African countries need customized efforts to fight climate change SOME 350 km northeast of Nairobi, Kenya,almost 300,000 Kapedo villagers in Turkana County came close to starvation this year after their cattle died in...African countries need customized efforts to fight climate change SOME 350 km northeast of Nairobi, Kenya,almost 300,000 Kapedo villagers in Turkana County came close to starvation this year after their cattle died in what is one of the country’s most drought affected districts.This number, according to the World Food Program (WFP),constitutes 10 percent of the entire Horn of Africa population affected by famine. The WFP said this was the region’s worst drought in 60 years. Kenya depends entirely on rain-展开更多
THERE'S always good news for farmers and therural community at the beginning of the year. This year is of no exception. On February 5.2017, the Central Committee of the Communist Party of China and the State Council ...THERE'S always good news for farmers and therural community at the beginning of the year. This year is of no exception. On February 5.2017, the Central Committee of the Communist Party of China and the State Council jointly released this year's "No.1 Central Document." entitled Opinions on Deepening Supply-Side Structural Reform in Agriculture and Accelerating the Cul tivation of New Growth Engines for Agricultural Reform and Rural Areas, This is the 14th straight year that the "No.1 Central Document" targets agricultural and rural development and farmers.展开更多
Published in November 2013, the book More Time for China, More Time forDream swept the book market and was reprinted three times in only six weeks. WangWen, one of the four writers shared the ideas behind the book and...Published in November 2013, the book More Time for China, More Time forDream swept the book market and was reprinted three times in only six weeks. WangWen, one of the four writers shared the ideas behind the book and how it came into being.展开更多
A portfolio of new energy technologies has emerged in the first decade of the 21st Century, and many of them could be used for re-structuring the energy sector towards Sustainable Development. A key subject in this qu...A portfolio of new energy technologies has emerged in the first decade of the 21st Century, and many of them could be used for re-structuring the energy sector towards Sustainable Development. A key subject in this quest is the future of automobile, with possibilities on powering ranging from biofuels to Hydrogen Cars (HC), to Electric Vehicles (EV). In turn, the latter is closely connected with the need to deploy Renewable Energies (RE) for electricity generation. Within such new situation, countries and governments are aware that there are new tools for fighting Global Warming (GW), and new policies could be established for winning this battle against CO2. All these initiatives will affect the future of energy corporations, notably hydrocarbon companies;and it should be noted that it will be difficult for the companies to define long-term strategies if energy policies convey upheavals, sudden changes in promoting alternatives and interruptions on activities. Hence, it is very important to adopt energy policies allowing a smooth evolution of the companies’ activities to the new energy model. After analyzing the alternatives with a forecasting-backcasting methodology, an “eclectic approach” is proposed, with the Plug-in Hybrid car with Flexible Fuel (PiHFF) as the central paradigm in the coming promoting policies.展开更多
A fast self-adapting high-order sliding mode(FSHOSM)controller is designed for a class of nonlinear systems with unknown uncertainties.As for uncertainty-free nonlinear system,a new switching condition is introduced i...A fast self-adapting high-order sliding mode(FSHOSM)controller is designed for a class of nonlinear systems with unknown uncertainties.As for uncertainty-free nonlinear system,a new switching condition is introduced into the standard geometric homogeneity.Different from the existing geometric homogeneity method,both state variables and their derivatives are considered to bring a reasonable effective switching condition.As a result,a faster convergence rate of state variables is achieved.Furthermore,based on the integral sliding mode(ISM)and above geometric homogeneity,a self-adapting high-order sliding mode(HOSM)control law is proposed for a class of nonlinear systems with uncertainties.The resulting controller allows the closed-loop system to conduct with the expected properties of strong robustness and fast convergence.Stable analysis of the nonlinear system is also proved based on the Lyapunov approach.The effectiveness of the resulting controller is verified by several simulation results.展开更多
A contextual review of models for chronic care was done to develop a context-adapted chronic care model-based service delivery model for chronic conditions including diabetes.The Philippines was used as the setting of...A contextual review of models for chronic care was done to develop a context-adapted chronic care model-based service delivery model for chronic conditions including diabetes.The Philippines was used as the setting of a low-to-middle-income country.A context-based narrative review of existing models for chronic care was conducted.A situational analysis was done at thegrassroots level,involving the leaders and members of the community,the patients,the local health system and the healthcare providers.A second analysis making use of certain organizational theories was done to explore on improving feasibility and acceptability of organizing care for chronic conditions.The analyses indicated that care for chronic conditions may be introduced,considering the needs of people with diabetes in particular and the community in general as recipients of care,and the issues and factors that may affect the healthcare workers and the health system as providers of this care.The context-adapted chronic care model-based service delivery model was constructed accordingly.Key features are:incorporation of chronic care in the health system's services; assimilation of chronic care delivery with the other responsibilities of the healthcare workers but with redistribution of certain tasks; and ensuring that the recipients of care experience the whole spectrum of basic chronic care that includes education and promotion in the general population,risk identification,screening,counseling including self-care development,and clinical management of the chronic condition and any co-morbidities,regardless of level of control of the condition.This way,low-to-middle income countries can introduce and improve care for chronic conditions without entailing much additional demand on their limited resources.展开更多
It is increasingly recognised that collecting patient reported outcome measures(PROMs)data is an important part of healthcare and should be considered alongside traditional clinical assessments.As part of a more holis...It is increasingly recognised that collecting patient reported outcome measures(PROMs)data is an important part of healthcare and should be considered alongside traditional clinical assessments.As part of a more holistic view of healthcare provision,there has been an increased drive to implement PROM collection as part of routine clinical care in hepatology.This drive has resulted in an increase in the number of PROMs currently developed to be used in various liver conditions.However,the development and validation of a new PROM is time-consuming and costly.Therefore,before deciding to develop a new PROM,researchers should consider identifying existing PROMs to assess their appropriateness and,if necessary,make adaptations to existing PROMs to ensure their rigour when used with the target population.Little is written in the literature on how to identify and adapt the existing PROMs in hepatology.This article aims to provide a summary of the current literature and guidance regarding identifying and adapting existing PROMs in clinical practice.展开更多
With the expansion of mountainous cities,many gully areas have been included in the scope of urban construction land.These gully areas will restrict urban construction because of sensitivity and instability caused by ...With the expansion of mountainous cities,many gully areas have been included in the scope of urban construction land.These gully areas will restrict urban construction because of sensitivity and instability caused by the unique ecological processes.This paper attempts to explore a planning and design strategy that combines ecological processes to reduce the risk of urban construction in gully areas.According to the ecological characteristics of gully areas,especially its suitability for urban construction,gully areas can be divided into three categories in the mountainous city:prevention and controlling gully—focusing on gully drainage;conservation gully—focusing on the construction of green space;utilization type gully—focusing on the development of gully towns.The utilization type gully can be used as urban construction land.For utilization type gullies,horizontal and vertical segmented planning strategies can adopt their respective ecological processes by land utilization,landscape construction,spatial layout and traffic organization matching the time-space natural process to form harmony human settlements.展开更多
The efforts in this study are made to demonstrate how an EFL teacher should develop and adapt the ESP reading materials to meet their English majors’needs and the social contexts where the learners are going to work....The efforts in this study are made to demonstrate how an EFL teacher should develop and adapt the ESP reading materials to meet their English majors’needs and the social contexts where the learners are going to work.Based on a study of literature about material development and a case analysis of the teaching situation and students’profile,five criteria are proposed for selecting and adapting materials suitable for 3rd-year Hainan University English majors,and then an evaluation of the reading texts of the course book English for Tourism and Hospitality is made with these yardsticks.In view of the discussion and analysis,suggestions about ESP reading material development are put forth.展开更多
Platooning represents one of the key features that connected automated vehicles may possess as it allows multiple automated vehicles to be maneuvered cooperatively with small headways on roads. However, a critical cha...Platooning represents one of the key features that connected automated vehicles may possess as it allows multiple automated vehicles to be maneuvered cooperatively with small headways on roads. However, a critical challenge in accomplishing automated vehicle platoons is to deal with the effects of intermittent and sporadic vehicle-to-vehicle data transmissions caused by limited wireless communication resources. This paper addresses the co-design problem of dynamic event-triggered communication scheduling and cooperative adaptive cruise control for a convoy of automated vehicles with diverse spacing policies. The central aim is to achieve automated vehicle platooning under various gap references with desired platoon stability and spacing performance requirements, while simultaneously improving communication efficiency. Toward this aim, a dynamic event-triggered scheduling mechanism is developed such that the intervehicle data transmissions are scheduled dynamically and efficiently over time. Then, a tractable co-design criterion on the existence of both the admissible event-driven cooperative adaptive cruise control law and the desired scheduling mechanism is derived. Finally, comparative simulation results are presented to substantiate the effectiveness and merits of the obtained results.展开更多
Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and ...Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.展开更多
More and more accounts or devices are shared by multiple users in video applications,which makes it difficult to provide recommendation service.Existing recommendation schemes overlook multiuser sharing scenarios,and ...More and more accounts or devices are shared by multiple users in video applications,which makes it difficult to provide recommendation service.Existing recommendation schemes overlook multiuser sharing scenarios,and they cannot make effective use of the mixed information generated by multi-user when exploring users’potential interests.To solve these problems,this paper proposes an adaptive program recommendation system for multi-user sharing environment.Specifically,we first design an offline periodic identification module by building multi-user features and periodically predicting target user in future sessions,which can separate the profile of target user from mixed log records.Subsequently,an online recommendation module with adaptive timevarying exploration strategy is constructed by jointly using personal information and multi-user social information provided by identification module.On one hand,to learn the dynamic changes in user-interest,a time-varying linear upper confidence bound(LinUCB)based on personal information is designed.On the other hand,to reduce the risk of exploration,a timeinvariant LinUCB based on separated multi-user social information from one account/device is proposed to compute the quality scores of programs for each user,which is integrated into the time-varying LinUCB by cross-weighting strategy.Finally,experimental results validate the efficiency of the proposed scheme.展开更多
The 2.5 m wide-field and high-resolution solar telescope(WeHoST)is currently under developing for solar observations.WeHoST aims to achieve high-resolution observations over a super-wide field of view(FOV)of5′×5...The 2.5 m wide-field and high-resolution solar telescope(WeHoST)is currently under developing for solar observations.WeHoST aims to achieve high-resolution observations over a super-wide field of view(FOV)of5′×5′,and a desired resolution of 0.3″.To meet the scientific requirements of WeHoST,the ground-layer adaptive optics(GLAO)with a specially designed wave front sensing system is as the primary consideration.We introduce the GLAO configuration,particularly the wave front sensing scheme.Utilizing analytic method,we simulate the performance of both classical AO and GLAO systems,optimize the wave front sensing system,and evaluate GLAO performance in terms of PSF uniformity and correction improvement across whole FOV.The results indicate that,the classical AO will achieve diffraction-limited resolution;the suggested GLAO configuration will uniformly improve the seeing across the full 5′×5′FOV,reducing the FWHM across the axis FOV to less than0.3″(λ≥705 nm,r0≥11 cm),which is more than two times improvement.The specially designed wave front sensor schedule offers new potential for WeHoST’s GLAO,particularly the multi-FOV GLAO and the flexibility to select the detected area.These capabilities will significantly enhance the scientific output of the telescope.展开更多
Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise...Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise has long been an area of active research.Studies of the vertebrate locomotor system’s adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during exercise.In this brief review,we highlight recent results and insights from the field with a focus on the following mechanisms:(a)alterations in neuronal excitability during acute exercise;(b)alterations in neuronal excitability after chronic exercise;(c)exercise-induced changes in neuronal membrane properties via modulation of ion channel activity;(d)exercise-enhanced dendritic plasticity;and(e)exercise-induced alterations in neuronal gene expression and protein synthesis.Our hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise.展开更多
Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the O...Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the OsNCED2 gene between upland and irrigated populations.A nonsynonymous mutation(C to T,from irrigated to upland rice)may have led to functional variation fixed by artificial selection,but the exact biological function in dryland adaptation is unclear.In this study,transgenic and association analysis indicated that the domesticated fixed mutation caused functional variation in OsNCED2,increasing ABA levels,root development,and drought tolerance in upland rice under dryland conditions.OsNCED2-overexpressing rice showed increased reactive oxygen species-scavenging abilities and transcription levels of many genes functioning in stress response and development that may regulate root development and drought tolerance.OsNCED2^(T)-NILs showed a denser root system and drought resistance,promoting the yield of rice under dryland conditions.OsNCED2^(T)may confer dryland adaptation in upland rice and may find use in breeding dryland-adapted,water-saving rice.展开更多
This paper investigates the adaptive trajectory tracking control problem and the unknown parameter identification problem of a class of rotor-missiles with parametric system uncertainties.First,considering the uncerta...This paper investigates the adaptive trajectory tracking control problem and the unknown parameter identification problem of a class of rotor-missiles with parametric system uncertainties.First,considering the uncertainty of structural and aerodynamic parameters,the six-degree-of-freedom(6Do F) nonlinear equations describing the position and attitude dynamics of the rotor-missile are established,respectively,in the inertial and body-fixed reference frames.Next,a hierarchical adaptive trajectory tracking controller that can guarantee closed-loop stability is proposed according to the cascade characteristics of the 6Do F dynamics.Then,a memory-augmented update rule of unknown parameters is proposed by integrating all historical data of the regression matrix.As long as the finitely excited condition is satisfied,the precise identification of unknown parameters can be achieved.Finally,the validity of the proposed trajectory tracking controller and the parameter identification method is proved through Lyapunov stability theory and numerical simulations.展开更多
Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate trackin...Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.展开更多
Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present ...Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present study,we discovered that the Nile tilapia(Oreochromis niloticus)encodes key components of the LAT signalosome,namely,LAT,ITK,GRB2,VAV1,SLP-76,GADS,and PLC-γ1.These components are evolutionarily conserved,and CD3εmAb-induced T-cell activation markedly increased their expression.Additionally,at least ITK,GRB2,and VAV1 were found to interact with LAT for signalosome formation.Downstream of the first signal,the NF-κB,MAPK/ERK,and PI3K-AKT pathways were activated upon CD3εmAb stimulation.Furthermore,treatment of lymphocytes with CD28 mAbs triggered the AKT-mTORC1 pathway downstream of the co-stimulatory signal.Combined CD3εand CD28 mAb stimulation enhanced ERK1/2 and S6 phosphorylation and elevated NFAT1,c-Fos,IL-2,CD122,and CD44 expression,thereby signifying T-cell activation.Moreover,rather than relying on the first or co-stimulatory signal alone,both signals were required for T-cell proliferation.Full T-cell activation was accompanied by marked apoptosis and cytotoxic responses.These findings suggest that tilapia relies on dual signaling to maintain an optimal T-cell response,providing a novel perspective for understanding the evolution of the adaptive immune system.展开更多
文摘African countries need customized efforts to fight climate change SOME 350 km northeast of Nairobi, Kenya,almost 300,000 Kapedo villagers in Turkana County came close to starvation this year after their cattle died in what is one of the country’s most drought affected districts.This number, according to the World Food Program (WFP),constitutes 10 percent of the entire Horn of Africa population affected by famine. The WFP said this was the region’s worst drought in 60 years. Kenya depends entirely on rain-
文摘THERE'S always good news for farmers and therural community at the beginning of the year. This year is of no exception. On February 5.2017, the Central Committee of the Communist Party of China and the State Council jointly released this year's "No.1 Central Document." entitled Opinions on Deepening Supply-Side Structural Reform in Agriculture and Accelerating the Cul tivation of New Growth Engines for Agricultural Reform and Rural Areas, This is the 14th straight year that the "No.1 Central Document" targets agricultural and rural development and farmers.
文摘Published in November 2013, the book More Time for China, More Time forDream swept the book market and was reprinted three times in only six weeks. WangWen, one of the four writers shared the ideas behind the book and how it came into being.
文摘A portfolio of new energy technologies has emerged in the first decade of the 21st Century, and many of them could be used for re-structuring the energy sector towards Sustainable Development. A key subject in this quest is the future of automobile, with possibilities on powering ranging from biofuels to Hydrogen Cars (HC), to Electric Vehicles (EV). In turn, the latter is closely connected with the need to deploy Renewable Energies (RE) for electricity generation. Within such new situation, countries and governments are aware that there are new tools for fighting Global Warming (GW), and new policies could be established for winning this battle against CO2. All these initiatives will affect the future of energy corporations, notably hydrocarbon companies;and it should be noted that it will be difficult for the companies to define long-term strategies if energy policies convey upheavals, sudden changes in promoting alternatives and interruptions on activities. Hence, it is very important to adopt energy policies allowing a smooth evolution of the companies’ activities to the new energy model. After analyzing the alternatives with a forecasting-backcasting methodology, an “eclectic approach” is proposed, with the Plug-in Hybrid car with Flexible Fuel (PiHFF) as the central paradigm in the coming promoting policies.
基金supported by the National Natural Science Foundation of China(61433003,60904003,11602019).
文摘A fast self-adapting high-order sliding mode(FSHOSM)controller is designed for a class of nonlinear systems with unknown uncertainties.As for uncertainty-free nonlinear system,a new switching condition is introduced into the standard geometric homogeneity.Different from the existing geometric homogeneity method,both state variables and their derivatives are considered to bring a reasonable effective switching condition.As a result,a faster convergence rate of state variables is achieved.Furthermore,based on the integral sliding mode(ISM)and above geometric homogeneity,a self-adapting high-order sliding mode(HOSM)control law is proposed for a class of nonlinear systems with uncertainties.The resulting controller allows the closed-loop system to conduct with the expected properties of strong robustness and fast convergence.Stable analysis of the nonlinear system is also proved based on the Lyapunov approach.The effectiveness of the resulting controller is verified by several simulation results.
基金Supported by The Belgian Directorate for Development Cooperation through the Institute of Tropical Medicine,Antwerp
文摘A contextual review of models for chronic care was done to develop a context-adapted chronic care model-based service delivery model for chronic conditions including diabetes.The Philippines was used as the setting of a low-to-middle-income country.A context-based narrative review of existing models for chronic care was conducted.A situational analysis was done at thegrassroots level,involving the leaders and members of the community,the patients,the local health system and the healthcare providers.A second analysis making use of certain organizational theories was done to explore on improving feasibility and acceptability of organizing care for chronic conditions.The analyses indicated that care for chronic conditions may be introduced,considering the needs of people with diabetes in particular and the community in general as recipients of care,and the issues and factors that may affect the healthcare workers and the health system as providers of this care.The context-adapted chronic care model-based service delivery model was constructed accordingly.Key features are:incorporation of chronic care in the health system's services; assimilation of chronic care delivery with the other responsibilities of the healthcare workers but with redistribution of certain tasks; and ensuring that the recipients of care experience the whole spectrum of basic chronic care that includes education and promotion in the general population,risk identification,screening,counseling including self-care development,and clinical management of the chronic condition and any co-morbidities,regardless of level of control of the condition.This way,low-to-middle income countries can introduce and improve care for chronic conditions without entailing much additional demand on their limited resources.
文摘It is increasingly recognised that collecting patient reported outcome measures(PROMs)data is an important part of healthcare and should be considered alongside traditional clinical assessments.As part of a more holistic view of healthcare provision,there has been an increased drive to implement PROM collection as part of routine clinical care in hepatology.This drive has resulted in an increase in the number of PROMs currently developed to be used in various liver conditions.However,the development and validation of a new PROM is time-consuming and costly.Therefore,before deciding to develop a new PROM,researchers should consider identifying existing PROMs to assess their appropriateness and,if necessary,make adaptations to existing PROMs to ensure their rigour when used with the target population.Little is written in the literature on how to identify and adapt the existing PROMs in hepatology.This article aims to provide a summary of the current literature and guidance regarding identifying and adapting existing PROMs in clinical practice.
基金supported by National Key R&D Program of China“Optimization Technology for Urban New District Planning and Design(Grant No.2018YFC0704600)”
文摘With the expansion of mountainous cities,many gully areas have been included in the scope of urban construction land.These gully areas will restrict urban construction because of sensitivity and instability caused by the unique ecological processes.This paper attempts to explore a planning and design strategy that combines ecological processes to reduce the risk of urban construction in gully areas.According to the ecological characteristics of gully areas,especially its suitability for urban construction,gully areas can be divided into three categories in the mountainous city:prevention and controlling gully—focusing on gully drainage;conservation gully—focusing on the construction of green space;utilization type gully—focusing on the development of gully towns.The utilization type gully can be used as urban construction land.For utilization type gullies,horizontal and vertical segmented planning strategies can adopt their respective ecological processes by land utilization,landscape construction,spatial layout and traffic organization matching the time-space natural process to form harmony human settlements.
文摘The efforts in this study are made to demonstrate how an EFL teacher should develop and adapt the ESP reading materials to meet their English majors’needs and the social contexts where the learners are going to work.Based on a study of literature about material development and a case analysis of the teaching situation and students’profile,five criteria are proposed for selecting and adapting materials suitable for 3rd-year Hainan University English majors,and then an evaluation of the reading texts of the course book English for Tourism and Hospitality is made with these yardsticks.In view of the discussion and analysis,suggestions about ESP reading material development are put forth.
基金supported in part by the Australian Research Council Discovery Early Career Researcher Award(DE200101128)。
文摘Platooning represents one of the key features that connected automated vehicles may possess as it allows multiple automated vehicles to be maneuvered cooperatively with small headways on roads. However, a critical challenge in accomplishing automated vehicle platoons is to deal with the effects of intermittent and sporadic vehicle-to-vehicle data transmissions caused by limited wireless communication resources. This paper addresses the co-design problem of dynamic event-triggered communication scheduling and cooperative adaptive cruise control for a convoy of automated vehicles with diverse spacing policies. The central aim is to achieve automated vehicle platooning under various gap references with desired platoon stability and spacing performance requirements, while simultaneously improving communication efficiency. Toward this aim, a dynamic event-triggered scheduling mechanism is developed such that the intervehicle data transmissions are scheduled dynamically and efficiently over time. Then, a tractable co-design criterion on the existence of both the admissible event-driven cooperative adaptive cruise control law and the desired scheduling mechanism is derived. Finally, comparative simulation results are presented to substantiate the effectiveness and merits of the obtained results.
基金supported in part by the National Natural Science Foundation of China(62222301, 62073085, 62073158, 61890930-5, 62021003)the National Key Research and Development Program of China (2021ZD0112302, 2021ZD0112301, 2018YFC1900800-5)Beijing Natural Science Foundation (JQ19013)。
文摘Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.
基金supported by the National Natural Science Foundation of China(Grant No.62277032,62231017,62071254)Education Scientific Planning Project of Jiangsu Province(Grant No.B/2022/01/150)Jiangsu Provincial Qinglan Project,the Special Fund for Urban and Rural Construction and Development in Jiangsu Province.
文摘More and more accounts or devices are shared by multiple users in video applications,which makes it difficult to provide recommendation service.Existing recommendation schemes overlook multiuser sharing scenarios,and they cannot make effective use of the mixed information generated by multi-user when exploring users’potential interests.To solve these problems,this paper proposes an adaptive program recommendation system for multi-user sharing environment.Specifically,we first design an offline periodic identification module by building multi-user features and periodically predicting target user in future sessions,which can separate the profile of target user from mixed log records.Subsequently,an online recommendation module with adaptive timevarying exploration strategy is constructed by jointly using personal information and multi-user social information provided by identification module.On one hand,to learn the dynamic changes in user-interest,a time-varying linear upper confidence bound(LinUCB)based on personal information is designed.On the other hand,to reduce the risk of exploration,a timeinvariant LinUCB based on separated multi-user social information from one account/device is proposed to compute the quality scores of programs for each user,which is integrated into the time-varying LinUCB by cross-weighting strategy.Finally,experimental results validate the efficiency of the proposed scheme.
基金supported by the National Natural Science Foundation of China(12103057,12127901)the Frontier Research Fund of the Institute of Optics and Electronics,Chinese Academy of Sciences(C21K002)+1 种基金the Youth Innovation Promotion Association,Chinese Academy of Sciences(2021378)the National Natural Science Foundation of China(U2031148)。
文摘The 2.5 m wide-field and high-resolution solar telescope(WeHoST)is currently under developing for solar observations.WeHoST aims to achieve high-resolution observations over a super-wide field of view(FOV)of5′×5′,and a desired resolution of 0.3″.To meet the scientific requirements of WeHoST,the ground-layer adaptive optics(GLAO)with a specially designed wave front sensing system is as the primary consideration.We introduce the GLAO configuration,particularly the wave front sensing scheme.Utilizing analytic method,we simulate the performance of both classical AO and GLAO systems,optimize the wave front sensing system,and evaluate GLAO performance in terms of PSF uniformity and correction improvement across whole FOV.The results indicate that,the classical AO will achieve diffraction-limited resolution;the suggested GLAO configuration will uniformly improve the seeing across the full 5′×5′FOV,reducing the FWHM across the axis FOV to less than0.3″(λ≥705 nm,r0≥11 cm),which is more than two times improvement.The specially designed wave front sensor schedule offers new potential for WeHoST’s GLAO,particularly the multi-FOV GLAO and the flexibility to select the detected area.These capabilities will significantly enhance the scientific output of the telescope.
基金supported by grants from the National Natural Science Foundation of China(NSFC)to YD(32171129)from China Postdoctoral Science Foundation to YC(2023M731112)from NSFC to RG(32260216)。
文摘Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise has long been an area of active research.Studies of the vertebrate locomotor system’s adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during exercise.In this brief review,we highlight recent results and insights from the field with a focus on the following mechanisms:(a)alterations in neuronal excitability during acute exercise;(b)alterations in neuronal excitability after chronic exercise;(c)exercise-induced changes in neuronal membrane properties via modulation of ion channel activity;(d)exercise-enhanced dendritic plasticity;and(e)exercise-induced alterations in neuronal gene expression and protein synthesis.Our hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise.
基金This work was supported by the National Natural Science Foundation of China(U1602266,32060474,and 31601274)grants from the Yunnan Provincial Science and Technology Department(202005AF150009 and 202101AS070001).
文摘Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the OsNCED2 gene between upland and irrigated populations.A nonsynonymous mutation(C to T,from irrigated to upland rice)may have led to functional variation fixed by artificial selection,but the exact biological function in dryland adaptation is unclear.In this study,transgenic and association analysis indicated that the domesticated fixed mutation caused functional variation in OsNCED2,increasing ABA levels,root development,and drought tolerance in upland rice under dryland conditions.OsNCED2-overexpressing rice showed increased reactive oxygen species-scavenging abilities and transcription levels of many genes functioning in stress response and development that may regulate root development and drought tolerance.OsNCED2^(T)-NILs showed a denser root system and drought resistance,promoting the yield of rice under dryland conditions.OsNCED2^(T)may confer dryland adaptation in upland rice and may find use in breeding dryland-adapted,water-saving rice.
基金partially supported by the Natural Science Foundation of China (Grant Nos.62103052,52272358)partially supported by the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘This paper investigates the adaptive trajectory tracking control problem and the unknown parameter identification problem of a class of rotor-missiles with parametric system uncertainties.First,considering the uncertainty of structural and aerodynamic parameters,the six-degree-of-freedom(6Do F) nonlinear equations describing the position and attitude dynamics of the rotor-missile are established,respectively,in the inertial and body-fixed reference frames.Next,a hierarchical adaptive trajectory tracking controller that can guarantee closed-loop stability is proposed according to the cascade characteristics of the 6Do F dynamics.Then,a memory-augmented update rule of unknown parameters is proposed by integrating all historical data of the regression matrix.As long as the finitely excited condition is satisfied,the precise identification of unknown parameters can be achieved.Finally,the validity of the proposed trajectory tracking controller and the parameter identification method is proved through Lyapunov stability theory and numerical simulations.
基金the National Natural Science Foundation of China(No.52275062)and(No.52075262).
文摘Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.
基金supported by the National Key Research and Development Program(2022YFD2400804)National Natural Science Foundation of China(32022086,31972822)Natural Science Foundation of Shanghai(20ZR1417500)。
文摘Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present study,we discovered that the Nile tilapia(Oreochromis niloticus)encodes key components of the LAT signalosome,namely,LAT,ITK,GRB2,VAV1,SLP-76,GADS,and PLC-γ1.These components are evolutionarily conserved,and CD3εmAb-induced T-cell activation markedly increased their expression.Additionally,at least ITK,GRB2,and VAV1 were found to interact with LAT for signalosome formation.Downstream of the first signal,the NF-κB,MAPK/ERK,and PI3K-AKT pathways were activated upon CD3εmAb stimulation.Furthermore,treatment of lymphocytes with CD28 mAbs triggered the AKT-mTORC1 pathway downstream of the co-stimulatory signal.Combined CD3εand CD28 mAb stimulation enhanced ERK1/2 and S6 phosphorylation and elevated NFAT1,c-Fos,IL-2,CD122,and CD44 expression,thereby signifying T-cell activation.Moreover,rather than relying on the first or co-stimulatory signal alone,both signals were required for T-cell proliferation.Full T-cell activation was accompanied by marked apoptosis and cytotoxic responses.These findings suggest that tilapia relies on dual signaling to maintain an optimal T-cell response,providing a novel perspective for understanding the evolution of the adaptive immune system.