Our increasing dependence on complex and critical information infrastructures and the emerging threat of sophisticated attacks, ask for extended efforts to ensure the correctness and security of these systems. Byzantine fault-tolerant state-machine replication (BFT-SMR) provides a way to harden such systems. It ensures that they maintain correctness and availability in an application-agnostic way, provided that the replication protocol is correct and at least \(n-f\) out of n replicas survive arbitrary faults. This paper presents Velisarios, a logic-of-events based framework implemented in Coq, which we developed to implement and reason about BFT-SMR protocols. As a case study, we present the first machine-checked proof of a crucial safety property of an implementation of the area’s reference protocol: PBFT.

The paper presents two approaches in assessing the business continuity management (BCM) attitudes in the organizational context: qualitative and quantitative. The first approach - case study analysis is based on a series of in-depth interviews with the key people involved in the BCM processes in Croatia (Chief Information Officers – CIOs, Chief Executive Officers – CEOs and BC managers). The second approach is an empirical research that was conducted among companies in Bosnia and Herzegovina based on Confirmative Factor Analysis (CFA) which is used for psychometrically validation of the measurement scale of BCP and Structural Equation Modeling (SEM) and t-test for the hypotheses testing. The empirical research has shown that there is a statistically significant difference in terms of attitudes of respondents regarding business continuity depending of companies' size and sector that company belongs to. Specifically, financial sector is in all of BCM segments more coherent than other sectors.In addition, qualitative research revealed the results showing that business continuity plan (BCP) and disaster recovery plan (DRP) were the only IT governance areas that were implemented in business practice. The reason for that may be found in the fact that BCP and DRP are very expensive to implement especially for small companies.

A bstractWe provide an ultraviolet (UV) complete model for the R(D(∗)) anomalies, in which the additional contribution to semi-tauonic b → c transitions arises from decay to a right-handed sterile neutrino via exchange of a TeV-scale SU(2)L singlet W′. The model is based on an extension of the Standard Model (SM) hypercharge group, U(1)Y , to the SU(2)V × U(1)′ gauge group, containing several pairs of heavy vector-like fermions. We present a comprehensive phenomenological survey of the model, ranging from the low-energy flavor physics, direct searches at the LHC, to neutrino physics and cosmology. We show that, while the W′ and Z′-induced constraints are important, it is possible to find parameter space naturally consistent with all the available data. The sterile neutrino sector also offers rich phenomenology, including possibilities for measurable dark radiation, gamma ray signals, and displaced decays at colliders.

This paper presents the method of creating Expert system for decision support on the Android platform. The system knowledge base for the given area of expertise is generated by inductive learning methods based on examples from the WEKA data research system. The system was realized using the Expert System shell for the e2gDroid lite mobile device, based on the application area and a set of training examples, specifically based on the Covertype Data Set qualification problem.