Numerical Method For Tsunami Calculation Using Full Navier -Stokes Equations And The Volume Of Fluid Method

Thesis (Ph.D.) University of Alaska Fairbanks, 2006A two-dimensional numerical model was developed to study tsunami wave generation, propagation and runup. The model is based on solving the Navier-Stokes (NS) equations. The free-surface motion is tracked using the Volume of Fluid technique. The finite difference two-step projection method is used to solve NS equations and the forward time difference method to discretize the time derivative. A structured mesh is used to discretize the spatial domain. The model has been conceived as a versatile, efficient and practical numerical tool for tsunami computation, which could address a comprehensive understanding of tsunami physics with the ultimate aim of mitigating tsunami hazards. The prediction capability of tsunami generation, propagation and runup is improved by including more accurately the effects of vertical velocity/acceleration, dispersion and wave breaking. The model has the capability to represent complex curved boundaries within a Cartesian grid system and to deal with arbitrary transient-deformed moving boundaries. The numerical model was validated using laboratory experiments and analytical solutions. The model was used as a tool to determine the adequacy of the shallow water (SW) approximation in the application of tsunami simulations. Numerical results were compared with experimental data, analytical solutions and SW results in terms of the time-history free surface elevations and velocity. Reasonable agreements were observed based on the spatial and temporal distributions of the free surface and velocity

Social Pressure or Rational Reactions to Incentives? A Historical Analysis of Reasons for Referee Bias in the Spanish Football

A relevant question in social science is whether cognitive bias can be instigated by social pressure or is it just a rational reaction to incentives in place. Sport, and association football in particular, offers settings in which to gain insights into this question. In this paper we estimate the determinants of the length of time between referee appointments in Spanish soccer as a function of referee decisions in favour of the home and away team in the most recent match by means of a deep-learning model. This approach allows us to capture all interactions among a high-dimensional set of variables without the necessity of specifying them beforehand. Furthermore, deep-learning models are nowadays the state of the art among the predicting models which are needed and here used for estimating effects of a cause. We do not find strong evidence of an incentive scheme that counteracts well-known home referee biases. Our results also suggest that referees are incentivised to deliver a moderate amount of surprise in the outcome of the game what is consistent with the objective function of consumers and tournament organisers

Numerical Simulation and Hydrodynamic Performance Predicting of 2 Two-Dimensional Hydrofoils in Tandem Configuration

In this study we investigated the performance of NACA 0012 hydrofoils aligned in tandem using parametric method and Neural Networks. We use the 2D viscous numerical model (STAR-CCM+) to simulate the hydrofoil system. To validate the numerical model, we modeled a single NACA 0012 configuration and compared it to experimental results. Results are found in concordance with the published experimental results. Then two NACA 0012 hydrofoils in tandem configuration were studied in relation to 788 combinations of the following parameters: spacing between two hydrofoils, angle of attack (AOA) of upstream hydrofoil and AOA of downstream hydrofoil. The effects exerted by these three parameters on the hydrodynamic coefficients Lift coefficient (CL), Drag Coefficient (CD) and Lift-Drag Ratio (LDR), are consistent with the behavior of the system. To establish a control system for the hydrofoil craft, a timely analysis of the hydrodynamic system is needed due to the computational resource constraints, analysis of a large combination and time consuming of the three parameters established. To provide a broader and faster way to predict the hydrodynamic performance of two hydrofoils in tandem configuration, an optimal artificial neural network (ANN) was trained using the large combination of three parameters generated from the numerical simulations. Regression analysis of the output of ANN was performed, and the results are consistent with numerical simulation with a correlation coefficient greater than 99.99%. The optimized spacing of 6.6c are suggested where the system has the lowest CD while obtaining the highest CL and LDR. The formula of the ANN was then presented, providing a reliable predicting method of hydrofoils in tandem configuration

Attendance demand in a developing football market: the case of the Peruvian First Division

Research question: Most of the empirical research on football demand has focused on leagues in developed countries while those in developing countries have received comparatively limited attention. In the absence of more specific analyses of leagues in developing countries, an implicit assumption is that the demand for football across different economies is homogenous. However, such an assumption may lead to inappropriate policies. Therefore, decision-making and policies aimed at attendance and pricing in developing countries should be substantiated with empirical evidence reflecting their settings. Research methods: This paper models match level attendance demand and price in the first tier of the Peruvian football league from 2012 to 2016 inclusive. Using a sample of 1719 matches, two-stage least-squares estimation with instrumental variables is used. Results and findings: We find that attendance in the Peruvian football league is driven by market size, distance between teams and recent performance while local rivalry and price do not exert significant impacts. More importantly, attendance exhibits properties of an inferior good given its relationship with levels of poverty and associated correlation with income. Implications: The implications are that demand models for football in developing and developed economies generate different results as the impacts of some exogenous variables on attendance offer different outcomes. For example, the impact of price and income differ from prior expectations indicating that different approaches are necessary to managing football in developing countries including distinct policies on stadium accommodation

Psychometric properties of the Spanish version of the once-daily Urticaria Activity Score (UAS) in patients with chronic spontaneous urticaria managed in clinical practice (the EVALUAS study)

Background: The daily diary Urticaria Activity Score (UAS) and its weekly score (UAS7) are widely used to assess signs and symptoms in patients with chronic spontaneous urticaria (CSU). The objective of this study was to assess the psychometric properties of a Spanish version of the once-daily UAS. Methods: Observational study in patients ≥18 years old receiving usual care for CSU (daily or almost daily occurrence of generalized hives or angioedema for ≥6 weeks). Patients were included consecutively and completed the UAS, EQ5D, and the Chronic Urticaria Quality of Life scale (CU-Q2oL) at two study visits 6 weeks apart. On each occasion, the UAS was completed once-daily for 7 consecutive days to be able to calculate the UAS7 score. Psychometric properties of reliability, construct validity, and responsiveness were assessed. The Minimal Important Difference (MID) was estimated for the UAS7 using anchor- and distribution-based approaches. Results: Data from 166 patients was available for analysis (mean age 49 years, 65.7% female). Floor (5.4% of patients with the lowest possible score) and ceiling (1.2%) effects were low; 15% of patients had missing values. Internal consistency and test-retest reliability were good (Cronbach’s alpha of 0.83 and an ICC of 0.84, respectively). Convergent validity was demonstrated through the pattern of correlations with the EQ-5D and CU-Q2oL and known groups’ validity was demonstrated by the instrument’s ability to discriminate between patients with different overall levels of urticaria severity, with between-group effect-sizes (ES) ranging from 0.36 to 1.19. The UAS7 proved responsive to change with effect sizes ranging from 0.3 to 1.52 in patients reporting improvement or deterioration in overall urticaria status. The MID for the UAS7 score was estimated at 7–8 points, on a scale of 0–42. Conclusions: The Spanish version of the UAS score has demonstrated a robust psychometric performance in patients with CSU managed in conditions of usual care. It can therefore be considered a suitable instrument to assess disease activity in clinical practice in Spanish-speaking patients. The Spanish version’s reliability and validity are similar to those reported for other language versions of the once- and twice-daily variants of the UAS

Effects of Albumin Treatment on Systemic and Portal Hemodynamics and Systemic Inflammation in Patients With Decompensated Cirrhosis

We investigated the effect of albumin treatment (20% solution) on hypoalbuminemia, cardiocirculatory dysfunction, portal hypertension, and systemic inflammation in patients with decompensated cirrhosis with and without bacterial infections. We performed a prospective study to assess the effects of long-term (12 weeks) treatment with low doses (1 g/kg body weight every 2 weeks) and high doses (1.5 g/kg every week) of albumin on serum albumin, plasma renin, cardiocirculatory function, portal pressure, and plasma levels of cytokines, collecting data from 18 patients without bacterial infections (the Pilot-PRECIOSA study). We also assessed the effect of short-term (1 week) treatment with antibiotics alone vs the combination of albumin plus antibiotics (1.5 g/kg on day 1 and 1 g/kg on day 3) on plasma levels of cytokines in biobanked samples from 78 patients with bacterial infections included in a randomized controlled trial (INFECIR-2 study). Circulatory dysfunction and systemic inflammation were extremely unstable in many patients included in the Pilot-PRECIOSA study; these patients had intense and reversible peaks in plasma levels of renin and interleukin 6. Long-term high-dose albumin, but not low-dose albumin, was associated with normalization of serum level of albumin, improved stability of the circulation and left ventricular function, and reduced plasma levels of cytokines (interleukin 6, granulocyte colony-stimulating factor, interleukin 1 receptor antagonist, and vascular endothelial growth factor) without significant changes in portal pressure. The immune-modulatory effects of albumin observed in the Pilot-PRECIOSA study were confirmed in the INFECIR-2 study. In this study, patients given albumin had significant reductions in plasma levels of cytokines. In an analysis of data from 2 trials (Pilot-PRECIOSA study and INFECIR-2 study), we found that albumin treatment reduced systemic inflammation and cardiocirculatory dysfunction in patients with decompensated cirrhosis. These effects might be responsible for the beneficial effects of albumin therapy on outcomes of patients with decompensated cirrhosis. ClinicalTrials.gov, Numbers: NCT00968695 and NCT03451292

Validation and inter-comparison of models for landslide tsunami generation

10.1016/j.ocemod.2021.101943OCEAN MODELLING17