Search results for "Mathematica"

Evolution of impatience: The example of the Farmer-Sheriff game

2015

The literature on the evolution of impatience, focusing on one-person decision problems, often finds that evolutionary forces favor the more patient individuals. This paper shows that in games where equilibrium involves threat of punishment there are forces generating an evolutionary advantage to the impatient. In particular, it offers a two-population example where evolutionary forces favor impatience in one group while favoring patience in the other. Moreover, efficiency may also favor impatient individuals. In our example, it is efficient for one population to evolve impatience and for the other to develop patience. Yet, evolutionary forces move the opposite direction. Fil: Levine, David…

Comparison of non-Markovianity criteria in a qubit system under random external fields

2013

We give the map representing the evolution of a qubit under the action of non-dissipative random external fields. From this map we construct the corresponding master equation that in turn allows us to phenomenologically introduce population damping of the qubit system. We then compare, in this system, the time-regions when non-Markovianity is present on the basis of different criteria both for the non-dissipative and dissipative case. We show that the adopted criteria agree both in the non-dissipative case and in the presence of population damping.

A Population-Based Approach to the Resource-Constrained Project Scheduling Problem

2004

We present a population-based approach to the RCPSP. The procedure has two phases. The first phase handles the initial construction of a population of schedules and these are then evolved until high quality solutions are obtained. The evolution of the population is driven by the alternative application of an efficient improving procedure for locally improving the use of resources, and a mechanism for combining schedules that blends scatter search and path relinking characteristics. The objective of the second phase is to explore in depth those vicinities near the high quality schedules. Computational experiments on the standard j120 set, generated using ProGen, show that our algorithm produ…

A Side-by-Side Single Sex Age-Structured Human Population Dynamic Model: Exact Solution and Model Validation

2008

A side-by-side single sex age-structured population dynamic model is presented in this paper. The model consists of two coupled von Foerster-McKendrick-type quasi-linear partial differential equations, two initial conditions, and two boundary conditions. The state variables of the model are male and female population densities. The solutions of these partial differential equations provide explicit time and age dependence of the variables. The initial conditions define the male and female population densities at the initial time, while the boundary conditions compute the male and female births at zero-age by using fertility rates. The assumptions of the nontime-dependence of the death and fe…

ON THE EXISTENCE OF LIMIT CYCLES IN OPINION FORMATION PROCESSES UNDER TIME PERIODIC INFLUENCE OF PERSUADERS

2008

This paper concerns a model of opinion formation in a population of interacting individuals under the influence of external leaders or persuaders, which act in a time periodic fashion. The model is formulated within a general framework inspired to a discrete generalized kinetic approach, which has been developed in Ref. 6. It is expressed by a system of non-autonomous nonlinear ordinary differential equations. The dynamics of such a system is investigated and the existence of a globally asymptotically stable periodic solution is analytically proved in three example cases, each one corresponding to a different quantitative choice of the actions of the persuaders. Equivalently, in three part…

Kształtowanie intuicji matematycznych w trakcie pozaszkolnej aktywności dziecka

2016

Działania arytmetyczne w początkowej edukacji matematycznej - kształtowanie pojęć czy rozwijanie nawyków rachunkowych?

2014

Rodzice jako partnerzy procesu rozbudzania dziecięcej aktywności matematycznej

2017

Children learn in a spontaneous and continuous way: when they look at an object, paying more attention to it, or when they notice something accidentally, when they perform simple actions of daily routine, or even when they turn to a grown-up with a question. Therefore, forming proper mathematical intuition should not be limited merely to activities at school, but should proceed natural, also during everyday activities, while playing games or talking to other children or the parents. The individual’s own activity plays a particular role in the development of mathematical skills in children. And it is parents who have the greatest say as regards the lines along which the child’s activity is d…

Generalized curved beam on elastic foundation solved by Transfer Matrix Method

2011

A solution of space curved bars with generalized Winkler soil found by means of Transfer Matrix Method is presented. Distributed, concentrated loads and imposed strains are applied to the beam as well as rigid or elastic boundaries are considered at the ends. The proposed approach gives the analytical and numerical exact solution for circular beams and rings, loaded in the plane or perpendicular to it. A well-approximated solution can be found for general space curved bars with complex geometry. Elastic foundation is characterized by six parameters of stiffness in different directions: three for rectilinear springs and three for rotational springs. The beam has axial, shear, bending and tor…

Bounds on plastic strains for elastic plastic structures in plastic shakedown conditions

2007

The problem related to the computation of bounds on plastic deformations for structures in plastic shakedown condition (alternating plasticity) is studied. In particular, reference is made to structures discretized by finite elements constituted by elastic perfectly plastic material and subjected to a special combination of fixed and cyclic loads. The load history is known during the steady-state phase, but it is unknown during the previous transient phase; so, as a consequence, it is not possible to know the complete elastic plastic structural response. The interest is therefore focused on the computation of bounds on suitable measures of the plastic strain which characterizes just the fir…