Identification of Transient Speech Using Wavelet Transforms

It is generally believed that abrupt stimulus changes, which in speech may be time-varying frequency edges associated with consonants, transitions between consonants and vowels and transitions within vowels are critical to the perception of speech by humans and for speech recognition by machines. Noise affects speech transitions more than it affects quasi-steady-state speech. I believe that identifying and selectively amplifying speech transitions may enhance the intelligibility of speech in noisy conditions. The purpose of this study is to evaluate the use of wavelet transforms to identify speech transitions. Using wavelet transforms may be computationally efficient and allow for real-time applications. The discrete wavelet transform (DWT), stationary wavelet transform (SWT) and wavelet packets (WP) are evaluated. Wavelet analysis is combined with variable frame rate processing to improve the identification process. Variable frame rate can identify time segments when speech feature vectors are changing rapidly and when they are relatively stationary. Energy profiles for words, which show the energy in each node of a speech signal decomposed using wavelets, are used to identify nodes that include predominately transient information and nodes that include predominately quasi-steady-state information, and these are used to synthesize transient and quasi-steady-state speech components. These speech components are estimates of the tonal and nontonal speech components, which Yoo et al identified using time-varying band-pass filters. Comparison of spectra, a listening test and mean-squared-errors between the transient components synthesized using wavelets and Yoo's nontonal components indicated that wavelet packets identified the best estimates of Yoo's components. An algorithm that incorporates variable frame rate analysis into wavelet packet analysis is proposed. The development of this algorithm involves the processes of choosing a wavelet function and a decomposition level to be used. The algorithm itself has 4 steps: wavelet packet decomposition; classification of terminal nodes; incorporation of variable frame rate processing; synthesis of speech components. Combining wavelet analysis with variable frame rate analysis provides the best estimates of Yoo's speech components

Evaluating The Psychometric Properties of the Clinical Assessment Tool Used in The Midwifery Programme In Botswana

Background: Clinical assesssment tools play an essential role in clinical practice and assessment. Clinical assessment tools have to be evaluated for pyschometric properties to enhance objectivity and fairness when evaluating students. Reliability and validity are considered the main psychometric properties of clinical assessment tools. However, determining the psychometric properties of clinical assessment tools still remains a major problem. Hence, some tools are designed and used without adequate assessment of their reliability and validity. There is no evidence of the psychometric properties, mainly internal consistency, reliability and content validity of the clinical assessment tool used in Midwifery Programme in Botswana. Aim/Purpose: The aim of the study was to evaluate the internal consistency reliability and content validity psychometric properties of the clinical assessment tool used in the Midwifery Programme in Botswana. Design: A methodological design was used to evaluate the internal consistency reliability and content validity psychometric properties of the clinical assessment tool used in the Midwifery Programme in Botswana. Research process: Data was collected from the completed clinical assessment tools which were used to assess midwifery students registered for intrapartum care (MID 421) in semester 2 and intrapartum care practicum (MID 543) in semester 4 in 2019, from the midwifery training schools, n=114. Data collected from these clinical assessment tools was captured and analyzed using the downloaded IBM® Statistical Package for the Social Sciences (SPSS) software, version 25. Inter-item analysis and the corrected item–total correlation were calculated to determine the internal consistency reliability of the clinical assessment tool used in midifery programme. Cronbach’s alpha was used to determine the reliability of the entire clinical assessment tool. The Subject Matter Expects in midwifery working in the academic field and those working in the Nursing and Midwifery Council in Botswana, were used to evaluate the content validity regarding the relevance and clarity of the competencies in the clinical assessment tool. The Content Validity Index (CVI), Item Content Validity Index (I-CVI), Content Validity Ratio (CVR), the overall scale (S-CVI/Ave) and Scale Content Validity Index using Universal Agreement (S-CVI-UA) were calculated to determine the content validity of the clinical assessment tool used in the Midwifery Programme in Botswana. Results: The results of this study with regard to internal consistency reliability, revealed an overall Cronbach’s alpha of the clinical assessment tool of 0.837. The results of this study, with regard to content validity, revealed an overall CVR of 0.95 and an overall CVI of 0.97. The I-CVI value of the competencies for content validity ranged from 0.8 to 1. The S-CVI/Ave and the S-CVI/UA values of the competencies for content validity were 0.97 and 0.75 respectively. Conclusion: The clinical assessment tool used in the Midwifery Programme in Botswana is reliable and valid. However, there is a need to review some of the competencies to improve its internal consistency reliability and content validity. Keywords: Clinical Assessment, Clinical Assessment Tool, Midwifery Training Institutions, Midwifery Students, Midwifery Programme, Botswana, Reliability, Validity, Psychometric Properties.Dissertation (MNSc)--University of Pretoria, 2021.Nursing ScienceMNScUnrestricte

ENHANCEMENT OF SPEECH INTELLIGIBILITY USING SPEECH TRANSIENTS EXTRACTED BY A WAVELET PACKET-BASED REAL-TIME ALGORITHM

Studies have shown that transient speech, which is associated with consonants, transitions between consonants and vowels, and transitions within some vowels, is an important cue for identifying and discriminating speech sounds. However, compared to the relatively steady-state vowel segments of speech, transient speech has much lower energy and thus is easily masked by background noise. Emphasis of transient speech can improve the intelligibility of speech in background noise, but methods to demonstrate this improvement have either identified transient speech manually or proposed algorithms that cannot be implemented to run in real-time.We have developed an algorithm to automatically extract transient speech in real-time. The algorithm involves the use of a function, which we term the transitivity function, to characterize the rate of change of wavelet coefficients of a wavelet packet transform representation of a speech signal. The transitivity function is large and positive when a signal is changing rapidly and small when a signal is in steady state. Two different definitions of the transitivity function, one based on the short-time energy and the other on Mel-frequency cepstral coefficients, were evaluated experimentally, and the MFCC-based transitivity function produced better results. The extracted transient speech signal is used to create modified speech by combining it with original speech.To facilitate comparison of our transient and modified speech to speech processed using methods proposed by other researcher to emphasize transients, we developed three indices. The indices are used to characterize the extent to which a speech modification/processing method emphasizes (1) a particular region of speech, (2) consonants relative to, and (3) onsets and offsets of formants compared to steady formant. These indices are very useful because they quantify differences in speech signals that are difficult to show using spectrograms, spectra and time-domain waveforms.The transient extraction algorithm includes parameters which when varied influence the intelligibility of the extracted transient speech. The best values for these parameters were selected using psycho-acoustic testing. Measurements of speech intelligibility in background noise using psycho-acoustic testing showed that modified speech was more intelligible than original speech, especially at high noise levels (-20 and -15 dB). The incorporation of a method that automatically identifies and boosts unvoiced speech into the algorithm was evaluated and showed that this method does not result in additional speech intelligibility improvements

The listening talker: A review of human and algorithmic context-induced modifications of speech

International audienceSpeech output technology is finding widespread application, including in scenarios where intelligibility might be compromised - at least for some listeners - by adverse conditions. Unlike most current algorithms, talkers continually adapt their speech patterns as a response to the immediate context of spoken communication, where the type of interlocutor and the environment are the dominant situational factors influencing speech production. Observations of talker behaviour can motivate the design of more robust speech output algorithms. Starting with a listener-oriented categorisation of possible goals for speech modification, this review article summarises the extensive set of behavioural findings related to human speech modification, identifies which factors appear to be beneficial, and goes on to examine previous computational attempts to improve intelligibility in noise. The review concludes by tabulating 46 speech modifications, many of which have yet to be perceptually or algorithmically evaluated. Consequently, the review provides a roadmap for future work in improving the robustness of speech output

The influence of the business environment on Botswana’s public procurement process and its impact on military

Thesis (DPhil)--Stellenbosch University, 2021.ENGLISH ABSTRACT: While limited literature on public procurement exists, not much research has been conducted on how the influence of the business environment on public procurement has impacted on military capability in Botswana. The limited literature has only concentrated on reforms, without much emphasis on evaluating the impact on military capability. In attempting to close this gap, this thesis thoroughly explains the concept of public procurement based on the existing literature. Of importance are the legislative and policy frameworks in Botswana in which public procurement is conducted, as well as their implications for defence procurement. In formulating the possible best practice for defence procurement in Botswana, international perspectives were evaluated,which culminated in a regional perspective of conducting defence procurement. This study sought to address the question:“What needs to be done to ensure a prompt and efficient defence force,while being dependent on public procurement that exists in a complex business environment characterised by a bureaucratic system?” In answering this question, this study contributes to addressing the existing deficiency in the literature, as well as contributing a solution to an existing practical problem.This was a qualitative study in approach, case study by design, and an exploratory study by purpose. The study used interviews with a non-statistical expert purposive sampling technique, as well as document analysis. A deductive approach to data analysis and interpretation was adopted through the application of the systems theory and systems thinking approach as major theories. These were augmented with the organisational buying behaviour and dialectical theories. As the analysis was deductive in approach, the elements of systemic structures as derived from the iceberg model were applied for coding. The study concluded that Botswana’s defence procurement requires total structural reforms, which include proper placement of the procurement function, engagement of civil professionals, the development of a security and defence policy, as well as developing a procurement model that will be in line with striking a balance between defence spending and national development goals in line with the current Fourth Industrial Revolution debate.AFRIKAANSE OPSOMMING: Hoewel daar beperkte literatuur oor openbare bevoorrading bestaan, is daar nog nie veel navorsing gedoen rakende hoe die invloed van die besigheidsomgewing op openbare bevoorrading die verdedigings vermoë in Botswana beïnvloed nie. Die beperkte literatuur het slegs gefokus op hervorming, met min klem op die evaluering van die invloed op verdedigings vermoë. In ’n poging om hierdie gaping te vul, verduidelik hierdie tesis omvattend die konsep van openbare bevoorrading gebaseer op die bestaande literatuur. Die wetgewende en beleidsraamwerke in Botswana waarin openbare bevoorrading onderneem word is belangrik, asook hul implikasies vir verdedigings bevoorrading. Ten einde die beste moontlike praktyke vir verdedigings bevoorrading in Botswana te formuleer, is internasionale perspektiewe getakseer, wat gelei het na’n streeksperspektief tot die onderneming van verdedigings bevoorrading. Hierdie studie het gepoog om die vraag “Wat moet gedoen word om ’n vaardige en doeltreffende verdedigingsmag te verseker terwyl dit afhanklik is van openbare bevoorrading wat bestaan in ’n ingewikkelde besigheidsomgewing wat gekenmerk word deur ’n burokratiese stelsel?” te beantwoord. Deur hierdie vraag te beantwoord, dra hierdie studie daartoe by om die bestaande gebrek in die literatuur aan te spreek, en dra ook by tot ’n oplossing vir ’n bestaande praktiese probleem. Hierdie studie het ’n kwalitatiewe navorsingsbenadering en ’n gevallestudie-ontwerp gevolg, en was ’n verkennende studie. Hierdie studie het gebruik gemaak van onderhoude met ’n nie-statistiese kundige doelgerigte steekproeftegniek, asook document ontleding. ’n Deduktiewe benadering tot data-ontleding en interpretering is onderneem deur middel van die toepassing van die stelselsteorie en stelselsdenke-benadering as die hoofteorieë. Hulle is uitgebrei met die organisatoriese koopgedrag-en dialektiese teorieë. Aangesien die ontleding deduktief van aard was, is die die elemente van sistemiese strukture soos ontleen van die ysbergmodel toegepas vir kodering. Die studie het bevind dat Botswana se verdedigings bevoorrading totale strukturele hervorming benodig, wat insluit die behoorlike plasing van die bevoorradingsfunksie, die betrokkenheid van siviele beroepsmense, die ontwikkeling van ’n sekuriteits-en verdedigingsbeleid, asook die ontwikkeling van ’n bevoorradings model wat in lyn is met die verkryging van balans tussen verdedingsbesteding en nasionale Ontwikkelings doelwitte wat belyn is met die huidige debat rakende die Vierde Industriële Revolusie.Doctora