Park and resource management agencies are looking for less costly ways to undertake park visitor surveys. The use of the Internet is often suggested as a way to reduce the costs of these surveys. By itself, however, the use of the Internet for park visitor surveys faces a number of methodological challenges that include the potential for coverage error, sampling difficulties and nonresponse error. A potential way of addressing these challenges is the use of a mixed-mode approach that combines the use of the Internet with another survey mode. The procedures for such a mixed-mode approach, however, have not been fully developed and evaluated. This study develops and evaluates a new mixed-mode approach –a face-to-face/web response – for a provincial park camper survey in British Columbia. The five key steps of this approach are: (a) selecting a random sample of occupied campsites; (b) undertaking a short interview with potential respondents; (c) obtaining an email address at the end of the interview; (d) distributing a postcard to potential respondents that contains the website and an individual access code; and (e) undertaking email follow-ups with nonrespondents. In evaluating this new approach, two experiments were conducted during the summer of 2010. The first experiment was conducted at Goldstream Provincial Park campground and was designed to compare a face-to-face/paper response to face-to-face/web response for several sources of survey errors and costs. The second experiment was conducted at 12 provincial park campgrounds throughout British Columbia and was designed to examine the potential for coverage error and the effect of a number of email follow-ups on return rates, nonresponse error and the substantive results. Taken together, these experiments indicate: a low potential for coverage error (i.e., 4% non-use Internet rate); a high email collection rate for follow-ups (i.e., 99% at Goldstream; a combined rate of 88% for 12 campgrounds); similar return rates between a paper mode (60%) and a web (59%) mode; the use of two email follow-ups reduced nonresponse error for a key variable (i.e., geographic location of residence), but not for all variables; low item nonresponse for both mixed-modes (about 1%); very few differences in the substantive results between each follow-up; a 9% cost saving for the web mode. This study suggests that a face-to face/web approach can provide a viable approach for undertaking park visitor surveys if there is high Internet coverage among park visitors. / Graduate / 0366 / 0344 / 0814 / brdyckfam@yahoo.com

The present dissertation develops a specific theory about everyday life called realist life mode theory. This theory is based on critical realism and consists of "work", "love" and "life mode" as central concepts. The background of the theory is the Danish life mode analysis developed by Thomas Højrup in the 1980:s. The aim of the study is to develop the central clusters of concepts in the realist life mode theory - i. e. "work", "love", "life mode" in a theoretical way. These concepts are seen as clusters since other related concepts are developed in connection to the concepts mentioned above. In connection to work I also discuss the concepts of "labour power", "labour receptor", and "work form"; in relation to love, "love power", "love receptor" and "love form" are discussed. And "life mode" is connected with the concept of "everyday life" in a more exact way than before. The argument of this study is that realist life mode theory is about two fundamental types of dominance - personal dominance and structural dominance. "Personal dominance" is used synonymously with "ownership". "Structural dominance" is dominance between non-personal, non-conscious entities. Life mode theory is a theory about ownership surrounded by structural dominances both beneath the owning person (sub-personally), and above (socially). Personal dominance - ownership - is produced via two human and societal processes - work and love. Work is defined as doing and occuring in the sphere of necessity. In work there especially are possibilities for ownership of the material surroundings. Love is defined as doing and occuring in the sphere of freedom. In love humans produce each other as self-owned persons through transaction of love power. Both work and love has great emancipatory potentials, and this theme is discussed in the present study. But, unfortunately, really existing work and love practices are to a great extent exploitative. Labour power is exploited in capitalism, and love power in patriarchy. When it comes to structural dominance, this study focuses on the following dominances: The dominance of labour receptor over labour power in men´s working life; the dominance of love power over love receptor in women´s love life. The dominance of work over love in men´s everyday life; the dominance of love over work in women´s everyday life. And on a more social level we find the following dominances: in the male life modes the work form dominates the love form. In female life modes the love form dominates the work form. And finally, in society as a whole male life modes have dominance over female life modes. When the dominance between social structures is analyzed, a distinction is made between "dominance form" and "the substance of dominance".

La majoria de les fallades en elements estructurals són degudes a càrrega per fatiga. En conseqüència, la fatiga mecànica és un factor clau per al disseny d'elements mecànics. En el cas de materials compòsits laminats, el procés de fallada per fatiga inclou diferents mecanismes de dany que resulten en la degradació del material. Un dels mecanismes de dany més importants és la delaminació entre capes del laminat. En el cas de components aeronàutics, les plaques de composit estan exposades a impactes i les delaminacions apareixen facilment en un laminat després d'un impacte. Molts components fets de compòsit tenen formes corbes, superposició de capes i capes amb diferents orientacions que fan que la delaminació es propagui en un mode mixt que depen de la grandària de la delaminació. És a dir, les delaminacions generalment es propaguen en mode mixt variable. És per això que és important desenvolupar nous mètodes per caracteritzar el creixement subcrític en mode mixt per fatiga de les delaminacions. El principal objectiu d'aquest treball és la caracterització del creixement en mode mixt variable de les delaminacions en compòsits laminats per efecte de càrregues a fatiga. Amb aquest fi, es proposa un nou model per al creixement per fatiga de la delaminació en mode mixt. Contràriament als models ja existents, el model que es proposa es formula d'acord a la variació no-monotònica dels paràmetres de propagació amb el mode mixt observada en diferents resultats experimentals. A més, es du a terme un anàlisi de l'assaig mixed-mode end load split (MMELS), la característica més important del qual és la variació del mode mixt a mesura que la delaminació creix. Per a aquest anàlisi, es tenen em compte dos mètodes teòrics presents en la literatura. No obstant, les expressions resultants per l'assaig MMELS no són equivalents i les diferències entre els dos mètodes poden ser importants, fins a 50 vegades. Per aquest motiu, en aquest treball es porta a terme un anàlisi alternatiu més acurat del MMELS per tal d'establir una comparació. Aquest anàlisi alternatiu es basa en el mètode dels elements finits i virtual crack closure technique (VCCT). D'aquest anàlisi en resulten importants aspectes a considerar per a la bona caracterització de materials utilitzant l'assaig MMELS. Durant l'estudi s'ha dissenyat i construït un utillatge per l'assaig MMELS. Per a la caracterització experimental de la propagació per fatiga de delaminacions en mode mixt variable s'utilitzen diferents provetes de laminats carboni/epoxy essencialment unidireccionals. També es du a terme un anàlisi fractogràfic d'algunes de les superfícies de fractura per delaminació. Els resultats experimentals són comparats amb les prediccions del model proposat per la propagació per fatiga d'esquerdes interlaminars. / Most of the failures in structural elements in use are a consequence of mechanical fatigue. Therefore, fatigue is a decisive factor in designing durable mechanical elements. In laminated composite materials, the fatigue process involves different damage mechanisms that result in the degradation of the material. One of the most important damage mechanisms is the delamination between plies of the laminate. In aeronautical applications, composite plates are sensitive to impact and delamination occurs readily in composite laminates on impact. Many composite components have curved shapes, tapered thickness and plies with different orientations, which make the delamination grow with a mode mix that depends on the extent of the crack. Thus, delaminations generally grow under varying mode mix. It is therefore important to develop methods that can characterise subcritical, mixed-mode growth in fatigue delamination. The main objective of the present investigation is the characterisation of the variable mixed-mode delamination in composite laminates under fatigue conditions. To this end, a mixed-mode fatigue delamination model is proposed. Oppositely to the mixed-mode fatigue delamination models present in the literature, the proposed model takes into account the non-monotonic variation of the propagation parameters with the mode mix observed in different experimental data. Moreover, the mixed-mode end load split (MMELS) test, which main characteristic is that the propagation mode of the interlaminar crack varies with the crack extent, is analysed. Two theoretical approaches present in the literature are considered. However, the resulting expressions for the MMELS test are not equivalent and the differences between approaches can be up to 50 times. A more accurate alternative analysis of the MMELS test is carried out in the present study for comparison. The alternative analysis is based on the finite element method and the virtual crack closure technique. Significant findings are found for precise materials characterisation using the MMELS test. A MMELS test rig is also designed and built. Different specimens of essentially unidirectional carbon/epoxy laminates are tested for the experimental characterisation of fatigue delamination under varying mode mix. A fractographic analysis is also conducted in some of the delaminated fracture surfaces. The experimental results are compared to the predictions of a proposed model for the fatigue propagation of interlaminar cracks.

Le désaccordage des roues aubagées est une thématique de recherche d’un intérêt tout particulier pour l’industrie aéronautique, en recherche constante d’outils de calcul toujours plus prédictifs et performants pour répondre aux exigences croissantes des organismes de certification. Si le phénomène est aujourd’hui relativement bien maîtrisé dans un cadre linéaire, la prise en compte des non-linéarités dans l’étude du désaccordage reste encore problématique, notamment en raison du manque de méthode adaptée pour mener ce type d’analyses sur des modèles industriels. L’objectif principal de ce travail de thèse est de proposer une nouvelle méthode de calcul permettant de déterminer efficacement la réponse forcée d’une roue aubagée désaccordée, en tenant compte de l’impact des non-linéarités sur la dynamique de la structure à l’échelle macroscopique. La méthode développée repose sur le concept de sous-structuration, et exploite la notion de mode complexe non-linéaire pour capturer les non-linéarités dans l’espace de réduction de chaque sous-structure. En adoptant une approche fréquentielle, les sous-structures sont représentées par des super-éléments non-linéaires, dont l’assemblage conduit au modèle réduit de la roue désaccordée. La résolution du système mathématique obtenu est ensuite réalisée numériquement par des techniques itératives. La méthode développée a pu être testée et validée sur différents systèmes soumis à des non-linéarités de frottement, allant du simple modèle phénoménologique à un modèle éléments finis de roue aubagée industrielle. Sur des modèles à paramètres concentrés de taille relativement faible, les performances très intéressantes de cette méthode permettent de conduire des études statistiques quantitatives sur l’impact du désaccordage en présence de non-linéarités. Les résultats obtenus suggèrent que le comportement du système non-linéaire face au désaccordage est susceptible d’être significativement différent du comportement de son homologue linéaire, d’où l’intérêt de mener ce type d’investigations. Les performances de cette méthode ont également pu être confirmées sur des modèles éléments finis de grande taille, en permettant de réaliser à un coût raisonnable des simulations de réponse forcée non-linéaire sur une roue industrielle désaccordée. / Mistuning of bladed disks has been a key topic of research for the aeronautics industry. To get accreditation for their engines, manufacturers must comply with evermore stringent requirements, and thus constantly seek for better simulation tools. Even though the phenomenon is well understood nowadays for linear systems, nonlinearities are still seldom taken into account when dealing with the mistuning of industrial structures, partly due to the lack of a dedicated method to tackle such a complex problematic. The main objective of this work is to develop a novel method allowing to compute efficiently the forced response of a mistuned bladed disk, while taking into account the impact of nonlinearities on the vibrations at a macroscopic scale. The method derived relies on a substructuring approach, and uses the concept of nonlinear complex modes to capture the nonlinearities in the reduction basis of each substructure. In the frequency domain, the substructures take the form of nonlinear superelements, which once assembled lead to the reduced-order model of the mistuned bladed disk. The resulting mathematical system is then solved by means of iterative solvers. This new method is tested and validated on different systems subjected to dry friction nonlinearities, from basic phenomenological models to large-scale finite element models of industrial structures. On lumped-parameter models, the performance of this method allows to investigate the statistical impact of mistuning in the presence of nonlinearities, by performing thousands of simulations. The results suggest that the behaviour of the nonlinear model can be significantly different from that of the linear one, hence the importance to carry out such investigations. The capabilities of the method have also been confirmed on large-scale models, by performing several forced response computations on a nonlinear and mistuned finite element model, at a reasonable cost

No description available.

This research (January 2009 to January 2012) described the impact of Work Based Learning (WBL) programmes on three large organisations involved in HE/employer engagement partnerships to up-skill experienced employees in NE England. A case study approach gathered rich qualitative data from public and private organisations, and their university partner which provided long-term, whole-day university-based master-class WBL programmes for University-accredited qualifications with the support of Higher Education Funding Council for England’s Strategic Development Funding. The public organisation delivered its own certificate-level sessions; and a Foundation Degree was delivered by the University and the organisation’s Directors. Modified action research observations of classes preceded a questionnaire profiling candidates, their motivations, and perspectives about WBL. Stakeholders’ semi-structured interviews (Wengraf, 2001) answered: “how, why and with what consequences does the Mode 2 learning of the individual impact the Mode 2 learning of the organisation”, premised on WBL using Mode 2 “how to” knowledge (Gibbons et al, 1994). Data, mainly collected from May to November 2010, was analysed using a modified grounded theory approach (Corbin and Strauss, 2008) with fractal concept analysis (Wasserman, Clair and Wilson, 2009). Rich descriptions of the impacts of WBL from the perspectives of those involved in HE/employer engagement partnerships resulted in models for developing new partnerships and incorporating employer engagement within a university. Original contributions to WBL knowledge included the Courtyard Model based upon findings including types of knowledge/concepts/values that emerged from the research which may potentially lead to new pedagogies. Impacts of WBL included networking that carried the organisation’s strategic vision into its culture to enhance its sustainability and possible growth. Candidates attributed valuing reputation, knowledge and people to universities as organisations. The Courtyard Model summarised the relationship between the impacts of WBL on the development of candidates and organisations in terms of reputation, knowledge, people, networks, culture and sustainability.

The foreign exchange market is one of the largest and most active financial markets with enormous daily trading volumes. Exchange rates are influenced by the interactions of a large number of agents, each operating with different intentions and on different time scales. This gives rise to nonlinear and non-stationary behaviour which complicates modelling. This research proposes a neural network based model trained on data filtered with a novel Empirical Mode Decomposition (EMD) filtering method for the forecasting of exchange rates. One minor and two major exchange rates are evaluated in this study. Firstly the ideal prediction horizons for trading are calculated for each of the exchange rates. The data is filtered according to this ideal prediction horizon using the EMD-filter. This EMD-filter dynamically filters the data based on the apparent number of intrinsic modes in the signal that can contribute towards prediction over the selected horizon. The filter is employed to filter out high frequency noise and components that would not contribute to the prediction of the exchange rate at the chosen timescale. This results in a clearer signal that still includes nonlinear behaviour. An artificial neural network predictor is trained on the filtered data using different sampling rates that are compatible with the cut-off frequency. The neural network is able to capture the nonlinear relationships between historic and future filtered data with greater certainty compared to a neural network trained on unfiltered data. Results show that the neural network trained on EMD-filtered data is significantly more accurate at prediction of exchange rates compared to the benchmark models of a neural network trained on unfiltered data and a random walk model for all the exchange rates. The EMD-filtered neural network’s predicted returns for the higher sample rates show higher correlations with the actual returns, and significant profits can be made when applying a trading strategy based on the predictions. Lower sample rates that just marginally satisfy the Nyquist criterion perform comparably with the neural network trained on unfiltered data; this may indicate that some aliasing occurs for these sampling rates as the EMD low-pass filter has a gradual cut-off, leaving some high frequency noise within the signal. The proposed model of the neural network trained on EMD-filtered data was able to uncover systematic relationships between the filtered inputs and actual outputs. The model is able to deliver profitable average monthly returns for most of the tested sampling rates and forecast horizons of the different exchange rates. This provides evidence that systematic predictable behaviour is present within exchange rates, and that this systematic behaviour can be modelled if it is properly separated from high frequency noise. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

The foreign exchange market is one of the largest and most active financial markets with enormous daily trading volumes. Exchange rates are influenced by the interactions of a large number of agents, each operating with different intentions and on different time scales. This gives rise to nonlinear and non-stationary behaviour which complicates modelling. This research proposes a neural network based model trained on data filtered with a novel Empirical Mode Decomposition (EMD) filtering method for the forecasting of exchange rates. One minor and two major exchange rates are evaluated in this study. Firstly the ideal prediction horizons for trading are calculated for each of the exchange rates. The data is filtered according to this ideal prediction horizon using the EMD-filter. This EMD-filter dynamically filters the data based on the apparent number of intrinsic modes in the signal that can contribute towards prediction over the selected horizon. The filter is employed to filter out high frequency noise and components that would not contribute to the prediction of the exchange rate at the chosen timescale. This results in a clearer signal that still includes nonlinear behaviour. An artificial neural network predictor is trained on the filtered data using different sampling rates that are compatible with the cut-off frequency. The neural network is able to capture the nonlinear relationships between historic and future filtered data with greater certainty compared to a neural network trained on unfiltered data. Results show that the neural network trained on EMD-filtered data is significantly more accurate at prediction of exchange rates compared to the benchmark models of a neural network trained on unfiltered data and a random walk model for all the exchange rates. The EMD-filtered neural network’s predicted returns for the higher sample rates show higher correlations with the actual returns, and significant profits can be made when applying a trading strategy based on the predictions. Lower sample rates that just marginally satisfy the Nyquist criterion perform comparably with the neural network trained on unfiltered data; this may indicate that some aliasing occurs for these sampling rates as the EMD low-pass filter has a gradual cut-off, leaving some high frequency noise within the signal. The proposed model of the neural network trained on EMD-filtered data was able to uncover systematic relationships between the filtered inputs and actual outputs. The model is able to deliver profitable average monthly returns for most of the tested sampling rates and forecast horizons of the different exchange rates. This provides evidence that systematic predictable behaviour is present within exchange rates, and that this systematic behaviour can be modelled if it is properly separated from high frequency noise. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

Published Article / In 2005 the third-year facilitators of the generic degree in nursing embarked on an action research initiative within a service learning pedagogy to revitalise the nursing process related to wound care.As a result of the action research a unique wound care project unfolded. This project embraced an integrated assessment approach in order to assess the competence related to wound care and to develop health care practitioners with generic- and field-specific competencies. Action research as mode of delivery for this project created an opportunity for producing Mode 2 knowledge where all participants contributed to the production of knowledge relevant to the wound care context.

Le projet de recherche financé par une subvention RDC du CRSNG et le CRIAQ est un partenariat entre Bombardier Aéronautique, Bell Helicopter, l'Université de Sherbrooke et l'Université Laval. Le principal objectif de ce projet est d'évaluer le potentiel de remplacer les actionneurs hydromécaniques par des actionneurs électromécaniques pour les commandes de vols primaires du Bell 407. La composante critique de l'actionneur électromécanique visé est un embrayage magnétorhéologique (MR). En effet, le fonctionnement de ce type d'embrayage est bien connu, mais la fiabilité ainsi que la durabilité de cette technologie restent à être prouvées. Le présent projet de maîtrise consiste donc à étudier la fiabilité ainsi que la durabilité d'un embrayage MR utilisé en glissement continu. Dans un premier temps, une analyse de fiabilité du système complet aux composantes (Top-Down) a été réalisée selon les méthodes et les techniques standards (FMEA et FTA) utilisées dans le domaine de l'aéronautique. Le manque d'informations concernant les modes de défaillance et la durabilité des embrayages MR a nécessité une étude expérimentale. Pour ce faire, un banc d'essais de longue durée complètement autonome a été conçu et fabriqué. Au total, 1750 heures de tests en glissement continu ont été réalisées sur des embrayages MR. Il y avait deux objectifs à ces tests. Le premier était d'étudier l'effet des paramètres d'opération (température, vitesse, couple) sur la durée de vie du fluide MR. Le deuxième était d'évaluer l'impact de la dégradation du fluide MR sur les performances d'un embrayage MR. Au final, le projet de recherche a permis de : 1. Évaluer les requis de fiabilité pour chacune des composantes d'un embrayage MR lorsqu'utilisé dans un système d'actuation pour des commandes de vol primaire d'un hélicoptère ; 2. Obtenir une compréhension plus fine du processus de dégradation du fluide MR et l'impact sur les performances des embrayages MR; 3. Doubler la durée de vie des embrayages MR par le développement d'une technique de circulation interne du fluide MR permettant l'utilisation d'un plus grand volume de fluide MR et ce, sans pénalité de poids, de volume et de coût.