Evaluation of sampling methods for learning from imbalanced data

The problem of learning from imbalanced data is of critical importance in a large number of application domains and can be a bottleneck in the performance of various conventional learning methods that assume the data distribution to be balanced. The class imbalance problem corresponds to dealing with the situation where one class massively outnumbers the other. The imbalance between majority and minority would lead machine learning to be biased and produce unreliable outcomes if the imbalanced data is used directly. There has been increasing interest in this research area and a number of algorithms have been developed. However, independent evaluation of the algorithms is limited. This paper aims at evaluating the performance of five representative data sampling methods namely SMOTE, ADASYN, BorderlineSMOTE, SMOTETomek and RUSBoost that deal with class imbalance problems. A comparative study is conducted and the performance of each method is critically analysed in terms of assessment metrics. © 2013 Springer-Verlag.

Future trends in cystic fibrosis demography in 34 European countries

Median survival has increased in people with cystic fibrosis (CF) during the past six decades, which has led to an increased number of adults with CF. The future impact of changes in CF demographics has not been evaluated. The aim of this study was to estimate the number of children and adults with CF in 34 European countries by 2025. Data were obtained from the European Cystic Fibrosis Society Patient Registry. Population forecasts were performed for countries that have extensive CF population coverage and at least 4 years of longitudinal data by modelling future entering and exiting flows in registry cohorts. For the other countries, population projections were performed based on assumptions from knowledge of current CF epidemiology. Western European countries' forecasts indicate that an increase in the overall number of CF patients by 2025, by approximately 50%, corresponds to an increase by 20% and by 75% in children and adults, respectively. In Eastern European countries the projections suggest a predominant increase in the CF child population, although the CF adult population would also increase.It was concluded that a large increase in the adult CF population is expected in the next decade. A significant increase in adult CF services throughout Europe is urgently required.

The Teaching Space Allocation Problem with splitting

A standard problem within universities is that of teaching space allocation which can be thought of as the assignment of rooms and times to various teaching activities. The focus is usually on courses that are expected to fit into one room. However, it can also happen that the course will need to be broken up, or ‘split’, into multiple sections. A lecture might be too large to fit into any one room. Another common example is that of seminars or tutorials. Although hundreds of students may be enrolled on a course, it is often subdivided into particular types and sizes of events dependent on the pedagogic requirements of that particular course. Typically, decisions as to how to split courses need to be made within the context of limited space requirements. Institutions do not have an unlimited number of teaching rooms, and need to effectively use those that they do have. The efficiency of space usage is usually measured by the overall ‘utilisation’ which is basically the fraction of the available seat-hours that are actually used. A multi-objective optimisation problem naturally arises; with a trade-off between satisfying preferences on splitting, a desire to increase utilisation, and also to satisfy other constraints such as those based on event location and timetabling conflicts. In this paper, we explore such trade-offs. The explorations themselves are based on a local search method that attempts to optimise the space utilisation by means of a ‘dynamic splitting’ strategy. The local moves are designed to improve utilisation and satisfy the other constraints, but are also allowed to split, and un-split, courses so as to simultaneously meet the splitting objectives.

British drugs policy: Problematizing the distinction between legal and illegal drugs and the definition of the ‘drugs problem’.

This article draws upon an extensive literature review of the social and medical sciences, official documents and various websites to critically re-evaluate the basis of British drugs policy. The article problematizes the rationale for criminalizing certain substances and questions the distinctions created between legal and illegal drugs; in so doing, the article argues that the definition of the `drugs problem' is the real problem. It shows that the debate on illegal drugs is filled less with factual truths and more with misinformation which creates public fear and provides a questionable basis for public policy. The article questions current thinking regarding the drugs/crime relationship and concludes by exploring some implications for policy and practice.

The SDLP and the Europeanization of the Northern Ireland Problem

This article explores the various ways in which the Social Democratic and Labour Party (SDLP) has used Europe – as a source of financial aid, political support, ideas and inspiration – in its attempts to resolve the Northern Ireland conflict. In this, the piece considers the SDLP, not as a subject, but rather as an advocate of the Europeanization of the Northern Ireland problem. In particular, it looks at the role of John Hume, a founding member and later leader of the SDLP, who inculcated a strongly pro-European outlook within the party. In doing so, the article considers the success of Hume and the SDLP in their efforts to bring a European influence to bear on Northern Ireland, especially in relation to the peace process and the 1998 Agreement. However, it also looks at both the limitations of this influence, and the problems involved with the SDLP's pro-European approach, particularly since Hume's departure as party leader in 2001. In conclusion, the article suggests that the party may have been ‘over-Europeanized’, with its long-term focus on European issues and ideas now becoming electorally disadvantageous. In this way, the Europeanization of the Northern Ireland problem, and by extension the SDLP, has proven costly to the party.