A Continuation Method for Nash Equilibria in Structured Games

Structured game representations have recently attracted interest as models for multi-agent artificial intelligence scenarios, with rational behavior most commonly characterized by Nash equilibria. This paper presents efficient, exact algorithms for computing Nash equilibria in structured game representations, including both graphical games and multi-agent influence diagrams (MAIDs). The algorithms are derived from a continuation method for normal-form and extensive-form games due to Govindan and Wilson; they follow a trajectory through a space of perturbed games and their equilibria, exploiting game structure through fast computation of the Jacobian of the payoff function. They are theoretically guaranteed to find at least one equilibrium of the game, and may find more. Our approach provides the first efficient algorithm for computing exact equilibria in graphical games with arbitrary topology, and the first algorithm to exploit fine-grained structural properties of MAIDs. Experimental results are presented demonstrating the effectiveness of the algorithms and comparing them to predecessors. The running time of the graphical game algorithm is similar to, and often better than, the running time of previous approximate algorithms. The algorithm for MAIDs can effectively solve games that are much larger than those solvable by previous methods

Different Target Modalities Improve the Single Probe Protocol of the Response Time-Based Concealed Information Test

To detect if someone hides specific knowledge (called “probes”), the response time-based Concealed Information Test (RT-CIT) asks the examinee to classify items into two categories (targets/non-targets). Within the non-targets, slower RTs to the probes reveal recognition of concealed information. The preferred protocol examines one piece of information per test block (single probe protocol), but its validity is suboptimal. The aim of this study was to improve the validity of the single probe protocol by presenting the information in multiple modalities. In a preregistered study (N = 388) participants were instructed to try to hide their nationality. The items referring to the nationality were presented as words, flags, and maps. Increasing the number of modalities of the targets (BF10 = 37), but not of the probes and irrelevants (BF01 = 6), increased the CIT-effect.</p

Electronic Correlation in Molecular Systems: An Effective Interaction Approach

Numerous methods have been proposed which can account for the correlation between electrons. The aim of this note is to use one of them that has been used in nuclear physics with some success. The mathematical procedure is as follows: The Hamiltonian of the molecular system

Pilot Experiments with Electrodialysis and Ozonation for the Production of a Fertilizer from Urine

Pilot tests were performed with a process combination of electrodialysis and ozonation for the removal of micropollutants and the concentration of nutrients in urine. In continuous and batch experiments, maximum concentration factors up to 3.5 and 4.1 were obtained, respectively. The desalination capacity did not decrease significantly during continuous operation periods of several weeks. Membrane cleaning after 195 days resulted in approximately 35% increase in desalination rate. The Yeast Estrogen Screen (YES), a bioassay that selectively detects oestrogenic compounds, confirmed that about 90% of the oestrogenic activity was removed by electrodialysis. HPLC analysis showed that ibuprofen was removed to a high extent, while other micropollutants were below the detection limit. In view of the fact that ibuprofen is among the most rapidly transported micropollutants in electrodialysis processes, this result indicates that electrodialysis provides an effective barrier for micropollutants. Standardised plant growth tests were performed in the field with the salt solution resulting from the treatment by electrodialysis and subsequent ozonation. The results show that the plant height is comparable to synthetic fertilisers, but the crop yield is slightly lower. The latter is probably caused by volatilisation losses during field application, which can be prevented by improved application technologies