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

Seamless IPv6 connectivity for two-wheelers

Communications will be a must for two-wheel vehicles integrated into future smart mobility environments. Two-wheelers will be connected with vehicular networks and smart cities, and for this to happen it is necessary not only a base technological support, but also a proper communication middleware able to maintain reachable the bike or moped through the network. In this work, we present a communication node for two-wheelers supporting network mobility and including 3G and 802.11p communication technologies. The communication unit has been designed and prototyped, and it has been provided with an IPv6 communication stack with an enhanced mobility management. The operation of the unit has been assessed in real environments, presenting good performance results and thus offering a novel platform suitable for the next generation of telematics services embracing two-wheelers.This work has been sponsored by the Spanish Ministry of Economy and Competitiveness through the EDISON project (contract TIN2014-52099-R), and the Spanish Ministry of Home Affairs - Department of Transport (DGT) through 545 the S-CICLO project (SPIP2015-01757)

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

Securing vehicular IPv6 communications

A common practice is applying security after a network has been designed or developed. We have the opportunity of not committing this error in vehicular networks. Apart from particular works in the literature, ETSI TC ITS has defined general security services for (vehicular) cooperative systems. However, existent efforts do not pay the needed attention to the integration of IPv6 yet. The potential of IPv6 in the field is being described within ISO TC 204, above all, but further work is needed for a proper integration of security. This work follows this direction, and a reference vehicular communication architecture considering ETSI/ISO regulations, uses Internet Protocol security (IPsec) and Internet Key Exchange version 2 (IKEv2) to secure IPv6 Network Mobility (NEMO). A key advance is also the implementation and experimental evaluation of the proposal in a challenging vertical handover scenario between 3G and 802.11p. The performance of the secured NEMO channel is widely analyzed in terms of the movement speed, bandwidth, traffic type or signal quality, and it is concluded that the addition of IPv6 security only implies a slight reduction in the overall performance, with the great advantage of providing confidentiality, integrity and authenticity to the communication path.This work has been sponsored by the EU 7th Framework Program through the ITSSv6, FOTsis, GEN6 and Inter-Trust projects (contracts 270519, 270447, 297239 and 317731), and the Ministry of Science and Innovation through the Walkie-Talkie project (TIN2011-27543-C03)