- Lithuanian Energy Institute, Laboratory of Nuclear Installation Safety, Department Memberadd
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- Kaunas University of Technology, Faculty of Mathematics and Natural Sciences, Professoredit
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ABSTRACT The probability-based approach that integrates deterministic and probabilistic methods was developed to analyse failures of NPP buildings and components. This methodology was applied to safety analysis of the Ignalina NPP. The... more
ABSTRACT The probability-based approach that integrates deterministic and probabilistic methods was developed to analyse failures of NPP buildings and components. This methodology was applied to safety analysis of the Ignalina NPP. The application of this methodology to two postulated accidents―pipe whip impact and aircraft crash―is presented in this chapter. The NEPTUNE software system was used for the deterministic transient analysis of the pipe whip impact and aircraft crash accidents. Many deterministic analyses were performed using different values of the random variables that were specified by ProFES. All the deterministic results were transferred to the ProFES software system, which then performed probabilistic analyses of piping failure and wall damage.
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Abstract Bayesian models are already present in almost every branch of reliability theory and its applications. This class of models provides an easy and intuitive way to infer about the issue at hand with a clear handling of data... more
Abstract Bayesian models are already present in almost every branch of reliability theory and its applications. This class of models provides an easy and intuitive way to infer about the issue at hand with a clear handling of data uncertainty. It is often the case that data used for the systems reliability assessment come from more than one information source. Whether it is power plants at different geographical locations, gas transmission pipelines operating in different environment or power transmission networks deployed within various areas. Therefore, different operating conditions, varying maintenance programs and efficiencies have their share in influencing the vulnerability and variability of reliability data. However, in practice, it is usually the case that this heterogeneity is neglected leading to the underestimation of underlying uncertainty of the data. Bayesian models are capable of dealing with this kind of uncertainty as opposed to the frequentists’ statistical methods. Hierarchical Bayesian modelling technique provides means to quantify not only within-source, but also between-source uncertainties. Even in the case of small data samples, it performs well, unlike for example the classical likelihood method which may provide degenerate estimates. In this paper, authors investigate the possibility to incorporate this kind of uncertainty into the systems reliability and vulnerability assessment through the Bayesian framework in several cases: instrumentation and control components of nuclear power plants, gas transmission networks and power transmission grids.
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This study represents a framework of expert knowledge incorporation into the machine learning pipeline used for the integrated trade risk assessment process. We review the related literature to reflect the newest risk prediction... more
This study represents a framework of expert knowledge incorporation into the machine learning pipeline used for the integrated trade risk assessment process. We review the related literature to reflect the newest risk prediction methodologies and combinations of multiple approaches, i.e., expert systems, ensemble models application. We integrate expert risk knowledge into the clustering results review process and adjust results based on the risk expert recommendations. Classes confirmed by the expert are further used as labels for the automatic risk assessment process. The framework was tested with the historical data from the trading company, and classification results were evaluated by calculating the F1 score.
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[??????]: ??? The IRIS (International Reactor, Innovative and Secure) is innovative light water reactor with a modular, integral primary system configuration. The IRIS plant has used Safety-by-DesignTM from its inception. The IRIS plant... more
[??????]: ??? The IRIS (International Reactor, Innovative and Secure) is innovative light water reactor with a modular, integral primary system configuration. The IRIS plant has used Safety-by-DesignTM from its inception. The IRIS plant design features such as: compact design, ...
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Analizuojant lėktuvo kritimą, nagrinėjamos atsitiktinės lėktuvų katastrofos, kuomet nevertinami teroristiniai veiksmai ar kita piktybinė žmonių veikla. Statistiškai analizuojamas lėktuvų kritimo ant nagrinėjamų objektų dažnis, pirmiausia... more
Analizuojant lėktuvo kritimą, nagrinėjamos atsitiktinės lėktuvų katastrofos, kuomet nevertinami teroristiniai veiksmai ar kita piktybinė žmonių veikla. Statistiškai analizuojamas lėktuvų kritimo ant nagrinėjamų objektų dažnis, pirmiausia priklauso nuo orlaivių skraidymo intensyvumo šalia tų objektų. Sunkiau statistiškai vertinami tokie lėktuvų avarijas lemiantys veiksniai, kaip techninė lėktuvų būklė, ekipažo patirtis, meteorologinės sąlygos ir kiti veiksniai. Dėl didelio avarijas inicijuojančių veiksnių neapibrėžtumo lėktuvo kritimo modeliavimas paprastai grindžiamas konservatyviomis prielaidomisKauno technologijos universitetasKauno technologijos universitetas, robertas@mail.lei.ltLietuvos energetikos institutasLietuvos energetikos institutas, j.augutis@isag.lei.l
A general framework of a system for early seizure detection and alert is presented. Many studies have shown high potential of electroencephalograms (EEG) when there are used together with machine learning algorithms for... more
A general framework of a system for early seizure detection and alert is presented. Many studies have shown high potential of electroencephalograms (EEG) when there are used together with machine learning algorithms for seizure/non-seizure classification task. In this paper, mainly guidelines will be presented on how to use convolutional neural networks for the purpose of highly accurate classification of non-invasive EEG for patients with epilepsy. Convolutional neural networks can be pre-trained on a sample data as described in this paper and then implemented into an application or a device, which readjusts its parameters according to the patient-specific EEG patterns and thus can be further used as a seizure monitoring and alert system. The paper also demonstrated how transfer learning can be applied to create a patient-specific classifier with high accuracy.
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... Authors: Carelli, MD; Petrović, B.; Conway, LE; Oriani, L.; Kling, CL; Miller, V; Lombardi, CV; Ricotti, ME; Barroso, ACO; Collado, JM; Cinotti, L.; Storai, S.; Berra, F.; Todreas, NE; Ninokata, H.; Čavlina, N.; Grgić, D.; Oriolo, F.;... more
... Authors: Carelli, MD; Petrović, B.; Conway, LE; Oriani, L.; Kling, CL; Miller, V; Lombardi, CV; Ricotti, ME; Barroso, ACO; Collado, JM; Cinotti, L.; Storai, S.; Berra, F.; Todreas, NE; Ninokata, H.; Čavlina, N.; Grgić, D.; Oriolo, F.; Moraes ... Location and date: Peking, Kina, 16-20.05.2005 ...
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A probability-based approach is presented as the integration of probabilistic methods and deterministic modelling based on the finite element method. An existing finite element software package was linked to an existing probabilistic... more
A probability-based approach is presented as the integration of probabilistic methods and deterministic modelling based on the finite element method. An existing finite element software package was linked to an existing probabilistic package to analyse the complex mechanics that occur during the transient non-linear analysis of impact problems. This methodology is applied to a pipe whip analysis of a group-distribution-header, which results from a guillotine break, and subsequent impact with the adjacent building wall; this is a postulated accident for the Ignalina Nuclear Power Plant RBMK-1500 reactors. The uncertainties of material properties, component geometry data and loads were taken into consideration. The probabilities of failure of the impacted header and of the header support-wall were estimated given uncertainties in material properties, geometrical parameters and loading. The software ProFES was used for the probabilistic analysis and the finite element software NEPTUNE for deterministic structural integrity evaluation. The Monte Carlo Simulation, First Order Reliability method and Response Surface method were used in the probabilistic analysis.
Research Interests: Engineering, Monte Carlo Simulation, Monte Carlo, Finite element method, Finite Element, and 11 moreStructural Integrity, Reliability Analysis, Probabilistic Analysis, Probabilistic Method, Interdisciplinary Engineering, Non Linear Analysis, Material Properties, Nuclear Power Plant, Response Surface Method, Software Package, and Probability of Failure
Recently, theTheory of Stimulated Dynamics (TSD) has been developed for the analytical mod- elingandthesimulationofhybrid(continuous-discrete)systemsaswellasfordynamicreliabilityconsiderations.... more
Recently, theTheory of Stimulated Dynamics (TSD) has been developed for the analytical mod- elingandthesimulationofhybrid(continuous-discrete)systemsaswellasfordynamicreliabilityconsiderations. Inthelattercase,itwasalsocalledStimulus-DrivenTheoryofProbabilisticDynamics(SDTPD).Thetheorydeals with the concept of stimulus and how it can be implemented. A formerly used Markovian approach is provided in order to adaptTSD to practical applications, mostly in the context of Probabilistic SafetyAssessment (PSA). Since the application of TSD to the PSA concepts needs a formal approach, definitions and additional investi- gation related to uncertain scenario and sequence grouping are further considered.The considered sequence and scenario development should efficiently use the available computer resources and at the same time allow collect information for scenario analysis considering uncertainty, i.e. delineation of scenarios and representation of the uncertainty of certain scenarios.The con...
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info:eu-repo/semantics/publishe
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The International Reactor Innovative and Secure (IRIS) is an advanced, light-water cooled reactor expected to be deployment-ready in 2015 - 2017. IRISpsila power rating (1000 MWt or 335 MWe) is particular suitable for developing countries... more
The International Reactor Innovative and Secure (IRIS) is an advanced, light-water cooled reactor expected to be deployment-ready in 2015 - 2017. IRISpsila power rating (1000 MWt or 335 MWe) is particular suitable for developing countries and emerging markets with limited electric grid size and/or limited financial resources. IRIS has excellent capability to satisfy the Global Nuclear Energy Partnership (GNEP) requirements
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Straipsnyje nagrinėjama orlaivio kritimo tikimybe ant strategiškai svarbaus Lietuvoje objekto-Ignalinos atominės elektrinės (AE). Orlaivio kritimas ant Ignalinos AE sukeltų pakankamai didelį pavojų AE funkcionavimui, tuo pačiu ir... more
Straipsnyje nagrinėjama orlaivio kritimo tikimybe ant strategiškai svarbaus Lietuvoje objekto-Ignalinos atominės elektrinės (AE). Orlaivio kritimas ant Ignalinos AE sukeltų pakankamai didelį pavojų AE funkcionavimui, tuo pačiu ir reaktoriaus saugai. Skirtingų šalių techniniai eksperimentai ir skaičiavimai leidžia nustatyti, kad pagrindinių Ignalinos AE pastatų konstrukcijos išlaikytų lengvo lėktuvo kritimą, bet gali būti sugriautos, nukritus sunkiems ir kariniams lėktuvams. Todėl orlaivio (lėktuvo ar kito skraidančio aparato) kritimo dažnio ir pasėkmių Ignalinos AE teritorijoje įvertinimas yra svarbus, norint įvertinti riziką ir išvengti saugai svarbių sistemų pažeidimų. Straipsnyje tobulinamas lėktuvo kritimo tikimybės vertinimo modelis. Išvedama orlaivio kritimo tikimybės aplink Ignalinos AE spinduliu r skaičiavimo formule. Ji pritaikoma orlaivio kritimo tikimybės skaičiavimams su atnaujintais statistiniais duomenimis. Naudojant gautą priklausomybę buvo atlikta analizė, kaip orlai...
Various gas pipeline networks used for the transit of energy sources are some of the most important infrastructures. However, carrying gas from one point to another is not the only concern when planning the construction of a new network... more
Various gas pipeline networks used for the transit of energy sources are some of the most important infrastructures. However, carrying gas from one point to another is not the only concern when planning the construction of a new network or expanding an already existing one. The reliability and environmental impact of the system are crucial when evaluating the network and risks posed by potential gas leaks, fires, explosions, etc. Even though everyone admits that reliability is a key aspect of any system, its constraints will still be most likely neglected in the assessment of the pipeline project. How much energy is wasted by pushing an additional amount of gas through the pipeline network, which will eventually gush out of the pipeline because of one crack or another? Moreover, if this additional power or fuel consumption and related environmental impact are significant, how could it be reduced? In this paper, an approach is introduced for the simulation and quantification of how m...
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The Bayes' theorem is applied for reliability parameters estimation, control and testing alternatives investigation. The method how to control the reliability parameters considering data uncertainty and testing of safety important... more
The Bayes' theorem is applied for reliability parameters estimation, control and testing alternatives investigation. The method how to control the reliability parameters considering data uncertainty and testing of safety important system is also considered. The practical methodologies are described in order to show how to apply methods and models based on Bayesian approach, to calculate the updated failure rate and to specify and control test time or inspections required to keep an acceptable system failure rate or mean time before failure (MTBF) at a given uncertainty level, i.e. confidence level. Required test time estimation is based on MTBF objective or mean demand amount before failure during start for service and a desired confidence level. Similarly, the new testing interval can be proposed according to the design failure rate and reliability parameters control based on proposed inverted Bayesian approachLietuvos energetikos institutasVytauto Didžiojo universiteta
Lietuvos energetikos institutas, eugeniju@mail.lei.ltLietuvos energetikos institutas, robertas@mail.lei.ltLietuvos energetikos institutas, vaidas@mail.lei.ltMatematikos ir statistikos katedraVytauto Didžiojo universiteta
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UNSTRUCTURED Epileptic seizure detection and classification in clinical electroencephalogram data still is a challenge, and only low sensitivity with a high rate of false positives has been achieved with commercially available seizure... more
UNSTRUCTURED Epileptic seizure detection and classification in clinical electroencephalogram data still is a challenge, and only low sensitivity with a high rate of false positives has been achieved with commercially available seizure detection tools, which usually are patient non-specific. Epilepsy patients suffer from severe detrimental effects like physical injury or depression due to unpredictable seizures and no potential to bring themselves into the management of their own care. However, even in hospitals due to the high rate of false positives the seizure alert systems are of poor help for patients as tools of seizure detection are mostly trained on unrealistically clean data, containing little noise and obtained under controlled laboratory conditions, where patient groups are homogeneous, e.g. in terms of age or type of seizures. In this study, authors consider this important problem and techniques relevant in connected health and present the approach for detection and class...
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In this paper, we describe methods, models and software applied for dynamic system simulation using APL2.
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This report is based upon work from COST Action (ENJECT TD1405), supported by COST (European Cooperation in Science and Technology).
Research Interests: Information Technology, Health Sciences, ICT in Health, ICT for Development, Public Health, and 14 moreE Health, Medicine And Health Care, Telemedicine, Medicine, IT Governance, eHealth, ICT in Healthcare services, mHealth and eHealth, Medicine and Health Sciences, Technology In Medicine, University College Dublin, Ict for Health, Connected Health, and Public Policy
A distributed service oriented system which is developed to provide physical system or process monitoring, specification, analysis and simulation services are introduced in this paper. These services in separate components are developed... more
A distributed service oriented system which is developed to provide physical system or process monitoring, specification, analysis and simulation services are introduced in this paper. These services in separate components are developed to be used along with computer aided design systems to provide a support for designers in designing physical systems with efficient power consumption. All components of distributed system are presented to describe their role and interaction with Energy Simulator, which is developed by authors of this paper as a key component for simulation of the physical system and for calculation of energy consumption. Then, structure of Energy Simulator and its development process as well as solutions made to create flexible and scalable service oriented architecture is presented. Finally, the implementation of Energy Simulator and a case study devoted for designing of compressed air system is described together with discussion of various constraints of service oriented performance and practical simulation applying MATLAB based tools.
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Some safety systems of the Ignalina Nuclear Power Plant (NPP) operate in standby mode. An equipment of such systems is periodically tested and that allows timely detect and repair equipment failures. The periodic testing is an important... more
Some safety systems of the Ignalina Nuclear Power Plant (NPP) operate in standby mode. An equipment of such systems is periodically tested and that allows timely detect and repair equipment failures. The periodic testing is an important measure of ensuring systems' operability and reliability. However, during the test and repair the equipment cannot perform it's safety function, therefore too often testing decreases the availability of the system. This paper describes the mathematical model that represents how availability and reliability of the systems and their components depend on testing interval, taking into account different failure modes of the equipment. This model allows to find the optimal testing interval for the safety. As an example, the auxiliary feedwater pumps, that are a part of the Ignalina NPP Reactor Emergency Core Cooling System, are analysed. The model parameters calculation is based on Ignalina NPP data regarding pumps operation and failure as well a...
Introduction: Diabetic kidney disease (DKD) is one of the most enabling microvascular complications. Comparison of different treatment is problematic, as there are no clinical trials comparing different managements and patients’... more
Introduction: Diabetic kidney disease (DKD) is one of the most enabling microvascular complications. Comparison of different treatment is problematic, as there are no clinical trials comparing different managements and patients’ characteristics vary between the studies. Aim: to create probabilistic model, which allows predict DKD course according to the different treatment. Methods: A systematic literature review was performed, which allowed to estimate transition probabilities between the states of DKD - normoalbuminuria (NA), microalbuminuria (MA), diabetic nephropathy (NP), end stage renal disease. Due to the high complexity of dependence between transition rates and probabilities, Markov Chain Monte Carlo scheme was applied. Results: Of 1,812 articles identified after initial search, 95 publications had relevant data to estimate transition probabilities between DKD states. The lowest transition probabilities from MA to NP and the highest probability of remission from MA to NA wa...
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Kol buvo eksploatuojama Ignalinos AE, daugelis Lietuvos energetikos instituto (LEI) Branduolinių įrenginių saugos laboratorijos (BĮSL) mokslinių tyrimų buvo nukreipta branduolinių elektrinių saugos klausimams spręsti. Nuo 2006 m. LEI... more
Kol buvo eksploatuojama Ignalinos AE, daugelis Lietuvos energetikos instituto (LEI) Branduolinių įrenginių saugos laboratorijos (BĮSL) mokslinių tyrimų buvo nukreipta branduolinių elektrinių saugos klausimams spręsti. Nuo 2006 m. LEI įsitraukė į mokslinius tyrimus, susijusius su branduolių sintezės tematika. Branduolių sintezė – tai procesas, kurio metu susijungia du lengvi branduoliai, pavyzdžiui, vandenilio izotopai deuteris ir tritis, sudarydami naują helio branduolį, o šio proceso metu išsiskiria milžiniškas energijos kiekis. Toks procesas vyksta ir žvaigždėse, o pasaulio mokslininkai sprendžia, kaip jį būtų galima suvaldyti ir pritaikyti Žemėje. Jei 2006 m. LEI vykdė tik nedidelį projektą, susijusį su vienu iš ITER reaktoriaus saugos aspektų, tai vėliau LEI BĮSL mokslininkai plėtė savo veiklos apimtis ir įsitraukė į naujas tyrimų sritis: neutronų pernašos procesų tyrimai, įrangos patikimumo tyrimai, įvairių konstrukcijų struktūrinio vientisumo tyrimai, t. t. Jau 2013 m. kartu s...
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Natural gas is commonly used as a fuel. Large distances between natural gas supply sources and consumers has led to extensive networks of natural gas pipelines. Since natural gas is a flammable and explosive fuel, it is hazardous and its... more
Natural gas is commonly used as a fuel. Large distances between natural gas supply sources and consumers has led to extensive networks of natural gas pipelines. Since natural gas is a flammable and explosive fuel, it is hazardous and its transportation has inherent risks associated with potential damage. Accidental gas pipeline explosions could lead to extreme destruction and negative consequences. In order to estimate and reduce probability and potential damage of such explosions the good understanding of involved phenomena and ability to simulate them are needed. This paper presents hazard analysis and consequences assessment of gas pipeline rupture and natural gas explosion. Various mathematical models are described in the methodological part of the work. They help to figure out the hazard of the gas pipeline rupture and assess the size of risky zone reflecting the place of potential disaster. Also the probability of the gas explosion in relation to the particular gas pipeline is...
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The Theory of Stimulated Dynamics (TSD) has been introduced for the analytical modelling and the simulation of hybrid (continuous-discrete) system as well as for dynamic re- liability consideration. The theory deals with the concept of... more
The Theory of Stimulated Dynamics (TSD) has been introduced for the analytical modelling and the simulation of hybrid (continuous-discrete) system as well as for dynamic re- liability consideration. The theory deals with the concept of stimulus and delay and how they can be implemented. Different issues and extension of Markovian approach is discussed in or- der to simulate dynamic system for practical applications. For this the uncertainty analysis ap- proach was developed and integrated with TSD. The modelling of stimulated dynamics as well as uncertainty and sensitivity assessment allows the detail simulation and representation of sys- tem characteristics uncertainty. The developed approach for system analysis can be efficiently used to estimate system reliability and at same time analyze the uncertainty of this estimate.