A saturated strategy robustly ensures stability of the cooperative equilibrium for Prisoner's dilemma

We study diffusion of cooperation in a two-population game in continuous time. At each instant, the game involves two random individuals, one from each population. The game has the structure of a Prisoner's dilemma where each player can choose either to cooperate (c) or to defect (d), and is reframed within the field of approachability in two-player repeated game with vector payoffs. We turn the game into a dynamical system, which is positive, and propose a saturated strategy that ensures local asymptotic stability of the equilibrium (c, c) for any possible choice of the payoff matrix. We show that there exists a rectangle, in the space of payoffs, which is positively invariant for the system. We also prove that there exists a region in the space of payoffs for which the equilibrium solution (d, d) is an attractor, while all of the trajectories originating outside that region, but still in the positive quadrant, are ultimately bounded in the rectangle and, under suitable assumptions, converge to the solution (c, c)

Socialism and entrepreneurship: A rational choice approach to an issue of compatibility.

A theoretical study of the feasibility of socialism. Politically, socialism is characterised by equality, democracy and liberty. Economically, it is assumed (i) that the feasibility of socialism depends upon its ability to generate growth, and (ii) that growth is secured through entrepreneurial activity. Economic theory is used to delineate the concept of entrepreneurship and to explore the nature and limitations of capitalist entrepreneurship and political theory is used to identify possible incompatibilities between socialism and entrepreneurship. Underlying many of these arguments is a claim for the existence of a trade-off between efficiency and equality. The capacity of market socialism to either transcend or minimise this trade-off is considered. Three forms of market socialism are examined. The first is drawn from Joseph Carens' work on moral incentives, the second from theories of the labour-managed firm and the third from new public management. The socialist credentials and capacity of each to generate entrepreneurial activity are appraised. Examples drawn upon include Israeli Kibbutzim, the Spanish Mondragon cooperative, British nationalised industries and the Japanese computer industry. Economic new institutionalism, welfare economics and Austrian economic theory are all on occasions used but the principle methodology is rational choice. Specifically, theory principle agent analysis and William Niskanen's of the budget - using bureaucracy shown capable, illuminating discussion. Given even the assumption of egoism it is argued that through careful institutional and organisational design, tensions between socialism and entrepreneurship can be alleviated

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

MANAGING COMMUNITY: A PHILOSOPHICAL ANALYSIS OF PRAXIS

If communities are to become a viable means of implementing social policy then community practitioners must individually examine their personal praxis. Therefore, in discovering a community's aims and objectives, a management model is needed that offers every practitioner a reflexive means of understanding peoples' beliefs, values, and attitudes. This proposition is critically examined through a philosophical framework that explores individuals' diverse perspectives on community, derived from their adherence to contending ontological and epistemological propositions about the social world, and its related ethical and motivational dimensions. Following a philosophical analysis, the taxonomy of social reality perspectives, developed by Dixon (2003) and Dixon and Dogan (2002; 2003a, b, c, d; 2004). is systematically used to explore the contending views on social reality. Thus, methodological configurations are associated with logical categories, (1) naturalist agency, underpinning the self-interested (free-riding) homo economicus\ (2) naturalist structuralism, underpinning the obligation driven homo hierarchus; (3) hermeneutic structuralism, underpinning the conversation-saturated homo sociologicus (Archer, 2000: 4); and (4) hermeneutic agency, underpinning homo existentialis. The disciplines of social psychology, ethics, and political science are employed to explore selected facets of human nature, moral principles, and political ideology chosen, by associates of each set of methodological configurations, in particular relational situations. Informed by this investigation a sample of community practitioners were questioned about their praxis. This reveals that a substantial majority understand and accept an objective and knowable social worid where people are self-interested. Therefore, these practitioners perceive community as a setting where they can influence the decisions of others through discourse and judge its ethical merits by the degree of loyalty and obligation extended to their projects. Thus, it is apparent that community practitioners should evaluate their praxis, through critical self-reflection, if they are to develop suitably robust and durable symbiotic relationships with adherents to each of the four social reality perceptions. This research leads to a new logic, based on the innovative interpretation of ontotogical and epistemotogical configurations offered in the seminal work of Bhaskar (1978 and 1979) and Archer (1989, 1995, 2000 and 2003). Here, an emerging social ontology informs the construction of more specific theories conceming the dynamics of community in identifiable localities. Therefore, it now becomes possible to construct a management model, incorporating contending social realities, the techniques of mediation and the results of changing cognition and cognitive dissonance, that facilitates community practitioner's critical self-reflection and construction of managerial strategies based on community member's contending perceptions of social reality

The role of visual adaptation in cichlid fish speciation

D. Shane Wright (1) , Ole Seehausen (2), Ton G.G. Groothuis (1), Martine E. Maan (1) (1) University of Groningen; GELIFES; EGDB(2) Department of Fish Ecology & Evolution, EAWAG Centre for Ecology, Evolution and Biogeochemistry, Kastanienbaum AND Institute of Ecology and Evolution, Aquatic Ecology, University of Bern.In less than 15,000 years, Lake Victoria cichlid fishes have radiated into as many as 500 different species. Ecological and sexual sel ection are thought to contribute to this ongoing speciation process, but genetic differentiation remains low. However, recent work in visual pigment genes, opsins, has shown more diversity. Unlike neighboring Lakes Malawi and Tanganyika, Lake Victoria is highly turbid, resulting in a long wavelength shift in the light spectrum with increasing depth, providing an environmental gradient for exploring divergent coevolution in sensory systems and colour signals via sensory drive. Pundamilia pundamila and Pundamilia nyererei are two sympatric species found at rocky islands across southern portions of Lake Victoria, differing in male colouration and the depth they reside. Previous work has shown species differentiation in colour discrimination, corresponding to divergent female preferences for conspecific male colouration. A mechanistic link between colour vision and preference would provide a rapid route to reproductive isolation between divergently adapting populations. This link is tested by experimental manip ulation of colour vision - raising both species and their hybrids under light conditions mimicking shallow and deep habitats. We quantify the expression of retinal opsins and test behaviours important for speciation: mate choice, habitat preference, and fo raging performance

Topology Reconstruction of Dynamical Networks via Constrained Lyapunov Equations

The network structure (or topology) of a dynamical network is often unavailable or uncertain. Hence, we consider the problem of network reconstruction. Network reconstruction aims at inferring the topology of a dynamical network using measurements obtained from the network. In this technical note we define the notion of solvability of the network reconstruction problem. Subsequently, we provide necessary and sufficient conditions under which the network reconstruction problem is solvable. Finally, using constrained Lyapunov equations, we establish novel network reconstruction algorithms, applicable to general dynamical networks. We also provide specialized algorithms for specific network dynamics, such as the well-known consensus and adjacency dynamics.Comment: 8 page

2012 IMSAloquium, Student Investigation Showcase

Through SIR and its partnerships, IMSA students engage in rich opportunities to pursue compelling questions of interest, conduct investigations, engage with extraordinary advisors, communicate findings, and ultimately impact society.https://digitalcommons.imsa.edu/archives_sir/1004/thumbnail.jp

Temporal and social discounting of pain and illness

Unhealthy behaviour often entails short-term indulgence at the expense of long-term health. This thesis examines an hypothesis that temporal discounting, a measure of the extent to which a person devalues delayed benefit, predicts unhealthy behaviour. The work also evaluates temporal discounting as a psychological model for unhealthy behaviour, in particular unhealthy behaviour that is enacted in spite of healthy goals, and behaviour with painful consequences. Studies examining relationships between temporal discounting and health behaviour are systematically reviewed, with the finding that discounting of reward correlates with many forms of appetitive unhealthy behaviour. It is proposed that while steep discounting predisposes to unhealthy behaviour, goal-incongruent behaviour is better explained by the interfering effect of prelearned or innate values. Also, conventional discounting fails to account for the fact that many people prefer to expedite inevitable pain or illness. An explanation is that people dislike waiting for pain, termed ‘dread’. The empirical work of this thesis establishes how dread depends on delay, by asking participants to titrate the timing and severity of their own pain or that of others. For the average participant, the dread of pain accumulated at a decreasing rate as pain was delayed. Dread was found to be less marked when deciding on behalf of socially close others. Unexpectedly a tendency to dread future pain in one-off choices did not predict saving a budget of pain relief in sequential choices. Further experiments examined social discounting for pain, finding that participants appear more averse to causing pain in others than in themselves, a tendency that is discounted with social distance. Conclusions are that temporal discounting of reward is a promising marker of appetitive unhealthy behaviour, with a considerable evidence base, while dread offers a candidate marker for engagement in health-promoting behaviour with painful consequences, a possibility which demands further investigation.Open Acces