Marcelo Hazin Alencar

Multicriteria and Multiobjective Models for Risk, Reliability and Maintenance Decision Analysis

Multiobjective and Multicriteria Problems and Decision Models.- Multiobjective and Multicriteria Decision Processes and Methods.- Basic Concepts on Risk Analysis, Reliability and Maintenance.- Multidimensional Risk Analysis.- Preventive Maintenance Decisions.- Decision Making in Condition-Based Maintenance.- Decision on Maintenance Outsourcing.- Spare Parts Planning Decisions.- Decision on Redundancy Allocation.- Design Selection Decisions.- Decisions on Priority Assignment for Maintenance Planning.- Other Risk, Reliability and Maintenance Decision Problems.

The problem of disposing of plaster waste from building sites: Problem structuring based on value focus thinking methodology

Plaster is a material which is widely used in Brazil on construction sites. However, its use in recent years has been limited by a legal resolution on the environment introduced in Brazil. One of the regions most affected by these restrictions is the Northeast where the strategic importance of plaster for the region is apparent from the extensive economic development, centered on the gypsum pole of Araripe in the state of Pernambuco. This problem has involved many interested parties, among whom are plaster producers, plastering companies, builders, unions (for plaster workers, and construction workers), Town Halls, and so forth. Therefore, there is a need to structure the problem with a view to obtaining a better understanding of the problem given the lack of information on the real decision problem. To reach this objective, value focus thinking (VFT), a methodology that addresses how values can be used to improve the decision making process, was applied and the problem was structured. Thus, it was possible for the parties involved to clarify their objectives, and specify more precisely the consequences and constraints for the decision problem. In addition, each party involved could get a better understanding of their own wishes. In conclusion, the VFT methodology application enables the parties involved to make more consistent decisions, and therefore to ensure that plaster will continue to be used in the construction industry.

Delay-time inspection model with dimensioning maintenance teams

We propose a inspection policy based on the delay time concept.We consider the number of maintenance teams for emergency demands as a decision variable.We illustrate the use of the model in a real situation involving a lessee and a leasing company.We highlight the practical impacts of the model by calculating different scenarios (parameters).We highlight the contribution provided by the proposed model. Due to the increase in using equipment in various construction activities, planning the maintenance of this equipment has become extremely important as this aids meeting project deadlines. Alternatively, builders can lease equipment, an option that, in addition to having the advantage of gaining access to the best available technologies at feasible cost, also benefits from the fact that providing maintenance is a contractual obligation of the lessor company. In this context, it must establish a maintenance policy to support the lessee company at an acceptable cost. Thus, this paper proposes a policy for developing an inspection program and forming inspection and maintenance response teams. The application of these concepts targets supporting maintenance planning by equipment-leasing companies in the construction industry.

Multicriteria Model to Support Maintenance Planning in Residential Complexes under Warranty

AbstractBuilding-maintenance decisions are a challenge for most builders. When builders finish construction, there is a guarantee period during which maintenance is their responsibility. These decisions have an effect that go beyond the financial aspects of maintenance costs, because failures during the warranty period are reflected in customer satisfaction and may have an effect on future sales. Thus, maintenance strategies should be devised with a focus on how to best deploy them to optimize both savings and occupant satisfaction. For this purpose, the present paper proposes a multicriteria model based on the delay-time concept to provide the builder with a quantitative tool to support the definition of a maintenance-inspection policy. An illustration of the application of the model is demonstrated, providing good results that support the decision maker in setting a better inspection policy.

A Multicriteria Decision Model for Assessment of Failure Consequences in the RCM Approach

This paper proposes a multicriteria decision model based on MAUT (Multiattribute Utility Theory) incorporated into an RCM (Reliability Centered Maintenance) approach in order to provide a better assessment of the consequences of failure, allowing a more effective maintenance planning. MAUT provides an evaluation of probability distributions on each attribute as well as trade-offs involving lotteries. The model proposed takes advantage of such evaluations and it also restructures consequence groups established in an RCM approach into new five dimensions. As a result, overall indices of utility are computed for each failure mode analyzed. With these values, the ranking of the alternatives is established. The decision-maker’s preferences are taken into account so that the final result for each failure mode incorporates subjective aspects based on the decision-maker’s perceptions and behavior.

Multidimensional risk evaluation of natural gas pipelines based on a multicriteria decision model using visualization tools and statistical tests for global sensitivity analysis

Multidimensional risk analysis in pipelines has been addressed in the literature in recent years which has led to a greater understanding of risk in the decision context. A risk assessment model based on different perspectives becomes attractive to decision-makers (DMs) who are responsible for the maintenance of pipelines, and can help to prioritize maintenance efforts, and therefore optimize the use of human financial and other resources. As to the transportation of gas by pipeline, efforts at risk analysis must consider the physical and operational characteristics of the product, failure modes and their consequences, based on each accidental scenario considered. Different parameters are collected and/or estimated in order to produce a recommendation for the DM. Therefore, this paper enhances previous suggestions for a multicriteria decision model that evaluates multidimensional risk by using visualization tools and statistical tests as part of global sensitivity analysis. Simulations are made considering patterns which provide the DM with information about the uncertainty of different groups of parameters for the model. Furthermore, the output of the disturbance can be checked based on Kendalls correlation coefficient. Finally an evaluation can be made graphically of the different rankings of sections, thereby making a more assertive recommendation to the DM.

Adaptations to Possible Climate Change Impacts: Problem Structuring Based on VFT Methodology

This paper presents a research study, the objective of which is to generate alternatives to improve the urban infrastructure systems of Recife, capital of the Brazilian state of Pernambuco, and to develop the city’s adaptability to possible impacts of climate change. This city is always at risk from flooding and landslides caused by erosion of hillsides when heavy and/or prolonged rains occur. These cause destruction and deaths.

Decisions on Priority Assignment for Maintenance Planning

This chapter presents multicriteria (MCDM/A) models to classify and assign maintenance priorities in order to allow maintenance planning to be more effective. From traditional maintenance planning techniques such as RCM (Reliability Centered Maintenance), TPM (Total Productive Maintenance) and others, a common aspect of these techniques is the definition of maintenance priorities, based on a criticality classification for RCM, for example. As maintenance planning has to satisfy multiple objectives, such as availability, maintainability, detectability, safety and reliability besides cost, the maintenance manager is a decision maker (DM) who has to establish tradeoff amongst multiple criteria. This chapter presents an MCDM/A model integrated with the RCM structure using Utility Theory principles to include states of nature and the DM’s behavior to risk (prone, neutral and averse) in a decision model based on Multi-attribute utility theory (MAUT). To illustrate situations when a DM has a non-compensatory rationality, and requires an outranking method, a decision model based on ELECTRE TRI is applied. In addition, TPM aspects are discussed in order to emphasize potential MCDM/A problems that may be approached.

Decision on Maintenance Outsourcing

This chapter presents key aspects of multicriteria (MCDM/A) approaches for decisions on maintenance outsourcing regarding maintenance contract, which includes contract selection (e.g. repair contract) and supplier selection. Contract design is a multi-objective task that leads the maintenance manager (or decision maker - DM) to decide amongst a combination of contracts and suppliers’ bids for the service. Given the multiple objective nature of this kind of problem, this chapter presents models that include maintainability, dependability, quality of repair and other aspects besides cost. The decision models presented consider methods such as Multi-attribute utility theory (MAUT) to address compensatory preferences and ELECTRE for preferences that require an outranking method. The DM’s behavior to risk (prone, neutral and averse) is considered by using Utility Theory and Decision theory foundations in order to include the state of nature in decision models. Thus, most of the problems are related to supplier and contract selection, which may be modeled into a single problem when considering all combinations of contracts and suppliers as alternatives, including the possibility of in-house maintenance being undertaken by a maintenance service supplier. Depending on the organization and in how strategic its maintenance function may be, decisions in maintenance outsourcing may be approached in different stages. Thus, a key performance indicator (KPI) for such problems are defined depending on the type of organization, its capabilities and the number of maintenance activities, while the tradeoff amongst strategic objectives is balanced in order to assure the system’s availability.

Preventive Maintenance Decisions

Technological advances in equipment and the increase in process automation has led to the maintenance function having a role in business competitiveness. The contribution of preventive maintenance is discussed, as an important part of this function, with some emphasis on methods for planning replacement, in the sense of time interval of preventive maintenance. The classical optimization approach is used to illustrate the original preventive maintenance problem, thereby enabling insights and discussion of the main features that require the use of MCDM/A approaches for these decisions, and thus considering the multidimensional consequence space. A structured framework to build a multicriteria decision model for supporting the selection of time interval is presented. Two different MCDM/A methods are applied depending on the decision maker’s (DM) preferences. The first illustrates the application of Multi-attribute Utility Theory (MAUT) as an example of compensatory method and; the second details the application of a non-compensatory PROMETHEE method, which considers outranking relations.