Hesham El-Rewini

Integration of mobile ad hoc networks and the Internet using mobile gateways

Summary form only given. Mobile ad hoc networks (MANET) and the Internet exhibit differences in their network architecture. These differences concern the various sorts of assumptions imposed not only on the structure and topology of the underlying networks, but also on communication patterns of mobile nodes in both networks. Integrating MANET and the Internet into a hybrid network is a challenging problem due to these differences. We propose a three-layer approach that uses both mobile IP and dynamic destination-sequenced distance vector (DSDV) to integrate these two types of networks into a hybrid environment, in order to provide MANET nodes with Internet connectivity and access to the Internet resources. Our approach is based on the use of mobile gateways as an interface between MANET and the Internet. These mobile gateways can use mobile IP when they communicate with the Internet and DSDV when they interact with MANET. We also show the results of several simulation experiments that were conducted to study the integrated environment.

Autonomic Power & Performance Management for Large-Scale Data Centers

With the rapid growth of servers and applications spurred by the Internet, the power consumption of servers has become critically important and must be efficiently managed. High energy consumption also translates into excessive heat dissipation which in turn, increases cooling costs and causes servers to become more prone to failure. This paper presents a theoretical and experimental framework and general methodology for hierarchical autonomic power & performance management in high performance distributed data centers. We optimize for power & performance (performance/watt) at each level of the hierarchy while maintaining scalability. We adopt mathematically-rigorous optimization approach to provide the application with the required amount of memory at runtime. This enables us to transition the unused memory capacity to a low power state. Our experimental results show a maximum performance/watt improvement of 88.48% compared to traditional techniques. We also present preliminary results of using game theory to optimize performance/watt at the cluster level of a data center. Our cooperative technique reduces the power consumption by 65% when compared to traditional techniques (min-min heuristic).

Optimal and approximate approaches for deployment of heterogeneous sensing devices

A modeling framework for the problem of deploying a set of heterogeneous sensors in a field with time-varying differential surveillance requirements is presented. The problem is formulated as mixed integer mathematical program with the objective to maximize coverage of a given field. Two metaheuristics are used to solve this problem. The first heuristic adopts a genetic algorithm (GA) approach while the second heuristic implements a simulated annealing (SA) algorithm. A set of experiments is used to illustrate the capabilities of the developed models and to compare their performance. The experiments investigate the effect of parameters related to the size of the sensor deployment problem including number of deployed sensors, size of the monitored field, and length of the monitoring horizon. They also examine several endogenous parameters related to the developed GA and SA algorithms.

VHARP: Virtual Home Agent Reliability Protocol for Mobile IPv6 based Networks

Mobile IPv6 is an enabling platform for creating IP mobility in the evolution path towards next generation service offerings. Current specification of mobile IPv6 does not provide reliability in the network and there are other problems associated with it. In this paper, we introduce virtual home agent reliability protocol as a complete system architecture and extension to mobile IPv6 that supports reliability and offers solution to the reliability problems associated with mobile IPv6. We also present the results of several experiments to assess the performance of our solution. The main advantages of our protocol over other protocols are: reliable mobile IPv6 operation, transparent failure detection and recovery mechanisms, reduced message exchange, no service interruption in mobile applications, reduced workload, secure data transfer, improved overall system and application performance

Using hybrid selection schemes to support QoS when providing multihop wireless Internet access to mobile ad hoc networks

The quality of service (QoS) of wireless Internet access that could be provided to multihop wireless networks, so-called mobile ad hoc networks (MANETs), is highly dependent on the quality of the design of the intermediate facility that will integrate MANET and the Internet. This facility is equipped with a hybrid mechanism being able to fulfill the working requirements of MANET and the Internet so that it can connect to either one of these orthogonal network architectures. The architecture that we propose in order to provide MANET nodes with Internet access utilizes fixed gateways (or access points) and exploits the mobility capability of additional mobile ones. Since Internet access to MANET nodes is provided through mobile gateways, the quality of such service depends on the selection procedure used by MANET nodes to choose the most convenient mobile gateways and register with. In this paper, we suggest to use a hybrid criterion based on the weighted sum of the Euclidean distance between MANET nodes and mobile gateways, and the load of mobile gateways, defined as the number of MANET nodes currently registered with them. Moreover, the sum of the weights is normalized to one, where each weight measures the level of interest of the corresponding criterion in the hybrid one. Simulation results show that the hybrid criterion has an impact on the quality of wireless Internet access service depending on the level of interest assigned to each of the Euclidean distance and load criteria in the weighted sum.

Adaptive Constraint-Based Multi-Objective Routing for Wireless Sensor Networks

Wireless sensor networks (WSN) is a rising technology that promises to bridge the gap between the physical and digital worlds. Being limited in processing power, memory space, communication range and energy resources as well as unlikely prone to human intervention, WSN communications put extra challenges on the routing task. In addition, the wide variety of sensor applications often requires that multiple conflicting objectives be satisfied in the routing task. We propose a framework for routing in WSN that is adaptive, constraint-based, multi-objective and which is also solely dependant on localized knowledge.

Grid resource allocation and task scheduling for resource intensive applications

Evolution of grid has drawn attention from various resource intensive applications addressing domains of bio-informatics, astrology and multimedia, to name a few. Image analysis applications in both bio-sciences and astrophysics are explicitly built in modular fashion to exploit the potential offered by grid. In this paper, we present a framework for resource allocation and task scheduling, MARS (management architecture for resource services), which efficiently allocates resources for such resource intensive applications which can be represented as task interaction graph (TIG), while keeping makespan as minimum as the current state of resources in grid allows. Simulation experiments with MARS show a considerable improvement in job completion time and host utilization over traditional resource management and scheduling algorithms for grid

Efficient dynamic load balancing for multiple home agents in Mobile IPv6 based networks

The current specification of Mobile IPv6 does not provide load balancing among multiple home agents on the home link. In this paper, we introduce a load balancing mechanism as an extension to Mobile IPv6 that provides an efficient dynamic load balancing among multiple home agents. It takes into account acceptable packet forwarding rate for each home agent, with the aim of reducing and preventing traffic bottlenecks at the home agent. The advantages of our load balancing mechanism over other protocols are transparent load balancing, reduced message overhead over the air interface, fair load distribution among the home agents, no service interruption in the upper layer applications during load balancing, efficient resource utilization, and increased overall system performance.

On the use of meta-heuristics to increase the efficiency of online grid workflow scheduling algorithms

The competitiveness of online algorithms is measured based on the correctness of the results produced and processing time efficiency. Traditionally evolutionary algorithms are not favored in online paradigms because of the large number of iterations involved in the algorithm which translates directly into processing time overhead. In this paper we describe MARS (Management Architecture for Resource Services) online scheduling algorithm which uses Simulated Annealing and concepts from Tabu Search to drastically decrease the processing time of the algorithm. The paper outlines the concepts behind MARS, the components involved and scheduling methodology used. In addition we also identify the time consuming bottlenecks in the performance of the system and how evolutionary algorithms help us soar past them.

SensDep: a design tool for the deployment of heterogeneous sensing devices

In this paper, we introduce SensDep as a software design tool that incorporates several solution strategies to optimize sensor networks cost and coverage. The tool helps the designer answer many what-if questions that usually arise in the design of surveillance operations networks. Also, it considers several operation capabilities for the sensing devices including reliability, mobility, transfer cost, sensors cost, lifespan and power self scheduling in addition to the environment parameters during the deployment process. Moreover, it provides the designer the optimal deployment scheme for small size designs using mathematical programming. It also provides near optimal schemes for large scale designs using a set of heuristic solutions. A set of experiments is conducted to test the tool capabilities for different design settings. Several design scenarios are presented to illustrate how the tool can be utilized