Ballast water management: technology choice comparing TODIM and THOR 2

Abstract

This paper approaches the problem of ballast water treatment in ships. This has been identified as one of the four greatest threats to the world’s oceans. Solutions that have been considered for solving the problem are alternative water treatment technologies. In the case study reported in this paper three major water treatment technologies have been evaluated with the help of twenty-six criteria, quantitative as well as qualitative by using two discrete multicriteria methods, TODIM and THOR 2. The THOR 2 consists of the axiomatic evolution of the THOR method and both THOR 2 and THOR are made available through the THOR Web platform. Five groups of evaluation criteria are then considered: practicality; biological effectiveness; cost/benefit ratio; time frame for the implementation of standards; and environmental impact of the process' sub-products. In this paper a case study on choosing a ballast water treatment technology is presented. Three alternative ballast water management technologies are proposed by experts in the field and are evaluated with the help of twenty-six criteria, quantitative as well as qualitative. Each ballast water management method is described by a list of twenty-six attributes or criteria. After setting the problem in a clear way and consulting different experts, the two separate applications of both TODIM and THOR 2 are performed. What is denoted as Management Method #1 is indeed chosen as the best alternative according to both methods. The conclusion is that those two methods, although conceptually and analytically quite different, lead essentially to the same main results. Two other applications of both TODIM and THOR have indeed confirmed the convergence of results in spite of the conceptual and technical differences between the two methods. This suggests that formulating a decision problem in a correct, clear-cut way can be at least as important as the technical characteristics of the method per se.

Waste Reduction Using the Thor 2 Hybrid Method: Decision Making in the Context of Lean Healthcare

“…Therefore, the purpose of this paper is to prioritize which waste should be treated by LH in a medical clinic of a middle-sized Brazilian hospital using the MCDA method THOR 2 (Hybrid Multicriteria Decision Support Algorithm for Decision Processes with Discrete Alternatives). The method has been applied in several problem situations (Santos et al, 2022;Esteves et al, 2022;Gomes et al, 2021;Tenorio et al, 2021).…”

“…This methodology has the advantage, in relation to probability in statistics, that it does not require a preliminary database. (Cardoso et al, 2009) (Gomes et al, 2010) (Gomes et al, 2021) (Pawlak, 1982.…”

Multicriteria decision making applied to waste recycling: comparison between THOR and THOR 2 methods

“…The THOR 2 method, developed by Tenório (2020), consists of the axiomatic evolution of the THOR method by Gomes (1999). The originally developed method combines Rough Set Theory, Fuzzy Set Theory and Preference Theory (Gomes et al, 2008(Gomes et al, , 2021Costa et al, 2020).…”

“…In scenario S2 ( 5), more flexible than S1 (4) and stricter compared to S3 ( 6), the sum of the weights of criteria "j" such that "a" is strongly preferred to "b" and is weakly preferred "b" is greater than the sum of weights of criteria "j" such that "a" is weakly preferable to "b" plus the sum of weights of criteria "j" such that "a" is indifferent to "b" plus the sum of the weights of the criteria "j" such that "a" is not comparable with "b" plus the sum of the weights of the criteria "j" such that "b" is weakly preferable to "a" any plus the sum of the weights of criteria "j" such that "b" is strongly preferable to "a" (Gomes et al, 2021). Thus, the alternatives will only present punctuated attractiveness where Equations 1 and 3, aPb and aQb occur.…”

“…The term stands for Multicriteria Decision Aiding Hybrid Algorithm for Decision-Making Processes with Discrete Alternatives (THOR). Since its inception, the THOR method has been applied in various contexts, such as: demand Prioritization on Supply Chain (Esteves et al, 2022); strategy Analysis for project portfolio evaluation in a technology consulting company (Santos et al, 2022); military ship selection (Tenório et al, 2020;Costa et al, 2020); choice of electronic payment models for credit cards (Gomes & Maia, 2013); technology selection, with its results compared to the TODIM method (Gomes et al, 2021); and notably, in sustainable issues applied to waste recycling (Gomes et al, 2008).…”