Marcele Elisa Fontana

Modelo para setorizar redes de distribuição de água baseado nas características das unidades consumidoras

In addition to incurring direct costs, the occurrence of breaks in a water distribution network always has associated social consequences, mainly related to the interruption of water supply during infrastructure repair. In these cases, network segmentation facilitates maintenance activities. However, the Brazilian norms, about network segmentation, relate only the technical guidelines that must be followed. We therefore propose network segmentation based on the impact intensity caused by a lack of water in each pipe segment. To measure this impact, we propose a priority index that aggregates the characteristics of consumer units by the SMARTER multicriteria method. Taking this index into account, we propose a segmentation model for water distribution networks that seeks to maximize the benefits generated and to minimize the number of isolation valves.

Strategic Options Development and Analysis to identify criteria to evaluate segmentation problems of a water distribution network

Due to ageing and depreciation of the water distribution network components, leaks and ruptures are common on the water network. These problems can cause the water loss, sometimes the water contamination and the discontinuity in water supply, due the supply interruption during the infrastructure repair, as well as reduction of available water in the system, causing the users to be dissatisfied. To perform maintenance is necessary to close part of the water distribution network and its process is called network segmentation. However, several aspects (criteria) must be evaluated for the efficient allocation of segmentation valves. Therefore, this paper proposes the use of the Strategic Options Development and Analysis to survey criteria to evaluate alternatives for segmentation of water distribution network.

Using the Efficient Frontier to Obtain the Best Solution for the Storage Location Assignment Problem

The main variables that influence the efficiency of a warehouse are the use of space and the order picking distance. In the literature, there are proposals to add the costs with space and order picking in order to evaluate each alternative for storage location assignment. However, there were problems with the adoption of this methodology, including difficulties in determining the costs and tradeoffs between them. These difficulties can result in solutions that are suboptimal. Based on these facts, this paper proposes a class-based storage process and storage location assignment by a cube-per-order index (COI) that analyzes the space required and the total order picking distance by Pareto-optimal calculations. The efficient frontier possibilities allow the reduction of the set of alternatives, and the DM can analyze only the alternatives on efficient frontier.

Water distribution network segmentation based on group multi-criteria decision approach

A correct Network Segmentation (NS) is necessary to perform proper maintenance activities in water distribution networks (WDN). For this, usually, isolation valves are allocating near the ends of pipes, blocking the flow of water. However, the allocation of valves increases costs substantially for the water supply companies. Additionally, other criteria should be taking account to analyze the benefits of the valves allocation. Thus, the problem is to define an alternative of NS which shows a good compromise in these different criteria. Moreover, usually, in this type of decision, there is more than one decision-maker involved, who can have different viewpoints. Therefore, this paper presents a model to support group decision-making, based on a multi-criteria method, in order to support the decision making procedure in the NS problem. As result, the model is able to find a solution that shows the best compromise regarding the benefits, costs, and the decision makers’ preferences.

Decision model to control water losses in distribution networks

The losses in the urban water supply networks have become a growing concern. There are several alternatives for the quantification, detection and monitoring of water losses. However, in general, water companies have budgetary and other constraints that hinder implementation. Therefore, this paper presents a model to aid the selection of a subset of preventive maintenance actions to control water losses while accounting for the water companies’ restrictions. The model combines an additive multi-attribute value analysis by applying the SMARTER method to evaluate alternatives with Integer Linear Programming (ILP). The model shows to be efficient in order to achieve a portfolio of preventive maintenance actions, particularly when the decision maker considers that, there is a compensation for attribute evaluations.

Group Decision Model to Support the Survey of Alternatives Applied for Participatory Democracy

Participatory democracy has been used in Brazil, and other countries in the world, as a form of social participation in the municipalitys administration. In this sense, Participatory Budget (PB) is a government initiative to expand community participation in decision making on the public budget. However, the procedure normally used to survey the alternatives can lead to errors such as: (1) the alternative selected is not technically appropriate for its implantation, (2) the alternative is insufficient to solve the problem, etc. Therefore, for in order to solve these problems, this paper proposes a group decision model to support the survey of alternatives in PB. This model consists of three basic steps: (1) survey of the problems from the community, (2) suggestion of a set of alternatives to solve these problems and (3) definition of the subset of these alternatives. We applied the Strategic Option Development and Analysis (SODA) in order to understand the problem and it was observed that voters have more facilities in electing problems than solutions.

Analyzing Conflicts between Decision-Makers in Determining Criteria to Evaluate Segmentation in Water Distribution Network

In water distribution networks, maintenance activities to insulate pipes with isolation valves are common. From that perspective, the ideal situation would be to have one valve on each pipe end in order to insulate each pipe without impacting the whole network. However, the allocation of valves has a high cost and pipes become weaker next to valves thus increasing the deterioration indexes. Therefore, it is necessary to support decision-making on the number of valves and their allocation in the network. This process is usually made in a non-structured manner, especially when defining which criteria should be applied to evaluate network conditions. Furthermore, a group of decision-makers normally take part in this process with different points of view. So, in this paper we propose a model for capturing different perspectives from decision makers using cognitive maps and analyzing conflicts between them in order to enhance the decision-making process and promote resolution of existing conflicts.

ANALYSIS ON THE APPLICATION OF INVESTMENTS IN WATER LOSSES IN NORTHEAST BRAZIL

The sanitation situation across Brazil is considered calamitous. Due to the geographical characteristics of the Northeast region, the water found in this state needs to be harnessed to the fullest. One way to achieve this goal is through the control of water loss. The present study aimed to evaluate how much of the investment in the water sector is reflected in reduced losses. More specifically the objectives were: (1) Collect information and investment losses in the water sector in the Northeast region; (2) Perform diagnosis of loss of water in the Northeast; (3) Perform statistical analysis. By examining the high rates of loss, it is evident that increased investments in large projects for increased capture of water resources is the focus of the companies, while the proper management of the losses, with which the northeastern states could avoid constant dependence on climate, is not treated as a primary goal.

A multi-criteria decision making approach to balance water supply-demand strategies in water supply systems

Paper aims: this paper proposes a model to aid a group of decision makers to establish a portfolio of feasible actions (alternatives) that are able to balance water supply-demand strategies. Originality: Long periods of water shortages cause problems in semi-arid region of northeast Brazil, which affects different sectors such as food, public health, among others. This problem situation is intensified by population growth. Therefore, this type of decision making is complex, and it needs to be solving by a structured model. Research method: The model is based on a problem structuring method (PSM) and a multi-criteria decision making (MCDM) method. Main findings: Due to society and government influences, the proposed model showed appropriate to conduct a robust and well-structured decision making. Implications for theory and practice: The main contributions were the study in regions suffering from drought and water scarcity, as well as the combination of PSM and MCDM methods to aid in this problem.

MODELO MULTICRITÉRIO DE APOIO À DECISÃO ENTRE COMPRAR E REUTILIZAR EMBALAGENS: UM ESTUDO DE CASO

Tem sido crescente a utilização da logística reversa como forma de diferencial competitivo por empresas em todo mundo. Mas, a decisão de adotá-la ou não vai de encontro a antiga visão que restringia a análise apenas ao critério custo, pois, com o passar do tempo e as suas mudanças surgiram novos critérios, o que faz com que fique muito mais difícil de se tomar tal decisão. Dessa forma, como envolve múltiplos critérios, faz-se necessária a utilização de um método formal de apoio à decisão que viabilize o sucesso na escolha. Portanto, este artigo propõe a utilização de um método multicritério que auxilia o decisor de uma empresa do ramo de metalurgia e siderurgia sobre a reutilização ou compra de novas embalagens para seu processo produtivo.