Computational Controversy

Climate change, vaccination, abortion, Trump: Many topics are surrounded by fierce controversies. The nature of such heated debates and their elements have been studied extensively in the social science literature. More recently, various computational approaches to controversy analysis have appeared, using new data sources such as Wikipedia, which help us now better understand these phenomena. However, compared to what social sciences have discovered about such debates, the existing computational approaches mostly focus on just a few of the many important aspects around the concept of controversies. In order to link the two strands, we provide and evaluate here a controversy model that is both, rooted in the findings of the social science literature and at the same time strongly linked to computational methods. We show how this model can lead to computational controversy analytics that have full coverage over all the crucial aspects that make up a controversy.Comment: In Proceedings of the 9th International Conference on Social Informatics (SocInfo) 201

Investigating the efficacy of bisphosphonates treatment against multiple myeloma induced bone disease using a computational model

Multiple myeloma (MM)-induced bone disease is mortal for most MM patients. Bisphosphonates are first-line treatment for MM-induced bone disease, since it can inhibit osteoclast activity and the resultant bone resorption by suppressing the differentiation of osteoclast precursors into mature osteoclasts, promoting osteoclast apoptosis and disrupting osteoclast function. However, it is still unclear whether bisphosphonates have an anti-tumour effect. In our previous work, a computational model was built to simulate the pathology of MM-induced bone disease. This paper extends this proposed computational model to investigate the efficacy of bisphosphonates treatment and then clear the controversy of this therapy. The extended model is validated through the good agreement between simulation results and experimental data. The simulation results suggest that bisphosphonates indeed have an anti-tumour effect

Correlation effects in total energy of transition metals and related properties

We present an accurate implementation of total energy calculations into the local density approximation plus dynamical mean-field theory (LDA+DMFT) method. The electronic structure problem is solved through the full potential linear Muffin-Tin Orbital (FP-LMTO) and Korringa-Kohn-Rostoker (FP-KKR) methods with a perturbative solver for the effective impurity suitable for moderately correlated systems. We have tested the method in detail for the case of Ni and investigated the sensitivity of the results to the computational scheme and to the complete self-consistency. It is demonstrated that the LDA+DMFT method can resolve a long-standing controversy between the LDA/GGA density functional approach and experiment for equilibrium lattice constant and bulk modulus of Mn.Comment: 14 pages, 5 figure

Convergence in the Finite Cournot Oligopoly with Social and Individual Learning

Convergence to the Nash equilibrium in a Cournot oligopoly is a question that recurrently arises as a subject of controversy in economics. The development of evolutionary game theory has provided an equilibrium concept more directly connected with adjustment dynamics, and the evolutionary stability of the equilibria of the Cournot game has been extensively studied in the literature. Several articles show that the Walrasian equilibrium is the stable ESS of the Cournot game. But no general result has been established for the difficult case of simultaneous heterogenous mutations.Authors propose specific selection dynamics to analyze this case. Vriend (2000) proposes using a genetic algorithm for studying learning dynamics in this game and obtains convergence to Cournot equilibrium with individual learning. The resulting convergence has been questioned by Arifovic and Maschek (2006). The aim of this article is to clarify this controversy: it analyzes the mechanisms that are behind these contradictory results and underlines the specific role of the spite effect. We show why social learning gives rise to the Walrasian equilibrium and why, in a general setup, individual learning can effectively yield convergence to the Cournot equilibrium. We also illustrate these general results by systematic computational experiments.Cournot oligopoly; Learning; Evolution; Selection; Evolutionary stability; Nash equilibrium; Genetic algorithms