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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Extensions et nouvelles approches en extraction des connaissances à partir des données réduction unidimensionnelle et bidimensionnelle d'un tableau numérique, arbres de décision et introduction de coûts en apprentissage, sélection de variables /

Erray, Walid. Zighed, Djamel Abdelkader January 2006 (has links)
Thèse doctorat : Informatique : Lyon 2 : 2006. / Titre provenant de l'écran-titre. Bibliogr.
2

Apprentissage non supervisé et extraction de connaissances à partir de données

Jouve, Pierre-Emmanuel Nicoloyannis, Nicolas January 2003 (has links)
Reproduction de : Thèse de doctorat : Informatique : Lyon 2 : 2003. / Titre provenant de l'écran-titre. Bibliogr.
3

Contribution méthodologique à la fouille de données complexes

Clech, Jérémie Zighed, Djamel Abdelkader January 2004 (has links)
Reproduction de : Thèse de doctorat : Informatique : Lyon 2 : 2004. / Titre provenant de l'écran-titre. Bibliogr.
4

Krise Shell - Bewertung vom Rohstoffvorkommen Die Rechnungslegung von Aktivitäten der Explorationsphase bei Rohstoffproduzenten /

Wagner, Sascha Benjamin. January 2005 (has links) (PDF)
Bachelor-Arbeit Univ. St. Gallen, 2005.
5

Forecasting oil and gas reserves and production in the UK North Sea : a Monte Carlo approach

Hatami, Hossein January 1996 (has links)
This thesis examines the results of the future exploration drilling activities expected to be committed between 1995-2014 in the mature areas of the UK North Sea. The study employs Monte Carlo simulation techniques to quantify the risk of exploration ventures by estimating the expected value of the exploration decisions in a mature hydrocarbon province where both the exploration success and the size of the discovered fields are shown to be diminishing with advancing exploration. The study explicitly takes into account the risks which are associated with both geological and economic uncertainties. The prime objective is to model and forecast the significant quantities of oil, condensate, and gas to be discovered given the specified levels of committed exploratory effort. Due to the presence of different geological and prospectivity characteristics, the whole North Sea province is divided into three basins namely the Southern, Central and Northern basins each of which has been treated and studied separately. The commercial merits of the future discoveries for potential development purposes have been determined through the application of different parameters for future oil and gas prices, various costs of field exploration and development, etc. The impact of the fiscal regime on the commercial viability of the future discoveries has also been explicitly examined. After identifying the future discoveries with commercial significance in the North Sea, their resulting production, costs, revenues, tax bill, and the net present values are presented in detail. To create a wider picture for the new field discoveries and their eventual contribution to the overall production in the North Sea, the future exploration and production activities have been examined under three different scenarios each reflecting varying geological and economic circumstances.
6

Réalité augmentée haptique : théorie et applications / Haptics augmented reality : theory and applications

Bayart, Benjamin 07 December 2007 (has links)
Dans cette thèse, nous introduisons le concept de Réalité Augmentée Haptique (RAH) en définissant une taxonomie à deux axes. Le premier dénommé Haptique Augmentée (HA) représente l’ensemble des applications qui modifient/augmentent une donnée haptique existante. Le second axe, appelé Augmentation Haptique (AH), considère les applications qui utilisent la modalité haptique pour fournir une information supplémentaire à l’utilisateur. Par la suite, nous illustrons ces concepts sous forme d’une application de télé-diagnostic, permettant l’exploration d’un objet mixte, composé de parties réelles et virtuelles, ou la comparaison entre un objet réel et un virtuel ; d’un nouvel algorithme pour l’enseignement d’un chemin par guidage haptique, tout en évitant les problèmes de passivité et de dépendance de l’apprenti ; et de l’emploi de ces deux notions dans une application de peinture virtuelle sur un quelconque objet réel (avec croisement d’augmentations visio-haptique), le tout enrichi d’un processus visuel de Réalité Diminuée. / This thesis introduces the concept of Haptics Augmented Reality (HAR) defining a taxonomy of two concepts. The first called Enhanced Haptics (EH) consists in applications that enhance/modify/… an existing haptic data. The second concept, named Haptic Enhancing (HE), considers applications using the haptic channel to provide additional information to the user. Thereafter, these concepts are illustrated as a tele-diagnosis application, enabling the exploration of a mixed object, composed of real and virtual parts, or the comparison between a real object and a virtual one; as a new algorithm of haptic guidance dedicated to path teaching scenarios, avoiding the problems of passivity and dependence of he apprentice; and the use of these two concepts within a application of virtual painting onto any real object, enriched with a visual Diminished Reality process.
7

GEOCHEMICAL INDICATORS OF BURIED SULPHIDE MINERALISATION UNDER SEDIMENTARY COVER NEAR TALBOT LAKE, MANITOBA

van Geffen, Pim Wilhelmus Gerardus 16 May 2011 (has links)
The Paleoproterozoic Talbot volcanogenic massive sulphide (VMS) Cu-Zn occurrence is located near Talbot Lake, Manitoba, about 80 km south of Snow Lake. The mineralised system is unconformably overlain by more than 100 m of Paleozoic dolomite sequences and Quaternary glacial till. The clay fraction of the till contains pronounced anomalies of Zn, Cu, Ag, Pb, Au, Mn, Hg, Cd, Co, Bi and Se, which is ascribed to the formation of clay-humic complexes that have carbon-isotopic compositions of δ13C < -20‰. A VMS origin of the near-surface anomaly is confirmed by distinctly low 206Pb/204Pb ratios, compared to a more radiogenic till signature. The overall low 206Pb/204Pb ratios in the organic surface media black spruce bark, moss and humus also indicate input from a magmatic sulphide source, but likely reflect windblown material from the Flin Flon smelter stack at 160 km to the northwest. Black spruce tree rings that pre-date industrial sources of atmospheric metal input are used to measure historical element distributions because they record the local geochemistry at the time of heartwood growth and their root systems tap into large volumes of soil. At the Talbot prospect, the presence of secondary Zn from the till in black spruce tree cores is reflected in the Zn/Ca ratio, which eliminates the effect of dolomite-derived Zn. The process of element migration from buried mineralisation to the surface is complex and includes oxidation of sulphides, mobilisation and complexation of metal ions, physical upward transport, and deposition of indicator elements near the surface in accessible sampling media. To account for a significant influx of indicator elements into the relatively recently deposited till blanket, post-glacial groundwater upwelling is proposed to act as a major mechanism driving upward element migration. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2011-05-14 04:38:36.886
8

Heuristics for strategic ambidexterity: balancing exploration and exploitation over time in varying environments

Laplume, Andre 01 September 2010 (has links)
Drawing on studies of strategic dynamics and organizational change, this thesis proposes four approaches to balancing exploration and exploitation over time: Specialist, Cyclical, Irregular, and Regular. Various approaches to ambidexterity may be more effective under different environment conditions, and performance may vary along with: 1) varying types of rule change environments, 2) varying levels of competitive intensity among firms, 3) reactive versus proactive timing heuristics, and 4) varying levels of product diversification. Several hypotheses are developed and confirmed using qualitative field research and agent-based modeling. Results indicated that strategic leaders should balance their exploration and exploitation with Regular ambidexterity as their environments become dominated by competence enhancing innovation. Conversely, firms should temporally shift their balance of exploration and exploitation when competence-destroying changes dominate. In a balanced environment, Irregular ambidexterity performs best. These finding are especially relevant in highly competitive contexts. Also, proactive switching increases performance more than reactive switching, whereas diversification reduces the performance of sequential heuristics.
9

Heuristics for strategic ambidexterity: balancing exploration and exploitation over time in varying environments

Laplume, Andre 01 September 2010 (has links)
Drawing on studies of strategic dynamics and organizational change, this thesis proposes four approaches to balancing exploration and exploitation over time: Specialist, Cyclical, Irregular, and Regular. Various approaches to ambidexterity may be more effective under different environment conditions, and performance may vary along with: 1) varying types of rule change environments, 2) varying levels of competitive intensity among firms, 3) reactive versus proactive timing heuristics, and 4) varying levels of product diversification. Several hypotheses are developed and confirmed using qualitative field research and agent-based modeling. Results indicated that strategic leaders should balance their exploration and exploitation with Regular ambidexterity as their environments become dominated by competence enhancing innovation. Conversely, firms should temporally shift their balance of exploration and exploitation when competence-destroying changes dominate. In a balanced environment, Irregular ambidexterity performs best. These finding are especially relevant in highly competitive contexts. Also, proactive switching increases performance more than reactive switching, whereas diversification reduces the performance of sequential heuristics.
10

Some techniques for the enhancement of electromagnetic data for mineral exploration.

Sykes, Michael P. January 2000 (has links)
The usefulness of electromagnetic (EM) methods for mineral exploration is severely restricted by the presence of a conductive overburden. Approximately 80% of the Australian continent is covered by regolith that contains some of the most conductive clays on Earth. As a result, frequency-domain methods are only effective for near surface investigations and time-domain methods, that are capable of deeper exploration, require the measurement of very small, late-time signals. Both methods suffer from the fact that the currents in the conductive Earth layers contribute a large portion of the total measured signal that may mask the signal from a conductive target. In the search for non-layered structures, this form of geological noise is the greatest impediment to the success of EM surveys in conductive terrains. Over the years a range of data acquisition and processing techniques have been used in an effort to enhance the response of the non-layered target and thereby increase the likelihood of its detection.The combined use of a variety of survey configurations to assist exploration and interpretation is not new and is practiced regularly. The active nature of EM exploration means that the measured response is determined to a large degree by the way in which the Earth is energised. Geological structures produce different responses to different stimuli. In this work, two new methods of data combination are used to transform the measured data into a residual quantity that enhances the signature of non-layered geological structures. Based on the concept of data redundancy and tested using the results of numerical modelling, the new combinations greatly increase the signal to noise ratio for targets located in a conductive environment by reducing the layered Earth contribution. The data combinations have application to frequency-domain and time-domain EM surveys and simple ++ / interpretive rules can be applied to the residuals to extract geological parameters useful in exploration. The new methods make use of inductive loop sources and can therefore also be applied to airborne surveys.Airborne surveys present special difficulties due to the data acquisition procedures commonly used. Flight-line related artefacts such as herringbones detract from the appearance of maps and make boundary definition more difficult. A new procedure, based on the Radon transform, is used to remove herringbones from airborne EM maps and locate the conductive boundaries correctly, making interpretation more reliable and easier. In addition, selective filtering of the Radon transform data enables the enhancement or attenuation of specific linear features shown in the map to emphasise features of interest. Comparison of the Radon transform procedures with the more conventional Fourier transform methods shaves the Radon transform processing to be more versatile and less prone to distortion of the features in a map.The procedures developed in this work are applied to field data with good results.

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