
Bruce Xiao WangThe Hong Kong Polytechnic University | PolyU · Department of English and Communication
Bruce Xiao Wang
PhD in Linguistics (forensic speech science)
About
35
Publications
3,098
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Citations
Introduction
Additional affiliations
September 2021 - July 2022
January 2019 - June 2020
Position
- Research Assistant
Description
- - Data preparation and modelling of phonetic features for forensic voice comparison purposes - Revisiting evidential values of Cantonese and Mandarin tones - Create audio stimulus for psycholinguistic research - Prepare tutorial materials for English Phonetics module (ENGL2166)
Education
July 2017 - December 2021
September 2013 - January 2015
Publications
Publications (35)
In forensic comparison sciences, experts are required to compare samples of known and unknown origin to evaluate the strength of the evidence assuming they came from the same- and different-sources. The application of valid (if the method measures what it is intended to) and reliable (if that method produces consistent results) forensic methods is...
1 Phonetic theories provide frameworks that 2 help us understand how speech sounds are 3 produced, transmitted, and perceived. 4 Whether phonetic theories can predict 5 speaker discrimination performance in the 6 context of forensic voice comparison is an 7 important issue that requires investigation. 8 This paper evaluates the speaker-9 discrimina...
Forensic voice comparison (FVC) involving bilingual speakers presents a substantial challenge to forensic practitioners. Previous FVC research suggests that discriminatory power is, unsurprisingly, weaker in language mismatch conditions than in the language match conditions. The present paper extends on previous work examining bilingual speakers to...
A growing number of studies in forensic voice comparison have explored how elements of phonetic analysis and automatic speaker recognition systems may be integrated for optimal speaker discrimination performance. However, few studies have investigated the evidential value of long-term speech features using forensically-relevant speech data. This pa...
Fundamental frequency (F0) has been widely studied and used in the context of speaker discrimination and forensic voice comparison casework, but most previous studies focused on long-term F0 statistics. Lexical tone, the linguistically structured and dynamic aspects (F0), has received much less research attention. A main methodological issue lies o...
What matters often is not what you say, but how you say it. Prosody portrays the suprasegmental features of speech and serves as an important role in this communicative function. While the encoding and decoding of prosodic features seems to be straightforward for the typically developing (TD) individuals, many studies have reported impaired perform...
During conversations, individuals adapt their speech in response to their partners, a phenomenon known as 'speech accommodation'. Communication Accommodation Theory (CAT) suggests that this adaptation is employed to manipulate social distance, and it's influenced by the impression we have of our conversation partner. While there's a growing body of...
Investigating the evidential value of filled pauses in cross-language forensic voice comparison Filled pauses (FPs) are known for their speaker-specific characteristics, displaying low within-speaker variability and demonstrating promising speaker-discriminatory power in forensic voice comparison (FVC) (e.g., Hughes et al., 2016). However, the evid...
This pilot study aims to estimate the articulatory space of Cantonese-speaking healthy adults using UTI, and to investigate if articulatory space would be affected by gender and phonological contexts.
Purpose
The current study investigated English prosodic focus marking by autistic and typically developing (TD) Cantonese trilingual children, and examined the potential differences in this regard compared to native English-speaking children.
Method
Forty-eight participants were recruited with 16 speakers for each of the three groups (Cantonese-sp...
In recent years, Mel-frequency cepstral coefficients (MFCCs; Davis and Mermelstein, 1980) have been widely used as the input features of semi-automatic (Nolan & Grigoras, 2005) forensic voice comparison (FVC) systems, and some studies have shown that MFCC features yield better speaker discriminatory performance (e.g., lower EER and/or Cllr) than tr...
The current study investigated the production of English prosody (i.e., focus marking) of trilingual Cantonese children with autism spectrum disorder (ASD) and their typically developing (TD) peers (i.e., Cantonese and American English children without ASD) using declarative questions. Speech materials were segmented at word and syllable levels, an...
Recent empirical studies have highlighted the large degree of analytic flexibility in data analysis which can lead to substantially different conclusions based on the same data set. Thus, researchers have expressed their concerns that these researcher degrees of freedom might facilitate bias and can lead to claims that do not stand the test of time...
In data-driven forensic voice comparison (FVC), empirical testing of a system is an essential step to demonstrate validity and reliability. Numerous studies have focused on improving system validity, while studies of reliability are comparatively limited. In the present study, simulated scores were generated from i-vector and GMM-UBM automatic spea...
In data-driven forensic voice comparison (FVC), empirical testing of a system is an essential step to demonstrate validity (i.e. how well the system performs the task) and reliability (i.e. whether the system would yield the same result if the analysis were repeated). The present study focuses on system reliability, aiming to reduce the degree of u...
Forensic validation tends to focus on the overall performance of methods under casework conditions. This implicitly focuses the expert’s attention on discriminability (see Smith & Neal 2021), with different methods chosen, or decisions made, based low values for the validity metric used. In this paper, we argue against this view. Rather, we believe...
The likelihood ratio (LR) framework has been widely adopted in voice (and other forensic) evidence evaluation. However, in developing any forensic comparison system, it is necessary to make subjective and pragmatic decisions, which in turn may affect the results that system produces. One such decision relates to not only the size of the samples use...
In data-driven forensic voice comparison, sample size is an issue which can have substantial effects on system output. Numerous calibration methods have been developed and some have been proposed as solutions to sample size issues. In this paper, we test four calibration methods (i.e. logistic regression, regularised logistic regression, Bayesian m...
The current study simulated skewed scores from an empirical study (Wang et al., 2019) to test the susceptibility of four calibration methods (i.e. logistic regression (Brümmer et al., 2007), regularised logistic (rlogistic) regression (Morrison & Poh, 2018), empirical lower and upper bound (ELUB, Vergeer et al., 2016) and Bayesian model (Brümmer &...
Within the field of forensic voice comparison (FVC), there is growing pressure for experts to demonstrate the validity and reliability of the conclusions they reach in casework. One benefit of a fully data-driven approach that utilises databases of speakers to compute numerical likelihood ratios (LRs) is that it is possible to estimate validity and...
The likelihood-ratio (LR) framework has been employed in many forensic voice comparison studies to test the speaker-specificity of individual vowels and phonetic sequences (e.g. Morrison, 2009; Zhang, Morrison & Thiruvaran, 2011; Rose & Wang, 2016). Other studies have looked at the effects of sample size on LR outputs (e.g. Hughes, 2014, Hughes & F...
An experiment relating to estimation of strength of evidence in forensic voice comparison is described which explores the use of F-pattern and tonal F0 trajectories extracted over a disyllabic word as a whole, rather than over individual monosyllables as conventionally practiced. The first three formants and tonal F0 (measured in Hz) of Cantonese d...