A P-Lingua Programming Environment for Membrane Computing

A new programming language for membrane computing, PLingua, is developed in this paper. This language is not designed for a speci c simulator software. On the contrary, its purpose is to o er a general syntactic framework that could de ne a uni ed standard for membrane computing, covering a broad variety of models. At the present stage, P-Lingua can only handle P systems with active membranes, although the authors intend to extend it to other models in the near future. P-Lingua allows to write programs in a friendly way, as its syntax is very close to standard scienti c notation, and parameterized expressions can be used as shorthand for sets of rules. There is a built-in compiler that parses these human-style programs and generates XML documents that can be given as input to simulation tools, di erent plugins can be designed to produce speci c adequate outputs for existing simulators. Furthermore, we present in this paper an integrated development environment that plays the role of interface where P-lingua programs can be written and compiled. We also present a simulator for the class of recognizer P systems with active membranes, and we illustrate it by following the writing, compiling and simulating processes with a family of P systems solving the SAT problem.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC-58

A Computational Complexity Theory in Membrane Computing

In this paper, a computational complexity theory within the framework of Membrane Computing is introduced. Polynomial complexity classes associated with di erent models of cell-like and tissue-like membrane systems are de ned and the most relevant results obtained so far are presented. Many attractive characterizations of P 6= NP conjecture within the framework of a bio-inspired and non-conventional computing model are deduced.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía P08–TIC-0420

Modelo tectónico reciente de la Cuenca Alta del Tajo (parte central española)

Active tectonics within the Upper Tagus Basin is related to the lithospheric flexure affecting the Palaeozoic basement of the basin. This flexure displays NE-SW trending. Besides, this structure is in agreement with the regional active stress field defined by the maximum horizontal stress with NW-SE trending. In this tectonic framework, irregular clusters of instrumental seismicity (Mw< 5.0) fade in the zone bounded by the Tagus River and the Jarama River valleys. These clusters are related to major NW-SE trending faults of suspected strike-slip kinematics. Moreover, reverse faults with NE-SW trending are affected by the strike-slip system as well. Despite the reverse faults are in agreement with the present SHMAX orientation, though, they apparently are blocked as seismogenic sources (scarce instrumental seismicity recorded today). In addition, we have determined the regional and local stress/ strain fields and two different fracture patterns were observed. Hence, we have divided the area in two zones: (1) the lateral bands of the basin, defined by reverse faulting (NE-SW trending) and strike-slip faulting (NW-SE trending) and (2) the central zone of the basin characterized by shallow normal faulting and NE-SW trending strike-slip faults. Furthermore, surface faulting and liquefaction structures are described affecting Middle to Late Pleistocene fluvial deposits, suggesting intrabasinal palaeoseismic activity (5.5 < M < 6.5) during the Late Quaternary. The obtained structural and tectonic information has been used to classify and characterize the Upper Tagus Basin as a semi-stable intraplate seismogenic zone, featured by Pleistocene slip-rates < 0.02 mm/yr. This value is low but it affords the occurrence of Pleistocene paleoearthquakes.La tectónica activa de la Cuenca Alta del río Tajo está caracterizada por la presencia de una flexión litosférica localizada en el basamento paleozoico, y cuyo eje se orienta según NE-SW. Esta flexión es coherente con el estado de esfuerzos actual en la zona, definido mediante la orientación del esfuerzo máximo horizontal, SHMAX, según NW-SE. En este contexto, la sismicidad en el borde sur del Sistema Central aparece concentrada en fallas direccionales según NW-SE, registrándose terremotos de magnitud < 5.0 (S. XX). Estos desgarres sectorizan el sistema de fallas inversas (NE-SW) que estructuran la cadena montañosa, las cuales a pesar de estar orientados coherentemente con el estado actual de esfuerzos, aparecen bloqueados o desactivados como fuentes sismogénicas. La geometría de la flexura condiciona la ocurrencia de una zona de concentración anómala de esfuerzos que resulta en la agrupación de eventos sísmicos localizada entre los valles de los ríos Tajo y Jarama. El estudio sismotectónico indica que el campo actual de deformación se encuentra distribuido en dos zonas relacionadas con la flexión: (1) una zona central caracterizada por la presencia de fallas normales superficiales y desgarres orientados según NE-SW; y (2) zona lateral caracterizada por fallas de tipo inverso (NE-SW) y desgarres (NW-SE) y que bordea a la zona anterior. Estudios paleosísmicos en la zona muestran la ocurrencia de diferentes niveles de liquefacción afectando a los depósitos fluviales del Pleistoceno Medio y Superior en los valles de los ríos Manzanares, Jarama y Tajo, así como una importante variedad de estructuras de deformación. En general la granulometría licuefactada muestra diques de arena, aunque en algún caso aparecen niveles decimétricos de gravas. A partir de los datos sismotectónicos, geológicos y paleosísmicos descritos y recopilados para esta zona, la Cuenca alta del Tajo puede clasificarse como una zona sismogénica intraplaca con velocidades de deformación pleistocenas inferiores a 0,02 mm/año y sismicidad instrumental difusa de tamaño moderado-bajo

Pyrogenic organic matter from palaeo-fires during the Holocene: A case study in a sequence of buried soils at the Central Ebro Basin (NE Spain)

We studied the fire record and its environmental consequences during the Holocene in the Central Ebro Basin. This region is very sensitive to environmental changes due to its semiarid conditions, lithological features and a continuous human presence during the past 6000 years. The study area is a 6 m buried sequence of polycyclic soils developed approximately 9500 years ago that is exceptionally well preserved and encompasses four sedimentary units. The content and size distribution of macroscopic charcoal fragments were determined throughout the soil sequence and the analysis of the composition of charcoal, litter and sediments via analytical pyrolysis (Py-GC/MS). The high amount of charcoal fragments recovered in most horizons highlights the fire frequencies since the beginning of the Neolithic, most of which were probably of anthropogenic origin. In some soil horizons where charcoal was not found, we detected a distribution pattern of lipid compounds that could be related to biomass burning. On the other hand, the low number of pyrolysates in the charcoal could be attributed to high-intensity fires. No clear pattern was found in the composition of pyrolysates related to the age of sediments or vegetation type. The most ancient soil (Unit 1) was the richest in charcoal content and contains a higher proportion of larger fragments (>4 mm), which is consistent with the burning of a relatively dense vegetation cover. This buried soil has been preserved in situ, probably due to the accumulation of sedimentary materials because of a high-intensity fire. In addition, the pyrogenic C in this soil has some plant markers that could indicate a low degree of transformation. In Units 2–4, both the amount of charcoals and the proportions of macrofragments >4 mm are lower than those in Unit 1, which coincides with a more open forest and the presence of shrubs and herbs. The preservation of this site is key to continuing with studies that contribute to a better assessment of the consequences of future disturbances, such as landscape transformation and climate change

Track trajectories with model uncertainty using a robust differentiator

[EN] In this article, we present the Levant’s Robust Differentiator applied to robot manipulators whose objective is to follow a desired trajectory. The robots’ dynamic model is unknown. The velocity obtained using the Robust Differentiator is applied in the control structure in order to fulfill the tracking task. A comparative study is made between the Levant’s Robust Differentiator and the most-used techniques to calculate the velocity. Experimental results are presented.[ES] En este artículo se presenta el uso de un diferenciador robusto de Levant aplicado a robots manipuladores cuyo objetivo es realizar el seguimiento de una trayectoria deseada. El modelo dinámico de los robots es desconocido. La velocidad obtenida empleando el diferenciador robusto se aplica en la estructura de control con la finalidad de cumplir con la tarea de seguimiento. Se realiza un estudio comparativo entre el diferenciador robusto de Levant y las técnicas más usadas para calcular la velocidad. Son presentados resultados experimentales.Los autores agradecen a PRODEP (PROMEP) con el número de Folio BUAP–811 y los proyectos PAPIIT 116314 y 114617 por el apoyo recibido, a CONACYT por la Cátedra CONACYT–CICESE 2017 y al Laboratorio de Robótica de la Facultad de Ciencias de la Electrónica de la Benemérita Universidad Autónoma de Puebla.Sánchez-Sánchez, P.; Gutiérrez–giles, A.; Pliego–jiménez, J.; Arteaga–pérez, M. (2019). Seguimiento de trayectorias con incertidumbre del modelo usando un diferenciador robusto. Revista Iberoamericana de Automática e Informática. 16(4):423-434. https://doi.org/10.4995/riai.2019.10265SWORD423434164Alcocer, A. and Robertsson, A. and Valera, A. and Johansson, R., 2003. Force Estimation and Control in Robot Manipulators. Proceedings of 7th Symposium on Robot Control (SYROCO'03) 55-60. Wroclaw, Poland https://doi.org/10.1016/S1474-6670(17)33369-4Atassi, A. N. and Khalil, H. K., 2000. Separation results for the stabilization of nonlinear systems using di_erent high-gain observer designs. Systems and Control Letters, 39(15), 183-191. https://doi.org/10.1016/S0167-6911(99)00085-7Berghuis, H. and Nijmeijer, H., 1994. Robust control of robots via linear estimated state feedback. IEEE Transactions on Automatic Control, 39(10), 2159-2162.https://doi.org/10.1109/9.328807Calafiore, G. and Indri, M. and Bona, B., 1997. Robot dynamic calibration: Optimal excitation trajectories and experimental parameter estimation. Journal of Robotic Systems 18(2), 55-68. https://doi.org/10.1002/1097-4563(200102)18:23.3.CO;2-FCruz-Zavala, E. and Moreno, J. A. and Fridman, L. M., 2010. Diferenciador Robusto Exacto y Uniforme. Proceedings of AMCA 2010, 1-6.Dabroom, A. M. and Khalil, H. K., 1994. Numerical differentiation using high gain observers. Proceedings of of the IEEE Conference on Decision and Control, 4790-4795. https://doi.org/10.1109/CDC.1997.649776Diop, S. and Grizzle, J. and Moraal, P. and Stefanopoulou, A., 1994. Interpolation and numerical differentiation for observer design. Proceedings of the American Control Conference, 1329-1333. https://doi.org/10.1109/ACC.1994.752275Hacksel, P. J. and Salcudean, S. E., 1994. Estimation of Environment Forces and Rigid-Body Velocities using Observers. Proc. IEEE International Conference on Robotics and Automation, 931-936. San Diego, CA, USA https://doi.org/10.1109/ROBOT.1994.351233Kelly, R. and Ortega, R. and Ailon, A. and Loria, A., 1994. Global regulation of flexible joint robots using approximate differentiation. IEEE Transactions on Automatic Control 39(6), 1222-1224. https://doi.org/10.1109/9.293181Kelly, R. and Santibáñez, V., 2003. Control de Movimiento de Robots Manipuladores. Prentice-HallKhalil, H. K., 1996. Nonlinear Systems. Prentice-HallKhatib, O., 1987. A Unified Approach for Motion and Force Control of Robot Manipulators: The Operational Space Formulation. IEEE Journal of Robotics and Automation 3(1), 43-53. https://doi.org/10.1109/JRA.1987.1087068Kumar, B. and Dutta-Roy, S. C., 1988. Design of digital differentiators for low frequencies. Proceedings of the IEEE, 76(3), 287-289. https://doi.org/10.1109/5.4408Levant, A., 1998. Sliding order and sliding accuracy in sliding mode control. International Journal of Control, 58(6), 1247-1263. https://doi.org/10.1080/00207179308923053Levant, A., 1998. Robust exact diferentiation via sliding mode technique. Automatica, 34(3), 379-384. https://doi.org/10.1016/S0005-1098(97)00209-4Levant, A., 2003. Higher-order sliding modes, diferentiation and output-feedback control. International Journal of Control, 76(9), 924-941. https://doi.org/10.1080/0020717031000099029Loria, A., 2016. Observers are Unnecessary for Output-Feedback Control of Lagrangian Systems. IEEE Transactions on Automatic Control, 61(4), 905- 920. https://doi.org/10.1109/TAC.2015.2446831Martínez-Rosas, J. C. and Arteaga-Pérez, M. A. and Castillo-Sánchez, A., 2006. Decentralized Control of Cooperative Robots without Velocity-Force Measurements. Automatica 42, 329-336. https://doi.org/10.1016/j.automatica.2005.10.007Martínez-Rosas, J. C. and Arteaga-Pérez, M. A., 2008. Force and Velocity Observers for the Control of Cooperative Robots. Robotica 26, 85-92. https://doi.org/10.1017/S026357470700361XMoreno, J. and Kelly, R., 2002. On motor velocity control by using only position measurements: two case studies. International Journal of Electrical Engineering Education 39(2), 118-127. https://doi.org/10.7227/IJEEE.39.2.4Nicosia, S. and Tornambe, A. and Valigi, P., 1990. Experimental results in state estimation of industrial robots. Proceedings of 29th IEEE Conference on Decision and Control, 360-365. https://doi.org/10.1109/CDC.1990.203613Parsa, K. and Aghili, F., 2006. Adaptive Observer for the Calibration of the Force-Moment Sensor of a Space Robot. Proceedings of the 2006 IEEE International Conference on Robotics and Automation, 1667-1673. Orlando, Florida. https://doi.org/10.1109/ROBOT.2006.1641946Rabiner, L. R. and Steiglitz, K., 1970. The design of wide-band recursive and nonrecursive digital differentiators. IEEE Transactions on Audio and Electroacoustics, 18(2), 204-209. https://doi.org/10.1109/TAU.1970.1162090Radkhah, K. and Kulic, D. and Croft, E., 2007. Dynamic parameter identification for the CRS A460 robot. Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, 1-6. San Diego, CA, USA. https://doi.org/10.1109/IROS.2007.4399314Sira-Ramírez, H., 2005. Control de sistemas no lineales linealización aproximada, extendida, exacta. Pearson Prentice-HallStotsky, A. and Hedrick, J. K. and Yip, P. P., 1994. The use of sliding modes to simplify the backstepping control method. Proceedings of the American Control Conference, 1703-1708. https://doi.org/10.1109/ACC.1997.610875Stotsky, A. and Kolmanovsky, I., 2001. Simple Unknown Input Estimation Techniques for Automotive Applications. Proceedings of the American Control Conference, 3312-3317. Arlington, VA, USA. https://doi.org/10.1109/ACC.2001.946139Swevers, J. and Ganseman, C. and Tukel, D. B. and de-Schutter, J. and Van-Brussel, H., 1997. Optimal robot excitation and identification. IEEE Transactions on Robotics and Automation 13(5), 730-740. https://doi.org/10.1109/70.63123

Membrane dissolution and division in P

Membrane systems with dividing and dissolving membranes are known to solve PSPACE problems in polynomial time. However, we give a P upperbound on an important restriction of such systems. In particular we examine systems with dissolution, elementary division and where each membrane initially has at most one child membrane. Even though such systems may create exponentially many membranes, each with di erent contents, we show that their power is upperbounded by PJunta de Andalucía TIC-581Ministerio de Educación y Ciencia TIN2006-1342

Do tunneling states and boson peak persist or disappear in extremely stabilized glasses?

We review and concurrently discuss two recent works conducted by us, which apparently give opposite results. Specifically, we have investigated how extreme thermal histories in glasses can affect their universal properties at low temperatures, by studying: (i) amber, the fossilized natural resin, which is a glass which has experienced a hyperaging process for about one hundred million years; and (ii) ultrastable thin-film glasses of indomethacin. Specific heat Cp measurements in the temperature range 0.07 K < T < 30 K showed that the amount of two-level systems, assessed from the linear term at the lowest temperatures, was exactly the same for the pristine hyperaged amber glass as for the subsequently rejuvenated samples, whereas just a modest increase of the boson-peak height (in Cp/T³) with increasing rejuvenation was observed, related to a corresponding increase of the Debye coefficient. On the other hand, we have observed an unexpected suppression of the two-level systems in the ultrastable glass of indomethacin, whereas conventionally prepared thin films of the same material exhibit the usual linear term in the specific heat below 1 K ascribed to these universal two-level systems in glasses. By comparing both highly-stable kinds of glass, we conclude that the disappearance of the tunneling two-level systems in ultrastable thin films of indomethacin may be due to the quasi-2D and anisotropic behavior of this glass, what could support the idea of a phonon-mediated interaction between two-level systems

Frozen ground and snow cover monitoring in Livingston and Deception islands, Antarctica: preliminary results of the 2015-2019 PERMASNOW project

Since 2006, our research team has been establishing in the islands of Livingston and Deception, (South Shetland archipelago, Antarctica) several monitoring stations of the active layer thickness within the international network Circumpolar Active Layer Monitoring (CALM), and the ground thermal regime for the Ground Terrestrial Network-Permafrost (GTN-P). Both networks were developed within the International Permafrost Association (IPA). In the GTN-P stations, in addition to the temperature of the air, soil, and terrain at different depths, the snow thickness is also monitored by snow poles. Since 2006, a delay in the disappearance of the snow layer has been observed, which could explain the variations we observed in the active layer thickness and permafrost temperatures. Therefore, in late 2015 our research group started the PERMASNOW project (2015-2019) to pay attention to the effect of snow cover on ground thermal This project had two different ways to study the snow cover. On the first hand, in early 2017 we deployed new instrumentation, including new time lapse cameras, snow poles with high number of sensors and a complete and complex set of instruments and sensors to configure a snow pack analyzer station providing 32 environmental and snow parameters. We used the data acquired along 2017 and 2018 years with the new instruments, together with the available from all our already existing sensors, to study in detail the snow cover. On the other hand, remote sensing data were used to try to map the snow cover, not only at our monitoring stations but the entire islands in order to map and study the snow cover distribution, as well as to start the way for future permafrost mapping in the entire islands. MODIS-derived surface temperatures and albedo products were used to detect the snow cover and to test the surface temperature. Since cloud presence limited the acquisition of valid observations of MODIS sensor, we also analyzed Terrasar X data to overcome this limitation. Remote sensing data validation required the acquirement of in situ ground-true data, consisting on data from our permanent instruments, as well as ad hoc measurements in the field (snow cover mapping, snow pits, albedo characterization, etc.). Although the project is finished, the data analysis is still ongoing. We present here the different research tasks we are developing as well as the most important results we already obtained about the snow cover. These results confirm how the snow cover duration has been changing in the last years, affecting the ground thermal behavior.info:eu-repo/semantics/publishedVersio

3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measure- ments (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discre- tization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.Ministerio de Ciencia y Tecnología SAF2011- 27116; IPT-2011-1480-900000