Cooperative Vehicle Safety System for VANETs

Cooperative Vehicle Safety System for VANETs COOPERATIVE VEHICLE SAFETY SYSTEM FOR VEHICULAR AD-HOC NETWORKS T. Sujitha, Final year M.E(CSE), ABSTRACT Vehicular ad hoc networks (VANETs) are a one form of wireless networks used for vehicles communication among themselves on roads. The conventional routing protocols are suitable for mobile ad hoc networks (MANETs). But it’s poorly in VANETs. As communication links break often happen in VANETs compare than in MANETs, the reliable routing is more difficult in the VANET. Research work has been done to the routing reliability of VANETs on highways. In this paper, we use the cooperative vehicle safety system for VANETs. The cooperative vehicle safety system helps to capture the future positions of the vehicles and determines the reliable routes preemptively. This paper is the first to propose a cooperative vehicle safety system for VANETs gives quality-of-service (QoS) support in the routing process. A new mechanism is developed to find the most reliable route in the VANET from the source vehicle to the destination vehicle. Through the simulation results, that the proposed scheme s ignificantly give good result compare than other literature survey. Keywords- vehicular ad hoc network (VANET),DSRC, IEEE 802.11,sensor,OBU,RSU. 1.INTRODUCTION Every day, a most of people die, and many people are injured in traffic accidents around the world. The desire to improve road safety information among vehicles to prevent accidents and improve road safety was the main motivation behind the development of vehicular ad hoc networks (VANETs). VANETs are a promising technology to enable communications among vehicles on roads. They are a special form of mobile ad hoc networks (MANETs) that provide vehicle-to-vehicle communications. It is assumed that each vehicle is equipped with a wireless communication facility to provide ad hoc network connectivity. VANETs tend to operate without an infrastructure, each vehicle in the network can send, receive, and relay messages to other vehicles in the network. Figure 1.1 Structure of Vanet Ad-hoc Networks This way, vehicles can exchange real-time information, and drivers can be informed about road traffic conditions and other travel-related information. The most challenging issue is potentially the high mobility and the frequent changes of the network topology. In VANETs, the network topology could vary when the vehicles change their velocities and/or lanes. These changes depend on the drivers and road situations and are normally not scheduled in advance. Embedded wireless devices are the main components of evolving cooperative active safety systems for vehicles. These systems, which rely on communication between vehicles, deliver warning messages to drivers and may even directly take control of the vehicle to perform evasive maneuvers. The cyber aspects of such applications, including communication and detection of vehicle information are tightly coupled with physical dynamics of vehicles and drivers behavior. Recent research on such cooperative vehicle safety (CVSS) systems has shown that significant performance improvement is possible by coupling the design of the components of the systems that are related to vehicle dynamics with the cyber components that are responsible for tracking other cars and detecting threats. The types of possible actions and warnings in vehicle safety systems range from low-latency collision avoidance or warning systems to moderate-latency system that provide heads up information about possible dangers in the non immediate path of the vehicle. The main differences of these systems are the sources and means of information dissemination and acquisition. In active safety systems, vehicles are required to be continuously aware of their neighborhood of few hundred meters and monitor possible emergency information. This task can be achieved by frequent real time communication between vehicles over dedicated short range communication (DSRC) channel. In addition to inter-vehicle communication; roadside devices may also assist vehicles in learning about their environment by delivering traffic signal or pedestrian related information at intersections. The main requirement of these active safety systems is the possibility of delivering real-time acquired information to and between vehicles at latencies of lower than few hundred milliseconds. Prototypes of such systems are being developed by many automotive manufacturers. 2. EXISTING SYSTEM In DSRC based safety systems, the cyber components are selected so that they meet the requirements of active safety. Nevertheless, the existing designs fall short of supporting a full-fledged CVSS in which a large number of vehicles communicate and cooperate with each other. The main reason behind the issues with the current designs is the level of separation in the design of different components. Later in this paper we describe methods to achieve better performance by further cooperation of the physical and cyber sub-components. In the next subsection we describe existing active safety CVSS systems and their designs. Figure 1.2 Communication in VANET systems. The traditional design of the CVS system, based on the structure depicted, is a straightforward design following the recommendations of an early report by vehicle safety communication consortium (VSCC). According to this report, it is suggested that vehicles should transmit tracking messages every 100ms, to a distance of at least 150m (avg. 250m). Therefore, the message generation module in becomes a periodic process that outputs a sample of the current state of the vehicle in a message every 100msec. The DSRC radio power is set to reach the suggested distance. Given the issues of the above design in crowded networks, several enhancements have recently been proposed to improve the performance of CVS systems beyond the early solutions set forth by VSCC. One such method is the work in [22] that proposes to fairly allocate transmission power across all cars in a max-min fashion; this method helps reduce the load at every point of a formulated 1-D highway and thus reserves bandwidth for emergency messages with higher priorities. This method assumes a predefined maximum load as the target. In another work, a message dispatcher is proposed to reduce required data rate by removing duplicate elements, here, the idea is that many applications require the same data elements from other vehicles. The message dispatcher at the sender side will group data elements from application layer (i.e., the source) and decides how frequently each data element should be broadcast. The above methods focus on the computing module, as defined in this section, and try to improve its performance through observing the behavior of the application, or by incorporating limited physical process information in the design of the computing module. While the above improvements do enhance the performance of CVS systems, these designs do not consider the mutual effects of computation, communication and physical processes on each other. In this, try to identify such mutual effects and propose a design that uses the knowledge of the tight coupling of cyber and physical processes to the benefit of a CVSS system. DESTINATION SEQUENCED DISTANCE VECTOR (DSDV) DSDV is a proactive protocol that maintains route to all the destinations before requirement of the route. Each node maintains a routing table which contains next hop, cost metric towards each destination and a sequence number that is created by the destination itself. This table is exchanged by each node to update route information. A node transmits routing table periodically or when significant new information is available about some route. Whenever a node wants to send packet, it uses the routing table stored locally. For each destination, a node knows which of its neighbor leads to the shortest path to the destination. DSDV is an efficient protocol for route discovery. Whenever a route to a new destination is required, it already exists at the source. Hence, latency for route discovery is very low. DSDV also guarantees loop-free paths. 3. PROPOSED SYSTEM Cooperative message authentication protocol, which augments the basic short group signature protocol by mitigating the computation overhead in the regular broadcast phase. According to, the verification time for short group signature is 11ms with a 3 GHz Pentium IV system. In a typical public safety application, each vehicle broadcasts safety messages every 300 ms, which implies that each vehicle can at most process messages from other vehicles in a stable system. However, according to the measurement, there may exist as many as 87 vehicles broadcasting messages within the 300m communication range of a receiving vehicle, far exceeding its processing capability. Therefore, we propose a cooperative message authentication protocol to fill the gap between the workload and the processing capability. 3.1 PROTOCOL IMPLEMENTATION RSUs broadcast I-public keys, G-public keys of themselves and their neighbor RSUs with certificates and identities of revoked RSUs in their neighborhoods regularly. Authorities employ benign RSUs around compromised RSUs to implement revocation by regular broadcasting those compromised RSUs’ identities. When a vehicle detects the hello message, it starts registration by sending its I-public key and the certificate to the RSU if the RSU is not revoked. Normally, a public key should not be encrypted. However, in our system model, each vehicle’s I-public key is unique, so it is also an identifier of the vehicle. We encrypt it to protect vehicle’s privacy. The RSU sends the hash value of the G-private key which plans to be assigned to the vehicle and the signature of the hash value, vehicle’s I-public key and RSU’s I-public key to the vehicle. RSU’s I-public key is also unique. The vehicle can identify the RSU’s legitimacy after it verifies this message because the RSU uses its I-private key in the message. The vehicle encrypts its Npri and the timestamp by using authorities’ public key. Then, it sends the encryption data with the timestamp and the signature of corresponding information, message 4, to the RSU. The encryption of its Npri and the timestamp is a commitment. It can be useed to detect illegitimate users later. Meanwhile, the signature signed by the vehicle binds vehicle’s information and the assigned G-private key. Then, the RSU cannot re-map them because the RSU does not have vehicle’s I-private key. The RSU sends the G-private key to the vehicle. The vehicle finishes registration procedure after it gets a valid G-private key. Then, the RSU stores the information, as in the local database. The signature in the fifth item is the signature that the RSU receives in message. If authorities need the information of a vehicle when there is a dispute, the RSU has to send the vehicle’s corresponding information to authorities. 3.2 PERFORMANCE EVALUATION The performance of the proposed algorithm is evaluated through network simulator version 2. A cooperative message authentication protocol(CMAP) is presented to alleviate vehicles computation burden. In the protocol, because vehicles share their verification results with each other in a cooperative way, the number of safety messages that each vehicle needs to verify will be reduced greatly. A new research issue of the protocol is how to select verifiers in the city road scenario. Thus, we propose three verifiers selection algorithms, n-nearest method, most-even distributed method and the compound method for the CMAP. Performance metrics are utilized in the simulations for performance comparison. Packet arrival rate The ratio of the number of received data packets to the number of total data packets sent by the source. Energy consumption The energy consumption for the entire network includes transmission energy consumption for both the data and control packets. Average end-to-end delay The average time elapsed for delivering a data packet within a successful transmission. Control overhead The average number of transmitted control bytes per second, including both the data packet header and the control packets. Collision rate The average Collision rate for the entire data transmission from source to destination is much controlled and reduced when compared to the existing protocol. 4. ELLIPTIC CURVE DIGITAL SIGNATURE ALGORITHM ECDSA is Elliptic Curve Cryptosystem (ECC)-based implementation of the commonly used digital signature algorithm. ECC provides the same security level as the other discrete logarithm approaches, while the size of the required ECC credentials is much smaller than that of the discrete logarithm systems. The WAVE security service adopt ECDSA-based message authentication for vehicular communications. Two standard elliptic curves namely P-224 and P-256 have been suggested for general purpose message authentications, and certificate authentications in VANETs. A VANET entity is required to transmit periodic safety messages containing its current coordinates, speed, acceleration etc. to the neighboring devices. The typical interval for safety message broadcasts ranges from 100 ms to 300 ms. An authentication scheme has to be incorporated in order to provide reliability and trust for the delivered safety information. Received messages are verified by the receiving entity to ensure the message integrity, and authenticity of sender’s identity. Unfortunately signature verification incurs a cryptographic processing delay at the verifier’s end. Although the verification delay for ECDSA is in the order of milliseconds, with hundreds of vehicles in a dense traffic scenario, an OBU would receive an enormous amount of periodic messages per unit time causing a bottleneck to the authentication process at the receiver end. If OBUs are configured to broadcast their periodic messages every 100 ms, under a heavy traffic scenario, many of the safety messages would either be discarded due to the constrained buffer size of the verification process, or accepted without any verification. Therefore in busy traffic hours, a receiver of vehicular messages would either risk a fatal road-traffic consequence, or it would reject a significant portion of received messages without authenticating when its maximum verification capacity is reached. The current WAVE standards do not include an efficient anonymous authentication scheme for vehicular messages, or even an intelligent authentication strategy which can efficiently verify from a massive number of vehicular safety/application messages. 5. CONCLUSION The proposed protocol designed an identity-based anonymous user-authentication scheme and a cross-layer verification approach for WAVE-enabled VANET’s safety messages. A variation of the conventional ECDSA approach is used with the identity-based signature approach where the common geographical area information of signing vehicles is taken as the signer’s identity. This exempts a vehicle from the mandatory inclusion of a trusted third-party certificate with each broadcast message in a VANET while a user is still identifiable by the trusted third-party up on a dispute. A cross-layer message verification scheme verifies the received messages based on their MAC traffic class and traffic intensity. This ensures that under the rush hour congestion or traffic accident most important messages will not be missed by the verifier. Security analysis and performance evaluation justify our authentication and verification approach for WAVE-enabled vehicular communications. REFERENCES [1] C. E. Perkins and E. M. Royer, â€Å"Ad-hoc on-demand distance vector routing,†in Proc.2nd IEEE WMCSA 1999. [2] V. A. Davis, â€Å"Evaluating mobility models within an ad hoc network,† M.S. thesis, Colorado Sch. Mines Golden, CO, USA, 2000. [3] A. Ferreira, â€Å"On models and algorithms for dynamic communication networks: The case for evolving graphs,† presented at the 4e rencontres francophones sur les ALGOTEL, Meze, France, 2002. [4] M. Rudack, M. Meincke, K. Jobmann, and M. Lott, â€Å"On traffic dynamical aspects of inter vehicle communications (IVC),† in Proc. IEEE Veh.Technol. Conf., 2003. [5] H. Menouar, M. Lenardi, and F. Filali, â€Å"A movement prediction-base drouting protocol for vehicle-to-vehicle communications,† in Proc. 1st Int.V2V Communication Workshop, San Diego, CA, USA, 2005. [6] T. Taleb, M. Ochi, A. Jamalipour, N. Kato, and Nemoto â€Å"An efficient vehicle-heading based routing protocol for VANET networks,†in Proc.IEEE Wireless Communication ,2006. [7] G. M. T. Abdalla, M. A. Abu-Rgheff, and S. M. Senouci, â€Å"Current trends in vehicular ad hoc networks,† in Proc IEEE Global Inf. Infrastruct.Symp., Marrakech Morocco, 2007. [8] V. Namboodiri and L. Gao, â€Å"Prediction-based routing for vehicular adhoc networks,† IEEE Trans.Veh Technol, 2007. [9] K. T. Feng, C. H. Hsu, and T. E. Lu, â€Å"Velocity-assisted predictive mobility and location-aware routing protocols for mobile ad hoc networks,† IEEE Trans Technol, 2008. [10] J. Monteiro, â€Å"The use of evolving graph combinatorial model in routing protocols for dynamic networks,† in Proc. XV Concurso Latinoamericanode Tesis de Maestrà ¬a, 2008. [11] G. Pallis, D. Katsaros, M. D. Dikaiakos, oulloudes and L. Tassiulas,â€Å"On the structure and evolution of vehicular networks,† in Proc. IEEE/ACM Meeting Symp. MASCOTS, 2009. [12] S. C. Ng, W. Zhang, Y. Zhang, Y. Yang, and G. Mao, â€Å"Analysis of access and connectivity probabilities in vehicular relay networks,† IEEE. Areas Communication, 2011.

Bursitis :: essays research papers fc

Bursitis Does it hurt to move your arm? Is it tender and radiating pain to your neck and finger tips? Do you have a fever? If you answered yes to two or more of these questions then you may have typical joint injury called bursitis. Bursitis is an inflammation of the bursa that is easily prevented, detected and treated. Bursitis is a common condition that can cause much pain and swelling around an affected bursa. A bursa is a sac between body tissues that move against each other. They are filled with a lubricating liquid to minimize the fiction between the tissues. The bursa are found mostly in joints between skin and bone or bone and tendons. When you irritate these lubricating sacs, the bursae fill with fluid and become irritated and inflamed. This inflammation causes severe pain with movement of the joint, often limiting the movement of the affected area. Bursitis commonly strikes in the shoulders, elbows, knees, pelvis, hips or Achilles tendons. Bursitis can affect nearly anyone for any number of reasons. It affects mainly adults both male and female. The individuals most at risk are people who engage in excessive and improper stretching and people who are involved heavily in athletic training. Bursitis can be caused by many things. For one, it can be caused by injury or overuse of a joint. Strenuous unfamiliar exercise also can cause Bursitis. Plus, such diseases as gout, arthritis, and chronic infection of a joint can be likely causes. But frequently the cause of Bursitis can not be determined. The only ways to prevent getting it are to wear protective gear when exorcising, practice appropriate warm ups and cool downs during exercise and to maintain a high fitness level. Bursitis is an easily treatable disease. If you suspect that you have bursitis, you will probably seek the advice of a doctor. Most likely the doctor will look at your medical history and take some x-rays. If you are diagnosed with bursitis the doctor may prescribe some non-steroidal anti-inflammatory drugs and/or pain relievers and may make some cortisone injections into the bursa to relieve inflammation. Once at home you are expected rest the affected area as much as possible and to apply RICE ( rest, ice, compression and elevation of the inflamed joint). Also to prevent the joint from freezing you should begin moving and exercising the affected area as soon as possible. Most likely the problem will subside in 7 to

I am analyzing a transcript of Jamie’s Dream School Series1 and will be identifying and evaluating language features used Essay

I am analyzing a transcript of Jamie’s Dream School Series1 and will be identifying and evaluating language features used Starkey is a teacher and is in a position of authority and has a preconceived notion his students are not serious as such, sees the need to drive home a few key facts which includes the reason for their being in school. He does this by laying emphasis on repetitive pronouns e.g. ‘you’, ‘you’ve’ as he draws into the conversation. Connor interrupts and thus overlaps Starkey by saying â€Å"yeah right’ in response to Starkey’s comment on some animals being faster. Starkey finds this rude and considering his position of authority and preconceived notion of the students not being particularly bright, he responds in an equally insultive manner stating Connor was fat and couldn’t really move. At the point, the conversation changes from formal to informal and he uses ‘you’re† This sparks overlapping laughter and noise from the rest of the class. Connor takes it personal and uses colloquial/slang language ‘yeah’ and ‘man’ in his response and further insults Starkey who uses courtesy items in response â€Å"Yes // now// right in an attempt to change the conversation from informal back to formal and overlaps and repeats by stuttering nervously ‘this is, this is, this is† and â€Å"persona, persona† Connor maintains an informal note as evidenced in his use of contractions and informal words e.g. â€Å"shit†, I’ll†, â€Å"mate†, and â€Å"don’t†. and use of a false start â€Å"don’t start, alright don’t start at all† because he’s clearly upset. Starkey then remarks ‘problem there are wi wi with Jamie’s food they’ll be, lots of dieting opportunities now’. It seems Starkey repeats words when upset. Again here, he’s used â€Å"wi wi† and a contraction – â€Å"they’ll† indicates an informal tone. The conversation is still informal because Connor uses ’you’re† IT’S, and addresses Starkey as ’mate’ AND A HEDGE â€Å"d’ya† . He also sarcastic by using polite words â€Å"May I ask’ and immediately follows it by asking if Starkey has always been 4 feet tall. Starkey maintains a sarcastic note by replying ‘from the age of thirteen. This transcript started off on a formal note but turned out to be mainly informal. Connor’s final response :Okay† brings the conversation back to a forma note

Alphadon - Facts and Figures

Name: Alphadon (Greek for first tooth); pronounced AL-fah-don Habitat: Woodlands of North America Historical Period: Late Cretaceous (70 million years ago) Size and Weight: About one foot long and 12 ounces Diet: Insects, fruit and small animals Distinguishing Characteristics: Long, prehensile tail; long hind legs About Alphadon As is the case with many of the early mammals of the Mesozoic Era, Alphadon is known primarily by its teeth, which peg it as one of the earliest marsupials (the non-placental mammals represented today by Australian kangaroos and koala bears). Appearance-wise, Alphadon probably resembled a small opossum, and despite its tiny size (only about three-quarters of a pound soaking wet) it was still one of the largest mammals of late Cretaceous North America. Befitting its small stature, paleontologists believe that Alphadon spent most of its time high up in trees, well out of the way of the stomping tyrannosaurs and titanosaurs of its ecosystem. At this point, you may be wondering how a prehistoric marsupial ended up in North America, of all places. Well, the fact is that even   modern marsupials arent restricted to Australia; opossums, to which Alphadon was related, are indigenous to both North and South America, although they had to reinvade the north about three million years ago, when the Central American Isthmus rose up and connected the two continents. (During the Cenozoic Era, after the demise of the dinosaurs, huge marsupials were thick on the ground in South America; before their extinction, a few stragglers managed to find their way via Antarctica to Australia, the only place today where you can find plus-sized pouched mammals.)