Aurélie Talon

Selection of appropriate defuzzification methods

We propose an approach for selecting appropriate defuzzification methods that fulfills the requirements of a group of experts.We propose a sensitivity analysis of defuzzification methods.We apply this approach to the assessment of dam performance.Methods were chosen in relation to the objectives (decision-support and communication) defined by a group of dam experts.The approach is applied to a real case. The performance assessment of dams is of major importance for optimizing maintenance management. A methodology is provided here to assess the risk of dam failure using data collected during in-situ inspections and from the design and follow-up files. This assessment takes into account uncertainty associated with the data and the assessment process. The result of this assessment is introduced in a fuzzy frame. This paper presents the approach taken to choose defuzzification methods that allow extracting the information necessary from this possibility distribution so that dam experts can both rank dam maintenance actions and communicate the results of this assessment.This paper first presents the process used to assess dam performance after which it presents the defuzzification methods available. A sensitivity analysis is then performed to select the methods most relevant for our case study. The last part presents the development of a tool useful for the application of defuzzification methods to our problematic and describes a real case study in which the selected defuzzification methods are used.

Assessment and Control of the Quality of Data Used during Dam Reviews by Using Expert Knowledge and the ELECTRE TRI Method

AbstractGenerally, experts use very large quantities of data during the analysis of civil works. These data are of four main types: visual observations, monitoring data, data calculated from models, and design and construction data. They are frequently “imperfect”: they contain uncertainty, imprecision, incompleteness. These imperfections have various roots, for instance, material location and sampling, number of measurement instruments, maintenance, such as scraping downstream slope, and frequency of monitoring measurement, etc. The method proposed in this paper first permits the identification of the various sources of imperfection and their definition as criteria; second, it provides a reliable way of assessing these criteria; third, it applies the multicriteria analysis ELECTRE TRI method to aggregate the values resulting from the assessment of the criteria. Finally, corrective actions are proposed to maintain or replace the measurement system under standard operating conditions. The method was applie...

Service-life assessment of building components: application of evidence theory

This paper deals with the assessment of the service life of in-service building components subjected to known environmental and usage conditions. This assessment is complex because of two primary features. First, the assessment has to be carried within a multiscale context: a geometric scale that ranges from the material or elemental to building scale; a range in the complexity of the degradation (phenomena that varies from a single phenomenon to the consideration of several degradation scenarios); a range of possible performance requirements, from one function to several; and consideration, as well, to the time over which the process is carried out that may span from the design stage to that of management and repair. Second, this assessment must also take into consideration the availability and features of service-life data that by nature is heterogeneous, imprecise, uncertain, and incomplete. In this context, a comprehensive methodology is developed using all available data on service life derived from ...

Mechanical investigation of tunnels: risk analysis and notation system

The current mechanical investigation strategy applied to RATP (Régie Autonome des Transpots Parisiens) tunnels is mainly based on visual inspection. All the works are inspected and every apparent fault is located and reported in inspection reports. However, this type of inspection detects only apparent faults without linking them to their causes. A new methodology of mechanical investigation is proposed in the framework of the ANR project MEDITOSS (Méthodologie de Diagnostic des Tunnels et Ouvrages Souterrains en Service), consisting in integrating mechanical investigation tools to better characterise the geometrical and mechanical state of the tunnel. This new strategy combines four techniques (ground penetrating radar, light dynamic penetrometer, endoscopy and geo-mechanical impedance). These techniques are applied to panels to obtain a ‘panel score’. This paper presents a risk analysis of the system studied (network of corridors and tunnels), by applying the bow-tie method in order to obtain information on its elements, its function and its pathologies. This analysis incorporates a quantitative characterisation method (scoring) to assess the state of corridors and tunnels. These methods are tested on infiltration and cracking pathologies for the risk analysis and on the notation of a corridor for the quantitative quantification.