1,720,994 research outputs found
Random Bad State Estimator to Address False Data Injection in Critical Infrastructures
No full textGiven their crucial role for a society and economy, an essential component of critical infrastructures is the Bad State Estimator (BSE), responsible for detecting malfunctions affecting elements of the physical infrastructure. In the past, the BSE has been conceived to mainly cope with accidental faults, under assumptions characterizing their occurrence. However, evolution of the addressed systems category consisting in pervasiveness of ICT-based control towards increasing smartness, paired with the openness of the operational environment, contributed to expose critical infrastructures to intentional attacks, e.g. exploited through False Data Injection (FDI). In the flow of studies focusing on enhancements of the traditional BSE to account for FDI attacks, this paper proposes a new solution that introduces randomness elements in the diagnosis process, to improve detection abilities and mitigate potentially catastrophic common-mode errors. Differently from existing alternatives, the strength of this new technique is that it does not require any additional components or alternative source of information with respect to the classic BSE. Numerical experiments conducted on two IEEE transmission grid tests, taken as representative use cases, show the applicability and benefits of the new solution
TAPAS: a Tool for Stochastic Evaluation of Large Interdependent Composed Models with Absorbing States
No full textTAPAS is a new tool for efficient evaluation of dependability and performability attributes of systems composed of many interconnected components. The tool solves homogeneous continuous time Markov chains described by stochastic automata network models structured in submodels with absorbing states. The measures of interest are defined by a reward structure based on submodels composed through transition-based synchronization. The tool has been conceived in a modular and flexible fashion, to easily accommodate new features. Currently, it implements an array of state-based solvers that addresses the state explosion problem through powerful mathematical techniques, including Kronecker algebra, Tensor Trains and Exponential Sums. A simple, yet representative, case study is adopted, to present the tool and to show the feasibility of the supported methods, in particular frommemory consumption point of view
Dependability of Iterative Software: a Model for Evaluating the Effects of Input Correlation
No full textQuantification of Dependencies between Electrical and Information Infrastructures
No full textIn this paper we present an approach to model and quantify (inter)dependencies between the Electrical Infrastructure (EI) and the Information Infrastructure (II) that implements the EI control and monitoring system. The quantification is achieved through the integration of two models: one that concentrates more on the structure of the power grid and its physical quantities and one that concentrates on the behavior of the control system supported by the II. The modeling approach is exemplified on a scenario whose goal is to study the effects of an II partial failure (a denial of service attack that compromises the communication network) on the remote control of the EI. The approach has been initially developed as part of the European project CRUTIAL
Failure management strategies for IoT-based railways systems
No full textRailways monitoring and control are currently performed by different heterogeneous vertical systems working in isolation without or with limited cooperation among them. Such configuration, widely adopted in practical deployments today, is in contrast with the integrated vision of systems that are at the foundation of the smart-city concept. In order to overcome the current fractured ecosystem that monitors and controls railways functionalities, the adoption of a novel integrated approach is mandatory to create an all-in-one railway system. To this aim, new IoT-based communication technologies, like wireless or Power Line Communication technologies, are considered the main enablers to integrate in a very rapid and easy manner existing vertical systems. In this work, we analyse the architecture of future railways systems based on a mix of wireless and Power Line Communication technologies. In our analysis, we aim at studying possible failure management strategies on rail-road switches to improve the level of reliability, crucial requirement for systems that demand maximum resiliency as they manage a critical function of the infrastructure. In particular, we propose a set of solutions aimed at detecting and handling network and sensor failures to ensure continuity in the execution of the basic control functions. The proposed approach is evaluated by means of simulations and demonstrated to be effective in ensuring a good level of performance even when failures occur
Paralytic ileus, a new rare complication of 5-FU: A case report
No full textFluorouracil (5-FU) is a commonly used chemotherapeutic agent for a
variety of tumor types, intravenously. Although capecitabine and tegafut,
5-FU oral prodrugs, induce rarely paralytic ileus, this particular intestinal
toxicity has never been attributed to 5-FU. Paralytic ileus (or adynamic
ileus) refers to a lack of passage of intestinal contents due to disturbances
of normal intestinal motility, in absence of mechanical obstruction. A lot of
anticancer drug, target-therapy drugs too, are the most common causes of
this toxitity. The clinical case in local Lanciano Hospital we present is of a
patient diagnosed as having colon cancer and he was admitted with
paralytic ileus following adjuvant treatment with 5-FU (Mayo-clinic
schedule). Naranjo, Jones algoritms suggest a direct casual relationship.
Our case, to our knowledge, represents the first published report of this
particular intestinal toxicity of 5-FU. Paralytic ileus is probably a rare complication of 5-FU and its oral prodrugs, but the oncologist should take
it into careful consideration, because of his possible seriousness and
because a correct management of early signs of abdominal distension
(with nasogastric suction, i.v. infusion of fluids and electrolytes, rectal
tube) can avoid a unnecessary surgical operation
Enhancing sustainability of the railway infrastructure: Trading energy saving and unavailability through efficient switch heating policies
No full textRailway is currently envisioned as the most promising transportation system for both people and freight to reduce atmospheric emission and combat climate change. In this context, ensuring the energy efficiency of the railway systems is paramount in order to sustain their future expandability with minimum carbon footprint. Recent advancements in computing and communication technologies are expected to play a significant role to enable novel integrated control and management strategies in which heterogeneous data is exploited to noticeably increase energy efficiency. In this paper we focus on exploiting the convergence of heterogeneous information to improve energy efficiency of railway systems, in particular on the heating system for the railroad switches, one of the major energy intensive components. To this aim, we define new policies to efficiently manage the heating of these switches exploiting also external information such as weather and forecast data. In order to assess the performance of each strategy, a stochastic model representing the structure and operation of the railroad switch heating system and environmental conditions (both weather profiles and specific failure events) has been developed and exercised in a variety of representative scenarios. The obtained results allow to understand both strengths and limitations of each energy management policy, and serves as a useful support to make the choice of the best technique to employ to save on energy consumption, given the system conditions at hand
On the structural updating using operational responses of a realistic wing model: The ribes test article
No full textThe assessing of the numerical model of a structure to improve its design is of great importance. When referring to the aircraft dynamic properties, a high accuracy numerical model could be achieved if the modal parameters are compared with those characterizing the flying vehicle. In this paper, the updating of the finite element model of a realistic wing model is carried out using the dynamic properties estimated from the analysis of the structure output responses. The experimental modal parameters are used as target characteristics in the structural updating process. The finite element dynamic representation of the wing model, designed and manufactured in order to replicate a typical metallic wing box structure, has been improved by tuning the most sensitive structural parameters
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