INESC-ID

About: INESC-ID is a nonprofit organization based out in Lisbon, Portugal. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 932 authors who have published 2618 publications receiving 37658 citations.

Leveraging Qualitative Reasoning to Improve SFL

Abstract: Spectrum-based fault localization (SFL) correlates a system's components with observed failures. By reasoning about coverage, SFL allows for a lightweight way of pinpointing faults. This abstraction comes at the cost of missing certain faults, such as errors of omission, and failing to provide enough contextual information to explain why components are considered suspicious. We propose an approach, named Q-SFL, that leverages qualitative reasoning to augment the information made available to SFL techniques. It qualitatively partitions system components, and treats each qualitative state as a new SFL component to be used when diagnosing. Our empirical evaluation shows that augmenting SFL with qualitative components can improve diagnostic accuracy in 54% of the considered real-world subjects.

Correlating ASR Errors with Developmental Changes in Speech Production: A Study of 3-10-Year-Old European Portuguese Children's Speech

Abstract: Automatically recognising children's speech is a very difficult task. This difficulty can be attributed to the high variability in children's speech, both within and across speakers. The variability is due to developmental changes in children's anatomy, speech production skills et cetera, and manifests itself, for example, in fundamental and formant frequencies, the frequency of disfluencies, and pronunciation quality. In this paper, we report the results of acoustic and auditory analyses of 3-10-year-old European Portuguese children's speech. Furthermore, we are able to correlate some of the pronunciation error patterns revealed by our analyses - such as the truncation of consonant clusters - with the errors made by a children's speech recogniser trained on speech collected from the same age group. Other pronunciation error patterns seem to have little or no impact on speech recognition performance. In future work, we will attempt to use our findings to improve the performance of our recogniser.

Combining local and remote laboratories for the interactive learning of industrial automation

Abstract: This study presents an educational project for the interactive learning of Industrial Automation. The objective of this project is to allow Bachelor's and Master's students of Electrical Engineering of the Instituto Superior de Engenharia de Lisboa (ISEL‐IPL) to learn theoretical and practical fundamentals of Industrial Automation through local and remote laboratory experiments. The proposed pedagogical activities, together with the flexibility of the solution adopted for the laboratory experiments, allow students to acquire advanced knowledge regarding Programmable Logic Controller (PLC) programming languages, Supervisory Control and Data Acquisition (SCADA) applications and industrial communication networks, among other aspects. The main benefits of this educational project are the motivation to engage in problem solving, developing mental strategies based on new hypotheses, step‐by‐step knowledge construction, and the possibility to interact and change, locally or remotely, the developed programs. Additionally, the adopted laboratory architecture is based on industrial hardware and software, like those found in real applications.

Experimental Evaluation of Phase-Noise and Quadrature Error in a CMOS 2.4 GHz Relaxation Oscillator

Abstract: Contrary to what happens with LC oscillators, the increase of coupling in cross-coupled relaxation RC-oscillators leads to a lower quadrature error and lower phase-noise. We present a 2.4 GHz CMOS quadrature relaxation oscillator, and show the measurements confirming this property. Increasing the coupling block gain, the oscillator phase-noise is reduced from -97 dBc/Hz to -104 dBc/Hz @ 1 MHz. The quadrature error is reduced from 4.3deg to 0.8deg. These results show that RC quadrature oscillators may be a practical alternative for RF transceiver applications.

Sequential pattern mining with approximated constraints

Abstract: The lack of focus that is a characteristic of unsupervised pattern mining in sequential data represents one of the major limitations of this approach. This lack of focus is due to the inherently large number of rules that is likely to be discovered in any but the more trivial sets of sequences. Several authors have promoted the use of constraints to reduce that number, but those constraints approximate the mining task to a hypothesis test task. In this paper, we propose the use of constraint approximations to guide the mining process, reducing the number of discovered patterns without compromising the prime goal of data mining: to discover unknown information. We show that existent algorithms, that use regular languages as constraints, can be used with minor adaptations. We propose a simple algorithm (e-accepts) that verifies if a sequence is approximately accepted by a given regular language.