Anomalous oscillations of average transient lifetimes near crises

It is common that the average length of chaotic transients appearing as a consequence of crises in dynamical systems obeys a power low of scaling with the distance from the crisis point. It is, however, only a rough trend; in some cases considerable oscillations can be superimposed on it. In this letter we report anomalous oscillations due to the intertwined structure of basins of attraction. We also present a simple geometrical model that gives an estimate of the period and amplitude of these oscillations. The results obtained within the model coincide with those yielded by computer simulations of a kicked spin model and the Henon map.Comment: 5 pages, 4 figure

Phase transitions in social impact models of opinion formation

We study phase transitions in models of opinion formation which are based on the social impact theory. Two different models are discussed: (i) a cellular--automata based model of a finite group with a strong leader where persons can change their opinions but not their spatial positions, and (ii) a model with persons treated as active Brownian particles interacting via a communication field. In the first model, two stable phases are possible: a cluster around the leader, and a state of social unification. The transition into the second state occurs for a large leader strength and/or for a high level of social noise. In the second model, we find three stable phases, which correspond either to a ``paramagnetic'' phase (for high noise and strong diffusion), a ``ferromagnetic'' phase (for small nose and weak diffusion), or a phase with spatially separated ``domains'' (for intermediate conditions).Comment: 15 pages, 4 figures, submitted for publication in Physica

Construal Levels in the Context of Sport Imagery and Performance

The purpose of this dissertation was to investigate what role abstract and concrete construal levels play in sport imagery and how they impact sport performance outcomes. Another major purpose was to provide an introduction to a new mixed methods data analysis approach and to apply the developed methodology in the context of a qualitative study investigating construal levels in sport imagery. Three studies were conducted with these purposes in mind. The first study describes a mixed methods analysis of spontaneous sport imagery. 12 elite athletes participated in semi-structured interviews about their experiences with imagery before and during competitive events. Thematic analysis was employed in the qualitative part of the study, and quantitization of co-occurring codes was employed in the quantitative part of the study. Findings from the two data sets were integrated to provide a conclusive whole. Themes that emerged identified athletes’ concrete imagery to focus on strategy generation, error correction, technique, and preparation, and athletes’ abstract imagery to focus on desirability, symbolic and verbal representations, and psychological regulation. Statistical analyses revealed that experienced effectiveness of imagery significantly differed for task type (i.e., sport tasks performed in reactive environments versus in static environments) and competition times (i.e., day before competition, during competition). The second and third studies were conducted based on findings from the first study. 30 participants (16 from table tennis and 14 from a track team, i.e., throwers and long jumpers) participated in the second study, a between-within experimental design, executing their tasks after a baseline condition and two construal level conditions which included verbal distance framings to induce low and high construal levels. 32 participants (16 from badminton and 16 from soccer teams) participated in the third study, also a between-within experimental design, executing soccer penalty shots and badminton rallies, with the verbal framing consisting of feasibility/desirability frames. Participants in the latter study also provided imagery recall information that was analyzed for content. Results from both studies supported the hypotheses that construal levels interact with task types to impact performance outcomes, such that table tennis and badminton players (performing their tasks in reactive environments) performed better in the low construal conditions than the high construal conditions, while throwers, jumpers and soccer penalty kickers (performing their tasks in static environments) performed better in the high construal conditions compared to the low construal conditions. Analysis of the imagery reports indicated that construal level frames impacted the content of athletes’ imagery (in terms of linguistic make-up as well as distance and detail provided); however, imagery did not act as a mediator as no evidence was found that it subsequently impacted performance outcomes

Coordination of Decisions in a Spatial Agent Model

For a binary choice problem, the spatial coordination of decisions in an agent community is investigated both analytically and by means of stochastic computer simulations. The individual decisions are based on different local information generated by the agents with a finite lifetime and disseminated in the system with a finite velocity. We derive critical parameters for the emergence of minorities and majorities of agents making opposite decisions and investigate their spatial organization. We find that dependent on two essential parameters describing the local impact and the spatial dissemination of information, either a definite stable minority/majority relation (single-attractor regime) or a broad range of possible values (multi-attractor regime) occurs. In the latter case, the outcome of the decision process becomes rather diverse and hard to predict, both with respect to the share of the majority and their spatial distribution. We further investigate how a dissemination of information on different time scales affects the outcome of the decision process. We find that a more ``efficient'' information exchange within a subpopulation provides a suitable way to stabilize their majority status and to reduce ``diversity'' and uncertainty in the decision process.Comment: submitted for publication in Physica A (31 pages incl. 17 multi-part figures

Search engine effects on news consumption: Ranking and representativeness outweigh familiarity in news selection

While individuals' trust in search engine results is well-supported, little is known about their preferences when selecting news. We use web-tracked behavioral data across a 2-month period (280 participants) and we analyze three competing factors, two algorithmic (ranking and representativeness) and one psychological (familiarity), that could influence the selection of search results. We use news engagement as a proxy for familiarity and investigate news articles presented on Google search pages (n = 1221). We find a significant effect of algorithmic factors but not of familiarity. We find that ranking plays a lesser role for news compared to non-news, suggesting a more careful decision-making process. We confirm that Google Search drives individuals to unfamiliar sources, and find that it increases the diversity of the political audience of news sources. We tackle the challenge of measuring social science theories in contexts shaped by algorithms, demonstrating their leverage over the behaviors of individuals

Do Athletes Imagine Being the Best, or Crossing the Finish Line First? A Mixed Methods Analysis of Construal Levels in Elite Athletes' Spontaneous Imagery

The purpose of this article is to illustrate data transformation in a mixed methods research phenomenological study, investigating how athletes use concrete and abstract spontaneous imagery in and around competition. To achieve this, we combined the application of co-occurring codes and numerical transformation in a novel way. A thematic analysis of qualitative interviews with 12 elite athletes identified concrete imagery to focus on strategy generation, error correction, technique, and preparation, and abstract imagery to focus on desirability, symbolic and verbal representations, and regulation of affect, arousal, and mastery. Statistical analysis identified that subjective effectiveness of imagery significantly differed for sport type (reactive/static) and competition times. Researchers wishing to apply statistical analyses to qualitative data are encouraged to employ our methodology

Image Acquisition System based on Synchronized High Resolution Gigabit Ethernet Cameras

Over the last few years, the huge rise in various computer vision applications canbe observed. They are widely used in such areas like video surveillance, medicaldiagnostics, biometrics recognition, the automotive or military industries. Mostof these solutions take advantage of high-resolution cameras in order to obtainhigh quality images. Surprisingly, little attention is paid in the literature tothe practical implementation of off-the-shelf image acquisition systems. Mostavailable solutions are composed of custom developed electronic devices whichuse specialized multi-core DSPs and / or FPGA technology. Therefore, in thispaper the novel realization of the scalable and comprehensive image acquisitionsystem based on synchronized high resolution Gigabit Ethernet camerasis presented. The proposed solution allows the connection of multiple camerastogether with any number of external illumination modules. Selected devicescan be synchronized with each other in user-defined configurations. Hence,designed solution can be easily integrated in both simple and complex applications.Authors describe in detail design and implementation processes of theproposed platform. The performance issues that can occur in such systems arepresented and discussed. Obtained results are encouraging and useful for thedevelopment of similar solutions