Géza Szabó

Automatic Fault-Tree Generation as a Support for Safety Studies of Railway Interlocking Systems

Abstract In the paper, the safety analysis of the state-of-the-art computer based railway interlocking systems is discussed. The fault-tree analysis is selected as a primary method to evaluate the failure behavior of the system. Since the hardware system and the functional tasks of the modern interlocking systems can be very complicated, automatic fault-tree generation is introduced, which provides faster analysis and models without human errors.

Practical treatment-methods for adaptive components in the fault-tree analysis

In this paper, the dependability analysis of functionally reconfigurable logic is discussed. Such logic can change its function if a failure has occurred and it has been detected. Based on the fault tree technique, several methods are illustrated and investigated, namely the macro-models, the Markov chains, and the multi-static models, which provide the treatment of the system components with adaptive properties. This paper also proposes a multi-state based procedure well fitted to the re-configuration. Closed formulas are applied in this procedure, as they ensure simpler and faster analysis for a class of systems than other procedures.

Potential Gains of Reactive Video QoE Enhancement by App Agnostic QoE Deduction

We propose an app agnostic QoE deduction method that can be used for on-line traffic prioritization. Our implemented method extracts QoE information directly from the screen of mobile devices and this information is utilized for video traffic prioritization to improve user QoE. We evaluate our method and show that it can realize 80-100% of the achievable gain of the state-of-the- art methods with 50% less traffic that needs to be prioritized to achieve this. We provide deployment alternatives for traffic prioritization and evaluate performance impact on achievable gain.

Status and actual risk monitoring in a NPP reactor protection system

The paper introduces a risk monitoring solution for a NPP protection system. The two main functions of the solution, the Status Monitoring System and the Risk Monitoring System are described, as well as the possible improvements to enhance system performance and shorten the response time.