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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.
91

Error Locating Arrays, Adaptive Software Testing, and Combinatorial Group Testing

Chodoriwsky, Jacob N. January 2012 (has links)
Combinatorial Group Testing (CGT) is a process of identifying faulty interactions (“errors”) within a particular set of items. Error Locating Arrays (ELAs) are combinatorial designs that can be built from Covering Arrays (CAs) to not only cover all errors in a system (each involving up to a certain number of items), but to locate and identify the errors as well. In this thesis, we survey known results for CGT, as well as CAs, ELAs, and some other types of related arrays. More importantly, we give several new results. First, we give a new algorithm that can be used to test a system in which each component (factor) has two options (values), and at most two errors are present. We show that, for systems with at most two errors, our algorithm improves upon a related algorithm by Mart´ınez et al. in terms of both robustness and efficiency. Second, we give the first adaptive CGT algorithm that can identify, among a given set of k items, all faulty interactions involving up to three items. We then compare it, performance-wise, to current-best nonadaptive method that can identify faulty interactions involving up to three items. We also give the first adaptive ELA-building algorithm that can identify all faulty interactions involving up to three items when safe values are known. Both of our new algorithms are generalizations of ones previously given by Mart´ınez et al. for identifying all faulty interactions involving up to two items.
92

Detekce a počítání automobilů v obraze (videodetekce) / Videodetection - traffic monitoring

Kozina, Lubomír January 2010 (has links)
In this master’s thesis on the topic Videodetection - traffic monitoring I was engaged in searching moving objects in traffic images sequence. There are described various methods background model computation and moving vehicles marking, counting or velocity calculating in the thesis. It was created a graphical user interface for traffic scene evaluation in MATLAB.
93

Experimentální analýza proudu vzduchu z ofukovače osobního vozu s využitím žárového anemometru a návrh hodnocení kvality ofukovače / Experimental analysis of automobile ventilating outlet air flow using hot wire anemometry and draft of outlet quality rating

Ležovič, Tomáš January 2011 (has links)
The master’s thesis deals with air flow in the interior of automobile Škoda Octavia. The attention is focused only at a side ventilating outlet. Author’s effort was to propose the appropriate criteria for evaluation and assessment of ventilating outlet quality and elaborate the methodology of measurement for these criteria. Then follows the application of the methodology and measurement of velocity field of air flow from the outlet by the method of hot wire anemometry. The thesis also contains comparison of the results with the results attained by the smoke visualization.
94

Lidar-based SLAM : Investigation of environmental changes and use of road-edges for improved positioning

Karlsson, Oskar January 2020 (has links)
The ability to position yourself and map the surroundings is an important aspect for both civilian and military applications. Global navigation satellite systems are very popular and are widely used for positioning. This kind of system is however quite easy to disturb and therefore lacks robustness. The introduction of autonomous vehicles has accelerated the development of local positioning systems. This thesis work is done in collaboration with FOI in Linköping, using a positioning system with LIDAR and IMU sensors in a EKF-SLAM system using the GTSAM framework. The goal was to evaluate the system in different conditions and also investigate the possibility of using the road surface for positioning. Data available at FOI was used for evaluation. These data sets have a known sensor setup and matches the intended hardware. The data sets used have been gathered on three different occasions in a residential area, a country road and a forest road in sunny spring weather on two occasions and one occasion in winter conditions. To evaluate the performance several different measures were used, common ones such as looking at positioning error and RMSE, but also the number of found landmarks, the estimated distance between landmarks and the drift of the vehicle. All results pointed towards the forest road providing the best positioning, the country road the worst and the residential area in between. When comparing different weather conditions the data set from winter conditions performed the best. The difference between the two spring data sets was quite different which indicates that there may be other factors at play than just weather. A road edge detector was implemented to improve mapping and positioning. Vectors, denoted road vectors, with position and orientation were adapted to the edge points and the change between these road vectors were used in the system using GTSAM in areas with few landmarks. The clearest improvements to the drift in the vehicle direction was in the longer country area where the error was lowered with 6.4 % with increase in the error sideways and in orientation as side effects. The implemented method has a significant impact on the computational cost of the system as well as requiring precise adjustment of uncertainty to have a noticeable improvement and not worsen the overall results.
95

Realization and comparison of various mesh refinement strategies near edges

Apel, T., Milde, F. 30 October 1998 (has links)
This paper is concerned with mesh refinement techniques for treating elliptic boundary value problems in domains with re- entrant edges and corners, and focuses on numerical experiments. After a section about the model problem and discretization strategies, their realization in the experimental code FEMPS3D is described. For two representative examples the numerically determined error norms are recorded, and various mesh refinement strategies are compared.
96

XIV. Internationales Oberflächenkolloquium: 30.01.-01.02.2017 an der Technischen Universität Chemnitz; Tagungsband

Gröger, Sophie, Weißgerber, Marco January 2017 (has links)
Zentrales Thema des Oberflächenkolloquiums 2017 ist die anwendungsorientierte, funktionale geometrische Spezifikation und Messung der Oberfläche im Sinne der Gesamtgeometrie. Neben der Mikrogestalt wird dabei das Zusammenwirken mit der Makrogeometrie zur Erfüllung funktionaler Anforderungen diskutiert. Interessante Beiträge aus Industrie und Wissenschaft zeigen sowohl Lösungen als auch Probleme verschiedenster Fachbereiche auf. / Key issue of the International Colloquium on Surfaces 2017 is the application‐oriented, functional geometrical specification and verification of surfaces as part of the entire geometry. Therefore we discuss the interaction of micro and macro geometry, to fulfill functional requirements. Interesting articles from industry and research point out solutions as well as problems from multifaceted fields of expertise.
97

Detecting and comparing Kanban boards using Computer Vision / Detektering och jämförelse av Kanbantavlor med hjälp av datorseende

Behnam, Humam January 2022 (has links)
This thesis investigates the problem of detecting and tracking sticky notes on Kanban boards using classical computer vision techniques. Currently, there exists some alternatives for digitizing sticky notes, but none keep track of notes that have already been digitized, allowing for duplicate notes to be created when scanning multiple images of the same Kanban board. Kanban boards are widely used in various industries, and being able to recognize, and possibly in the future even digitize entire Kanban boards could provide users with extended functionality. The implementation presented in this thesis is able to, given two images, detect the Kanban boards in each image and rectify them. The rectified images are then sent to the Google Cloud Vision API for text detection. Then, the rectified images are used to detect all the sticky notes. The positional information of the notes and columns of the Kanban boards are then used to filter the text detection to find the text inside each note as well as the header text for each column. Between the two images, the columns are compared and matched, as well as notes of the same color. If columns or notes in one image do not have a match in the second image, it is concluded that the boards are different, and the user is informed of why. If all columns and notes in one image have matches in the second image but some notes have moved, the user is informed of which notes that have moved, and how they have moved as well. The different experiments conducted in this thesis on the implementation show that it works well, but it is very confined to strict requirements, making it unsuitable for commercial use. The biggest problem to solve is to make the implementation more general, i.e. the Kanban board layout, sticky note shapes and colors as well as their actual content. / Denna avhandling undersöker problemet med att upptäcka och spåra klisterlappar och Kanban-tavlor med hjälp av klassiska datorseendetekniker. För närvarande finns det några alternativ för att digitalisera klisterlappar, men ingen håller reda på anteckningar som redan har digitaliserats, vilket gör att duplicerade anteckningar kan skapas när du skannar flera bilder av samma Kanban-kort. Kanban-kort används flitigt i olika branscher och att kunna känna igen, och eventuellt i framtiden även digitalisera hela Kanban-tavlor, skulle kunna ge användarna utökad funktionalitet. Implementeringen som presenteras i denna avhandling kan, givet två bilder, upptäcka Kanban-brädorna i varje bild och korrigera dem. De korrigerade bilderna skickas sedan till Google Cloud Vision API för textidentifiering. Sedan används de korrigerade bilderna för att upptäcka alla klisterlappar. Positionsinformationen för anteckningarna och kolumnerna på Kanban-tavlan används sedan för att filtrera textdetekteringen för att hitta texten i varje anteckning såväl som rubriktexten för varje kolumn. Mellan de två bilderna jämförs och matchas kolumnerna, samt anteckningar av samma färg. Om kolumner eller anteckningar i en bild inte har en matchning i den andra bilden dras slutsatsen att brädorna är olika och användaren informeras om varför. Om alla kolumner och anteckningar i en bild har matchningar i den andra bilden men några anteckningar har flyttats, informeras användaren om vilka anteckningar som har flyttats och hur de har flyttats. De olika experiment som genomförs i denna avhandling om implementering visar att den fungerar bra, men den är mycket begränsad till strikta krav, vilket gör den olämplig för kommersiellt bruk. Det största problemet att lösa är att göra implementeringen mer generell, d.v.s. Kanban-tavlans layout, klisterlapparnas former och färger samt deras faktiska innehåll.
98

Einfluss des Schleifprozesses auf die Kantenfestigkeit von thermisch entspanntem Floatglas

Bukieda, Paulina 04 March 2024 (has links)
Im Bauwesen kommen verschiedene Kantenausführungsarten von Glas zum Einsatz. In Abhängigkeit ihrer Art erfüllen sie Anforderungen an den Schnittschutz, die Maßhaltigkeit und die Ästhetik. Nach DIN 1249-11 erfolgt die Einteilung entsprechend des äußeren Erscheinungsbildes in geschnittene (KG), gesäumte (KGS), maßgeschliffene (KMG), geschliffene (KGN) und polierte (KPO) Kanten. Die mechanische Festigkeit der Glaskante ist jedoch gesondert zu betrachten. Die charakteristische Biegezugfestigkeit von Glas ist maßgeblich von dessen Oberflächenzustand abhängig. Die Herstellung und Bearbeitung der Kante erfolgt durch einen Materialeingriff mit harten Schneid- und Schleifwerkzeugen. Dabei werden die Oberflächenbeschaffenheit verändert und das Bruchverhalten beeinflusst. Bisher regelt die europäische Normung Kantenfestigkeiten in der Bemessung in Form von Beiwerten, welche die charakteristische Biegezugfestigkeit pauschal oder in Abhängigkeit der Kantenausführungsart abmindern. Bestehende Untersuchungen zeigen jedoch wesentliche Unterschiede der Kantenfestigkeit in Abhängigkeit von Kantenausführungsart und Herstellungsprozess. Die Bemessungswerte der Kantenfestigkeit gelten als untere Grenze der auf dem Markt verfügbaren Qualitäten. Wissenschaftlich belegte Beurteilungen der visuellen Kantenqualität mit Einschätzung ihrer mechanischen Festigkeit liegen bisher nur für die geschnittene Kantenausführung vor. Für den industriellen Schneidprozess wurden auf Basis systematischer Untersuchungen Parameter detektiert, die sich positiv auf die Kantenfestigkeit auswirken. Es ist unbekannt, wie sich der Oberflächeneingriff durch Schleif- und Polierprozesse auf die mechanische Festigkeit der dabei hergestellten Kantenausführungsarten auswirkt und welche Ursachen dafür zu benennen sind. Zudem fehlen geregelte, einheitliche Methoden, um die Kantenqualitäten optisch und mechanisch zu erfassen. Im Rahmen dieser Arbeit wird eine Versuchsmethodik entwickelt, welche über mikroskopische Analysen und Bruchversuche die Erfassung vergleichbarer optischer und mechanischer Kennwerte ermöglicht. In einer Zusammenführung der Methoden erfolgt erstmalig die Charakterisierung bruchverursachender Fehlstellen und deren Rückführung auf den Entstehungsort im Herstellungsprozess. Anhand einer systematischen Untersuchung verschiedener Kantenausführungsarten eines Herstellers findet die Erprobung und Bewertung der entwickelten Versuchsmethodik statt. Anschließend werden Prozessanpassungen zur Fehlstellenreduzierung vorgenommen und in Bezug auf eine Steigerung der Kantenfestigkeit untersucht. Weitere Analysen des Herstellungsprozesses eines zweiten Herstellers erfolgen für verschieden polierte Kanten. Entsprechend der ermittelten bruchverursachenden Fehlstellen werden Hypothesen für zukünftige Untersuchungen abgeleitet. Die Erkenntnisse dieser Arbeit stellen die wissenschaftliche Grundlage für verfahrenstechnische Handlungsempfehlungen zur Herstellung von Glaskanten dar. Der aktuelle Stand bedeutender europäischer Bemessungsregeln wird für abschließende normative Empfehlungen einbezogen. Die gesäumte Kante ergibt sich beim ersten Hersteller als Kantenausführungsart mit der höchsten Kantenfestigkeit. Für die maßgeschliffene, geschliffene und polierte Kante ergeben sich im Vergleich zur geschnittenen und gesäumten Kante geringere Festigkeiten. Die Untersuchung der polierten Kantenausführung des zweiten Herstellers ergibt, verglichen mit der polierten Kante des ersten Herstellers, eine höhere Kantenfestigkeit. Daraus leitet sich der Einfluss der Maschinenkonfiguration als einflussreicher Prozessparameter ab. Die Analyse der bruchverursachenden Fehlstellen zeigt, dass höherfeste Kanten mit einer Reduzierung von mikroskopisch erfassbaren Fehlstellen für die geschnittene, gesäumte und polierte Kante korrelieren. Darüber hinaus gewährleisten die in dieser Arbeit entwickelten Fehlstellenanalysen eine Detektion festigkeitsmindernder Fehlstellen, die auf eine Einbringung nach der Herstellung hindeuten und somit die Notwendigkeit von Kantenschutzmaßnahmen nach sich ziehen. Definitionen allgemeingültiger Prozessparameter in Schleif- und Polierprozessen, die eine positive Auswirkung auf die Kantenfestigkeit bearbeiteter Kanten haben, sind bisher in der Literatur nicht vorhanden. Die in dieser Arbeit beschriebenen Ergebnisse dienen als Grundlage zur Optimierung der Prozessparameter für hohe Kantenfestigkeiten. Experimentelle Nachweise der mechanischen Festigkeit sind dabei unabdingbar. Die Kantenqualität ist in optische und mechanische Eigenschaften zu unterscheiden. Die optisch als am hochwertigsten geltende polierte Kante geht nicht zwangsläufig mit einer hohen Kantenfestigkeit einher, was eine in der Praxis weitverbreitete Annahme widerlegt. In diesem Kontext leistet die vorliegende Arbeit einen Beitrag zum Verständnis der Herstellungsprozesse und der Bemessung von Glasbauteilen, um den steigenden Anforderungen im konstruktiven Glasbau gerecht zu werden.:1 Einleitung 2 Grundlagen zu Glaskanten 3 Wissensstand zur Kantenfestigkeit 4 Entwicklung einer Versuchsmethodik zur Erfassung der Kantenqualität 5 Systematische Analyse der Kantenqualität eines Herstellers 6 Einfluss von Prozessparametern auf die Kantenfestigkeit nach Kantenausführungsart 7 Diskussion der Ergebnisse 8 Bemessungsansätze für Glaskanten 9 Handlungsempfehlungen 10 Zusammenfassung und Ausblick 11 Literatur / In the building industry, different types of glass edges are used. Depending on their type, they fulfil requirements for cutting protection, dimensional accuracy, and aesthetics. According to DIN 1249-11, the classification is based on the visual appearance and includes cut (KG), arrissed (KGS), ground (KMG), smooth ground (KGN), and polished (KPO) edge finishing type. However, the mechanical strength of the glass edge requires additional consideration. The characteristic bending tensile strength of glass depends mostly on its surface condition. During production and processing the edge comes in contact with hard tools, which modifies the optical appearance and influences the strength. Presently, the European standardization regulates the edge strength in the design by general coefficients, which reduce the characteristic bending tensile strength depending on the edge finishing type. Existing studies show a large range of values in edge strength depending on the edge finishing and the manufacturer. The design edge strength considers the lower limits of the available glass edge finishing types. Scientifically based evaluation of the optical edge quality with assessment of the mechanical strength is available only for the cut edge. For the industrial cutting process, parameters have been determined on the basis of systematic investigations that show a positive influence on edge strength. It is still unknown how surface interferences by grinding and polishing processes affect the edge strength of processed glass edges and what are the underlying mechanisms. In addition, there is a lack of unified methods for assessing the mechanical edge quality. Within the scope of this work, a test methodology is developed that enables the determination of comparable optical and mechanical characteristics by means of microscopic analysis and destructive tests. A combination of different methods is used to characterize fracture-causing defects and to identify the location of their creation in the manufacturing process. The testing methods are approved and evaluated on the basis of a systematic examination of different edge types of one manufacturer. Subsequently, process adjustments for defect reduction are conducted and investigated with regard to an increase in edge strength. Moreover, the manufacturing process of various polished edge types of a second manufacturer are examined. Thereby, fracture-causing flaws are identified and hypotheses for future investigations are derived that form the basis for processing recommendations for the manufacturing of glass edges. The current status of relevant European design rules is finally discussed for normative recommendations. The arrised edge finishing type revealed the highest edge strength. For the ground, smooth ground, and polished edges, the edge strength is lower compared to the cut and arrised edges. The examination of the polished edge from the second manufacturer resulted in a higher edge strength compared to the polished edge from the first manufacturer. Therefore, the influence of the machine configuration is derived as an impacting process parameter. The analysis of fracturecausing defects has confirmed that a higher edge strength correlates with a reduction in microscopically detectable defects for the cut, arrised, and polished edge types. The defect analysis also enables the detection of strength-reducing defects that are introduced after production and require edge protection measures. Definitions of generally valid process parameters in grinding and polishing that positively affect the edge strength of machined edges are unknown. However, the results of this work enable manufacturers to optimize processes specific to their (manufacturing) process in order to ensure high values of edge strength. Nonetheless, experimental verifications are indispensable in this respect. Optical and mechanical properties of glass edges need to be considered separately. For example, the polished edge is considered to offer the highest optical quality. However, contrary to a widespread assumption, it does not necessarily display high edge strength. A better understanding of the manufacturing processes and the verification of edge strength are necessary for the design to meet the increasing demands in structural glass applications.:1 Einleitung 2 Grundlagen zu Glaskanten 3 Wissensstand zur Kantenfestigkeit 4 Entwicklung einer Versuchsmethodik zur Erfassung der Kantenqualität 5 Systematische Analyse der Kantenqualität eines Herstellers 6 Einfluss von Prozessparametern auf die Kantenfestigkeit nach Kantenausführungsart 7 Diskussion der Ergebnisse 8 Bemessungsansätze für Glaskanten 9 Handlungsempfehlungen 10 Zusammenfassung und Ausblick 11 Literatur
99

Voronoi tessellation quality: applications in digital image analysis

A-iyeh, Enoch January 1900 (has links)
A measure of the quality of Voronoi tessellations resulting from various mesh generators founded on feature-driven models is introduced in this work. A planar tessellation covers an image with polygons of various shapes and sizes. Tessellations have potential utility due to their geometry and the opportunity to derive useful information from them for object recognition, image processing and classification. Problem domains including images are generally feature-endowed, non-random domains. Generators modeled otherwise may easily guarantee quality of meshes but certainly bear no reference to features of the meshed problem domain. They are therefore unsuitable in point pattern identification, characterization and subsequently the study of meshed regions. We therefore found generators on features of the problem domain. This provides a basis for element quality studies and improvement based on quality criteria. The resulting polygonal meshes tessellating an n-dimensional digital image into convex regions are of varying element qualities. Given several types of mesh generating sets, a measure of overall solution quality is introduced to determine their effectiveness. Given a tessellation of general and mixed shapes, this presents a challenge in quality improvement. The Centroidal Voronoi Tessellation (CVT) technique is developed for quality improvement and guarantees of mixed, general-shaped elements and to preserve the validity of the tessellations. Mesh quality indicators and entropies introduced are useful for pattern studies, analysis, recognition and assessing information. Computed features of tessellated spaces are explored for image information content assessment and cell processing to expose detail using information theoretic methods. Tessellated spaces also furnish information on pattern structure and organization through their quality distributions. Mathematical and theoretical results obtained from these spaces help in understanding Voronoi diagrams as well as for their successful applications. Voronoi diagrams expose neighbourhood relations between pattern units. Given this realization, the foundation of near sets is developed for further applications. / February 2017
100

Predlog nove mere za ocenu kvaliteta slike prilikom interpolacije i njena implementacija u računarskoj obradi signal slike / The proposal of new measures for assessing the picture quality when interpolation and its implementation in the computer processing of the image signal

Maksimović-Moićević Sanja 21 October 2015 (has links)
<p>Osnovni doprinos ove doktorske disertacije je razvoj algortima i sistema za objektivnu procenu vizuelnog kvaliteta slike uzimajući u obzir najvažnija moguća oštećenja kao što su zamućenje ivica (oštrina) i poremećaj prirodnog izgleda teksture objekata na slici sa jedne strane i uticaj sadržaja slike (procenta ivica u slici) na procenu kvaliteta sa druge strane. Dakle, hipoteza izneta u ovom radu je da je potreban multiparametarski pristup da bi se dobila objektivna procena kvaliteta slike koja je što približnija subjektivnoj proceni.</p>

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