Minimum Race-Time Planning-Strategy for an Autonomous Electric Racecar

Increasing attention to autonomous passenger vehicles has also attracted interest in an autonomous racing series. Because of this, platforms such as Roborace and the Indy Autonomous Challenge are currently evolving. Electric racecars face the challenge of a limited amount of stored energy within their batteries. Furthermore, the thermodynamical influence of an all-electric powertrain on the race performance is crucial. Severe damage can occur to the powertrain components when thermally overstressed. In this work we present a race-time minimal control strategy deduced from an Optimal Control Problem (OCP) that is transcribed into a Nonlinear Problem (NLP). Its optimization variables stem from the driving dynamics as well as from a thermodynamical description of the electric powertrain. We deduce the necessary first-order Ordinary Differential Equations (ODE)s and form simplified loss models for the implementation within the numerical optimization. The significant influence of the powertrain behavior on the race strategy is shown.Comment: Accepted at The 23rd IEEE International Conference on Intelligent Transportation Systems, September 20 - 23, 202

Identification of lumped stiffness parameters for a motorcycle model in investigating weave and wobble

In motorcycle dynamics, great importance is attributed to the study of the weave and wobble vibration modes and, in particular, to the effects of the flexibility of structural components on their stability. Therefore, appropriate motorcycle models for studying weave and wobble should include flexible elements for describing the flexural behavior of components such as the main frame, front assembly, and rear swingarm. Different approaches are possible formodeling flexibilities: the most common among them are the lumped stiffness and the flexible multibody approaches. While the latter certainly provides higher accuracy, the former has advantages in terms of computational load, but, above all, it makes it easier to understand in the design phase how technical parameters, such as torsional and bending stiffness of a given structural component, can influence the stability of weave and wobble. The accuracy of lumped stiffness models strongly depends on parameter identification. In this study, a general method is proposed to determine appropriate lumped stiffness parameters for any given motorcycle component. The proposed method is tested and validated by comparing the weave and wobble modal behavior with the results of flexible multibody analysis. The lumped stiffness model is then adopted to carry out a sensitivity analysis aimed at identifying the effects on the weave and wobble stability of the torsional and bending stiffness of specific structural components of the motorcycle to optimize their design

Cost-effectiveness of pretransplant sofosbuvir for preventing recurrent hepatitis C virus infection after liver transplantation

Abstract There are reports of pretransplant sofosbuvir (SOF) plus ribavirin being effective in preventing recurrent hepatitis C virus (HCV) infection after liver transplantation (LT). The aim of this study was to assess the cost-effectiveness of this strategy in the area served by the North Italy Transplant program. We retrospectively assessed the impact of HCV infection on post-LT survival in 2376 consecutive adult patients (MELD ≤ 25, unknown genotype, period 2004-2009) and the prevalence costs of conventional standard of care (SOC) antiviral therapy (pegylated interferon plus ribavirin) after LT. A Markov model was developed to compare two strategies: 12-24 weeks of SOF+ ribavirin for pre-LT anti-HCV treatment versus on-demand post-LT SOC antiviral therapy. Among the 1794 patients undergoing LT, 860 (48%) were HCV+ and 50% of them were given SOC therapy after LT (mean cost of drugs and adverse effect management = 14,421€ per patient). HCV etiology had a strong impact on post-LT survival (hazard ratio = 1.59, 95% CI = 1.22-2.09, P = 0.0007). After Monte Carlo simulation, pre-LT SOF therapy showed a median survival benefit of 1.5 quality-adjusted life years and an Incremental cost-effectiveness ratio (ICER) of 30,663€/QALY, proving cost-effective in our particular Italian scenario. The costs of SOF therapy, sustained viral response rate 12 weeks after LT, and recipient's age were the main ICER predictors at multivariate analysis. This study proposes a dynamic model based on real-life data from northern Italy for adjusting the costs of pre-LT direct-acting antiviral therapies to the actual sustained virological response reached after LT. © 2015 Steunstichting ESOT. KEYWORDS: cost-effectiveness analysis; hepatitis C virus infection; liver transplantation; recurrent HCV; sofosbuvi

Post-load insulin resistance does not predict virological response to treatment of chronic hepatitis C patients without the metabolic syndrome.

Abstract BACKGROUND AND AIM: The role of insulin resistance in predicting virological response to therapy of chronic hepatitis C is debated. We assessed the association between basal (defined as homeostasis model assessment of insulin resistance (HOMA-IR)>2) and post-load insulin resistance (as oral glucose insulin sensitivity index<9.8mg/kg/min) with the rapid and sustained virological responses in chronic hepatitis C. METHODS: Observational prospective study of 124 treatment-na\uefve patients with chronic hepatitis C not fulfilling the metabolic syndrome criteria, adherent to a standard treatment with pegylated interferon alpha plus ribavirin. RESULTS: Insulin resistance was detected in 50% (by HOMA-IR) and 29% (by oral glucose insulin sensitivity index) of patients. Independent predictors of rapid virologic response were hepatitis C virus (HCV) genotype 2 (odds ratio 5.66; 95% confidence interval 1.88-17.01), HCV genotype 3 (odds ratio 5.23; 95% confidence interval 1.84-14.84) and lower basal ferritin levels (odds ratio 0.99; 95% confidence interval 0.993-0.998). Independent predictors of sustained virologic response were HCV genotype 2 (odds ratio 19.54; 95% confidence interval 2.29-166.41) and HCV genotype 3 (odds ratio 3.24; 95% confidence interval 1.10-9.58). Rapid virologic response was by itself predictive of sustained virologic response (odds ratio 40.90; 95% confidence interval 5.37-311.53). CONCLUSIONS: Insulin resistance, measured by both static and dynamic methods, does not predict rapid or sustained virologic response in chronic hepatitis C patients without the metabolic syndrome