A Full Non-Monotonic Transition System for Unrestricted Non-Projective Parsing

Restricted non-monotonicity has been shown beneficial for the projective arc-eager dependency parser in previous research, as posterior decisions can repair mistakes made in previous states due to the lack of information. In this paper, we propose a novel, fully non-monotonic transition system based on the non-projective Covington algorithm. As a non-monotonic system requires exploration of erroneous actions during the training process, we develop several non-monotonic variants of the recently defined dynamic oracle for the Covington parser, based on tight approximations of the loss. Experiments on datasets from the CoNLL-X and CoNLL-XI shared tasks show that a non-monotonic dynamic oracle outperforms the monotonic version in the majority of languages.Comment: 11 pages. Accepted for publication at ACL 201

Conservation of orbital angular momentum in crystals with a random domain distribution of nonlinearity in SHG

En col·laboració amb la Universitat Autònoma de Barcelona (UAB) i la Universitat de Barcelona (UB)In this master thesis we build an experimental setup for studying the conservation of the orbital angular momentum (OAM) of light in second harmonic generation (SHG) in Strontium Barium Niobate (SBN) crystals with random distribution of domains with inverted nonlinearity. Different methods to generate and measure OAM were implemented and the OAM conservation in SHG process in different kind of nonlinear crystals was studied. The experimental results point to the macroscopic non-conservation of the OAM in the family of nonlinear random crystals in SHG process

Madrid, ciudad clandestina

Al finalizar la Guerra Civil, el Partido Comunista de España tuvo que hacer frente a una nueva organización en el exilio, pero asimismo permanecieron antiguos militantes y simpatizantes dentro de la península. Éstos últimos fueron quienes protagonizaron los primeros intentos de resistencia y oposición en el interior del país contra el nuevo régimen. Las dificultades no fueron empero pocas, procedentes tanto de la presión policial como de la descoordinación y rivalidades internas