Adel Ben Mnaouer

Throughput and delay analysis of the IEEE 802.11e EDCA saturation

In this paper, we introduce a simple model for the enhanced distributed channel access (EDCA) mechanism under saturation conditions. This model captures the operation of the AIFS (arbitration inter-frame space) and contention window differentiation of the EDCA mechanism. Using this model, we analyze the throughput and delay performance of EDCA. The results of our analytical model are then verified using simulations.

OPHMR: An Optimized Polymorphic Hybrid Multicast Routing Protocol for MANET

We propose in this paper an optimized, polymorphic, hybrid multicast routing protocol for MANET. This new polymorphic protocol attempts to benefit from the high efficiency of proactive behavior (in terms of quicker response to transmission requests) and the limited network traffic overhead of the reactive behavior, while being power, mobility, and vicinity-density (in terms of number of neighbor nodes per specified area around a mobile node) aware. The proposed protocol is based on the principle of adaptability and multibehavioral modes of operations. It is able to change behavior in different situations in order to improve certain metrics like maximizing battery life, reducing communication delays, improving deliverability, etc. The protocol is augmented by an optimization scheme, adapted from the one proposed for the optimized link state routing protocol (OLSR) in which only selected neighbor nodes propagate control packets to reduce the amount of control overhead. Extensive simulations and comparison to peer protocols demonstrated the effectiveness of the proposed protocol in improving performance and in extending battery power longevity

A generic framework for rapid application development of mobile Web services with dynamic workflow management

This paper proposes a rapid application development framework for creating mobile Web services supported by a dynamic workflow engine that displays an interface depending on a specified workflow. The model leverages on existing reference architectures, and open source standards, to create an interoperable, flexible and easy to implement development framework for creating mobile Web services. Our model is generic in nature to allow the development of Web services for a diverse range of scenarios. The dynamic workflow engine, residing on the client allows for easy updates on the server, and again caters to a diverse set of applications on the client side. The rapid application development model for mobile Web services proposed in this paper has been applied to a field service solution workflow and details on the implementation at both the client and the server are provided.

A new delay-constrained algorithm for multicast routing tree construction

New multimedia applications provide guaranteed end-to-end quality of service (QoS) and have stringent constraints on delay, delay-jitter, bandwidth, cost, etc. The main task of QoS routing is to find a route in the network, with sufficient resources to satisfy the constraints. Most multicast routing algorithms are not fast enough for large-scale networks and where the source node uses global cost information to construct a multicast tree. We propose a fast and simple heuristic algorithm (EPDT) for delay-constrained routing problem for multicast tree construction. This algorithm uses a greedy strategy based on shortest-path and minimal spanning trees. It combines the minimum cost and the minimum radius objectives by combining respectively optimal Prims and Dijkstras algorithms. It biases routes through destinations. Besides, it uses cost information only from neighbouring nodes as it proceeds, which makes it more practical, from an implementation point of view. Copyright

A new polymorphic multicast routing protocol for MANET

We propose in this paper, a polymorphic, hybrid multicast routing protocol for MANET (mobile ad hoc networks). This new polymorphic protocol attempts to take benefit of the high efficiency of proactive behavior and the low cost of network traffic of the reactive behavior. The protocol is based on the principle of adaptability and multi-behavioral modes of operations. The proposed protocol is able to change behavior in different situations in order to improve certain metrics like the battery power. Extensive simulations demonstrated the effectiveness of the proposed protocol in improving performance and in extending battery power longevity.

An Optimized Polymorphic Hybrid Multicast Routing Protocol (OPHMR) for Ad Hoc Networks

We propose in this paper, an optimized, polymorphic, hybrid multicast routing protocol for MANET. The protocol proposed is based on the principle of adaptability and multi-behayioral modes of operations. It is able to change behavior in different situations in order to improve certain metrics like maximizing battery life, reducing communication delays, improving deliverability, etc. This new polymorphic protocol attempts to benefit of the high efficiency of proactive behavior and the low cost of network traffic of the reactive behavior, while being power, mobility and vicinity density aware. The protocol is augmented by an optimization scheme, adapted from the one proposed for the optimized link state routing protocol (OLSR) in which only selected neighbor nodes propagate control packets to reduce the amount of control overhead. Extensive simulations and comparison to peer protocols demonstrated the effectiveness of the proposed protocol in improving performance and in extending battery power longevity.

Effective scheduling of local interactive processes and parallel processes in a non-dedicated cluster environment

This paper presents a performance evaluation of the interactions between local sequential processes running on behalf of interactive applications and parallel processes running as part of an overall parallel application on a non-dedicated cluster environment. To control the interactions between the two types of processes we propose to constrain the scheduling of local interactive processes (IPs) by a measure of the maximum response time (MRT) expected by the workstation (WS) user. The measure is assumed obtained through empirical studies. We propose a mathematical model of the scheduling problem based on the usage of the MRT measure. In addition, we propose a scheduling scheme that within the MRT cycle computes the time quanta needed to satisfy the requirements of both local IPs and the parallel task process present in the system. A colored Petri net (CPN) is used to model the scheduling scheme. Simulations of the CPN model and numerical results have shown the effectiveness of the proposed scheduling scheme in allowing the parallel task to ensure a minimum speedup even in heavy-loaded situations and to maximize the speedup adaptively depending on load conditions. In addition the simulation results revealed the sensitivity of the interactions to factors such as interactive job demand, parallel job demand, and arrival rate of interactive jobs among other. Finally, simulation and analytical results have been found to agree nicely thus confirming the correctness of the proposed analytical model.

A Novel Multicast Algorithm for Collaborative Multimedia Applications in Heterogeneous Networks

Abstract In this paper, we study the problem of QoS group communication in a heterogeneous network, which consists of multiple MANETs attached to the backbone Internet. We propose a heuristic multicast algorithm called MCMA (Multi-Constrained Multicast Algorithm). MCMA is designed for solving the DVBMT (Delay-and delay Variation-Bounded Multicast Tree) problem, which has been proved to be NP-complete. The literature studies are limited to end-to-end delay bound and delay variation minimization. In this paper, we improve and extend previous well known from literature heterogeneous network algorithms to provide scalable and stable multicast services on the Internet by introducing a new Delay–Variation Estimation Scheme for heterogeneous networks. This Scheme helps the MCMA algorithm achieve better performance in terms of the multicast delay variation than some well-known algorithms. The algorithm defines QoS parameters as constraints on both delay and delay variation. Theoretical analysis is given to show the correctness of MCMA and its performance in terms of the multicast delay variation.

A new scalable multicast routing algorithm for interactive real-time applications

Quality of service (QoS) provisioning generally assumes more than one QoS measure that implies that QoS routing can be categorized as an instance of routing subject to multiple constraints: delay jitter, bandwidth, cost, etc. We study the problem of constructing multicast trees to meet the QoS requirements of real-time interactive applications where it is necessary to provide bounded delays and bounded delay variation among the source and all destinations while keeping overall cost of the multicast tree low. The main contribution of our work is a new strategy for constructing multiconstrained multicast trees. We first derive mathematically a new delay-variation estimation scheme and prove its efficiency. Thereafter, we propose a simple and competitive (in terms of running time) heuristic algorithm, for delay and delay variation constrained routing problem based on the proposed delay-variation estimation scheme and using the Extended Prim-Dijkstra tradeoffs’ algorithm. Our contribution also extends previous works in providing some properties and analyses of delay bounded paths satisfying delay variation constraints. Extensive simulation results show that our algorithm outperforms DVDMR in terms of multicast delay variation with the same time complexity as DVDMR.

An event chain notification and management system using SMS

This paper describes the design of a framework and implementation of a testbed of an event propagation and management system. These events are generated by equipment or machines in a plant. Event states are modeled using statecharts and colored Petri nets, which were used also for simulating the proposed system. In our lab test a small network is set-up, which represents a federated control system consisting of (simulated) equipment generating events, a server brokering between event producers and consumers and mobile phones, which are the consumer of events and that are used to respond to events using SMS messaging. The testbed simulates equipment or machines in a factory or plant, which under normal circumstances operate stand-alone or with minimal supervision of an operator. In case of failure, these machines require immediate response from a service engineer, as the operation of the machine within the factory or plant is mission-critical and thus demands a minimum downtime (as will be the case when there are abnormalities, failures or events). The framework was successfully tested and has been found to be a viable and affordable solution for efficient event management.