<p>This work address the adding, removing and upgrading of network elements in a computer network at run-time. This is already accomplished by Sun Microsystems Jini architecture, but we have investigated if it is possible to create a maintenance system that can handle this, using CORBA. We also want the manual intervention to be minimal. We have discovered that it is possible to create such a system, using CORBA, and that this solution also can handle upgrading a network element at run-time. This report outlines the design of this system, realizing automatic run-time network maintenance.</p>

abstract: This research develops heuristics to manage both mandatory and optional network capacity reductions to better serve the network flows. The main application discussed relates to transportation networks, and flow cost relates to travel cost of users of the network. Temporary mandatory capacity reductions are required by maintenance activities. The objective of managing maintenance activities and the attendant temporary network capacity reductions is to schedule the required segment closures so that all maintenance work can be completed on time, and the total flow cost over the maintenance period is minimized for different types of flows. The goal of optional network capacity reduction is to selectively reduce the capacity of some links to improve the overall efficiency of user-optimized flows, where each traveler takes the route that minimizes the traveler’s trip cost. In this dissertation, both managing mandatory and optional network capacity reductions are addressed with the consideration of network-wide flow diversions due to changed link capacities. This research first investigates the maintenance scheduling in transportation networks with service vehicles (e.g., truck fleets and passenger transport fleets), where these vehicles are assumed to take the system-optimized routes that minimize the total travel cost of the fleet. This problem is solved with the randomized fixed-and-optimize heuristic developed. This research also investigates the maintenance scheduling in networks with multi-modal traffic that consists of (1) regular human-driven cars with user-optimized routing and (2) self-driving vehicles with system-optimized routing. An iterative mixed flow assignment algorithm is developed to obtain the multi-modal traffic assignment resulting from a maintenance schedule. The genetic algorithm with multi-point crossover is applied to obtain a good schedule. Based on the Braess’ paradox that removing some links may alleviate the congestion of user-optimized flows, this research generalizes the Braess’ paradox to reduce the capacity of selected links to improve the efficiency of the resultant user-optimized flows. A heuristic is developed to identify links to reduce capacity, and the corresponding capacity reduction amounts, to get more efficient total flows. Experiments on real networks demonstrate the generalized Braess’ paradox exists in reality, and the heuristic developed solves real-world test cases even when commercial solvers fail. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2017

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-06-01T16:58:59Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Flavio Trojan TESE.pdf: 2776137 bytes, checksum: 55e95b9ae53f2fce24e0caa97923ffeb (MD5) / Made available in DSpace on 2017-06-01T16:58:59Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Flavio Trojan TESE.pdf: 2776137 bytes, checksum: 55e95b9ae53f2fce24e0caa97923ffeb (MD5) Previous issue date: 2012-04-25 / Por conta das dificuldades implícitas ao processo decisório em grupo e dos problemas correlatos no setor de abastecimento de água, tais como: perdas físicas e econômicas, uso incorreto da água e custos com manutenção, fica evidente a necessidade de elaboração de pesquisas e estudos, envolvendo métodos para apoiar decisões, a fim de diminuir desperdícios de água e sua exploração desnecessária. Este trabalho tem como objetivo auxiliar nas tomadas de decisões de problemas emergentes no setor de manutenção de redes de distribuição de água. Dois dos principais problemas do setor são abordados. O primeiro deles explora a classificação de áreas de medição de vazão, conforme sua criticidade, para auxiliar no controle de perdas de água. Para este problema é proposto um modelo multicritério para classificação de áreas críticas de medição de vazão, baseado no método ELECTRE TRI, sendo sua estrutura quantitativa com o levantamento dos dados feito por meio de um sistema automatizado. O segundo problema abordado baseia-se na classificação realizada no modelo anterior e explora quais alternativas de manutenção são potencialmente eficazes para serem implementadas nas classes, de acordo com a visão de um grupo de decisores, para reduzir perdas de água e custos de manutenção. Assim, este segundo modelo trata da problemática de ordenação de alternativas de manutenção por meio de uma tomada de decisão em grupo, sendo baseado no método ELECTRE II, a fim de apoiar as ordenações individuais numa primeira fase, e posteriormente, no método COPELAND, para agregação das preferências do grupo. Estes modelos consideram aspectos subjetivos e objetivos ao mesmo tempo, a fim de fornecer como resultado aos decisores uma visão mais clara e global sobre quais alternativas poderão atender os múltiplos objetivos estabelecidos pela organização, decorrentes das preferências de um grupo de decisores de diferentes áreas. Com os modelos desenvolvidos é possível conhecer as áreas críticas de uma rede de distribuição de água para apoiar a gestão da manutenção e priorizar as alternativas potenciais para redução das perdas de água. / Because of the difficulties implied in the group decision making process and related problems in the sector of water supply, such as: physical and economic losses, incorrect use of water and maintenance costs, the need for research and studies developing methods to support the decisions, reducing unnecessary exploitation and waste becomes evident. This work aims to assist decision-making for arising problems in the maintenance area of the water networks. Two major problems in the sector are addressed. The first explores the correct classification of critical areas of flow measurement, classifying them according to their priorities to help control water loss. For this problem, a multicriteria model that deals with the classification of critical flow measurement is proposed, it is based on the ELECTRE TRI method, presenting an overview of its structure with quantitative data collection through an automated system. The second problem addressed is based on the classification carried out in the previous model and explores which maintenance alternatives are potentially effective to be implemented in priority classes according to the group of decision makers point of view to reduce water losses. The following multicriteria model proposes that a group of decision makers sort out maintenance and investment alternatives for areas previously classified according to their criticality. Thus, this second model deals with the problem of sorting out maintenance alternatives through group decision making, initially based on ELECTRE II, to support individual ordinations, and subsequently, on the Copeland method, for group preference aggregation. These models consider subjective and objective aspects simultaneously, in order to provide the decision makers with a clearer and comprehensive view in which the alternatives can attend the multiple objectives set by companies, arising from the preferences of a group of decision makers from different areas. With the models developed, it is possible to recognize priority classes to support the maintenance management, where the critical points are, and the major potential alternatives to solve maintenance problems and water loss in these classes through aggregation of preferences and global ordering.

This work address the adding, removing and upgrading of network elements in a computer network at run-time. This is already accomplished by Sun Microsystems Jini architecture, but we have investigated if it is possible to create a maintenance system that can handle this, using CORBA. We also want the manual intervention to be minimal. We have discovered that it is possible to create such a system, using CORBA, and that this solution also can handle upgrading a network element at run-time. This report outlines the design of this system, realizing automatic run-time network maintenance.

This diploma thesis deals with the proposal and the maintenance of Ethernet computer networks in the Department of Telecommunication property in Brno. There is a description of communication line types used in LAN computer networks in the first parts of the work. Their advantages and disadvantages are introduced too. Further there is an existing situation of the computer network on the third and the fourth floor of the Department of Telecommunication building documented. This documentation includes a design and a list of used components. The existing computer network has some minor inadequacies that were taken into consideration in the new proposal. There is a completely elaborate documentation of the new proposed network on the third and the fourth floor that contains a detailed placement and a single component configuration including their description. This documentation should significantly contribute to more effective network maintenance in the future. The computer network maintenance does not contain only servers, printers or workstations. It's also necessary to consider network parts that are not so perceptible for common users. That means single segments of computer networks with its active devices. A web based application for the effective computer network maintenance is proposed and described in this work too. The application allows administrator to keep a well-arrange view of the single network segments. All network related information is saved into a database that can help with a solution of later occurred problems.

Thesis. (M. Tech. (Faculty of Engineering and Technology, Dept. of Civil Engineering))--Vaal University of Technology, 2011 / In the past thirty years there has been a rapid deterioration of the road network in South Africa. As an attempt to address this challenge, a study was conducted on R34 between Vrede and Bothmas Pass Border. The aim of the study was to develop a pavement management system for road network maintenance to serve as a decision support tool to assist to improve the efficiency of making decisions, provide feedback as to the consequences of these decisions, ensure consistency of decisions made at different levels and improve the effectiveness of all decisions in terms of efficiency of results. The study focused on developing and testing pavement management system for road network maintenance. Consequently, visual condition inspections, non-destructive and semi-destructive tests were conducted on the field, data acquired, processed and analysed in accordance with guidelines stipulated in the Draft Technical Recommendations for Highways (TRH) 22 in order to draw conclusions. The data acquired included the surfacing assessments, structural assessments, functional assessments, traffic surveys, riding quality, falling weight deflectometer, mechanical rutting, material investigations and dynamic cone penetration. After analysis of the data, visual condition index was then calculated to be 40%. Visual condition index was then used to determine the action required towards rehabilitating the road. After consultation with guidelines contained in the TRH22, it was concluded that the pavement treatment needed for the road was Rehabilitation. It was then concluded that PMS developed would provide key performance indicators to assist with decision support system and that it is also suitable for road network applications ranging from national roads, provincial roads, regional or district arterial and collector / distributor networks in SA. The municipalities and other road maintenance agencies were then recommended to utilise the “easy to use” developed pavement management system as a decision support tool in their maintenance programmes.

Nous étudions le problème de maintenir une distribution donnée de graphes aléatoires après une séquence arbitraire d’insertions et de suppressions de sommets. Dans l’objectif de modéliser l’évolution de réseaux logiques dynamiques,nous travaillons dans un modèle local où l’accès à la liste des sommets est restreint. À la place, nous faisons l’hypothèse d’un accès à une primitive globale qui retourne un sommet aléatoire, choisi uniformément dans l’ensemble total des sommets. Le problème de maintenance a été exploré sur plusieurs modèles simples de graphes aléatoires (graphes d’Erdos–Rényi, graphes basés sur le modèle par paires, graphes k-sortants uniformes). Pour chacun des modèles, un ou plusieurs algorithmes pour la tâche de maintenance ont été décris et analysés ; les plus élaborés de ces algorithmes sont asymptotiquement optimaux. Le problème de maintenance soulève plusieurs problèmes de simulation liés à notre contexte distribué. Nous nous sommes intéressé en particulier à la maintenabilité de distributions de graphes et à la simulabilité de familles de distributions de probabilité sur les entiers, dans le modèle d’aléa présenté.Une attention particulière a été portée sur la simulation efficace de lois spécifiques nous intéressant (certaines lois binomiales). Cette dernière a pu être obtenue en exploitant les propriétés d’un nouvel arbre de génération pour les permutations, que nous avons introduit. / We study the problem of maintaining a given distribution of randomgraphs under an arbitrary sequence of vertex insertions and deletions. Keeping inmind our objective to model the evolution of dynamic logical networks, we work ina local model where we do not have direct access to the list of all vertices. Instead,we assume access to a global primitive that returns a random vertex, chosen uniformlyfrom the whole vertex set. The maintenance problem has been explored onseveral simple random graph models (Erdos–Rényi random graphs, pairing modelbased random graphs, uniform k-out graphs). For each model, one or several updatealgorithms for the maintenance task have been described and analyzed ; the mostelaborate of them are asymptically optimal. The maintenance task rise several simulationissues linked to our distributed context. In particular, we have focused onmaintenability of random graph distributions and simulability of families of probabilitydistributions over integers in our local random model. Special attention hasbeen paid to efficient simulation of particular distributions we were interested in(certain binomial distributions). The latter has been obtained through the use ofproperties of a new generation tree for permutations, which has been introducedalong the way

The thesis is dealing with creating and implementation of helpdesk system with diagnostics (feedback) for The Best Network Solution, the IT outsourcing company, serving for maintenance theirs computer networks, equipment and end customers support.