Chakhar, Pusceddu & Saad - input2012
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Chakhar, Pusceddu & Saad - input2012

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Salem Chakhar, Clara Pusceddu and Ines Saad on "Evaluating Post-Accident nuclear risk by coupling GIS and rough set theory"

Salem Chakhar, Clara Pusceddu and Ines Saad on "Evaluating Post-Accident nuclear risk by coupling GIS and rough set theory"

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    Chakhar, Pusceddu & Saad - input2012 Chakhar, Pusceddu & Saad - input2012 Presentation Transcript

    • Input2012 - Cagliari 11 May 2012 - EVALUATING POST-ACCIDENT NUCLEAR RISK BY COUPLING GIS AND ROUGH SET THEORY1 Salem Chakhar University of Laval, Canada Clara Pusceddu University of Sassary – Faculty of Architecture of Alghero, Italy Ines Saad, University of Picardie, France
    • INTRODUCTION The management of the consequences of a major nuclear Input2012 - Cagliari 11 May 2012 accident necessarily involves the consideration of multiple criteria in order to ensure sustainable development in areas that might be affected. Cagliari 11 May 2012 Furthermore, the management of the consequences of a major nuclear accident requires a multidisciplinary approach to produce a sustainable response to the environmental, economic and social problems linked to the various local intricacies. 2
    • OBJECTIVE Propose a Multicriteria Evaluation approach for Input2012 - Cagliari 11 May 2012 characterizing the different districts of the affected area in terms of their vulnerability levels while taking into account multiple stakeholders with contradictory objectives and Cagliari 11 May 2012 priorities. The proposed approach is composed of 4 phases: 1. identifying the stakes involved, 2. identification of representative criteria, 3. quantifying criteria scores, and 4. group multicriteria classification. 3
    • FOCUSING ON 4 PHASE…. (CHAKHAR…) It requires the use of an adequate technique to combine the Input2012 - Cagliari 11 May 2012 perspectives of different stakeholders. We adopted the output-oriented strategy (Dias and Cagliari 11 May 2012 Climaco, 2000) to combine these perspectives. This strategy works as follows: 1. first, each stakeholder performs her/his individual classification; then 2. an appropriate aggregation operator is used to combine the individual classifications into a collective one. 4
    • A DECISION SUPPORT SYSTEM DESIGN…. A decision support system supporting the proposed Input2012 - Cagliari 11 May 2012 approach has been developed by coupling GIS technology and Rough set theory (Pawlak 1991). Cagliari 11 May 2012 The approach is validated using real-world data relative to a nuclear risk management decision problem in the southern France. 5
    • IN THIS PRESENTATION ….1. Introduction of the proposed impact evaluation approach Input2012 - Cagliari 11 May 2012 Cagliari 11 May 20122. Presentation of the case study with some conclusion 6
    • 1. MULTICRITERIA IMPACT EVALUATIONAPPROACH Phase 1. Identifying the stakes involved Input2012 - Cagliari 11 May 2012 Phase 2: Identifying Cagliari 11 May 2012 representative criteria Phase 3: Quantifying criteria scores Phase 4: Group 7 multicriteria classification
    • 1. MULTICRITERIA IMPACT EVALUATIONAPPROACH Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 Identification of the stakes involved including everything that can be affected by an accident such as zones that are densely inhabited, business activities, and cultural and environmental assets. Then one or more adverse effects have to be linked to each stake so that they represent the consequences of an accident in various sectors. 8
    • 1. MULTICRITERIA IMPACT EVALUATIONAPPROACH Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 Once the various factors and adverse effects have been selected, the criteria that characterize them have to be identified. Formally, a criterion is a function qj, defined on a set of decision objects U (which are districts in our case), taking its values in an ordered set, and structuring the stakeholders preferences according to some points of view. The evaluation of an object u in respect to criterion qj is denoted qj(u). We denote by Q={q1, …,qm} the set of m evaluation criteria. 9
    • 1. MULTICRITERIA IMPACT EVALUATIONAPPROACH Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 This involves evaluating the consequences on each district in respect to each criterion. The output of this phase is an evaluation matrix where rows represent the districts and columns represent the evaluation criteria. Each box then contains the corresponding value of the criterion for the district in question. In terms of this phase, each district u will be associated with the vector (q1(u),…,qm(u)) which represents the evaluations of u with respect to the criteria in Q. 10
    • 1. MULTICRITERIA IMPACT EVALUATIONAPPROACH Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 The aim of group multicriteria classification phase is to assign the different districts of the study area to different risk classes while taking into account the perspectives of multiple stakeholders. A multicriteria classification model, called Dominance-based Rough Set Approach (DRSA) (Greco et al., 2002) an extension to rough sets theory (Pawlak 1991) to multicriteria classification, will individually be used by the different stakeholders. Some appropriate aggregation rules are then used to coherently combine the outputs of different stakeholders. 11 The DRSA is then used once again to obtain the final classification in terms of vulnerability/risk levels of the districts.
    • 4. CASE STUDY: NUCLEAR RISK MANAGEMENTDECISION PROBLEM The problem considered here concerns the management of post- accident nuclear risk in the southern France region. Input2012 - Cagliari 11 May 2012 This problem has been conducted during the PRIME project, Cagliari 11 May 2012 which is supervised by the French Institute for Radioprotection and Nuclear Safety. A full description of the project is available in Mercat-Rommens et al. (2010). The study zone covers a radius of some fifty kilometers around three nuclear sites in the lower Rhône Valley (the Cruas, Tricastin-Pierrelatte and Marcoule sites). 12
    • 4. CASE STUDY: NUCLEAR RISK MANAGEMENTDECISION PROBLEM The objective of the PRIME is to develop, conjointly with the experts, the stakeholders and representatives of the territory, a Input2012 - Cagliari 11 May 2012 multicriteria evaluation approach permitting to analysis and characterize the contaminated territory that will be useful for the managers of the risk. Cagliari 11 May 2012 Practically, the evaluation approach should associate to each district of the study area a degree representing the risk on this district of a nuclear accident resulting in releases into the atmosphere. For this purpose, a scale of six from 0 (for a situation described as normal) to 5 (in the event of a major and long-lasting negative impact) has been adopted by PRIME working team. 13
    • 4. CASE STUDY: NUCLEAR RISK MANAGEMENTDECISION PROBLEMThe table describes the vulnerability measurement scale Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 14
    • 4. CASE STUDY: APPLICATION. PHASE 1.IDENTIFYNG THE STAKES INVOLVEDThe stakes are organized into 3 groups: Input2012 - Cagliari 11 May 2012(i) radioecological consequences which are related to the contamination of urban, agricultural, costal and natural and Cagliari 11 May 2012 forest areas; Rhône River and ground water;(ii) economic consequences related to contamination and damage on companies, tourism activity, real estate and employment;(iii) population reactions. 15
    • 4. CASE STUDY: APPLICATION. PHASE 2.CHOOSING REPRESENTATIVE CRITERIA Based on the stakes identified in the previous phase, a comprehensive list of criteria has been identified by the different stakeholders (see Mercat-Rommens et al., 2010). Input2012 - Cagliari 11 May 2012 For the purpose of the present paper, only a subset of criteria, will be used for illustration. Cagliari 11 May 2012 16
    • 4. CASE STUDY: APPLICATION. PHASE 3.QUANTIFYING THE CRITERIA SCORES The quantification of criteria required the federation of available radio-ecological data (field data, modeling, experimental results), as well as territory data. Input2012 - Cagliari 11 May 2012 The assessment method of the radiological sensitivity indicators invoked classic impact calculation models for radionuclides used at Cagliari 11 May 2012 the IRSN: CASTEAUR code for river discharges (see Duchesne et al., 2003), ASTRAL code for forest ecosystem and food chain contamination following accidental radioactive pollution (see Renaud et al., 1999; Calmon and Mourlon, 2005), integrating the spatial variability of parameters. 17
    • 4. CASE STUDY: APPLICATION. PHASE 3.QUANTIFYING THE CRITERIA SCORESAn extract of the obtained evaluation matrix that represents a commoninformation table for all the involved stakeholders for the 4 phase. Input2012 - Cagliari 11 May 2012 18 districts (x1,…..x18) have been carefully selected (from 491 Cagliari 11 May 2012 districts) by PRIME working team: these districts are chosen to be as representative as possible by including urban, industrial as well as rural districts. 18
    • 4. CASE STUDY: APPLICATION. PHASE4. GROUP MULTICRITERIA CLASSIFICATION Individual classification Given the evaluation of the 18 selected districts in respect to all criteria, each Input2012 - Cagliari 11 May 2012 stakeholder is called to classify each of them on the global vulnerability scale. The responses of the stakeholders are then used to define the values of the decision attributes E1, E2 and E3 associated with the 3 stakeholders considered Cagliari 11 May 2012 in this paper. Then each stakeholder should apply the DRSA on each decision table to get its own classification. Aggregation of the individual classification Final classification 19
    • 4. CASE STUDY: APPLICATION. PHASE 3.QUANTIFYING THE CRITERIA SCORES Input2012 - Cagliari 11 May 2012 Cagliari 11 May 2012 20
    • 4. CASE STUDY: APPLICATION, 4. GROUPMULTICRITERIA CLASSIFICATIONAggregation In this step, we first apply the aggregation procedure to construct a common decision table with common Condition Input2012 - Cagliari 11 May 2012 attributes (Criteria) and Decision Attributes. Cagliari 11 May 2012Final classification Next, the Dominance-based Rough Set Approach (DRSA) is applied to the common decision table to classify the districts of the study area. 21
    • 4. CASE STUDY: APPLICATION, 4. GROUP MULTICRITERIA CLASSIFICATION The result of classification is shown in Figure 1. The left- hand side of the interface shows the Input2012 - Cagliari 11 May 2012 global vulnerability scale with shaded tones. The map on the right- hand side of the interface shows the final classification of the Cagliari 11 May 2012 different districts. It is easy to see that vulnerability decreases relatively concentrically around the Tricastin- Pierrelatte nuclear site, which is the location of the fictive accident considered in this case study.The obtained risk map represents the main decision support that could be 22used by risk managers to effectively and rapidly manage the contaminateddistricts by appropriately identifying the required measures for affecteddistricts