Direct data-driven filter design for automotive controlled suspensions

This paper investigates the filter design problem for automotive controlled suspensions when no mathematical model of the system is available, but a set of initial experiments can be performed, where also the variable to be estimated is measured. The problem of designing suitable linear time-invariant filters is here investigated, focusing the attention on the estimation of the relative vertical speed between chassis and wheel, using the data provided by two accelerometers measuring the chassis and wheel accelerations. Disturbances and noises are supposed to be norm-bounded and optimality refers to the minimization of the induced norm from disturbances to the estimation error. A Set Membership formulation is followed and, for classes of filters with exponentially decaying impulse response, an approximating set is determined guaranteed to contain all the solutions to the optimal filtering problem. A method is proposed for designing almost-optimal filters with finite impulse response, whose worst-case estimation error is at most twice the lowest achievable one. Numerical simulations using standard "benchmark" road profiles illustrate the effectiveness of the proposed solutions

Direct data-driven filter design for automotive controlled suspensions

This paper investigates the filter design problem for automotive controlled suspensions when no mathematical model of the system is available, but a set of initial experiments can be performed, where also the variable to be estimated is measured. The problem of designing suitable linear time-invariant filters is here investigated, focusing the attention on the estimation of the relative vertical speed between chassis and wheel, using the data provided by two accelerometers measuring the chassis and wheel accelerations. Disturbances and noises are supposed to be norm-bounded and optimality refers to the minimization of the induced norm from disturbances to the estimation error. A Set Membership formulation is followed and, for classes of filters with exponentially decaying impulse response, an approximating set is determined guaranteed to contain all the solutions to the optimal filtering problem. A method is proposed for designing almost-optimal filters with finite impulse response, whose worst-case estimation error is at most twice the lowest achievable one. Numerical simulations using standard "benchmark" road profiles illustrate the effectiveness of the proposed solutions

Data-driven inversion-based control of nonlinear systems

In this paper, we introduce the Data-Driven Inversion-Based Control (D2-IBC) method for nonlinear control system design. The method relies on a two degree-of-freedom architecture, with a nonlinear controller and a linear controller running in parallel, and does not require any detailed physical knowledge of the plant to control. Specically, we use input/output data to synthesize the control action by employing convex optimization tools only. We show the eectiveness of the proposed approach on a simulation example, where the D2-IBC performance is also compared to that of the Direct FeedbacK (DFK) design approach, a benchmark method for nonlinear controller design from data

A data-driven approach to nonlinear braking control

In modern road vehicles, active braking control systems are crucial elements to ensure safety and lateral stability. Unfortunately, the wheel slip dynamics is highly nonlinear and the on-line estimation of the road-tire conditions is still a challenging open research problem. These facts make it difficult to devise a braking control system that is reliable in any situation without being too conservative. In this paper, we propose the Data-Driven Inversion Based Control (D2-IBC) approach to overcome the above issues. The method relies on a two degrees of freedom architecture, with a linear controller and a nonlinear controller in parallel, both designed using only experimental data. The effectiveness of the proposed approach is shown by means of an extensive simulation campaign

A study of the effects of the cathode configuration on the plasma kinetics and neutron emission of plasma-focus discharges in deuterium

The differences in performance of a 1.9 kJ plasma-focus device PACO assembled with three different cathode configurations are experimentally qualified. In particular, the current sheath kinetics and the neutron yield operating with deuterium gas are systematically studied for the whole range of neutron-producing pressures, and the measurements are analyzed searching for relations between relevant physical magnitudes. The pinching time was found correlated with the dimensionless driver parameter, and this feature was found statistically independent of the cathode. The variation of the inductance jump associated with the radial collapse stage is used to estimate the effective pinch length, (7.3 ± 1.6) mm, and radius, (3.6 ± 2.1 ) mm. The maximum production in a single shot was registered for the smallest cathode radius, 41 mm, whereas the intermediate cathode radius, 45 mm, scored better in average. In all configurations, the neutrons per deuteron pair correlates fairly well with an estimation of the effective equilibrium temperature of the pinch, which suggests a prevalence of thermonuclear neutrons measured perpendicularly to the focus axis.Fil: Barbaglia, Mario Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giovachini, Ricardo Hernán. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Milanese, Maria Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Clausse, Alejandro. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Interstitial lung abnormalities: new insights between theory and clinical practice

: Interstitial lung abnormalities (ILAs) represent radiologic abnormalities incidentally detected on chest computed tomography (CT) examination, potentially related to interstitial lung diseases (ILD). Numerous studies have demonstrated that ILAs are associated with increased risk of progression toward pulmonary fibrosis and mortality. Some radiological patterns have been proven to be at a higher risk of progression. In this setting, the role of radiologists in reporting these interstitial abnormalities is critical. This review aims to discuss the most recent advancements in understanding this radiological entity and the open issues that still prevent the translation from theory to practice, emphasizing the importance of ILA recognition and adequately reporting in clinical practice

The diagnostic value of grey-scale inversion technique in chest radiography

Purpose: We investigated whether the additional use of grey-scale inversion technique improves the interpretation of eight chest abnormalities, in terms of diagnostic performance and interobserver variability. Material and methods: A total of 507 patients who underwent a chest computed tomography (CT) examination and a chest radiography (CXR) within 24 h were enrolled. CT was the standard of reference. Images were retrospectively reviewed for the presence of atelectasis, consolidation, interstitial abnormality, nodule, mass, pleural effusion, pneumothorax and rib fractures. Four CXR reading settings, involving 3 readers were organized: only standard; only inverted; standard followed by inverted; and inverted followed by standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy, assessed with the area under the curve (AUC), and their 95% confidence interval were calculated for each reader and setting. Interobserver agreement was tested by Cohen's K test with quadratic weights (Kw) and its 95%CI. Results: CXR sensitivity % for any finding was 35.1 (95% CI: 33 to 37) for setting 1, 35.9 (95% CI: 33 to 37), for setting 2, 32.59 (95% CI: 30 to 34) for setting 3, and 35.56 (95% CI: 33 to 37) for setting 4; specificity % 93.78 (95% CI: 91 to 95), 93.92 (95% CI: 91 to 95), 94.43 (95% CI: 92 to 96), 93.86 (95% CI: 91 to 95); PPV % 56.22 (95% CI: 54.2 to 58.2), 56.49 (95% CI: 54.5 to 58.5), 57.15 (95% CI: 55 to 59), 56.75 (95% CI: 54 to 58); NPV % 85.66 (95% CI: 83 to 87), 85.74 (95% CI: 83 to 87), 85.29 (95% CI: 83 to 87), 85.73 (95% CI: 83 to 87); AUC values 0.64 (95% CI: 0.62 to 0.66), 0.65 (95% CI: 0.63 to 0.67), 0.64 (95% CI: 0.62 to 0.66), 0.65 (95% CI: 0.63 to 0.67); Kw values 0.42 (95% CI: 0.4 to 0.44), 0.40 (95% CI: 0.38 to 0.42), 0.42 (95% CI: 0.4 to 0.44), 0.41 (95% CI: 0.39 to 0.43) for settings 1, 2, 3 and 4, respectively. Conclusions: No significant advantages were observed in the use of grey-scale inversion technique neither over standard display mode nor in combination at the detection of eight chest abnormalities

Neutrophil-to-lymphocyte ratio may be associated with the outcome in patients with prostate cancer

Purpose: Evidences have shown that neutrophil-to-lymphocyte ratio (NLR) has a prognostic value in patients with cancer. We wanted to test the prognostic significance of NLR in prostatic cancer of patients who are candidate to radical prostatectomy. Methods: We have considered 731 patients. Complete demographic data including age, tumor stage, Gleason score, complete blood count and serum biochemical profile were collected. Pre-treatment percentage of neutrophils and NLR were considered, and correlated with patients data and recurrence free survival. Results: 389 patients were evaluated, mean age 65 years, mean follow-up 51.5 months, mean recurrence free survival 51.3 months. Total neutrophil count does not correlate with biochemical recurrence and disease free survival. Patients with a value higher of 60% of neutrophils are more likely to have a recurrence. Patients with a total lymphocyte count <1,500 have a higher rate of relapse. NLR was not correlated with baseline total PSA, with Gleason score and with pathological stage; patients with a NLR >3 has a higher incidence of recurrence. In multivariate analysis including age, total PSA and NLR, NLR is the most important factor able to predict recurrence. There are some limitations to this study; first, this is a retrospective study, and the total number of patients analyzed is relatively small. Conclusions: Our study suggests that pre-treatment NLR may be associated with disease free survival in patients with prostate cancer, and could be introduced in clinical practice. NLR has the advantage of low economic cost and wide availability

The starvation symptom inventory: development and psychometric properties

Background: Starvation symptoms are common in patients with anorexia nervosa, and according to the transdiagnostic cognitive behavioural theory for eating disorders, they contribute to maintaining the eating disorder psychopathology. The aim of this study was therefore to describe the design and validation of the Starvation Symptoms Inventory (SSI); a self-report questionnaire that examines the symptoms of starvation in underweight patients with eating disorders. Methods: 150 female patients with anorexia nervosa were recruited, as well as 341 healthy control subjects, 30 not-underweight patients with an eating disorder, and 15 patients with bipolar depressive episodes. The 150 patients completed the Eating Disorder Examination Questionnaire and the Brief Symptom Inventory. All participants rated their starvation symptoms on a continuous Likert-type scale (0-6), and reported the number of days in which they had experienced them in the previous 28 days. Results: Principal component analysis identified a single-factor, 15-item scale, which demonstrated good internal consistency (\u3b1 = 0.91) and test-retest reliability (r = 0.90). The SSI global score was significantly correlated with eating disorder and general psychopathology, demonstrating good convergent validity. SSI scores were significantly higher in the anorexia nervosa sample than in the healthy control, not-underweight eating disorder and bipolar depressive episode samples. Conclusions: These findings suggest that the SSI is a valid self-report questionnaire that may provide important clinical information regarding symptoms of starvation in patients with anorexia nervosa