From Competition to Complementarity: Comparative Influence Diffusion and Maximization

Influence maximization is a well-studied problem that asks for a small set of influential users from a social network, such that by targeting them as early adopters, the expected total adoption through influence cascades over the network is maximized. However, almost all prior work focuses on cascades of a single propagating entity or purely-competitive entities. In this work, we propose the Comparative Independent Cascade (Com-IC) model that covers the full spectrum of entity interactions from competition to complementarity. In Com-IC, users' adoption decisions depend not only on edge-level information propagation, but also on a node-level automaton whose behavior is governed by a set of model parameters, enabling our model to capture not only competition, but also complementarity, to any possible degree. We study two natural optimization problems, Self Influence Maximization and Complementary Influence Maximization, in a novel setting with complementary entities. Both problems are NP-hard, and we devise efficient and effective approximation algorithms via non-trivial techniques based on reverse-reachable sets and a novel "sandwich approximation". The applicability of both techniques extends beyond our model and problems. Our experiments show that the proposed algorithms consistently outperform intuitive baselines in four real-world social networks, often by a significant margin. In addition, we learn model parameters from real user action logs.Comment: An abridged of this work is to appear in the Proceedings of VLDB Endowment (PVDLB), Vol 9, No 2. Also, the paper will be presented in the VLDB 2016 conference in New Delhi, India. This update contains new theoretical and experimental results, and the paper is now in single-column format (44 pages

Does poverty cause conflict? Isolating the causal origins of the conflict trap

Does poverty cause civil conflict? A considerable literature seeks to answer this question, yet concerns about reverse causality threaten the validity of extant conclusions. To estimate the impact of poverty on conflict and to determine whether the relationship between them is causal, it is necessary to identify a source of exogenous variation in poverty. We do this by introducing a robust instrument for poverty: a time-varying measure of international inequalities. We draw upon existing theories about the structural position of a country in the international economic network—specifically, the expectation that countries in the core tend to be wealthier and those on the periphery struggle to develop. This instrument is plausibly exogenous and satisfies the exclusion restriction, which suggests that it affects conflict only through its influence upon poverty. Instrumental variables probit regression is employed to demonstrate that the impact of poverty upon conflict appears to be causal

Disentangling causal webs in the brain using functional Magnetic Resonance Imaging: A review of current approaches

In the past two decades, functional Magnetic Resonance Imaging has been used to relate neuronal network activity to cognitive processing and behaviour. Recently this approach has been augmented by algorithms that allow us to infer causal links between component populations of neuronal networks. Multiple inference procedures have been proposed to approach this research question but so far, each method has limitations when it comes to establishing whole-brain connectivity patterns. In this work, we discuss eight ways to infer causality in fMRI research: Bayesian Nets, Dynamical Causal Modelling, Granger Causality, Likelihood Ratios, LiNGAM, Patel's Tau, Structural Equation Modelling, and Transfer Entropy. We finish with formulating some recommendations for the future directions in this area

Economic Concepts of Organic Certification

Certification is a key element in marketing organic food products. Based on economic theory, this report wants to illustrate the economic reasoning for certification. The intention is to provide a description of economic concepts, which is understandable for a wider audience. We are focusing on the basic economic literature. Chapter 1 “Organic certification system” describes the current control system in the European Union. Why this is necessary, will then be explained based on a synopsis of economic literature. Of specific significance for organic certification and the CERTCOST project are the concepts of institutional economics and economics of crime. The relevant points of economic theory will be presented and discussed in chapter 2 “Theoretical framework”. Finally, the costs and benefits of organic certification will be illustrated in chapter 3 “Costs and benefits of organic certification”

European consumers' interest in nutrition information on (sugar-free) chewing gum

Much consumer and public health research into nutrition labelling has explored the effects of information provision on consumer behaviour and how it can help consumers in making informed food choices. Among other things, it has been shown that European consumers' interest in and use of nutrition information varies greatly across country and product category. Chewing gum represents an understudied product category where little is known about whether consumers are interested in and would use nutrition information, let alone where they might want to access it due to small pack sizes limiting the space available to provide the information. The present study investigates European consumers (n = 3500) in seven countries and shows that while overall interest in nutrition information on chewing gum is relatively low, considerable differences can be observed with regards to users of regular versus sugar-free chewing gum, as well as with regards to low/medium versus heavy users. Sugar-free chewing gum users are more interested in general as well as specific nutrition information that is relevant for chewing gum, compared to regular chewing gum users. And low and medium user groups have a better awareness of which nutrients are relevant for chewing gum, compared to heavy users who appear less concerned about nutrition and health. The results provide insights into European consumers' attitudes towards nutrition information for chewing gum, and alternative sources of such information provision as pack size is a limiting factor in regards to this product

Prison health in NHS Greater Glasgow & Clyde : A health needs assessment 2012

Scotland has one of the highest rates of imprisonment in Western Europe and the prison population is rising [1]. In the last decade the average daily prison population in Scotland increased by 27% [1]. The burden of physical and mental illness in the prison population is high; disproportionately so when compared to the general population [2]. This has variably been attributed to socioeconomic disadvantage and lifestyle and behavioural factors such as substance misuse, smoking and poor nutrition which are common in the prison population [2,3]. Prisoners suffer from multiple deprivation [2,3]. Many are a product of the care system, have experienced physical, emotional or sexual abuse and have difficulties forming and maintaining relationships. Levels of educational attainment are low and unemployment high. Homelessness is common. Prior to incarceration prisoners rarely engage with health care services in the community; during imprisonment demand for health care services is high [3,6,7]. Traditionally health care services in Scottish prisons were provided by the Scottish Prisons Service (SPS). On 1st November 2011 responsibility for the provision of health care to prisoners was transferred from SPS to the National Health Service (NHS). The aim of the transfer was to ensure that prisoners received the same standard of care and range of services as offered to the general population according to need. The guiding principle is that of ‘equivalence’ of care. The aim of this Health Needs Assessment (HNA) was to provide a systematic baseline assessment of the health and health care needs of prisoners in NHS Greater Glasgow and Clyde (NHSGGC) and to identify gaps in the current service provision to inform service future planning and development. It focuses on the two operational publicly owned prisons within NHSGGC: HMP Barlinnie and HMP Greenock. A third prison, HMP Low Moss, falls under the remit of NHSGGC but it was under renovation at the time of this HNA. Information about the prison population was drawn from published literature and reports provided by staff from the Justice and Communities Directorate of the Scottish Government. Information about the prisons from HMP Inspectorate reports, direct observation and interviews with members of staff in each prison. To fully understand the level and nature of existing services a service mapping was undertaken jointly with nominated staff from the prison health teams using direct observation and extensive staff and prisoner interviews and focus groups. Overall the findings are in line with other national and international studies on prison health. Despite characteristic differences between the prisons within NHSGGC there was a high level of consensus amongst both prisoners and staff groups about health needs and priorities. The report acknowledges the thoughtful contribution of prison staff and the positive approach to improving health services that they expressed. This has impacted on the formation of recommendations that both validate existing approaches and identify opportunities and 10 priorities for health gain. In addition to more fundamental changes they identify opportunities for quick wins that do not require significant financial outlay

Entering the blackboard jungle: canonical dysfunction in conscious machines

The central paradigm of Artificial Intelligence is rapidly shifting toward biological models for both robotic devices and systems performing such critical tasks as network management and process control. Here we apply recent mathematical analysis of the necessary conditions for consciousness in humans in an attempt to gain some understanding of the likely canonical failure modes inherent to a broad class of global workspace/blackboard machines designed to emulate biological functions. Similar problems are likely to confront other possible architectures, although their mathematical description may be far less straightforward