The human society exerts its influence on the ecosystem through economic activities. While the robustness of an economy manifests through its industrial structure, human impact on nature is well represented by an economy's energy consumption patterns. Therefore, evaluating the industrial structure and unraveling its interconnection with energy consumption is crucial for achieving sustainable development. In this dissertation, I address the topic from several perspectives. First, I start with an exploratory analysis on the industrial structure itself, developing an easy measure, revealed comparative dependence (RCD), to compare regional dependence on sectors. Building on the RCD measure, I indirectly evaluate the economic resilience of U.S. states by quantifying their economic diversity. Second, I bring the measure for industrial structure into context with energy consumption patterns. RCD is used to characterize sector interactions, which are then used to explain the historical trend of regional energy consumption. I find that while the expansion of low energy intensity sectors does reduce energy use, these sectors' level of interaction with other sectors also plays a key role in determining energy use. As a third step, I investigate how regional structure affects an economy's response towards energy efficiency improvements, i.e., the economy-wide rebound effect. My regional computable general equilibrium (CGE) model proves that production-side energy efficiency improvement induces moderate rebound effects, while feeding back into the industrial structure by changing sectoral production scale in different directions. I also identify sectors being able to trigger different levels of energy saving and energy rebound, and explore the mechanism for their impact propagation throughout the industrial structure. This study establishes the linkage between regional industrial structure and energy consumption from different perspectives. From the scientific perspective, it improves the fundamental understanding of how industrial structure and energy consumption are intricately connected to each other. From the policy perspective, it informs policy makers of the importance of considering sector interaction when designing energy policies, as well as the effectiveness of efficiency measures in achieving energy conservation.

M. Tech. Industrial Engineering. / Discusses the main objectives of this research are to; analyse the current state of press brakes technology ; develop a press brake concept using the Screw Jack System applying DFM (designing for manufacturability) principles and to fabricate a mini prototype Screw Jack Press Brake.

A family of top-down statistical models describing energy consumption in the mining, milling, and refining of uranium are formulated. The purpose of the models is to estimate the energy-to-grade dependence for uranium extraction, while defining a minimum grade that can be feasibly mined and produced. The results serve as a basis for understanding the factors governing energy consumption in the production of U3O8. The models are applied to a considerably larger data set of operating mines than in any previous effort. In addition, the validity of the modeling approach is established by modeling energy for two other commodities, gold and copper, thereby showing it can be applied to other metals. Statistical measures of explanatory power show that the models the energy-to-grade relationship is well-described for both uranium and gold. For copper, there was insufficient data over a broad range of ore grades to obtain a model that passed statistical confidence measures. The results show that mining of lower-grade deposits of uranium is likely to be less energy-intensive than previous investigators concluded. It is shown that the uncertainty in the results is dominated by the contribution of the grade-independent component of energy consumption. / text

published_or_final_version / abstract / toc / Botany / Doctoral / Doctor of Philosophy

The thesis examines the consumption of electricity and gasoline in the Ivory Coast, Ghana and Senegal. Its main objectives are (1) to investigate the determinants of the demand for gasoline and the demand for electricity by households and firms, (2) to forecast the level of electricity and gasoline consumption for the years 1980 to 1985, and (3) to recommend measures to curb the rate of increase in the demand for energy and to reduce the dependence upon imported oil. The choice of the models used in the estimation of the demand for gasoline and the demand for electricity by households and industries were greatly influenced by the fact that energy consumption is associated with that of other complementary durable goods. The models of gasoline demand fitted to annual data for the Ivory Coast were the stock-adjustment model and the Koyck model. The empirical results of the residential demand for electricity are based on the Koyck model, the flow-adjustment model and the new demand model. As to the estimates of the industrial demand for electricity they were obtained with the following models: The Koyck model, the new demand model, a model based on an overtime profit maximization by a firm. The results based on the gasoline demand equations indicate that income is a major determinant of gasoline consumption in Senegal, while in the Ivory Coast, habit formation and or stock adjustment are the determinant factors. As far as price is concerned, it has consistently negative elasticities both across countries and specifications, but is not significant. For the residential demand for electricity, the results are much more encouraging. All of the countries show that price and the social and demographic factors and per-capita income are major predictors of residential electricity consumption. Their relative importance differ, however, both across countries and specification. The lagged dependent variable is significant with the new demand for electricity for Senegal and Ghana, and with the Koyck model for the Ivory Coast. Finally, the results for the industrial demand for electricity indicate that price, capital stock, and wage have an influence on the level of electricity consumed in the Ivory Coast, Senegal and Ghana. In addition to the variables mentioned above, output is also an important predictor of industrial electricity consumption in the Ivory Coast. On the basis of these findings, we recommended the following measures: (1) to increase the price of electricity and gasoline over a reasonably long period so that the relative price of different fuels reflect the change in relative cost of alternative fuel production; (2) to adopt a development strategy based on the implementation of export-oriented industries and the progressive removal of the trade barrier behind which the import-substitution industries have been hiding; and, (3) to reconsider the non-commercial fuel (wood, charcoal) as an alternative source of energy.

No description available.

Στην παρούσα διδακτορική διατριβή ασχολούμαστε με ζητήματα ελαχιστοποίησης της κατανάλωσης ενέργειας που ανακύπτουν σε ασύρματα δίκτυα. Εξετάζουμε τόσο την περίπτωση ασυρμάτων δικτύων τύπου ad hoc όσο και την περίπτωση όπου υπάρχει ένα σταθερό ενσύρματο δίκτυο το οποίο συνδέει τους σταθμούς εκπομπής, οι οποίοι χρησιμοποιούν ασύρματα μέσα προκειμένου να μεταδώσουν μηνύματα στους χρήστες. Στην πρώτη κατηγορία, μελετούμε τόσο περιπτώσεις όπου η συνάρτηση κόστους στις ακμές είναι συμμετρική, όσο και περιπτώσεις όπου δεν ισχύει αυτή η υπόθεση. Εξετάζουμε επιπλέον προβλήματα που προκύπτουν όταν θεωρούμε ότι οι σταθμοί βρίσκονται σε κάποιον Ευκλείδειο χώρο και η απόσταση εξαρτάται από την Ευκλείδεια απόσταση. Παρουσιάζουμε αποτελέσματα υπολογιστικής δυσκολίας για την εύρεση τόσο της βέλτιστης λύσης όσο και μιας καλής προσεγγιστικής λύσης. Από την άλλη πλευρά, αποδεικνύουμε άνω φράγματα στον λόγο προσέγγισης διάφορων πολυωνυμικών αλγορίθμων. Στην περίπτωση που θεωρούμε πως οι σταθμοί μετάδοσης είναι συνδεδεμένοι με ένα ενσύρματο δίκτυο, έχουμε το πρόβλημα της συσταδοποίησης. Παρουσιάζουμε έναν βέλτιστο πολυωνυμικό αλγόριθμο για την περίπτωση όπου τα σημεία είναι συνευθειακά, ενώ αποδεικνύουμε αποτελέσματα υπολογιστικής δυσκολίας για την περίπτωση των δύο ή περισσοτέρων διαστάσεων. Τέλος, παρουσιάζουμε έναν προσεγγιστικό αλγόριθμο του οποίου ο λόγος προσέγγισης μπορεί να πλησιάσει αυθαίρετα κόντα το 1, με άλλα λόγια παρουσιάζουμε ένα προσεγγιστικό σχήμα πολυωνυμικού χρόνου. / In this dissertation we focus on issues related to energy consumption in wireless networks. We examine both ad hoc wireless networks, where we assume that there is no wired infrastructure, and networks where antennas are wired through a traditional, wired backbone network but they transmit messages to the users using wireless means. In the first case, we consider networks where the distance function can be symmetric or asymmetric; asymmetric edge cost functions can be used to model medium abnormalities or batteries with different energy levels. We prove results concerning the NP-hardness of computing the optimal solution or in some cases even an approximate solution, and also present upper bounds on the approximation ratio of several polynomial time algorithms. In the case where the antennas are connected through a wired backbone network, we consider a clustering problem. We present an optimal polynomial time algorithm for the special case when points are located on a line. We also present NP-hardness results concerning special cases of the problem in the case of 2 or more dimensions. Finally, we conclude with a polynomial time approximation scheme (PTAS).

Because of the needs for producing highly reliable products and reducing product development time, Accelerated Life Testing (ALT) has been widely used in new product development as an alternative to traditional testing methods. The basic idea of ALT is to expose a limited number of test units of a product to harsher-than-normal operating conditions to expedite failures. Based on the failure time data collected in a short time period, an ALT model incorporating the underlying failure time distribution and life-stress relationship can be developed to predict the product reliability under the normal operating condition. However, ALT experiments often consume significant amount of energy due to the harsher-than-normal operating conditions created and controlled by the test equipment used in the experiments. This challenge may obstruct successful implementations of ALT in practice. In this dissertation, a new ALT design methodology is developed to improve the reliability estimation precision and the efficiency of energy utilization in ALT. This methodology involves two types of ALT design procedures - the sequential optimization approach and the simultaneous optimization alternative with a fully integrated double-loop design architecture. Using the sequential optimum ALT design procedure, the statistical estimation precision of the ALT experiment will be improved first followed by energy minimization through the optimum design of controller for the test equipment. On the other hand, we can optimize the statistical estimation precision and energy consumption of an ALT plan simultaneously by solving a multi-objective optimization problem using a controlled elitist genetic algorithm. When implementing either of the methods, the resulting statistically and energy efficient ALT plan depends not only on the reliability of the product to be evaluated but also on the physical characteristics of the test equipment and its controller. Particularly, the statistical efficiency of each candidate ALT plan needs to be evaluated and the corresponding controller capable of providing the required stress loadings must be designed and simulated in order to evaluate the total energy consumption of the ALT plan. Moreover, the realistic physical constraints and tracking performance of the test equipment are also addressed in the proposed methods for improving the accuracy of test environment. In this dissertation, mathematical formulations, computational algorithms and simulation tools are provided to handle such complex experimental design problems. To the best of our knowledge, this is the first methodological investigation on experimental design of statistically precise and energy efficient ALT. The new experimental design methodology is different from most of the previous work on planning ALT in that (1) the energy consumption of an ALT experiment, depending on both the designed stress loadings and controllers, cannot be expressed as a simple function of the related decision variables; (2) the associated optimum experimental design procedure involves tuning the parameters of the controller and evaluating the objective function via computer experiment (simulation). Our numerical examples demonstrate the effectiveness of the proposed methodology in improving the reliability estimation precision while minimizing the total energy consumption in ALT. The robustness of the sequential optimization method is also verified through sensitivity analysis.

Šiuolaikinės technologis tobulėja labai sparčiai – itin greiti dedikuoti serveriai, didelio pralaidumo interneto kanalai, leidžia vis daugiau taikomųjų programų perkelti į virtualią erdvę, vadinamą „Debesų kompiuterija“. Šioje erdvėje vykstantys procesai užtikrina, kad visi viešinami kompiuteriniai resursai, pvz., programinė ir techninė įranga bei interneto srautas būtų optimaliai paskirstytas. Tai suteikia palankias sąlygas atsirasti naujoms paslaugoms: daugialypės informacijos transliavimas, dokumentų redagavimas internete ir pan. Tokio tipo paslaugos yra paremtos „plono kliento“ architektūra, kuri ypač svarbi mobiliesiems įrenginiams. Pagrindinis šios architektūros privalumas – taikomosios programos, kurioms reikia daug skaičiavimo išteklių, gali būti vykdomos serveriuose, o rezultatai pateikiami mobiliųjų įrenginių ekranuose. Faktas, jog programos nėra vykdomos mobiliajame įrenginyje, sumažina tikimybę, jog svarbi informacija bus užkrėsta virusų, kirmėlių. Tarp daugelio egzistuojančių mobiliųjų įrenginių problemų, noriu išskirti dvi: energijos sąnaudos ir informacijos apsauga. Pirmoji problema egzistuoja dėl neadekvataus progreso tarp kompiuterinių resursų ir baterijos energijos talpos (pvz., procesoriaus sparta per kelis metus padidėja keletą kartų, tačiau baterijos energijos talpa padvigubinama tik kartą į dekadą). Antroji problema yra artymai susijusi su pirmąją. Šiandien žmonės nori dirbti įvairiose vietose, tad atsiranda grėsmė, jog mobilus įrenginys, įskaitant... [toliau žr. visą tekstą] / Nowadays technologies are being improved rapidly – extremely fast dedicated servers, high internet and network throughput, enables more and more applications to be moved to a virtual space, which is called ‘Cloud computing’. Cloud computing is responsible that all shared computer resources, like Software, Hardware and Network would be allocated for services in optimal way. This feature enables to appear new services, like media streaming, documents editing online etc. This kind of services are based on ‘Thin client’ architecture, which is especially important for mobile devices. Main feature of this architecture is that applications which require many computations, now can be executed in dedicated servers and results can be displayed in mobile device screen. Fact, that aplication is not executed in mobile device environment decreases probability that important information will be infected by viruses, worms etc. However, between many existing problems with mobile devices there are two major which should be stated in the first place: energy consumption and information security. The first issue is due to inadequate progress of computational resources and battery energy power (e.g., CPU speed, memory capacity is being increased several times within a few years, while battery power doubles only in a decade). The second issue is closely related with the first one. Today people want to work anywhere, so there is abillity that mobile devices including important information could... [to full text]

The purpose of this thesis is to assess and compare the energy consumption and carbon footprints of two, online and offline, major movie rental services in Canada. The thesis is divided into two parts that represent two papers that are being published. The comprehensive literature survey provides the state-of-the-art in E-Commerce carbon footprinting with a new categorization framework. The model development and application compares the energy consumption and carbon footprints of the two business models via a systems approach and the Economic Input Output Life Cycle Assessment (EIO-LCA) model and evaluates environmental performances. The portions of the logistics chains that were different in the two business models were analyzed and processes that were common were excluded. Regarding findings, the analyses conclude that the online movie rental service has lower carbon footprint than the offline one. We suggest practical implications for policy makers, government, businesses, and customers in movie rental industry. / This thesis contains two papers, recently presented at international conferences and accepted for publication in recognized journals.