Optimal information diffusion in stochastic block models

We use the linear threshold model to study the diffusion of information on a network generated by the stochastic block model. We focus our analysis on a two community structure where the initial set of informed nodes lies only in one of the two communities and we look for optimal network structures, i.e. those maximizing the asymptotic extent of the diffusion. We find that, constraining the mean degree and the fraction of initially informed nodes, the optimal structure can be assortative (modular), core-periphery, or even disassortative. We then look for minimal cost structures, i.e. those such that a minimal fraction of initially informed nodes is needed to trigger a global cascade. We find that the optimal networks are assortative but with a structure very close to a core-periphery graph, i.e. a very dense community linked to a much more sparsely connected periphery.Comment: 11 pages, 6 figure

Alien Registration- Curato, Joseph (Rumford, Oxford County)

https://digitalmaine.com/alien_docs/13637/thumbnail.jp

Respondents as Interlocutors: Translating Deliberative Democratic Principles to Qualitative Interviewing Ethics

The epistemic interview is a conversational practice, which aims to generate knowledge by subjecting respondents’ beliefs to dialectical tests of reasons. Developed by Svend Brinkmann, this model draws inspiration from Socratic dialogues where the interviewer asks confronting questions to press respondents to articulate the normative bases of their views. In this article, the author argues that Brinkmann’s model is a valuable methodological innovation but warrants further development. The author suggests that the epistemic interview can be put on a stronger methodological footing when the Socratic model is complemented by developments in democratic theory, particularly its deliberative variety. Translating deliberative democratic virtues to methodological terms addresses some of the epistemic model’s gaps, including an account of the dynamic of knowledge production and the ethical norms that govern this method. To illustrate the practice of epistemic interviewing, the author draws on her experience in interviewing junior military officer

‘We haven’t even buried the dead yet’:Ethics of discursive contestation in a crisis situation

Disasters are often described as exceptional moments that demand global solidarity. A ‘state of humanitarian exception’ emerges as citizens foreground norms of compassion and cooperation while contestatory discourse – the argumentative, blame-seeking and fault-finding forms of speech – are stigmatized as inappropriate interventions in a society seeking to recover from a distressful crisis situation. This article critically unpacks these representations of post-disaster situations empirically and normatively. By analysing the discussions in the public sphere over the first 100 days after Typhoon Haiyan battered Central Philippines, the article examines the moral force behind the ‘discourse of compassion’ and its ‘ethical boundary work’ that places the ‘discourse of contestation’ outside the scope of acceptable conduct. It proposes that the discourse of compassion’s ethical boundary work is only democratically acceptable when one takes a short view of a crisis situation. Drawing on deliberative democracy theory, the article argues for the importance of contestatory discourse in fostering inclusive discourse formation and ensuring that the state of humanitarian exception does not become the rule.</jats:p

Nonlinearity in high-frequency finance and optimal execution

In this thesis we consider two problems regarding the eld of market microstructure: the analysis and modeling of high frequency nancial data and the optimal execution of large orders. The rst problem is analyzed empirically within the context of the dynamics of limit order books. Such context imposes a discrete modeling approach about the variables of interest, like prices and bid-ask spreads. The optimal execution problem, instead, is analyzed within the context of a price model which allows for a nonlinear-transient market impact [43, 104]. Our interest is motivated by the fact that the study and implementation of optimal strategies is one of the main tasks of large banks and capital investment rms. The two problems are de ned by two di erent nonlinear models. A nonlinear modeling approach is necessary in order to reproduce the empirical data. Our work focuses on the analysis of the implications of such nonlinearities on the stochastic dynamics of prices and on optimal strategies. [...