Global controllability tests for geometric hybrid control systems

Hybrid systems are characterized by having an interaction between continuous dynamics and discrete events. The contribution of this paper is to provide hybrid systems with a novel geometric formulation so that controls can be added. Using this framework we describe some new global controllability tests for hybrid control systems exploiting the geometry and the topology of the set of jump points, where the instantaneous change of dynamics take place. Controllability is understood as the existence of a feasible trajectory for the system joining any two given points. As a result we describe examples where none of the continuous control systems are controllable, but the associated hybrid system is controllable because of the characteristics of the jump set.Comment: 27 pages, 5 figure

The voice of birth families to improve visits in foster care

In foster care, contact visits with birth families play an important role in relation to the child’s wellbeing, and they may impact on placement outcomes. However, the views of birth parents with respect to such visits have largely been unexplored. This research is part of a project financed by the regional government of Andalusia (SEJ-7106) regarding contact visits in foster care. This study aims to give voice to parents and gather their views about contact visits, including how they might be improved. Participants were 23 birth families who had contact visits with 35 children in non-kinship foster care. Semi-structured individual interviews were conducted in order to explore two key aspects: the parents’ opinions regarding the contact visits and the main areas they felt needed improving. The interviews were transcribed and the transcripts were examined using an inductive method of open coding to identify themes among participants’ responses. The main themes to emerge concerned their general view of contact visits and the organization of visits. The paper discusses the study’s implications of the findings for practice.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Efecto de la memoria de trabajo y la distancia anafórica en el procesamiento de anáforos pronominales en niños con trastorno específico del lenguaje

155 p.Los niños con trastorno específico del lenguaje (TEL) suelen presentar dificultades en diversos aspectos del discurso, tales como en los elementos de cohesión que marcan relaciones entre los textos. Los anáforos pronominales son una entidad discursiva que entregan cohesión y coherencia a un texto. El procesamiento de los anáforos pronominales puede ser afectado por una serie de factores. El propósito de este estudio es justamente identificar algunos de los factores que afectan el procesamiento de los anáforos pronominales en niños con TEL y determinar si existen diferencias entre estos niños y aquellos con desarrollo típico del lenguaje. En una muestra de 63 niños de edades comprendidas entre los 53,05 y 67,18 meses, divididos en 3 grupos, niños con TEL, niños típicos con misma edad cronológica y niños típicos con misma edad lingüística, se estudió el procesamiento de anáforos pronominales, considerando la distancia anafórica y la carga cognitiva como variables independientes. Los resultados indican que los niños con TEL presentan un rendimiento significativamente inferior al de los niños típicos con la misma edad cronológica y similar a los niños con misma edad lingüística. Además, el procesamiento de anáforos pronominales no es afectado por la carga cognitiva sino más bien por la distancia que existe entre el pronombre y su referente.Palabras claves: anáfora pronominal, distancia anafórica, carga cognitiva, trastorno específico del lenguaje./ABSTRACT:Children with specific language impairment (SLI) often have difficulties in various aspects of discourse, such as those cohesive elements that mark relations between texts. The pronominal anaphora is a discursive entity that gives cohesion and coherence to a text. Besides, the pronominal anaphora processing can be affected by a number of factors. The purpose of this study is precisely to identify some of the factors that affect the pronominal anaphora processing in children with SLI and identify if there are differences between groups. In a sample of 63 children aged between 53.05 and 67.18 months, divided into 3 groups, children with SLI, typical children with same chronological age and typical children with the same linguistic age, the pronominal anaphora processing was studied considering the anaphoric distance and cognitive load. The results indicate that children with SLI have significantly lower performance than typical children with same chronological age and similar to the children with same linguistic age, additionally the pronominal anaphora processing is not affected by cognitive load but rather by the distance between the pronoun and its referent. Keywords: pronominal anaphora, anaphoric distance, cognitive load, specific language impairmen

Remote teaching in construction engineering management during COVID-19

[EN] This paper describes the impact of the change from face-to-face classes to non-face-to-face classes with students of a postgraduate course at the Universitat Politècnica de València. This study is carried out in the subjects of installation, organization and quality assurance in construction and construction procedures of both degree in public works engineering and civil engineering. This course develops the student's skills to integrate into the studies department of a construction company, as Site Manager or Production Director, from a journey through the different phases of the project-construction process. As part of this topic, the methods of scheduling activities on site are discussed. In the traditional face to-face method, several problems are solved, requiring that students have previously learned programming techniques: arrow networks, precedence networks, and how to apply the PERT method to statistically obtain the probability of completion of a building or the completion of activities related. Due to the current situation of the pandemic caused by COVID-19, face-to-face teaching has changed virtual classes in a very short time. This has required a radical shift towards distance education. This paper explains how this change has been made, what new methods have been used to teach the contents corresponding to the scheduling of assignments, and what the students' perception has been. The quality of the education received and the difficulties encountered in obtaining the knowledge and skills attributed to this subject are analyzed.The authors acknowledge the support for the Ministry of Economy and Company and FEDER funding (Project BIA2017-85098-R).Martínez-Muñoz, D.; Martí Albiñana, JV.; Yepes, V. (2021). Remote teaching in construction engineering management during COVID-19. IATED Academy. 879-887. https://doi.org/10.21125/inted.2021.0205S87988

Steel-Concrete Composite Bridges: Design, Life Cycle Assessment, Maintenance, and Decision-Making

[EN] Steel-concrete composite bridges are used as an alternative to concrete bridges because of their ability to adapt their geometry to design constraints and the possibility of reusing some of the materials in the structure. In this review, we report the research carried out on the design, behavior, optimization, construction processes, maintenance, impact assessment, and decision-making techniques of composite bridges in order to arrive at a complete design approach. In addition to a qualitative analysis, a multivariate analysis is used to identify knowledge gaps related to bridge design and to detect trends in research. An additional objective is to make visible the gaps in the sustainable design of composite steel-concrete bridges, which allows us to focus on future research studies. *eresults of this work show how researchers have concentrated their studies on the preliminary design of bridges with a mainly economic approach, while at a global level, concern is directed towards the search for sustainable solutions. It is found that life cycle impact assessment and decision-making strategies allow bridge managers to improve decision-making, particularly at the end of the life cycle of composite bridges.This study was funded by the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (DIMALIFE Project BIA2017-85098-R).Martínez-Muñoz, D.; Martí Albiñana, JV.; Yepes, V. (2020). Steel-Concrete Composite Bridges: Design, Life Cycle Assessment, Maintenance, and Decision-Making. Advances in Civil Engineering. 2020:1-13. https://doi.org/10.1155/2020/8823370S113202

Application of the response surface methodology in a postgraduate optimization course

[EN] This paper describes the introduction of response surface methodology in a postgraduate course. This case study is carried out in the subject of the predictive models of optimization of concrete structures subject. This subject is inside the curricula of concrete engineering master. In this course students learn concepts such as structures¿ optimization using algorithms, multi-criteria decision making, techniques do design of experiments, and metamodels such as the response surface in order to obtain optimum results. In this case study, the objective is to obtain a design solution of a reinforced concrete wall, using the CO2 emissions as an objective function to reduce its impact. In order to apply this methodology, the students need to use specific software. On the one hand, to carry out the statistical analysis that allow obtaining the response surface Minitab software has been used by students. On the other hand, students need to check the strength of the structure using Cype structural calculation software. As a result of applying this methodology to obtain an optimum reinforced concrete wall allow students to reach a better level in transversal competencies, such as design and project, critical thinking, analysis and problem solving or the use of specific software. This paper will introduce future research studies related to the use of structures optimization techniques by students applying other different optimization techniques.The authors acknowledge the support for the Ministry of Economy and Company and FEDER funding (Project BIA2017-85098-R).Yepes, V.; Martínez-Muñoz, D.; Martí Albiñana, JV. (2021). Application of the response surface methodology in a postgraduate optimization course. IATED Academy. 869-878. https://doi.org/10.21125/inted.2021.0204S86987

Social Impact Assessment Comparison of Composite and Concrete Bridge Alternatives

[EN] The definition of sustainability includes three fundamental pillars: economic, environmental, and social. Studies of the economic impact on civil engineering infrastructures have been focused on cost reduction. It is not necessarily in line with economic sustainability due to the lack of other economic factors. Moreover, the social pillar assessment has been weakly developed compared to the economic and the environmental ones. It is essential to focus on the social pillar and evaluate clear indicators that allow researchers to compare alternatives. Furthermore, bridge life cycle assessment studies have been focused on concrete options. This has resulted in a lack of analysis of the impact of composite bridge alternatives. This study is conducted in two stages. The first part of the study makes a cradle-to-grave social and environmental sustainability evaluation with the SOCA v2 and ecoinvent v3.7.1 databases. This assessment is carried out on four concrete and composite bridge alternatives with span lengths between 15 and 40 m. The social impact weighting method and recipe have been used to obtain the social and environmental indicators. The second part of the study compares the results obtained from the social and environmental assessment of the concrete and the composite alternatives varying the steel recycling rate. The bridge alternatives are prestressed concrete solid slab, prestressed concrete lightened slab, prestressed concrete box-girder, and steel¿concrete composite box-girder. The results show that composite options are the best for environmental impact, but the concrete box girder solutions are better for social impact. Furthermore, an increase in the steel recycling rate increases the social impact and decreases the environmental one.This research was funded by: Grant PID2020-117056RB-I00 funded byMCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe". Grant FPU-18/01592 funded by MCIN/AEI/10.13039/501100011033 and by "ESF invests in your future".Martínez-Muñoz, D.; Martí Albiñana, JV.; Yepes, V. (2022). Social Impact Assessment Comparison of Composite and Concrete Bridge Alternatives. Sustainability. 14(9):1-19. https://doi.org/10.3390/su1409518611914

Comparative Life Cycle Analysis of Concrete and Composite Bridges Varying Steel Recycling Ratio

[EN] Achieving sustainability is currently one of the main objectives, so a consensus between different environmental, social, and economic aspects is necessary. The construction sector is one of the main sectors responsible for environmental impacts worldwide. This paper proposes the life cycle assessment (LCA) and comparison of four bridge deck alternatives for different span lengths to determine which ones are the most sustainable solutions. The ReCiPe method is used to conduct the life cycle analysis, by means of which the impact value is obtained for every alternative and span length. The Ecoinvent 3.3 database has been used. The life cycle has been divided into four phases: manufacturing, construction, use and maintenance, and end of life. The associated uncertainties are considered, and the results are shown in both midpoint and endpoint approaches. The results of our research show that for span lengths less than 17 m, the best alternative is the prestressed concrete solid slab. For span lengths between 17 and 25 m, since the box-girder solution is not used, then the prestressed concrete lightened slab is the best alternative. For span lengths between 25 and 40 m, the best solution depends on the percentage of recycled structural steel. If this percentage is greater than 90%, then the best alternative is the composite box-girder bridge deck. However, if the percentage is lower, the cleanest alternative is the prestressed concrete box-girder deck. Therefore, the results show the importance of recycling and reusing structural steel in bridge deck designs.This research was funded by Spanish Ministry of Economy and Business (Project: BIA201785098-R), the Spanish Ministry of Science and Innovation (Project: PID2020-117056RB-I00), along with FEDER funding and Spanish Ministry of Science, Innovation and Universities for David MartinezMunoz's University Teacher Training Grant (FPU-18/01592).Martínez-Muñoz, D.; Martí Albiñana, JV.; Yepes, V. (2021). Comparative Life Cycle Analysis of Concrete and Composite Bridges Varying Steel Recycling Ratio. Materials. 14(15):1-22. https://doi.org/10.3390/ma14154218S122141

Exciton Gas Compression and Metallic Condensation in a Single Semiconductor Quantum Wire

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidences of metallic liquid condensation at low temperatures. Firstly, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Secondly, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at $n_c\sim1\times10^5$ cm$^{-1}$ and $T_c\sim35$ K, respectively.Comment: 4 pages, 5 figure