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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.
21

Prestationsmätning i komplexa projekt : - En fallstudie på Saab Aeronautics / Performance measurement in complex projects : – A case study at Saab Aeronautics

Kanmert, Jacob, Lindh, Joakim, Welin, Joel January 2018 (has links)
Organisationer med komplexa projekt som sträcker sig över ett flertal år finner svårigheter att förhålla sig till projektens fördefinierade parametrar tid, kostnad och omfattning. Skenande kostnader och förseningar är vanligt förekommande i dessa typer av projekt, då projekten omfattar ett samspel av ett flertal aktiviteter och där projektets omfattning ofta förändras. Det finns metoder som verksamheter kan tillämpa för att kontrollera ovannämnda parametrar och i ett tidigt skede kunna identifiera när någon av parametrar tenderar att överskridas. En metod som styrker prestationsmätningar är Earned Value Mangament, EVM. Syftet med studien var att identifiera vart organisationer brister gentemot branschstandarden inom EVM, ANSI/EIA-748. Standarden innehåller viktiga steg för att kunna utföra en korrekt prestationsmätning tillsammans med teorin från Earned Value Management. Resultat studien presentera indikerar på att organisationer måste skapa tydliga riktlinjer hur ANSI/EIA-748 skall tillämpas. Till exempel att alla bryter ner arbetet och fördelar sina budgetar på samma sätt. Studiens resultat antyder också att Rolling Wave är ett lämpligt verktyg för komplexa och långa projekt. Av den anledningen att projektledare inte planerar för mycket i onödan eftersom projektets omfattning ständigt förändras.
22

Heart Rate Variability Extraction from Video Signals

Alghoul, Karim January 2015 (has links)
Heart Rate Variability (HRV) analysis has been garnering attention from researchers due to its wide range of applications. Medical researchers have always been interested in Heart Rate (HR) and HRV analysis, but nowadays, investigators from variety of other fields are also probing the subject. For instance, variation in HR and HRV is connected to emotional arousal. Therefore, knowledge from the fields of affective computing and psychology, can be employed to devise machines that understand the emotional states of humans. Recent advancements in non-contact HR and HRV measurement techniques will likely further boost interest in emotional estimation through . Such measurement methods involve the extraction of the photoplethysmography (PPG) signal from the human's face through a camera. The latest approaches apply Independent Component Analysis (ICA) on the color channels of video recordings to extract a PPG signal. Other investigated methods rely on Eulerian Video Magnification (EVM) to detect subtle changes in skin color associated with PPG. The effectiveness of the EVM in HR estimation has well been established. However, to the best of our knowledge, EVM has not been successfully employed to extract HRV feature from a video of a human face. In contrast, ICA based methods have been successfully used for HRV analysis. As we demonstrate in this thesis, these two approaches for HRV feature extraction are highly sensitive to noise. Hence, when we evaluated them in indoor settings, we obtained mean absolute error in the range of 0.012 and 28.4. Therefore, in this thesis, we present two approaches to minimize the error rate when estimating physiological measurements from recorded facial videos using a standard camera. In our first approach which is based on the EVM method, we succeeded in extracting HRV measurements but we could not get rid of high frequency noise, which resulted in a high error percentage for the result of the High frequency (HF) component. Our second proposed approach solved this issue by applying ICA on the red, green and blue (RGB) colors channels and we were able to achieve lower error rates and less noisy signal as compared to previous related works. This was done by using a Buterworth filter with the subject's specific HR range as its Cut-Off. The methods were tested with 12 subjects from the DISCOVER lab at the University of Ottawa, using artificial lights as the only source of illumination. This made it a challenge for us because artificial light produces HF signals which can interfere with the PPG signal. The final results show that our proposed ICA based method has a mean absolute error (MAE) of 0.006, 0.005, 0.34, 0.57 and 0.419 for the mean HR, mean RR, LF, HF and LF/HF respectively. This approach also shows that these physiological parameters are highly correlated with the results taken from the electrocardiography (ECG).
23

Electronic Voting; A Possible Solution for Sub-Saharan Africa? : <em>A focus on the Ghanaian Electoral System</em>

Gyimah, Nana Afua Boamah, Tita, Bertrand Asongwe January 2010 (has links)
<p>One of the major reasons for political instability in Sub-Saharan Africa originates from the way elections are conducted. Most African countries have quite a handful of electoral malpractices which lead to political instability, civil wars and low economic growth.  Electronic voting might be a solution to the election problems and thus bring in a stable political atmosphere which attracts investors.</p><p>This thesis looks at the prospects and challenges of implementing e-voting in Ghana and Sub-Saharan Africa as a solution to the current manual paper-based system and proposes a framework and requirements which can be used as guidelines for its adoption and implementation.</p><p>The thesis has been conducted by studying literature on electronic voting and Diffusion of Innovations Theory. Furthermore, a case study has been conducted on the Ghanaian electoral process, by conducting interviews with the Danquah Institute of Ghana and through questionnaires to some Ghanaian citizens in both the rural and urban areas of Ghana.</p><p>The main results from the thesis show that the adoption and subsequent implementation of e-voting in SSA countries, can only be possible if the governments show strong committment and support by securing funds through donor organizations, and providing the necessary IT infrastructure and other resources needed to support the project. Voter education too is an absolute necessity. The adoption of e-voting is mainly based on how the innovation will be diffused and the perceived benefits that will be derived from the investment. Hence, particular attention should be paid to the various communication channels, especially the media, through which messages are passed across to the citizens.</p>
24

ETUDE DE L'IMPACT DU FILTRAGE ET DES NON-LINEARITES SUR LES SIGNAUX ULB DANS LES FRONT-END RADIO-FREQUENCE ET LES RESEAUX HYBRIDES OPTIQUE-RADIO

Lombard, Philippe 03 December 2007 (has links) (PDF)
Les systèmes Ultra Larges Bandes (ULB) représentent une nouvelle technologie de communication sans fil pour la transmission d'informations à très hauts débits. Avec une Densité Spectrale de Puissance (DSP) inférieure à -41.3 dBm/MHz, les distances de propagation sont considérablement restreintes (< 20 m). C'est en février 2002, que la commission fédérale de communication des Etats-Unis (FCC) a alloué pour les systèmes ULB une bande de fréquence comprise entre 3,1 et 10,6 GHz. Depuis, de nombreuses divergences sont apparues suivant les grandes zones géographiques de normalisation.<br />Au travers des nombreuses techniques de transmission ULB, nous étudions la modulation multi-bandes à répétition en fréquence orthogonale (MB-OFDM) qui a été proposée par l'European Computing Machineries Association (ECMA) en temps que standard en 2005.L'efficacité des signaux Impulsionnel Radio (IR), précurseur à l'ULB, a cependant été montrée. Nous présentons à ce titre une topologie originale nommée Multi-Bandes On-Off Keying (MB-OOK).<br />Dans le cadre de cette thèse, nous développons un outil de simulation système (SST) afin d'analyser les performances d'un système ULB-OFDM. Nous étudions l'influence sur le taux d'erreur binaire (BER) des non-linéarités du front-end de réception Radio-Fréquence (RF) et de l'amplification de puissance faible bruit (LNA) dans une chaîne de transmission globale.<br />Dans le cadre des systèmes MB-OOK, différents types de filtres sont envisagés. L'impact sur le BER est étudié afin de connaître les propriétés prédominantes des filtres sur les performances de transmission.<br />Le domaine de l'optique peut également être avantageusement employé dans des processus de transmission ULB. Les réseaux larges bandes radio sur fibres (RoF) présentent de nombreux intérêts pour fournir à moindre coût la distribution du signal mais également la possibilité de pouvoir le traiter directement. Dans ce sens, Nous évaluons les possibilités de convertir fréquentiellement des signaux de type ULB-OFDM, ainsi que d'évaluer l'impact de transmetteurs Electrique/Optique (E/O) sur les performances d'un système ULB sur fibre à partir des valeurs du vecteur d'erreur d'amplitude (EVM).
25

Electronic Voting; A Possible Solution for Sub-Saharan Africa? : A focus on the Ghanaian Electoral System

Gyimah, Nana Afua Boamah, Tita, Bertrand Asongwe January 2010 (has links)
One of the major reasons for political instability in Sub-Saharan Africa originates from the way elections are conducted. Most African countries have quite a handful of electoral malpractices which lead to political instability, civil wars and low economic growth.  Electronic voting might be a solution to the election problems and thus bring in a stable political atmosphere which attracts investors. This thesis looks at the prospects and challenges of implementing e-voting in Ghana and Sub-Saharan Africa as a solution to the current manual paper-based system and proposes a framework and requirements which can be used as guidelines for its adoption and implementation. The thesis has been conducted by studying literature on electronic voting and Diffusion of Innovations Theory. Furthermore, a case study has been conducted on the Ghanaian electoral process, by conducting interviews with the Danquah Institute of Ghana and through questionnaires to some Ghanaian citizens in both the rural and urban areas of Ghana. The main results from the thesis show that the adoption and subsequent implementation of e-voting in SSA countries, can only be possible if the governments show strong committment and support by securing funds through donor organizations, and providing the necessary IT infrastructure and other resources needed to support the project. Voter education too is an absolute necessity. The adoption of e-voting is mainly based on how the innovation will be diffused and the perceived benefits that will be derived from the investment. Hence, particular attention should be paid to the various communication channels, especially the media, through which messages are passed across to the citizens.
26

Analytical anaysis of in-band and out-of-band distorsions for multicarrier signals : Impact of non-linear amplification, memory effects and predistorsion / Analyse théorique des distorsions dans la bande et en dehors de la bande de transmission pour les signaux à porteuses multiples : Impact conjoint des non-linéarités de l'amplificateur de puissance et effets de mémoire et prédistorsion

Cheaito, Ali 10 March 2017 (has links)
Les techniques multiporteuses de type OFDM sont aujourd'hui largement déployées dans tous les systèmes de communication sans fils notamment dans les réseaux cellulaires (L TE), les réseaux de diffusion (DVB) ou encore les réseaux WiFi. Cependant, les modulations multiporteuses se caractérisent par une très grande dynamique mesurée par le Peak to Average Power Ratio (PAPR), ce qui empêche d'alimenter l'amplificateur de puissance non linéaire (utilisé avant l'émission des signaux) à son point optimal et ainsi conduit à diminuer son efficacité énergétique. Des techniques de réduction du PAPR peuvent alors être mises en oeuvre pour réduire le PAPR du signal et des techniques de prédistorsion peuvent alors être utilisées pour compenser les non-linéarités de l'amplificateur de puissance. L'approche développée dans le cadre de cette thèse a pour objectif d'étudier une solution intelligente pour les implémentations futures pour contrôler la réduction du PAPR et les étapes de linéa risation de manière flexible en fonction de certains paramètres prédéfinis afin qu'ils deviennent adaptatifs et auto-configurables. Plus précisément, notre travail a principalement porté sur l'analyse des différentes distorsions dans la bande (in-band distortions)mesurées par I'EVM ou Error Vector Magnitude et en dehors de la bande de transmission (out-of-band distortions) mesurées par I'ACPR ou Adjacent Channel Power Ratio de signaux à porteuses multiples. En particulier de nombreux résultats analytiques complétés par des résultats de simulation permettant d'évaluer I'EVM et I'ACPR en fonction des caractéristiques de l'amplification nonlinéaire en prenant en compte ou pas l'effet mémoire de l'amplificateur et la mise en oeuvre de techniques d'écrêtage et de pré-distorsion ont été obtenus. Ces résultats constituent une étape importante dans l'optimisation globale de la complexité, de la linéarité et de l'efficacité énergétique des émetteurs aussi bien pour la diffusion de la télévision numérique que pour les réseaux cellulaires de 4 ème génération (L TE) ou de 5""' génération. / OFDM multicarrier techniques are now widely deployed in most wireless communication systems, in particular in cellularnetworks (L TE), broadcast networks (DVB) and WiFi networks. However, multi-carrier modulations are characterized by avery large dynamic amplitude measured by the Peak to Average Power Ratio (PAPR). which prevents radio frequencydesigners to feed the signal at the optimal point of the Power Amplifier (PA) which reduces the PA energy efficiency. Inliterature, the PAPR reduction and linearization techniques are the main approaches to solve the PAPR problem, the PAnonlinearities problem. as well as the low PA efficiency problem.The approach developed in this thesis was to study an intelligent solution for future implementations to control thereduction of PAPR and the linearization steps in a flexible way according to some predefined parameters so that theybecome adaptive and self-configurable. More specifically, our work focused on the analytical analysis of in-band measureby the Error Vector Magnitude (EVM) and out-of-band distortions measured by the Adjacent Chanel Power Ratio (ACPR)for clipped multicarrier signals taking into account the impact of non-linear amplification, memory effects and predistortion.In particular. many analytical results complemented by simulation results to evaluate the EVM and ACPR are proposed.These analytical expressions depend on the PA characteristics taking into account or not the PA memory effects and theuse of clipping and pre-distortion techniques. lt is worthwhile to note that our proposed theoretical analyses could be veryuseful for optimizing future transmitter efficiency and linearity in the field of broadcasting applications for the deployment oDVB-T2 transmitters as well as for L TE cellular networks.
27

Modelování a řízení projektového portfolia / Modelling and Management of Project Portfolio

Skalníková, Zuzana January 2018 (has links)
This thesis is dedicated to modeling and management of project portfolio. In the first part, project is specified, along with methods for its managing. Next part describes the project portfolio, its managing and aspects that affect it. Thesis continues with analysis and design of software prototype capable of managing project portfolios.  Most suitable methods are selected for project analysis.  Designed prototype is then implemented and solution is described in the thesis. Last part of the work is user testing, which pointed out the functionality and usability of created prototype.
28

Koexistence mobilních komunikačních systémů GSM-EDGE a UMTS / GSM-EDGE and UMTS Systems Coexistence

Gleissner, Filip January 2009 (has links)
The dissertation thesis deals with the investigation of the coexistence of GSM–EDGE and UMTS systems with focus on the physical layer of the systems. The aim is to provide a set of recommendations for practical cooperation while the systems operate in both the separated and the common radio bands. A detailed description of signal processing of both the systems on the physical layer is presented. On the basis of this description, models of both systems were created and implemented in the MATLAB environment. The simulations are focused on the physical layer quality parameters, especially the bit error ratio evaluation for various ratios of useful signal power to noise power during the transmission over the radio channel. Simulation is also used to examine the quality of received useful signal while it is interfered by signals from the same and adjacent channels. The purpose is to determine the isolation between these adjacent channels, when the bit error ratio of the useful signal does not exceed a certain reference value. The simulation results are subsequently subjected to comparison with the results of the experimental measurements in laboratory conditions. Before the measurements are carried out, a study of possible interference types is performed. Consequently, the crucial parameters of the measuring equipment used are verified. From the results of simulations and measurements, the proposal of a minimum and recommended carrier separation between both the systems is presented in order to efficiently utilize the assigned frequency spectrum. Furthermore, for the cooperation in both the separated and the common radio bands, the necessary precautions are given for reaching the required isolation and thereby inter-system interference minimization.
29

Sledování spektra a optimalizace systémů s více nosnými pro kognitivní rádio / Spectrum sensing and multicarrier systems optimization for cognitive radio

Povalač, Karel January 2012 (has links)
The doctoral thesis deals with spectrum sensing and subsequent use of the frequency spectrum by multicarrier communication system, which parameters are set on the basis of the optimization technique. Adaptation settings can be made with respect to several requirements as well as state and occupancy of individual communication channels. The system, which is characterized above is often referred as cognitive radio. Equipments operating on cognitive radio principles will be widely used in the near future, because of frequency spectrum limitation. One of the main contributions of the work is the novel usage of the Kolmogorov – Smirnov statistical test as an alternative detection of primary user signal presence. The new fitness function for Particle Swarm Optimization (PSO) has been introduced and the Error Vector Magnitude (EVM) parameter has been used in the adaptive greedy algorithm and PSO optimization. The dissertation thesis also incorporates information about the reliability of the frequency spectrum sensing in the modified greedy algorithm. The proposed methods are verified by the simulations and the frequency domain energy detection is implemented on the development board with FPGA.
30

Koexistence mobilních komunikačních systémů WLAN a Bluetooth / WLAN and Bluetooth Systems Coexistence

Mikulka, Jan January 2009 (has links)
The dissertation thesis deals with a WLAN and Bluetooth systems coexistence. A Bluetooth standard works in an unlicensed frequency band 2,402 – 2,480 GHz. This frequency band is also used by an IEEE 802.11b/g standard (Wi-Fi) which is the most extended representative of WLAN networks. Because Bluetooth and Wi-Fi systems operate in the same frequency band, a mutual signal degradation may appear, when devices are collocated in the same area. In the first part of the dissertation thesis there is a brief summary of 2,402 - 2,480 GHz frequency band regulations and its usage. There are described physical layers of Bluetooth and IEEE 802.11b/g standards and techniques used for a collision avoidance. The main part of the dissertation thesis deals with a development of a new Matlab Simulink model for investigations of the Bluetooth and Wi-Fi standards coexistence. Physical layer models and results of the coexistence simulations are verified by a measurement in real conditions with a help of a modern vector signal analyzer. The results are presented in a graphical form and a brief summary is attached at the end of each chapter. Corresponding tables of simulated and measured values are available in the enclosed CD.

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