Search results for "block"

Ballasted Track Superstructures: Performance of Innovative Railway Sleepers

2012

A railway sleeper is the structural element which transversally connects the two rails by means of fastening components, thus ensuring its gauge. Its additional function is to firmly secure the track to the ballast and to distribute the loads transferred from railway carriages to the ballast. One of the most important parameters in the characterization of performance given by railway sleepers is represented by their lateral resistance to the sliding: the higher its value increases, the better the track stability becomes, thus reducing the frequency of maintenance interventions necessary to keep the superstructure efficient. This article focuses on the performance of two innovative railway s…

Beta-Blocker Use in Older Hospitalized Patients Affected by Heart Failure and Chronic Obstructive Pulmonary Disease: An Italian Survey From the REPOS…

2022

Beta (β)-blockers (BB) are useful in reducing morbidity and mortality in patients with heart failure (HF) and concomitant chronic obstructive pulmonary disease (COPD). Nevertheless, the use of BBs could induce bronchoconstriction due to β2-blockade. For this reason, both the ESC and GOLD guidelines strongly suggest the use of selective β1-BB in patients with HF and COPD. However, low adherence to guidelines was observed in multiple clinical settings. The aim of the study was to investigate the BBs use in older patients affected by HF and COPD, recorded in the REPOSI register. Of 942 patients affected by HF, 47.1% were treated with BBs. The use of BBs was significantly lower in patients with…

Atti del convegno Comunicazione di sostenibilità e blockchain Strumenti giuridici e prospettive tecnologicheperilsettorevitivinicolo

2022

On GPU-accelerated fast direct solvers and their applications in image denoising

2015

A note about 2-(v,5,lambda) designs

2010

Magma and volatile supply to post-collapse volcanism and block resurgence in Siwi caldera (Tanna Island, Vanuatu arc)

2011

Siwi caldera, in the Vanuatu arc (Tanna island), is a rare volcanic complex where both persistent eruptive activity (Yasur volcano) and rapid block resurgence (Yenkahe horst) can be investigated simultaneously during a post-caldera stage. Here we provide new constraints on the feeding system of this volcanic complex, based on a detailed study of the petrology, geochemistry and volatile content of Yasur-Siwi bulk-rocks and melt inclusions, combined with measurements of the chemical composition and mass fluxes of Yasur volcanic gases. Major and trace element analyses of Yasur-Siwi volcanic rocks, together with literature data for other volcanic centers, point to a single magmatic series and p…

A System-based View of Blockchain Governance

2023

Abstract CONTEXT Governance is crucial in achieving the success and sustainability of blockchain systems. However, blockchain governance is multi-faceted, complex, dynamic, and challenging due to its decentralized nature and automatically enforced rules and mechanisms. OBJECTIVES This study aims to advance the theory of blockchain governance and support practitioners to deepen the researchers’ and practitioners’ understanding of blockchain governance. METHODS The study is a systematic literature review of 75 articles that applies systems theory to conceptualize blockchain governance as a system and parsimoniously organize its interrelated elements into a conceptual model. RESULTS The paper …

New techs, new threats: sfide e opportunità della rivoluzione blockchain

2021

Considering the current diffusion of blockchain technology in the most different fields, ranging from public governance to economics, from contractual applications to health, the contribution addresses the issue of the legal regulation of this new technology, precisely because of its vast applications. From the comparison between the European model and the American one, the approach of the European legislator ‒ despite the delay with which the institutions have addressed the issue, seems to show, as already happened in other areas, a more 'social oriented' perspective and based on a sort of 'democratization' of data compared to the American approach, more ‘business oriented’, where the scho…

DLT, BLOCKCHAIN E SMART CONTRACT

2020

La tecnologia blockchain nasce nel 2008 con l’annuncio di BitCoin [1], una delle più diffuse criptovalute. Il ruolo fondamentale della blockchain nell’ambito delle criptovalute è quello di garantire l’impossibilità di spendere due volte lo stesso valore in transazioni successive, fattispecie che viene indicata nel mondo anglosassone come double spending. Il problema del double spending è di difficile soluzione quando l’informazione di un valore è espressa in formato digitale, il quale ben si presta alla riproduzione di copie identiche consentendo quindi di spendere quel valore più volte. Il problema è superabile in presenza di una entità centralizzata fidata, quale ad esempio una banca, ma …

Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain

2017

In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate) of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new blo…