Effectiveness of landmark analysis for establishing locality in p2p networks

Locality to other nodes on a peer-to-peer overlay network can be established by means of a set of landmarks shared among the participating nodes. Each node independently collects a set of latency measures to landmark nodes, which are used as a multi-dimensional feature vector. Each peer node uses the feature vector to generate a unique scalar index which is correlated to its topological locality. A popular dimensionality reduction technique is the space filling Hilbert’s curve, as it possesses good locality preserving properties. However, there exists little comparison between Hilbert’s curve and other techniques for dimensionality reduction. This work carries out a quantitative analysis of their properties. Linear and non-linear techniques for scaling the landmark vectors to a single dimension are investigated. Hilbert’s curve, Sammon’s mapping and Principal Component Analysis have been used to generate a 1d space with locality preserving properties. This work provides empirical evidence to support the use of Hilbert’s curve in the context of locality preservation when generating peer identifiers by means of landmark vector analysis. A comparative analysis is carried out with an artificial 2d network model and with a realistic network topology model with a typical power-law distribution of node connectivity in the Internet. Nearest neighbour analysis confirms Hilbert’s curve to be very effective in both artificial and realistic network topologies. Nevertheless, the results in the realistic network model show that there is scope for improvements and better techniques to preserve locality information are required.

Sustainable refurbishment: quantifying the impact of façade changes in multi-storey, multi-occupancy buildings

Building refurbishment is key to reducing the carbon footprint and improving comfort in the built environment. However, quantifying the real benefit of a facade change, which can bring advantages to owners (value), occupants (comfort) and the society (sustainability), is not a simple task. At a building physics level, the changes in kWh per m2 of heating / cooling load can be readily quantified. However, there are many subtle layers of operation and mainte-nance below these headline figures which determine how sustainable a building is in reality, such as for example quality of life factors. This paper considers the range of approached taken by a fa/e refurbishment consortium to assess refurbishment solutions for multi-storey, multi-occupancy buildings and how to critically evaluate them. Each of the applued tools spans one or more of the three building parameters of people, product and process. 'De-cision making' analytical network process and parametric building analysis tools are described and their potential impact on the building refurbishment process evaluated.

Bringing the target to the cursor: proxy targets for older adults

Studies in the literature have proposed techniques to facilitate pointing in graphical user interfaces through the use of proxy targets. Proxy targets effectively bring the target to the cursor, thereby reducing the distance that the cursor must travel. This paper describes a study which aims to provide an initial understanding of how older adults respond to proxy targets, and compares older with younger users. We found that users in both age groups adjusted to the proxy targets without difficulty, and there was no indication in the cursor trajectories that users were confused about which target, i.e. the original versus the proxy, was to be selected. In terms of times, preliminary results show that for younger users, proxies did not provide any benefits over direct selection, while for older users, times were increased with proxy targets. A full analysis of the movement times, error rates, throughput and subjective feedback is currently underway.

Factors influencing the use of antitumoral chemotherapy in the South East of England

Influences on the use of chemotherapy for the treatment of cancer within the South East region of England for patients diagnosed with colorectal, lung, breast and prostate cancer were investigated. The variables investigated as possibly influencing the selection of chemotherapy were the sex of the patients, their age, the year of diagnosis, the cancer site, the cancer stage, the index of multiple deprivation (IMD) and the cancer network of residence. Logistic regression used to adjust the proportion receiving chemotherapy in relation to other variables considered showed significant differences in the proportion of patients receiving chemotherapy between different cancer sites and different networks. There was also a highly significant trend seen in use of chemotherapy over time; the adjusted proportion of patients receiving chemotherapy increasing from 10.6% in 1993 to 24.3% in 2002. Age, stage and cancer site seemed to have the most influence on the use of chemotherapy.

Teacher’s leadership in web-based language courses in Dalarna University, Sweden

The purpose of this presentation is to discuss how teacher’s leadership can be used as a teaching method in web based language education. The environments that offer online courses provide a wide field for discussion on the contact between teacher and student. My intention is to contribute to the debate on teacher leadership in online courses. In my earlier studies on leadership, I have explored how some religious leaders affected different social movements in Brazil during the military dictatorship (1964-1985). Pruth (2004) by examining the three kinds of legitimacy described by Max Weber I aimed at seeing and analyzing how religious leaders used different teaching methods to explain their messages to ordinary citizens. Thus my research showed how educational leadership is a way to get people to reach their goals. I became interested in the subject teacher’s leadership whenI participated in a survey of the teaching methods of language courses in Dalarna University which is funded by the NGL Center of Dalarna University. In  this project, we have made interviews with the teachers, undertaken the course plans (in the language department at Dalarna University) and categorized the learning outcomes. A questionnaire was constructed based on the learning outcomes and then either sent out remotely to teachers or completed face to face through interviews. The answers provided to the questionnaires enabled the  project to identify many differences in how language teachers interact with their students but  also, the way of giving feedback, motivating and helping students, types of class activities and materials used. This made me aware of how teachers use their leadership or not in their teaching. My focus is to look at the relationship between teachers and students as an important part of the development and quality of online courses. The teacher's performance on campus is different from online courses. I want to understand how the contact between teachers and students in online courses develop and look at how students can make use of this contact and what influence the teacher's leadership has on the ability for the students to achieve the goals of their course

Efeito da ciclagem mecânica sobre a resistência de união de pinos intra-radiculares de fibra cimentados com resina à dentina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)