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Zheng B.,University of California at Riverside | Liang H.,University of California at Riverside | Zhu Q.,University of California at Riverside | Yu H.,InfoTechnology Center | Lin C.-W.,InfoTechnology Center
Proceedings of IEEE Computer Society Annual Symposium on VLSI, ISVLSI | Year: 2016

To support emerging applications in autonomous and semi-autonomous driving, next-generation automotive systems will be equipped with an increasing number of heterogeneous components (sensors, actuators and computation units connected through various buses), and have to process a high volume of data to percept the environment accurately and efficiently. Challenges for such systems include system integration, prediction, verification and validation. In this work, we propose an architecture modeling and exploration framework for evaluating various software and hardware architecture options. The framework will facilitate system integration and optimization, and enable validation of various design metrics such as timing, reliability, security and performance. © 2016 IEEE.


Bansal G.,InfoTechnology Center | Lu H.,University of Notre Dame | Kenney J.B.,InfoTechnology Center | Poellabauer C.,University of Notre Dame
20th ITS World Congress Tokyo 2013 | Year: 2013

V2V Safety Communications in the US and Europe will utilize the IEEE 802.11p MAC protocol, which provides a frame prioritization mechanism known as Enhanced Distributed Channel Access (EDCA). Safety messages can often be classified by the sender as "routine" or "critical," and placed in different Access Categories (ACs) to give the critical messages priority channel access. In this paper we address the problem of how to further classify otherwise "routine" safety messages into priority classes. In particular, we describe an algorithm that computes a metric called Suspected Tracking Error (STE) and assigns the priority class of a message based on the current value of STE. Packets with the largest STE are assigned to the highest priority class, along with those classified as "critical" according to other criteria. Packets with moderate STE are assigned to the lower priority class. While other approaches using STE have emphasized giving more transmission opportunities to vehicles experiencing high dynamics, this approach instead provides the advantage of higher probability of successful delivery. Simulation results demonstrating the benefit of the proposed algorithm are provided.


Sepulcre M.,InfoTechnology Center | Sepulcre M.,University Miguel Hernández | Gozalvez J.,University Miguel Hernández | Altintas O.,InfoTechnology Center | Kremo H.,InfoTechnology Center
Ad Hoc Networks | Year: 2016

Cooperative vehicular networks require the exchange of positioning and basic status information between neighboring nodes to support vehicular applications. The exchange of information is based on the periodic transmission/reception of 1-hop broadcast messages on the so called control channel. The dynamic adaptation of the transmission parameters when broadcasting such messages will be key for the reliable and efficient operation of vehicular networks. To this aim, vehicular networks utilize congestion control protocols to control the channel load, typically through the adaptation of the transmission parameters based on certain channel load metrics. Awareness control protocols are also required to adequately support cooperative vehicular applications. These protocols typically adapt the transmission parameters of periodic broadcast messages to ensure each vehicle's capacity to detect, and possibly communicate, with the relevant vehicles and infrastructure nodes present in its local neighborhood. To date, congestion and awareness control protocols have been normally designed and evaluated separately, although both will be required for the reliable and efficient operation of vehicular networks. In this context, this paper proposes and evaluates INTERN, a new control protocol that integrates two congestion and awareness control processes. The simulation results obtained for three different scenarios demonstrate that INTERN is able to satisfy the applications' requirements of all vehicles, while effectively controlling the channel load. The results obtained highlight the challenges ahead with emerging automated vehicles. © 2015 Elsevier B.V.


Kaul S.,Rutgers University | Gruteser M.,Rutgers University | Rai V.,InfoTechnology Center | Kenney J.,InfoTechnology Center
2011 8th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks, SECON 2011 | Year: 2011

Emerging applications rely on wireless broadcast to disseminate time-critical information. For example, vehicular networks may exchange vehicle position and velocity information to enable safety applications. The number of nodes in one-hop communication range in such networks can be very large, leading to congestion and undesirable levels of packet collisions. Earlier work has examined such broadcasting protocols primarily from a MAC perspective and focused on selective aspects such as packet error rate. In this work, we propose a more comprehensive metric, the average system information age, which captures the requirement of such applications to maintain current state information from all other nearby nodes. We show that information age is minimized at an optimal operating point that lies between the extremes of maximum throughput and minimum delay. Further, while age can be minimized by saturating the MAC and setting the CW size to its throughput-optimal value, the same cannot be achieved without changes in existing hardware. Also, via simulations we show that simple contention window size adaptations like increasing or decreasing the window size are unsuitable for reducing age. This motivates our design of an application-layer broadcast rate adaptation algorithm. It uses local decisions at nodes in the network to adapt their messaging rate to keep the system age to a minimum. Our simulations and experiments with 300 ORBIT nodes show that the algorithm effectively adapts the messaging rates and minimizes the system age. © 2011 IEEE.


Yu H.,InfoTechnology Center | Talpin J.-P.,French Institute for Research in Computer Science and Automation | Shukla S.,Virginia Polytechnic Institute and State University | Joshi P.,Virginia Polytechnic Institute and State University | Shiraishi S.,InfoTechnology Center
CEUR Workshop Proceedings | Year: 2014

Current embedded systems are increasingly more complex and heterogeneous, but they are expected to be more safe, reliable and adaptive. In consideration of all these aspects, their design is always a great challenge. Developing these systems with conventional design approaches and programming methods turns out to be difficult. In this paper, we mainly present the informative background and the general idea of an ongoing yet young research project, including the model-based design and an architecture-centric approach, to address previous challenges. Our idea adopts a formal-methods-based model integration approach, dedicated to architecture-centric virtual integration for embedded software systems, in an early design phase. We thus expect to improve and enhance Correct By Construction in the design. The considered formal methods consist of timing specification, design by contracts, and semantics interoperability for models to be integrated in the system. The application domains of our approach include automotive and avionic systems.


Ozbilgin G.,Ohio State University | Ozguner U.,Ohio State University | Altintas O.,InfoTechnology Center | Kremo H.,InfoTechnology Center | Maroli J.,Ohio State University
IEEE Intelligent Vehicles Symposium, Proceedings | Year: 2016

In this paper, we analyze mixed traffic environments consisting of fully autonomous vehicles, vehicles capable of communication only, and manually driven vehicles to determine what self-generated content should be shared among peer vehicles for increased traffic intelligence. For this purpose, we present information sharing utility-cost tables for a variety of communication strategies. These tables are used to determine communication requirements in terms of bandwidth, distance, packet delay and loss rate tolerance. We specifically evaluate vehicle lane change events due to their role as foundational building blocks in most other traffic scenarios. The presented work demonstrates requirements for the communication systems in mixed-traffic environments based on sharing and fusing necessary sensor information using occupancy grid mapping. © 2016 IEEE.


Borota D.,Rutgers University | Ivkovic G.,Rutgers University | Vuyyuru R.,InfoTechnology Center | Altintas O.,InfoTechnology Center Co. | And 2 more authors.
IEEE Vehicular Technology Conference | Year: 2011

Vehicular networking has significant potential to enable diverse range of applications, including safety and convenience. As the number of vehicles and applications using wireless spectrum grow, one can expect to see a shortage of either spatially or temporally available spectrum. In this paper, we advocate that dynamic spectrum access for vehicles be the first step towards solving the spectrum shortage. For this, vehicles must be able to sense the availability of spectrum before attempting to transmit. The existence of other transmitters should be detected in order not to cause or experience interference. However, spectrum sensing in vehicular environments is a challenging task due to mobility, shadowing and other factors that govern vehicular environments. Therefore, spectrum sensing by a single vehicle may not be able to provide accurate information about the spectrum vacancies. Cooperative spectrum sensing, on the other hand, uses spatial diversity and can be employed to overcome the limitations associated with a single sensor/vehicle. In this paper, we investigate cooperative spectrum sensing performance in a vehicular environment for sensing signals transmitted from i) a roadside infrastructure and ii) radios located on other vehicles, by using energy-based detection of a transmitted pilot tone as an example. Our goal is to characterize the limits on detection speed and reliability of simple hard and soft cooperative energy-based schemes for this environment. We show how cooperation reduces sensing time by a factor of five in an AWGN channel. The cooperative sensing time reduction is far more significant in a vehicular environment with fading and shadowing. Finally, we illustrate how infrastructure-to-vehicle scenario favors soft equal gain combining while vehicle-to-vehicle scenario favors hard fusion OR rule. © 2011 IEEE.


Karagiannis G.,University of Twente | Altintas O.,InfoTechnology Center | Ekici E.,Ohio State University | Heijenk G.,University of Twente | And 3 more authors.
IEEE Communications Surveys and Tutorials | Year: 2011

Vehicular networking has significant potential to enable diverse applications associated with traffic safety, traffic efficiency and infotainment. In this survey and tutorial paper we introduce the basic characteristics of vehicular networks, provide an overview of applications and associated requirements, along with challenges and their proposed solutions. In addition, we provide an overview of the current and past major ITS programs and projects in the USA, Japan and Europe. Moreover, vehicular networking architectures and protocol suites employed in such programs and projects in USA, Japan and Europe are discussed. © 2011 IEEE.


Gorcitz R.A.,University Pierre and Marie Curie | Spathis P.,University Pierre and Marie Curie | Dias De Amorim M.,University Pierre and Marie Curie | Wakikawa R.,InfoTechnology Center | Fdida S.,University Pierre and Marie Curie
IWCMC 2011 - 7th International Wireless Communications and Mobile Computing Conference | Year: 2011

The future of Vehicular Ad-Hoc Networks (VANET) will rely mainly on the support of efficient information dissemination protocols, whether we talk about safety applications that warn the driver of an imminent collision, a simple update on traffic conditions, or road-side advertisements. One of the greatest challenges when designing such protocols is how to deliver packets efficiently in a highly mobile environments under intermittent connectivity. Surprisingly, this problem has been under-investigated in the literature. In this paper, we propose, design, and evaluate SERVUS1, a robust dissemination protocol that guarantees packet propagation with high delivery ratio and low overhead. SERVUS includes a new broadcast management mechanism that takes advantage of the inherent behavioral properties of the VANET environment. In particular, the proposed protocol can update isolated nodes (or clusters) with missing information while ensuring homogeneous information dispersal at low overhead. Through a number of analyses, we show that SERVUS is highly efficient with regard to the tradeoff between reliability and cost, and overcomes important issues like the broadcast storm problem and the topological temporal fragility. © 2011 IEEE.


Yu H.,InfoTechnology Center | Joshi P.,Virginia Polytechnic Institute and State University | Talpin J.-P.,French Institute for Research in Computer Science and Automation | Shukla S.,Virginia Polytechnic Institute and State University | Shiraishi S.,InfoTechnology Center
Proceedings - Design Automation Conference | Year: 2015

Model-Based Engineering (MBE) is a promising approach to cope with the challenges of designing the next-generation automotive systems. The increasing complexity of automotive electronics, the platform, distributed real-time embedded software, and the need for continuous evolution from one generation to the next has necessitated highly productive design approaches. However, heterogeneity, interoperability, and the lack of formal semantic underpinning in modeling, integration, validation and optimization make design automation a big challenge, which becomes a hindrance to the wider application of MBE in the industry. This paper briefly presents the interoperability challenges in the context of MBE and summarizes our current contribution to address these challenges with regard to automotive control software systems. A novel model-based formal integration framework is being developed to enable architecture modeling, timing specification, formal semantics, design by contract and optimization in the system-level design. The main advantages of the proposed approach include its pervasive use of formal methods, architecture analysis and design language (AADL) and associated tools, a novel timing annex for AADL with an expressive timing relationshIP language, a formal contract language to express component-level requirements and validation of component integration, and the resulting high assurance system delivery. © 2015 ACM.

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