Zero-Temperature Freezing in Three-Dimensional Kinetic Ising Model

We investigate the long-time properties of the Ising-Glauber model on a periodic cubic lattice after a quench to zero temperature. In contrast to the conventional picture from phase-ordering kinetics, we find: (i) Domains at long time are highly interpenetrating and topologically complex, with average genus growing algebraically with system size. (ii) The long-time state is almost never static, but rather contains "blinker" spins that can flip ad infinitum with no energy cost. (iii) The energy relaxation has a complex time dependence with multiple characteristic time scales, the longest of which grows exponentially with system size.Comment: 4 pages, 6 figures, 2-column revtex 4 forma

Simulation of an Optional Strategy in the Prisoner's Dilemma in Spatial and Non-spatial Environments

This paper presents research comparing the effects of different environments on the outcome of an extended Prisoner's Dilemma, in which agents have the option to abstain from playing the game. We consider three different pure strategies: cooperation, defection and abstinence. We adopt an evolutionary game theoretic approach and consider two different environments: the first which imposes no spatial constraints and the second in which agents are placed on a lattice grid. We analyse the performance of the three strategies as we vary the loner's payoff in both structured and unstructured environments. Furthermore we also present the results of simulations which identify scenarios in which cooperative clusters of agents emerge and persist in both environments.Comment: 12 pages, 8 figures. International Conference on the Simulation of Adaptive Behavio

Fate of 2D Kinetic Ising Ferromagnets and Critical Percolation Crossing Probabilities

We present evidence for a deep connection between the zero-temperature coarsening of the two-dimensional kinetic Ising model (KIM) and critical continuum percolation. In addition to reaching the ground state, the KIM can also fall into a variety of topologically distinct metastable stripe states. The probability to reach a stripe state that winds a times horizontally and b times vertically on a square lattice with periodic boundary conditions equals the corresponding exactly-solved critical percolation crossing probability P_{a,b} for a spanning path with winding numbers a and b.Comment: 4 pages, 4 figure, 2-column revtex4 format. Revision contains material about the TDGL and is nearly identical to the final published versio

Zero-Temperature Relaxation of Three-Dimensional Ising Ferromagnets

We investigate the properties of the Ising-Glauber model on a periodic cubic lattice of linear dimension L after a quench to zero temperature. The resulting evolution is extremely slow, with long periods of wandering on constant energy plateaux, punctuated by occasional energy-decreasing spin-flip events. The characteristic time scale tau for this relaxation grows exponentially with the system size; we provide a heuristic and numerical evidence that tau exp(L^2). For all but the smallest-size systems, the long-time state is almost never static. Instead the system contains a small number of "blinker" spins that continue to flip forever with no energy cost. Thus the system wanders ad infinitum on a connected set of equal-energy blinker states. These states are composed of two topologically complex interwoven domains of opposite phases. The average genus g_L of the domains scales as L^gamma, with gamma~1.7; thus domains typically have many holes, leading to a "plumber's nightmare" geometry.Comment: 12 pages, 20 figure, 4 tables, revtex4-1 forma

Simulation game as a tool for learning decision-making and consequences of wrong decision in logistics supply chain

Artykuł prezentuje zastosowanie wdrożonego przez autorów systemu informatycznego do prowadzenia logistycznej gry decyzyjnej, zwracając szczególną uwagę na zależności występujące pomiędzy podejmowanymi przez uczestników kolejnymi decyzjami oraz konsekwencjami popełnionych błędów dla prowadzonego przez nich przedsiębiorstwa, jak i dla funkcjonowania pozostałych przedsiębiorstw działających na tym samym rynku. W oparciu o przeprowadzone badania ankietowe autorzy wskazują na działania związane z przygotowaniem decyzji, które są przyczyną największych trudności oraz błędy popełniane przez największą liczbę uczestników. Popełnianie tych błędów sprawia, że poznawanie zależności występujących w systemie logistycznym przedsiębiorstwa w warunkach rzeczywistych byłoby dla niego niebezpieczne, stąd wykorzystanie w tym celu gry symulacyjnej zdaniem autorów jest jak najbardziej wskazane. Potwierdzeniem tej oceny autorów są zaprezentowane w artykule wyniki badań ankietowych.The global economy requires the development of a complicated network of connections between geographically distant companies. This increases the importance of logistics and management in the logistics supply chain. The modern manager has to be aware of the importance of decisions taken in this area. A useful tool that allows him to realize the importance of this and get to know occurring dependences is decision-making simulation game. The paper presents designed and implemented in the Department of Computer Science of the Faculty of Electrical Engineering, Automatics, Computer Science and Electronics and used in the Department of Economics and Management in Industry of Faculty of Mining and Geoengineering AGH IT platform for logistics simulation game LoGame, with particular attention to the interdependence between the decisions made by the participants and the consequences of mistakes for the managed firms and for the functioning of other companies operating in the same market. Based on surveys, the authors point to the activities related to the preparation of decisions that cause the greatest difficulties. Mistakes made by the largest number of participants are also identified. Committing these mistakes makes the learning of connections in the logistics system of enterprises in real conditions dangerous and very costly for the company, and therefore such use to the simulation game is highly recommended. This is confirmed by the results of surveys conducted among participants in the decision-making simulation game, confirming the achievement of results associated with realizing the consequences of the decisions taken in the logistics supply chain

The effect of height and BMI on computer dynamic posturography parameters in women

The human body’s posture control is a complex system of organs and mechanisms which controls the body’s centre of gravity (COG) over its base of support (BOS). Computerised Dynamic Posturography (CDP) allows for the quantitativeand objective assessment of the sensory and motor components of the body’s posture control system as well as of the integration and adaptation mechanisms in the central nervous system. The aim of this study was to assess the relationships between the body’s height and BMI on CDP results in a group of young healthy women without any clinical symptoms of balance disorders. It was found that the MS depended significantly on the height and BMI of the subjects as well as on the SOT conditions. As the height and BMI increased the MS value decreased. The postural response latency (LC) in the MCT statistically significantly depended only on height and showed a positive correlation. The postural response latency increased with height. The postural response amplitude for both right and left lower limbs significantly depended on height and BMI, but only for the backward movement of the platform. The response amplitude for all platform translations under all MCT conditions increased with height and BMI. The body’s resultant imbalance caused by the platform perturbations in the ADT were greater in shorter people and those with a lower BMI

Investigations and modernizations of buckets of surface mining machines

Przedstawiono wyniki prac eksperymentalnych i projektowych oraz analiz numerycznych zmierzających do optymalizacji kosztów eksploatacji czerpaków stosowanych w Kopalni Węgla Brunatnego Turów. Zaprezentowano kompletne podejście do procesu projektowania i optymalizacji uwzględniające wyniki badań w rzeczywistych warunkach urabiania i wykorzystujące najnowocześniejsze narzędzia numeryczne do realizacji procesu konstruowania tego typu obiektów. Efektem prac są dwa projekty czerpaków z zębami wymiennymi i stałymi, które w znaczący sposób poprawią wskaźniki techniczno-eksploatacyjne i przełożą się na realne oszczędności uzyskiwane przez użytkowników.Results of experimental tests, design work and numerical analyses aimed to optimize the operating costs of buckets used in the Turow Surface Mine. In the presented approach of designing and optimization, results of tests in real conditions of mining are taken into account. Also modern numerical tools support the process of designing such facilities. Results of the presented work are two buckets with quick replaceable and permanent teeth, which significantly improve the technical and operational indicators and enable real savings achieved by the users

The human balance system and gender

The human body balance system is a complex system of organs and mechanisms, which generate postural reactions to counter the displacement from the equilibrium position of the body centre of gravity, and which control eye movement in order to maintain a stable image of the environment. Computerised Dynamic Posturography (CDP) allows for a quantitative and objective assessment of the sensory and motor components of the body balance control system as well as of the integration and adaptive mechanisms in the central nervous system. The aim of this study was to determine the differences, when maintaining body balance, based on the gender of young, healthy people using CDP. The study was carried out on a group of 43 healthy subjects by comparing the effectiveness of the balance system in 22 women and 21 men aged between 20 and 26 years, between 171 and 177 cm in height, and without any clinical symptoms of balance disorders. The men and women were selected such that they did not differ significantly in height and BMI. Using the Equitest posturograph manufactured by NeuroCom International Inc. the following tests were performed: Sensory Organisation Test (SOT), Motor Control Test (MCT) and the Adaptation Test (ADT). The gender of young healthy individuals without any clinical symptoms of balance disorders also does not affect the effectiveness of the sensory system and the use of this signal in maintaining body balance

Ain’t nothing like family:female brown bears share their home range with relatives

Abstract Sociality in animal populations is a continuum, and interactions between conspecifics are meaningful for all vertebrates. Ignorance of social structures can lead to misunderstanding their ecology and, consequently, to unsuccessful species management. Here, we combined genetic and spatial data on radio-collared brown bears (Ursus arctos) to investigate kin-related home range overlap and kin-related centroid distance within central and eastern Finland. We found that the extent of home range overlap was positively correlated with relatedness among adult females. In addition, home range centroid distance decreased as relatedness increased. Moreover, there were significant differences between the two studied regions: female brown bears in central Finland were more closely related to each other, and the sizes of their home ranges were larger than those in eastern Finland. The smaller home ranges and lower degree of relatedness among bears in eastern Finland might be a result of the substantially higher hunting pressure in the area, combined with immigration of new unrelated individuals from Russia