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Mili, Ali

Publications and source records attributed to Mili, Ali.

Quantifying Availability in SCADA Environments Using the Cyber Security Metric MFC

Supervisory Control and Data Acquisition (SCADA) systems are distributed networks dispersed over large geographic areas that aim to monitor and control industrial processes from remote areas and/or a centralized location. They are used in the management of critical infrastructures such as electric power generation, transmission and distribution, water and sewage, manufacturing/industrial manufacturing as well as oil and gas production. The availability of SCADA systems is tantamount to assuring safety, security and profitability. SCADA systems are the backbone of the national cyber-physical critical infrastructure. Herein, we explore the definition and quantification of an econometric measure of availability, as it applies to SCADA systems; our metric is a specialization of the generic measure of mean failure cost.

Availability↗

Quantifying the Impact of Unavailability in Cyber-Physical Environments

The Supervisory Control and Data Acquisition (SCADA) system discussed in this work manages a distributed control network for the Tunisian Electric & Gas Utility. The network is dispersed over a large geographic area that monitors and controls the flow of electricity/gas from both remote and centralized locations. The availability of the SCADA system in this context is critical to ensuring the uninterrupted delivery of energy, including safety, security, continuity of operations and revenue. Such SCADA systems are the backbone of national critical cyber-physical infrastructures. Herein, we propose adapting the Mean Failure Cost (MFC) metric for quantifying the cost of unavailability. This new metric combines the classic availability formulation with MFC. The resulting metric, so-called Econometric Availability (EA), offers a computational basis to evaluate a system in terms of the gain/loss ($/hour of operation) that affects each stakeholder due to unavailability.

Availability↗

Modeling the Fault Tolerant Capability of a Flight Control System: An Exercise in SCR Specification

In life-critical and mission-critical applications, it is important to make provisions for a wide range of contingencies, by providing means for fault tolerance. In this paper, we discuss the specification of a flight control system that is fault tolerant with respect to sensor faults. Redundancy is provided by analytical relations that hold between sensor readings; depending on the conditions, this redundancy can be used to detect, identify and accommodate sensor faults.

Alexander, Chris↗