Ancione Giuseppa, Milazzo Maria Francesca, Salzano Ernesto, Maschio Giuseppe
Semi-automatic geo-processing procedure for the vulnerability mapping of industrial facilities in areas with the potential volcanic ash fallout
Following recent severe natural events, attention has been focused on industrial installations located in areas prone to natural hazards. This work concerns the study of volcanic Na-Tech events (i.e. technological risks triggered by natural causes) and aims at defining a procedure for the representation of the vulnerability of industrial facilities in areas with the potential volcanic ash fallout by means a Geographical Information System (GIS). Here, we focused on the construction of a semi-automatic procedure for the vulnerability mapping for cases where input data is very limited; it is based on the use of a specific tool named ModelBuilder of the ArcGIS software.[full text]
Berg Heinz Peter, Fritze Nicole
Reliability and vulnerability of critical infrastructure – Electricity distribution
In recent years the failure frequency of transformers increased. In particular fires and explosions of main oilfilled transformers are considered as critical. Therefore, international experiences of transformer failures at nuclear and non-nuclear power plants and at substations have been investigated in more detail. Consequences of transformer failures with respect to a reliable electric power supply and distribution are addressed and proactive measures to enhance the reliability of critical infrastructure and to avoid blackouts are described.[full text]
Diagkinis Ioannis, Nikitakos Nikitas
Application of analytic hierarchy process and TOPSIS methodology on ships’ maintenance strategies
The aim in adoption of maritime equipments’ maintenance strategy is the reduction of risk in order to achieve safer navigation, to enhance environmental friendly behaviors, to increase the safety and positively contribute to the overall operability management of the ship. The use of weak maintenance strategy could result in waste of time, money and resources, and often has no effect on improving or maintaining the availability of equipments.
In this article, we propose a model in evaluation of on non-deterministic factors that affect the ships’ safety and a framework for ships management governance. The review of maintenance strategies has proven that a decision support mechanism needs mainly multiple criteria decision on ship equipments maintenance strategy selection. Through Analytic Hierarchy Process methodology and the extended evaluation of results on adoption of Technique for Order Preference by Similarity to Ideal Solution a useful tool to prioritize needs at any level and includes the decisions that should be taken into consideration from the shore office managers and the ship personnel for the safe functionality of the ship is provided.
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Duarte José Caldeira, Craveiro João Taborda
An optimal preventive maintenance policy of parallel-series systems
This paper presents an algorithm to solve the problem of maintenance management of a two state parallel-series system based on preventive maintenance over the different system components. It is assumed that all components of the system exhibit Weibull hazard function and constant repair rate and that preventive maintenance would bring the system to the as good as new condition. The algorithm calculates the interval of time between preventive maintenance tasks for each component, minimizing the costs, and in such a way that the total downtime, in a certain period of time, does not exceed a predetermined value. It is presented an industrial case study where the algorithm is applied. [full text]
Jodejko-Pietruczuk Anna, Nowakowski Tomasz, Werbińska-Wojciechowska Sylwia
Time between inspections optimization for technical object with time delay
In the presented paper, authors are concerned with a single-element system liable to costly failure. Failure is taken here to mean a breakdown or catastrophic event, after which the system is unusable until repaired or replaced. The mathematical modelling of maintenance decisions for such a system is provided with the use of delay-time and delay-time analysis. The directions for further research work are defined.
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Kisezauskiene Lina, Vaidogas Egidijus Rytas
Risk to built property posed by transportation of liquid gasses
An assessment of risk posed by a road transportation of liquefied gases to roadside property is considered. The attention is focused on an estimation of the probability of thermal damage to a roadside object. Such damage can be caused by a boiling-liquid expanding-vapour explosion (BLEVE) of a road tank. It is suggested to estimate this probability by a combined application of stochastic simulation and deterministic models used to predict a thermal effect of a BLEVE fireball. A development of a fragility function expressing the probability of ignition of the roadside object is discussed. The fragility function is integrated into the simulation-based procedure of an estimation of the thermal damage probability. The approach proposed in this study is illustrated by an example which considers an assessment of thermal damage to a reservoir built in the vicinity of a road used for transportation of liquefied gases. [full text]
Kołowrocki Krzysztof
Safety of critical infrastructures
The paper presents a general approach to safety analysis of critical infrastructures that aims to suggest new and to develop existing methods and tools capable of supporting intelligent modeling and decision making in controlling and optimizing the safety of those systems and their accidents consequences risk. Its main focus is on the suggestions of the creation and usage of new techniques, procedures and strategies to improve and to optimize safety of real complex infrastructure systems related to the inside dependencies – among their subsystems and components and the outside dependencies – coming from their operation environment and from other dangerous events and natural hazards. The approach tries to create an original and coherent methodology of safety of critical infrastructures useful in ensuring and improving safety of those systems in various industrial sectors by providing an integrated package of solutions consisting of various packages of theoretical and practical tools ready for direct use by safety theoreticians and practitioners dealing with safety of real critical infrastructures.
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Kołowrocki Krzysztof, Kuligowska Ewa,
Monte Carlo simulation application to reliability evaluation of port grain transportation system operating at variable conditions
This paper presents the Monte Carlo simulation technique applied to the reliability evaluation of systems related to the variable operation conditions. A semi-Markov processes is applied to construct the system operation model and its main characteristics are determined. The method of linking this model with the systems reliability is proposed to get a general reliability model of the complex system operating at the variable conditions. An application of the proposed Monte Carlo simulation based on this method is illustrated in the reliability evaluation of a port grain transportation system. This way obtained results are compared with the results achieved by analytical way. [full text]

Kosmowski Kazimierz
Problems in designing and operating functional safety solutions of higher integrity levels
The aim of this article is to identify and discuss some problems that have been encountered in designing and operating the functional safety solutions of higher safety integrity levels (SIL 3 and SIL 4) in the light of analyses outlined in a new version of the international standard IEC 61508:2010. Examples of such solutions are the electric / electronic / programmable electronic systems (E/E/PESs) and the safety instrumented systems (SISs) being designed and operated respectively according to IEC 61508 and IEC 61511 in the system safety life cycle. The role of functional safety solutions is effective reducing and controlling the individual and/or societal risk with regard to tolerable levels defined. Some aspects of potential influence of danger failures of the E/E/PESs or SISs on the plant safety are considered. The influence of common cause failures (CCFs) and dependent failures in the context of the layer of protection analysis is also discussed. [full text]

Montewka Jakub, Goerlandt Floris, Kujala Pentti
On a risk perspective for maritime domain
In the maritime domain, the risk is evaluated within the framework of Formal Safety Assessment (FSA), introduced by International Maritime Organization in 2002. Although the FSA has become internationally recognized and recommended method, the definition, which is adopted there, to describe the risk, seems to be too narrow to reflect properly the actual content of the FSA. Therefore this article discusses methodological requirements for the risk perspective, which is appropriate for risk management in the maritime domain with the special attention to maritime transportation systems (MTS). This perspective considers risk as a set encompassing the following: the set of plausible scenarios leading to an accident, the likelihoods of the unwanted events within the scenarios and the consequences of the events. These elements are conditional upon the available knowledge about the analyzed system, and understanding of the system behaviour, therefore these two are inherent parts of risk analysis, and need to be included in the risk description. [full text]

Soszyńska-Budny Joanna
Modelling safety of multistate systems with ageing components

Basic notions of the ageing multistate systems safety analysis are introduced. The system components and the system multistate safety functions are defined. The mean values and variances of the multistate systems lifetimes in the safety state subsets and the mean values of their lifetimes in the particular safety states are defined. The multi-state system risk function and the moment of exceeding by the system the critical safety state are introduced. The exemplary safety structures of the multistate systems with ageing components are defined and their safety functions are determined. As a particular case, the safety functions of the considered multistate systems composed of components having exponential safety functions are determined. Applications of the proposed multistate system safety models to the evaluation and prediction of the safty characteristics of the exemplary series, parallel, “m out of n”, consecutive “m out of n: F”, series-parallel, parallel-series and “m out of l”-series systems are presented as well.[full text]

Sugier Jarosław
Low-cost hardware implementations of Salsa20 stream cipher in programmable devices
Salsa20 is a 256-bit stream cipher that has been proposed to eSTREAM, ECRYPT Stream Cipher Project, and is considered to be one of the most secure and relatively fastest proposals. This paper describes hardware implementation of various architectures of this cipher in popular Field Programmable Gate Arrays (FPGA). The implemented architectures are based on the loop-unrolled data flow organization and after pipelining they can reach the throughput in the range of 20 – 30 Gbps even after fully automatic implementation in popular low-cost families of Spartan-3 and Spartan-6 from Xilinx. More resource-limited iterative architectures achieve speed of 1 – 2 Gbps. The results that are included in this work present potential of the algorithm when it is implemented in a specific FPGA environment and provide some information for evaluation of cipher effectiveness in contemporary popular programmable devices. [full text]

Tchórzewska-Cieślak Barbara, Pietrucha-Urbanik Katarzyna
Failure risk analysis in the collective water supply systems in crisis situations

Risk is a basic category to estimate water supply system safety. The first step in risk assessment is to identify the threats and their possible consequences. One of methods for risk assessment is the method using the socalled risk graphs. It relies on the preliminary analysis of such risk factors as: the frequency of threat occurrence – F, the duration of the risk exposure – E, the size of the possible consequences – C and a degree of protection – O, that is inversely proportional to the mentioned measures of risk. The route along the branches of the risk graph should be started from the determination of the initiating/peak event which is the undesirable event (e.g. secondary water contamination in water-pipe network). The expanded risk graph presented in the work differs from the standard (commonly used) graph because it takes into consideration all combinations of the particular risk factors.[full text]