35 research outputs found
Machine Learning in Automated Text Categorization
The automated categorization (or classification) of texts into predefined
categories has witnessed a booming interest in the last ten years, due to the
increased availability of documents in digital form and the ensuing need to
organize them. In the research community the dominant approach to this problem
is based on machine learning techniques: a general inductive process
automatically builds a classifier by learning, from a set of preclassified
documents, the characteristics of the categories. The advantages of this
approach over the knowledge engineering approach (consisting in the manual
definition of a classifier by domain experts) are a very good effectiveness,
considerable savings in terms of expert manpower, and straightforward
portability to different domains. This survey discusses the main approaches to
text categorization that fall within the machine learning paradigm. We will
discuss in detail issues pertaining to three different problems, namely
document representation, classifier construction, and classifier evaluation.Comment: Accepted for publication on ACM Computing Survey
What is a vector?
Many important and rapidly emerging pathogens of humans, livestock and wildlife are âvector-borneâ. However, the term âvectorâ has been applied to diverse agents in a broad range of epidemiological systems. In this perspective, we briefly review some common definitions, identify the strengths and weaknesses of each and consider the functional differences between vectors and other hosts from a range of ecological, evolutionary and public health perspectives. We then consider how the use of designations can afford insights into our understanding of epidemiological and evolutionary processes that are not otherwise apparent. We conclude that from a medical and veterinary perspective, a combination of the âhaematophagous arthropodâ and âmobilityâ definitions is most useful because it offers important insights into contact structure and control and emphasizes the opportunities for pathogen shifts among taxonomically similar species with similar feeding modes and internal environments. From a population dynamics and evolutionary perspective, we suggest that a combination of the âmicropredatorâ and âsequentialâ definition is most appropriate because it captures the key aspects of transmission biology and fitness consequences for the pathogen and vector itself. However, we explicitly recognize that the value of a definition always depends on the research question under study. This article is part of the themed issue âOpening the black box: re-examining the ecology and evolution of parasite transmissionâ
Charting a theoretical framework for examining Indigenous journalism culture
Indigenous media around the globe have expanded considerably in recent years, a process that has also led to an increase in the number of Indigenous news organisations. Yet, research into Indigenous news and journalism is still rare, with mostly individual case studies having been undertaken in different parts of the globe. Drawing on existing research gathered from a variety of global contexts, this paper theorises five main dimensions which can help us think about and empirically examine Indigenous journalism culture. They include: the empowerment role of Indigenous journalism; the ability to offer a counter-narrative to mainstream media reporting; journalismâs role in language revitalisation; reporting through a culturally appropriate framework; and the watchdog function of Indigenous journalism. These dimensions are discussed in some detail, in an attempt to guide future studies into the structures, roles, practices and products of Indigenous journalism across the globe
A guide for ecologists: Detecting the role of disease in faunal declines and managing population recovery
Biodiversity is declining at an alarming rate, especially among vertebrates. Disease is commonly ignored or dismissed in investigations of wildlife declines, partly because there is often little or no obvious clinical evidence of illness. We argue that disease has the potential to cause many species declines and extinctions and that there is mounting evidence that this is a more important cause of declines than has been appreciated. We summarise case studies of diseases that have affected wildlife to the point of extinction and bring together the experiences of wildlife managers, veterinarians, epidemiologists, infectious disease specialists, zoologists and ecologists to provide an investigation framework to help ecologists and wildlife managers address disease as a factor in wildlife declines. Catastrophic declines of wildlife may be the result of single or multiple synergistic causes, and disease should always be one factor under consideration, unless proven otherwise. In a rapidly changing world where emerging infectious diseases have become increasingly common, the need to consider diseases has never been more important