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Special Issue "Vehicular Sensor Networks: Technical Challenges, Supports, and Application Experiences"

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Networks".

Deadline for manuscript submissions: closed (31 December 2016)

Special Issue Editor

Guest Editor
Prof. Dr. Paolo Bellavista

DISI - University of Bologna Viale del Risorgimento, 2 - 40136 Bologna - Italy
Website | E-Mail
Phone: +39-051-20 93866
Fax: +39-051-20 93953
Interests: middleware; mobile and pervasive computing; context-aware systems; network function virtualization; software defined infrastructures; orchestration of cloud and network resources; context-aware systems; Internet of Things; vehicular ad hoc networks

Special Issue Information

Dear Colleagues,

The development of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) based Vehicular Ad hoc Networks (VANETs) are interesting and active research areas nowadays, which is attracting significant efforts from both industry and academia, not only from the automotive and Intelligent Transportation Systems (ITSs) communities, but also from the fields of wireless and mobile sensor networks, smart environments, and mobile collaborative applications in general. In this context, many currently ongoing national and international collaboration projects practically demonstrate the relevant interest from government, industry, and academia in the field.

In particular, Vehicular Sensor Networks (VSNs) are becoming increasingly interesting and popular due to recent advances in inter-vehicular communication technologies and the decreasing cost of communication devices. Different from traditional wireless sensor nodes, vehicles are not typically affected by energy constraints and can easily be equipped with powerful processing units, wireless communication devices, GPS, and sensing devices, such as chemical detectors, still/video cameras, and vibration and acoustic sensors. Thus, they enable new and promising sensing applications, such as traffic reporting, relief to environmental monitoring, distributed surveillance, to mention a few promising (though not the most visionary) service provisioning scenarios.

The design, implementation, and deployment of dynamic, opportunistic, collaborative, scalable, efficient, reliable, robust, and secured mobile sensing applications for VSNs, especially over realistic and large-scale deployment environments, such as municipalities, present extraordinary challenges to the pervasive and mobile computing research community.

This Special Issue intends to disseminate the latest research results in this emergent research area, by providing a fresh snapshot of the current state-of-the-art in VANETs, VSNs, and mobile sensing. To this purpose, we are seeking high-quality papers reporting original research results and practical experiences of system design/prototyping/deployment related to topics that include, but are not limited to:

  • Original algorithms and protocols for VSN mobile sensing
  • Original middleware and platforms for the support of VSN applications
  • Case studies of mobile sensing applications over wide-scale urban environments
  • Vehicle-oriented crowdsensing and opportunistic participation
  • Vehicle-oriented mobile cloud computing and edge computing
  • Vehicular network architectures and protocols for mobile sensing
  • Intra-vehicular sensor network and integration with (possibly legacy) embedded systems
  • Routing, addressing, and transport-layer issues for mobile sensing
  • Efficient QoS support for quality-sensitive mobile sensing applications
  • Delay-tolerant and real-time supports for VSN mobile sensing
  • Data dissemination solutions for VSN mobile sensing applications
  • Performance, scalability, reliability, and efficiency of VSN supports and applications
  • Safety, enhanced navigation, and car alert supports/services
  • Vehicular collision avoidance using distributed sensing technologies
  • Human-machine interface for VSN mobile sensing applications
  • Mobility models and vehicle traffic models
  • Simulation aspects of V2V, V2I, and VSNs
  • Emulation and testbeds for large-scale VSNs
  • Practical experience with standards (802.11p, CALM, P1609, etc.), standard development and evolution
  • Security, encryption, and privacy for VSNs

Dr. Paolo Bellavista
Guest Editor

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Keywords

  • Vehicular Ad Hoc Networks (VANET)
  • Vehicular Sensor Networks (VSN)
  • Intelligent Transportation Systems (ITS)
  • Vehicle-to-Vehicle (V2V) Communications
  • Vehicle-to-Infrastructure (V2I) Communications
  • Opportunistic Collaborative Sensing
  • Middleware
  • Scalability
  • Wide-scale Application Experiences

Published Papers (13 papers)

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Research

Open AccessArticle Impact Analysis of Flow Shaping in Ethernet-AVB/TSN and AFDX from Network Calculus and Simulation Perspective
Sensors 2017, 17(5), 1181; doi:10.3390/s17051181
Received: 19 February 2017 / Revised: 17 May 2017 / Accepted: 17 May 2017 / Published: 22 May 2017
PDF Full-text (3003 KB) | HTML Full-text | XML Full-text
Abstract
Ethernet-AVB/TSN (Audio Video Bridging/Time-Sensitive Networking) and AFDX (Avionics Full DupleX switched Ethernet) are switched Ethernet technologies, which are both candidates for real-time communication in the context of transportation systems. AFDX implements a fixed priority scheduling strategy with two priority levels. Ethernet-AVB/TSN supports a
[...] Read more.
Ethernet-AVB/TSN (Audio Video Bridging/Time-Sensitive Networking) and AFDX (Avionics Full DupleX switched Ethernet) are switched Ethernet technologies, which are both candidates for real-time communication in the context of transportation systems. AFDX implements a fixed priority scheduling strategy with two priority levels. Ethernet-AVB/TSN supports a similar fixed priority scheduling with an additional Credit-Based Shaper (CBS) mechanism. Besides, TSN can support time-triggered scheduling strategy. One direct effect of CBS mechanism is to increase the delay of its flows while decreasing the delay of other priority ones. The former effect can be seen as the shaping restriction and the latter effect can be seen as the shaping benefit from CBS. The goal of this paper is to investigate the impact of CBS on different priority flows, especially on the intermediate priority ones, as well as the effect of CBS bandwidth allocation. It is based on a performance comparison of AVB/TSN and AFDX by simulation in an automotive case study. Furthermore, the shaping benefit is modeled based on integral operation from network calculus perspective. Combing with the analysis of shaping restriction and shaping benefit, some configuration suggestions on the setting of CBS bandwidth are given. Results show that the effect of CBS depends on flow loads and CBS configurations. A larger load of high priority flows in AVB tends to a better performance for the intermediate priority flows when compared with AFDX. Shaping benefit can be explained and calculated according to the changing from the permitted maximum burst. Full article
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Open AccessArticle A Vehicle Steering Recognition System Based on Low-Cost Smartphone Sensors
Sensors 2017, 17(3), 633; doi:10.3390/s17030633
Received: 10 January 2017 / Revised: 11 March 2017 / Accepted: 16 March 2017 / Published: 20 March 2017
PDF Full-text (8561 KB) | HTML Full-text | XML Full-text
Abstract
Recognizing how a vehicle is steered and then alerting drivers in real time is of utmost importance to the vehicle and driver’s safety, since fatal accidents are often caused by dangerous vehicle maneuvers, such as rapid turns, fast lane-changes, etc. Existing solutions using
[...] Read more.
Recognizing how a vehicle is steered and then alerting drivers in real time is of utmost importance to the vehicle and driver’s safety, since fatal accidents are often caused by dangerous vehicle maneuvers, such as rapid turns, fast lane-changes, etc. Existing solutions using video or in-vehicle sensors have been employed to identify dangerous vehicle maneuvers, but these methods are subject to the effects of the environmental elements or the hardware is very costly. In the mobile computing era, smartphones have become key tools to develop innovative mobile context-aware systems. In this paper, we present a recognition system for dangerous vehicle steering based on the low-cost sensors found in a smartphone: i.e., the gyroscope and the accelerometer. To identify vehicle steering maneuvers, we focus on the vehicle’s angular velocity, which is characterized by gyroscope data from a smartphone mounted in the vehicle. Three steering maneuvers including turns, lane-changes and U-turns are defined, and a vehicle angular velocity matching algorithm based on Fast Dynamic Time Warping (FastDTW) is adopted to recognize the vehicle steering. The results of extensive experiments show that the average accuracy rate of the presented recognition reaches 95%, which implies that the proposed smartphone-based method is suitable for recognizing dangerous vehicle steering maneuvers. Full article
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Open AccessArticle PAVS: A New Privacy-Preserving Data Aggregation Scheme for Vehicle Sensing Systems
Sensors 2017, 17(3), 500; doi:10.3390/s17030500
Received: 30 December 2016 / Revised: 20 February 2017 / Accepted: 27 February 2017 / Published: 3 March 2017
Cited by 2 | PDF Full-text (1057 KB) | HTML Full-text | XML Full-text
Abstract
Air pollution has become one of the most pressing environmental issues in recent years. According to a World Health Organization (WHO) report, air pollution has led to the deaths of millions of people worldwide. Accordingly, expensive and complex air-monitoring instruments have been exploited
[...] Read more.
Air pollution has become one of the most pressing environmental issues in recent years. According to a World Health Organization (WHO) report, air pollution has led to the deaths of millions of people worldwide. Accordingly, expensive and complex air-monitoring instruments have been exploited to measure air pollution. Comparatively, a vehicle sensing system (VSS), as it can be effectively used for many purposes and can bring huge financial benefits in reducing high maintenance and repair costs, has received considerable attention. However, the privacy issues of VSS including vehicles’ location privacy have not been well addressed. Therefore, in this paper, we propose a new privacy-preserving data aggregation scheme, called PAVS, for VSS. Specifically, PAVS combines privacy-preserving classification and privacy-preserving statistics on both the mean E(·) and variance Var(·), which makes VSS more promising, as, with minimal privacy leakage, more vehicles are willing to participate in sensing. Detailed analysis shows that the proposed PAVS can achieve the properties of privacy preservation, data accuracy and scalability. In addition, the performance evaluations via extensive simulations also demonstrate its efficiency. Full article
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Open AccessArticle Synthesizing Existing CSMA and TDMA Based MAC Protocols for VANETs
Sensors 2017, 17(2), 338; doi:10.3390/s17020338
Received: 18 December 2016 / Revised: 29 January 2017 / Accepted: 6 February 2017 / Published: 10 February 2017
PDF Full-text (624 KB) | HTML Full-text | XML Full-text
Abstract
Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies
[...] Read more.
Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies used in these MAC protocols are complementary. Based on this insight, we design CTMAC, a MAC protocol that synthesizes existing strategies; namely, random accessing channel (used in CSMA-style protocols) and arbitral reserving channel (used in TDMA-based protocols). CTMAC swiftly changes its strategy according to the vehicle density, and its performance is better than the state-of-the-art protocols. We evaluate CTMAC using at-scale simulations. Our results show that CTMAC reduces the channel completion time and increases the network goodput by 45% for a wide range of application workloads and network settings. Full article
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Open AccessArticle Multi-Objective Sliding Mode Control on Vehicle Cornering Stability with Variable Gear Ratio Actuator-Based Active Front Steering Systems
Sensors 2017, 17(1), 49; doi:10.3390/s17010049
Received: 16 November 2016 / Revised: 13 December 2016 / Accepted: 19 December 2016 / Published: 28 December 2016
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Abstract
Active front steering (AFS) is an emerging technology to improve the vehicle cornering stability by introducing an additional small steering angle to the driver’s input. This paper proposes an AFS system with a variable gear ratio steering (VGRS) actuator which is controlled by
[...] Read more.
Active front steering (AFS) is an emerging technology to improve the vehicle cornering stability by introducing an additional small steering angle to the driver’s input. This paper proposes an AFS system with a variable gear ratio steering (VGRS) actuator which is controlled by using the sliding mode control (SMC) strategy to improve the cornering stability of vehicles. In the design of an AFS system, different sensors are considered to measure the vehicle state, and the mechanism of the AFS system is also modelled in detail. Moreover, in order to improve the cornering stability of vehicles, two dependent objectives, namely sideslip angle and yaw rate, are considered together in the design of SMC strategy. By evaluating the cornering performance, Sine with Dwell and accident avoidance tests are conducted, and the simulation results indicate that the proposed SMC strategy is capable of improving the cornering stability of vehicles in practice. Full article
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Open AccessArticle TPLE: A Reliable Data Delivery Scheme for On-Road WSN Traffic Monitoring
Sensors 2017, 17(1), 44; doi:10.3390/s17010044
Received: 24 October 2016 / Revised: 11 December 2016 / Accepted: 20 December 2016 / Published: 27 December 2016
PDF Full-text (2426 KB) | HTML Full-text | XML Full-text
Abstract
In an on-road environment, motor-engines severely disturb the wireless link of a sensor node, leading to high package loss rate, high delivery delay, and poor radio communication quality. The existing data delivery mechanisms, such as the ACK-based retransmission mechanism and window-based link quality
[...] Read more.
In an on-road environment, motor-engines severely disturb the wireless link of a sensor node, leading to high package loss rate, high delivery delay, and poor radio communication quality. The existing data delivery mechanisms, such as the ACK-based retransmission mechanism and window-based link quality estimation mechanism, could not handle these challenges well. To solve this challenge, we propose a Target-Prediction-based Link quality Estimation scheme (TPLE) to realize high quality data delivery in an on-road environment. To perform on-road link quality estimation, TPLE dynamically calculates the track of a nearby vehicle target and estimates target impact on wireless link. Based on the local estimation of link quality, TPLE schedules radio communication tasks effectively. Simulations indicate that our proposed TPLE scheme produces a 94% data delivery rate, its average retransmission number is around 0.8. Our conducted on-road data delivery experiments also indicated a similar result as the computer simulation. Full article
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Open AccessArticle Threshold-Based Random Charging Scheme for Decentralized PEV Charging Operation in a Smart Grid
Sensors 2017, 17(1), 39; doi:10.3390/s17010039
Received: 22 September 2016 / Revised: 15 December 2016 / Accepted: 20 December 2016 / Published: 26 December 2016
PDF Full-text (1423 KB) | HTML Full-text | XML Full-text
Abstract
Smart grids have been introduced to replace conventional power distribution systems without real time monitoring for accommodating the future market penetration of plug-in electric vehicles (PEVs). When a large number of PEVs require simultaneous battery charging, charging coordination techniques have become one of
[...] Read more.
Smart grids have been introduced to replace conventional power distribution systems without real time monitoring for accommodating the future market penetration of plug-in electric vehicles (PEVs). When a large number of PEVs require simultaneous battery charging, charging coordination techniques have become one of the most critical factors to optimize the PEV charging performance and the conventional distribution system. In this case, considerable computational complexity of a central controller and exchange of real time information among PEVs may occur. To alleviate these problems, a novel threshold-based random charging (TBRC) operation for a decentralized charging system is proposed. Using PEV charging thresholds and random access rates, the PEVs themselves can participate in the charging requests. As PEVs with a high battery state do not transmit the charging requests to the central controller, the complexity of the central controller decreases due to the reduction of the charging requests. In addition, both the charging threshold and the random access rate are statistically calculated based on the average of supply power of the PEV charging system that do not require a real time update. By using the proposed TBRC with a tolerable PEV charging degradation, a 51% reduction of the PEV charging requests is achieved. Full article
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Open AccessArticle Non-Uniform Microstrip Antenna Array for DSRC in Single-Lane Structures
Sensors 2016, 16(12), 2101; doi:10.3390/s16122101
Received: 6 September 2016 / Revised: 29 November 2016 / Accepted: 6 December 2016 / Published: 11 December 2016
PDF Full-text (6733 KB) | HTML Full-text | XML Full-text
Abstract
Vehicular communications have been subject to a great development in recent years, with multiple applications, such as electronic payments, improving the convenience and comfort of drivers. Its communication network is supported by dedicated short range communications (DSRC), a system composed of onboard units
[...] Read more.
Vehicular communications have been subject to a great development in recent years, with multiple applications, such as electronic payments, improving the convenience and comfort of drivers. Its communication network is supported by dedicated short range communications (DSRC), a system composed of onboard units (OBU) and roadside units (RSU). A recently conceived different set-up for the tolling infrastructures consists of placing them in highway access roads, allowing a number of benefits over common gateway infrastructures, divided into several lanes and using complex systems. This paper presents an antenna array whose characteristics are according to the DSRC standards. Additionally, the array holds an innovative radiation pattern adjusted to the new approach requirements, with an almost uniform wide beamwidth along the road width, negligible side lobes, and operating in a significant bandwidth. Full article
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Open AccessArticle Traffic Management for Emergency Vehicle Priority Based on Visual Sensing
Sensors 2016, 16(11), 1892; doi:10.3390/s16111892
Received: 16 August 2016 / Revised: 12 October 2016 / Accepted: 25 October 2016 / Published: 10 November 2016
Cited by 2 | PDF Full-text (4121 KB) | HTML Full-text | XML Full-text
Abstract
Vehicular traffic is endlessly increasing everywhere in the world and can cause terrible traffic congestion at intersections. Most of the traffic lights today feature a fixed green light sequence, therefore the green light sequence is determined without taking the presence of the emergency
[...] Read more.
Vehicular traffic is endlessly increasing everywhere in the world and can cause terrible traffic congestion at intersections. Most of the traffic lights today feature a fixed green light sequence, therefore the green light sequence is determined without taking the presence of the emergency vehicles into account. Therefore, emergency vehicles such as ambulances, police cars, fire engines, etc. stuck in a traffic jam and delayed in reaching their destination can lead to loss of property and valuable lives. This paper presents an approach to schedule emergency vehicles in traffic. The approach combines the measurement of the distance between the emergency vehicle and an intersection using visual sensing methods, vehicle counting and time sensitive alert transmission within the sensor network. The distance between the emergency vehicle and the intersection is calculated for comparison using Euclidean distance, Manhattan distance and Canberra distance techniques. The experimental results have shown that the Euclidean distance outperforms other distance measurement techniques. Along with visual sensing techniques to collect emergency vehicle information, it is very important to have a Medium Access Control (MAC) protocol to deliver the emergency vehicle information to the Traffic Management Center (TMC) with less delay. Then only the emergency vehicle is quickly served and can reach the destination in time. In this paper, we have also investigated the MAC layer in WSNs to prioritize the emergency vehicle data and to reduce the transmission delay for emergency messages. We have modified the medium access procedure used in standard IEEE 802.11p with PE-MAC protocol, which is a new back off selection and contention window adjustment scheme to achieve low broadcast delay for emergency messages. A VANET model for the UTMS is developed and simulated in NS-2. The performance of the standard IEEE 802.11p and the proposed PE-MAC is analysed in detail. The NS-2 simulation results have shown that the PE-MAC outperforms the IEEE 802.11p in terms of average end-to-end delay, throughput and energy consumption. The performance evaluation results have proven that the proposed PE-MAC prioritizes the emergency vehicle data and delivers the emergency messages to the TMC with less delay compared to the IEEE 802.11p. The transmission delay of the proposed PE-MAC is also compared with the standard IEEE 802.15.4, and Enhanced Back-off Selection scheme for IEEE 802.15.4 protocol [EBSS, an existing protocol to ensure fast transmission of the detected events on the road towards the TMC] and the comparative results have proven the effectiveness of the PE-MAC over them. Furthermore, this research work will provide an insight into the design of an intelligent urban traffic management system for the effective management of emergency vehicles and will help to save lives and property. Full article
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Open AccessArticle Traffic Vehicle Counting in Jam Flow Conditions Using Low-Cost and Energy-Efficient Wireless Magnetic Sensors
Sensors 2016, 16(11), 1868; doi:10.3390/s16111868
Received: 9 August 2016 / Revised: 2 November 2016 / Accepted: 3 November 2016 / Published: 6 November 2016
Cited by 1 | PDF Full-text (4057 KB) | HTML Full-text | XML Full-text
Abstract
The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic
[...] Read more.
The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been worthwhile. A low-cost and energy-efficient type of multi-function wireless traffic magnetic sensor was designed and developed. Several advantages of the traffic magnetic sensor are that it is suitable for large-scale deployment and time-sustainable detection for traffic information acquisition. Based on the traffic magnetic sensor, a basic vehicle detection algorithm (DWVDA) with less computational complexity was introduced for vehicle counting in low traffic volume conditions. To improve the detection performance in jam flow conditions with a “tailgating effect” between front vehicles and rear vehicles, an improved vehicle detection algorithm (SA-DWVDA) was proposed and applied in field traffic environments. By deploying traffic magnetic sensor nodes in field traffic scenarios, two field experiments were conducted to test and verify the DWVDA and the SA-DWVDA algorithms. The experimental results have shown that both DWVDA and the SA-DWVDA algorithms yield a satisfactory performance in low traffic volume conditions (scenario I) and both of their mean absolute percent errors are less than 1% in this scenario. However, for jam flow conditions with heavy traffic volumes (scenario II), the SA-DWVDA was proven to achieve better results, and the mean absolute percent error of the SA-DWVDA is 2.54% with corresponding results of the DWVDA 7.07%. The results conclude that the proposed SA-DWVDA can implement efficient and accurate vehicle detection in jam flow conditions and can be employed in field traffic environments. Full article
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Open AccessArticle Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks
Sensors 2016, 16(11), 1834; doi:10.3390/s16111834
Received: 15 August 2016 / Revised: 23 October 2016 / Accepted: 24 October 2016 / Published: 1 November 2016
Cited by 3 | PDF Full-text (578 KB) | HTML Full-text | XML Full-text
Abstract
Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been
[...] Read more.
Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well. Full article
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Open AccessArticle A Cooperative Downloading Method for VANET Using Distributed Fountain Code
Sensors 2016, 16(10), 1685; doi:10.3390/s16101685
Received: 30 May 2016 / Revised: 21 August 2016 / Accepted: 26 September 2016 / Published: 12 October 2016
PDF Full-text (2551 KB) | HTML Full-text | XML Full-text
Abstract
Cooperative downloading is one of the effective methods to improve the amount of downloaded data in vehicular ad hoc networking (VANET). However, the poor channel quality and short encounter time bring about a high packet loss rate, which decreases transmission efficiency and fails
[...] Read more.
Cooperative downloading is one of the effective methods to improve the amount of downloaded data in vehicular ad hoc networking (VANET). However, the poor channel quality and short encounter time bring about a high packet loss rate, which decreases transmission efficiency and fails to satisfy the requirement of high quality of service (QoS) for some applications. Digital fountain code (DFC) can be utilized in the field of wireless communication to increase transmission efficiency. For cooperative forwarding, however, processing delay from frequent coding and decoding as well as single feedback mechanism using DFC cannot adapt to the environment of VANET. In this paper, a cooperative downloading method for VANET using concatenated DFC is proposed to solve the problems above. The source vehicle and cooperative vehicles encodes the raw data using hierarchical fountain code before they send to the client directly or indirectly. Although some packets may be lost, the client can recover the raw data, so long as it receives enough encoded packets. The method avoids data retransmission due to packet loss. Furthermore, the concatenated feedback mechanism in the method reduces the transmission delay effectively. Simulation results indicate the benefits of the proposed scheme in terms of increasing amount of downloaded data and data receiving rate. Full article
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Open AccessArticle Querying and Extracting Timeline Information from Road Traffic Sensor Data
Sensors 2016, 16(9), 1340; doi:10.3390/s16091340
Received: 16 June 2016 / Revised: 28 July 2016 / Accepted: 15 August 2016 / Published: 23 August 2016
Cited by 3 | PDF Full-text (2530 KB) | HTML Full-text | XML Full-text
Abstract
The escalation of traffic congestion in urban cities has urged many countries to use intelligent transportation system (ITS) centers to collect historical traffic sensor data from multiple heterogeneous sources. By analyzing historical traffic data, we can obtain valuable insights into traffic behavior. Many
[...] Read more.
The escalation of traffic congestion in urban cities has urged many countries to use intelligent transportation system (ITS) centers to collect historical traffic sensor data from multiple heterogeneous sources. By analyzing historical traffic data, we can obtain valuable insights into traffic behavior. Many existing applications have been proposed with limited analysis results because of the inability to cope with several types of analytical queries. In this paper, we propose the QET (querying and extracting timeline information) system—a novel analytical query processing method based on a timeline model for road traffic sensor data. To address query performance, we build a TQ-index (timeline query-index) that exploits spatio-temporal features of timeline modeling. We also propose an intuitive timeline visualization method to display congestion events obtained from specified query parameters. In addition, we demonstrate the benefit of our system through a performance evaluation using a Busan ITS dataset and a Seattle freeway dataset. Full article
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