• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 499
  • 201
  • 111
  • 59
  • 55
  • 39
  • 38
  • 28
  • 19
  • 16
  • 14
  • 13
  • 8
  • 6
  • 6
  • Tagged with
  • 1288
  • 142
  • 120
  • 120
  • 116
  • 112
  • 108
  • 106
  • 93
  • 85
  • 80
  • 80
  • 73
  • 70
  • 67
  • 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.
371

Weakly Trained Parallel Classifier and CoLBP Features for Frontal Face Detection in Surveillance Applications

Louis, Wael 10 January 2011 (has links)
Face detection in video sequence is becoming popular in surveillance applications. The trade-off between obtaining discriminative features to achieve accurate detection versus computational overhead of extracting these features, which affects the classification speed, is a persistent problem. Two ideas are introduced to increase the features’ discriminative power. These ideas are used to implement two frontal face detectors examined on a 2D low-resolution surveillance sequence. First contribution is the parallel classifier. High discriminative power features are achieved by fusing the decision from two different features trained classifiers where each type of the features targets different image structure. Accurate and fast to train classifier is achieved. Co-occurrence of Local Binary Patterns (CoLBP) features is proposed, the pixels of the image are targeted. CoLBP features find the joint probability of multiple LBP features. These features have computationally efficient feature extraction and provide high discriminative features; hence, accurate detection is achieved.
372

Case Study of Feature-Oriented Requirements Modelling, Applied to an Online Trading System

Krulec, Ana 12 1900 (has links)
The Feature-Oriented Requirements Modelling (FORM) combines the requirement engineering style structuring of requirements documents with the feature-orientation of the Feature Oriented Software Development, resulting in a feature-oriented model of the functional requirements of a system-under-development (SUD). A feature is a distinguishable unit of added value to the SUD. The objectives of FORM are to model features as independent modules, to allow the addition of new features with minimal changes to the existing features, and to enable automatic generation and checking of properties like correctness, consistency, and non-determinism. FORM structures requirements into three models: a domain model, a collection of behavioural models, and a collection of functional models. A feature is modelled by a distinct behavioural model. This dissertation evaluates FORM by applying it to a new application that can be thought of in terms of features, namely an online trading system (OTS) that receives requests from customers about buying or selling securities on a stock market. The OTS offers variability in terms of the types of orders that customers can request, (e.g. market order, limit order and stop order). The case study revealed six deficiencies of the FORM notation, three of which were easily overcome. The dissertation presents the results of the case study, resolutions to three of the six deficiencies, and an outline of an approach to resolve the other three deficiencies.
373

Mold Feature Recognition using Accessibility Analysis for Automated Design of Core, Cavity, and Side-Cores and Tool-Path Generation of Mold Segments

Bassi, Rajnish January 2012 (has links)
Injection molding is widely used to manufacture plastic parts with good surface finish, dimensional stability and low cost. The common examples of parts manufactured by injection molding include toys, utensils, and casings of various electronic products. The process of mold design to generate these complex shapes is iterative and time consuming, and requires great expertise in the field. As a result, a significant amount of the final product cost can be attributed to the expenses incurred during the product’s design. After designing the mold segments, it is necessary to machine these segments with minimum cost using an efficient tool-path. The tool-path planning process also adds to the overall mold cost. The process of injection molding can be simplified and made to be more cost effective if the processes of mold design and tool-path generation can be automated. This work focuses on the automation of mold design from a given part design and the automation of tool-path generation for manufacturing mold segments. The hypothesis examined in this thesis is that the automatic identification of mold features can reduce the human efforts required to design molds. It is further hypothesised that the human effort required in many downstream processes such as mold component machining can also be reduced with algorithmic automation of otherwise time consuming decisions. Automatic design of dies and molds begins with the part design being provided as a solid model. The solid model of a part is a database of its geometry and topology. The automatic mold design process uses this database to identify an undercut-free parting direction, for recognition of mold features and identification of parting lines for a given parting direction, and for generation of entities such as parting surfaces, core, cavity and side-cores. The methods presented in this work are analytical in nature and work with the extended set of part topologies and geometries unlike those found in the literature. Moreover, the methods do not require discretizing the part geometry to design its mold segments, unlike those found in the literature that result in losing the part definition. Once the mold features are recognized and parting lines are defined, core, cavity and side-cores are generated. This work presents algorithms that recognize the entities in the part solid model that contribute to the design of the core, cavity and side-cores, extract the entities, and use them in the design of these elements. The developed algorithms are demonstrated on a variety of parts that cover a wide range of features. The work also presents a method for automatic tool-path generation that takes the designed core/cavity and produces a multi-stage tool-path to machine it from raw stock. The tool-path generation process begins by determining tool-path profiles and tool positions for the rough machining of the part in layers. Typically roughing is done with large aggressive tools to reduce the machining time; and roughing leaves uncut material. After generating a roughing tool-path for each layer, the machining is simulated and the areas left uncut are identified to generate a clean-up tool-path for smaller sized tools. The tool-path planning is demonstrated using a part having obstacles within the machining region. The simulated machining is presented in this work. This work extends the accessibility analysis by retaining the topology information and using it to recognize a larger domain of features including intersecting features, filling a void in the literature regarding a method that could recognize complex intersecting features during an automated mold design process. Using this information, a larger variety of new mold intersecting features are classified and recognized in this approach. The second major contribution of the work was to demonstrate that the downstream operations can also benefit from algorithmic decision making. This is shown by automatically generating roughing and clean-up tool-paths, while reducing the machining time by machining only those areas that have uncut material. The algorithm can handle cavities with obstacles in them. The methodology has been tested on a number of parts.
374

Perceptions Of Prospective Computer Teachers Toward The Use Of Computer Games With Educational Features In Education

Can, Gulfidan 01 July 2003 (has links) (PDF)
This study investigates the perceptions of prospective computer teachers, who have been studying at the Computer Education and Instructional Technology (CEIT) departments of four different universities, toward the use of computer games with educational features in education. It also examines the future plans of the participants regarding the use of computer games with educational features in their courses or in learning environments that they will design and it explores the participants&rsquo / computer game playing characteristics as well. The subjects of this study were 116 students from the Computer Education and Instructional Technology departments of four universities: Ankara, Gazi, Hacettepe and the Middle East Technical University. The data were collected through a questionnaire and interviews. The data were analyzed by using descriptive statistics and qualitative analysis methods. This study reveals that the prospective computer teachers who participated in this study have positive perceptions toward the use of computer games with educational features in education. Moreover, most of the participants plan to use such games in their future professions according to their responses. However, it is revealed that participants also have doubts about some issues regarding the use of such games in education, although this is a rare case.
375

New Interpretations Of Domestic Space And Life: The Emergence Of Apartment Buildings In Nineteenth Century Istanbul

Gozubuyuk Melek, Dilsad 01 December 2004 (has links) (PDF)
This thesis attempts to study the architectural and the social changes brought by the multi-story apartment buildings which emerged in the nineteenth century istanbul, in especially Galata-Pera region. A brief introduction to the modernization attempts of the Ottoman Empire, and also to the traditional dwellings and daily life of the Ottoman households before the nineteenth century constitute the first sections of the study. The architectural and the urban developments such as the new building regulations, architectural styles and building types as well as the social and cultural changes that brought new cultural habits and life styles in the modernization period, are also studied in this context. A group of apartments with different plans, size and locations are chosen as a sample so as to point out and discuss the layout of the constituent spaces like the halls, foyers, corridors, substantial rooms and wet spaces. Respectively the changing meaning of the &lsquo / house&rsquo / and daily life are also pointed out. In relation to these, facade organizations, plans, functional and spatial features and the privacy of spaces in the sample apartment buildings and their flats, and the daily life and the privacy of the apartment residents are studied and discussed in comparison to the traditional Ottoman house and the contemporary Parisian apartments to present a comparative perspective. Consequently, &lsquo / similarities&rsquo / , &lsquo / differences&rsquo / , and &lsquo / innovations&rsquo / concerning the nineteenth century istanbul apartments are discussed and listed at the end of the thesis. Several tables which are designed to contribute to the arguments presented in the study are also added to the thesis.
376

Urban Balconies As Public Open Areas A Case Study: Bursa

Ozaslan, Aslihan 01 December 2005 (has links) (PDF)
The need for the public areas within urban environments is increasing day by day. This thesis focuses on urban balconies as one of the important element of public open areas. Their historical backgrounds, contribution to the cities, categorization and exemplification form important topics for explaining the concept. The study also searches the important natural features that effect the urban development of Bursa and questions the place of urban balconies between them. While explaining the past and the present situations, types and the usages of urban balconies&amp / #8217 / of Bursa / this thesis emphasizes their existing but neglected qualitative and quantitative values, that have the potential to play an important role for the physical shaping of the city so as the formation of urban image. Related to this, also the importance of the revitalization of the urban balconies as public open areas takes part in this study. Key Words: Urban Balconies, Vista Points, Topographical Features, Public Open Areas, Bursa.
377

Movement behaviour and distribution of forest songbirds in an expanding urban landscape.

Tremblay, Marie Anne 11 1900 (has links)
Urbanization is viewed as a major threat to global biodiversity because of its role in the loss and fragmentation of low-lying, productive habitats associated with coastal plains and river valleys. My study examines the effects of urbanization on the movements and distribution of songbirds in Calgary, Alberta, Canada. I conducted playback and translocation experiments to assess the permeability of small-scale (e.g. transportation corridors, rivers) and large-scale (e.g. multi-lane expressways, areas of urban development) features of the urban landscape, respectively. I then used these empirical data to parameterize spatially explicit models and determine functional landscape connectivity across the study area. Finally, using point surveys conducted at 183 sites across the urban matrix, I examined the role of land cover type, local vegetation characteristics, landscape-level forest cover, and isolation from natural features on the distribution of songbirds. In 563 playback trials involving the responses of 2241 birds, I found that the size of the gap in vegetation was the most important determinant of movement across linear features; the likelihood of movement sharply decreasing as the gap in vegetation exceeded 30 m. The results of 176 translocation trials provided further evidence of the barrier effect of gaps. Multiple gaps, in particular, constrained the movements of both yellow warblers (Dendroica petechia) and black-capped chickadees (Poecile atricapillus). The bird surveys revealed that natural forest stands played a critical role in sustaining regional avian diversity in the study area. Moreover, functional distance to the nearest forested natural area or water body often explained more variation in the probability of occurrence of focal species than straight-line distance, suggesting that barriers identified from the permeability experiments may have affected not only the movements of songbirds but their settlement patterns as well. Taken together, my results suggest that preserving a functionally connected network of natural areas is vital to conserving avian biodiversity in cities. My research describes novel methodologies for characterizing the composition and configuration of highly heterogeneous and fragmented landscapes. It also provides a unique examination of the link between the movement behaviour of individual birds and population-level distribution patterns within this context. / Ecology
378

Virus recognition in electron microscope images using higher order spectral features

Ong, Hannah Chien Leing January 2006 (has links)
Virus recognition by visual examination of electron microscope (EM) images is time consuming and requires highly trained and experienced medical specialists. For these reasons, it is not suitable for screening large numbers of specimens. The objective of this research was to develop a reliable and robust pattern recognition system that could be trained to detect and classify different types of viruses from two-dimensional images obtained from an EM. This research evaluated the use of radial spectra of higher order spectral invariants to capture variations in textures and differences in symmetries of different types of viruses in EM images. The technique exploits invariant properties of the higher order spectral features, statistical techniques of feature averaging, and soft decision fusion in a unique manner applicable to the problem when a large number of particles were available for recognition, but were not easily registered on an individual basis due to the low signal to noise ratio. Experimental evaluations were carried out using EM images of viruses, and a high statistical reliability with low misclassification rates was obtained, showing that higher order spectral features are effective in classifying viruses from digitized electron micrographs. With the use of digital imaging in electron microscopes, this method can be fully automated.
379

Automatic emotion recognition: an investigation of acoustic and prosodic parameters

Sethu, Vidhyasaharan , Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2009 (has links)
An essential step to achieving human-machine speech communication with the naturalness of communication between humans is developing a machine that is capable of recognising emotions based on speech. This thesis presents research addressing this problem, by making use of acoustic and prosodic information. At a feature level, novel group delay and weighted frequency features are proposed. The group delay features are shown to emphasise information pertaining to formant bandwidths and are shown to be indicative of emotions. The weighted frequency feature, based on the recently introduced empirical mode decomposition, is proposed as a compact representation of the spectral energy distribution and is shown to outperform other estimates of energy distribution. Feature level comparisons suggest that detailed spectral measures are very indicative of emotions while exhibiting greater speaker specificity. Moreover, it is shown that all features are characteristic of the speaker and require some of sort of normalisation prior to use in a multi-speaker situation. A novel technique for normalising speaker-specific variability in features is proposed, which leads to significant improvements in the performances of systems trained and tested on data from different speakers. This technique is also used to investigate the amount of speaker-specific variability in different features. A preliminary study of phonetic variability suggests that phoneme specific traits are not modelled by the emotion models and that speaker variability is a more significant problem in the investigated setup. Finally, a novel approach to emotion modelling that takes into account temporal variations of speech parameters is analysed. An explicit model of the glottal spectrum is incorporated into the framework of the traditional source-filter model, and the parameters of this combined model are used to characterise speech signals. An automatic emotion recognition system that takes into account the shape of the contours of these parameters as they vary with time is shown to outperform a system that models only the parameter distributions. The novel approach is also empirically shown to be on par with human emotion classification performance.
380

Analysis of dynamic angle of gait and radiographic features in subjects with hallux valgus

Taranto, Julie January 2005 (has links)
[Truncated abstract] Hallux valgus (HV) is one of the most common foot deformities encountered in clinical practice. This complex deformity primarily affects the first metatarsophalangeal joint (MPJ), leading to altered foot structure and function. By virtue of the lateral displacement of the hallux on the first metatarsal, HV has the potential to influence adjacent joints of the foot. In doing so, function of the foot may be altered, and clinically this may result in abduction of the foot during the stance phase of gait. However the relationship between an abducted angle of gait (AOG) and HV has never been substantially examined. The purpose of this study is to investigate the relationship between HV and AOG, and determine if specific radiographic features are associated with the deformity or with a particular AOG. Such information would assist in understanding aetiological factors and the effects of intervention to treat the deformity ... Length and elevation of the first metatarsal were associated in subjects with HV, implying that length of the metatarsal may be related to whether or not it becomes elevated (R: 0.50, CI: 0.21, 0.71, P< 0.05). Similarly, an association was found between length of the first metatarsal and the amount of first MPJ dorsiflexion, suggesting perhaps length of the metatarsal has implications for first MPJ range of motion (R: -0.37, CI: -0.62, -0.04, P<0.05). However the amount of first MPJ dorsiflexion did not influence the AOG in HV subjects when compared to the control group. First MPJ dorsiflexion was also associated with the first intermetatarsal angle. Interestingly, the HV group alone did not show an association between the hallux abductus angle and the first intermetatarsal angle. The findings of this study are contrary to those suspected in clinical practice and alluded to in the literature. Despite the documented support for the biomechanical causes of HV, an abducted AOG was not significantly different in HV subjects when compared to controls. Possible explanations may have related to limitations of the present study including the size and gender demographics of the sample population, and greater variability in normal AOG ranges than reported in the literature. The present study indicated a possible need to gather information regarding foot dominance and leg length; factors extrinsic to the foot capable of influencing transverse plane orientation of the foot; and, the influence of symptoms and subsequent compensatory mechanisms adopted during gait.

Page generated in 0.0407 seconds