There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

A survey on vehicular cloud computing

https://www.eecs.ucf.edu/~turgut/Research/Publications/Download/Boukerche-2011-ComputerNetworks.pdf

Survey Paper: Routing protocols in ad hoc networks: A survey

As wireless sensor networks continue to grow, so does the need for effective security mechanisms. Because sensor networks may interact with sensitive data and/or operate in hostile unattended environments, it is imperative that these security concerns be addressed from the beginning of the system design. However, due to inherent resource and computing constraints, security in sensor networks poses different challenges than traditional network/computer security. There is currently enormous research potential in the field of wireless sensor network security. Thus, familiarity with the current research in this field will benefit researchers greatly. With this in mind, we survey the major topics in wireless sensor network security, and present the obstacles and the requirements in the sensor security, classify many of the current attacks, and finally list their corresponding defensive measures.

Wireless Sensor Network Security: A Survey

Networks-on-chip (NoCs) represent a promising solution to complex on-chip communication problems. The NoC communication architectures considered so far are based on either completely regular or fully customized topologies. In this paper, we present a methodology to automatically synthesize an architecture which is neither regular nor fully customized. Instead, the communication architecture we propose is a superposition of a few long-range links and a standard mesh network. The few application-specific long-range links we insert significantly increase the critical traffic workload at which the network transitions from a free to a congested state. This way, we can exploit the benefits offered by both complete regularity and partial topology customization. Indeed, our experimental results demonstrate a significant reduction in the average packet latency and a major improvement in the achievable network through with minimal impact on network topology

"It's a small world after all": NoC performance optimization via long-range link insertion

A number of measurement studies have convincingly demonstrated that network traffic can exhibit a noticeable self-similar nature, which has a considerable impact on queuing performance. However, many routing protocols developed for MANETs over the past few years have been primarily designed and analyzed under the assumptions of either CBR or Poisson traffic models, which are inherently unable to capture traffic self-similarity. It is crucial to re-examine the performance properties of MANETs in the context of more realistic traffic models before practical implementation show their potential performance limitations. In an effort towards this end, this paper evaluates the performance of three well-known and widely investigated MANET routing protocols, notably DSR, AODV and OLSR, in the presence of the bursty self-similar traffic. Different performance aspects are investigated including, delivery ratio, routing overhead, throughput and end-to-end delay. Our simulation results indicate that DSR routing protocol performs well with bursty traffic models compared to AODV and OLSR in terms of delivery ratio, throughput and end-to-end delay. On the other hand, OLSR performed poorly in the presence of self-similar traffic at high mobility especially in terms of data packet delivery ratio, routing overhead and delay. As for AODV routing protocol, the results show an average performance, yet a remarkably low and stable end-to-end delay.

/pdf/performance-analysis-of-manet-routing-protocols-in-the-1bxp256ckd.pdf

Performance Analysis of MANET Routing Protocols in the Presence of Self-Similar Traffic

Analytical models of deterministic routing in wormhole-routed k-ary n-cubes have widely been reported in the literature. Although many fully adaptive routing algorithms have been proposed to overcome the performance limitations of deterministic routing, there have been hardly any studies that describe analytical models for these algorithms. This paper proposes a new analytical model for obtaining latency measures in high-radix k-ary n-cubes with fully adaptive routing, based on Duato's algorithm (1998). The validity of the model is demonstrated by comparing analytical results with those obtained through simulation experiments.

A performance model for Duato's fully adaptive routing algorithm in k-ary n-cubes

Broadcasting in Mobile Ad Hoc Networks (MANETs) is a fundamental data dissemination mechanism with a number of important applications in, e.g., route discovery, address resolution. However, broadcasting induces what is known as the “broadcast storm problem” which causes severe degradation in network performance due to excessive redundant retransmission, collision, and contention. Broadcasting in MANETs has traditionally been based on flooding, which simply swamps the network with large number of rebroadcast messages in order to reach all network nodes. Although probabilistic flooding has been one of the earliest suggested schemes to broadcasting, there has not been so far any attempt to analyse its performance behaviour in a MANET environment. In an effort to fill this gap, this paper investigates using extensive ns-2 simulations the effects of a number of important system parameters in a typical MANET, including node speed, pause time, traffic load, and node density on the performance of probabilistic flooding. The results reveal that most of these parameters have a critical impact on the reachability and the number of saved rebroadcast messages achieved by probabilistic flooding.

Performance Analysis of Adjusted Probabilistic Broadcasting in Mobile Ad Hoc Networks

Many recent studies have convincingly demonstrated that network traffic exhibits a noticeable self-similar nature, which has a considerable impact on queuing performance. However, the networks used in current multicomputers have been primarily designed and analyzed under the assumption of the traditional Poisson arrival process, which is inherently unable to capture traffic self-similarity. Consequently, it is crucial to reexamine the performance properties of multicomputer networks in the context of more realistic traffic models before practical implementations show their potential faults. In an effort toward this end, we propose the first analytical model for wormhole-switched k-ary n-cubes in the presence of self-similar traffic. Simulation experiments demonstrate that the proposed model exhibits a good degree of accuracy for various system sizes and under different operating conditions. The analytical model is then used to investigate the implications of traffic self-similarity on network performance. We reveal that the network suffers considerable performance degradation when subjected to self-similar traffic, stressing the great need for improving network performance to ensure efficient support for this type of traffic.

A performance model for wormhole-switched interconnection networks under self-similar traffic

Networks on chip (NoC) emerged as a promising alternative to bus-based interconnect networks to handle the increasing communication requirements of the large systems on chip. Employing an appropriate topology for a NoC is of high importance mainly because it typically trade-offs between cross-cutting concerns such as performance and cost. The spidergon topology is a novel architecture which is proposed recently for NoC domain. The objective of the spidergon NoC has been addressing the need for a fixed and optimized topology to realize cost effective multi-processor SoC (MPSoC) development [7]. In this paper we analyze the traffic behavior in the spidergon scheme and present an analytical evaluation of the average message latency in the architecture. We prove the validity of the analysis by comparing the model against the results produced by a discrete- event simulator.

/pdf/an-analytical-performance-model-for-the-spidergon-noc-1qyrv6wgtq.pdf

Mohamed Ould-Khaoua

Papers

Performance Analysis of MANET Routing Protocols in the Presence of Self-Similar Traffic

A performance model for Duato's fully adaptive routing algorithm in k-ary n-cubes

Performance Analysis of Adjusted Probabilistic Broadcasting in Mobile Ad Hoc Networks

A performance model for wormhole-switched interconnection networks under self-similar traffic

An Analytical Performance Model for the Spidergon NoC