Opinion formation models based on game theory

A way to simulate the basic interactions between two individuals with different opinions, in the context of strategic game theory, is proposed. Various games are considered, which produce different kinds of opinion formation dynamics. First, by assuming that all individuals (players) are equals, we obtain the bounded confidence model of continuous opinion dynamics proposed by Deffuant et al. In such a model a tolerance threshold is defined, such that individuals with difference in opinion larger than the threshold can not interact. Then, we consider that the individuals have different inclinations to change opinion and different abilities in convincing the others. In this way, we obtain the so-called ``Stubborn individuals and Orators'' (SO) model, a generalization of the Deffuant et al. model, in which the threshold tolerance is different for every couple of individuals. We explore, by numerical simulations, the dynamics of the SO model, and we propose further generalizations that can be implemented.Comment: 18 pages, 4 figure

The effect of organic management on soil quality indicators

This report was presented at the UK Organic Research 2002 Conference. A range of physical, biological and chemical parameters were measured in organic soil that had been managed in different ways and in a conventional control. Factors were identified that could be used to construct an index of soil quality

Analysis of the commutation error of filtering operators for the double-averaged equations of flows in porous media in a LES formalism

The continuum approach employing porous media models is an attractive solution method in the area of Computational Fluid Dynamics (CFD) simulation of fixed-bed reactors due to its robustness and efficiency. This paper applies the double-averaging methodology to refine the mathematical basis for the continuum approach, opening a way to alleviate its main limitations: space-invariant averaging volume and inaccurate treatment of the porous/non-porous interface. The averaging operator is recast as a general space-time filter and a detailed analysis of commutation errors is performed, using a classic Large Eddy Simulation (LES) formalism. An explicit filtering framework has been implemented in the open-source CFD library OpenFOAM to carry out an a-posteriori evaluation of the unclosed terms appearing in the Double-Averaged Navier-Stokes (DANS) equations also considering a space-varying filter width. Two resolved simulations have been performed. First, the flow around a single, stationary particle has been considered and used to validate derived equations and the filtering procedure. Second, an LES of the turbulent flow in a channel partly occupied with a porous medium has been conducted. The results have been filtered, and the commutation error at the porous-fluid interface has been evaluated and compared to the prediction of two models. The significance of the commutation error terms is also discussed and assessed. Finally, the solver for DANS equations has been developed and used to simulate both of the studied geometries. The magnitude of the error associated with neglecting the commutation errors has been investigated and an LES simulation combined with a porous drag model was performed. Very encouraging results have been obtained indicating that the inaccuracy of the drag closure overshadows the error related to the commutation of operators.Comment: This material has been submitted to Physics of Fluids. It contains 33 pages and 21 Figure

Homotopy Theory of Strong and Weak Topological Insulators

We use homotopy theory to extend the notion of strong and weak topological insulators to the non-stable regime (low numbers of occupied/empty energy bands). We show that for strong topological insulators in d spatial dimensions to be "truly d-dimensional", i.e. not realizable by stacking lower-dimensional insulators, a more restrictive definition of "strong" is required. However, this does not exclude weak topological insulators from being "truly d-dimensional", which we demonstrate by an example. Additionally, we prove some useful technical results, including the homotopy theoretic derivation of the factorization of invariants over the torus into invariants over spheres in the stable regime, as well as the rigorous justification of replacing $T^d$ by $S^d$ and $T^{d_k}\times S^{d_x}$ by $S^{d_k+d_x}$ as is common in the current literature.Comment: 11 pages, 3 figure

From Goya to Afghanistan. An essay on the ratio and ethics of medical war pictures

For centuries pictures of the dead and wounded have been part and parcel of war communications. Often the intentions were clear, ranging from medical instructions to anti-war protests. The public's response could coincide with or diverge from the publisher's intention. Following the invention of photography in the nineteenth century, and the subsequent claim of realism, the veracity of medical war images became more complex. Analysing and understanding such photographs have become an ethical obligation with democratic implications. We performed a multidisciplinary analysis of War Surgery (2008), a book containing harsh, full-colour photographs of mutilated soldiers from the Iraq and Afghanistan wars. Our analysis shows that, within the medical context, this book is a major step forward in medical war communication and documentation. In the military context the book can be conceived as an attempt to put matters right given the enormous sacrifice some individuals have suffered. For the public, the relationship between the 'reality' and 'truth' of such photographs is ambiguous, because only looking at the photographs without reading the medical context is limiting. If the observer is not familiar with medical practice, it is difficult for him to fully assess, signify and acknowledge the value and relevance of this book. We therefore assert the importance of the role of professionals and those in the humanities in particular in educating the public and initiating debate. © 2010 Taylor & Francis

Determinants of birth asphyxia among preterm newborns in Ethiopia : a systematic review and meta-analysis of observational studies protocol

Background: Birth asphyxia accounted for nearly 50% of neonatal mortality in Sub-Saharan African countries. This scenario has been worst in Ethiopia where every two out of three deaths attributed to birth asphyxia. Moreover, studies conducted in Ethiopia were highly variable and inconclusive to estimate the pooled prevalence and determinants of perinatal birth asphyxia among preterm babies. Objective: This study aimed to estimate the pooled prevalence of birth asphyxia and its determinants among preterm newborns in Ethiopia. Methods: The protocol for this review is registered at PROSPERO with registration number CRD42020158224. A comprehensive online databases (PubMed, HINARI, Scopus, EMBASE, Science direct, and Cochrane library database), Google Scholar, African Journals online, other gray and online repository accessed studies will be searched using different search engines. In addition, maternity and infant care databases uploaded at Ethiopian Health Development Journal and Ethiopian Journal of Health Sciences will be searched until 30 June 2020. Newcastle-Ottawa Quality Assessment Scale (NOS) will be used for critical appraisal of studies. Three reviewers will screen all retrieved articles, conduct data extraction, and then critically appraise all identified studies. All identified observational studies reporting the prevalence of birth asphyxia and associated factors among neonates in Ethiopia will be considered. The analysis of data will be done using STATA 11.0. We will demonstrate pooled estimates and determinants of birth asphyxia with effect size and 95% confidence interval. Heterogeneity among the included studies will be assessed through the Cochrane Q test statistics and I2 test. Publication bias will be checked using funnel plot and Egger’s test. Finally, statistical significance level will be declared at a p value of less than 0.05. Discussion: The result from this systematic review will inform and guide health policy planners to invest limited resources on maternal and neonatal health. Furthermore, it will be a stimulus for future cumulative meta-analysis researchers in developing nations

Sistem Pendeteksian Penyusupan Jaringan Komputer dengan Active Response Menggunakan Metode Hybrid Intrusion Detection, Signatures dan Anomaly Detection

The progress of internet technology increase the need of security data. The progress of tools which have intrusion ability, also influence these needed. The methods of Intrusion Detection System (IDS) implementation and methods of analyze intrusion have excess and lack, which mutually completes. There are a lot of IDS now, but just an IDS open source based is snort. Method of snort implementation is network based restricted. This Final Task's system used Hybrid Intrusion Detection System, Signatures and Anomaly Detection Methods. The indicator which used to detect intrusion are IP Address and Port Number. This system use TCP, UDP and ICMP protocols. This system also, is completed by active response, like blocking access for intruder. This System Implementation with Java Programming Language for engine perform and Java Server Pages (JSP) to develop user interface, The database which used is MYSQL. There are two of development test; Link system test and intrusion test. The link system test show the connect each interface. Intrusion is executed by host detection which used DoS HTTP tools and network detection which used Ping of Death's scripts. The intrusion testing conclusions are; can be detected, analyze and active response for intrusion

A multi-model approach to stakeholder engagement in complex environmental problems

We describe the different types of models we used as part of an effort to inform policy-making aiming at the management of the Ningaloo coast in the Gascoyne region, Western Australia. This provides an overview of how these models interact, the different roles they cover, how they fit into a full decision making process and what we learnt about the stakeholders involved in our project via their use. When modelling is explicitly used to address socio-ecological issues, the key determinant of success is whether the models, their results and recommendations are taken up by stakeholders; such uptake in turn depends on addressing stakeholders’ concerns, on engaging them in the project, on ensuring they feel ownership of the decision process at large, and that they understand and trust the modelling effort. This observation has guided our approach and has resulted in treating ‘building a model’ as the catalyst, rather than the final aim, of the process. In other words, extensive interactions in order to introduce, showcase, discuss and tune the model used for final decision making have represented both a requirement and an opportunity to ensure (i) model relevance, (ii) its acceptance, (iii) that all information available in the stakeholder team was accounted for and (iv) that stakeholders holding different levels of understanding of modelling, what it does and what it can provide to decision-making could develop an informed opinion on its use. To fulfil these roles we developed five broad classes of models: conceptual models, toy-models, singlesystem models, shuttle-models and a full-system model. In conceptual models the main drivers of a system are highlighted for subsequent representation as components of the full-system model. This usually results in a diagram summarising our understanding of how the system works. In toy-models a problem is simplified in such a way that only a handful of components are included. The purpose of these models is mostly educational: we want to understand how each component affects the problem and in order to achieve this, we temporarily renounce a satisfactory understanding of the overall problem. In single-system models we include a fairly detailed representation of a single component of the system (in our case recreational fishing and tourism); these models can be used to introduce stakeholders to modelling, provide temporary results from the study of a single activity, which will feed into the development of the final full-system model, or address sector-specific issues. In shuttle-models, we include the minimum number of processes we believe are crucial for a basic understanding of the overall problem. We know these models are still too simple for full system description, but they provide a sufficient understanding to enable us to contemplate, build and use the more complex models needed for full problem description. The term ‘shuttle’ refers to taking us from a minimum to a full description of the problem, a journey which is necessary both to developers in model definition and parameterisation and to stakeholders in the interpretation of the final full-system model results. Finally, the full-system model includes all information collected through the project and addresses all scenarios of stakeholders concern, and whose definition has been greatly eased by use of the ‘simpler’ models. As an example, a conceptual model may identify fishing and tourism as the main drivers of a region; a toymodel may describe how catches affect fish stocks; a single-system model may include the effect of gear, regulations and other processes affecting recreational fishing; a shuttle-model may include a simplified representation of the interaction between fishing, tourism, and infrastructure development on the overall health of the local ecosystem; this will gradually ‘take’ us to comprehend the ‘full’ model which may include tourism pressure, fish market values, climate effect, larger food-webs, etc

Encoding simplicial quantum geometry in group field theories

We show that a new symmetry requirement on the GFT field, in the context of an extended GFT formalism, involving both Lie algebra and group elements, leads, in 3d, to Feynman amplitudes with a simplicial path integral form based on the Regge action, to a proper relation between the discrete connection and the triad vectors appearing in it, and to a much more satisfactory and transparent encoding of simplicial geometry already at the level of the GFT action.Comment: 15 pages, 2 figures, RevTeX, references adde