Danielle Costa Morais

Using Promethee V to Select Alternatives so as to Rehabilitate Water Supply Network with Detected Leaks

The problem of the ageing infrastructure of urban water distribution networks and the loss of water associated with this has been one of the greatest infrastructure problems in urban areas. When a leakage is detected in the water supply network, problems arise when seeking to rehabilitate the network. Therefore, the decision problem is to choose which components to add or to improve and to maximize the benefits, which will result from the changes implemented. In addition, it is important to minimize costs, since water supply companies have limited budgets. Moreover, there are often several leakage points in the same water supply network and in the same period of analysis. Therefore, this paper puts forward a model for rehabilitating the greatest number of leakage points in a water network; it respects the constraints which a water company may have. Promethee V is used to assist the decision maker (DM) in selecting a set of feasible alternatives for rehabilitating the network from the criteria and the constraints set by the DM on the problem. For demonstration purposes, the proposed model was tested in a simulated network.

A multicriteria group decision model aggregating the preferences of decision-makers based on electre methods

Often decisions taken in organizations are made by a group of people, and in order to build a collective decision, the preferences of individuals must be considered. The two most useful approaches to aggregating individual preferences are the aggregation of individual judgments and the aggregation of individual priorities. This paper focuses on the latter approach and proposes a multicriteria group decision model in situations where there is no information with regard to the relative importance of the decision-makers. This model includes three stages. In the first, the ELECTRE II method is applied so as to obtain the individual rankings. In the second stage, a global matrix of alternatives versus decision-makers is built up using the results from the previous stage. Finally, the third stage aggregates the individual preferences by applying the ELECTRE IV method and the final collective evaluation is undertaken. A numerical application is presented to illustrate the model.

Priorização de áreas de controle de perdas em redes de distribuição de água

The water supply systems for its complexity and own characteristics embed a certain index of water losses in the production. Besides, an old infrastructure, common in the Brazilian water supply systems, propitiates an accelerated process of deterioration, giving as consequence larger maintenance problems, especially elevating the indexes of water losses due to the resulting effects of the negligence to the conservation activities. In consequence, the Water Companies have the problem of high revenue losses when wasting fresh water by lack of an appropriate management. Furthermore, the managers need a new posture front to the decision making process, regarding to the action to be implemented, for a better efficiency of the system operational control, in order to avoid the losses. The objective of this work is to present a multicriteria model based on the PROMETHEE I method to support the manager in ranking the critical areas of losses, seeking to allocate investment of time and resources in the water supply systems in a more efficient way, focus on its efforts in the most critical areas.

Modelo de decisão em grupo para gerenciar perdas de água

The planning of actions in supply systems, especially related to loss reduction and water wastage, usually involves groups or institutions with different objectives, responsibilities and interests. It also includes several alternatives to minimize the problem, mainly in terms of cost and performance, making the selection of the alternatives a complex task, requiring a specific methodology for treatment of conflicts. To contribute solve the problem, this study presents a multicriteria approach based on PROMETHEE method, proposing a model for group decision-making. Through an illustrative experiment, the employment of this approach is investigated with four decision-makers, representing financial, technical, environmental and social aspects. Thus, people responsible for sanitation division will have a different slant of the decision process, in relation to the action to be developed, for better operation and maintenance efficiency, managing losses.

Using value-focused thinking in Brazil

Value-Focused Thinking (VFT) provides a systematic approach to structure complex decisions for subsequent analysis. It is a powerful complement to decision analysis and its application has been growing in recent years. This paper discusses the application of VFT in Brazil to three problems in different contexts: water management, information system/information technology (IS/IT) strategic planning, and the disposal of plaster waste. This article describes how the VFT approach was used to structure these decision problems and identify alternatives to stall them, which led to developing qualitative and quantitative models for evaluating the alternatives, and discusses how such structures can be used in other similar problems.

PROMETHEE-ROC Model for Assessing the Readiness of Technology for Generating Energy

This paper puts forward a proposal for a multicriteria decision model for prioritizing technologies that are critical for power generation in the energy sector. It deals with the context of imprecise information regarding importance of criteria; then an integration of surrogate weights with the PROMETHEE method is undertaken in order to approach this context. In this type of strategic decision problem, how to deal with imprecise information is always a challenge. The use of surrogate weights presents a significant contribution and it can facilitate the assignment of weights in a decision ranking problem, which requires the decision-maker (DM) to order the criteria by their importance for the decision problem. Thus for this situation of assessing the readiness of technology for generating energy where the DM is able and feels comfortable to order all criteria by their relative importance, the proposed approach of surrogate weights in the PROMETHEE II method, the PROMETHEE-ROC model, is shown to be an adequate approach.

Using ELECTRE TRI to support maintenance of water distribution networks

Problems encountered in the context of the maintenance management of water supply are evidenced by the lack of decision support models which gives a manager overview of the system. This paper, therefore, develops a model that uses, in its framework, the multicriteria outranking method ELECTRE TRI. The objective is to sort the areas of water flow measurement of a water distribution network, by priority of maintenance, with data collected from an automated system of abnormalities detection. This sorting is designed to support maintenance decisions in terms of the measure more appropriate to be applied per region. To illustrate the proposed model, an application was performed in a city with 100 thousand water connections. With this model it becomes possible to improve the allocation of maintenance measures for regions and mainly to improve the operation of the distribution network.

A proposal for structuring and evaluating problems for participatory decision making in sanitation context

In Brazil, the cities disordered occupation has caused a huge deficit in the sanitation sector, with direct impacts on public health, becoming one of the major environmental problems. Therefore, in 2007, the Brazilian National Sanitation Law introduced the society participation in decisions regarding to the reduction of the sanitation problem, in order to get the population involved with the choice and the implementation of the alternatives for the problem. However, this participation is ill structured and many difficulties are found to achieve a final decision, besides, there is no specific model for this. So, the aim of this paper is to propose a group decision model based on two central themes: structuring and evaluating problem. The former is based on SODA (Strategic Options Development and Analysis) to improve the learning process and to identify the alternatives that could be implemented to reduce the sanitation problem. The latter is performed by Copeland method, which aid to rank those alternatives and to choose the one that represents the best society compromise. An illustration of the proposed model is shown in this paper, applying with three decision makers from sanitation sector.

Multicriteria Decision Making for Healthcare Facilities Location with Visualization Based on FITradeoff Method

This paper proposes an application of the Flexible Interactive Tradeoff (FITradeoff) method for siting healthcare facilities. The selection of the location of complex facilities, as hospitals, can be considered as a multidimensional decision problem for the several issues to be taken into account and, moreover, for the variety of stakeholders that should be involved. The case study under investigation is the location of “La Citta della Salute”, a new large healthcare facility in Lombardy Region (Italy). Starting from a cross disciplinary literature review, a multidimensional evaluation framework has been defined and applied to the case study by considering the point of view of one Decision Maker (DM). The application shows that a smaller effort is required from the DM using the FITradeoff method.

Aggregation cognitive maps procedure for group decision analysis

Purpose – Cognitive maps are used in group decision processes to structure problems. The problem structuring methods helps decision makers to improve the comprehension of the problem, identifying alternative actions and conflicts. However, represents the individual perceptions in a representative group decision into a single structure can be a complex task. The paper aims to discuss these issues. Design/methodology/approach – The objective of this paper is to improve the process of discussion, obtaining the interests and views of the participants and provide parameters to assist the analyst to guide the process. Furthermore, it is possible to analyze how participants are aligned or diverge from the group. The literature review presents some approaches for cognitive maps analysis, but there is a lack of structured methods to analyze them. This paper proposes a structure procedure for the aggregation of cognitive maps in three parts: workshop to generate individual maps, the aggregation of individual maps a...