Search results for "Systems architecture"
showing 10 items of 227 documents
Toward Unified Control of Networks of Switches and Sensors Through a Network Operating System
2018
Wireless sensor networks (WSNs) are an integral part of an Internet of Things (IoT) ecosystem. In fact, a typical IoT service deployment considers an integrated network of switches and sensors (as well as actuators). In order to manage this heterogeneous network infrastructure, the use of software defined networking (SDN) technologies is anticipated. However, existing SDN-enabling technologies consider only isolated networks and there has been no concrete solution that treats the whole network in a unified way. In this paper, a network operating system is proposed as a way to address the above issue. Starting from the open network operating system, which currently supports only OpenFlow net…
A secure architecture for P2PSIP-based communication systems
2009
Today, Peer-to-Peer SIP based communication systems have attracted much attention from both academia and industry. The decentralized nature of P2P might provide the distributed peer-to-peer communication system without help of the traditional SIP server. However, it comes to the cost of reduced manageability and therefore causes security problems, e.g. distrust, privacy leaks, unpredictable availability, etc. In this paper, we investigate on P2PSIP security issues and propose a proxy-based system architecture that improves security during P2PSIP session initiation. The main issues considered in this architecture include Source inter-working, Encryption & Decryption, Policy Management, Desti…
Teacher professional development in the context of the “Open Discovery of STEM laboratories” project: Is the MOOC methodology suitable for teaching p…
2020
Abstract The “Open Discovery of STEM Laboratories” (ODL) project, funded by the European Erasmus+ KA2 program, was aimed at introducing the use of MOOCs in school curricula. In particular, it fostered teacher collaboration in creating and using micro-MOOCs for the inclusion of STEM (Science, Technology, Engineering and Mathematics) online remote or virtual laboratories in the everyday teaching practice. The project focused on teachers, educators and curriculum designers with the aim to strengthen their profile by supporting them to deliver high quality teaching practices and to adopt new methods and tools. Thanks to the project, in service and pre-service teachers had the opportunity to ext…
The ATLAS level-1 trigger: Status of the system and experience from commissioning with cosmic ray muons
2007
The detector at CERN's large hadron collider (LHC) was exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting events in order to reduce this rate to 100- 200 Hz. A trigger decision is made by the Level-1 central trigger processor (CTP) reducing the incoming rate to less than 100 kHz. The Level-1 decision is based on calorimeter information and hits in dedicated muon trigger detectors. The final Level-1 trigger system is currently being installed in the experiment with completion expected in autumn 2007. Cosmic ray data are regularly recorded as an increasing fraction of the trigger system comes online. We present a…
A Low-level Simulation Study of Prioritization in IEEE 802.11e Contention-based Networks
2006
This work deals with the performance evaluation of the IEEE 802.11e EDCA proposal for service prioritization in Wireless LANs. A large amount of study has been carried out in the scientific community to evaluate the performance of the EDCA proposal, mainly in terms of throughput and access delay differentiation. However, we argue that further performance insights are needed in order to fully understand the principles behind the EDCA prioritization mechanisms. To this purpose, rather than limit our investigation on throughput and delay performance figures, we take a closer look to their operation also in terms of low-level performance metrics (such as probability of accessing specific channe…
Experiencia de reflexión con un profesor de biología chileno acerca de su práctica de enseñanza
2020
Las prácticas de enseñanza, por su naturaleza contextual y forma particular de implementarse, pueden favorecer o limitar los aprendizajes en el contexto escolar. En esa perspectiva, se diseña un estudio de caso que indaga en el contenido de la reflexión acerca de la práctica de enseñanza de un profesor de biología en servicio. Para ello, el profesor realiza una observación crítica de su práctica, comentando todas aquellas situaciones de enseñanza que le resultan preocupantes. Cada observación comentada fue profundizada a través de una entrevista focalizada. La información de las observaciones comentadas y entrevistas focalizadas fue analizada con el software Atlas-ti 8.0. De ahí emergieron …
An adaptive approach to learning the preferences of users in a social network using weak estimators
2012
Published version of an article in the journal: Journal of Information Processing Systems. Also available from the publisher at: http://dx.doi.org/10.3745/JIPS.2012.8.2.191 - Open Access Since a social network by definition is so diverse, the problem of estimating the preferences of its users is becoming increasingly essential for personalized applications, which range from service recommender systems to the targeted advertising of services. However, unlike traditional estimation problems where the underlying target distribution is stationary; estimating a user's interests typically involves non-stationary distributions. The consequent time varying nature of the distribution to be tracked i…
A Proposed Knowledge Based Approach for Solving Proteomics Issues
2010
In this paper we present a novel knowledge-based approach that aims at helping scientists to face and resolve a large number of proteomics problem. The system architecture is based on an ontology to model the knowledge base, a reasoner that starting from the user's request and a set of rules builds the workflow of tasks to be done, and an executor that runs the algorithms and software scheduled by the reasoner. The system can interact with the user showing him intermediate results and several options in order to refine the workflow and supporting him to choose among different forks. Thanks to the presence of the knowledge base and the modularity provided by the ontology, the system can be e…
Time and work generalised precedence relationships in project scheduling with pre-emption: An application to the management of Service Centres
2012
Abstract In this paper we present an application of project scheduling concepts and solution procedures for the solution of a complex problem that comes up in the daily management of many company Service Centres. The real problem has been modelled as a multi-mode resource-constrained project scheduling problem with pre-emption, time and work generalised precedence relationships with minimal and maximal time lags between the tasks and due dates. We present a complete study of work GPRs which includes proper definitions, a new notation and all possible conversions amongst them. Computational results that show the efficiency of the proposed hybrid genetic algorithm and the advantages of allowi…
Orchesting Inclusive Evaluation in Schools. Where We Could Start?
2019
Es cierto que en los últimos años se ha avanzado bastante en un discurso de la inclusividad potente y fundamentado, pero las prácticas siguen la inercia de una evaluación que parte de que todos los estudiantes son iguales. Se sigue arrastrando una cultura evaluativa asentada en que el aprendizaje está al servicio de la evaluación y la enseñanza termina subordinada a esta última. Una cultura reduccionista y calificadora muy arraigada, resistente al cambio y que cuesta mucho de reconstruir y transformar hacia una evaluación para la inclusión. En teoría hemos pasado de una evaluación centrada en la comprobación del saber, la certificación, el control, la calificación, etc. y en la que todos lo…