Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Publicações

Publicações por CTM

2016

Strengthening Marine and Maritime Research and Technology The STRONGMAR project

Autores
Silva, E; Martins, A; Dias, A; Matos, A; Olivier, A; Pinho, C; de Sa, FA; Ferreira, H; Silva, H; Alves, JC; Almeida, JM; Pessoa, L; Ricardo, M; Cruz, N; Dias, N; Monica, P; Jorge, P; Campos, R;

Publicação
OCEANS 2016 MTS/IEEE MONTEREY

Abstract
INESC TEC is strongly committed to become a center of excellence in maritime technology and, in particular, deep sea technology. The STRONGMAR project aims at creating solid and productive links in the global field of marine science and technology between INESC TEC and established leading research European institutions, capable of enhancing the scientific and technological capacity of INESC TEC and linked institutions, helping raising its staff's research profile and its recognition as a European maritime research center of excellence. The STRONGMAR project seeks complementarity to the TEC4SEA research infrastructure: on the one hand, TEC4SEA promotes the establishment of a unique infrastructure of research and technological development, and on the other, the STRONGMAR project intends to develop the scientific expertise of the research team of INESC TEC.

2016

The self-configuration of nodes using RSSI in a dense wireless sensor network

Autores
Abdellatif, MM; Oliveira, JM; Ricardo, M;

Publicação
TELECOMMUNICATION SYSTEMS

Abstract
Wireless sensor networks (WSNs) may be made of a large amount of small devices that are able to sense changes in the environment, and communicate these changes throughout the network. An example of a similar network is a photo voltaic (PV) power plant, where there is a sensor connected to each solar panel. The task of each sensor is to sense the output of the panel which is then sent to a central node for processing. As the network grows, it becomes impractical and even impossible to configure all these nodes manually. And so, the use of self-organization and auto-configuration algorithms becomes essential. In this paper, three algorithms are proposed that allow nodes in the network to automatically identify their closest neighbors, relative location in the network, and select which frequency channel to operate in. This is done using the value of the Received Signal Strength Indicator (RSSI) of the messages sent and received during the setup phase. The performance of these algorithms is tested by means of both simulations and testbed experiments. Results show that the error in the performance of the algorithms decreases as we increase the number of RSSI values used for decision making. Additionally, the number of nodes in the network affects the setup error. However, the value of the error is still acceptable even with a high number of nodes.

2016

Improving ns-3 Emulation Performance for Fast Prototyping of Network Protocols

Autores
Fontes, H; Cardoso, T; Ricardo, M;

Publicação
Proceedings of the Workshop on ns-3, WNS3 '16, Seattle, WA, USA, June 15-16, 2016

Abstract
A common problem in networking research and development is the duplicate effort of writing simulation and implementation code of network protocols. This duplication can be avoided through the use of fast prototyping development processes, which enable reusing simulation code in real prototyping and in production environments. Although this functionality is already available by using ns-3 emulation, there are still limitations regarding the additional packet processing that emulation introduces, which degrades the node’s performance and limits the amount of network traffic that can be processed. In this paper we propose an approach to reduce the performance problem associated with fast prototyping that consists in migrating data plane operations processing to outside of ns-3. In a well-designed network, most of the traffic should be data. By moving the data plane operations outside of ns-3 the overhead associated with this kind of traffic is greatly reduced, while control plane protocols may still be reused. In order to validate our proposed solution, we extended the Wireless Metropolitan Routing Protocol (WMRP) and Optimized Link State Routing (OLSR) protocols to use the developed architecture, tested their performance in real environments, and verified the amount of code reuse between the simulator and the real system. © 2016 ACM.

2016

A hybrid recommendation system for news in a mobile environment

Autores
Viana, P; Soares, M;

Publicação
ACM International Conference Proceeding Series

Abstract
Over the last few years consumption of news articles has shifted more and more from the written versions towards the web. Mobile devices, which became more powerful, with larger screens and connected to the Internet, have had a great influence on this paradigm change. A critical problem associated to online news is related to the fact that the large number of daily articles can be overwhelming to the users. Recommendation services can largely improve the efficiency and accuracy of acquired information. These systems are designed to filter critical news, key events and meaningful items that might be of interest to a reader. In this paper, a news recommendation system in a mobility scenario is presented. The implemented recommendation system combines content-based and georeferenced recommendation techniques. Recommendations are supported by short-term and long-term user profiles created implicitly and considering also the mobile device geolocation. The final recommendation list is obtained by combining recommendations provided by the different recommendation approaches. To evaluate the performance of the solution, a user study was conducted. Results indicate that the quality of the recommendations is acknowledged by the test users. The system was integrated in a mobile application of a Portuguese newspaper (Público) in the context of the project Pglobal. © 2016 ACM.

2016

Guest Editorial: Immersive Media Experiences

Autores
Viana, P; Chambel, T; Bove, VM; Strover, S; Thomas, G;

Publicação
MULTIMEDIA TOOLS AND APPLICATIONS

Abstract
Multimedia content has the potential for significant impact on users’ emotions, their sense of presence and engagement experiencing the service, application or information being provided, in immersive environments. The evolution of technology, user expectations and results from research activities have led to an enormous increase in the amount of content delivered in different formats, via a number of heterogeneous communication networks, to a range of devices, many of them portable and offering tremendous opportunities for immersion, user participation and personalization. New paradigms for media production, distribution and consumption have been emerging, introducing different sensory modalities and audio-visual surround effects, for an increased sense of presence, and also enabling participation and social interaction in the media chain, thus increasing the sense of belonging and contributing to the success of the services being provided

2016

Statistically Enhanced Analogue and Mixed-Signal Design and Test

Autores
Ramos, PL; da Silva, JM; Ferreira, DR; Santos, MB;

Publicação
PROCEEDINGS OF THE 2016 IEEE 21ST INTERNATIONAL MIXED-SIGNALS TEST WORKSHOP (IMSTW)

Abstract
The design, manufacture and operational characteristics (e.g., yield, performance, and reliability) of modern electronic integrated systems exhibit extreme levels of complexity that cannot be easily modelled or predicted. Different mathematical methodologies have been explored to address this issue. Monte Carlo simulation is the most widely employed and straightforward approach to evaluate the circuits' performance statistics. However, the high number of trial cases and the long simulations times required to obtain results for complex circuits with a ppm resolution, lead to very long analysis times. The present work addresses the evaluation of alternative statistical inference methodologies which allow obtaining similar results departing from a smaller dimension data set of Monte Carlo simulations from which the overall population is estimated. These methodologies include the use of Bayesian inference, Expectation-inimization, and Kolmogorov-Smirnov tests. Results are presented which show the validity of these approaches.

  • 155
  • 324