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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Visual Data Mining : An Approach to Hybrid 3D Visualization

Zall, Davood January 2012 (has links)
By increasing the volume and complexity of datasets, Visual Data Mining (VDM), new visualization techniques evolved and new techniques released. However, some of these techniques performing well and cover all expectations; the others failed to save their positions. The main issue of such techniques is problem dependency.In this study, after a short description about necessity of Visual Data Mining techniques, I will provide a classified review of previous researches. This will result in a deep understanding as well as simple accessibility to previous researches, in a concise manner. This will facilitate the extraction of the specifications of 3D visualization technique and will provide a comprehensive knowledge of this technique in a classified manner. After that, all possible combination of 3D visualization technique will review.3D Visualization technique as a popular technique is a concrete foundation for visualization of multi-dimensional datasets, but it has some limitations. To overcome these limitations, previous studies in literature as well as the experiences of professionals will gather. The results will prove the theoretical findings as well as offering new hybrid techniques (combination with 3D visualization and other visual data mining techniques).The contribution of professionals will empower and complement the results of this study, as they can address solutions for the weaknesses of 3D Visualization technique in their business which is new combination of techniques. These combinations of techniques will create the basis for future researches in order to discover new limitations and provide solutions to overcome by use of hybrid techniques. / Program: Magisterutbildning i informatik
2

Uma abordagem de visualização híbrida para apoiar a exploração de conjuntos de dados / A hybrid visualization approach to support the exploration of data sets

Silva, Lenon Fachiano 22 January 2018 (has links)
Submitted by Lenon Fachiano (lenon_fachiano@hotmail.com) on 2018-05-09T17:37:15Z No. of bitstreams: 1 abntex2-LenonFachiano.pdf: 5626662 bytes, checksum: e8f64d248c338cf11e9e65b08961374f (MD5) / Approved for entry into archive by Elza Mitiko Sato null (elzasato@ibilce.unesp.br) on 2018-05-09T17:50:40Z (GMT) No. of bitstreams: 1 silva_lf_me_sjrp_int.pdf: 5626662 bytes, checksum: e8f64d248c338cf11e9e65b08961374f (MD5) / Made available in DSpace on 2018-05-09T17:50:40Z (GMT). No. of bitstreams: 1 silva_lf_me_sjrp_int.pdf: 5626662 bytes, checksum: e8f64d248c338cf11e9e65b08961374f (MD5) Previous issue date: 2018-01-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Técnicas de visualização têm sido largamente utilizadas na exploração de conjuntos de dados. Uma estratégia comum é empregar diferentes técnicas para facilitar a investigação, permitindo que o usuário tenha diferentes perspectivas de um mesmo conjunto de dados. Nessas situações, um mecanismo de coordenação auxilia o usuário na troca de contexto entre diferentes visões. Adicionalmente, uma estratégia adotada por algumas abordagens é a de combinar diferentes técnicas de visualização em uma única visão, criando uma visualização híbrida. Este trabalho apresenta o desenvolvimento de uma abordagem de visualização híbrida que utiliza uma técnica de visualização para destacar o relacionamento entre instâncias com outra técnica de visualização para destacar o relacionamento entre atributos. Como resultado, foi obtida uma metodologia de combinação de técnicas que apoia o processo de exploração de conjuntos de dados multidimensionais e auxilia no entendimento do espaço de característica, permitindo a detecção de fronteiras compartilhadas entre agrupamentos e a resolução de problemas de rotulação. / Visualization Techniques have been widely used in the exploration of datasets. A common strategy is to employ different techniques to facilitate research, allowing the user to have different perspectives from the same dataset. In these situations, a coordination mechanism helps the user in the exchange of context between different visions. In addition, a strategy adopted by some approaches is to combine different visualizations into a single view, creating a hybrid visualization. This paper shows the development of a hybrid visualization approach that uses a visualization technique to highlight the relationship between instances with another to highlight the relationship between attributes. This approach supports the process of exploring multidimensional datasets and assists in understanding the featuring space, allowing the detection of shared boundaries between groupings and the resolution of labeling problems. As a result, a methodology combining techniques was developed that supports the process of exploring multidimensional data sets and helps in understanding the characteristic space, allowing the detection of shared boundaries between groupings and the resolution of labeling problems.
3

Investigation of the ESX-4 secretion system interactome of Mycobacterium tuberculosis

Smit, Michelle 12 1900 (has links)
Thesis (MScMedSc (Biomedical Sciences. Medical Biochemistry))--University of Stellenbosch, 2010. / Bibliography / ENGLISH ABSTRACT: The genome of the pathogen Mycobacterium tuberculosis contains five copies of the ESAT-6 (ESX) gene cluster region, which encodes for a novel type VII secretion system. These gene cluster regions, which are directly involved in pathogenicity and phagosomal escape, contain genes encoding exported T-cell antigens ESAT-6 and CFP-10. The mechanism of action of the ESX secretion system however, remains largely unknown. This study focused on ESX gene cluster region 4 (ESX-4), which has been shown to be the most ancestral region and is also present in other species of Mycobacteria and even in other high G+C Gram-positive bacteria, such as Corynebacterium diptheriae and Streptomyces coelicolor. This project aimed to investigate the protein-protein interactions of ESX-4 of M. tuberculosis in the model organism Mycobacterium smegmatis by means of Mycobacterial Protein Fragment Complementation (M-PFC). M-PFC is a two-hybrid technique which employs two cloning vectors, pUAB300 (conferring resistance to hygromycin B) and pUAB400 (conferring resistance to kanamycin). Genes of interest are cloned into these vectors and co-transformed into the model organism M. smegmatis after which it is expressed as fusion proteins. Interaction of the proteins allows selective growth on a medium containing the antibiotic trimethoprim. Various interactions were identified throughout this region, including selfinteractions as well as the expected interaction between the ESAT-6 and CFP-10 protein family members esxT and esxU. Since this region is ancestral, ESX-4 provides the basic model of the mechanism of secretion of the type VII secretion system. Many similarities were apparent when the interactions identified for ESX-4 were compared to the interactions previously identified in ESX-3. Interactions identified by means of M-PFC provide a basis for the further study of the structure of this secretion system, and should be confirmed by means of other techniques, such as co-immunoprecipitation. Despite the ability of M-PFC to identify protein-protein interactions in a mycobacterial system, and thus overcoming some of the limitations of the classical yeast two-hybrid model, it must still be regarded as a fishing experiment for potential interactions. A further aim of the project was to construct a knock-out of ESX-4 in the model organism M. smegmatis, which contains three ESX regions, namely ESX-1, -3 and -4. Homologous recombination proved to be an effective technique for the construction of the knock-out, also indicating that ESX-4 is not essential for in vitro growth of M. smegmatis. The knock-out strain showed no morphological differences to the wild type strain of M. smegmatis. The knock-out strain will in future be compared to the wild type strain in various functional studies in order to determine the function of the ancestral ESX region. / AFRIKAANSE OPSOMMING: Die genoom van die patogeen Mycobacterium tuberculosis bavat vyf kopieë van die ESAT-6 geen groep gebiede wat kodeer vir ‘n unieke tipe VII sekresie sisteem. Die geen groep gebiede, wat direk betrokke is by patogenisiteit en fagosomale ontsnapping, bevat gene wat kodeer vir die gesekreteerde T-sel antigene ESAT-6 en CFP-10. Die meganisme van die ESX sekresie sisteem is egter steeds tot ‘n groot mate onbekend. Hierdie studie het gefokus op die ESX geen groep gebied 4 (ESX-4), wat voorheen bepaal is om die vroegste kopie van die gebied te wees en wat ook in ander species van Mikobakterieë en hoë G+C Gram-positiewe bakterieë, soos Corynebacterium diptheriae en Streptomyces coelicolor, voorkom. Hierdie projek was daarop gemik om die proteïen-proteïen interaksies van ESX-4 van M. tuberculosis in die model organisme Mycobacterium smegmatis te ondersoek deur middel van Mikobakteriële Proteïen Fragment Komplementasie (M-PFK). M-PFK is ‘n twee-hibried tegniek wat van twee kloningsvektore, naamlik pUAB300 (wat weerstand teen hygromycin B bied) en pUAB400 (wat weerstand teen kanamycin bied) gebruik maak. Gene van belang word in die vektore ingekloneer en in die model organisme, M. smegmatis geko-transformeer, waarna dit as fusieproteïene uitgedruk word. Indien ‘n interaksie tussen die proteïene plaasvind, sal selektiewe groei op ‘n medium wat die antibiotikum trimethoprim bevat, waargeneem word. Verskeie interaksies is in hierdie gebied geïdentifiseer, insluitende self-interaksies, sowel as die verwagte interaksie tussen die ESAT-6 en CFP-10 proteïen familielede esxT en esxU. Aangesien hierdie gebied die vroegste kopie is, bied ESX-4 die basiese model vir die meganisme van sekresie van die tipe VII sekresie sisteem. Wanneer interaksies wat vir ESX-4 geïdentifiseer is met die wat voorheen vir ESX-3 geïdentifiseer is vergelyk word is daar heelwat ooreenkomste. Interaksies wat deur middel van M-PFK geïdentifiseer is, verskaf ‘n basis vir die vêrdere studie van interaksies van hierdie gebied, en sal bevestig moet word deur gebruik te maak van aanvullende tegnieke, soos ko-immunopresipitasie. Ten spyte van die vermoë van M-PFK om proteïen-proteïen interaksies in ‘n mikobakteriële sisteem, wat dus sommige van die beperkings van die klassieke gis twee-hibriedmodel oorkom, te bestudeer, behoort dit steeds as ‘n voorlopige metode van identifikasie beskou te word. ‘n Vêrdere doel van die projek was om ‘n uitslaanmutant van ESX-4 in die model organisme M. smegmatis, wat drie van die ESX gebiede, naamlik ESX-1, -3 en -4 bevat, te skep. Homoloë rekombinasie is bewys om ‘n effektiewe tegniek te wees vir die skep van ‘n uitslaanmuntant en het daarop gedui dat ESX-4 nie essensieel is vir die in vitro groei van M. smegmatis nie. Die uitslaanstam het ook geen morfologiese verskille getoon teenoor die oorspronklike stam nie. Die uitslaanmutant sal in die toekoms gebruik word in ‘n verskeidenheid funksionele studies waar dit vergelyk sal word met die oorspronklike stam, ten einde die funksie van die vroegste ESX-gebied te bepaal. / Medical Research Council of South Africa / National Research Foundation of South Africa / Ernst and Ethel Eriksen Trust
4

Τεχνικές εντοπισμού θέσης κινητού σταθμού κάτω από non line of sight συνθήκες / Mobile location estimation techniques under non light of sight conditions

Καλύβας, Ιωάννης 22 September 2009 (has links)
To θέμα του εντοπισμού των κινητών τηλεφώνων έχει τραβήξει την προσοχή τα τελευταία χρόνια εξαιτίας των απαιτήσεων της Ομοσπονδιακής Επιτροπής Επικοινωνιών για το Enhanced 911 η οποία είναι μια υπηρεσία συναγερμού. Τα ασύρματα συστήματα επικοινωνίας 3ης γενιάς ηταν τα πρώτα που υιοθέτησαν στρατηγικές εύρεσης θέσης στα στάνταρντ τους. Στην διαδικασία της εύρεσης της θέσης υπάρχουν 3 βασικές κατηγορίες μετρήσεων που μπορούμε να χρησιμοποιήσουμε. Η πρώτη εκτιμά το κινητό βασίζοντας τις μετρήσεις στην λαμβανόμενη ισχύ σήματος. Η δεύτερη κάνει χρήση των χρόνων άφιξης ή της διαφοράς των χρόνων άφιξης στους σταθμούς βάσης. Η τρίτη κατηγορία έχει να κάνει με τις γωνίες άφιξης στους σταθμούς βάσης. Όλες οι παραπάνω κατηγορίες μετρήσεων υποβαθμίζονται έντονα από την NLOS διάδοση. Η απουσία ενός LOS μονοπατιού μπορεί να βλάψει σημαντικά την εκτίμηση της πραγματικής θέσης του κινητού. Αντικείμενο της παρούσας διπλωματικής είναι η συγκριτική αξιολόγηση και μελέτη κάποιων δημοφιλών τεχνικών εντοπισμού θέσης απλών και υβριδικών κάτω από διαφορετικά ΝLOS περιβάλλοντα και σε συνδυασμό με άλλες εξίσου σημαντικές παραμετρους όπως ειναι το διαθέσιμο πλήθος σταθμών βάσης σε μια περιοχή, η γεωμετρία ή με άλλα λόγια η θέση του κινητού σε σχέση με τους σταθμους βάσης. Προτείνεται επίσης και μια υβριδική τεχνική για την αντιμετώπιση των παραπάνω καταστρεπτικών επιπτώσεων του NLOS φαινομένου. / The problem of mobile location estimation has recently drawn attention due to Federal Communications Commission (FCC) demands of Enhanced-911 (E911) emergency service. Third Generation (3G) wireless systems were the first to adopt location estimation techniques into their standards. There are three basic types of measurements that can be used for location estimation. The first type includes Received Signal Strength measurements. The second type uses Time of Arrival or Time Difference of Arrival measurements of the signal to the base stations. The third type deals with Angle of Arrival measurements of the received signal. The subject of this work is the comparative evaluation and study of certain popular, simple and hybrid location estimation techniques, under different NLOS environments and in conjunction with other equally important parameters such as the number of available base stations, the geometry of the problem and the position of the mobile relative to the base stations. A hybrid method is also suggested for mitigating the destructive consequences of the NLOS effect.
5

Proactive university library book recommender system

Mekonnen, Tadesse Zewdu January 2021 (has links)
M. Tech. (Department of Information Communication Technology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Too many options on the internet are the reason for the information overload problem to obtain relevant information. A recommender system is a technique that filters information from large sets of data and recommends the most relevant ones based on people‟s preferences. Collaborative and content-based techniques are the core techniques used to implement a recommender system. A combined use of both collaborative and content-based techniques called hybrid techniques provide relatively good recommendations by avoiding common problems arising from each technique. In this research, a proactive University Library Book Recommender System has been proposed in which hybrid filtering is used for enhanced and more accurate recommendations. The prototype designed was able to recommend the highest ten books for each user. We evaluated the accuracy of the results using Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE). A measure value of 0.84904 MAE and 0.9579 RMSE found by our system shows that the combined use of both techniques gives an improved prediction accuracy for the University Library Book Recommender System.

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