242 research outputs found
Exploring Conditional Rewriting Logic Computations
[EN] Trace exploration is concerned with techniques that allow computation
traces to be dynamically searched for specific contents.
Depending on whether the exploration is carried backward or forward,
trace exploration techniques allow provenance tracking or impact
tracking to be done. The aim of provenance tracking is to show
how (parts of) a program output depends on (parts of) its input
and to help estimate which input data need to be modified to accomplish
a change in the outcome. The aim of impact tracking is
to identify the scope and potential consequences of changing the
program input. Rewriting Logic (RWL) is a logic of change that supplements
(an extension of) the equational logic by adding rewrite
rules that are used to describe (nondeterministic) transitions between
states. In this paper, we present a rich and highly dynamic,
parameterized technique for the forward inspection of RWL computations
that allows the nondeterministic execution of a given
conditional rewrite theory to be followed up in different ways. With
this technique, an analyst can browse, slice, filter, or search the
traces as they come to life during the program execution. The navigation
of the trace is driven by a user-defined, inspection criterion
that specifies the required exploration mode. By selecting different
inspection criteria, one can automatically derive a family of practical
algorithms such as program steppers and more sophisticatedThis work has been partially supported by the EU (FEDER) and the Spanish MEC project Ref. TIN2010-21062-C02-02, the Spanish MICINN complementary action Ref. TIN2009-07495-E, and by Generalitat Valenciana Ref. PROMETEO2011/052. This work was carried out during the tenure of D. Ballis' ERCIM "Alain Bensoussan" Postdoctoral Fellowship. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement N. 246016. F. Frechina was supported by FPU-ME grant AP2010-5681, and J. Sapina was supported by FPI-UPV grant SP2013-0083.Alpuente Frasnedo, M.; Ballis, D.; Frechina Navarro, F.; Sapiña Sanchis, J. (2015). Exploring Conditional Rewriting Logic Computations. Journal of Symbolic Computation. 69:3-39. https://doi.org/10.1016/j.jsc.2014.09.028S3396
Translating between Alloy specifications and UML class diagrams annotated with OCL
Model-driven engineering (MDE) is a software engineering approach based on model transformations at different abstraction levels. It prescribes the development of software by successively transforming the models from abstract (specifications) to more concrete ones (code). Alloy is an increasingly popular lightweight formal specification language that supports automatic verification. Unfortunately, its widespread industrial adoption is hampered by the lack of an ecosystem of MDE tools, namely code generators. This paper presents a model transformation from Alloy to UML class diagrams annotated with OCL (UML+OCL) and shows how an existing transformation from UML+OCL to Alloy can be improved to handle dynamic issues. The proposed bidirectional transformation enables a smooth integration of Alloy in the current MDE contexts, by allowing UML+OCL specifications to be transformed to Alloy for validation and verification, to correct and possibly refine them inside Alloy, and to translate them back to UML+OCL for sharing with stakeholders or to reuse current model-driven architecture tools to refine them toward code.This work was funded by European Regional Development Fund (ERDF) through the COMPETE Programme (operational program for competitiveness) and by national funds through the FCT (Fundaaco para a Ciencia e a Tecnologia-portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-020532. Part of the work was done while the first author was visiting the Software Design Group at CSAIL, MIT, USA, funded by FCT sabbatical grant SFRH/BSAB/1187/2011. The second author was also partially supported by QREN (the portuguese National Strategy Reference Chart) project 1621, while visiting the High-Assurance Software Laboratory at Universidade do Minho, Portugal. Finally, we would also like to thank all anonymous reviewers for the valuable comments and suggestions
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Adhesión de las mujeres embarazadas a los ejercicios para fortalecer el suelo pélvico
Objective: To analyse the adherence of pregnant women to pelvic floor muscle exercises (PFME) during pregnancy.
Methods: Prospective study, with 315 pregnant women; data collection was performed by phone and face-to-face; data analysis was descriptive and inferential with 5% significance level.
Results: In the first half of pregnancy, the total adherence was 36.5%; when gathered total adherence and partial adherence, the percentage reached was 54%; during pregnancy, there was a gradual decrease (from 46% to 39.7%) of women who reported no adherence; there was no significant association between adherence and the sociodemographic, obstetric and clinics characteristics.
Conclusion: The majority of pregnant women in all trimesters of pregnancy reported total or partial adherence to PFME; it was highly positive the proportion of women who reported performing PFME
Regression Models Analysis for the Degradation of Polystyrene Waste by Thermogravimetric Data
Plastics are known for their beneficial properties, such as lightness, strength, and low cost, and they are used in different applications such as construction, electronics, and packaging. However, plastics do not degrade naturally, accumulating in soils and affecting the environment. Recycling techniques have been developed to minimize plastic waste; chemical recycling through pyrolysis has been cataloged as an effective method for transforming plastic waste into high-value products in the chemical and petrochemical industry. Previous studies of feedstock degradation through thermogravimetry analysis (TGA) have been essential to estimate the optimal temperature ranges to evaluate the pyrolysis process. The present work aims to study regression models to estimate the temperature degradation of polystyrene (PS) through thermogravimetry data, which can be applied before the pyrolysis process. In addition, this work compares linear and polynomial regression models to estimate the best-fitting model and to determine the maximum temperature of degradation of PS by different heating rates. Relative errors were calculated by comparing them with experimental values from the literature not included in the models. As a result, a polynomial model of a fourth-order obtained a better fit with an r2=70.45 % compared to the linear models, where the best fit was obtained with r2= 69.71 %. However, a higher relative error was obtained, with the polynomial models being the lowest, 7.35 and 0.50 % for 15 and 60 °C min-1; for the linear models, 7.05 and 0.39 % were obtained for heating rates of 15 and 60 °C min-1, respectively
Liquid flow-focused by a gas: jetting, dripping and recirculation
The liquid cone-jet mode can be produced upon stimulation by a co-flowing gas
sheath. Most applications deal with the jet breakup, leading to either of two
droplet generation regimes: jetting and dripping. The cone-jet flow pattern is
explored by direct axisymmetric VOF numerical simulation; its evolution is
studied as the liquid flow-rate is increased around the jetting-dripping
transition. As observed in other focused flows such as electrospraying cones
upon steady thread emission, the flow displays a strong recirculating pattern
within the conical meniscus; it is shown to play a role on the stability of the
system, being a precursor to the onset of dripping. Close to the minimum liquid
flow rate for steady jetting, the recirculation cell penetrates into the feed
tube. Both the jet diameter and the size of the cell are accurately estimated
by a simple theoretical model. In addition, the transition from jetting to
dripping is numerically analyzed in detail in some illustrative cases, and
compared, to good agreement, with a set of experiments.Comment: Submitted to the Physical Review E on December 8th, 200
La Informática como materia fundamental en un sistema educativo del siglo XXI
Es innegable la importancia que ha alcanzado la informática en la sociedad, y ya es imprescindible para entender y tener éxito en el mundo actual. Sin embargo, en el currículo educativo de primaria y secundaria esta importancia no se ve reflejada, y la informática aparece como asignatura complementaria orientada a usuarios. Creemos que ha llegado el momento de que, al igual que en otros países avanzados, la informática dé el paso a materia troncal. Con la reciente reforma de la LOMCE se ha perdido una buena oportunidad para esto. Sin embargo, esto puede paliarse mediante la definición de una asignatura con estructura y contenidos concretos orientada al pensamiento computacional y a la formación de creadores.The importance of computing in our society is undeniable. It is essential to understand and be successful in the current world. However, the educational curricula for primary and secondary school does not reflect this, and computing appears just as a useroriented, complementary subject. We believe that the time has come for computing to be a core area, as it is in other advanced countries. The recent reformation of the education law in Spain (LOMCE) was a missed opportunity to achieve this. Nevertheless, it can be somehow remedied by defining a subject with a structure and concrete contents, oriented towards the computational thinking and the developing of creators
Planet-star interactions with precise transit timing. III. Entering the regime of dynamical tides
Hot Jupiters on extremely short-period orbits are expected to be unstable to
tidal dissipation and spiral toward their host stars. That is because they
transfer the angular momentum of the orbital motion through tidal dissipation
into the stellar interior. Although the magnitude of this phenomenon is related
to the physical properties of a specific star-planet system, statistical
studies show that tidal dissipation might shape the architecture of hot Jupiter
systems during the stellar lifetime on the main sequence. The efficiency of
tidal dissipation remains poorly constrained in star-planet systems. Stellar
interior models show that the dissipation of dynamical tides in radiation zones
could be the dominant mechanism driving planetary orbital decay. These
theoretical predictions can be verified with the transit timing method. We
acquired new precise transit mid-times for five planets. They were previously
identified as the best candidates for which orbital decay might be detected.
Analysis of the timing data allowed us to place tighter constraints on the
orbital decay rate. No statistically significant changes in their orbital
periods were detected for all five hot Jupiters in systems HAT-P-23, KELT-1,
KELT-16, WASP-18, and WASP-103. For planets HAT-P-23 b, WASP-18 b, and WASP-103
b, observations show that the mechanism of the dynamical tides dissipation
probably does not operate in their host stars, preventing them from rapid
orbital decay. This finding aligns with the models of stellar interiors of
F-type stars, in which dynamical tides are not fully damped due to convective
cores. For KELT-16 b, the span of transit timing data was not long enough to
verify the theoretical predictions. KELT-1 b was identified as a potential
laboratory for studying the dissipative tidal interactions of inertial waves in
a convective layer.Comment: Accepted for publication in A&
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