Corinne Curt

Fuzzy concepts applied to food product quality control: A review

Fuzzy logic is now a wide field of study and different tools have been developed over the last 10 years. Its implementation in food quality control for the food industry has been highlighted by several authors that have focused on different applications designed specifically for this task. This is especially true in the case of taking into account the reasoning process, expressed in linguistic terms, of operators and experts. Nevertheless, applications are still limited and few reviews on this topic are available. Consequently, the aim of this paper is to provide an overview of the application of fuzzy concepts to the control of the product quality in the food industry over the past 10 years. Future interesting developments and trends in this area are also emphasized.

Dry sausage ripening control integration of sensory-related properties

A feed-forward control algorithm is proposed to ensure the constancy of the sensory quality of the dry sausage during its fermentation. Fermentation is carried out with industrial equipment. The algorithm is based on human skill: the input variables of the controller are sensory evaluations made close to the line by the operators and the human diagnosis has been modeled using fuzzy logic. An experimental validation is introduced: the results show that the algorithm is likely to be able to control the process so as to obtain the desired sensory characteristics at the end of the fermentation stage. A user interface has been implemented in order to help the operator to cope with process control.

Évaluation des ouvrages hydrauliques de génie civil

This paper reviews Cemagref (Centre national du machinisme agricole, du genie rural, des eaux et des forets) research on assessment of hydraulic works, especially on their performance and safety. A generic functional model has been developed, using reliability methods, to represent the various mecanisms acting on different hydraulic works (gravity and embankment dams, fluvial dikes, etc.). Collecting and analyzing data on the failure of these works allowed us to define structural indicators and the rules for their assessment. Performance indicators for hydraulic works were created through multicriteria aggregation methods; various results were thus obtained. A database of knowledge relating to mechanisms and histories of dam ageing has been produced and constitutes a useful aid for consulting civil engineers. Methods and tools have been developed to assess the performance of fluvial dikes and to assist managers in planning maintenance operations. Similar research is under way on embankment dams and will p...

A method for the analysis and control of sensory properties during processing––application to the dry sausage process

The sensory quality of a food comes from the combination of a set of parameters concerning all the steps of product life, from the raw materials to the conditions of preparation at home. We focus on manufacturing conditions and propose a method for the control of a set of sensory properties and defects whose variations must be kept within prescribed tolerances. This method entails, firstly, the identification of causes of variations of sensory quality, i.e., the definition of the scenarios leading to defects or faulty properties; secondly, the determination of control methods used by the factory, i.e., the corrective actions used to avoid or eliminate a defect or a deviation of a sensory property; and thirdly, the proposal of a strategy for improving sensory quality control. The method is illustrated by dry sausage manufacturing in two different factories. In both, the method enables proposing the improvement of sensory quality control, i.e., by a formal description of the skill concerning process control possessed by operators. A control system based on this formalized knowledge was implemented.

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...

Formalization of at-line Human Evaluations to Monitor Product Changes during Processing: The Concept of Sensory Indicator

Sensory characteristics of food products are essential for consumers. It is a challenge for firms to maintain these characteristics constant, with as few variations in quality as possible. The control of quality properties and in particular sensory ones can be carried out using reliable process control strategies. Nevertheless, classical control approaches can rarely be used in food processes due in particular to the lack of real-time, reliable instrumental sensors, which limits available information on the product, and to poor understanding of the interactions between food and process. The scarcity of suitable on-line sensors is closely related to the variability of the raw material, the complexity of the biological phenomena during processing and the severe constraints that sensors must satisfy, such as hygiene, high humidity, and so on. As a consequence, some food product properties are very difficult to be quantified during food manufacture [11]. However, various solutions have been explored to overcome this problem: sensor design and adaptation, off-line measurements, software sensors [21]. Moreover, human evaluation is widely accepted as a tool for the evaluation of the quality of food products: operators play a major role in process control, since they take into account not only the information from sensors but also that from their own senses [20]. They can detect small changes in product characteristics such as cookie color after baking [12] thanks to their process knowledge and experience.

The Fuzzy Symbolic Approach for the Control of Sensory Properties in Food Processes

End products must conform to the characteristics defined in their specifications. These characteristics include sensory properties, which are essential because they influence the choice and the preference of consumers. It is important to take them into account for their control when manufacturing products. Therefore, in food industry, these properties must be controlled close to the manufacturing line by implementing adapted measurement and process control.

Multimodel-Based Diagnosis of Hydraulic Dams

AbstractA dam diagnosis method based on a multimodel approach is proposed, and structural, functional, behavioral, and perception models are defined. The modeling process treats a dam as a connecte...

Hydraulic Dam Safety Assessment with the Timed Observations Theory

The safety control process of industrial systems (considered to be dynamic systems) needs to take in account physical processes (e.g. building ageing), informational processes (data collection and processing), decisional processes (data aggregation), and has to consider various constraints (e.g. economic and regulatory). The improvement of informational and decisional processes with the aim of controlling physical processes is based on the development of models and algorithms for measurement, assessment, control, diagnosis and prognostic. In the domain of dam management, assessment of reliability and safety, fault diagnosis, and corrective action proposals are carried out by expert engineers during dam reviews. With the perspective to assist these expert engineers, it is of great importance to develop methods and tools to manage the dynamic behaviour of dams and to model the processes at the same level of abstraction that is used by experts. In this chapter, the authors tackle the cognitive process of the diagnosis by means of a formal multi-modelling method and a diagnosis algorithm. The multi-modelling method called Timed Observations Method for Diagnosis (TOM4D) is based on the elaboration of four models: a Structural Model describing the relations between the components of the system, a Functional Model providing the relations between the values of the process variables (i.e. a set of mathematical functions), a Behavioural Model defining the states of the process and the discrete events firing the state transitions, and a Perception Model composed of a set of abstract variables, a set of thresholds associated to these variables and a set of constraints. The resulting process allows the automatic fault detection, identification and diagnosis and it is applied to hydraulic dam safety.