Sound radiation and sound insulation performances of maritime bulkheads

The research of materials matching low weight and high resistance has always been a key factor in the shipbuilding industry to increase performances and loading capacity. Nowadays, other issues add up to economical convenience, and building quiet ships is important not only for passengers and cabin crew, but also to make harbor areas more comfortable and to respect the aquatic environment. In this context, using sandwich or composite materials must be carefully evaluated and the sound insulation performances must be considered throughout all stages of the design process. This work presents some evaluations about the sound insulation performances of a ribbed fiberglass bulkhead and of a balsa-core sandwich bulkhead. In particular, the bending stiffness and the sound transmission loss obtained by sound transmission suites and mobility measurements are provided. From such measurements it has also been possible to determine the radiation efficiency of the structures, whose optimization is particularly important when a reduction of the noise pollution is required

Simulation product fidelity: a qualitative & quantitative system engineering approach

La modélisation informatique et la simulation sont des activités de plus en plus répandues lors de la conception de systèmes complexes et critiques tels que ceux embarqués dans les avions. Une proposition pour la conception et réalisation d'abstractions compatibles avec les objectifs de simulation est présentée basés sur la théorie de l'informatique, le contrôle et le système des concepts d'ingénierie. Il adresse deux problèmes fondamentaux de fidélité dans la simulation, c'est-à-dire, pour une spécification du système et quelques propriétés d'intérêt, comment extraire des abstractions pour définir une architecture de produit de simulation et jusqu'où quel point le comportement du modèle de simulation représente la spécification du système. Une notion générale de cette fidélité de la simulation, tant architecturale et comportementale, est expliquée dans les notions du cadre expérimental et discuté dans le contexte des abstractions de modélisation et des relations d'inclusion. Une approche semi-formelle basée sur l'ontologie pour construire et définir l'architecture de produit de simulation est proposée et démontrée sur une étude d'échelle industrielle. Une approche formelle basée sur le jeu théorique et méthode formelle est proposée pour différentes classes de modèles des systèmes et des simulations avec un développement d'outils de prototype et cas des études. Les problèmes dans la recherche et implémentation de ce cadre de fidélité sont discutées particulièrement dans un contexte industriel.In using Modeling and Simulation for the system Verification & Validation activities, often the difficulty is finding and implementing consistent abstractions to model the system being simulated with respect to the simulation requirements. A proposition for the unified design and implementation of modeling abstractions consistent with the simulation objectives based on the computer science, control and system engineering concepts is presented. It addresses two fundamental problems of fidelity in simulation, namely, for a given system specification and some properties of interest, how to extract modeling abstractions to define a simulation product architecture and how far does the behaviour of the simulation model represents the system specification. A general notion of this simulation fidelity, both architectural and behavioural, in system verification and validation is explained in the established notions of the experimental frame and discussed in the context of modeling abstractions and inclusion relations. A semi-formal ontology based domain model approach to build and define the simulation product architecture is proposed with a real industrial scale study. A formal approach based on game theoretic quantitative system refinement notions is proposed for different class of system and simulation models with a prototype tool development and case studies. Challenges in research and implementation of this formal and semi-formal fidelity framework especially in an industrial context are discussed

Modeling and Analyzing Cyber-Physical Systems Using Hybrid Predicate Transition Nets

Cyber-Physical Systems (CPSs) are software controlled physical devices that are being used everywhere from utility features in household devices to safety-critical features in cars, trains, aircraft, robots, smart healthcare devices. CPSs have complex hybrid behaviors combining discrete states and continuous states capturing physical laws. Developing reliable CPSs are extremely difficult. Formal modeling methods are especially useful for abstracting and understanding complex systems and detecting and preventing early system design problems. To ensure the dependability of formal models, various analysis techniques, including simulation and reachability analysis, have been proposed in recent decades. This thesis aims to provide a unified formal modeling and analysis methodology for studying CPSs. Firstly, this thesis contributes to the modeling and analysis of discrete, continuous, and hybrid systems. This work enhances modeling of discrete systems using predicate transition nets (PrTNs) by fully realizing the underlying specification through incorporating the first-order logic with set theory, improving the type system, and providing incremental model composition. This work enhances the technique of analyzing discrete systems using PrTN by improving the simulation algorithm and its efficient implementation. This work also improves the analysis of discrete systems using SPIN by providing a more accurate and complete translation method. Secondly, this work contributes to the modeling and analysis of hybrid systems by proposing an extension of PrTNs, hybrid predicate transition nets (HPrTNs). The proposed method incorporates a novel concept of token evolution, which nicely addresses the continuous state evolution and the conflicts present in other related works. This work presents a powerful simulation capability that can handle linear, non-linear dynamics, transcendental functions through differential equations. This work also provides a complementary technique for reachability analysis through the translation of HPrTN models for analysis using SpaceEx

Energy-efficient resource management for continuous scenario fulfillment by UAV fleets

Unbemannte Luftfahrzeuge (unmanned aerial vehicles, UAV) sind autonom fliegende und flexibel einsetzbare mobile Roboter, welche durch ihre große Flexibilität und Erweiterbarkeit viele Möglichkeiten bieten. Insbesondere im Bereich der Katastrophenbewältigung erlangen sie immer stärkere Bedeutung, da die Aufgaben zur Aufklärung im Gebiet und zur Erschaffung einer Kommunikationsinfrastruktur ungebunden und schnell durch sie bewältigt werden können. Der Forschungsschwerpunkt dieser Arbeit liegt in der Herausforderung der Ressourcenverwaltung in einem solchen Szenario. Während die Priorität des UAV Einsatzes klar darin besteht die Katastrophenbekämpfung unterbrechungsfrei zu unterstützten, muss ebenso auf die Verwaltung limitierter Ressourcen, wie elektrischer Energie, eingegangen werden. Wir präsentieren ein entsprechendes Systemdesign einer Ressourcenverwaltung und Strategien zur Verbesserung der Leistung und damit zur Erhöhung der Energieeffizienz des Gesamtsystems. Die Implementierung und gründliche Untersuchung eines solchen komplexen Systems von Teilsystemen ist verbunden mit hohen finanziellen Kosten, großem Test-Risiko und einer langen Entwicklungsdauer. Aus diesem Grund setzt diese Arbeit auf abstrakte ausführbare Modelle der Umgebung, des Verwaltungssystems und der UAVs. Die Verwendung dieser Modelle in einer Massensimulation mit beliebiger Komplexität und Konfiguration ermöglicht die schnelle und kostengünstige Verifikation der Funktionstüchtigkeit und die Bewertung verschiedener Verwaltungsstrategien. Im Vergleich zu der präsentierten trivialen Lösung ist die entwickelte verbesserte Lösung in der Lage den zeitlichen Anteil einzelner UAVs im Missionseinsatz zu erhöhen und die insgesamt nötige Menge an UAVs für die dauerhafte Abdeckung aller Aufgaben zu reduzieren. Die Schritte zur Optimierung reduzierten im analysierten Beispiel den Gesamtenergiebedarf aller UAVs um nahezu 20 Prozent.Unmanned aerial vehicles (UAV) are autonomous and flexible robotic systems with a remarkable degree of freedom and extendibility. They are especially valuable in the context of disaster scenarios, where arising use cases for reconnaissance and mobile communication infrastructure creation have to be addressed rapidly and unbound from restrictions in the operation field. The research focus of this thesis lies in the challenge of resource management during such an application. While the priority of the UAV utilization lies on uninterrupted task execution, concern for limited resources, like electrical energy, and resultant maintenance processes has to be dealt with on a lower management layer. We present a resource management system design and multiple competing strategies to improve its performance and overall energy efficiency. The implementation and thorough evaluation of such a complex system of systems is linked to high costs, great operational risks, and a long development time. For that reason, we developed executable models representing the environment, the resource management system, and the UAV. Through mass simulation of these models in various scenario constellations and configurations, we are able to verify the applicability of our proposed resource management system and to evaluate and optimize various aspects of its processes. In comparison to a presented trivial solution, we are able to increase the UAV flight utilization efficiency and decrease the needed amount of provided UAVs in the scenario. Our optimization efforts reduce the overall energy demand of UAVs in the analyzed example scenario by almost 20 percent

Smart simulation and modelling for complex cancer systems

Clinical pathways are an effective and effcient approach in standardising the progression of treatment, to support patient care and facilitate clinical decision making. This research project was funded by KESS2 in collaboration with a company partner - Velindre Cancer Centre (VCC). This thesis develops effcient and sustainable methods for pathway mapping, modelling and improving, within the context of developing a state-of-the-art decision support tool. A particular focus on lung cancer is considered for method construction and investigations. The clinical pathways are mapped through representing each pathway as a string of letters. This enabled the development of the modifed Needleman-Wunsch metric, to allow for consideration of both data and medical expert information, for the use with k-medoids clustering. The key contribution of automating the simulation build and necessary input parameters, is developed. Models can be constructed for four routing procedures, namely Raw Pathways, Full Transitions, Cluster Transitions and Process Medoids, that explore progressively less complex and varied interpretations of the clinical pathways. Improvements can then be investigated for aligning capacity and demand. Combining this amounted to the development of Sim.Pro.Flow, an open access decision support tool, that contains all methods discussed in this thesis. The generalised approach allows for these methods, and Sim.Pro.Flow, to be suitably exible for application with process data from both healthcare and other industries

Framework development for improving arrival processing of pilgrims at Hajj and Umrah airport terminals

Millions of Muslims around the world perform the Hajj, a mandatory religious journey to the holy city of Mecca, at least once in their lifetime. Therefore, hundreds of thousands of pilgrims arrive weekly at Jeddah and Medina Airports during the Hajj period determined by the Islamic calendar. Numerous research studies have been published on the health, security, risk management and logistics aspects of the mass gathering. However, studies on pilgrims’ wait times, flow and satisfaction at the Hajj and Umrah Terminals (HT)s are very limited. The research evaluating the inbound passenger domain is especially limited. Therefore, this study contributes to the literature by combining different perspectives regarding the inefficiency of HT processes. Furthermore, this study proposes and investigates various aspects to improve the processing of arriving passengers at HTs. It does so by identifying and studying the factors that impede the flow of passengers within these terminals from users’ and providers’ perspectives. This research aims to contribute by developing an innovative integrated framework to improve the flow of pilgrims through arrival terminals and determining how large crowds at airports can be better managed. To meet the study’s aims, a simulation model is developed to verify and confirm the performance of arrival passenger processes at HTs by conducting a mixedmethods analysis and integrating the numerical results of the agent-based and discrete-event simulation models. This study creates a problematic review matrix based on users’ and providers’ perspectives. In addition, the survey on providers’ perspectives indicates that there are five factors, human, infrastructure, operational, technical and organisational factors, influencing arrival passenger processes at HTs and interacting with level of service (LoS) variables. The study indicates the suboptimal processes at airport terminals to focus on the factors negatively affecting the HT processes. In addition, the research highlights the role of terminal configurations. This study compares two airports in terms of peak demand patterns. According to the study, sharp peaks can have strong negative impacts on HTs, while evenly distributed demand can improve LoS at HTs. The simulation model outcomes verify and confirm the parameters and factors influencing LoS. In addition, the study’s integrated framework provides diverse viewpoints on the operational processes at HTs, while the density map matrix helps to classify the processes. This study applies what-if scenarios to identify the impact of pilgrims’ experience and biometric characteristics and finds that inexperience and certain biometric characteristics have negative impacts on LoS. Limitations of the study and suggestions for future research are discussed.Transport System

Dynamics of Technology Acceptance to the Sustainability of eHealth Systems in Resource Constrained Environments

Healthcare in developing countries is confronted with a shortage of skilled healthcare workforce, medical errors, inequity and inefficient healthcare service delivery. Innovative ways of solving healthcare problems through Information and communication technology (ICT) can improve the efficiency, effectiveness, access and quality of the healthcare system. Despite highly anticipated benefits of eHealth system to improve the efficiency of healthcare delivery, the healthcare had barely begun to take advantage of ICT mainly in a resource-constrained environment. The implementation of eHealth systems in developing countries could not proceed beyond the pilot phase to demonstrate sustainability in a large-scale rollout. The general research problem in this thesis focuses on how factors of eHealth implementation interplay to influence technology and information use to ensure the long-term sustainability of eHealth in resource-constrained settings. Systems thinking and system dynamics modelling method were used to handle complexity in the implementation of eHealth. Moreover, sustainability theory, technology acceptance model (TAM) and IS success models were used to develop a system dynamics model of sustainable eHealth implementation. The socio-technical, techno-organizational and techno-economic factors of sustainable eHealth systems are discussed to address the research objectives. The system dynamics simulation model of sustainable eHealth implementation is developed, verified, validated and tested. This applied research study focused on addressing the problems of sustainable eHealth systems implementation in resource-constrained environments. The model-based theory-building research study followed in this thesis aimed at enhancing the understanding of sustainable eHealth implementation in a resource-constrained environment to maximize the acceptance of eHealth by the end-users. Both the ontological and epistemological assumptions of this research study supported the position of the constructivist research paradigm. Methodologically, this study mainly applies qualitative research methodology which is common in the interpretive approach. Structured and semi-structured questionnaires were used to elicit information from purposefully sampled eHMIS and SmartCare health facilities in Ethiopia. Field notes, document review, interview and focus group discussion data were analysed using ATLAS.ti software. Vensim DSS Version 6.3D was used to model and simulate the system dynamics model. Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) approach was followed in the systematic literature review of techno-economic factors. The simulation results confirmed that the ‘effectiveness of training’ was a dominant factor to improve the ‘acceptance rate’ of eHMIS and SmartCare in the socio-technical dimension of sustainable eHealth implementation. The adequacy of ICT and healthcare workforce within eHealth implementing facility and end-users’ familiarity with digital technology showed a stronger influence on the ‘acceptance rate’ of both eHMIS and SmartCare systems in the techno-organizational dimension. An economic incentive, funding duration, funding amount, funding source and economic benefit are identified as techno-economic factors that influence the long-term sustainability of eHealth projects.Thesis (PhD)--University of Pretoria, 2019.Graduate School of Technology Management (GSTM)PhDUnrestricte

RIODD 2016 « Energie, environnement et mutations sociales »

International audienceLe RIODD a tenu son 11ème congrès annuel du mercredi 6 au vendredi 8 juillet 2016 à St-Etienne. Il s'est déroulé à l'Ecole des Mines de Saint-Étienne. L’organisation de ce 11ème congrès annuel du RIODD était portée par l’Institut Henri Fayol de l’Ecole des Mines de St-Etienne. Cette manifestation scientifique à caractère pluridisciplinaire et de dimension internationale s’est inscrite dans le cadre du Bicentenaire de l’Ecole des Mines de St-Etienne en 2016