The smart card-based automated fare collection （AFC） system has become the main method for collecting urban bus and rail transit fares in many cities worldwide. Such smart card technologies provide new opportunities...The smart card-based automated fare collection （AFC） system has become the main method for collecting urban bus and rail transit fares in many cities worldwide. Such smart card technologies provide new opportunities for transportation data collection since the transaction data obtained through AFC system contains a significant amount of archived information which can be gathered and leveraged to help estimate public transit origin–destination matrices. Boarding location detection is an important step particularly when there is no automatic vehicle location （AVL） system or GPS information in the database in some cases. With the analysis of raw data without AVL information in this paper, an algorithm for trip direction detection is built and the directions for any bus in operation can be confirmed. The transaction interval between each adjacent record will also be analyzed to detect the boarding clusters for all trips in sequence. Boarding stops will then be distributed with the help of route information and operation schedules. Finally, the feasibility and practicality of the methodology are tested using the bus transit smart card data collected in Guangzhou, China.展开更多
The monitoring of power consumption has become of a great interest in recent years as well as the innovative technologies available to realize Wireless Sensor Networks (WSNs) have experienced a great growth. While sma...The monitoring of power consumption has become of a great interest in recent years as well as the innovative technologies available to realize Wireless Sensor Networks (WSNs) have experienced a great growth. While smart metering technologies for electric energy are already established, as sensors power supply comes directly from power lines, WSN nodes for gas metering should necessarily be equipped with long life batteries. The presented work describes a new prototypal low cost WSN designed ad hoc for gas smart metering. The network has a star topology: each sensor node can be completely integrated with standard reed relay gas meter, and it is capable to measure the gas consumption. The information is sent to the central node (the Access Point, AP) through an RF links. The sensor nodes have been designed with custom electronics and a proprietary firmware, in order to work with a common 3.6 V lithium battery which is able to ensure a life period of about 10 years for each node. Only the AP must be connected directly to electric power. The AP is connected through the RS-232 interface to a control embedded PC equipped with a LAMP (Linux, Apache, MySQL, PHP) framework: it stores all the information coming from each node in a coherent database and allows authorized users to check the network status using a web interface. The WSN is self-learning and it is capable to detect new nodes joining the network without altering the normal operative flow. Moreover e-mail and SMS alerts can be activated to alert if a node is disconnected from the network or some problems occur. A first prototype of the WSN has been already tested achieving good results.展开更多
本文基于对电动汽车快速充电的目的,设计了一台额定功率为8 k W的样机。输入为单相交流市电,采用AC-DC和DC-DC相结合的电路结构,利用DSP进行控制。通过与沃特玛BMS结合所做的充电实验,可以看出该样机具有结构简单、安全可靠的优点,满载...本文基于对电动汽车快速充电的目的,设计了一台额定功率为8 k W的样机。输入为单相交流市电,采用AC-DC和DC-DC相结合的电路结构,利用DSP进行控制。通过与沃特玛BMS结合所做的充电实验,可以看出该样机具有结构简单、安全可靠的优点,满载时输出电压纹波低于5%,效率可达到87%左右,能满足电动汽车快速充电的要求。展开更多
基金The United States Department of Transportation, University Transportation Center through the Center for Advanced Multimodal Mobility Solutions and Education (CAMMSE) at The University of North Carolina at Charlotte (Grant Number: 69A3551747133) for sponsoring this research project entitled ‘estimation of origin–destination matrix and identification of user activities using public transit smart card data’
文摘The smart card-based automated fare collection （AFC） system has become the main method for collecting urban bus and rail transit fares in many cities worldwide. Such smart card technologies provide new opportunities for transportation data collection since the transaction data obtained through AFC system contains a significant amount of archived information which can be gathered and leveraged to help estimate public transit origin–destination matrices. Boarding location detection is an important step particularly when there is no automatic vehicle location （AVL） system or GPS information in the database in some cases. With the analysis of raw data without AVL information in this paper, an algorithm for trip direction detection is built and the directions for any bus in operation can be confirmed. The transaction interval between each adjacent record will also be analyzed to detect the boarding clusters for all trips in sequence. Boarding stops will then be distributed with the help of route information and operation schedules. Finally, the feasibility and practicality of the methodology are tested using the bus transit smart card data collected in Guangzhou, China.
文摘The monitoring of power consumption has become of a great interest in recent years as well as the innovative technologies available to realize Wireless Sensor Networks (WSNs) have experienced a great growth. While smart metering technologies for electric energy are already established, as sensors power supply comes directly from power lines, WSN nodes for gas metering should necessarily be equipped with long life batteries. The presented work describes a new prototypal low cost WSN designed ad hoc for gas smart metering. The network has a star topology: each sensor node can be completely integrated with standard reed relay gas meter, and it is capable to measure the gas consumption. The information is sent to the central node (the Access Point, AP) through an RF links. The sensor nodes have been designed with custom electronics and a proprietary firmware, in order to work with a common 3.6 V lithium battery which is able to ensure a life period of about 10 years for each node. Only the AP must be connected directly to electric power. The AP is connected through the RS-232 interface to a control embedded PC equipped with a LAMP (Linux, Apache, MySQL, PHP) framework: it stores all the information coming from each node in a coherent database and allows authorized users to check the network status using a web interface. The WSN is self-learning and it is capable to detect new nodes joining the network without altering the normal operative flow. Moreover e-mail and SMS alerts can be activated to alert if a node is disconnected from the network or some problems occur. A first prototype of the WSN has been already tested achieving good results.
文摘本文基于对电动汽车快速充电的目的,设计了一台额定功率为8 k W的样机。输入为单相交流市电,采用AC-DC和DC-DC相结合的电路结构,利用DSP进行控制。通过与沃特玛BMS结合所做的充电实验,可以看出该样机具有结构简单、安全可靠的优点,满载时输出电压纹波低于5%,效率可达到87%左右,能满足电动汽车快速充电的要求。
