Prosocial dynamics in multiagent systems

Meeting today's major scientific and societal challenges requires understanding dynamics of prosociality in complex adaptive systems. Artificial intelligence (AI) is intimately connected with these challenges, both as an application domain and as a source of new computational techniques: On the one hand, AI suggests new algorithmic recommendations and interaction paradigms, offering novel possibilities to engineer cooperation and alleviate conflict in multiagent (hybrid) systems; on the other hand, new learning algorithms provide improved techniques to simulate sophisticated agents and increasingly realistic environments. In various settings, prosocial actions are socially desirable yet individually costly, thereby introducing a social dilemma of cooperation. How can AI enable cooperation in such domains? How to understand long-term dynamics in adaptive populations subject to such cooperation dilemmas? How to design cooperation incentives in multiagent learning systems? These are questions that I have been exploring and that I discussed during the New Faculty Highlights program at AAAI 2023. This paper summarizes and extends that talk

Kinetics and Mechanism of Hydrolysis of Benzimidazolylcarbamates

Synthesis of new 2-aminobenzimidazole-1-carbamates was accomplished by carbamoylation of 2-aminobenzimidazole using different substituted phenyl chloroformates. The aqueous hydrolysis of the new compounds was examined in the pH range 1-13 at 25 oC. The evaluated kinetic parameters led to the conclusion that up to pH 4 reaction proceeds by a bimolecular attack of water to the N-protonated substrate. This is the first time this behavior is described for carbamates, and can be ascribed to the higher basicity of the benzimidazolyl moiety when compared with the carbonyl oxygen. For higher values of pH, the results are consistent with a BAc2 mechanism with nucleophilic catalysis, but while between pH 4 and pH 7 water acts as the nucleophile, for pH> 7 the hydroxide ion is the acting species

Moderate Responder Committees Maximize Fairness in (NxM)-Person Ultimatum Games

We introduce and study a multiplayer version of the classical Ultimatum Game in which a group of N Proposers jointly offers a division of resources to a group of M Responders. In general, the proposal is rejected if the (average) proposed offer is lower than the (average) response threshold in the Responders group. A motivation for our work is the exchange of flexibilities between different smart energy communities, where the surplus of one community can be offered to meet the demand of a second community. We find that, in the absence of any mechanism, the co-evolving populations of Proposers and Responders converge to a state in which proposals and acceptance thresholds are low, as predicted by the rational choice theory. This is more evident if the Proposers' groups are larger (i.e., large N). Low proposals imply an unfair exchange that highly favors the Proposers. To circumvent this drawback, we test different committee selection rules which determine how Responders should be selected to form decision-making groups, contingent on their declared acceptance thresholds. We find that selecting the lowest-demanding Responders maintains unfairness. However, less trivially, selecting the highest-demanding individuals also fails to resolve this imbalance and yields a worse outcome for all due to a high fraction of rejected proposals. Selecting moderate Responders optimizes overall fitness

Adaptations to infer fitness interdependence promote the evolution of cooperation

The evolution of cooperation is a major question in the biological and behavioral sciences. While most theoretical studies model cooperation in the context of an isolated interaction (e.g., a Prisoner’s Dilemma), humans live in heterogeneous social environments, characterized by large variations in fitness interdependence—the extent to which one’s fitness is affected by others. Theoretical and experimental work indicates that humans can infer, and respond to, variations in interdependence. In a heterogeneous ancestral environment, these psychological mechanisms to infer fitness interdependence could have provided a selective advantage, allowing individuals to maximize their fitness by deciding when and with whom to cooperate. Yet, to date, the link between cognitive inference, variation in fitness interdependence, and cooperation remains unclear. Here we introduce a theoretical framework to study the evolution of inference and cooperation in heterogeneous social environments, where individuals experience interactions with varying levels of corresponding interests. Using a combination of evolutionary game theory and agent-based modeling, we model the evolution of adaptive agents, who incur a cost to infer interdependence, in populations of fixed-behavior agents who always cooperate or defect. Our results indicate that natural selection could promote the evolution of psychological mechanisms to infer fitness interdependence, provided that there is enough variation in fitness interdependence to offset the cost of inference. Under certain conditions, the fixation of adaptive agents results in higher levels of cooperation. This depends crucially on the type of inference performed and the features of the interdependence landscape

Coccinellídeos associados ao olival da Beira Interior

Com o objectivo de obter informação sobre as espécies de coccinelídeos associadas ao olival da Beira Interior, em 2003 e 2004 efectuaram-se amostragens em dois olivais considerados 401 representativos das condições da região. As amostragens decorreram entre Maio e Outubro de cada um dos anos, a uma periodicidade aproximadamente quinzenal, tendo consistido no batimento de dois ramos por árvore em cada uma de 25 árvores seleccionadas ao acaso por olival e data. A quase totalidade das capturas (96,3% em 2003 e 93,2% em 2004), obteve-se entre o início de Julho e o início de Outubro, quando se interromperam as amostragens. Os exemplares capturados identificaram-se como pertencendo a I 5 espécies, isto é: Chilocorus bipustulotus L, Exochomus nigromoculotus (Gze.), Exochomus quodripustulotus L, Plotynaspis luteorubro Gze., Stethorus punctillum Ws.), Scymnus (Scymnus) abietis (Paykull.), Scymnus (Scymnus) apetzi Muls., Scymnus (Scymnus) interruptus Gze., Scymnus (Pu/Jus) mediterraneus Khnz., Scymnus (Pullus) subvillosus Gze., Nephus (Bipunaotus) bisignotus Boheman, Coccinello septempunaoto (L.), Propyloea quotuordecimpuntocto (L), Rhyzabius laphontae (Biaisd.) e Rhyzobius litura Fabr. A espécie capturada em maior número, em qualquer dos olivais e anos de estudo, foi S. interruptus, que representou 61,3% do total de exemplares obtidos

Numerical study of inflow turbulence distortion and noise for airfoils

In this work, the interaction of grid-generated turbulence with airfoils of different thicknesses, namely, a National Advisory Committee for Aeronautics (NACA) 0008 and a NACA 0018, is investigated, leading to a deeper understanding of the influence of the airfoil geometry on the near-field flow and on the far-field pressure fluctuations. Experimentally validated lattice-Boltzmann simulations are used to analyze the flow properties in the leading-edge (LE) vicinity. The analysis of the velocity fluctuations near the LE shows that momentum is transferred from the streamwise to the transverse velocity for the NACA 0008 airfoil interacting with a large turbulence length scale. This mechanism changes with the increase in the airfoil thickness because the inflow turbulence length scale becomes comparable to the airfoil thickness in the LE region, resulting in a higher concentration of vortices near the LE oriented in the transverse direction, creating high-velocity fluctuations in the spanwise direction. The near- and far-field pressure fluctuations are analyzed to understand the impact of the inflow turbulence distortion on these parameters and the limitations of analytical methods for real airfoils. Results show that the wall-pressure fluctuations are affected by the turbulence distortion in the LE region. Thick airfoils have noise directivity patterns significantly different compared to the Amiet predictions for higher frequencies, radiating higher noise levels upstream of the LE than the thin airfoil. This is likely associated with a drastic change in the pressure fluctuation distribution near the airfoil LE region, attributed to the change in the distortion of the vortical structures in the LE area.</p

Exploratory research analysis on emissions generated in internal combustion engines

It is common knowledge that internal combustion engines have the function of transforming thermal energy into useful mechanical work. During the combustion process of the fuel and air mixture (heat generation) a quantity of gases are produced and released into the environment by the exhaust system of these engines. When these machines were invented, their creators might not have had the notion that the generated gases would be aggressors to nature. The constant population growth, the increasing demand for the use of these engines and observations of the impact in nature, among them the health and greenhouse effects, evidenced mainly from the end of the last century, led scientists to study the problem related to gaseous emissions from these machines. The present work aims to study and evaluate the emissions of internal combustion engines, their consequences both to the human health and to the environment, the evolution of government legislation and also the control mechanisms implemented to reduce these pollutants. The applied methodology is a qualitative and exploratory study of bibliographic character of theoretical and experimental works that were presented in master's dissertations, doctoral theses, scientific articles and websites of companies specialized in the subject

Wheat Production Performance In Response To Nitrogen Sidedressing And Molybdenum Leaf Application

The application of nitrogen (N) at the appropriate time can be effective for crop productivity, changing the grain yield by increasing yield components. Thus, new alternatives that enable a better application of N fertilizer are sought. The aim of this study was to evaluate the components of yield and productivity of wheat cultivated with different doses of N sidedressing and molybdenum (Mo) via leaf application, using two cultivars, CD 150 and Quartzo. The experiment was conducted in the crop years of 2013 and 2014. The experiment used a randomized, factorial 4 x 4 block design, with four replicates. Four doses of N sidedressing in the form of urea were applied (0, 30, 60, and 90 kg ha-1) during tillering. In the same period, leaf molybdic fertilizer was applied, using four dosages of Mo in the form of potassium molybdate (0, 20, 40, and 60 g ha-1). Grain number per ear (GNPE), 1,000-grain mass (TGM), hectoliter weight (HW), and grain productivity (PROD) were evaluated. N fertilizer sidedressing did not promote the yield components of either of the wheat cultivars, although the GNPE of the Quartzo cultivar increased with increasing N doses in both crop years. The increase in N fertilizer increased the PROD of both wheat cultivars. The foliar application of Mo did not promote the yield components or wheat PROD of either cultivar. The HW was influenced by N and Mo rates, and was reduced in the absence of either of these fertilizer elements, indicating that the two nutrients were dependent on each other.3752963297