Modeling flocks with perceptual agents from a dynamicist perspective

Computational simulations of flocks and crowds have typically been processed by a set of logic or syntactic rules. In recent decades, a new generation of systems has emerged from dynamicist approaches in which the agents and the environment are treated as a pair of dynamical systems coupled informationally and mechanically. Their spontaneous interactions allow them to achieve the desired behavior. The main proposition assumes that the agent does not need a full model or to make inferences before taking actions; rather, the information necessary for any action can be derived from the environment with simple computations and very little internal state. In this paper, we present a simulation framework in which the agents are endowed with a sensing device, an oscillator network as controller and actuators to interact with the environment. The perception device is designed as an optic array emulating the principles of the animal retina, which assimilates stimuli resembling optic flow to be captured from the environment. The controller modulates informational variables to action variables in a sensory-motor flow. Our approach is based on the Kuramoto model that describes mathematically a network of coupled phase oscillators and the use of evolutionary algorithms, which is proved to be capable of synthesizing minimal synchronization strategies based on the dynamical coupling between agents and environment. We carry out a comparative analysis with classical implementations taking into account several criteria. It is concluded that we should consider replacing the metaphor of symbolic information processing by that of sensory-motor coordination in problems of multi-agent organizations

Bichromatic laser emission from dipyrromethene dyes incorporated into solid polymeric media

9 pages, 9 figures.Bichromatic laser emission from dipyrromethene-based solid-state dye lasers is reported. The dependence of this dual emission on different factors and its origin and causes are discussed in the light of different models proposed in the literature. Our experimental results indicate that the long-wavelength emission can be explained in terms of reabsorption/reemission effects and inhomogeneous broadening of the S0-S1 transition. The short-wavelength emission corresponds to the usual S0-S1 transition and dominates at low dye concentration.This work was supported by Project Nos. MAT2004-04643-C03-01 and MAT2004-04643-C03-02 of the Spanish CICYT. One of the authors (M.Á.) thanks Ministerio de Ciencia y Tecnología (MCT) for a predoctoral grant. Another author (M.L.) thanks Comunidad Autónoma de Madrid for a postdoctoral grant and MCT for a Juan de la Cierva contract.Peer reviewe

Laughter and smiling facial expression modelling for the generation of virtual affective behavior

Laughter and smiling are significant facial expressions used in human to human communication. We present a computational model for the generation of facial expressions associated with laughter and smiling in order to facilitate the synthesis of such facial expressions in virtual characters. In addition, a new method to reproduce these types of laughter is proposed and validated using databases of generic and specific facial smile expressions. In particular, a proprietary database of laugh and smile expressions is also presented. This database lists the different types of classified and generated laughs presented in this work. The generated expressions are validated through a user study with 71 subjects, which concluded that the virtual character expressions built using the presented model are perceptually acceptable in quality and facial expression fidelity. Finally, for generalization purposes, an additional analysis shows that the results are independent of the type of virtual character’s appearance. © 2021 Mascaró et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Serious Games Network

[EN] “Serious games” can be defined as (digital) games used for purposes other than mere entertainment. Serious Games can be applied to a broad spectrum of areas, e.g. educational, healthcare, training in hazardous environments or situations. Game-based Learning, one aspect of Serious Games, are also more and more explored for all levels of education in different subjects, such as Ancient History. The SEGAN (SErious GAmes Network) will create a Community of Practice on the Serious Games subject. The main objective is to create a stable (but expanding) consortium to exchange ideas and experiences related to Serious Games. The SEGAN Network invites the people of the community of Archaeology, Cultural Heritage and Ancient History interested in Serious Games to join the net and to participate in their activities.[ES] Los “juegos serios" se podrían definir como aquellos juegos (digitales) utilizados para fines distintos del mero entretenimiento. El concepto de “juegos serios” se puede aplicar a un amplio espectro de áreas, por ejemplo la educación, la sanidad, la formación en entornos o situaciones peligrosas. Los juegos de aprendizaje también son cada vez más utilizados en todos los niveles de la educación y en prácticamente todos los temas, como por ejemplo la Historia Antigua. La red SEGAN (SErious GAmes Network) va a crear una comunidad de trabajo sobre el tema de los “juegos serios". El objetivo principal es crear un consorcio estable -pero en expansión- para intercambiar ideas y experiencias relacionadas con los Juegos Serios. La Red SEGAN invita a las personas de la comunidad de Arqueología, Patrimonio Cultural y la Historia Antigua interesado en juegos serios a unirse a la red y participar en sus actividades.This paper has been partly funded by the project “Serious Games Project – SEGAN”, no. 519332- LLP-1-2011-1-PT-KA3-KA3NW. Lifelong Learning. Education, Audiovisual and Culture Agency of the European Union. This paper has been funded by the project “Replikants: Towards a New Generation of Human‐like Agents”, TIN2011‐24660, S. G. P. I., Ministerio Ciencia e Innovación (Spain)Vaz De Carvalho, C.; Latorre Andrés, PM.; Serón Arbeloa, FJ. (2013). Serious Games Network. Virtual Archaeology Review. 4(9):174-180. https://doi.org/10.4995/var.2013.4271OJS17418049ANDERSON, Eike Falk et al. (2010): "Developing Serious Games for Cultural Heritage: A State-ofthe- Art Review", Virtual Reality 14(4), Springer, pp. 255-275.FRANSSILA, H. & PEHKONNEN, M. (2005): "Why do ICT-Strategy implementation in schools fail and ICT-Practices do no develop?", in Media Skills and Competence Conference Proceedings. Tampere, Finland, pp. 9-16.HOUTHOFF BURUMA - The Game. http://www.ranj.com/content/werk/houthoff-buruma-thegameHUSSAIN, T.S. & FERGUSON, W. (2005): "Efficient development of large-scale military training environments using a multi-player game", in Proceedings of the 2005 Fall Simulation Interoperability Workshop, pp. 421-431. Orlando, FL, September.IBM Service Management Virtual Simulator http://www-01.ibm.com/software/tivoli/features/smsimulator/The Novicraft HRD game http://www.teamingstream.com/The SEGAN project http://seriousgamesnet.euMOLONEY, J. & AMOR, R.: "StringCVE: Advances in a Game Engine-Based Collaborative Virtual Environment for Architectural Design", in Proceedings of the International Conference on Applications of Virtual Reality, Blacksburg, 2003, September 156-168, pp. 24-26.SUSI, Tarja (2007): "Serious Games - An Overview", Technical Report HS- IKI -TR-07-001. School of Humanities and Informatics. University of Skövde, Sweden.The TIMEMESH Game http://timemesh.eu/WALLIN, E. (2005): "The Rise and Fall of Swedish Educational Technology1960-1980", in Scandinavian Journal of Educational Research, 5, pp. 437-460

Photophysical and laser emission studies of 8-polyphenylene-substituted BODIPY dyes in liquid solution and in solid polymeric matrices

In our search for efficient and photostable laser dyes, four new dyes with the basic structure of the commercial BODIPY laser dye PM567, with either an 8-diphenylene or an 8-p-triphenylene group, both substituted at the terminal polyphenylene position with an acetoxymethyl (dyes P2Ar1Ac and P3Ar1Ac, respectively) or a methacryloyloxymethyl group (dyes P2Ar1MA and P3Ar1MA, respectively), have been synthesized. The photophysical and lasing properties of the dyes have been studied both dissolved in liquid solvents (acetoxymethyl dyes) and incorporated into solid polymeric matrices, in the latter case as solutions (acetoxymethyl dyes) or as copolymers with methyl methacrylate (methacryloyloxymethyl dyes). In liquid solution, the photophysics of P2Ar1Ac and P3Ar1Ac is scarcely affected by the number (two or three) of p-phenylene units. Quantum mechanical calculations reveal that the p-phenylene units in these dyes are twisted ca. 37◦ each other, an that the first 8-p-phenylene group stands nearly perpendicular to the aromatic BODIPY plane, resulting in electronic decoupling of the two chromophores. P2Ar1Ac exhibits a somewhat lower photodegradation quantum yield under UV and visible irradiation, if compared with P3Ar1Ac or with PM567, likely because of its also lower rate constant for the reaction with in situ-generated singlet molecular oxygen. Both acetoxymethyl dyes emit laser radiation in solution in all the solvents tried, under transversal pumping at 532 nm. In ethyl acetate, with a dye concentration of 0.80 × 10−3 M, laser efficiencies as high as 80% have been observed. When the 8-polyphenylene dyes were incorporated into solid poly(methyl methacrylate) (PMMA) matrices, as solutions or as copolymers, the fluorescence emission increased with respect to that of the parent PM567 dye dissolved in the same matrix, and lasing efficiencies in the range 18–31% were obtained, with good photostability. The dye P2Ar1Ac dissolved in PMMA was found to exhibit the best overall laser behavior, with a good balance between efficiency and photostability.This work was supported by Project MAT2004-04643-C03-01 of the Spanish CICYT. M. Liras thanks Comunidad Aut´onoma de Madrid for a predoctoral scholarship and Ministerio de Educaci´on y Ciencia for a Juan de la Cierva contract.M. A´ lvarez thanks Ministerio de Educaci´on y Ciencia for a predoctoral scholarship. The 8-polyphenylene-substituted boron-dipyrromethene dyes described in this paper and their utilization in liquid and solidstate dye lasers are covered by Spanish PatentNo. P200701763 filed on 25 June 2007.Peer reviewe

Proyecto esar. Trabajo colaborativo en red para la formación del profesorado

Uno de los retos que plantea la sociedad del conocimiento consiste en avanzar en una cultura educativa de la colaboración. La educación y la formación del profesorado también deben impulsar esta cultura y formar a los estudiantes para que desarrollen las capacidades necesarias para su integración en un mundo que está experimentando grandes cambios. La globalización implica, también, que las tareas y los proyectos necesariamente se ven afectados por la complejidad y requieren de la interacción y el intercambio entre personas del mundo entero. En este contexto, los agentes que intervienen o van a intervenir en un futuro en proyectos de investigación, de desarrollo y de innovación, deberán formar parte de redes sociales donde la colaboración es imprescindible. El proyecto ESAR pretende analizar los problemas que surgen al intentar asumir esta nueva cultura

The progamic phase of an early-divergent angiosperm, Annona cherimola (Annonaceae)

33 Pag. The definitive version, with the figures, is available at: http://aob.oxfordjournals.org/Background and Aims: Recent studies of reproductive biology in ancient angiosperm lineages are beginning to shed light on the early evolution of flowering plants, but comparative studies are restricted by fragmented and meagre species representation in these angiosperm clades. In the present study, the progamic phase, from pollination to fertilization, is characterized in Annona cherimola, which is a member of the Annonaceae, the largest extant family among early-divergent angiosperms. Beside interest due to its phylogenetic position, this species is also an ancient crop with a clear niche for expansion in subtropical climates. Methods: The kinetics of the reproductive process was established following controlled pollinations and sequential fixation. Gynoecium anatomy, pollen tube pathway, embryo sac and early post-fertilization events were characterized histochemically. Key Results: A plesiomorphic gynoecium with a semi-open carpel shows a continuous secretory papillar surface along the carpel margins, which run from the stigma down to the obturator in the ovary. The pollen grains germinate in the stigma and compete in the stigma-style interface to reach the narrow secretory area that lines the margins of the semi-open stylar canal and is able to host just one to three pollen tubes. The embryo sac has eight nuclei and is well provisioned with large starch grains that are used during early cellular endosperm development. Conclusions: A plesiomorphic simple gynoecium hosts a simple pollen–pistil interaction, based on a support–control system of pollen tube growth. Support is provided through basipetal secretory activity in the cells that line the pollen tube pathway. Spatial constraints, favouring pollen tube competition, are mediated by a dramatic reduction in the secretory surface available for pollen tube growth at the stigma–style interface. This extramural pollen tube competition contrasts with the intrastylar competition predominant in more recently derived lineages of angiosperms.This work was supported by the Spanish Ministry of Education (Project Grants AGL2004-02290/AGR, AGL2006-13529 and AGL2007-60130/AGR), GIC-Aragón 43, Junta de Andalucía (AGR2742), and the European Union under the INCO-DEV program (Contract 015100). J.L. was supported by a grant from Junta de Andalucía.Peer reviewe