A “Cognitive Miser” Theory of Cooperators Advantage

1991 ◽  
Vol 85 (2) ◽  
pp. 515-528 ◽  
Author(s):  
John Orbell ◽  
Robyn M. Dawes
Keyword(s):  
Boundary Conditions ◽  
Cooperative Behavior ◽  
Empirical Support ◽  
Social Dilemma ◽  
Expected Payoff ◽  
New Model ◽  
Behavioral Decision ◽  
Cognitive Miser

We propose a new model of cooperators' advantage depending neither on supplementary incentives nor on cooperators' capacity to recognize, and play selectively with, other cooperators. It depends, rather, on players' making the play-no play decision by the heuristic of projecting their own “cooperate-defect” choices onto potential partners. Cooperators offer to play more often, and fellow cooperators will more often accept their offer. When certain boundary conditions are met, this results in a higher expected payoff for cooperators than for defectors. Empirical support for this heuristic is suggested by expectations data from related social dilemma experiments. Moreover, its use can be justified in Bayesean terms. Our model brings behavioral decision theory's “cognitive miser” paradigm to bear on interdisciplinary concern with the evolution of cooperative behavior and shows how, if other mechanisms provide a suitable “initial kick,” cooperation can evolve in the absence of iteration and in large, mobile societies.

scholarly journals Experimental study of wall boundary conditions for large-eddy simulation

2001 ◽  
Vol 446 ◽  
pp. 309-320 ◽  
Author(s):  
IVAN MARUSIC ◽  
GARY J. KUNKEL ◽  
FERNANDO PORTÉ-AGEL
Keyword(s):  
Boundary Layer ◽  
Boundary Condition ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Large Eddy Simulation ◽  
Boundary Conditions ◽  
Streamwise Velocity ◽  
New Model ◽  
Eddy Simulation ◽  
Large Eddy

An experimental investigation was conducted to study the wall boundary condition for large-eddy simulation (LES) of a turbulent boundary layer at Rθ = 3500. Most boundary condition formulations for LES require the specification of the instantaneous filtered wall shear stress field based upon the filtered velocity field at the closest grid point above the wall. Three conventional boundary conditions are tested using simultaneously obtained filtered wall shear stress and streamwise and wall-normal velocities, at locations nominally within the log region of the flow. This was done using arrays of hot-film sensors and X-wire probes. The results indicate that models based on streamwise velocity perform better than those using the wall-normal velocity, but overall significant discrepancies were found for all three models. A new model is proposed which gives better agreement with the shear stress measured at the wall. The new model is also based on the streamwise velocity but is formulated so as to be consistent with ‘outer-flow’ scaling similarity of the streamwise velocity spectra. It is therefore expected to be more generally applicable over a larger range of Reynolds numbers at any first-grid position within the log region of the boundary layer.

Buckling Analysis of Tubular Strings in Horizontal Wells

SPE Journal ◽  
2014 ◽  
Vol 20 (02) ◽  
pp. 405-416 ◽  
Author(s):  
Wenjun Huang ◽  
Deli Gao ◽  
Fengwu Liu
Keyword(s):  
Boundary Conditions ◽  
Axial Force ◽  
Shear Force ◽  
Virtual Work ◽  
Bending Moment ◽  
Horizontal Wells ◽  
Comprehensive Description ◽  
New Model ◽  
First Category ◽  
Second Category

Summary A new buckling equation in horizontal wells is derived on the basis of the general bending and twisting theory of rods. The boundary conditions of a long tubular string are divided into two categories: the sum of the virtual work of bending moment and shear force at the ends of tubular strings is equal to zero, and the sum of the virtual work of bending moment and shear force at the ends is not equal to zero. Buckling solutions under different boundary conditions are obtained by solving the new buckling model. For the boundary conditions of the first category, the buckling solutions are identical with previous results. For the boundary conditions of the second category, the buckling solutions are different from the results under the boundary conditions of the first category. The results indicate that buckling behaviors depend on both the axial force and the boundary conditions. Compared with previous results, buckling solutions of the new model provide a more comprehensive description of tubular-buckling behaviors.

Three alternative versions of the theory for a Timoshenko–Ehrenfest beam on a Winkler–Pasternak foundation

2020 ◽  
pp. 108128652094777
Author(s):  
Giulio Maria Tonzani ◽  
Isaac Elishakoff
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Detailed Comparison ◽  
Vibration Frequencies ◽  
Pasternak Foundation ◽  
New Model ◽  
Simply Supported ◽  
Model Based

This paper analyzes the free vibration frequencies of a beam on a Winkler–Pasternak foundation via the original Timoshenko–Ehrenfest theory, a truncated version of the Timoshenko–Ehrenfest equation, and a new model based on slope inertia. We give a detailed comparison between the three models in the context of six different sets of boundary conditions. In particular, we analyze the most common combinations of boundary conditions deriving from three typical end constraints, namely the simply supported end, clamped end, and free end. An interesting intermingling phenomenon is presented for a simply-supported (S-S) beam together with proof of the ‘non-existence’ of zero frequencies for free-free (F-F) and simply supported-free (S-F) beams on a Winkler–Pasternak foundation.

scholarly journals Boring Thoughts and Bored Minds: The MAC Model of Boredom and Cognitive Engagement

2017 ◽  
Author(s):  
Erin Corwin Westgate
Keyword(s):  
Empirical Support ◽  
Cognitive Engagement ◽  
The Other ◽  
Cognitive Demands ◽  
New Model ◽  
Attentional Deficits ◽  
Attentional Engagement ◽  
Mental Resources

What is boredom? We review environmental, attentional, and functional theories and present a new model that describes boredom as an affective indicator of unsuccessful attentional engagement in valued goal-congruent activity. According to the Meaning and Attentional Components (MAC) model, boredom is the result of (a) an attentional component, namely mismatches between cognitive demands and available mental resources, and (b) a meaning component, namely mismatches between activities and valued goals (or the absence of valued goals altogether). We present empirical support for four novel predictions made by the model: (1) Deficits in attention and meaning each produce boredom independently of the other; (2) there are different profiles of boredom that result from specific deficits in attention and meaning; (3) boredom results from two types of attentional deficits, understimulation and overstimulation; and (4) the model explains not only when and why people become bored with external activities, but also when and why people become bored with their own thoughts. We discuss further implications of the model, such as when boredom motivates people to seek interesting versus enjoyable activities.

The Development of a Partially Averaged Navier-Stokes KSKL Model

2021 ◽  
Author(s):  
Maarten Klapwijk ◽  
Thomas Lloyd ◽  
Guilherme Vaz
Keyword(s):  
Kinetic Energy ◽  
Boundary Conditions ◽  
Multiphase Flow ◽  
Eddy Viscosity ◽  
Navier Stokes ◽  
New Model ◽  
Cell Height ◽  
Sst Model ◽  
Energy Ratios ◽  
Model Derivation

Abstract A new partially averaged Navier-Stokes (PANS) closure is derived based on the KSKL model. The aim of this new model is to incorporate the desirable features of the KSKL model, compared to the SST model, into the PANS framework. These features include reduced eddy-viscosity levels, a lower dependency on the cell height at the wall, well-defined boundary conditions, and improved iterative convergence. As well as the new model derivation, the paper demonstrates that these desirable features are indeed maintained, for a range of modeled-to-total turbulence kinetic energy ratios (f_k), and even for multiphase flow.

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