in the literature. Drawbacks identify new challenges for the near future simulation based safety engineering. One scenario with combined conditions of emergency braking during lane change has been used as an example of OOP posture after maneuver.展开更多
In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a p...In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a passive transmission and distribution(T&D)grid,by adopting the port-Hamiltonian(pH)systems theory and the fundamental circuit theory.The models of generic T&D lines are developed and then the model of a generic T&D grid is established.With the proposed control framework,the controlled converters are proven to be passive and Input-to-State Stable(ISS).The compact mathematical model is scalable and can be applied to power systems with multiple power electronic converters with generic passive controllers,passive local loads,and different types of passive T&D lines connected in a meshed configuration without self-loops,so it is very generic.Moreover,the resulting power system is proven to be ISS as well.The analysis is carried out without assumptions on constant frequency/voltage,constant loads,and/or lossless networks,except the need of passivity for all parts involved,and without using the Clarke/Park transformations or the graph theory.To simplify the presentation,three-phase balanced systems are adopted but the results can be easily adapted for single-phase or unbalanced three-phase systems.展开更多
Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are w...Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new,dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall,and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).展开更多
Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for build...Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for buildings are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).展开更多
There are prototypes of social housing massively built in contrasting climatic conditions,generating thermal comfort needs that are difficult to satisfy by the users themselves.Variation of indoor air volume in living...There are prototypes of social housing massively built in contrasting climatic conditions,generating thermal comfort needs that are difficult to satisfy by the users themselves.Variation of indoor air volume in living spaces where the use of air conditioning and natural ventilation strategies provides elements to improve thermal comfort conditions.This research shows the thermal performance located in a representative social housing according to Mexico’s National Housing Commission.Operative temperature results from a benchmark case were compared to six Virtual Evaluation Models,using the Dynamic Thermal Simulation tool Design Builder®from the perspective of probability.The main objective was to determine the minimum use of active systems with different indoor air volumes and improve comfort conditions to promote sustainable living in social housing.The analysis was conducted under an adaptive comfort range according to three different climate conditions in Mexico adopting a Numerical Theoretical Method.The main findings can be divided into two parts:a)the impact of the indoor air volume on thermal performance was evidenced in a proportion of time in three representative climates of the central region of Mexico,and b)no relationship was found between indoor air volume and thermal comfort in sub-humid cold climate;in sub-humid temperate climate,the same number of comfort hours was found in two different models,and in sub-humid warm climate,an inversely proportional relationship was found between indoor air volume and the comfort hours.This findings implies a greater knowledge relative to what we know about sub-humid cold,temperate and warm climates.展开更多
文摘The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.
基金supported by Natural Sciences and Engineering Research Council of Canada (NSERC) Research Fellowship,Canada Research Chairs Program and University of Ottawa Research Chair Program
文摘In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.
文摘The study of thermal comfort in the built environment is of great relevance since it stimulates the development of more sustainable buildings suited to the local climate and able to meet the human need for well-being.The objective of this research was to develop,construct and test a passive heating system adaptable to existing buildings,reducing the need for major interventions and increasing thermal comfort in the indoor environment.The adopted methodological approach was a case study in a single-family residence located in the Brazilian city of Petrópolis,a mountainous region with a humid subtropical climate and a rigorous winter.The proposed passive heating system is totally isolated,thus mitigating air infiltration and promoting increase of temperature in the internal environment through the absorption of solar energy and greenhouse effect.This kind of solution is especially interesting for residents of this region,since most of the city buildings are not adequately prepared to handle low temperatures.Thus,given local climatic conditions,residents need to spend a lot of money on the acquisition and operation of electric or gas heating systems.The results indicated that the developed system,in fact,increased the temperature of the studied room when compared to an adjacent room,which did not receive the device.The findings of this paper,therefore,provide a valuable reference for experts and practitioners in the selection of heating systems to be used in cold regions,and proved that passive systems can provide thermal comfort at the same time that optimize the interaction of the building with the local ecosystem.
基金supported by the National Natural SciencFoundation of China(Nos.U1636125,61601027)
文摘For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digital passive intermodulation（PIM） suppression approaches can be easily reconfigured and therefore are highly attractive for future satellite communication systems.A simplified model of nonlinear distortion from passive microwave devices is established in consideration of the memory effect.The multiple high-order PIM products falling into the receiving band can be described as a bilinear predictor function.A suppression algorithm based on a bilinear polynomial decorrelated adaptive filter is proposed for baseband digital signal processing.In consideration of the time-varying characteristics of passive intermodulation,this algorithm can achieve the rapidness of online interference estimation and low complexity with less consumption of resources.Numerical simulation results show that the algorithm can effectively compensate the passive intermodulation interference,and achieve a high signal-to-interference ratio gain.
文摘In the near future, active safety systems will take more control over the vehicle driving, even up to introducing fully autonomous vehicles. Nowadays, it is expected that the active safety systems will aid avoiding collisions much more efficiently than human drivers. These systems can protect not only the passengers, but also other road users. To mitigate collision, certain maneuvers （e.g., sudden braking, lane change, etc.） need to be done in a reasonably quick time. However, this may lead to low-g energy pulses. The latter fact, may cause unexpected and, in some cases, unwanted occupant body motion resulting even in OOP （out of position） postures. New patterns of occupant reactions in such cases are, to some extent, confirmed experimentally [1-3]. This paper evaluates the limits of standard ATDs （anthropometric test devices） and chosen human models in well established maneuver scenarios. Obtained results are compared with experimental data available in the literature. Drawbacks identify new challenges for the near future simulation based safety engineering. One scenario with combined conditions of emergency braking during lane change has been used as an example of OOP posture after maneuver.
基金supported by NSF,USA,under award#1810105 and Foundation for Research Support of the State of Rio Grande do Sul(FAPERGS),BR,under grant number 21/2551-0002158-6,CfP PqG.2021。
文摘In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a passive transmission and distribution(T&D)grid,by adopting the port-Hamiltonian(pH)systems theory and the fundamental circuit theory.The models of generic T&D lines are developed and then the model of a generic T&D grid is established.With the proposed control framework,the controlled converters are proven to be passive and Input-to-State Stable(ISS).The compact mathematical model is scalable and can be applied to power systems with multiple power electronic converters with generic passive controllers,passive local loads,and different types of passive T&D lines connected in a meshed configuration without self-loops,so it is very generic.Moreover,the resulting power system is proven to be ISS as well.The analysis is carried out without assumptions on constant frequency/voltage,constant loads,and/or lossless networks,except the need of passivity for all parts involved,and without using the Clarke/Park transformations or the graph theory.To simplify the presentation,three-phase balanced systems are adopted but the results can be easily adapted for single-phase or unbalanced three-phase systems.
文摘Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new,dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall,and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).
文摘Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for buildings are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).
基金This paper was made supported by grants from Mexico’s National Council of Science and Technology(CONACyT,by its Spanish acronym).
文摘There are prototypes of social housing massively built in contrasting climatic conditions,generating thermal comfort needs that are difficult to satisfy by the users themselves.Variation of indoor air volume in living spaces where the use of air conditioning and natural ventilation strategies provides elements to improve thermal comfort conditions.This research shows the thermal performance located in a representative social housing according to Mexico’s National Housing Commission.Operative temperature results from a benchmark case were compared to six Virtual Evaluation Models,using the Dynamic Thermal Simulation tool Design Builder®from the perspective of probability.The main objective was to determine the minimum use of active systems with different indoor air volumes and improve comfort conditions to promote sustainable living in social housing.The analysis was conducted under an adaptive comfort range according to three different climate conditions in Mexico adopting a Numerical Theoretical Method.The main findings can be divided into two parts:a)the impact of the indoor air volume on thermal performance was evidenced in a proportion of time in three representative climates of the central region of Mexico,and b)no relationship was found between indoor air volume and thermal comfort in sub-humid cold climate;in sub-humid temperate climate,the same number of comfort hours was found in two different models,and in sub-humid warm climate,an inversely proportional relationship was found between indoor air volume and the comfort hours.This findings implies a greater knowledge relative to what we know about sub-humid cold,temperate and warm climates.
