On the Enforcement of a Class of Nonlinear Constraints on Petri Nets

International audienceThis paper focuses on the enforcement of nonlinear constraints in Petri nets. First, a supervisory structure is proposed for a nonlinear constraint. The proposed structure consists of added places and transitions. It controls the transitions in the net to be controlled only but does not change its states since there is no arc between the added transitions and the places in the original net. Second, an integer linear programming model is proposed to transform a nonlinear constraint to a minimal number of conjunc-tive linear constraints that have the same control performance as the nonlinear one. By using a place invariant based method, the obtained linear constraints can be easily enforced by a set of control places. The control places consist to a supervisor that can enforce the given nonlinear constraint. On condition that the admissible markings space of a nonlinear constraint is non-convex, another integer linear programming model is developed to obtain a minimal number of constraints whose disjunctions are equivalent to the nonlinear constraint. Finally, a number of examples are provided to demonstrate the proposed approach

Using keystroke logging to understand writers’ processes on a reading-into-writing test

Background Integrated reading-into-writing tasks are increasingly used in large-scale language proficiency tests. Such tasks are said to possess higher authenticity as they reflect real-life writing conditions better than independent, writing-only tasks. However, to effectively define the reading-into-writing construct, more empirical evidence regarding how writers compose from sources both in real-life and under test conditions is urgently needed. Most previous process studies used think aloud or questionnaire to collect evidence. These methods rely on participants’ perceptions of their processes, as well as their ability to report them. Findings This paper reports on a small-scale experimental study to explore writers’ processes on a reading-into-writing test by employing keystroke logging. Two L2 postgraduates completed an argumentative essay on computer. Their text production processes were captured by a keystroke logging programme. Students were also interviewed to provide additional information. Keystroke logging like most computing tools provides a range of measures. The study examined the students’ reading-into-writing processes by analysing a selection of the keystroke logging measures in conjunction with students’ final texts and interview protocols. Conclusions The results suggest that the nature of the writers’ reading-into-writing processes might have a major influence on the writer’s final performance. Recommendations for future process studies are provided

BPR best practices for the healthcare domain

Healthcare providers are under pressure to work more efficiently and in a more patient-focused way. One possible way to achieve this is to launch Business Process Redesign (BPR) initiatives, which focus on changing the structure of the involved processes and using IT as an enabler for such changes. In this paper, we argue that a list of historically successful improvement tactics, the BPR best practices, are a highly suitable ingredient for such efforts in the healthcare domain. Our assessment is based on the analysis of 14 case studies. The insights obtained by the analysis also led to an extension of the original set of best practices

Fancine 2003, n. 08

Abstract not availabl

SPECULOOS: a network of robotic telescopes to hunt for terrestrial planets around the nearest ultracool dwarfs

We present here SPECULOOS, a new exoplanet transit search based on a network of 1m-class robotic telescopes targeting the $\sim$1200 ultracool (spectral type M7 and later) dwarfs bright enough in the infrared ($K$-mag $\leq 12.5$) to possibly enable the atmospheric characterization of temperate terrestrial planets with next-generation facilities like the $\textit{James Webb Space Telescope}$. The ultimate goals of the project are to reveal the frequency of temperate terrestrial planets around the lowest-mass stars and brown dwarfs, to probe the diversity of their bulk compositions, atmospheres and surface conditions, and to assess their potential habitability.Comment: 21 pages, 13 figures, 1 table. Proceedings of SPI

TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf

Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of these systems. Aims. In this study we present the discovery of TOI-2257 b (TIC 198485881), a long-period (35 d) sub-Neptune orbiting an M3 star at 57.8 pc. Its transit depth is about 0.4%, large enough to be detected with medium-size, ground-based telescopes. The long transit duration suggests the planet is in a highly eccentric orbit (e ∼ 0.5), which would make it the most eccentric planet known to be transiting an M-dwarf star. Methods. We combined TESS and ground-based data obtained with the 1.0-meter SAINT-EX, 0.60-meter TRAPPIST-North, and 1.2-meter FLWO telescopes to find a planetary size of 2.2 R⊕ and an orbital period of 35.19 days. In addition, we make use of archival data, high-resolution imaging, and vetting packages to support our planetary interpretation. Results. With its long period and high eccentricity, TOI-2257 b falls into a novel slice of parameter space. Despite the planet’s low equilibrium temperature (∼256 K), its host star’s small size (R∗ = 0.311 ± 0.015) and relative infrared brightness (Kmag = 10.7) make it a suitable candidate for atmospheric exploration via transmission spectroscopy.Fil: Schanche, N.. University of Bern; SuizaFil: Pozuelos, F. J.. Université de Liège; BélgicaFil: Günther, M. N.. Massachusetts Institute of Technology; Estados Unidos. Agencia Espacial Europea. European Space Research And Technology Centre.; Países BajosFil: Wells, R. D.. University of Bern; SuizaFil: Burgasser, A. J.. University of California at San Diego; Estados UnidosFil: Chinchilla, P.. Université de Liège; Bélgica. Instituto de Astrofísica de Canarias; EspañaFil: Delrez, L.. Université de Liège; BélgicaFil: Ducrot, E.. Université de Liège; BélgicaFil: Garcia, L. J.. Université de Liège; BélgicaFil: Gómez Maqueo Chew, Y.. Universidad Nacional Autónoma de México. Instituto de Astronomía; MéxicoFil: Jofre, Jorge Emiliano. Universidad Nacional Autónoma de México. Instituto de Astronomía; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Rackham, B. V.. Massachusetts Institute of Technology; Estados UnidosFil: Sebastian, D.. University of Birmingham; Reino UnidoFil: Stassun, K. G.. Vanderbilt University; Estados UnidosFil: Stern, D.. California Instituto Of Technology. Departament Of Mechanical And Civil Engineering; Estados UnidosFil: Timmermans, M.. Université de Liège; BélgicaFil: Barkaoui, K.. Université de Liège; Bélgica. Cadi Ayyad University; MarruecosFil: Belinski, A.. Moscow State University; RusiaFil: Benkhaldoun, Z.. Cadi Ayyad University; MarruecosFil: Benz, W.. University of Bern; SuizaFil: Bieryla, A.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Bouchy, F.. Observatorio de Ginebra; SuizaFil: Burdanov, A.. Massachusetts Institute of Technology; Estados UnidosFil: Charbonneau, D.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Christiansen, J. L.. Centro de Análisis y Procesamiento Infrarrojo; Estados Unidos. National Aeronautics and Space Administration; Estados UnidosFil: Collins, K. A.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Demory, Brice Olivier. University of Bern; SuizaFil: Dévora Pajares, M.. Universidad de Granada; EspañaFil: De Wit, J.. Massachusetts Institute of Technology; Estados UnidosFil: Dragomir, D.. University of New Mexico; Estados Unido

TOI-3235 b: A Transiting Giant Planet around an M4 Dwarf Star

We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry and confirmed with radial velocities from ESPRESSO and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of 0.665 ± 0.025 M J and a radius of 1.017 ± 0.044 R J. It orbits close to its host star, with an orbital period of 2.5926 days but has an equilibrium temperature of ≈ 604 K, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of 0.3939 ± 0.0030 M ☉, a radius of 0.3697 ± 0.0018 R ☉, an effective temperature of 3389 K, and a J-band magnitude of 11.706 ± 0.025. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M dwarfs for atmospheric characterization

Vetting Of 384 TESS Objects Of Interest With TRICERATOPS And Statistical Validation Of 12 Planet Candidates

We present TRICERATOPS, a new Bayesian tool that can be used to vet and validate TESS Objects of Interest (TOIs). We test the tool on 68 TOIs that have been previously confirmed as planets or rejected as astrophysical false positives. By looking in the false-positive probability (FPP)−nearby false-positive probability (NFPP) plane, we define criteria that TOIs must meet to be classified as validated planets (FPP \u3c 0.015 and NFPP \u3c 10−3), likely planets (FPP \u3c 0.5 and NFPP \u3c 10−3), and likely nearby false positives (NFPP \u3e 10−1). We apply this procedure on 384 unclassified TOIs and statistically validate 12, classify 125 as likely planets, and classify 52 as likely nearby false positives. Of the 12 statistically validated planets, 9 are newly validated. TRICERATOPS is currently the only TESS vetting and validation tool that models transits from nearby contaminant stars in addition to the target star. We therefore encourage use of this tool to prioritize follow-up observations that confirm bona fide planets and identify false positives originating from nearby stars