Έγινε λήψη σήματος μέσω πιεζοκρυστάλλων και έπειτα το σήμα επεξεργάστηκε κατάλληλα μέσω του αναπτυξιακού περιβάλλοντος και έγινε διάγνωση για την κατάσταση λειτουργίας της μηχανής. / We took a signal with piezoelectrics and we processed the signal through a program and we mwde a diagnosis about the functionality of the four cycle machine.

Στην παρούσα διπλωματική εργασία ασχοληθήκαμε με το θέμα της μελέτης και διάγνωσης σφαλμάτων στάτη μιας ασύγχρονης μηχανής. Μοντελοποιήθηκε και αναλύθηκε η λειτουργία ενός ασύγχρονου τριφασικού κινητήρα κλωβού, σε υγιή κατάσταση αλλά και υπό συνθήκες σφάλματος. Πιο συγκεκριμένα, με τη χρήση του προγράμματος πεπερασμένων στοιχείων σε δυο διαστάσεις εξομοιώθηκαν πιθανά σφάλματα στο στάτη της ασύγχρονης μηχανής. Αναλυτικότερα, στο πρώτο κεφάλαιο παρουσιάζονται κάποιες βασικές αρχές λειτουργίας των ασύγχρονων μηχανών, μελετώνται τα κυριότερα σφάλματα που συναντώνται σε αυτές τις μηχανές και παρουσιάζονται οι γνωστότερες διαγνωστικές μέθοδοι σφαλμάτων που υπάρχουν στη βιβλιογραφία. Κυρίως αναλύεται η μέθοδος διάγνωσης σφαλμάτων που χρησιμοποιεί την ανάλυση στο πεδίο της συχνότητας του ρεύματος στάτη (MCSA) η οποία και χρησιμοποιείται τελικά για τη διάγνωση των συγκεκριμένων σφαλμάτων. Ειδικότερα, μελετήθηκαν δυο ειδών σφάλματα στάτη, τα οποία είναι πιθανόν να συμβούν σε αυτήν τη μηχανή, το βραχυκύκλωμα κάποιων σπειρών εντός της ίδιας αυλάκωσης μιας φάσης και το βραχυκύκλωμα σπειρών σε δυο γειτονικές αυλακώσεις της ίδιας πάλι φάσης του στάτη τα οποία και μελετώνται αναλυτικά παρακάτω. Στο επόμενο κεφάλαιο εξομοιώθηκαν τα δύο μοντέλα με σφάλμα, όπως προαναφέρθηκε με χρήση του προγράμματος πεπερασμένων στοιχείων κάνοντας όλες τις απαραίτητες τροποποιήσεις στις παραμέτρους των αρχικών μοντέλων ώστε να απεικονιστούν στα μοντέλα τα σφάλματα που επιθυμούμε. Στο τρίτο κεφάλαιο παρουσιάζονται όλες οι γραφικές παραστάσεις των ηλεκτρομαγνητικών μεγεθών για όλες τις περιπτώσεις όπως αυτές προέκυψαν από την ανάλυση με το πρόγραμμα της Opera -2d. Συγκεκριμένα, τα μοντέλα αναλύθηκαν με έναν επιλυτή που λαμβάνει υπ’ όψιν και την κίνηση του δρομέα (RM solver), όπου ενώ η μηχανή στρέφεται με σταθερό αριθμό στροφών στην ονομαστική κατάσταση βλέπουμε τη συμπεριφορά της με και χωρίς τα σφάλματα. Στο τελευταίο κεφάλαιο χρησιμοποιούνται οι διαγνωστικές μέθοδοι για την ανίχνευση των σφαλμάτων και παρατίθενται τα αποτελέσματά τους. Πιο συγκεκριμένα, αναλύθηκε το φάσμα συχνοτήτων των κυματομορφών του ρεύματος στάτη και της ηλεκτρομαγνητικής ροπής (FFΤ), ώστε να εντοπιστούν οι συχνότητες στις οποίες εισάγονται αρμονικές λόγω του σφάλματος. Επίσης μελετήθηκε η μορφή της χρονικής συνάρτησης του μαγνητικού πεδίου σε ορισμένα χαρακτηριστικά σημεία της μηχανής. Τέλος παρατίθενται τα συμπεράσματα , μαζί με την συνεισφορά της εργασίας καθώς και θέματα για διερεύνηση. / In this paper we dealt with the topic of the study and diagnosis of errors stator asynchronous machine. Modeled and analyzed the function of a three-phase asynchronous motor cage, but in a healthy state and under fault conditions.

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Mechatronics is an exciting research area that stemmed from huge progress in computer technology from the 1970s onwards. In such systems, computer controlled electronic and mechanical devices interact so intimately that it is impossible to tell where the one ends and the other begins. A mechatronic project aimed at automated manufacturing was undertaken by the Department of Industrial Engineering at the University of Stellenbosch as part of their programme in mechatronics. ROYIC was the industrial partner in the joint venture. ROYIC manufactures a front loader that is used on tractors. The front loader fits on a tractor by means of a kit that has to be manufactured specially for each type of tractor. The design of the kit needed many welding joints, which lead to a difficult and expensive manufacturing process. A bending press that was capable of bending pre-cut steel into a predefined shape was identified as a viable solution. The mechanical design for the project was done by ROYIC, while the University was responsible for the electronic control. Bending is carried out by pushing a flat bar over a Y-block into the bending position which can be read from a position encoder. The bending blade then bends the metal until the appropriate angle is reached. It is impossible to predict the resulting angle by means of analytical techniques. This is due to non-linear behaviour caused by spring-back. The position of the bending blade is read with an incremental encoder. An empirical equation is used to convert the distance read by the sensor into the appropriate angle. The parameters are deduced by means of non-linear regression methods. A mean square error of 0.069 was obtained for the equation when operating in the linear area of the plastic region of bending. A software application was written to enable ROYIC to deduce the needed parameters of the equation for all types of steel. Pulse control was used to control the bending blade. The blade moves continuously until a pulse band is reached. The blade is pulsed from there into a dead band. Consequently the accuracy of the machine is determined by the width of the dead band. The control program is capable of executing bend sequence files to enable the operator to perform a sequence of bends on a metal bar. Safety was of great importance in the design. The control system was designed to give priority to safety signals over other control signals. Dangerous situations owing to computer failure are thus prevented. / AFRIKAANSE OPSOMMING: Megatronika is 'n opwindende navorsingsarea wat ontstaan het uit groot vooruitgang in rekenaartegnologie vanaf 1970. In megatroniese sisteme werk rekenaar beheerde elektroniese en meganiese toestelle so nou saam dat dit onmoontlik is om agter te kom waar die een begin en die ander eindig. 'n Megatronika projek gerig op vervaardigings outomatisasie is onlangs onderneem deur die Departement van Bedryfsingenieurswese van die Universiteit van Stellenbosch as deel van hul program in megatronika. ROVle was die industriële vennoot in die projek. ROVle vervaardig implemente vir gebruik op plase. Een van hul produkte is 'n laaigraaf wat met 'n hegstuk op 'n trekker pas. Die hegstuk moet spesifiek vir elke tipe trekker ontwerp word wat gelei het tot 'n ontwerp met baie sweislaste wat 'n tydrowende vervaardigingsproses vereis. 'n Staal buigmasjien wat vooraf gesnyde staal in 'n spesifieke vorm kan buig sou hierdie probleem kon oorbrug. Die meganiese ontwerp vir die masjien is gedoen deur ROVle terwyl die Universiteit verantwoordelik was vir die elektroniese beheer. Staal word gebruik deur 'n staalbalk te skuif oor die buigbed tot in die buigposisie wat afgelees word vanaf' n posisie enkodeerder. Die buiglem buig dan die staal in die benodigde hoek. Geen analitiese metodes bestaan om die buighoek te voorspel nie weens terugspringing. Die posisie van die buiglem word ingelees met behulp van 'n inkrementeie enkodeerder. 'n Empiriese vergelyking word gebruik om die afstand beweeg om te skakel in 'n buighoek. Die verskillende parameters word afgelei deur middel van regressie metodes. Die gemiddelde foute kwadraat was 0.069 wat getoets is vir slegs die lineêre area van die plastiese gebied. 'n Program is geskryf wat ROVle instaat stelom die benodigde parameters self af te lei. Puls beheer is gebruik op die beheer van die buiglem. Die lem beweeg kontinu tot binne die puls band en word daarvandaan gepuls tot by die stopband. Die grootte van die stopband bepaal dus die akkuraatheid van die masjien. Die beheerprogram kan ook buig sekwensie lêers uitvoer wat die operateur instaat stelom 'n reeks van buigings op 'n staal balk uit te voer. Veiligheid het deurgaans 'n belangrike rol gespeel in die ontwerp van die masjien. Die stelsel is ontwerp om prioriteit te gee aan veiligheidseine bo enige ander beheersein. Gevaarlike situasies wat mag ontstaan as die rekenaar sou faal, word dus voorkom.

Thesis (MScEng) -- Stellenbosch University, 2003. / ENGLISH ABSTRACT: High Speed Cutting (HSC), specifically milling is a significant contemporary development in machining. The Die and Mould industry is experiencing a difficult business climate. There is competitive pressure for shorter lead times and lower prices. Companies worldwide, are under financial pressure, to meet the challenges of a globalised business environment. The conventional position of milling and Electric Discharge Machining (EDM / Erosion) is discussed with the proposal to use HSC and EDM as complementary processes. Among new developments the progress in computer infrastructure is prominent. There is also a paradigm shift that should be made from experience based process planning to modern, up to date knowledge based process planning. High Speed Cutting is now a mature process capable of acceptable process security. The examples detailed include crankshaft-forging tooling, injection moulding tooling and powder sintering tooling. A process chain is proposed for the complementary HSC / EDM process with estimated illustrative time saving over the conventional EDM dominated process. HSC will be the first process removing the bulk of the material, finishing as far as possible and with EDM finally machining the features that will be difficult or impossible with HSC. To facilitate the use of the complementary processes a decision model to determine the crossover point between HSC and EDM is proposed. The decision model is firstly presented as a flow diagram to determine whether the task is a candidate for HSC only, EDM only, or the complementary HSC / EDM process. The key parameters e.g tool H d ratio are variables. This is in order that the flow diagram may be adapted to a specific machine tool infrastructure and expertise level in a company. The second part is a HSC machining time estimation model. The time is estimated per segment roughed, semi-finished, or finish machined. The model is in an empirical form with constants that can be adapted to the practices of a specific company. It is intended that the constants also be periodically revised to reflect the development in HSC expertise that will occur during the use HSC in the company. The model is practically evaluated with a case study, including the detail steps, not included in the model. Conceptual guidelines are given for software implementation. It is concluded that HSC and EDM are suitable complementary processes. It is a necessary prerequisite to use pallets to avoid multiple set-ups. Complementary HSC and EDM is especially appropriate for the gradual deployment and skill development for HSC. HSC and complementary HSC / EDM is considered the opportunity for companies to make a major breakthrough in lead time and operating expense if the necessary pallet/fixturing equipment, CAx infrastructure and human capability is available. / AFRIKAANSE OPSOMMING: Hoe Spoed Masjinering (HSC), spesifiek frees is ‘n betekenisvolle ontwikkeling in masjinering. Die Gereedskap en Gietvorm bedryf ervaar ‘n moelike besigheidsklimaat. Daar is kompeterende druk vir korter lewertye en laer pryse. Maatskappye wereldwyd is onder finansiele druk om in die geglobaliseerde besigheidsmilieu te presteer. Die posisie van frees en Elektriese Ontladingsmasjinering (EDM / Vonkerosie) word bespreek met die voorstel om HSC en EDM as komplementere prosesse te gebruik. Onder die nuwe ontwikkelings is daar prominente vooruitgang in rekenaarinfrastruktuur. Daar is ook ‘n paradigmaverskuiwing nodig van ondervinding gebaseerde na op datum kennis gebaseerde proses beplanning. HSC is nou ‘n ontwikkelde proses met voldoende prosessekerheid. Die voorbeelde sluit krukas smee gereedskap, inspuitgiet gereedskap, en poeier-sinter persgereedskap in. ‘n Prosesketting word voorgestel vir die komplementere HSC / EDM proses met ‘n beraamde illustratiewe tydbesparing oor die konvensionele EDM gedomineerde proses. HSC sal die eerste proses wees wat die meerderheid van die materiaal verwyder en oppervlaktes so ver as moontlik afwerk, met EDM wat die finale afwerking doen en ook die masjinering wat vir moeilik haalbaar of onmoontlik is vir HSC. Om die gebruik van die komplementere prosesse te fasiliteer, word ‘n beluitnemingsmodel vir die oorgangspunt tussen HSC en EDM voorgestel. Dit word eerstens as vloeidiagram gebruik om die taak te klassifiseer vir HSC alleen, EDM alleen of vir komplementere HSC en EDM. Die sleutelparameters, bv die beitel 116 verhouding, is veranderlikes. Dit is sodat die vloeidiagram aangepas kan word by ‘n spesifieke masjienvermoe en ‘n kundigheidsvlak in ‘n maatskappy. Die tweede deel is ‘n HSC masjineringstyd model. Die tyd word beraam per segment uitgerof, afgewerk, of finaal afgewerk. Die model is in empiriese vorm met konstantes wat kan aangepas word by die praktyke van ‘n firma. Dit is die bedoeling dat die konstantes periodiek aangepas word om die ontwikkeling te weerspieel wat in die maatskappy plaasvind. Die model word prakties evalueer met ‘n gevallestudie, insluitend die detailstappe, wat nie in die modelformulering ingesluit is nie. Konseptuele riglyne word gegee vir programmatuur implementering. Die gevolgtrekking word gemaak dat HSC en EDM geskikte komplementere prosesse is. Dit is ‘n voorvereiste om pallette te gebruik om veelvuldige opstellings te vermy. Komplementere HSC / EDM is veral toepaslik om HSC geleidelik in ‘n firma te ontplooi en kundigheid te bou. Die HSC / EDM kombinasie word ook die geleentheid geag vir firmas om ‘n deurbraak te maak in lewertyd en bedryfsuitgawes as die nodige pallettoerusting, CAx infrastruktuur en menslike vermoe beskikbaar is.

Doctorat en philosophie et lettres / info:eu-repo/semantics/nonPublished

Self presentation is evolving; with digital technologies, with the Web and personal publishing, and then with mainstream adoption of online social media. Where are we going next? One possibility is towards a world where we log and own vast amounts of data about ourselves. We choose to share - or not - the data as part of our identity, and in interactions with others; it contributes to our day-to-day personhood or sense of self. I imagine a world where the individual is empowered by their digital traces (not imprisoned), but this is a complex world. This thesis examines the many factors at play when we present ourselves through Web technologies. I optimistically look to a future where control over our digital identities are not in the hands of centralised actors, but our own, and both survey and contribute to the ongoing technical work which strives to make this a reality. Decentralisation changes things in unexpected ways. In the context of the bigger picture of our online selves, building on what we already know about self-presentation from decades of Social Science research, I examine what might change as we move towards decentralisation; how people could be affected, and what the possibilities are for a positive change. Finally I explore one possible way of self-presentation on a decentralised social Web through lightweight controls which allow an audience to set their expectations in order for the subject to meet them appropriately. I seek to acknowledge the multifaceted, complicated, messy, socially-shaped nature of the self in a way that makes sense to software developers. Technology may always fall short when dealing with humanness, but the framework outlined in this thesis can provide a foundation for more easily considering all of the factors surrounding individual self-presentation in order to build future systems which empower participants.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2015. / Submitted by Guimaraes Jacqueline (jacqueline.guimaraes@bce.unb.br) on 2015-11-13T13:21:13Z No. of bitstreams: 1 2015_EduardoFerreiraDosSantos.pdf: 5080466 bytes, checksum: 765cdde2da22f26b7b3f4a30f68a0074 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2015-11-25T17:53:13Z (GMT) No. of bitstreams: 1 2015_EduardoFerreiraDosSantos.pdf: 5080466 bytes, checksum: 765cdde2da22f26b7b3f4a30f68a0074 (MD5) / Made available in DSpace on 2015-11-25T17:53:13Z (GMT). No. of bitstreams: 1 2015_EduardoFerreiraDosSantos.pdf: 5080466 bytes, checksum: 765cdde2da22f26b7b3f4a30f68a0074 (MD5) / Social machine é uma abordagem relativamente nova para tratar problemas relevantes à sociedade, integrando em um software elementos computacionais e sociais. Pode ser considerada uma extensão da Web Semântica, criando o processo por meio do qual as pessoas executam as tarefas criativas e as máquinas realizam a administração dos dados. Essa Dissertação de Mestrado apresenta uma proposta de aplicação do conceito ao tema violência e criminalidade, assunto bastante relevante nos países da América Latina e Caribe – LAC. Trata-se de uma extensão do conceito de Social Machines que aplica duas estratégias publicadas recentemente para obter informações semânticas de dados oriundos de redes sociais, além de publicar o resultado como um serviço de Dados Abertos. O processo de desenvolvimento foi documentado para fornecer um procedimento sistemático, e uma aplicação exemplo foi construída para identificar eventos relacionados a violência e criminalidade. O procedimento proposto foi validado e testado em modelos formais recentemente desenvolvidos para o tema. Os resultados da extração de dados são também comparados aos dados oficiais, de forma a identificar similaridades. / Social machine is a rather new approach to deal with relevant problems in society, blending computational and social elements into software. It can be an extension of the Semantic Web, creating processes in which people do the creative work and the machine does the data administration. This professional masters dissertation presents a proposal to apply this approach in violence and criminality domain, a relevant matter to Latin America and Caribbean – LAC – countries. It extends Social Machines by applying two recently published strategies to obtain semantics over social networks data and publishing it as a Linked Open Data service. The development procedure was documented to provide a systematic procedure and an example application is presented to identify violence and criminality events. The resulting procedure validation was be done by testing against recently developed formal models in the research area. Criminal activity data extraction results were also compared to official data, in order to identify similarities.

Between 1% and 1.4% of people who engage in gambling behaviors lead to disordered or pathological gambling (Whiting & Dixon, 2015), while 44% of all money spent on legal gambling is done so with slot machines (Choliz, 2010). Various behavioral concepts have been theorized as a possible source of gambling addition; losses disguised as wins (LDWs), near-miss, gamblers’ fallacy, illusions of control, and verbally constructed self-rules related to these topics. The current study sought to extend the previous research on condition discrimination in altering slot machine preference while also analyzing the effects of vocalized self-rules during slot machine selection. Conclusions are drawn regarding results comparing cumulative selection to various vocal statement categories. Limitations are expressed and future research is suggested.

Early and accurate prediction of the compressive strength of concrete is important in the construction industry. Modeling the compressive strength of concrete to obtain a balance and equality between prediction accuracy, time and uncertainty of the prediction is a very difficult task due to the highly nonlinear nature of concrete. For structural engineering purposes, the 28- day compressive strength is the most relevant parameter. In this study, an attempt has been made to predict the 28-day compressive strength of concrete using Relevance Vector Machine (RVM). An RVM belongs to the class of sparse kernel classifiers, which are powerful tools in classification and regression. It has a model of identical functional form to the popular and state-of-the-art `Support Vector Machine (SVM)'. The benefits of using RVM include automatic estimation of nuisance parameters, probabilistic prediction and the ability to model complex data with little information. A total of 425 different data of high performance mix designs were collected from the University of California, Irvine repository. The data used to predict the compressive strength consisted of nine components. The RVM model was trained and tested using 395 and 30 data sets respectively. The model's performance was assessed at the end of the training and testing period using four performance measures; coefficient of determination, root-mean-square error, percentage of relevance vectors and residual plots. All the performance measures confirmed the accuracy of the model. The results of the study suggested that RVM is an effective tool for predicting the 28- day compressive strength of concrete from its mix ingredients.

El presente trabajo de tesis propone una metodología para la construcción de un modelo predictivo de fugas voluntarias, el cual tiene como objetivo la identificación temprana de los clientes que presentan mayores tendencias a la fuga.