Papers by CTM researchers published in international journals

Papers by CTM researchers published in international journals

Researchers from INESC TEC’s Centre for Telecommunications and Multimedia (CTM) have published six more papers in international journals.

29th April 2015

The first paper, titled “Assessing Cosmetic Results After Breast Conserving Surgery”, not only reviews research on aesthetic evaluation of breast cancer conservative treatment, but also outlines future developments to create a user-friendly tool, accepted by the scientific community, to compare results and improve surgical techniques used.

With this paper, CTM researchers Hélder Oliveira, Jaime Cardoso and Maria João Cardoso wanted to respond to several questions on this topics, such as: the factors which have an impact on breast cancer conservative treatment, the parameters or characteristics that should be considered in aesthetic evaluations, the way patients are assessed and the scales used in this assessment, as well as the methods and technological solutions available to assess subjective and objective aesthetic results. The paper was published in the Journal of Surgical Oncology.

The paper “Real-time communication in IEEE 802.11s mesh networks: simulation assessment considering the interference of non-real-time traffic sources” describes a performance evaluation of IEEE 802.11s wireless mesh networks  to support real-time traffic when the physical space is shared with uncontrolled traffic. Using simulations, the researchers defined a set of real-time traffic flows, analysing different scenarios with different levels of interference. It was possible to verify that the real-time traffic is affected by the presence of strong sources of uncontrolled traffic in the network since the mechanism used to control access is not enough when prioritising traffic with time requirements.

Complementarily to the performance evaluation, the researchers conducted a thorough study in which they present suggestions of parameters to configure the network, in order to optimise the performance of the communication, and reduce the impact of interference on real-time traffic. This study is important to design new access control mechanisms that support communications with time requirements in IEEE 802.11s wireless mesh networks. The paper, published in the EURASIP Journal on Wireless Communications And Networking, was written by Paulo Portugal (CTM), Carlos (IdMEC-FEUP), Francisco Vasques (IdMEC-FEUP) and Ricardo Moraes (UFSC-Araranguá, Brazil).

In the paper “A New MSE Channel Estimator Optimized for Nonlinearly Distorted Faded OFDM Signals with Applications to Radio-over-Fiber”, researchers João Oliveira, Henrique Salgado and Miguel Rodrigues propose a new structure to estimate the channel that tries to minimise the mean squared error  of signals based on Orthogonal Frequency Division Multiplexing, corrupted by fading, non-linear distortion, and white Gaussian noise.

The researchers demonstrated that the estimator consists of a set of correlators adapted to each non-linear distorted signal frequency component, followed by a linear transformation. As a case study, the researchers analysed the case of up-link in a radio-over-fibre (ROF) system carrying WiFi signals. The results indicate that the performance of the estimator  is close to that of the ideal estimator, making it easier to relax  the nonlinear requirements of the ROF system, avoiding the use of pre-distortion techniques. This way, it is possible to reduce the complexity of the wireless radio system. This paper was published in the IEEE Transactions on Communications - IEEE Transactions on Communications.

Another paper is the "Context-aware media recommendations for smart devices," written by Abayomi Otebolaku and Maria Teresa Andrade from CTM. This work consisted of developing a platform for Android users that collects data from the sensors in the smartphone. Using machine learning and external interfaces, such as Google Maps or Yahoo Weather API, the platform makes it possible to understand the context the user is in and the surrounding environment, and thus recommend multimedia contents adapted to the situation of each user.

Simultaneously, the platform analyses the user’s consumption of multimedia contents in each of the situations detected, building a contextualised profile. This work, published in the Journal of Ambient Intelligence and Humanized Computing, can be applied in mobile tourism, assisted living, activity monitoring, among others.

"Semantically connected web resources with MPEG-21" is the title of the paper written by Hélder Fernandes Castro and Maria Teresa Andrade (CTM), Fernando Almeida (ex-CTM), G. Tropea, N. Blefari Melazzi (Univ of Rome Tor Vergata) A. S. Mouzas e D. I. Klaklamani (School of Electrical and Computer Engineering, Athens, Greecea), and L. Chiariglione and A. Difino (CEDEO). As part of this work, the researchers defined a data model according to existing standards and an ontology that can be extended in order to formalise the description of the semantic relationships between resources available on the Internet.

With this mechanism, it is possible to express, in an explicit way, the semantic relations between digital resources. That way, when we are consuming a certain content on the Web, we can access resources related to that content in a transparent way, even if there is no prior knowledge of the existence of that content, and without users having to explicitly look for them.  This mechanism can be used in any platform that provides digital contents or resources (e-learning, entertainment, e-commerce, etc.), having been incorporated in the MPEG-21da ISO/IEC international standard. The paper was published in the Springer Journal of Multimedia Tools and Applications.

Finally, in the paper “Experimental evaluation of a digitized fiber-wireless system employing sigma delta modulation”, a team of CTM researchers, composed of Luís Pessoa, Joana Tavares, Diogo Coelho and Henrique Salgado, proposed a new solution for the future implementation of radio-over-fibre systems. Using a sigma-delta pass-band modulator that works and a 1-bit analogic-to-digital converter on the transmitter side, the digital-to-analogic converters at the base stations can be suppressed, thus reducing their complexity and energy consumption. This paper was published in Optics Express.

CTM/INESC TEC, April 2015