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Dissertationen zum Thema „Screen machine“
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1
Blowers, Andrew. „Detection of faults on rotary screen printed fabrics using machine vision“. Thesis, De Montfort University, 1995. http://hdl.handle.net/2086/4914.
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A project was sponsored by the SERC for research into the design of a colour vision system for the detection of print faults in rotary screen printed fabrics. The research was carried out at De Montfort University (formerly named Leicester Polytechnic), which has previous experience with Image Processing in relation to Textiles. The proposed system was required to identify, process and correct the common print faults which can occur during rotary screen printing. These can be divided into two main categories, systematic and random faults. This thesis covers the work undertakeni n the developmento f a laboratory-basedin spection systema ndt he subsequendte velopmenat nd testingo f methodologiesto facilitate factory-based on-line inspection. Initial investigation identified the requirement for colour segmentation algorithmsa ndt he researchin to anda nalysiso f suitablem ethodologiesf or segmentationf orms a fundamental part of this thesis. Important, new colour segmentation algorithms were developed from first principles by the author. These new methods offer improvements (in most cases significant) over the current `state-of-the-art' colour segmentation technology, and are applicable to a wide-range of computer vision tasks. These proposed methodologies have been rigorously tested and the findings of the investigation are presented as part of this thesis.
2
Pacherazova, Milena. „Keep your screen happy: Improving the usability of screen time tracking apps“. Thesis, Umeå universitet, Institutionen för informatik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-164232.
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The adoption of technology in our daily activities increased the time that we spend in front of the screen and changed the way we communicate and work. In recent years, many big companies started to develop and implement screen time management tools in their products to educate the user on how to improve their digital health. Those tools are an important step in the process, they bring awareness and help the users to change their habits. Several studies have focused on screen time tracking apps but not from the design perspective. Therefore, this thesis aims to explore the design of screen time management apps by developing two prototypes, which were used to evaluate different design elements and features. The results of this thesis present a guideline on how to improve the design of the existing screen time tracking tools and what additional features could be added to fulfil their aim and encourage users to change their behaviour.
3
Shapiro, Daniel. „Composing Recommendations Using Computer Screen Images: A Deep Learning Recommender System for PC Users“. Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36272.
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A new way to train a virtual assistant with unsupervised learning is presented in this thesis. Rather than integrating with a particular set of programs and interfaces, this new approach involves shallow integration between the virtual assistant and computer through machine vision. In effect the assistant interprets the computer screen in order to produce helpful recommendations to assist the computer user. In developing this new approach, called AVRA, the following methods are described: an unsupervised learning algorithm which enables the system to watch and learn from user behavior, a method for fast filtering of the text displayed on the computer screen, a deep learning classifier used to recognize key onscreen text in the presence of OCR translation errors, and a recommendation filtering algorithm to triage the many possible action recommendations. AVRA is compared to a similar commercial state-of-the-art system, to highlight how this work adds to the state of the art.
AVRA is a deep learning image processing and recommender system that can col- laborate with the computer user to accomplish various tasks. This document presents a comprehensive overview of the development and possible applications of this novel vir- tual assistant technology. It detects onscreen tasks based upon the context it perceives by analyzing successive computer screen images with neural networks. AVRA is a rec- ommender system, as it assists the user by producing action recommendations regarding onscreen tasks. In order to simplify the interaction between the user and AVRA, the system was designed to only produce action recommendations that can be accepted with a single mouse click. These action recommendations are produced without integration into each individual application executing on the computer. Furthermore, the action recommendations are personalized to the user’s interests utilizing a history of the user’s interaction.
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Safi, Waseen. „Vibro-tactile Navigation of Web on touch screen devices“. Caen, 2016. https://hal.archives-ouvertes.fr/tel-01478756.
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Les personnes voyantes interprètent visuellement une grande quantité des informations visuelles et comprennent des mises en forme complexes des pages web en quelques secondes. Tout d'abord, ils naviguent une page web rapidement pour obtenir un aperçu global de la structure du contenu. Ce processus est appelé écrémage. Après, ils lisent le contenu des parties intéressantes en détails par suivant plusieurs méthodes de lecture. Ce processus est appelé balayage. Ce type de navigation des informations permet au lecteur de percevoir rapidement la mise en forme du document et sa sémantique structurelle. En outre, il oriente rapidement l'attention du lecteur sur les parties intéressantes de manière systématique et prévisible. Malheureusement, les personnes ayant une déficience visuelle ne peuvent pas faire cette interprétation dans la même efficacité. Ils perdent beaucoup de temps pour explorer l'architecture des pages web en utilisant les logiciels informatiques actuels spécialisés pour les personnes ayant une déficience visuelle. Ces logiciels présentent des styles d'interaction séquentielles pour naviguer des pages web, une colonne à la fois, une ligne à la fois, et un mot à la fois. Ces logiciels ne parviennent pas à transmettre l'ordre naturel des éléments sur une page web. L'interprétation de la disposition spatiale d'une page web est souvent indispensable pour comprendre son contenu, et il permet à l'utilisateur de traiter des informations complexes en la réduisant à un nombre gérable d'unités. La mise en forme, et les indices spatiaux des pages web sont très importants pour permettre nombreuses tâches, et pour guider l'utilisateur à analyser et à trouver des éléments de données, et pour réaliser de tâches plus compliquées tels stocker des informations, trouver rapidement les informations pertinentes, pointant directement toute information présente dans une page web. Ce travail présente une approche pour un accès non-visuel aux pages web. L'approche proposée est basée sur une modalité vibro-tactile pour remplacer le processus d'écrémage lors de la navigation des pages Web affichées sur des appareils mobiles avec écrans tactiles. L'approche aide les personnes ayant une déficience visuelle à obtenir un aperçu global de la structure du contenu, et de percevoir rapidement la mise en forme de la page web. L'approche a été réalisé par la conception d'un système de substitution sensorielle de la vision tactile. Ce système convertit les structures visuelles qui représentent la mise en forme d'une page web à des vibrations tactiles. Cette approche de navigation est équivalente à l'exploration visuelle classique d'un document sur la base d'une vibration de luminosité. En d'autres termes, les informations visuelles présentées sur les écrans numériques et qui sont obtenus par les méthodes de balayage visuel sont obtenues par une stratégie d'exploration manuelle basée sur l'interaction vibro-tactile. Cette approche proposée pourrait être considérée comme une nouvelle solution de navigation non-visuelle pour l'exploitation des informations spatiales des pages web. Des séries d'expériences ont été menées avec des personnes ayant une déficience visuelle a confirmé l'hypothèse que les personnes ayant une déficience visuelle peuvent explorer des formes géométriques graphiques présentés sur un appareil mobile avec un écran tactile, et ils peuvent percevoir leurs variétés de la taille, la forme, la topologie, les relations spatiales, et les contenus sémantiques en utilisant des vibrations tactilesSighted persons interpret visually a large amount of visual information and understand complex layouts of rich-media web pages in seconds. First, they navigate a web page by glancing it quickly to get a global overview of the content structure. This process is called skimming. After that, they read the contents of interesting parts in details by following various reading techniques. This process is called scanning. This type of information navigation enables the reader to perceive quickly the document layout and its structural semantics. In addition, it orients quickly the reader attention to interesting parts in a systematic and predictable manner. Unfortunately, persons with visual impairment cannot do this interpretation in the same efficiency. They lose a lot of time to explore the architecture of web pages using current computational products specialized for visually impaired persons. These products present sequential interaction styles to navigate the web, one column at a time, one line at a time, one word at a time. They fail to convey the natural ordering of elements in a web page. Interpreting the spatial layout of a web page is often indispensable to understand its contents. It helps the user in dealing with complex pieces of information by reducing them to a manageable number of units. The layout, and the spatial cues of web pages are very important in enabling many tasks, and in guiding the reader to analyze and to find data items, and in realizing high-level tasks such storing information, quickly finding relevant information, pointing directly to pieces of information present in a web page. This work presents an approach for non-visual access to web pages. The proposed approach is based on vibro-tactile modality to replace the visual skimming process during navigating web pages displayed on touch-screen mobile devices. It helps the visually impaired persons to get a global overview of the content structure, and to perceive quickly the web page layout. The approach has been realized by designing a tactile vision sensory substitution system (TVSS). This system converts the visual structures that represent the layout of a web page into vibro-tactile feedbacks. This navigation approach is equivalent to classical visual exploration of a document based on a luminosity vibration. In other words, the visual pieces of information presented on digital screens and obtained by the visual scanning methods are perceived by a manual exploration strategy based on vibro-tactile interaction. This proposed approach could be considered as a new non-visual navigation solution for exploiting the spatial two-dimensional information of web pages interfaces. A series of experiments has been conducted with visually impaired persons confirmed the hypothesis that visually impaired persons can explore graphical geometrical shapes presented on a touch-screen mobile device, and they can perceive their varieties in size, form, topology, spatial relations, and semantic contents through vibro-tactile feedbacks
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Ortiz, Boix Carla. „Implementing machine translation and post-editing to the translation of wildlife documentaries through voice-over and off-screen dubbing“. Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/400020.
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Aquesta tesi doctoral explora la possibilitat d’incloure la traducció automàtica i la traducció automàtica seguida de postedició en el procés de traducció de documentals científics de fauna i flora mitjançant veus superposades i doblatge en off. Per a aconseguir-ho, es van portar a terme tres estudis:
El primer estudi investiga els reptes que hauríem de superar per a poder introduir la traducció automàtica en el procés de traducció de documentals. Ens basem en estudis anteriors sobre traducció mitjançant veus superposades i doblatge en off i sobre traducció de documentals (per exemple, Franco et al., 2010) per a determinar els esmentats reptes, així com en l’anàlisi d’un corpus de guions de documentals en anglès, un corpus de documentals en castellà i un corpus de segments de guions de documentals i 9 traduccions, 8 de les quals van ser fetes per diversos motors de traducció automàtica en línia i gratuïts, i l’altra va ser traduïda per un professional. A més, l’estudi introdueix possibles solucions als reptes, que fem servir a l’experiment que presentem en el segon estudi.
El segon estudi se centra en un experiment per a determinar l’esforç necessari per a posteditar documentals científics de fauna i flora en comparació amb l’esforç requerit per a traduir-los. Dotze estudiants de màster van participar en l’experiment, que es va basar en la noció d’esforç de Krings (2001), així com en altres estudis sobre esforç de postedició (per exemple, O’Brien, 2006). Les conclusions de l’experiment indiquen que post-editar requereix menys esforç que traduir.
El tercer estudi compara la qualitat de documentals post-editats i traduïts. Per a fer-ho, es van portar a terme dos experiments. En el primer, sis experts van avaluar la qualitat dels documentals que van fer els estudiants de màster durant l’experiment del segon estudi. Així, doncs, els experts van posar nota als documents, els van corregir mitjançant una classificació d’errors basada en MQM que inclou especificacions per a la traducció documentals, i van respondre qüestionaris d’acord amb la seva opinió sobre les traduccions corregides. Les conclusions de l’experiment indiquen que la qualitat de les post-edicions i de les traduccions són significativament semblants.
En el segon experiment, 56 possibles usuaris van avaluar la qualitat dels documentals post-editats i traduïts mitjançant un qüestionari de recepció. Igual com va indicar l’avaluació dels experts, els resultats mostra que no hi ha diferencies significatives entre la qualitat dels documentals traduïts i els posteditats.
Els estudis presentats en aquesta tesi doctoral, doncs, permeten aconseguir l’objectiu principal de la tesi: “investigar si es podria incloure, satisfactòriament, la traducció automàtica, en quant a esforç i qualitat, en el procés de traducció de documentals d’un subdomini específic (fauna i flora) mitjançant veus superposades i doblatge en off; i validar les dues hipòtesis principals de la tesi: “esperem que la inclusió de traducció automàtica en el procés de traducció de documentals de naturalesa mitjançant veus superposades i doblatge en off optimitzi el procés en quant a esforç” i “esperem que la inclusió de traducció automàtica en el procés de traducció de documentals científics de fauna i flora per veus superposades i doblatge en off no afecti significativament la qualitat del producte traduït”.Esta tesis doctoral explora la posibilidad de incluir traducción automática y traducción automática seguida de post-edición en el proceso de traducción de documentales científicos de fauna y flora mediante voces superpuestas y doblaje en off. Para conseguirlo, llevamos a cabo tres estudios: El primer estudio investiga los desafíos que necesitamos superar para poder incluir la traducción automática en el proceso de traducción de documentales. Nos basamos en estudios anteriores sobre traducción mediante voces superpuestas y doblaje en off y sobre traducción de documentales (por ejemplo, Franco et al., 2010) para determinar los desafíos que nos podemos encontrar. También nos basamos en el análisis de un corpus de guiones de documentales en inglés, un corpus de documentales en español y un corpus de segmentos de guiones de documentales y sus nueve traducciones, ocho de las cuales fueron producidas por motores de traducción automática gratuitos y en línea, y otra traducción hecha por un traductor humano. Además, el estudio introduce posibles soluciones para estos desafíos, que usamos en el experimento presentado en el segundo estudio. El segundo estudio se centra en un experimento que pretende determinar el esfuerzo requerido para post-editar documentales de naturaleza comparado con el esfuerzo necesario para traducirlos. Doce estudiantes de máster participaron en el experimento, que se basó en la noción de esfuerzo de Krings (2001), así como otros estudios relacionados con esfuerzo de post-edición (por ejemplo, O’Brien, 2006). Las conclusiones del experimento parecen indicar que post-editar requiere menos esfuerzo que traducir. El tercer estudio compara la calidad de documentales post-editados y traducidos. Para hacerlo, se llevaron a cabo dos experimentos. En el primero, seis expertos evaluaron la calidad de los documentales hechos por los estudiantes durante el experimento: los expertos pusieron nota a los documentos, los corrigieron usando una clasificación de errores basada en el MQM que incluye especificaciones para la traducción de documentales, y respondieron unos cuestionarios sobre su opinión de las traducciones. Las conclusiones del experimento indican que la calidad de las post-ediciones y las traducciones son significativamente similares. En el segundo experimento, 56 posibles usuarios evaluaron la calidad de documentales post-editados y de documentales traducidos mediante un cuestionario de recepción. Igual como indicó la evaluación de los expertos, los resultados muestran que no hay diferencias significativas entre la calidad de los documentales traducidos y los post-editados. Los estudios presentados en esta tesis doctoral, pues, nos permiten conseguir el objetivo principal de la tesis: “investigar si se podría incluir la traducción automática de manera satisfactoria, en cuanto a esfuerzo y calidad, en el proceso de traducción de documentales de un subdominio específico (fauna y flora) mediante voces superpuestas y doblaje en off”; y validar las dos hipótesis principales de la tesis: “la inclusión de traducción automática en el proceso de traducción de documentales científicos de fauna y flora mediante voces superpuestas y doblaje en off optimizará el proceso en cuanto a esfuerzo” y “la inclusión de traducción automática en el proceso de traducción de documentales científicos de fauna y flora mediante voces superpuestas y doblaje en off no afectará significativamente la calidad del producto traducido”.
This PhD explores the possibility of introducing MT and PE MT into the process of translating wildlife documentaries to be voiced-over and off-screen dubbed. In order to do so, 3 studies have been carried out: The first stud researches the challenges that would need to be overcome if MT is to be included in the process of translating wildlife documentaries through VO and OD. The challenges are based on previous studies on the translation via VO and OD, and the translation of documentaries (e.g. Franco et al., 2010), as well as an analysis of a corpus of wildlife documentary scripts in English, a corpus of wildlife documentary scripts in Spanish, and a corpus of segments of documentary scripts and 9 translations: 8 produced by free-online MT engines and 1 by a human translator. Furthermore, it presents possible solutions to such challenges, which are used in the experiment presented in the second study. The second study presents and experiment that intends to determine the effort required to post-edit wildlife documentary films, as compared to the effort needed to translate them from scratch. 12 MA students participated in the experiment, which was based in Krings (2001) notion of PE effort, and previous experiments on PE effort (e.g. O’Brien, 2006). The conclusions of the experiments seem to indicate that PE requires less effort than translating them from scratch. The third study compares the quality of post-edited and translated wildlife documentaries. In order to do so, two experiments were carried out. The first one presents the QA, made by 6 experts, of the documentary scripts translated by MA students during the second study. The experts assessed the quality by grading the documents, by correcting them using an MQM-based error classification that includes specifications of documentary translation, and finally, by answering questionnaires on their opinions. Conclusions indicate that the quality of post-edited and translated wildlife documentaries is significantly similar. In the second experiment of the third study, 56 end-users blindly assessed the quality of post-edited and translated wildlife documentaries by using user-reception questionnaires. As well as the QA by experts, the results show that there is no significant difference between the quality of post-edited and translated documentaries. All the studies presented in this dissertation help to accomplish its main objective: “research whether MT might be successfully included, effort and quality wise, into the process of translating documentaries of a certain subdomain (wildlife) through VO and OD”; and validate its main hypotheses, which stand that “the inclusion of MT into the process of translating wildlife documentaries through VO and OD will optimize the process in terms of effort” and that “the inclusion of MT into the process of translating wildlife documentaries through VO and OD will not have significant impact on the quality of the translated product”.
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Kravchenko, Evgenija. „Association between cognitive measures, global brain surface area, genetics, and screen-time in young adolescents : Estimation of causal inference with machine learning“. Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290033.
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Screen media activity such as watching TV and videos, playing video games, and using social media has become a popular leisure activity for children and adolescents. The effect of screen time has been a highly debated topic; however, there is still very little known about it. Using a dataset from the Adolescent Brain Cognitive Development longitudinal study 4 217 young adolescents, that met the requirements, could be retrieved for this thesis project after processing of the data. This thesis project investigated causal order between genetic effect (cognitive performance Polygenic scores (PGSs)), screen time activity, brain morphology (structural Magnetic Resonance Imaging (sMRI) for surface area and cortical thickness), lack of perseverance, and cognitive performance (crystallized IQ) with a machine learning algorithm DirectLiNGAM. A clear correlation between screen media activity and PGS was found for all types of screen time activities but only video games and social media correlated to the global surface area. Furthermore, TV and video seem to affect lack of perseverance, and lack of perseverance, in turn, affects time spent on video games. These findings imply that different types of social media are not as alike as we thought and can affect adolescents differently. Taken together, these findings support previous research on screen media activity's effect on lack of perseverance, brain morphology, and cognitive performance, and propose new causal inference between genetics and screen time. Lastly, the algorithm used in this thesis project inferred reasonable causal orders and can be seen as a very good complement to today's causal modeling.Skärmaktivitet som att titta på TV och video, spela videospel och använda sociala medier har blivit en populär fritidsaktivitet för barn och ungdomar. Effekten av skärmtid har varit ett mycket debatterat ämne; det finns dock fortfarande mycket lite kunskap om det. Med hjälp av datasetet från Adolescent Brain Cognitive Development långtidsstudien kunde 4 217 ungdomar, som uppfyllde specifika krav, väljas ut för detta avhandlingsprojekt efter bearbetning av datan. Detta avhandlingsprojekt undersökte kausal ordning mellan genetisk effekt (Polygenic scores (PGS) för kognitiv prestation), skärmtidsaktivitet, hjärnmorfologi (strukturell Magnet Resonans Imaging (sMRI) för hjärnans ytarea och hjärnbarks tjocklek), brist på ihärdighet och kognitiv förmåga (kristalliserad IQ) med en maskininlärningsalgoritm DirectLiNGAM. Tydlig korrelation mellan skärmaktivitet och PGS hittades för alla typer av skärmaktiviteter men endast videospel och sociala medier korrelerade till den globala ytarean. Dessutom verkar TV och video påverka brist på ihärdighet och brist på ihärdighet i sin tur påverkar hur mycket tid som spenderas på videospel. Dessa resultat antyder att olika typer av sociala medier inte är så lika som vi trodde och kan påverka ungdomar olika. Sammanlagt stöder dessa upptäckter tidigare forskning om skärmtidseffekt på brist på ihärdighet, hjärnmorfologi och kognitiv förmåga och föreslår en ny kausal inferens mellan genetik och skärmtid. Slutligen ledde algoritmen som användes i detta avhandlingsprojekt fram till rimliga kausala ordningar och kan ses som ett mycket bra komplement till dagens kausala modellering.
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Fietz, Tom. „Entwurf und Berechnung einer Reihe elektrischer Kleinmaschinen mit siebgedruckten Wicklungen“. Master's thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-83634.
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Elektrische Maschinen werden heutzutage auf mannigfaltigen Gebieten eingesetzt. Sie verrichten ihre Aufgaben in leistungsstarken Industrieantrieben für Erzmühlen oder Stahlwalzen, als Synchrongeneratoren zur Elektroenergieerzeugung, in Fertigungsanlagen wie Backstraßen oder Fließbänder oder auch im Verkehr, in Zügen oder verstärkt nun auch in Automobilen.
Sie erleichtern uns aber auch den Alltag an Stellen, wo sie oft gar nicht wahrgenommen werden. Sie ermöglichen nützliche Helferlein im Auto mithilfe von Servomotoren – Scheibenwischer, Fensterheber oder Seitenspiegelverstellung sind nur ausgewählte Beispiele. Aber auch Fensterrollläden, Klimaanlagen oder Fahrstühle benötigen elektrische Antriebe. Darüber hinaus verstecken sich sie sich als Klein- und Kleinstmaschinen in medizinischen Geräten wie dem Zahnarztbohrer oder in Pflegeprodukten des täglichen Bedarfs von der Haarschneidemaschine, über den Nasenhaartrimmer und Föhn bis hin zur elektrischen Zahnbürste.
Da Elektromotoren also in immer mehr Geräten stecken, müssen auch immer größere Stückzahlen gefertigt werden, die am besten nichts kosten. Es besteht somit die große Herausforderung all die Bedürfnisse ressourcenschonend und kostengünstig zu bedienen. Aus diesem Gedanken heraus entstand am Lehrstuhl die Idee, Wicklungen elektrischer Kleinmaschinen zu drucken. Dies geschieht mithilfe der Siebdrucktechnik, wie es schon heute bei RFID-Chips die Regel ist. Es handelt sich also um ein erprobtes Verfahren, das eine günstige Fertigung großer Stückzahlen erlaubt.
Erste Erfahrungen wurden bereits gesammelt, hier sei auf [10], [11] und [12] verwiesen. Im Rahmen dieser Diplomarbeit sollen diese Grundlagen nun ausgebaut, gefestigt, sowie erweitert werden. Um einen Eindruck und Überblick zu gewinnen, wird im Folgenden eine Reihe elektrischer Kleinmaschinen entworfen.
Hierbei sollen Probleme ausfindig gemacht, Lösungen eruiert und Abweichungen zum konventionellen Entwurf aufgezeigt werden. Im Rahmen dessen werden Berechnungsvorschriften für siebgedruckte Wicklungen abgeleitet und diese schließlich zur Berechnung einer Maschinenreihe mit verschiedenen Außendurchmessern und Längen genutzt. Am Ende der Arbeit sollen ausgewählte Motoren aus der berechneten Reihe stehen, an denen Messungen stattfinden um die verwendeten Algorithmen zu verifizieren.
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Moulin, Renaud. „Dimensionnements et essais de moteurs supraconducteurs“. Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10051/document.
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L’actualité des travaux de recherche dans le domaine des moteurs électriques repose en partie sur des machines utilisant des matériaux supraconducteurs. En effet, ces matériaux des caractéristiques intéressantes pour des applications à champ magnétique et courant élevés, en étant refroidis à très basse température, en général de 4 à 77K. Ce qui est un paramètre important pour développer des machines de fortes puissances avec un encombrement minimal. Nous proposons d’utiliser les caractéristiques de fort courant et fort champ magnétique des fils supraconducteurs ainsi que les capacités de blindage magnétique des supraconducteurs massifs pour le développement de moteurs supraconducteurs. Nous avons développé et réalisé les essais d’une machine synchrone supraconductrice de 250kW, à inducteur supraconducteur tournant. Nous continuons les travaux sur les machines supraconductrices à topologies originales, avec la modélisation 3D d’un nouvel inducteur, à pans coupés. Mais également par de nouveaux essais et développements de la machine à concentration de flux magnétique réalisée dans des travaux précédentsAn important part of electrical machines research activities focus on superconducting motors. In fact, an important magnetic field and high current are possible with these materials, used at low temperature, generally 4 to 77K. These two parameters allow an interesting motor development, with higher electrical power and a minimal overcrowding. In front of high magnetic flux and high current superconducting caracteristics and bulk screening effect, we suggest several superconducting motors development. We developed and realized a 250kW synchronous superconducting motor, with a rotating superconducting inductor. Then, using 3D finite element software, we introduce an original superconducting inductor topology, nammed "pan coupé". Besides, we show new test and development of the magnetic flux concentration motor constructed 4 years ago
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Walbrou, Sonny. „Pour une histoire critique au prisme des rapports du corps à la machine, entre le cinéma, jeu vidéo et culture spectaculaire fin-de-siècle : continuité critique, innervation, attraction“. Thesis, Lille, 2018. http://www.theses.fr/2018LIL3H037.
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Entre hier et aujourd’hui, entre la culture spectaculaire de la fin du XIXe siècle, le cinéma et la pratique des jeux vidéo, cette thèse explore les enjeux critiques d’une pensée des rapports du corps à la machine au prisme de la notion benjaminienne d’innervation. A partir d’une notion historiographique élaborée au sein de la thèse, celle de « continuité critique » qui consiste à déterminer des phénomènes de permanence à travers l’histoire, notre travail vise à définir une critique opératoire des nouveaux médias. Depuis les notions d’innervation et de continuité critique, nous étudions dans une perspective historique et théorique deux « états du corps » déterminant des points de résonance manifestes entre passé et présent. L’un se situe au tournant du siècle, l’autre au cours des années 1980. Le premier concerne le devenir-attraction des machines autour de 1900. Dans le prolongement de Tom Gunning nous pensons une telle attraction dans les termes d’un corps à corps entre le spectateur et la machine. À travers la culture visuelle et spectaculaire fin-de-siècle, nous identifions un motif récurrent : le voyage immobile. Nous étudions alors l’actualité critique d’un tel motif jusqu’à nos jours comme quelque chose qui, en dépit des innovations techniques, n’a pas changé. Le second état s’intéresse cette fois-ci aux transformations qui concernent les rapports du corps à l’écran dans la pratique du jeu vidéo. Il s’agit d’étudier cette fois-ci un ensemble de représentations qui apparaissent entre le début des années 1980 et le milieu des années 1990 et attestant la récurrence d’un autre motif : l’écran traversé. L’étude de ces deux motifs nous permet, par le biais de l’histoire, de formuler une critique des nouveaux médias sur le terrain-même de la nouveautéBetween past and present, between the turn-of-the-century spectacular culture, cinema and video games, our thesis explores the critical aspects of body-machine relationships understandings regarding Walter Benjamin’s concept of innervation. From a historiographical concept formulated within this work, i. e. “critical continuity” which consists in crafting permanencies though history, our purpose is to delineate an operating critic of the new media. From the concepts of innervation and critical continuity, we explore two defining “state of body” to draw resonances between past and present. One takes place at the turn of the century while the other takes place during the 1980’s. The former concerns the becoming-attraction of the machines circa 1900. Extending Tom Gunning’s concept, we understand such an attraction as a corporeal relationship between the spectator’s body and the machine. Through 1900’s visual and spectacular culture, we examine a recurring topos: the immobile voyage. We find and explore the critical topicality of such a topos up to present day as something that has never changed despite technical innovations. The latter state explores the transformations regarding the body-screen relationships in video game practice. We study a collection of representations appearing between the early 1980’s up to the middle of the 1990’s featuring another recurring topos: the screen crossed whether by the game’s universe whether by the player. These two topoi help us to conceive a critic of the new media on the very basis of novelty
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Sommer, Matěj. „Alternativní řešení a pevnostní kontrola mechanických česlí“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417118.
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This master’s thesis deals with a new design of bar screens. The goal was to come up with an alternative design to already existing device by INKOS a. s. In the first part, there is a summary of various machines working in similiar conditions. The insights gained by this research influenced the design of the new device. It utilizes well proven solutions from previous projects, but some of these were reworked and a few new functions were added. Second part of the thesis describes the analytical solutions, which were used to determine the forces in the assembly during the operation of the device. Based on the results of these calculations, a strength analysis of important components was performed using the finite element method. The result of this thesis is the design and optimization of new bar screens, including engineering drawings and tools for its further development.
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Nysell, Kalle, und Charlie Adam. „Development of a Beam for a Vibration Motor“. Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19945.
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This project is centered around the use of finite element analysis for developing a beam for a new type of motor used in a screening machine. Essentially the main purpose of the developed beam is to transfer vibrations to the screen machine that it will be attached to. Since the machine operates on vibrations from the motor, the beam was to be designed with material fatigue in mind, which demanded examination of stresses in the welded joints of the beam. Concepts were generated with a specification of requirements as a basis, and the concepts were then analysed with finite element analysis. The results from this analysis were compared and a final design choice was selected. Since the beam will be subjected to varying fatigue loads, an S-N curve was needed to gain information of the material’s cyclic stress versus life. Most S-N curves are accessible through literature or databases, however, there are some materials that do not have an S-N curve available. If that is the case then the designer has the option to estimate one using ultimatetensile strength and the material’s fatigue limit. Hence, an S-N curve was estimated in this project.
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Sunnegårdh, Sandra, und Thea Svensson. „Touch Glaciem : The Touch Screen for Soft Ice Machines“. Thesis, KTH, Maskinkonstruktion (Inst.), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176628.
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The Chinese company Ocean Power manufactures and exports soft ice cream machines to companies worldwide. Their machines have high functionality and robust design that enables a low-cost manufacturing. All machines have a control panel where settings of the machine and the ice cream can be ranged. The control panel is at present designed in accordance with an old indigenous design tradition. With increasing international influence and contact, the need of functionality and design is changing. To stay competitive Ocean Power requests a change and an improvement of the control panel. The device needs to be intuitive and more attractive to the western as well as the domestic market. The purpose of this Bachelor Thesis has therefore been to develop a new, modern, userfriendly control panel that takes both cognitive and visual ergonomics into consideration. In order to make the control panel more intuitive and user-friendly, cognitive and visual ergonomics were studied. Different design theories and rules of how a control panels should be designed were taken into consideration. After exhaustive observations on Ocean Powers machines and an interview with Richard Cederwall, former employee of Ocean Power, a brainstorming session took place. The project members came up with various suggestions on the new control panel and its design. A returning theme in all the proposals was simplicity and intuitive symbols. A hierarchy map was then developed in order to group the machines functions into logical sub categories. During the projects development phase, it was decided that the new control panel should be a touch screen. This would allow a more flexible interface design, as well as give the ice cream machine an uplifting look and a feeling of exclusivity. To show what the touch screen with its interface, functions and graphics are meant to look like, a prototype was developed. The prototype is programmed for Android operating systems and will be demonstrated on an Android touch pad. This gives the viewer a realistic idea of what the interface could look like and how it would work.Det kinesiska företaget Ocean Power tillverkar och exporterar glassmaskiner till företag världen över. Deras maskiner har hög funktionalitet och robust design som möjliggör en billig tillverkning. Alla glassmaskiner har en kontrollpanel där inställningar av maskinen och dess mjukglass kan göras. Kontrollpanelen är idag utformad i enlighet med en äldre inhemsk designtradition. Med ökad internationell påverkan och med ökad internationell kontakt förändras kundernas krav på funktionalitet och design. Ocean Power ser därför en nödvändighet att förändra och förbättra kontrollpanelen till en mer intuitiv och attraktiv panel som attraherar även den västerländska marknaden. Syftet med detta kandidatarbete har därför varit att ta fram en ny mer modern, användarvänlig kontrollpanel som tar hänsyn till både kognitiv och visuell ergonomi. För att göra panelen mer intuitiv och användarvänlig samlades mycket fakta kring kognitiv och visuell ergonomi in. Olika designteorier och regler för hur kontrollpaneler bör utformas studerades. Efter en intervju med Richard Cederwall, tidigare anställd på Ocean Power och efter att maskinerna studerats noggrant utfördes en brainstorming där projektgruppen tog fram olika förslag på kontrollpaneler. Ett genomgående tema i alla förslag var enkelhet och intuitiva symboler. Därefter togs en hierarkikarta fram för att på ett logiskt sätt gruppera de olika funktionerna i underkategorier. Under projektets utvecklingsfas beslutades att den nya kontrollpanelen skulle bestå av en touch screen. En touch screen möjliggör för en mer flexibel design av gränssnitt samt ger hela glassmaskinen ett lyft och får den att kännas mer exklusiv. För att visa hur den tänkta touch screenen med dess gränssnitt, funktioner och grafik är tänkt att se ut har en prototyp tagits fram. Prototypen programmerades för ett Android operativsystem för att sedan kunna testas på en Android touch pad. På det viset kan användaren få en realistisk bild av hur gränssnittet är tänkt att se ut och fungera.
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From, Sebastian. „Split Screen Architecture : High speed data transmission in industrial machines and vehicles“. Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392099.
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This thesis examines different interfaces to suggest a concept of a split screen architecture for a company who develops and manufactures computers with integrated displays for industrial machines and vehicles. Splitting the display from the computer requires a high speed cable link between the display and the computer. This cable link must reach the mechanical and electromagnetic requirements of the intended environment the computers will operate in. Interfaces were found that can send the required video and control data over the same twisted pair or coaxial cables up to 15 m using serializers and deserializers. To send data in high speed puts tough electromagnetic requirements on the cable link as to not interfere or be interfered by nearby electrical systems. Electromagnetic properties of different cable solutions were compared to find a suitable cable that is not too expensive for the intended cable lengths. The study shows that there are interfaces available which can send several data types in a single cable so that a touch display can be positioned several meters away from the computer in demanding environments without losing the functionality it had when integrated in the computer.
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Cargill, Steven M. „Corona screen effectiveness in large machines under high voltage, high frequency transient conditions“. Thesis, Robert Gordon University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298316.
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Perejda, Michal. „Hydraulické shrabovací česle“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230545.
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This diploma thesis Hydraulic rake screen deals with the design of the hydraulic screen cleaning device with a stroke of 1800 mm, which will be placed in 1000 mm wide flow chanell of the wastewater treatment facility. This paper contains structural optimalization of the structure due to operating conditions and loads, mechanical strength calculations and drawings of the device and its details.
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Mag, Tobias Langston Richard. „From machines to screens the flattening effect in Christian Kracht's ""Faserland"" /“. Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,879.
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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Dec. 18, 2007). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Germanic Languages." Discipline: Germanic Languages; Department/School: Germanic Languages.
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Yu, Andrew Seohwan. „NBA ON-BALL SCREENS: AUTOMATIC IDENTIFICATION AND ANALYSIS OF BASKETBALL PLAYS“. Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu14943636475232.
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Quesada, Díaz Raquel. „Horseshoe Bending Machine : Bending Mechanism“. Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-9432.
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Horseshoes are manufactured metal plates developed in an extensive assortment of materials and shapes and their main function is to protect the horse’s hooves and legs against abrasion and rupture. After a certain period of time the horseshoes are lost, worn out, or the hoof needs to be treated. Horseshoeing is a repetitive time consuming process for the farrier who has to heat the horseshoe inside a forge until it reaches the required temperature and shape it with a hammer until it fits perfectly to the horses’ hoof. The main goal of this project is to develop a horseshoe bending machine able to shape the horseshoe so its shape fits perfectly the horse’s hoof. The calculation of the bending force needed to be applied to the horseshoe in order to provoke a plastic deformation will be done with Euler-Bernoulli beam theory. The bending force is then used to design and dimension each element of the bending mechanism so that it may be able to resist the stresses and prevent the parts from collapsing during its working life span. A study of the springback effect will be done followed by the analysis of the hertzian contact stresses between the rollers and the horseshoe. In addition, a clamping system is selected to constrain the movements of the horseshoe during the bending process. This machine will reduce the final user’s horse maintenance costs at the same time that makes the fitting process easier and less demanding, which will improve the farrier’s working life span and quality.
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Merritt, Andrew Stuart. „Conditioning of clay soils for tunnelling machine screw conveyors“. Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614729.
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Prince, Esther N. „Design of a genetic screen to identify novel components of the transcriptional machinery“. Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33827.
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We designed and engineered a yeast genetic screen to isolate novel transcriptional machinery components such as elongation factors and chromatin remodelling components. When artificially recruited to a promoter, these components can stimulate gene expression. For example, fusion of known machinery components to the bacterial DNA binding domain (DBD) of LexA results in activation of test genes bearing a binding site for LexA. In a previous study, the coding region of the LexA DBD was fused to random bacterial DNA sequences and, surprisingly, 1% of all random sequences tested were able to activate transcription simply because they were negatively charged. By inserting the LexA site downstream of the transcriptional start site of our reporter genes, we predict that we will exclude these same negatively charged sequences, which do not have a specific role in transcription. The rationale is that at this location classical activators, which are negatively charged, cannot activate transcription. The ability of transcriptional machinery components to activate transcription from a downstream location, however, was demonstrated. In order to isolate transcriptional machinery components, we prepared a yeast genomic DNA library fused to DNA encoding the LexA DBD for transformation into a yeast strain containing reporters bearing a downstream LexA operator site. Using this system, we may isolate novel components of the transcriptional machinery as well as already identified components. This genetic screen should also be able to isolate transcriptional machinery components from higher eukaryotic organisms.
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Rogers, Gregory Gilbert Juan E. „In election voting, do people touch the objective or not?“ Auburn, Ala, 2009. http://hdl.handle.net/10415/1721.
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Engelhardt, Andreas. „Investigation of several critical issues in screen mesh heat pipe manufacturing and operation“. Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11156/.
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The PhD thesis with the title “Investigation of several critical issues in screen mesh heat pipe manufacturing and operation” presented hereafter describes work carried out in four main areas. Initially the relevant literature is reviewed and presented, followed by the presentation of theoretical work regarding screen mesh heat pipe fill calculations, heat pipe processing and an investigation into the capillary or lifting height for screen mesh heat pipes. Further, the possibility of tailoring screen mesh heat pipes towards certain applications was investigated and it was found that further work is required in this area to allow a conclusive judgement whether a coarser or finer wick at the wall provides a distinguish advantage over two wraps of a medium coarse type. Within this approach a calculation method for the determination of the optimum working fluid fill of a screen mesh heat pipe based on geometrical parameters of the wick was developed and successfully implemented for the production of the later tested samples. The investigation into the effects of bending on the heat pipe performance, both using single phase flow CFD as well as experimentation, was performed using five different geometrical cases, each with five samples. These were tested in order to minimise the effects of sample variation. The test cases investigated contained the deformation angles of 0° (straight), 45°, 90°, 135° and 180°. During all test cases the orientation of the samples was kept constant at 0° to minimise additional influences like the effects of gravity on the reduction of available power handling capability. The test results show in deviation from CFD results that screen mesh heat pipe performance is significantly affected when bends are introduced and the reduction in power handling capability can be up to nearly 50% of a straight heat pipe value. Finally this thesis advances into the field of water heat pipe freeze thaw and the possibility of screen mesh heat pipes with changed shapes to withstand multiple freeze thaw cycles. It was found that correctly engineered screen mesh copper water heat pipes can be used in applications where they are subjected to multiple freeze thaw cycles. The fluid charge for water heat pipes subjected to these conditions needs to be adjusted in such a way, that accumulation of working fluid in certain areas, regardless of orientation or process variation during filling, is avoided.
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Kivila, Arto. „Touchscreen interfaces for machine control and education“. Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49051.
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The touchscreen user interface is an inherently dynamic device that is becoming
ubiquitous. The touchscreen’s ability to adapt to the user’s needs makes it superior
to more traditional haptic devices in many ways. Most touchscreen devices come with
a very large array of sensors already included in the package. This gives engineers
the means to develop human-machine interfaces that are very intuitive to use. This
thesis presents research that was done to develop a best touchscreen interface for
driving an industrial crane for novice users. To generalize the research, testing also
determined how touchscreen interfaces compare to the traditional joystick in highly
dynamic tracking situations using a manual tracking experiment.
Three separate operator studies were conducted to investigate touchscreen control
of cranes. The data indicates that the touchscreen interfaces are superior to the
traditional push-button control pendent and that the layout and function of the
graphical user interface on the touchscreen plays a roll in the performance of the
human operators.
The touchscreen interface also adds great promise for allowing users to navigate
through interactive textbooks. Therefore, this thesis also presents developments
directed at creating the next generation of engineering textbooks. Nine widgets were
developed for an interactive mechanical design textbook that is meant to be delivered
via tablet computers. Those widgets help students improve their technical writing
abilities, introduce them to tools they can use in product development, as well as give
them knowledge in how some dynamical systems behave. In addition two touchscreen
applications were developed to aid the judging of a mechanical design competition.
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Rane, Sham. „Grid generation and CFD analysis of variable geometry screw machines“. Thesis, City University London, 2015. http://openaccess.city.ac.uk/15129/.
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This thesis describes the development of grid generation and numerical methods for predicting the flow in variable geometry, positive displacement screw machines. It has been shown, from a review of available literature, that the two main approaches available to generate deforming grids for the CFD analysis of 3D transient flow in screw machines are algebraic and differential. Grids that maintain the cell count and connectivity, during solution, provide the highest accuracy and customised grid generation tools have the capability to accommodate large mesh deformations. For the analysis of screw rotors with a variable lead or varying profile, these techniques are suitable but are required to be developed further with new procedures that can define the three dimensional variation of geometry of the rotors onto the computational grid. An algebraic grid generation method was used for deforming grid generation of variable lead and varying profile rotors. Functions were developed for correlating a specified lead variation along the rotor axis with the grid spacing. These can be used to build a continuously variable lead with linear, quadratic or higher order functions. For variable profile rotors, a novel approach has been developed for three dimensional grid structuring. This can be used to specify a continuously variable rotor profile, a variable lead, and both internal and external rotor engagement, thus making it possible to generate rotor domains with conical and variable lead geometries. New grid distribution techniques were developed to distribute boundary points on the rotors from the fixed points on the rack and the casing. These can refine the grid in the region of interlobe leakage gaps between the rotors, produce a one to one connected interface between them and improve the cell quality. Inflation layers were applied and tested for mesh refinement near the rotor boundaries. Case studies have been presented to validate the proposed grid generation techniques and the results have been compared with experimental data. Simulated results agreed well with measured data and highlighted the conditions where deviations are highest. Results with variable geometry rotors showed that they achieve steeper internal pressure rise and a larger discharge port area could be used. With variable lead rotors the volumetric efficiency could be improved by reducing the sealing line length in the high pressure zone. Calculations with inflation layers showed that local velocities were better predicted but there was no substantial influence on the integral performance parameters.
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Scoditti, Adriano. „Gestural interaction techniques for handheld devices combining accelerometers and multipoint touch screens“. Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00665047.
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In this thesis, we address the question of gesture interaction on mobile device. These devices, now common, differ from conventional computers primarily by the input devices the user interact with (screen size small but tactile, various sensors such as accelerometers) as well as the context in which they are used. The work presented here is an exploration of the vast area of interaction techniques on these mobile devices. First we try to structure this space by focusing on the techniques based on accelerometers for which we propose a taxonomy. Its descriptive and discriminant power is validated by and the classification of thirty-seven interaction techniques in the literature. Second we focus on the achievement of gestural interaction techniques for these mobile devices. With TouchOver, we show that it is possible to take advantage of complementary two-channels input (touch screen and accelerometers) to add a state to the finger-drag, thus enriching the interaction. Finally, we focus on mobile device menus and offer a new form of sign language menus. We discuss their implementation with the GeLATI software library that allows their integration into a pre-existing GUI toolkit.
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Sari, Pelin. „Preliminary Design And Construction Of A Prototype Canola Seed Oil Extraction Machine“. Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607357/index.pdf.
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Growing energy demand in the world force people to investigate alternative energy sources. Unlike coal or other fossil fuels, renewable energy sources are promising for the future. Especially, seed oils are effectively used as energy sources such as fuel for diesel engines. The scope of this study is to develop an oil extraction machine specific to canola seed.
In this study, seed oil extraction methods have been investigated and various alternatives for the extraction machine have been considered. For continuous operation, oil extraction with a screw press is evaluated as the most appropriate solution. Four different prototypes have been designed and manufactured. According to the results of testing of prototypes, they have been modified and gradually improved to increase oil extraction efficiency. The working principle of the selected screw press based on the rotation of a tapered screw shaft mounted inside a grooved vessel. The screw shaft is a single square-threaded power screw having an increasing root diameter from inlet to exit while the outside diameter of the screw shaft is 66 mm. Seeds are taken into the system at the point where the depth of the screw thread is maximum. Then they are pushed forward by the threads on the rotating screw shaft and pass through inside the vessel. So, the fed seeds are compressed as they move to the other side of the vessel. Recovered oil escapes from high pressure zone and drains back. The oil is drained out from the oil drainage holes that are machined on high pressure zone of the vessel. Besides, the cake is extruded at the end of the vessel and the screw shaft. The cake thickness is adjustable by the axial movement of the screw shaft. By adjusting the cake thickness, different pressures can be obtained.
During the experiments, it is observed that four main features affect the oil recovery rate. These are the geometry of the grooves inside the vessel, the taper angle of the screw shaft, the operating temperature and the rotational speed. With the final prototype, an oil recovery efficiency of 62.5% has been achieved at 40 rpm with 15 kg/h seed capacity. Since the oil content of the seed is taken as 40%, oil recovery rate of the developed oil extraction machine is 3.75 kg/h. This efficiency is determined for a 0.8 mm cake thickness at 1.1 kW motor ower.
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Kovacevic, Ahmed. „Three dimensional numerical analysis for flow prediction in positive displacement screw machines“. Thesis, City University London, 2002. http://openaccess.city.ac.uk/7604/.
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A substantial proportion of all industrial compressors now produced are of the twin-screw type. These are rotary positive displacement machines, which operate at high efficiency over a wide range of speeds and pressure differences. Currently their performance is estimated by assuming simplified one-dimensional flow through passages with dimensions that are invariant with temperature and pressure. As manufacturing accuracy increases, clearances can be reduced and compressors thereby made smaller and more efficient. However to obtain full advantageo f this at the design stage,it must be possible to estimate accurately internal fluid flow patterns, pressure and temperature distribution and their effects on the working process. An interface has therefore been developed in order to generate a 3-D numerical grid for this purpose. This employs a procedure to produce rotor profiles and an analytical transfinite interpolation method with adaptive meshing to obtain a fully structured 3-D numerical mesh, which is directly transferable to a Computational fluid dynamics (CFD) code. Robust calculations can then be performed while allowing for moving, stretching and sliding between the rotors with large variations in the chamber shape and proportions. Changes in the solver functions have improved convergence and increased the speed of solution. One of these is to include a means to maintain constant pressure within the inlet and outlet ports throughout the calculating procedure. Also, the CFD procedure has been modified to enable fast calculations to be made with real working fluids and to estimate two-phase flow effects due to phase change and oil injection in the working chamber. The interface, pre-processing code and calculating procedures have been used with a commercial CFD solver to estimate the performance of three different compressor applications. The predicted results for one of these were compared with those obtained from the author's measurement in an experimental test rig and good agreement was obtained.
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Buckney, David. „Clearance management in twin screw compressors“. Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/18235/.
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Although the performance of twin screw compressors is heavily dependent on the rotor clearances within them, chamber models, used as design aids, allow for the specification of their magnitude and distribution but do not account for how these may vary during operation, as a result of internal temperature changes caused by the compression process. A validated procedure has therefore been developed to enable a chamber model to predict compressor performance, while including the effects of rotor and casing distortion resulting from dependant thermal effects. This has been achieved by the use of surface boundary mapping to calculate the rotor and casing temperature exposure within the compression chamber resulting from initial performance estimates. These detailed temperature distributions are processed analytically using appropriate assumptions that allow calculation of component temperatures and thermal growth. A program for calculation of leakage area curves has been adapted to support locally calculated variations in clearances. These updated area curves can then be fed back into the chamber model in an iterative procedure to simulate performance with thermally distorted clearances. The inclusion of thermal clearance corrections generally improved the accuracy of the chamber model when predictions from it were compared with test results over a wide range of operating pressures and temperatures. Furthermore, this work was found to be applicable in the evaluation of the interlobe clearance distribution between the rotors. Predicting clearance distortions and likely areas of rotor to rotor contact at a particular operating duty allows clearances to be optimised for the correct balance between performance and reliability; the results thus obtained were supported by findings from available test and tear down results.
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Dressler, Jan. „Konstrukce mobilního horizontálního štípacího stroje na dřevo“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229368.
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This thesis shows making of documentation for production powerfull wood-splitting machine for hardest forestal work. There are researched and soluted all phases of pre-production machine's lifecycle, also means analysis of conception, potentional risks and failures analysis and also definition of required properties. Based on those properties and results of analyses is possible to setting up condition which should be satisfied. At following part are descripted and shown features of machine-design . Main feature (component) of machine is its frame, also there are strenght analysis of frame. Machine movement features are mainly hydraulics pistons which are powered by asynchronous engine, whith alternative possibility movement by wheel tractor power-take off shaft or hydraulics output. There are performed all important properties. Working safety questions and high endurability of machine shold be also performed. At the end of work is realised conception and design study of forestal production system for wood processing with one universal source of energy – wheeled tractor.
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Holroyd, Geoffrey. „The modelling and correction of ball-screw geometric, thermal and load errors on CNC machine tools“. Thesis, University of Huddersfield, 2007. http://eprints.hud.ac.uk/id/eprint/2627/.
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In the modern global economy, there is a demand for high precision in manufacture as competitive pressures drive businesses to seek greater productivity. This results in a demand for a reduction in the errors associated with CNC machine tools. To this end, it is useful to develop a greater understanding of the mechanisms which give rise to errors in machine tool drives. This programme of research covers the geometric, thermal and load errors commonly encountered on CNC machine tools. Several mathematical models have been developed or extended which enable a deeper understanding of the interaction between these errors, various details of ballscrew design and the dynamic behaviour of ballscrew driven systems. Some useful models based on the discrete matter or “lumped mass” approach have been devised. One extends the classical eigenvalue method for finding the natural frequencies and other dynamic characteristics of ballscrew systems to include viscous damping effects using a generalised eigenvalue approach. This gives the damping coefficient of each predicted vibration mode along with the estimates of the natural frequencies, enabling many of the natural frequencies predicted by standard undamped natural frequency analyses to be dismissed as being of little consequence to the vibratory behaviour of the system. A development of this modelling method gives the sensitivity of the system to changes in stiffness and damping characteristics, which is helpful at the preliminary design stage of a ballscrew system, and is an aid in deciding the most convenient remedy to vibration problems which may occur in service. The second set of lumped-mass models is specially developed to take account of the changes in the configuration of the system with time as the nut moves along the screw while taking into account the non-linear phenomena of backlash and Coulomb friction. These can deal with the axial, torsional and transverse degrees of freedom of the system and predict many aspects of the dynamic behaviour of a ballscrew system which have an effect on the errors arising from such systems. They also include features which calculate the energy converted to heat by all the energy dissipative mechanisms in the model which can be used in conjunction with models already developed at the University of Huddersfield to predict thermal errors. Further, a strategy for compensation of some of these errors has been devised
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Bill, Brian Channing. „Pinball illustration : the artists and their careers /“. Related Electronic Resource: Web site of the Internet Pinball Database:, 2001. http://www.ipdb.org/.
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Thesis (M.A.)--Syracuse University, 2001."Submitted in partial fulfillment of the requirements for the degree of Master of Arts in Illustration in the Graduate School of Syracuse University." Includes bibliographical references.
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Patel, Purvi Shantilal. „Screw fixation of implants to the spine“. Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/849/.
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Bone screws are used to fix various implants to the human spine. Screw fixation can be difficult in osteoporotic bone because of its reduced strength. This research aimed to investigate screw fixation techniques in the spine. A questionnaire study, representing British and Irish spine surgeons, confirmed the potential for a simple screw positioning device and identified the need for an improved screw for osteoporotic bone. Determination of the compressive mechanical properties of 0.32 g.cm\(^{-3}\), 0.16 g.cm\(^{-3}\) and 0.09 g.cm\(^{-3}\) polyurethane foam enabled them to be used as models for normal, osteoporotic and very low density osteoporotic, human cancellous bone, respectively. The screw pullout force from these bone models decreased with polyurethane foam density, implying that the quality of bone principally influences the strength of screw fixation. The angle of screw insertion and thread design was also found to affect screw pullout force, but not a small amount of screw toggling prior to axial pullout. No benefits in pullout strength were found when placing screws at 40° in a normal bone model or when using closely placed multiple screws in an osteoporotic bone model.
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Chukanova, E. „Modelling of screw compressor plant operation under intermittent conditions“. Thesis, City, University of London, 2016. http://openaccess.city.ac.uk/15825/.
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Compressor plant frequently operates under unsteady conditions. This is due to pressure fluctuations, variable flow demand, or unsteady inlet conditions, as well as shaft speed variation. Also, following demand, compressor plants often work intermittently with frequent starts and stops. This may cause premature wear, decrease of compressor performance and even failure, which might cost millions of pounds to industry in downtime. However, there is still a lack of published data which describes intermittent plant behaviour, or predicts the effects of unsteady operation upon compressor plant performance. Thus, there appears to be a need to develop a mathematical model to calculate compressor plant performance during intermittent operating conditions and to verify this model with experimental data. Accordingly, this thesis describes an experimental and analytical study of screw compressor plant operating under unsteady conditions. For this purpose a one-dimensional model of the processes within a compressor was used, based on the differential equations of conservation of mass and energy, extended to include other plant components, such as storage tanks, control valves and connecting pipes. The model can simulate processes in both oil-free and oil-injected compressor plants during transient operation, including the effects of sudden changes in pressure, speed and valve area. Performance predictions obtained from the model gave good agreement with test results. This model can, therefore, be used to predict a variety of events, which may occur in everyday compressor plant operation.
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Strandberg, Marcus. „Determination and implementation of polymer parameters into simulations of the twin-screw extrusion process“. Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-27184.
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This thesis was conducted in cooperation with a Swedish company that develops and manufactures plastic compounds. An increasing need for identifying material properties is seen within the industry in order to predict the outcome of the extrusion process by using simulations. The purpose of this study was to expand a material database with the results obtained through various measurements of the material parameters in order to enable simulations. The numerical descriptions would be analyzed and validated in relation to the obtained results and conducted methods to enable implementation of the material data into the industry. In order to fulfill the purpose, scientific methods was applied by chosen literature studies, research approaches and experimental research. Machine tests were conducted to collect relevant output data that was compared with the results obtained during the simulation process where the experimentally determined material parameters were applied in a material database. Typical injection molding qualities of PET, POM, PC/ABS, SAN and PA66 has been investigated by conducting measurement methods described by standards of the melt flow rate, specific heats, viscosity, crystallinity and melt- and glass transition temperatures. With exception of the viscosity, the material parameters are considered to have high external validity and high reliability and can be implemented into the industry. The bulk- and melt density was determined by adapted methods that need further investigations. The external validity is reduced until these methods and measurements have been validated. The determined material parameters proved to be able to generate reliable simulation results that indicate of how the extrusion process will turn out based on the output values investigated. The data obtained through machine tests was compared with the results that were achieved through simulations and deviated at most 10.9% from the actual outcomes. The viscosity is considered to be the main factor that affects the differences of the output data between the machine tests and the simulation results.
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Schwartz, Scott Edward. „Development of the kinematic model for an ultrasound scanning machine by means of dual quaternion transformations of screw coordinates“. Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/104160.
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Mervin, Lewis. „Improved in silico methods for target deconvolution in phenotypic screens“. Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283004.
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Target-based screening projects for bioactive (orphan) compounds have been shown in many cases to be insufficiently predictive for in vivo efficacy, leading to attrition in clinical trials. Phenotypic screening has hence undergone a renaissance in both academia and in the pharmaceutical industry, partly due to this reason. One key shortcoming of this paradigm shift is that the protein targets modulated need to be elucidated subsequently, which is often a costly and time-consuming procedure. In this work, we have explored both improved methods and real-world case studies of how computational methods can help in target elucidation of phenotypic screens. One limitation of previous methods has been the ability to assess the applicability domain of the models, that is, when the assumptions made by a model are fulfilled and which input chemicals are reliably appropriate for the models. Hence, a major focus of this work was to explore methods for calibration of machine learning algorithms using Platt Scaling, Isotonic Regression Scaling and Venn-Abers Predictors, since the probabilities from well calibrated classifiers can be interpreted at a confidence level and predictions specified at an acceptable error rate. Additionally, many current protocols only offer probabilities for affinity, thus another key area for development was to expand the target prediction models with functional prediction (activation or inhibition). This extra level of annotation is important since the activation or inhibition of a target may positively or negatively impact the phenotypic response in a biological system. Furthermore, many existing methods do not utilize the wealth of bioactivity information held for orthologue species. We therefore also focused on an in-depth analysis of orthologue bioactivity data and its relevance and applicability towards expanding compound and target bioactivity space for predictive studies. The realized protocol was trained with 13,918,879 compound-target pairs and comprises 1,651 targets, which has been made available for public use at GitHub. Consequently, the methodology was applied to aid with the target deconvolution of AstraZeneca phenotypic readouts, in particular for the rationalization of cytotoxicity and cytostaticity in the High-Throughput Screening (HTS) collection. Results from this work highlighted which targets are frequently linked to the cytotoxicity and cytostaticity of chemical structures, and provided insight into which compounds to select or remove from the collection for future screening projects. Overall, this project has furthered the field of in silico target deconvolution, by improving the performance and applicability of current protocols and by rationalizing cytotoxicity, which has been shown to influence attrition in clinical trials.
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Bravo, Victor. „Finite element simulation of flow in twin screw extruder mixing elements“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/NQ42727.pdf.
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Jabbary-Aslani, Farnaz. „Design attributes of spinal fusion cages and a surgical instrument to aid thier screw fixation“. Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2952/.
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Spinal fusion cages are used to aid spinal fusion where the joint between the vertebrae is fused by bone graft. The design and material of these cages are of great importance to the fusion process. Methods such as screw fixation are sometimes used to secure these cages in vivo. However, access to the cage screw holes is partially obscured by the vertebral bodies. This study aimed to evaluate the effect of side-holes on the design of a cage, assess the feasibility of a bioactive/biodegradable composite as a cage material and develop an instrument to aid screw access to the cage screw holes. Computer models of cages with between 0 and 10 side-holes were produced to model compression between adjacent vertebrae. The bioactive/biodegradable composite as a cage material was analysed using a range of Young’s modulus values for the composite. The results suggested that the number of side-holes had a negligible effect on the stress distribution within the cage and the bioactive/biodegradable composite as a cervical cage material is unlikely to fail in static compression. A cutter instrument was developed in compliance with regulatory standards. It neatly removed the targeted vertebral edge adjacent to the cage screw holes allowing screw insertion.
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Mull, Jean-François. „Contribution à la modélisation du comportement dynamique du système de production composé de la machine et de ses outillages durant la phase de mise en forme. Application aux machines pilotées en énergie : de la presse à vis au pilon contre-frappe“. Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE057.
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L’enjeu du forgeage est la maîtrise des dimensions finales et des qualités métallurgiques du produit fini. Plusieurs phénomènes influencent le procédé dont le comportement de la machine. Les efforts importants mis en œuvre et les fortes décélérations des éléments en mouvement lors de la déformation de la pièce provoquent des phénomènes dynamiques à l’origine de pertes énergétiques. Sur les machines pilotées en énergie, dont font partie les presses à vis et les pilons, la mesure des efforts de forgeage et du déplacement des éléments en mouvement peut être complexe, du fait des conditions extrêmes en termes de température, de vitesse de frappe et d’énergie développée. C’est la raison pour laquelle, seuls des modèles théoriques sans liens directs avec la réalité ont été proposés pour représenter le comportement de ces machines. L’objectif de ces travaux est de développer une nouvelle méthodologie pour modéliser le comportement de la machine et de ses outillages, dans le but de rendre les simulations du procédé de forgeage plus prédictives. Le modèle et ses paramètres sont obtenus à partir de mesures expérimentales, ce qui fournit une solution sur-mesure, spécifiquement adaptée au système {machine + outillages} et applicable à une machine pilotée en énergie quelconque. Les méthodes numériques et les protocoles de mesure, nécessaires à la mise en œuvre de la méthodologie, sont développés pour trois technologies de machines. Le caractère prédictif du modèle est alors validé, étape par étape dans différentes configurations, jusqu’à la modélisation du comportement d’un pilon contre-frappe. En parallèle, le modèle est exploité pour quantifier l’efficacité du procédé et mieux comprendre les processus de consommation de l’énergie durant le forgeageThe issue in forging operations is to obtain final product with controlled geometries and microstructure. Several phenomena influence the process, of which one is the machine behavior. The high forging load and the important deceleration of moving parts during billet deformation cause dynamical phenomena which imply energy losses. For energy driven machines, as screw presses and hammers, the measurement of forging load and moving parts displacements can be complex, because of the extreme conditions concerning temperature, impact velocity and developed energy. Therefore, only theoretical models without direct links with reality have been proposed to represent machine behavior. The purpose of this work is to develop a new methodology to model the machine and tools behavior, in order to improve the predictivity of forging process simulations. The model and its parameters are obtained from experimental measurements, which provides a tailored solution, specifically adapted to the {machine + tools} system and applicable to any energy driven machines. The numerical methods and measurement protocols needed to apply the methodology are developed for three machine technologies. The predictive capacity of the model is then validated, step-by-step for different configurations, until reaching the modelling of a counterblow hammer. Simultaneously, the model is exploited to quantify process efficiency and better understand the energy consumption during forging operations
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Kolář, David. „Konstrukční návrh portálové CNC frézky s posuvným stolem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318840.
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This master’s thesis is focused on design of gantry CNC milling machine with sliding table. Thesis includes the review of components of this machines and comparsion of their options. Servo motors , ball screws and linear guides parameters are calculated. Also the suitable software and hardware for the machine control is chosen. Main parts of the machine were analysed using finite elements method. 3D model, drawings and documentation of machine build are included.
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Hanzal, Jiří. „Návrh malé modelářské CNC frézky s pevným stolem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-433604.
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The topic of this work is the design of a small model CNC milling machine with a fixed table for machining wood, plastic, or light alloys (Al, Zn, etc.). It also includes a calculation report and drawing documentation of selected nodes. The beginning of this work consists of an introduction to the issue of milling machines, their distribution and subsequent market analysis. Subsequently, the input parameters are designed on the basis of market analysis and in the last part there is a calculation report, the design of the milling machine itself and a short economic evaluation.
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Breuneval, Romain. „Surveillance de l’état de santé des actionneurs électromécaniques : application à l'aéronautique“. Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1313.
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L’industrie aéronautique fait face à trois enjeux majeurs : la réduction de son empreinte environnementale, l’absorption de l’augmentation du trafic et le maintien d’un haut niveau de sécurité pour des systèmes de plus en plus complexes, à coûts équivalents. La maintenance prédictive permet de répondre en partie à ces trois enjeux. Les systèmes, dont on peut prédire la durée de vie peuvent être utilisés plus longtemps, ce qui diminue le nombre de composants utilisés sur la vie d’un avion. Prédire les pannes permet également d’augmenter la disponibilité des aéronefs en évitant les arrêts non planifiés. Enfin, le suivi de l’état de vieillissement de l’avion permet d’optimiser la maintenance et ainsi de réduire les coûts. Dans les années 2000, ces méthodologies ont été appliquées sur les moteurs. Elles commencent maintenant à se généraliser aux autres systèmes avioniques. Ainsi cette thèse concerne la mise au point de méthodologies amenant à la maintenance prédictive d’actionneurs électro – mécaniques (EMA) de commande de vol. Les problématiques et les contraintes (temps de calculs, quantités de mémoire…) liées à cette thématique sont détaillées. Dans un premier temps, le calcul de signatures de défauts est abordé. Une méthode pour les systèmes visécrou, basée sur l’identification d’un modèle de frottement, est proposée. Une deuxième méthode, reposant sur l’analyse des courants à partir d’une combinaison de décomposition modale empirique ensembliste complète et d’analyse aveugle de sources, est ensuite introduite. Ces deux méthodes sont testées sur des données issues de profils non opérationnels. Ces données sont issues d’un modèle de simulation représentant finement l’actionneur dans son environnement. L’ensemble des simulations représente des essais virtuels sur une population d’EMA. A partir de ces simulations, les signatures mises au point sont calculées. Puis, afin de valider ces signatures, des métriques de performances sont calculées. Le diagnostic par reconnaissance de formes est ensuite traité. Un algorithme reposant sur une combinaison de machine à vecteur de supports et de fonctions floues d’appartenances est proposé. Celui-ci peut notamment estimer la sévérité d’un défaut. Il permet également de détecter des points ne correspondant pas à la base d’apprentissage, qui peuvent représenter des défauts inconnus ou des points appartenant à plusieurs classes à la fois, pouvant représenter des cas de défauts combinés. L’architecture d’un système de diagnostic complet, basée sur l’algorithme conçu, est détaillée. Des validations expérimentales des méthodes de calcul de signatures et de diagnostic sont ensuite menées. Ces validations reposent sur trois bases issues de trois campagnes d’essais. La première repose sur des essais d’un EMA sain sur un banc représentatif. La deuxième concerne un moteur asynchrone en défaut en régime permanent. La dernière porte sur un moteur synchrone à aimants, de type aéronautique, en défaut de courtcircuit inter-spires en régime permanent. Le respect des contraintes par l’algorithme est vérifié. Enfin, des éléments pour aller vers le pronostic sont avancés. Le processus du pronostic est détaillé. Seule une partie de ce processus est traitée, sur des données issues de vieillissement de roulements. Dans un premier temps, le partitionnement de données de vieillissement pour créer des classes de sévérité de défaut est étudié. Cette tâche a amené à proposer une métrique, dite de cohérence temporelle, permettant de vérifier qu’un résultat de partitionnement satisfait aux contraintes pour le pronostic. Puis l’algorithme de classification proposé est validé sur les données partitionnées. Ceci amène à distinguer deux méthodes de validation, une approche dite diagnostic et une dite pronostic. Une méthode de normalisation, pour l’approche pronostic, est proposée. La prédiction des signatures dans le futur est ensuite traitée. Un algorithme de régression par vecteurs de support est utilisé [etc...]The aeronautics industry is facing three major challenges: the reduction of its environmental impact, the absorption to the air traffic increase and a high level of safety for increasing complex systems, for equivalent costs. Predictive maintenance allows answering to these issues. Systems, for which the life can be predicted, can be used for a longer time. This reduces the number of components used in the lifetime of an aircraft. To predict failures also allow increasing the availability of aircrafts by avoiding unplanned downtime. Finally, monitoring the ageing of the aircraft allows to optimize maintenance and so to reduce costs. In the 2000s, these methodologies were applied to turbojets. It starts, now, to be generalized to others avionics systems. Therefore, this work deal with predictive maintenance methodologies for electromechanical actuator (EMA) for flight controls systems. Problems and constraints (computation time, memory quantities…) related to this subject are detailed. In a first part, fault feature computation methodologies are investigated. A first method is proposed for screw/nut systems. This method is based on the identification of a friction model. A second method, based on current analysis, is presented. This method uses a combination of empirical mode decomposition and independent component analysis. The two methods are tested on data from a non-operational profile. This data are from a simulation model which represents the EMA in the aircraft environment. The simulations performed represent virtual trials on a population of EMA. From these simulations, fault features are computed. Then, performances metrics are evaluated. Diagnosis by pattern recognition is then studied. An algorithm based on support vector machine and fuzzy membership functions is proposed. This algorithm can estimate the severity of a fault. It can also detect unknown observations, which can represent unknown faults or combined faults. The architecture of a global diagnosis system, based on the proposed algorithm, is detailed. Experimental validation of fault features computation and diagnosis algorithm is performed. These validations are based on three data bases. The first one is based on trials performed on a healthy EMA on a representative bench. The second consists in an induction motor at constant speed for different types of faults. The last one is from trials on a permanent magnet synchronous machine, of aeronautics type, for different kinds of short – circuit fault severities. The respect of the aeronautics constraints is verified. At last, elements for prognosis process are given. This process is detailed. Only a part of this process is treated, on a roller bearings benchmark database. First, the clustering for prognosis is studied. A metric, which allows verifying that the obtained clusters are coherent regarding time, and thus, checks the constraints for prognosis, is given. Then the proposed diagnosis algorithm is validated on the clustered data. This brought to perform two kinds of validation, a diagnosis oriented one and a prognosis oriented one. A method to normalize data for the prognosis oriented validation, based on sigmoid function, is given. The prediction of the features in the future is studied. A regression algorithm based on support vector regression is used. Finally, the diagnosis algorithm is applied to the predicted data. This allows to estimate the end of life, and so the remaining useful life for a given time. These estimations are evaluated regarding different kinds of performance metrics and regarding the constraints of the aeronautics applicative field
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Lužný, Jan. „Hydraulický čistící stroj“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416867.
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This diploma thesis deals with the design of hydraulic trash rack cleaning machine for waste water treatment plant. The first part of the thesis describes methods of removing coarse impurities from intake water to technological equipment. Furthermore, a specific design including calculation and choice of the drive is made. Part of the work is also solving the course of force effects and strength analysis of the most stressed parts. The work also deals with the comparison of design solution of hydraulic and mechanical drive of the machine. The attachment contains a drawing of the cleaning machine assembly and selected welded complex.
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Häggblom, Hanna. „Tillståndsbaserat underhåll på verktygsmaskiner : Utvärdering av det tillståndsbaserade underhållet på verktygsmaskiner hos Volvo Cars i Skövde och hur det kan utvecklas“. Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-10178.
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Företag kan använda sig av olika strategier för underhåll. Det kan vara avhjälpande underhåll som utförs först när ett fel uppkommer eller förebyggande underhåll. Ofta används en kombination av båda. Det förebyggande underhållet kan vara förutbestämt eller tillståndsbaserat. Fördelar med att använda sig av tillståndsbaserat underhåll är exempelvis att utbyte av enheter inte behöver ske i onödan utan först när en observation visar att ett fel är på väg att ske. Vid val av förebyggande underhåll kan RCM-metoden användas för att utröna vilka feltillstånd som kan uppstå och som orsakar funktionsfel. Val av förebyggande underhåll kan baseras på fakta om nya tekniker, felhistorik samt vilken utrustning och kompetens som finns tillgänglig. Volvo Cars i Skövde använder sig just nu av i stort sett likadant förebyggande underhåll på nya verktygsmaskiner som på gamla. Företaget använder sig av tillståndsbaserat underhåll på vissa komponenter och enheter. Det består då främst av inspektioner, subjektiva tillståndskontroller, och vibrationsövervakning på motorspindlar. Genom intervjuer framkommer att nya tekniker sällan införs och att lagda planer sällan ändras. Företaget är dock medvetet om att nya tekniker för tillståndsbaserat underhåll finns och är intresserat av att undersöka om ett utökat tillståndsbaserat underhåll är lämpligt på verktygsmaskiner. De tillståndsbaserade teknikerna som det talats om är främst ballbarmätning, övervakning av processparametrar och geometrisk verifiering. Ett underlag för att se om nya tekniker bör införas togs fram genom datainsamling av felhistorik på maskiner. Avgränsning gjordes genom att en fem år gammal bearbetningslinje för cylinderhuvuden studerades. Genom sortering av data från haverier ur underhållssystemet Maximo från de senaste åren och prioritering genom Paretoprincipen visade det sig att återkommande haverier på kulskruvar finns. Till komponenten finns ett tillståndsbaserat underhåll kopplat, den inspekteras en gång om året. Det är dock sällan som fel på komponenten upptäcks på inspektionen, bara fyra av tjugosju bytta kulskruvar de senaste fem åren är bytta efter anmärkning från inspektion. Genom att kartlägga komponentens haverier på femton verktygsmaskiner och när FU gjorts hittades flera förbättringsmöjligheter. Kostnaden för att byta kulskruv när väl fel uppstått är upp till tio gånger så stor jämfört med att byta den förebyggande. När fel uppstått har det medfört kassationer av producerade detaljer och lång stilleståndstid. Motiv för att införa ett bättre förebyggande underhåll finns därför framför allt i minskade kostnader och ökad tillgänglighet. Företaget rekommenderas att införa ballbarmätning som ett nytt tillståndsbaserat underhåll. Detta för att öka den objektiva kontrollen av mekaniska slitdelar. Mätmetoden är inte helt okänd för företaget och relativt lätt att införa. Den subjektiva kontrollen som görs idag bör göras om för att bättre fånga begynnelse till fel. Kontrollen kräver idag en hel del driftstoppstid vilket gjort att den inte utförts i tid och bör därför kortas ner. Företaget rekommenderas också att undersöka nya metoder för förebyggande underhåll kontinuerligt. Idag finns ingen anställd med uppdraget och för att utveckla underhållet måste företaget hålla sig uppdaterade på nya tekniker.A company can use different strategies when performing maintenance. One strategy is corrective maintenance where maintenance is carried out after a failure has occurred. Another strategy is preventive maintenance. A combination of the two is often used. The preventive maintenance can be predetermined or condition based. Advantages with the condition based maintenance are e.g. that the replacement of parts can be planned according to observations indicating there’s an increasing risk of failure. When choosing preventive maintenance, the RCM method can be used to determine risk of failure modes and the cause of function failures. Decisions regarding the preventive maintenance should be based on knowledge in new techniques, history of failures and the equipment and competence available. Volvo Cars in Skövde is doing more or less the same preventive maintenance on machine tools regardless of whether it’s a new or old machine. The company is using condition based maintenance on some of the components and units. Mostly it consists of human inspections, a subjective control of the machine’s condition, and spindle vibration analysis. Through interviews it has been determined that new techniques are rarely implemented and that the decided maintenance plan for a machine is rarely changed. The company is aware of the development of new techniques for condition based maintenance and wants to investigate whether it is appropriate to evolve their condition based maintenance on machine tools. The techniques further investigated are measurement with Ball bar, monitoring of process parameters and geometrical verification. To make accurate decisions regarding the implementation of new techniques, a data collection of the history of frequent failures was done. To limit the amount of data a five year old processing line was studied. Data from the maintenance system Maximo was sorted by long failures from the recent years and by prioritizing with the Pareto principle it showed the recurring failures of ball screws. The component do have a condition based maintenance activity today, there is an inspection once a year. However, the inspection is rarely able to predict or find a failure on the ball screw. Four out of twenty-seven ball screws with fault have been changed after inspection over the last five years. By mapping the components failures on fifteen machine tools and when preventive maintenance has been done, several options for improvements were found. The cost of the replacement of a ball screw when a failure has already occurred is as much as ten times the cost of replacement before failure. This is caused by cost of scrap and long down time. A new, improved preventive maintenance task is therefore highly justified. The motif is both reducing the scrap cost related to failure and with increased availability. The company is recommended an investment in Ball bar as a new method for condition based maintenance. It should be used to increase the objective control of the mechanical parts of a machine tool. The method is not totally new for the company and relatively easy to implement. The current subjective control on the machine tools should be revised to increase the probability of finding degradation of functions. Today the activity takes rather long time and has therefore not been done in time, it should be shorter. The company is also recommended to investigate new methods for preventive maintenance continually. Today there is no employee with that mission and to evolve maintenance, the company has to be updated on new techniques.
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Hellgren, Robin, und Martin Axelsson. „An evaluation of using a U-Net CNN with a random forest pre-screener : On a dataset of hand-drawn maps provided by länsstyrelsen i Jönköping“. Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-20003.
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Much research has been done on the use of machine learning to extract features such as buildings, lakes et cetera from satellite imagery, and while this dataset is valuable for many use cases, it is limited to time periods in which satellites were used. Historical maps have a much greater range of available time periods but the viability of using machine learning to extract data from these has not been investigated to any great extent. This case study uses a real-world use case to show the efficacy of using a U-Net convolutional neural network to extract features drawn on hand-drawn maps. By implementing a random forest as a pre-screener to the U-Net the goal was to filter out noise that could lead to false positives. By filtering out the noise the hope was to increase the accuracy of the U-Net. The pre-screener in this study has not performed well on the dataset and has not improved the performance of the U-Net. The U-Nets ability to extrapolate the location of features not explicitly drawn on the map was not clearly established. The results of this study show that the U-Net CNN could be an invaluable tool for quickly extracting data from this typically cumbersome data source, allowing for easier access to a wealth of data. The fields of archeology and climate science would find this especially useful.
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Imhof, David. „Empirical Methods for Detecting Bid-rigging Cartels“. Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCB005/document.
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Le projet de thèse présente différentes méthodes empiriques permettant de détecter des cartels. Il vise à démontrer premièrement que des résultats efficaces peuvent être obtenus avec de simples indicateurs statistiques et deuxièmement que les méthodes économétriques traditionnelles ne sont pas aussi efficacesThe PhD studies different empirical methods to detect bid-rigging cartels. It shows first that simple statistical screens perform very well to detect bid-rigging infringement. Second, the econometric method of Bajari, well established in the literature, produces poor results
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Betlach, Jakub. „Konstrukce konzoly s polohovacím stolem pro konzolovou frézku“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231334.
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This diploma thesis includes research in the structural parts of milling machines and designs of a console adjustable. This diploma thesis includes necessary calculations, adjustable worktable assembly drawing, selected drawing documentation, 3D model and model in an immersive virtual reality.
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Y, Lee C., und 李傳玉. „Machine Vision Detection of Monitor Screen Defects“. Thesis, 1998. http://ndltd.ncl.edu.tw/handle/13633457480277964566.
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Hsu, yen-chung, und 許顏忠. „Hybrid Fuzzy Controller Design for Slider Robot with Touch Screen Human-Machine Interface“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83377636203508686862.
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碩士國立勤益科技大學
電機工程系
100
The thesis presents a single-axis slider robot system design, including a slider robot mechanism, an electrical control system, a hybrid fuzzy controller, and a touch human-machine interface. The main objectives of this thesis are listed as follows. 1. Mechanism design of a single-axis slider robot The single-axis slider robot mechanism contains three parts, a slider, a slider fixed base, and a motor drive unit. The slider is installed on the upper plane of the fixed base to load the desired tools. The fixed base is composed of a number of pillars, fixed blocks, and belt adjustment structure. The belt is driven by motor drive unit, including a DC motor and a gear-box. The belt is connected to the mobile platform installed on the upper plane of the slider. Then the mobile platform can move freely on the slider by the motor drive unit. 2. Electrical control system design of the single-axis slider robot The electronic control system of single-axis slider robot is mainly composed of two modules, including a modular QVGA touch panel and a mother control board. The mother control board contains a control kernel, a DC motor drive circuit, a RS-232 communication port, a memory expansion circuit, and other required peripheral circuits. Mother control board can receive the commands from the QVGA touch panel or communication port. Depending on the command type, the control kernel executes the corresponding motion. It is beneficial to modular electrical control system design and promotes the flexibility of application. 3. Hybrid fuzzy controller design Controller plays an important role in the developed system. Regardless the position-loop or velocity-loop all requires a controller to achieve the desired performance, such as zero steady state error, fast rising time, and shorter settling time. This thesis proposes hybrid fuzzy controller design, integrating traditional PID controller and fuzzy controller, to obtain better performance, even though noise or load disturbance appears in the control process. The simulation and experimental results demonstrate the hybrid fuzzy controller outperforms than PID controller or fuzzy controller on the performance requirements described above. 4. Touch human-machine interface system design Generally, human-machine interface is based on a PC-based system in industry application. The user inputs the desired command from the PC-based system and then the control kernel executes the relative action. This structure requires an additional PC, thereby increasing the cost and size of the equipment. In order to reduce the equipment cost and size, using an embedded QVGA touch panel as the human-machine interface is the better choice. The developed QVGA human-machine interface achieves many advantages, such as low cost, simple, and friendly operation. Finally, all the developed system is implemented in the mechatronics laboratory. Integrating the mechanism, electrical control system, hybrid fuzzy controller, and the QVGA human-machine interface, the experimental results demonstrates the slider robot achieves fast and precise speed and position servo control. It can be applied to any single-axis robot system. Moreover, modular electrical control system is easily extended to multi-axis slider robot system.
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YE, JIN-HONG, und 葉晉宏. „Study on Preparation of Tio2 Film by Screen Printing Machine for Dye Sensitized Solar Cells“. Thesis, 2019. http://ndltd.ncl.edu.tw/handle/59y9d2.
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碩士國立虎尾科技大學
電子工程系碩士班
107
This work studies the preparation of the working electrode of the dye-sensitized solar cells. The thickness of the electrode of the working electrode, the uniformity of the coating layer, the surface condition of the electrode will affect the photoelectric conversion efficiency of the dye-sensitized solar cells. The effects of the screen printing parameters used for the preparation of the working electrode and the multilayer working electrode structure on the photoelectric conversion efficiency of the dye-sensitized solar cells were investigated. The screen printing technique requires a relatively high viscosity coating paste, compared to the coating paste for doctor blading method. This study used P25 and P100 TiO2 nanoparticle to prepare a suitable coating and printing paste. The uniformity of the coating layer is formed using the screen printing technique with the squeegee coating speed of 11 mm s-1, and we can also stack the multilayer TiO2 nanostructure to achieve a better thickness of the coating. The efficiency was as high as 4.77% when P100 was doped with 0.5g, and the efficiency was 4.86% when the amount of ethylcellulose was 0.25wt%.