Effect of inter-vehicle communication on rear-end collision avoidance

This paper presents a probabilistic decision-making framework for rear-end collision avoidance systems, focusing on modeling the impact of major collision-causing factors on the occurrence of accidents. Decisions on when and how to assist drivers are made using a Bayesian network approach according to collision risk evaluation results, given a prior probabilistic knowledge. The structure of the Bayesian network model is learnt using a K2 algorithm with a practical dataset. To provide adequate response time for drivers, we also predict collision probability in the next monitoring interval using a Kalman filter model. The prediction accuracy is evaluated with different use cases and compared to real scenarios with the obtained dataset. To make our framework more relevant to practical applications, we also discuss the corresponding safety control strategies by classifying collision risk into high and low levels. In addition, the proposed model is evaluated through experiments including simulations and road tests. In the simulations, the algorithms are tested in different scenarios with various configurations of weather conditions, driver response capability, and vehicular dynamics. In order to demonstrate collision avoidance performance, the proposed model is also compared to existing schemes. In the road tests, the algorithm is embedded into an unmanned vehicle with predefined parameters to evaluate the impact of computational complexity on rear-end collision avoidance. Numerical results show that the proposed model provides an accurate estimation for car-following collision risk with a relatively low complexity, taking into account the impacts of vehicle dynamics, driver reaction capacity, and external environment on rear-end collisions.

We propose a new way to disperse planning route of transportation using IVC (Inter Vehicle Communication) in this paper. VICS (Vehicle Information and Communication System) has been developed to solve the traffic jam which is one of the ITS (Intelligent Transportation Systems) technologies. The VlCS is able to provide real-time global information with drivers and navigation system which helps drivers to find the fastest route according to the current traffic conditions. However, it is afraid that spatial oscillation of traffic jam "hunting phenomena" will happen if most of cars follow given global information with time delay from VICS. 0n the other hand, IVC is a developing technology which enables cars to exchange various information with others by optical communication, millimeter electromagnetic waves and so on. We therefore propose the combination way to decrease traffic congestion using IVC and VICS. At first we show the hunting phenomena in numerical simulations and the relationship between hunting phenomena and VICS user ratio. We propose a way to disperse planning route by IVC, and then confirm effect of the proposed way in city traffic models in numerical simulations.

ABSTRACTThis paper proposes a new safety system named emergency steering assist (ESA), which consists of the autonomous steering subsystem and differential braking subsystem. The control system is developed to mediate the conflict objectives of vehicle stabilisation and rear-end collision avoidance in highway driving. Instead of predefining a collision-free trajectory in the entire process of collision avoidance, the process of collision avoidance is divided into two stages. In stage 1, where the vehicle is guided to enter the adjacent lane with a constant centripetal acceleration to avoid collision, the steering manoeuvre is determined by the feedforward controller based on the steering dynamics. In stage 2, where the vehicle is guided along the centreline of the adjacent lane, the steering manoeuvre is determined by the controller based on the theory of model predictive control. In addition, the differential braking subsystem is designed with a comprehensive treatment to the requirements of collision avoidance and vehicle stabilisation. Finally, the simulation results demonstrate that the proposed ESA system can effectively achieve better balance between an emergency collision avoidance manoeuvre and vehicle stabilisation at high speeds in different conditions. The hardware-in-the-loop experiment developed by the authors is used to validate the real-time performance and effectiveness of the proposed control scheme.

In this paper, we want to present a parallel between the match effort (in an official match) and the training effort for senior national rugby teams. For monitoring the players, we used the Catapult Sport GPS system. This consists of a GPS which is well placed in a special pocket of each player’s shirt. The pocket is placed in the cervical area to diminish the possibility of injuries as much as possible. With the help of this equipment (together with a dedicated piece of software), there are determined for each player three speed levels (0-15 km/h, 15-21 km/h and above 21 km/h), the distances run, the maximum and minimum pulse values, the maximum speed, the number of accelerations, the distance run at a speed higher than 21 km/h, the total number of collisions and the number of rough collisions (higher than 5G); by subtracting these ones, we get the number of moderate collisions. Also, the equipment’s software can calculate the subjects’ metabolic rates. Having in mind that we are the first possessors of such equipment, we want to use it in order to obtain objective information about each subject, with the purpose of achieving a correlation between the training effort and the match effort for each position and for the entire team.

ABSTRACTRugby League (RL) is a high-impact collision sport characterised by repeated sprints and numerous high-speed impacts and consequently players often report immediate and prolonged muscle soreness in the days after a match. We examined muscle soreness after matches during a full season to understand the extent to which match characteristics influence soreness. Thirty-one elite Super League players provided daily measures of muscle soreness after each of the 26 competitive fixtures of the 2012 season. Playing position, phase of the season, playing surface and match characteristics were recorded from each match. Muscle soreness peaked at day 1 and was still apparent at day 4 post-game with no attenuation in the magnitude of muscle soreness over the course of the season. Neither playing position, phase of season or playing surface had any effects on the extent of muscle soreness. Playing time and total number of collisions were significantly correlated with higher ratings of muscle soreness, especially in the forwards. These data indicate the absence “contact adaptations” in elite rugby players with soreness present throughout the entire season. Strategies must now be implemented to deal with the physical and psychological consequences of prolonged feeling of pain.

Supersingular isogeny-based cryptosystems are considered an attractive candidate for the post-quantum cryptographic world due to their smaller key sizes. Based on the traversal in a supersingular isogeny graph (expander graph), Charles, Goren, and Lauter proposed a cryptographic hash function also known as CGL hash. In this paper, we present our study on the implementation-related aspects of the compact variation of the standard CGL hash function using different forms of elliptic curves (Weierstrass, Montgomery, and Legendre). Moreover, we show that some redundant computations in the original propositions of the CGL hash function can be avoided by utilizing the unique characteristics of the different forms of the elliptic curve. We also compared the running time and the total number of collisions through the experiments with the implemented algorithms.KeywordsPost-quantum cryptographySupersingular isogenyHashCGLElliptic curvesWeierstrassMontgomeryLegendre

Dedicated short range communication (DSRC) in the 5.9 GHz band has been considered as the main inter- vehicle communication (IVC) method in the past. Recently, IVC by cellular V2X (LTE support for V2X services) has attracted much attention, which includes two schemes: sidelink by which vehicles communicate directly with each other and broadcast via eNodeB for dissemination to farther vehicles. In this paper, we will show that none of these methods alone can fulfill the reliable and low delay communication, and investigate a basic method that combines DSRC for fast dissemination in a short distance and cellular V2X (broadcast via eNodeB) for reliable dissemination in a wide range. We notice that vehicles near the same event (e.g., falling object) may repeatedly disseminate the same message and some messages may be disseminated beyond their required range, which degrade network performance. Therefore, we further improve the efficiency of the basic method from two aspects: (i) dissemination range control that constrains the dissemination of each message within its required range, and (ii) duplicate dissemination control that avoids disseminating the message containing the same information in the network. Simulations on network simulator with LTE release-14 confirm that the method combining DSRC and cellular V2X reduces the delay by up to 66% compared to the method using only cellular V2X, and the extended method further improves the reachability by up to 15%.

Many threat assessment algorithms are based on a collection of threshold equations that predict when a collision is to occur. The fact that there are numerous algorithms suggests a need to understand the underlying principles behind the equation design and threshold settings. In this paper, we present a methodology to develop appropriate alerting thresholds based on performance metrics. This also allows us to compare different alerting algorithms. The method is a performance-based approach in state-space. and can thus be utilized in conjunction with any chosen alerting algorithm or sensor system. Using carefully prescribed trajectory models (which may include uncertainties), the performance tradeoff with and without an alert can be predicted for different states along the course of an encounter situation. This information can then be used to set appropriate threshold values for the desired alerting logic. The development of the threshold criteria for a rear-end collision warning system is given as an example. Though the approach given is presented as a threshold design tool, the methodology is self-contained as a threat assessment logic. The possibility exists to compute the performance measures on-the-fly from which alerting decisions can be made directly.

We developed the WACNet (wireless ad hoc community network) test system based on IEEE 802.11g and ESPAR antenna. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets at the communication situation (Tx and Rx). We can choose the data transmission rate to be adaptive or fixed among the duration through 54 Mbps to 1 Mbps for the purpose of experiment. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to improve total throughput, total error rate and so on rather than the original protocol. In this paper, we show the structure and wireless communication characteristics and the performance of video streaming at multihop communication with camera and codec connected to WACNet test system on the mobile experimental cars for ITS inter vehicle communications

Modeling the process of information relay through inter-vehicle communication

Relative hydraulic resistance, shear rate, and pressure in a vascular network integrate the network's architecture via fluid flow, and determine vein dynamics, with a time delay, in the prototypical organism Physarum polycephalum.

In this paper, an autonomous cruising traffic flow simulator including medium access control (MAC) for inter-vehicle communications (IVC) is constructed and the contention schemes are compared by using this simulator. The pure-ALOHA, slotted-ALOHA, and non-persistent CSMA schemes are simulated. The results of simulation show that the non-persistent CSMA is superior to the ALOHA schemes. This superiority becomes stronger with increasing communicating vehicle density. Also, it is shown quantitatively that setting the range of carrier sensing to twice the communication range can reduce the ratio of hidden stations that have a bad influence on the performance of the non-persistent CSMA scheme. In addition, the capture ratio in the IVC is considered in the simulations, and the influence of the capture effect on the performance of each scheme is discussed.

Describes the technologies of cooperative driving with automated vehicles and intervehicle communications in the Demo 2000 cooperative driving. Cooperative driving, aiming at the compatibility of safety and efficiency of road traffic, means that automated vehicles drive by forming a flexible platoon over a couple of lanes with a short intervehicle distance while performing lane changing, merging, and leaving the platoon. The vehicles for the demonstration are equipped with automated lateral and longitudinal control functions with localization data by the differential global positioning system (DGPS) and the intervehicle communication function with 5.8-GHz dedicated short range communication (DSRC) designed for the dedicated use in the demonstration. In order to show the feasibility and potential of the technologies, the demonstration was held in November 2000, on a test track with five automated vehicles. The scenario included stop and go, platooning, merging, and obstacle avoidance.

This paper reviews the expected wide and profound impact of nanotechnology for future wireless devices and communication technologies. This article points out the possibilities of overcoming the same problem set from a device perspective by taking advantage of the merits of nanotechnologies. At the same time, open research issues and challenges are identified to spark new interests and developments in this field. Devices that use wireless communication range from RFID tags to TV receivers, and satellites to mobile phones. The availability of internet access from tablets and mobile phones is growing at an exponential rate, causing increasing demands on the performance of wireless networks and mobile devices. Some passive components necessary in wireless devices, such as inductors and capacitors, cannot be minimized as quickly as transistors and integrated circuits. This imbalance makes it likely that the performance requirements of mobile handsets will exceed the capabilities of current RF technologies within the next 10 to 15 years. As well as the global growth in mobile internet access via tablets and smartphones, wireless sensors, health monitoring systems and other devices dependent on wireless communication are becoming more and more prevalent. Developing more compact, more efficient, and less expensive wireless communication devices will have significant impact on these areas and enable new solutions for healthcare services, logistics and environmental monitoring. The devices that use wireless communication ranges from RFID tags to television set receivers and satellites to mobile phones. The availability of internet access from mobile devices is growing at an exponential rate that causes rising demand on the wireless network and mobile devices' performance. As the type of activities that consumers are engaging in over the wireless connections is changing day in day out, it has been an increased need for the devices to change also. For instance in radios, the increasing quantity of mobile internet traffic there has been increased the need for additional frequency for support. The modern world is becoming an intelligent interactive environment that has needs novel autonomous sensors with wireless communication links that require to be incorporated into an everyday object. This is the reason why sensors that are nanoenabled integrated with small RF transceivers are useful in monitoring air quality, water pollution among other aspects. The main drivers of changing into nanotechnology in wireless devices are needed for high performance, reduced consumption of power as well as reduced compact size.

This article develops a new method of data-driven modeling for a class of multiple-transmitter single-receiver wireless power transfer (WPT) systems. A continuous-time multiple-input single-output (MISO) model with pure time delays is used to characterize the input–output behavior of the system, where the transfer functions associated with each input channel are not constrained to have the same denominator. Moreover, the time delays are allowed to be a fraction of the sampling interval in order to account for the delay effects that stem from circuit components and wireless communication, which are, by nature, often a fraction of the sampling interval. An optimal refined instrumental variable method is proposed to estimate the parameters and time delays of the MISO model based on sampled input–output data. In contrast to the conventional circuit-theory-based modeling methods that rely on circuit parameters and result in models which are often complex, the proposed data-based method yields parsimonious models, whose parameters are directly estimated from input–output data. Due to the easy availability of sampled data in control engineering applications, the proposed method is clearly more user-friendly, having a broad prospect for efficient operation of WPT systems, such as prediction, optimization, and control. Numerical and experimental results are presented to validate the effectiveness and merit of the proposed method.