5 resultados para top-down approach

em Glasgow Theses Service


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One of the main unresolved questions in science is how non-living matter became alive in a process known as abiognesis, which aims to explain how from a primordial soup scenario containing simple molecules, by following a ``bottom up'' approach, complex biomolecules emerged forming the first living system, known as a protocell. A protocell is defined by the interplay of three sub-systems which are considered requirements for life: information molecules, metabolism, and compartmentalization. This thesis investigates the role of compartmentalization during the emergence of life, and how simple membrane aggregates could evolve into entities that were able to develop ``life-like'' behaviours, and in particular how such evolution could happen without the presence of information molecules. Our ultimate objective is to create an autonomous evolvable system, and in order tp do so we will try to engineer life following a ``top-down'' approach, where an initial platform capable of evolving chemistry will be constructed, but the chemistry being dependent on the robotic adjunct, and how then this platform can be de-constructed in iterative operations until it is fully disconnected from the evolvable system, the system then being inherently autonomous. The first project of this thesis describes how the initial platform was designed and built. The platform was based on the model of a standard liquid handling robot, with the main difference with respect to other similar robots being that we used a 3D-printer in order to prototype the robot and build its main equipment, like a liquid dispensing system, tool movement mechanism, and washing procedures. The robot was able to mix different components and create populations of droplets in a Petri dish filled with aqueous phase. The Petri dish was then observed by a camera, which analysed the behaviours described by the droplets and fed this information back to the robot. Using this loop, the robot was then able to implement an evolutionary algorithm, where populations of droplets were evolved towards defined life-like behaviours. The second project of this thesis aimed to remove as many mechanical parts as possible from the robot while keeping the evolvable chemistry intact. In order to do so, we encapsulated the functionalities of the previous liquid handling robot into a single monolithic 3D-printed device. This device was able to mix different components, generate populations of droplets in an aqueous phase, and was also equipped with a camera in order to analyse the experiments. Moreover, because the full fabrication process of the devices happened in a 3D-printer, we were also able to alter its experimental arena by adding different obstacles where to evolve the droplets, enabling us to study how environmental changes can shape evolution. By doing so, we were able to embody evolutionary characteristics into our device, removing constraints from the physical platform, and taking one step forward to a possible autonomous evolvable system.

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This thesis examines deindustrialisation, the declining contribution of industrial activities to economic output and employment, in Lanarkshire, Scotland’s largest coalfield between the early nineteenth and mid-twentieth century. It focuses on contraction between the National Coal Board’s (NCB) vesting in 1947 and the closure of Lanarkshire’s last colliery, Cardowan, in 1983. Deindustrialisation was not the natural outcome of either market forces or geological exhaustion. Colliery closures and falling coal employment were the result of policy-makers’ decisions. The thesis consists of four thematic chapters: political economy, moral economy, class and community, and generation and gender. The analysis is based on archival sources including Scottish Office reports and correspondence relating to regional policy, and NCB records. These are supported by National Union of Mineworkers Scottish Area and STUC meeting minutes, and oral history testimonies from over 30 men and women with Lanarkshire coalfield backgrounds, as well as two focus groups. The first two chapters analyse the process of deindustrialisation, with the first offering a top-down perspective and the second a bottom-up viewpoint. In chapter one deindustrialisation is analysed through changes in political economy. Shifts in labour market structure are examined through the development of regional policy and its administration by the Scottish Office. The analysis centres upon a policy network of Scottish business elites and civil servants who shaped a vision of modernisation via industrial diversification through attracting inward investment. In chapter two the perspective shifts to community and workforce. It analyses responses to coalfield contraction through a moral economy of customary rights to colliery employment. A detailed investigation of Lanarkshire colliery closures between the 1940s and 1980s emphasises the protracted nature of deindustrialisation. Chapters three and four consider the social and cultural structures which shaped the moral economy but were heavily altered by deindustrialisation. Chapter three focuses on the dense networks that linked occupation, community, and class consciousness. Increasing coalfield centralisation and remote control of pits from NCB headquarters in London, and mounting hostility to coal closures, contributed to an accentuated sense of Scottish-ness. Chapter four illuminates gender and generational dimensions. The differing experiences of cohorts of men who faced either early retirement, redundancy or transfer to alternative sectors, or those who never attained anticipated industrial employment due to final closures, are analysed in terms of constructions of masculinity and the endurance of cultural as well as material losses. This is counterpoised to women who gained industrial work in assembly plants and the perceived gradual attainment of an improved economic and social position whilst continuing to navigate structures of patriarchy.

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This study focuses on the learning and teaching of Reading in English as a Foreign Language (REFL), in Libya. The study draws on an action research process in which I sought to look critically at students and teachers of English as a Foreign Language (EFL) in Libya as they learned and taught REFL in four Libyan research sites. The Libyan EFL educational system is influenced by two main factors: the method of teaching the Holy-Quran and the long-time ban on teaching EFL by the former Libyan regime under Muammar Gaddafi. Both of these factors have affected the learning and teaching of REFL and I outline these contextual factors in the first chapter of the thesis. This investigation, and the exploration of the challenges that Libyan university students encounter in their REFL, is supported by attention to reading models. These models helped to provide an analytical framework and starting point for understanding the many processes involved in reading for meaning and in reading to satisfy teacher instructions. The theoretical framework I adopted was based, mainly and initially, on top-down, bottom-up, interactive and compensatory interactive models. I drew on these models with a view to understanding whether and how the processes of reading described in the models could be applied to the reading of EFL students and whether these models could help me to better understand what was going on in REFL. The diagnosis stage of the study provided initial data collected from four Libyan research sites with research tools including video-recorded classroom observations, semi-structured interviews with teachers before and after lesson observation, and think-aloud protocols (TAPs) with 24 students (six from each university) in which I examined their REFL reading behaviours and strategies. This stage indicated that the majority of students shared behaviours such as reading aloud, reading each word in the text, articulating the phonemes and syllables of words, or skipping words if they could not pronounce them. Overall this first stage indicated that alternative methods of teaching REFL were needed in order to encourage ‘reading for meaning’ that might be based on strategies related to eventual interactive reading models adapted for REFL. The second phase of this research project was an Intervention Phase involving two team-teaching sessions in one of the four stage one universities. In each session, I worked with the teacher of one group to introduce an alternative method of REFL. This method was based on teaching different reading strategies to encourage the students to work towards an eventual interactive way of reading for meaning. A focus group discussion and TAPs followed the lessons with six students in order to discuss the 'new' method. Next were two video-recorded classroom observations which were followed by an audio-recorded discussion with the teacher about these methods. Finally, I conducted a Skype interview with the class teacher at the end of the semester to discuss any changes he had made in his teaching or had observed in his students' reading with respect to reading behaviour strategies, and reactions and performance of the students as he continued to use the 'new' method. The results of the intervention stage indicate that the teacher, perhaps not surprisingly, can play an important role in adding to students’ knowledge and confidence and in improving their REFL strategies. For example, after the intervention stage, students began to think about the title, and to use their own background knowledge to comprehend the text. The students employed, also, linguistic strategies such as decoding and, above all, the students abandoned the behaviour of reading for pronunciation in favour of reading for meaning. Despite the apparent efficacy of the alternative method, there are, inevitably, limitations related to the small-scale nature of the study and the time I had available to conduct the research. There are challenges, too, related to the students’ first language, the idiosyncrasies of the English language, the teacher training and continuing professional development of teachers, and the continuing political instability of Libya. The students’ lack of vocabulary and their difficulties with grammatical functions such as phrasal and prepositional verbs, forms which do not exist in Arabic, mean that REFL will always be challenging. Given such constraints, the ‘new’ methods I trialled and propose for adoption can only go so far in addressing students’ difficulties in REFL. Overall, the study indicates that the Libyan educational system is underdeveloped and under resourced with respect to REFL. My data indicates that the teacher participants have received little to no professional developmental that could help them improve their teaching in REFL and skills in teaching EFL. These circumstances, along with the perennial problem of large but varying class sizes; student, teacher and assessment expectations; and limited and often poor quality resources, affect the way EFL students learn to read in English. Against this background, the thesis concludes by offering tentative conclusions; reflections on the study, including a discussion of its limitations, and possible recommendations designed to improve REFL learning and teaching in Libyan universities.

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This thesis describes a collection of studies into the electrical response of a III-V MOS stack comprising metal/GaGdO/GaAs layers as a function of fabrication process variables and the findings of those studies. As a result of this work, areas of improvement in the gate process module of a III-V heterostructure MOSFET were identified. Compared to traditional bulk silicon MOSFET design, one featuring a III-V channel heterostructure with a high-dielectric-constant oxide as the gate insulator provides numerous benefits, for example: the insulator can be made thicker for the same capacitance, the operating voltage can be made lower for the same current output, and improved output characteristics can be achieved without reducing the channel length further. It is known that transistors composed of III-V materials are most susceptible to damage induced by radiation and plasma processing. These devices utilise sub-10 nm gate dielectric films, which are prone to contamination, degradation and damage. Therefore, throughout the course of this work, process damage and contamination issues, as well as various techniques to mitigate or prevent those have been investigated through comparative studies of III-V MOS capacitors and transistors comprising various forms of metal gates, various thicknesses of GaGdO dielectric, and a number of GaAs-based semiconductor layer structures. Transistors which were fabricated before this work commenced, showed problems with threshold voltage control. Specifically, MOSFETs designed for normally-off (VTH > 0) operation exhibited below-zero threshold voltages. With the results obtained during this work, it was possible to gain an understanding of why the transistor threshold voltage shifts as the gate length decreases and of what pulls the threshold voltage downwards preventing normally-off device operation. Two main culprits for the negative VTH shift were found. The first was radiation damage induced by the gate metal deposition process, which can be prevented by slowing down the deposition rate. The second was the layer of gold added on top of platinum in the gate metal stack which reduces the effective work function of the whole gate due to its electronegativity properties. Since the device was designed for a platinum-only gate, this could explain the below zero VTH. This could be prevented either by using a platinum-only gate, or by matching the layer structure design and the actual gate metal used for the future devices. Post-metallisation thermal anneal was shown to mitigate both these effects. However, if post-metallisation annealing is used, care should be taken to ensure it is performed before the ohmic contacts are formed as the thermal treatment was shown to degrade the source/drain contacts. In addition, the programme of studies this thesis describes, also found that if the gate contact is deposited before the source/drain contacts, it causes a shift in threshold voltage towards negative values as the gate length decreases, because the ohmic contact anneal process affects the properties of the underlying material differently depending on whether it is covered with the gate metal or not. In terms of surface contamination; this work found that it causes device-to-device parameter variation, and a plasma clean is therefore essential. This work also demonstrated that the parasitic capacitances in the system, namely the contact periphery dependent gate-ohmic capacitance, plays a significant role in the total gate capacitance. This is true to such an extent that reducing the distance between the gate and the source/drain ohmic contacts in the device would help with shifting the threshold voltages closely towards the designed values. The findings made available by the collection of experiments performed for this work have two major applications. Firstly, these findings provide useful data in the study of the possible phenomena taking place inside the metal/GaGdO/GaAs layers and interfaces as the result of chemical processes applied to it. In addition, these findings allow recommendations as to how to best approach fabrication of devices utilising these layers.

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In a professional and business-social context such as that of global hotel brands in the United Kingdom, intercultural communication, contacts and relationships are found at the heart of daily operations and of customer service. A large part of the clientele base of hotels in the United Kingdom is formed by individuals who belong to different cultural groups that travel in the country either for leisure or business. At the same time, the global workforce which is recruited in the hotel industry in the United Kingdom is a reality here to stay. Global travelling and labor work mobility are phenomena which have been generated by changes which occur on a socio-economic, cultural and political level due to the phenomenon of globalization. The hotel industry is therefore well acquainted with the essence of different cultures either to be accommodated within hotel premises, as in the case of external customers, or of diversity management where different cultures are recruited in the hotel industry, as in the case of internal customers. This thesis derives from research conducted on eight different global hotel brands in the United Kingdom in particular, with reference to three, four and five star categories. The research aimed to answer the question of how hotels are organized in order to address issues of intercultural communication during customer service and if intercultural barriers arise during the intercultural interaction of hotel staff and global customers. So as to understand how global hotel brands operate the research carried out focused in three main areas relating to each hotel: organizational culture, customer service–customer care and intercultural issues. The study utilized qualitative interviews with hotel management staff and non-management staff from different cultural backgrounds, public space observations between customers and staff during check-in and checkout in the reception area and during dining at the café-bar and restaurant. Thematic analysis was also applied to the official web page of each hotel and to job advertisements to enhance the findings from the interviews and the observations. For the process of analysis of the data interpretive (hermeneutic) phenomenology of Martin Heidegger has been applied. Generally, it was found that hotel staff quite often feel perplexed by how to deal with and how to overcome, for instance, language barriers and religious issues and how to interpret non verbal behaviors or matters on food culture relating to the intercultural aspect of customer service. In addition, it was interesting to find that attention to excellent customer service on the part of hotel staff is a top organizational value and customer care is a priority. Despite that, the participating hotel brands appear to have not yet, realized how intercultural barriers can affect the daily operation of the hotel, the job performance and the psychology of hotel staff. Employees indicated that they were keen to receive diversity training, provided by their organizations, so as to learn about different cultural needs and expand their intercultural skills. The notion of diversity training in global hotel brands is based on the sense that one of the multiple aims of diversity management as a practice and policy in the workplace of hotels is the better understanding of intercultural differences. Therefore global hotel brands can consider diversity training as a practice which will benefit their hotel staff and clientele base at the same time. This can have a distinctive organizational advantage for organizational affairs in the hotel industry, with potential to influence the effectiveness and performance of hotels.