Growth of epitaxial silicon layers by ion beam sputtering

Imperial Users onl

Mobile Audiovisual Terminal: System Design and Subjective Testing in DECT and UMTS networks

It is anticipated that there will shortly be a requirement for multimedia terminals that operate via mobile communications systems. This paper presents a functional specification for such a terminal operating at 32 kb/s in a digital European cordless telecommunications (DECT) and universal mobile telecommunications system (UMTS) radio network. A terminal has been built, based on a PC with digital signal processor (DSP) boards for audio and video coding and decoding. Speech coding is by a phonetically driven code-excited linear prediction (CELP) speech coder and video coding by a block-oriented hybrid discrete cosine transform (DCT) coder. Separate channel coding is provided for the audio and video data. The paper describes the techniques used for audio and video coding, channel coding, and synchronization. Methods of subjective testing in a DECT network and in a UMTS network are also described. These consisted of subjective tests of first impressions of the mobile audio–visual terminal (MAVT) quality, interactive tests, and the completion of an exit questionnaire. The test results showed that the quality of the audio was sufficiently good for comprehension and the video was sufficiently good for following and repeating simple mechanical tasks. However, the quality of the MAVT was not good enough for general use where high-quality audio and video was needed, especially when transmission was in a noisy radio environment

Parallel H.263 Encoder in Normal Coding Mode

A parallel H.263 video encoder, which utilises spatial para1 elism, has been modelled using a multi-threaded program. Spatial parallelism is a technique where an image is subdivided into equal parts (as far as physically possible) and each part is proces!;ed by a separate processor by computing motion and texture mding with all processors cach acting on a different part of thc ]mag. This method leads to a performance increase, which is roughly in proportion to the number of parallel processors used

Manufacturing

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The measurement of passenger preferences towards rail station and on-train facilities

This study is concerned with the provision of passenger facilities, such as catering or information, at rail stations and on trains. It takes the premise that appraisal methods vised by rail operators and planners for evaluating investment in such facilities are limited. The result can be under-investment in such facilities. It makes the case that such facilities are important devices for inproving the quality of rail travel and that under-investment in facilities implies reduced demand for rail services. It is suggested that stated preference (SP) techniques, already applied to this topic on a number of occasions, are effective methods for measuring the monetary equivalent values of passenger facilities. These values can be inserted into investment appraisal methods based on financial criteria or cost-benefit analysis. However, previous applications of SP techniques have exhibited a number of weaknesses, which have called into question the plausibility of some of the values that have been obtained. This study reports on research on the London Underground, investigating the potential introduction of a range of improvements to passenger facilities on the Northern Line. In this original work, discrete choice SP methods were used to measure the values of these improvements in a way that will produce more plausible results, it is argued, than those derived from earlier SP applications. The research showed that appreciably lower valuations were obtained with this method

Authenticity: an ethic of capacity realisation

My interests lie in consideration of conceptions of authenticity and inauthenticity from the perspective of ethical theories which conceive of the good for man with reference to human nature and concomitant beliefs regarding the most appropriate realisation of human capacities. Here, I find particular interest in the philosophical styles embodied by the existentialist and Lebensphilosophie movements. Such approaches sit outside the traditional frames of reference provided by deontological and utilitarian approaches to ethical reasoning and yet do I shall argue, share significant similarities with ancient aretaic styles of ethics. Here, I take Aristotle to represent those aspects of ethical thought which are quintessentially of this period of intellectual history. I find not merely points of comparison but a fruitful way in which to re-examine the thought of thinkers such as Nietzsche, Scheler, Heidegger and Sartre with reference to styles of ethical enquiry which place primacy upon an objective conception of happiness which centres upon the appropriate realisation of human capacity understood with reference to Aristotle's Function Argument. I argue that phenomenological analysis shares a conception of self-perspicuity in which the agent reflects upon the full contents of their conscious experience. By this means, certain self-delusions which impede entry into the ethical life, may be removed. Additionally, whilst Aristotle's 'non-law' conception of ethics shares with existentialist thought an understanding of the human situation and its normative concerns in isolation from dualistic and theistic metaphysical speculation, such philosophy is still able to provide clear and objective ethical standards - standards often lacking within existentialism. For instance, whilst Nietzsche's pronouncement of the 'death of God' signals the death also of Christian morality, we find that such philosophy is not without normative implications and in fact can be derived to a large degree from assent towards a radical and more severe ethical self-discipline. Indeed, central certainly to the thought of Nietzsche, Heidegger and Sartre is an understanding of the role of self-deception in the human condition. Here a useful distinction may be made between those types of self-deception which may be understood as structural that is to say which are representative of an essential characteristic of human being at the abstract level - and those types of self-deception which may be described as 'motivated' or 'psychological' which relate to more specific types of self-deceptive engagement. I believe it is useful to examine both Nietzsche, Heidegger and Sartre through the lens of such interpretation, I find for instance that it is of use to examine the early Sartre as having a purely structural interpretation of bad faith (described by Jeanson as 'natural' bad-faith) whilst moving towards a psychological account in his later work, an account which has more specific moral implications with the possibility of 'willed conversion' to authenticity (Santoni). Additionally with Nietzsche, we also find a similar distinction between a self-deception which is in some sense preconditional and a motivational account of self-deception in which the agent infused with ressentiment falsifies reality in favour of subjective needs which are ultimately destructive of life-enhancement. In this sense the vicious individual can be said to have achieved merely a false optimum, and moreover, false from an objective standpoint

Authenticity : an ethic of capacity realisation

My interests lie in consideration of conceptions of authenticity and inauthenticity from the perspective of ethical theories which conceive of the good for man with reference to human nature and concomitant beliefs regarding the most appropriate realisation of human capacities. Here, I find particular interest in the philosophical styles embodied by the existentialist and Lebensphilosophie movements. Such approaches sit outside the traditional frames of reference provided by deontological and utilitarian approaches to ethical reasoning and yet do I shall argue, share significant similarities with ancient aretaic styles of ethics. Here, I take Aristotle to represent those aspects of ethical thought which are quintessentially of this period of intellectual history. I find not merely points of comparison but a fruitful way in which to re-examine the thought of thinkers such as Nietzsche, Scheler, Heidegger and Sartre with reference to styles of ethical enquiry which place primacy upon an objective conception of happiness which centres upon the appropriate realisation of human capacity understood with reference to Aristotle's Function Argument. I argue that phenomenological analysis shares a conception of self-perspicuity in which the agent reflects upon the full contents of their conscious experience. By this means, certain self-delusions which impede entry into the ethical life, may be removed. Additionally, whilst Aristotle's 'non-law' conception of ethics shares with existentialist thought an understanding of the human situation and its normative concerns in isolation from dualistic and theistic metaphysical speculation, such philosophy is still able to provide clear and objective ethical standards - standards often lacking within existentialism. For instance, whilst Nietzsche's pronouncement of the 'death of God' signals the death also of Christian morality, we find that such philosophy is not without normative implications and in fact can be derived to a large degree from assent towards a radical and more severe ethical self-discipline. Indeed, central certainly to the thought of Nietzsche, Heidegger and Sartre is an understanding of the role of self-deception in the human condition. Here a useful distinction may be made between those types of self-deception which may be understood as structural that is to say which are representative of an essential characteristic of human being at the abstract level - and those types of self-deception which may be described as 'motivated' or 'psychological' which relate to more specific types of self-deceptive engagement. I believe it is useful to examine both Nietzsche, Heidegger and Sartre through the lens of such interpretation, I find for instance that it is of use to examine the early Sartre as having a purely structural interpretation of bad faith (described by Jeanson as 'natural' bad-faith) whilst moving towards a psychological account in his later work, an account which has more specific moral implications with the possibility of 'willed conversion' to authenticity (Santoni). Additionally with Nietzsche, we also find a similar distinction between a self-deception which is in some sense preconditional and a motivational account of self-deception in which the agent infused with ressentiment falsifies reality in favour of subjective needs which are ultimately destructive of life-enhancement. In this sense the vicious individual can be said to have achieved merely a false optimum, and moreover, false from an objective standpoint.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Flash sintering of injection molded zirconia under AC electric field for enhancement of optical properties

Zirconia is a very versatile ceramic material used in many applications, from structural components to healthcare implantable parts. The majority of current flash research has been performed using uniaxial pressed samples. In our research, we looked to study a large-scale manufacturing technique to produce the samples to be sintered. Ceramic injection molding (CIM) is a known method to produce complex shaped parts with great precision and high density. The high binder content in CIM parts can cause difficulty during flash sintering, due to the high porosity left after debinding process. This can cause localization and flashover during the application of the electric field. Commercially injection molded partially stabilized zirconia (3YSZ) was chosen as it has important properties, such high fracture toughness, however, it is usually opaque due to inherent microstructure defects and grain size of the material. For many applications, zirconia, does not require a particular color or specific appearance, but in some cases for aesthetic uses, a transparent-like material is highly desirable. This paper will describe the results on flash sintering equipment design and field parameters used in order to optimize levels of translucency in zirconia disks, with high fracture toughness. The flash sintering process is shown to be repeatable, and is compared with conventionally sintered samples to assess the improvement on translucency and/or fracture toughness. It is then proposed that flash sintering is an enabling mechanism for the use of zirconia in a wider range of applications and markets, where aesthetics and toughness are required in parallel

Perfect design or practical study? A workshop on navigating the challenges of community based prevention research

Subject: There is a shared interest among public health researchers in tackling methodological issues surrounding community based research, and on moving beyond a focus on individual level change. As part of a project on community empowerment funded by the People’s Health Trust, we have conducted a feasibility study on quantitative and economic evaluation of complex community-based interventions. To understand different quantitative methods that can be used to evaluate community empowerment interventions, we have undertaken a methodological literature review that identified the following sets of challenges: Defining population of interest – interventions taking place at a community level are not specifically targeted at a well-defined group of individuals. Therefore it is challenging to even find those who are affected by an intervention. Diverse and un-prescribed effects – the effect of community empowerment interventions are likely broad, suggesting we need to measure multiple outcomes in order to detect change. This increases the likelihood of detecting spurious change and can require a lot of resource. Furthermore, in many cases these outcomes are not pre-defined by a programme (i.e. communities choose their own foci)