A methodology for economic evaluation of cloud-based web applications

[EN] Cloud technology is an attractive infrastructure solution to optimize the scalability and performance of web applications. The workload of these applications typically fluctuates between peak and valley loads and sometimes in an unpredictable way. Cloud systems can easily deal with this fluctuation because they provide customers with an almost unlimited on-demand infrastructure capacity using a pay-per-use model, which enables internet-based companies to pay for the actual consumption instead of peak capacity. In this paradigm, this paper links the business model of an internet-based company to the performance evaluation of the infrastructure. To this end, the paper develops a new methodology for assessing the costs and benefits of implementing web-based applications in the cloud. Traditional performance models and indexes related to usage of the main system resources (such as processor, memory, storage, and bandwidth) have been reformulated to include new metrics (such as customer losses and service costs) that are useful for business managers. Additionally, the proposed methodology has been illustrated with a case study of a typical e-commerce scenario. Experimental results show that the proposed metrics enable internet-based companies to estimate the cost of adopting a particular cloud configuration more accurately in terms of the infrastructure cost and the cost of losing customers due to performance degradation. Consequently, the methodology can be a useful tool to assess the feasibility of business plans.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness under Grant TIN2013-43913-R.Domenech, J.; Peña Ortiz, R.; Gil, JA.; Pont Sanjuan, A. (2016). A methodology for economic evaluation of cloud-based web applications. International Journal of Information Technology and Decision Making. 15(6):1555-1578. https://doi.org/10.1142/S021962201650036XS1555157815

The impact of User-Browser Interaction on web performance

© ACM 2013. This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in ACM, In Proceedings of the 28th Annual ACM Symposium on Applied Computing (pp. 695-702). http://dx.doi.org/10.1145/2480362.2480497The user interaction with the current web contents is a major concern when defining web workloads in order to precisely estimate system performance. However, the intrinsic diffi- culty to represent this behavior in a workload model leads many research works to still use workloads non representative of the current web navigations. In contrast, in previous works we demonstrated that the use of an accurate workload model that considers user’s dynamism when navigating the web clearly affects system performance metrics. In this paper we analyze, for the first time, the effect of considering the User-Browser Interaction (UBI) as a part of user’s dynamic behavior on web workload characterization in performance studies. To this end, we evaluate a typical e-commerce scenario and compare the obtained results for different UBI behaviors, such as the use of the back button and parallel browsing originated by using browser tabs or opening new windows when surfing a website.This work has been partially supported by the Spanish Ministry of Science and Innovation under grant TIN-2009-08201.Peña Ortiz, R.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2013). The impact of User-Browser Interaction on web performance. ACM. https://doi.org/10.1145/2480362.2480497

GSaaS: A service to cloudify and schedule GPUs

Cloud technology is an attractive infrastructure solution that provides customers with an almost unlimited on-demand computational capacity using a pay-per-use approach, and allows data centers to increase their energy and economic savings by adopting a virtualized resource sharing model. However, resources such as graphics processing units (GPUs), have not been fully adapted to this model. Although, general-purpose computing on graphics processing units (GPGPU) is becoming more and more popular, cloud providers lack of flexibility to manage accelerators, because of the extended use of peripheral component interconnect (PCI) passthrough techniques to attach GPUs to virtual machines (VMs). For this reason, we design, develop, and evaluate a service that provides a complete management of cloudified GPUs (cGPUs) in public cloud platforms. Our solution enables an effective, anonymous, and transparent access from VMs to cGPUs that are previously scheduled and assigned by a full resource manager, taking into account new GPU selection policies and new working modes based on the locality of the physical accelerators and the exclusivity when accessing them. This easy-to-adopt tool improves the resource availability through different cGPUs configurations for end-users, whilst cloud providers are able to achieve a better utilization of their infrastructures and offer more competitive services. Scalability results in a real cloud environment demonstrate that our solution introduces a virtually null overhead in the deployment of VMs. Besides, performance experiments reveal that GPU-enabled clusters based on cloud infrastructures can benefit from our proposal not only exploiting better the accelerators, but also serving more jobs requests per unit of time

Analyzing web server performance under dynamic user workloads

The increasing popularity of web applications has introduced a new paradigm where users are no longer passive web consumers but they become active contributors to the web, specially in the contexts of social networking, blogs, wikis or e-commerce. In this new paradigm, contents and services are even more dynamic, which consequently increases the level of dynamism in user's behavior. Moreover, this trend is expected to rise in the incoming web. This dynamism is a major adversity to define and model representative web workload, in fact, this characteristic is not fully represented in the most of the current web workload generators. This work proves that the web user's dynamic behavior is a crucial point that must be addressed in web performance studies in order to accurately estimate system performance indexes. In this paper, we analyze the effect of using a more realistic dynamic workload on the web performance metrics. To this end, we evaluate a typical e-commerce scenario and compare the results obtained using different levels of dynamic workload instead of traditional workloads. Experimental results show that, when a more dynamic and interactive workload is taken into account, performance indexes can widely differ and noticeably affect the stress borderline on the server. For instance, the processor usage can increase 30% due to dynamism, affecting negatively average response time perceived by users, which can also turn in unwanted effects in marketing and fidelity policies. © 2012 Elsevier B.V. All rights reserved.This work has been partially supported by the Spanish Ministry of Science and Innovation under Grant TIN-2009-08201.Peña Ortiz, R.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2013). Analyzing web server performance under dynamic user workloads. Computer Communications. 36(4):386-395. https://doi.org/10.1016/j.comcom.2012.11.005S38639536

Interaction in spoken academic discourse in an EMI context: the use of questions

Studies on metadiscourse (Hyland 2005) have focussed on engagement as interaction. An example of engagement is asking questions (Hyland 2009: 112) and indeed the importance of questioning for content learning has been researched extensively in pedagogical studies as fundamental in co-constructing meaning (Dafouz Milne &amp; Sanchez Garcia 2013: 130). Research in an English Mediated Instruction (EMI) context found that teachers’ usage of questions in the classroom was affected by low levels of language competence and in these cases, strategies such as questioning could easily be underused or even misused, thus affecting the teaching and learning of content (Drljaca Margic &amp; Vodopija-Krstanovic 2018: 32). Our study examines lecturer questioning at an Italian University by triangulating face-to-face surveys of lecturers, student questionnaires, and transcribed lecture recordings. Findings have practical applications for providing targeted coaching for non-native EMI lecturers with regard to appropriate linguistic strategies to encourage interaction, and also have implications for research into linguistic strategies used within EMI. Normal 0 false false false EN-GB X-NONE X-NONE <w:LsdException Locked="falseJohnson, JH.; Picciuolo, M. (2020). Interaction in spoken academic discourse in an EMI context: the use of questions. En 6th International Conference on Higher Education Advances (HEAd'20). Editorial Universitat Politècnica de València. (30-05-2020):211-219. https://doi.org/10.4995/HEAd20.2020.11018OCS21121930-05-202

vylnoviolencia.uv.es: trabajo fin de máster en TIC aplicado a una experiencia ApS en Humanidades Digitales

En el camino hacia una sociedad tolerante e igualitaria, en la que se respeten los derechos y libertades fundamentales y de igualdad entre hombres y mujeres, resulta esencial una implicación efectiva de la comunidad universitaria, en su conjunto, en la reflexión crítica y en el desarrollo de acciones concretas. Alineado con este reto, «Voces y letras contra la violencia: imaginarios literarios y creación en videoarte» es un proyecto de innovación docente que apuesta por la aplicación de la metodología aprendizaje-servicio al ámbito de las Humanidades Digitales para afianzar el compromiso ético del alumnado con el respeto, la no violencia, la igualdad y la solidaridad como principios fundamentales en la convivencia. Este artículo describe los resultados obtenidos por el trabajo fin de máster bajo el cual se ha desarrollado la plataforma digital distribuida que relaciona videoarte y literatura en el proyecto.With the aim of achieving a tolerant and egalitarian society, which respects basic human rights and especially the right of equality between men and women, is essential an effective involvement of the university community, as a whole, in critical reflection and by developing specific actions. Aligned with this challenge, a teaching innovation project, named «Voces y letras contra la violencia: imaginarios literarios y creación en videoarte», is committed to the application of service-learning methodology in Digital Humanities to strengthen the students commitment to respect, nonviolence, equality and solidarity as fundamental principles in coexistence. This paper describes the results of a master’s thesis under which a distributed digital platform has been developed to link video art and literature related to the project

Using Virtual Reality to promote pre-service teachers’ classroom management skills and teacher resilience: A qualitative evaluation

[EN] Many novice teachers have difficulties in selecting and applying effective classroom management strategies to prevent or diminish disruptive behaviors. Negative experiences with classroom management largely determine teacher wellbeing and early attrition. Therefore, more in-training opportunities are needed to prepare prospective teachers to manage complex classroom practices effectively. A Virtual Reality-environment seems promising in developing classroom management skills and promoting teacher resilience; however, its potential is influenced by students’ perceptions towards this technology. This study describes four pre-service teachers’ and six school-based teacher educators’ experiences with and perceptions towards the use of a Virtual Reality learning environment to train classroom management skills and promote teacher resilience. Responses of semi-structured interviews reflect five themes: software- and equipment-related issues; feedback cues; realism and authenticity; instructor proficiency; and added value for teacher training. Results show that, for most themes, pre-service teachers and school-based teacher educators raised similar remarks and/or suggestions for improvement; however, they differed in their perceptions towards the added value of Virtual Reality to teacher training curricula. Our study highlights teachers’ needs for highly authentic and realistic simulations aligned with real-life classrooms and presents recommendations to augment the immersive experience needed for teachers to develop effective CMS and become more resilient.Mouw, J.; Fokkens-Bruinsma, M.; Verheij, G. (2020). Using Virtual Reality to promote pre-service teachers’ classroom management skills and teacher resilience: A qualitative evaluation. En 6th International Conference on Higher Education Advances (HEAd'20). Editorial Universitat Politècnica de València. (30-05-2020):325-332. https://doi.org/10.4995/HEAd20.2020.11049OCS32533230-05-202

Surfing the web using browser interface facilities: a performance evaluation approach

[EN] The user interaction with the current web contents is a major concern when defining web workloads in order to precisely estimate system performance. However, the intrinsic difficulty to represent this dynamic behavior with a workload model has caused that many research studies are still using non representative workloads of the current web navigations. In contrast, in previous works we demonstrated that the use of an accurate workload model which considers user s dynamism when navigating the web clearly affects system performance metrics. In this paper we analyze, for the first time, the effect of considering the User-Browser Interaction as a part of user s dynamic behavior on web workload characterization in performance studies. To this end, we evaluate a typical e-commerce scenario and compare the obtained results for different behaviors that take the user interaction into account, such as the use of the back button and parallel browsing originated by using browser tabs or opening new windows when surfing a website. Experimental results show that these interaction patterns allow users to achieve their navigation objectives sooner, so increasing their productivity up to 200% when surfing the Web. In addition, results prove that when this type of navigations is taken into account, performance indexes can widely differ and relax the stress borderline of the server. For instance, the server utilization drops as much as 45% due to parallel browsing behavior.This work has been partially supported by the Spanish Ministry Economy and Competitiveness under grant TIN-2013-43913-R.Peña Ortiz, R.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2015). Surfing the web using browser interface facilities: a performance evaluation approach. Journal of Web Engineering. 14(1-2):3-21. http://hdl.handle.net/10251/63834321141-

Providing TPC-W with web user dynamic behavior

The evolution of the World Wide Web from hypermedia information repositories to web applications such as social networking, wikis or blogs has introduced a new paradigm where users are no longer passive web consumers. Instead, users have become active contributors to web applications, so introducing a high level of dynamism in their behavior. Moreover, this trend is even expected to rise in the incoming Web. As a consequence, there is a need to develop new software tools that consider user dynamism in an appropiate and accurate way when generating dynamic workload for evaluating the performance of the current and incoming web. This paper presents a new testbed with the ability of defining and generating web dynamic workload for e-commerce. For this purpose, we integrated a dynamic workload generator (GUERNICA) with a widely used benchmark for e-commerce (TPC-W).Peña Ortiz, R.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2012). Providing TPC-W with web user dynamic behavior. CLEI Electronic Journal. 15(2):1-12. http://hdl.handle.net/10251/44074S11215

La lúdica y las TIC en educación física liceo técnico comercial LITECOM

Esta tesis tiene como principal objetivo descubrir el tratamiento que deben tener LA lúdica integrada a las TIC en la Educación Física en la institución educativa técnica comercial LITECOM. De este modo, se persigue presentar una propuesta didáctica que aborde las posibilidades que se pueden tener en la virtualización para la enseñanza de esta área de manera divertida para que los estudiantes afiancen los conocimientos y aprendizajes trabajados en clase y además aprovechen su tiempo libre de una manera lúdica