Non local lagrangians(I): the pion

We define a family of non local and chirally symmetric low energy lagrangians motivated by theoretical studies on Quantum Chromodynamics. These models lead to quark propagators with non trivial momentum dependencies. We define the formalism for two body bound states and apply it to the pion. We study the coupling of the photon and W bosons with special attention to the implementation of local gauge invariance. We calculate the pion decay constant recovering the Goldberger-Treiman and the Gell-Mann-Oakes-Renner relations. We recover a form of the axial current consistent with PCAC. Finally we study the pion form factor and we construct the operators involved in its parton distribution.Comment: Latex, 25 pages with 15 figures; added references for introduction and section

Modulation Doping near Mott-Insulator Heterojunctions

We argue that interesting strongly correlated two-dimensional electron systems can be created by modulation doping near a heterojunction between Mott insulators. Because the dopant atoms are remote from the carrier system, the electronic system will be weakly disordered. We argue that the competition between different ordered states can be engineered by choosing appropriate values for the dopant density and the setback distance of the doping layer. In particular larger setback distances favor two-dimensional antiferromagnetism over ferromagnetism. We estimate some key properties of modulation-doped Mott insulator heterojunctions by combining insights from Hartree-Fock-Theory and Dynamical-Mean-Field-Theory descriptions and discuss potentially attractive material combinations.Comment: 9 pages, 9 figures, submitte

The eta-photon transition form factor

The eta-photon transition form factor is evaluated in a formalism based on a phenomenological description at low values of the photon virtuality, and a QCD-based description at high photon virtualities, matching at a scale $Q_{0}^{2}$. The high photon virtuality description makes use of a Distribution Amplitude calculated in the Nambu-Jona-Lasinio model with Pauli-Villars regularization at the matching scale $Q_{0}^{2}$, and QCD evolution from $Q_{0}^{2}$ to higher values of $Q^{2}$. A good description of the available data is obtained. The analysis indicates that the recent data from the BaBar collaboration on pion and eta transition form factor can be well reproduced, if a small contribution of twist three at the matching scale $Q_{0}^{2}$ is included.Comment: 14 pages, 3 figures, revised version, minor corrections, references added, conclusions unchanged. Accepted for publication in Phys. Rev.

Pion Parton Distributions in a non local Lagrangian

We use phenomenological nonlocal Lagrangians, which lead to non trivial forms for the quark propagator, to describe the pion. We define a procedure, based on the Dyson-Schwinger equations, for the calculation of the pion parton distributions at low Q^2. The obtained parton distributions fulfill all the wishful properties. Using a convolution approach we incorporate the composite character of the constituent quarks in the formalism. We evolve, using the Renormalization Group, the calculated parton distributions to the experimental scale and compare favorably with the data and draw conclusions.Comment: Latex, 11 pages with 6 figure

Model analysis of the world data on the pion transition form factor

We discuss the impact of recent Belle data on our description of the pion transition form factor based on the assumption that a perturbative formalism and a nonperturbative one can be matched in a physically acceptable manner at a certain hadronic scale $Q_{0}$. We discuss the implications of the different parameters of the model in comparing with world data and conclude that within experimental errors our description remains valid. Thus we can assert that the low $Q^2$ nonperturbative description together with an additional $1/Q^2$ term at the matching scale have a strong influence on the $Q^2$ behavior up to very high values of $Q^2$ .Comment: 6 pages and 3 figures. Contains a comparison with other models and additional reference

Flooding, channel dynamics and transverse infrastructure: a challenge for Middle Ebro river management

This study documents the impacts of engineering works on flood risk and channel dynamics of the maximum geomorphic flow reach of the Middle Ebro River (Spain) over the last ninety years. The map reveals how the construction of transversal transport lines and their ineffective design and maintenance has contributed to an elevated risk of flooding and channel avulsion at this location. In addition, the development of flood protection structures has restricted the natural dynamics of the river. These modifications have restricted the passage of flood waters, ultimately increasing flood hazards, by changing the area and depth of inundation and extending the flood hydrograph. The map allows for the interpretation of key processes, forecasting of flood hazards, and the evaluation of possible mitigating actions. These findings reconfirm that reducing space for the mobility of a river is not a good management solution and further aggravates the current situation

Polar surface engineering in ultra-thin MgO(111)/Ag(111) -- possibility of metal-insulator transition and magnetism

A recent report [Kiguchi {\it et al.}, Phys. Rev. B {\bf 68}, 115402 (2003)] that the (111) surface of 5 MgO layers grown epitaxially on Ag(111) becomes metallic to reduce the electric dipole moment raises a question of what will happen when we have fewer MgO layers. Here we have revealed, first experimentally with electron energy-loss spectroscopy, that MgO(111) remains metallic even when one-layer thick, and theoretically with the density functional theory that the metallization should depend on the nature of the substrate. We further show, with a spin-density functional calculation, that a ferromagnetic instability may be expected for thicker films.Comment: 5 pages, 7 figure

Strategies for cooperation emergence in distributed service discovery

This is an Accepted Manuscript of an article published by Taylor & Francis in Cybernetics and Systems on APR 3 2014], available online:http://www.tandfonline.com/10.1080/01969722.2014.894848[EN] In distributed environments where entities only have a partial view of the system, cooperation plays a key issue. In the case of decentralized service discovery in open agent societies, agents only know about the services they provide and who are their direct neighbors. Therefore, they need the cooperation of their neighbors in order to locate the required services. However, cooperation is not always present in open systems. Non-cooperative agents pursuing their own goals could refuse to forward queries from other agents to avoid the cost of this action; therefore, the efficiency of the decentralized service discovery could be seriously damaged. In this paper, we propose the ombination of incentives and local structural changes in order to promote cooperation in the service discovery process. The results show that, even in scenarios where the predominant behavior is not collaborative cooperation emerges.The work was partially supported by the Spanish Ministry of Science and Innovation through grants TIN2009-13839-C03-01, TIN2012-36586-C03-01, CSD2007-0022 (CONSOLIDER-INGENIO 2010).Del Val Noguera, E.; Rebollo Pedruelo, M.; Botti, V. (2014). Strategies for cooperation emergence in distributed service discovery. Cybernetics and Systems. 45(3):220-240. https://doi.org/10.1080/01969722.2014.894848S220240453Blanc , A. , Y.K. Liu , and A. Vahdat . “Designing Incentives for Peer-to-Peer Routing.” InProceedings of the 24th Annual Joint Conference of the IEEE Computer and Communications Societies, Vol. 1, pp. 374–385, 2005 .del Val , E. “Semantic Service Management in Service-Oriented Multi-Agent Systems.” Ph.D. thesis, Departament de Sistemes Informàtics i Computació, Universitat Politècnica de València, 2013 .Del Val, E., Rebollo, M., & Botti, V. (2012). Enhancing decentralized service discovery in open service-oriented multi-agent systems. Autonomous Agents and Multi-Agent Systems, 28(1), 1-30. doi:10.1007/s10458-012-9210-0DORAN, J. E., FRANKLIN, S., JENNINGS, N. R., & NORMAN, T. J. (1997). On cooperation in multi-agent systems. The Knowledge Engineering Review, 12(3), 309-314. doi:10.1017/s0269888997003111Eguíluz, V. M., Zimmermann, M. G., Cela‐Conde, C. J., & Miguel, M. S. (2005). Cooperation and the Emergence of Role Differentiation in the Dynamics of Social Networks. American Journal of Sociology, 110(4), 977-1008. doi:10.1086/428716Griffiths , N. and M. Luck . “Changing Neighbours: Improving Tag-Based Cooperation.” InProceedings of the 9th International Conference on Autonomous Agents and Multiagent Systems: volume 1.(AAMAS'10), 249–256. Richland, SC: International Foundation for Autonomous Agents and Multiagent Systems, 2010 .Gu , B. and S. Jarvenpaa . “Are Contributions to p2p Technical Forums Private or Public Goods? An Empirical Investigation.” Paper presented at the 1st Workshop on Economics of Peer-to-Peer Systems, June 4–5, 2004, Harvard University .Hauert, C., Traulsen, A., Brandt, H., Nowak, M. A., & Sigmund, K. (2007). Via Freedom to Coercion: The Emergence of Costly Punishment. Science, 316(5833), 1905-1907. doi:10.1126/science.1141588Hofmann , L.M. , N. Chakraborty , and K. Sycara . “The Evolution of Cooperation in Self-Interested Agent Societies: A Critical Study.” InProceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems, Volume 2 , edited by K. Tumer , P. Yolum , L. Sonenberg , and P. Stone , 685–692. IFAAMAS, 2011 .Lin, W. S., Zhao, H. V., & Liu, K. J. R. (2009). Incentive Cooperation Strategies for Peer-to-Peer Live Multimedia Streaming Social Networks. IEEE Transactions on Multimedia, 11(3), 396-412. doi:10.1109/tmm.2009.2012915Nowak, M. A. (2006). Five Rules for the Evolution of Cooperation. Science, 314(5805), 1560-1563. doi:10.1126/science.1133755Nowak, M. A., & Sigmund, K. (1998). Evolution of indirect reciprocity by image scoring. Nature, 393(6685), 573-577. doi:10.1038/31225Ohtsuki, H., Hauert, C., Lieberman, E., & Nowak, M. A. (2006). A simple rule for the evolution of cooperation on graphs and social networks. Nature, 441(7092), 502-505. doi:10.1038/nature04605Santos, F. C., Santos, M. D., & Pacheco, J. M. (2008). Social diversity promotes the emergence of cooperation in public goods games. Nature, 454(7201), 213-216. doi:10.1038/nature06940Shneidman , J. and D. C. Parkes . “Rationality and Self-Interest in Peer to Peer Networks.” Paper presented at the 2nd Int. Workshop on Peer-to-Peer Systems (IPTPS’03), February 20–21, 2003, Berkeley, CA .Sigmund, K. (2007). Punish or perish? Retaliation and collaboration among humans. Trends in Ecology & Evolution, 22(11), 593-600. doi:10.1016/j.tree.2007.06.012Sigmund, K. (2009). Sympathy and similarity: The evolutionary dynamics of cooperation. Proceedings of the National Academy of Sciences, 106(21), 8405-8406. doi:10.1073/pnas.0903947106Sigmund, K., Hauert, C., & Nowak, M. A. (2001). Reward and punishment. Proceedings of the National Academy of Sciences, 98(19), 10757-10762. doi:10.1073/pnas.161155698Sun , Q. and H. Garcia-Molina . “Slic: A Selfish Link-Based Incentive Mechanism for Unstructured Peer-To-Peer Networks.” Paper presented at the 24th International Conference on Distributed Computing Systems (ICDCS’04), March 23–26, 2004, Washington, DC .Villatoro , D. , J. Sabater-Mir , and S. Sen . “Social Instruments for Robust Convention Emergence.”Proceedings of the International Joint Conference on Artificial Intelligence, edited by T. Walsh, 420–425, 2011

Detection and nudge-intervention on sensitive information in social networks

[EN] Detecting sensitive information considering privacy is a relevant issue on Online Social Networks (OSNs). It is often difficult for users to manage the privacy associated with their posts on social networks taking into account all the possible consequences. The aim of this work is to provide information about the sensitivity of the content of a publication when a user is going to share it in OSN. For this purpose, we developed a privacy-assistant agent that detects sensitive information. Based on this information, the agent provides a message through a nudge mechanism warning about the possible risks of sharing the message. To avoid being annoying, the agent also considers the user's previous behaviour (e.g. if he previously ignored certain nudges) and adapts the messages it sends to give more relevance to those categories that are more important to the user from the point of view of the privacy risk. This agent was integrated into the social network Pesedia. We analysed the performance of different models to detect a set of sensitive categories (i.e. location, medical, drug/alcohol, emotion, personal attacks, stereotyping, family and association details, personal details and personally identifiable information) in a dataset of tweets in Spanish. The model that obtained the best results (i.e. F1 and accuracy) and that was finally integrated into the privacy-assistant agent was transformer-based.This work is supported by the Spanish Government project TIN2017-89156-R.Alemany, J.; Botti-Cebriá, V.; Del Val Noguera, E.; García-Fornes, A. (2022). Detection and nudge-intervention on sensitive information in social networks. Logic Journal of IGPL. 30(6):942-953. https://doi.org/10.1093/jigpal/jzac00494295330

Enhancing Smart-Home Environments using Magentix2

[EN] Multi-agent system paradigm has been envisioned as an appropriate solution for challenges in the area of smart-environments. Specifically, MAS add new capabilities such as adaption, reorganization, learning, coordination, etc. These features allow to deal with open issues in the context of smart-homes such as multi-occupancy, activity tracking or profiling activities and behaviors from multiple residents. In this paper, we present Magentix2 as a suitable MAS platform for the development of dynamic smart environments. Specifically, the use of Magentix2 (http://gti-ia.upv.es/sma/tools/magentix2/index.php) facilitates the management of the multiple occupancy in smart living spaces. Normative virtual organizations provide the possibility of defining a set of norms and organizational roles that facilitate the regulation and control of the actions that can be carried out by internal and external agents depending on their profile. Moreover, Magentix2 provides a tracing service to keep track of activities carried out in the system. We illustrate the applicability and benefits of Magentix2 in a set of scenarios in the context of smart-homes.This work is supported by the Spanish government grants PROMETEOII/2013/019,TIN2014-55206-R, TIN2015-65515-C4-1-R, H2020-ICT-2015-688095.Valero Cubas, S.; Del Val Noguera, E.; Alemany-Bordera, J.; Botti, V. (2017). Enhancing Smart-Home Environments using Magentix2. Journal of Applied Logic. 24:32-44. https://doi.org/10.1016/j.jal.2016.11.022S32442