Sequential decision fusion of multibiometrics applied to text-dependent speaker verification for controlled errors

Reliability of the performance of biometric identity verification systems remains a significant challenge. Individual biometric samples of the same person (identity class) are not identical at each presentation and performance degradation arises from intra-class variability and inter-class similarity. These limitations lead to false accepts and false rejects that are dependent. It is therefore difficult to reduce the rate of one type of error without increasing the other. The focus of this dissertation is to investigate a method based on classifier fusion techniques to better control the trade-off between the verification errors using text-dependent speaker verification as the test platform. A sequential classifier fusion architecture that integrates multi-instance and multisample fusion schemes is proposed. This fusion method enables a controlled trade-off between false alarms and false rejects. For statistically independent classifier decisions, analytical expressions for each type of verification error are derived using base classifier performances. As this assumption may not be always valid, these expressions are modified to incorporate the correlation between statistically dependent decisions from clients and impostors. The architecture is empirically evaluated by applying the proposed architecture for text dependent speaker verification using the Hidden Markov Model based digit dependent speaker models in each stage with multiple attempts for each digit utterance. The trade-off between the verification errors is controlled using the parameters, number of decision stages (instances) and the number of attempts at each decision stage (samples), fine-tuned on evaluation/tune set. The statistical validation of the derived expressions for error estimates is evaluated on test data. The performance of the sequential method is further demonstrated to depend on the order of the combination of digits (instances) and the nature of repetitive attempts (samples). The false rejection and false acceptance rates for proposed fusion are estimated using the base classifier performances, the variance in correlation between classifier decisions and the sequence of classifiers with favourable dependence selected using the 'Sequential Error Ratio' criteria. The error rates are better estimated by incorporating user-dependent (such as speaker-dependent thresholds and speaker-specific digit combinations) and class-dependent (such as clientimpostor dependent favourable combinations and class-error based threshold estimation) information. The proposed architecture is desirable in most of the speaker verification applications such as remote authentication, telephone and internet shopping applications. The tuning of parameters - the number of instances and samples - serve both the security and user convenience requirements of speaker-specific verification. The architecture investigated here is applicable to verification using other biometric modalities such as handwriting, fingerprints and key strokes.

Information and Learning Experiences in the Cube: Vision, Implementation and Interaction

Executive Summary This project has commenced an exploration of learning and information experiences in the QUT Cube. Understanding learning in this environment has the potential to inform current implementations and future project development. In this report, we present early findings from the first phase of an investigation into what makes learning possible in the context of a giant interactive multi-media display such as the QUT Cube, which is an award-winning configuration that hosts several projects.

Mathematical models of bubble evolution in a Hele-Shaw Cell

This thesis concerns the mathematical model of moving fluid interfaces in a Hele-Shaw cell: an experimental device in which fluid flow is studied by sandwiching the fluid between two closely separated plates. Analytic and numerical methods are developed to gain new insights into interfacial stability and bubble evolution, and the influence of different boundary effects is examined. In particular, the properties of the velocity-dependent kinetic undercooling boundary condition are analysed, with regard to the selection of only discrete possible shapes of travelling fingers of fluid, the formation of corners on the interface, and the interaction of kinetic undercooling with the better known effect of surface tension. Explicit solutions to the problem of an expanding or contracting ring of fluid are also developed.

Designing for human–food interaction : an introduction to the special issue on ‘food and interaction design’

With this special issue, we draw attention to the growing and diverse field of HCI researchers exploring the interstices of food, technology and everyday practices. This special issue builds on the CHI workshop of the same name (Comber et al., 2012a), where we brought together the community of researchers that take food as a point from which to understand people and design technology. The workshop aimed to ‘to attend to the practical and theoretical difficulties in designing for human–food interactions in everyday life’ identifying four thematic areas of food practices – health and wellbeing; sustainability; food experiences; and alternative food cultures. These practical and theoretical difficulties are evident in the papers that we present here, though the distinction between our four themes, premised by complexities of food practices, is a little less evident. Thus, in the papers that follow we explore how the social, technological, cultural and methodological intertwine in the field of human–food interaction.

Development and evaluation of a program to improve clinician and patient communication during a telehealth consultation : C.R.I.S.P. Telehealth

Introduction: The delivery of health care in the 21st century will look like no other in the past. The fast paced technological advances that are being made will need to transition from the information age into clinical practice. The phenomenon of e-Health is the over-arching form of information technology and telehealth is one arm of that phenomenon. The uptake of telehealth both in Australia and overseas, has changed the face of health service delivery to many rural and remote communities for the better, removing what is known as the tyranny of distance. Many studies have evaluated the satisfaction and cost-benefit analysis of telehealth across the organisational aspects as well as the various adaptations of clinical pathways and this is the predominant focus of most studies published to date. However, whilst comments have been made by many researchers about the need to improve and attend to the communication and relationship building aspects of telehealth no studies have examined this further. The aim of this study was to identify the patient and clinician experiences, concerns, behaviours and perceptions of the telehealth interaction and develop a training tool to assist these clinicians to improve their interaction skills. Methods: A mixed methods design combining quantitative (survey analysis and data coding) and qualitative (interview analysis) approaches was adopted. This study utilised four phases to firstly qualitatively explore the needs of clients (patients) and clinicians within a telehealth consultation then designed, developed, piloted and quantitatively and qualitatively evaluated the telehealth communication training program. Qualitative data was collected and analysed during Phase 1 of this study to describe and define the missing 'communication and rapport building' aspects within telehealth. This data was then utilised to develop a self-paced communication training program that enhanced clinicians existing skills, which comprised of Phase 2 of this study to develop the interactive program. Phase 3 included evaluating the training program with 26 clinicians and results were recorded pre and post training, whilst phase 4 was the pilot for future recommendations of this training program using a patient group within a Queensland Health setting at two rural hospitals. Results: Comparisons of pre and post training data on 1) Effective communication styles, 2) Involvement in communication training package, 3) satisfaction pre and post training, and 4) health outcomes pre and post training indicated that there were differences between pre and post training in relation to effective communication style, increased satisfaction and no difference in health outcomes between pre and post training for this patient group. The post training results revealed over half of the participants (N= 17, 65%) were more responsive to non-verbal cues and were better able to reflect and respond to looks of anxiousness and confusion from a 'patient' within a telehealth consultation. It was also found that during post training evaluations, clinicians had enhanced their therapeutic communication with greater detail to their own body postures, eye contact and presentation. There was greater time spent looking at the 'patient' with an increase of 35 second intervals of direct eye contact and less time spent looking down at paperwork which decreased by 20 seconds. Overall 73% of the clinicians were satisfied with the training program and 61% strongly agreed that they recognised areas of their communication that needed improving during a telehealth consultation. For the patient group there was significant difference post training in rapport with a mean score from 42 (SD = 28, n = 27) to 48 (SD = 5.9, n = 24). For communication comfort of the patient group there was a significant difference between the pre and post training scores t(10) = 27.9, p = .002, which meant that overall the patients felt less inhibited whilst talking to the clinicians and more understood. Conclusion: The aim of this study was to explore the characteristics of good patient-clinician communication and unmet training needs for telehealth consultations. The study developed a training program that was specific for telehealth consultations and not dependent on a 'trainer' to deliver the content. In light of the existing literature this is a first of its kind and a valuable contribution to the research on this topic. It was found that the training program was effective in improving the clinician's communication style and increased the satisfaction of patient's within an e-health environment. This study has identified some historical myths that telehealth cannot be part of empathic patient centred care due to its technology tag.

Low formalin concentrations induce fine-tuned responses that are sex and age-dependent : a developmental study

The formalin test is increasingly applied as a model of inflammatory pain using high formalin concentrations (5–15%). However, little is known about the effects of low formalin concentrations on related behavioural responses. To examine this, rat pups were subjected to various concentrations of formalin at four developmental stages: 7, 13, 22, and 82 days of age. At postnatal day (PND) 7, sex differences in flinching but not licking responses were observed with 0.5% formalin evoking higher flinching in males than in females. A dose response was evident in that 0.5% formalin also produced higher licking responses compared to 0.3% or 0.4% formalin. At PND 13, a concentration of 0.8% formalin evoked a biphasic response. At PND 22, a concentration of 1.1% evoked higher flinching and licking responses during the late phase (10–30 min) in both males and females. During the early phase (0–5 min), 1.1% evoked higher licking responses compared to 0.9% or 1% formalin. 1.1% formalin produced a biphasic response that was not evident with 0.9 or 1%. At PND 82, rats displayed a biphasic pattern in response to three formalin concentrations (1.25%, 1.75% and 2.25%) with the presence of an interphase for both 1.75% and 2.25% but not for 1.25%. These data suggest that low formalin concentrations induce fine-tuned responses that are not apparent with the high formalin concentration commonly used in the formalin test. These data also show that the developing nociceptive system is very sensitive to subtle changes in formalin concentrations.

Fluid-structure interaction analysis of full scale vehicle-barrier impact using coupled SPH-FEA

Portable water-filled barriers (PWFB) are roadside structures used to separate moving traffic from work-zones. Numerical PWFB modelling is preferred in the design stages prior to actual testing. This paper aims to study the fluid-structure interaction of PWFB under vehicular impact using several methods. The strategy to treat water as non-structural mass was proposed and the errors were investigated. It was found that water can be treated with the FEA-NSM model for velocities higher than 80kmh-1. However, full SPH/FEA model is still the best treatment for water and necessary for lower impact velocities. The findings in this paper can be used as guidelines for modelling and designing PWFB.

Analysis of kinase gene expression in the frontal cortex of suicide victims: Implications of fear and stress

Suicide is a serious public health issue that results from an interaction between multiple risk factors including individual vulnerabilities to complex feelings of hopelessness, fear, and stress. Although kinase genes have been implicated in fear and stress, including the consolidation and extinction of fearful memories, expression profiles of those genes in the brain of suicide victims are less clear. Using gene expression microarray data from the Online Stanley Genomics Database 1 and a quantitative PCR, we investigated the expression profiles of multiple kinase genes including the calcium calmodulin-dependent kinase (CAMK), the cyclin-dependent kinase, the mitogen-activated protein kinase (MAPK), and the protein kinase C (PKC) in the prefrontal cortex (PFC) of mood disorder patients died with suicide (N = 45) and without suicide (N = 38). We also investigated the expression pattern of the same genes in the PFC of developing humans ranging in age from birth to 49 year (N = 46). The expression levels of CAMK2B, CDK5, MAPK9, and PRKCI were increased in the PFC of suicide victims as compared to non-suicide controls (false discovery rate, FDR-adjusted p < 0.05, fold change >1.1). Those genes also showed changes in expression pattern during the postnatal development (FDR-adjusted p < 0.05). These results suggest that multiple kinase genes undergo age-dependent changes in normal brains as well as pathological changes in suicide brains. These findings may provide an important link to protein kinases known to be important for the development of fear memory, stress associated neural plasticity, and up-regulation in the PFC of suicide victims. More research is needed to better understand the functional role of these kinase genes that may be associated with the pathophysiology of suicide

Shape dependent electrocatalytic behaviour of silver nanoparticles

The electrochemical and electrocatalytic behaviour of silver nanoprisms, nanospheres and nanocubes of comparable size in an alkaline medium have been investigated to ascertain the shape dependent behaviour of silver nanoparticles, which are an extensively studied nanomaterial. The nanomaterials were synthesised using chemical methods and characterised with UV-visible spectroscopy, transmission electron microscopy and X-ray diffraction. The nanomaterials were immobilised on a substrate glassy carbon electrode and characterised by cyclic voltammetry for their surface oxide electrochemistry. The electrocatalytic oxidation of hydrazine and formaldehyde and the reduction of hydrogen peroxide were studied by performing cyclic voltammetric and chronoamperometric experiments for both the nanomaterials and a smooth polycrystalline macrosized silver electrode. In all cases the nanomaterials showed enhanced electrocatalytic activity over the macro-silver electrode. Significantly, the silver nanoprisms that are rich in hcp lamellar defects showed greater activity than nanospheres and nanocubes for all reactions studied.

Vorinostat/SAHA-induced apoptosis in malignant mesothelioma is FLIP/caspase 8-dependent and HR23B-independent

Introduction: Malignant pleural mesothelioma (MPM) is a rapidly fatal malignancy that is increasing in incidence. The caspase 8 inhibitor FLIP is an anti-apoptotic protein over-expressed in several cancer types including MPM. The histone deacetylase (HDAC) inhibitor Vorinostat (SAHA) is currently being evaluated in relapsed mesothelioma. We examined the roles of FLIP and caspase 8 in regulating SAHA-induced apoptosis in MPM. Methods: The mechanism of SAHA-induced apoptosis was assessed in 7 MPM cell lines and in a multicellular spheroid model. SiRNA and overexpression approaches were used, and cell death was assessed by flow cytometry, Western blotting and clonogenic assays. Results: RNAi-mediated FLIP silencing resulted in caspase 8-dependent apoptosis in MPM cell line models. SAHA potently down-regulated FLIP protein expression in all 7 MPM cell lines and in a multicellular spheroid model of MPM. In 6/7 MPM cell lines, SAHA treatment resulted in significant levels of apoptosis induction. Moreover, this apoptosis was caspase 8-dependent in all six sensitive cell lines. SAHA-induced apoptosis was also inhibited by stable FLIP overexpression. In contrast, down-regulation of HR23B, a candidate predictive biomarker for HDAC inhibitors, significantly inhibited SAHA-induced apoptosis in only 1/6 SAHA-sensitive MPM cell lines. Analysis of MPM patient samples demonstrated significant inter-patient variations in FLIP and caspase 8 expressions. In addition, SAHA enhanced cisplatin-induced apoptosis in a FLIP-dependent manner. Conclusions: These results indicate that FLIP is a major target for SAHA in MPM and identifies FLIP, caspase 8 and associated signalling molecules as candidate biomarkers for SAHA in this disease. © 2011 Elsevier Ltd. All rights reserved.

Time course-dependent changes in the transcriptome of human skeletal muscle during recovery from endurance exercise: From inflammation to adaptive remodeling

Re-programming of gene expression is fundamental for skeletal muscle adaptations in response to endurance exercise. This study investigated the time-course dependent changes in the muscular transcriptome following an endurance exercise trial consisting of 1 h of intense cycling immediately followed by 1 h of intense running. Skeletal muscle samples were taken at baseline, 3 h, 48 h, and 96 h post-exercise from eight healthy, endurance-trained, male individuals. RNA was extracted from muscle. Differential gene expression was evaluated using Illumina microarrays and validated with qPCR. Gene set enrichment analysis identified enriched molecular signatures chosen from the Molecular Signatures Database. Three h post-exercise, 102 gene sets were up-regulated [family wise error rate (FWER), P < 0.05]; including groups of genes related with leukocyte migration, immune and chaperone activation, and cyclic AMP responsive element binding protein (CREB) 1-signaling. Forty-eight h post-exercise, among 19 enriched gene sets (FWER, P < 0.05), two gene sets related to actin cytoskeleton remodeling were up-regulated. Ninety-six h post-exercise, 83 gene sets were enriched (FWER, P < 0.05), 80 of which were up-regulated; including gene groups related to chemokine signaling, cell stress management, and extracellular matrix remodeling. These data provide comprehensive insights into the molecular pathways involved in acute stress, recovery, and adaptive muscular responses to endurance exercise. The novel 96 h post-exercise transcriptome indicates substantial transcriptional activity, potentially associated with the prolonged presence of leukocytes in the muscles. This suggests that muscular recovery, from a transcriptional perspective, is incomplete 96 h after endurance exercise involving muscle damage.

Shrinkage empirical likelihood estimator in longitudinal analysis with time-dependent covariates-application to modeling the health of Filipino children

The method of generalized estimating equations (GEE) is a popular tool for analysing longitudinal (panel) data. Often, the covariates collected are time-dependent in nature, for example, age, relapse status, monthly income. When using GEE to analyse longitudinal data with time-dependent covariates, crucial assumptions about the covariates are necessary for valid inferences to be drawn. When those assumptions do not hold or cannot be verified, Pepe and Anderson (1994, Communications in Statistics, Simulations and Computation 23, 939–951) advocated using an independence working correlation assumption in the GEE model as a robust approach. However, using GEE with the independence correlation assumption may lead to significant efficiency loss (Fitzmaurice, 1995, Biometrics 51, 309–317). In this article, we propose a method that extracts additional information from the estimating equations that are excluded by the independence assumption. The method always includes the estimating equations under the independence assumption and the contribution from the remaining estimating equations is weighted according to the likelihood of each equation being a consistent estimating equation and the information it carries. We apply the method to a longitudinal study of the health of a group of Filipino children.

Simulation of Au particle interaction on graphene sheets

The interaction of Au particles with few layer graphene is of interest for the formation of the next generation of sensing devices(1). In this paper we investigate the coupling of single gold nanoparticles to a graphene sheet, and multiple gold nanoparticles with a graphene sheet using COMSOL Multiphysics. By using these simulations we are able to determine the electric field strength and associated hot-spots for various gold nanoparticle-graphene systems. The Au nanoparticles were modelled as 8 nm diameter spheres on 1.5 nm thick (5 layers) graphene, with properties of graphene obtained from the refractive index data of Weber(2) and the Au refractive index data from Palik(3). The field was incident along the plane of the sheet with polarisation tested for both s and p. The study showed strong localised interaction between the Au and graphene with limited spread; however the double particle case where the graphene sheet separated two Au nanoparticles showed distinct interaction between the particles and graphene. An offset was introduced (up to 4 nm) resulting in much reduced coupling between the opposed particles as the distance apart increased. Findings currently suggest that the graphene layer has limited interaction with incident fields with a single particle present whilst reducing the coupling region to a very fine area when opposing particles are involved. It is hoped that the results of this research will provide insight into graphene-plasmon interactions and spur the development of the next generation of sensing devices.

Hyperelastic constitutive relationship for the strain-rate dependent behavior of shoulder and other joint cartilages

Non-linear finite deformations of articular cartilages under physiological loading conditions can be attributed to hyperelastic behavior. This paper contains experimental results of indentation tests in finite deformation and proposes an empirical based new generalized hyperelastic constitutive model to account for strain-rate dependency for humeral head cartilage tissues. The generalized model is based on existing hyperelastic constitutive relationships that are extensively used to represent biological tissues in biomechanical literature. The experimental results were obtained for three loading velocities, corresponding to low (1x10-3 s-1), moderate and high strain-rates (1x10-1 s-1), which represent physiological loading rates that are experienced in daily activities such as lifting, holding objects and sporting activities. Hyperelastic material parameters were identified by non linear curve fitting procedure. Analysis demonstrated that the material behavior of cartilage can be effectively decoupled into strain-rate independent(elastic) and dependent parts. Further, experiments conducted using different indenters indicated that the parameters obtained are significantly affected by the indenter size, potentially due to structural inhomogeneity of the tissue. The hyperelastic constitutive model developed in this paper opens a new avenue for the exploration of material properties of cartilage tissues.

Gene Silencing in Arabidopsis Spreads from the Root to the Shoot, through a Gating Barrier, by Template-Dependent, Nonvascular, Cell-to-Cell Movement

Upward long-distance mobile silencing has been shown to be phloem mediated in several different solanaceous species. We show that the Arabidopsis (Arabidopsis thaliana) seedling grafting system and a counterpart inducible system generate upwardly spreading long-distance silencing that travels not in the phloem but by template-dependent reiterated short-distance cell-to-cell spread through the cells of the central stele. Examining the movement of the silencing front revealed a largely unrecognized zone of tissue, below the apical meristem, that is resistant to the silencing signal and that may provide a gating or protective barrier against small RNA signals. Using a range of auxin and actin transport inhibitors revealed that, in this zone, alteration of vesicular transport together with cytoskeleton dynamics prevented or retarded the spread of the silencing signal. This suggests that small RNAs are transported from cell to cell via plasmodesmata rather than diffusing from their source in the phloem.