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Prediction of Commuter Vehicle Demand Torque Based on Historical Speed Information
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作者 Shiji Sun Mingxin Kang Yuzhe Li 《Journal of Beijing Institute of Technology》 EI CAS 2022年第4期362-370,共9页
The development of vehicle-to-everything and cloud computing has brought new opportunities and challenges to the automobile industry.In this paper,a commuter vehicle demand torque prediction method based on historical... The development of vehicle-to-everything and cloud computing has brought new opportunities and challenges to the automobile industry.In this paper,a commuter vehicle demand torque prediction method based on historical vehicle speed information is proposed,which uses machine learning to predict and analyze vehicle demand torque.Firstly,the big data of vehicle driving is collected,and the driving data is cleaned and features extracted based on road information.Then,the vehicle longitudinal driving dynamics model is established.Next,the vehicle simulation simulator is established based on the longitudinal driving dynamics model of the vehicle,and the driving torque of the vehicle is obtained.Finally,the travel is divided into several accelerationcruise-deceleration road pairs for analysis,and the vehicle demand torque is predicted by BP neural network and Gaussian process regression. 展开更多
关键词 demand torque prediction commuter vehicle historical driving data machine learning
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Analysis of GHG Emissions for City Passenger Trains: Is Electricity an Obvious Option for Montreal Commuter Trains?
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作者 Sabrina Chan Luis Miranda-Moreno Zachary Patterson 《Journal of Transportation Technologies》 2013年第2期17-29,共13页
Alternative technologies have emerged to reduce the greenhouse gas (GHG) emissions of traditional commuter rail systems powered by diesel. Even larger reductions can be obtained with energy production from renewable r... Alternative technologies have emerged to reduce the greenhouse gas (GHG) emissions of traditional commuter rail systems powered by diesel. Even larger reductions can be obtained with energy production from renewable resources. This paper uses the commuter rail system in Montreal, Quebec, as a case study for implementing alternative technologies, namely, complete electrification of the network (only one of the existing five lines is electrified) and hydrogen fuel cell-powered trains. It is important to note that the main source of electricity generation in Quebec is hydropower which is offered at a relatively low cost. Several criteria were considered to determine the most suitable alternative including GHG emissions from operation and fuel production, operation and capital costs, and technological and commercial viability. Electrification of the commuter rail system would decrease annual emissions by 98% which is more than 27,000 tons. The GHG reductions for hydrogen trains are lower than electric trains but still substantial. The operation costs favor the electrification scenario;however, the high costs of electrical infrastructure make hydrogen trains more competitive since additional infrastructure is unnecessary. However, hydrogen trains remain a new and unproven technology;uncertainties associated with it should be settled before full implementation. 展开更多
关键词 Alternative Technologies commuter RAIL GREENHOUSE Gases
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First Aid Kit Uses among Commuter Bus Attendants in Nyamagana District, Mwanza City
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作者 Namanya Basinda Giveness Zacharia +2 位作者 Joshua Patrick Ngimbwa Joshua Patrick Ngimbwa Stanley Mwita 《Open Journal of Epidemiology》 2022年第3期274-284,共11页
Introduction: Provision of prehospital care in the event of a crash is vital to prevent loss of life and other severe outcomes. However, this involves adequate first aid knowledge and skills among vehicle attendants, ... Introduction: Provision of prehospital care in the event of a crash is vital to prevent loss of life and other severe outcomes. However, this involves adequate first aid knowledge and skills among vehicle attendants, and most importantly, the availability of the first aid kit items and knowing their uses. The aim of this study was to determine the knowledge, availability, and use of first aid kits among commuter bus attendants. Methods: This cross-sectional study was conducted in Nyamagana district, Mwanza, Tanzania in May 2018. A total of 240 were recruited randomly and interviewed using pretested questionnaires. Data was first entered in Microsoft Excel for data cleaning and consistent checks and thereafter exported to the software STATA for analysis. Results: Findings from the study showed that 22.9% of respondents had knowledge concerning first aid practice. Only 17.9% of the participants claimed to have ever had first aid training. All commuters had incompletely equipped first aid kits. Around 30.8% of the respondents reported having practiced giving first aid. Conclusion: The majority of commuter bus attendants were found to have insufficient knowledge of first aid and first aid kits, according to the current study. No vehicle had a complete kit despite the fact that the majority of the participants believed that having a first aid kit in the vehicle was essential. The majority of participants expressed a desire to assist and learn, indicating that efforts to train commuter attendants should be undertaken and potentially save lives. 展开更多
关键词 First Aid Kit First Aid Prehospital Care commuter Buses Mwanza
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Analysis of Benzene Exposure Levels on Commuters Traveling within the Metropolitan Area of Costa Rica
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作者 Wendy Villalobos-Gonzalez Germain Esquivel-Hernandez +2 位作者 Ricardo Sanchez-Murillo José Leonardo Corrales-Salazar Juan Valdes-Gonzalez 《Open Journal of Air Pollution》 2015年第1期38-46,共9页
This study reports the benzene exposure levels of commuters traveling within the metropolitan area of Costa Rica using personal cars, buses, and urban trains. 47 in-vehicle samples were collected in the 2014 wet seaso... This study reports the benzene exposure levels of commuters traveling within the metropolitan area of Costa Rica using personal cars, buses, and urban trains. 47 in-vehicle samples were collected in the 2014 wet season under three different driving conditions: rush hour traffic, normal traffic and weekends. Samples were collected in Tedlar bags and analyzed using 75 μm carboxenpolydimethylsiloxane (CAR/PDMS) and gas chromatography with flame ionization detection (GC-FID). Additionally, duplicate samples were collected on adsorption tubes filled with Tenax TA and analyzed by thermal desorption (TD) and GC-FID. Results indicate that travelling in cars and buses under rush hour conditions exposes commuters to statistically equal average benzene concentration of 48.7 and 51.6 μg/m3, respectively. Average benzene levels in urban trains (33.0 μg/m3) were measured only during morning rush hours. Greater benzene levels in buses than personal cars concentrations may be attributable to the immersion of traffic-related emission within the bus cabins. Factors, such as the driving pattern, the number of vehicles on the route, the road infrastructure, and the prevalence of gasoline-fueled vehicles in Costa Rica, may increase ambient benzene concentrations. Benzene levels inside car cabins reported in this study are in the range of those reported in other urban areas;however, the corresponding concentrations inside buses and urban trains (rush hour only) are higher than previously published exposure levels. 展开更多
关键词 Costa Rica Benzene EXPOSURE LEVELS Solid Phase MICROEXTRACTION (SPME) Traffic Hours commuterS EXPOSURE
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An Analysis of the Women Commuters’ Satisfaction in the Public Bus Service in Bangladesh: A Survey on Local Buses in Major Cities
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作者 Ayesha Umme Kojima Aya Kubota Hisashi 《Journal of Transportation Technologies》 2022年第4期559-577,共19页
Bangladesh is one of the most populated developing countries where public bus service plays a vital role as a public transport mode since it is easily available and cost-effective. In the social, commercial, education... Bangladesh is one of the most populated developing countries where public bus service plays a vital role as a public transport mode since it is easily available and cost-effective. In the social, commercial, educational, and administrative spheres, women’s participation in the labor force in economic enterprises is steadily expanding in the country. Very little research considers only women commuters to analyze the service quality of public buses and they selected only Dhaka city as a study area. However, a large number of trips were generated by women commuters in the industrial and commercial zones such as Gazipur, Narayanganj, and Dhaka. This paper ascertains the public bus service attributes that affect women commuters’ satisfaction as well as finds out the major problems of women commuters while traveling on public buses and the possible solutions to them. This survey included 766 women commuters from Dhaka, Narayanganj, and Gazipur who were interviewed face to face. Structural Equation Model (SEM) was used as the instrument for identifying the service quality (SQ) attributes that influenced the women commuters’ satisfaction. A series of models were developed based on the trial-and-error method and the model M<sub>3</sub> is selected as the best fit according to SEM fit indices values. The study’s main goal was to compile a list of service quality attributes that influence women commuters’ satisfaction. Major issues with the current public bus service in terms of safety and security, as well as remedies, were identified through discussions with experienced female commuters. These findings reveal that women commuters’ satisfaction is primarily influenced by safety and security, as well as the degree of comfort provided by bus service because they frequently encounter major safety and security issues on public buses and want an immediate remedy. This paper offers some potential strategies for addressing the issues, which may prompt policymakers to pay more attention to these aspects in transportation planning. 展开更多
关键词 Public Bus Service Quality Women commuters’ Satisfaction SEM
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Commuter exposure to BTEX in public transportation modes in Bangkok, Thailand
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作者 Maneerat Ongwandee Orathai Chavalparit 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第3期397-404,共8页
Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in ... Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in four public transportation modes in Bangkok, Thailand during two rush hour periods (7:00–9:00 a.m. and 4:00–7:00 p.m.). The four modes included an air-conditioned bus (A/C bus), non-air-conditioned bus (non-A/C bus), electric sky train, and a passenger boat traveling along the canal. Comparison among three important bus routes was also studied. In-vehicle air samples were collected using charcoal sorbent tubes and then analyzed by a gas chromatography-mass spectrometer. Results showed that the transportation modes significantly influenced the abundance of in-vehicle benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). Median concentrations of BTEX were 11.7, 103, 11.7, and 42.8 μg/m3 in A/C bus; 37.1, 174, 14.7, and 55.4 μg/m3 in non-A/C bus; 2.0, 36.9, 0.5, and 0.5 μg/m3 in sky train; and 3.1, 58.5, 0.5, and 6.2 μg/m3 in boat, respectively. Wilcoxon rank sum test indicated that toluene and m,p-xylene in the sky trains were statistically lower than that in the other three modes at a p-value of 0.05. There were statistical differences in TEX concentrations among the bus routes in the non-A/C buses. In addition, the benzene to toluene ratios implied that tail-pipe emissions were important contributor to the abundance of in-vehicle VOCs. 展开更多
关键词 BENZENE public transportation COMMUTING vehicle exhaust
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Choice behavior of commuters’rail transit mode during the COVID-19 pandemic based on logistic model 被引量:7
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作者 Limin Tan Changxi Ma 《Journal of Traffic and Transportation Engineering(English Edition)》 CSCD 2021年第2期186-195,共10页
To understand whether commuters will take rail transit during the COVID-19 pandemic,a logistic regression model was constructed from three aspects of personal attributes,travel attributes and perception of COVID-19 ba... To understand whether commuters will take rail transit during the COVID-19 pandemic,a logistic regression model was constructed from three aspects of personal attributes,travel attributes and perception of COVID-19 based on 559 valid questionnaires.The results show that:occupation,commuting tools before the COVID-19 pandemic,walking time from residence to the nearest subway station,the possibility of being infected in private car and the possibility of being infected in public transport have significant influence on the commuters’choice of rail transit.Self-employed people and freelancers,commuters who used non-public transport before the COVID-19 pandemic,and commuters who take longer to walk from their residences to the nearest subway station are less likely to commute by rail transit during the COVID-19 pandemic.Commuters who think that the risk of being infected with the virus in public transport is higher have a lower probability of choosing rail transit.The confidence in bus/subway/taxi/taxi-hailing of commuters who do not choose to commute by rail transit during the COVID-19 pandemic is not high.The study of this paper can provide reference for the formulation of urban rail transit control measures during the COVID-19 pandemic,so as to formulate more perfect measures to ensure the safety of the returning workers. 展开更多
关键词 Traffic engineering commuterS Rail transit QUESTIONNAIRE Influencing factors Logistic regression model
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Commuting Space of Primary and Secondary Schools in the Context of Child Friendly Cities:A Case Study of Bajiao Street of Shijingshan District
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作者 LIU Ping PENG Li +2 位作者 WANG Zhihao CONG Jing DING Yuqi 《Journal of Landscape Research》 2024年第1期22-26,30,共6页
With the continuous promotion of the construction of child friendly cities,the school commuting space is an important component of the construction of child friendly roads.Based on the background of child friendly cit... With the continuous promotion of the construction of child friendly cities,the school commuting space is an important component of the construction of child friendly roads.Based on the background of child friendly cities,the commuting space of 11 primary and secondary schools in Bajiao Street is analyzed through literature analysis and field research methods.Firstly,the relevant literature on school commuting space is sorted out,and the characteristics of school commuting space are summarized,including transportation,landscape,culture,leisure,and security.Secondly,the characteristics of commuting space of primary and secondary schools in Bajiao Street are analyzed from three aspects:in front of the school gate,path space,and node space.This paper aims to provide reference and guidance for the future construction of children’s walking school commuting and promote the construction of a child friendly city. 展开更多
关键词 Child friendly cities School commuting space Bajiao Street Primary and secondary schools
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Analysis of Commuting Modal Shift in Consideration of Social Interaction of Consciousness for Environment
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作者 Masashi Okushima 《Journal of Traffic and Transportation Engineering》 2024年第2期63-80,共18页
It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but ... It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but also consciousness for environmental problem of individual trip maker is important for eco-commuting promotion.On the other hand,consciousness for environment would be changed by influence of other person.Accordingly,it is aimed in the study that the structure of decision-making process for modal shift to the eco-commuting mode in the local city is described considering environmental consciousness and social interaction.For the purpose,the consciousness for the environment problem and the travel behavior of the commuter at the suburban area in the local city are investigated by the questionnaire survey.The covariance structure about the eco-consciousness is analyzed with the database of the questionnaire survey by structural equation modeling.As the result,it can be confirmed with the structural equation model that the individual environmental consciousness is strongly related with the intention of self-sacrifice and is influenced with the local interaction of the individual connections.On the other hand,the intention of modal shift for the commuting mode is analyzed with the database of the questionnaire survey.It can be found out that the environmental consciousness is not statistically significant for commuting mode choice with the present poor level of service of public transport.However,the intention of self-sacrifice for the prevention of the global warming is statistically confirmed as the factor of modal shift with the operation of eco-commuting bus service with the RP/SP integrated estimation method.As the result,the multi-agent simulation system with social interaction model for eco consciousness is developed to measure the effect of the eco-commuting promotion.For the purpose,the carbon dioxide emission is estimated based on traffic demand and road network condition in the traffic environment model.On the other hand,the relation between agents is defined based on the small world network.The proposed multi-agent simulation is applied to measure the effect of the eco-commuting promotion such as improvement of level of service on the public transport or education of eco-consciousness.The effect of the promotion plan can be observed with the proposed multi-agent system.Finally,it can be concluded that the proposed multi-agent simulation with social interaction for eco-consciousness is useful for planning of eco-commuting promotion. 展开更多
关键词 Greenhouse gas emission modal shift structural equation model RP/SP combined estimation multi-agent simulation local interaction small world network consciousness for environment commuting shuttle bus local city
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功能至尚 自在骑行——Levi’s~ Commuter系列,单车潮人必选潮品
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《东方电影》 2012年第8期58-59,共2页
近几年,环保健康的概念已越来越受年轻人的关注,众多年轻人选择了骑单车出行,这种最普及简单的出行工具已成为最潮的街头运动。单车运动一时间如同飓风一般席卷而来!怎样才能在骑行中仍旧保持最IN的造型。想必是热衷单车且对时尚敏感的... 近几年,环保健康的概念已越来越受年轻人的关注,众多年轻人选择了骑单车出行,这种最普及简单的出行工具已成为最潮的街头运动。单车运动一时间如同飓风一般席卷而来!怎样才能在骑行中仍旧保持最IN的造型。想必是热衷单车且对时尚敏感的潮人们最关心的问题了。如今Levi’s<sup>?</sup>透过聆听潮流单车族的心声,触发灵感,推出了一款适合走在潮流前端的单车族的产品,全新的Commuter系列,为风中的骑手量身打造,时尚和运动终于可以并户同行了! 展开更多
关键词 commuter Levi’s 潮人 车族 出行工具 专业功能 环保健康 环保日 行中 在黑暗中
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功能至尚 自在骑行——Levi’s~ Commuter系列,单车潮人必选潮品
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《东方电影》 2012年第7期78-79,共2页
近几年,环保健康的概念已越来越受年轻人的关注,众多年轻人选择了骑单车出行,这种最普及简单的出行工具已成为最潮的街头运动。单车运动一时间如同飓风一般席卷而来!怎样才能在骑行中仍旧保持最IN的造型。想必是热衷单车且对时尚敏感的... 近几年,环保健康的概念已越来越受年轻人的关注,众多年轻人选择了骑单车出行,这种最普及简单的出行工具已成为最潮的街头运动。单车运动一时间如同飓风一般席卷而来!怎样才能在骑行中仍旧保持最IN的造型。想必是热衷单车且对时尚敏感的潮人们最关心的问题了。如今LeVi’s<sup>?</sup>透过聆听潮流单车族的心声,触发灵感,推出了一款适合走在潮流前端的单车族的产品,全新的Commuter系列,为风中的骑手量身打造,时尚和运动终于可以并肩同行了! 展开更多
关键词 commuter Levi’s 出行工具 潮人 车族 行中 在黑暗中 环保健康 数字统计 单声
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The New Bike Sharing A Concept for Urban Commuters
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作者 Zhao Yang 《Voice of Friendship》 2017年第2期25-27,共3页
Shanghai saw the launch last April of bike-sharing startup MoBike,with its fleet of station-free bicycles distinguished by their app-activated rear-wheel locks.The company’s aim was to provide urban dwellers with aff... Shanghai saw the launch last April of bike-sharing startup MoBike,with its fleet of station-free bicycles distinguished by their app-activated rear-wheel locks.The company’s aim was to provide urban dwellers with affordable,convenient,short-distance transportation.The bikes were an immediate success.A few months later they 展开更多
关键词 bus The New Bike Sharing A Concept for Urban commuters
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Users’ Perception on Operation and Performance of Public Transport Systems in African Developing Countries: The Case of Bus Rapid Transit (BRT) in Dar es Salaam City, Tanzania
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作者 Emmanuel Elifadhili Mchome Uwezo Wilbard Nzoya 《Open Journal of Applied Sciences》 2023年第12期2408-2420,共13页
Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in ... Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops. 展开更多
关键词 Bus Rapid Transit commuters’ Perception Public Transport System
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Research on the Voltage Supporting Capability of Multi-VSC-HVDC Subsystems Operation Strategy to Receiving-end LCC-HVDC Network in Weak AC Grid 被引量:1
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作者 Tao Li Yongli Li Yuchen Zhu 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第1期11-20,共10页
For the hybrid multi-infeed HVDC system in which the receiving-end grid is a strong AC grid including LCC-HVDC subsystems and multiple VSC-HVDC subsystems,it has higher voltage support capability.However,for weak AC g... For the hybrid multi-infeed HVDC system in which the receiving-end grid is a strong AC grid including LCC-HVDC subsystems and multiple VSC-HVDC subsystems,it has higher voltage support capability.However,for weak AC grid,the voltage support capability of the multi-VSC-HVDC subsystems to the LCC-HVDC subsystem(voltage support capability-mVSCs-LCC)can resist the risk of commutation failure.Based on this consideration,this paper proposes an evaluation index called Dynamic Voltage Support Strength Factor(DVSF)for the hybrid multi-infeed system,and uses this index to qualitatively judge the voltage support capability-mVSCs-LCC in weak AC grid.In addition,the proposed evaluation index can also indirectly judge the ability of the LCC-HVDC subsystem to suppress commutation failure.Firstly,the mathematical model of the power flow of the LCC and VSC networks in the steady-state is analyzed,and the concept of DVSF applied to hybrid multi-infeed system is proposed.Furthermore,the DVSF index is also used to qualitatively judge the voltage support capability-mVSCs-LCC.Secondly,the influence of multiple VSC-HVDC subsystems with different operation strategies on the DVSF is analyzed with reference to the concept of DVSF.Finally,the indicators proposed in this paper are compared with other evaluation indicators through MATLAB simulation software to verify its effectiveness.More importantly,the effects of multi-VSC-HVDC subsystems using different coordinated control strategies on the voltage support capability of the receiving-end LCC-HVDC subsystem are also verified. 展开更多
关键词 Hybrid multi-infeed HVDC system Voltage support Multi-VSC-HVDC LCC-HVDC Commutation failure DVSF Control strategy
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THE FRACTIONAL TYPE MARCINKIEWICZ INTEGRALS AND COMMUTATORS ON WEIGHTED HARDY SPACES
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作者 韩妍妍 伍火熊 《Acta Mathematica Scientia》 SCIE CSCD 2023年第5期1981-1996,共16页
This paper is devoted to studying the behaviors of the fractional type Marcinkiewicz integralsμΩ,βand the commutatorsμΩ,βb generated byμΩ,βwith b b∈Lloc(Rn)on weighted Hardy spaces.Under the assumption of th... This paper is devoted to studying the behaviors of the fractional type Marcinkiewicz integralsμΩ,βand the commutatorsμΩ,βb generated byμΩ,βwith b b∈Lloc(Rn)on weighted Hardy spaces.Under the assumption of that the homogeneous kernelΩsatisfies certain regularities,the authors obtain the boundedness ofμΩ,βfrom the weighted Hardy spaces Hωpp(Rn)to the weighted Lebesgue spaces Lωqq(Rn)for n/(n+β)≤<p≤1 with 1/q=1/p-β/n,as well as the same(Hωpp,Lωqq)-boudedness ofμΩ,βb when b belongs to BMOωp,p(Rn),which is a non-trivial subspace of BMO(Rn). 展开更多
关键词 fractional type Marcinkiewicz integrals COMMUTATORS Muckenhoupt weights BMO spaces Hardy spaces
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BOUNDEDNESS AND COMPACTNESS FOR THE COMMUTATOR OF THEω-TYPE CALDER′ON-ZYGMUND OPERATOR ON LORENTZ SPACE
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作者 陶祥兴 曾媛 喻晓 《Acta Mathematica Scientia》 SCIE CSCD 2023年第4期1587-1602,共16页
In this paper,the authors consider theω-type Calder´on-Zygmund operator T_(ω)and the commutator[b,T_(ω)]generated by a symbol function b on the Lorentz space L^(p,r)(X)over the homogeneous space(X,d,μ).The bo... In this paper,the authors consider theω-type Calder´on-Zygmund operator T_(ω)and the commutator[b,T_(ω)]generated by a symbol function b on the Lorentz space L^(p,r)(X)over the homogeneous space(X,d,μ).The boundedness and the compactness of the commutator[b,T_(ω)]on Lorentz space L^(p,r)(X)are founded for any p∈(1,∞)and r∈[1,∞). 展开更多
关键词 ω-type Calder´on-Zygmund operator COMMUTATORS Lorentz space homogeneous space
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BAND-DOMINATED OPERATORS ON BERGMAN-TYPE SPACES
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作者 伍盛坤 郑德超 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期387-408,共22页
In this paper,we study band-dominated operators on Bergman-type spaces and prove that the C*-algebra of band-dominated operators is equal to the essential commutant of Toeplitz operators with a symbol in the set of bo... In this paper,we study band-dominated operators on Bergman-type spaces and prove that the C*-algebra of band-dominated operators is equal to the essential commutant of Toeplitz operators with a symbol in the set of bounded vanishing Lipschitz functions.On the Bergman space and the Fock space,we show that the C*-algebra of band-dominated operators equals the Toeplitz algebra. 展开更多
关键词 Band-dominated operators Bergman-type space Essential commutant
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BOUNDEDNESS OF THE CALDER´ON COMMUTATOR WITH A ROUGH KERNEL ON TRIEBEL-LIZORKIN SPACES
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作者 胡国恩 刘洁 《Acta Mathematica Scientia》 SCIE CSCD 2023年第4期1618-1632,共15页
In this paper,we consider the boundedness on Triebel-Lizorkin spaces for the d-dimensional Calder´on commutator defined by TΩ,af(x)=p.v.∫R_(d)Ω(x−y)/|x−y|^(d+1)(a(x)−a(y))f(y)dy,where Ω is homogeneous of degr... In this paper,we consider the boundedness on Triebel-Lizorkin spaces for the d-dimensional Calder´on commutator defined by TΩ,af(x)=p.v.∫R_(d)Ω(x−y)/|x−y|^(d+1)(a(x)−a(y))f(y)dy,where Ω is homogeneous of degree zero,integrable on Sd−1 and has a vanishing moment of order one,and a is a function on Rd such that∇a∈L^(∞)(R^(d)).We prove that if 1<p,q<∞andΩ∈L(log L)^(2 q)(S^(d−1))with q=max{1/q,1/q′},then TΩ,a is bounded on Triebel-Lizorkin spaces˙F_(p)^(0)q(R^(d)). 展开更多
关键词 Calder´on commutator Fourier transform Littlewood-Paley theory Calder´on reproducing formula
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带有对合的素环的微分恒等式
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作者 黄述亮 《Chinese Quarterly Journal of Mathematics》 2023年第2期134-144,共11页
Let R be a prime ring of characteristic different from two with the second involution∗andαan automorphism of R.An additive mapping F of R is called a generalized(α,α)-derivation on R if there exists an(α,α)-deriv... Let R be a prime ring of characteristic different from two with the second involution∗andαan automorphism of R.An additive mapping F of R is called a generalized(α,α)-derivation on R if there exists an(α,α)-derivation d of R such that F(xy)=F(x)α(y)+α(x)d(y)holds for all x,y∈R.The paper deals with the study of some commutativity criteria for prime rings with involution.Precisely,we describe the structure of R admitting a generalized(α,α)-derivation F satisfying any one of the following properties:(i)F(xx∗)−α(xx∗)∈Z(R),(ii)F(xx∗)+α(xx∗)∈Z(R),(iii)F(x)F(x∗)−α(xx∗)∈Z(R),(iv)F(x)F(x∗)+α(xx∗)∈Z(R),(v)F(xx∗)−F(x)F(x∗)∈Z(R),(vi)F(xx∗)−F(x∗)F(x)=0 for all x∈R.Also,some examples are given to demonstrate that the restriction of the various results is not superfluous.In fact,our results unify and extend several well known theorems in literature. 展开更多
关键词 Prime rings Generalized(α α)-derivations INVOLUTION COMMUTATIVITY
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顶点代数的Commutant S(V_4)^(Θ+)的一个共形向量(英文) 被引量:2
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作者 楚彦军 张小慧 《河南大学学报(自然科学版)》 CAS 北大核心 2010年第4期331-335,共5页
对于李代数sl(2,)的最高权为4的不可约表示V4,给出了βγ-系统commutantS(V4)Θ+的一个共形向量.在共形场论中,共形向量代表了某种共形场模型保持共形对称性.
关键词 顶点代数的Commutant βγ-系统 流代数 共形向量
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