An automatic robust Bayesian approach to principal component regression

Principal component regression uses principal components (PCs) as regressors. It is particularly useful in prediction settings with high-dimensional covariates. The existing literature treating of Bayesian approaches is relatively sparse. We introduce a Bayesian approach that is robust to outliers in both the dependent variable and the covariates. Outliers can be thought of as observations that are not in line with the general trend. The proposed approach automatically penalises these observations so that their impact on the posterior gradually vanishes as they move further and further away from the general trend, corresponding to a concept in Bayesian statistics called whole robustness. The predictions produced are thus consistent with the bulk of the data. The approach also exploits the geometry of PCs to efficiently identify those that are significant. Individual predictions obtained from the resulting models are consolidated according to model-averaging mechanisms to account for model uncertainty. The approach is evaluated on real data and compared to its nonrobust Bayesian counterpart, the traditional frequentist approach and a commonly employed robust frequentist method. Detailed guidelines to automate the entire statistical procedure are provided. All required code is made available, see ArXiv:1711.06341.     

New public management and professionals in the public sector. What new patterns beyond opposition?

The proliferation of reforms in public administration based on the principles and instruments of the “New Public Management” (NPM) have triggered protest from and collective action by many professional groups in various sectors (healthcare, education, justice, social work, research…) and raised questions about the future of professionals working in the public service, particularly as concerns their autonomy. However, after analyzing the situation, it seems that the opposition between NPM and certain professional groups is not the last word in the debate. Should changes be seen as the decline of professional groups and of their autonomy or as a transformation of professional models, an overhaul of professionalism, etc.? Such questions, which current events in France and Europe have brought to the fore, are food for ongoing sociological thought. They are broached here empirically, from the field, applying varied levels of analysis and research. The contributors to this dossier explore the different forms of tension existing between professional groups and NPM.     

Two-step values for games with two-level communication structure

TU games with two-level communication structure, in which a two-level communication structure relates fundamentally to the given coalition structure and consists of a communication graph on the collection of the a priori unions in the coalition structure, as well as a collection of communication graphs within each union, are considered. For such games we introduce two families of two-step values inspired by the two-step procedures staying behind the Owen value (Owen, in: Henn, Moeschlin (eds) Essays in mathematical economics and game theory, Springer, Berlin, pp 76–88, 1977) and the two-step Shapley value (Kamijo in Int Game Theory Rev 11:207–214, 2009) for games with coalition structure. Our approach is based on the unified treatment of several component efficient values for games with communication structure and it generates two-stage solution concepts that apply component efficient values for games with communication structure on both distribution levels. Comparable axiomatic characterizations are provided.     

Coalitional desirability and the equal division value

Theory and Decision - We introduce three natural collective variants of the well-known axiom of desirability (Maschler and Peleg in Pac J Math 18:289–328, 1966), which require that if the...     

The Coalitional Nash Bargaining Solution

The coalitional Nash bargaining solution is defined to be the core allocation for which the product of players' payoffs is maximal. We consider a non‐cooperative model with discounting in which one team may form and every player is randomly selected to make a proposal in every period. The grand team, consisting of all players, generates the largest surplus. But a smaller team may form. We show that as players get more patient if an efficient and stationary equilibrium exists, it must deliver payoffs that correspond to the coalitional Nash bargaining solution. We also characterize when an efficient and stationary equilibrium exists, which requires conditions that go beyond the nonemptiness of the core.     

Using heuristics to find minimal unsatisfiable subformulas in satisfiability problems

In this paper, we propose efficient algorithms to extract minimal unsatisfiable subsets of clauses or variables in unsatisfiable propositional formulas. Such subsets yield unsatisfiable propositional subformulas that become satisfiable when any of their clauses or variables is removed. These subformulas have numerous applications, including proving unsatisfiability and post-infeasibility analysis. The algorithms we propose are based on heuristics, and thus, can be applied to large instances. Furthermore, we show that, in some cases, the minimality of the subformulas can be proven with these algorithms. We also present an original algorithm to find minimum cardinality unsatisfiable subformulas in smaller instances. Finally, we report computational experiments on unsatisfiable instances from various sources, that demonstrate the effectiveness of our algorithms.     

Interaction Patterns in Adolescent Romantic Relationships: A Typological Analysis

While several studies in adolescents have addressed issues related to romantic relationships and dating violence, there is a limited understanding of their interaction patterns. This study aims to document interactions in conflict situations by identifying profiles of adolescent romantic relationships. Qualitative analysis based on the dimensions of the Circumplex Model of Marital and Family Systems was used to investigate the interaction task of 40 dyads. A typological analysis revealed four profiles: (1) rigid, (2) entangled, (3) hampered, and (4) balanced. Results highlight the diversity of romantic experiences and offer a better understanding of the intricacies of different interaction profiles. Dating violence prevention efforts and programs promoting harmonious and egalitarian romantic relationships could benefit from the insights of the identified profiles.