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ABSTRACT: We present DTMon, a dynamic traffic monitoring system using vehicular networks, and analyze its performance in free flow (i.e., non-congested) traffic. DTMon uses roadside infrastructure to gather and report current traffic conditions to traffic management centers and equipped vehicles. We analyze how traffic characteristics such as speed, flow rate, percentage of communicating vehicles, and distance from the DTMon measurement point to the roadside infrastructure affects the amount and quality of data that can be gathered and delivered. We evaluate five different methods of delivering data from vehicles to the roadside infrastructure, including pure vehicle-to-vehicle communication, store-and-carry, and hybrid methods. Methods that employ some amount of store-and-carry can increase the delivery rate, but also increase the message delay. We show that with just a few pieces of roadside infrastructure, DTMon can gather high-quality travel time and speed data even with a low percentage of communicating vehicles.
Consumer Communications and Networking Conference (CCNC), 2011 IEEE; 02/2011
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ABSTRACT: We evaluate the performance of the DTMon dynamic traffic monitoring system to measure travel times and speeds in transient flow traffic caused by non-recurring congestion. DTMon uses vehicular networks and roadside infrastructure to collect data from passing vehicles. We show DTMon's ability to gather high-quality real-time traffic data such as travel time and speed. These metrics can be used to detect transitions in traffic flow (e.g., caused by congestion) especially where accurate flow rate information is not available. We evaluate the accuracy and latency of DTMon in providing traffic measurements using two different methods of message delivery. We show the advantages of using dynamically-defined measurement points for monitoring transient flow traffic. We compare DTMon with currently in-use probe-based systems (e.g., AVL) and fixed-point sensors and detectors (e.g., ILD).
Vehicular Networking Conference (VNC), 2010 IEEE; 01/2011
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ABSTRACT: Location, fundamental information, plays a critical role in many applications and network routings in Vehicular Adhoc NETworks (VANETs). Therefore, it is of importance to validate the location information. We propose a cross-layer design to achieve location validation. We assume vehicles are installed with radar, GPS and transceiver. On physical layer, radar detection can validate GPS coordinates. On network layer, an agreement of a location can be achieved. On application layer, location information as a set of measurements can be filtered and refined by using a proposed data fusion method. We also present results of simulations and evaluate the location validation methods.
Intelligent Vehicles Symposium (IV), 2010 IEEE; 07/2010
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ABSTRACT: The past decade has witnessed the confluence of Intelligent Transportation Systems (ITS) and Vehicular Ad hoc Networks (VANET) that promises to revolutionize incident detection and the timely dissemination of traffic-related information to the various interested parties. One of the key components is expected to be a Cooperative Collision Warning System (CCWS). Our main contribution is to derive analytical expressions for key CCWS metrics that rely on mobility information exchanged by various players. The feasibility of CCWS has been demonstrated in previous work; this paper analyzes the mobility parameters and derives the conditional probability of a collision. We begin by proposing a set of fundamental parameters for CCWS: conditional probability of collision, headway distance, driver reaction time, relative velocity and acceleration. Preliminary simulation results have demonstrated the effectiveness of our analytical derivations.
Intelligent Vehicles Symposium (IV), 2010 IEEE; 07/2010
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ABSTRACT: In this paper, we propose an algorithm for joint adaptation of transmission power and contention window to improve the performance of vehicular network in a cross layer approach. The high mobility of vehicles in vehicular communication results in the change in topology of the Vehicular Ad-hoc Network (VANET) dynamically, and the communication link between two vehicles might remain active only for short duration of time. In order for VANET to make a connection for long time and to mitigate adverse effects due to high and fixed transmission power, the proposed algorithm adapts transmission power dynamically based on estimated local traffic density. In addition to that, the prioritization of messages according to their urgency is performed for timely propagation of high priority messages to the destination region. In this paper, we incorporate the contention based MAC protocol 802.11e enhanced distributed channel access (EDCA) mechanism to implement a priority-based vehicle-to-vehicle (V2V) communication. Simulation results show that the proposed algorithm is successful in getting better throughput with lower average end-to-end delay than the algorithm with static/default parameters.
Vehicular Technology Conference Fall (VTC 2009-Fall), 2009 IEEE 70th; 10/2009
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ABSTRACT: Parking is costly and limited in almost every major city in the world. The misparking aggravates the competition of parking slots. Innovative parking systems for meeting near-term parking demand are needed. A probabilistic approach is addressed to model the misparking of the current parking system. To provide an intelligent parking services and to eliminate the misparking, a wireless-based parking service is proposed. The proposed system adopts the wireless network and sensor technologies to provide an intelligent and automatic parking service. The implementation and a probabilistic analysis of the new parking service are presented as well.
Service Operations, Logistics and Informatics, 2009. SOLI '09. IEEE/INFORMS International Conference on; 08/2009
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ABSTRACT: Parking is costly and limited in almost every major city in the world. Innovative parking systems for meeting near-term parking demand are needed. In this paper, we propose a novel, secure and intelligent parking system based on the concept and framework of NOTICE [WO07], a secure and privacy-aware architecture for the notification of traffic incidents. The proposed system, called SmartParking, is a service-oriented intelligent parking system through which drivers can view and reserve a parking spot on the fly. The parking process can then be a straightforward and non-stop process. More importantly, SmartParking is a secure and privacy-aware parking system. The proposed infrastructure prevents most security/privacy attacks. We address hardware/software architecture and implementations. The evaluation of this proposed system proves its efficiency.
Intelligent Transportation Systems, 2008. ITSC 2008. 11th International IEEE Conference on; 11/2008
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ABSTRACT: We introduce NOTICE, a secure, privacy-aware architecture for the notification of traffic incidents. Using sensor belts embedded in the roadway, traffic-related messages and advisories are carried between belts by passing cars. NOTICE moves the responsibility for making decisions about traffic- related information dissemination to the infrastructure rather than leaving those decisions with the vehicles, which may have incomplete or incorrect knowledge. Extensive simulation showed that NOTICE can provide "up-to-the-minute" notification of road incidents.
Vehicular Technology Conference, 2008. VTC Spring 2008. IEEE; 06/2008
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ABSTRACT: This paper proposes a novel chaos reducing information dissemination approach for spatio-temporal traffic information related to first responders and evacuation scenarios using Vehicular Ad Hoc Networks (VANETs). In our approach, we provide an emergency vehicle path clearing technique. Therefore, traffic confusion and chaos is lowered on evacuation and emergency vehicle routes. Simulation results show that our approach works efficiently without fully relying on any message relaying infrastructure.
Vehicular Technology Conference, 2007. VTC-2007 Fall. 2007 IEEE 66th; 11/2007
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ABSTRACT: Disasters, natural and man-made alike, pose a serious threat to the nation by taking a heavy toll in human lives, destroying the public infrastructure and production capacity, interrupting supply lines, and stalling economic activity. One of the time-honored strategies for dealing with predictable natural disasters is a planned evacuation of the population from the afflicted area. Thus, evacuation strategies and supporting infrastructure are of the highest importance for mitigating the effects of such events. The main contribution of this work is to propose an intelligent highway infrastructure in support of planned evacuations. Specifically, we show that the recently-proposed architecture for the notification of traffic incidents and congestion (NOTICE) can be enhanced to support the needs of large-scale evacuations.
Performance, Computing, and Communications Conference, 2007. IPCCC 2007. IEEE Internationa; 05/2007
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ABSTRACT: This paper proposes an efficient chaos-reducing information dissemination approach for spatiotemporal traffic information related to first responders and planned evacuation scenarios using vehicular ad hoc networks (VANETs). VANETs have recently been proposed as one of the promising ad-hoc networking techniques that can be used to provide a safe and enjoyable driving experience. In our approach, we provide an emergency vehicle path clearing technique, and real-time resource (e.g. shelter) availability information. Therefore, traffic confusion and chaos is lowered on evacuation and emergency vehicle routes. Simulation results show that our approach works efficiently without fully relying on any message relaying infrastructure.
Performance, Computing, and Communications Conference, 2007. IPCCC 2007. IEEE Internationa; 05/2007
