Simultaneous in-situ measurements of waves, currents, water depth, suspended sediment concentrations and bed profiles were made in a rip channel on Perranporth Beach, Cornwall, UK. Perranporth is a high energy beach (annual offshore Hs = 1.6 m) which is macro-tidal (mean spring range = 6.3 m) and the grain size is medium sand (D50 = 0.28 – 0.34 mm). It can be classified as a low tide bar – rip beach and exhibits a relatively flat inter-tidal zone with pronounced rhythmic low tide bar - rip morphology. Data were collected over two field campaigns, totalling 14 tidal cycles and including 27 occurrences of rip currents, in a range of offshore wave heights (Hs = 0.5 – 3 m). The in-situ measurements were supplemented with morphological beach surveys. Sediment samples were taken for grain size analysis. The rip current was found to be tidally modulated. The strongest rip flow (0.7 m/s) occurred at mid to low tide, when waves were breaking on the adjacent bar. Rip flow persisted when the bar had dried out at the lowest tidal elevations. The rip was observed to pulse at a very low frequency (VLF) with a period of 15 - 20 minutes, which was shown to be influenced by wave breaking on the adjacent bar. The rip was completely in-active at high tide. Bedforms were ubiquitous in the rip channel and occurred at all stages of the tide. Visual observations found bedforms to be orientated shore parallel. When the rip was active, mean bedform length and height was 1.45 m and 0.06 m respectively. The size and position of the bedforms in the nearshore suggested that they were best classified as megaripples. When the rip was not active, the mean bedform length and height was 1.09 m and 0.06 m respectively. In rip conditions, with typical mean offshore flow rates of > 0.3 m/s, the bedforms migrated in an offshore direction at a mean rate of 0.16 cm/min and a maximum rate of 4.6 cm/min. The associated mean bedform sediment transport rate was 0.0020 kg/m/s, with a maximum rate of 0.054 kg/m/s. In the rip, migration rates were correlated with offshore directed mean flow strength. In non-rip conditions, bedform migration was onshore directed with a mean rate of 0.09 cm/min and a maximum rate of = 2.2 cm/min. The associated mean bedform transport rate was 0.0015 kg/m/s, with a maximum rate of = 0.041 kg/m/s. The onshore bedform transport was correlated with incident wave skewness, and was weakly correlated with orbital velocity. Over a tidal cycle, the offshore directed bedform transport was only marginally larger in rip currents than when it was when onshore directed in non-rip conditions. Sediment suspension in the rip current was shown to be dependent on the presence of waves. Suspended sediment transport was dominated by the mean flux. The mean flux contributed > 70% of total suspended transport on 19 out of the 27 observed rip current occurrences. The net contribution of the oscillatory flux was small compared to the mean flux. Within the oscillatory component, a frequency domain partitioning routine showed that the VLF motion was an important mechanism for driving offshore directed sediment transport. This was balanced by onshore directed sediment transport at incident wave frequency of a similar magnitude. Depth integration showed that the mean total suspended sediment transport was in the range of 0.03 kg/m/s to 0.08 kg/m/s. At high tide, when the rip was inactive suspended sediment transport rates were minimal compared to when the rip was active. Bedform transport was (on average) 6% of the total suspended sediment transport in a rip current. The new results presented here show that rip currents make an important contribution to offshore directed sediment transport. The magnitudes of transport indicate that future improvements to morphology change models should include rip driven offshore sediment transport.

The study of large-scale decentralised systems composed of numerous interacting agents that self-organise to perform a common task is receiving growing attention in several application domains. However, real world implementations are limited by a lack of well-established design methodologies that provide performance guarantees. Engineering such systems is a challenging task because of the difficulties to obtain the micro-macro link: a correspondence between the microscopic description of the individual agent behaviour and the macroscopic models that describe the system's dynamics at the global level. In this thesis, we propose an engineering methodology for designing decentralised systems, based on the concept of design patterns. A design pattern provides a general solution to a specific class of problems which are relevant in several application domains. The main component of the solution consists of a multi-level description of the collective process, from macro to micro models, accompanied by rules for converting the model parameters between description levels. In other words, the design pattern provides a formal description of the micro-macro link for a process that tackles a specific class of problems. Additionally, a design pattern provides a set of case studies to illustrate possible implementation alternatives both for simple or particularly challenging scenarios. We present a design pattern for the best-of-n, decentralised decision problem that is derived from a model of nest-site selection in honeybees. We present two case studies to showcase the design pattern usage in (i) a multiagent system interacting through a fully-connected network, and (ii) a swarm of particles moving on a bidimensional plane. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Program manipulation is the task to perform transformations on program code, and is normally done in order to optimize the code with respect of the utilization of some computer resource. Partial evaluation is the task when partial computations can be performed in a program before it is actually executed. If a parameter to a procedure is constant a specialized version of that procedure can be generated if the constant is inserted instead of the parameter in the procedure body and as much computations in the code as possible are performed. A system is described which works on programs written in INTERLISP, and which performs partial evaluation together with other transformations such as beta-expansion and certain other optimization operations. The system works on full LISP and not only for a "pure" LISP dialect, and deals with problems occurring there involving side-effects, variable assignments etc. An analysis of a previous system, REDFUN, results in a list of problems, desired extensions and new features. This is used as a basis for a new design, resulting in a new implementation, REDFUN-2. This implementation, design considerations, constraints in the system, remaining problems, and other experience from the development and experiments with the system are reported in this paper.

The purpose of this thesis was to explore how microstate human interactions produce macro level self-organization and emergence in a supply disruption scenario, as well as discover factors and typical human behaviour that bring about disruptions. This study argues that the complex adaptive system’s view of complexity is most suited scholarly foundation for this research enquiry. Drawing on the dissipative structure based explanation of emergence and self-organization in a complex adaptive system, this thesis further argues that an energy gradient between the ongoing and designed system conditions, known as adaptive tension, causes supply chains to self-organize and emerge. This study adopts a critical realist ontology operationalized by a qualitative case research and grounded theory based analysis. The data was collected using repertory grid interviews of 22 supply chain executives from 21 firms. In all 167 cases of supply disruptions were investigated. Findings illustrate that agent behaviours like loss of trust, over ambitious pursuit, use of power and privilege, conspiring against best practices and heedless performance were contributing to disruption. Impacted by these behaviours, supply chains demonstrated impaired disruption management capabilities and increased disruption probability. It was also discovered that some of these system patterns and microstate agent behaviours pushed the supply chains to a zone of emergent complexity where these networks self-organized and emerged into new structures or embraced changes in prevailing processes or goals. A conceptual model was developed to explain the transition from micro agent behaviour to system level self-organization and emergence. The model described alternate pathways of a supply chain under adaptive tension. The research makes three primary research contributions. Firstly, based upon the theoretical model, this research presents a conceptualization of supply chain emergence and self-organization from dissipative structures and adaptive tension based view of complexity. Secondly, it formally introduces and validates the role of behavioural and cognitive element of human actions in a supply chain scenario. Lastly, it affirms the complex adaptive system based conceptualization of supply chain networks. These contributions succeed in providing organizations with an explanation for observed deviations in their operations performance using a behavioural aspect of human agents.

One of the major challenges facing South African IT organisations today is the dramatic shortage of IT professionals. Both literature and business sentiment have indicated that employee turnover within the IT sector is on a continually rising trend. The ramifications of these high turnover rates translate into exorbitant direct and indirect costs to organisations. The purpose of this research was to identify the factors pertaining to the underlying structure of the turnover intention of these employees. A deeper understanding of these drivers may possibly enable management to reduce the turnover intention of employees within their organisations. A quantitative, multi-disciplinary research approach, focussing on the antecedents of turnover intention and the three systemic levels of organisational behaviour (micro, meso and macro) was used to operationalise the main research construct of this study. Data was collected by means of an anonymous self-administered web-based survey. A sample of 188 completed questionnaires was collected using a snowball sampling technique from the population of employees in the IT industry in South Africa. A statistical data reduction method, exploratory factor analysis, was conducted on the dataset to determine the underlying nature of the construct, IT employees’ perceived intention to resign from employment. After an appropriate number of factor analytic rounds, a robust 4-factor model of the data set was established. The results indicated that the factor, Personal Enrichment from Management Support, possibly plays the most significant role in understanding, monitoring, and managing IT employees’ perceived intention to resign from employment. The study provided support that monetary factors had the most significant influence in an employee’s decision to join an organisation; however, nonmonetary benefits, such as job satisfaction and skills development, were found to be more effective in retaining employees. The practical implications uncovered from this study will enable management to gain further insight into understanding the underlying factors and drivers of turnover intention and thereby minimise its impact on the organisation. / Dissertation (MBA)--University of Pretoria, 2013. / lmgibs2014 / Gordon Institute of Business Science (GIBS) / MBA / Unrestricted

This case study, through ten interviews with a variety of people working with or around theSwedish manga publishing industry, attempts to catalog the rise, decline and lasting effects of theindustrial boom of Japanese manga literature published in Sweden between the years 2000 and2017. The study explores relationship between subsidiary and mother company, as well as to fill inthe blanks of the research field as it pertains specifically to Sweden’s manga scene. The study usesthe theory of the culture industry by Adorno and Horkheimer (1944), together with Herbert Gans(1974) distinction between high and low culture to study this field. Theoretically the study alsooperates on the basis of the conditions that the globalized world awards these two aspects (Lechnerand Boli, 2008).The paper concludes that a mix between industry related issues, such as an over-saturation of themarket and failure to adapt to the global flow of cultural commerce is to blame for the decline. Thistogether with aspects of a cultural nature, such as an underlying disdain for manga as both only for,while at the same time harmful for children proved to be enough to almost entirely kill off mangapublishing in the country over the years studied.

Internet memes are exemplary forms of user-generated content in the age of social networking and user participation. This study draws attention to the work of an intersectional feminist community on Instagram who make use of this platform to discuss their personal politics via image macro memes. The community is made up of femmes who typically blend politics, pop culture, and a personal perspective into their content. This practice is identified as a contemporary feminist use of new media and is explored in relation to a theoretical reading of the current Third Wave of feminism as “embodied politics”. The theory of “disciplinary power” by Michel Foucault, and connections between disciplinary power with systems of oppression and social media are also employed to construct an understanding of feminist memes as a means of embodied resistance to disciplinary norms. This study seeks to explore how Internet memes are harnessed as a feminist mode of discourse, and why feminist meme creators (or “memers”) are motivated to use memes in this way. Therefore this research locates an intersection between digital culture and feminist use of new media. The research explores the possibility that Internet memes can serve as a creative and effective mode of feminist discourse in resistance to various forms of marginalisation - which occur both online and offline.

There is a strong uptake of femtocell deployment as small cell application platforms in the upcoming LTE networks. In such two-tier networks of LTE-femtocell base stations, a large portion of the assigned spectrum is used sporadically leading to underutilisation of valuable frequency resources. Novel spectrum access techniques are necessary to solve these current spectrum inefficiency problems. Therefore, spectrum management solutions should have the features to improve spectrum access in both temporal and spatial manner. Cognitive Radio (CR) with the Dynamic Spectrum Access (DSA) is considered to be the key technology in this research in order to increase the spectrum efficiency. This is an effective solution to allow a group of Secondary Users (SUs) to share the radio spectrum initially allocated to the Primary User (PUs) at no interference. The core aim of this thesis is to develop new cognitive LTE-femtocell systems that offer a 4G vision, to facilitate the radio network management in order to increase the network capacity and further improve spectrum access probabilities. In this thesis, a new spectrum management model for cognitive radio networks is considered to enable a seamless integration of multi-access technology with existing networks. This involves the design of efficient resource allocation algorithms that are able to respond to the rapid changes in the dynamic wireless environment and primary users activities. Throughout this thesis a variety of network upgraded functions are developed using application simulation scenarios. Therefore, the proposed algorithms, mechanisms, methods, and system models are not restricted in the considered networks, but rather have a wider applicability to be used in other technologies. This thesis mainly investigates three aspects of research issues relating to the efficient management of cognitive networks: First, novel spectrum resource management modules are proposed to maximise the spectrum access by rapidly detecting the available transmission opportunities. Secondly, a developed pilot power controlling algorithm is introduced to minimise the power consumption by considering mobile position and application requirements. Also, there is investigation on the impact of deploying different numbers of femtocell base stations in LTE domain to identify the optimum cell size for future networks. Finally, a novel call admission control mechanism for mobility management is proposed to support seamless handover between LTE and femtocell domains. This is performed by assigning high speed mobile users to the LTE system to avoid unnecessary handovers. The proposed solutions were examined by simulation and numerical analysis to show the strength of cognitive femtocell deployment for the required applications. The results show that the new system design based on cognitive radio configuration enable an efficient resource management in terms of spectrum allocation, adaptive pilot power control, and mobile handover. The proposed framework and algorithms offer a novel spectrum management for self organised LTE-femtocell architecture. Eventually, this research shows that certain architectures fulfilling spectrum management requirements are implementable in practice and display good performance in dynamic wireless environments which recommends the consideration of CR systems in LTE and femtocell networks.

Dans un contexte où la pollution, qu'elle soit sonore ou environnementale, continue de s'accroître malgré les efforts déployés, ce projet de recherche propose la conception d'un absorbant acoustique à base de fibres naturelles possédant un fort potentiel acoustique, la soie d'asclépiade. Produite au Québec, cette fibre permet de respecter les grands principes du développement durable. Pour assurer une conception optimale, la démarche proposée passe par l'adaptation d'un modèle acoustique micro-macro de matériaux fibreux afin de relier le comportement acoustique aux paramètres de conception, qui sont l'orientation des fibres, leurs diamètres ainsi que la masse volumique apparente de l'agrégat. En premier lieu, la validité du modèle micro-macro pour le cas des fibres creuses est investiguée. Pour ce faire, une correction de l'expression de la porosité du matériau est proposée afin d'alimenter le modèle micro-macro avec la porosité externe aux fibres uniquement, comme cela aurait été le cas pour des fibres pleines. Cette approche est validée à l'aide de mesures directes et ultrasonores de la porosité, montrant que la porosité « acoustique » est inférieure à la porosité totale mesurée directement. Les résultats du modèle sont ensuite comparés avec des mesures en tube d'impédance d'échantillons de fibres en vrac à différents taux de compaction. On peut observer que le comportement global de la fibre est bien capté par le modèle, qui se compare bien avec le modèle classique de Miki. On y observe aussi que la résistivité mesurée suit bien les prédictions du modèle pour un arrangement de fibres dans le plan perpendiculaire au sens de propagation de l'onde acoustique. C'est aussi cet arrangement qui permet d'obtenir les meilleurs résultats en termes d'absorption acoustique. Ensuite, une modélisation de type double porosité avec une loi des mélanges est proposée afin de capter l'effet acoustique de la fibre creuse. On peut observer que pour ces dimensions de fibres, l'effet n'est pas très marqué car la perméabilité du domaine microporeux est faible. Par contre, la loi des mélanges permet de bien corriger le modèle proposé. En second lieu, des tests de fabrication sont réalisés à partir de mats d'asclépiade. Le mat est un mélange d'asclépiade et de fibres bicomposantes formé d'un empilement thermolié de voiles préalablement cardés. Les mats sont compactés et thermoliés de façon à obtenir un matériau d'épaisseur et de masse volumique apparente déterminées. Les meilleurs résultats ont été obtenus sous presse chauffante. Le matériau résultant est ensuite testé et comparé à la mousse de mélamine, une référence en termes d'absorbant acoustique léger. La démarche suivie dans ces travaux a permis de fabriquer un matériau acoustique exploitant le plein potentiel acoustique de la soie d'asclépiade grâce à une optimisation via le modèle prédictif proposé. Pour des développements futurs, il serait intéressant d'étudier les effets de fibres creuses de plus grandes dimensions, en plus de valider l'applicabilité du procédé de fabrication sur ces fibres.

El objetivo general de la tesis fue determinar cómo influye la implementación de un sistema computarizado de información en la mejora de los macro indicadores de gestión en el control de medicamentos. El enfoque de la investigación es cuantitativo y de alcance explicativo-experimental. Los métodos empleados fueron el científico, inductivo-deductivo, analítico-sintético y experimental. La investigación es de tipo aplicado con un diseño cuasiexperimental con series cronológicas. Se utilizó una guía de revisión documental aplicada a una muestra de siete (7) periodos, donde se midieron los macro indicadores de gestión logística. / Tesis