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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.
11

Five contributions to econometric theory and the econometrics of ultra-high-frequency data

Meitz, Mika January 2006 (has links)
No description available.
12

Models For Estimating Construction Duration: An Application For Selected Buildings On The Metu Campus

Odabasi, Elvan 01 July 2009 (has links) (PDF)
The duration of construction of a project depends on many factors, such as: cost, location, site characteristics, procurement methods, area of construction, footprint of the building and its height, etc. It is very important to be able to predict these durations accurately in order to successfully complete a project on time. Various construction duration estimation tools have been developed to make accurate predictions, as &ldquo / time is money.&rdquo / The main objective of this study was to develop a model that can be used to predict the construction duration of a project in a reliable and practical way. Contractors can thus use a project&#039 / s characteristics, as given in the tender documents, to estimate the actual amount time it would take them to complete the construction works. In this study, factors affecting the duration of a construction project and models for estimating construction durations were investigated. Within this framework, duration estimation models such as / Bromilow&rsquo / s Time-Cost (BTC) Model and Building Cost Information Service (BCIS) Model were used while Simple Linear Regression (SLR) and Multiple Linear Regression (MLR) analyses were conducted on data related to seven case study buildings that are situated at the Middle East Technical University (METU) campus in Ankara. This data was obtained from the Department of Construction and Technical Works (DCTW) at METU. The closeness in estimation of the regression analyses was investigated and finally an MLR model was obtained which was based on two parameters / the area of the building and the area of its fa&ccedil / ade. On the other hand, as opposed to studies reported in literature, the effect of cost on duration was not seen to be significant.
13

Phoneme duration modelling for speaker verification

Van Heerden, Charl Johannes 26 June 2009 (has links)
Higher-level features are considered to be a potential remedy against transmission line and cross-channel degradations, currently some of the biggest problems associated with speaker verification. Phoneme durations in particular are not altered by these factors; thus a robust duration model will be a particularly useful addition to traditional cepstral based speaker verification systems. In this dissertation we investigate the feasibility of phoneme durations as a feature for speaker verification. Simple speaker specific triphone duration models are created to statistically represent the phoneme durations. Durations are obtained from an automatic hidden Markov model (HMM) based automatic speech recognition system and are modeled using single mixture Gaussian distributions. These models are applied in a speaker verification system (trained and tested on the YOHO corpus) and found to be a useful feature, even when used in isolation. When fused with acoustic features, verification performance increases significantly. A novel speech rate normalization technique is developed in order to remove some of the inherent intra-speaker variability (due to differing speech rates). Speech rate variability has a negative impact on both speaker verification and automatic speech recognition. Although the duration modelling seems to benefit only slightly from this procedure, the fused system performance improvement is substantial. Other factors known to influence the duration of phonemes are incorporated into the duration model. Utterance final lengthening is known be a consistent effect and thus “position in sentence” is modeled. “Position in word” is also modeled since triphones do not provide enough contextual information. This is found to improve performance since some vowels’ duration are particularly sensitive to its position in the word. Data scarcity becomes a problem when building speaker specific duration models. By using information from available data, unknown durations can be predicted in an attempt to overcome the data scarcity problem. To this end we develop a novel approach to predict unknown phoneme durations from the values of known phoneme durations for a particular speaker, based on the maximum likelihood criterion. This model is based on the observation that phonemes from the same broad phonetic class tend to co-vary strongly, but that there is also significant cross-class correlations. This approach is tested on the TIMIT corpus and found to be more accurate than using back-off techniques. / Dissertation (MEng)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted
14

Offshore Wind Turbine Transportation & Installation Analyses Planning Optimal Marine Operations for Offshore Wind Projects

Uraz, Emre January 2011 (has links)
Transportation and installation of offshore wind turbines (Tower, Nacelle and Rotor) is a complete process conducted over several phases, usually in sequence. There are several factors that can turn this process into a challenge. These factors can either be due to offshore site conditions or the technical limitations of the installation vessels. Each project has its own characteristic parameters and requires a unique optimum solution. This paper identifies the dynamics of the installation process and analyzes the effects of each phase on the progression of events.The challenges in wind turbine installations due to offshore environment were investigated, the effects of each were explained and their significances were stressed. Special installation vessels were examined and their technical specifications were analyzed in terms of working conditions, dimensions, service performances, and crane capacities as well as projecting future design trends. Several offshore wind farm projects were analyzed; their installation methods were specified, and compared to each other to determine advantages and disadvantages of different pre-assembly concepts. The durations of the sub-phases of the process were defined in terms of different variables such as site conditions and individual vessel performance. These definitions were used for making time estimations, and conducting further analyses regarding the effects of different site specific parameters on the overall project duration.In conclusion, this study considered the main operation parameters in an offshore wind turbine installation context: the benefits and drawbacks of different pre-assembly methods were researched and evaluated resulting in new knowledge and a productive contribution for optimizing “the offshore turbine transportation and installation process”, based on actual time usage.
15

Perturbation de la production de la parole suite à une opération de la glande thyroïde / Perturbation of speech production as a result of thyroid gland surgery

Fauth, Camille 04 December 2012 (has links)
L’objectif de ce travail, mené en partenariat avec le Département de Chirurgie Oncologique du Centre Paul Strauss à Strasbourg, est d’évaluer les conséquences d’une chirurgie thyroïdienne sur la voix des patients, afin de déceler les différentes perturbations qu’entraîne cette opération chirurgicale, et de mettre au jour les possibles stratégies de compensation ou de réajustements que le patient peut mettre en place, seul ou à l’aide d’une rééducation orthophonique ; il s’agit d’une étude longitudinale. L’évaluation reposait sur l’analyse de signaux acoustiques, à partir desquels une quantité importante d’indices relatifs à la qualité vocale, mais aussi aux comportements articulatoires des locuteurs, a pu être extraite. La production de voyelles soutenues a permis de conduire deux études spectrales. L’étude spatio-temporelle a été rendue possible grâce à l’analyse de logatomes, et plus précisément de séquences VCV. Nous avons mené trois expériences sur le plan acoustique. La première expérience traite des caractéristiques spectrales de la voix de patients ayant subi une thyroïdectomie et ne présentant pas d’immobilité laryngée. La deuxième étude est menée à partir des caractéristiques spectrales de la voix de locuteurs présentant une immobilité laryngée post-thyroïdectomie. Enfin, notre dernière expérience a pour objet, l’étude des caractéristiques spatio-temporelles de la voix de locuteurs qui ont subi une thyroïdectomie et présentant une immobilité laryngée. L’interprétation articulatoire, effectuée à partir des données acoustiques, révèle des perturbations aussi bien des gestes glottiques que des gestes supraglottiques, avec des stratégies de réajustements variables suivant les patients. La conception d’une « cible », comme espace de contrôle pour la réalisation de possibles articulatoires et acoustiques perceptivement acceptables, semble particulièrement pertinente ici, dans la mesure où les locuteurs pathologiques réorganisent leurs productions selon leurs propres contraintes physiologiques et anatomiques, provoquées par leur pathologie. / The aim of this study, conducted in partnership with the Department of Surgical Oncology, Centre Paul Strauss in Strasbourg, is to assess the consequences of thyroid surgery on the voice of patients, in order to identify the various perturbations caused by this surgery, and also to reveal possible compensatory strategies or readjustments that the patient may develop, alone or with speech therapy; this is a longitudinal study. The assessment was based on the analysis of acoustic signals, from which a large amount of cues related to voice quality, but also to articulatory behaviour of speakers was extracted. Production of sustained vowels allowed carrying out two spectral studies. The spatiotemporal study was made possible through the analysis of nonsense words, and more specifically through VCV sequences. We conducted three experiments on the acoustic level. The first experiment deals with the spectral characteristics of the voice of patients who underwent thyroidectomy, with no laryngeal paralysis. The second study was conducted based on spectral characteristics of the voice of speakers with laryngeal post-thyroidectomy paralysis. Our final experiment was to study spatio-temporal characteristics of the voice of speakers who underwent thyroidectomy, with laryngeal paralysis. Articulatory interpretations, made from the acoustic data, reveal perturbations of gestures on both the glottal and supraglottal levels, with readjustment strategies varying according to patients. The concept of a "target" as a control space for execution of possible articulatory and acoustic entities, which are perceptually acceptable, seems particularly relevant in this study, since disordered speakers reorganize their productions according to their own physiological and anatomical constraints, caused by the disorder.
16

Eyes on the Road! : Off-Road Glance Durations when Performing Tasks on In-Vehicle Systems while Driving in a Simulator

Wahlberg, Linnea January 2013 (has links)
The 85th percentile off-road glances while performing three tasks on an in-vehicle system while driving in a simulator was investigated. The tasks were a radio task, a telephone task and a sound settings task which were performed at three occasions each. The distribution of 85th percentile off-road glance durations for each subject and task showed that durations differed between individuals rather than between tasks. It also turned out that durations longer than 2.00 seconds were not rare and 2 of 16 subjects had durations longer than 2.00 seconds in the radio task. Even though the distribution showed small differences between tasks on an individual level, differences on a group level were found between the tasks. A tendency of a learning effect was found, which implied a decrease in 85th percentile off-road glance durations as the tasks were performed at several occasions. A tendency of a floor effect in 85th percentile off-road glance durations, when the subjects are familiarized with tasks, was also found. Performance on a computerized trail-making test, measuring ability of visual search, motor speed and mental flexibility, was found not to be related with 85th percentile off-road glance durations.
17

L’impact de la variabilité articulatoire sur la perception auditive et l’acquisition de la production verbale chez des enfants présentant une dyslexie phonologique de CE1 / The impact of articulatory variability on auditory perception and the acquisition of verbal production in children with phonological dyslexia EC1

Derbal, Amel 23 January 2015 (has links)
Selon la littérature, la dyslexie est une difficulté d’apprentissage de la lecture, non liée à un retard mental, à un déficit sensoriel et ni à l’environnement social ou familial défavorisé. L’enfant dyslexique présente un écart de 18 mois à 24 mois par rapport aux réalisations scolaires d'un sujet en lecture, et ses potentialités intellectuelles mesurées par une échelle d'intelligence (Q.I.). Il souffre d’un dysfonctionnement des structures cérébrales entravant ses capacités cognitives avec une mauvaise identification des mots. Le diagnostic repose sur l’évaluation de l’habileté de la parole, de la lecture et de l’écriture. Dans ce travail, nous nous sommes intéressés aux enfants présentant une dyslexie phonologique. Cette dernière se caractérise principalement par une altération de la voie phonologique. Ces enfants présentent une sensibilité intracatégorielle supérieure à leur sensibilité intercatégorielle. Si nous acceptons l’hypothèse du couplage entre la perception et la production de la parole, nous pouvons parler d’une perturbation de l’exécution articulatoire de leurs productions qui explique leur retard de parole et leur trouble du langage. En effet, la parole obéit à certaines règles phonétiques et phonologiques ; la variation d’un phonème coarticulé est la source de la difficulté de sa discrimination chez l’enfant dyslexique, car un phonème présente plusieurs allophones. Nous avons supposé que cette variabilité articulatoire d’un seul phonème est la cause principale de leur retard de production et de perception de la parole. De ce fait, nous avons procédé à une analyse de leur production verbale à la recherche des marqueurs articulatoires qui diffèrent de ceux des enfants du groupe de contrôle. Quatre expériences ont été effectuées traitant des séquences de types (CV, CVCV, VCVCV et VCVCCV) en lecture de mots et de pseudo mots, à haute voix et à débit normal. Les paramètres temporels étudiés en ce qui concerne les indices acoustiques pour le segment consonantique ont été pour la consonne occlusive sourde, la durée du VTT, le silence acoustique et le VOT et, pour la consonne occlusive sonore, l’occlusion et le VOT. Nous avons aussi mesuré les segments vocaliques adjacents. Ces différentes analyses révèlent, lors de l’identification de mots, que la voie d’assemblage peut être partiellement opérationnelle chez les enfants dyslexiques, une déformation de mot partielle ou totale, des oppositions de sonorité ou de lieu d’articulation problématiques. A noter aussi des durées segmentales plus élevées chez l’enfant dyslexique que chez l’enfant normo-lecteur traduisant une lenteur dans la progression de la réalisation articulatoire nécessitant une durée supplémentaire. Ces paramètres ne suivent pas souvent une cohérence dans leurs proportions par rapport aux exigences imposées par les caractéristiques du lieu d’articulation et de la qualité du signal. Cependant nous constatons qu’ils peuvent préserver leur intelligibilité. Cette étude expérimentale a permis de mettre en évidence la notion de couplage entre la perception et le trouble articulatoire, voire le retard de la parole et du langage. / Available literature suggests that dyslexia is a learning disability that is neither linked to mental retardation, not to sensory disorder nor to deprived social background. The dyslexic child shows a difference of 18 to 24 months between the academic achievement of a reading subject and his or her intellectual potentials as measured by an intelligence scaling (IQ). The child suffers from brain structure dysfunction which impedes his cognitive abilities resulting in wrong word identification. We also know that the diagnosis is based on the evaluation of speech, reading and writing abilities. In our work, we focus on child phonological dyslexia. The latter is mainly characterized by impaired phonological route due to poor development of phonological ability. In reality, dyslexic children have a higher intra-categorical sensitivity rather than an inter-categorical perception. If we accept the idea of coupling between speech production and perception, we can posit the existence of a perturbation in the articulatory realisation of speech produced by dyslexic children which explains both their delayed speech and language disorder. Indeed, speech is governed by a number of phonetic and phonological rules; the variation of a coarticulated phoneme is at the root of difficulty of phoneme discrimination encountered by dyslexic children. This coarticulated phoneme has several allophones. We suggest that the articulatory variability of a single phoneme is the main cause of speech impairment. We performed an analysis of their verbal production in search of the articulatory markers that differ from children with no learning disability. With this in mind, we conducted four studies dealing with different sequences (CV, CVCV, and VCVCV VCVCCV). Tasks included reading words and pseudo-words, aloud and at normal speech rate. The measured parameters studied as regards acoustic cues for stops were VTT, the acoustic silent phase and VOT for voiceless stops; occlusion and VOT for the voiced stops, and duration for flanking vowels. During word identification, analyses reveal that the phonological route may be partially operational for our subjects. They also reveal partial or total word deformation; voicing contrast and place of articulation contrasts were also affected. Note should be taken of the higher measures found in dyslexic children than in normal readers, reflecting a slower gestures in their articulatory realizations due to additional time needed in these children. In addition, these parameters do not often follow a coherent pattern of proportional values relative to the requirements imposed by the characteristics of place of articulation and signal quality. However, we find that word intelligibility could be maintained. This experimental study has demonstrated the link between perception and articulation disorder, and to some extent speech and language production impairment.
18

Felt_space infrastructure : hyper vigilant spatiality to valence the visceral dimension

Emmett, Mathew Henry January 2013 (has links)
This thesis evolves perception as a hypothesis to reframe architectural praxis negotiated through agent-situation interaction. The research questions the geometric principles of architectural ordination to originate the ‘felt_space infrastructure’, a relational system of measurement concerned with the role of perception in mediating sensory space and the cognised environment. The methodological model for this research fuses perception and environmental stimuli, into a consistent generative process that penetrates the inner essence of space, to reveal the visceral parameter. These concepts are applied to develop a ‘coefficient of affordance’ typology, ‘hypervigilant’ tool set, and ‘cognitive_tope’ design methodology. Thus, by extending the architectural platform to consider perception as a design parameter, the thesis interprets the ‘inference schema’ as an instructional model to coordinate the acquisition of spatial reality through tensional and counter-tensional feedback dynamics. Three site-responsive case studies are used to advance the thesis. The first case study is descriptive and develops a typology of situated cognition to extend the ‘granularity’ of perceptual sensitisation (i.e. a fine-grained means of perceiving space). The second project is relational and questions how mapping can coordinate perceptual, cognitive and associative attention, as a ‘multi-webbed vector field’ comprised of attractors and deformations within a viewer-centred gravitational space. The third case study is causal, and demonstrates how a transactional-biased schema can generate, amplify and attenuate perceptual misalignment, thus triggering a visceral niche. The significance of the research is that it progresses generative perception as an additional variable for spatial practice, and promotes transactional methodologies to gain enhanced modes of spatial acuity to extend the repertoire of architectural practice.

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