Applying RAMSSHEEP analysis for risk-driven maintenance

The Ministry of Infrastructure and the Environment of The Netherlands and Rijkswaterstaat (RWS) aim to launch a risk-driven maintenance concept named RAMSSHEEP. Engineering and consultancy companies are expected to develop the RAMSSHEEP concept in order to create better maintenance strategies. The objective is to investigate whether RAMSSHEEP can be applied as a risk-driven maintenance tool for primary flood defence systems in The Netherlands. By applying a probabilistic approach to a flooding problem, more insight is gained in the advantages and disadvantages of RAMSSHEEP. This paper addresses the problem which primary flood defence systems experience with respect to maintenance strategies. Often external political pressure is applied to improve reliability and availability and to reduce costs significantly. Therefore this paper suggests an approach that is able to find an optimal maintenance strategy by finding the economic most beneficial maintenance interval.Values and TechnologyTechnology, Policy and Managemen

Zwavelzuur uit zwavelwaterstof

Document(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

A decision support method for design and operationalization of search and rescue in maritime emergency

Design and operationalization for Search and Rescue (SAR) activities are unstructured and complex multi-criteria decision-making problems, especially for maritime emergency scenario. There is a lack of decision support methods based on intelligent algorithms to shorten the response time and to reduce the loss of life and property. The primary purpose of this paper is to develop a three-stage decision support method to optimize the type and number of resources when making SAR schemes so as to formulate emergency response more efficiently and effectively. First, the main influential factors are identified in Stage 1, including the particulars of environmental indices, search objects and SAR resources. Next, in Stage 2, important variables are defined for generating probability distribution maps, identifying the search areas, and evaluating the objective function in Stage 3. Two intelligent algorithms, the Differential Evolution (DE) and Non-Dominated Sorting Genetic Algorithm-II (NSGA-II), are used to find appropriate SAR schemes and help resources scheduling. Finally, the feasibility and validity of the model are verified by a ship collision example. From the simulation of the SAR task assignment and decision preference analysis, the proposed method can be used for further improvement of SAR design and operationalization.Safety and Security Scienc

Individual preferences in security risk decision making: an exploratory study under security professionals

Risk assessments in the (cyber) security domain are often, if not always, based on subjective expert judgement. For the first time, to the best of our knowledge, the individual preferences of professionals from the security domain are studied. In on online survey they are asked to mention, rate and rank their preferences when assessing a security risk. The survey setup allows to differentiate between easily accessible or “on top of mind” attributes and guided or stimulated attributes. The security professionals are also challenged to both non-compensatory and compensatory decision making on the relevance of the attributes. The results of this explorative study indicate a clear difference and shift in the individual perceived relevance of attributes in these different settings. Another remarkable finding of this study is the predominant focus on impact attributes by the respondents and the less significant position of likelihood or probability. The majority of professionals seem to ignore likelihood in their security risk assessment. This might be due to so called probability neglect as introduced by other scholars. the security in organisations and society is depending on the assessment and judgement of these professionals, understanding their preferences and the influence of cognitive biases is paramount. This study contributes to this body of knowledge and might raise attention to this important topic in both the academic and professional security domain.Safety and Security Scienc

Impact of occupational risk prevention measures during process disturbances in TBM tunnelling

When process disturbances occur, workers on the Tunnel Boring Machine (TBM) will need to operate outside safe zones, reducing or eliminating the safety barrier ‘distance’ between them and potential sources of risk. Consequently, disturbances have a higher risk potential than regular TBM operations. By comparing the risks of registered process disturbances with regular TBM process, we try to predict accident scenarios. The exposure risk is defined by the exposure time and the injury severity. Exposure times have been determined from case histories, where on average 11% of the construction period is attributed to disturbances. The potential number of casualties, including less common incident scenarios, have been determined using an accident scenario building toolkit. We find that factors that contribute most to occupational risk reduction are the (correct) use of available risk prevention measures, correct design of safety barriers and making these barriers available to personnel, as well as detailed planning of procedures such that specific tasks are performed in a uniform and predetermined manner.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Safety and Security ScienceGeo-engineerin

Detecting changes in extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

International audienceExtreme hydro-meteorological events have become the focus of more and more studies in the last decade. Due to the complexity of the spatial pattern of changes in precipitation processes, it is still hard to establish a clear view of how precipitation has changed and how it will change in the future. In the present study, changes in extreme precipitation and streamflow processes in the Dongjiang River Basin in southern China are investigated with several nonparametric methods, including one method (Mann-Kendall test) for detecting trend, and three methods (Kolmogorov?Smirnov test, Levene's test and quantile test) for detecting changes in probability distribution. It was shown that little change is observed in annual extreme precipitation in terms of various indices, but some significant changes are found in the precipitation processes on a monthly basis, which indicates that when detecting climate changes, besides annual indices, seasonal variations in extreme events should be considered as well. Despite of little change in annual extreme precipitation series, significant changes are detected in several annual extreme flood flow and low-flow series, mainly at the stations along the main channel of Dongjiang River, which are affected significantly by the operation of several major reservoirs. To assess the reliability of the results, the power of three non-parametric methods are assessed by Monte Carlo simulation. The simulation results show that, while all three methods work well for detecting changes in two groups of data with large sample size (e.g., over 200 points in each group) and large differences in distribution parameters (e.g., over 100% increase of scale parameter in Gamma distribution), none of them are powerful enough for small data sets (e.g., less than 100 points) and small distribution parameter difference (e.g., 50% increase of scale parameter in Gamma distribution). The result of the present study raises the concern of the robustness of statistical change-detection methods, shows the necessity of combined use of different methods including both exploratory and quantitative statistical methods, and emphasizes the need of physically sound explanation when applying statistical test methods for detecting changes

Bayesian network model to distinguish between intentional attacks and accidental technical failures: a case study of floodgates

Water management infrastructures such as floodgates are critical and increasingly operated by Industrial Control Systems (ICS). These systems are becoming more connected to the internet, either directly or through the corporate networks. This makes them vulnerable to cyber-attacks. Abnormal behaviour in floodgates operated by ICS could be caused by both (intentional) attacks and (accidental) technical failures. When operators notice abnormal behaviour, they should be able to distinguish between those two causes to take appropriate measures, because for example replacing a sensor in case of intentional incorrect sensor measurements would be ineffective and would not block corresponding the attack vector. In the previous work, we developed the attack-failure distinguisher framework for constructing Bayesian Network (BN) models to enable operators to distinguish between those two causes, including the knowledge elicitation method to construct the directed acyclic graph and conditional probability tables of BN models. As a full case study of the attack-failure distinguisher framework, this paper presents a BN model constructed to distinguish between attacks and technical failures for the problem of incorrect sensor measurements in floodgates, addressing the problem of floodgate operators. We utilised experts who associate themselves with the safety and/or security community to construct the BN model and validate the qualitative part of constructed BN model. The constructed BN model is usable in water management infrastructures to distinguish between intentional attacks and accidental technical failures in case of incorrect sensor measurements. This could help to decide on appropriate response strategies and avoid further complications in case of incorrect sensor measurements.Safety and Security ScienceOrganisation and Governanc

A decision-support model for time-dependent investments in flood defences

This poster presents the framework of a decision support model for time-dependent investments in structural flood risk mitigation measures.Hydraulic EngineeringCivil Engineering and Geoscience

Managing knowledge for future-proof tunnels in The Netherlands

The COB is The Netherlands Knowledge Centre for Underground Construction and Underground Space. Over sixty organisations, from government, industry and knowledge institutes, work together to learn and develop smart solutions regarding tunnels. This network has developed a long-term vision on tunnels in The Netherlands. As a result, nineteen tunnels and all stakeholders collaborate on eight research topics of our tunnel programme. We found common ground and the key issues are already being addressed in both practice and science. Topics include risks, construction failure, modular renovation, digital tunnel twin, virtual testing, virtual education and system safety. The way clients, science and industry work together within the COB network has been a major precondition to achieve these great results in such a short period of time.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin

Hoe bruikbaar is de Zandmotor?: Eerste tussentijdse verkenning naar de haalbaarheid en bruikbaarheid van de pilot Zandmotor 2011-2013

In 2010 en 2011 is voor de kust van Zuid-Holland ter hoogte van Ter Heijde een experimentele megasuppletie aangelegd, 'de Zandmotor'. Sinds de aanleg vindt uitgebreide monitoring plaats naar het functioneren van deze innovatie. In 2016 en 2021 zullen respectievelijk een eerste en een eindevaluatie plaatsvinden. De beleidsvraag die in 2021 zal moeten worden beantwoord: is de Zandmotor bruikbaar en eventueel in te zetten op andere locaties in Nederland? De natuurlijke processen die plaatsvinden op de Zandmotor nemen meerdere jaren in beslag. Daarom kan pas in 2016 kan een eerste antwoord worden gegeven op de vraag of de pilot Zandmotor bruikbaar is. De eerste indicaties op basis van de opgezette monitoring volgens het MEP, de eerste tussentijdse Beleidsevaluatie en een aantal gehouden interviews met betrokken experts zijn positief. In deze eerste tussentijdse Rapportage Bruikbaarheid Zandmotor 2013, staan de volgende vragen centraal: - Voldoet de Zandmotor aan de gestelde doelen? - Is de Zandmotor beheerbaar? - Wat is er nodig voor besluitvorming en communicatie? - Is de Zandmotor financierbaar? - Is de Zandmotor realiseerbaar en welke locatie zou geschikt zijn voor een pilot Zandmotor?Zandmoto