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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

Metody ekvalizace v digitálních komunikačních systémech / Equalization Methods in Digital Communication Systems

Deyneka, Alexander January 2011 (has links)
Tato práce je psaná v angličtině a je zaměřená na problematiku ekvalizace v digitálních komunikačních systémech. Teoretická část zahrnuje stručné pozorování různých způsobů návrhu ekvalizérů. Praktická část se zabývá implementací nejčastěji používaných ekvalizérů a s jejich adaptačními algoritmy. Cílem praktické části je porovnat jejich charakteristiky a odhalit činitele, které ovlivňují kvalitu ekvalizace. V rámci problematiky ekvalizace jsou prozkoumány tři typy ekvalizérů. Lineární ekvalizér, ekvalizér se zpětnou vazbou a ML (Maximum likelihood) ekvalizér. Každý ekvalizér byl testován na modelu, který simuloval reálnou přenosovou soustavu s komplexním zkreslením, která je složena z útlumu, mezisymbolové interference a aditivního šumu. Na základě implenentace byli určeny charakteristiky ekvalizérů a stanoveno že optimální výkon má ML ekvalizér. Adaptační algoritmy hrají významnou roli ve výkonnosti všech zmíněných ekvalizérů. V práci je nastudována skupina stochastických algoritmů jako algoritmus nejmenších čtverců(LMS), Normalizovaný LMS, Variable step-size LMS a algoritmus RLS jako zástupce deterministického přístupu. Bylo zjištěno, že RLS konverguje mnohem rychleji, než algoritmy založené na LMS. Byly nastudovány činitele, které ovlivnili výkon popisovaných algoritmů. Jedním z důležitých činitelů, který ovlivňuje rychlost konvergence a stabilitu algoritmů LMS je parametr velikosti kroku. Dalším velmi důležitým faktorem je výběr trénovací sekvence. Bylo zjištěno, že velkou nevýhodou algoritmů založených na LMS v porovnání s RLS algoritmy je, že kvalita ekvalizace je velmi závislá na spektrální výkonové hustotě a a trénovací sekvenci.
22

Developing green design guidelines: a formal method and case study

Telenko, Cassandra 24 August 2010 (has links)
This thesis describes and demonstrates a method for consolidating, developing, and using green design guidelines for the innovation of greener products. Life cycle analysis (LCA) is one well-accepted tool for quantifying the environmental impacts of a product so designers can identify areas for redesign effort. However, LCA is a retrospective design tool that requires detailed design information that isn’t known until designs are near completion. Alternatively, green design guidelines provide proven techniques for designing greener products. They can be used during the early stages of design, when many decisions fundamental to innovation and environmental impact are made and before LCA is viable. This thesis extends the work already done in green design guidelines, by updating the current knowledge base and introducing a method for extending the set of existing guidelines to encompass new and emerging areas of sustainability. While guidelines have been created from prior experience in design for environment and life cycle analysis, they have not been maintained as a shared and coordinated repertoire of green design solutions. Instead, sets of guidelines are scattered throughout the literature, contain overlaps, operate at different levels of abstraction, and have varying levels of completeness. For example, some areas of green design guidelines, such as design for disassembly, are well established, while other areas of green design guidelines, such as minimizing energy consumption during use, are still being explored. Additionally, while numerous examples of green design guidelines exist, many of the guidelines have no documented validation of their life cycle impacts. The work for this thesis began with the compilation of a dynamic knowledge base of green design guidelines. This set of guidelines is a consolidation and updating of the green design guidelines already available in literature and can be used as a starting poinrt for future improvements and extensions as the field develops. A standard method was then proposed and tested for creating guidelines in currently undeveloped areas of green design, particularly energy consumption during the operation of a product. The method employs reverse engineering techniques and life cycle analysis to identify green requirements and develop corresponding, new green design guidelines. A case study of electric kettles demonstrated the usefulness of the method by yielding four new guidelines and four, corresponding, energy saving re-designs. For this example, the redesigns showed that guidelines can reduce energy consumption, but may incur tradeoffs with other life cycle stages. Calculation of tradeoffs revealed a range of net life cycle impact values that were caused by increased manufacturing demands and variability in consumer use habits. In addition to redesign in the kettle study, the four new guidelines were tested for usefulness in new product design by use of focus groups. Two groups were tasked with designing a new energy efficient toaster concept. Only one group was given the four green design guidelines that were uncovered using the proposed method. The design group using the new green design guidelines produced more viable and practical green features than the design group that did not have the guidelines as a design tool. These preliminary results suggest that the proposed method is useful for creating new guidelines that are beneficial to design teams tackling novel design problems that differ from the original case study. Further work is needed to establish the statistical significance of these results. / text
23

Intégration de règles "DfE" (Design for Environment) pour la conception de produits, process et cycles de vie propres

Alhomsi, Hayder 22 October 2012 (has links) (PDF)
Afin d'aider les concepteurs à considérer l'environnement dans leur projet de conception de produit, tout en minimisant le temps consacré à cette démarche, une évaluation environnementale simplifiée utilisable dès la phase de conception préliminaire a été définie. La démarche proposée vise à intégrer les règles " Design for Environment " (DfE) au plus tôt dans la conception des produits, en proposant une méthode d'évaluation qui traduit ces règles DfE en indicateurs. Pour mener à bien ce travail de thèse, il nous a fallu construire une base des données des Règles DfE, établir une méthode de choix des règles en fonctions du contexte du projet de conception, établir les règles de calcul des indicateurs liés aux règles DfE et mettre en place des représentations adaptées pour l'interprétation des résultats lors de projets de conception. L'objectif ici est de guider le concepteur au plus tôt vers un bon compromis, par des estimations simples. Cette approche est nécessaire afin d'éviter des modifications significatives à la fin des études détaillées et ainsi de nombreuses boucles essais/erreurs en conception. Une étude de cas permet d'illustrer la démarche proposée.
24

Products in environmental management systems : drivers, barriers and experiences

Ammenberg, Jonas, Sundin, Erik January 2005 (has links)
Do standardised environmental management systems (EMS) lead to improved environmental performance? This depends on to what extent these systems lead to changes in important flows of material and energy, which for manufacturing companies, in turn, mean that the product development process is important. Consequently, it appears vital to investigate the connection between EMS and ‘Design for the Environment’ (DFE), i.e. the connection between these management systems and concepts that deal with environmental issues in product development. This paper presents product-oriented environmental management systems (POEMS), including characteristics of existing models, experiences from projects where these models have been tested and experiences concerning the product connection in ‘normal’ EMS. It includes a discussion of important factors influencing to what extent DFE activities are integrated into EMS and/or the outcome of such integration. There are many motives for integrating the two concepts. Firstly, DFE thinking might enrich EMS by contributing with a life-cycle perspective. If EMS encompassed products' life cycles to a greater extent, they would be a better complement to the often facility-oriented legal requirements and authority control. Secondly, EMS might remove the pilot project character of DFE activities and lead to continuous improvement. Thirdly, integration could lead to successful co-operation, both internally and externally. However, existing studies show that there is a mixed picture concerning the extent ‘normal’ EMS currently encompass products.
25

HUR CIRKULÄR EKONOMI KAN IMPLEMENTERAS I SMÅ OCH MEDELSTORA FÖRETAGS PRODUKTUTVECKLING / HOW CIRCULAR ECONOMY CAN BE IMPLEMENTED IN PRODUCT DEVELOPMENT FOR SMALL AND MEDIUM SIZED ENTERPRISES

Dubinovic, Nermin, Nelson, Denny January 2015 (has links)
Dagens trend av industriell tillverkning och konsumtion är av linjär karaktär. Material utvinns, blir produkter och hamnar sedan på deponi. Detta examensarbete har tillsammans med Industrial Development Center AB syftat till att skapa en mer hållbar industriell tillverkning inom Skaraborgsregionen, genom att forma en produktutvecklingsprocess i enlighet med cirkulär ekonomi. Cirkulär ekonomi förespråkar att avfall inte får förekomma och att produkter och material ska cirkulera i kretslopp. Projektet bestod därför av en bred förstudie för att samla och utvärdera ett stort område med teorier, processer och företagens ansvarsroller. Vidare analyserades en generell produkts livscykel och en processkarta skapades tillsammans med cirkulär ekonomi och produktutvecklingsprocesser. Arbetet knöts an med en omfattande kravspecifikation som sedan användes som utvärderingsunderlag för vad som skulle bli en ny produktutvecklingsprocess med cirkulär ekonomi implementerat. Slutligen utvärderades resultatet med en erfaren användare för att få en initial bedömning av resultatets användbarhet för målgrupperna. Resultatet blev en miljöanpassad produktutvecklingsprocess och en folder beskrivande hur och varför cirkulär ekonomi kan gynna företag och samhälle. / Today’s trend of production and consumption has a linear type. Material is extracted, become products and then end up as landfill. This thesis has together with Industrial Development Center AB aimed to create a more sustainable industrial production within the region of Skaraborg, by forming a product development process according to circular economy. Circular economy advocates that there should be no waste and products and material should circulate throughout different cycles. Hence this thesis consist of a broad pre-study to collect and evaluate a big range of theories, processes and enterprise responsibilities. Later on a general product lifecycle was studied and a map of a process was made with circular economy and product development processes in mind. The work was tied together by a performance specification table. This document was also used as a basis for the evaluation of the final product development process with circular economy implemented. Finally, the result was also evaluated by an experienced user to get an initial assessment of the result’s usability for the target groups. The result was an environmentally adapted product development process and a folder explaining how and why circular economy is to support enterprises and the community.
26

Power Estimation Tool for Digital Front-End 5G Radio ASIC

Bhutada, Rajnandini January 2023 (has links)
Application Specific Integrated Circuits (ASICs) are critical to delivering on 5G’s promises of high speed, low latency, and expanded capacity. Digital Front-End (DFE) ASICs are particularly important components because they enhance crucial signal processing activities. It handles duties including carrier mixing, up-sampling, and modulation-demodulation, allowing for efficient data transmission and reception inthe complicated 5G environment. The main aim of this work is to develop a power estimation tool for DFE radio ASICs and to understand the different use cases. It also studies the spread of power consumption, taking into account process and metal variations. The thesis provides a detailed case study of the DFE ASIC, including its Intellectual Property (IP) blocks, configurations, and protocols. It investigates the power consumption of DFE ASICs under various conditions, including active processing, power-saving mode, and no clock. In this thesis we build a power model that describes how the factors affect the ASIC’s power consumption. It also performs spread analysis to evaluate the impact of all factors using MATLAB tool. Based on this we then generate three distributionmodels to study the combined likelihood of the variations. It also uses Monte Carlo simulation to understand total power usage. Through this work we can conclude that the power consumption of DFE ASICs is affected by a variety of factors. The power model and spread analysis can be usedto forecast and optimize power usage in 5G systems.
27

Weight reduction of a connecting fitting used for frame assembly : A design optimization at IKEA Components AB / Viktreducering av ett beslag för rammontering : En designoptimering på IKEA Components AB

Sjöqvist, Emil, Johansson, David January 2019 (has links)
Continuous improvements are an integral part for the development of everyday life. These improvements do not only ascertain financial gain but also lessening the environmental impact. The purpose of this study is to gain a deeper understanding of the design process and the decisions required to achieve an optimal design with respect to weight reduction, while retaining the required strength. The study will also investigate the choice of material. This will be done through material and design studies, along with strength calculations of the product in question. The conclusion from this study is that it is possible to save a certain percentage of the material used, while keeping the strength, form, fit and function intact. The material study provided with a recommendation of the zinc alloy ZA-8. It is an alloy with a good combination of great strength, low density and price.
28

A 5Gb/s Speculative DFE for 2x Blind ADC-based Receivers in 65-nm CMOS

Sarvari, Siamak 16 September 2011 (has links)
This thesis proposes a decision-feedback equalizer (DFE) scheme for blind ADC-based receivers to overcome the challenges introduced by blind sampling. It presents the design, simulation, and implementation of a 5Gb/s speculative DFE for a 2x blind ADC-based receiver. The complete receiver, including the ADC, the DFE, and a 2x blind clock and data recovery (CDR) circuit, is implemented in Fujitsu’s 65-nm CMOS process. Measurements of the fabricated test-chip confirm 5Gb/s data recovery with bit error rate (BER) less than 1e−12 in the presence of a test channel introducing 13.3dB of attenuation at the Nyquist frequency of 2.5GHz. The receiver tolerates 0.24UIpp of high-frequency sinusoidal jitter (SJ) in this case. Without the DFE, the BER exceeds 1e−8 even when no SJ is applied.
29

A 5Gb/s Speculative DFE for 2x Blind ADC-based Receivers in 65-nm CMOS

Sarvari, Siamak 16 September 2011 (has links)
This thesis proposes a decision-feedback equalizer (DFE) scheme for blind ADC-based receivers to overcome the challenges introduced by blind sampling. It presents the design, simulation, and implementation of a 5Gb/s speculative DFE for a 2x blind ADC-based receiver. The complete receiver, including the ADC, the DFE, and a 2x blind clock and data recovery (CDR) circuit, is implemented in Fujitsu’s 65-nm CMOS process. Measurements of the fabricated test-chip confirm 5Gb/s data recovery with bit error rate (BER) less than 1e−12 in the presence of a test channel introducing 13.3dB of attenuation at the Nyquist frequency of 2.5GHz. The receiver tolerates 0.24UIpp of high-frequency sinusoidal jitter (SJ) in this case. Without the DFE, the BER exceeds 1e−8 even when no SJ is applied.
30

Schémas de décodage MIMO à Complexité Réduite

Salah, Abdellatif 12 July 2010 (has links) (PDF)
L'utilisation des antennes MIMO est une technique qui permet d'exploiter de façon très efficace la diversité spatiale et temporelle présente dans certains systèmes de communication, dont le canal sans fil. Le principal avantage de cette technique est une très grande efficacité spectrale. De nos jours, où le canal radio-mobile est de plus en plus utilisé pour transmettre tout type d'information, les méthodes permettant une utilisation plus efficace du spectre électromagnétique ont une importance fondamentale. Les algorithmes de réception connus aujourd'hui sont très complexes, même en ce qui concerne les systèmes MIMO avec les codes espace-temps les plus simples. Cette complexité reste l'un des obstacles principaux à l'exploitation réelle. Cette thèse présente une étude très détaillée de la complexité, la performance et les aspects les plus intéressants du comportement des algorithmes de la réception pour le décodage MIMO, étude qui présente un moyen rapide pour une éventuelle conception des architectures adaptées à ce problème. Parmi les sujets présentés dans cette thèse, une étude approfondie de la performance et la complexité de ces algorithmes a été réalisée, ayant pour objectif d'avoir une connaissance suffisante pour pouvoir choisir, parmi le grand nombre d'algorithmes connus, le mieux adapté à chaque système particulier. Des améliorations aux algorithmes connus ont aussi été proposées et analysées.

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