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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.
361

Demand side management on an intricate multi-shaft pumping system from a single point of control / Shane Thein

Thein, Shane January 2007 (has links)
Thesis (M.Ing. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.
362

Collaboration in multi-agency teams : a case study in child protection / by Motlapele Lucy Tserema

Tserema, Motlapele Lucy January 2008 (has links)
Thesis (M.A. (Social Work))--North-West University, Potchefstroom Campus, 2008.
363

A cognitive approach to multi-verb constructions in Mandarin Chinese

Yin, Hui 11 1900 (has links)
This dissertation addresses different kinds of Mandarin multi-verb constructions (MVCs), seeking to solve a long-standing problem in Chinese linguistics: namely, how to account for a plethora of constructions, including a subset called serial verb constructions. In most previous studies, only a limited number of MVCs have been examined by any one researcher. By contrast, this dissertation aims to provide a unified account of all types of Mandarin MVCs. I argue such a goal can be achieved through a usage-based cognitive approach. By proposing that MVCs display varying degrees of event integration, my analysis can differentiate meaningfully among distinct kinds of MVCs. Based on the form-meaning pairing criterion, I argue that MVCs of different types can be localized along portions of a continuum of event integration. This study mines the Lancaster Corpus of Mandarin Chinese for MVCs. The corpus results show there is lexical restrictedness as measured by verb type/token ratios in certain MVCs. The continuum of type/token ratios is argued to correlate with the continuum of event integration of MVCs, with lower ratios correlating with higher degrees of event integration and with higher ratios correlating with lower degrees of event integration. The corpus data indicate there is a strong interaction between lexical items and construction types. Certain verbs are easily attracted to a particular construction or even a particular verb position. Also, the corpus results reflect an asymmetry in MVCs in that verbs in one position may be more restricted. The position-specific patterns of type/token frequency largely reveal the event structures underlying particular MVCs. Generally, the verb position having a higher type/token ratio represents a core phase. The corpus results show the mutual attraction of verbs and constructions, the strong tendency to use MVCs for encoding unitary albeit complex events, and the link between lexical restrictedness and event integration as evidenced by the large variety of types of MVCs in Mandarin. The findings support a usage-based model where constructions are understood to be conventionalized units, and fixed idiomatic expressions are considered to be as important to the expressive inventory of the language as are open or fully productive syntactic structures.
364

Pixel-level Image Fusion Algorithms for Multi-camera Imaging System

Zheng, Sicong 01 December 2010 (has links)
This thesis work is motivated by the potential and promise of image fusion technologies in the multi sensor image fusion system and applications. With specific focus on pixel level image fusion, the process after the image registration is processed, we develop graphic user interface for multi-sensor image fusion software using Microsoft visual studio and Microsoft Foundation Class library. In this thesis, we proposed and presented some image fusion algorithms with low computational cost, based upon spatial mixture analysis. The segment weighted average image fusion combines several low spatial resolution data source from different sensors to create high resolution and large size of fused image. This research includes developing a segment-based step, based upon stepwise divide and combine process. In the second stage of the process, the linear interpolation optimization is used to sharpen the image resolution. Implementation of these image fusion algorithms are completed based on the graphic user interface we developed. Multiple sensor image fusion is easily accommodated by the algorithm, and the results are demonstrated at multiple scales. By using quantitative estimation such as mutual information, we obtain the experiment quantifiable results. We also use the image morphing technique to generate fused image sequence, to simulate the results of image fusion. While deploying our pixel level image fusion algorithm approaches, we observe several challenges from the popular image fusion methods. While high computational cost and complex processing steps of image fusion algorithms provide accurate fused results, they also makes it hard to become deployed in system and applications that require real-time feedback, high flexibility and low computation ability
365

Multi-area power system state estimation utilizing boundary measurements and phasor measurement units ( PMUs)

Freeman, Matthew A 30 October 2006 (has links)
The objective of this thesis is to prove the validity of a multi-area state estimator and investigate the advantages it provides over a serial state estimator. This is done utilizing the IEEE 118 Bus Test System as a sample system. This thesis investigates the benefits that stem from utilizing a multi-area state estimator instead of a serial state estimator. These benefits are largely in the form of increased accuracy and decreased processing time. First, the theory behind power system state estimation is explained for a simple serial estimator. Then the thesis shows how conventional measurements and newer, more accurate PMU measurements work within the framework of weighted least squares estimation. Next, the multi-area state estimator is examined closely and the additional measurements provided by PMUs are used to increase accuracy and computational efficiency. Finally, the multi-area state estimator is tested for accuracy, its ability to detect bad data, and computation time.
366

Calibration and data reduction algorithms for non-conventional multi-hole pressure probes

Ramakrishnan, Vijay 30 September 2004 (has links)
This thesis presents the development of calibration and data-reduction algorithms for non-conventional multi-hole pressure probes. The algorithms that have been developed for conventional 5- and 7-hole probes are not optimal for probes with port arrangements (on the probe tip) that are non-conventional. Conventional algorithms utilize the axisymmetry of the port distribution pattern to define the non-dimensional pressure coefficients. These coefficients are typically defined specifically for these patterns, but fail to correctly represent different patterns of port arrangements, such as patterns without axisymmetry or regularity. The algorithms introduced herein can handle any pattern of port arrangement, from axisymmetric and regular to random. Moreover, they eliminate the need to separate the measurement domain of a probe to "low-angle" and "high-angle" regimes, typical in conventional 5- and 7-hole-probe algorithms that require two different sets of pressure coefficient definitions and procedures. Additionally, the algorithms have been formulated such that they facilitate redundancy implementations, especially in applications where such redundancy is important, such as air-data systems. The developed algorithms are first applied to a non-conventional probe, a nearly omni-directional 18-hole probe, and demonstrate very high flow measurement accuracy. Subsequently, the algorithms were applied to a new 12-hole, nearly omni-directional, flow velocity measurement probe capable of measuring reversed flows. The new 12-hole design offers several advantages over a previously developed, 18-hole, nearly omni-directional probe. The probe is optimized in the sense that, regardless of the flow direction, it allows calculation of the 4 unknown flow quantities, i.e. the two flow angles, the velocity magnitude and the static pressure, with the minimum necessary number of holes/ports on the probe tip. This probe also has a non-conventional arrangement of its pressure ports and therefore the new calibration and data-reduction algorithms can be effectively employed. With theoretically generated pressure data for the 12-hole probe, the coefficient definitions are analyzed and found to be well-behaved.
367

Sélection Séquentielle en Environnement Aléatoire Appliquée à l'Apprentissage Supervisé

Caelen, Olivier 25 September 2009 (has links)
Cette thèse se penche sur les problèmes de décisions devant être prises de manière séquentielle au sein d'un environnement aléatoire. Lors de chaque étape d'un tel problème décisionnel, une alternative doit être sélectionnée parmi un ensemble d'alternatives. Chaque alternative possède un gain moyen qui lui est propre et lorsque l'une d'elles est sélectionnée, celle-ci engendre un gain aléatoire. La sélection opérée peut suivre deux types d'objectifs. Dans un premier cas, les tests viseront à maximiser la somme des gains collectés. Un juste compromis doit alors être trouvé entre l'exploitation et l'exploration. Ce problème est couramment dénommé dans la littérature scientifique "multi-armed bandit problem". Dans un second cas, un nombre de sélections maximal est imposé et l'objectif consistera à répartir ces sélections de façon à augmenter les chances de trouver l'alternative présentant le gain moyen le plus élevé. Ce deuxième problème est couramment repris dans la littérature scientifique sous l'appellation "selecting the best". La sélection de type gloutonne joue un rôle important dans la résolution de ces problèmes de décision et opère en choisissant l'alternative qui s'est jusqu'ici montrée optimale. Or, la nature généralement aléatoire de l'environnement rend incertains les résultats d'une telle sélection. Dans cette thèse, nous introduisons une nouvelle quantité, appelée le "gain espéré d'une action gloutonne". Sur base de quelques propriétés de cette quantité, de nouveaux algorithmes permettant de résoudre les deux problèmes décisionnels précités seront proposés. Une attention particulière sera ici prêtée à l'application des techniques présentées au domaine de la sélection de modèles en l'apprentissage artificiel supervisé. La collaboration avec le service d'anesthésie de l'Hôpital Erasme nous a permis d'appliquer les algorithmes proposés à des données réelles, provenant du milieu médical. Nous avons également développé un système d'aide à la décision dont un prototype a déjà été testé en conditions réelles sur un échantillon restreint de patients.
368

Quantum chemical calculations of non-linear optical absorption

Cronstrand, Peter January 2004 (has links)
This thesis represents a quantum chemical treatise ofvarious types of interactions between radiation and molecularsystems, with special emphasis on the nonlinear opticalprocesses of Multi-Photon Absorption and Excited StateAbsorption. Excitation energies, transition dipole moments,two-photon and three-photon tensor elements have beencalculated from different approaches; density functional theoryandab-initiotheory, employing different orders ofcorrelation treatment with the purpose to provide accuratevalues as well as evaluate the quality of the lower ordermethods. A combined study of the Multi-Photon Absorption andExcited State Absorption processes is motivated partly becausethey both contribute to the total optical response of a systemsubjected to intense radiation, but also because of theirconnection through so-called sum-over-states expressions. Thelatter feature is exploited in a generalized few-states model,which incorporates the polarization of the light and thedirections of the transition dipole moments constructing anexcitation channel, which thereby enables a more comprehensivecomparison of the attained transition dipole moments withexperimental data. Moreover, by decomposing a complex nonlinearresponse process such as Two-Photon Absorption into moreintuitive quantities, generalized few-states models may alsoenable a more elaborate interpretation of computed orexperimental results from which guidelines can be extracted inorder to control or optimize the property of interest. Ageneral conclusion originating from these models is that thetransition dipole moments in an excitation channel should bealigned in order to maximize the Two-Photon Absorptionprobability. The computational framework employed is responsetheory which through the response functions (linear, quadratic,cubic) offers alternative routes for evaluating the propertiesin focus; either directly and untruncated through the singleresidue of the quadratic or cubic response func- tions orthrough various schemes of truncated sum-over-statesexpressions where the key ingredients, transition dipolemoments, can be identified from the single residue of thelinear response function and double residue of the quadraticresponse function. The range of systems treated in the thesisstretches from diatomics, such as carbon monoxide and lithiumhydride, via small to large fundamental organic molecules, suchas formaldehyde, tetrazine and the trans-polyenes, to largechro- mophores, such astrans-stilbene, cumulenes, dithienothiophene,paracyclophane and organo-metallic systems, such as theplatinum(II)ethynyl compounds. / QC 20120320
369

A Prescriptive Approach to Eliciting Decision Information

Riabacke, Mona January 2012 (has links)
The amount of information involved in many decision making situations has increased dramatically in recent years and support of some kind is often needed. Consequently, fields like Business Intelligence (BI) and Decision Support Systems (DSS) have advanced. Decision analysis applications belong to the latter category and aim to support decision making activities in businesses and organizations, and provide more clearly structured decision material to use as a basis for decisions. In spite of a belief in their potential, their employment is still limited in practice, which could partly be attributed to the fact that they are incomplete to support decision processes sufficiently in real settings. At present, e.g., the specification and execution of the elicitation of input data is often left to the discretion of the user. Yet, this involves quite a few problematic elements and is of importance for the quality of the process as a whole. This thesis focuses on more practically useful elicitation of information in decision analysis applications than what is offered today. A process model emphasizing the importance of structured elicitation of adequate input data throughout decision processes is also suggested. In order to further define the problematic aspects of elicitation, three empirical studies were conducted. The problems with eliciting precise decision data suggests that using imprecise values within elicitation is a more realistic and useful approach to strive for. Based on theory and the findings of the studies, a weight elicitation method for imprecise statements and noisy input was formalized into the Cardinal Rank Ordering of Criteria (CROC) method. This method is both compatible with an adapted prescriptive decision making model, focused on a more structured elicitation component, as well as algorithms for dealing with such data. The CROC method was employed and validated in two real-life cases, which is not so common within decision analysis research. / Mängden information i många beslutssituationer har ökat markant under senare år och det finns ofta behov av någon form av stöd. Följaktligen har områden som Business Intelligence (BI) och Beslutsstödssystem (BSS) avancerat. Beslutsanalysverktyg tillhör den senare kategorin och syftar till att fungera som stöd vid beslutsfattande inom företag och organisationer och tillhandahålla mer strukturerat underlag för beslut. Trots en tro på deras potential, så är deras användande begränsat i praktiken, vilket delvis kan tillskrivas det faktum att de är inkompletta för att stödja beslutsprocesser i tillräcklig utsträckning i verkligheten. För närvarande förutsätts, t.ex. ofta att användaren själv klarar av att specificera och utföra utvinningen (eliciteringen) av input data. Detta involverar dock ett antal problematiska delar och dess kvalité är av vikt för hela processen. Denna avhandling fokuserar på mer praktiskt användbar elicitering av information i beslutsanalys-applikationer än vad som finns att tillgå idag. En processmodell som betonar vikten av strukturerad elicitering av adekvata indata genom hela beslutsprocessen föreslås också. För att ytterligare definiera de problematiska aspekterna av elicitering utfördes tre empiriska studier. Problemen med att utvinna precisa beslutsdata antyder att användandet av oprecisa värden inom elicitering är en mer realistisk och användbar ansats att sträva efter. Baserat på teori och resultaten av studierna formaliserades en vikteliciterings-metod för oprecisa utlåtanden och osäkra indata i Cardinal Rank Ordering of Criteria (CROC) metoden. Metoden är både kompatibel med en anpassad preskriptiv beslutsmodell fokuserad på en mer strukturerad eliciteringskomponent samt algoritmer för att hantera denna typ av data. CROC-metoden användes och validerades i två riktiga fall, vilket inte är så vanligt inom beslutsanalys forskning. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 7: Submitted. </p>
370

Decision Aid for Planning Local Energy Systems : Application of Multi-Criteria Decision Analysis

Catrinu, Maria January 2006 (has links)
Planning is what sustains an energy system. It is a process of analysis and ongoing decision making about what resources and energy technologies to use when supplying energy to society. This research focuses on integrated energy systems, i.e. systems that are comprised of several energy carriers – electricity, gas, hot water - and energy distribution networks. The planning of these kinds of systems is a complex process, influenced by many factors, among which the most important are the availability of energy resources and the competition between different energy carriers in satisfying energy demand. During the last 10-20 years significant changes have taken place on the world energy scene, which have important implications for energy planning. Two main factors have triggered these changes. The first factor is the immediate need to address environmental changes or more generally, to take measures that are sustainable in the long run. Sustainability can be defined in many ways and in relation to different issues such as economic and ecologic development, reduction of greenhouse gases, responsible use of natural resources, social equity, etc. In recent years, an increased awareness of these issues has been observed at all levels of the society. The second factor is the deregulation of national energy sectors in more than 50 countries. This process brought changes in the ownership of different parts of the formerly integrated energy systems. New business opportunities were created in power generation, wholesale power/gas trading and energy retailing, while the energy infrastructures remained state owned or/and under regulatory control. The newly created energy markets (many of them international) have attracted both new players (power, oil and gas companies and financial institutions) together with the old ones (integrated utilities). In parallel with this vertical separation of national energy sectors, recent studies have shown a tendency for horizontal integration at the regional/company level. For instance, in order to reduce their overall business risk, companies prefer to participate in several segments of the energy value chain (in both regulated and non-regulated activities), and often across more than one fuel commodity, such as gas and electricity or district heating. In this context, the competition between different energy carriers in satisfying the end-use energy demand became obvious in economic as well as in technological and environmental terms. Traditionally, in integrated planning, this competition did not play a big role, since the same state entity made decisions at both national and regional levels. However, in the post-deregulation era it is no longer obvious who the planner is. In many cases, planning decision at local levels involve at least three main interest groups: energy companies (and/or other investors), the state and the local community. This thesis is motivated by the need to help planners to cope with the changes in concepts and values concerning the planning of local energy supply systems. This thesis has two aims. The first aim is to improve the understanding of what planning of local systems implies and how such a process can be structured. The second aim is to contribute to the development of decision support methodologies and tools that can cope with the needs in planning. For this purpose, the use of energy modelling and Multi- Criteria Decision Analysis has been studied.

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