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Publications

Publications by CTM

2017

On the relevance of F0, Jitter, Shimmer and HNR acoustic parameters in forensic voice comparisons using GSM, VOIP and contemporaneous high-quality voice recordings

Authors
Fernandes, V; Ferreira, A;

Publication
Proceedings of the AES International Conference

Abstract
GSM and VOIP telephonic voice recordings are frequently used in forensic voice comparisons. However, speech compression, enhancement and error correction algorithms are likely to modify speaker specific voice characteristics. We performed high-quality voice recordings and concomitant GSM and VOIP telephonic voice recordings so that clean high-quality and telephonic versions of the same speech are available. Sustained vowel tasks are also included allowing F0 (AVG and STD), Jitter, Shimmer and HNR extraction for pairs of contemporaneous recordings. Twenty female and seventeen male volunteer subjects participated in the study. We describe the voice recording experiments, present results for five vowels and five acoustic parameters for each subject in GSM and VOIP communication, and we discuss the implications of the main results.

2017

CARMIE

Authors
Lobo, J; Ferreira, L; Ferreira, AJ;

Publication
Health Care Delivery and Clinical Science

Abstract
The incidence of chronic diseases is increasing and monitoring patients in a home environment is recommended. Noncompliance with prescribed medication regimens is a concern, especially among older people. Heart failure is a chronic disease that requires patients to follow strict medication plans permanently. With the objective of helping these patients managing information about their medicines and increasing adherence, the personal medication advisor CARMIE was developed as a conversational agent capable of interacting, in Portuguese, with users through spoken natural language. The system architecture is based on a language parser, a dialog manager, and a language generator, integrated with already existing tools for speech recognition and synthesis. All modules work together and interact with the user through an Android application, supporting users to manage information about their prescribed medicines. The authors also present a preliminary usability study and further considerations on CARMIE.

2017

Mistrustful P2P: Deterministic privacy-preserving P2P file sharing model to hide user content interests in untrusted peer-to-peer networks

Authors
da Silva, PM; Dias, J; Ricardo, M;

Publication
COMPUTER NETWORKS

Abstract
P2P networks endowed individuals with the means to easily and efficiently distribute digital media over the Internet, but user legal liability issues may be raised as they also facilitate the unauthorized distribution and reproduction of copyrighted material. Traditional P2P file sharing systems focus on performance and scalability, disregarding any privacy or legal issues that may arise from their use. Lacking alternatives, and unaware of the privacy issues that arise from relaying traffic of insecure applications, users have adopted anonymity systems for P2P file sharing. This work aims at hiding user content interests from malicious peers through plausible deniability. The Mistrustful P2P model is built on the concept of mistrusting all the entities participating in the P2P network, hence its name. It provides a deterministic and configurable privacy protection that relies on cover content downloads to hide user content interests, has no trust requirements, and introduces several mechanisms to prevent user legal liability and reduce network overhead while enabling timely content downloads. We extend previous work on the Mistrustful P2P model by discussing its legal and ethical framework, assessing its feasibility for more use cases, providing a security analysis, comparing it against a traditional P2P file sharing model, and further defining and improving its main mechanisms.

2017

A Trace-based ns-3 Simulation Approach for Perpetuating Real-World Experiments

Authors
Fontes, H; Campos, R; Ricardo, M;

Publication
Proceedings of the Workshop on ns-3, Porto, Portugal, June 13 - 14, 2017

Abstract
A common problem in mobile networking research and development is the cost related to deploying and running real-world mobile testbeds. Due to cost and operational constraints, these testbeds usually run for short time periods but generate very unique and relevant results that are hard to reproduce. We propose the use of ns-3 as a solution to successfully reproduce real-world mobile testbed experiments. This is accomplished by feeding ns-3 with real testbed traces including node positions and radio link quality only. In order to validate our approach, the network throughput between a fixed Base Station and a Unmanned Aerial Vehicle (UAV) was measured in a real-world testbed. The experimental results were compared to the network throughput achieved using the ns-3 trace-based simulation and a plain ns-3 simulation. The obtained results show the high accuracy of the trace-based simulation, thus validating our approach. © 2017 ACM.

2017

2017 Wireless Days, Porto, Portugal, March 29-31, 2017

Authors
Ricardo, Manuel; Campos, Rui; Ruela, Jose; Morla, Ricardo; Teixeira, Filipe; Pessoa, Luis; Salgado, Henrique;

Publication
Wireless Days

Abstract

2017

Synchronization of application-driven WSN

Authors
Marques, B; Ricardo, M;

Publication
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING

Abstract
The growth of wireless sensor networks (WSN) has resulted in part from requirements for connecting sensors and advances in radio technologies. WSN nodes may be required to save energy and therefore wake up and sleep in a synchronized way. In this paper, we propose an application-driven WSN node synchronization mechanism which, by making use of cross-layer information such as application ID and duty cycle, and by using the exponentially weighted moving average (EWMA) technique, enables nodes to wake up and sleep without losing synchronization. The results obtained confirm that this mechanism maintains the nodes in a mesh network synchronized according to the applications they run, while maintaining a high packet reception ratio.

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