Linh Tran

• PhD
• Lecturer at Posts and Telecommunications Institute of Technology

Vietnamese is an under-resourced language. The requirement for a large-scale and high-quality Vietnamese speech corpus increases on demand. We introduce a new large-scale Vietnamese speech corpus with 100.5 h collected from various audio sources in the Internet. The raw collected audio was processed to obtain clean speech. Transcription of the clea...

Acoustic coupling between microphone and loudspeaker is a significant problem in open-fit digital hearing aids. An open-fit compared to a close-fit hearing aid significantly lowers the signal quality and limits the achievable maximum stable gain. Adaptive feedback cancellation (AFC) enables an efficient approach to reduce the impact of acoustic cou...

In adaptive feedback cancellation (AFC) methods, the step-size plays an important role in controlling the convergence speed of an adaptive filter in the feedback canceller path. The selection of this step-size provides a compromise between a low steady-state error and a fast convergence rate. The use of a variable step-size (VSS) is a potential sol...

Recently it has been proposed to use a fixed beamformer to cancel the acoustic feedback for a custom earpiece with multiple integrated microphones and loudspeakers. By steering a spatial null in the direction of the hearing aid loudspeaker theoretically perfect feedback cancellation can be achieved. In contrast to previous approaches that constrain...

Numerous adaptive feedback cancellation (AFC) algorithms are used in open-fitting and in-ear hearing aid devices (HADs) in order to avoid the possible annoying howling sounds. Recently, a hybrid AFC (H-AFC) scheme that shortened the recovering time from howling was proposed. It consists of a switched combination adaptive filter controlled by a stab...

A challenge in hearing aids is adaptive feedback control which often uses an adaptive filter to estimate the feedback path. This estimate of the feedback path usually results in a bias due to the correlation between the loudspeaker signal and the incoming signal. The prediction error method (PEM) is a popular method for reducing this bias for adapt...

Adaptive feedback cancellation (AFC) techniques are common in modern hearing aid devices (HADs) since these techniques have been successful in increasing the stable gain. Accordingly, there has been a significant effort to improve AFC technology, especially for open-fitting and in-ear HADs, for which howling is more prevalent due to the large acous...

The affine projection algorithm (APA) is commonly used for adaptive filtering in acoustic echo cancellation (AEC) due to its higher convergence and tracking rate compared to the conventional normalized least mean squares (NLMS) algorithm, especially for spectrally coloured incoming signals. However, its application to adaptive feedback control (AFC...

Commonly adaptive filters are used to reduce the acoustic feedback in hearing aids. While theoretically allowing for perfect cancellation of the feedback signal, in practice the adaptive filter solution is typically biased due to the closed-loop hearing aid system. In contrast to conventional behind-the-ear hearing aids, in this paper we consider a...

The proportionate normalized least-mean-squares (PNLMS) algorithm is commonly used in acoustic echo cancellation (AEC) context. It provides faster initial convergence and tracking rates compared to the NLMS algorithm for the case of sparse echo impulse responses. The improved PNLMS algorithm (IPNLMS) has been proven to be more powerful than PNLMS b...

Commonly adaptive filters are used to reduce the acoustic feedback in hearing aids. While theoretically allowing for perfect cancellation of the feedback signal, in practice the adaptive filter solution is typically biased due to the closed-loop hearing aid system. In contrast to conventional behind-the-ear hearing aids, in this paper we consider a...

Variable step-size (VSS) schemes are popular to use in acoustic echo cancellation (AEC) contexts. However, their effective implementation in adaptive feedback cancellation (AFC) for hearing aids is still challenging due to the correlation between microphone and loudspeaker signals. We propose an improved practical VSS algorithm (IPVSS) which uses a...

In order to reduce acoustic feedback in hearing aids, adaptive filters are commonly used to estimate the feedback contribution in the microphone(s). While theoretically allowing for perfect feedback cancellation, in practice the solution is typically biased due to the closed-loop acoustical system. In this paper, we propose to use a fixed beamforme...

Prediction error method (PEM) is popularly applied to acoustic feedback cancellation (AFC) in hearing aids. Commonly, this method uses normalized least mean square (NLMS) adaptive filter to estimate the coefficients of the real feedback path. A disadvantage of NLMS algorithm is to provide a slow convergence rate when coloured incoming signals are u...

In adaptive feedback cancellation an adaptive filter is used to model the acoustic feedback path between the hearing aid receiver and the microphone. An important parameter for adaptive filters is the step-size, providing a trade-off between fast convergence and low steady-state misalignment. In order to achieve both fast convergence as well as low...

The limiting feature of hearing aids is acoustic feedback. This feedback problem has been approached by using an acoustic feedback canceller. This well known identification in a loop problem, will give a biased solution due to correlation between the desired and loudspeaker signals. Speech and music signals have long tails in the correlation. As a...

Affine projection algorithms (APA) have been widely employed for acoustic echo cancellation (AEC) since they provide a natural trade-off between convergence speed and computational complexity. However, their application in Acoustic Feedback Cancellation (AFC) in hearing aids so far has been limited due to lack of performance improvement in one micr...

Like in GSM network the co-channel interference (CCI) is popular in EDGE network due to the problem of reusing frequency in distant cells. Although the distance between cells using the same frequencies is quite far but CCI still causes significant effect to the channel capacity rather than noise. In fact, many solutions were introduced to reduce th...

The capacity of the popular GSM network is limited by co-channel interference (CCI) rather than noise. Nowadays, some solutions such as a receiver with multiple antennas (MIMO) or a receiver with single antenna interference cancellation (SAIC) have been applied to cancel the CCI as well as to improve the network capacity. According to this paper, a...

The capacity of the 2^nd generation TDMA cellular radio networks such as GSM and EDGE is limited by co-channel interference (CCI) rather than noise. There are some solutions to cancel the CCI and improve the network capacity such as a receiver with multiple antennas (MIMO), or a receiver with single antenna interference cancellation (SAIC...