Prakash Veeraraghavan

A novel image-based implicit password authentication system (IPAS) for mobile and non-mobile devices

Abstract Authentication is the first line of defense against compromising confidentiality and integrity. Though traditional login/password-based schemes are easy to implement, they have been subjected to several attacks. As an alternative, token and biometric-based authentication systems were introduced. However, they have not improved substantially to justify the investment. Thus, a variation to the login/password scheme, viz. graphical scheme was introduced. But it also suffered due to shoulder-surfing and screen-dump attacks. In this paper, we introduce a framework of our proposed (IPAS) Implicit Password Authentication System, which is immune to the common attacks suffered by other authentication schemes.

Routing mechanisms and cross-layer design for Vehicular Ad Hoc Networks: A survey

Vehicular Ad-Hoc Network (VANET) will pave the way to advance automotive safety and occupant convenience. The potential VANET applications present diverse requirements. VANET shows unique characteristics and presents a set of challenges. The proposed VANET applications demand reliable and proficient message dissemination techniques. Routing techniques proposed for Mobile Ad-Hoc Network (MANET) do not cater for the characteristics of VANET. The need for novel routing techniques, exclusively designed for VANET has been recognised. This paper analyses different routing techniques proposed specifically for VANET. Unique characteristics of VANET pose challenges to traditional layered architecture where different layers make independent decisions. Mobility, absence of global view of network, random changes in topology, poor link quality and varied channel conditions have encouraged the paradigm shift to cross-layer approach. In order to optimise the performance of VANET, architectures based on cross-layer approach have been proposed by the researchers. The paper also surveys such cross-layer paradigm based solutions for VANET and concludes with an analytical summary.

SmartVANET: The Case for a Cross-Layer Vehicular Network Architecture

Dedicated Short Range Communication (DSRC) based Vehicular Ad Hoc Network (VANET) provides an opportunity to enable communication-based cooperative safety systems in order to decrease road traumas and improve traffic efficiency. VANET also offers a wide range of commercial and infotainment applications. VANET exhibits unique characteristics that create new challenges. This paper discusses the DSRC technology and its shortcomings in order to achieve reliable content dissemination. To optimise the performance of the vehicular networks, a novel network architecture using the cross-layer paradigm is presented. The architecture is called Smart Vehicular Ad-hoc Network (SmartVANET) architecture. The proposed SmartVANET architecture can support safety, traffic management and commercial applications. The SmartVANET architecture complies with the DSRC channel plan. The architecture divides road into segments and assigns a service channel to each segment. The SmartVANET combines a segment based clustering technique with a hybrid Medium Access Control (MAC) mechanism (termed as the Smart MAC protocol). Using cross-layer integration, SmartVANET also provides a solution for broadcast storm problems and offers scalability. The paper presents the SmartVANET architecture and argues its advantages.

Fine-grained updates in database management systems for flash memory

The growing storage capacity of flash memory (up to 640GB) and the proliferation of small mobile devices such as PDAs and mobile phones makes it attractive to build database management systems (DBMSs) on top of flash memory. However, most existing DBMSs are designed to run on hard disk drives. The unique characteristics of flash memory make the direct application of these existing DBMSs to flash memory very energy inefficient and slow. The relatively few DBMSs that are designed for flash suffer from two major short-comings. First, they do not take full advantage of the fact that updates to tuples usually only involve a small percentage of the attributes. A tuple refers to a row of a table in a database. Second, they do not cater for the asymmetry of write versus read costs of flash memory when designing the buffer replacement algorithm. In this paper, we have developed algorithms that address both of these short-comings. We overcome the first short-coming by partitioning tables into columns and then group the columns based on which columns are read or updated together. To this end, we developed an algorithm that uses a cost-based approach, which produces optimal column groupings for a given workload. We also propose a heuristic solution to the partitioning problem. The second short-coming is overcome by the design of the buffer replacement algorithm that automatically determines which page to evict from buffer based on a cost model that minimizes the expected read and write energy usage. Experiments using the TPC-C benchmark S.T. Leutenegger, D. Dias, A modeling study of the TPC-C benchmark, in: Proceedings of ACM SIGMOD, 1993, pp. 22-31] show that our approach produces up to 40-fold in energy usage savings compared to the state-of-the-art in-page logging approach.

A survey of lower layer technologies for Vehicle-to-Vehicle communication

Vehicle-to-Vehicle (V2V) communication is an evolving research field that has potential to augment safety on our roads. Safety focused V2V communication also offers convenience and commercial applications in order to enhance driving comfort and pleasure. V2V communication demonstrates unique characteristics and consequently reliable network access has become crucial to exploit a wide spectrum of applications. Development of complex networking protocols, ingenious medium access control (MAC) techniques and robust communication technology are the main challenges to reliable and pragmatic V2V communication. This paper provides survey of lower layer technologies proposed for V2V communication and concludes with analytical summary drawn from the survey.

Trust in mobile Ad Hoc Networks

Securing a Wireless Ad Hoc Network is a major concern for researchers. Due to varied characteristics of Ad Hoc Networks, they are vulnerable to internal as well as external attacks. Many solutions have been proposed and currently being improved upon in this area. Most of these solutions involve encryption; secure routing, key management etc. Each of them is designed to operate in a particular situation, which may fail to work successfully in other scenarios. The present work in this paper offers an alternate to improve the trustworthiness of the neighbourhood and secure the routing procedure. It helps in computing the trust in neighbours and selecting the most secure route from the available ones for the data transfer. It also helps detecting the compromised node and virtually it removing from the network.

Energy efficient medium access control with single sleep schedule for wireless sensor networks

S-MAC is a robust medium access control protocol for wireless sensor networks which is designed to be energy efficient. S-MAC nodes reduce energy expenditure by periodically turning off their receivers (sleeping) in a coordinated manner. Nodes form virtual clusters based on common sleep schedules. However, some nodes in S-MAC may have to wake up more often than the other nodes. This paper demonstrates in some wireless sensor networks using S-MAC, a significant proportion of the nodes may have to stay awake much longer than envisaged. The paper then proposes a modification of the protocol to eliminate the need for some nodes to stay awake longer than the other nodes. The modified version improves the energy efficiency and increases the life span of a wireless sensor network.

QoS multicast routing using Explore Best Path

One of the most active research areas in networking is quality of service (QoS). The most fundamental requirement for QoS is the ability to find a path that can provide the required network resources between two nodes. These nodes will use QoS routing to find a feasible QoS path between both of them. In this paper, we present a distributed multicast QoS routing architecture that uses probes to find a quick and scalable QoS path between a joining router and the multicast tree. Any router that receives this probe will only know its neighbours and it will create a link to the previous router from where the probe comes from. The joining router will join the multicast tree by following these links on each router until it reaches the tree. Analysis of this method shows that the convergence rate and message overhead is lower than other similar schemes.

An Energy Efficient Wireless Sensor MAC Protocol with Global Sleeping Schedule

Wireless sensor networks (WSNs) aim to fulfill the need for reliable and fault-tolerant sensing services. This has made wireless sensor networks a very active research area. SMAC is an energy efficient sensor MAC protocol. An S-MAC problem is that border nodes have to adopt multiple sleeping schedules, which speed up the energy depletion of border nodes. In this paper, S-MACL is proposed to overcome this problem. In S-MACL, a global sleeping schedule is used. The simulations result shows that S-MACL achieves a greater level of energy efficiency than S-MAC.

Implementing label filters on a shared tree mobile multicast architecture

This paper describes an architecture that filters packets within a subset of nodes on an existing shared multicast tree. The path connecting the group of nodes that want to communicate privately on the existing tree was given a label. These labels are used to route one-to-one and group communication traffic for selected nodes on a multicast tree. Nodes connected to the tree but are not on this label path do not receive any filtered packets. This filter architecture reduces network resource waste by utilising the existing network resources on the multicast tree like quality of service (QoS). In this paper, we also describe how this architecture can be used for mobile communication when implemented in a shared tree mobile multicast architecture.