321 research outputs found
How do Developers Improve Code Readability? An Empirical Study of Pull Requests
Readability models and tools have been proposed to measure the effort to read
code. However, these models are not completely able to capture the quality
improvements in code as perceived by developers. To investigate possible
features for new readability models and production-ready tools, we aim to
better understand the types of readability improvements performed by developers
when actually improving code readability, and identify discrepancies between
suggestions of automatic static tools and the actual improvements performed by
developers. We collected 370 code readability improvements from 284 Merged Pull
Requests (PRs) under 109 GitHub repositories and produce a catalog with 26
different types of code readability improvements, where in most of the
scenarios, the developers improved the code readability to be more intuitive,
modular, and less verbose. Surprisingly, SonarQube only detected 26 out of the
370 code readability improvements. This suggests that some of the catalog
produced has not yet been addressed by SonarQube rules, highlighting the
potential for improvement in Automatic static analysis tools (ASAT) code
readability rules as they are perceived by developers
Autonomous Navigation System for a Delivery Drone
The use of delivery services is an increasing trend worldwide, further
enhanced by the COVID pandemic. In this context, drone delivery systems are of
great interest as they may allow for faster and cheaper deliveries. This paper
presents a navigation system that makes feasible the delivery of parcels with
autonomous drones. The system generates a path between a start and a final
point and controls the drone to follow this path based on its localization
obtained through GPS, 9DoF IMU, and barometer. In the landing phase,
information of poses estimated by a marker (ArUco) detection technique using a
camera, ultra-wideband (UWB) devices, and the drone's software estimation are
merged by utilizing an Extended Kalman Filter algorithm to improve the landing
precision. A vector field-based method controls the drone to follow the desired
path smoothly, reducing vibrations or harsh movements that could harm the
transported parcel. Real experiments validate the delivery strategy and allow
to evaluate the performance of the adopted techniques. Preliminary results
state the viability of our proposal for autonomous drone delivery.Comment: 12 pages, 15 figures, extended version of an paper published at the
XXIII Brazilian Congress of Automatica, entitled "Desenvolvimento de um drone
aut\^onomo para tarefas de entrega de carga
A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
Stellar evolution tracks and isochrones are key inputs for a wide range of
astrophysical studies; in particular, they are essential to the interpretation
of photometric and spectroscopic observations of resolved and unresolved
stellar populations. We have made available to the astrophysical community a
large, homogenous database of up-to-date stellar tracks and isochrones, and a
set of programs useful in population synthesis studies.
In this paper we first summarize the main properties of our stellar model
database (BaSTI) already introduced in Pietrinferni et al. (2004) and
Pietrinferni et al. (2006). We then discuss an important update of the
database, i.e., the extension of all stellar models and isochrones until the
end of the thermal pulses along the Asymptotic Giant Branch. This extension of
the library is particularly relevant for stellar population analyses in the
near-infrared, or longer wavelengths, where the contribution to the integrated
photometric properties by cool and bright Asymptotic Giant Branch stars is
significant. A few comparisons with empirical data are also presentend and
briefly discussed. We then present three web-tools that allow an interactive
access to the database, and make possible to compute user-specified
evolutionary tracks, isochrones, stellar luminosity functions, plus synthetic
Color-Magnitude-Diagrams and integrated magnitudes for arbitrary Star Formation
Histories. All these web tools are available at the BaSTI database official
site: http://www.oa-teramo.inaf.it/BASTI.Comment: 18 pages, 5 tables, 7 figures, accepted in The Astronomical Journal.
The BaSTI database and its web-tools are available on the web
http://www.oa-teramo.inaf.it/BASTI. The web-tools are also mirrored in the
BaSTI section of http://astro.ensc-rennes.f
Process modeling and control applied to real-time monitoring of distillation processes by near-infrared spectroscopy
A distillation device that acquires continuous and synchronized measurements of temperature, percentage of distilled fraction and NIR spectra has been designed for real-time monitoring of distillation processes. As a process model, synthetic commercial gasoline batches produced in Brazil, which contain mixtures of pure gasoline blended with ethanol have been analyzed. The information provided by this device, i.e., distillation curves and NIR spectra, has served as initial information for the proposal of new strategies of process modeling and multivariate statistical process control (MSPC). Process modeling based on PCA batch analysis provided global distillation trajectories, whereas multiset MCR-ALS analysis is proposed to obtain a component-wise characterization of the distillation evolution and distilled fractions. Distillation curves, NIR spectra or compressed NIR information under the form of PCA scores and MCR-ALS concentration profiles were tested as the seed information to build MSPC models. New on-line PCA-based MSPC approaches, some inspired on local rank exploratory methods for process analysis, are proposed and work as follows: a)MSPC based on individual process observation models, where multiple local PCA models are built considering the sole information in each observation point; b) Fixed Size Moving Window - MSPC, in which local PCA models are built considering a moving window of the current and few past observation points; and c) Evolving MSPC, where local PCA models are built with an increasing window of observations covering all points since the beginning of the process until the current observation. Performance of different approaches has been assessed in terms of sensitivity to fault detection and number of false alarms. The outcome of this work will be of general use to define strategies for on-line process monitoring and control and, in a more specific way, to improve quality control of petroleum-derived fuels and other substances submitted to automatic distillation processes monitored by NIRS
A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
We present a large and updated stellar evolution database for low-,
intermediate- and high-mass stars in a wide metallicity range, suitable for
studying Galactic and extragalactic simple and composite stellar populations
using population synthesis techniques. The stellar mass range is between
\sim0.5Mo and 10Mo with a fine mass spacing. The metallicity [Fe/H] comprises
10 values ranging from -2.27 to 0.40, with a scaled solar metal distribution.
The initial He mass fraction ranges from Y=0.245, for the more metal-poor
composition, up to 0.303 for the more metal-rich one, with Delta Y/Delta Z\sim
1.4. For each adopted chemical composition, the evolutionary models have been
computed without and with overshooting from the Schwarzschild boundary of the
convective cores during the central H-burning phase. The whole set of
evolutionary models can be used to compute isochrones in a wide age range, from
\sim30 Myr to \sim15Gyr. Both evolutionary tracks and isochrones are available
in several observational planes, employing updated set of bolometric
corrections and color-Te relations computed for this project. The number of
points along the models and the resulting isochrones is selected in such a way
that interpolation for intermediate metallicities not contained in the grid is
straightforward. We compare our isochrones with results from different stellar
evolution databases and perform some empirical tests for the reliability of our
models. Since this work is devoted to scaled solar compositions, we focus our
attention on the Galactic disk populations, employing multicolor photometry of
unevolved field MS stars with precise Hipparcos parallaxes, well-studied open
clusters and one eclipsing binary system with precise measurements of masses,
radii and [Fe/H] of both components.Comment: 57 pages, 26 figures (figs. 3, 4, 6 are at low resolution), ApJ in
press, the whole set of evolutionary results can be retrieved at
http://www.te.astro.it/BASTI/index.ph
Effects of carbonated water injection on the pore system of a carbonate rock (coquina)
CO2 injection is a well-known Enhanced Oil Recovery (EOR) technique that has been used for years to improve oil extraction from carbonate rock and other oil reservoirs. Optimal functioning of CO2 injection requires a thorough understanding of how this method affects the petrophysical properties of the rocks. We evaluated pore-scale changes in these properties, notably porosity and absolute permeability, following injection of CO2-saturated water in two coquina outcrop samples from the Morro do Chaves Formation in Brazil. The coquinas are close analogues of Pre-salt oil reservoirs off the coast of southern Brazil. The effects of carbonated water injection were evaluated using a series of experimental and numerical steps before and after coreflooding: cleaning, basic petrophysics, microtomography (microCT) imaging, nuclear magnetic resonance (NMR) analyses, and pore network modeling (PNM). Our study was motivated by an earlier experiment which did not show the development of a wormhole in the center of the sample, with a concomitant increase in permeability of the coquina as often noted in the literature. We instead observed a substantial decrease in the absolute permeability (between 71 and 77%), but with little effect on the porosity and no wormhole formation. While all tests were carried out on both samples, here we present a comprehensive analysis for one of the samples to illustrate changes at the pore network level. Different techniques were used for the pore-scale analyses, including pore network modeling using PoreStudio, and software developed by the authors to enable a statistical analysis of the pore network. Results provided much insight in how injected carbonated water affects the pore network of carbonate rocks
Central odontogenic fibroma: a case report with long-term follow-up
An osteolytic tumour of the mandible with prominent expansive growth on the alveolar ridge and displacement of the involved teeth is described in a 28-year-old man. The lesion was diagnosed as a central odontogenic fibroma, an uncommon benign neoplasm derived from dental apparatus, and was removed by curettage. The patient remains asymptomatic after thirteen years of follow-up, which supports the claimed indolent behavior of this poorly documented disease and the adequacy of a conservative surgical treatment
Identification of phlebotomine sand fly (Diptera: Psychodidae) in Atlantic forest fragments and their dispersal to urban area
Abstract The geographical distribution of sand flies in Brazil has been the subject of some studies, yet there is no information about the phlebotomine fauna in João Pessoa, State of Paraíba, Brazil. The aim of this work is to evaluate the occurrence and distribution of sand flies in the Atlantic forest fragments and to evaluate a possible dispersion in 06 nearby districts. Light traps were used during three consecutive nights, supplemented by an aspirator during the dry period and rainy season. A total of 222 sand flies were found, 143 (130 males and 13 females) in the Atlantic forest, and 79 in urban areas. During the entire dry season, three species of phlebotomine sand flies were recorded in 11 forest fragments, Lutzomyia longipalpis, Lu. migonei and Lu. whitmani. During the rainy season, only Lu. longipalpis was found. This was the only species identified in the studied neighborhoods during both seasons. The differences in diversity of sand flies encountered between natural habitats and urban areas may thus be correlated mostly with adaptations to particular habitats and availability of food. One species (Lu. longipalpis) appears to be rapidly adapting to urban areas because of deforestation
- …