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Emerson, Jessica Merrill Thurston. "Tag clouds in software visualisation." Thesis, University of Canterbury. Computer Science and Software Engineering, 2014. http://hdl.handle.net/10092/10120.
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Developing and maintaining software is a difficult task, and finding effective methods of understanding software is more necessary now than ever with the last few decades seeing a dramatic climb in the scale of software. Appropriate visualisations may enable greater understanding of the datasets we deal with in software engineering. As an aid for sense-making, visualisation is widely used in daily life (through graphics such as weather maps and road signs), as well as in other research domains, and is thought to be exceedingly beneficial. Unfortunately, there has not been widespread use of the multitude of techniques which have proposed for the software engineering domain.
Tag clouds are a simple, text-based visualisation commonly found on the internet. Typically, implementations of tag clouds have not included rich interactive features which are necessary for data exploration. In this thesis, I introduce design considerations and a task set for enabling interaction in a tag cloud visualisation system. These considerations are based on an analysis of challenges in visualising software engineering data, and the perceptive influences of visual properties available in tag clouds.
The design and implementation of interactive system Taggle based on these considerations is also presented, along with its broad-based evaluation. Evaluation approaches were informed by a systematic mapping study of previous tag cloud evaluation, providing an overview of existing research in the domain. The design of Taggle was improved following a heuristic evaluation by domain experts. Subsequent evaluations were divided into two parts - experiments focused on the tag cloud visualisation technique itself, and a task-based approach focused on the whole interactive system. As evidenced in the series of evaluative studies, the enhanced tag cloud features incorporated into Taggle enabled faster visual search response time, and the system could be used with minimal training to discover relevant information about an unknown software engineering dataset.
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Anderson, Jonathan. "Visualisation of data from IoT systems : A case study of a prototyping tool for data visualisations." Thesis, Linköpings universitet, Programvara och system, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138723.
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The client in this study, Attentec, has seen an increase in the demand for services connected to Internet of things systems. This study is therefore examining if there is a tool that can be a used to build fast prototype visualisations of data from IoT systems to use as a tool in their daily work. The study started with an initial phase with two parts. The first part was to get better knowledge of Attentec and derive requirements for the tool and the second part was a comparison of prototyping tools for aiding in development of data visualisations. Apache Zeppelin was chosen as the most versatile and suitable tool matching the criteria defined together with Attentec. Following the initial phase a pre-study containing interviews to collect empirical data on how visualisations and IoT projects had been implemented previously at Attentec were performed. This lead to the conclusion that geospatial data and NoSQL databases were common for IoT projects. A technical investigation was conducted on Apache Zeppelin to answer if there were any limits in using the tool for characteristics common in IoT system. This investigation lead to the conclusion that there was no support for plotting data on a map. The first implementation phase implemented support for geospatial data by adding a visualisation plug-in that plotted data on a map. The implementation phase was followed by an evaluation phase in which 5 participants performed tasks with Apache Zeppelin to evaluate the perceived usability of the tool. The evaluation was performed using a System Usability Scale and a Summed Usability Metric as well as interviews with the participants to find where improvements could be made. From the evaluation three main problems were discovered, the import and mapping of data, more feature on the map visualisation plug-in and the creation of database queries. The first two were chosen for the second iteration where a script for generating the code to import data was developed as well as improvements to the geospatial visualisation plug-in. A second evaluation was performed after the changes were made using similar tasks as in the first to see if the usability was improved between the two evaluations. The results of the Summed Usability Metric improved on all tasks and the System Usability Scale showed no significant change. In the interviews with the participants they all responded that the perceived usability had improved between the two evaluations suggesting some improvement.
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Samson, Duncan Alistair. "The heuristic significance of enacted visualisation." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1003434.
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This study is centred on an analysis of pupils' lived experience while engaged in the generalisation of linear sequences/progressions presented in a pictorial context. The study is oriented within the conceptual framework of qualitative research, and is anchored within an interpretive paradigm. A case study methodological strategy was adopted, the research participants being the members of a mixed gender, high ability Grade 9 class of 23 pupils at an independent school in South Africa. The analytical framework is structured around a combination of complementary multiple perspectives provided by three theoretical ideas, enactivism, figural apprehension, and knowledge objectification. An important aspect of this analytical framework is the sensitivity it shows to the visual, phenomenological and semiotic aspects of figural pattern generalisation. It is the central thesis of this study that the combined complementary multiple perspectives of enactivism, figural apprehension and knowledge objectification provide a powerful depth of analysis to the exploration of the inter-relationship between the embodied processes of pattern generalisation and the visualisation of pictorial cues. The richly textured tapestry of activity captured through a multi-systemic semiotic analysis of participants' generalisation activity stands testament to this central thesis. Insights gleaned from this study are presented as practical strategies which support and encourage a multiple representational approach to pattern generalisation in the pedagogical context of the classroom.
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Rozendaal, Ross. "Interactive visualisation using 3D graphics : an archaeological case study." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/4980.
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Bibliography: leaves 82-84.The methods of displaying data from archaeological surveys are of considerable importance in representing realistic impressions of archaeological sites that few people are able to visit. In many cases, further study of a site is not possible at the location of the site. This would require that the surveyed data of the site be displayed in such a way as to be accurate and realistic as well as including interactive tools, enabling further studies. Traditional displays of archaeological data have been either in textual form or in the conventional hardcopy form of maps and drawings. With the advent of computers and computer graphics alternative methods of displaying the data have become possible. 3D graphics have become an important method of displaying archaeological data. In 1995 and 1996 the Department of Geomatics at the University of Cape Town participated in the survey of the 3.6 million year old hominid footprints in Tanzania. The survey was required for the documentation and study of the footprints. In order to facilitate this in 3D graphics, software packages that allowed user interactive tools to be included in the display had to be investigated. Methods of displaying the data also had to be investigated. Java3D was selected to create the 3D models and user interactive tools that included measurement tools, gradient tools and profile tools. These tools were created for the Laetoli footprints but were applicable in other archaeological displays as well.
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Beattie, Robert. "The creative entrepreneur : a study of the entrepreneur's creative processes." Thesis, Abertay University, 1999. https://rke.abertay.ac.uk/en/studentTheses/9dfc2bf2-fb0e-4609-9c13-a35fce053cbc.
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The aim of the research was to increase the understanding of how the entrepreneur’s process of creativity began and evolved by determining how ideas and opportunities were discovered, recognised and harnessed prior to the advent of entrepreneurship. There appeared to be a shortage of appropriate research studies into the entrepreneur’s creative processes, describing how it began and evolved over time. There also appeared to be few studies that attempted to describe how entrepreneurs discovered their ideas, harnessed them, and converted them into opportunities. It would seem that the majority of the empirical research studies on the subject have focused upon managers and founders of companies compared to studies involving nascent entrepreneurs and entrepreneurs. The objective of the research study was to provide a new synthesis of the research literature in order to create a framework that described the key cognitive processes and personal attributes that were involved in the entrepreneurs’ search and evolution of their ideas. The content and elements of the framework were then compared with the context of the entrepreneurs’ personal histories in order that generic themes could be identified. After a period of one year, further interviews were held with the entrepreneurs in order to monitor any changes to the processes involved. The research began with a review of existing literature relating to the entrepreneur and entrepreneurship. A selective review of the historical research literature on the entrepreneur was followed by an appraisal of some of the entrepreneurs’ attitudes and behaviour patterns. This provided a thumbnail sketch of each entrepreneur, his or her origins, and what he or she did. This was followed by a description of what might be construed as a typical nascent entrepreneur. This description detailed the process from the ‘learning phase’ to the ‘triggering event’ that caused such a dramatic change in his or her career path, i.e. the critical incident that set off a mental chain reaction within the nascent entrepreneur that led to the establishment of his or her entrepreneurial intentions. A review of the research literature concerning the focal theory of the research objectives led to an in-depth appraisal of what is meant by ‘creativity’ and ‘cognitive processes’. The difficulties of researching such subjective actions are shared by previous research literature. The creative variables were then brought together in a number of phases contained in the discovery and evolution processes. The process was then followed through the discovery phase, stressing the importance of the prepared mind to the birth of the idea. The various thinking and analytical processes involved in the evolution of an idea into an opportunity were discussed in the context of an entrepreneur’s core attributes and beliefs. The focal theory review concluded with a framework of the elements appertaining to the research objectives that had been derived from the research literature. The structure and elements of the framework were then compared with the relevant data from the field research study. A number of research questions arose from the key issues raised in the research literature. These concerned, having a prepared mind, happenstance, intuition, self-belief, values, visualisation and goal setting. The sample of the population chosen for the research study comprised fifty Scottish entrepreneurs of both sexes and varying sizes of company, ages of business, turnover and number of employees. The companies with whom entrepreneurs were involved covered various industries and activities. Following the guidance obtained from the research literature, in-depth interviews were carried out. A number of the entrepreneurs interviewed were subjected to a follow-up meeting after one year, in order to monitor any further developments and changes to the themes identified from the first interviews, and to provide the research with a further means of validation. An opportunity was taken at the meeting to share with the entrepreneurs the preliminary findings arising from the previous interviews. The interviews were tape-recorded, transcribed, and data was computerised. The data was then subjected to content analysis, as was the secondary information obtained from publications, newspaper articles and other case studies. The research findings identified many generic themes among the entrepreneurs, particularly in the area described as the discovery and evolution phases of the creative process. A high percentage of entrepreneurs also had beliefs and attitudes that were similar to their business philosophy. The findings supported a number of theories that have been outlined previously in the research literature, as well as confirming many of the traits, characteristics and behaviours attributed to being entrepreneurial. The findings of the research confirmed that many of the entrepreneurial ideas occurred serendipitously, and the use of visualisation and rehearsal techniques was considered by many to be invaluable in the creative process. Goal setting also appeared to provide essential stepping stones to the monitoring and attainment of many successful outcomes, particularly in the evolution stage. The structure and elements of the framework of the process of creation appeared to be well supported by the majority of the entrepreneurs interviewed. Recommendations are made as to how the adoption of some of the research findings could assist in the encouragement and advancement of an enterprise learning culture, and the establishment of a ‘can-do’ attitude towards enterprise creation.
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MartiÌnez-GarciÌa, Elvira. "Experimental and numerical study on the thermo hydraulic behaviour in a wavy plate heat exchanger using Newtonian and non Newtonian fluids." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271803.
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Mabakane, Mabule Samuel. "Effective visualisation of callgraphs for optimisation of parallel programs: a design study." Thesis, Faculty of Science, 2019. http://pubs.cs.uct.ac.za/archive/00001309/.
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Parallel programs are increasingly used to perform scientific calculations on supercomputers. Optimising parallel applications to scale well, and ensuring maximum parallelisation, is a challenging task. The performance of parallel programs is affected by a range of factors, such as limited network bandwidth, parallel algorithms, memory latency and the speed of the processors. The term “performance bottlenecks” refers to obstacles that cause slow execution of the parallel programs. Visualisation tools are used to identify performance bottlenecks of parallel applications in an attempt to optimize the execution of the programs and fully utilise the available computational resources. TAU (Tuning and Analysis Utilities) callgraph visualisation is one such tool commonly used to analyse the performance of parallel programs. The callgraph visualisation shows the relationship between different parts (for example, routines, subroutines, modules and functions) of the parallel program executed during the run. TAU’s callgraph tool has limitations: it does not have the ability to effectively display large performance data (metrics) generated during the execution of the parallel program, and the relationship between different parts of the program executed during the run can be hard to see.
The aim of this work is to design an effective callgraph visualisation that enables users to efficiently identify performance bottlenecks incurred during the execution of a parallel program. This design study employs a user-centred iterative methodology to develop a new callgraph visualisation, involving expert users in the three developmental stages of the system: these design stages develop prototypes of increasing fidelity, from a paper prototype to high fidelity interactive prototypes in the final design. The paper-based prototype of a new callgraph visualisation was evaluated by a single expert from the University of Oregon’s Performance Research Lab, which developed the original callgraph visualisation tool. This expert is a computer scientist who holds doctoral degree in computer and information science from University of Oregon and is the head of the University of Oregon’s Performance Research Lab. The interactive prototype (first high fidelity design) was evaluated against the original TAU callgraph system by a team of expert users, comprising doctoral graduates and undergraduate computer scientists from the University of Tennessee, United States of America (USA). The final complete prototype (second high fidelity design) of the callgraph visualisation was developed with the D3.js JavaScript library and evaluated by users (doctoral graduates and
undergraduate computer science students) from the University of Tennessee, USA. Most of these users have between 3 and 20 years of experience in High Performance Computing (HPC). On the other hand, an expert has more than 20 years of experience in development of visualisation tools used to analyse the performance of parallel programs. The expert and users were chosen to test new callgraphs against original callgraphs because they have experience in analysing, debugging, parallelising, optimising and developing parallel programs. After evaluations, the final visualisation design of the callgraphs was found to be effective, interactive, informative and easy-to-use. It is anticipated that the final design of the callgraph visualisation will help parallel computing users to effectively identify performance bottlenecks within parallel programs, and enable full utilisation of computational resources within a supercomputer.
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Tshithigona, Gaus. "An investigation into teaching mathematics using a visualisation approach to recontextualise indigenous knowledge." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62461.
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It can be argued that the Namibian curriculum is largely influenced by a Western epistemology. However, many studies suggest that learners make powerful meanings of mathematical concepts they are learning if they visualise these and experience them in relation to what they already know from their own cultural backgrounds. According to the Namibian National Curriculum for Basic Education (NNCBE, 2010), it is not only important for learners to acquire mathematical knowledge and skills, but also to develop and grow their identities, cultures and values as individuals. The aim of this study was to explore and investigate how selected mathematics teachers employ visualisation as a teaching approach to re-contextualise indigenous knowledge (IK). The study set out to explore how conceptual understanding is enhanced by participation in an intervention programme. The use of visualisation is considered an important mediating and pedagogical tool in the mathematics classroom to enhance the mathematics learning of learners. The research is informed by a socio-cultural theory of learning and is located within an interpretive paradigm. The study was conducted at four schools in the Oshana region of Namibia and involved four mathematics teachers who were purposefully selected due to their willingness to use visualisation-IK approaches in their teaching, based on their responses to the survey. The methodologies used are qualitative and quantitative case study. To gather data, document analysis, a survey, lesson observations and focus group interviews were used. The study found that most teachers in the Oshana region have an understanding of the effective use of visualisation-IK approaches. However, the study revealed that visualisation- IK approaches are mostly used in grades 4 to 7 mathematics classrooms. It also discovered that most of the visualisation approaches that teachers employed aligned well with the curriculum and promoted conceptual understanding in the teaching of mathematics. The results of the study showed that teachers have experience of the enabling and constraining factors in using a visualisation-IK approach to teaching mathematics.
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Runge, Katharina. "Visualisation de fluxoides dans des réseaux 2D artificiels supraconducteurs." Phd thesis, Grenoble 1, 1993. http://tel.archives-ouvertes.fr/tel-00356016.
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Nous avons mis au point une cellule de décoration, permettant de décorer les vortex à basse température (jusqu'à 1.6K) sous faible champ magnétique (jusqu'à 0.2mT). La méthode est basée sur l'interaction des gradients de champs dus aux vortex avec des particules ferromagnétiques fabriquées in-situ dans un gaz résiduel. Après réchauffement, l'observation des amas de nickel se fait sous le microscope électronique à balayage. Les échantillons étudiés sont des réseaux 2D submicroniques de fils en niobium (pas du réseau 1-2 µm, largeur des fils 0.3 µm, épaisseur 0.2 µm) avec d'excellentes propriétés supraconductrices (température de transition 9.0K, RRR d'environ 30). Notre calcul de profil de champ magnétique au-dessus d'un réseau montre que le contraste entre cellules avec ou sans vortex est extrêmement faible. Suivant la hauteur au dessus du réseau, nous décorons soit les courants soit les milieux de cellules. La décoration se fait donc sur des réseaux planarisés, à des températures T<
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Johansson, Sofia. "Usability through visualisation : A case study of ISO 26262 at Scania R&D." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217842.
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The average person today is more informed compared to the most informed people 25 years ago, however, he or she knows a lower percentage of all available information than those in the 80’s. In today’s society, information is flowing everywhere and through all mediums. Research shows that this constantly accessible information is hampering our daily work– if not presented in an accessible way. This thesis has investigated this particular issue with ISO 26262 as case. ISO 26262 is a standard concerning the safety within E/E –systems and is currently being adopted at Scania. However, the users think the standard, which is originally presented in a pdf document, is both time –and resource inefficient, and also the content of ISO 26262 is presented in such manner that it can be interpreted in multiple ways, and is experienced as a “wall of text”. By carrying out several user interactions, it was discovered that the most critical issue for the users was looking for information and that the standard would be more user friendly if presented in a website. Adjustments of the text and layout within the standard were made based on the conducted literature study, such as a stronger hierarchy of the content, spacing and construction of sections. The approach of the project was based on service design, in order to maintain focus on the user and usage, which during the user interactions were discovered to be the two main areas that had to be investigated, problematised and solved. The user and usage areas were therefore iteratively implemented through all four stages of the approach; exploration, creation, reflection and implementation, which led the final result of a website and its construction, links and layout. The assumed most critical parts of the final website were implemented in order to ensure a fulfilment of the main criteria generated from the user interactions. However, if more time had been available, the website could have been user tested once more, in order to find further critical aspects and ensure their fulfilment.Genomsnittspersonen är idag mer informerad jämfört med de mest informerade personerna 25 år sedan, men trots det så vet han eller hon en lägre andel av all tillgänglig information, jämfört med de mest informerade på 1980-talet. I dagens samhälle flödar information överallt och genom alla typer av medium. Forskning visar att detta ständiga informationsflöde kan störa oss i vårt dagliga arbete – om den inte presenteras för oss på ett tillgängligt sätt. Denna uppsats har undersökt just detta problem, med ISO 26262 som fallstudie. ISO 26262 är en standard som behandlar säkerheten i E/E –system, som för tillfället är under tillämpning av anställda hos Scania. De anställda tycker dock att standarden, som tillgängliggörs i ett pdf dokument, är för tids- och resurskrävande. Innehållet i ISO 26262 är också presenterat på ett sätt som gör standarden öppen för olika tolkningar, och de anställda upplever dokumentet som en ”vägg av text”. I detta projekt har flera användarundersökningar genomförts, och under dessa fastställdes det mest kritiska momentet för användarna till att leta upp information i standarden, och för att göra ISO 26262 mer användarvänligt föredrogs en hemsida. Ändringar i texten har gjorts, med grund i den litteraturstudie som genomförts, där till exempel hierarkin i texten har förstärkts, mellanrum har anpassats och upplägget av kapitel och delkapitel har ändrats. Arbetssättet under projektet har grundats i tjänstedesign, för att bibehålla fokus på användare och användning, vilka genom användarundersökningarna upptäcktes vara de två huvudområdena att vidare undersöka. Dessa två områden arbetades igenom på ett iterativt sätt, inkluderande dom fyra huvudstegen; utforskning, skapning, reflektering och implementation, vilket resulterade i konstruktionen av en hemsida samt dess layout. Den slutgiltiga hemsidan antas uppfylla de huvudkriterierna som upptäcktes under användarundersökningar, men om mer tid hade funnits så kunde hemsidan ha blivit användartestats en gång till, och på så vis säkerställa att alla kritiska aspekter upptäckts och åtgärdats.
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Muhembo, Gottfried Mbundu. "An analysis of how visualisation processes can be used by teachers participating in an intervention programme to teach for conceptual understanding of geometry." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62439.
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Visualisation in general and visualisation processes in particular have received much attention in the mathematics education research literature. Literature suggests that the appropriate use of visualisation helps learners to develop their conceptual understanding and skills of geometry as it allows them to visually interpret and understand fundamental mathematical and geometrical concepts. It is claimed that visual tools play an important role in communicating mathematical ideas through diagrams, gestures, images, sketches or drawings. Learning mathematics through visualisation can be a powerful tool to explore mathematical problems and give meaning to mathematical concepts and relationships between them. This interpretive case study focused on how selected teachers taught concepts in geometry through visualisation processes for conceptual understanding as a result of an intervention programme. The study was conducted at four high schools by four mathematics teachers in the Kavango East Region in Northern Namibia. The participants were involved in a three-week intervention programme and afterwards taught three lessons each on the topic of geometry. The data collection method of this research was: focus group and stimulus recall interviews, classroom observations and recorded videos. This research is located in constructivism. I used vertical and horizontal analysis strategies to analyse the data. My analytical instrument consisted of an observation schedule which I used in each lesson to identify how each of the visualisation processes was evident in each of the observed lessons. This study revealed that the participant teachers used visualisation processes in most of their lessons and these processes were used accurately in line with the requirements of the grade 8 mathematics syllabi. The visualisation processes were used through designed visual materials, posters and through the use of geometrical objects such as chalkboard ruler, protractor and compass. The results from this study also confirmed that visualisation processes can be a powerful instructional tool for enhancing learners’ conceptual understanding of geometry.
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Vitale, Valeria. "Rethinking 3D visualisation : from photorealistic visual aid to multivocal environment to study and communicate cultural heritage." Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/rethinking-3d-visualisation(7079ff9d-6e19-4335-a3e6-fc53bf69620c).html.
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This research presents the issue of opacity in 3D visualisations of cultural heritage and explains how it prevents 3D technologies from being used to their full extent in an academic context. The impossibility to assess the provenance of the sources, cite references or identify individual contributions make the majority of available 3D models closer to mere illustrations than tools for the study and understanding of the past, regardless the amount of research that has informed the creation of the visual output. An analysis of some of the existing strategies of documentation of 3D visualisations highlights the current lack of a standard, or even a common language, that would make such documentations comparable and cross searchable. This work suggests the use of a simple, sustainable and well-established technology as Linked Open Data, together with a tailored domain ontology, as a possible approach. The use of the synthetic and formalised vocabulary of an ontology, with its classes and properties, is used experimentally, as a proof of concept, to document the 3D visualisation of an ancient building, the Iseum in Pompeii, and to connect each part of the model to the documents that have been used as sources. The proof of concept also shows how the application of LOD technology can, potentially, change the way 3D visualisation is used in academia, not only making 3D models documented and, therefore, closer to a scientific publication, but, also, encouraging exchange and reuse of data and facilitating preservation. The thesis discusses the rationale behind the creation of the ontology, its application to the documentation of a complex 3D model and its contribution towards a collaborative and transparent use of 3D technologies in academia. The 3D models, the ontology, and the text are equally important components of this work.
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Ge, Ning. "Contribution à l'étude du décollement tournant dans les ventilateurs axiaux par vélocimétrie Doppler à laser et visualisation." Valenciennes, 1993. https://ged.uphf.fr/nuxeo/site/esupversions/4e75b118-426c-4ae9-aa47-2cc24195edb4.
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Dans un ventilateur axial, le décollement tournant peut être caractérisé par des cellules à débit réduit, nul ou négatif qui se propagent dans le sens de la rotation du ventilateur à une vitesse angulaire constante. L'objectif de notre travail a consisté à utiliser les méthodes expérimentales telles que la vélocimétrie laser, le fil chaud et la technique de visualisation pour étudier l'apparition de ce phénomène. En général, les sondes perturbent l'écoulement. La mesure sans contact du fluide par vélocimétrie laser nous permet une approche plus fine du phénomène étudié. Des fils chauds simples ont été utilisés pour détecter le décollement tournant, permettant d'en tirer les caractéristiques de celui-ci (vitesse, nombre et amplitude des zones décollées). La technique de visualisation est très peu utilisée jusqu'à présent dans l'étude du décollement tournant dans les ventilateurs axiaux. Nous avons choisi cette méthode pour étudier le décollement tournant, puisque les images obtenues nous permettent une meilleure compréhension de la structure de l'écoulement étudié. Une étude bibliographique portant sur les travaux théoriques et expérimentaux dans le domaine de l'écoulement instationnaire concernant le décollement tournant dans les ventilateurs axiaux est présentée.
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Shanmugam, Dinesh Kumar, and dshanmugam@swin edu au. "Development of ice particle production system for ice jet process." Swinburne University of Technology. Industrial Research Institute Swinburne, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20050805.145343.
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This thesis presents a comprehensive study of the ice particle production process through experimentation and numerical methods using computational fluid dynamics (CFD) that can be used to produce ice particles with controlled temperature and hardness for use in ice jet (IJ) process for industrial applications. The analytical and numerical modeling for the heat exchanger system are developed that could predict the heat, mass and momentum exchange between the cold gas and water droplets. Further, the feasibility study of the deployment of ice particles produced from the ice jet system for possible cleaning and blasting applications are analyzed numerically. Although the use of Abrasive Water Jet (AWJ) technology in cutting, cleaning, machining and surface processing is a very successful industrial process, a considerable amount of secondary particle waste and contamination impingement by abrasive materials has been an important issue in AWJ process. Some alternate cryogenic jet methods involving vanishing abrasive materials, such as plain liquid nitrogen or carbon dioxide have been tried for these applications, but they also suffer from certain drawbacks relating to the quality, safety, process control and materials handling. The use of ice jet process involving minute ice particles has received relatively little attention in industrial applications. Some researches have concentrated on the studies of effects of Ice Jet outlet parameters of the nozzle and focus tube for machining soft and brittle materials. Most of the work in this area is qualitative and researchers have paid a cursory attention to the ice particles temperature and the efficiency of production of these particles. An extensive investigation to gain insight knowledge into the formulation of ice formation process parameters is required in arriving at a deeper understanding of the entire ice jet process for production application. Experimental investigations were focussed on the measurement of ice particle temperature, phase transitions, ice particle diameter, coalescence and hardness test. The change in ice particle diameter from the inlet conditions to the exit point of the heat exchanger wasinvestigated using the experimental results. These observations were extended to numerical analysis of temperature variations of ice particles at different planes inside the custom built heat exchanger. The numerical predictions were carried out with the aid of visualization studies and temperature measurement results from experiments. The numerical models were further analysed to find out the behaviour of ice particles in the transportation stage, the mixing chamber of the nozzle and focus tube. This was done to find out whether the methodology used in this research is feasible and if it can be used in applications such as cleaning, blasting, drilling and perhaps cutting. The results of the empirical studies show that ice particles of desired temperature and hardness could be produced successfully with the current novel design of the heat exchanger. At the optimum parameters, ice particles could be produced below -60�C, with hardness of particles comparable to gypsum (Moh�s hardness of 1.5 to 3). The visualization studies of the process assisted in observation of the phases of ice at various points along the heat exchanger. The results of numerical analysis were found to agree well with the experiments and were supported by the statistical model assessments. Numerical analyses also show the survival of ice particles at the nozzle exit even with high-pressure, high-velocity water/air mixture.
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Andersson, Anneli, and Felix Magnusson. "Understanding the design : A qualitative study of architecture and urban planning visualisation techniques in a public consultation setting." Thesis, Umeå universitet, Institutionen för informatik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-126135.
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Visualisation of proposed plans and designs can be done with a number of differenttechniques within the field of architecture and urban planning. But which visualisationtechnique is best suited when presenting a design proposal at a public consultation? Is therea breaking point where the user can form a general understanding of the proposed designdepending on the degree of fidelity? To seek answers to these questions a qualitative studywas conducted where five different visualisation techniques were tested on ten users toassess their understanding of a proposed design. Our findings show that there is not asingle best visualisation technique for public consultation. Based on our results thepreferred alternative would be a combination of several techniques. We could also see thatthe general understanding of a space increased until a certain degree, and after that adeeper more detail oriented understanding was achieved.
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Källman, Björn. "Investigation of detection methods for Berol Visco 388 : A study of visualisation reagents, spectroscopic and multivariate-coupled detection." Thesis, Umeå universitet, Kemiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-124413.
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Hingston, Phillip Anthony, and Hingston@bigpond com. "Animated proportional Venn diagrams: a study into their description, construction and business application." RMIT University. Economics, Finance and Marketing, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080213.111255.
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Anecdotal observation of the way in which data visualisation techniques are utilised to present relationships in data to audiences informed the author's view that data visualisation had not evolved to utilise the capabilities of ubiquitous business computer equipment. In an information rich but attention poor business environment, a search for a new tool was undertaken to supplement those techniques available to help audiences understand statistical relationships in presentation data. This search resulted in the development of a practical software tool based on animated Venn diagrams (Dvenn) that attempted to exploit the inherent human ability to perceive quantities visually, a faculty described herein as visual numeracy. The exploitation of this faculty is considered here to be a valuable aid for group understanding of business presentation data. The development of the tool was an essential part of the research that was undertaken and the resulting software forms a significant portion of this practise based research. The aim of the software development was to develop a readily accessible tool that could be utilised in a non-specialist business environment to better facilitate an honest shared meaning of numerical data between a presenter and their audience. The development of the tool progressed through a number of iterations and the software that accompanies this work is an important component that needs to be viewed in conjunction with the text. The test of the final version was undertaken with undergraduate University students in an attempt to validate the efficacy of the data visualisation technique. The test of the Dvenn software was made against the mature yardstick of scatter-plots. Interestingly, the correlations presented by scatter-plot were not as readily identified as would have been assumed, however, the results for the Dvenn tests were not supportive of the technique for widespread adoption. Nevertheless, further research into the best method of harnessing visual numeracy would seem to be justified.
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Nghifimule, Selma Ndilipomwene. "An analysis of the nature of visualisation objects in three Namibian grade 9 mathematics textbooks: a case study in Namibia." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/6334.
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Textbooks are a universal and central element of teaching and learning mathematics (Namibia. Ministry of Education [MoE], 2008). Steenpaß and Steinbring (2014) state that diagrams in mathematics textbooks are often used as Visualisation Objects (VOs) to enhance learning of mathematical concepts. VOs in textbooks are thus important teaching and learning tools (Fotakopoulou and Spiliotopoulou, 2008). This Namibian interpretive case study analysed the nature of VOs used in the three approved grade 9 Namibian mathematics textbooks namely: y=mx+c to success, Maths for Life 9 and Discover Mathematics 9. The VOs were analysed by using an analytical framework adapted from Fotakopoulou and Spiliotopoulou (2008). This analytic tool was specifically used to interrogate the following categories: the type of VOs, the roles of VOs, the relation of VOs to mathematical content, the relation of VOs to reality, and their properties. The 266 VOs under study were collected from the Algebra and Geometry chapters of each book. This study also included survey questionnaires with the 50 selected mathematics teachers, which sought their views and perceptions on the use of the identified VOs. In addition, the authors’ rationale in selecting the identified VOs used in their textbooks was sought through interviews. This research study is part of the “Visualisation in Namibia and Zambia” (VISNAMZA) project which seeks to research the effective use of visualisation processes in the mathematics classroom in Namibia and Zambia (Schäfer, 2015). It is hoped that this study contributes towards improving the quality of textbook evaluations, and design of suitable and more comprehensive assessment procedures in Namibia. It is also hoped that it creates a critical awareness of the roles of VOs in textbooks amongst teachers, inspiring them to help their learners interpret VOs effectively. It should also inspire potential authors to use suitable and appropriate VOs that enhance conceptual teaching and learning of mathematics. The study discovered that most of the VOs used in the selected textbooks align well with the mathematical content. The VOs can help make abstract ideas concrete, stimulate learning, simplify and clarify written texts. In addition, VOs can also be used as a tool for reasoning and an instrument for problem solving. The findings however also indicate that some of the VOs used are not self-explanatory; they are vague, unfamiliar and confusing, leading to misinterpretations by some learners. Another interesting finding was that some of the learners found it difficult to interpret VOs on their own without the help of the teacher.
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Bardoulet, Laëtitia Véronique. "Non-adiabatic capillary tubes in high efficiency household refrigerator: an experimental study." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/113170.
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El tubo capilar con intercambio de calor líquido-succión (CT-LSHX) es un componente ampliamente utilizado en refrigeradores domésticos. Trabajos recientes han indicado que la entrada del tubo capilar era bifásica, aunque condiciones subenfriadas estaban medidas a la salida del condensador.
El objetivo de esta tesis doctoral es examinar las condiciones reales a la entrada del tubo capilar de un refrigerador doméstico mediante el uso de un banco de pruebas innovador. Se instalaron tubos transparentes a la salida del condensador y a la entrada del tubo capilar con el fin de visualizar el flujo.
La campaña de visualización experimental revela que el flujo a la entrada del tubo capilar era bifásico a pesar de la medición de un cierto subenfriamiento, independientemente de la posición del filtro instalado a la entrada del capilar (horizontal o vertical), la dirección del flujo (hacia arriba o hacia abajo) y la carga de refrigerante. Este estudio demuestra también que el filtro no estaba actuando como un acumulador ya que el nivel de líquido del capilar siempre siguió la entrada del tubo capilar, independientemente de la longitud del tubo capilar dentro del filtro. Se plantearon dos hipótesis para explicar el fenómeno: una condición de no equilibrio del refrigerante y/o un desequilibrio entre el caudal másico del compresor y del capilar, es decir, el sistema estaría equipado con un capilar no bastante restrictivo en comparación con las necesidades del compresor.
El condensador original refrigerante-aire fue reemplazado por un condensador refrigerante-agua para evaluar, a partir del balance de calor en el condensador de agua, las condiciones del refrigerante a la salida del condensador y, por lo tanto, a la entrada del tubo capilar. Las mediciones indican un flujo bifásico no equilibrado compuesto de vapor y líquido subenfriados a la entrada del tubo capilar. Para verificar si la presencia de flujo bifásico se debía a un desequilibrio entre el caudal másico del compresor y del capilar, el diseño del banco de prueba se modificó utilizando un diámetro de tubo capilar más pequeño y aumentando la velocidad del compresor. Con esta nueva configuración, se alcanzó a llenar de líquido el filtro y, por lo tanto, tener condiciones exclusivamente líquidas a la entrada del tubo capilar.
Se realizó una comparación de prestaciones entre un flujo bifásico y un flujo únicamente líquido a la entrada del capilar. Los resultados revelan que el COP fue mayor cuando la entrada del capilar era sólo líquida.El tub capil·lar amb intercanvi de calor líquid-succió (CT-LSHX) és un component àmpliament utilitzat en refrigeradors domèstics. Treballs recents han indicat que l'entrada del tub capil·lar era bifàsica, encara que condicions sub-refredades estaven mesurades a l'eixida del condensador. L'objectiu d'aquesta tesi doctoral és examinar les condicions reals a l'entrada del tub capil·lar d'un refrigerador domèstic mitjançant l'ús d'un banc de proves innovador. Es van instal·lar tubs transparents a l'eixida del condensador i a l'entrada del tub capil·lar amb la finalitat de visualitzar el flux. La campanya de visualització experimental revela que el flux a l'entrada del tub capil·lar era bifàsic malgrat el mesurament d'un cert sub-refredament, independentment de la posició del filtre instal·lat a l'entrada del capil·lar (horitzontal o vertical), la direcció del flux (cap amunt o cap avall) i la càrrega de refrigerant. Aquest estudi demostra també que el filtre no estava actuant com un acumulador ja que el nivell de líquid del capil·lar sempre va seguir l'entrada del tub capil·lar, independentment de la longitud del tub capil·lar dins del filtre. Es van plantejar dues hipòtesis per a explicar el fenomen: una condició de no equilibri del refrigerant i/o un desequilibri entre el cabal màssic del compressor i del capil·lar, és a dir, el sistema estaria equipat amb un capil·lar no bastant restrictiu en comparació amb les necessitats del compressor. El condensador original refrigerant-aire va ser reemplaçat per un condensador refrigerant-aigua per a avaluar, a partir del balanç de calor en el condensador d'aigua, les condicions del refrigerant a l'eixida del condensador i, per tant, a l'entrada del tub capil·lar. Els mesuraments indiquen un flux bifàsic no equilibrat compost de vapor i líquid sub-refredats a l'entrada del tub capil·lar. Per a verificar si la presència de flux bifàsic es devia a un desequilibri entre el cabal màssic del compressor i del capil·lar, el disseny del banc de prova es va modificar utilitzant un diàmetre de tub capil·lar més xicotet i augmentant la velocitat del compressor. Amb aquesta nova configuració, es va aconseguir omplir de líquid el filtre i, per tant, tindre condicions exclusivament líquides a l'entrada del tub capil·lar. Es va realitzar una comparació de prestacions entre un flux bifàsic i un flux únicament líquid a l'entrada del capil·lar. Els resultats revelen que el COP va ser major quan l'entrada del capil·lar era només líquida.
Capillary tube with liquid-to-suction heat exchanger (CT-LSHX) is a component widely used in household refrigerators. Recent works have indicated that even when measuring subcooled conditions at the condenser outlet, the actual capillary tube inlet is two phase-flow. The aim of this PhD thesis is to examine the actual conditions at the capillary tube inlet of a household refrigerator by using an innovative test bench. Transparent tubes were set up at the condenser outlet and capillary tube inlet. The experimental visualisation campaign reveals that the capillary tube inlet was two-phase flow despite the measurement of a certain subcooling, regardless of the filter position (horizontal or vertical), flow direction (upward or downward) and refrigerant charge. This study also demonstrates that the filter was not acting as an accumulator since the liquid level of the capillary always followed the capillary tube entrance, regardless of the capillary tube length inside the filter. Two hypotheses were then posed to explain the phenomenon: a non-equilibrium condition of the refrigerant and/or an unbalanced matching between compressor and capillary tube, that is, the system would be equipped with a capillary tube with a notably large expansion capacity compared to the needs of the compressor. The original refrigerant-to-air condenser was replaced by a refrigerant-to-water condenser to assess, from the heat balance at the water condenser, the refrigerant conditions at the condenser outlet and therefore, at the capillary tube inlet. Measurements indicate a non-equilibrium two-phase flow composed of subcooled vapour and liquid at the capillary tube inlet. To verify if the presence of two-phase flow was due to unbalanced matching between the capillary tube and compressor, the test bench design was modified by using a smaller capillary tube diameter and increasing compressor speed. Fully liquid conditions at the capillary tube inlet were reached with this new configuration. A performance analysis comparison between a capillary tube inlet composed of vapour and liquid and a capillary tube inlet composed of only liquid was also performed. Results reveal that COP were higher in cases of fully liquid conditions at the capillary tube inlet.
Bardoulet, LV. (2018). Non-adiabatic capillary tubes in high efficiency household refrigerator: an experimental study [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113170
TESIS
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Daniel, Marc. "Modélisation de courbes et surfaces par des b-splines. : Application à la conception et à la visualisation de formes." Nantes, 1989. http://www.theses.fr/1989NANT2013.
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Présentation des b-splines et de quelques propriétés de base. Comparaison détaillée des algorithmes de manipulation de courbes et surfaces b-splines existants tant du point de vue du nombre d'opérations, que du point de vue fondamental de leur stabilité et des problèmes numériques induits. Le problème des interventions est ensuite abordé avec la proposition d'un ensemble d'algorithmes et la mise en évidence des nombreuses difficultés techniques intéressantes au problème.
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Schafer, Marc. "The impact of learners' spatial capacity and world views on their spatial conceptualisation : a case study." Curtin University of Technology, Science and Mathematics Education Centre, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=13863.
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This multi-sited case study aims to explore spatial capacity through pen-and-paper and hands-on activity tests, and explore world view perceptions of space in an attempt to show that spatial conceptualisation is a rich and complex blend of spatial capacity and world view. This study is oriented in a interpretive-naturalistic paradigm and characterised by multi-dimensional quantitative and qualitative methods. The research, set in five secondary schools in the Eastern Cape, was carried out with 32 Grade 11 learners and was designed around seven stages. This study attempts to understand spatial conceptualisation by recognising that all learners have epistemological macrostructures (world views) that shape their perceptions of the world in general and of space in particular. The main contention of this study is that spatial conceptualisation cannot be understood in isolation, through studying achievements on traditional pen-and-paper tests only. A comprehensive understanding of an individual's spatial conceptualisation involves the recognition of hands-on skills and world views as well. Spatial capacity, defined here in terms of spatial visualisation and orientation constructs, was explored through a pen-and-paper and a hands-on activity test. The results show only a weak to moderate correlation between the two tests, suggesting that performance in a traditional pen-and-paper test was not necessarily a good predictor for performance in a hands-on activity-based test. The investigation of world views was underpinned by a logico-structuralist process centred in conversations around nine bi-polar themes. Through a process of content- and meta- analyses involving the participation of a validation team, world-view profiles were established.In terms of the applied pen-and-paper test which explored spatial capacity, this study confirms males' dominance in all spatial tasks, particularly in three-dimensional problems. This was also found to be true for learners from the participating rural school and for those from disadvantaged socio-economic backgrounds. In the hands-on activity test, however, the study revealed no observable gender difference in favour of the males, except for items that were characterised by the spatial orientation construct. Both the participating rural and township schools performed poorly in items characterized by the spatial visualisation and orientation construct compared to the other participating schools. Although participants from the rural and township schools found it difficult to articulate their world views in depth, the world-view perspectives of space of this sample reveal rich and complex profiles that are similar across all the schools. Despite leaning towards a Newtonian division of absolute and relative space and containing strong religious elements, this sample generally views space as mysterious, infinite and somewhat obscure. It often refers to space in Kantian ideas and related space in terms of subjective feelings. Females in particular, refer to their own `space bubble', for example. Out of the world-view profile analysis, a meta-analysis was conducted which explored thinking skills in terms of capacity to abstract, to be insightful, deal with complex issues, engage critically, and be imaginative.
This reveals that for this case, females were rated on a higher level than their male counterparts for their capacity to abstract and be complex (the capacity to identify related parts and to deal with composites), whereas males rated higher for showing insight, being imaginative, and being critical. Although there appear to be high correlations between the various tests, meta-levels and school performance for some of the participants, the same cannot be said for the sample as a whole. The world-view aspect of this study reveals a rich, often complex, understanding of space, strengthening the notion that world views are integral to a learner's cognition process.
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Marrero, Santiago Javier. "Expérimental study of lean aeronautical ignition : impact of critical parameters on the mechanisms acting along the different ignition phases." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR03/document.
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La certification des moteurs aéronautiques impose des fortes réductions des émissions polluantes. Une des solutions adoptées par les constructeurs est d'introduire la combustion pauvre dans les nouvelles chambres. Cette configuration pose des problèmes de stabilité de flamme et de ré-allumage en altitude. Le ré-allumage des moteurs doit être garanti et il y a une nécessité réelle de mieux comprendre les interactions complexes et multi-physiques guidant ce processus. Cette étude expérimentale vise les différentes phases de l'allumage aéronautique dans deux chambres swirlées, confinées diphasiques. Un foyer mono-injecteur permet d'analyser le développement du noyau de flamme dans ses premiers instants et de décrire comment les interactions avec l'écoulement local peuvent conduire à une réussite d'allumage ou à une ratée, via différents mécanismes. Une chambre multi-injecteur est dédiée à analyser la propagation de la flamme entre injecteurs pour différents espacements et carburantsJet engine certification undergoes more and more stringent controls that impose a strong reduction of pollutant emissions. As a response, designs move towards lean combustion, which raises difficulties relative to combustion stability and re-ignition capabilities in high altitude. The use of liquid fuels in real chambers introduces new variables into the ignition process, which involves complex simultaneous multi-physical interactions. The present experimental investigation addresses different phases of aeronautical ignition in two different confined, swirled, spray jet chambers. A single-injector facility is used to study the initial flame kernel development and interaction with the flow leading to successful ignition or misfire, following different mechanisms. A multi-injector facility enables the investigation of flame propagation between injectors, which is also governed by the local flow. Here, inter-injector distances are varied and fuels of different volatilities are tested
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Thompson, David John. "Large-Scale Display Interaction Techniques to Support Face-to-Face Collaboration." Thesis, University of Canterbury. Computer Science and Software Engineering, 2006. http://hdl.handle.net/10092/1192.
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This research details the development of a large-scale, computer vision-based touch screen capable of supporting a large number of simultaneous hand interactions. The system features a novel lightweight multi-point tracking algorithm to improve real-time responsiveness. This system was trialled for six months in an exhibition installation at World Expo 2005 in Aichi, Japan, providing a robust, fault-tolerant interface. A pilot study was then conducted to directly compare the system against other, more established input methods (a single-touch case, a two-mouse case and a physical prototype) to determine the effectiveness and affordances of the multi-touch technology for arranging information on a large-scale wall space in a paired collaborative task. To assist in this study, a separate visualisation and interaction classification tool was developed, allowing the replay of XML log data in real time to assist in the video analysis required for observation and hypothesis testing.
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Lebret, Alain. "Study on the cerebrospinal fluid volumes." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1088/document.
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Cette thèse contribue au manque d'outils informatiques pour l'analyse d'images médicales et le diagnostic, en particulier en ce qui concerne l'étude des volumes du liquide cérébrospinal. La première partie concerne la mesure du volume des compartiments du liquide à partir d'images corps entier, pour une population composée d'adultes sains et de patients atteints d'hydrocéphalie. Les images sont obtenues à partir d'une séquence IRM développée récemment et mettant en évidence le liquide par rapport aux structures voisines, de manière à faciliter sa segmentation. Nous proposons une méthode automatique de segmentation et de séparation des volumes permettant une quantification efficace et reproductible. Le ratio des volumes des compartiments sous-arachnoïdien et ventriculaire est constant chez l'adulte sain, ce qui permet de conserver une pression intracrânienne stable. En revanche, il diminue et varie fortement chez les patients atteints d'hydrocéphalie. Ce ratio fournit un index physiologique fiable pour l'aide au diagnostic de la maladie. La seconde partie de la thèse est consacrée à l'analyse de la distribution du liquide dans le compartiment sous-arachnoïdien intracrânial supérieur. Il convient de souligner que ce compartiment, particulièrement complexe d'un point de vue anatomique, demeure peu étudié. Nous proposons deux techniques de visualisation de la distribution du volume liquidien contenu dans ce compartiment, qui produisent des images bidimensionnelles à partir des images d'origine. Ces images permettent de caractériser la distribution du volume liquidien et de son réseau, tout en distinguant les adultes sains des patients souffrant d'hydrocéphalieThis work aims to contribute to the lack of computational methods for medical image analysis and diagnosis about the study of cerebrospinal fluid volumes. In the first part, we focus on the volume assessment of the fluid spaces, from whole body images, in a population consisting of healthy adults and hydrocephalus patients. To help segmentation, these images, obtained from a recent "tissue-specific" magnetic resonance imaging sequence, highlight cerebrospinal fluid unlike its neigh borhood structures. We propose automatic segmentation and separation methods of the different spaces, which allow efficient and reproducible quantification. We show that the ratio of the total subarachnoid space volume to the ventricular one is a proportionality constant for healthy adults, to support a stable intracranial pressure. However, this ratio decreases and varies significantly among patients suffering from hydrocephalus. This ratio provides a reliable physiological index to help in the diagnosis of hydrocephalus. The second part of this work is dedicated to the fluid volume distribution analysis within the superior cortical subarachnoid space. Anatomical complexity of this space induces that it remains poorly studied. We propose two complementary methods to visualize the fluid volume distribution, and which both produce two-dimensional images from the original ones. These images, called relief maps, are used to characterize respectively, the fluid volume distribution and the fluid network, to classify healthy adults and patients with hydrocephalus, and to perform patient monitoring before and after surgery
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Ravichandran, Tarunika. "Value-Centric Behaviour Change with Data Visualisation : Case study for visualising data on grocery consumption to bring about value-centric purchasing patterns for retail supermarket consumers." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279429.
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Dietary choices are a leading global cause of mortality and environmental degradation that threaten the attainability of the UN's Sustainable Development Goals and the Paris Climate Agreement [1]. It thus becomes important to find ways to reduce its environmental impact and facilitate healthy consumption patterns. Humans use values as guiding standards, in making judgements [4] which in turn contribute to product choices in the grocery shopping process. The focus of this thesis is to help consumers of large retail supermarkets to make informed choices, aligned with their personal goals, to develop a value-centric purchasing habit with the ultimate aim of lowering the impact on the environment and the negative effects on the health of the consumers. By using the design thinking process along with the behaviour change wheel framework it was possible to empathize with and understand the target user group to identify design features for the mobile application suggested by this thesis. To achieve value centric purchasing habits, the most promising observation was to provide all the necessary information at the grocery planning phase. This would enable informed-choice-making, in line with the personal goals of the consumers while making grocery lists. It is assumed in this thesis that consumers purchase the same brand and product added to their shopping list. Along with the information on products, visualisations of the target shopping patterns against their actual shopping patterns are presented to the user. This would in turn help consumers make the right decision by providing an overview of how their product choices influence in reaching their target goals. Based on commonly used and easily understandable visualisation methods, a radar chart and line chart depicting their past purchase patterns and goals were evaluated against each other with usability tests. The visualisations and interactions were supplemented with clear legends to ensure that the consumers perceived what was intended. Use of animations on these visualisations was suggested to increase the understanding and effectiveness in the communication of its data. While both these methods had their own strengths and weaknesses the radar chart was better received and was thus suggested for use in the development of the application.Kostval ar en viktig orsak till dödlighet och miljöförstöring på global nivå, vilket hotar möjligheterna att uppnå både FN:s utvecklingsmål kring hållbarhet och Parisavtalet [1]. Det är därför viktigt att finna satt att minska kostens miljöpåverkan och underlätta mer hälsosamma konsumtionsmönster. Människor använder sina egna värderingar nar de gör bedömningar [4] som i sin tur avgör vilka produkter de väljer i dagligvaruhandeln. Fokus for detta examensarbete ar att hjälpa konsumenter i dagligvarubutiker att fatta välgrundade val, i linje med deras personliga mal och värderingar, med det slutliga malet att minska miljöpåverkan och negativa hälsoeffekter for konsumenterna. Genom att använda en "design thinking"-process tillsammans med beteendeförändringsramverket "behaviour change wheel" var det i examensarbetet möjligt att empatisera med och första målgruppen, for att identifiera designfunktioner for den mobilapplikation som föreslås i detta examensarbete. For att uppnå vardecentriska köpvanor var den mest lovande observationen att tillhandahålla all nödvändig information i livsmedelsplaneringsfasen. Detta skulle möjliggöra informerade valmöjligheter, i linje med konsumenternas personliga mal samtidigt som de gör inköpslistor. Det antas i detta examensarbete att konsumenter köper samma märke och produkt som laggs till i deras inköpslista. Tillsammans med informationen om produkter presenteras visualiseringar av malen for inköp mot användarnas faktiska inköp. Detta kan i sin tur hjälpa konsumenterna att fatta ratt inköpsbeslut genom att ge en översikt over hur deras produktval påverkar nar de nar sina mal. Baserat på vanligt använda och lättförståeliga visualiseringsmetoder utvärderades ett radarkarta och ett linjediagram som visar användarnas tidigare inköpsmönster och mal, mot varandra med användbarhetstester. Visualiseringarna och interaktionerna kompletterades med tydliga diagramförklaringar for att säkerställa att konsumenterna uppfattade vad som var avsett. Användning av animationer på dessa visualiseringar föreslogs for att oka förståelsen och effektiviteten i kommunikationen av dess data. Medan bada dessa metoder hade sina egna styrkor och svagheter mottogs radarkartan bättre och föreslås därför for användning i utvecklingen av applikationen.
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Alharbi, Saad T. "Graphical and Non-speech Sound Metaphors in Email Browsing: An Empirical Approach. A Usability Based Study Investigating the Role of Incorporating Visual and Non-Speech Sound Metaphors to Communicate Email Data and Threads." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4244.
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This thesis investigates the effect of incorporating various information visualisation techniques and non-speech sounds (i.e. auditory icons and earcons) in email browsing. This empirical work consisted of three experimental phases. The first experimental phase aimed at finding out the most usable visualisation techniques for presenting email information. This experiment involved the development of two experimental email visualisation approaches which were called LinearVis and MatrixVis. These approaches visualised email messages based on a dateline together with various types of email information such as the time and the senders. The findings of this experiment were used as a basis for the development of a further email visualisation approach which was called LinearVis II. This novel approach presented email data based on multi-coordinated views. The usability of messages retrieval in this approach was investigated and compared to a typical email client in the second experimental phase. Users were required to retrieve email messages in the two experiments with the provided relevant information such as the subject, status and priority. The third experimental phase aimed at exploring the usability of retrieving email messages by using other type of email data, particularly email threads. This experiment investigated the synergic use of graphical representations with non-speech sounds (Multimodal Metaphors), graphical representations and textual display to present email threads and to communicate contextual information about email threads. The findings of this empirical study demonstrated that there is a high potential for using information visualisation techniques and non-speech sounds (i.e. auditory icons and earcons) to improve the usability of email message retrieval. Furthermore, the thesis concludes with a set of empirically derived guidelines for the use of information visualisation techniques and non-speech sound to improve email browsing.Taibah University in Medina and the Ministry of Higher Education in Saudi Arabia.
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Digregorio, Giuseppe. "Real - time data and BIM: automated protocol for management and visualisation of data in real time : A case study in the "Teaching House" of the KTH campus." Thesis, KTH, Byggnadsmaterial, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-294265.
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Nowadays BIM and real-time data are becoming a central topic for the AECO (Architecture, Engineering, Construction and Operations) industry, they represent new powerful tools for the design and management of facilities.Building monitoring and real-time data can represent a solution to many important challenges like energy efficiency, indoor climate quality and cost management. Although it is clear the importance of data for a correct use of BIM technology and its potentiality, in literature, are not so common examples of complete workflows for a complete management of data from the input phase to the output one.The scope of the study is to design a protocol for entering, managing and exporting real-time data using Revit and Dynamo where the customers have a central role during the input phase and a dedicated mode for data display including a desktop version and an augmented reality one for a more immersive experience.In order to show the real potentiality of the project, the protocol has been utilised for the calculation of thermal comfort parameters of the “Teaching House” situated in KTH campus. All data entered from the students into a form online, via QR-code, have been inserted into Dynamo in order to calculate the desired parameters values which are successively stored into a database for further analysis, everything automatically.Numera blir BIM och realtidsdata ett centralt ämne för AECO (Architecture, Engineering, Construction and Operations) industrin, de representerar nya kraftfulla verktyg för design och hantering av anläggningar.Byggnadsövervakning och realtidsdata kan vara en lösning på många viktiga utmaningar som energieffektivitet, inomhusklimatkvalitet och kostnadshantering. Även om det är tydligt är betydelsen av data för en korrekt användning av BIM-teknik och dess potential i litteraturen inte så vanliga exempel på fullständiga arbetsflöden för en fullständig hantering av data från inmatningsfasen till den utgående.Studiens omfattning är att utforma ett protokoll för inmatning, hantering och export av realtidsdata med Revit och Dynamo där kunderna har en central roll under inmatningsfasen och ett dedikerat läge för datavisning inklusive en stationär version och en förstärkt verklighet en för en mer uppslukande upplevelse.För att visa projektets verkliga potential har protokollet använts för beräkning av termiska komfortparametrar för ”Teaching House” beläget på KTH campus. Alla data som matats in från eleverna i ett formulär online, via QR-kod, har införts i Dynamo för att beräkna önskade parametervärden som successivt lagras i en databas för vidare analys, allt automatiskt.
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Ricknäs, Daniel, and Frida Stam. "Visual User Interface for PDAs." Thesis, Linköping University, Department of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1994.
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This report is a part of a diploma work, conducted as a part of a Master of Science degree. The diploma work consists of a preliminary study, two case studies, a user study, a paper and this report. It was created at the Linköping University for the department of Science and Technology, in cooperation with Unilever Research in the UK, and partly with the EC founded project, Smartdoc IST-2000-28137.
Hand-held, mobile devices like Personal Digital Assistances (PDAs) are becoming increasingly popular in today’s wireless world. While trying to pack all the possible information into a small window, a nightmarish scenario is created for the interface designer to deal with. The goal for this project was to investigate different Visual User Interfaces (VUIs)on PDAs, and how to apply desktop interaction techniques to PDAs.
A VUI model based on Zooming User Interface (ZUI) techniques, to adapt two complete different visualisation application areas; on-line brand-based shopping and flood warning system for PDAs, is presented. The on-line brand- based shopping was evaluated in a benchmark usability study comparing it to traditional PC based on-line shopping.
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Alharbi, Saad Talal. "Graphical and non-speech sound metaphors in email browsing : an empirical approach : a usability based study investigating the role of incorporating visual and non-speech sound metaphors to communicate email data and threads." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4244.
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This thesis investigates the effect of incorporating various information visualisation techniques and non-speech sounds (i.e. auditory icons and earcons) in email browsing. This empirical work consisted of three experimental phases. The first experimental phase aimed at finding out the most usable visualisation techniques for presenting email information. This experiment involved the development of two experimental email visualisation approaches which were called LinearVis and MatrixVis. These approaches visualised email messages based on a dateline together with various types of email information such as the time and the senders. The findings of this experiment were used as a basis for the development of a further email visualisation approach which was called LinearVis II. This novel approach presented email data based on multi-coordinated views. The usability of messages retrieval in this approach was investigated and compared to a typical email client in the second experimental phase. Users were required to retrieve email messages in the two experiments with the provided relevant information such as the subject, status and priority. The third experimental phase aimed at exploring the usability of retrieving email messages by using other type of email data, particularly email threads. This experiment investigated the synergic use of graphical representations with non-speech sounds (Multimodal Metaphors), graphical representations and textual display to present email threads and to communicate contextual information about email threads. The findings of this empirical study demonstrated that there is a high potential for using information visualisation techniques and non-speech sounds (i.e. auditory icons and earcons) to improve the usability of email message retrieval. Furthermore, the thesis concludes with a set of empirically derived guidelines for the use of information visualisation techniques and non-speech sound to improve email browsing.
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Bourgeois, Magali. "Analyse des instabilités de sillages en écoulement cisaille." Toulouse 3, 1986. http://www.theses.fr/1986TOU30192.
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Etude expérimentale en canal hydrodynamique vertical de la zone de mélange qui se développe entre deux courants de vitesses différentes séparés par une plaque épaisse. Mise au point de techniques de visualisation (trajectographie, extraction de contours); développement de logiciels de traitement
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Mwiikeni, Eramus. "An analysis of how geogebra can be used as a visualisation tool by selected teachers to develop conceptual understanding of the properties of geometric shapes in grade 9 learners: a case study in Namibia." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/6989.
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According to Rosken & Rolka (2006), learning mathematics through visualisations can be a powerful tool to explore mathematical problems and give meaning to mathematical concepts and relationships between them. “Visualisation can reduce the complexity of mathematical problems when dealing with a multitude of information” (p.458). This case study focused on using GeoGebra as a visualisation tool to teach angle properties in Grade 9 geometry. This study set out to analyse how GeoGebra visualisations can be used by selected teachers to teach for conceptual understanding. The research is based on a constructivist view of learning and is oriented within an interpretive paradigm. The methodology used is a qualitative case study. The study was conducted in one school and involved 3 mathematics teachers who were purposefully selected because they showed willingness to use technology in their teaching. I used classroom observations and interviews to collect the data. The study identified a number of factors from the participants that related to using GeoGebra in teaching for conceptual understanding. These include the effective use of dynamic visuals to build on prior knowledge, using multiple representations through image generation and image transformation to make connections and using visuals to justify mathematics ideas. The results from this study indicated that GeoGebra can indeed be used effectively as a teaching tool to teach for conceptual understanding in mathematics.
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Guédron, Sylvain. "Etude de l'instabilite du panache au-dessus d'un tube chauffe dispose horizontalement en piscine." Nantes, 1988. http://www.theses.fr/1988NANT2038.
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On montre que le phenomene de "balancement" periodique du panache n'est qu'apparent et qu'il est du a une evolution au cours du temps de la direction de la vitesse au point de decollement du panache. Analyse qualitative et quantitative des mesures de temperature et des visualisations mettant en evidence une onde transversale se propageant le long du tube et suivant laquelle le panache se deforme. Determination des parametres influencant le "balancement" du panache
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Aloui, Fethi. "Étude des écoulements monophasiques et diphasiques dans les élargissements brusques axisymétrique et bidimensionnel." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL055N.
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Ce travail traite d'une étude théorique et expérimentale sur les écoulements monophasiques et diphasiques (à bulles) dans les élargissements brusques. Deux configurations d'élargissement ont été étudiées: l'une est axisymétrique verticale et l'autre bidimensionnelle horizontale. À travers ces singularités, une approche globale qui détermine la chute de pression singulière a été développée, et une étude expérimentale a été réalisée sur la dynamique des phases liquide et gazeuse. Dans l'élargissement brusque vertical axisymétrique, l'écoulement est symétrique. Les grandeurs mesurées concernent la vitesse axiale du liquide en écoulement monophasique et le taux de vide, la vitesse axiale des bulles et la granulométrie des bulles en écoulement diphasique. Au voisinage immédiat de la singularité, ces résultats expérimentaux locaux ont permis de donner la tendance générale de la réorganisation de l'écoulement monophasique et diphasique. Pour l'élargissement brusque bidimensionnel horizontal, la visualisation de l'écoulement a joué un rôle important dans la compréhension des phénomènes de transition d'un écoulement complètement dissymétrique vers un écoulement symétrique. En écoulement monophasique, l'étude expérimentale a concerné la pression et la vitesse axiale du liquide mesurée par un film chaud. Dans cet écoulement, la dissymétrie de l'écoulement n'a pas de cote préférentiel pour son orientation. En écoulement diphasique, la transition vers un écoulement symétrique se fait par augmentation progressive du débit de gaz pour un débit de liquide fixe. Les résultats expérimentaux relatifs à ce type de singularité en écoulement à bulles concernent le taux de vide, les vitesses axiales de chacune des phases et la granulométrie des bulles. Ces grandeurs nous ont permis de décrire d'une part les structures locales de l'écoulement diphasique et d'autre part de vérifier ce qui a été obtenu par la visualisation
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Kangwa, Lemmy. "An investigation of how Visual Technology for the Autonomous Learning of Mathematics (VITALmaths) video clips on mobile phones can be used by student teachers as a visualisation tool in the teaching of Number Sense: a case study." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/6930.
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Visualisation is increasingly being recognised as having a significant role in the learning of mathematics especially when students are solving mathematical problems (Thornton, 2001). It is argued that visualisation is a powerful tool for learners to construct mental and physical representations that correctly mirror mathematical relationships and concepts. To gain a thorough understanding of the scope of visualisation, three Visual Technology for Autonomous Learning of Mathematics (VITALmaths) (www.vitalmaths.com) video clips were uploaded on mobile phones of each of the eleven participating student teachers who used them in their teaching practice. This is in cognisance of the educational potential offered by mobile phones and their current pervasiveness in the daily lives of both teachers and learners in Zambia (Zambia. Ministry of Education [M.O.E], 2013]). This study sought to investigate how VITALmaths video clips on mobile phones could be used by student teachers as a visualisation tool in the teaching of Number Sense. The videos of the lessons formed the core of my analysis. The study was conducted at four primary schools by eleven student teachers of a public university in Zambia. The study is framed as a case study and is grounded within the interpretive paradigm. The findings revealed that the student teachers’ use of the video clips in the classrooms for teaching was generally approached from two perspectives: at the beginning of the lesson or at the end. The videos were used at the beginning of the lesson as a means to introduce a topic or an idea, and at the end of the lesson to consolidate what was taught. The videos were also used to enhance the conceptual understanding of Number Sense. The findings also revealed that students encountered both enabling and constraining factors in their use of mobile phones to teach number sense. The overall findings revealed that, if well utilised, mobile phones as visualisation tools had the potential to enhance the teaching of Mathematics in general and Number Sense in particular, and therefore teachers should be encouraged to use them in their teaching.
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Médoc, Nicolas. "A visual analytics approach for multi-resolution and multi-model analysis of text corpora : application to investigative journalism." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB042/document.
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À mesure que la production de textes numériques croît exponentiellement, un besoin grandissant d’analyser des corpus de textes se manifeste dans beaucoup de domaines d’application, tant ces corpus constituent des sources inépuisables d’information et de connaissance partagées. Ainsi proposons-nous dans cette thèse une nouvelle approche de visualisation analytique pour l’analyse de corpus textuels, mise en œuvre pour les besoins spécifiques du journalisme d’investigation. Motivées par les problèmes et les tâches identifiés avec une journaliste d’investigation professionnelle, les visualisations et les interactions ont été conçues suivant une méthodologie centrée utilisateur, impliquant l’utilisateur durant tout le processus de développement. En l’occurrence, les journalistes d’investigation formulent des hypothèses, explorent leur sujet d’investigation sous tous ses angles, à la recherche de sources multiples étayant leurs hypothèses de travail. La réalisation de ces tâches, très fastidieuse lorsque les corpus sont volumineux, requiert l’usage de logiciels de visualisation analytique se confrontant aux problématiques de recherche abordées dans cette thèse. D’abord, la difficulté de donner du sens à un corpus textuel vient de sa nature non structurée. Nous avons donc recours au modèle vectoriel et son lien étroit avec l’hypothèse distributionnelle, ainsi qu’aux algorithmes qui l’exploitent pour révéler la structure sémantique latente du corpus. Les modèles de sujets et les algorithmes de biclustering sont efficaces pour l’extraction de sujets de haut niveau. Ces derniers correspondent à des groupes de documents concernant des sujets similaires, chacun représenté par un ensemble de termes extraits des contenus textuels. Une telle structuration par sujet permet notamment de résumer un corpus et de faciliter son exploration. Nous proposons une nouvelle visualisation, une carte pondérée des sujets, qui dresse une vue d’ensemble des sujets de haut niveau. Elle permet d’une part d’interpréter rapidement les contenus grâce à de multiples nuages de mots, et d’autre part, d’apprécier les propriétés des sujets telles que leur taille relative et leur proximité sémantique. Bien que l’exploration des sujets de haut niveau aide à localiser des sujets d’intérêt ainsi que leur voisinage, l’identification de faits précis, de points de vue ou d’angles d’analyse, en lien avec un événement ou une histoire, nécessite un niveau de structuration plus fin pour représenter des variantes de sujet. Cette structure imbriquée révélée par Bimax, une méthode de biclustering basée sur des motifs avec chevauchement, capture au sein des biclusters les co-occurrences de termes partagés par des sous-ensembles de documents pouvant dévoiler des faits, des points de vue ou des angles associés à des événements ou des histoires communes. Cette thèse aborde les problèmes de visualisation de biclusters avec chevauchement en organisant les biclusters terme-document en une hiérarchie qui limite la redondance des termes et met en exergue les parties communes et distinctives des biclusters. Nous avons évalué l’utilité de notre logiciel d’abord par un scénario d’utilisation doublé d’une évaluation qualitative avec une journaliste d’investigation. En outre, les motifs de co-occurrence des variantes de sujet révélées par Bima. sont déterminés par la structure de sujet englobante fournie par une méthode d’extraction de sujet. Cependant, la communauté a peu de recul quant au choix de la méthode et son impact sur l’exploration et l’interprétation des sujets et de ses variantes. Ainsi nous avons conduit une expérience computationnelle et une expérience utilisateur contrôlée afin de comparer deux méthodes d’extraction de sujet. D’un côté Coclu. est une méthode de biclustering disjointe, et de l’autre, hirarchical Latent Dirichlet Allocation (hLDA) est un modèle de sujet probabiliste dont les distributions de probabilité forment une structure de bicluster avec chevauchement. (...)As the production of digital texts grows exponentially, a greater need to analyze text corpora arises in various domains of application, insofar as they constitute inexhaustible sources of shared information and knowledge. We therefore propose in this thesis a novel visual analytics approach for the analysis of text corpora, implemented for the real and concrete needs of investigative journalism. Motivated by the problems and tasks identified with a professional investigative journalist, visualizations and interactions are designed through a user-centered methodology involving the user during the whole development process. Specifically, investigative journalists formulate hypotheses and explore exhaustively the field under investigation in order to multiply sources showing pieces of evidence related to their working hypothesis. Carrying out such tasks in a large corpus is however a daunting endeavor and requires visual analytics software addressing several challenging research issues covered in this thesis. First, the difficulty to make sense of a large text corpus lies in its unstructured nature. We resort to the Vector Space Model (VSM) and its strong relationship with the distributional hypothesis, leveraged by multiple text mining algorithms, to discover the latent semantic structure of the corpus. Topic models and biclustering methods are recognized to be well suited to the extraction of coarse-grained topics, i.e. groups of documents concerning similar topics, each one represented by a set of terms extracted from textual contents. We provide a new Weighted Topic Map visualization that conveys a broad overview of coarse-grained topics by allowing quick interpretation of contents through multiple tag clouds while depicting the topical structure such as the relative importance of topics and their semantic similarity. Although the exploration of the coarse-grained topics helps locate topic of interest and its neighborhood, the identification of specific facts, viewpoints or angles related to events or stories requires finer level of structuration to represent topic variants. This nested structure, revealed by Bimax, a pattern-based overlapping biclustering algorithm, captures in biclusters the co-occurrences of terms shared by multiple documents and can disclose facts, viewpoints or angles related to events or stories. This thesis tackles issues related to the visualization of a large amount of overlapping biclusters by organizing term-document biclusters in a hierarchy that limits term redundancy and conveys their commonality and specificities. We evaluated the utility of our software through a usage scenario and a qualitative evaluation with an investigative journalist. In addition, the co-occurrence patterns of topic variants revealed by Bima. are determined by the enclosing topical structure supplied by the coarse-grained topic extraction method which is run beforehand. Nonetheless, little guidance is found regarding the choice of the latter method and its impact on the exploration and comprehension of topics and topic variants. Therefore we conducted both a numerical experiment and a controlled user experiment to compare two topic extraction methods, namely Coclus, a disjoint biclustering method, and hierarchical Latent Dirichlet Allocation (hLDA), an overlapping probabilistic topic model. The theoretical foundation of both methods is systematically analyzed by relating them to the distributional hypothesis. The numerical experiment provides statistical evidence of the difference between the resulting topical structure of both methods. The controlled experiment shows their impact on the comprehension of topic and topic variants, from analyst perspective. (...)
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Ohmi, Kazuo. "Etude de la formation du sillage autour d'un profil en oscillation." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37608517d.
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Hassan, Abdul Hakim. "Etude expérimentale et numérique du comportement local et global d'une interface sol granulaire-structure." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10228.
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Une nouvelle approche est utilisee afin d'aborder le comportement des interfaces sol granulaire-structure ; il s'agit d'une etude experimentale et numerique du comportement mecanique d'interface a l'echelle locale, ainsi que de la liaison entre les aspects local et global du comportement d'interface sol granulaire-structure. Cette etude a ete menee experimentalement au moyen d'un appareil de cisaillement direct plan asservi muni d'un hublot de visualisation laterale, et numeriquement grace au modele lmgc permettant de simuler le comportement mecanique des materiaux granulaires. La mise au point d'une nouvelle technique de visualisation (images video analysees grace a un pointeur de coordonnees) a permis d'analyser le comportement local dans la zone d'interface sol-structure, a partir du mouvement individuel des particules constituant l'echantillon de sable utilise. Dans un premier temps, nous proposons une description du dispositif experimental et de la technique de visualisation utilises afin de realiser les experiences inscrites dans le cadre de ce travail. Les resultats experimentaux relatifs aux comportements local et global, leur interpretation et la validation de la technique de visualisation utilisee pour examiner le comportement microscopique de l'interface sol-structure sont presentes en second lieu. La simulation numerique du comportement micro-macromecanique d'interface assemblage granulaire-structure, exposee a la fin de ce memoire, comprend une description du logiciel lmgc utilise, une presentation des resultats de simulation et une comparaison qualitative entre les resultats de simulation et ceux de l'experience
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Pocheau, Alain. "Structures spatiales et turbulence de phase en convection de rayleigh-benard." Paris 7, 1987. http://www.theses.fr/1987PA077063.
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On analyse la transition sur deux decades de nombre de prandtl, du regime de selection de nombre de d'onde a celui de turbulence de phase. On determine le role des defauts de structure. On identifie la presence d'ecoulements de derive dont on demontre l'importance envers la formation des contraintes. Cet effet est analyse par un formalisme d'invariance de jauge. Par visualisation de la convection en phase gazeuse on caracterise les mecanismes de la turbulence de phase
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Richard, Gontran. "Étude expérimentale et optimisation fonctionnelle des installations de séparation électrostatique de mélanges de matériaux granulaires." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2260/document.
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La démarche expérimentale menée dans cette thèse CIFRE a eu comme objectif l’étude de la faisabilité de la séparation électrostatique d’une large gamme de mélanges de matériaux granulaires issus de déchets d’équipements électriques et électroniques (conducteur – isolant, conducteur – conducteur et isolant – isolant). Trois mécanismes physiques de charge électriques ont été mis en oeuvre : l’induction électrostatique, la décharge couronne et l’effet triboélectrique. Un dispositif de charge de laboratoire et deux séparateurs électrostatiques industriels ont été conçus et réalisés. Le dispositif de charge à cylindre(s) tournant(s) permet la charge triboélectrique de matériaux plastiques. Le prototype de séparateur industriel a d’abord été réalisé pour le traitement de mélanges granulaires conducteur – isolant puis a été adapté à la séparation isolant – isolant. Les trois mécanismes de charge peuvent y être utilisés. Ce prototype a permis la fabrication du premier séparateur électrostatique de série de la société CITF dédié à la séparation de déchets de câbles électriques. Des mesures de charge et de masse ainsi que des simulations et visualisations des trajectoires des particules par caméra rapide ont facilité l’analyse des phénomènes. La méthode des plans d’expérience a permis d’identifier les facteurs influents sur les processus de séparation et de définir leur point de fonctionnement optimal. L’influence d’une décharge à barrière diélectrique sur la charge triboélectrique et la séparation électrostatique de mélanges plastiques a été étudiée. Les travaux réalisés dans cette thèse ont confirmé la séparabilité électrostatique de mélanges de matériaux granulairesThe experimental approach used in this thesis was aimed at the study of the feasibility of the electrostatic separation of a wide range of granular mixtures from waste electric and electronic equipment (conductive – insulator, conductive – conductive, insulator – insulator). Three physical mechanisms of electrical charging have been employed: electrostatic induction, corona discharge and triboelectric effect. A tribocharging device and two industrial electrostatic separators have been designed and engineered. The rotating cylinder tribocharging device allows the triboelectric charging of plastics. The industrial separator prototype was firstly built for processing conducting – insulator granular mixtures and then adapted for insulator – insulator separation. This prototype, which enables the use of all three electrical charging mechanisms, served as model for the CITF company first industrial electrostatic separator for the recycling of metals and plastics from electric cable wastes. Charge and mass measurement, as well as modelling and visualization of particle trajectories by a high-speed camera facilitated the investigations. Design of experiments method was used to define the influential factors and find the optimum operating conditions of the separation processes. Dielectric barrier discharge exposure of granular plastics may enhance the efficiency of the triboelectric charging of these materials and hence facilitate their electrostatic separation. These researches have confirmed the feasibility of the electrostatic separation of a wide variety of granular mixtures
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Bernaz, Lucien. "Étude du transfert de chaleur à la frontière supérieure d'un bain fluide avec dissipation volumique de puissance." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10021.
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Le travail presente concerne une etude theorique et experimentale du transfert de chaleur a la frontiere superieure d'un bain liquide soumis a dissipation volumique de puissance (dans un regime de turbulence developpee). Le probleme est ramene a celui de la convention turbulente de rayleigh-benard (convection sans source interne de chaleur). Deux modes de transfert de chaleur sont recenses dans la litterature : le regime de turbulence faible et le regime de turbulence forte. L'approche theorique est basee sur une interpretation phenomenologique des ecoulements pariet aux responsables de la majeure partie du transfert de chaleur (turbulence faible). Le modele theorique est valide de maniere satisfaisante par les resultats experimentaux. Ces derniers ont ete obtenus lors d'etudes parametriques dans differents dispositifs : la section d'essai marabec (convection de rayleigh-benard, echelle 1:20 du cas simule) pour la turbulence faible et la section d'essai bali (convection avec source interne de chaleur, echelle 1:1 du cas simule) pour la turbulence forte. Les mesures sont en partie obtenues grace a une technique de visualisation, la fluorescence induite par laser.
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Khelif, Djamal. "Contribution a l'etude de la couche de melange plane : conditions de formation et evolution de la structure tourbillonnaire." Poitiers, 1987. http://www.theses.fr/1987POIT2256.
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Etude experimentale de la structure tourbillonnaire dans une zone de melange confinee formee par la rencontre de deux ecoulements plans paralleles debouchant a vitesses differentes dans un canal rectangulaire. Visualisation des deux ecoulements incidents permettant de determiner l'influence de ces derniers sur les grosses structures coherentes. Traitement numerique de sequences d'images
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Beudon, Didier. "Etude par microscopie electronique a balayage de la structure en domaines ferroelectriques des cristaux de batio : :(3) tires." Nantes, 1987. http://www.theses.fr/1987NANT2053.
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Etude des domaines ferroelectriques par observation optique, puis attaque chimique. Les cristaux n'ayant subis aucune preparation destructrice, sont observes par microscopie electronique a balayage. L'evolution de la structure en domaines ferroelectriques en fonction de la temperature est suivie en temps reel. La visualisation des domaines ferroelectriques est confirmee par decoration avec agcl
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STRZELECKI, ALAIN. "Etude du detachement tourbillonnaire en ecoulement perturbe : application a la debimetrie-vortex." Toulouse 3, 1989. http://www.theses.fr/1989TOU30040.
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Croquette, Vincent. "Etude des structures convectives de Rayleigh-Bénard en géométrie étendue." Paris 6, 1986. http://www.theses.fr/1986PA066050.
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Analyse de la transition spatio-temporelle vers le chaos dans les écoulements de type Rayleigh-Bénard. On mesure l'équivalent des constantes élastiques d'une structure de rouleaux. On détermine la sélection du nombre d'onde réalisée par les dislocations, les joints de grains et les ombilics. On propose une méthode de visualisation des structures convectives dans les gaz.
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Mansur, Sergio Said. "Amélioration des échangeurs thermiques tubulaires par l'utilisation d'inserts hélicoïdaux à l'extérieur des tubes." Grenoble 1, 1993. http://www.theses.fr/1993GRE10192.
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Ce travail propose une etude numerique et experimentale du comportement thermohydraulique des echangeurs multitubulaires munis de bandes vrillees a l'exterieur des tubes. Des lois de frottement et d'echange thermique au sein de cette geometrie ont ete determinees experimentalement et programmees dans le logiciel trio developpe au commissariat a l'energie atomique, cea , avec une modelisation du type milieu poreux. Des mesures de pression et de vitesse, ainsi que des visualisations de l'ecoulement ont ete realisees sur un echangeur construit en plexiglas transparent. Les resultats obtenus dans cette etape ont permis d'evaluer la distribution du debit a l'interieur de l'appareil et de degager les elements necessaires a la validation des calculs. L'adequation du modele pour une description macroscopique de l'ecoulement a ete confirmee par des nombreuses comparaisons entre donnees numeriques et experimentales. Une analyse comparative entre differents types d'echangeurs, realisee a l'aide de la simulation, a mis en evidence la performance thermohydraulique satisfaisante de ce nouveau type d'echangeur. Enfin, l'aspect de la diffusion turbulente a l'interieur du faisceau tubulaire a ete aborde par une experience simple de visualisation. D'un point de vue qualitatif, ces essais ont clairement montre que la presence des inserts favorise le melange et la dispersion des proprietes transferables au sein du fluide, qualifiant ainsi les bandes helicoidales en tant de promoteurs de turbulence
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Zara, Henri. "Système d'acquisition vidéo rapide : application à la mécanique des fluides." Saint-Etienne, 1997. http://www.theses.fr/1997STET4012.
Full textAbstract:
Les systèmes de vision sont aujourd'hui largement employés pour les études expérimentales en mécanique des fluides. Les techniques d'acquisition d'images se heurtent cependant à une limitation technologique concernant la cadence et la résolution des images. De nouveaux capteurs d'images électroniques rapides, mais également certaines méthodes d'exposition permettent d'apporter des solutions à ce problème. Nous présentons dans ce mémoire un système d'acquisition vidéo rapide élaboré autour d'une plate-forme expérimentale de mécanique des fluides. Ce système est constitué en particulier : d'une camera CCD numérique (8bits) de résolution 512x512 pixels avec une cadence de 100 i/s ; d'un système de synchronisation qui assure les différents modes d'exposition des images ainsi que la synchronisation des éléments de la plate-forme. L'ensemble est commandé par un ordinateur PC, pour la configuration des paramètres ainsi que pour le stockage des images. La technique d'éclairage mise en oeuvre est la tomographie laser. Un choix technologique original nous a conduit au couplage de la camera à un intensificateur de lumière. Ce choix permet l'utilisation de sources laser continues de faible puissance. Il offre également de larges possibilités d'exposition des images par la commande de la porte optique de l'intensificateur. Dans une première partie nous présentons une étude détaillée des capteurs d'images à semi-conducteur, ainsi que des intensificateurs d'images. Les descriptions techniques concernant la réalisation de la caméra et du système de synchronisation sont ensuite exposées. L'ensemble d'acquisition vidéo final met en oeuvre deux cameras synchronisées permettant l'enregistrement d'une séquence de paires d'images d'occurrence très proche (50 ns). Quelques exemples expérimentaux permettent de confirmer les possibilités de notre système
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Cortazar, Miguel Angel. "Le Cavermod, modèle physique de l'érosion de cavitation : qualification expérimentale et numérique." Université Joseph Fourier (Grenoble ; 1971-2015), 1994. http://www.theses.fr/1994GRE10089.
Full textAbstract:
Le cavermod est un dispositif entièrement original destiné à simuler les tourbillons cavitants dont l'efficacité agressive dans les machines hydrauliques a été remarquée depuis plusieurs années. Ce dispositif permet de fixer la valeur des trois paramètres qui caractérisent le tourbillon cavitant: son taux de rotation, sa taille et sa vitesse d'implosion. L'étude expérimentale porte à la fois sur la réalisation du dispositif, sur l'équipement de mesure nécessaire à l'observation de l'écoulement crée (durée de vie: quelques millisecondes, vitesse d'implosion comprise entre 70 et 700 m/s), sur l'histoire de cet écoulement et sur les corrélations que l'on peut établir entre l'écoulement et les marques d'érosion formées sur des éprouvettes métalliques. Un modèle numérique permettant le suivi de l'interface liquide-vapeur donne une valeur de la distribution de la pression qui est en accord avec les valeurs expérimentales. L'étude a permis d'une part de cerner l'instant ou les évènements critiques d'érosion ont lieu et d'autre part de déterminer les bases d'une optimisation du dispositif
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Desrayaud, Gilles. "Analyse de stabilite lineaire dans un milieu semitransparent : determination experimentale des limites de stabilite dans un milieu transparent." Paris 6, 1987. http://www.theses.fr/1987PA066089.
Full textAbstract:
Etude de la stabilite des regimes d'ecoulement de convection naturelle dans un fluide semi-transparent confine entre deux parois verticales chauffees differentiellement. Resolution des equations de l'ecoulement et du probleme aux valeurs propres par une methode spectrale tau utilisant les polynomes de chebyshev. Etude experimentale des limites de stabilite dans des cavites verticales remplies d'air par interferometrie holographique et injection de fumee
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Peerhossaini, Hassan. "L'instabilite d'une couche limite sur une paroi concave : les tourbillons de gortler." Paris 6, 1987. http://www.theses.fr/1987PA066023.
Full textAbstract:
Etude en canal hydrodynamique de processus de formation des rouleaux de goertler pres du seuil d'instabilite. Visualisation par fluorescence induite par laser et mesure du champ de vitese par anemometrie laser doppler. On identifie trois instabilites secondaires et on propose un modele simple decrivant la premiere
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Rouland, Eric. "Etude et développement de la technique de vélocimétrie par intercorrélation d'images de particules. Application aux écoulements en tunnel hydrodynamique." Rouen, 1994. http://www.theses.fr/1994ROUES078.
Full textAbstract:
La vélocimétrie par intercorrélation d'images de particules (V. I. I. P. ) a fait l'objet d'un développement complet ayant pour but l'étude d'écoulements dans un tunnel hydrodynamique. Elle consiste en une analyse bidimensionnelle par intercorrélation (corrélation-croisée) de deux images prises simultanément par un capteur CCD standard. Ces images sont obtenues en éclairant, par un plan laser, des particules préalablement ensemencées dans l'écoulement. L'algorithme de corrélation-croisée a été comparé au traitement généralement utilisé : l'autocorrélation, et ceci à l'aide d'un programme générateur d'images simulées. Cette comparaison montre que l'intercorrélation d'images séparées résout à la fois le problème du signe et des mesures de vitesse autour de zéro, cela permet de bénéficier d'une dynamique de vitesse maximum dans la fenêtre d'analyse. Elle met aussi en évidence qu'on peut accepter des densités de particules beaucoup plus élevées et du même ordre que la densité utilisée pour la visualisation par tomographie. Enfin, nous abordons l'application de la méthode aux écoulements dans un tunnel hydrodynamique autour de profils immergés (cylindre, hélice). Nous montrons qu'en dépit d'un ensemencement utilisant des microbulles d'air de différents diamètres et en faible concentration, la V. I. I. P. Permet d'étudier les écoulements propres au tunnel. Dans ce contexte, les informations instantanées, obtenues après l'utilisation de critères de validation de vecteurs vitesse et l'application de post-traitements, permettent ainsi l'analyse de phénomènes de fluctuation spatiale qui apparaissent par exemple dans le sillage d'un cylindre.