SSARS 2008 VOL 2

Jurdziński Miroslaw, Kołowrocki Krzysztof, Soszyńska Joanna
An approach to ship operation analysis with primary application to “Stena Baltica” ferry operating at Baltic Sea
The paper deals with a general model of shipping process at restricted and coastal water areas. The simplified defining of restricted water areas and open water areas is performed and the influence of the environmental and infrastructure effects on the ship operation processes in these water areas is discussed. A general semi-markov model of a system operation process is proposed and the methods of its parameters statistical identification are presented. Further, the ferry operating at Baltic Sea operation process is analyzed and its operation states are defined. A preliminary collection of statistical data necessary to the ferry operation process identification is included.[full text]

Kołowrocki Krzysztof
Reliability and risk analysis of multi-state systems with degrading
Applications of multi-state approach to the reliability evaluation of systems composed of independent components are considered. The main emphasis is on multi-state systems with degrading components because of the importance of such an approach in safety analysis, assessment and prediction, and analysing the effectiveness of operation processes of real technical systems. The results concerned with multi-state series systems are applied to the reliability evaluation and risk function determination of a homogeneous bus transportation system. Results on homogeneous multi-state “m out of n” systems are applied to durability evaluation of a steel rope. A non-homogeneous series-parallel pipeline system composed of several lines of multi-state pipe segments is estimated as well. Moreover, the reliability evaluation of the model homogeneous multi-state parallel-series electrical energy distribution system is performed.[full text]

Kołowrocki Krzysztof, Kwiatuszewska-Sarnecka Bożena, Soszyńska Joanna
Modelling of operational processes of port bulk cargo transportation system
In the paper a general analytical model of industrial systems environment and infrastructure influence on their operation processes is constructed. Next, as its particular case a detailed model of port environment and infrastructure influence on port transportation systems operation processes is obtained to apply and test it to selected transportation systems used in Gdynia Port.

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Kołowrocki Krzysztof, Soszyńska Joanna
A general model of industrial systems operation processes related to their environment and infrastructure
The operation process of the complex industrial system is considered and its operation states are introduced. The semi-markov process is used to construct a general probabilistic model of the considered complex industrial system operation process. To build this model the vector of probabilities of the system operation process initials operation states, the matrix of probabilities of the system operation process transitions between the operation states, the matrix of conditional distribution functions and the matrix of conditional density functions of the system operation process conditional sojourn times in the operation states are defined. To describe the system operation process conditional sojourn times in the particular operation states the uniform distribution, the triangle distribution, the double trapezium distribution, the exponential distribution, the Weibull distribution and the normal distribution are suggested. Under these all assumptions from the constructed general model the main characteristics of the system operation process are find. The mean values of the system operation process conditional sojourn times in particular operation states having these distributions are calculated. Moreover, the unconditional distribution functions of the system operation process unconditional sojourn times in the particular operation states, the mean values of the system operation process unconditional sojourn times in the particular operation states, the limit values of the transient probabilities of the system operation process at the particular operation states and the mean values of the system operation process total sojourn times in the particular operation states are determined. [full text]

Kołowrocki Krzysztof, Soszyńska Joanna, Xie Min, Kien Ming Ng, Salahuddin Mohamed
Safety and reliability of complex industrial systems and process
Poland-Singapore Joint Project
The project aims mainly to propose new and to develop existing methods, tools and software capable of supporting intelligent modelling and decision support systems, in controlling and optimising the safety and reliability of complex real industrial systems and processes, with their primarily applications in the maritime transportation sectors. Its main focus is on the use of new safety and reliability analysis techniques to improve and optimise safety and reliability of complex real industrial systems related to their operation processes. It will look into the design of industrial systems and development of new methods and the employment of new theoretical results that are applicable to designing and safety and reliability evaluations as well as the improvements of real complex industrial systems and processes. [full text]
Łebkowski Andrzej, Dziedzicki Krzysztof
Agent system in control of ship movement
The problem of determining the optimal passing route of the ship between its current position and a remote destination point including the navigation situation occurring during moving along the route has been a subject of many papers and so far has not been definitely solved. In order to determine an optimal and safe route of the ship and its control along it, the author suggests application of an agent system. In the presented agent system three goals are accomplished. The first relies on data acquisition about current navigation situation around the ship and on analysis of possible collision risk. Second target – so far not present in anti-collision systems – relies on automatic negotiations between ships that operate in the same water region or between the coast stations in order to determine the potential area thru which a passing route could have been set. The third one connected to determining the passing route and its autocorrecting depending on current navigation situation. [full text]

Mennis Evangelos, Dagkinis Ioannis, Nikitas Nikitakos, Platis Agapios

Modelling ship’s diesel electrical system using Markov theory

One of the most critical systems for a ship operation is the diesel generator set. This is why the ship preserves four different diesel generators except the power battery packs. The paper describes the generator operation and the main failure conditions. Assuming that the failure rate of the system parts is constant the paper shows how the diesel generator system could be modelled in the context of Markov theory. [full text]

Milazzo Maria Francesca, Maschio Giuseppe, Uguccioni Giovanni
Frequencies assessment of loss containment including the effects of measures of risk prevention and mitigation
The question of how the effects of management and organisational variables can be incorporated into assessment of frequency of loss containment events is currently of considerable interest. Usually these typology of events arises from an uncontrolled accidental phenomena or a combination of active and latent human errors in areas such as design, operations and maintenance. In the 2006 a development of a methodology for the quantification of the effects of measures of risk prevention or mitigation on the frequencies of rupture of pipework has been presented, the approach is based on the methodology proposed by Papazoglou in 1999. Taking advantage of Papazoglou methodology the estimation of these effects has been achieved through the definition of the links between the failure causes that are the origin of incidents and the measures adopted by the company in order to prevent and/or to mitigate them. After an overview on the failure causes in piping, the aim of this paper is to present the application of the recent modified methodology.[full text]

Nedbálek Jakub
Neural networks for function approximation in dynamic modelling
The paper demonstrates the comparsion of Monte Carlo simulation (MC) algorithm with the Radial Basis Function (RBF) neural network enhancement of the same algorithm in the reliability case study. In our test, we dispose of the tank containing liquid water – its temperature process variable evolves deterministicly according to the differential equation, which solution is known. All component failures are considered as a stochastic events. In the case of surpassing temperature treshhold of the liquid inside the tank, we interpret the situation as the system failure. With regard to process dynamics, we attempt to evaluate the tank system unreliability related to the initiative input parameters setting. The neural network is used in equation coeficients calculation, which is executed in each transient state. Due to the neural networks, for some of the initial component settings, we can achieve the results of computation faster than in classical way of coeficients calculating and substituting into the equation.[full text]

Nowakowski Tomasz, Werbińska Sylwia
Maintenance modelling concepts – state of art
We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models: the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of two-unit system maintenance process is provided in order to compare various maintenance policies.[full text]

Okulewicz Józef, Salamonowicz Tadeusz
Preventive maintenance with imperfect repairs of a system with redundant objects
An object ability to realise tasks may be restored by repairing only failed components. This is called imperfect repair as the object is not as good as new after such a repair. Preventive replacement is an example of imperfect repair as well. The advantage of such maintenance is that it enables controlling a reliability level of a system. Sets of objects’ components which should be replaced are derived on a basis of statistical diagnosing with use of data about components failures. The acceptable level of a failure risk while executing transportation tasks has been taken as a criterion of choosing elements to be replaced. An algorithm of selecting components for preventive replacement has been developed. It was shown that a level of a system reliability can be controlled by changing an order of a quantile function in coordination and a number of redundant objects. A computer simulation model of the system was used to illustrate derived dependencies.[full text]

Pantanali Claudio, Bianco Cristina, Gioacchino Nardin, Meneghetti Antonella, Lirussi Marco
Risk analysis by threshold evaluation (RATE): a new approach to OHS in small and medium enterprises
Traditional risk assessment methodologies have been thought for large enterprises and they are not easy to handle by small and medium enterprises (SMEs): that can hardly assign resources to safety analysis. However, occupational health and safety is even more important in SMEs since their core competencies are based on skilled manpower. Attempting to solve this problem, a new methodological approach was developed: RATE (Risk Analysis by Threshold Evaluation) is a “bottom up” method which allows safety analysts to follow a standard path, not much time-spending due to a semi-probabilistic approach and enabling identification of hidden risks. RATE perspective is centred on recognising risks for workers rather than machine ways of failure. It is aimed to help entrepreneurs to assess the capacity of their system to reach a desired safety level and to what extent safety measures can improve safety performance.[full text]

Pérez-Ocón Rafael, Montoro-Cazorla Delia, Segovia M. Carmen
Shock models under policy N
We present the life distribution of a device subject to shocks governed by phase-type distributions. The probability of failures after shock follows discrete phase-type distribution. Lifetimes between shocks are affected by the number of cumulated shocks and they follow continuous phase-type distributions. The device can support a maximum of N shocks. We calculate the distribution of the lifetime of the device and illustrate the calculations by means of a numerical application. Computational aspects are introduced. This model extends other previously considered in the literature.[full text]

Pham Hoang
Surprises: The warranty, the reliability, and the systemability
In the fast growing, competitive global market and dynamic environments, we not only depend upon the continued functioning of a wide array of complex machinery and equipment of our everyday safety, security, mobility and economic welfare but also expect our electric appliances, automobile, transportation stations and data exchange systems to perform and perform well wherever and whenever we need them in order to survive. Such expectation is seldom realistic since it eventually breaks down, particularly when the system (or product) nowadays is operating in a complex random operating environment. Strong warranties are becoming more useful tactics for developers to attract potential customers especially due to the slowing economy. This talk discusses the research challenges and trends, and the reflections of the perception between the warranty, the reliability and the systemability.[full text]

Plewa Marcin
Assessment of products’ reliability influence on remanufacturing processes

Remanufacturing is a process of recapturing value from returned products. Whole products are brought back to like-new condition. The seven factors, that make production planning and process control for remanufacturing more complicated then equivalent activities in normal manufacturing, had been proposed in literature. The main one is the uncertain timing and quantity of returns. There is a lack of reliability based forecasting models to better predict products life-cycles, return rates and quantities. Only one reliability based production planning method for remanufacturing had been proposed. It identifies two return reasons and it is appropriate only for single-use products. In practice most of products are serviced and return only in specific cases. In this article seven different return reasons has been identified and third one has been investigated. Other will be studied in future papers. [full text]


Romano Alfredo, Perrone Francesco
Review of an insurance policy of a directive Seveso III industrial activity by using risk analysis. An example
The purpose of this article is to demonstrate that risk analysis for major hazard plants [1] is a necessary instrument for the evaluation of consequences and damages outside the plants. The MPL (Maximum Possible Loss), i.e. the scenario with the highest damage distances, is the basic parameter to evaluate the external damages. The threshold values, related to the magnitudo of the accidental scenarios are in accordance with an Italian decree (May 9th, 2001). The disability percentage has been identified for each type of damage assessed. The number of people involved directly or indirectly in the accidental scenario has been evaluated, according to the previous criteria. The impact of the accidental scenario effects outside the plant fence has been evaluated too. The biological damage, the moral damage and the income reduction damage have been evaluated. The present methodology is able to evaluate the effects, generated by the major hazard plants, that can involve people and/or assets outside the plant fence.[full text]

Romano Alfredo, Perrone Francesco, Torretta Vincenzo
New aspects about territorial planning
The purpose of the present paper is to show that the actual Italian Law for the territorial planning (D.M. 09/05/2001 [3]) could be reviewed by considering domino effects generated by industrial companies related to Major Accidental Hazard Directive on industrial companies which Major Accidental Hazard Directive is not applicable. These effects can involve directly vulnerable elements. An example has been considered in the paper, by identifying an industrial company related to Major Accidental Hazard Directive which accidental scenarios involve an other industrial company, not related to Major Accidental Hazard Directive. Two configuration have been identified: 1) territorial planning by considering only the effects generated by the industrial company related to Major Accidental Hazard Directive and 2) territorial planning by considering domino effects. The latter configuration has generated damages on residential areas that haven’t been involved by configuration 1). The accidental scenarios have been evaluated in terms of heat radiation and dangerous liquid penetration in the soil.[full text]

Smalko Zbigniew
Terratechnology characteristics of technical system
The subject of this paper deals with dependability of machine systems base on selected usable characteristics. In the subsystem man-machine and environment, determined tasks are carried out. The sequence of activity is following: man handles machine, which in turn makes the environment deliver desired reaction, e.g. processing or transportation. A machine and desired reaction of environment will recognize the positive effect of above activities as carrying out of set task. It is also of utmost importance that the man and machine’s impact on environment is efficient and harmless. Therefore the selection of an adequate machine and its operator to carry out the given task is crucial. The circumstances considered as undesired for task implementation are identified as hazard to man and machine. Within the endangered man – machine and environment subsystem, we can distinguish following phases in the machine degradation process: worthy, partially worthy, partially unworthy, critically unworthy and totally unworthy. The selection of adequate means towards achieving set goals is considered important, and, subsequently, the description of selected machine and human (as operator and decision maker) attributes has been undertaken. The basic attributes of man and machine complex are: adequacy, dependability, safety, durability and effectiveness. Adequacy, described as common machine property, turns out to be a collection of four attributes: functionality, configurability, coverage, and programmability. Reliability, on closer inspection, as a combined property of man – machine complex, is described by four attributes: reliability, redundancy, faultlessness and availability. Safety, as a man – machine – environment property is described by a collection of five attributes: protectionability, hazardousness, harmlessness, safeguardability and deteriousness. Durability as a machine property can be described by five attributes: strength, refractoriness, maintainability, supportability and serviceability. Effectiveness as a man – machine system property is described by four attributes: efficiency, capability, economically and managementability. It is acceptable to assume that the attributes mentioned above can be of use when selecting machines for outdoor exploitation and facilitating of selected tasks. Particular significance is in the relations between basic attributes of the man – machine – environment subsystem, namely: dependability is the starting point for safety and effectiveness, durability assures dependability, safety and effectiveness, adequacy guarantees a successful outcome of all named attributes of man – machine system.[full text]

Soszyńska Joanna
Asymptotic approach to reliability evaluation of large “m out of l”- series system in variable operation conditions
The semi-markov model of the system operation process is proposed and its selected parameters are defined. There are found reliability and risk characteristics of the multi-state “m out of ”-series system. Next, the joint model of the semi-markov system operation process and the considered multi-state system reliability and risk is constructed. The asymptotic approach to reliability and risk evaluation of this system in its operation process is proposed as well. [full text]

Tanguy Christian
Asymptotic dependence of average failure rate and MTTF for a recursive, meshed network architecture
The paper is concerned with the exact and asymptotic calculations of the availability, average failure rate and MTTF (Mean Time To Failure) for a recursive, meshed architecture proposed by Beichelt and Spross. It shows that the asymptotic size dependences of average failure rate and MTTF are different, but not inverse of each other, as is unfortunately assumed too frequently. Besides, the asymptotic limit is reached for rather small networks.[full text]

Valis David
Contribution to failure description
In our lives we meet many events which have very diverse causes, mechanisms of development and consequences. We frequently work with the events´ description besides other assessments in safety/risk assessment. In pure technical applications these events are related with the failure occurrence of equipment, a device, a system or an item. The theory speaks about failure itself, its mechanisms, circumstances of occurrence, etc. but at the same time we need appropriate terminology to describe these conditions. Our basic approaches into observing, dealing and handling failure may fall into two groups. We either talk about a probabilistic approach or about a deterministic (logic) approach. As we need to get some information about a failure we need to find it or transfer it from different sources. This contribution can be a complex problem for the term “failure” and its related characteristics. In the paper there are mentioned functions of an object and their description, classification of failures, main characteristics of failure, possible causes of failure, mechanisms of failure and consequences of failure and also other contributions related with failure very closely. [full text]

Valis David, Koucky Miroslav
Contribution to availability assessment of complex systems
As we use complex systems with one shot items in many technical applications we need to know basic characteristics of such system. Performance, safety and other are as much important as dependability measures. In real applications we have to take into account a related distribution of an observed variable. In terms of complex systems with one shot items it is a discrete random variable related to one shot item. The whole system and its failures (unexpected and inadvertent events) may have two typical types of distributions and their characteristics. We either consider a continuous variable (such as time, mileage, etc.) or a counting variable (such as number of cycles, sequences, etc.) regarding to a failure occurrence. As the one shot items is supposed to back up the main system function the total reliability of the system should be higher than. The main issue regarding the system using one shot items in their construction is to determine the probability of the task (mission) success. The paper presents both theoretical approach and practical example of the solution.[full text]

Zając Mateusz, Budny Tymoteusz

On determinations of some characteristics of semi – Markov process for different distributions of transient probabilities
There is model of transport system presented in the paper. The opportunities of semi – Markov process definition are included. The system is defined by semi –Markov processes, while functions distributions are assumed. There are attempts to assess factors for other than exponential functions distributions. The paper consist discussion on Weibull and Gamma distribution in semi – Markov calculations. It appears that some forms of distribution functions makes computations extremely difficult. [full text]

Zhao Xuejing, Fouladirad Mitra, Bérenguer Christophe, Bordes Laurent

Maintenance Policy for deteriorating system with explanatory variables
This paper discusses the problem of the optimization of maintenance threshold and inspection period for a continuously deteriorating system with the influence of covariates. The deterioration is modeled by an increasing stochastic process. The process of covariates is assumed to be a temporally homogeneous finite-state Markov chain. A model similar to the proportional hazards model is used to represent the influence of the covariates. We derive the optimal maintenance threshold and optimal inspection interval to minimize the expected average cost. Comparisons of the expected average costs under different conditions of covariates and different maintenance policies are given by numerical results of Monte Carlo simulation. [full text]