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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

Les déterminants organisationnels de l'adoption de la rétroaction multisource par les organisations

Burcea, Alina Elena January 2006 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
2

Coordination de systèmes multisources pour favoriser la production d’énergie électrique renouvelable / Coordination of multisource systems to support the production of renewable electricity

Chalal, Lamine 14 March 2013 (has links)
Cette thèse est consacrée à la supervision des systèmes de production d’énergie électrique hybrides composés de différents types de sources incluant des sources renouvelables ainsi que des éléments de stockage (batterie). Le chapitre I est consacré à l’état de l’art de la supervision de ce type de systèmes hybrides. Au cours de ce chapitre nous avons défini le contexte et le cadre de notre étude et nous avons présenté les avantages et les inconvénients des stratégies actuellement utilisées. Ensuite, nous avons présenté notre vision de la supervision des systèmes multisources intégrant des ressources renouvelables. Au cours du chapitre II nous avons spécifié le système hybride et les modèles de ses composants afin de les intégrer dans une structure de supervision. La chapitre III concerne le développement du superviseur que nous proposons à base de commande prédictive. L’objectif est de déterminer la meilleure répartition, au sens d’un critère que nous avons proposé, des puissances à fournir par les sources pour répondre à une demande de la charge. La fonction définie pour l’optimisation, correspond au coût de production ; elle prend en compte non seulement le suivi des consignes mais aussi des critères technico-économiques (coût de l’énergie, émissions polluantes, cyclage de l’élément de stockage …etc). Ce superviseur s’appuie sur des modèles dynamiques des sources et des éléments de stockage ainsi que sur les prédictions à court terme de la ressource photovoltaïque. Le critère est minimisé pour chaque nouvelle fenêtre de prédiction afin d’envoyer les consignes à chaque composant du système hybride. Les résultats expérimentaux montrent la validité du superviseur proposé et de l’algorithme associé. Le chapitre IV vise à montrer la généricité du superviseur à base de commande prédictive proposé. En effet, une éolienne contrôlée en zone d’optimisation a été ajoutée au système hybride. Ensuite, l’éolienne est contrôlée en mode dégradé dans le but de réduire l’impact des variations de la vitesse du vent sur le suivi de la consigne de puissance. La fonction coût a été modifiée pour répondre à ces nouvelles exigences. Enfin, nous avons explicité les bénéfices potentiels d’un horizon de prédiction variable. La variation de l’horizon de prédiction est effectuée en fonction de la pertinence des prévisions des ressources d’origine renouvelable. Les essais sur une plate-forme expérimentale, combinant des composants réels et des modèles simulés en temps réel (Model-in-the-loop) montrent la validité de tous les concepts développés. / This thesis is devoted to the supervision of the hybrid power generation system composed of various types of sources including renewable sources and electrochemical storage elements. Chapter I is devoted to the state of the art of supervision of such hybrid systems. In this chapter, the context and the scope of our study are defined and the advantages-disadvantages of each such strategy are presented. Our vision for the supervision of a multi-sources system that integrates sources of renewable resources is presented thereafter. In Chapter II we specify the hybrid system and the models of each component in order to integrate them into a supervision structure. Chapter III deals with the design of a supervisory predictive controller which optimizes the power flow of a renewable hybrid system (solar panels, micro-turbine and battery). Short time predictions of the solar power and the power reference are embedded in the supervisor. The performance index integrates the environmental impact, the cost of fuel, battery cycling and the energy delivery. Simulations and a real-time application of a model-in-the-Loop plant are carried out to illustrate the applicability and electiveness of the proposed supervisory predictive control design. Chapter IV aims to show the generic properties of the proposed supervisory system. In fact, a wind turbine has been added to the hybrid system and the cost function has been modified. The real-time simulations show the effectiveness of the proposed power management system. Then, the turbine is controlled in degraded mode in order to reduce the impact of wind speed fluctuation with respect to the power reference. The cost function has been modified to meet these new requirements. Finally, the potential benefits of considering a dynamic prediction horizon are explained. The variation of the prediction horizon is performed according to the relevance of the predictions of renewable resources. Tested on an experimental platform combining real components and real-time simulation models (Model-in-the-loop), the results show the validity of all the developed concepts.
3

Combined Spatial-Spectral Processing of Multisource Data Using Thematic Content

Filiberti, Daniel Paul January 2005 (has links)
In this dissertation, I design a processing approach, implement and test several solutions to combining spatial and spectral processing of multisource data. The measured spectral information is assumed to come from a multispectral or hyperspectral imaging system with low spatial resolution. Thematic content from a higher spatial resolution sensor is used to spatially localize different materials by their spectral signature. This approach results in both spectralunmixing and sharpening, a spatial-spectral fusion. The main real imagery example, fusion of polarimetric synthetic aperture radar (SAR) with hyperspectral imagery, poses a unique challenge due to the phenomenological differences between the sensors.Theoretical models for electro-optical image formation and scene reflectivity are shown to lead naturally to a set of pixel mixing equations. Several solutions for the spatial unmixing form of these equations are examined, based on the method of least squares. In particular, a method for introducing thematic content into the solution for spatial unmixing is defined using weighted least squares. Finally, and most significantly, a spatial-spectral fusion algorithm based on the theory of projection onto convex sets (POCS) is presented. Theoretical aspects of POCS are briefly discussed, showing how the use of constraints in the form of closed convex sets drives the solution. Then, constraints are derived that are intimately tied to the underlying theoretical models. Simulated imagery is used to characterize the different constraintcombinations that can be used in a POCS-based fusion algorithm.The fusion algorithms are applied to real imagery from two data sets, a Landsat ETM+ scene over Tucson, AZ and an AVIRIS/AirSAR scene over Tombstone, AZ. The results of the fusion are analyzed using scattergrams and correlation statistics. The POCS-based fusion algorithm is shown to produce a reasonable fusion of the AVIRIS/AirSAR data, with some sharpening of spatial-spectral features.
4

MULTISOURCE FEEDBACK LEADERSHIP RATINGS: ANALYZING FOR MEASUREMENT INVARIANCE AND COMPARING RATER GROUP IMPLICIT LEADERSHIP THEORIES

Gower, Kim 07 May 2012 (has links)
This research outlines a conceptual framework and data analysis process to examine multisource feedback (MSF) rater group differences from a leadership assessment survey, after testing the measures for equivalence. MSF gathers and compares ratings from supervisors, peer, followers and self and is the predominant leadership assessment tool in the United States. The results of MSF determine significant professional outcomes such as leadership development opportunities, promotions and compensation. An underlying belief behind the extensive use of MSF is that each rater group has a different set of implicit leadership theories (ILTs) they use when assessing the leader, and therefore each group is able to contribute unique insight. If this is true, research findings would find rater group consistency in leadership assessment outcomes, but they do not. A review of group comparison research reveals that most empirical MSF studies fail to perform preliminary data exploration, employ consistent models or adequately test for measurement equivalence (ME); yet industry standards strongly suggest exploratory methods whenever data sets undergo changes, and misspecified models cause biased results. Finally, ME testing is critical to ascertain if rater groups have similar conceptualizations of the factors and items in an MSF survey. If conceptual ME is not established, substantive group comparisons cannot be made. This study draws on the extant MSF, ILT and ME literature and analyzes rater group data from a large, application-based MSF leadership database. After exploring the data and running the requisite MI tests, I found that the measures upheld measurement invariance and were suitable for group comparison. Additional MI tests for substantive hypotheses support found that significant mean differences did exist among certain rater groups and dimensions, but only direct report and peer groups were consistently significantly different in all four dimensions (analytical, interpersonal, courageous and leadership effectiveness). Additionally, the interpersonal dimension was the most highly correlated with leadership effectiveness in all five rater groups. The overall findings of this study address the importance of MSF data exploration, offer alternative explanations to the disparate leadership MSF research findings to date and question the application use of MSF tools in their current form.
5

Developing novel techniques for next generation rotating shield brachytherapy

Dadkhah, Hossein 01 August 2017 (has links)
Multi-helix rotating shield brachytherapy (RSBT) applicator and multi-source RSBT apparatus are two novel intensity-modulated brachytherapy techniques for the treatment of cervical and prostate cancer, respectively. The use of imaging techniques such as magnetic resonance imaging guided brachytherapy has enabled the precise identification and contouring of tumor volumes for treatment planning, as well as demonstrated the challenges associated with using conventional high dose rate brachytherapy (HDR-BT) approaches to conform the radiation dose to the target and avoid surrounding sensitive healthy tissues. The target conformity of conventional HDR-BT dose distributions is restricted based on the geometrical constraints imposed by the position and shape of the tube-shaped applicators, as well as the radially-symmetric radiation dose distributions produced by the radiation sources. Dose distribution conformity for cervical and prostate cancer can be significantly improved relative to conventional HDR-BT through the use of multi-helix and multi-source RSBT techniques, respectively. In this study, two novel RSBT concepts for treating cervical and prostate cancer were introduced and the dosimetric impact was evaluated. A Henschke-type cervical cancer applicator, designed for an electronic brachytherapy (eBx) source (Xoft AxxentTM) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles, is proposed. The interior wall of the applicator contains six evenly-spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly-distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. RSBT treatment plans were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. Treatment delivery time and tumor coverage (D90 of HR-CTV) were the two metrics used as the basis for evaluation and comparison. With multi-source RSBT apparatus, precise angular and linear positioning of partially-shielded 153Gd brachytherapy sources in interstitial needles for the treatment of locally-advanced prostate cancer is carried out. Following needle implantation through the patient template, an angular drive mechanism is docked to the patient template. Each needle is coupled to a multisource afterloader catheter by a connector passing through a shaft. The shafts are rotated about their axes by translating a moving template between two stationary templates. Shafts’ surfaces and moving template holes are helically threaded with the same pattern such that translation of the moving template causes simultaneous rotation of the shafts. The catheter angles are simultaneously incremented throughout treatment. For each rotation angle, source depth in each needle is controlled by a multisource afterloader, which is proposed as an array of belt-driven linear actuators, each of which drives a wire that controls catheter depth in a needle. In conclusion, the helical RSBT approach for treating cervical cancer and the multi-catheter RSBT approach for treating prostate cancer, powered with novel radiation sources amenable to shielding, are clinically- and mechanically-feasible techniques that dosimetrically outperform conventional brachytherapy methods while minimizing damage to healthy tissues inside and/or adjacent to the target.
6

Numbers, words and anonymity in 360-degree feedback : a qualitative study

Harrington, Amanda January 2013 (has links)
Academic research in 360-degree feedback continues to be dominated by a positivist approach with analyses of the feedback ratings. In contrast, this qualitative study explores how people make sense of 360, across the chain of meaning making involving not only raters and feedback recipients but also HR managers, facilitators and external consultants. Two corporate case studies in the pharmaceutical sector show how 360 evolves as a social process and carries a variety of meanings in different organisations and management contexts. Quasi-scientific rituals are revealed, demonstrating the existence of pseudo-anonymity and of complex use of numerical ratings and narrative comments. Woven alongside these corporate case studies is an autoethnography, which examines emotional and cognitive responses to two rounds of 360 asking for feedback on coaching performance. The autoethnographic thread allows insights into the dynamic relationship between academic and practitioner perspectives, as the researcher moves between both worlds. This PhD makes three contributions: the conceptualisation of 360 as a social process; the questioning of taken-for-granted customs within 360; and a methodological contribution to the development of autoethnographic practice.
7

Least-squares Migration and Full Waveform Inversion with Multisource Frequency Selection

Huang, Yunsong 09 1900 (has links)
Multisource Least-Squares Migration (LSM) of phase-encoded supergathers has shown great promise in reducing the computational cost of conventional migration. But for the marine acquisition geometry this approach faces the challenge of erroneous misfit due to the mismatch between the limited number of live traces/shot recorded in the field and the pervasive number of traces generated by the finite-difference modeling method. To tackle this mismatch problem, I present a frequency selection strategy with LSM of supergathers. The key idea is, at each LSM iteration, to assign a unique frequency band to each shot gather, so that the spectral overlap among those shots—and therefore their crosstallk—is zero. Consequently, each receiver can unambiguously identify and then discount the superfluous sources—those that are not associated with the receiver in marine acquisition. To compare with standard migration, I apply the proposed method to 2D SEG/EAGE salt model and obtain better resolved images computed at about 1/8 the cost; results for 3D SEG/EAGE salt model, with Ocean Bottom Seismometer (OBS) survey, show a speedup of 40×. This strategy is next extended to multisource Full Waveform Inversion (FWI) of supergathers for marine streamer data, with the same advantages of computational efficiency and storage savings. In the Finite-Difference Time-Domain (FDTD) method, to mitigate spectral leakage due to delayed onsets of sine waves detected at receivers, I double the simulation time and retain only the second half of the simulated records. To compare with standard FWI, I apply the proposed method to 2D velocity model of SEG/EAGE salt and to Gulf Of Mexico (GOM) field data, and obtain a speedup of about 4× and 8×. Formulas are then derived for the resolution limits of various constituent wavepaths pertaining to FWI: diving waves, primary reflections, diffractions, and multiple reflections. They suggest that inverting multiples can provide some low and intermediate-wavenumber components of the velocity model not available in the primaries. In addition, diffractions can provide twice or better the resolution as specular reflections for comparable depths of the reflector and diffractor. The width of the diffraction-transmission wavepath is on the order of λ at the diffractor location for the diffraction-transmission wavepath.
8

FUZZY MARKOV RANDOM FIELDS FOR OPTICAL AND MICROWAVE REMOTE SENSING IMAGE ANALYSIS : SUPER RESOLUTION MAPPING (SRM) AND MULTISOURCE IMAGE CLASSIFICATION (MIC) / ファジーマルコフ確率場による光学およびマイクロ波リモートセンシング画像解析 : 超解像度マッピングと複数センサ画像分類

Duminda Ranganath Welikanna 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18561号 / 工博第3922号 / 新制||工||1603(附属図書館) / 31461 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 田村 正行, 准教授 須﨑 純一, 准教授 田中 賢治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
9

Systèmes multisources de récupération d'énergie dans l'environnement humain : modélisation et optimisation du dimensionnement / Multisource systems for harvesting energy in the human environment : modeling and sizing optimization

Lossec, Marianne 07 July 2011 (has links)
Ces travaux s'inscrivent dans la problématique de l'alimentation autonome de systèmes électroniques communicants fondée sur la récupération de l'énergie disponible dans l'environnement humain. Cette thèse traite du dimensionnement d'un générateur multisource (thermique, photovoltaïque et cinétique) avec stockage d'énergie. Afin d'optimiser le dimensionnement d'un tel système dans un contexte de ressources paramétrables, des modèles génériques, adaptés à une large plage de dimensions, ont été établis, à partir de technologies déjà existantes, et validés expérimentalement. L'approche système a permis d'étudier les nombreux couplages multiphysiques existants et de mieux dimensionner le système. Ainsi, il a été montré qu'optimiser le rendement global de toute la chaîne de conversion d'énergie conduit à des solutions différentes de celles résultant d'une optimisation du dimensionnement de chaque organe pris séparément. Enfin, dans la dernière partie de cette thèse, une étude a été menée sur l'impact du profil de consommation sur le dimensionnement du système. Cette étude a permis, sur le cas particulier d'une application réelle, de mettre en évidence le potentiel d'une gestion d'énergie en cas de ressources faibles notamment par l'adaptation des profils de consommation. / This work deals with the problematic of self-powered communicating electronic systems based onenergy harvesting in the human environment. This thesis addresses the sizing of a multisource generator(thermal, photovoltaic and kinetic) with energy storage. To optimize the sizing of such a systemin the context of configurable resources, generic models, adapted to a wide range of dimensions, wereestablished from existing technology, and validated experimentally. The system-level approach wasused to study the many existing multiphysics couplings to better size the system. Thus, it was shownthat optimizing the global efficiency of the whole energy conversion chain leads to solutions differentfrom those resulting from sizing optimization of each component separately. Finally, in the latter partof this thesis, a study was conducted on the impact of load profil on the sizing of the system. Thisstudy, on the particular case of a real application, highlight the potential for energy management inthe case of poor ressources, notably by adapting the load profils.
10

APLICAÇÃO DO CLASSIFICADOR SVM E DADOS ALTIMÉTRICOS NA ESPACIALIZAÇÃO DE CLASSES DE VEGETAÇÃO NUMA PORÇÃO LITORÂNEA DO ESTADO DO PARANÁ

Roza, Willian Samuel Santana da 27 March 2014 (has links)
Made available in DSpace on 2017-07-21T18:15:37Z (GMT). No. of bitstreams: 1 Willian Roza.pdf: 6684537 bytes, checksum: fafdba4f5d553667283cb6cbe3e7f121 (MD5) Previous issue date: 2014-03-27 / The Atlantic Forest displays many functions that ensure the quality of life for many Brazilians and corresponds to one of the 34 hotspots of biodiversity in the world. In the State of Paraná, areas with the largest remnants of Atlantic Forest are located in the eastern portion of the state, which correspond to the Dense Tropical Rainforest (DTR); it presents the following physiognomic units: ecological forest, alluvial, lowland, submontane, montane and upper montane and non-forest represented by pioneer formations: mangroves, salt fields, salt marshes and refuges vegetation. This study seeks to test strategies to spatialize forest and non-forest remnants of ecological physiognomic units of DTR in the southeastern portion of the State of Paraná. In order to spatialize the vegetation, digital classification through the algorithm Support Vector Machines (SVM) was used. Tests were conducted on Landsat 5 TM spectral bands and ancillary altitude data such as the DEM (Digital Elevation Model) and ASTER (Advanced Spaceborne Thermal Emission Reflection Radiometer) with its byproducts, namely slope and altimetric tracks. First tests were undertaken only with the spectral bands, followed by ones with the spectral bands and ancillary altitude data; and finally the last ones with different SVM settings. To calculate the accuracy of the classified images through Kappa Index (KI) and Confusion Matrix (CM), training samples were collected in images from sensors Spot 5 and P6LIS3, and altitude was verified by means of DEM SRTM (Shuttle Radar Topography Mission). After visual analysis, overall results and classes corresponding to the results from classified images, it was found that just with the spectral bands it was not possible to spatialize forest remnants from ecological physiognomic units of DTR. I was concluded that the separation between the classes of DTR (upper montane, montane, submontane and lowland) was not adequate. But, still observed through visual analysis, there was an accuracy improvement in digital classification when using spectral bands plus DEM ASTER. It seems that the most appropriate result from visual analysis and accuracy of the classified images were obtained through classifying spectral bands over altimetric tracks, enabling GIS to measure the values of the areas in the physiognomic units of DTR. It is noteworthy that all classifications were appropriate, however with the auxiliary altitude data, accuracy was increased in visual analysis, IK and MC by the aid of comparing them to altimetric tracks that define the position of the vegetation according to relief classes as addressed by Veloso, Rangel Filho and Lima (1991). This study serves as a resource for identifying, spatializing and mapping the distribution of forest and non-forest remnants in the southeastern portion of the Paraná DTR. This region encompasses several protected areas, located at both floodplains and slopes of the coastal mountain range. / A Mata Atlântica possui diversas funções que garantem a qualidade de vida de inúmeros brasileiros, sendo que corresponde a um dos 34 hotspots de biodiversidade do mundo. No Paraná, as áreas que apresentam os maiores remanescentes de Mata Atlântica estão situadas na porção leste do estado, as quais correspondem à Floresta Ombrófila Densa (FOD), que apresenta as seguintes unidades fisionômicas ecológicas florestais: aluvial, terras baixas, submontana, montana e alto-montana; e as não florestais, representadas pelas formações pioneiras: manguezais, campos salinos, restingas e refúgios vegetacionais. A presente pesquisa tem como objetivo testar estratégias para espacializar os remanescentes florestais e não florestais das unidades fisionômicas ecológicas da porção sudeste da FOD do estado do Paraná. Para espacializar a vegetação, optou-se pela classificação digital mediante o algoritmo Support Vector Machines (SVM), com o qual se realizaram testes com as bandas espectrais Landsat 5 TM e dados auxiliares de altitude, como o MDE (Modelo Digital de Elevação) ASTER (Advanced Spaceborne Thermal Emission Reflection Radiometer) e seus subprodutos, declividade e faixas altimétricas. Realizaram-se os primeiros testes somente com as bandas espectrais, em seguida com as bandas espectrais e dados auxiliares de altitude e, por último, os testes com diferentes configurações de SVM. Para calcular a acuracidade mediante Índice Kappa (IK) e Matriz de Confusão (MC) das imagens classificadas, amostras de treinamento foram coletadas em imagens do sensor Spot 5 e P6LIS3, sendo que se verificou a altitude mediante MDE SRTM (Shuttle Radar Topography Mission). Após as análises visuais, acuracidades globais e de classes correspondentes aos resultados das imagens classificadas, constatou-se que somente com as bandas espectrais não é possível espacializar os remanescentes florestais das unidades fisionômicas ecológicas da FOD, pois a separação entre as classes da FOD (alto-montana, montana, submontana e terras baixas) não foi adequada. Porém, quando da classificação digital com as bandas espectrais mais MDE ASTER, contata-se, mediante a análise visual e acuracidade das imagens classificadas, que o resultado melhorou. Nota-se que o resultado mais adequado a partir das análises visuais e acuracidade das imagens classificadas foi obtido mediante a classificação com as bandas espectrais mais faixas altimétricas, possibilitando, em SIG, mensurar os valores de áreas das unidades fisionômicas ecológicas florestais da FOD. Constata-se que todas as classificações são adequadas, no entanto, com os dados auxiliares de altitude, a acuracidade aumenta tanto pela análise visual quanto pelos IK e MC, mediante a comparação com as faixas altimétricas que definem a posição da vegetação de acordo com as classes do relevo abordadas por Veloso, Rangel Filho e Lima (1991). O presente trabalho serve como subsídio para a identificação, espacialização e mapeamentos dos remanescentes florestais e não florestais da porção sudeste da FOD do Paraná que abrangem várias unidades de conservação, situadas tanto na planície aluvial quanto nas encostas da Serra do Mar.

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