Fuzzy-Analysis in a Generic Polymorphic Uncertainty Quantification Framework

In this thesis, a framework for generic uncertainty analysis is developed. The two basic uncertainty characteristics aleatoric and epistemic uncertainty are differentiated. Polymorphic uncertainty as the combination of these two characteristics is discussed. The main focus is on epistemic uncertainty, with fuzziness as an uncertainty model. Properties and classes of fuzzy quantities are discussed. Some information reduction measures to reduce a fuzzy quantity to a characteristic value, are briefly debated. Analysis approaches for aleatoric, epistemic and polymorphic uncertainty are discussed. For fuzzy analysis α-level-based and α-level-free methods are described. As a hybridization of both methods, non-flat α-level-optimization is proposed. For numerical uncertainty analysis, the framework PUQpy, which stands for “Polymorphic Uncertainty Quantification in Python” is introduced. The conception, structure, data structure, modules and design principles of PUQpy are documented. Sequential Weighted Sampling (SWS) is presented as an optimization algorithm for general purpose optimization, as well as for fuzzy analysis. Slice Sampling as a component of SWS is shown. Routines to update Pareto-fronts, which are required for optimization are benchmarked. Finally, PUQpy is used to analyze example problems as a proof of concept. In those problems analytical functions with uncertain parameters, characterized by fuzzy and polymorphic uncertainty, are examined

Safety Analysis Methods for Complex Systems in Aviation

Each new concept of operation and equipment generation in aviation becomes more automated, integrated and interconnected. In the case of Unmanned Aircraft Systems (UAS), this evolution allows drastically decreasing aircraft weight and operational cost, but these benefits are also realized in highly automated manned aircraft and ground Air Traffic Control (ATC) systems. The downside of these advances is overwhelmingly more complex software and hardware, making it harder to identify potential failure paths. Although there are mandatory certification processes based on broadly accepted standards, such as ARP4754 and its family, ESARR 4 and others, these standards do not allow proof or disproof of safety of disruptive technology changes, such as GBAS Precision Approaches, Autonomous UAS, aircraft self-separation and others. In order to leverage the introduction of such concepts, it is necessary to develop solid knowledge on the foundations of safety in complex systems and use this knowledge to elaborate sound demonstrations of either safety or unsafety of new system designs. These demonstrations at early design stages will help reducing costs both on development of new technology as well as reducing the risk of such technology causing accidents when in use. This paper presents some safety analysis methods which are not in the industry standards but which we identify as having benefits for analyzing safety of advanced technological concepts in aviation

Dependability analysis of a safety critical system: the LHC Beam Dumping System at CERN

Il sistema di estrazione del fascio del nuovo acceleratore LHC del CERN (LHC Beam Dumping System, LBDS) ha il compito di rimuovere il fascio di particelle dall’anello in caso di anomalie, guasti nella macchina o al termine di una operazione. Il sistema rappresenta uno dei componenti critici per la sicurezza dell’acceleratore LHC. Il suo malfunzionamento puo’ portare alla mancata o parziale estrazione del fascio che, per le elevatissime energie raggiunte (7 TeV), ha la capacita’ di distruggere i magneti superconduttori dell’acceleratore e determinare l’arresto delle operazioni per un lungo periodo. La tesi affronta lo studio della sicurezza del sistema di estrazione del fascio di particelle ed il suo impatto sulla vita operativa del sistema in termini di numero aborto missioni(failsafe modes). Un modello dinamico ad eventi discreti stocastico del processo di guasto del sistema e’ stato ricavato partendo da una accurata analisi della sua architettura, dei modi e delle statistiche di guasto di ciascun componente. Il modello e’ stato analizzato rispetto a diversi scenari operativi, fornendo le stime della sicurezza e del numero aborto missioni per un anno di operazioni. L’analisi ha anche valutato l’efficacia delle soluzioni architetturali che sono state adottate per tollerare e prevenire il guasto nei componenti piu’ critici. I risultati ottenuti hanno dimostrato che il sistema rispetta i requisiti SIL3 dello standard di sicurezza IEC 61508, e non interferisce oltre misura sul normale funzionamento della macchina. Lo studio include anche una valutazione della sicurezza complessiva ottenuta per mezzo del sistema di protezione di cui il sistema LBDS e’ parte integrante

Operations Management

Global competition has caused fundamental changes in the competitive environment of the manufacturing and service industries. Firms should develop strategic objectives that, upon achievement, result in a competitive advantage in the market place. The forces of globalization on one hand and rapidly growing marketing opportunities overseas, especially in emerging economies on the other, have led to the expansion of operations on a global scale. The book aims to cover the main topics characterizing operations management including both strategic issues and practical applications. A global environmental business including both manufacturing and services is analyzed. The book contains original research and application chapters from different perspectives. It is enriched through the analyses of case studies

A model-based approach to System of Systems risk management

The failure of many System of Systems (SoS) enterprises can be attributed to the inappropriate application of traditional Systems Engineering (SE) processes within the SoS domain, because of the mistaken belief that a SoS can be regarded as a single large, or complex, system. SoS Engineering (SoSE) is a sub-discipline of SE; Risk Management and Modelling and Simulation (M&S) are key areas within SoSE, both of which also lie within the traditional SE domain. Risk Management of SoS requires a different approach to that currently taken for individual systems; if risk is managed for each component system then it cannot be assumed that the aggregated affect will be to mitigate risk at the SoS level. A literature review was undertaken examining three themes: (1) SoS Engineering (SoSE), (2) M&S and (3) Risk. Theme 1 of the literature provided insight into the activities comprising SoSE and its difference from traditional SE with risk management identified as a key activity. The second theme discussed the application of M&S to SoS, providing an output, which supported the identification of appropriate techniques and concluding that, the inherent complexity of a SoS required the use of M&S in order to support SoSE activities. Current risk management approaches were reviewed in theme 3 as well as the management of SoS risk. Although some specific examples of the management of SoS risk were found, no mature, general approach was identified, indicating a gap in current knowledge. However, it was noted most of these examples were underpinned by M&S approaches. It was therefore concluded a general approach SoS risk management utilising M&S methods would be of benefit. In order to fill the gap identified in current knowledge, this research proposed a new model based approach to Risk Management where risk identification was supported by a framework, which combined SoS system of interest dimensions with holistic risk types, where the resulting risks and contributing factors are captured in a causal network. Analysis of the causal network using a model technique selection tool, developed as part of this research, allowed the causal network to be simplified through the replacement of groups of elements within the network by appropriate supporting models. The Bayesian Belief Network (BBN) was identified as a suitable method to represent SoS risk. Supporting models run in Monte Carlo Simulations allowed data to be generated from which the risk BBNs could learn, thereby providing a more quantitative approach to SoS risk management. A method was developed which provided context to the BBN risk output through comparison with worst and best-case risk probabilities. The model based approach to Risk Management was applied to two very different case studies: Close Air Support mission planning and the Wheat Supply Chain, UK National Food Security risks, demonstrating its effectiveness and adaptability. The research established that the SoS SoI is essential for effective SoS risk identification and analysis of risk transfer, effective SoS modelling requires a range of techniques where suitability is determined by the problem context, the responsibility for SoS Risk Management is related to the overall SoS classification and the model based approach to SoS risk management was effective for both application case studies

Sustainable Construction Engineering and Management

This Book is a Printed Edition of the Special Issue which covers sustainability as an emerging requirement in the fields of construction management, project management and engineering. We invited authors to submit their theoretical or experimental research articles that address the challenges and opportunities for sustainable construction in all its facets, including technical topics and specific operational or procedural solutions, as well as strategic approaches aimed at the project, company or industry level. Central to developments are smart technologies and sophisticated decision-making mechanisms that augment sustainable outcomes. The Special Issue was received with great interest by the research community and attracted a high number of submissions. The selection process sought to balance the inclusion of a broad representative spread of topics against research quality, with editors and reviewers settling on thirty-three articles for publication. The Editors invite all participating researchers and those interested in sustainable construction engineering and management to read the summary of the Special Issue and of course to access the full-text articles provided in the Book for deeper analyses

Process management in food supply chains : a case study

Purpose: The aim of this article is to identify processes in the horses feed supply chains implemented for the needs of sporting stables, together with an indication of the factors determining their efficient management and to propose methods to improve the process. Design/Approach: The research was conducted using qualitative methods. As part of the research procedure, process analysis was carried out using the method of mapping processes in the horse feed supply chain. To analyse and evaluate the examined processes were presented in the form of graphical maps developed using the iGrafx software. Findings: The results of the study indicate that the coordination and integration of logistics processes has a significant impact on the efficiency of the feed supply chain. It is necessary to focus process management on building partnerships in the supply chain to ensure high quality horse nutrition. Practical Implications: The results can be used to improve the supply chain, which is important for owners, breeders, trainers, and animal caregivers - as well as sports, insurance, or veterinary institutions. Nutritional issues are subject to detailed analysis in the event of success and at the time of occurrence of health problems ending with surgical intervention or death of the horse. Originality/Value: Due to the growing importance of these issues for the efficient operation of the feed chain for horses, it is necessary to understand and promote the aspect of coherent, integrated process management in the scientific and practical dimension. An important element of breeding and training activities is the proper recognition of individual elements and relationships in feed supply chains, as well as the factors determining them.peer-reviewe