Applications of the behavioural homogeneity evaluation framework: the predictive ability of consumer involvement for international food market segmentation

This article proposes a framework of alternative international marketing strategies, based on the evaluation of intra- and inter-cultural behavioural homogeneity for market segmentation. The framework developed in this study provides a generic structure to behavioural homogeneity, proposing consumer involvement as a construct with unique predictive ability for international marketing strategy decisions. A model-based segmentation process, using structural equation models, is implemented to illustrate the application of the framework.

Applications of ultralong Raman fibre lasers in photonics

This thesis presents a numerical and experimental investigation on applications of ultralong Raman fibre lasers in optical communications, supercontinuum generation and soliton transmission. The research work is divided in four main sections. The first involves the numerical investigation of URFL intra-cavity power and the relative intensity noise transfer evolution along the transmission span. The performance of the URFL is compared with amplification systems of similar complexity. In the case of intracavity power evolution, URFL is compared with a first order Raman amplification system. For the RIN transfer investigation, URFL is compared with a bi-directional dual wavelength pumping system. The RIN transfer function is investigated for several cavity design parameters such as span length, pump distribution and FBG reflectivity. The following section deals with experimental results of URFL cavities. The enhancement of the available spectral bandwidth in the C-band and its spectral flatness are investigated for single and multi-FBGs cavity system. Further work regarding extended URFL cavity in combination with Rayleigh scattering as random distributed feedback produced a laser cavity with dual wavelength outputs independent to each other. The last two sections relate to URFL application in supercontinuum (SC) generation and soliton transmission. URFL becomes an enhancement structure for SC generation. This thesis shows successful experimental results of SC generation using conventional single mode optical fibre and pumped with a continuous wave source. The last section is dedicated to soliton transmission and the study of soliton propagation dynamics. The experimental results of exact soliton transmission over multiple soliton periods using conventional single mode fibre are shown in this thesis. The effect of the input signal, pump distribution, span length and FBGs reflectivity on the soliton propagation dynamics is investigated experimentally and numerically.

Applications of fractals to image data compression

Digital image processing is exploited in many diverse applications but the size of digital images places excessive demands on current storage and transmission technology. Image data compression is required to permit further use of digital image processing. Conventional image compression techniques based on statistical analysis have reached a saturation level so it is necessary to explore more radical methods. This thesis is concerned with novel methods, based on the use of fractals, for achieving significant compression of image data within reasonable processing time without introducing excessive distortion. Images are modelled as fractal data and this model is exploited directly by compression schemes. The validity of this is demonstrated by showing that the fractal complexity measure of fractal dimension is an excellent predictor of image compressibility. A method of fractal waveform coding is developed which has low computational demands and performs better than conventional waveform coding methods such as PCM and DPCM. Fractal techniques based on the use of space-filling curves are developed as a mechanism for hierarchical application of conventional techniques. Two particular applications are highlighted: the re-ordering of data during image scanning and the mapping of multi-dimensional data to one dimension. It is shown that there are many possible space-filling curves which may be used to scan images and that selection of an optimum curve leads to significantly improved data compression. The multi-dimensional mapping property of space-filling curves is used to speed up substantially the lookup process in vector quantisation. Iterated function systems are compared with vector quantisers and the computational complexity or iterated function system encoding is also reduced by using the efficient matching algcnithms identified for vector quantisers.

Fabrication and applications of fibre Bragg gratings

The consequences of fabricating Bragg gratings in various fibres, with or without hydrogen loading, and with varying laser power levels are explored. Three new techniques for fabricating chirped gratings are presented. Beams with dissimilar wavefront curvatures are interfered to give chirped gratings. With the same aim techniques of writing gratings on tapered fibres and on deformed fibres are also covered. With these techniques, a wide variety of gratings has been fabricated from the 'superbroad' (with bandwidths of up to 180 nm), small to medium bandwidth gratings with linear chirp profiles and quadratic chirped gratings. It is demonstrated that chirped grating can be concatenated to form all-fibre Fabry-Perot and Moiré resonators. These are further concatenated with chirped gratings to produce filters with narrow passbands and very broad stopbands. A number of other applications are also addressed. The use of chirped fibre gratings for dispersion compensation and femtosecond chirped pulse amplification is demonstrated. Chirped gratings are used as dispersive elements in modelocked fibre lasers producing ultrashort pulses. A chirped fibre grating Fabry-Perot transmission filter is used in a continuous wave laser that exhibits eleven simultaneously lasing wavelengths. Finally, the use of grating-coupler devices as variable reflectivity mirrors for laser optimisation and gain clamping is considered.

Accuracy and applications of group MEG studies using cortical source locations estimated from participants' scalp surfaces

We contend that powerful group studies can be conducted using magnetoencephalography (MEG), which can provide useful insights into the approximate distribution of the neural activity detected with MEG without requiring magnetic resonance imaging (MRI) for each participant. Instead, a participant's MRI is approximated with one chosen as a best match on the basis of the scalp surface from a database of available MRIs. Because large inter-individual variability in sulcal and gyral patterns is an inherent source of blurring in studies using grouped functional activity, the additional error introduced by this approximation procedure has little effect on the group results, and offers a sufficiently close approximation to that of the participants to yield a good indication of the true distribution of the grouped neural activity. T1-weighted MRIs of 28 adults were acquired in a variety of MR systems. An artificial functional image was prepared for each person in which eight 5 × 5 × 5 mm regions of brain activation were simulated. Spatial normalisation was applied to each image using transformations calculated using SPM99 with (1) the participant's actual MRI, and (2) the best matched MRI substituted from those of the other 27 participants. The distribution of distances between the locations of points using real and substituted MRIs had a modal value of 6 mm with 90% of cases falling below 12.5 mm. The effects of this -approach on real grouped SAM source imaging of MEG data in a verbal fluency task are also shown. The distribution of MEG activity in the estimated average response is very similar to that produced when using the real MRIs. © 2003 Wiley-Liss, Inc.

The biotechnological applications of transglutaminases

Transglutaminases catalyse a diverse range of reactions leading to the modification of proteins and peptides such that their physical, chemical and biological properties become changed. They are found in many different living organisms and as a consequence display subtle differences in their biochemical and physical properties. it is therefore not surprising that this group of enzymes have been exploited as applied biocatalysts in a wide range of commercial sectors varying from the textile industry to the highly lucrative cosmetic industry. in addition the pathophysiological importance of this group of enzymes has increased significantly over the last decade with their involvement noted in a number of human diseases. As a consequence their identification as therapeutic targets or as monitoring aids for a range of different diseases has caused significant interest from the diagnostics and pharmaceutical industries. This review describes some of the current applications of transglutaminases; together with their potential strategic importance and future uses.

Optical communications applications of ultra-long Raman fiber lasers

Recent work on ultra-long Raman fiber lasers has shown that it is possible to create quasi-lossless transmission conditions in fiber spans long enough to be considered for high speed optical communications. This paper reviews how quasi-lossless transmission conditions are reached and presents experimental results of 40Gb/s transmission in a quasi lossless system. The performance is compared with a conventional EDFA based system.

The development and applications of the combined use of NMR and ultrasound

The objective of the research carried out in this report was to observe the first ever in-situ sonochemical reaction in the NMR Spectrometer in the megahertz region of ultrasound. Several reactions were investigated as potential systems for a sonochemical reaction followed by NMR spectroscopy. The primary problem to resolve when applying ultrasound to a chemical reaction is that of heating. Ultrasound causes the liquid to move and produces 'hot spots' resulting in an increase in sample temperature. The problem was confronted by producing a device that would counteract this effect and so remove the need to account for heating. However, the design of the device limited the length of time during which it would function. Longer reaction times were required to enable observations to be carried out in the NMR spectrometer. The fIrst and most obvious reactions attempted were those of the well-known ultrasonic dosimeter. Such a reaction would, theoretically, enable the author to simultaneously observe a reaction and determine the exact power entering the system for direct comparison of results. Unfortunately, in order to monitor the reactions in the NMR spectrometer the reactant concentrations had to be signifIcantly increased, which resulted in a notable increase in reaction time, making the experiment too lengthy to follow in the time allocated. The Diels-Alder Reaction is probably one of the most highly investigated reaction systems in the field of chemistry and it was this to which the author turned her attention. Previous authors have carried out ultrasonic investigations, with considerable success, for the reaction of anthracene with maleic anhydride. It was this reaction in particular that was next attempted. The first ever sonochemically enhanced reaction using a frequency of ultrasound in the megahertz (MHz) region was successfully carried out as bench experiments. Due to the complexity of the component reactants the product would precipitate from the solution and because the reaction could only be monitored by its formation, it was not possible to observe the reaction in the NMR spectrometer. The solvolysis of 2-chloro-2-methylpropane was examined in various solvent systems; the most suitable of which was determined to be aqueous 2-methylpropan-2-ol. The experiment was successfully enhanced by the application of ultrasound and monitored in-situ in the NMR spectrometer. The increase in product formation of an ultrasonic reaction over that of a traditional thermal reaction occurred. A range of 1.4 to 2.9 fold improvement was noted, dependent upon the reaction conditions investigated. An investigation into the effect of sonication upon a large biological molecule, in this case aqueous lysozyme, was carried out. An easily observed effect upon the sample was noted but no explanation for the observed effects could be established.

Applications of differential geometry to high spin field theories

The main aim of this thesis is to investigate the application of methods of differential geometry to the constraint analysis of relativistic high spin field theories. As a starting point the coordinate dependent descriptions of the Lagrangian and Dirac-Bergmann constraint algorithms are reviewed for general second order systems. These two algorithms are then respectively employed to analyse the constraint structure of the massive spin-1 Proca field from the Lagrangian and Hamiltonian viewpoints. As an example of a coupled field theoretic system the constraint analysis of the massive Rarita-Schwinger spin-3/2 field coupled to an external electromagnetic field is then reviewed in terms of the coordinate dependent Dirac-Bergmann algorithm for first order systems. The standard Velo-Zwanziger and Johnson-Sudarshan inconsistencies that this coupled system seemingly suffers from are then discussed in light of this full constraint analysis and it is found that both these pathologies degenerate to a field-induced loss of degrees of freedom. A description of the geometrical version of the Dirac-Bergmann algorithm developed by Gotay, Nester and Hinds begins the geometrical examination of high spin field theories. This geometric constraint algorithm is then applied to the free Proca field and to two Proca field couplings; the first of which is the minimal coupling to an external electromagnetic field whilst the second is the coupling to an external symmetric tensor field. The onset of acausality in this latter coupled case is then considered in relation to the geometric constraint algorithm.