1,111 research outputs found
Empirical studies of open source evolution
Copyright @ 2008 Springer-VerlagThis chapter presents a sample of empirical studies of Open Source Software (OSS) evolution. According to these studies, the classical results from the studies of proprietary software evoltion, such as Lehman’s laws of software evolution, might need to be revised, if not fully, at least in part, to account for the OSS observations. The book chapter also summarises what appears to be the empirical
status of each of Lehman’s laws with respect to OSS and highlights the threads to
validity that frequently emerge in these empirical studies. The chapter also discusses
related topics for further research
Mobile Robot Lab Project to Introduce Engineering Students to Fault Diagnosis in Mechatronic Systems
This document is a self-archiving copy of the accepted version of the paper.
Please find the final published version in IEEEXplore: http://dx.doi.org/10.1109/TE.2014.2358551This paper proposes lab work for learning fault detection and diagnosis (FDD) in mechatronic systems. These skills are important for engineering education because FDD is a key capability of competitive processes and products. The intended outcome of the lab work is that students become aware of the importance of faulty conditions and learn to design FDD strategies for a real system. To this end, the paper proposes a lab project where students are requested to develop a discrete event dynamic system (DEDS) diagnosis to cope with two faulty conditions in an autonomous mobile robot task. A sample solution is discussed for LEGO Mindstorms NXT robots with LabVIEW. This innovative practice is relevant to higher education engineering courses related to mechatronics, robotics, or DEDS. Results are also given of the application of this strategy as part of a postgraduate course on fault-tolerant mechatronic systems.This work was supported in part by the Spanish CICYT under Project DPI2011-22443
Was There a Cambrian Explosion on Land? The Case of Arthropod Terrestrialization
Arthropods, the most diverse form of macroscopic life in the history of the Earth, originated in the sea. Since the early Cambrian, at least ~518 million years ago, these animals have dominated the oceans of the world. By the Silurian-Devonian, the fossil record attests to arthropods becoming the first animals to colonize land, However, a growing body of molecular dating and palaeontological evidence suggests that the three major terrestrial arthropod groups (myriapods, hexapods, and arachnids), as well as vascular plants, may have invaded land as early as the Cambrian-Ordovician. These dates precede the oldest fossil evidence of those groups and suggest an unrecorded continental 'Cambrian explosion' a hundred million years prior to the formation of early complex terrestrial ecosystems in the Silurian-Devonian. We review the palaeontological, phylogenomic, and molecular clock evidence pertaining to the proposed Cambrian terrestrialization of the arthropods. We argue that despite the challenges posed by incomplete preservation and the scarcity of early Palaeozoic terrestrial deposits, the discrepancy between molecular clock estimates and the fossil record is narrower than is often claimed. We discuss strategies for closing the gap between molecular clock estimates and fossil data in the evolution of early ecosystems on lan
Effectiveness of a program of romana’s Pilates for non-specific low back pain: A pilot study
Objetivo: comprobar la efectividad del método Pilates Romana para conseguir
una mayor flexibilidad de la columna, junto con una mejora en la movilidad de la
misma, así como del dolor que presentan en su vida diaria los pacientes.
Metodología: ensayo clínico con intención de tratar a treinta pacientes con dolor
lumbar inespecífico. Asistieron a 15 sesiones, 2 veces a la semana, del Método
Pilates Romana.. Se evaluaron parámetros tales como dolor, test de Schöber,
SRS-22 y distancia dedos- suelo.
Resultados. Se encontraron diferencias estadísticamente significativas con
respecto al dolor (escala EVA), distancia dedos- suelo, test de Schöber
(flexibilidad en plano sagital), flexión lateral (flexibilidad en plano frontal) y en
varios ítems de la escala SRS-22, con valores de p<0,001. Por ello, este método
puede ser usado para mejorar el dolor, la flexibilidad axial, la función y los
aspectos relacionados con la calidad de vidaAim: to test the effectiveness of the Romana’s Pilates method to obtain
increased flexibility, improvements in mobility, and reduced pain in daily life.
Methodology: a clinical trial with intention-to-treat thirty patients with nonspecific
low back pain. Participants attended 15 sessions, twice a week. The
Romana’s Pilates method was taught by an external physiotherapist.
Parameters such as pain, the Schober test, and the SRS-22 were evaluated.
Results: Statistically significant differences in pain (VAS), the Schober test
(flexibility in sagittal plane), lateral flexion (flexibility in frontal plane) and several
items of the SRS-22 scale were found, with p <0.001.
This method may be used to improve pain, axial flexibility, function and aspects
related to the quality of life of patient
Evaluation of the ATB 32C, automicrobic system and API 20C using clinical yeast isolates
The ATB 32C (bioMerieux, Spain), AMS-YBC (Vitek System, bioMerieux, Spain) and API 20C (bioMerieux, Spain) systems were evaluated for their reliability in identifying 100 clinical yeast isolates. The ATB 32C, AMS-YBC and API 20C systems correctly identified 97%, 98% and 100% of the isolates respectively. There were no significant differences in incubation periods between ATB 32C and AMS-YBC systems. One isolate of Candida tropicalis was wrongly identified by the ATB 32C and the AMS-YBC systems. The Saccharomyces cerevisiae isolate was wrongly identified by the ATB 32C system while the AMS-YBC failed to identify it and a third isolate of Candida krusei was wrongly identified by the ATB 32C system. The overall accuracy and rapidity of the ATB 32C and AMS-YBC systems were sufficient to permit recommendation of either of these systems for routine use in the clinical microbiology laboratory, although the first system enjoys the advantages of having a wider data-base and the possibility of manual reading
A step ahead on efficient microwave heating for kaolinite
[EN] The thermal evolution of kaolin clay under microwave radiation shows an unexpected large heating rate up to 500 degrees C/min for temperatures > 650 degrees C. Such heating rate is associated with a resistivity drop of > 10(3) Omega.m observed after the dehydroxylation process of the kaolin structure. The high efficiency of the microwave heating effect is correlated with the presence of surface carriers that absorbs microwaves electromagnetic field. The layered structure of the clay-based materials allows the appearance of charge carriers at the surface of the crystal lattice that is electromagnetically activated. This effect represents a breakthrough in the efficient use of microwaves energy in order to produce efficient thermal treatments in large volume of non-metallic minerals with a drastic reduction of the greenhouse gasses for mass production industries.The authors express their thanks to the project MAT-2017-86450-C4-1-R from the Spanis Goverment for the financial support.Reinosa, JJ.; García-Baños, B.; Catalá Civera, JM.; Fernández Lozano, JF. (2019). A step ahead on efficient microwave heating for kaolinite. Applied Clay Science. 168:237-243. https://doi.org/10.1016/j.clay.2018.11.001S23724316
The Lysholm score: Cross cultural validation and evaluation of psychometric properties of the Spanish version
This study aims at assessing the validity and reliability of the Spanish version of the Lysholm
score, a widely used instrument for assessing knee function and activity level after ligament
injuries. Ninety-five participants (67.4% male, 22±5 years) completed the questionnaire twice within
7 days and a subsample of 42 participants completed a test-retest reliability. Reliability,
validity and feasibility psychometric properties were studied. The validity of the questionnaire
was analysed using ceiling and floor effects. Factor structure and construct validity
were analysed with the SF-36, the Hip and Knee Questionnaire (HKQ) and one leg jump
test (OLJT). Criterion validity with the SF-36 Physical State was moderate (r = 0.50 and p<0.01), poor
and inverse relationship (r = -0.31, p<0.01) with HKQ and positive moderate (r = 0.59,
p<0.01) with OLJT. Measurement error from MDC90 was 3.9%. Exploratory factor analysis
demonstrated a one-factor solution explaining 51.5% of total variance. The x2 test for the
one-factor model was significant (x2 = 29.58, df = 20, p < 0.08). Test-retest reliability level
was high (ICC2.1 = 0.92, p<0.01) and also the internal consistency (α = 0.77). The Spanish Lysholm score demonstrated that it is a reliable and valid instrument that can
be used to assess knee function after ligament injuries.This study takes place thanks to the
additional funding from the University of Granada,
Plan Propio de Investigación 2016, Excellence
actions: Units of Excellence; Unit of Excellence on
Exercise and Health (UCEES)
Development and Evaluation of Fuzzy Logic Controllers for Improving Performance of Wind Turbines on Semi-Submersible Platforms under Different Wind Scenarios
Among renewable energy technologies, wind energy features one of the best possibilities for large-scale integration into power systems. However, there are specific restrictions regarding the installation areas for this technology, thus resulting in a growing, yet restricted, rate of penetration of the technology because of the limited viable sites onshore or in shallow waters. In this context, the use of offshore semi-submersible platforms appears as a promising option, which additionally enables the incorporation of other elements, such as wave energy converters or aquaculture. Nevertheless, this kind of offshore facility involves interactions between platform movements and the wind turbine, increasing the complexity of the system, causing traditional control techniques to not be able to fully cope with the dynamics of the system, and thus limiting the efficiency of energy extraction. On the contrary, the use of intelligent control techniques is an interesting option to take full account of the said interactions and to improve energy capture efficiency through the control of the pitch of the blades, especially under turbulent, above-rated wind profiles. This work presents an original fuzzy logic controller that has been validated by comparing it with previously validated controllers, following a developed methodology that allows comparison of controllers for wind turbines in semi-submersible platforms using performance indexes.This work was partially supported by the Ministry of Economy and Competitiveness (Government of Spain) and European Union (RTC-2016-5712-3); by the European Union, CDTI (Spain) and BEISS (UK) through the call H2020 ERA-NET DEMOWIND (WIP10+ project); by the Regional Government of Andalusia and European Union (UMA-CEIATECH-18); and finally, by partial funding for open access charge from the Universidad de Málaga. Partial funding for open access charge: Universidad de Málag
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