Graduate Co-op Program - administration grant

Issued as Performance report, Project no. A-54-811 (continuation of A-54-810

Android Based Behavioral Biometric Authentication via Multi-Modal Fusion

Because mobile devices are easily lost or stolen, continuous authentication is extremely desirable for them. Behavioral biometrics provides non-intrusive continuous authentication that has much less impact on usability than active authentication. However single-modality behavioral biometrics has proven less accurate than standard active authentication. This thesis presents a behavioral biometric system that uses multi-modal fusion with user data from touch, keyboard, and orientation sensors. Testing of ve users shows that fusion of modalities provides more accurate authentication than each individual modalities by itself. Using the BayesNet classification algorithm, fusion achieves False Acceptance Rate (FAR) and False Rejection Rate (FRR) values of 9.65% and 2% respectively, each of which is 8% lower than the closest individual modality

Dynamical system analysis of ignition phenomena using the tangential stretching rate concept

We analyze ignition phenomena by resorting to the stretching rate concept formerly introduced in the study of dynamical systems. We construct a Tangential Stretching Rate (TSR) parameter by combining the concepts of stretching rate with the decomposition of the local tangent space in eigen-modes. The main feature of the TSR is its ability to identify unambiguously the most energetic scale at a given space location and time instant. The TSR depends only on the local composition of the mixture, its temperature and pressure. As such, it can be readily computed during the post processing of computed reactive flow fields, both for spatially homogeneous and in-homogenous systems. Because of the additive nature of the TSR, we defined a normalized participation index measuring the relative contribution of each mode to the TSR. This participation index to the TSR can be combined with the mode amplitude participation Index of a reaction to a mode – as defined in the Computational Singular Perturbation (CSP) method – to obtain a direct link between a reaction and TSR. The reactions having both a large participation index to the TSR and a large CSP mode amplitude participation index are those contributing the most to both the explosive and relaxation regimes of a reactive system. This information can be used for both diagnostics and for the simplification of kinetic mechanisms. We verified the properties of the TSR with reference to three nonlinear planar models (one for isothermal branched-chain reactions, one for a non-isothermal, one-step system, and for non-isothermal branched-chain reactions), to one planar linear model (to discuss issues associated with non-normality), and to test problems involving hydro-carbon oxidation kinetics. We demonstrated that the reciprocal of the TSR parameter is the proper characteristic chemical time scale in problems involving multi-step chemical kinetic mechanisms, because (i) it is the most relevant time scale during both the explosive and relaxation regimes and (ii) it is intrinsic to the kinetics, that is, it can be identified without the need of any ad hoc assumption

Microperimetric evaluation in patients with adult-onset foveomacular vitelliform dystrophy

INTRODUCTION: To compare mean best-corrected visual acuity (BCVA), retinal sensitivity (RS), and bivariate contour ellipse area (BCEA) in patients with adult-onset foveomacular vitelliform dystrophy (AOFVD) and healthy subjects (HSs), reporting also functional disease-related changes in the different stages of the AOFVD disease. MATERIALS AND METHODS: In this observational cross-sectional study, a total of 19 patients (30 eyes; 12 female and 7 male) with AOFVD were enrolled, and 30 patients (30 eyes; 16 female and 14 male) were recruited as age-matched control group (74.36 ± 9.17 years vs. 71.83 ± 6.99 years respectively, P= 0.11). All patients underwent a complete ophthalmologic examination, fundus autofluorescence and fluorescein angiography, spectral-domain optical coherence tomography and microperimetry (MP)-1 analysis. The data collection included mean BCVA, mean RS measured by means of MP-1, BCEA, and central retinal thickness. RESULTS: All the functional parameters (BCVA, RS, and BCEA) were significantly worse in AOFVD group than HS. Subgroup analysis showed that the most significant functional changes, quantified by mean BCVA, RS, and BCEA, were in the atrophic stage (P = 0.03, P= 0.01, and P= 0.001, respectively). All the functional parameters were well correlated in the different stages. CONCLUSIONS: This study further confirms the good visual prognosis in the AOFVD eyes. Fixation stability measurement using BCEA demonstrates good evaluation of visual performance integrating traditional functional parameters. It may also serve for further rehabilitative purposes in atrophic eyes

Periodontal evaluation of palatally impacted maxillary canines treated by closed approach with ultrasonic surgery and orthodontic treatment: a retrospective pilot study

Aim of this study is the evaluation of the periodontal status of impacted canines treated by closed approach with ultrasonic surgery and orthodontic treatment compared with contralateral spontaneously erupted teeth. The periodontal conditions of the teeth adjacent to the canines (lateral incisors and first premolar) were also considered. 17 patients (9 females and 8 males; mean age: 15.2 years) with unilateral palatal impaction of maxillary canine were selected. All patients were treated by closed-flap surgery with ultrasonic instruments. Periodontal status was evaluated by assessing probing depth (PD), gingival recession and width of keratinized tissue (KT) 4.6 months after the end of the orthodontic treatment, on average. Test group was composed by impacted elements and adjacent teeth and control group by contralateral spontaneously erupted canines and adjacent teeth. Student's t-test was used to compare test and control group values of PD and width of KT. Significance threshold for Student's t-test was set at p < 0.05. The average probing depth values show no significant clinical differences between the test and control groups. Probing depths recorded at the mesiovestibular and distopalatal sides of the impacted canine were statistically significant compared to the control elements (p < 0.05). No gingival recession was detected on the treated canines. The measurement of KT did not differ significantly between the test and the control groups. In conclusion, the ultrasonic surgery for disinclusion associated with a closed approach and orthodontic traction allows the alignment of an impacted palatal canine without damaging the periodontium

Fourier-Domain Optical Coherence Tomography and Microperimetry Findings in Retinitis Pigmentosa

PURPOSE: To investigate the relation between the optical coherence tomography (OCT) findings and retinal sensitivity in patients with retinitis pigmentosa (RP) by assessing the retinal thickness and retinal function using Fourier-domain OCT (FD-OCT) and microperimetry, respectively. DESIGN: Observational case series. METHODS: Fifty-nine patients (118 eyes) were enrolled, mean age 47 +/- 14.8 years. Thirty-two healthy subjects (HS) were enrolled as a control group. Patients were assessed by means of FD-OCT and microperimetry. We analyzed the average foveal thickness (diameter of 1 mm centered on the point of fixation), the value of the retinal sensitivities corresponding to the 4 degrees centered on the fixation point, and logMAR visual acuity for regression analysis converted from Snellen chart. RESULTS: We distinguished 4 groups of RP patients according to the macular pattern seen on OCT images. The first group of 36 eyes, mean age of 33.5 +/- 7.4 years, had no macular changes, mean best-corrected visual acuity (BCVA) of 0.95 +/- 0.07, mean foveal thickness of 256.3 +/- 9.14 mu m, and mean retinal sensitivities inside the central 4 degrees of 19.27 +/- 0.87 dB (P > .05 for all the values). The second group of 28 eyes, mean age 35.4 +/- 6.3 years, showed clinical macular edema (CME) on OCT images with mean BCVA of 0.72 +/- 0.22, mean foveal thickness of 363.5 +/- 93.45 mu m, and mean retinal sensitivity inside the central 4 degrees of 15.94 +/- 3.6 dB (P < .01 for all the values). The third group of 26 eyes, mean age 50.8 +/- 8.7 years, showed macular vitreoretinal traction on OCT images with a mean BCVA of 0.5 +/- 0.2, mean foveal thickness of 337.1 +/- 71.7 mu m, and mean retinal sensitivity inside the central 4 degrees of 11.78 +/- 3.09 dB (P < .01 for all the values). The last group of 28 eyes, mean age 52.1 +/- 13.6 years, showed macular retinal thinning on OCT images with mean BCVA of 0.36 +/- 0.15, mean foveal thickness of 174.2 +/- 24.40 mu m, and mean retinal sensitivity inside the central 4 degrees of 10.22 +/- 3.82 dB (P < .01 for all the values). CONCLUSIONS: MP-1 and FD-OCT showed high sensitivity for identifying functional and structural macular abnormalities, respectively. Future studies should investigate the relationships among photoreceptor cell loss, retinal sensitivity, and fixation in patients with RP. (Am J Ophthalmol 2011;151:106-111. (C) 2011 by Elsevier Inc. All rights reserved.

Condylar reshaping in a TMD patient after ortho-prosthetic treatment : a 20-year follow-up case report

Temporomandibular disorders (TMDs) involve different conditions with similar symptoms and signs affecting the temporomandibular joints (TMJs), the muscles of mastication, or both. The symptoms and signs of TMDs are several: pain and tenderness in and aro

Investigation of the generalization capability of a generative adversarial network for large eddy simulation of turbulent premixed reacting flows

In the past decades, Deep Learning (DL) frameworks have demonstrated excellent performance in modeling nonlinear interactions and are a promising technique to move beyond physics-based models. In this context, super-resolution techniques may present an accurate approach as subfilter-scale (SFS) closure model for Large Eddy Simulations (LES) in premixed combustion. However, DL models need to perform accurately in a variety of physical regimes and generalize well beyond their training conditions. In this work, a super-resolution Generative Adversarial Network (GAN) is proposed as closure model for the unresolved subfilter-stress and scalar-flux tensors of the filtered reactive Navier-Stokes equations solved in LES. The model trained on a premixed methane/air jet flame is evaluated a-priori on similar configurations at different Reynolds and Karlovitz numbers. The GAN generalizes well at both lower and higher Reynolds numbers and outperforms existing algebraic models when the ratio between the filter size and the Kolmogorov scale is preserved. Moreover, extrapolation at a higher Karlovitz number is investigated indicating that the ratio between the filter size and the thermal flame thickness may not need to be conserved in order to achieve high correlation in terms of SFS field. Generalization studies obtained on substantially different flame conditions indicate that successful predictive abilities are demonstrated if the generalization criterion is matched. Finally, the reconstruction of a scalar quantity, different from that used during the training, is evaluated, revealing that the model is able to reconstruct scalar fields with large gradients that have not been explicitly used in the training. The a-priori investigations carried out assess whether out-of-sample predictions are even feasible in the first place, providing insights into the quantities that need to be conserved for the model to perform well between different regimes, and represent a crucial step toward future embedding into LES numerical solvers

Can computer-guided surgery help orthodontics in miniscrew insertion and corticotomies? A narrative review

Orthodontics has considerably increased the use of technology combined with surgery as a tool to improve dental movements in terms of predictability, acceleration of movement, and fewer side effects. To achieve these goals miniscrews and corticotomy were introduced. The digital workflow permits an increase in the accuracy of surgical and orthodontic setups. The tool that transfers the information is the CAD/CAM (Computer-Aided Design/ Computer-Aided Manufacturing) template. The aim of this review is to illustrate the use of computer-guided surgery in orthodontics regarding miniscrews and piezocision. The search strategy was a combination of Medical Subject Headings (Mesh) and free text words for PubMed. A total of 27 articles were included in this review: 16 concerned miniscrews and 11 concerned corticotomy. The current need for faster treatments, the improved systems of anchorage, and the evolution of imaging technologies require operators to be knowledgeable of the digital workflow. CAD/CAM templates allow greater precision and predictability of miniscrew insertion even if in the hands of less experienced clinicians and permit a better orientation and depth of the cortical incision. In conclusion, digital planning makes surgery faster and easier and allows for the identification and correction of any potential problem before the procedure

Psychosis, Mood and Behavioral Disorders in Usher Syndrome: Review of the Literature

The aim of this review is to focus the current knowledge about mental and behavioral disorders in Usher syndrome. Previous studies described the presence of various mental disorders associated with Usher syndrome, suggesting possible mechanisms of association between these disorders. The most common manifestations are schizophrenia-like disorder and psychotic symptoms. Mood and behavioral disorders are rarely described, and often are associated with more complex cases in co-occurrence with other psychiatric disorders. Neuroimaging studies reported diffuse involvement of central nervous system (CNS) in Usher patients, suggesting a possible role of CNS damage in the pathogenesis of psychiatric manifestations. Genetic hypothesis and stress-related theories have also been proposed