http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2012, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/571683/As the environmental pollution and energy crises are getting more and more remarkable, hybrid electric vehicles (HEVs) have taken on an accelerated pace in the world. A comprehensive overview of HEVs is presented in this paper, with the emphasis on configurations, main issues, and energy management strategies. Conclusions are discussed finally.Caiying Shen, Peng Shan, and Tao GaoCopyright © 2011 Caiying Shen et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/934023/The integration of a flywheel as a power handling can increase the energy storage capacity and reduce the number of battery charge/discharge cycles. Furthermore, the ability of recovering energy of the vehicle during breaking can increase the system efficiency. The flywheel-based all-electric driveline investigated here has its novelty in the use of a double-wound flywheel motor/generator, which divides the system in two different voltage levels, enhancing the efficiency of the electric driveline. The connection of two AC electrical machines (i.e., the flywheel and the wheel motor) with different and variable operation frequency is challenging. A power matching control applied to an AC/DC/AC converter has been implemented. The AC/DC/AC converter regenerates the electric power converted during braking to the flywheel machine, used here as power handling device. By controlling the power balance, the same hardware can be used for acceleration and braking, providing the reduction of harmonics and robust response. A simulation of the complete system during braking mode has been performed both in Matlab and Simulink, and their results have been compared. The functionality of the proposed control has been shown and discussed, with full regeneration achieved. A round-trip efficiency (wheel to wheel) higher than 80% has been obtained.Janaína G. Oliveira, Johan Lundin, and Hans BernhoffCopyright © 2011 Janaína G. Oliveira et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/810273/With transport and traffic developing permanently, we can meet more and more aggressive drivers on roads. We can see various kinds of aggressiveness and aggressive behavior that can lead to dangerous situations which can threaten one's health or even life. The problem of aggressive driving on the roads is becoming more current. Speeding, inappropriate gestures, and nonobservance of safe distance, are only a fraction of the aggressive behavior of many drivers that need to be solved in the road traffic. At present, the problem of aggressive driver behavior in Slovakia is not resolved yet.Alica Kalašová and Zuzana KrchováCopyright © 2011 Alica Kalašová and Zuzana Krchová. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/326865/Considering automatic and effective stereo image matching for vehicle-borne mobile mapping system (VMMS), a new stereo image matching algorithm based on digital parallax model (DPM) is proposed in this paper. The new matching propagation strategy is designed in this algorithm, which includes two processes as DPM construction and parallax prediction. With some known matched points, the DPM of stereo image pairs is firstly constructed, and parameters for confirming conjugate epipolar line is also worked out. Then searching range during dense matching can be confirmed under constraints of DPM and epipolar line, which can improve matching speed and accuracy. Furthermore, to improve matching robustness, the computation model of similarity measurement combined with local structure feature and global color feature is designed. The new algorithm is applied to actual stereo images taken by VMMS to verify its validity. Experimental results show that the proposed approach has higher reliability and accuracy.Ka Zhang, Yehua Sheng, and Chun YeCopyright © 2011 Ka Zhang et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/120194/Vehicular networks are the major ingredients of the envisioned Intelligent Transportation Systems (ITS) concept. An important component of ITS which is currently attracting wider research focus is road traffic monitoring. The actual approaches for traffic road monitoring are characterized by longer response times and are also subject to higher processing requirements and possess high deployment costs. In this paper, we propose a completely distributed and scalable mechanism for wireless sensor network-based road traffic monitoring. The approach relies on the distributed and bidirectional exchange of traffic information between the vehicles traversing the routes and a miniature cluster head and takes into consideration both the security and reliability of data communication. In addition, the communication between nodes is collision-free since the underlined data link layer protocol relies on a heuristic time multiplexed-based protocol. The performance analysis shows that the proposed mechanism usually outperforms other algorithms for different traffic densities.M. MeriboutCopyright © 2011 M. Meribout. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/439074/We propose an approach for vehicle localization in dense urban environments using a stereoscopic system and a GPS sensor. Stereoscopic system is used to capture the stereo video flow, to recover the environments, and to estimate the vehicle motion based on feature detection, matching, and triangulation from every image pair. A relative depth constraint is applied to eliminate the tracking couples which are inconsistent with the vehicle ego-motion. Then the optimal rotation and translation between the current and the reference frames are computed using an RANSAC based minimization method. Meanwhile, GPS positions are obtained by an on-board GPS receiver and periodically used to adjust the vehicle orientations and positions estimated by stereovision. The proposed method is tested with two real sequences obtained by a GEM vehicle equipped with a stereoscopic system and a RTK-GPS receiver. The results show that the vision/GPS integrated trajectory can fit the ground truth better than the vision-only method, especially for the vehicle orientation. And vice-versa, the stereovision-based motion estimation method can correct the GPS signal failures (e.g., GPS jumps) due to multipath problem or other noises.Lijun Wei, Cindy Cappelle, Yassine Ruichek, and Frédérick ZannCopyright © 2011 Lijun Wei et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2011/275785/This paper presents a comparative study of outer rotor PMAC machine candidates for starter-generator application in hybrid bus with series power train configuration. PMAC machines with interior and surface mount permanent magnets are considered and compared, although a complete analysis is only carried out for the SPM. Different design aspects such as concentrated versus distributed windings as well as interior and exterior rotor structures are evaluated. Different slot numbers per pole per phase configurations for concentrated winding PMAC machines are also examined. Comparison and evaluation of the machines is based on their performance which included evaluation of winding and iron losses, magnet losses, and maximum torque capability as well as the size and weight of the machines.Sinisa Jurkovic and Elias G. StrangasCopyright © 2011 Sinisa Jurkovic and Elias G. Strangas. All rights reserved.http://www.hindawi.com/journals/ijvt/2010/238518/The FlexRay Transport Protocol (FrTp) is designed to support reliable and efficient communication between various computers embedded in vehicles. It uses a standardised FlexRay communication bus and introduces a go-back-N style retransmission algorithm. A formal modelling language, Coloured Petri nets (CPN), has been applied to verify the protocol design. Separate CPN models of the FrTp service and protocol are developed and with state space analysis-used to prove for selected configurations that FrTp is deadlock-free and conforms to the service specification when transferring a single-protocol data unit from sender to receiver. In addition, closed-form solutions relating the state space size, retransmission limit, and number of segments are found, giving increased confidence that FrTp is error-free, even for configurations where the state explosion problem arises.Steven Gordon and San ChoosangCopyright © 2010 Steven Gordon and San Choosang. All rights reserved.http://www.hindawi.com/journals/ijvt/2010/432762/The problem of resource allocation for the downlink of wireless systems operating over a frequency-selective channel is investigated. It is assumed that both the Base Station (BS) and each user are equipped with a single antenna (Single Input Single Output-SISO case), and Orthogonal Frequency Division Multiple Access (OFDMA) is used as a multiple access scheme. The aim is to maximize the sum of the users' data rates subject to constraints on total available power and proportional fairness among users' data rates. Achieving the optimal solution has a high computational cost thereby the use of suboptimal techniques is necessary. A suboptimal, but efficient, scheme is devised, and it is shown, via simulation, that not only the proposed resource allocation scheme achieve higher sum of the users' data rates than other existing schemes but also the sum data rate is distributed fairly and flexibly among users. In addition, the proposed scheme is complexity effective and can be applied to latest-generation wireless systems that provide Quality-of-Service (QoS) guarantees.Vasileios D. Papoutsis, Ioannis G. Fraimis, and Stavros A. KotsopoulosCopyright © 2010 Vasileios D. Papoutsis et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2010/893197/A Hybrid Pneumatic Power System (HPPS) has been developed for several years with the major aim of reducing the vehicle fuel consumption, environment pollution and enhancing the vehicle performance as well. Comparing with the conventional hybrid system, HPPS replaces the battery's electrochemical energy with a high-pressure air storage tank and enables the internal combustion engine (ICE) to function at its sweet spot. Besides, the HPPS, which effectively merges both the high-pressure air flow from the storage tank and the recycled exhaust flow from the ICE, thereby increases the thermal efficiency of the ICE and transforms the merged flow energy into mechanical energy using a high-efficiency turbine. This paper focuses on the major research process into HPPSs, including overall dynamic simulation and experimental validation. By using the simulation tool ITI-Sim, this research demonstrates an experiment which can be operated precisely according to the requirements of various driving conditions under which a car actually runs on the road in accordance with the regulated running vehicle test mode. HPPS is expected to increase the performance of the entire system from 15% to 39%, and is likely to replace the traditional system in the coming years.K. David Huang and Hoai-Nam NguyenCopyright © 2010 K. David Huang and Hoai-Nam Nguyen. All rights reserved.http://www.hindawi.com/journals/ijvt/2010/797405/The Dedicated Short-Range Communications (DSRC) standards suite is based on multiple cooperating standards mainly developed by the IEEE. In particular, we focus this paper on the core design aspects of DSRC which is called Wireless Access in Vehicular Environment (WAVE). WAVE is highlighted in IEEE 1609.1/.2/.3/.4. The DSRC and WAVE standards have been the center of major attention in both research and industrial communities. In 2008, WAVE standard was the third best seller standards in the history of the IEEE. This attention reflects the potential of WAVE to facilitate much of the vehicular safety applications. In this paper we present a fairly detailed tutorial of the WAVE standards. We extend the paper by describing some of the lessons learned from particular design approaches. We direct the reader to the landmark research papers in relevant topics. We alert the reader about major open research issues that might lead to future contribution to the WAVE design.Yasser L. MorganCopyright © 2010 Yasser L. Morgan. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/505246/The internal parameter of UNI 60 rail is calculated by using finite elements methods. Steel's characterizations by its normal magnetization curve and by complex magnetic permeability are here considered and included into the proposed FEM models. Rail's resistance and internal inductance in function of current and frequency are calculated using both FEM and analytical models. The results obtained at the frequency of 50 Hz are compared with few measurements available, and then they are extended to other frequencies.Alberto Dolara and Sonia LevaCopyright © 2009 Alberto Dolara and Sonia Leva. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/702346/Unlike sensor and other ad-hoc wireless networks, vehicular ad-hoc networks (VANETs) are characterized by its high mobility which allows a very short communication interval among onboard units (OBUs) and between an OBU and road-side units (RSUs). This major characterization motivates the design of communication protocols that are noninteractive or at least require a very limited number of rounds between units. The challenging issue is that such protocols must satisfy a number of security services that could be complex by their nature. In secure VANETs protocols, anonymity and traceability are two important services, yet, achieving a satisfactory security level for both of them—with acceptable complexity—is not an easy task due to the contradicting requirements: anonymous transmission must not be traceable by any individual while if a transmission is traceable, then anonymity is threatened. Existing secure VANETs protocols for anonymous and traceable transmissions either, provide unconditional anonymity where traceability and revocation are impossible, or grant trust to a thirdparty not to reveal the identity of a unit unless there is a legal reason. In this paper, we propose the first secure VANET protocol that allows authenticated transmission among OBUs and RSUs and at the same time enjoys the following properties. (i) The transmission among OBUs and RSUs is noninteractive (i.e., a one-move transmission without any interactive setup requirements). (ii) The authenticated transmission between any pair of units is anonymous (i.e., no single authority knows any information about the identity of the communicating OBU). (iii) In serious road crimes (e.g., hit-and-run, road rage, etc.) and under court order, an OBU could be traced to its clear identity. We also show how our protocol could be used to setup a confidential session between any pair of units without relying on extensive number of interactive rounds.Maged Hamada IbrahimCopyright © 2009 Maged Hamada Ibrahim. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/891367/This paper aims to study the performance of low complexity adaptive resource allocation in the downlink of OFDMA systems with fixed or variable rate requirements (with fairness consideration). Two suboptimal resource allocation algorithms are proposed using the simplifying assumption of transmit power over the entire bandwidth. The objective of the first algorithm is to maximize the total throughput while maintaining rate proportionality among the users. The proposed suboptimal algorithm prioritizes the user with the highest sensitivity to the subcarrier allocation, and the variance over the subchannel gains is used to define the sensitivity of each user. The second algorithm concerns rate adaptive resource allocation in multiuser systems with fixed rate constraints. We propose a suboptimal joint subchannel and power allocation algorithm which prioritizes the users with the highest required data rates. The main feature of this algorithm is its low complexity while achieving the rate requirements.Sanam Sadr, Alagan Anpalagan, and Kaamran RaahemifarCopyright © 2009 Sanam Sadr et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/423141/We propose to use IEEE 802.11e in conjunction with retransmission mechanisms for priority-based Intervehicle Communication (IVC) for highway safety messaging in both vehicular infrastructure and ad hoc networks. Each IVC message, which is assigned a priority based on the safety event urgency, requires different quality of service in terms of communication reliability and average delay. To increase the communication reliability in a broadcast-based IVC, we apply retransmission mechanisms that can provide proportional reliability differentiation for each prioritized message. We evaluate the performance of our proposed protocol using OPNET Modeler, in terms of percentage of successful transmissions and average delay. The protocol performance is evaluated for (1) different system parameters such as the packet size, number of vehicles, and percentage of priority 1 vehicles, and (2) priority-based protocol parameters, such as contention window, interframe spacing and retransmission parameters. The results show that proper protocol parameter settings per priority message result in an efficient solution for priority based broadcast IVC. Moreover, the proposed protocol is fully compatible with both IEEE 802.11 and IEEE 802.11e standards.Chakkaphong SuthaputchakunCopyright © 2009 Chakkaphong Suthaputchakun. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/958056/Physical carrier sensing has to date mainly been exploited for improving medium access control in wireless networks. Recently, a parallel algorithm striving to extensively exploit physical carrier sensing for constructing and maintaining a connected dominating set (CDS), which is also known as spanner, backbone, or overlay network in wireless ad hoc networks with interference ranges larger than transmission ranges has been proposed. Existing evaluations of this algorithm are limited to theoretical asymptotic bounds and simulations of static networks. In this paper, we evaluate the physical carrier sensing-based CDS maintenance for mobile ad hoc networks through discrete event simulations. For a wide range of node speeds and node densities, we evaluate the CDS characteristics and message exchanges required for maintaining the CDS. We find that the algorithm maintains a stable leader set dominating all nodes in the network for a wide range of mobility levels but struggles to maintain connectivity at high mobility levels. We also quantify the portions of the control messages for CDS maintenance that are exchanged through physical carrier sensing. We find that the parallel algorithm manages to greatly reduce the reliance on intact message receptions.Sapna Deval, Luke Ritchie, Martin Reisslein, and Andrea W. RichaCopyright © 2009 Sapna Deval et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/105363/Choosing various injection strategies and intake conditions are potentially effective techniques to reduce exhaust emission from diesel engines. The purpose of this study is to investigate the effect of different spray incoming angles, different spray cone angles, different injection timing, and different intake temperatures together with emission characteristics on a heavy duty diesel engine via three dimensional computational fluid dynamics (CFD) procedures. Furthermore the effect of multiple injector combustion chamber and its benefits in pollutant reduction is studied. The principal results show the significant differences in soot and NO generation during combustion between above different strategies.M. Gorji-Bandpy, S. Soleimani, and D. D. GanjiCopyright © 2009 M. Gorji-Bandpy et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2009/123231/The numerous benefits of real-time 3D awareness for autonomous vehicles have motivated the incorporation of stereo cameras to the perception units of intelligent vehicles. The availability of the distance between camera and objects is essential for such applications as automatic guidance and safeguarding; however, a poor estimation of the position of the objects in front of the vehicle can result in dangerous actions. There is an emphasis, therefore, in the design of perception engines that can make available a rich and reliable interval of ranges in front of the camera. The objective of this research is to develop a stereo head that is capable of capturing 3D information from two cameras simultaneously, sensing different, but complementary, fields of view. In order to do so, the concept of bifocal perception was defined and physically materialized in an experimental bifocal stereo camera. The assembled system was validated through field tests, and results showed that each stereo pair of the head excelled at a singular range interval. The fusion of both intervals led to a more faithful representation of reality.Francisco Rovira-Más, Qi Wang, and Qin ZhangCopyright © 2009 Francisco Rovira-Más et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2008/413821/Wireless local loop (WLL) provides reliable, flexible, and economical access to the local telephone service using radio technology in the place of traditional wireline. In this paper, an analytical model is derived to evaluate the effect of both imperfect power control and imperfect sectorization on the performance of code division multiple access (CDMA) WLL systems. The results show that the capacity degradation, due to imperfect power control, is about 25.8% and 11.5% for single cell and multiple cell systems, respectively. Increasing the overlapping angle from 0° to 5° causes the capacity gain to decrease from 6 to 5.53, while the corresponding sectorization efficiency drops from 100% to 92.3%.Sami A. El-DolilCopyright © 2008 Sami A. El-Dolil. All rights reserved.http://www.hindawi.com/journals/ijvt/2008/721386/A deterministic simulation model for the calculation of sojourn time statistics is proposed. The model is designed for urban cells taking into account city movement in street pattern, traffic lights, and crossings. Sojourn time and remaining sojourn time are assumed to be random variables that follow a gamma distribution. The parameters of gamma are found for a range of the chosen cell parameters (road length, probability of stopping at a crossing and cell radius) using Monte Carlo simulation. Then, the values are fitted to the empirical model using genetic algorithms with grammatical evolution. The model can be used to calculate sojourn time statistical parameters for any urban circular cell with square street pattern.Georgios S. Paschos, Ioannis G. Tsoulos, Efstathios D. Vagenas, Stavros A. Kotsopoulos, and George K. KaragiannidisCopyright © 2008 Georgios S. Paschos et al. All rights reserved.http://www.hindawi.com/journals/ijvt/2008/267513/Vehicular networks are sets of surface transportation systems that have the ability to communicate with each other. There are several possible network architectures to organize their in-vehicle computing systems. Potential schemes may include vehicle-to-vehicle ad hoc networks, wired backbone with wireless last hops, or hybrid architectures using vehicle-to-vehicle communications to augment roadside communication infrastructures. Some special properties of these networks, such as high mobility, network partitioning, and constrained topology, differentiate them from other types of wireless networks. We provide an in-depth discussion on the important studies related to architectural design and routing for such networks. Moreover, we discuss the major security concerns appearing in vehicular networks.Ioannis Broustis and Michalis FaloutsosCopyright © 2008 Ioannis Broustis and Michalis Faloutsos. All rights reserved.http://www.hindawi.com/journals/ijvt/2008/859571/This paper describes a fault-tolerant steer-by-wire road wheel control system. With dual motor and dual microcontroller architecture, this system has the capability to tolerate single-point failures without degrading the control system performance. The arbitration bus, mechanical arrangement of motors, and the developed control algorithm allow the system to reconfigure itself automatically in the event of a single-point fault, and assure a smooth reconfiguration process. Both simulation and experimental results illustrate the effectiveness of the proposed fault-tolerant control system.Bing Zheng and Sohel AnwarCopyright © 2008 Bing Zheng and Sohel Anwar. All rights reserved.