Traffic Offloading/Onloading in Multi-RAT Cellular Networks

We analyze next generation cellular networks, offering connectivity to mobile users through multiple radio access technologies (RATs), namely LTE and WiFi. We develop a framework based on the Markovian agent formalism, which can model several aspects of the system, including user traffic dynamics and radio resource allocation. In particular, through a mean-field solution, we show the ability of our framework to capture the system behavior in flash-crowd scenarios, i.e., when a burst of traffic requests takes place in some parts of the network service area. We consider a distributed strategy for the user RAT selection, which aims at ensuring high user throughput, and investigate its performance under different resource allocation scheme

Survivability study of a Water Cleaning Facility using Fluid Stochastic Petri Nets

This paper investigates the survivability of a water cleaning facility using Fluid Stochastic Petri Nets (FSPNs). Water cleaning facilities are responsible for providing drinking water to a specific district. The provided service is very important and makes such facilities belong to a nation's critical infrastructures. Therefore, such a facility should be able to recover in a timely manner after the occurrence of disasters. The use of FSPNs in survivability research is new and promising due to its general applicability. In this paper we model and analyze the survivability of of the last phases of the water cleaning process in a Dutch water company. Analysis results identify the weaknesses of the process and redundancy is suggested to improve the survivability

Improved control of water loss from micropropagated grapevines (Vitis vinifera cv. Nebbiolo)

Micropropagated plantlets are generally susceptible to rapid desiccation when exposed to reduced relative humidity and require a costly acclimatization procedure. Detached leaves of micropropagated Vitis vinifera, cv. Nebbiolo, plantlets were used to evaluate the relative contribution of leaf cuticle and stomata to water loss. Water loss occurred mainly from the abaxial surface of detached leaves; moreover, a large majority of stomata was still open 3 h after exposure to 63 % RH. An indirect estimation of epicuticular wax suggested a lower wax deposition for micropropagated plantlets compared to acclimatized and field-grown plants of the same clone. A previously developed method to produce hardened micropropagated plants was adopted: 1 mg(.)l(-1) paclobutrazol (PBZ) was added to the medium and culture vessels with reduced relative humidity (rRH) were used during the last stage of micropropagation. Under our experimental conditions, rRH was more effective to reduce transpiration than PBZ; a combination of both treatments improved plant survival during acclimatization.

Circular Economy: A Performance Evaluation Perspective

Circular Economy has emerged in the last years as an industrial pattern that rethinks the entire design and production cycle of products and goods, to obtain the minimal environmental impact and maximize the energy efficiency. This pattern creates product transformation cycles, that allow to re-use parts and renew energy, defining Circular Economy Ecosystems. Such cycles, are very interesting systems from a performance evaluation point of view: in this paper we give a Colored Petri Net perspective to circular economy. In particular, we focus on an example taken from the literature that considers car manufacturing, and we show how we can deal with the problem using standard performance evaluation techniques. Results from performance analysis of the case study, allow to focus on new interesting metrics and performance indicators, that might not be fully studied with conventional techniques applied by expert of the economical domain

Analysis of an Electric Vehicle Charging System Along a Highway

To reduce carbon emission, the transportation sector evolves toward replacing internal combustion vehicles by electric vehicles (EV). However, the limited driving ranges of EVs, their long recharge duration and the need of appropriate charging infrastructures require smart strategies to optimize the charging stops during a long trip. These challenges have generated a new area of studies that were mainly directed to extend the classical Vehicle Routing Problem (VRP) to a fleet of commercial EVs. In this paper, we propose a different point of view, by considering the interaction of private EVs with the related infrastructure, focusing on a highway trip. We consider a highway where charging stations are scattered along the road, and are equipped withmultiple chargers. Using Fluid Stochastic Petri Nets (FSPN), the paper compares different decision policies when to stop and recharge the battery to maximize the probability of a car to reach its destination and minimize the trip completion time

Region-Based Analysis of Hybrid Petri Nets with a Single General One-Shot Transition

Recently, hybrid Petri nets with a single general one-shot transition (HPnGs) have been introduced together with an algorithm to analyze their underlying state space using a conditioning/deconditioning approach. In this paper we propose a considerably more efficient algorithm for analysing HPnGs. The proposed algorithm maps the underlying state-space onto a plane for all possible firing times of the general transition s and for all possible systems times t. The key idea of the proposed method is that instead of dealing with infinitely many points in the t-s-plane, we can partition the state space into several regions, such that all points inside one region are associated with the same system state. To compute the probability to be in a specific system state at time τ, it suffices to find all regions intersecting the line t = τ and decondition the firing time over the intersections. This partitioning results in a considerable speed-up and provides more accurate results. A scalable case study illustrates the efficiency gain with respect to the previous algorithm

Etiological diagnosis, prognostic significance and role of electrophysiological study in patients with Brugada ECG and syncope.

BACKGROUND: Syncope is considered a risk factor for life-threatening arrhythmias in Brugada patients. Distinguishing a benign syncope from one due to ventricular arrhythmias is often difficult, unless an ECG is recorded during the episode. Aim of the study was to analyze the characteristics of syncopal episodes in a large population of Brugada patients and evaluate the role of electrophysiological study (EPS) and the prognosis in the different subgroups. METHODS AND RESULTS: One hundred ninety-five Brugada patients with history of syncope were considered. Syncope were classified as neurally mediated (group 1, 61%) or unexplained (group 2, 39%) on the basis of personal and family history, clinical features, triggers, situations, associated signs, concomitant therapy. Most patients underwent EPS; they received ICD or implantable loop-recorder on the basis of the result of investigations and physician's judgment. At 62±45months of mean follow-up, group 1 showed a significantly lower incidence of arrhythmic events (2%) as compared to group 2 (9%, p<0.001). Group 2 patients with positive EPS showed the highest risk of arrhythmic events (27%). No ventricular events occurred in subjects with negative EPS. CONCLUSION: Etiological definition of syncope in Brugada patients is important, as it allows identifying two groups with different outcome. Patients with unexplained syncope and ventricular fibrillation induced at EPS have the highest risk of arrhythmic events. Patients presenting with neurally mediated syncope showed a prognosis similar to that of the asymptomatic and the role of EPS in this group is unproven