published_or_final_version / Economics and Finance / Master / Master of Economics

In spoken French, the phonological processes of liaison and resyllabification can render word and syllable boundaries ambiguous. In the case of liaison, for example, the /n/ in the masculine indefinite article un [oẽ] is normally latent, but when followed by a vowel-initial word the /n/ surfaces and is resyllabified as the onset of that word. Thus, the phrases un air ‘a melody’ and un nerf ‘a nerve’ are produced with identical phonemic content and syllable boundaries [oẽ.nɛʁ]). Some research has suggested that speakers of French give listeners cues to word boundaries by varying the duration of consonants that surface in liaison environments relative to consonants produced word-initially. Production studies (e.g. Wauquier-Gravelines 1996; Spinelli et al. 2003) have demonstrated that liaison consonants (e.g. /n/ in un air) are significantly shorter than the same consonant in initial position (e.g. /n/ in un nerf). Studies on the perception of spoken French have suggested that listeners exploit these durational differences in the segmentation of running speech (e.g. Gaskell et al. 2002; Spinelli et al. 2003), though no study to date has tested this hypothesis directly. The current study employs a direct test of the exploitation of duration as a segmentation cue by manipulating this single acoustic factor while holding all other factors constant. Thirty-six native speakers of French and 54 adult learners of French as a second language (L2) were tested on both an AX discrimination task and a forced-choice identification task which employed stimuli in which the durations of pivotal consonants (e.g. /n/ in [oẽ.nɛʁ]) were instrumentally shortened and lengthened. The results suggest that duration alone can indeed modulate the lexical interpretation of sequences rendered sequences in spoken French. Shortened stimuli elicited a significantly larger proportion of vowel-initial (liaison) responses, while lengthened stimuli elicited a significantly larger proportion of consonant-initial responses, indicating that both native and (advanced) non-native speakers are indeed sensitive to this acoustic cue. These results add to a growing body of work demonstrating that listeners use extremely fined-grained acoustic detail to modulate lexical access (e.g. Salverda et al. 2003; Shatzman & McQueen 2006). In addition, the current results have manifest ramifications for study of the upper limits of L2 acquisition and the plasticity of the adult perceptual system in that they show evidence nativelike sensitivity to non-contrastive phonological variation. / text

A project was sponsored by the SERC for research into the design of a colour vision system for the detection of print faults in rotary screen printed fabrics. The research was carried out at De Montfort University (formerly named Leicester Polytechnic), which has previous experience with Image Processing in relation to Textiles. The proposed system was required to identify, process and correct the common print faults which can occur during rotary screen printing. These can be divided into two main categories, systematic and random faults. This thesis covers the work undertakeni n the developmento f a laboratory-basedin spection systema ndt he subsequendte velopmenat nd testingo f methodologiesto facilitate factory-based on-line inspection. Initial investigation identified the requirement for colour segmentation algorithmsa ndt he researchin to anda nalysiso f suitablem ethodologiesf or segmentationf orms a fundamental part of this thesis. Important, new colour segmentation algorithms were developed from first principles by the author. These new methods offer improvements (in most cases significant) over the current `state-of-the-art' colour segmentation technology, and are applicable to a wide-range of computer vision tasks. These proposed methodologies have been rigorously tested and the findings of the investigation are presented as part of this thesis.

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The number of people aged 60 years and above is increasing in the UK. In total, this age group represents 22% of the population with estimates indicating a rise to 29% by 2050 (United Nations, 2009). One market sector that is extremely important to the health and wellbeing of older people is grocery retail (Khan, 1981). However, little previous research has addressed how older people rate the service delivered by their grocery provider, particularly in regard to satisfaction. To reconcile this gap in theoretical understanding, a sequential transformative mixed-method research design was specified using 36 qualitative interviews and quantitative questionnaires with 524 subjects. A model including both drivers and consequences of satisfaction was formulated using past research. As such, an antecedent scale for grocery store image was developed via procedures suggested in the extant literature (e.g. DeVellis, 2003). Pre-existing scales (i.e. commitment and loyalty) representing exemplary reliability and validity were borrowed and specified as consequences. The scales were modified and integrated into a ‘structural equation model’. Older people were found to place a high level of importance in aspects of merchandise, store environment, personnel and services. Price/promotions and clientele were found to be insignificant in driving satisfaction. Differences in factor mean scores and structural parameters were then analysed using ‘finite mixture structural equation modelling’ to identify segments of similar respondents (Jedidi et al, 1997). Using posterior probabilities, the emerging segments were subjected to profiling using personal and behavioural variables (Hahn et al, 2002). Market Segmentation showed three groups of similar respondents in the sample population, differing in factor mean scores and psychological operationalisation of satisfaction. Nonetheless, only several differences in personal and behavioural characteristics were found between the segments. Whilst, the results show that segmenting this group is necessary when measuring satisfaction, basing this purely on a priori descriptive variables might be erroneous given the inherent levels of unobserved heterogeneity. The model developed and tested in this study is considered the most up-to-date available in the literature.

Astrocytes, the most abundant glial cell type in the brain, undergo a number of roles in brain physiology; among them, the energetic support of neurons is the best characterized. Contained within astrocytes is the brain’s obligate energy store, glycogen. Through glycogenolysis, glycogen, a storage form of glucose, is converted to pyruvate that is further reduced to lactate and transferred to neurons as an energy source via MCTs. Glycogen is a multi-branched polysaccharide synthesized from the glucose uptaken in astrocytes. It has been shown that glycogen accumulates with age and contributes to the physiological ageing process in the brain. In this study, we compared glycogen distribution between young adults and geriatric mice to understand the energy consumption of synaptic terminals during ageing using computational tools. We segmented and densely reconstructed neuropil and glycogen granules within six (three 4 month old old and three 24 month old) volumes of Layer 1 somatosensory cortex mice brains from FIB-SEM stacks, using a combination of semi-automated and manual tools, ilastik and TrakEM2. Finally, the 3D visualization software, Blender, was used to analyze the dataset using the DBSCAN and KDTree Nearest neighbor algorithms to study the distribution of glycogen granules compared to synapses, using a plugin that was developed for this purpose. The Nearest Neighbors and clustering results of 6 datasets show that glycogen clusters around excitatory synapses more than inhibitory synapses and that, in general, glycogen is found around axonal boutons more than dendritic spines. There was no significant accumulation of glycogen with ageing within our admittedly small dataset. However, there was a homogenization of glycogen distribution with age and that is consistent with published literature. We conclude that glycogen distribution in the brain is not a random process but follows a function distribution.

This thesis presents a general framework and method for detection of an object in a video based on apparent motion. The object moves, at some unknown time, differently than the “background” motion, which can be induced from camera motion. The goal of proposed method is to detect and segment the object as soon it moves in an online manner. Since motion estimation can be unreliable between frames, more than two frames are needed to reliably detect the object. Observing more frames before declaring a detection may lead to a more accurate detection and segmentation, since more motion may be observed leading to a stronger motion cue. However, this leads to greater delay. The proposed method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms, defined as declarations of detection before the object moves or incorrect or inaccurate segmentation at the detection time. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.