712 research outputs found

    Synthesizing SystemC Code from Delay Hybrid CSP

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    Delay is omnipresent in modern control systems, which can prompt oscillations and may cause deterioration of control performance, invalidate both stability and safety properties. This implies that safety or stability certificates obtained on idealized, delay-free models of systems prone to delayed coupling may be erratic, and further the incorrectness of the executable code generated from these models. However, automated methods for system verification and code generation that ought to address models of system dynamics reflecting delays have not been paid enough attention yet in the computer science community. In our previous work, on one hand, we investigated the verification of delay dynamical and hybrid systems; on the other hand, we also addressed how to synthesize SystemC code from a verified hybrid system modelled by Hybrid CSP (HCSP) without delay. In this paper, we give a first attempt to synthesize SystemC code from a verified delay hybrid system modelled by Delay HCSP (dHCSP), which is an extension of HCSP by replacing ordinary differential equations (ODEs) with delay differential equations (DDEs). We implement a tool to support the automatic translation from dHCSP to SystemC

    Performance Assessment and Mathematical Modeling of Process Parameters in Electrical Discharge Machining of EN-31 Tool Steel Material Using Taguchi DOE

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    In non-traditional machining, electrical discharge machining (EDM) has tremendous potential on account of versatility of its applications and is successfully, commercially used in modern industries. EDM process is capable to machine geometrically complex, hard material components, tool steels, composites, super alloys, ceramics and carbides. In EDM, Material Removal Rate (MRR) and Tool wear rate (TWR) are generally analyzed to assess its performance. For this, a perfect combination of input variables is required. In the present study, machining is done on Tool steel workpiece material using a pure copper electrode. The input parameters like Pulse-ON time, Pulse- OFF time, Current and Gap voltage are selected for experimentation and Taguchi method is employed for the DOE by considering 4 factors and 3 levels. A total of 27 experiments (L27 orthogonal array) have been designed with a possible combination of selected input parameters. The present work mainly focuses on development of an extensive mathematical model for correlating the input and output variables using a conventional regression analysis. The adequacy of proposed model was tested with the help of some collected data through experimentation using taguchi optimized DOE. The proposed linear multi-variable regression equation was found to be a best fitted model with 98% confidence levels.In non-traditional machining, electrical discharge machining (EDM) has tremendous potential on account of versatility of its applications and is successfully, commercially used in modern industries. EDM process is capable to machine geometrically complex, hard material components, tool steels, composites, super alloys, ceramics and carbides. In EDM, Material Removal Rate (MRR) and Tool wear rate (TWR) are generally analyzed to assess its performance. For this, a perfect combination of input variables is required. In the present study, machining is done on Tool steel workpiece material using a pure copper electrode. The input parameters like Pulse-ON time, Pulse- OFF time, Current and Gap voltage are selected for experimentation and Taguchi method is employed for the DOE by considering 4 factors and 3 levels. A total of 27 experiments (L27 orthogonal array) have been designed with a possible combination of selected input parameters. The present work mainly focuses on development of an extensive mathematical model for correlating the input and output variables using a conventional regression analysis. The adequacy of proposed model was tested with the help of some collected data through experimentation using taguchi optimized DOE. The proposed linear multi-variable regression equation was found to be a best fitted model with 98% confidence levels

    Macrofaunal communities in the Gioia Canyon (Southern Tyrrhenian Sea, Italy)

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    Submarine canyons play pivotal roles in the physical, biological and ecological processes of coastal areas, especially in closed or semi-closed basins as the Mediterranean Sea, influencing the biodiversity and the abundance of the benthic fauna. On February 2013, during the Tyrrhenian Gravity Flows (TyGraF) campaign, samples have been collected along the Gioia Canyon Basin (Italy) with the aim to describe the taxonomical composition and the abundances of the macrobenthic assemblages, filling the gap of knowledge in this area. A total of 93 taxa were identified, and the Annelida was the phylum with the highest number of specimens and most diversified (46 taxa). The polychaetes Sternaspis scutata, Prionospio cirrifera and Monticellina sp., the bivalves Thyasira sp.1 and Saccella commutata and the amphipods belonging to the genera Ampelisca and Harpinia showed the highest densities in the studied area; however, results suggest low values of the abundances of the macrobenthos if compared with those generally reported for other canyons, both inside and outside the Mediterranean Sea. The marine biotic index (AMBI) highlights that the canyon system and the surrounded area were slightly disturbed and characterized by a high percentage of tolerant taxa. This study is the first baseline for future analyses of the macrobenthic communities of this area

    In Absentia: an Exploratory Study of How Patients are Considered in Multidisciplinary Cancer Team Meetings

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    Background: Multidisciplinary team meetings and shared decision-making are potential means of delivering patient-centred care. Not much is known about how those two paradigms fit together in cancer care. This study aimed to investigate how decisions are made in multidisciplinary team meetings and whether patient perspectives are incorporated in these decisions. Materials and Methods: A qualitative study was conducted using non-participant observation at multidisciplinary team meetings (also called tumor boards) at the University Cancer Center Hamburg-Eppendorf, Germany. Two researchers recorded structured field notes from a total of N = 15 multidisciplinary team meetings. Data were analyzed using content analysis and descriptive statistics. Results: Physicians mainly exchanged medical information and based their decision-making on this information. Individual patient characteristics or their treatment preferences were rarely considered or discussed. In the few cases where patient preferences were raised as a topic, this information did not seem to be taken into account in decision-making processes about treatment recommendations. Conclusion: The processes in multidisciplinary team meetings we observed did not exhibit shared decision-making. Patient perspectives were absent. If multidisciplinary team meetings wish to become more patient-centred they will have to modify their processes and find a way to include patient preferences into the decision-making process

    Lazy Abstraction-Based Controller Synthesis

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    We present lazy abstraction-based controller synthesis (ABCS) for continuous-time nonlinear dynamical systems against reach-avoid and safety specifications. State-of-the-art multi-layered ABCS pre-computes multiple finite-state abstractions of varying granularity and applies reactive synthesis to the coarsest abstraction whenever feasible, but adaptively considers finer abstractions when necessary. Lazy ABCS improves this technique by constructing abstractions on demand. Our insight is that the abstract transition relation only needs to be locally computed for a small set of frontier states at the precision currently required by the synthesis algorithm. We show that lazy ABCS can significantly outperform previous multi-layered ABCS algorithms: on standard benchmarks, lazy ABCS is more than 4 times faster

    Particle-Filtering-Based State-of-Health Estimation and End-of-Life Prognosis for Lithium-Ion Batteries at Operation Temperature

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    We present the implementation of a particle-filtering-based framework that estimates the State-of-Health (SOH) and predicts the End-of-Life (EOL) of Lithium-Ion batteries, efficiently incorporating variations of ambient temperature in the analysis. The proposed approach uses an empirical state-space model, in which inputs are explicitly defined as the average temperature of operation and the output of an external module that detects self-recharge phenomena, on the other hand the output is a function that relates the current SOH and temperature with the Usable Capacity in that cycle. In addition, this approach allows to deal with data losses and outliers. In order to correct erroneous initial conditions in state estimates, an Outer Feedback Correction Loop is implemented. Finally, this framework is validated using degradation data from four sources: experimental degradation data from two Li-Ion 18650 cells, accelerated degradation data openly provided by NASA Ames Research Center, and artificially generated degradation data at different ambient temperatures.We present the implementation of a particle-filtering-based framework that estimates the State-of-Health (SOH) and predicts the End-of-Life (EOL) of Lithium-Ion batteries, efficiently incorporating variations of ambient temperature in the analysis. The proposed approach uses an empirical state-space model, in which inputs are explicitly defined as the average temperature of operation and the output of an external module that detects self-recharge phenomena, on the other hand the output is a function that relates the current SOH and temperature with the Usable Capacity in that cycle. In addition, this approach allows to deal with data losses and outliers. In order to correct erroneous initial conditions in state estimates, an Outer Feedback Correction Loop is implemented. Finally, this framework is validated using degradation data from four sources: experimental degradation data from two Li-Ion 18650 cells, accelerated degradation data openly provided by NASA Ames Research Center, and artificially generated degradation data at different ambient temperatures

    A novel combination of CYP51A mutations confers pan-azole resistance in aspergillus fumigatus

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    The treatment of invasive and chronic aspergillosis involves triazole drugs. Its intensive use has resulted in the selection of resistant isolates, and at present, azole resistance in Aspergillus fumigatus is considered an emerging threat to public health worldwide. The aim of this work is to uncover the molecular mechanism implicated in the azole resistance phenotype of three Aspergillus fumigatus clinical strains isolated from an Argentinian cystic fibrosis patient under long-term triazole treatment. Strain susceptibilities were assessed, and CYP51A gene sequences were analyzed. Two of the studied Aspergillus fumigatus strains harbored the TR34- L98H allele. These strains showed high MIC values for all tested triazoles (>16.00μg/ml, 1.00 μg/ml, 1.00 μg/ml, and 2.00 μg/ml for itraconazole, isavuconazole, posaconazole, and voriconazole, respectively). The third strain had a novel amino acid change (R65K) combined with the TR34-L98H mutations. This new mutation combination induces a pan-azole MIC augment compared with TR34-L98H mutants (>16 μg/ml, 4.00μg/ml, 4.00μg/ml, and 8.00μg/ml for itraconazole, isavuconazole, posaconazole, and voriconazole, respectively). The strain harboring the TR34-R65K-L98H allele showed no inhibition halo when voriconazole susceptibility was evaluated by disk diffusion. The effect of these mutations in the azole-resistant phenotype was confirmed by gene replacement experiments. Transformants harboring the TR34-L98H and TR34-R65KL98H alleles mimicked the azole-resistant phenotype of the clinical isolates, while the incorporation of the TR34-R65K and R65K alleles did not significantly increase azole MIC values. This is the first report of the TR34-L98H allele in Argentina. Moreover, a novel CYP51A allele (TR34-R65K-L98H) that induces a pan-azole MIC augment is described.Fil: Macedo, Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Brito Devoto, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Pola, Santiago. Universidad de Buenos Aires; ArgentinaFil: Finquelievich, Jorge L.. Universidad de Buenos Aires; ArgentinaFil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Garcia Effron, Guillermo. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

    Coercive and anisotropy fields in patterned amorphous FeSi submicrometric structures

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    Amorphous FexSi12x films have been prepared on Si substrates in order to fabricate submicrometric magnetic structures with soft magnetic behavior. The magnetic properties compositional dependence of the unpatterned samples has been analyzed to select the Fe content (x50.7) with the lowest coercive and anisotropy fields values. Arrays of Fe0.7Si0.3 lines have been fabricated by electron beam lithography combined with a liftoff technique, with typical dimensions of 200 nm linewidth and 1 mm line spacing. These arrays present coercive fields parallel to the line direction as small as 9 Oe.Peer reviewe

    Recent freshening and cooling of Biscay subsurface waters

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    The monitoring program Radiales (https://www.seriestemporales-ieo.net/) by the Spanish Institute of Oceanography, has been providing hydrographical and biogeochemical series in marine waters around Spain on a monthly basis from early 90's. The proximity of the shelf-break in front of the city of Santander (SE Bay of Biscay) allowed tracking intermediate and deep waters along the standard section perpendicular to this city for three decades (sampling was limited to 1000 meter until late 2007, then extended to 1500 m, and full-depth 2400 m since 2014). From the start of the sampling in nearly 90`s, subsurface waters showed unabated warming and salt-increase. Warming was linked to isopycnal sinking (heave) during the 90`s and early 00`s until the occurrence of very strong winter mixing in 2005 that shifted quickly the salinity down to lower East North Atlantic Central Waters (ENACW) levels (ca. 400 m). Overall, warming and salt-increase at the core of ENACW added up to 0.3ºC and 0.08 in salinity within only two and a bit decades. In 2014, the upper central waters showed freshening and cooling for the first time in the series, a process that enhanced in the following years especially in salinity that currently (2021) presents the lowest value of the overall timeseries. This shift in regional hydrography follows the large salinity drop observed in the subpolar gyre around 2012 and its subsequent expansion downstream into the subtropical gyre and subarctic seas. This regime shift implies that subsurface environmental conditions in the region have returned back to 90`s state, contrasting to the uppermost waters which continue to show large positive anomalies. The effects of this cold and freshwater inflow in the regional circulation of southern Biscay are discussed
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