• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 502
  • 202
  • 111
  • 59
  • 55
  • 39
  • 38
  • 31
  • 19
  • 17
  • 14
  • 13
  • 8
  • 6
  • 6
  • Tagged with
  • 1296
  • 143
  • 123
  • 121
  • 117
  • 112
  • 108
  • 106
  • 93
  • 88
  • 81
  • 80
  • 73
  • 70
  • 70
  • 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.
861

Contributions to the 3D city modeling : 3D polyhedral building model reconstruction from aerial images and 3D facade modeling from terrestrial 3D point cloud and images

Hammoudi, Karim 15 December 2011 (has links) (PDF)
The aim of this work is to develop research on 3D building modeling. In particular, the research in aerial-based 3D building reconstruction is a topic very developed since 1990. However, it is necessary to pursue the research since the actual approaches for 3D massive building reconstruction (although efficient) still encounter problems in generalization, coherency, accuracy. Besides, the recent developments of street acquisition systems such as Mobile Mapping Systems open new perspectives for improvements in building modeling in the sense that the terrestrial data (very dense and accurate) can be exploited with more performance (in comparison to the aerial investigation) to enrich the building models at facade level (e.g., geometry, texturing).Hence, aerial and terrestrial based building modeling approaches are individually proposed. At aerial level, we describe a direct and featureless approach for simple polyhedral building reconstruction from a set of calibrated aerial images. At terrestrial level, several approaches that essentially describe a 3D urban facade modeling pipeline are proposed, namely, the street point cloud segmentation and classification, the geometric modeling of urban facade and the occlusion-free facade texturing
862

Vyresnio amžiaus žmonių asmenybės savybių ypatumai / Personality features of senior people

Bernotaitė, Dalia 26 June 2014 (has links)
Visame pasaulyje visuomenė sensta, todėl labai svarbu yra pažinti vyresnio amžiaus žmones. Kad senstant keičiasi fizinis pajėgumas, visi žinome, tačiau nuomonių apie tai, kas vyksta su žmogaus asmenybe, yra įvairių. Mano tyrimo tikslas buvo tirti ir palyginti vyresnio amžiaus žmonių asmenybės savybių ypatumus, priklausomai nuo jų gyvenamosios aplinkos, amžiaus ir lyties. Tyrime buvo naudotas NEO-PI-R klausimynas, sukurtas Costa ir McCrae (1992), kurį sudaro 240 teiginių. Tyrime dalyvavo 132 asmenys: 101 tiriamasis – vyresnio amžiaus žmonės, gyvenantys pensionate, likę 31 tiriamasis – jaunesnio amžiaus žmonės. Dar viena imtis palyginimui buvo paimta iš Vilniaus universiteto Filosofijos fakulteto laboratorijos duomenų bazės – tai 67 vyresnio amžiaus žmonės, gyvenantys namie. Rezultatai parodė, jog gyvenamoji aplinka turi įtakos tam tikriems vyresnio amžiaus žmonių asmenybės bruožams, pavyzdžiui, namie gyvenantys vyresnio amžiaus žmonės yra atviresni patyrimui, o pensionato gyventojai – pažeidžiamesni. Tačiau bruožų, kuriais abi imtys yra panašios, vis dėlto yra daugiau. Taip pat nustatyta, jog nepriklausomai nuo gyvenamosios aplinkos, su amžiumi mažėja priešiškumas ir veikla, o didėja – tiesumo išreikštumas. Tyrimas parodė, jog vyresnio ir jaunesnio amžiaus žmonės skiriais tam tikrai asmenybės bruožais: vyresniems labiau būdingas sutariamumas, depresija, šiluma, pasitikėjimas, tiesumas, nuolaidumas ir kuklumas; jaunesniems labiau būdingas priešiškumas, impulsyvumas ir jausmai... [toliau žr. visą tekstą] / In all of the world society is getting older, for that reason it is very important to know seniors better. Everybody knows that people are loosing their physical strength as they get older, but there are many disagreements about what happens with their personalities. The object of the current study was to examine and compare personality features of senior people, depending on their living environment, age and sex. NEO-PI-R questionnaire created by Costa and McCrae (1992) was used in this study, it contains 240 statements. 132 people participated in this study: 101 – nursing home residents, 31 – younger people. More data was taken from Vilnius University Phylosophy faculty laboratory database – it was data about 67 seniors, living at home. The results showed that living environment has influence on some of the seniors’ personality features, for example, seniors who live at home are more open to experience, and nursing home residents are more vulnerable. However personalities of these two groups have more similar traits. The study showed that despite living environment angry hostility and actions decreases with age and straightforwardness increases. Younger and older people differ in these personality traits: for the seniors’ agreeableness, depression, warmth, trust, straightforwardness and modesty are more expressed; for younger people hostility, impulsiveness and feelings are more expressed. Yet conscientiuousness, for example, and all its facets do not depend on age. This... [to full text]
863

Distributed high-dimensional similarity search with music information retrieval applications

Faghfouri, Aidin 29 August 2011 (has links)
Today, the advent of networking technologies and computer hardware have enabled more and more inexpensive PCs, various mobile devices, smart phones, PDAs, sensors and cameras to be linked to the Internet with better connectivity. In recent years, we have witnessed the emergence of several instances of distributed applications, providing infrastructures for social interactions over large-scale wide-area networks and facilitating the ways users share and publish data. User generated data today range from simple text files to (semi-) structured documents and multimedia content. With the emergence of Semantic Web, the number of features (associated with a content) that are used in order to index those large amounts of heterogenous pieces of data is growing dramatically. The feature sets associated with each content type can grow continuously as we discover new ways of describing a content in formulated terms. As the number of dimensions in the feature data grow (as high as 100 to 1000), it becomes harder and harder to search for information in a dataset due to the curse of dimensionality and it is not appropriate to use naive search methods, as their performance degrade to linear search. As an alternative, we can distribute the content and the query processing load to a set of peers in a distributed Peer-to-Peer (P2P) network and incorporate high-dimensional distributed search techniques to attack the problem. Currently, a large percentage of Internet traffic consists of video and music files shared and exchanged over P2P networks. In most present services, searching for music is performed through keyword search and naive string-matching algorithms using collaborative filtering techniques which mostly use tag based approaches. In music information retrieval (MIR) systems, the main goal is to make recommendations similar to the music that the user listens to. In these systems, techniques based on acoustic feature extraction can be employed to achieve content-based music similarity search (i.e., searching through music based on what can be heard from the music track). Using these techniques we can devise an automated measure of similarity that can replace the need for human experts (or users) who assign descriptive genre tags and meta-data to each recording and solve the famous cold-start problem associated with the collaborative filtering techniques. In this work we explore the advantages of distributed structures by efficiently distributing the content features and query processing load on the peers in a P2P network. Using a family of Locality Sensitive Hash (LSH) functions based on p-stable distributions we propose an efficient, scalable and load-balanced system, capable of performing K-Nearest-Neighbor (KNN) and Range queries. We also propose a new load-balanced indexing algorithm and evaluate it using our Java based simulator. Our results show that this P2P design ensures load-balancing and guarantees logarithmic number of hops for query processing. Our system is extensible to be used with all types of multi-dimensional feature data and it can also be employed as the main indexing scheme of a multipurpose recommendation system. / Graduate
864

Localization of autonomous ground vehicles in dense urban environments

Himstedt, Marian 03 March 2014 (has links) (PDF)
The localization of autonomous ground vehicles in dense urban environments poses a challenge. Applications in classical outdoor robotics rely on the availability of GPS systems in order to estimate the position. However, the presence of complex building structures in dense urban environments hampers a reliable localization based on GPS. Alternative approaches have to be applied In order to tackle this problem. This thesis proposes an approach which combines observations of a single perspective camera and odometry in a probabilistic framework. In particular, the localization in the space of appearance is addressed. First, a topological map of reference places in the environment is built. Each reference place is associated with a set of visual features. A feature selection is carried out in order to obtain distinctive reference places. The topological map is extended to a hybrid representation by the use of metric information from Geographic Information Systems (GIS) and satellite images. The localization is solved in terms of the recognition of reference places. A particle lter implementation incorporating this and the vehicle's odometry is presented. The proposed system is evaluated based on multiple experiments in exemplary urban environments characterized by high building structures and a multitude of dynamic objects.
865

Nesąžiningos konkurencijos kvalifikavimo problemos / Evaluation problems of unfair competition

Bendorienė, Auksė 28 January 2014 (has links)
Šiame baigiamajame magistro darbe, analizuojant Lietuvos teisės aktus, mokslinę literatūrą bei Lietuvos ir ETT praktikoje suformuotas su darbo tema susijusias atitinkamų klausimų ir teisės aktų nuostatų aiškinimo ir taikymo taisykles, atskleidžiamas nesąžiningos konkurencijos sąvokos turinys ir įvardijami atskirų nesąžiningos konkurencijos atvejų kvalifikavimo ypatumai. Šio tyrimo tikslas – išanalizuoti nesąžiningos konkurencijos reglamentavimo Lietuvos konkurencijos teisėje ypatumus bei nustatyti taikymo praktikoje problemas – pasiektas įgyvendinus tokius uždavinius: pirmiausia, išanalizavus mokslinę literatūrą, Lietuvos teismų praktiką, Lietuvos Respublikos teisės aktus, aptariančius nesąžiningos konkurencijos sampratą, atskleidžiant jos turinį; po to yra nustatoma nesąžiningos konkurencijos instituto Lietuvos teisės aktuose įtvirtinimo raida ir reikšmė, aptarti pagrindiniai unifikavimo su ES teise aspektai; ir galiausiai identifikuojami nesąžiningos konkurencijos atvejų kvalifikavimo ypatumai, įvertinamas nesąžiningą konkurenciją reglamentuojančių teisės normų veiksmingumas bei atskleidžiami teisinio reguliavimo netikslumai ir dėl to iškylančios problemos. Magistrinio baigiamojo darbo temai atskleisti buvo naudojami loginis-analitinis, lingvistinis, lyginamasis, istorinis, sisteminės analizės metodai, kurių pagalba darbo tema buvo išanalizuota, pateiktos išvados bei įvertintas hipotezės teisingumas. Remiantis padarytomis išvadomis, manytina, jog darbo hipotezė – „Siekiant... [toliau žr. visą tekstą] / In this master thesis the concept of unfair competition is revealed and qualification features of individual cases of unfair competition are presented by analyzing the Lithuanian legislation, scientific and legal literature as well as analysing Lithuanian and ECJ juridictions’ legal acts, legislation and legal practice. The objective of this master thesis - to analyze the regulation of unfair competition in Lithuanian’s competition law and to determine practical application problems- has been achieved through the following tasks. First, scientific literature, legal practice, legal acts of the Republic of Lithuania discussing the concept of unfair competition and its content are analyzed, then the development and the importance of unfair competence institute setting in Lithuanian legal acts is determined, the main aspects of unification with EU law are discussed, finally, classification features of cases of unfair competition are identified and the efficiency of unfair competition legislation is evaluated, also regulatory uncertainties and the problems it may cause are indicated. Logical and analytical, linguistic, comparative, historical, systematic analysis methods were used to analyze the topic, present the conclusions and to find out if the hypothesis was right. On the basis of the thesis conclusions, it must be held that the hypothesis - In order to make a proper legal classification of actions of unfair competition, in practice encounter problems due to lack of a clear... [to full text]
866

Mathcad Prime 1.0 "Die Zukunft hat begonnen"

Jordan, Dirk 11 May 2011 (has links) (PDF)
In diesem Vortrag wird Mathcad Prime 1.0 gezeigt. Es wird ein Ausblick auf Anwendungsmöglichkeiten (Best Practices) gegeben und auch ein Blick auf die Mathcad Roadmap geworfen.
867

Human Action Recognition In Video Data For Surveillance Applications

Gurrapu, Chaitanya January 2004 (has links)
Detecting human actions using a camera has many possible applications in the security industry. When a human performs an action, his/her body goes through a signature sequence of poses. To detect these pose changes and hence the activities performed, a pattern recogniser needs to be built into the video system. Due to the temporal nature of the patterns, Hidden Markov Models (HMM), used extensively in speech recognition, were investigated. Initially a gesture recognition system was built using novel features. These features were obtained by approximating the contour of the foreground object with a polygon and extracting the polygon's vertices. A Gaussian Mixture Model (GMM) was fit to the vertices obtained from a few frames and the parameters of the GMM itself were used as features for the HMM. A more practical activity detection system using a more sophisticated foreground segmentation algorithm immune to varying lighting conditions and permanent changes to the foreground was then built. The foreground segmentation algorithm models each of the pixel values using clusters and continually uses incoming pixels to update the cluster parameters. Cast shadows were identified and removed by assuming that shadow regions were less likely to produce strong edges in the image than real objects and that this likelihood further decreases after colour segmentation. Colour segmentation itself was performed by clustering together pixel values in the feature space using a gradient ascent algorithm called mean shift. More robust features in the form of mesh features were also obtained by dividing the bounding box of the binarised object into grid elements and calculating the ratio of foreground to background pixels in each of the grid elements. These features were vector quantized to reduce their dimensionality and the resulting symbols presented as features to the HMM to achieve a recognition rate of 62% for an event involving a person writing on a white board. The recognition rate increased to 80% for the &quotseen" person sequences, i.e. the sequences of the person used to train the models. With a fixed lighting position, the lack of a shadow removal subsystem improved the detection rate. This is because of the consistent profile of the shadows in both the training and testing sequences due to the fixed lighting positions. Even with a lower recognition rate, the shadow removal subsystem was considered an indispensable part of a practical, generic surveillance system.
868

Significance, the vessel and the domestic

Brown, Sandra Lois, School of Design, UNSW January 2004 (has links)
Throughout history, people have made or acquired vessels from which to sip their favourite beverage. In the contemporary domestic setting, households frequently accumulate multiples of the same type of object in numbers that are considerably greater than is necessary and practical for use alone. Of these many objects there are often individual pieces that have special significance for the owner or user. Some are so valued that they may even be removed and set aside because of their perceived importance. The research was initiated by a previous study of tea drinking vessels coupled with a desire, as an object maker and collector, to find out why people have special items that they designate as personally important. The aim was to identify how significance could be recognised in specific objects and whether the notion that a group of features used to gauge such objects could be conveyed into studio based work. The research outcomes are evidenced in a text-based document (which articulates the theoretical and empirical elements of the enquiry) and a body of creative studio work developed in response to aspects of the investigation. The document encompasses two components of the study. The first references material from the fields of museum and cultural studies, pivotal in focusing the enquiry. This contributed to the compilation of a general and speculative inventory of qualities that might pertain to objects deemed ???significant???. During these early investigations it became evident that a more in depth and contemporary analysis of significant drinking vessels, their owners and/or users was required. A Survey Questionnaire regarding personal use and special drinking vessels preceded a series of Interviews with a selected group of Australia curators, artists, academics and collectors who discussed and analysed their association with a personally significant drinking vessel. Subsequently, the content of these interviews became central to the focus of the research and outcomes. The research isolates a number of attributes that are commonly identified in objects that, whatever their condition, are deemed ???significant???. These describe the maker, usage, ownership, association and historical context. The perceived value or worth of the object for its owner, is recognised as a consequence of significance and declares the object as distinctive. This outcome is clearly validated by the interviews. The studio work develops from the fusion of personal narrative that has been enhanced by findings of the research. In particular, it references the cherished object, most especially those pieces that have been retained despite the ravages of time and use. The resulting work was exhibited as Trace Elements ??? Marking Time: Significance, the Vessel and the Domestic at Kudos Gallery, Paddington in April 2004.
869

Αναγνώριση ομιλητή και ομιλίας με χρήση κυματιδίων

Σιαφαρίκας, Μιχαήλ 06 September 2010 (has links)
Σκοπός της παρούσας διατριβής είναι η εκμετάλλευση των κυματιδίων με σκοπό την βελτίωση της απόδοσης συστημάτων αναγνώρισης ομιλητή και ομιλίας. Στα πλαίσια αυτά, εισάγονται τέσσερις νέοι τρόποι παραμετροποίησης του σήματος ομιλίας: (1) Η πρώτη μέθοδος προσαρμόζει την ανάλυση συχνότητας των πακέτων κυματιδίων για την προσέγγιση της ψυχοακουστικής επίδρασης των κρίσιμων ζωνών του ακουστικού συστήματος ενσωματώνοντας τις τελευταίες εξελίξεις για τον υπολογισμό τους. (2) Η δεύτερη μέθοδος εισάγει μια επέκταση του μετασχηματισμού πακέτων κυματιδίων, τον επικαλυπτόμενο μετασχηματισμό πακέτων κυματιδίων, ο οποίος χρησιμοποιείται για να δοθεί έμφαση στις περιοχές αλλαγής των κρίσιμων ζωνών από μια μικρότερη σε μια μεγαλύτερη τιμή. (3) Η τρίτη μέθοδος αξιολογεί τη συνεισφορά μη επικαλυπτόμενων ζωνών συχνοτήτων στην αναγνώριση ομιλητή και κατασκευάζεται ανάλογα ένας μετασχηματισμός πακέτων κυματιδίων ο οποίος προσαρμόζει την συχνοτική του ανάλυση σύμφωνα με την απόδοση κάθε μίας από τις ζώνες. (4) Η τέταρτη μέθοδος επιλέγει τη βέλτιστη βάση από το σύνολο των μετασχηματισμών που είναι διαθέσιμοι με τα πακέτα κυματιδίων με εφαρμογή την αναγνώριση ομιλητή και κριτήριο το μέτρο EER. Οι παραπάνω τέσσερις τρόποι παραμετροποίησης του σήματος ομιλίας αξιολογήθηκαν με το σύστημα αναγνώρισης ομιλητή WCL-1 του εργαστηρίου ενσύρματης τηλεπικοινωνίας του Πανεπιστημίου Πατρών στις βάσεις δεδομένων POLYCOST και NIST και αποδείχθηκε η ανωτερότητά τους τόσο σε σχέση με προηγούμενες μεθόδους των κυματιδίων όσο και σε σχέση με ευρέως χρησιμοποιούμενες παραμέτρους ομιλίας, όπως οι παράμετροι cepstral με βάση την κλίμακα mel (MFCC). Επιπλέον, στη διατριβή αναλύονται οι ιδιότητες των σημαντικότερων συναρτήσεων κυματιδίων, επιλέγεται η βέλτιστη για την αναπαράσταση του σήματος ομιλίας και πιστοποιείται στην πράξη αυτή η επιλογή. Τέλος, οι δύο πρώτες από τις προαναφερόμενες μεθόδους παραμετροποίησης τροποποιήθηκαν και επεκτάθηκαν κατάλληλα για την εφαρμογή στην αναγνώριση ομιλίας όπου αξιολογήθηκαν και διαπιστώθηκε η υπεροχή τους έναντι παραδοσιακών και ευρέως διαδεδομένων μεθόδων παραμετροποίησης του σήματος ομιλίας που στηρίζονται στον μετασχηματισμό Fourier. Το κύριο συμπέρασμα που προέκυψε από τη παρούσα διδακτορική διατριβή είναι ότι τα κυματίδια και συγκεκριμένα τα πακέτα κυματιδίων είναι δυνατόν να χρησιμοποιηθούν με επιτυχία στη βελτίωση της απόδοσης συστημάτων αναγνώρισης ομιλητή και ομιλίας. / The main goal of the present thesis is the exploitation of wavelets for the optimization of speaker and speech recognition systems performance. In this context, four new speech parameterization methods are introduced: (1) The first method adapts the frequency resolution of wavelet packet transform to the critical bandwidth of auditory filters incorporating the recent advances for their estimation. (2) The second method introduces a generalization of wavelet packet transform, named overlapping wavelet packet transform, which emphasizes those frequency sub-bands that critical bandwidth changes from a finer to a coarser value. (3) The third method evaluates the contribution of each one of eight non-overlapping frequency sub-bands, that the Nyquist interval is divided, to the speaker recognition task and a wavelet packet transform is constructed which adapts its frequency resolution according to the performance of each sub-band. (4) The fourth method introduces a new technique for seeking and selecting the best basis among all wavelet packet transforms available in the speaker recognition task taking as criterion the EER. The aforementioned four speech signal parameterizations were evaluated on the speaker verification system WCL-1 of Wire Communications Laboratory, University of Patras, utilizing the speaker recognition corpora POLYCOST and NIST and their superiority was proven over previous wavelet-based parameterizations as well as the widely used Mel Frequency Cepstral Coefficients (MFCC). Among the four proposed methods, it was proven that the second parameterization technique exhibited the best performance. Furthermore, the most important wavelet properties are thoroughly analyzed, the optimal is selected for the representation of the speech signal and this choice is experimentally verified. Finally, the first two parameterization methods were further modified and extended appropriately for application on the speech recognition task where their superiority was proven over traditionally and widely used speech parameterization techniques based on Fourier transform. The main conclusion that resulted in the present doctoral thesis is that wavelets and specifically wavelet packet transforms can be used successfully for the tasks of speaker and speech recognition.
870

Οργάνωση βάσεων εικόνων βάσει περιγράμματος : εφαρμογή σε φύλλα

Φωτοπούλου, Φωτεινή 16 June 2011 (has links)
Το αντικείμενο της μελέτης αυτής είναι η οργάνωση (ταξινόμηση, αναγνώριση, ανάκτηση κλπ.) βάσεων που περιλαμβάνουν εικόνες (φωτογραφίες) φύλλων δένδρων. Η οργάνωση βασίζεται στο σχήμα των φύλλων και περιλαμβάνει διάφορα στάδια. Το πρώτο στάδιο είναι η εξαγωγή του περιγράμματος και γίνεται με διαδικασίες επεξεργασίας εικόνας που περιλαμβάνουν τεχνικές ομαδοποίησης και κατάτμησης. Από το περίγραμμα του φύλλου εξάγονται χαρακτηριστικά που δίνουν την δυνατότητα αξιόπιστης περιγραφής κάθε φύλλου. Μελετήθηκαν στη διατριβή αυτή οι παρακάτω γνωστές μέθοδοι: Centroid Contour Distance, Angle code (histogram), Chain Code Fourier Descriptors. Προτάθηκαν επίσης και καινούριες μέθοδοι: Pecstrum (pattern spectrum), Multidimension Sequence Similarity Measure (MSSM). Οι παραπάνω μέθοδοι υλοποιήθηκαν. Παράχθηκε κατάλληλο λογισμικό και εφαρμόσθηκαν σε μία βάση εικόνων φύλλων επιλεγμένη από το διαδίκτυο. Η αξιολόγηση των μεθόδων έγινε μέσα από έλεγχο της συνολικής ακρίβειας κατηγοριοποίησης (με τον confusion matrix). H μέθοδος MSSM έδωσε τα καλύτερα αποτελέσματα. Μία οπτική αξιολόγηση έγινε σε αναπαράσταση 2 διαστάσεων (biplot) μέσα απο διαδικασία Multidimensional Scaling. / The objective of this thesis is the leaf images data base organization (i.e classification, recognition, retrieval etc.). The database organization is based on the leaf shape and is accomplished in a few stages. The contour recognition and recording consist the first stage and is performed with image processing operations namely clustering and segmentation. From the leaf contour several features are extracted appropriate for a reliable description of each leaf type. The following well known techniques were studied in this thesis: Centroid Contour Distance, Angle code (histogram), Chain Code, Fourier Descriptors. Two new metods were also proposed: Pecstrum (pattern spectrum), Multidimension Sequence Similarity Measure. In the experimental study appropriate software was produced to realize all the above methods which was applied to the leaf data base downloaded from internet. The overall evaluation of the methods was done by means of the classification in precision and using the confusion matrix. Best results were produced by the MSSM method.

Page generated in 0.0502 seconds