Abstract. End-users studying impacts and risks caused by human-induced climate change are often presented with large multi-model ensembles of climate projections whose composition and size are arbitrarily determined. An efficient and versatile method that finds a subset which maintains certain key properties from the full ensemble is needed, but very little work has been done in this area. Therefore, users typically make their own somewhat subjective subset choices and commonly use the equally-weighted model mean as a best estimate. However, different climate model simulations cannot necessarily be regarded 5 as independent estimates due to the presence of duplicated code and shared development history.Here, we present an efficient and flexible tool that makes better use of the ensemble as a whole by finding a subset with improved mean performance compared to the multi-model mean while at the same time maintaining the spread and addressing the problem of model interdependence. Out-of-sample skill and reliability are demonstrated using model-as-truth experiments.This approach is illustrated with one set of optimisation criteria but we also highlight the flexibility of cost functions, depend-10 ing on the focus of different users. The technique is useful for a range of applications that, for example, minimise present day bias to obtain an accurate ensemble mean, reduce dependence in ensemble spread, maximise future spread, ensure good performance of individual models in an ensemble, reduce the ensemble size while maintaining important ensemble characteristics, or optimize several of these at the same time. As in any calibration exercise, the final ensemble is sensitive to the metric, observational product and pre-processing steps used.

No abstract

This report provides a comprehensive complexity study of line switching in the Linear DC model for the feasibility problem and the optimization problems of maximizing the load that can served (maximum switching flow, MSF) and minimizing generation cost (optimal transmission switching, OTS). Our results show that these problems are NP-complete and that there is no fully polynomial-time approximation scheme for planar networks with a maximum-node degree of 3. Additionally, we demonstrate that the problems are still NP-hard if we restrict the network structure to cacti with a maximum degree of 3. We also show that the optimization problems can not be approximated within any constant factor.

No abstract

The article sketches the overall layout of the thematic issue of the ‘Journal of Religion and Transformation in Contemporary Societies (JRAT)’ on Interreligious Dialogue (IRD) in context. It argues that an analysis of Interreligious Dialogue-activities in their socio-cultural contexts helps to counterbalance the long-standing individualistic bias of IRD-research. First, it presents a systematic description of the present state of the art that distinguishes two strands of IRD-research. Second, it argues for a European comparison, based upon the most recent findings from the ‘SMRE – Swiss Metadatabase of Religious Affiliation in Europe’. The article closes with references to the structure of the present volume of JRaT to facilitate such a comparison.