Search results for "RJ"
showing 10 items of 6589 documents
Teletraffic Engineering for Direct Load Control in Smart Grids
2018
International audience; The traditional paradigm for power grid operation is to continuously adapt energy production to demand. This paradigm is challenged by the increasing penetration of renewable sources, that are more variable and less predictable. An alternative approach is the direct load control of some inherently flexible electric loads to shape the demand. Direct control of deferrable loads presents analogies with flow admission control in telecommunication networks: a request for network resources (bandwidth or energy) can be delayed on the basis of the current network status in order to guarantee some performance metrics. In this paper we go beyond such an analogy, showing that u…
Dual Capability EAM for Agility in Business Capability Building : A Systems Theoretical View
2021
Through two cases of IT-enabled business capability building in large enterprises, this paper elucidates how the systems theory approach can explain the enterprise architecture management (EAM) challenge to support business agility. The observation in both of these cases is that a legacy EAM approach does not adapt to a business development scenario involving agility. This leads to a study of the nature of the challenges in EAM when enabling strategic business moves involving new technologies, at the business unit level. For the type of projects as in these cases, we do not find a fitting paradigm in the EAM literature. Suggested solutions are IT bimodality, or Two Speed IT. However, its co…
A stacked interleaved DC-DC buck converter for proton exchange membrane electrolyzer applications: Design and experimental validation
2019
Abstract Since the two last decades, hydrogen production has been attracting the attention of the scientific community thanks to its inherent very low pollution when energy coming from renewable energy sources (RESs) are used. However, it implies the use of DC/DC converters to interface source and load. These conversion systems must meet several requirements from current ripple point of view, energy efficiency, and performance to preserve the sustainability of hydrogen production. This article proposes the design and realization of a stacked interleaved buck converter to supply a proton exchange membrane electrolyzer. The converter is designed to ensure a low output current ripple and a sui…
Watch This! The Influence of Recommender Systems and Social Factors on the Content Choices of Streaming Video on Demand Consumers
2021
Streaming Video-on-demand (SVOD) services are getting increasingly popular. Current research, however, lacks knowledge about consumers’ content decision processes and their respective influencing factors. Thus, the work reported on in this paper explores socio-technical interrelations of factors impacting content choices in SVOD, examining the social factors WOM, eWOM and peer mediation, as well as the technological influence of recommender systems. A research model based on the Theory of Reasoned Action and the Technology Acceptance Model was created and tested by an n = 186 study sample. Results show that the quality of a recommender system and not the social mapping functionality is the …
Listwise Recommendation Approach with Non-negative Matrix Factorization
2018
Matrix factorization (MF) is one of the most effective categories of recommendation algorithms, which makes predictions based on the user-item rating matrix. Nowadays many studies reveal that the ultimate goal of recommendations is to predict correct rankings of these unrated items. However, most of the pioneering efforts on ranking-oriented MF predict users’ item ranking based on the original rating matrix, which fails to explicitly present users’ preference ranking on items and thus might result in some accuracy loss. In this paper, we formulate a novel listwise user-ranking probability prediction problem for recommendations, that aims to utilize a user-ranking probability matrix to predi…
Human digital twins and cognitive mimetic
2021
Digital twins – digital models of technical systems and processes – have recently been introduced to work with complex industrial processes. Yet should such models concern only physical objects (as definitions of them often imply), or should users and other human beings also be included? Models that include people have been called human digital twins (HDTs); they facilitate more accurate analyses of technologies in practical use. The cognitive mimetic approach can be used to describe human interactions with technologies. This approach analyses human information processes such as perceiving and thinking to mimic how people process information in order to design intelligent technologies. The …
Vectors of Pairwise Item Preferences
2019
Neural embedding has been widely applied as an effective category of vectorization methods in real-world recommender systems. However, its exploration of users’ explicit feedback on items, to create good quality user and item vectors is still limited. Existing neural embedding methods only consider the items that are accessed by the users, but neglect the scenario when a user gives high or low rating to a particular item. In this paper, we propose Pref2Vec, a method to generate vector representations of pairwise item preferences, users and items, which can be directly utilized for machine learning tasks. Specifically, Pref2Vec considers users’ pairwise item preferences as elementary units. …
Building a Maturity Model for Developing Ethically Aligned AI Systems
2021
Ethical concerns related to Artificial Intelligence (AI) equipped systems are prompting demands for ethical AI from all directions. As a response, in recent years public bodies, governments, and companies have rushed to provide guidelines and principles for how AI-based systems are designed and used ethically. We have learned, however, that high-level principles and ethical guidelines cannot be easily converted into actionable advice for industrial organizations that develop AI-based information systems. Maturity models are commonly used in software and systems development companies as a roadmap for improving the performance. We argue that they could also be applied in the context of develo…
Informal learning contexts in the construction of physical education student teachers’ professional identity
2022
This study aimed to investigate the significance of informal learning contexts in physical education (PE) student teachers’ professional identity construction. It addressed two research questions: How do informal learning contexts contribute to the construction of PE student teachers’ professional identity? What forms of relationships can be identified between the informal and formal contexts of learning in PE student teachers’ professional identity construction? The data consisted of 20 semi-structured interviews with PE student teachers during the final teaching practice period. The data were analysed using structural and pattern coding methods. The analysis revealed that informal learnin…
Angiomas en penacho en la infancia. Serie de 9 casos y revisión de la literatura
2015
Resumen: Introducción: El angioma en penacho o tufted angioma (TA) es una tumoración vascular benigna poco frecuente, que suele aparecer en la infancia, aunque existen casos de aparición en la edad adulta. Su presentación clínica es muy variable. Se manifiesta típicamente como una mácula, pápula o nódulo eritematovioláceo en el tronco o el cuello. Histológicamente, se caracteriza por agregados de lóbulos angiomatosos en la dermis formando pequeños penachos de capilares. Pacientes y métodos: Estudio retrospectivo observacional de los casos diagnosticados de TA en los últimos 20 años en nuestro centro. Resultados: Presentamos un total de 9 casos de angiomas en penacho en la infancia. El 77,7%…