Effect of Grapevine Age on the Aroma Compounds in ‘Beihong’ Wine

The main aim of this study was to determine the influence of grapevine age (3, 6 and 12 years) on the aromacompounds in ‘Beihong’ wine. Aroma compounds in wine were analyzed by solid-phase microextractiongas chromatography-mass spectrometry (SPME-GC/MS). Thirty-three (33) volatile compounds wereidentified and quantified. The majority of aroma compounds were esters (20) and the concentrationof these totaled 90.63-92.82% (w/w) of the total aroma compounds; particularly, ethyl octanoate andethyl decanoate. Through the descriptive analysis aroma profile for ‘Beihong’ wine, the highest aromacontribution was from the fruity and floral series. As the age of the grapevine increased, the concentrationsof total volatiles and total odor activity values (OAVs) of the wines significantly increased (p < 0.001). Thissuggests that grapevine age could affect berry composition, enhance the content of wine aroma compoundsand improve wine quality

Limitations and Improvements of the Intelligent Driver Model (IDM)

This contribution analyzes the widely used and well-known "intelligent driver model" (briefly IDM), which is a second order car-following model governed by a system of ordinary differential equations. Although this model was intensively studied in recent years for properly capturing traffic phenomena and driver braking behavior, a rigorous study of the well-posedness of solutions has, to our knowledge, never been performed. First it is shown that, for a specific class of initial data, the vehicles' velocities become negative or even diverge to $-\infty$ in finite time, both undesirable properties for a car-following model. Various modifications of the IDM are then proposed in order to avoid such ill-posedness. The theoretical remediation of the model, rather than post facto by ad-hoc modification of code implementations, allows a more sound numerical implementation and preservation of the model features. Indeed, to avoid inconsistencies and ensure dynamics close to the one of the original model, one may need to inspect and clean large input data, which may result practically impossible for large-scale simulations. Although well-posedness issues occur only for specific initial data, this may happen frequently when different traffic scenarios are analyzed, and especially in presence of lane-changing, on ramps and other network components as it is the case for most commonly used micro-simulators. On the other side, it is shown that well-posedness can be guaranteed by straight-forward improvements, such as those obtained by slightly changing the acceleration to prevent the velocity from becoming negative.Comment: 29 pages, 23 Figure

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

Mathematical Models and Control Algorithms for Traffic Automation

Transportation accounts for 28% of energy consumptionin the US, with 75% of that occurring on highways. Workers spent on aggregate over three million driver-years commuting to their jobs, contributing significantly to the nation-wide congestion. Based on 2012 estimates, US commuters experienced an average of 52 hours of delay in 2011, which amounts to $121 billion of fuel costs and opportunity costs due to delay annually. Estimates project that 4.2% of fuel will be wasted in congestion in 2050 with the adoption of autonomous vehicles. Mixed autonomy, the intermediate regime between a system with no adoption of autonomy and a system where autonomy is fully employed, is proposed as a potential solution to fuel consumption reduction and flow capacity improvement.The mixed autonomy is complicated to characterize and hard to tackle due to the degree of uncertainty in the system dynamics. The understanding of mixed autonomy is however crucial to designing automated and intelligent transportation systems, and to overhauling public policy with autonomous vehicles in the loop.Approaches to mobile traffic control include machine learning methods, mathematical modeling and optimal control. The machine learning approaches achieve strong empirical results but in general lack optimality guarantees, theoretical studies of the convergence rate, out-of-sample performance guanrantees and interpretability. The mathematical approaches, on the other hand, are supported by highly developed mathematical theory, but suffer from a lack of attention to the theoretical characterization to the model solutions and the actuations function space. This is inevitable as mathematical methods trade model complexity for the tractability of analysis in the optimal control design.This thesis investigates mathematical models and control algorithms for traffic automation at multiple levels. At the vehicle level, this thesis demonstrates the lack of guarantee of well-posedness for the solution of the intelligent driver model (IDM) and closes the theoretical gap by proposing several modifications and rigorously showing the existence and uniqueness of their solutions. At the mixed autonomy vehicle control level, a systematic way to design the basis-based feedback controller is introduced, which is defined by the solution of a finite-dimensional constrained optimization problem. This thesis discusses theoretical characterization of the actuation function space. An optimal Legendre polynomial basis controller is trained with field data and has been evaluated with simulation data and compared with a range of other mobile traffic controllers. At the full origin-destination demand routing level, this thesis studies the repeated routing game problem on a parallel network with affine latency functions on each edge, transforming the dynamic traffic assignment problem into a control-theoretic problem. The impact of model parameters on the traffic performance is theoretically studied, andan algorithmic solution based on explicit model predictive control (MPC) is proposed