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Publications

Publications by Manuel Ricardo

2011

On performance of group key distribution techniques when applied to IPTV services

Authors
Pinto, A; Ricardo, M;

Publication
COMPUTER COMMUNICATIONS

Abstract
IPTV services consist of multiple video channels grouped in bundles, such as sports, movies or generic bundles; users typically subscribe multiple bundles, including the generic bundle. Secure IP multicast can be used to implement IPTV services, but it still has problems to be addressed. Current solutions require high computational power in video channel zapping situations, lack support for groups sourced at the users, and present a weak support for admission control in IP multicast for both sources and receivers in dynamically configured environments. This work proposes a new, secure and efficient IPTV solution that, cumulatively: (a) enforces individual access control to groups of real-time IPTV video channels; (b) enforces IP multicast admission control for both multicast senders and receivers; (c) supports user generated videos; (d) generates low signaling overheads; (e) does not introduce perceivable delays, particularly in video channel zapping situations. Moreover, this solution can be easily integrated in the IPTV architectures being developed by ETSI and ITU-T.

2005

Dynamic autoconfiguration in 4G networks: problem statement and preliminary solution

Authors
Campos, R; Ricardo, M;

Publication
Proceedings of the 1st ACM workshop on Dynamic interconnection of networks, DIN@MobiCom 2005, Cologne, Germany, September 2, 2005

Abstract
The Internet is characterized by the coexistence of two Internet Protocol (IP) versions and multiple autoconfiguration mechanisms which are deployed targeting specific communication scenarios. This heterogeneity requires user pre-configurations, namely with respect to the proper autoconfiguration mechanism to be used at each time. On the other hand, future networks may imply that users own personal networks demanding self-configuration and self-management, and being part of very dynamic scenarios. In this paper we make a survey of the autoconfiguration mechanisms available for IP networks, and argue that a new solution is needed, so that the proper autoconfiguration mechanism can be selected automatically, dynamically and efficiently, and future communication paradigms can be properly addressed. Copyright 2005 ACM.

1993

TGDS - A NEW TOOL FOR PERFORMANCE EVALUATION OF HSLANS

Authors
ASSIS, P; ALMEIDA, A; HENRIQUES, M; RICARDO, M; FERREIRA, P; PROENCA, P; CARRAPATOSO, E;

Publication
LOCAL AND METROPOLITAN AREA NETWORKS

Abstract
The test and performance evaluation of high speed networks pose problems that cannot be solved by traditional equipment. In this paper, the concept of a powerful and versatile tool, capable of generating and detecting traffic to test and assess the performance of such networks, is presented.

2009

FlowMonitor: a network monitoring framework for the network simulator 3 (NS-3)

Authors
Carneiro, G; Fortuna, P; Ricardo, M;

Publication
4th International Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS '09, Pisa, Italy, October 20-22, 2009

Abstract

2012

Multi-technology RF fingerprinting with leaky-feeder in underground tunnels

Authors
Pereira, F; Theis, C; Moreira, A; Ricardo, M;

Publication
2012 INTERNATIONAL CONFERENCE ON INDOOR POSITIONING AND INDOOR NAVIGATION (IPIN)

Abstract
Techniques using RSS fingerprinting for localization have been studied over a number of different technologies in many different scenarios. In the case of underground tunnels localization can be quite challenging, yet it is extremely important for safety reasons. In the specific case of the CERN tunnels, accurate and automatized localization methods would additionally allow the workflow of some activities to become substantially faster. In a radiation area this would also have the added benefit of reducing the exposure time of personnel conducting so called radiation surveys which have to be carried out before access can be granted. In this paper Fingerprinting techniques for GSM and Wireless LAN are studied and enhanced to take advantage of both network technologies simultaneously as well as the channels RSS differential and an observed effect in the radiated power in the leaky-feeder cables. Besides the higher accuracy achieved for a single technology, this methodology looks promising for scenarios where several types of wireless networks are available or expected to be installed at a later stage.

2012

Impact of data collecting techniques on the performance of a Wireless Sensor Network

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

Publication
2012 International Symposium on Wireless Communication Systems (ISWCS), Paris, France, August 28-31, 2012

Abstract
Wireless Sensor Networks (WSNs) consist of small devices with processing, communication and sensing capabilities. These devices interact together to carryout monitoring tasks. An example of such network is a photo-voltaic (PV) power plant where each solar panel has a sensor. The number of interconnected solar panels can become very large, and spread over a large area. Each sensor will sense the output of the panel and send this value to a central node for processing. In this paper we evaluate the performance of a wireless sensor network employing three different data collecting techniques. The study considers different networks, each with a different number of nodes and with different values for the offered load, estimating for each network size and offered load, network throughput, packet loss and end-to-end packet delay. Results show that as the size of the network grows and for higher values of the offered load, the best performance is achieved by using a polling based data collecting technique. © 2012 IEEE.

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