Feature placement algorithms for high-variability applications in cloud environments

While the use of cloud computing is on the rise, many obstacles to its adoption remain. One of the weaknesses of current cloud offerings is the difficulty of developing highly customizable applications while retaining the increased scalability and lower cost offered by the multi-tenant nature of cloud applications. In this paper we describe a Software Product Line Engineering (SPLE) approach to the modelling and deployment of customizable Software as a Service (SaaS) applications. Afterwards we define a formal feature placement problem to manage these applications, and compare several heuristic approaches to solve the problem. The scalability and performance of the algorithms is investigated in detail. Our experiments show that the heuristics scale and perform well for systems with a reasonable load

Interstitial laser photocoagulation as a treatment for breast cancer

Conservative surgery is a safe alternative to mastectomy for some patients with breast cancer. A survey of surgeons in this thesis has shown that more surgeons would now undertake conservative surgery than they have done in the past. Recently a new technique, interstitial laser photocoagulation(ILP) has been described which is capable of in situ tissue necrosis with safe healing. The idea of ILP takes the concept of conservative surgery for breast cancer a step further. The main purpose of this thesis was to investigate the potential value of ILP as a future method of destroying breast cancers in situ leaving the area to heal via resorption and fibrosis. The aims of this thesis were to study the biology of laser interactions with breast cancers scheduled for surgery(and not to completely destroy the tumour), to optimise the laser parameters of power and exposure for a particular tumour and to find an imaging technique which will accurately predict the extent of laser damage. Forty five patients were treated with ILP prior to surgery(median 7 days). Tumour necrosis varied from 2-25mm. No laser damage was noted in 4 patients. Two patients developed minor complications and treatment was abandoned early due to pain in a further 4 patients. The presence of charring within the tumour was associated with larger diameters of necrosis than when charring was absent(median 13 vs 6 mm, p=0.002) and use of a precharred fibre produced similar lesions(median 14mm) which were more predictable.The histological features in the tumour following ILP were of coagulative necrosis which appeared to heal by the formation of fibrous tissue. An area of heat fixed, morphologically preserved tissue was noted within the zone of coagulative necrosis which was thought to be non-viable. Ultrasonography, Com puterised Tomography(CT) and M agnetic Resonace Imaging(MRI) were all used to monitor necrosis. Ultrasound was unable to predict the extent of necrosis as measured in the resected specimen(r=0.3, p=N.S.) but was reasonable at predicting tumour size(r=0.6, p=0.001). CT and MRI show some promise but were only investigated in small numbers of patients. This study has shown that ILP is simple and safe and when using a pre-charred fibre, predictable. If the initial results of imaging using CT and MRI are confirmed in larger studies then ILP could possibly have a role in the treatment of small breast cancers

Personalised Learning: Developing a Vygotskian Framework for E-learning

Personalisation has emerged as a central feature of recent educational strategies in the UK and abroad. At the heart of this is a vision to empower learners to take more ownership of their learning and develop autonomy. While the introduction of digital technologies is not enough to effect this change, embedding the affordances of new technologies is expected to offer new routes for creating personalised learning environments. The approach is not unique to education, with consumer technologies offering a 'personalised' relationship which is both engaging and dynamic, however the challenge remains for learning providers to capture and transpose this to educational contexts. As learners begin to utilise a range of tools to pursue communicative and collaborative actions, the first part of this paper will use analysis of activity logs to uncover interesting trends for maturing e-learning platforms across over 100 UK learning providers. While personalisation appeals to marketing theories this paper will argue that if learning is to become personalised one must ask what the optimal instruction for any particular learner is? For Vygotsky this is based in the zone of proximal development, a way of understanding the causal-dynamics of development that allow appropriate pedagogical interventions. The second part of this paper will interpret personalised learning as the organising principle for a sense-making framework for e-learning. In this approach personalised learning provides the context for assessing the capabilities of e-learning using Vygotsky’s zone of proximal development as the framework for assessing learner potential and development