Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by CTM

2013

The REFLECT design-flow

Authors
Cardoso, JMP; De F. Coutinho, JG; Nane, R; Sima, VM; Olivier, B; Carvalho, T; Nobre, R; Diniz, PC; Petrov, Z; Bertels, K; Gonçalves, F; Van Someren, H; Hübner, M; Constantinides, G; Luk, W; Becker, J; Krátký, K; Bhattacharya, S; Alves, JC; Ferreira, JC;

Publication
Compilation and Synthesis for Embedded Reconfigurable Systems: An Aspect-Oriented Approach

Abstract
This chapter describes the design-flow approach developed in the REFLECT project as presented originally in [1]. Over the course of the project, this design-flow has evolved and has been extended into a fully operational toolchain. We begin by presenting an overview of the underlying aspect-oriented compilation flow followed by an extended description of the design-flow and its toolchain. © Springer Science+Business Media New York 2013. All rights are reserved.

2013

Special issue of Microelectronics Journal on the Conference on Design of Circuits and Integrated Systems 2011 (DCIS 2011)

Authors
da Silva, JM; Renaud, S; Ferreira, JC;

Publication
MICROELECTRONICS JOURNAL

Abstract

2013

A HYBRID LF-ROSENBERG FREQUENCY-DOMAIN MODEL OF THE GLOTTAL PULSE

Authors
Dias, S; Ferreira, A;

Publication
2013 IEEE WORKSHOP ON APPLICATIONS OF SIGNAL PROCESSING TO AUDIO AND ACOUSTICS (WASPAA)

Abstract
In this paper we describe innovative advances to the design of a new frequency-domain algorithm to glottal source estimation whose conceptual approach we have reported recently [1]. Those advances result from accurate sinusoidal/harmonic analysis and synthesis of two concomitant acoustic signals: the glottal source signal captured near the vocal folds, and the corresponding voiced signal captured outside the mouth. We describe the experimental procedure which was performed by an ORL specialist using a rigid video-laryngoscope and two tiny and high-quality microphones. Six subjects have participated in the tests and records were made for vowels /a/ and /i/. The data analysis allowed us to conclude on the magnitude and on the phase-related NRD features of the glottal source signal. In addition, a new frequency-domain glottal pulse model combining features of the Liljencrants-Fant and Rosenberg models has been devised that is a better match to the observed data. The derivatives of the three models are obtained using accurate frequency-domain processing. The paper concludes with next research steps.

2013

End-to-End Delay Estimation using RPL Metrics in WSN

Authors
Pinto, P; Pinto, A; Ricardo, M;

Publication
2013 IFIP WIRELESS DAYS (WD)

Abstract
Critical monitoring applications can use wireless sensor networks to transport delay sensitive data. This data may demand bounded delays in order to be considered useful by the receiver. In these cases, an accurate and real-time estimation of the end-to-end delay could be used to anticipate the data usefulness prior to sending it. A novel real-time and end-to-end delay estimation mechanism is proposed in this paper, which considers processing times and two new RPL metrics. Results show that our proposal is more accurate than the ETT-based solution for delay estimation, and it does not significantly degrade the network performance.

2013

The Effect of Data Aggregation on the Performance of a Wireless Sensor Network Employing a Polling Based Data Collecting Technique

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

Publication
2013 IFIP WIRELESS DAYS (WD)

Abstract
Wireless Sensor Networks (WSNs) consist of small devices capable of sensing various variables in the environment, process and communicate them through the network. These devices interact together to carry out monitoring tasks. A photo-voltaic (PV) power plant is an example of such network, where each solar panel has a sensor connected to it. The number of interconnected solar panels can become very large in order to cover a large area. Each sensor senses the output of the panel and sends this value to a central node for processing. In this paper we study and compare the performance of a multi-hop wireless sensor network, employing a polling based data collecting technique with data aggregation, against the performance of a one hop network employing two different data collecting techniques. The study considers a wireless network with fixed number of nodes using different values of the offered load, estimating the network throughput for each technique and offered load. The use of a multi-hop setup was chosen in order to reduce transmission power and interference among nodes. Results show that the multi-hop network, using the polling based data collecting technique with data aggregation, performs close to the one hop network using the other two techniques. The study involves both simulation and testbed experimentation.

2013

Context-aware low-energy Wi-Fi sensor networks for e-health

Authors
Carvalho, L; Campos, R; Ricardo, M;

Publication
IEEE 15th International Conference on e-Health Networking, Applications and Services, Healthcom 2013, Lisbon, Portugal, October 9-12, 2013

Abstract
Typical sensor networks are formed by low-end, battery operated devices, which rely on low-energy communication technologies, such as Bluetooth, Zigbee and ANT+, due to their energy efficiency. On the other hand, sensor networks increasingly need to be connected to the Internet, which implies adaptations of the TCP/IP stack to fit such wireless technologies. These adaptations bring additional complexity and imply new hardware, thus deployments are cumbersome and sub-optimal. Conversely, Wi-Fi is ubiquitous, can be seamlessly integrated with TCP/IP, and is energy-efficient with the right configurations; yet, its usage is still uncommon in e-health scenarios. For these reasons, we argue that a TCP/IP over Wi-Fi approach should be followed in e-health sensor networks. We propose a novel cross-layer, context-aware network configuration mechanism, which monitors the user and networking contexts and optimizes the configuration of the TCP/IP protocol stack accordingly. Our approach enables seamless integration between e-health wireless sensor networks and the TCP/IP backbone, while improving energy efficiency and reliability. © 2013 IEEE.

  • 263
  • 369