Predictive statistical user models under the collaborative approach

Mención Internacional en el título de doctorUser models and recommender systems due to their similarity can be considered the same thing except from the use that we make of them. Both have their root in multiple disciplines such as information retrieval or machine learning among others. The impact has grown rapidly with the importance of data on systems and applications. Most of the big companies employ one of the other for different reasons such as: gathering more customers, boost sales or increase revenue. Thus very well-known companies like Amazon, EBay or Google use models to improve their businesses. In fact, as data becomes more and more important for companies, universities and people, user models are crucial to make decisions over large amounts of data. Although user models can provide accurate predictions on large populations their use and application is not restricted to predictions but can be extended to selection of dialogue strategies or detection of communities within complex domains. After a deep review of the existing literature, it was found that there is a lack of statistical user models based on experience plus the existing models in the area are content-based models that suffer from major problems as scalability, cold-start or new user problem. Furthermore, researchers in the area of user modelling usually develop their own models and then perform ad-hoc evaluations that are not replicable and therefore not comparable. The lack of a complete framework for evaluation makes very difficult to compare results across models and domains. There are two main approaches to build a user model or recommender system: the content based approach, where predictions are based on the same user past behaviours; and the collaborative approach where predictions rely on like-minded people. Both approaches have advantages but also downsides that have to be considered before building a model. The main goal of this thesis is to develop a hybrid user model that takes the strengths of both approaches and mitigates the downsides by combining both methods. The proposed hybrid model is based on an R-Tree structure. The selection of this structure to support the models is backed from the fact that the rectangle tree is specifically designed to effectively store and manipulate multidimensional data. This data structure introduced by Guttman in 1984 is a height balanced tree that only requires visiting a few nodes to perform a tree search. As a result, it can manage large populations of data efficiently as only a few nodes are visited during the inference. R-Tree has two different typologies of nodes: the leaf-node and the non-leaf node. Leaf nodes contain the whole universe of users while non leaf nodes are somehow redundant and contain summaries of child nodes. Along this thesis two statistical user models based on experience have been proposed. The first one is a knowledge base user mode (KLUM), is a classical approach that summarizes and remove data in order to keep performance level within reasonable margins. The second one, an R-Tree user model (RTUM), is an innovative model based on an R-Tree structure. This new model not only solves the problem of removing data but also the scalability problem which turns out to be one of the major problems in the area of user modelling. Both models have been developed and tested with equivalent formulations to make comparisons relevant. Both models are prepared to create their own knowledge base from scratch but also they can be fed with expert knowledge. Thus alleviating another major problem in the area of user modelling as it is the start-up problem. Regarding the proposal of this thesis, two statistical user models are proposed (KLUM and RTUM). In addition, a refinement of RTUM user model is proposed, while RTUM performs node partitions based on the centroids of the users in that node, the new refinement implements a new partition based on privileged features. Hence, the new approach takes advantage of most discriminatory features of the domain to perform the partition. This new approach not only provides accurate inferences, but also an excellent clustering that can be useful in many different scenarios. For instance, this clustering can be employed in the area of social networks to detect communities within the social network. This is a tough task that has been one of the goals of many researchers during the last few years. This thesis also provides a complete evaluation of the models with a great diversity of parameterizations and domains. The models are tested in four different domains and as a result of the evaluation, it is proved that RTUM user model provides a massive gain against classical user models as KLUM. During the evaluation, RTUM reached success rates of 85% while the analogous KLUM could only reach a 65% thus leaving a 20% gain for the proposed model. The evaluation provided not only compares models and success rates, but also provides a broad analysis of how every parameter of the models impact the performance plus a complete study of the databases sizes and inference times for the models. The main conclusion to the evaluation is that after a complete evaluation with a wide diversity of parameters and domains RTUM outperforms KLUM on every scenario tested. As previously mentioned, after the literature review it was also found a lack of evaluation frameworks for user modelling. This thesis also provides a complete evaluation framework for user modelling. This fills a gap in the literature as well as makes the evaluation replicable and therefore comparable. Along years researchers and developers had found difficulties to compare evaluations and measure the quality of their models in different domains due to the lack of an evaluation standard. The evaluation framework presented in this thesis covers data samples including training set and test set plus different sets of experiments alongside with a statistical analysis of the domain, confidence intervals and confidence levels to guarantee that each experiment is statistically significant. The evaluation framework can be downloaded and then used to complete evaluations and cross-validate results across different models.This thesis would not have been possible without the financial support of the following research projects Cadooh (TSI-020302-2011-21), Thuban (TIN2008-02711) that funded part of this research.Programa Oficial de Doctorado en Ciencia y Tecnología InformáticaPresidente: Antonio de Amescua Seco.- Secretario: Ruth Cobos Pérez.- Vocal: Dominikus Heckman

Foetal alcohol spectrum disorder: The development of guidelines to inform policy

Philosophiae Doctor - PhDIntroduction: Maternal alcohol consumption during pregnancy can result to birth defects, which may be developmental, intellectual and physical. Fetal alcohol spectrum disorder (FASD) is a term used to describe an array of disorders related to alcohol consumption during pregnancy. FASD is a severe public health problem globally, with South Africa having the highest prevalence (29 to 290 per 1000 live births). What makes the FASD problem severe in the country is rife of maternal risk factors and widespread binge drinking during pregnancy. There is no policy specifically addressing FASD despite being pervasive in South Africa. Government programmes to prevent and manage FASD remain limited and fragmental across relevant departments. Herein, we aimed to conduct a multi-method study with a modified Delphi approach to developing a guideline to inform the development of a comprehensive and multi-sectoral policy for the prevention and management of FASD. Method and analysis: We used a modified version of the World Health Organization’s approach to guideline development in three phases. In phase 1, we conducted four different studies to design the initial guideline prototype. The studies include an in-depth interview with policymakers and a focus group with relevant service providers on policy requirements for FASD, a document review of policies on FASD and a scoping review of various interventions employed for the prevention and management of FASD. The second phase involved using the initially developed guideline prototype to engage with the local and international experts on FASD for improvement on the content. In the third phase, we refined the prototype using a modified Delphi approach. Framework method and content analysis were used to analyse the qualitative data while the Statistical Package for Social Science (SPSS) software was used to analyse the quantitative data

Practice guidelines for culturally sensitive drug prevention interventions

South Africa has experienced a notable increase in adolescent drug use during the country’s transition from apartheid to democracy (Central Drug Authority [CDA], 2006). These findings are verified by epidemiological studies and two national youth risk behaviour surveys, highlighting the need for effective drug prevention interventions. Whilst drug use spans across age, gender and social strata, the rapid increase in both legal and illicit drug use among adolescents in the Northern Areas communities of Port Elizabeth has been particularly pronounced. The South African Community Epidemiology Network on Drug Use (SACENDU) statistics, which reflects on racial demographics in accordance with the Population Registration Act of 1950 (South Africa, 1950), reports that, in the year 2011, the ‘Coloured’ population constituted 62 percent of those individuals seeking treatment for drug abuse, compared to 15 percent ‘African’ treatment seekers in Port Elizabeth (Dada, Plüddemann, Parry, Bhana, Vawda & Fourie, 2012:44). Furthermore, methamphetamine use by persons under the age of 20 years in Port Elizabeth increased fivefold in a three-year period, i.e. from 7 percent in 2008 to 39 percent in 2011 (Dada et al., 2012), with the ‘Coloured’ population group accounting for the majority of methamphetamine users. These statistics reinforce a long-standing racial stereotype that associates ‘Coloured’ racial identity with an enhanced susceptibility to drug use. The National Drug Master Plan (South Africa, 2012a), and the Prevention of and Treatment for Substance Abuse Act (Act no 70 of 2008) propose that drug prevention programmes should address the values, perceptions, expectations and beliefs that the community associates with drug abuse (South Africa, 2008b). This view emphasises the importance of drug preventions interventions that are culturally sensitive and contextually relevant. The current study was guided by two conceptual frameworks, i.e. the Social Constructionist Framework and the Ecological Risk/Protective Resilience Framework, and focused on the Northern Areas of Port Elizabeth, a historically marginalised community inhabited by a predominantly ‘Coloured’ indigenous/ethnic group. The goal of the study was to enhance understanding of the socio-cultural meaning attributed to cultural identity, drug use, non-use and drug prevention in the Northern Areas of Port Elizabeth, with the view to developing guidelines for drug prevention interventions that are culturally sensitive and contextually relevant. The following objectives were formulated in order to achieve the goal of the study: • To explore adolescent narratives regarding the constructs ‘Coloured’, drug use, non-use and drug prevention programmes of three distinct groups of adolescents (drug users, non-users, and TADA peer mentors) from the Northern Areas. • To explore and describe the social service practitioners’ (social workers and social auxiliary workers’) constructions of drug use, non-use and drug abuse prevention in relation to adolescents from the Northern Areas, and how such constructions inform the drug prevention services rendered to adolescents from these communities. • To review the data collected from the adolescent narratives and the social service practitioners’ reflections on their drug prevention programmes against existing theory and models for drug prevention. • To synthesise the above information with a view to developing guidelines for culturally sensitive drug prevention programmes relevant and responsive to the specific social constructions of adolescents from the Northern Areas. A qualitative research approach, located in a narrative tradition of inquiry research design, was employed to achieve the goal of the study (Riessman, 2008). The study was conducted in two phases. The first phase involved an empirical study with the four sample groups (i.e. adolescent drug users, adolescent non-drug users, Teenagers against Drug Abuse [TADA] peer mentors and social service professionals (i.e. social workers and social auxiliary workers)). Phase two involved the co-construction of the practice guidelines for culturally sensitive and contextually relevant drug prevention interventions. Phase one started with the informal exploration of community stakeholders’ views on the identified research problem and the process of gaining access to the research population. Several gatekeepers (i.e. teachers, social workers, the Families Against Drugs [FAD] Support Group representatives, a minister of religion and a community stakeholder) were engaged to assist in recruiting participants from the four sample groups. A non-probability purposive sampling method was employed to purposively recruit 29 adolescent non-drug users and ten adolescent peer mentors (via the TADA Programme at one school). The same sampling method, followed by a snowball sampling technique, was employed to recruit the two remaining sample groups of ten adolescent drug users (in the recovery process) and nine social workers and social auxiliary workers respectively. The sample sizes were determined by the principle of data saturation.The data generation method used in respect of the non-users took the form of semi-structured written narratives, administered in a group context during school time, followed by a second round of data generation. The life-grid (Wilson, Cunningham-Burley, Bancroft, Backett-Milburn & Masters, 2007:144), a qualitative visual tool for mapping important life events, was employed to guide the co-construction of the biographical narratives generated during the individual semi-structured interviews with the sample of adolescent drug users. Focus group interviews were used to enhance an understanding of the peer mentors and social service practitioners’ views on the construct ‘Coloured’ and their existing drug prevention programmes. Each of the individual and focus group interviews was audio-recorded, transcribed and complemented by the field notes. Informal data gathering occurred through participant observation of two drug prevention programmes, attendance of a FAD Support Group meeting, and interviews with community volunteers and the South African Police Services (SAPS) Youth Development Forum. Both the content and the context of the narratives were analysed to arrive at the research themes, sub-themes and categories. The content of the narratives was analysed by employing categorical content analysis, whilst the form of the narratives (i.e. how the stories were told) was analysed by using the socio-cultural approach to narrative analysis (Grbich, 2007:130). The journey metaphor emerged from the adolescent drug users’ narratives, depicting a prototypical storyline of a drug use journey, starting with experimentation and culminating in abuse and dependence for some and an early exit from the journey for others. The conclusions that can be drawn from these findings illuminate key protective factors and processes at a multisystemic level that can be strengthened to enhance the adolescents’ resistance to drug use and/or delay the onset of use. Embedded in the participants’ narration of the drug use journey were nuances relating to internalised stereotypes of ‘White’ supremacy and ‘Coloured’ inferiority as an explanatory framework for venturing onto and prolonging the journey.The two themes that emerged during the process of content and narrative analysis of the qualitative data (from both adolescent drug users and non-users) were as follows: Constructing drug use as a ‘Coloured’ phenomenon and reconstructing ‘Coloured’ identity; Risk and protective factors located at individual, family, peer, school, community and societal domains. The four themes that emerged during the data analysis of the peer mentors and social service practitioners’ narratives were as follows: Construction of ‘Coloured’ identity; socio-cultural meaning construction about the reasons for drug use amongst adolescents from the Northern Areas; description of drug prevention services rendered in the Northern Areas; and reflection on barriers to rendering drug prevention interventions

Renewing Local Planning to Face Climate Change in the Tropics

climate vulnerability; urban resilience; climate change; adaptation; planning; environmental risk analysis; decision making; disaster risk reduction; tropical climate managemen

Renewing Local Planning to Face Climate Change in the Tropics

This book aims to inspire decision makers and practitioners to change their approach to climate planning in the tropics through the application of modern technologies for characterizing local climate and tracking vulnerability and risk, and using decision-making tools. Drawing on 16 case studies conducted mainly in the Caribbean, Central America, Western and Eastern Africa, and South East Asia it is shown how successful integration of traditional and modern knowledge can enhance disaster risk reduction and adaptation to climate change in the tropics. The case studies encompass both rural and urban settings and cover different scales: rural communities, cities, and regions. In addition, the book looks to the future of planning by addressing topics of major importance, including residual risk integration in local development plans, damage insurance and the potential role of climate vulnerability reduction credits. In many regions of the tropics, climate planning is growing but has still very low quality. This book identifies the weaknesses and proposes effective solutions

Resilient Recovery: A systems analysis of disaster recovery in Canada

The frequency and severity of disasters caused by natural hazards and extreme weather is increasing across Canada. Each year, more communities face devastation, disruption, and the difficult task of rebuilding. However, the process by which communities pick up the pieces – disaster recovery – is currently failing to deliver more resilient communities. In Canada, disaster recovery prioritizes the rapid return to pre-disaster conditions without consideration for the changing risk environment and the ways in which recovery can enable communities to better prepare for the future. Our commitment to this failing system has long-term consequences. With the cost of disasters dramatically increasing, how we rebuild communities contributes to their vulnerability or resilience in the future. Because of the static nature of physical structures, with building and infrastructure lifespans of more than fifty years, recovery locks in the risk profile of a community’s built environment for generations. This project examines the barriers and opportunities for municipalities, the level of government closest to the individuals and businesses devastated by disaster, to integrate systematic disaster risk reduction into recovery and thereby rebuild more resilient communities. Using systems thinking informed by foresight and human-centered design research methods, this study aims to identify the constraints and leverage points for changing our approach to recovery in Canada so it prioritizes resilience to future risks instead of recreating the past. Resilient Recovery: A systems analysis begins by describing disaster trends in Canada and the factors increasing disaster risk, then traces of evolution of the disaster recovery system and analyzes the dynamics at play in the current system. It explores emerging forces of change and the implications these emergent issues may have for recovery, then concludes with an analysis of the system’s leverage points, considerations for how foresight could enhance the process, and a proposed pathway towards transformational change

World Water Development Report 4: Managing Water Under Uncertainty and Risk

Building on the comprehensive approach taken in World Water Development Reports (WWDRs) 1 and 2, and the holistic view taken in WWDR3, this fourth edition gives an account of the critical issues facing water's challenge areas and different regions and incorporates a deeper analysis of the external forces (i.e. drivers) linked to water. In doing so, the WWDR4 seeks to inform readers and raise awareness of the new threats arising from accelerated change and of the interconnected forces that create uncertainty and risk - ultimately emphasizing that these forces can be managed effectively and can even generate vital opportunities and benefits through innovative approaches to allocation, use and management of water

State building as strategy: An interrogation of NATO's comprehensive approach in Afghanistan between 2006 and 2011

The core of this thesis is the study of NATO’s Comprehensive Approach strategy to state building in Afghanistan between 2006 and 2011. It argues that this strategy sustained operational and tactical practices which were ineffective in responding to the evolved nature of the security problem. The thesis interrogates the Comprehensive Approach along ontological, empirical and epistemological lines and concludes that the failure of the Comprehensive Approach in the specific Afghan case is, in fact, indicative of underlying theoretical and pragmatic flaws which, therefore, generalize the dilemma. The research is pragmatic in nature, employing mixed methods (quantitative and qualitative) concurrently. Qualitative methods include research into primary and secondary literature sources supplemented with the author’s personal experiences in Afghanistan in 2008 and various NATO HQ and Canadian settings. Quantitative research includes an empirical case study focussing on NATO’s Afghan experience and its attempt at state building between 2006 and 2011. This study incorporates a historical review of NATO’s evolutionary involvement in Afghanistan incorporating the subject timeframe; offers an analysis of human development and governance related data mapped to expected outcomes of the Afghan National Development Strategy and NATO’s comprehensive campaign design; and interrogates the Comprehensive Approach strategy by means of an analysis of conceptual, institutional and capability gaps in the context of an integrated investigational framework. The results of the case study leads to an investigation of a series of research questions related to the potential impact of the failure of the Comprehensive Approach for NATO in Afghanistan and the limits of state building as a means of attaining security for the Alliance

The effect of charge location in ion mobility mass spectrometry for small molecule analytes

In travelling wave IM-MS an electric field is applied across the IMS cell and analyte collisions with the inert gas give rise to a relationship between the drift time and the molecular shape and overall charge. Recent findings show near baseline IMS separation (R>1) where shape and overall charge appear not to explain the IMS separation. Multiple ion mobility peaks are observed for a single m/z including the fluoroquinolone antibiotics norfloxacin and lomefloxacin, the pesticide indoxacarb and a number of steroids