Investigation of the impact of high frequency transmitted speech on speaker recognition

Thesis (MScEng)--Stellenbosch University, 2002.Some digitised pages may appear illegible due to the condition of the original hard copy.ENGLISH ABSTRACT: Speaker recognition systems have evolved to a point where near perfect performance can be obtained under ideal conditions, even if the system must distinguish between a large number of speakers. Under adverse conditions, such as when high noise levels are present or when the transmission channel deforms the speech, the performance is often less than satisfying. This project investigated the performance of a popular speaker recognition system, that use Gaussian mixture models, on speech transmitted over a high frequency channel. Initial experiments demonstrated very unsatisfactory results for the base line system. We investigated a number of robust techniques. We implemented and applied some of them in an attempt to improve the performance of the speaker recognition systems. The techniques we tested showed only slight improvements. We also investigates the effects of a high frequency channel and single sideband modulation on the speech features of speech processing systems. The effects that can deform the features, and therefore reduce the performance of speech systems, were identified. One of the effects that can greatly affect the performance of a speech processing system is noise. We investigated some speech enhancement techniques and as a result we developed a new statistical based speech enhancement technique that employs hidden Markov models to represent the clean speech process.AFRIKAANSE OPSOMMING: Sprekerherkenning-stelsels het 'n punt bereik waar nabyaan perfekte resultate verwag kan word onder ideale kondisies, selfs al moet die stelsel tussen 'n groot aantal sprekers onderskei. Wanneer nie-ideale kondisies, soos byvoorbeeld hoë ruisvlakke of 'n transmissie kanaal wat die spraak vervorm, teenwoordig is, is die resultate gewoonlik nie bevredigend nie. Die projek ondersoek die werksverrigting van 'n gewilde sprekerherkenning-stelsel, wat gebruik maak van Gaussiese mengselmodelle, op spraak wat oor 'n hoë frekwensie transmissie kanaal gestuur is. Aanvanklike eksperimente wat gebruik maak van 'n basiese stelsel het nie goeie resultate opgelewer nie. Ons het 'n aantal robuuste tegnieke ondersoek en 'n paar van hulle geïmplementeer en getoets in 'n poging om die resultate van die sprekerherkenning-stelsel te verbeter. Die tegnieke wat ons getoets het, het net geringe verbetering getoon. Die studie het ook die effekte wat die hoë-frekwensie kanaal en enkel-syband modulasie op spraak kenmerkvektore, ondersoek. Die effekte wat die spraak kenmerkvektore kan vervorm en dus die werkverrigting van spraak stelsels kan verlaag, is geïdentifiseer. Een van die effekte wat 'n groot invloed op die werkverrigting van spraakstelsels het, is ruis. Ons het spraak verbeterings metodes ondersoek en dit het gelei tot die ontwikkeling van 'n statisties gebaseerde spraak verbeteringstegniek wat gebruik maak van verskuilde Markov modelle om die skoon spraakproses voor te stel

Treatment based classification systems for patients with non-specific neck pain:A systematic review

Objective: We aimed to identify published classification systems with a targeted treatment approach (treatment-based classification systems (TBCSs)) for patients with non-specific neck pain, and assess their quality and effectiveness. Design: Systematic review. Data sources: MEDLINE, CINAHL, EMBASE, PEDro and the grey literature were systematically searched from inception to December 2019. Study appraisal and synthesis: The main selection criterium was a TBCS for patients with non-specific neck pain with physiotherapeutic interventions. For data extraction of descriptive data and quality assessment we used the framework developed by Buchbinder et al. We considered as score of ≤3 as low quality, a score between 3 and 5 as moderate quality and a score ≥5 as good quality. To assess the risk of bias of studies concerning the effectiveness of TBCSs (only randomized clinical trials (RCTs) were included) we used the PEDro scale. We considered a score of ≥ six points on this scale as low risk of bias. Results: Out of 7664 initial references we included 13 studies. The overall quality of the TBCSs ranged from low to moderate. We found two RCTs, both with low risk of bias, evaluating the effectiveness of two TBCSs compared to alternative treatments. The results showed that both TBCSs were not superior to alternative treatments. Conclusion: Existing TBCSs are, at best, of moderate quality. In addition, TBCSs were not shown to be more effective than alternatives. Therefore using these TBCSs in daily practice is not recommended

Completeness of the description of manipulation and mobilisation techniques in randomized controlled trials in neck pain:A review using the TiDieR checklist

Study design: A secondary analysis of a systematic review. Background: Manipulations or mobilizations are commonly used interventions in patients with mechanical neck pain. The treatment effects have often been studied in randomized controlled trials (RCT) which are generally considered the gold standard in evaluating the treatment effects, mainly due to its high internal validity. External validity is defined as the extent to which the effects can be generalised to clinical practice. An important prerequisite for this is that interventions used in clinical trials can be replicated in clinical practice. It can be questioned if interventions utilized in randomized controlled trials can be translated into clinical practice. Objectives: The overall aim of this study is to examine whether the quality of the description of manipulation and mobilization interventions is sufficient for to replication of these interventions in clinical practice. Methods: A comprehensive literature search was performed. Two independent researchers used the Template for Intervention Description and Replication (TIDieR) which is a 12-item checklist for describing the completeness of the interventions. Results: Sixty-seven articles were included that used manipulation and/or mobilization interventions for patients with mechanical neck pain. None of the articles describe the intervention e.g. all the items on the TIDieR list. Considering item 8 (a-f) of the TIDieR checklist only one article described the used techniques completely. Conclusion: Manipulation or a mobilization interventions are poorly reported in RCTs, which jeopardize the external validity of RCTs, making it difficult for clinicians and researchers to replicate these interventions

Toll-Like Receptor Gene Expression in Cecum and Spleen of Chicks Challenged with Salmonella Enterica Serovar Enteritidis

Toll-like receptors (TLR) recognize pathogenassociated molecular patterns (PAMP) of infectious microbes. Activation of TLR with PAMP can result in immune response by modulation of innate and adoptive immune system. This study aimed to investigate the acute effect of Salmonella challenge on TLR RNA expression in cecum and spleen of birds from different genetic lines. Chicks from broiler, Leghorn, and Fayoumi lines were challenged or mock challenged with Salmonella. The RNA expression levels of TLR2, TLR4 and TLR5 genes were assessed by quantitative RT-PCR in cecum and spleen tissue harvested at 2 or 18 h post-challenge. The results demonstrate a significant genetic line effect on TLR expression in the spleen of Salmonella infected birds, which may partly explain the genetic variability in immune response to Salmonella enterica serovar Enteritidis. The higher level of TLR2 and TLR4 RNA expression observed in the spleen of Fayoumi line compare to Leghorn and broiler lines in Salmonella enterica serovar Enteritidis challenged birds may be associated with the stronger immune response to the infection and might be useful characteristics to be considered in breeding immunocompetent chickens

The sacroiliac part of the iliolumbar ligament

The iliolumbar ligament has been described as the most important ligament for restraining movement at the lumbosacral junction. In addition, it may play an important role in restraining movement in the sacroiliac joints. To help understand its presumed restraining effect, the anatomy of the ligament and its orientation with respect to the sacroiliac joints were studied in 17 cadavers. Specific dissection showed the existence of several distinct parts of the iliolumbar ligament, among which is a sacroiliac part. This sacroiliac part originates on the sacrum and blends with the interosseous sacroiliac ligaments. Together with the ventral part of the iliolumbar ligament it inserts on the medial part of the iliac crest, separate from the interosseous sacroiliac ligaments. Its existence is verified by magnetic resonance imaging and by cryosectioning of the pelvis in the coronal and transverse plane. Fibre direction, length, width, thickness and orientation of the sacroiliac part of the iliolumbar ligament are described. It is mainly oriented in the coronal plane, perpendicular to the sacroiliac joint. The existence of this sacroiliac part of the iliolumbar ligament supports the assumption that the iliolumbar ligament has a direct restraining effect on movement in the sacroiliac joints

Spinal manipulation and mobilisation in the treatment of infants, children, and adolescents: a systematic scoping review

PURPOSE: To i) identify and map the available evidence regarding effectiveness and harms of spinal manipulation and mobilisation for infants, children and adolescents with a broad range of conditions; ii) identify and synthesise policies, regulations, position statements and practice guidelines informing their clinical use. DESIGN: Systematic scoping review, utilising four electronic databases (PubMed, Embase, CINHAL and Cochrane) and grey literature from root to 4(th) February 2021. PARTICIPANTS: Infants, children and adolescents (birth to < 18 years) with any childhood disorder/condition. INTERVENTION: Spinal manipulation and mobilisation OUTCOME MEASURES: Outcomes relating to common childhood conditions were explored. METHOD: Two reviewers (A.P., L.L.) independently screened and selected studies, extracted key findings and assessed methodological quality of included papers using Joanna Briggs Institute Checklist for Systematic Reviews and Research Synthesis, Joanna Briggs Institute Critical Appraisal Checklist for Text and Opinion Papers, Mixed Methods Appraisal Tool and International Centre for Allied Health Evidence Guideline Quality Checklist. A descriptive synthesis of reported findings was undertaken using a levels of evidence approach. RESULTS: Eighty-seven articles were included. Methodological quality of articles varied. Spinal manipulation and mobilisation are being utilised clinically by a variety of health professionals to manage paediatric populations with adolescent idiopathic scoliosis (AIS), asthma, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), back/neck pain, breastfeeding difficulties, cerebral palsy (CP), dysfunctional voiding, excessive crying, headaches, infantile colic, kinetic imbalances due to suboccipital strain (KISS), nocturnal enuresis, otitis media, torticollis and plagiocephaly. The descriptive synthesis revealed: no evidence to explicitly support the effectiveness of spinal manipulation or mobilisation for any condition in paediatric populations. Mild transient symptoms were commonly described in randomised controlled trials and on occasion, moderate-to-severe adverse events were reported in systematic reviews of randomised controlled trials and other lower quality studies. There was strong to very strong evidence for ‘no significant effect’ of spinal manipulation for managing asthma (pulmonary function), headache and nocturnal enuresis, and inconclusive or insufficient evidence for all other conditions explored. There is insufficient evidence to draw conclusions regarding spinal mobilisation to treat paediatric populations with any condition. CONCLUSION: Whilst some individual high-quality studies demonstrate positive results for some conditions, our descriptive synthesis of the collective findings does not provide support for spinal manipulation or mobilisation in paediatric populations for any condition. Increased reporting of adverse events is required to determine true risks. Randomised controlled trials examining effectiveness of spinal manipulation and mobilisation in paediatric populations are warranted. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03781-6

Retrospective data analysis of all requests for flow cytometric immunophenotyping in a tertiary hospital setting

Flow cytometry is a globally accepted diagnostic tool used for the rapid identification of cells based on their surface and intracellular antigens, especially for the diagnosis of haematological malignancies. The aim of this study was to evaluate the requests received for flow cytometric immunophenotyping and to create a profile of diagnoses. In 2014 data regarding indications and diagnoses were captured from request forms received and final diagnosis reports issued by the Tshwane Academic Division (TAD) of the National Health Laboratory Service (NHLS). A total of 1234 requests were received over the one year period, of which 80.4% were performed and 16.8 % were rejected. The most common indications were leukaemia, lymphoma and cytopenia. Nineteen percent of requests received contained no correct indication or clinical history. In total, 103 and 153 diagnoses were established based on peripheral blood and bone marrow aspirate specimens respectively. Samples were mostly rejected due to sample clotting, electronic gate keeping rules and receiving the specimen more than 24 hours after collection.http://www.smltsa.org.za/publications.htmlam2018Haematolog

Implementation processes in a cognitive rehabilitation intervention for people with dementia: a complexity-informed qualitative analysis

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ. https://creativecommons.org/licenses/by/4.0/Objectives: Healthcare is often delivered through complex interventions. Understanding how to implement these successfully is important for optimising services. This article demonstrates how the complexity theory concept of ‘self-organisation’ can inform implementation, drawing on a process evaluation within a randomised controlled trial of the GREAT (Goal-oriented cognitive Rehabilitation in Early-stage Alzheimer’s and related dementias: a multi-centre single-blind randomised controlled Trial) intervention which compared a cognitive rehabilitation intervention for people with dementia with usual treatment. Design: A process evaluation examined experiences of GREAT therapists and participants receiving the intervention, through thematic analysis of a focus group with therapists and interviews with participants and their carers. Therapy records of participants receiving the intervention were also analysed using adapted framework analysis. Analysis adopted a critical realist perspective and a deductive-inductive approach to identify patterns in how the intervention operated. Setting: The GREAT intervention was delivered through home visits by therapists, in eight regions in the UK. Participants: Six therapists took part in a focus group, interviews were conducted with 25 participants and 26 carers, and therapy logs for 50 participants were analysed. Intervention: A 16-week cognitive rehabilitation programme for people with mild-to-moderate dementia. Results: ‘Self-organisation’ of the intervention occurred through adaptations made by therapists. Adaptations included simplifying the intervention for people with greater cognitive impairment, and extending it to meet additional needs. Relational work by therapists produced an emergent outcome of ‘social support’. Self-organised aspects of the intervention were less visible than formal components, but were important aspects of how it operated during the trial. This understanding can help to inform future implementation. Conclusions: Researchers are increasingly adopting complexity theory to understand interventions. This study extends the application of complexity theory by demonstrating how ‘self-organisation’ was a useful concept for understanding aspects of the intervention that would have been missed by focusing on formal intervention components. Analysis of self-organisation could enhance future process evaluations and implementation studies. Trial registration number: ISRCTN21027481.Peer reviewedFinal Published versio

Participants' unspoken thoughts and feelings negatively influence the therapeutic alliance; a qualitative study in a multidisciplinary pain rehabilitation setting

PURPOSE: This study aimed to explore factors that influence participants' perceptions of the therapeutic alliance with healthcare professionals; their participation in the alliance; and their commitment to treatment in a multidisciplinary pain rehabilitation setting. MATERIALS AND METHODS: A qualitative research-design was used and 26 participants in a multidisciplinary pain rehabilitation program were interviewed in-depth. RESULTS: Initially, participants reported to be satisfied with their healthcare professionals. After deeper reflection on the therapeutic alliance, several unspoken thoughts and feelings and relational ruptures emerged. Almost all participants mentioned a history of disappointing and fragmented healthcare, and they reported on how this affected their cognitions, perceptions, and beliefs about the current program. Participants felt insufficiently empowered to voice their concerns and regularly chose to avoid confrontation by not discussing their feelings. They felt a lack of ownership of their problems and did not experience the program as person-centered. CONCLUSIONS: Several factors were found that negatively influence the quality of therapeutic alliance (agreement on bond) and efficacy of the treatment plan (agreement on goals and tasks). To improve outcomes of pain rehabilitation, healthcare professionals should systematically take into account the perceptions and needs of participants, and focus more on personalized collaboration throughout the program offered.Implications for rehabilitationDifferences in perceptions and experiences of pain, together with differences in beliefs about the causes of pain, negatively influence the therapeutic alliance.When participants and healthcare professionals operate from different paradigms, it is important that they negotiate these differences.From the perspective of participants, a clear-cut organization of healthcare that encourages collaboration is required.It is important to focus on personalized collaboration from the start and during treatment, and to recognize and discuss disagreement on diagnosis and treatment plans.During this collaboration, healthcare professionals should systematically take into account the perceptions and needs of the participants

The Working Alliance Inventory's Measurement Properties:A Systematic Review

Measurement properties of the Working Alliance Inventory (WAI) and its various translations and adaptations for specific target groups have been investigated for over 30 years. No systematic review analyzing studies on measurement properties of the WAI has been conducted to date. COnsensus-based Standards for the selection of health Measurements INstruments (COSMIN) were developed for conducting high-quality systematic reviews on measurement properties in a transparent and standardized way. Aim of this study was to systematically review studies on measurement properties of the WAI, and its adapted versions, within psychotherapy, and other healthcare contexts using COSMIN criteria. PsycINFO, Medline, and EMBASE were searched (1989-2021). In all phases of the review procedure, study selection, data extraction, risk of bias assessment, rating of the quality of measurement properties, and rating of the quality of evidence for measurement properties, disagreement between reviewers was resolved by discussion. Results on validity, internal structure, reliability, construct validity, and responsiveness were analyzed. In total 66 studies were included. In most studies, evidence for measurement properties was according to COSMIN criteria, insufficient, lacking, or conflicting. Content validity was rated insufficient because neither patients nor healthcare professionals were involved in the development and validation process. Hence evidence for content validity of the WAI is unknown. Conflicting evidence was found for structural validity. Evidence for internal consistency could not be established. Limited evidence was found for inter-rater reliability and convergent validity. Conflicting evidence was also found for test-retest reliability and divergent validity. COSMIN criteria exposed persistent problems in validation studies of the WAI. These findings may indicate that measurement properties of the WAI are not up to current standards, or that COSMIN criteria may be less appropriate for assessing measurement properties of the WAI, or it could indicate both. The results of this systematic review suggest that WAI outcomes should be interpreted with caution and further research is needed regarding the content validity and hypotheses development. For the future, the theoretical framework underlying the measurement of the working alliance needs to be studied in psychotherapy and other health contexts, and tested in methodologically sound studies