Maria Koutsogiannaki

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State of the art objective measures for quantifying voice quality mostly consider estimation of features extracted from the magnitude spectrum. Assuming that speech is obtained by exciting a minimum-phase (vocal tract filter) and a maximum-phase component (glottal source), the amplitude spectrum cannot capture the maximum phase characteristics. Since voice(More)
TDMA has increasingly been used as the MAC layerfor ad-hoc networks. However, the use ofTDMA in multi-hop networks leads to the problem of distributing the available slots among the wireless nodes in an effective manner. The exact way the slots are distributed among the transmitting nodes has an impact on various performance parameters of the network, such(More)
Vocal tremor is defined as slow modulation of fundamental frequency or its amplitude [1, 2]. Even though vocal tremor may be attributed to neurological diseases, it may also be a natural stochastic modulation of voice. Many studies try to measure these modulations assuming that they are stationary. Hence, their analysis is limited to small intervals loosing(More)
—Despite its dominance as a MAC layer for ad-hoc communications, the CSMA/CA algorithm produces several deficiencies, like complex QoS capabilities, increased overhead, and the exposed terminal problem. The TDMA MAC layer, that mostly overcomes these issues, needs efficient scheduling in order to be employed in ad-hoc networks. At the same time, the current(More)
Clear speech is a speaking style adopted by speakers in an attempt to maximize the clarity of their speech and is proven to be more intelligible than casual speech. This work focuses on modifying casual speech to sound as intelligible as clear speech. First, we examine the role of speaking rate for intelligibility. Clear and casual speech signals are(More)
In this work we present "AlertMe", a semantics-based, context-aware notification system that provides personalized alerts to graduate students based on their preferences. An extensive description of the system is carried out. We present the underlying ontology that models the available knowledge, as well as how higher level knowledge inference and(More)
the objective of this work is the estimation of vocal tremor in patients with spasmodic dysphonia before and after treatment, and the comparison of their tremor characteristics with those estimated from healthy speakers. as an outcome, a new tremor attribute is introduced, the deviation of the modulation level and a novel method is proposed for classifying(More)
Among the key acoustic features attributed with the intelligibility gain of Clear speech are the observed reduction in speaking rate and expansion of vowel space, representing greater articulation and vowel discrimination. Considering the slower speaking rate, previous works have attempted to assess the intelligibility impact of time-scaling casual speech(More)
In this paper, the problem of modifying casual speech to reach the intelligibility level of clear speech is addressed. Unlike other studies, in this work modifications on casual speech both consider intelligibility and speech quality. To achieve this, the authors focus on human-like modifications inspired by clear speech. An acoustic analysis performed on(More)