CREW SCHEDULING PROBLEMS IN THE AIRLINE INDUSTRY

Master'sMASTER OF SCIENC

ALGORITHMS FOR RECONFIGURATION PROBLEMS IN VLSI/WSI ARRAYS

Ph.DDOCTOR OF PHILOSOPH

The general message ferry route (MFR∗) problem and the An-Improved-Route (AIR) scheme

In existing studies of message ferry (MF) schemes in wireless ad hoc networks, routes for message ferries are often adopted from the solutions of the Traveling Salesman Problem (TSP) and its variants. In such existing solutions, a message ferry route is often assumed to be a simple cycle which has no repeated vertices nor edges. In this paper, we consider a more general case, where the route is a closed walk. In doing so, we generalize the massage ferry route (MFR) problem as the MFR∗ problem, and propose the An-Improved-Route (AIR) scheme to construct routes for the ferry. Simulation proves that the AIR scheme effectively reduces the delay of the MF schemes. Moreover, our studies and schemes in this paper can easily be extended to operation research problems in other related fields, such as transportation and traffic coordination etc

Throughput optimal energy neutral management for energy harvesting wireless sensor networks

Energy harvesting techniques have enabled the provisioning of alternative energy sources beside the conventional one which is typically provided by the batteries. Using such harvesting techniques together with proper energy management mechanisms, a Energy Neutral state can be achieved so that desired performance level can be supported perpetually. Existing energy neutral management mechanisms rely on the prediction of the amount of energy that can be harvested in the future. Such mechanisms suffer from the time consuming prediction processes and great fluctuations in the actual implementations. Hence, in this paper we propose real time adaptive energy management policies that enable energy neutral management based solely on observed information in the past instead of predicting the amount of energy that can be harvested in the future. We will show that these policies are throughput optimal in the sense that we are able to ensure that the data queue of each sensor node remain stable when the largest possible data rate is applied under different channel capacity scenarios. We also propose an energy harvest-store(use) method to reduce the energy losses caused by storing energy in non ideal energy buffers. Simulation studies show that our proposed throughput optimal policies and harvest-store(use) method are indeed able to improve the overall throughput as compared to existing schemes

A Flexible Wavelength Converter Placement Scheme for Guaranteed Wavelength Usage

Abstract — Wavelength is one of the most important resource

Virtual environment based system for assisting object-oriented software development

In this project, we aimed to develop a real-time Collaborative Virtual Environment based CASE tool that provides a 3D multi-user collaborative object modeling environment and automatic object-class abstraction facility for assisting Object-Oriented software development.RG 20/9

Performance Evaluation of Routing Protocols on the Reference Region Group Mobility Model for MANET Abstract

Group mobility is prevalent in many mobile ad hoc network (MANET) applications, such as disaster recovery, military operations, searching and rescue activities. Group partition, as an inherent phenomenon in group mobility, may occur when mobile nodes move in diverse mobility patterns and it causes the network to be partitioned into disconnected components. It may result in severe link disconnections, which interrupts network communications. To address this concern, we proposed a novel group mobility model in this paper, namely the Reference Region Group Mobility model, which can be used to mimic group operations in MA-NETs, i.e. group partitions and mergers. Based on this model, a comprehensive study on the impact of group partitions to the performance of network routing protocols are carried out by evaluating two well-known routing protocols, namely the Ad Hoc On-demand Distance Vector Routing protocol (AODV) and the Dynamic Source Routing protocol (DSR). The simulation results reflect that group partitions have a significant impact to the performance of network routing protocols