Dynamic management and restoration of virtual paths in broadband networks based on distributed software agents

La gestió de xarxes és un camp molt ampli i inclou molts aspectes diferents. Aquesta tesi doctoral està centrada en la gestió dels recursos en les xarxes de banda ampla que disposin de mecanismes per fer reserves de recursos, com per exemple Asynchronous Transfer Mode (ATM) o Multi-Protocol Label Switching (MPLS). Es poden establir xarxes lògiques utilitzant els Virtual Paths (VP) d'ATM o els Label Switched Paths (LSP) de MPLS, als que anomenem genèricament camins lògics. Els usuaris de la xarxa utilitzen doncs aquests camins lògics, que poden tenir recursos assignats, per establir les seves comunicacions. A més, els camins lògics són molt flexibles i les seves característiques es poden canviar dinàmicament. Aquest treball, se centra, en particular, en la gestió dinàmica d'aquesta xarxa lògica per tal de maximitzar-ne el rendiment i adaptar-la a les connexions ofertes. En aquest escenari, hi ha diversos mecanismes que poden afectar i modificar les característiques dels camins lògics (ample de banda, ruta, etc.). Aquests mecanismes inclouen els de balanceig de la càrrega (reassignació d'ample de banda i reencaminament) i els de restauració de fallades (ús de camins lògics de backup). Aquests dos mecanismes poden modificar la xarxa lògica i gestionar els recursos (ample de banda) dels enllaços físics. Per tant, existeix la necessitat de coordinar aquests mecanismes per evitar possibles interferències. La gestió de recursos convencional que fa ús de la xarxa lògica, recalcula periòdicament (per exemple cada hora o cada dia) tota la xarxa lògica d'una forma centralitzada. Això introdueix el problema que els reajustaments de la xarxa lògica no es realitzen en el moment en què realment hi ha problemes. D'altra banda també introdueix la necessitat de mantenir una visió centralitzada de tota la xarxa. En aquesta tesi, es proposa una arquitectura distribuïda basada en un sistema multi agent. L'objectiu principal d'aquesta arquitectura és realitzar de forma conjunta i coordinada la gestió de recursos a nivell de xarxa lògica, integrant els mecanismes de reajustament d'ample de banda amb els mecanismes de restauració preplanejada, inclosa la gestió de l'ample de banda reservada per a la restauració. Es proposa que aquesta gestió es porti a terme d'una forma contínua, no periòdica, actuant quan es detecta el problema (quan un camí lògic està congestionat, o sigui, quan està rebutjant peticions de connexió dels usuaris perquè està saturat) i d'una forma completament distribuïda, o sigui, sense mantenir una visió global de la xarxa. Així doncs, l'arquitectura proposada realitza petits rearranjaments a la xarxa lògica adaptant-la d'una forma contínua a la demanda dels usuaris. L'arquitectura proposada també té en consideració altres objectius com l'escalabilitat, la modularitat, la robustesa, la flexibilitat i la simplicitat. El sistema multi agent proposat està estructurat en dues capes d'agents: els agents de monitorització (M) i els de rendiment (P). Aquests agents estan situats en els diferents nodes de la xarxa: hi ha un agent P i diversos agents M a cada node; aquests últims subordinats als P. Per tant l'arquitectura proposada es pot veure com una jerarquia d'agents. Cada agent és responsable de monitoritzar i controlar els recursos als que està assignat. S'han realitzat diferents experiments utilitzant un simulador distribuït a nivell de connexió proposat per nosaltres mateixos. Els resultats mostren que l'arquitectura proposada és capaç de realitzar les tasques assignades de detecció de la congestió, reassignació dinàmica d'ample de banda i reencaminament d'una forma coordinada amb els mecanismes de restauració preplanejada i gestió de l'ample de banda reservat per la restauració. L'arquitectura distribuïda ofereix una escalabilitat i robustesa acceptables gràcies a la seva flexibilitat i modularitat.

A data collection case study supporting requirements oriented prediction and management in software developments

Consider the statement "this project should cost X and has risk of Y". Such statements are used daily in industry as the basis for making decisions. The work reported here is part of a study aimed at providing a rational and pragmatic basis for such statements. Of particular interest are predictions made in the requirements and early phases of projects. A preliminary model has been constructed using Bayesian Belief Networks and in support of this, a programme to collect and study data during the execution of various software development projects commenced in May 2002. The data collection programme is undertaken under the constraints of a commercial industrial regime of multiple concurrent small to medium scale software development projects. Guided by pragmatism, the work is predicated on the use of data that can be collected readily by project managers; including expert judgements, effort, elapsed times and metrics collected within each project.

Digital infrastructure and changing practices in engineering design

New skills are needed to compete, as integrated software solutions provide a digital infrastructure for projects. This changes the practice of information management and engineering design on next generation projects.

Software warehouse: its design management and application

To have an effective and efficient mechanism to store, manage and utilize software sources is essential to the automation of software engineering. The paper presents an innovative approach in managing software resources using software warehouse where software assets are systematically accumulated, deposited, retrieved, packaged, managed and utilized, driven by data-mining and OLAP technologies. The results lead to streamlined high efficient software development process and enhance the productivity in response to modern challenges of the design and development of software applications.

Security management : modelling critical infrastructure

Secure management of Australia's commercial critical infrastructure presents ongoing challenges to owners and the government. Currently a high-level iriformation sharing collaboration between the government and business manages complex security issues, but critical irifrastructure protection also lacks a scalable model exhibiting the overall structure of critical infrastructure at various levels, sectors and sub-sectors. This research builds on the work of Marasea and Warren (2003) to establish a representative model of Australia's critical irifrastructure; discusses the boundaries between critical infrastructures, and considers the existence andpotential irifluence ofcritical irifrastructure relationships.

Assessment management using software

Web based learning is providing new and innovative environments to facilitate the delivery of course material to increasing numbers students, but most of the effort is centered around the presentation of the learning material and creating environments where student interact with this material and each other. Despite the changes the web based learning environments have delivered, little attention has been given to improving the management and process of assessment. This paper introduces a new software application designed to take advantage of the web based environments and addresses the management overheads associated with assessment whilst improving the feedback to students. Initial investigations indicate significant benefits can be achieved by using software to manage the assessment process. A detailed description of the software is provided and two case studies presented that highlight the software's application and confirmed benefits when used to conduct and manage assessments.

Information security, cyber crime, and infrastructure protection : information security management within Australian healthcare organisations

Information security is now recognised as critical factor within the healthcare industry. With the gradual move from paper -based to electronic information there is an even greater need for protection. However, financial and operational constraints often exist which influence the practicality of developing a secure system. A new baseline security standard, the Health Information Security Management Implementation Guide, has been drafted which applies specifically to the unique information security requirements of the healthcare industry. The aim of this paper is to look at the effectiveness of the health information security standard and the development of information security within the Australian healthcare industry.

Australian commercial-critical infrastructure management protection

Secure management of Australia's commercial critical infrastructure presents ongoing challenges to owners and the government. Although managed via a high-level information sharing collaboration of government and business, critical infrastructure protection is further complicated by the lack of a lower-level scalable model exhibiting its various levels, sectors and sub-sectors. This research builds on the work of Marasea (2003) to establish a descriptive critical infrastructure model and also considers the influence and proposed modelling of critical infrastructure dependency inter-relationships.

Evolutionary multiobjective optimization in engineering management: an empirical application in infrastructure systems

Generally multiple objectives exist in transportation infrastructure management, such as minimum cost and maximum service capacity. Although solution methoak of multiobjective optimization problems have undergone continual development over the part several decades, the methods available to date are not particularly robust, and none of them perform well on the broad classes. Because genetic algorithms work with apopulation ofpoints, they can capture a number of solutions simultaneously, and easily incorporate the concept of a Pareto optimal set in their optimization process. In this paper, a genetic algorithm is modified to deal with an empirical application for the rehabilitation planning of bridge decks, at a network level, by minimizing the rehabilitation cost and deterioration degree simultaneously.

Critical infrastructure protection, modelling and management: an Australian commercial case study

This research extends upon the previous work of Pye and Warren (2005) and presents a refinement of the previously proposed critical infrastructure model to enhance further our understanding and apprecication of where the likely inter-play and existance of dependency relationships between infrastructures coexist.

These associations are presented as a number of linkages that exist within each sector of Australia'a critical infrastructure, which is then extended further to the modelling of dependency inter-relationships that exist between critical infrastructures itilising Petri Nets.  The recognition and identification of such reliance relationships between critical infrastructures is necessary to allow both infrastructure owners and the government to identify and effectively manage and maintain the security, stability and availability of their particular critical infrastructure against potential scenario driven effects.  These issues are reflected within a case study as modelled using the Petri Net approach to encapsulate the issues of reliance relationships by drawing upon an Australian commercial case study.