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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

Advancements in Radio Astronomical Array Processing: Digital Back End Development and Interferometric Array Interference Mitigation

Burnett, Mitchell Costus 01 December 2017 (has links)
The Brigham Young University (BYU) Radio Astronomy Systems group, in collaboration with the National Radio Astronomy Observatory (NRAO), the Center for Astrophysics at West Virginia University (WVU), and the Green Bank Observatory (GBO) have developed, and commissioned, a broadband real-time digital back end processing system for a 38-element phased array feed (PAF) with 150 MHz of instantaneous bandwidth. This system is capable of producing coarse and fine channel correlations, and implements a real-time beamformer that forms 7 simultaneous dual-polarized beams. This thesis outlines the hardware and software development for the digital back end and presents on-telescope commissioning results. This system has been measured to provide an unprecedented low Tsys/η noise level of 28 K and can perform maps of galactic hydrogen observations in a fraction of the time of a conventional single horn feed. The National Radio Astronomy Observatory (NRAO) has recently announced the concept and development of the next generation Very Large Array (ngVLA), a large interferometric array consisting of 300 radio telescopes and longest baseline (distance between a pair of antennas) of 300 km. Large interferometric arrays have been shown to attenuate radio frequency interference (RFI) because it is decorrelated as it propagates across long baselines. This is not always sufficient, especially with dense core array geometries and with the ever-increasing amount of strong RFI sources. Conventional RFI projection-based mitigation techniques have performed poorly on large interferometers because of covariance matrix estimation error due to decorrelation when identifying interference subspace parameters. This thesis presents an algorithm that overcomes the challenge of decorrelation by applying subspace projection via subarray processing (SP-SAP). Each subarray is designed to have a set of elements with high mutual correlation in the interferer for better estimation of subspace parameters. In simulation, compared to the former approach of applying subspace projection on the full array, SP-SAP improves mitigation of the RFI on the order of 9 dB. A signal of interest is shown then to be observable through the RFI in a full synthetic image.
22

Zadní část překladače podmnožiny jazyka C pro 8-bitový procesor / Compiler Back-End of Subset of Language C for 8-Bit Processor

Horník, Jakub January 2011 (has links)
A compiler allows us to describe an algorithm in a high-level programming language with a higher level of abstraction and readability than a low-level machine code. This work describes design of the compiler back-end of subset of language C for 8-bit soft-core microcontroller Xilinx PicoBlaze-3. Design is described from the initial selection of a suitable framework to the implementation itself. One of the main reasons of this work is that there is not any suitable compiler for this processor.
23

Serverový framework pro hromadné testování Android aplikací / Server Framework For Batch Android Applications Testing

Čtvrtníček, Dušan January 2015 (has links)
This master's thesis is dedicated to the remote control of Android devices using the Android Debug bridge tool. Another essential part of the work is automated batch testing of Android applications. It focuses on individual tools (Android Debug Bridge, MonkeyRunner, logcat, Appium) needed to resolve this issue. It also describes a web framework Nette and other technologies that were used for the final design and implementation of information system.
24

Process Window Challenges in Advanced Manufacturing: New Materials and Integration Solutions

Fox, Robert, Augur, Rod, Child, Craig, Zaleski, Mark 22 July 2016 (has links)
With the continued progression of Moore’s law into the sub-14nm technology nodes, interconnect RC and power dissipation scaling play an increasingly important role in overall product performance. As critical dimensions in the mainstream Cu/ULK interconnect system shrink below 30nm, corresponding increases in relative process variation and decreases in overall process window mandate increasingly complex integrated solutions. Traditional metallization processes, e.g. PVD barrier and seed layers, no longer scale for all layout configurations as they reach physical and geometric limitations. Interactions between design, OPC, and patterning also play more and more critical roles with respect to reliability and yield in volume manufacturing; stated simply, scaling is no longer “business as usual”. Restricted design layouts, prescriptive design rules, novel materials, and holistic integration solutions each therefore become necessary to maximize available process windows, thus enabling new generations of cost-competitive products in the marketplace.
25

Automation of Supply Processes : A Study at Ericsson AB

Pimenta de Almeida, Mariana January 2019 (has links)
In the Information and Communication Technology (ICT) industry, the pressure to accelerate the deployment of 5G technology has created a new competitive environment for businesses. This technology not only enables lower latency, but also higher number of connected devices, higher amounts of shared data, and faster. The growing demand from customers is pressuring every stage of the supply chain to become more efficient. In this industry, achieving a short time-tomarket is vital to stay ahead of competitors and position the company as a trend-setter in the eyes of customers. Therefore, it has become necessary to overall shorten lead times and deliver products in a faster way. This study was performed in collaboration with Ericsson AB, more specifically in the Ericsson Outbound Supply EMEA. Recent escalations from customers have shown that Ericsson’s ways of working to handle customer purchase orders are not being efficient. In many cases, it is taking longer to process the order than the lead times agreed on the contract with the customer. As a result, this study investigates how automation technologies can improve end-to-end order flows, how these can affect Ericsson as an organisation and its workforce, as well as which factors must be taken into consideration when implementing automation. In order to support the investigation, an analysis of the issues most frequently affecting hardware deliveries to customers was also conducted through the Spiderweb program. The latter is an internal improvement initiative of Ericsson Supply, focused on improving Ericsson’s order handling flows for the Market Area Europe and Latin America. The study was based on the following research questions: How can automation technologies help to improve Supply’s performance? How does automation impact the company as an organisation, its culture and workforce? How can the improvement methodology followed in the Spiderweb drive automation discoveries? Qualitative data was primarily collected through meetings with Spiderweb program drivers and 11 interviews held with different stakeholders at Ericsson Supply. Conclusively, this study indicates that the four critical factors that will require further developments for automation in Supply to become a reality are: its culture; the establishment of a data-driven organisation; the coordination of different processes and communication between dependent stakeholders; and the technical implementation of automation technology and other tools used locally. It is also concluded that the full potential of automation will only be realised if accompanied by a corresponding development of the workforce, and a clear communication of the strategy from top management. Lastly, the main recommendation to Supply regards the need to standardise order handling processes and simplify order flows, prior to any automation implementation in Supply. / Inom informations- och kommunikationsteknologinäringen (IKT) har trycket för att påskynda implementeringen av 5G-teknik skapat en ny konkurrensmiljö för företagen. Denna teknik möjliggör inte bara lägre latens, utan också större antal anslutna enheter, större mängder delad data och snabbare. Den växande efterfrågan från kunderna pressar varje steg i leveranskedjan att bli effektivare. I denna bransch är det viktigt att uppnå en kort tid till marknaden för att ligga före konkurrenterna och positionera företaget som trendmässigt i kunders ögon. Därför har det blivit nödvändigt att övergripande förkorta ledtiderna och leverera produkter på ett snabbare sätt. Denna studie utfördes i samarbete med Ericsson AB, mer specifikt i Ericsson Outbound Supply EMEA. Nya upptrappningar från kunder har visat att Ericssons sätt att arbeta för att hantera kundköporder inte är effektiva. I många fall tar det längre tid att behandla beställningen än de ledtider som avtalats med kunden. I denna studie undersöks hur automatiseringstekniker kan förbättra ordningsflödena från början till slut, hur dessa kan påverka Ericsson som organisation och dess arbetskraft, samt vilka faktorer som måste beaktas vid implementering av automatisering. För att stödja utredningen genomfördes också en analys av de problem som oftast påverkar hårdvaruleveranser till kunder genom Spiderweb-programmet. Det senare är ett internt förbättringsinitiativ från Ericsson Supply, fokuserat på att förbättra Ericssons orderhanteringsflöden för marknadsområdet Europa och Latinamerika. Studien baserades på följande forskningsfrågor: Hur kan automatiseringsteknologier bidra till att förbättra Supply’s prestanda? Hur påverkar automatisering företaget som organisation, dess kultur och arbetskraft? Hur kan förbättringsmetodiken följas i Spiderweb-enhetens automatiseringsupptäckter? Kvalitativ data samlades främst genom möten med Spiderwebprogramdrivare och 11 intervjuer med olika intressenter på Ericsson Supply. Sammanfattningsvis indikerar denna studie att de fyra kritiska faktorerna som kommer att kräva ytterligare utveckling för att automatisering i Supply ska bli verklighet är: dess kultur; inrättande av en datadriven organisation; samordning av olika processer och kommunikation mellan beroende intressenter; och teknisk implementering av automatiseringsteknologi och andra verktyg som används lokalt. Det dras också slutsatsen att automatiseringspotentialen fullt ut kommer att realiseras om den åtföljs av en motsvarande utveckling av arbetskraften och en tydlig kommunikation av strategin från toppledningen. Slutligen beaktar huvudrekommendationen till Supply behovet av att standardisera orderhanteringsprocesser och förenkla orderflöden innan automatiseringsimplementering i Supply startar.
26

Efficient Estimation for Small Multi-Rotor Air Vehicles Operating in Unknown, Indoor Environments

Macdonald, John Charles 07 December 2012 (has links) (PDF)
In this dissertation we present advances in developing an autonomous air vehicle capable of navigating through unknown, indoor environments. The problem imposes stringent limits on the computational power available onboard the vehicle, but the environment necessitates using 3D sensors such as stereo or RGB-D cameras whose data requires significant processing. We address the problem by proposing and developing key elements of a relative navigation scheme that moves as many processing tasks as possible out of the time-critical functions needed to maintain flight. We present in Chapter 2 analysis and results for an improved multirotor helicopter state estimator. The filter generates more accurate estimates by using an improved dynamic model for the vehicle and by properly accounting for the correlations that exist in the uncertainty during state propagation. As a result, the filter can rely more heavily on frequent and easy to process measurements from gyroscopes and accelerometers, making it more robust to error in the processing intensive information received from the exteroceptive sensors. In Chapter 3 we present BERT, a novel approach to map optimization. The goal of map optimization is to produce an accurate global map of the environment by refining the relative pose transformation estimates generated by the real-time navigation system. We develop BERT to jointly optimize the global poses and relative transformations. BERT exploits properties of independence and conditional independence to allow new information to efficiently flow through the network of transformations. We show that BERT achieves the same final solution as a leading iterative optimization algorithm. However, BERT delivers noticeably better intermediate results for the relative transformation estimates. The improved intermediate results, along with more readily available covariance estimates, make BERT especially applicable to our problem where computational resources are limited. We conclude in Chapter 4 with analysis and results that extend BERT beyond the simple example of Chapter 3. We identify important structure in the network of transformations and address challenges arising in more general map optimization problems. We demonstrate results from several variations of the algorithm and conclude the dissertation with a roadmap for future work.
27

Globally Consistent Map Generation in GPS-Degraded Environments

Nyholm, Paul William 01 May 2015 (has links) (PDF)
Heavy reliance on GPS is preventing unmanned air systems (UAS) from being fully inte- grated for many of their numerous applications. In the absence of GPS, GPS-reliant UAS have difficulty estimating vehicle states resulting in vehicle failures. Additionally, naively using erro- neous measurements when GPS is available can result in significant state inaccuracies. We present a simultaneous localization and mapping (SLAM) solution to GPS-degraded navigation that al- lows vehicle state estimation and control independent of global information. Optionally, a global map can be constructed from odometry measurements and can be updated with GPS measurements while maintaining robustness against outliers.We detail a relative navigation SLAM framework that distinguishes a relative front end and global back end. It decouples the front-end flight critical processes, such as state estimation and control, from back-end global map construction and optimization. Components of the front end function relative to a locally-established coordinate frame, completely independent from global state information. The approach maintains state estimation continuity in the absence of GPS mea- surements or when there are jumps in the global state, such as after map optimization. A global graph-based SLAM back end complements the relative front end by constructing and refining a global map using odometry measurements provided by the front end.Unlike typical approaches that use GPS in the front end to estimate global states, our unique back end uses a virtual zero and virtual constraint to allow intermittent GPS measurements to be applied directly to the map. Methods are presented to reduce the scale of GPS induced costs and refine the map’s initial orientation prior to optimization, both of which facilitate convergence to a globally consistent map. The approach uses a state-of-the-art robust least-squares optimization algorithm called dynamic covariance scaling (DCS) to identify and reject outlying GPS measure- ments and loop closures. We demonstrate our system’s ability to generate globally consistent and aligned maps in GPS-degraded environments through simulation, hand-carried, and flight test re- sults.
28

Les Procédés par Plasmas Impliqués dans l'Intégration des Matériaux SiOCH Poreux pour les Interconnexions en Microélectronique

Darnon, Maxime 23 October 2007 (has links) (PDF)
Pour réduire la taille des dispositifs et les temps de commutation en microélectronique, les lignes d'interconnexions doivent être isolées par du SiOCH poreux. Cependant, la réalisation de tranchées étroites dans le SiOCH poreux nécessite de revoir les différents procédés par plasmas (gravure, traitements post-gravure) et les schémas d'intégration, puisque ce matériau est facilement dégradé lorsqu'il est exposé à un plasma.<br /><br />Cette thèse porte sur les interactions plasmas/matériaux pour l'intégration des SiOCH poreux dans des tranchées très étroites (<100 nm). Les diagnostics des plasmas et l'analyse des matériaux exposés aux plasmas permettent de caractériser et d'optimiser les procédés de transfert de motifs d'un masque métallique ou organique dans un SiOCH poreux ou hybride (rendu poreux en fin d'intégration). La modification des matériaux poreux et hybrides par les plasmas post-gravure est également étudiée.<br /><br />Avec un plasma fluorocarboné, le matériau hybride présente des mécanismes de gravure similaires à ceux d'un SiOCH dense. Le TiN et le matériau organique ont des mécanismes de gravure différents de ceux des diélectriques, ce qui assure une bonne sélectivité. Le procédé de gravure optimisé pour le masque organique permet la gravure de tranchées très étroites avec un profil quasiment vertical. Par contre, le contrôle dimensionnel de tranchées étroites est plus difficile avec un masque en TiN, en raison de dépôts métalliques sur les flancs, de profils en forme de tonneaux, et du flambage des lignes. Après l'étape de gravure, les matériaux poreux et hybrides sont modifiés par les plasmas post-gravure.
29

Βελτιστοποίηση και αυτοματοποίηση τεχνικών μεταγλώττισης μέσω μοντελοποίησης σε επαναπροσδιοριζόμενα συστήματα / Compiler optimization techniques for reconfigurable systems

Δημητρουλάκος, Γρηγόρης 24 October 2007 (has links)
Το αντικείμενο που πραγματεύεται η παρούσα διδακτορική διατριβή σχετίζεται με την ανάπτυξη βελτιστοποιητικών τεχνικών μεταγλώττισης για επαναπροσδιοριζόμενα ολοκληρωμένα συστήματα γενικού και ειδικού σκοπού. Στόχος είναι η βελτιστοποίηση της εκτέλεσης των εφαρμογών ως προς την ταχύτητα, την επιφάνεια ολοκλήρωσης και την κατανάλωση ισχύος. Αυτό επιτυγχάνεται με την εισαγωγή πρωτότυπων τεχνικών μεταγλώττισης αλλά και από την ανεύρεση βέλτιστων αρχιτεκτονικών. Η αυτοματοποίηση των μεθοδολογιών επιτυγχάνεται με την ανάπτυξη εργαλείων βελτιστοποίησης που υλοποιούν την μεθοδολογία μεταγλώττισης. Τα πειράματα έδειξαν γρήγορο προσδιορισμό βέλτιστων λύσεων και σημαντικές βελτιώσεις στην ταχύτητα, επιφάνεια ολοκλήρωσης και κατανάλωση ισχύος για μια σειρά από εφαρμογές ψηφιακής επεξεργασίας σήματος. / The research material that is presented in this PhD Phesis is related with developement of compilation techniques for reconfigurable systems and application specific integrated circuits. The objective is the optimization of the execution of the applications in terms of speed area and power consumption in these architectures. This is achieved by developing original compiling techniques and efficient architecture instances. Moreover, one of the fundamental objectives of this thesis is the automation of these techniques for fast solution determination. Experiments showed that applications are executed faster while keeping the area and power overhead low. The experiments are based on a set of Digital Signal Processing applications.
30

Electron microscopic studies of low-k inter-metal dielectrics

Singh, Pradeep Kumar 26 September 2014 (has links) (PDF)
Die fortwährende Verkleinerung der Strukturbreiten in der Mikroelektronik erfordert es, herkömmliche SiO2 Dielektrika durch Materialien mit kleinerer Dielektrizitätskonstante zu ersetzen. Dafür sind verschiedene „low-k Materialien“ entwickelt worden. Unter diesen sind die Organosilikatgläser, die aus SiO2 Netzwerken mit eingelagerten Methylgruppen bestehen wegen ihrer ausgezeichneten Eigenschaften besonders interessant als Dielektrika zwischen metallischen Leiterbahnen. In dieser Arbeit sind fünf verschiedene dieser „low-k Materialien“ untersucht worden: ein dichtes und vier poröse Materialien, die alle durch plasmagestützte chemische Gasphasenabscheidung hergestellt wurden. Die strukturellen, chemischen und dielektrischen Eigenschaften der Materialien wurden mit Hilfe der analytischen Durchstrahlungselektronenmikroskopie unter Verwendung eines abbildenden GATAN-Energiespektrometers untersucht. Die Bestimmung der radialen Verteilungsfunktion (RDF) zur Charakterisierung der atomaren Nahordnung ermöglicht uns die Ermittlung mittlerer Bindungslängen und – winkel sowie der mikroskopischen Dichte des Materials. Gegenüber SiO2 wurden in den untersuchten „low-k Materialien“ stark veränderte mittlere Si-O, O-O und Si-Si Bindungslängen gefunden. Dieses wirkt sich natürlich auch auf die mittleren Si-O-Si bzw. O-Si-O Bindungswinkel aus, und wie erwartet war auch die mikroskopische Dichte der „low-k Materialien“ kleiner als die Dichte des SiO2. Elektronen Energieverlustspektroskopie (EELS) und Photoelektronenspektroskopie (XPS) wurden zur Charakterisierung der chemischen Umgebung der Atome in den „low-k Materialien“ herangezogen. Die Energien von Ionisationskanten und die Bindungsenergien der Silizium-2p und Sauerstoff-1s Elektronen waren in den „low-k Materialien“ größer als im SiO2. Die Kohlenstoffatome kamen in den „low-k Materialien“ sowohl sp2 als auch sp3 hybridisiert vor. sp2-Hybridisierung liegt vor, wenn Bindungen wie Si=CH2 und C=C im Netzwerk vorkommen, während sp3 Hybridisierung z.B. dann vorkommt, wenn freie Si-Bindungen durch –CH3 Gruppen abgesättigt werden. Die Anteile an sp2- bzw. sp3-hybridisierten Kohlenstoffatome wurden aus der Feinstruktur der K-Energieverlustkanten des Kohlenstoffs abgeschätzt. Das ergab, daß die meisten Kohlenstoffatome in den „low-k Materialien“ sp2-hybridisiert sind. Die dielektrischen Eigenschaften wurden durch Kramers-Kronig-Transformation einer Energieverlustfunktion ermittelt, die aus dem Niedrigverlust-EELS-Spektrum im Bereich der Plasmonenanregungen gewonnen wurde. Die Bandlücke des SiO2 beträgt ungefähr 9 eV während dichte „low-k Materialien“ aufgrund der Unregelmäßigkeiten in ihrem SiO2-Netzwerk zusätzliche Zustandsdichten innerhalb der Bandlücke aufweisen. Die Erzeugung von Poren im „low-k Material“ vermindert offenbar die Zustandsdichte im Bereich der Bandlücke und erweitert diese im Vergleich zum SiO2. Eine Modellrechnung mit der Dichtefunktionaltheorie für ein Strukturmodell, das den „low-k Materialien“ nahe kommt, ist zum Vergleich mit der experimentell gefundenen kombinierten Zustandsdichte herangezogen worden und zeigt eine gute Übereinstimmung. Die im Standard-Herstellungsprozeß vorkommenden Verfahren des Plasmaätzens und der Plasmaveraschung können die Struktur des „low-k Materials“ z.B. an den Seitenwänden von Ätzgräben verändern. Die gestörten Bereiche wurden mit der energiegefilterten Elektronenmikroskopie untersucht. Dabei wurde gefunden, daß sich die Strukturveränderungen der Seitenwände bis zu einer Tiefe in der Größenordnung von ungefähr 10 Nanometern erstrecken. Diese Bereiche sind verarmt an Kohlenstoff und ähneln folglich mehr einem SiO2-Dielektrikum. Die Kohlenstoffverarmung erstreckt sich in die „low-k Schicht“ in Form eines gaussartigen Profils mit maximaler Kohlenstoffkonzentration in der Mitte der Schicht. Die Sauerstoffkonzentration und die mikroskopische Dichte steigen in der Nähe der Seitenwände.

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