Using the Internet to research hidden populations of illicit drug users : a review

Aims To review the current research of hidden populations of illicit drugs users using web-based methods and discuss major advantages and disadvantages.

Methods Systematic review of 16 databases, including PubMed, PsycINFO (EBSCOhost), CSA Sociological Abstracts, Expanded Academic ASAP and Google Scholar.

Findings Substances researched were most commonly ‘party/club drugs’ (such as ecstasy) and cannabis. All of the studies reviewed concluded that the internet is a useful tool for reaching hidden populations, but is likely to impose some bias in samples. Advantages include: access to previously under-researched target groups; speed; international applications; increased ease of data entry; and improved confidentiality for respondents. The major disadvantage is a lack of representativeness of samples.

Conclusions Internet research is successful at accessing hidden populations of illicit drugs users, when appropriately targeted and provides unprecedented opportunities for research across a wide range of topics within the addictions field. Findings are unlikely to be generalisable to the general public, but appropriate for describing target populations.

'Hidden differences : new meanings in adaptations of literature to the screen'

Approaches to screen adaptation which either accept or reject 'fidelity' effectively hide from view the interrelations of difference that can be observed between literary and visual works of art. Further, comparative reading of a literary precursor and its screen adaptation alone hides from view the interrelations of difference between those and other works. By focussing on difference, screen adaptations can be viewed and read together with literary precursors and other intertextual influences to produce new stories that would otherwise remain hidden. This method of textual analysis, 'differential reading', is explained by reference to three screen adaptations, clustered around themes of unrequited love and rejection, which illustrate general insights into theoretical issues. When viewed and read together, differences can be observed between these works which produce new meanings. When one switches between the possibilities such new meanings create, views of the world embedded in the respective works are destabilised.

Hidden stories : listening to the audience at the live performance

This paper explores how audiences describe and evaluate their experience of a live performance. Much of the arts marketing literature measures audience satisfaction with the entire event, including pre and post show talks, parking, ticket price, seating, merchandise and refreshments. Research undertaken at a range of live performing arts events in 2008 and 2009 revealed ‘hidden stories’ of audience members’ responses to performances. These responses are indicative of four aspects of the audience experience – knowledge, risk, authenticity and collective engagement. The stories, and their indicators, are the audience measure of quality of performance. This paper uses audience research at three contemporary theatre companies, to test and validate the audience experience as a new quality assessment instrument: the Arts Audience Experience Index.

‘Coded in a code of the world' : minor literature and the time-image hidden in Janet Frame’s late fiction?

This article seeks to demonstrate how Janet Frame’s late fiction can be read as a theoretical engagement with the conceptual investigations of Gilles Deleuze and Félix Guattari, especially the notions of minor literature and the in her late novels Living in the Maniototo (1981) and The Carpathians (1989). For this reason, my approach must be sharply distinguished from a more commonplace analogical framing of Frame or a simple one-to-one translation of her fiction into alternative terms. By weaving theory through her fiction, Frame makes a significant contribution to literature that responds to the still-emerging field of Deleuzean literary critical theory.

Behind the mask : the hidden struggle of parenthood

A dvd presentation of the debilitating and often secretive issue of post-natal depression and anxiety, featuring people who have personally experienced and overcome the conditions as well as insights from health professionals.

On the mopfloor: researching employment relations in the hidden world of commercial cleaning

This chapter explores some of the challenges and tribulations of studying the hidden and hitherto unresearched world of work in the New South Wales (Australia) cleaning industry. The findings and analysis presented here are informed by my research into employment relations, labour management and the organisation of work in the NSW commercial cleaning industry (Ryan, 2007). This research used primarily a case study of an industry exemplar, and made extensive use of participant observation to obtain evidence on the perceived realities of work and organisation for those on the front line of cleaning work - the cleaners and their supervisors - and to understand how they make sense of their working world. The discussions and findings presented in this chapter support the use of an ethnographic approach to work, and provide some guidance as to how a participant observation study might be carried out and what might be found through the use of this method.

Theorizing normalization as hidden privilege

This chapter provides a theoretical overview of some of the ways in which the process of normalization functions as forms of hidden privilege. It outlines how privileged groups come to represent the dominant norm whereby white, male, able-bodied, heterosexual, middle-class people in Western societies come to embody what it means to be normal. It also explores strategies for challenging the normalization of privilege by encouraging the development of responsibility not only for individual actions but also for the social practices which create them.

Gen Y and their 'backpacks of hidden treasures'

This paper reports on part of a teacher/researcher’s PhD action research study conducted in an Australian public high school, investigating the use of online social networking as a classroom learning environment where students were encouraged to find and use their hidden treasures. It examines student reactions and online activity whilst they are interacting with a range of Web 2.0 and social media tools. The study may inform the rising generation of higher education learners and their course developers and explores the move from passive to active learning through Gen Y’s engagement with online social media. It looks at a range of innovative practices that were made possible through using a Ning online social network as a classroom environment whilst encouraging Gen Y to take more responsibility for learning. It also looks at the pedagogical implications that come with the use of social media as they challenge traditional models of ‘instructional order’. This study primarily adopts a social constructivist approach to teaching with the focus being on learning, rather than teaching. The study found that having such a flexible curriculum environment encouraged Gen Y to share their ‘hidden treasures’ and, hence, informal classroom learning became more visible and more readily documented. Gen Y students appreciated the opportunities to publish and to gain feedback from more than their teacher alone. Students, in some cases, could be seen to be engaged in their own cycle of learning where they valued the opinion of their peers which, in turn, helped them to improve their work.

Policy recognition in the Abstract Hidden Markov Model

In this paper, we present a method for recognising an agent's behaviour in dynamic, noisy, uncertain domains, and across multiple levels of abstraction. We term this problem on-line plan recognition under uncertainty and view it generally as probabilistic inference on the stochastic process representing the execution of the agent's plan. Our contributions in this paper are twofold. In terms of probabilistic inference, we introduce the Abstract Hidden Markov Model (AHMM), a novel type of stochastic processes, provide its dynamic Bayesian network (DBN) structure and analyse the properties of this network. We then describe an application of the Rao-Blackwellised Particle Filter to the AHMM which allows us to construct an efficient, hybrid inference method for this model. In terms of plan recognition, we propose a novel plan recognition framework based on the AHMM as the plan execution model. The Rao-Blackwellised hybrid inference for AHMM can take advantage of the independence properties inherent in a model of plan execution, leading to an algorithm for online probabilistic plan recognition that scales well with the number of levels in the plan hierarchy. This illustrates that while stochastic models for plan execution can be complex, they exhibit special structures which, if exploited, can lead to efficient plan recognition algorithms. We demonstrate the usefulness of the AHMM framework via a behaviour recognition system in a complex spatial environment using distributed video surveillance data.

Tracking and surveillance in wide-area spatial environments using the abstract hidden markov model.

In this paper, we consider the problem of tracking an object and predicting the object's future trajectory in a wide-area environment, with complex spatial layout and the use of multiple sensors/cameras. To solve this problem, there is a need for representing the dynamic and noisy data in the tracking tasks, and dealing with them at different levels of detail. We employ the Abstract Hidden Markov Models (AHMM), an extension of the well-known Hidden Markov Model (HMM) and a special type of Dynamic Probabilistic Network (DPN), as our underlying representation framework. The AHMM allows us to explicitly encode the hierarchy of connected spatial locations, making it scalable to the size of the environment being modeled. We describe an application for tracking human movement in an office-like spatial layout where the AHMM is used to track and predict the evolution of object trajectories at different levels of detail.

The hidden permutation model and location-based activity recognition

Permutation modeling is challenging because of the combinatorial nature of the problem. However, such modeling is often required in many real-world applications, including activity recognition where subactivities are often permuted and partially ordered. This paper introduces a novel Hidden Permutation Model (HPM) that can learn the partial ordering constraints in permuted state sequences. The HPM is parameterized as an exponential family distribution and is flexible so that it can encode constraints via different feature functions. A chain-flipping Metropolis-Hastings Markov chain Monte Carlo (MCMC) is employed for inference to overcome the O(n!) complexity. Gradient-based maximum likelihood parameter learning is presented for two cases when the permutation is known and when it is hidden. The HPM is evaluated using both simulated and real data from a location-based activity recognition domain. Experimental results indicate that the HPM performs far better than other baseline models, including the naive Bayes classifier, the HMM classifier, and Kirshner's multinomial permutation model. Our presented HPM is generic and can potentially be utilized in any problem where the modeling of permuted states from noisy data is needed.

Human behavior recognition with generic exponential family duration modeling in the hidden semi-Markov model

The ability to learn and recognize human activities of daily living (ADLs) is important in building pervasive and smart environments. In this paper, we tackle this problem using the hidden semi-Markov model. We discuss the state-of-the-art duration modeling choices and then address a large class of exponential family distributions to model state durations. Inference and learning are efficiently addressed by providing a graphical representation for the model in terms of a dynamic Bayesian network (DBN). We investigate both discrete and continuous distributions from the exponential family (Poisson and Inverse Gaussian respectively) for the problem of learning and recognizing ADLs. A full comparison between the exponential family duration models and other existing models including the traditional multinomial and the new Coxian are also presented. Our work thus completes a thorough investigation into the aspect of duration modeling and its application to human activities recognition in a real-world smart home surveillance scenario.

Activity recognition and abnormality detection with the switching hidden semi-Markov model

This paper addresses the problem of learning and recognizing human activities of daily living (ADL), which is an important research issue in building a pervasive and smart environment. In dealing with ADL, we argue that it is beneficial to exploit both the inherent hierarchical organization of the activities and their typical duration. To this end, we introduce the Switching Hidden Semi-Markov Model (S-HSMM), a two-layered extension of the hidden semi-Markov model (HSMM) for the modeling task. Activities are modeled in the S-HSMM in two ways: the bottom layer represents atomic activities and their duration using HSMMs; the top layer represents a sequence of high-level activities where each high-level activity is made of a sequence of atomic activities. We consider two methods for modeling duration: the classic explicit duration model using multinomial distribution, and the novel use of the discrete Coxian distribution. In addition, we propose an effective scheme to detect abnormality without the need for training on abnormal data. Experimental results show that the S-HSMM performs better than existing models including the flat HSMM and the hierarchical hidden Markov model in both classification and abnormality detection tasks, alleviating the need for presegmented training data. Furthermore, our discrete Coxian duration model yields better computation time and generalization error than the classic explicit duration model.