Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-03-11T18:10:20Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao JOSIAS de LIMA JUNIOR.pdf: 4252506 bytes, checksum: 714cb7aa7e2dc62943c697bd35a222ed (MD5) / Approved for entry into archive by Daniella Sodre (daniella.sodre@ufpe.br) on 2015-03-13T13:00:53Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao JOSIAS de LIMA JUNIOR.pdf: 4252506 bytes, checksum: 714cb7aa7e2dc62943c697bd35a222ed (MD5) / Made available in DSpace on 2015-03-13T13:00:53Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao JOSIAS de LIMA JUNIOR.pdf: 4252506 bytes, checksum: 714cb7aa7e2dc62943c697bd35a222ed (MD5) Previous issue date: 2013-05 / Recent years have witnessed the emergence of new communication techniques in Computer Science that use both wireless technologies and self-organizing features. Their combination eliminates the need for using pre-defined wired structures and prior configurations. In this work, we develop a simulated version, using the network simulator 3 (ns-3), of the Heterogeneous Technologies Routing (HTR) framework that is suitable for interconnecting devices in a heterogeneous ad hoc network, extending its supported heterogeneous technologies with the addition of WiMAX and LTE devices, proposes an extension to enable multipath routing over this framework and investigates the impact of tuning routing parameters on convergence interval and energy consumption. Although a large number of works exist that investigate the tuning of routing parameter settings, to the best of our knowledge, none of them investigate the impact of these on protocol convergence and energy consumption. Multipath HTR routing, the extension we propose, offers several benefits such as load balancing, fault tolerance, routing loop prevention, energy-conservation, low end-to-end delay, and congestion avoidance, among others. This work performs a comparative analysis of the proposed HTR extension, with the baseline HTR, and the widely used Optimized Link State Routing (OLSR) protocol. Moreover, we investigate the impacts of tuning the HELLO refresh interval and perform a comparative analysis of the tuned HTR with the OLSR protocol. Both evaluations are validated through the simulation of heterogeneous technologies such as WiMAX, 3GPP LTE and Wi-Fi. Results show that the multipath extension effectively improves the data delivery ratio, and reduces the end-to-end delay without major impact on network energy consumption. For the tuned HTR, results show that varying the HELLO refresh interval can improve the convergence of the protocol and reduce the energy consumption. / Recentemente, novas técnicas de comunicação surgiram que usam tecnologia sem fio e são capazes de se autoconfigurar. A combinação desses fatores elimina a necessidade de utilizar estruturas cabeadas e configurações pré-definidas. Neste trabalho, o autor desenvolve uma versão simulada, através do simulador de rede “network Simulator 3” (ns-3), do arcabouço “Heterogeneous Technologies Routing” (HTR), que se propõe à interconectar dispositivos em redes heterogêneas ad hoc, estendendo o seu suporte às tecnologias heterogêneas com a adição de dispositivos WiMAX e LTE, propõe uma extensão para fornecer um roteamento baseado em múltiplos caminhos (“Multipath”) e investiga o impacto de modificar os parâmetros de configuração do roteamento no tempo de convergência da rede e consumo de energia. Apesar de um grande número de obras existentes que investigam o impacto da mudança de parâmetros de configuração do roteamento, no meu conhecimento, nenhum deles investiga o impacto destes no tempo de convergência do protocolo e consumo de energia. O “Multipath HTR”, a extensão proposta, oferece vários benefícios como balanceamento de carga, tolerância a falhas, prevenção de “loops” de roteamento, conservação de energia, baixo atraso fim-a-fim, e evita o congestionamento, entre outros. Este trabalho faz uma análise comparativa da extensão ao HTR proposta, com a base do HTR, e o protocolo amplamente utilizado “Optimized Link State Routing” (OLSR). Além disso, o esse trabalho investiga o impacto de variar o intervalo de envio de mensagens de HELLO e realiza uma análise comparativa do HTR modificado (“Tuned HTR”) com o protocolo OLSR. As duas avaliações são realizadas através de simulação usando tecnologias heterogêneas como WiMAX, 3GPP LTE e Wi-Fi. Resultados mostram que a extensão de múltiplos caminhos proposta melhora a taxa de transmissão de dados, e reduz o atraso fim-a-fim sem maiores impactos no consumo de energia da rede. Para o “Tuned HTR”, resultados mostram que a variação do intervalo de envio de mensagens de HELLO pode melhorar a convergência do protocolo e reduz o consumo de energia.

Το πρόβλημα της κλιματικής αλλαγής αποτελεί έναν από τα κυριότερα σημεία έντονου ενδιαφέροντος για τις περισσότερες χώρες. Μάλιστα, τα επόμενα χρόνια αναμένεται να δοθεί μεγαλύτερη προσοχή στην ανάπτυξη πολιτικών που θα μειώνουν τις εκπομπές ρυπογόνων αέριων ρύπων. Η εξοικονόμηση ενέργειας, ως μέτρο πολιτικής, θα συνεχίσει να αποτελεί μια σημαντική στρατηγική ανάπτυξης για την οικονομία της χώρας μας, μια και συνδέεται σε σημαντικό βαθμό, με την κατανάλωση ενέργειας όπως και με την μείωση των εκπομπών αερίων ρύπων. Επιπλέον, συντονισμένες προσπάθειες τόσο από την Ευρωπαϊκή Ένωση όσο και από άλλους οργανισμούς (IEA, OECD) θέτουν σε βασικό άξονα προτεραιότητας την μείωση της κατανάλωσης ενέργειας, την χρησιμοποίηση εναλλακτικών μορφών και ανανεώσιμων πηγών και την μείωση των ρυπογόνων εκπομπών ιδιαίτερα στον βιομηχανικό κλάδο. Στα πλαίσια της παρούσας διατριβής αναλύονται θέματα που σχετίζονται με την υιοθέτηση τεχνολογιών εξοικονόμησης ενέργειας από Βιομηχανικές επιχειρήσεις. Κεντρικό στοιχείο αυτής της προσέγγισης είναι το “Παράδοξο της Ενεργειακής Αποδοτικότητας”. Τρία συγκεκριμένα θέματα εξετάζονται σε αυτή την κατεύθυνση. Πρώτον, η διερεύνηση των παραγόντων που οδηγούν στην εμφάνιση του “παραδόξου της ενεργειακής αποτελεσματικότητας” και συγκεκριμένα αν οι αποφάσεις των επιχειρήσεων για υιοθέτηση τέτοιων τεχνολογιών συνυπολογίζουν το στοιχείο της αποδοτικότητας των επενδεδυμένων κεφαλαίων. Δεύτερον, και με δεδομένο ότι στα αποτελέσματα του προηγούμενου σταδίου ανάλυσης αναδεικνύουν την σημαντικότητα του παράγοντα της πληροφορίας, αναπτύσσεται μια εκτενής προσέγγιση που αφορά τόσο το περιεχόμενο όσο και τον ρόλο του παράγοντα της πληροφορίας στην διαδικασία υιοθέτησης ΤΕΕ. Τρίτο, διερευνάται η επίδραση της υιοθέτησης των ΤΕΕ στην παραγωγική αποτελεσματικότητα και παραγωγικότητα των βιομηχανικών επιχειρήσεων. Για τις ανάγκες της ανάλυσης αυτών των θεμάτων αναπτύσσονται δύο επιμέρους μικροοικονομικά υποδείγματα και μια μέθοδος μέτρησης της παραγωγικότητας σε ετερογενής τεχνολογίες. Το πρώτο μικροοικονομικό υπόδειγμα διερευνά την διαδικασία λήψης επενδυτικών αποφάσεων σε ΤΕΕ υπό το πρίσμα της συσχέτισης της επενδυτικής επιλογής με την κερδοφορία, σε πλαίσιο μερικής παρατηρησιμότητας. Το δεύτερο μικροοικονομικό υπόδειγμα επανατοποθετεί την έννοια της πληροφορίας και διερευνά τους παράγοντες που προσδιορίζουν το επίπεδο πληροφόρησης της επιχείρησης για ΤΕΕ. Τέλος για την μέτρηση της επίδρασης των ΤΕΕ στην παραγωγική αποτελεσματικότητα και παραγωγικότητα αναπτύσσεται μια μέθοδος που λαμβάνει ρητά υπόψη της την τεχνολογική ετερογένεια. Η διερεύνηση των τριών αυτών ζητημάτων βασίζεται στην ανάλυση εμπειρικών δεδομένων που αφορούν επιχειρήσεις οι οποίες ενέταξαν στην παραγωγική τους διαδικασία τεχνολογίες εξοικονόμησης ενέργειας στην περίοδο 1990-2004. Οι επενδύσεις αυτές επιδοτήθηκαν κυρίως στα πλαίσια του Β’ και Γ’ Κοινοτικού Πλαισίου Στήριξης. Τα δεδομένα συλλέχθηκαν με την μέθοδο των προσωπικών συνεντεύξεων (ερωτηματολόγια). Συμπληρωματικά δεδομένα αντλήθηκαν από την βάση δεδομένων της ICAP. / The improvement for energy efficiency is generally viewed as an important option to reduce greenhouse gas emissions and environmental damage caused by other pollutants (e.g. NOX,SOX). Moreover, is clearly interwoven with the exploitation of new and innovative technologies through the production process and its consequent paradox, the so called “energy efficiency paradox”. This paradox has recently attracted the interest of researchers and organizations (IEA,OECD) in an attempt to bring to light the source of it, the causalities between the adoption of energy efficient technology (EET) and the behaviour of firms . Three research questions have been examined in the specific Phd Thesis. Our first main research question were examined by formulating and testing the following hypothesis: the decision of the firms to adopt or not EET, is correlated to their profitability. Our second research project develops in two stages. The first stage aims at examining the factors influencing retrieval of information concerning EETs by manufacturing firms, while at the second stage we distinguish between readily available and emerging energy efficiency technologies and examine the factors affecting information acquisition for each one of these two broad sets of technologies. Finally, in order to disentangle firm’s heterogeneity we developed a methodological framework to calculate total factor productivity and its components differences arising from EETs adoption. Our first research question examines the energy efficiency paradox demonstrated in Greek manufacturing firms through a partial observability approach. Maximum likelihood estimates that arise from an incidental truncation model reveal that the adoption of the energy saving technologies is indeed strongly correlated to the returns of assets that are required in order to undertake the corresponding investments. The source of the energy efficiency paradox lies within a wide range of factors. Policy schemes that aim to increase the adoption rate of energy saving technologies within the field of manufacturing are significantly affected by differences in the size of firms. Finally, mixed policies seem to be more effective than polices that are only capital subsidy or regulation oriented. Answering the second research question, we aim to redefine the notion of awareness regarding the adoption of EETs. In a second stage we explore the crucial factors that affect the information level of EET adopters, distinguishing between epidemic and emerging technologies information. Our empirical findings reveal that the main factor that exerts positive influence on the level of information acquired by the firms may be encompassed in a set of variables that reflect what may be called a “business culture” regarding the EET Finally, we examined the impact of EETs adoption to Greek manufacturing firms operating under heterogeneous technology sets and we measured the components of total factor productivity (TFP) and its components arising from scale and technological differences. In order to examine our research questions we formulate a unique database. Our database came to light from the necessity of the Greek government to conserve energy in manufacturing and to reduce dangerous emissions in order to meet the criteria of the Kyoto Protocol. An extensive questionnaire was addressed to the 298 firms across the country that adopt EETs that have been subsidized from (i) the Support Frameworks for Regional and Industrial Development, (ii) the Energy Operational Program (OPE), which was part of the second European Union Support Framework (1994-2000) and (iii) the Operational Program ‘Competitiveness’, which is part of the third European Union Support Framework (2000-2006). Finally, 161 of them agreed to be interviewed on the basis of the questionnaire. Face to face interviews took place in the first six months of 2004. Additional data derived from ICAP financial database.