779 research outputs found

    The Research and Analysis for Rear View Transmission Based on IEEE 802.11 Wireless

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    [[abstract]]In recent years, because techniques of network communication have highly developed, the related applications has been used in many different area. IEEE 802.11 standard was formulated at 1997, and Wi-Fi alliance is formed in 1999. Today, IEEE 802.11 is the general standard in industry. In this paper, we use Wi-Fi as the interface in transmission to simulate that using the event data recorder with Wi-Fi interface to connect with the main center system and send the image to the screen in a car. Unlike the wired transmit solution, there is a problem that power consumption in wireless transmission. Therefore, we presented an algorithm to make the balance between efficiency and power consumption. We will explain that how to reduce the power consumption but keep real time reaction and make to optimization in following chapter.[[conferencetype]]國際[[conferencedate]]20140827~20140829[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]Kokura, Kyushu, Japa

    Design of dielectric resonator antenna arrays for wireless applications

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    This thesis presents design of dielectric resonator antenna array for wireless applications. Three antenna designed are presented in the following sections. The first design is a notched chamfered two element rectangular dielectric resonator antenna (DRA) array for wireless (WLAN and WIMAX) applications. Here the DRA array is excited by conformal patch connected to microstrip line. The shape is notched and chamfered to improve the performance of the antenna. From the Simulation results it can be observed that the proposed antenna covers 2.4, 3.6 and 5 GHz WLAN bands and 3.4 to 3.7 GHz WIMAX bands, achieving an impedance bandwidth from 2.18 to 3.75 GHz and 4.84 to 5.14 GHz. Parametric study is done by varying the shapes of the rectangular DRA arrays (Simple Rectangle, chamfered and chamfered with notched). Another parametric study is carried out by varying the dimension of the ground plane of the final design. The second design is a rectangular shaped two element Dielectric Resonator Antenna (DRA) array for 2.4 GHz WLAN application. Here microstrip feed line in corporate (parallel) arrangement is used for feeding. Simulation result shows that the antenna achieves a bandwidth from 2.1 to 3 GHz, covering the 2.4 GHz WLAN band. Here the parametric study is done by varying the feed line and the ground plane of the antenna. The simulation results as well as the parametric studies are incorporated in this thesis. The third one is the Design of four element rectangular shaped dielectric resonator antenna (RDRA) array for wireless applications. The RDRA array is fed by rectangular conformal patch (RCP) connected to microstrip line. Simulation result shows that the proposed antenna achieves an impedance bandwidth from 4 GHz to 7.1 GHz covering various wireless bands. Parametric studies have been carried out by varying the RCP height and the ground plane of the final design

    Development and Flight Testing of a Wireless Avionics Network Based on the IEEE 802.11 Protocols

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    This report describes the development and flight testing of the IEEE 802.11 protocol-based Wireless Flight Management System (WFMS) using low cost Commercial-Off-The-Shelf (COTS) equipment and software. The unlicensed spectrum allocation in the 2.4 GHz and 5 GHz bands by the FCC has encouraged the industry to develop new standards for short-range communication that are commercially viable. This has resulted in new short-range communication technologies like Bluetooth and the Wireless Local Area Network (WLAN). The new modulation techniques developed for wireless communication support wired equivalent data rates. The commercial success of these technologies and their wide market adaptation has resulted in reduced costs for the devices that support these technologies. Applications of wireless technology in aerospace engineering are vast, including development, testing, manufacturing, prognostics health management, ground support equipment and active control. The high data rates offered by technologies like WLAN (IEEE 802.11 a/b/g) are sufficient to implement critical and essential data applications of avionics systems. A wireless avionics network based on IEEE 802.11a/b/g protocols will reduce the complexity and cost of installation and maintenance of the avionics system when compared to the existing wired system. The proposed WFMS imitates the flight management system of any commercial aircraft in terms of functionality. It utilizes a radio frequency for the transmission of the sensor data to the Cockpit Display Unit (CDU) and the Flight Management Computer (FMC). WFMS consists of a FMC, data acquisition node, sensor node and a user interface node. The FMC and the data acquisition nodes are built using PC/104 standard modules. The sensor node consists of an Attitude and Heading Reference System (AHRS) and a GPS integrated with a serial device server. The user interface node is installed with moving map software which receives data from the AHRS and GPS to display flight information including topographic maps, attitude, heading, velocity, et cetera. This thesis demonstrates the performance evaluation of the WFMS both on the ground and in flight, and its advantages over a wired system. This thesis focuses on the evaluation of IEEE 802.11a/b/g protocols for avionics application. Efforts taken to calibrate the available bandwidth of the WLAN network at different operating conditions and varying ranges using different network analysis tools are explained briefly. Considerable research on issues like electromagnetic interference and network security critical to the development of a wireless network for avionics has also been done. This report covers different aspects of the implementation of wireless technology for aircraft systems. This work is a successful starting point for the new fly-by-wireless concept with extensions to active wireless flight control

    A survey on vehicular communication for cooperative truck platooning application

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    Platooning is an application where a group of vehicles move one after each other in close proximity, acting jointly as a single physical system. The scope of platooning is to improve safety, reduce fuel consumption, and increase road use efficiency. Even if conceived several decades ago as a concept, based on the new progress in automation and vehicular networking platooning has attracted particular attention in the latest years and is expected to become of common implementation in the next future, at least for trucks.The platoon system is the result of a combination of multiple disciplines, from transportation, to automation, to electronics, to telecommunications. In this survey, we consider the platooning, and more specifically the platooning of trucks, from the point of view of wireless communications. Wireless communications are indeed a key element, since they allow the information to propagate within the convoy with an almost negligible delay and really making all vehicles acting as one. Scope of this paper is to present a comprehensive survey on connected vehicles for the platooning application, starting with an overview of the projects that are driving the development of this technology, followed by a brief overview of the current and upcoming vehicular networking architecture and standards, by a review of the main open issues related to wireless communications applied to platooning, and a discussion of security threats and privacy concerns. The survey will conclude with a discussion of the main areas that we consider still open and that can drive future research directions.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

    Making Transport Safer: V2V-Based Automated Emergency Braking System

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    An important goal in the field of intelligent transportation systems (ITS) is to provide driving aids aimed at preventing accidents and reducing the number of traffic victims. The commonest traffic accidents in urban areas are due to sudden braking that demands a very fast response on the part of drivers. Attempts to solve this problem have motivated many ITS advances including the detection of the intention of surrounding cars using lasers, radars or cameras. However, this might not be enough to increase safety when there is a danger of collision. Vehicle to vehicle communications are needed to ensure that the other intentions of cars are also available. The article describes the development of a controller to perform an emergency stop via an electro-hydraulic braking system employed on dry asphalt. An original V2V communication scheme based on WiFi cards has been used for broadcasting positioning information to other vehicles. The reliability of the scheme has been theoretically analyzed to estimate its performance when the number of vehicles involved is much higher. This controller has been incorporated into the AUTOPIA program control for automatic cars. The system has been implemented in Citroën C3 Pluriel, and various tests were performed to evaluate its operation

    INTELLIGENTE TRANSPORT SYSTEMEN ITS EN VERKEERSVEILIGHEID

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    This report discusses Intelligent Transport Systems (ITS). This generic term is used for a broad range of information-, control- and electronic technology that can be integrated in the road infrastructure and the vehicles themselves, saving lives, time and money bymonitoring and managing traffic flows, reducing conges-tion, avoiding accidents, etc. Because this report was written in the scope of the Policy Research Centre Mobility & Public Works, track Traffic Safety, it focuses on ITS systems from the traffic safety point of view. Within the whole range of ITS systems, two categories can be distinguished: autonomous and cooperative systems. Autonomous systems are all forms of ITS which operate by itself, and do not depend on the cooperation with other vehicles or supporting infrastructure. Example applications are blind spot detection using radar, electronic stability control, dynamic traffic management using variable road signs, emergency call, etc. Cooperative systems are ITS systems based on communication and cooperation, both between vehicles as between vehicles and infrastructure. Example applications are alerting vehicles approaching a traffic jam, exchanging data regarding hazardous road conditions, extended electronic brake light, etc. In some cases, autonomous systems can evolve to autonomous cooperative systems. ISA (Intelligent Speed Adaptation) is an example of this: the dynamic aspect as well as communication with infrastructure (eg Traffic lights, Variable Message Sign (VMS)...) can provide additional road safety. This is the clear link between the two parts of this report. The many ITS applications are an indicator of the high expectations from the government, the academic world and the industry regarding the possibilities made possible by both categories of ITS systems. Therefore, the comprehensive discussion of both of them is the core of this report. The first part of the report covering the autonomous systems treats two aspects: 1. Overview of European projects related to mobility and in particular to road safety 2. Overview for guidelines for the evaluation of ITS projects. Out of the wide range of diverse (autonomous) ITS applications a selection is made; this selection is focused on E Safety Forum and PreVENT. Especially the PreVent research project is interesting because ITS-applications have led to a number of concrete demonstration vehicles that showed - in protected and unprotected surroundings- that these ITS-applications are already technically useful or could be developed into useful products. The component “guidelines for the evaluation of ITS projects” outlines that the government has to have specific evaluation tools if the government has the ambition of using ITS-applications for road safety. Two projects -guidelines for the evaluation of ITS projects- are examined; a third evaluation method is only mentioned because this description shows that a specific targeting of the government can be desirable : 1. TRACE describes the guidelines for the evaluation of ITS projects which are useful for the evaluation of specific ITS-applications. 2. FITS contains Finnish guidelines for the evaluation of ITS project; FIS is an adaptation of methods used for evaluation of transport projects. 3. The third evaluation method for the evaluation of ITS projects is developed in an ongoing European research project, eImpact. eImpact is important because, a specific consultation of stake holders shows that the social importance of some techniques is underestimated. These preliminary results show that an appropriate guiding role for the government could be important. In the second part of this document the cooperative systems are discussed in depth. These systems enable a large number of applications with an important social relevance, both on the level of the environment, mobility and traffic safety. Cooperative systems make it possible to warn drivers in time to avoid collisions (e.g. when approaching the tail of a traffic jam, or when a ghost driver is detected). Hazardous road conditions can be automatically communicated to other drivers (e.g. after the detection of black ice or an oil trail by the ESP). Navigation systems can receive detailed real-time up-dates about the current traffic situation and can take this into account when calculating their routes. When a traffic distortion occurs, traffic centers can immediately take action and can actively influence the way that the traffic will be diverted. Drivers can be notified well in advance about approaching emergency vehicles, and can be directed to yield way in a uniform manner. This is just a small selection from the large number of applications that are made possible because of cooperative ITS systems, but it is very obvious that these systems can make a significant positive contribution to traffic safety. In literature it is estimated that the decrease of accidents with injuries of fatalities will be between 20% and 50% . It is not suprising that ITS systems receive a lot of attention for the moment. On an international level, a number of standards are being established regarding this topic. The International Telecommunications Uniont (ITU), Institute for Electrical and Electronics Engineers (IEEE), International Organization for Standardization (ISO), Association of Radio Industries and Business (ARIB) and European committee for standardization (CEN) are currently defining standards that describe different aspects of ITS systems. One of the names that is mostly mentioned in literature is the ISO TC204/WG16 Communications Architecture for Land Mobile environment (CALM) standard. It describes a framework that enables transparent (both for the application and the user) continuous communication through different communication media. Besides the innumerable standardization activities, there is a great number of active research projects. On European level, the most important are the i2010 Intelligent Car Initiative, the eSafety Forum, and the COMeSafety, the CVIS, the SAFESPOT, the COOPERS and the SEVECOM project. The i2010 Intelligent Car Initiative is an European initiative with the goal to halve the number of traffic casualties by 2010. The eSafety Forum is an initiative of the European Commission, industry and other stakeholders and targets the acceleration of development and deployment of safety-related ITS systems. The COMeSafety project supports the eSafety Forum on the field of vehicle-to-vehicle and vehicle-to-infrastructure communication. In the CVIS project, attention is given to both technical and non-technical issues, with the main goal to develop the first free and open reference implementation of the CALM architecture. The SAFEST project investigates which data is important for safety applications, and with which algorithmsthis data can be extracted from vehicles and infrastructure. The COOPERS project mainly targets communication between vehicles and dedicated roadside infrastructure. Finally, the SEVECOM project researches security and privacy issues. Besides the European projects, research is also conducted in the United States of America (CICAS and VII projects) and in Japan (AHSRA, VICS, Smartway, internetITS). Besides standardization bodies and governmental organizations, also the industry has a considerable interest in ITS systems. In the scope of their ITS activities, a number of companies are united in national and international organizations. On an international level, the best known names are the Car 2 Car Communication Consortium, and Ertico. The C2C CC unites the large European car manufacturers, and focuses on the development of an open standard for vehicle-to-vehicle and vehicle-to-infrastructure communications based on the already well established IEEE 802.11 WLAN standard. Ertico is an European multi-sector, public/private partnership with the intended purpose of the development and introduction of ITS systems. On a national level, FlandersDrive and The Telematics Cluster / ITS Belgium are the best known organizations. Despite the worldwide activities regarding (cooperative) ITS systems, there still is no consensus about the wireless technology to be used in such systems. This can be put down to the fact that a large number of suitable technologies exist or are under development. Each technology has its specific advantages and disadvantages, but no single technology is the ideal solution for every ITS application. However, the different candidates can be classified in three distinct categories. The first group contains solutions for Dedicated Short Range Communication (DSRC), such as the WAVE technology. The second group is made up of several cellular communication networks providing coverage over wide areas. Examples are GPRS (data communication using the GSM network), UMTS (faster then GPRS), WiMAX (even faster then UMTS) and MBWA (similar to WiMAX). The third group consists of digital data broadcast technologies such as RDS (via the current FM radio transmissions, slow), DAB and DMB (via current digital radio transmissions, quicker) and DVB-H (via future digital television transmissions for mobiledevices, quickest). The previous makes it clear that ITS systems are a hot topic right now, and they receive a lot of attention from the academic world, the standardization bodies and the industry. Therefore, it seems like that it is just a matter of time before ITS systems will find their way into the daily live. Due to the large number of suitable technologies for the implementation of cooperative ITS systems, it is very hard to define which role the government has to play in these developments, and which are the next steps to take. These issues were addressed in reports produced by the i2010 Intelligent Car Initiative and the CVIS project. Their state of the art overview revealed that until now, no country has successfully deployed a fully operational ITS system yet. Seven EU countries are the furthest and are already in the deployment phase: Sweden, Germany, the Netherlands, the United Kingdom, Finland, Spain and France. These countries are trailed by eight countries which are in the promotion phase: Denmark, Greece, Italy, Austria, Belgium,Norway, the Czech Republic and Poland. Finally, the last ten countries find themselves in the start-up phase: Estonia, Lithuania, Latvia, Slovenia, Slovakia, Hungary, Portugal, Switzerland, Ireland and Luxembourg. These European reports produced by the i2010 Intelligent Car Initiative and the CVIS project have defined a few policy recommendations which are very relevant for the Belgian and Flemish government. The most important recommendations for the Flemish government are: • Support awareness: research revealed that civilians consider ITS applications useful, but they are not really willing to pay for this technology. Therefore, it is important to convince the general public of the usefulness and the importance of ITS systems. • Fill the gaps: Belgium is situated in the promotion phase. This means that it should focus at identifying the missing stakeholders, and coordinating national and regional ITS activities. Here it is important that the research activities are coordinated in a national and international context to allow transfer of knowledge from one study to the next, as well as the results to be comparable. • Develop a vision: in the scope of ITS systems policies have to be defined regarding a large number of issues. For instance there is the question if ITS users should be educated, meaning that the use of ITS systems should be the subject of the drivers license exam. How will the regulations be for the technical inspection of vehicles equipped with ITS technology? Will ITS systems be deployed on a voluntary base, or will they e.g. be obliged in every new car? Will the services be offered by private companies, by the public authorities, or by a combination of them? Which technology will be used to implement ITS systems? These are just a few of the many questions where the government will have to develop a point of view for. • Policy coordination: ITS systems are a policy subject on an international, national and regional level. It is very important that these policy organizations can collaborate in a coordinated manner. • Iterative approach to policy development: developing policies for this complex matter is not a simple task. This asks for an iterative approach, where policy decisions are continuously refined and adjusted

    Controlo de acesso ao meio em comunicações veiculares de tempo-real

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    Despite several preventive measures, the number of roadway accidents is still very high, being considered even a problem of public health by some entities. This thesis has as global purpose of contributing to the reduction of that number of accidents, and consequent fatalities, by using safety-related applications that use communication among vehicles. In particular, the primary goal is guaranteeing that communication between users in vehicular environments is done with appropriate time bounds to transfer safety-critical information. In detail, it is studied how to manage the scheduling of message’s transmissions (medium access control - MAC), in order to define precisely who will communicate and when is the appropriate instant. The preferable situation where a communication infrastructure is present with full coverage (RSUs) is also studied, from which medium access control is defined precisely, and vehicles (OBUs) become aware of medium utilization. Also, sporadic situations (e.g., absence of RSUs) are studied in which the communication network is “ad hoc” and solely formed by the current vehicles. It is used the recently WAVE / IEEE 802.11p standard, specific for vehicular communications, and it is proposed a TDMA based solution, with appropriate coordination between RSUs in order to effectively disseminate a critical safety event. It is taken into account two different ways of choosing the instant for the initial broadcast, and both cases are compared. In case there is no infrastructure available, methods are derived to minimize communication medium access collisions, and to maximize the available bandwidth. The results reflect the total end-to-end delay, and show that adequate times are attained, and meet with the requisites for the type of applications being considered. Also, enhancements are obtained when using the alternate choice for the initial broadcast instant.Apesar de diversas medidas preventivas, o número de acidentes rodoviários continua a ser muito elevado, sendo mesmo considerado uma questão de saúde pública por algumas entidades. Esta tese tem como objetivo geral contribuir para a redução desse número de acidentes, e consequentes fatalidades, através da utilização de aplicações de segurança que envolvem comunicação entre veículos. Em particular, o objetivo principal é garantir que a comunicação entre utentes, em ambientes veiculares, seja efetuada com limites temporais apropriados à transferência de informações críticas. De forma mais detalhada, é estudada a gestão do escalonamento das transmissões (controlo de acesso ao meio – MAC) que irá definir quem vai comunicar e quando o pode fazer. São estudadas situações (desejadas) onde há uma infra-estrutura de comunicações com cobertura integral (RSUs), a partir da qual se faz a coordenação do acesso ao meio pelos veículos (OBUs), e situações (esporádicas, por ausência de RSU) em que a rede de comunicação é “ad hoc” e apenas constituída pelos veículos presentes. Utiliza-se a recente norma WAVE / IEEE 802.11p, específica para comunicações veiculares, e propõe-se uma solução baseada em TDMA, com coordenação apropriada entre RSUs para disseminação efetiva de um evento crítico de segurança. A escolha do instante para o broadcast inicial do evento de segurança também é tida em conta, e são comparados dois casos distintos. No caso da ausência de infraestrutura, derivam-se métodos para minimizar colisões no acesso ao meio de comunicação, e maximizar a largura de banda disponível. Os resultados refletem o atraso total end-to-end, mostrando tempos apropriados para os requisitos das aplicações em causa, e evidenciando melhorias aquando da escolha alternativa para o instante do broadcast inicial.Programa Doutoral em Engenharia Eletrotécnic

    Virtual Reality Architecture Oriented Wireless Connection For Future Generation Virtual Reality Devices

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    In order to enhance the user experience of virtual reality (VR) devices, VR multi-user environments and wireless connections must support as the latest generation of VRdevices. Wireless network-based wireless communication devices (WLANs) are popular consumer devices with high throughput and low cost using incompatible bands. However, the use of WLANs can cause packet delivery delays, due to their distributed nature when accessing channels. In this paper, we carefully discuss wireless VR via WLAN, and we request an efficient wireless multiuser VR communication architecture, as well as providing communication for VR. Because the architecture proposed in this paper uses many WLAN standards, based on the characteristics of each VR traffic chain, it is agreed that it supports the efficient sending of massive uplink data generated by several VR devices, and provides adequate frame rates and video control frames. rate for high-quality VR services. We conduct evaluations that are supported to improve exceptional applications than are supporte

    Investigate the Development of a Wireless Flight Test System

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    This thesis describes the development and fight testing of a wireless flight test data acquisition system based on the IEEE 802.11 a/b/g protocols using low cost Commercial-Off-The-Shelf (COTS) equipment and software. The tested system consists of a video node, an Attitude Heading Reference System (AHRS), an Access Point and a User Interface Node. The video node consists of an IP Camera which was used to demonstrate the viability of including video recording as a service in an aircraft. The Attitude Heading Reference System was integrated with a GPS and a serial device server. The User Interface Node was installed with moving map software which receives the data from the AHRS and GPS to display flight information including topographic maps, attitude, heading, and velocity and roll/pitch/yaw rates. It was also used to record data from the video node. The Access Point was used to configure the network in the "Infrastructure mode". The system was also tested in the "Ad-Hoc mode" i.e., without an Access Point and suggestions for improving the performance of a system in the Ad-Hoc mode were made. The Infrastructure mode was flight tested in a Cessna 172. The data logged from the wireless AHRS during the flight test shows that it performed at its rated specification and that no data was lost due to disconnection in the wireless system. The post flight test data processing shows that the wireless system provided a secure, interference free connection with a throughput of 1.102 Mbps. By comparison, the popular ARINC 429 data bus supports a data rate of 100 Kbps. The developed system demonstrates the applicability of wireless networking using the IEEE 802.11 protocols for application in flight testing and based on this, future work like extending the system to include more number of clients is presented
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