Virtual Driver Research Articles

Modifying Guest OS to Optimize I/O Virtualization in KVM

There are some operations in Guest OS causing the I/O performance degradation.For it is the general OS,which is oriented physical machines,directly running on the virtual machine as the Guest OS.This paper evaluates KVM I/O performance,find that the Guest OS should be adapted to the virtual environment for better performance,and proposes some optimizations.First,reduce VM Exits by merging successive I/O instructions and decreasing the frequency of timer interrupt;Second,removes some redundant operations from Guest OS,including the operations useless in virtual environment,the I/O scheduler whose results will be rescheduled in the Host OS,and the NAPI support in virtual NIC driver.

Computational Steering and Parallel Online Monitoring Using RMA through the HDF5 DSM Virtual File Driver

Abstract As systems provide more resources and host an indefinitely growing number of cores, the amount of data produced by simulation codes is steadily increasing, creating a bottleneck at the point where the data must be transferred to post processing software. One solution is to avoid the use of a file system altogether and couple post processing software directly to the simulation using an interface common to both sides of the transfer. HDF5, the widely known IO library, offers a modular mapping of file contents to storage, allowing the user to use different methods (drivers) for reading and writing data. These drivers are organized in a Virtual File Layer (VFL) so that the user can easily switch between – and if necessary – extend them. In order to be able to visualize and analyze data in-situ, we developed a parallel virtual file driver called the DSM driver, which allows the transfer of data in parallel between two different codes using only the HDF5 API; this driver has now been extended to support remote memory access operations. Whilst the original implementation allows one to post-process data in-situ, we present in this paper extensions to the driver that provide the ability to couple parallel applications bidirectionally. We use this to perform computational steering of simulations. Commands and data are sent back to the simulation using either the driver layer itself (primarily commands) or the HDF5 layer via the DSM driver (datasets). The use of HDF5 datasets for transfer between codes makes true parallel coupling possible, even when the data models of the codes are not directly compatible. The steering interface presented here is shown implemented within ParaView, the parallel visualization application, but the API is generic and in fact any applications that make use of HDF5 may be connected using the driver.

Integrating Physical and Cognitive Human Models to Represent Driving Behavior

This research addresses the divide between cognitive and physical human models by integrating a cognitive human model with a physical human model. This new combined model uses the advantages of each type of model to overcome the weaknesses of the other. The capabilities of the new integrated model are evaluated in terms of modeling a task scenario with both cognitive and physical components: driving while performing a secondary in-vehicle task. The result is the Virtual Driver model.

Security enhanced virtual disk encryption system and technology

The authors studied and improved the transparent encryption and decryption program of virtual disk encryption software,using technology of file system filter driver and methods of auditing,preventing U disk proliferation and cache leakage. A file system filter driver layer was attached to the virtual driver layer in the program of virtual disk encryption. Test results in Truecrypt under various versions of Windows operation system show that problems of U disk proliferation and cache leakage can be avoided when the security layer is attached onto the virtual disk encryption software,and users' operations can also be monitored and audited. The results indicate that the security layer can effectively enhance security performance of the virtual disk encryption software.

Improving roll stability of articulated heavy vehicles using active semi-trailer steering

This paper discusses an optimal linear quadratic control algorithm to improve the roll stability of a tractor semi-trailer using active semi-trailer steering. The controller minimises a combination of the path-tracking deviation of the trailer rear end relative to the path of the hitch point (5th wheel) and the lateral acceleration of trailer centre of gravity (CoG). First a linear vehicle model of tractor semi-trailer is constructed. Then a ‘virtual driver’ model for trailer steering control is introduced to minimise the path-tracking deviation of trailer rear end. The lateral acceleration of trailer CoG is included as a second objective of the optimal controller so as to improve roll stability. A Kalman filter with linear vehicle model is used to estimate unknown vehicle states, needed by the controller. Simulation results show that optimal control of semi-trailer steering could improve the roll stability significantly during transient manoeuvres while keeping the path-tracking deviation of trailer rear end within an acceptable range.

Object-oriented modelling and simulation of a motorcycle

The design of a control oriented motorcycle model for the simulation of two-wheeled vehicles is widely recognized to be a very challenging task, as a complete analytical model is not directly available, due to its complexity and its high sensitivity to parameters' variations. Accordingly, a reliable model should be based on multibody modelling tools endowed with automated symbolic manipulation capabilities. This paper presents a simulation model for the dynamic behaviour of a motorcycle based on the object-oriented modelling paradigm developed in Modelica, within the Dymola environment. Specifically, we illustrate the modular approach to motorcycle modelling and discuss the tire-road interaction model, which is the crucial part of the proposed model. The validity of the proposed simulation model is assessed on real data, measured on an instrumented test vehicle. Further, to perform the verification phase a virtual driver model has been implemented, which allows to track both a roll angle and a target speed profile during different maneuvers. In particular, the behaviour of the driver is modelled as an inverse pendulum, with a rotational degree of freedom along the forward axis. This allows accounting for the driver lean angle, which is necessary to fully capture the real driving behaviour and its effects on the overall vehicle dynamics.

Study on modelling obstacles-avoidance behaviour of virtual driver based on multilayer fuzzy neural network

In virtual traffic scene of driving simulator, a fuzzy neural network controller Vision Fuzzy Back Propagation (VFBP) for modelling human-like driving obstacle-avoidance behaviour was developed. The obstacle-avoidance behaviour of virtual driver is inspired by the vision information based on real driving behaviour characteristic. VFBP controller consists of six layers. Considering the influence of the vehicle speed on the fuzzy distance, behaviour confidence and award coefficient are used to optimise fuzzy rules. Assessing level is used to ensure behaviour security. Adventure coefficient is used to call VFBP controller. In addition, VFBP controller can avoid the local smallest problem of the potential method, which makes the virtual vehicle go more smoothly. VFBP controller can simulate individual driver's behaviour through VFBP online learning.

A virtual motorcycle driver for closed-loop simulation

The development of a motorcycle driver for virtual prototyping applications is discussed. The driver is delivered with a commercial multibody code as a tool for performing closed-loop maneuvers with virtual motorcycle models. The closed-loop controller is developed with a qualitative analysis of how a human rider controls a motorcycle. The analysis concerns handling and maneuverability, which are relevant for real and virtual vehicle performance evaluation. A motorcycle model for control design and a controller structure are developed. The model is based on a mathematical representation of common-sense rules of motorcycle riding. The virtual rider is then tested in various operating conditions to assess whether the control requirements are achieved. Criteria for evaluating driver models are briefly discussed

A study on the factors that improve the velocity perception of a virtual reality‐based vehicle simulator

The Virtual Reality (VR) system of a real‐time VR‐linked vehicle simulator that was used in this study provides visual information and sound effects to participants. The VR system of a VR‐linked vehicle simulator should provide a perceived velocity similar with the perceived velocity in actual driving. To achieve these goals, modeling and rendering methods that offer an improved performance for complex VR applications, such as the 3D road model, were implemented and evaluated. We also evaluated the influences of graphic and engine sound effects on the driver and analyzed each result according to a driver's viewpoint, the dot densities of road texture provided, the lateral distance between a virtual driver and environmental objects, and the engine sound. Each factor was individually analyzed through an experiment that evaluated the influence of visual images or sound effects in the vehicle simulator. Through the experimental evaluation, the research results could be used for improving the effectiveness of VR‐based vehicle simulators.

Driving-Bots with a Neuroevolved Brain: Screaming Racers

The Videogame Industry of today is now just as strong as, and generates similar revenues to the Film Industry. Computer Games are distributed throughout the world and are sold to millions of people. Of the many different types of games, one of the most popular genres is car racing. Developers of this type of game are increasingly improving their Artificial Intelligence Systems so that their virtual drivers can exhibit Human-Level behaviours, and even higher. In this paper we show how these virtual drivers can be generically evolved using Neuroevolution, so obtaining several, distinct driving-bots with an increasing level of performance. These driving-bots can then be used as virtual opponents for different racing games, saving time and money in the development of a realistic AI System. To train our driving-bots and to test their performance we have developed Screaming Racers, a simple car-racing online videogame.

A Control Strategy for Vehicle Trajectory Tracking Using Multibody Models

The development of a virtual driver for a vehicle running in a given track constitutes an important application of vehicle dynamics. For this work a multibody based methodology for the design of a vehicle virtual driver is proposed. A simplified control model for the vehicle, which makes use of extended bicycle model, is implemented. The outcome of the controller based on the bicycle model is used to control a detailed multibody model of the real vehicle, including all suspension elements and tire/road forces, which provide the observed motion. The only variables that the control acts upon are the steering wheel angle and vehicle wheels' torques, which represent the traction and braking. The reference trajectory that has to be followed by the vehicle is defined by using a spline curve that represents its geometry. This description of the trajectory may be as complex as required by any particular application. The control model is implemented in the MATLAB environment while for the vehicle multibody model a stand alone multibody computer code is used. These two computational environments are interfaced using the available MATLAB communication functions. The virtual driver model is finally demonstrated for a sports vehicle that runs in prescribed track and the simulation results are discussed in face of the methods used.

Visual perception modelling for intelligent virtual driver agents in synthetic driving simulation

This paper introduces a vision model used within a synthetic (or purely software-based) driving simulation framework. This framework represents driver decision-making, individual vehicle movement and emergent traffic flow, and is intended to aid the integration of driver psychology, traffic management and vehicle engineering. The aims of developing the vision model discussed here are twofold: Firstly, to remove the unrealistic availability of ‘perfect knowledge’ concerning the positions and velocities of vehicles in a simulation and secondly, to provide a means of introducing deeper cognitive models of driver reasoning and behaviour. The paper presents the essential mechanisms of the vision model, along with the results of initial validation experiments conducted with Leicestershire Constabulary, Traffic Division in the UK. In these experiments, subjects' visual perception of positions and speeds of moving vehicles were measured and compared with estimations of the agent based driving simulator. The results have demonstrated the feasibility of modelling driver vision within an agent based traffic simulation using concepts derived from AI and ALife systems. The paper is completed by a short discussion on the future development of cognitive models enabled through more detailed vision modelling.

The driver as a sensor for crosswind sensitivity

There are currently no standardized criteria for evaluating a vehicle’s crosswind behaviour. The application of conventional criteria to some vehicles results in different — and in some cases even contradictory — evaluations. The Research Institute of Automotive Engineering and Vehicle Engines Stuttgart (FKFS) of Stuttgart University is developing an approach that uses the driver as a sensor, making use of the fact that the driver adapts his steering actions in accordance with the vehicle’s behaviour. The driver’s subjective assessment of the vehicle’s crosswind behaviour is thus derived from the way in which he adapts his steering actions. The investigations are aimed at modelling an adaptive, virtual driver for the purpose of analyzing the vehicle’s crosswind behaviour even in the vehicle development stage.

Monitoring Tool for Performance Measurements of Windows Nt-Based Lans

The increasing popularity of the Windows NT operating system has led to many companies and institutions installing Windows NT-based local area networks (LANs). These new Windows-NT based LANs have to be monitored continuously to determine their operating and performance parameters. At present, not many monitoring tools are available for the NT platform. In this article, some of the existing commercially available monitoring tools are discussed. After their drawbacks are identified, a new monitoring tool is developed using virtual device drivers. The developed tool is tested on a small network setup to demonstrate the various advantages.

OS7 交通安全における人間・機械系の視点

Traffic safety is a very important society problem. In order to solve this problem, we can investigate the traffic accident from three sides of the car, the traffic environment and human. This paper addresses a new study approach of traffic safety from the viewpoint of man-machine system. The investigation of the human mechanism on visual and auditory interactive information processing is very important for safe uses of multimedia machines and driver. In this study, (1) human characteristics of the audio-visual information processing are investigated by functional magnetic resonance imaging (fMRI), (2) a virtual driver system and (3) a portable eyesight test system are proposed.

Test bed for vehicle longitudinal control using chassis dynamometer and virtual reality: An application to adaptive cruise control

In this study, a test bed for vehicle longitudinal control is developed using a chassis dynamometer and real time 3-D graphics. The proposed test bed system consist of a chassis dynamometer on which test vehicle can run longitudinally, a video system that shows virtual driver view, and computer that control the test vehicle and realize the real time 3-D graphics. The purpose of the proposed system is to test vehicle longitudinal control and warning algorithms such as Adaptive Cruise Control (ACC), stop and go systems, and collision warning systems. For acceleration and deceleration situations which only need throttle movements, a vehicle longitudinal spacing control algorithm has been tested on the test bed. The spacing control algorithm has been designed based on sliding mode control and road grade estimation scheme which utilizes the vehicle engine torque map and gear shift information.