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Past global changes are typically registered in both natural (e.g., geologic-geomorphological, atmospheric-climatic, hydrologic-glacial and biological) and cultural records (e.g., archaeological, historical and documentary sources). Nevertheless, there are few sites in the world where sedimentary and archaeological evidence combine to provide information about two or more past millennial climate changes. In this regard, the Roman city of Guadix (Granada, SE Spain) represents a singular location, whose Roman theatre (1st century CE), recently discovered in 2007, contains palaeo-flood evidences that can be related to the two latest global warm periods: the Roman and Medieval epochs. In this research, detailed geological analyses are carried out. These analyses consisted in careful descriptions of vertical stratigraphic sections (lithology, structures…) and lateral correlation panels; as well as fluvial facies models to interpret the sedimentary environments for each sequence. This sedimentological information was combined with the study of archaeological remains, radiocarbon dating and optically stimulated luminescence, and three major flood events have been identified: two of them dating back to the beginning of the 1st century CE (period of the Pax Romana Empire); and the other occurring at the end of the 12th century (Islamic Almohad period). Such extreme hydrological events were synchronous with two warm periods: the Roman Climatic Optimum and the Medieval Warm Period. This seems to suggest that the meteorological fluctuations associated to climate changes during warming periods (such as the current one associated with present-day climate change) very likely produce such extraordinary or extreme events, which can mobilise large amounts of solid load (sands, silts and clays) and trigger sudden changes in the configuration of the river system (channel avulsions, meander cut-offs and captures among tributaries) and alluvial fans (at tributary mouths). We believe that, Interreg SUDOE programme, Dirección General del Agua, IGME-CSIC, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

En el presente estudio se realiza una investigación sobre la mejora de las propiedades geotécnicas y la estabilización de un suelo expansivo mezclándolo con diferentes aditivos, cal, cemento y cenizas volcánicas, en diferentes proporciones. El suelo utilizado son arcillas y limos yesíferos procedentes de Murcia. El objetivo de este estudio es determinar la viabilidad de estabilizar este tipo de materiales con cada uno de los aditivos aplicados (cemento, cenizas volcánicas y cal) para poder darles un uso en obra, evitando así la necesidad de llevarlos a vertederos y pedir préstamos cuando afecten a la proyección de la misma, el cual es un método económicamente más caro. La evaluación de la mejora de las propiedades geotécnicas y la estabilización del material se determina mediante la comparación de los resultados obtenidos en los ensayos de laboratorio realizados, los cuales caracterizan el material, evalúan las propiedades volumétricas y la resistencia, tanto de la muestra en su estado natural, como de las distintas mezclas analizadas con los aditivos indicados. En resumen, los ensayos realizados son, ensayos de identificación y compactación (granulometría escala PHI y láser, límites de Atterberg, ensayo Proctor y peso específico de las partículas sólidas), propiedades químicas y mineralógicas (Fluorescencia de rayos X – FRX, difracción de rayos X – DRX, agregados orientados – AO, determinación de pH y determinación de la conductividad), parámetros resistentes (corte directo) y parámetros de deformabilidad y volumétricos (edómetro, hinchamiento libre).

Elevators are among the oldest and most widespread transportation systems, yet their complexity increases rapidly to satisfy customization demands and to meet quality of service requirements. Verification and validation tasks in this context are costly, since they rely on the manual intervention of domain experts at some points of the process. This is mainly due to the difficulty to assess whether the elevators behave as expected in the different test scenarios, the so-called test oracle problem. Metamorphic testing is a thriving testing technique that alleviates the oracle problem by reasoning on the relations among multiple executions of the system under test, the so-called metamorphic relations. In this practical experience paper, we report on the application of metamorphic testing to verify an industrial elevator dispatcher. Together with domain experts from the elevation sector, we defined multiple metamorphic relations that consider domain-specific quality of service measures. Evaluation results with seeded faults show that the approach is effective at detecting faults automatically.

The time it takes software systems to be tested is usually long. This is often caused by the time it takes the entire test suite to be executed. To optimize this, regression test selection approaches have allowed for improvements to the cost-effectiveness of verification and validation activities in the software industry. In this area, multi-objective algorithms have played a key role in selecting the appropriate subset of test cases from the entire test suite. In this paper, we propose a set of seeding strategies for the test case selection problem that generate the initial population of multi-objective algorithms.We integrated these seeding strategies with an NSGA-II algorithm for solving the test case selection problem in the context of simulation-based testing. We evaluated the strategies with six case studies and a total of 21 fitness combinations for each case study (i.e., a total of 126 problems). Our evaluation suggests that these strategies are indeed helpful for solving the multi-objective test case selection problem. In fact, two of the proposed seeding strategies outperformed the NSGA-II algorithm without seeding population with statistical significance for 92.8 and 96% of the problems.

Software systems that are embedded in autonomous Cyber-Physical Systems (CPSs) usually have a large life-cycle, both during its development and in maintenance. This software evolves during its life-cycle in order to incorporate new requirements, bug fixes, and to deal with hardware obsolescence. The current process for developing and maintaining this software is very fragmented, which makes developing new software versions and deploying them in the CPSs extremely expensive. In other domains, such as web engineering, the phases of development and operation are tightly connected, making it possible to easily perform software updates of the system, and to obtain operational data that can be analyzed by engineers at development time. However, in spite of the rise of new communication technologies (e.g., 5G) providing an opportunity to acquire Design-Operation Continuum Engineering methods in the context of CPSs, there are still many complex issues that need to be addressed, such as the ones related with hardware-software co-design. Therefore, the process of Design-Operation Continuum Engineering for CPSs requires substantial changes with respect to the current fragmented software development process. In this paper, we build a taxonomy for Design-Operation Continuum Engineering of CPSs based on case studies from two different industrial domains involving CPSs (elevation and railway). This taxonomy is later used to elicit requirements from these two case studies in order to present a blueprint on adopting Design-Operation Continuum Engineering in any organization developing CPSs.

Context: Software Product Line (SPL) testing is challenging mainly due to the potentially huge number of products under test. Most of the research on this field focuses on making testing affordable by selecting a representative subset of products to be tested. However, once the tests are executed and some failures revealed, debugging is a cumbersome and time consuming task due to difficulty to localize and isolate the faulty features in the SPL. Objective: This paper presents a debugging approach for the localization of bugs in SPLs. Method: The proposed approach works in two steps. First, the features of the SPL are ranked according to their suspiciousness (i.e., likelihood of being faulty) using spectrum-based localization techniques. Then, a novel fault isolation approach is used to generate valid products of minimum size containing the most suspicious features, helping to isolate the cause of failures. Results: For the evaluation of our approach, we compared ten suspiciousness techniques on nine SPLs of different sizes. The results reveal that three of the techniques (Tarantula, Kulcynski2 and Ample2) stand out over the rest, showing a stable performance with different types of faults and product suite sizes. By using these metrics, faults were localized by examining between 0.1% and 14.4% of the feature sets. Conclusion: Our results show that the proposed approach is effective at locating bugs in SPLs, serving as a helpful complement for the numerous approaches for testing SPLs

Sistema Ziber-Fisikoek sistema ziber digitalak sistema fisikoekin uztartzen dituzte. Sistema hauen aldakortasuna handitzen ari da erabiltzaileen hainbat behar betetzeko. Ondorioz, sistema ziber-fisikoa aldakorrak edota produktu lerroak ari dira garatzen eta sistema hauek milaka edo milioika konfiguraziotan konfiguratu daitezke. Sistema ziber-fisiko aldakorren test eta balidazioa prozesua garestia da, batez ere probatu beharreko konfigurazio kopuruaren ondorioz. Konfigurazio kopuru altuak sistemaren prototipo bat erabiltzea ezinezkoa egiten du. Horregatik, sistema ziber-fisiko aldagarriak simulazio modeloak erabilita probatzen dira. Hala ere, simulazio bidez sistema ziber-fisikoak probatzea erronka izaten jarraitzen du. Hasteko, simulazio denbora altua izaten da normalki, software-az aparte, sistema fisikoa simulatu behar delako. Sistema fisiko hau normalean modelo matematiko konplexuen bitartez modelatzen da, konputazionalki garestia delarik. Jarraitzeko, sistema ziber-fisikoek ingeniaritzaren domeinu ezberdinak dituzte tartean, adibidez mekanika edo elektronika. Domeinu bakoitzak bere simulazio erremienta erabiltzen du, eta erremienta guzti hauek interkonektatzeko ko-simulazioa erabiltzen da. Nahiz eta ko-simulazioa abantaila bat izan ematen duen flexibilitateagatik, simulagailu ezberdinen erabilerak simulazio denbora handiagotzen du. Azkenik, sistema ziber-fisikoak simulaziopean probatzean, probak maila ezberdinetan egin behar dira (adb., Model, Software eta Hardware-in-the-Loop mailak), eta honek, proba-kasuak exekutatzeko denbora handitzen du. Tesi honen helburua sistema ziber-fisiko aldakorren test jardunbideak hobetzea da, horretarako automatizazio, optimizazio eta arazketa metodoak proposatzen ditu. Automatizazioari dagokionez, lehenengo, erremienta-bidezko metodologia bat proposatzen da. Metodologia hau test sistema instantziak automatikoki sortzeko gai da, test sistema hauek sistema ziber-fisiko aldagarrien konfigurazioak automatikoki probatzeko gai dira (a, Los sistemas cyber-físicos (CPSs) integran tecnologías digitales con procesos físicos. La variabilidad de estos sistemas está creciendo para responder a la demanda de diferentes clientes. Como consecuencia de ello, los CPSs están volviéndose configurables e incluso líneas de producto, lo que significa que pueden ser configurados en miles y millones de configuraciones. El testeo de sistemas cyber-físicos configurables es un proceso costoso, en general debido a la cantidad de configuraciones que han de ser testeadas. El número de configuraciones a testear hace imposible el uso de un prototipo del sistema. Por ello, los sistemas CPSs configurables están siendo testeadas utilizando modelos de simulación. Sin embargo, el testeo de sistemas cyber-físicos bajo simulación sigue siendo un reto. Primero, el tiempo de simulación es normalmente largo, ya que, además del software, la capa física del CPS ha de ser testeada. Esta capa física es típicamente modelada con modelos matemáticos complejos, lo cual es computacionalmente caro. Segundo, los sistemas cyber-físicos implican el uso de diferentes dominios de la ingeniería, como por ejemplo la mecánica o la electrónica. Por ello, para interconectar diferentes herramientas de modelado y simulación hace falta el uso de la co-simulación. A pesar de que la co-simulación es una ventaja en términos de flexibilidad para los ingenieros, el uso de diferentes simuladores hace que el tiempo de simulación sea más largo. Por último, al testear sistemas cyberfísicos haciendo uso de simulación, existen diferentes niveles (p.ej., Model, Software y Hardware-in-the-Loop), lo cual incrementa el tiempo para ejecutar casos de test. Esta tesis tiene como objetivo avanzar en la práctica actual del testeo de sistemas cyber-físicos configurables, proponiendo métodos para la automatización, optimización y depuración. En cuanto a la automatización, primero, se propone una metodología soportada por una herramienta para generar automáticamente instancias de, Cyber-Physical Systems (CPSs) integrate digital cyber technologies with physical processes. The variability of these systems is increasing in order to give solution to the different customers demands. As a result, CPSs are becoming configurable or even product lines, which means that they can be set into thousands or millions of configurations. Testing configurable CPSs is a time consuming process, mainly due to the large amount of configurations that need to be tested. The large amount of configurations that need to be tested makes it infeasible to use a prototype of the system. As a result, configurable CPSs are being tested using simulation. However, testing CPSs under simulation is still challenging. First, the simulation time is usually long, since apart of the software, the physical layer needs to be simulated. This physical layer is typically modeled with complex mathematical models, which is computationally very costly. Second, CPSs involve different domains, such as, mechanical and electrical. Engineers of different domains typically employ different tools for modeling their subsystems. As a result, co-simulation is being employed to interconnect different modeling and simulation tools. Despite co-simulation being an advantage in terms of engineers flexibility, the use of different simulation tools makes the simulation time longer. Lastly, when testing CPSs employing simulation, different test levels exist (i.e., Model, Software and Hardware-in-the-Loop), what increases the time for executing test cases. This thesis aims at advancing the current practice on testing configurable CPSs by proposing methods for automation, optimization and debugging. Regarding automation, first, we propose a tool supported methodology to automatically generate test system instances that permit automatically testing configurations of the configurable CPS (e.g., by employing test oracles). Second, we propose a test case generation approach based on multi-objective search algorith

As systems evolve, their embedded software needs constantly to be refactored. Moreover, given the different needs of different customers, embedded systems require to be customizable. The variability of these systems is large, and requires automated testing solutions. In this paper we propose a methodology that automatically generates validation environments for highly configurable embedded software that is being refactored. The method has allowed for systematically testing a real-world industrial case study involving the software in charge of controlling the doors of an elevator. Finally, we extract the lessons learned from its application.

We extend the adiabatic regularization method to spin-1/2 fields. The ansatz for the adiabatic expansion for fermionic modes differs significantly from the WKB-type template that works for scalar modes. We give explicit expressions for the first adiabatic orders and analyze particle creation in de Sitter spacetime. As for scalar fields, the adiabatic method can be distinguished by its capability to overcome the UV divergences of the particle number operator. We also test the consistency of the extended method by working out the conformal and axial anomalies for a Dirac field in a Friedmann-Lemaitre-Robertson-Walker spacetime, in exact agreement with those obtained from other renormalization prescriptions. We finally show its power by computing the renormalized stress-energy tensor for Dirac fermions in de Sitter space.