This paper presents a Dynamic Cross-layer Data Queue Management approach (DC-DQM) based on priority to address the priority deviation problem in Delay-Tolerant Mobile Sensor Networks (DT-MSNs). Receiver-driven data de...This paper presents a Dynamic Cross-layer Data Queue Management approach (DC-DQM) based on priority to address the priority deviation problem in Delay-Tolerant Mobile Sensor Networks (DT-MSNs). Receiver-driven data delivery scheme is used for fast response to data transfers, and a priority based interaction model is adopted to identify the data priority. Three interactive parameters are introduced to prioritize and dynamically manage data queue. The experimental results show that it can ameliorate data delivery ratio and achieve good performance in terms of average delay.展开更多
In order to estimate vehicular queue length at signalized intersections accurately and overcome the shortcomings and restrictions of existing studies especially those based on shockwave theory,a new methodology is pre...In order to estimate vehicular queue length at signalized intersections accurately and overcome the shortcomings and restrictions of existing studies especially those based on shockwave theory,a new methodology is presented for estimating vehicular queue length using data from both point detectors and probe vehicles. The methodology applies the shockwave theory to model queue evolution over time and space. Using probe vehicle locations and times as well as point detector measured traffic states,analytical formulations for calculating the maximum and minimum( residual) queue length are developed. The proposed methodology is verified using ground truth data collected from numerical experiments conducted in Shanghai,China. It is found that the methodology has a mean absolute percentage error of 17. 09%,which is reasonably effective in estimating the queue length at traffic signalized intersections. Limitations of the proposed models and algorithms are also discussed in the paper.展开更多
Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could ...Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could be transmitted to navigation systems such as Waze. This study reports on the deployment and impact evaluation of digital alerts on motorist’s assistance patrols and 19 Queue trucks in Indiana. The motorist assistance patrol evaluation is provided qualitatively. A novel analysis of queue warning trucks equipped with digital alerts was conducted during the months of May-July in 2021 using connected vehicle data. This new data set reports locations of anonymous hard-braking events from connected vehicles on the Interstate. Hard-braking events were tabulated for when queueing occurred with and without the presence of a queue warning truck. Approximately 370 hours of queueing with queue trucks present and 58 hours of queueing without queue truck<span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> present were evaluated. Hard-braking events were found to decrease approximately 80% when queue warning trucks were used to alert motorists of impending queues.</span>展开更多
Network congestion, one of the challenging tasks in communication networks, leads to queuing delays, packet loss, or the blocking of new connections. In this study, a data portal is considered as an application-based ...Network congestion, one of the challenging tasks in communication networks, leads to queuing delays, packet loss, or the blocking of new connections. In this study, a data portal is considered as an application-based network, and a cognitive method is proposed to deal with congestion in this kind of network. Unlike previous methods for congestion control, the proposed method is an effective approach for congestion control when the link capacity and information inquiries are unknown or variable. Using sufficient training samples and the current value of the network parameters, available bandwidth is adjusted to distribute the bandwidth among the active flows. The proposed cognitive method was tested under such situations as unexpected variations in link capacity and oscillatory behavior of the bandwidth. Based on simulation results, the proposed method is capable of adjusting the available bandwidth by tuning the queue length, and provides a stable queue in the network.展开更多
Nowadays, we experience an abundance of Internet of Things middleware solutions that make the sensors and the actuators are able to connect to the Internet. These solutions, referred to as platforms to gain a widespre...Nowadays, we experience an abundance of Internet of Things middleware solutions that make the sensors and the actuators are able to connect to the Internet. These solutions, referred to as platforms to gain a widespread adoption, have to meet the expectations of different players in the IoT ecosystem, including devices [1]. Low cost devices are easily able to connect wirelessly to the Internet, from handhelds to coffee machines, also known as Internet of Things (IoT). This research describes the methodology and the development process of creating an IoT platform. This paper also presents the architecture and implementation for the IoT platform. The goal of this research is to develop an analytics engine which can gather sensor data from different devices and provide the ability to gain meaningful information from IoT data and act on it using machine learning algorithms. The proposed system is introducing the use of a messaging system to improve the overall system performance as well as provide easy scalability.展开更多
为解决命名数据网(Named Data Networking,NDN)中混合拥塞控制的过度控制问题,提出一种协同拥塞控制方案CHCC(Cooperative Hybrid Congestion Control),不仅支持接收端和路由器协同缓解拥塞,还能够防止由于两者过度控制导致的传输性能...为解决命名数据网(Named Data Networking,NDN)中混合拥塞控制的过度控制问题,提出一种协同拥塞控制方案CHCC(Cooperative Hybrid Congestion Control),不仅支持接收端和路由器协同缓解拥塞,还能够防止由于两者过度控制导致的传输性能下降。CHCC通过主动队列管理技术检测拥塞并产生标记信息,触发下游接收端调整Interest发送窗口、路由器转移流量来控制拥塞。在ndnSIM中实现该方案,并与ICP(Interest Control Protocol)方案进行对比,结果表明CHCC在多种拓扑下均能获得更高的吞吐量,更低、更稳定的传输延时,同时无丢包现象,此外,通过Jain's公平性指数进行公平评价,结果表明CHCC在确保用户间资源分配公平方面同样非常有效。展开更多
基金Supported by the Anhui Provincial Natural Science Foundation (No. 2012AKZR0330)Postdoctoral Science Foundation of China (No. 2012M521247)the Fundamental Research Funds for the Central Universities
文摘This paper presents a Dynamic Cross-layer Data Queue Management approach (DC-DQM) based on priority to address the priority deviation problem in Delay-Tolerant Mobile Sensor Networks (DT-MSNs). Receiver-driven data delivery scheme is used for fast response to data transfers, and a priority based interaction model is adopted to identify the data priority. Three interactive parameters are introduced to prioritize and dynamically manage data queue. The experimental results show that it can ameliorate data delivery ratio and achieve good performance in terms of average delay.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51138003)
文摘In order to estimate vehicular queue length at signalized intersections accurately and overcome the shortcomings and restrictions of existing studies especially those based on shockwave theory,a new methodology is presented for estimating vehicular queue length using data from both point detectors and probe vehicles. The methodology applies the shockwave theory to model queue evolution over time and space. Using probe vehicle locations and times as well as point detector measured traffic states,analytical formulations for calculating the maximum and minimum( residual) queue length are developed. The proposed methodology is verified using ground truth data collected from numerical experiments conducted in Shanghai,China. It is found that the methodology has a mean absolute percentage error of 17. 09%,which is reasonably effective in estimating the queue length at traffic signalized intersections. Limitations of the proposed models and algorithms are also discussed in the paper.
文摘Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could be transmitted to navigation systems such as Waze. This study reports on the deployment and impact evaluation of digital alerts on motorist’s assistance patrols and 19 Queue trucks in Indiana. The motorist assistance patrol evaluation is provided qualitatively. A novel analysis of queue warning trucks equipped with digital alerts was conducted during the months of May-July in 2021 using connected vehicle data. This new data set reports locations of anonymous hard-braking events from connected vehicles on the Interstate. Hard-braking events were tabulated for when queueing occurred with and without the presence of a queue warning truck. Approximately 370 hours of queueing with queue trucks present and 58 hours of queueing without queue truck<span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> present were evaluated. Hard-braking events were found to decrease approximately 80% when queue warning trucks were used to alert motorists of impending queues.</span>
文摘Network congestion, one of the challenging tasks in communication networks, leads to queuing delays, packet loss, or the blocking of new connections. In this study, a data portal is considered as an application-based network, and a cognitive method is proposed to deal with congestion in this kind of network. Unlike previous methods for congestion control, the proposed method is an effective approach for congestion control when the link capacity and information inquiries are unknown or variable. Using sufficient training samples and the current value of the network parameters, available bandwidth is adjusted to distribute the bandwidth among the active flows. The proposed cognitive method was tested under such situations as unexpected variations in link capacity and oscillatory behavior of the bandwidth. Based on simulation results, the proposed method is capable of adjusting the available bandwidth by tuning the queue length, and provides a stable queue in the network.
文摘Nowadays, we experience an abundance of Internet of Things middleware solutions that make the sensors and the actuators are able to connect to the Internet. These solutions, referred to as platforms to gain a widespread adoption, have to meet the expectations of different players in the IoT ecosystem, including devices [1]. Low cost devices are easily able to connect wirelessly to the Internet, from handhelds to coffee machines, also known as Internet of Things (IoT). This research describes the methodology and the development process of creating an IoT platform. This paper also presents the architecture and implementation for the IoT platform. The goal of this research is to develop an analytics engine which can gather sensor data from different devices and provide the ability to gain meaningful information from IoT data and act on it using machine learning algorithms. The proposed system is introducing the use of a messaging system to improve the overall system performance as well as provide easy scalability.
文摘为解决命名数据网(Named Data Networking,NDN)中混合拥塞控制的过度控制问题,提出一种协同拥塞控制方案CHCC(Cooperative Hybrid Congestion Control),不仅支持接收端和路由器协同缓解拥塞,还能够防止由于两者过度控制导致的传输性能下降。CHCC通过主动队列管理技术检测拥塞并产生标记信息,触发下游接收端调整Interest发送窗口、路由器转移流量来控制拥塞。在ndnSIM中实现该方案,并与ICP(Interest Control Protocol)方案进行对比,结果表明CHCC在多种拓扑下均能获得更高的吞吐量,更低、更稳定的传输延时,同时无丢包现象,此外,通过Jain's公平性指数进行公平评价,结果表明CHCC在确保用户间资源分配公平方面同样非常有效。
