1,720,965 research outputs found
Behaviour models for the evacuation of a motorway tunnel
No full textThis work focuses on the human behaviour during an evacuation of a motorway tunnel. First of all all the type of signalization have been taken into account, according with the current legislation updated after the Mont Blanc Tunnel tragedy of March 1999. In order to study how people behaves in case of emergency an interesting methodology has been applied: Thomas Saaty's Analytic Hierarchic Process (AHP), based on matrix weight calculation. This methodology has been implemented in a simulation model that considers different scenarios, based on the signs' position. All the scenarios then have been analysed and evaluated using well-known techniques such as Analysis of Variance (ANOVA) and Response Surface Methodology (RSM)
Literature review about supply chain vulnerability and resiliency
No full textThis paper focuses on the literature review regarding the vulnerability of supply chains and the relative resiliency. After identifying the most common threats (that can have high or low probability of occurrence) that affect the supply chain integrity, some best practices from real cases are provided in order to provide the key factors to build a resilient supply chain. This research represents the basis for a future work, that will end up with the elaboration of a System Dynamics model that will provide insight regarding the dynamics of short life cycle products, such as fashion goods or electronic devices, with the goal of proposing innovative solutions
The maintenance management in the highway context: A system dynamics approach
No full textBeing a complex process and a predominant cost component, the maintenance management represents, for the highway context, one of the most critical aspects to take into account for a company concessionaire of the highway service. This is even truer for difficult environments, such as the mountain one, where the particular geographical features requires stricter and more expensive maintenance plans. The paper presents a real case study on the management of the maintenance operations for the A32 highway, which links the city of Turin with France, passing through the mountain range of Alps in the Italian territory. Utilizing a system dynamics (SD) approach enabled by the Powersim software, a model of the particular maintenance system has been created and implemented. Moreover, an optimization of the number of working yards, of the costs related to the total expenses of maintenance with particular regards to the penalties due to a failed respect of the imposed constraints, has been put into place. In order to efficiently manage in real time the complex implemented model, an opportune decision cockpit has been developed and connected to a vast database filled with continuously updated data
Literature review about supply chain vulnerability and resiliency
No full textThis paper focuses on the literature review regarding the vulnerability of supply chains and the relative resiliency. After identifying the most common threats (that can have high or low probability of occurrence) that affect the supply chain integrity, some best practices from real cases are provided in order to provide the key factors to build a resilient supply chain. This research represents the basis for a future work,
that will end up with the elaboration of a System Dynamics model that will provide insight regarding the dynamics of short life cycle products, such as fashion goods or electronic devices, with the goal of proposing innovative solution
Using system dynamics for short life cycle supply chains evaluation
No full textThis work is part of an Italian National Research Project embracing different aspects of a short life-cycle products supply chains: its modeling, its resiliency and its competitiveness. In fact, this particular kind of
products, like fashion goods, toys or electronic devices, have different characteristics compared with long-medium life cycle products and this implies a quite different management as well as competitiveness
factors to take into account. Starting from the modeling of a supply chain of this kind, utilizing the Powersim Studio Software implementing the System Dynamics methodology, with the goal of showing its
behavior under specific scenarios, some vulnerability causes have been considered in order to make the supply chain more resilient. Finally, the competitiveness dynamics between two companies producing
short life cycle items has been modeled and analyzed
Design of experiment and montecarlo simulation as support for gas turbine power plant availabilty estimation
No full textMaintenance is an important aspect in order to guarantee the efficiency of industrial facilities. For power plants the high availability ratios can be obtained only with preventive maintenance but the result costs increases rapidly. In order to reduce the cost level of the maintenance activity, on-condition maintenance is carried out on an increasing subset of components. Only using appropriate reliability models can identify the optimal mix between preventive and on-condition maintenance. Some time the data required by such models are inadequate or missing and the performances of the implemented system can fall quite rapidly. The authors propose an innovative approach based on a hierarchical Montecarlo simulator able to estimate properly the power plant reliability and, at the same time, improve its performances by a fine-tuning of its parameters. A real life case study is than presented and discussed
A system dynamics approach for managing the LNG procurement for an offshore platform feeding a power plant
No full textThe purpose of this study was the development of a simulation model to verify the logistic feasibility of the construction of a new regazification offshore terminal feeding a power plant located in Africa, subjected to a possible future doubling. In particular the model was used to test the proper supply of LNG (Liquefied Natural Gas) in the power plant real operating conditions and with particular reference to certain sizing configurations of vessels involved (dimensional range for tank buffer, shuttle ship size range). The model, taking into account sea conditions data available on site, extensively characterized during the oceanographic studies made, and with reference to defense works type realization and preliminary sizing (and specifically the breakwater dam and the its effect on the perturbation conditions in the proximity of the ship's mooring points) has assessed the risk of the power plant supply failure and the consequent lack of production (Unavailability of LNG or shut down). Moreover, the model estimated, for the scenarios simulated, the residence berthing times, the maximum frequency of unloading and the mooring / unmooring frequency reachable
Design of experiment and montecarlo simulation as support for gas turbine power plant availabilty estimation
No full textA system dynamics approach for managing the LNG procurement for an offshore platform feeding a power plant
No full textThe purpose of this study was the development of a simulation model to verify the logistic feasibility of the construction of a new regazification offshore terminal feeding a power plant located in Africa, subjected to a possible future doubling. In particular the model was used to test the proper supply of LNG (Liquefied Natural Gas) in the power plant real operating conditions and with particular reference to certain sizing configurations of vessels involved (dimensional range for tank buffer, shuttle ship size range). The model, taking into account sea conditions data available on site, extensively characterized during the oceanographic studies made, and with reference to defense works type realization and preliminary sizing (and specifically the breakwater dam and the its effect on the perturbation conditions in the proximity of the ship's
mooring points) has assessed the risk of the power plant supply failure and the consequent lack of production (Unavailability of LNG or shut down). Moreover, the model estimated, for the scenarios simulated, the residence berthing times, the maximum frequency of unloading and the mooring / unmooring frequency reachabl
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