Cooperative Traffic Control Solution for Vehicle Transition from Autonomous to Manual Mode exploiting Cellular Vehicle-to-Everything (C-V2X) Technology

Nowadays, automated vehicles represent a promising technology to face the stringent requirements for safety and traffic efficiency in the automotive environment. Driving responsibilities will be gradually addressed to the machine, and the role of human pilots will be progressively reduced to passengers. The interaction between passengers and the automated system will create different risks that have not been considered in the past. In particular, the transition between autonomous and manual mode is understood as a risky situation. During the transition, the driver manifests driving irregularities and loss of situation awareness that may endanger himself and other participants on the road. Hence, the vehicle transitioning needs a higher quantity of space around it to be considered safe. However, no effective solution has been developed yet. This thesis aims to design a cooperative traffic control solution that will manage the movements of the group of vehicles to increase the free space around the one transitioning. It will exploit another tool that will play a fundamental role in the future of the automotive industry: connected vehicles technology. C-V2X technology will create a medium for vehicles to exchange information and cooperate. A controller managing the cooperation between vehicles has been developed to help a smooth and safe vehicle repositioning. The controller will be positioned in a centralized computing facility and it will communicate with all the vehicles. The controller defines rules to move vehicles together and enlarge the free space around the vehicle transitioning without collisions. The rules are modeled by a spring-mass-damper system, that can be exploited to control the longitudinal behavior of automated vehicles. In particular, the spring-mass-damper system can manage smooth migration between vehicle dispositions without oscillations. A computer simulation is used to test the performance of the proposed traffic control system. The simulation environment is constituted by three main components: traffic flow, controller and communication network. It has been tested with the software VEINS, which provides interaction between a network simulator (OMNeT++) and a traffic simulator (SUMO). The traffic flow represents the interactions between vehicles. The controller analyzes the data and sends control messages to all vehicles. The communication network will share the data concerning vehicles’ position and speed and control messages. The proposed cooperative vehicle control system demonstrated to reduce the risks of the transition with the smooth motion of vehicles. The controller is able to achieve the safety requirements without reducing the level of comfortability of vehicles’ passengers

Cambiamenti climatici e sicurezza alimentare

This paper presents an overview of the recent scientific literature on the link between food production and climate change, both for present and future impacts of climate changes, and for the contribution that policies and measures in the sector of food production and consumption can give to reduce greenhouse gas emissions. Many available studies show that agriculture and food production are inherently sensitive to climate variability and change, as a result of either natural causes or human activities, and outline the likely direct influences of climate change on crops production system for food and fodder, as well as other indirect impacts on the health of livestock, and on trade of food and food products. Conclusions common to the different studies are: a) the improvement of model projections of the effects of climate change at regional and local level is crucial to better define the impacts and steer the decision-making process of adaptation of food systems; b) the impacts of climate change on food security will be greater in countries which already suffer from high levels of hunger and are vulnerable to the effects of extreme weather events, are potentially large and will grow in the future if adaptive responses will not be implemented; d) although the climate crisis is mainly related to energy production, food production will play an important role both for the contribution to the reduction of greenhouse gas emissions from agricultural and livestock activities and for the control of deforestation

Full Sky Study of Diffuse Galactic Emission at Decimeter Wavelengths

A detailed knowledge of the Galactic radio continuum is of high interest for studies of the dynamics and structure of the Galaxy as well as for the problem of foreground removal in Cosmic Microwave Background measurements. In this work we present a full-sky study of the diffuse Galactic emission at frequencies of few GHz, where synchrotron radiation is by far the dominant component. We perform a detailed combined analysis of the extended surveys at 408, 1420 and 2326 MHz (by Haslam et al. 1982, Reich 1982, Reich & Reich, 1986 and Jonas et al. 1998, respectively). Using the technique applied by Schlegel et al. (1998) to the IRAS data, we produce destriped versions of the three maps. This allows us to construct a nearly-full-sky map of the spectral index and of the normalization factor with sub-degree angular resolution. The resulting distribution of the spectral indices has an average of beta = 2.695 and dispersion sigma_{beta} = 0.120. This is representative for the Galactic diffuse synchrotron emission, with only minor effects from free-free emission and point sources.Comment: 10 pages, 16 jpeg figures, accepted to Astronomy & Astrophysics, Comments and figure adde

Impact of the dropping activity with vehicle age on air pollutant emissions

Road transport is a major source of air pollution especially in cities. Detailed calculations are needed to support road transport emission inventories due to the variance of technologies and operating conditions encountered on the roads. The annual distance driven by cars in relation to their characteristics is an important variable in such calculations. In this work, a large amount of mileage data were collected from second–hand car sellers in Italy and were then analyzed in order to understand the influence of vehicle age on annual mileage driven. The available data enabled the development of dropping functions of annual mileage with vehicle age. It was found that the average mileage of 10 year old cars is only approximately 40% of the mileage driven on year one. This drops to approximately only 10% for 20–year old cars. The findings are of paramount importance in environmental calculations as road transport NOX and PM emissions drop by more than 20% when the corrected functions are used compared to using a constant mileage. Not introducing such a correction may result to an approximately 8% higher nation–wide NOX emissions with negative implications towards meeting the national emission ceilings. In terms of policy implications, the dropping activity with age results to a decrease in the importance of accelerated scrappage schemes and of environmental zones in air quality

Impact of the dropping activity with vehicle age on air pollutant emissions

AbstractRoad transport is a major source of air pollution especially in cities. Detailed calculations are needed to support road transport emission inventories due to the variance of technologies and operating conditions encountered on the roads. The annual distance driven by cars in relation to their characteristics is an important variable in such calculations. In this work, a large amount of mileage data were collected from second–hand car sellers in Italy and were then analyzed in order to understand the influence of vehicle age on annual mileage driven. The available data enabled the development of dropping functions of annual mileage with vehicle age. It was found that the average mileage of 10 year old cars is only approximately 40% of the mileage driven on year one. This drops to approximately only 10% for 20–year old cars. The findings are of paramount importance in environmental calculations as road transport NOX and PM emissions drop by more than 20% when the corrected functions are used compared to using a constant mileage. Not introducing such a correction may result to an approximately 8% higher nation–wide NOX emissions with negative implications towards meeting the national emission ceilings. In terms of policy implications, the dropping activity with age results to a decrease in the importance of accelerated scrappage schemes and of environmental zones in air quality

Domestic heating from forest logging residues: environmental risks and benefits

The European Union (EU) relies largely on bioenergy to achieve its climate and energy targets for 2020 and beyond. Special focus is placed on utilization of biomass residues, which are considered to cause low environmental impacts. We used the dataset from the latest European Commission document on the sustainability of solid and gaseous biomass (SWD2014 259), complementing those results by: i) designing three pathways for domestic-heat production using forest logging residues, with different combustion technologies; ii) expanding the analysis to include forest carbon stock development with and without bioenergy; iii) using absolute climate metrics to assess the surface temperature response by the end of the century to a bioenergy and a reference fossil system; iv) including multiple climate forcers (well-mixed GHG, near term climate forcers and surface albedo change); iv) quantifying life cycle impacts on acidification, particulate matter emissions and photochemical ozone formation; v) reviewing potential risks for forest ecosystem degradation due to increased removal of residues. Supply-chain GHG savings of the three pathways analysed ranged between 80% and 96% compared to a natural gas system, above the 70% threshold suggested by the EU. However, the climate impact of bioenergy should be assessed by considering also the non-bioenergy uses of the biomass and by including all climate forcers. We calculate the Surface Temperature Response to bioenergy and fossil systems by means of Absolute Global surface Temperature Potential (AGTP) metric. Domestic heating from logging residues is generally beneficial to mitigate the surface temperature increase by 2100 compared to the use of natural gas and other fossil sources. As long as residues with a decay rate in the forest higher than 2.7%*yr1 are considered as feedstock, investing now in the mobilization of residues for heat production can reduce the temperature increase by 2100 compared to all the fossil sources analysed, both in case of bioenergy as a systemic change or in case of bioenergy as a transitory option. Furthermore, several environmental risks are associated with the removal and use of forest logging residues for bioenergy. These issues concern mostly local air pollution, biodiversity loss and, mainly for stumps removal, physical damage to forest soils. Forest logging residues are not free of environmental risks. Actions promoting their use should consider: (i) that climate change mitigation depends mainly on the decay rate of biomass under natural decomposition and time and rate of technology deployment, (ii) whether management guidelines aimed at protecting long-term forest productivity are in place and (iii) whether proper actions for the management of adverse effects on local air pollution are in place

Addio agli studi: L impatto dei fattori sociali e delle motivazioni individuali sulla scelta di abbandonare l universita

Il nucleo centrale del lavoro consiste proprio nel tentativo di identificare i differenti ordini di motivazioni che si trovano all origine della scelta di lasciare gli studi, di quantificarne l incidenza e di analizzarne le caratteristiche.Il nucleo centrale del lavoro consiste proprio nel tentativo di identificare i differenti ordini di motivazioni che si trovano all origine della scelta di lasciare gli studi, di quantificarne l incidenza e di analizzarne le caratteristiche

Influence of climate change on the frequency of daytime temperature inversions and stagnation events in the Po Valley: historical trend and future projections

This work analyzes the frequency of days characterized by daytime temperature inversion and air stagnation events in the Po valley area. The analysis is focused on both historical series and future projections under climate change. Historical sounding data from two different Italian stations are used as well as future projections data, provided by CMCC-CCLM 4-8-19 regional climate model (MED-CORDEX initiative). A new method to detect layers of temperature inversion is also presented. The developed method computes the occurrence of a temperature inversion layer for a given day at 12 UTC without a detailed knowledge of temperature vertical profile. This method was validated using sounding data and applied to the model projections, under two different emissions scenarios (RCP4.5 and RCP8.5). Under RCP4.5 intermediate emissions scenario, the occurrence of temperature inversions is projected to increase by 12 days/year (around + 10%) in the last decade of 21st century compared to 1986–2005 average. However, the increase in temperature inversions seems to be especially concentrated in the warm period. Under RCP8.5 extreme scenario, temperature inversions are still projected to increase, though to a lesser extent compared to RCP4.5 scenario (+ 6 days/year in the last decade of 21st century). A similar trend was found also for air stagnation events, which take into account the variation of precipitation pattern and wind strength. The expected increases are equal to + 13 days/year and + 11 days/year in the last decade of 21st century compared to 1986–2005 average, under RCP4.5 and RCP8.5 scenarios respectively

Importance of activity data for improving the residential wood combustion emission inventory at regional level

The contribution of residential wood combustion (RWC) to emission inventory at local level was estimated using a bottomeup approach for the Lombardy Region of North Italy. A survey, based on the CATI (Computer Assisted Telephone Interviewing) method, has been undertaken through 18,000 interviews. The interviews had the objective to characterize the RWC use in this region, in term of both total and municipal wood consumption. Details on the type of appliances used in RWC were also gathered. The results of the survey were then statistically analyzed in order to allow an estimate of RWC with high spatial resolution (i.e., at municipal level) in relation to the size and altitude of the territory. The work provides new evidence of the importance of wood combustion as a key source for PM and NMVOC emissions at local level, and thus highlights the importance of technological improvements and new policies aimed at emission reduction in this sector. Considering the great differences in average PM emission factors between low efficiency appliances (fireplaces, old stoves) and high efficiency ones (new stoves, pellet burners), this work emphasizes the importance of obtaining more detailed information on the types of wood appliances used for arriving at a reliable PM emission inventory for RWC