Reinforcement Learning Dynamics in Social Dilemmas

In this paper we replicate and advance Macy and Flache\'s (2002; Proc. Natl. Acad. Sci. USA, 99, 7229–7236) work on the dynamics of reinforcement learning in 2�2 (2-player 2-strategy) social dilemmas. In particular, we provide further insight into the solution concepts that they describe, illustrate some recent analytical results on the dynamics of their model, and discuss the robustness of such results to occasional mistakes made by players in choosing their actions (i.e. trembling hands). It is shown here that the dynamics of their model are strongly dependent on the speed at which players learn. With high learning rates the system quickly reaches its asymptotic behaviour; on the other hand, when learning rates are low, two distinctively different transient regimes can be clearly observed. It is shown that the inclusion of small quantities of randomness in players\' decisions can change the dynamics of the model dramatically.Reinforcement Learning; Replication; Game Theory; Social Dilemmas; Agent-Based; Slow Learning

Kink fluctuation asymptotics and zero modes

In this paper we propose a refinement of the heat kernel/zeta function treatment of kink quantum fluctuations in scalar field theory, further analyzing the existence and implications of a zero energy fluctuation mode. Improved understanding of the interplay between zero modes and the kink heat kernel expansion delivers asymptotic estimations of one-loop kink mass shifts with remarkably higher precision than previously obtained by means of the standard Gilkey-DeWitt heat kernel expansion.Comment: 21 pages, 8 figures, to be published in The European Physical Journal

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analysed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies

On the semiclassical mass of S2{\mathbb S}^2-kinks

One-loop mass shifts to the classical masses of stable kinks arising in a massive non-linear ${\mathbb S}^2$-sigma model are computed. Ultraviolet divergences are controlled using the heat kernel/zeta function regularization method. A comparison between the results achieved from exact and high-temperature asymptotic heat traces is analyzed in depth.Comment: RevTex file, 15 pages, 2 figures. Version to appear in Journal of Physics

On domain walls in a Ginzburg-Landau non-linear S^2-sigma model

The domain wall solutions of a Ginzburg-Landau non-linear $S^2$-sigma hybrid model are unveiled. There are three types of basic topological walls and two types of degenerate families of composite - one topological, the other non-topological- walls. The domain wall solutions are identified as the finite action trajectories (in infinite time) of a related mechanical system that is Hamilton-Jacobi separable in sphero-conical coordinates. The physical and mathematical features of these domain walls are thoroughly discussed.Comment: 26 pages, 18 figure

Young with Down Syndrome and recreation swimming activity: Inclusion posibilities

El propósito del estudio fue analizar las percepciones de los agentes participantes y los factores que inciden en la inclusión de un niño con síndrome de Down (SD) en un programa de natación recreativa. Los participantes fueron: un joven con SD, nueve jóvenes sin discapacidad diagnosticada, la monitora de natación, el coordinador de la actividad y la madre del niño con SD. El presente estudio, basado en una metodología cualitativa, recogió la información a través de entrevistas semi-estructuradas, observación sistemática y diario de la investigadora. La utilización de un proceso inductivo permitió categorizar la información y obtener los siguientes resultados: es necesaria una mayor coordinación entre los agentes implicados, adaptar el programa en función de las características de todos los participantes, mejorar la formación específica de los técnicos responsables y la fluidez de la comunicación entre los agentes implicados para posibilitar la inclusión del niño con SD a través de la natación recreativaThe purpose of this study was to analyse the perceptions of the participant agents and factors affecting the inclusion of a child with Down syndrome (DS) in a recreational swimming activity program. Program participants included: a child with DS, nine children without diagnosed disabilities, the swimming instructor, the mother of a child with DS and the coordinator of the activity. This study was based on qualitative research approach and data were collected through semi-structured interviews, systematic observation and research diary. The following results were obtained after the inductive process: the need of greater coordination among those involved, designs appropriate programs based on the characteristics of all participants, improve specific training of technicians responsible as well as improve the communication of the agents participating in order to enable the inclusion of a child with DS in a recreational swimming activit

Diode laser induced chemical vapor deposition of WSix on TiN from WF6 and SiH4

Presents a study that reported the development of a compact and inexpensive laser direct writing system for the deposition of tungsten and tungsten silicides using a 1 W diode laser array emitting at 796 nm. Reason for the difficulty to introduce laser processing in a manufacturing environment; Problems related to the use of diode lasers; Characteristics of the lines obtained in both static and dynamic reactors

Advanced content-based semantic scene analysis and information retrieval: the SCHEMA project

The aim of the SCHEMA Network of Excellence is to bring together a critical mass of universities, research centers, industrial partners and end users, in order to design a reference system for content-based semantic scene analysis, interpretation and understanding. Relevant research areas include: content-based multimedia analysis and automatic annotation of semantic multimedia content, combined textual and multimedia information retrieval, semantic -web, MPEG-7 and MPEG-21 standards, user interfaces and human factors. In this paper, recent advances in content-based analysis, indexing and retrieval of digital media within the SCHEMA Network are presented. These advances will be integrated in the SCHEMA module-based, expandable reference system

Scalar and tensorial topological matter coupled to (2+1)-dimensional gravity:A.Classical theory and global charges

We consider the coupling of scalar topological matter to (2+1)-dimensional gravity. The matter fields consist of a 0-form scalar field and a 2-form tensor field. We carry out a canonical analysis of the classical theory, investigating its sectors and solutions. We show that the model admits both BTZ-like black-hole solutions and homogeneous/inhomogeneous FRW cosmological solutions.We also investigate the global charges associated with the model and show that the algebra of charges is the extension of the Kac-Moody algebra for the field-rigid gauge charges, and the Virasoro algebrafor the diffeomorphism charges. Finally, we show that the model can be written as a generalized Chern-Simons theory, opening the perspective for its formulation as a generalized higher gauge theory.Comment: 40 page

Improved polymer solar cell performance by engineering of cathode interface

By engineering the interface between the intermediate photoactive layer and the cathode aluminum (Al) electrode, through the introduction of ultra-thin layers of various materials, in a standard\ud bulk heterojunction (BHJ) polymer solar cell (PSC) fabricated of regioregular poly(3-hexylthiophene)(rr-P3HT) and phenyl-C61-butyric acid methyl ester (PCBM), the power conversion efficiency (PCE) has\ud been effectively improved. The devices fabricated using individual single interlayer of bathocuproine (BCP), lithium fluoride (LiF) and Buckminster fullerene C60 have shown optimal efficiencies of ∼2.40%, ∼3.21% and ∼1.92% respectively. Further improvement of the photovoltaic efficiency was achieved by introducing a composite bilayer made of LiF in combination with BCP as well as with C60 at the BHJ/cathode interface. The best results were obtained by interposing a 9 nm of C60 interlayer in combination with a 0.9 nm\ud thick LiF layer, with the PCE of the PV cells being effectively increased up to 3.94% which represents an improvement of 23% as compared to the standard device with LiF interlayer alone. The photocurrent density (Jsc) versus voltage (V ) characteristic curves shows that the increase of the efficiency is essentially\ud due to an increase in Jsc. Moreover, all the sets of devices fabricated using various interlayers over a certain range of thickness exhibit an optimum PCE that is inversely proportional to the series resistance of the PV cells. We presume that interposing a C60/LiF layer at the interface could repair the poor contact at\ud the electron acceptor/cathode interface and improve the charge career extraction from the BHJ