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  • Conference paper
    Yiallourides C, Moore AH, Auvinet E, Van der Straeten C, Naylor PAet al., 2018,

    Acoustic Analysis and Assessment of the Knee in Osteoarthritis During Walking

    , IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 281-285

    We examine the relation between the sounds emitted by the knee joint during walking and its condition, with particular focus on osteoarthritis, and investigate their potential for noninvasive detection of knee pathology. We present a comparative analysis of several features and evaluate their discriminant power for the task of normal-abnormal signal classification. We statistically evaluate the feature distributions using the two-sample Kolmogorov-Smirnov test and the Bhattacharyya distance. We propose the use of 11 statistics to describe the distributions and test with several classifiers. In our experiments with 249 normal and 297 abnormal acoustic signals from 40 knees, a Support Vector Machine with linear kernel gave the best results with an error rate of 13.9%.

  • Conference paper
    Li Z, Pei W, Xia Y, Wang K, Mandic DPet al., 2018,

    WIDELY LINEAR CLMS BASED CANCELATION OF NONLINEAR SELF-INTERFERENCE IN FULL-DUPLEX DIRECT-CONVERSION TRANSCEIVERS

    , IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 4329-4333
  • Conference paper
    Deng X, Huang J, Liu M, Dragotti PLet al., 2018,

    U-FRESH: AN FRI-BASED SINGLE IMAGE SUPER RESOLUTION ALGORITHM AND AN APPLICATION IN IMAGE COMPRESSION

    , IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 1807-1811
  • Conference paper
    Dees BS, Xia Y, Douglas SC, Mandic DPet al., 2018,

    CORRENTROPY-BASED ADAPTIVE FILTERING OF NONCIRCULAR COMPLEX DATA

    , IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 4339-4343
  • Conference paper
    Huang J-J, Dragotti PL, 2018,

    A DEEP DICTIONARY MODEL FOR IMAGE SUPER-RESOLUTION

    , IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 6777-6781
  • Journal article
    Evers C, Naylor PA, 2018,

    Acoustic SLAM

    , IEEE/ACM Transactions on Audio, Speech and Language Processing, Vol: 26, Pages: 1484-1498, ISSN: 2329-9290

    An algorithm is presented that enables devices equipped with microphones, such as robots, to move within their environment in order to explore, adapt to and interact with sound sources of interest. Acoustic scene mapping creates a 3D representation of the positional information of sound sources across time and space. In practice, positional source information is only provided by Direction-of-Arrival (DoA) estimates of the source directions; the source-sensor range is typically difficult to obtain. DoA estimates are also adversely affected by reverberation, noise, and interference, leading to errors in source location estimation and consequent false DoA estimates. Moroever, many acoustic sources, such as human talkers, are not continuously active, such that periods of inactivity lead to missing DoA estimates. Withal, the DoA estimates are specified relative to the observer's sensor location and orientation. Accurate positional information about the observer therefore is crucial. This paper proposes Acoustic Simultaneous Localization and Mapping (aSLAM), which uses acoustic signals to simultaneously map the 3D positions of multiple sound sources whilst passively localizing the observer within the scene map. The performance of aSLAM is analyzed and evaluated using a series of realistic simulations. Results are presented to show the impact of the observer motion and sound source localization accuracy.

  • Journal article
    Shi J, Liu L, Gunduz D, Ling Cet al., 2018,

    Polar codes and polar lattices for the Heegard-Berger problem

    , IEEE Transactions on Communications, Vol: 66, Pages: 3760-3771, ISSN: 0090-6778

    Explicit coding schemes are proposed to achieve the rate-distortion function of the Heegard-Berger problem using polar codes. Specifically, a nested polar code construction is employed to achieve the rate-distortion function for doublysymmetric binary sources when the side information may be absent. The nested structure contains two optimal polar codes for lossy source coding and channel coding, respectively. Moreover, a similar nested polar lattice construction is employed when the source and the side information are jointly Gaussian. The proposed polar lattice is constructed by nesting a quantization polar lattice and a capacity-achieving polar lattice for the additive white Gaussian noise channel.

  • Journal article
    Evers C, Habets EAP, Gannot S, Naylor PAet al., 2018,

    DoA reliability for distributed acoustic tracking

    , IEEE Signal Processing Letters, Vol: 25, Pages: 1320-1324, ISSN: 1070-9908

    Distributed acoustic tracking estimates the trajectories of source positions using an acoustic sensor network. As it is often difficult to estimate the source-sensor range from individual nodes, the source positions have to be inferred from Direction of Arrival (DoA) estimates. Due to reverberation and noise, the sound field becomes increasingly diffuse with increasing source-sensor distance, leading to decreased DoA estimation accuracy. To distinguish between accurate and uncertain DoA estimates, this paper proposes to incorporate the Coherent-to-Diffuse Ratio as a measure of DoA reliability for single-source tracking. It is shown that the source positions therefore can be probabilistically triangulated by exploiting the spatial diversity of all nodes.

  • Journal article
    Cheng H, Xia Y, Huang Y, Yang L, Mandic DPet al., 2018,

    A Normalized Complex LMS Based Blind I/Q Imbalance Compensator for GFDM Receivers and Its Full Second-Order Performance Analysis

    , IEEE TRANSACTIONS ON SIGNAL PROCESSING, Vol: 66, Pages: 4701-4712, ISSN: 1053-587X
  • Journal article
    Clerckx B, Costanzo A, Georgiadis A, Carvalho NBet al., 2018,

    Toward 1G Mobile Power Networks

    , IEEE MICROWAVE MAGAZINE, Vol: 19, Pages: 69-82, ISSN: 1527-3342
  • Conference paper
    Löllmann HW, Evers C, Schmidt A, Mellmann H, Barfuss H, Naylor PA, Kellermann Wet al., 2018,

    The LOCATA challenge data corpus for acoustic source localization and tracking

    , IEEE Sensor Array and Multichannel Signal Processing Workshop 2018, Publisher: IEEE, ISSN: 2151-870X

    Algorithms for acoustic source localization andtracking are essential for a wide range of applications suchas personal assistants, smart homes, tele-conferencing systems,hearing aids, or autonomous systems. Numerous algorithms havebeen proposed for this purpose which, however, are not evaluatedand compared against each other by using a common database sofar. The IEEE-AASP Challenge on sound source localization andtracking (LOCATA) provides a novel, comprehensive data corpusfor the objective benchmarking of state-of-the-art algorithmson sound source localization and tracking. The data corpuscomprises six tasks ranging from the localization of a singlestatic sound source with a static microphone array to the trackingof multiple moving speakers with a moving microphone array.It contains real-world multichannel audio recordings, obtainedby hearing aids, microphones integrated in a robot head, aplanar and a spherical microphone array in an enclosed acousticenvironment as well as positional information about the involvedarrays and sound sources represented by moving human talkersor static loudspeakers.

  • Conference paper
    Hafezi S, Moore AH, Naylor PA, 2018,

    ROBUST SOURCE COUNTING AND ACOUSTIC DOA ESTIMATION USING DENSITY-BASED CLUSTERING

    , 10th IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), Publisher: IEEE, Pages: 395-399, ISSN: 1551-2282
  • Journal article
    Talebi SP, Werner S, Mandic DP, 2018,

    Distributed Adaptive Filtering of alpha-Stable Signals

    , IEEE SIGNAL PROCESSING LETTERS, Vol: 25, Pages: 1450-1454, ISSN: 1070-9908
  • Journal article
    Xia Y, Douglas SC, Mandic DP, 2018,

    A perspective on CLMS as a deficient length augmented CLMS: Dealing with second order noncircularity

    , SIGNAL PROCESSING, Vol: 149, Pages: 236-245, ISSN: 0165-1684
  • Journal article
    Constantinescu MA, Lee S-L, Ernst S, Hemakom A, Mandic D, Yang G-Zet al., 2018,

    Probabilistic guidance for catheter tip motion in cardiac ablation procedures

    , Medical Image Analysis, Vol: 47, Pages: 1-14, ISSN: 1361-8415

    Radiofrequency catheter ablation is one of the commonly available therapeutic methods for patients suffering from cardiac arrhythmias. The prerequisite of successful ablation is sufficient energy delivery at the target site. However, cardiac and respiratory motion, coupled with endocardial irregularities, can cause catheter drift and dispersion of the radiofrequency energy, thus prolonging procedure time, damaging adjacent tissue, and leading to electrical reconnection of temporarily ablated regions. Therefore, positional accuracy and stability of the catheter tip during energy delivery is of great importance for the outcome of the procedure. This paper presents an analytical scheme for assessing catheter tip stability, whereby a sequence of catheter tip motion recorded at sparse locations on the endocardium is decomposed. The spatial sliding component along the endocardial wall is extracted from the recording and maximal slippage and its associated probability are computed at each mapping point. Finally, a global map is generated, allowing the assessment of potential areas that are compromised by tip slippage. The proposed framework was applied to 40 retrospective studies of congenital heart disease patients and further validated on phantom data and simulations. The results show a good correlation with other intraoperative factors, such as catheter tip contact force amplitude and orientation, and with clinically documented anatomical areas of high catheter tip instability.

  • Journal article
    Li Z, Xia Y, Pei W, Wang K, Mandic Det al., 2018,

    An Augmented Nonlinear LMS for Digital Self-Interference Cancellation in Full-Duplex Direct-Conversion Transceivers

    , IEEE Transactions on Signal Processing, Vol: 66, Pages: 4065-4078, ISSN: 1053-587X

    In future full-duplex communications, the cancellation of self-interference (SI) arising from hardware nonidealities will play an important role in the design of mobile-scale devices. To this end, we introduce an optimal digital SI cancellation solution for shared-antenna-based direct-conversion transceivers. To establish that the underlying widely linear signal model is not adequate for strong transmit signals, the impact of various circuit imperfections, including power amplifier distortion, frequency-dependent I/Q imbalance, quantization noise, and thermal noise, on the performance of the conventional augmented least mean square (LMS) based SI canceller, is analyzed. In order to achieve a sufficient signal-to-interference-plus-noise ratio when the nonlinear SI components are not negligible, we propose an augmented nonlinear LMS based SI canceller for a joint cancellation of both the linear and nonlinear SI components by virtue of a widely nonlinear model fit. A rigorous mean and mean square performance evaluation is conducted to justify the performance advantages of the proposed scheme over the conventional augmented LMS solution. Simulations on orthogonal frequency division multiplexing-based wireless local area network standard compliant waveforms support the analysis.

  • Journal article
    Yang G, Yu S, Hao D, Slabaugh G, Dragotti PL, Ye X, Liu F, Arridge S, Keegan J, Guo Y, Firmin Det al., 2018,

    DAGAN: deep de-aliasing generative adversarial networks for fast compressed sensing MRI reconstruction

    , IEEE Transactions on Medical Imaging, Vol: 37, Pages: 1310-1321, ISSN: 0278-0062

    Compressed Sensing Magnetic Resonance Imaging (CS-MRI) enables fast acquisition, which is highly desirable for numerous clinical applications. This can not only reduce the scanning cost and ease patient burden, but also potentially reduce motion artefacts and the effect of contrast washout, thus yielding better image quality. Different from parallel imaging based fast MRI, which utilises multiple coils to simultaneously receive MR signals, CS-MRI breaks the Nyquist-Shannon sampling barrier to reconstruct MRI images with much less required raw data. This paper provides a deep learning based strategy for reconstruction of CS-MRI, and bridges a substantial gap between conventional non-learning methods working only on data from a single image, and prior knowledge from large training datasets. In particular, a novel conditional Generative Adversarial Networks-based model (DAGAN) is proposed to reconstruct CS-MRI. In our DAGAN architecture, we have designed a refinement learning method to stabilise our U-Net based generator, which provides an endto-end network to reduce aliasing artefacts. To better preserve texture and edges in the reconstruction, we have coupled the adversarial loss with an innovative content loss. In addition, we incorporate frequency domain information to enforce similarity in both the image and frequency domains. We have performed comprehensive comparison studies with both conventional CSMRI reconstruction methods and newly investigated deep learning approaches. Compared to these methods, our DAGAN method provides superior reconstruction with preserved perceptual image details. Furthermore, each image is reconstructed in about 5 ms, which is suitable for real-time processing.

  • Journal article
    Mao Y, Clerckx B, Li VOK, 2018,

    Rate-splitting multiple access for downlink communication systems: bridging, generalizing and outperforming SDMA and NOMA

    , EURASIP Journal on Wireless Communications and Networking, Vol: 2018, ISSN: 1687-1472

    Space-division multiple access (SDMA) utilizes linear precoding to separate users in the spatial domain and relies on fully treating any residual multi-user interference as noise. Non-orthogonal multiple access (NOMA) uses linearly precoded superposition coding with successive interference cancellation (SIC) to superpose users in the power domain and relies on user grouping and ordering to enforce some users to fully decode and cancel interference created by other users.In this paper, we argue that to efficiently cope with the high throughput, heterogeneity of quality of service (QoS), and massive connectivity requirements of future multi-antenna wireless networks, multiple access design needs to depart from those two extreme interference management strategies, namely fully treat interference as noise (as in SDMA) and fully decode interference (as in NOMA).Considering a multiple-input single-output broadcast channel, we develop a novel multiple access framework, called rate-splitting multiple access (RSMA). RSMA is a more general and more powerful multiple access for downlink multi-antenna systems that contains SDMA and NOMA as special cases. RSMA relies on linearly precoded rate-splitting with SIC to decode part of the interference and treat the remaining part of the interference as noise. This capability of RSMA to partially decode interference and partially treat interference as noise enables to softly bridge the two extremes of fully decoding interference and treating interference as noise and provides room for rate and QoS enhancements and complexity reduction.The three multiple access schemes are compared, and extensive numerical results show that RSMA provides a smooth transition between SDMA and NOMA and outperforms them both in a wide range of network loads (underloaded and overloaded regimes) and user deployments (with a diversity of channel directions, channel strengths, and qualities of channel state information at the transmitter). Moreover, RSMA provid

  • Journal article
    Voulodimos A, Doulamis N, Bebis G, Stathaki Tet al., 2018,

    Recent Developments in Deep Learning for Engineering Applications

    , COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE, Vol: 2018, ISSN: 1687-5265
  • Journal article
    Kanna S, von Rosenberg W, Goverdovsky V, Constantinides AG, Mandic DPet al., 2018,

    Bringing Wearable Sensors into the Classroom: A Participatory Approach

    , IEEE SIGNAL PROCESSING MAGAZINE, Vol: 35, Pages: 110-+, ISSN: 1053-5888
  • Journal article
    Dionelis N, Brookes DM, 2018,

    Phase-aware single-channel speech enhancement with modulation-domain Kalman filtering

    , IEEE Transactions on Audio, Speech and Language Processing, Vol: 26, Pages: 937-950, ISSN: 1558-7916

    We present a speech enhancement algorithm that performs modulation-domain Kalman filtering to track the speech phase using circular statistics, along with the log-spectra of speech and noise. In the proposed algorithm, the speech phase posterior is used to create an enhanced speech phase spectrum for the signal reconstruction of speech. The Kalman filter prediction step separately models the temporal inter-frame correlation of the speech and noise spectral log-amplitudes and of the speech phase, while the Kalman filter update step models their nonlinear relations under the assumption that speech and noise add in the complex short-time Fourier transform domain. The phase-sensitive enhancement algorithm is evaluated with speech quality and intelligibility metrics, using a variety of noise types over a range of SNRs. Instrumental measures predict that tracking the speech log-spectrum and phase with modulation-domain Kalman filtering leads to consistent improvements in speech quality, over both conventional enhancement algorithms and other algorithms that perform modulation-domain Kalman filtering.

  • Journal article
    Normahani P, Makwana N, von Rosenberg W, Syed S, Mandic D, Goverdovsky V, Standfield N, Jaffer Uet al., 2018,

    Self-assessment of surgical ward crisis management using video replay augmented with stress biofeedback

    , Patient Safety in Surgery, Vol: 12, ISSN: 1754-9493

    BackgroundWe aimed to explore the feasibility and attitudes towards using video replay augmented with real time stress quantification for the self-assessment of clinical skills during simulated surgical ward crisis management.Methods22 clinicians participated in 3 different simulated ward based scenarios of deteriorating post-operative patients. Continuous ECG recordings were made for all participants to monitor stress levels using heart rate variability (HRV) indices. Video recordings of simulated scenarios augmented with real time stress biofeedback were replayed to participants. They were then asked to self-assess their performance using an objective assessment tool. Participants’attitudes were explored using a post study questionnaire. ResultsUsing HRV stress indices, we demonstrated higher stress levels in novice participants. Self-assessment scores were significantly higherin more experienced participants. Overall, participants felt that video replay andaugmented stress biofeedback were useful in self-assessment. ConclusionSelf-assessment using an objective self-assessment tool alongside video replay augmented with stress biofeedback is feasible in a simulated setting and well liked by participants.

  • Journal article
    Zhang P, Gan L, Ling C, Sun Set al., 2018,

    Uniform recovery bounds for structured random matrices in corrupted compressed sensing

    , IEEE Transactions on Signal Processing, Vol: 66, Pages: 2086-2097, ISSN: 1053-587X

    We study the problem of recovering an s-sparse signal x* ∈ C n from corrupted measurements y = Ax* + z* + w, where z* ∈ C m is a k-sparse corruption vector whose nonzero entries may be arbitrarily large and w ∈ C m is a dense noise with bounded energy. The aim is to exactly and stably recover the sparse signal with tractable optimization programs. In this paper, we prove the uniform recovery guarantee of this problem for two classes of structured sensing matrices. The first class can be expressed as the product of a unit-norm tight frame (UTF), a random diagonal matrix, and a bounded columnwise orthonormal matrix (e.g., partial random circulant matrix). When the UTF is bounded (i.e. μ(U) ~ 1/√m), we prove that with high probability, one can recover an s-sparse signal exactly and stably by l 1 minimization programs even if the measurements are corrupted by a sparse vector, provided m = O(s log 2 s log 2 n) and the sparsity level k of the corruption is a constant fraction of the total number of measurements. The second class considers a randomly subsampled orthonormal matrix (e.g., random Fourier matrix). We prove the uniform recovery guarantee provided that the corruption is sparse on certain sparsifying domain. Numerous simulation results are also presented to verify and complement the theoretical results.

  • Journal article
    Dragotti PL, 2018,

    A Brief Message From the New Editor-in-Chief

    , IEEE TRANSACTIONS ON SIGNAL PROCESSING, Vol: 66, Pages: 1952-1952, ISSN: 1053-587X
  • Journal article
    Zheng M, Chen W, Ling C, 2018,

    Polar coding for the cognitive interference channel with confidential messages

    , IEEE Journal on Selected Areas in Communications, Vol: 36, Pages: 762-774, ISSN: 0733-8716

    In this paper, we propose a low-complexity, secrecy capacity achieving polar coding scheme for the cognitive interference channel with confidential messages (CICC) under the strong secrecy criterion. Existing polar coding schemes for interference channels rely on the use of polar codes for the multiple access channel, the code construction problem of which can be complicated. We show that the whole secrecy capacity region of the CICC can be achieved by simple point-to-point polar codes due to the cognitivity, and our proposed scheme requires the minimum rate of randomness at the encoder.

  • Journal article
    Lu Y, Onativia J, Dragotti P, 2018,

    Sparse representation in Fourier and local bases Using ProSparse: a probabilistic analysis

    , IEEE Transactions on Information Theory, Vol: 64, Pages: 2639-2647, ISSN: 0018-9448

    Finding the sparse representation of a signal in an overcomplete dictionary has attracted a lot of attention over the past years. This paper studies ProSparse, a new polynomial complexity algorithm that solves the sparse representation problem when the underlying dictionary is the union of a Vandermonde matrix and a banded matrix. Unlike our previous work which establishes deterministic (worst-case) sparsity bounds for ProSparse to succeed, this paper presents a probabilistic average-case analysis of the algorithm. Based on a generatingfunction approach, closed-form expressions for the exact success probabilities of ProSparse are given. The success probabilities are also analyzed in the high-dimensional regime. This asymptotic analysis characterizes a sharp phase transition phenomenon regarding the performance of the algorithm.

  • Journal article
    Zheng M, Tao M, Chen W, Ling Cet al., 2018,

    Secure polar coding for the two-way wiretap channel

    , IEEE Access, Vol: 6, Pages: 21731-21744, ISSN: 2169-3536

    In this paper, we consider the problem of polar coding for secure communications over the two-way wiretap channel, where two legitimate users communicate with each other simultaneously, while a passive eavesdropper overhears a combination of their exchanged signals. We design a low complexity polar coded cooperative jamming scheme that achieves the whole secrecy rate region of the general two-way wiretap channel under the strong secrecy criterion. The chaining method is used to make proper alignment of polar indices. The randomness required to be shared between two legitimate users is treated as a limited resource and we show that its rate can be made negligible by increasing the blocklength and the number of chained blocks. For the special case when the eavesdropper channel is degraded with respect to the legitimate ones, a simplified scheme is proposed which can simultaneously ensure reliability and weak secrecy within a single transmission block.

  • Journal article
    Liu L, Yan Y, Ling C, 2018,

    Achieving secrecy capacity of the Gaussian wiretap channel with polar lattices

    , IEEE Transactions on Information Theory, Vol: 64, Pages: 1647-1665, ISSN: 0018-9448

    In this paper, an explicit scheme of wiretap coding based on polar lattices is proposed to achieve the secrecy capacity of the additive white Gaussian noise (AWGN) wiretap channel. First, polar lattices are used to construct secrecy-good lattices for the mod-Λ s Gaussian wiretap channel (GWC). Then, we propose an explicit shaping scheme to remove this mod-Λ s front end and extend polar lattices to the genuine GWC. The shaping technique is based on the lattice Gaussian distribution, which leads to a binary asymmetric channel at each level for the multilevel lattice codes. By employing the asymmetric polar coding technique, we construct an AWGN-good lattice and a secrecy-good lattice with optimal shaping simultaneously. As a result, the encoding complexity for the sender and the decoding complexity for the legitimate receiver are both O(N log N log (log N)). The proposed scheme is proven to be semantically secure.

  • Journal article
    Alexiadis DS, Mitianoudis N, Stathaki T, 2018,

    Multidimensional directional steerable filters - Theory and application to 3D flow estimation

    , IMAGE AND VISION COMPUTING, Vol: 71, Pages: 38-67, ISSN: 0262-8856
  • Journal article
    Park J, Clerckx B, Song C, Wu Yet al., 2018,

    An Analysis of the Optimum Node Density for Simultaneous Wireless Information and Power Transfer in Ad Hoc Networks

    , IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol: 67, Pages: 2713-2726, ISSN: 0018-9545

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