Models and Performance of VANET based Emergency Braking

The network research community is working in the field of automotive to provide VANET based safety applications to reduce the number of accidents, deaths, injuries and loss of money. Several approaches are proposed and investigated in VANET literature, but in a completely network-oriented fashion. Most of them do not take into account application requirements and no one considers the dynamics of the vehicles. Moreover, message repropagation schemes are widely proposed without investigating their benefits and using very complicated approaches. This technical report, which is derived from the Master Thesis of Michele Segata, focuses on the Emergency Electronic Brake Lights (EEBL) safety application, meant to send warning messages in the case of an emergency brake, in particular performing a joint analysis of network requirements and provided application level benefits. The EEBL application is integrated within a Collaborative Adaptive Cruise Control (CACC) which uses network-provided information to automatically brake the car if the driver does not react to the warning. Moreover, an information aggregation scheme is proposed to analyze the benefits of repropagation together with the consequent increase of network load. This protocol is compared to a protocol without repropagation and to a rebroadcast protocol found in the literature (namely the weighted p-persistent rebroadcast). The scenario is a highway stretch in which a platoon of vehicles brake down to a complete stop. Simulations are performed using the NS_3 network simulation in which two mobility models have been embedded. The first one, which is called Intelligent Driver Model (IDM) emulates the behavior of a driver trying to reach a desired speed and braking when approaching vehicles in front. The second one (Minimizing Overall Braking Induced by Lane change (MOBIL)), instead, decides when a vehicle has to change lane in order to perform an overtake or optimize its path. The original simulator has been modified by - introducing real physical limits to naturally reproduce real crashes; - implementing a CACC; - implementing the driver reaction when a warning is received; - implementing different network protocols. The tests are performed in different situations, such as different number of lanes (one to five), different average speeds, different network protocols and different market penetration rates and they show that: - the adoption of this technology considerably decreases car accidents since the overall average maximum deceleration is reduced; - network load depends on application-level details, such as the implementation of the CACC; - VANET safety application can improve safety even with a partial market penetration rate; - message repropagation is important to reduce the risk of accidents when not all vehicles are equipped; - benefits are gained not only by equipped vehicles but also by unequipped ones

Sharp estimates for the anisotropic torsional rigidity and the principal frequency

In this paper we generalize some classical estimates involving the torsional rigidity and the principal frequency of a convex domain to a class of functionals related to some anisotropic non linear operators

Diffusion enhancement and Taylor dispersion for rotationally symmetric flows in discs and pipes

In this note, we study the long-time dynamics of passive scalars driven by rotationally symmetric flows. We focus on identifying precise conditions on the velocity field in order to prove enhanced dissipation and Taylor dispersion in three-dimensional infinite pipes. As a byproduct of our analysis, we obtain an enhanced decay for circular flows on a disc of arbitrary radius.Comment: 9 pages, comments welcom

Postoperative care in finger replantation. Our case-load and review of the literature

OBJECTIVE: Technical success of a finger replantation depends on several factors such as surgical procedure, type of injury, number of segments amputated, amputation level and individual patient factors. Among early complications that can occur in this type of surgery the onset of venous or arterial thrombosis is the most dreaded. Local irrigating solutions, oral and intravenous anticoagulants, thrombolytic agents, plasma expanders, vasodilating, and antiaggregant drugs are routinely used in patients undergoing microvascular procedures, but currently there is only a non-standardized practice based on anecdotal personal experience. MATERIALS AND METHODS: The aim of our study is to review selected literature relating to perioperative therapy in microsurgical digital replantation. We also report our case-load of 16 patients with finger avulsion describing our particular protocol for postoperative anticoagulation and restoration of fluid and electrolyte balance. RESULTS: Following our daily pharmacological protocol, the postoperative course of the replanted fingers was uneventful. The survival rate for finger replantations performed was 100% (n = 16) with no need for surgical revisions. CONCLUSIONS: The association Dextran-40/Heparin/fluids in the proposed standardized pro-weight pharmacological protocol is an optimal postoperative prophylactic/therapeutic plan to reduce the incidence of endovascular thrombosis after replantation, so ensuring high rate of success in microvascular surgery

Detection of REM Sleep Behaviour Disorder by Automated Polysomnography Analysis

Evidence suggests Rapid-Eye-Movement (REM) Sleep Behaviour Disorder (RBD) is an early predictor of Parkinson's disease. This study proposes a fully-automated framework for RBD detection consisting of automated sleep staging followed by RBD identification. Analysis was assessed using a limited polysomnography montage from 53 participants with RBD and 53 age-matched healthy controls. Sleep stage classification was achieved using a Random Forest (RF) classifier and 156 features extracted from electroencephalogram (EEG), electrooculogram (EOG) and electromyogram (EMG) channels. For RBD detection, a RF classifier was trained combining established techniques to quantify muscle atonia with additional features that incorporate sleep architecture and the EMG fractal exponent. Automated multi-state sleep staging achieved a 0.62 Cohen's Kappa score. RBD detection accuracy improved by 10% to 96% (compared to individual established metrics) when using manually annotated sleep staging. Accuracy remained high (92%) when using automated sleep staging. This study outperforms established metrics and demonstrates that incorporating sleep architecture and sleep stage transitions can benefit RBD detection. This study also achieved automated sleep staging with a level of accuracy comparable to manual annotation. This study validates a tractable, fully-automated, and sensitive pipeline for RBD identification that could be translated to wearable take-home technology.Comment: 20 pages, 3 figure

Environmental and geostrategic effects of raw materials supply supporting the energy transition and electric mobility: a focus on the “lithium triangle” in South America

Electric vehicles (EVs) are breaking through, new incentives and new targets come to light to get the numbers that allow to reduce greenhouse gases over the next 30 years. On the current market, the automotive sector mainly make use of lithium-ion batteries (LIBs) as energy storage systems. The paper examines the distribution of raw materials useful for the realization of LIBs. The availability of the world reserves of these elements is analyzed by presenting an index that highlights the risk of exhaustion of a resource based on economic trends, future objectives and recycling capabilities state-of-the-art. The focus is then on the South American “Lithium Triangle” where the metal is extracted through brine mining and where the environmental and social problems as the geostrategic aspects have been analyzed

Dynamic Model Tests on Gravity Retaining Walls with Various Surcharge Conditions

Seismic design of retaining walls is traditionally based on the Mononobe-Okabe method of analysis. In recent years a number of theoretical analyses have been presented to predict the seismic behaviour of gravity retaining walls. In this paper some shaking table tests performed on a small prototype of gravity wall retaining dry sand are described and the experimental results are presented with the aim to provide, though qualitatively, an insight into some important aspects of the dynamic behaviour of retaining structures resting on rigid foundation soil. The M-O theory do not consider the particular boundary condition that in the practical design of retaining structures are often in use like backfill geometries or loading condition. Shaking table studies were carried out in order to study the dynamic behaviour of gravity retaining walls resting on rigid foundation soil. Two different system have been taken into consideration namely, a wall retaining a horizontal backfill on which uniform surcharge was placed and a wall on which the uniform surcharge was placed to a distance «d» to the head of the wall

Cutting-edge tools for spring monitoring and groundwater system characterization in mountain environments

Mountain aquifers represent one of the largest and most valuable water sources, necessary to meet the population's water needs. Over time, they have been threatened by huge anthropogenic exploitation activities, which are currently leading to the depletion of aquifers in many regions worldwide. Furthermore, the vulnerability of groundwater resources is rapidly increasing due to climate change, urbanization, massive industry production, intensive agriculture, and breeding. Knowledge and forecasting about groundwater flow systems are required to guarantee proper management and territorial planning strategies, according to the mountain environmental evolution taking place. Besides, examining how groundwater storage mechanisms in different regions have changed in response to both climate-driven and anthropogenic effects is becoming increasingly crucial. In remote alpine areas, continuous monitoring and data collection of springs’ hydrogeological parameters is still often hampered by technical and logistical problems. In these contexts, new automated techniques and tools need to be applied to monitor springs’ hydrogeological parameters, punctually understanding the dynamics of exhausting of the available groundwater resources. The instrumentation and sensors complex, installed in correspondence with the Mascognaz spring basin (Aosta Valley, Italy) allows detailed analyses of the surface and underground groundwater system, recording continuously hydrogeological variables entering and leaving the spring recharge system. A cutting-edge weather station was here combined with a spring monitoring system through snowpack-hydrometeorological sensors installation. This setup, composed of a snow scale, ultrasonic and laser sensors for snow weight and snow depth reading, provides the possibility of a detailed study of the snow layer evolution during each season. Besides, a multiparametric probe allows water discharge, temperature and electric conductivity values detection. The high quality of the data provided and the small-size basin features have permitted highlighting the variables affecting the system and standing out those are evolving in time. Besides, the relationship between changes in weather conditions and water availability can be defined by performing correlations between different hydrogeological and meteorological available data series. The Mascognaz spring’s pilot site could be helpful as an example for other researchers and authorities who need to identify suitable instruments, sensors and methods to reconstruct the groundwater flow system and hydrogeological structure of a mountain basin

Recognition and treatment of peri-implant mucositis: Do we have the right perception? A structured review

Peri-implant mucositis is a common inflammatory lesion of the soft tissues surrounding endosseous implants, with no loss of the supporting bone. Its prevention or early diagnosis are vital for dental implant success.The aim of this review was to investigate knowledge strengths and gaps in clinicians'perceptions of periimplant mucositis prevalence and evidence for successful treatment.A literature search for articles published until 2020, reporting on the prevalence of peri-implant mucositis and its treatment was performed in standard online databases. The inclusion criteria were as follows: studies in English; studies with an available abstract; studies on humans with at least 1 dental implant; and studies reporting on the prevalence and/or treatment of peri-implant mucositis. Sixty-five studies fulfilled the inclusion criteria. The included papers were analyzed to identify data on the prevalence and treatment of peri-implant mucositis. The prevalence statistics for peri-implant mucositis had wide ranges in both the patient-based (PB) analysis and the implant-based (IB) analysis; the possible reasons for these wide ranges are discussed. Treatment methods for peri-implant mucositis were analyzed individually and compared to the management of gingivitis.It was determined that the currently available information on the prevalence rates and the standardized therapeutic protocols for peri-implant mucositis are insufficient. Since the mean gingivitis and peri-implant mucositis prevalence rates in the PB analysis were similar, it is possible that peri-implant mucositis is under estimated due to variables related to implant rehabilitation itself