Detection of Communities within the Multibody System Dynamics Network and Analysis of Their Relations

Multibody system dynamics is already a well developed branch of theoretical, computational and applied mechanics. Thousands of documents can be found in any of the well-known scientific databases. In this work it is demonstrated that multibody system dynamics is built of many thematic communities. Using the Elsevier’s abstract and citation database SCOPUS, a massive amount of data is collected and analyzed with the use of the open source visualization tool Gephi. The information is represented as a large set of nodes with connections to study their graphical distribution and explore geometry and symmetries. A randomized radial symmetry is found in the graphical representation of the collected information. Furthermore, the concept of modularity is used to demonstrate that community structures are present in the field of multibody system dynamics. In particular, twenty-four different thematic communities have been identified. The scientific production of each community is analyzed, which allows to predict its growing rate in the next years. The journals and conference proceedings mainly used by the authors belonging to the community as well as the cooperation between them by country are also analyzed

Photonic molecules for improving the optical response of macroporous silicon photonic crystals for gas sensing purposes

In this paper, we report the benefits of working with photonic molecules in macroporous silicon photonic crystals. In particular, we theoretically and experimentally demonstrate that the optical properties of a resonant peak produced by a single photonic atom of 2.6 µm wide can be sequentially improved if a second and a third cavity of the same length are introduced in the structure. As a consequence of that, the base of the peak is reduced from 500 nm to 100 nm, while its amplitude remains constant, increasing its Q-factor from its initial value of 25 up to 175. In addition, the bandgap is enlarged almost twice and the noise within it is mostly eliminated. In this study we also provide a way of reducing the amplitude of one or two peaks, depending whether we are in the two- or three-cavity case, by modifying the length of the involved photonic molecules so that the remainder can be used to measure gas by spectroscopic methods.Postprint (published version

Saying what cannot be said: The grace and the disgrace of a difficult joke

This article deals with the figure of the jester as the one who is allowed to say «what cannot be said». I rely on a current example: the controversy raised by a Comedy Central video in which comedian Rober Bodegas performed a stand-up routine centered on gypsies. This paper analyzes the aspects that could have provoked the flood of criticism that followed, from the subject of the jokes, the nature of its premises, its rhetoric or the comedian’s action itselfEn este artículo se aborda la figura del bufón como aquel a quien se le permite decir «lo que no se puede decir», aterrizando en un ejemplo actual: la polémica que suscitó un vídeo de Comedy Central en la que el cómico Rober Bodegas interpretaba una rutina de stand-up sobre gitanos. A lo largo del texto se analizan algunos aspectos que pudieron provocar el aluvión de críticas que suscitó el fragmento, desde el tema de los chistes, la naturaleza de sus premisas, su retórica o la propia actio del cómic

Study of resonant modes in a 700 nm pitch macroporous silicon photonic crystal

In this study the modes produced by a defect inserted in a macroporous silicon (MP) photonic crystal (PC) have been studied theoretical and experimentally. In particular, the transmitted and reflected spectra have been analyzed for variations in the defect’s length and width. The performed simulations show that the resonant frequency is more easily adjusted for the fabricated samples by length tuning rather than width. The optimum resonance peak results when centered in the PC bandgap. The changes in the defect geometry result in small variations of the optical response of the PC. The resonance frequency is most sensitive to length variations, while the mode linewidth shows greater change with the defect width variation. Several MPS photonic crystals were fabricated by the electrochemical etching (EE) process with optical response in the range of 5.8 µm to 6.5 µm. Results of the characterization are in good agreement with simulations. Further samples were fabricated consisting of ordered modulated pores with a pitch of 700 nm. This allowed to reduce the vertical periodicity and therefore to have the optical response in the range of 4.4 µm to 4.8 µm. To our knowledge, modes working in this range of wavelengths have not been previously reported in 3-d MPS structures. Experimental results match with simulations, showing a linear relationship between the defect’s length and working frequency inside the bandgap. We demonstrate the possibility of tailoring the resonance peak in both ranges of wavelengths, where the principal absorption lines of different gases in the mid infrared are placed. This makes these structures very promising for their application to compact gas sensors.Postprint (author's final draft

From Perturbation Theory to Confinement: How the String Tension is built up

We study the spatial volume dependence of electric flux energies for SU(2) Yang-Mills fields on the torus with twisted boundary conditions. The results approach smoothly the rotational invariant Confinement regime. The would-be string tension is very close to the infinite volume result already for volumes of $(1.2 \ {\rm fm.})^3$. We speculate on the consequences of our result for the Confinement mechanism.Comment: 6p, ps-file (uuencoded). Contribution to Lattice'93 Conference (Dallas, 1993). Preprint INLO-PUB 18/93, FTUAM-93/4

Formación crítica de documentalistas en medios de comunicación

Se centra el antiguo mito de la objetividad del discurso periodístico en la acción de uno de los actores más relevantes y desapercibidos de su proceso de construcción: el documentalista de medios de comunicación. Siendo un hecho la presencia subjetiva del documentalista en sus producciones, se opta por el reconocimiento y la explicitación de la misma mediante dos actuaciones: por un lado la revisión de las estrategias formativas de los documentalistas de medios en centros superiores públicos de modo que combinen la capacitación técnica con la capacitación crítica. Para ello se analizan las materias presentes en los planes de estudios responsables de su formación y se detectan los déficits localizados en función del objetivo buscado. Por otro, se proponen líneas de formación alternativa que puedan orientar a la incorporación transversal de la capacitación crítica de los documentalistas de medios en tales programas.This study takes the old myth of objectivity in media discourse to one of the most important but unrecognized actors in the process of its construction: the mass media information scientist or documentalist. Accepting the subjective presence of the documentalist in his/her productions, this article opts for the recognition and explicit statement of this role, recommending two actions. First, we suggest that public higher education institutions combine the technical training of mass media documentalists with training in critical thinking skills. Our study analysed the subjects covered in course syllabi to detect the deficiencies to be addressed in meeting this objective. Second, we propose alternative lines of training that can contribute to cross-training of mass media documentalists in those degree programs to ensure that they acquire the needed skills in critical analysi

Geografía, propaganda y turismo en la España de la postguerra: la Revista Geográfica Española

XII Coloquio de Geografía del Turismo, Ocio y Recreación de la Asociación de Geógrafos Españoles. Colmenarejo (Madrid), del 17 al 19 de junio de 2010.Este trabajo se ha realizado dentro del Proyecto de Investigación CS02008-03877, financiado por el Ministerio de Educación y el FEDER, en el cual colabora el primero de los autores

An integrated approach of learning, planning, and execution

Agents (hardware or software) that act autonomously in an environment have to be able to integrate three basic behaviors: planning, execution, and learning. This integration is mandatory when the agent has no knowledge about how its actions can affect the environment, how the environment reacts to its actions, or, when the agent does not receive as an explicit input, the goals it must achieve. Without an a priori theory, autonomous agents should be able to self-propose goals, set-up plans for achieving the goals according to previously learned models of the agent and the environment, and learn those models from past experiences of successful and failed executions of plans. Planning involves selecting a goal to reach and computing a set of actions that will allow the autonomous agent to achieve the goal. Execution deals with the interaction with the environment by application of planned actions, observation of resulting perceptions, and control of successful achievement of the goals. Learning is needed to predict the reactions of the environment to the agent actions, thus guiding the agent to achieve its goals more efficiently. In this context, most of the learning systems applied to problem solving have been used to learn control knowledge for guiding the search for a plan, but few systems have focused on the acquisition of planning operator descriptions. As an example, currently, one of the most used techniques for the integration of (a way of) planning, execution, and learning is reinforcement learning. However, they usually do not consider the representation of action descriptions, so they cannot reason in terms of goals and ways of achieving those goals. In this paper, we present an integrated architecture, lope, that learns operator definitions, plans using those operators, and executes the plans for modifying the acquired operators. The resulting system is domain-independent, and we have performed experiments in a robotic framework. The results clearly show that the integrated planning, learning, and executing system outperforms the basic planner in that domain.Publicad

Critical Organization of Knowledge in Mass Media Information Systems

This paper studies knowledge organization (KO) in media archives, focusing on the presence of subjectivity in the core tasks of mass media knowledge organizers (MKOS) dealing with press, radio and TV records, such as classification, representation, and any other process related to content analysis and organization in news information systems. Far from rejecting subjectivity and ideological bias in these operations - since they coparticipate in the media construction of reality—the authors consider MKOS to be genuine ideological and cultural mediators with the right and social responsibility to explicitly state the results of their “objectifiable” work (obtained through KO protocols and procedures determined by the media/company, classifications, thesauri, ontologies, etc.) and differentiate them from those of their political, ideological, cultural and, in sum, subjective stances. In order to achieve this, we propose the application of critical operators that should be followed by technical, collaborative and even technological actions geared to investing information systems with the capacity to consider those stances and allowing users to distinguish them. In short, it is the theoretical recognition of the subjective and biased presence of media knowledge organization operators in a job that is usually considered neutral, banal and even objective, and the initial development of tools for critical, self-critical, technical, and technological training keyed to its practical solution. This paper outlines the lines of work of a broader research study on the critical function of KO in the field of global media memory