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Influences of Cutting Speed and Material Constitutive Models on Chip Formation and their Effects on the Results of Ti6Al4V Orthogonal Cutting Simulation
Full text linkThe highly used Ti6Al4V alloy is a well know hard-to-machine material. The modelling of orthogonal cutting process of Ti6Al4V attract the interest of many researchers as it often generates serrated chips. The purpose of this paper is to show the significant influence of cutting speed on chip formation during orthogonal cutting of Ti6Al4V along with different material constitutive models. Finite element analyses for chip formation are conducted for different cutting speeds and are investigated with well-known Johnson-Cook constitutive model, a modified Johnson–Cook model known as Hyperbolic Tangent (TANH) model that emphasizes the strain softening behavior and modified Johnson-Cook constitutive model that consider temperature dependent strain hardening factor. A 2D Lagrangian finite element model is adopted for the simulation of the orthogonal cutting process and the results from the simulations such as calculated forces, chip morphologies are analyzed and are compared with the experimental results to highlight the differences. The results analysis shows that, the temperature in the secondary deformation zone is directly proportional to the cutting speed
Human‑centred design in industry 4.0: case study review and opportunities for future research
Full text linkThe transition to industry 4.0 has impacted factories, but it also afects the entire value chain. In this sense, human-centred factors play a core role in transitioning to sustainable manufacturing processes and consumption. The awareness of human roles in Industry 4.0 is increasing, as evidenced by active work in developing methods, exploring infuencing factors, and proving the efectiveness of design oriented to humans. However, numerous studies have been brought into existence but then disconnected from other studies. As a consequence, these studies in industry and research alike are not regularly adopted, and the network of studies is seemingly broad and expands without forming a coherent structure. This study is a unique attempt to bridge the gap through the literature characteristics and lessons learnt derived from a collection of case studies regarding human-centred design (HCD) in the context of Industry 4.0. This objective is achieved by a well-rounded systematic literature review whose special unit of analysis is given to the case studies, delivering contributions in three ways: (1) providing an insight into how the literature has evolved through the cross-disciplinary lens; (2) identifying what research themes associated with design methods are emerging in the feld; (3) and setting the research agenda in the context of HCD in Industry 4.0, taking into account the lessons learnt, as uncovered by the in-depth review of case studies
Experiencia colectiva de aplicación de la clase invertida en el grado de informática
Full text linkAs information consumption habits change, higher education is facing the challenge of transforming the teaching experience in order to maximize student involvement and motivation. This transformation, based on multimedia content and the continuous control of knowledge acquisition by students, has been accelerated by the forced digitalisation caused by the Covid19
pandemic. Among the different paradigms, the inverted class is one of the most studied and relevant transformation alternatives. This work presents the preliminary results of a case study of an implementation at scale of the inverted classroom -in twelve subjects from different academic courses- in a computer engineering degree during the 2020/21 academic year. The main motivation behind the transformation is presented, how the resources and training of the teaching staff have been enabled, the teaching methodology applied (focused on multimedia content and control of the concepts acquired) and the evaluation of the obtained results. For the evaluation, surveys specifically designed for the involved teaching staff and students have been carried out.Con el cambio de los hábitos de consumo de información, la educación superior se encuentra frente al desafío de transformar la experiencia docente de cara a maximizar la implicación y motivación del alumnado. Dicha transformación, basada en contenidos multimedia y en el control continuo de adquisición de conocimientos por parte del alumnado, se ha acelerado por la digitalización forzada provocada por la pandemia Covid19. De los diferentes paradigmas, la clase invertida toma fuerza como una de las alternativas transformadoras más estudiadas y relevantes. Este trabajo presenta los resultados preliminares de un caso de estudio de una implantación del aula invertida a escala -en doce asignaturas de diferentes cursos- en un grado de ingeniería informática durante el curso 2020/21. Se expone la principal motivación detrás de la transformación, la capacitación de recursos y formación del profesorado, la metodología docente aplicada (centrada en el contenido multimedia y el control de los conceptos adquiridos) y la evaluación de los resultados obtenidos. Para la evaluación, se han realizado encuestas específicamente diseñadas al profesorado y alumnado involucrado
Industria eolikoko palen efizientzia aerodinamikoaren azterketa esperimentala baldintza ideal eta errealetan
Full text linkThe paradigm of renewable energies brings a number of challenges to be solved in a short-term period. In the case of wind energy, it turns necessary to relocate onshore wind-farms in both offshore coastal regions and urban environments, so that visual and environmental impacts of current devices are reduced. This modifies the flow regime noticeably; indeed, turbulence and environmentally-induced roughness need to be accounted for, in addition to the scale-effect in case of urban wind turbines. The effects of such factors on the aerodynamic efficiency of a standard NACA0021 airfoil are tested via wind-tunnel measurements, showing the resultant decrease in aerodynamic efficiency when passing from ideal to real flow conditions. Such a decrease leads to concluding that aerodynamic tests should be undertaken with flow configurations that represent real operational conditions.Energia berriztagarrien paradigmak erronka ugari dakartza berorrekin, epe laburrean erantzun beharrekoak bederen. Energia eolikoaren kasuan, ustiapena ohiko haize-parkeetatik itsasalde edota hiriguneetara mugitzean datza, inpaktu bisuala nahiz ingurumen kalteak murrizteko asmoz. Horrek haizearen fluxu baldintzak nabarmen aldatzea dakar; bereziki, turbulentzia eta ingurumen-eragileek sorturiko gainazal-zimurtasuna hartu behar da kontuan eta, hiriguneetako kasuan, aerosorgailuen eskala aldaketa. Haize-tunel bidezko entseguak burutuz, faktore horiek NACA0021 geometriadun pala baten efizientzia aerodinamikoan duten eragina aztertu da, baldintza idealetatik errealetara igarotzean ematen den efizientzia galera ikusaraziz. Galera hori dela-eta, entsegu esperimentalak harik eta baldintza errealenetan egiteko beharra ondorioztatzen da
Web Augmentation as a Technique to Diminish User Interactions in Repetitive Tasks
Full text linkThe use of the World Wide Web has experienced extraordinary growth in the last decades. The Web has become the main source of information for millions of users. The number of websites offering content to users is countless. In order to personalise information according to their needs, users often have to visit multiple, unconnected pages. Users perform a number of actions to collect that information that requires concentration. If the number of Web resources is large, the activity becomes unpleasant. The problem increases when these tasks are performed frequently and repetitively. These tasks are time-consuming and lead users to experience frustration and disorientation during the activity, causing a loss of concentration that prolongs the activity over time. Web Augmentation combines different Web technologies to improve user experience on existing pages by adding content from different pages among other benefits. This article proposes Web Augmentation as a technique to reduce user interactions in repetitive tasks. To support the proposal, the paper introduces Excore, a browser extension for Web Augmentation that allows end-users to add content from different resources automatically. The article presents the benefits introduced by this approach as a response to the drawbacks experienced by users while performing their activities on the Web. The architecture of the platform and its operations are described by means of an example. A double evaluation of the extension is addressed, one qualitative and one quantitative. The results show that Excore reduces the number of interactions by 94.45% and the time to complete a task by 80.75%
Model-Based Testing in Practice: An Industrial Case Study using GraphWalker
Full text linkModel-based testing (MBT) is a test design technique that supports the automation of software testing processes and generates test artefacts based on a system model representing behavioural aspects of the system under test (SUT). Previous
research has shown some positive aspects of MBT such as low-cost test case generation and fault detection effectiveness. However, it is still a challenge for both practitioners and researchers to evaluate MBT tools and techniques in real, industrial settings. Consequently, the empirical evidence regarding the mainstream use, including the modelling and test case generation using MBT tools, is limited. In this paper, we report the results of a case study on applying GraphWalker, an open-source tool for MBT, on an industrial cyber-physical system (i.e., a Train Control Management System developed by Bombardier Transportation in Sweden), from modelling of real-world requirements and test specifications to test case generation. We evaluate the models of the SUT for completeness and representativeness, compare MBT with manual test cases written by practitioners using multiple attributes as well as share our experiences of selecting and using GraphWalker for industrial application. The results show that a model of the SUT created using both requirements and test specifications provides better understanding of the SUT from testers’ perspective, making it more complete and representative than the model created based only on the requirements specification alone. The generated model-based test cases are longer in terms of the number of test steps, achieve better edge coverage and can cover requirements more frequently in different orders while achieving the same level of requirements coverage as manually created test cases
New drawbead tester and numerical analysis of drawbeads closure force
Full text linkCurrently, a great deal of controversy exists regarding the real forces generated in drawbeads during sheet metal forming processes. The present work focuses on the analysis of the uplift force. First, a detailed literature review is carried out to analyse previous experimental procedures used to measure uplift forces. It is found that previous setups do not perfectly replicate the real geometry of industrial drawbeads. In order to obtain reliable forces, an experimental drawbead tester capable of adequately replicating industrial drawbeads is developed. Later, a variety of steels ranging from mild steels to 3rd-generation ultra-highstrength steels are tested and reliable uplift and also restraining force values are obtained. The main purpose of the work is to share with the research community reliable experimental data that allows precise evaluation of the accuracy of current drawbead models and that supports the generation of new numerical and equivalent drawbead models. In parallel to the experimental procedure, a step forward in the understanding of the drawbead closing phenomena is also achieved through a 2D numerical model. The main purpose of the model is to identify the variables that greatly affect uplift force. Going beyond previous studies, in which some variables were analysed, the present work covers, in a holistic manner, the impact that material properties, the geometry of drawbeads and contact behaviour between sheet and drawbead have on the uplift force. It is determined that surprisingly minor geometrical deviations in the drawbead nominal geometry have a large impact on the uplift force
Percepciones del profesorado universitario y de futuros docentes hacia un modelo híbrido. El caso de la Facultad de Humanidades y Ciencias de la Educación de Mondragon Unibertsitatea
No full textLa crisis provocada por la COVID-19 ha promovido que los entornos tanto online como híbridos
adquieran un gran protagonismo en todas las etapas del sistema educativo. Este desafío ha suscitado
la visibilización de retos relacionados con la competencia digital del profesorado en general y los
conocimientos sobre el diseño tecnopedagógico en particular. Sin embargo, las percepciones del
profesorado juegan un rol esencial en la respuesta de las instituciones a los nuevos retos. La
investigación que se presenta en este artículo se enmarca en ese contexto y tiene como objetivo
analizar las percepciones tanto de los estudiantes del Grado de Educación Primaria (n=89) como
los docentes del mismo (n=24) hacia el modelo híbrido implantado. Los resultados obtenidos de
las encuestas diseñadas ad-hoc muestran que los participantes valoran la implementación del
modelo híbrido de forma positiva. Sin embargo, el alumnado ha identificado cuatro elementos
particulares del modelo híbrido que parecen influir en el proceso de enseñanza-aprendizaje: la
narrativa, la integración de contextos, la sincronía y el feedback.The crisis caused by COVID-19 has fostered online and hybrid environments to play a paramount
role in all educational stages. This situation has also promoted the visibility of challenges related to
the digital competence of teachers and knowledge about techno-pedagogical design. However,
teachers' perceptions still play an essential role in the response of institutions to new challenges.
The research presented in this article is framed in this context and aims to analyze the perceptions
of both the teacher students enrolled in Primary Education Degree (n= 89) and teachers of Degree
(n= 24) towards the implanted hybrid model. The results obtained from the ad-hoc designed
questionnaire show that the participants value the implementation of the hybrid model positively.
However, four aspects of the hybrid model have been identified that seem to influence the
teaching-learning process: narrative, context integration, synchrony, and feedback
Petri net-based semi-compiled code generation for programmable logic controllers
Full text linkIndustrial discrete event dynamic systems (DEDSs) are commonly modeled by means of Petri nets (PNs). PNs have the capability to model behaviors such as concurrency, synchronization, and resource sharing, compared to a step transition function chart or GRAphe Fonctionnel de Commande Etape Transition (GRAFCET) which is a particular case of a PN. However, there is not an effective systematic way to implement a PN in a programmable logic controller (PLC), and so the implementation of such a controller outside a PLC in some external software that will communicate with the PLC is very common. There have been some attempts to implement PNs within a PLC, but they are dependent on how the logic of places and transitions is programmed for each application. This work proposes a novel application-independent and platform-independent PN implementation methodology. This methodology is a systematic way to implement a PN controller within industrial PLCs. A great portion of the code will be validated automatically prior to PLC implementation. Net structure and marking evolution will be checked on the basis of PN model structural analysis, and only net interpretation will be manually coded and error-prone. Thus, this methodology represents a systematic and semi-compiled PN implementation method. A use case supported by a digital twin (DT) is shown where the automated solution required by a manufacturing system is carried out and executed in two different devices for portability testing, and the scan cycle periods are compared for both approaches
Derrigorrezko Bigarren Hezkuntzara bideratutako STEM proiektuen azterketa kuantitatiboa
Full text linkEgungo ikasleek STEM (Science, Technology, Engineering, Mathematics) diziplinetan eta
lanbideetan aurkezten duten interes eta motibazio baxua mundu mailako kezka bihurtu da. Euskal
hezkuntza-sistemak duen erronka handia da: ikasleek STEM diziplinen konpetentziak bereganatzen
dituztela ziurtatzea; aurrerapen zientifiko-teknologiko-digitalez beteriko mundu honetan, STEM
lanbideen garrantzia handituz baitoa. Ikerketa honetan, hizkuntza anitzeko 108 STEM proiektuen
nolakotasuna analizatu da, Derrigorrezko Bigarren Hezkuntza etapara bideratutako eta euskaraz
diseinatutako proiektuetan arreta berezia jarriz. Ikerketaren emaitzei esker, etorkizunean euskaraz
diseinatuko diren proiektuek bete beharko lituzketen irizpideak zehaztu dira, ekarpen gisa.The low interest and motivation of today's students in STEM (Science, Technology, Engineering and
Mathematics) subjects and trades has become a worldwide concern. The Basque education system faces
a great challenge: to make students competent in STEM disciplines, because the importance of STEM
trades are increasing in a world full of scientific-technological-digital advances. This research shows
the results of the analysis of 108 multilingual STEM projects, paying special attention to projects
designed in Basque for the Compulsory Secondary Education stage. The results of the research have
made possible to define, as a contribution, the criteria that should be met in the future by projects
designed in Basque