Exploring Superframe Co-occurrence for Acoustic Event Recognition

We introduce in this paper a concept of using acoustic superframes, a mid-level representation which can overcome the drawbacks of both global and simple frame-level representations for acoustic events. Through superframe-level recognition, we explore the phenomenon of superframe co-occurrence across different event categories and propose an efficient classification scheme that takes advantage of this feature sharing to improve the event-wise recognition power. We empirically show that our recognition system results in 2.7% classification error rate on the ITC-Irst database. This state-of-the-art performance demonstrates the efficiency of this proposed approach. Furthermore, we argue that this presentation can pretty much facilitate the event detection task compared to its counterparts, e.g. global and simple frame-level representations

A Multi-Channel Fusion Framework for Audio Event Detection

We propose in this paper a simple, yet efficient multi-channel fusion framework for joint acoustic event detection and classification. The joint problem on individual channels is posed as a regression problem to estimate event onset and offset positions. As an intermediate result, we also obtain the posterior probabilities which measure the confidence that event onsets and offsets are present at a temporal position. It facilitates the fusion problem by accumulating the posterior probabilities of different channels. The detection hypotheses are then determined based on the summed posterior probabilities. While the proposed fusion framework appears to be simple and natural, it significantly outperforms all the single-channel baseline systems on the ITC-Irst database. We also show that adding channels one by one into the fusion system yields performance improvements, and the performance of the fusion system is always better than those of the individual-channel counterparts

Audio Phrases for Audio Event Recognition

The bag-of-audio-words approach has been widely used for audio event recognition. In these models, a local feature of an audio signal is matched to a code word according to a learned codebook. The signal is then represented by frequencies of the matched code words on the whole signal. We present in this paper an improved model based on the idea of audio phrases which are sequences of multiple audio words. By using audio phrases, we are able to capture the relationship between the isolated audio words and produce more semantic descriptors. Furthermore, we also propose an efficient approach to learn a compact codebook in a discriminative manner to deal with high-dimensionality of bag-of-audio-phrases representations. Experiments on the Freiburg-106 dataset show that the recognition performance with our proposed bag-of-audio-phrases descriptor outperforms not only the baselines but also the state-of-the-art results on the dataset

Representing Nonspeech Audio Signals through Speech Classification Models

The human auditory system is very well matched to both human speech and environmental sounds. Therefore, the question arises whether human speech material may provide useful information for training systems for analyzing nonspeech audio signals, such as in a recognition task. To find out how similar nonspeech signals are to speech, we measure the closeness between target nonspeech signals and different basis speech categories via a speech classification model. The speech similarities are finally employed as a descriptor to represent the target signal. We further show that a better descriptor can be obtained by learning to organize the speech categories hierarchically with a tree structure. We conduct experiments for the audio event analysis application by using speech words from the TIMIT dataset to learn the descriptors for the audio events of the Freiburg-106 dataset. Our results on the event recognition task outperform those achieved by the best system even though a simple linear classifier is used. Furthermore, integrating the learned descriptors as an additional source leads to improved performance

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

Learning Representations for Nonspeech Audio Events through Their Similarities to Speech Patterns

The human auditory system is very well matched to both human speech and environmental sounds. Therefore, the question arises whether human speech material may provide useful information for training systems for analyzing nonspeech audio signals, for example, in a classification task. In order to answer this question, we consider speech patterns as basic acoustic concepts which embody and represent the target nonspeech signal. To find out how similar the nonspeech signal is to speech, we classify it with a classifier trained on the speech patterns and use the classification posteriors to represent the closeness to the speech bases. The speech similarities are finally employed as a descriptor to represent the target signal. We further show that a better descriptor can be obtained by learning to organize the speech categories hierarchically with a tree structure. Furthermore, these descriptors are generic. That is, once the speech classifier has been learned, it can be employed as a feature extractor for different datasets without re-training. Lastly, we propose an algorithm to select a sufficient subset which provides an approximate representation capability of the entire set of available speech patterns. We conduct experiments for the application of audio event analysis. Phone triplets from the TIMIT dataset were used as speech patterns to learn the descriptors for audio events of three different datasets with different complexity, including UPC-TALP, Freiburg-106, and NAR. The experimental results on the event classification task show that a good performance can be easily obtained even if a simple linear classifier is used. Furthermore, fusion of the learned descriptors as an additional source leads to state-of-the-art performance on all the three target datasets

Telecommunication Systems

This book is based on both industrial and academic research efforts in which a number of recent advancements and rare insights into telecommunication systems are well presented. The volume is organized into four parts: "Telecommunication Protocol, Optimization, and Security Frameworks", "Next-Generation Optical Access Technologies", "Convergence of Wireless-Optical Networks" and "Advanced Relay and Antenna Systems for Smart Networks." Chapters within these parts are self-contained and cross-referenced to facilitate further study

SPARC 2018 Internationalisation and collaboration : Salford postgraduate annual research conference book of abstracts

Welcome to the Book of Abstracts for the 2018 SPARC conference. This year we not only celebrate the work of our PGRs but also the launch of our Doctoral School, which makes this year’s conference extra special. Once again we have received a tremendous contribution from our postgraduate research community; with over 100 presenters, the conference truly showcases a vibrant PGR community at Salford. These abstracts provide a taster of the research strengths of their works, and provide delegates with a reference point for networking and initiating critical debate. With such wide-ranging topics being showcased, we encourage you to take up this great opportunity to engage with researchers working in different subject areas from your own. To meet global challenges, high impact research inevitably requires interdisciplinary collaboration. This is recognised by all major research funders. Therefore engaging with the work of others and forging collaborations across subject areas is an essential skill for the next generation of researchers