DSpace Communidade:
http://repositorio.ufc.br/handle/riufc/22275
2024-03-19T08:30:34ZUm estudo sobre análise de eficiências usando análise envoltória de dados sob ambiente difuso
http://repositorio.ufc.br/handle/riufc/72439
Título: Um estudo sobre análise de eficiências usando análise envoltória de dados sob ambiente difuso
Autor(es): Barreto, Maria Aline Freitas
Abstract: Among the methodologies used to measure productive efficiency, Data Envelopment Analysis
(DEA) is one of the most commonly used not only in the literature but also in real world
applications. Therefore, a deeper study of this methodology becomes a crucial part in helping
Decision Making Unit (DMUs) to achieve productive efficiency. Classical DEA methods allow
us to measure efficiency, for the set being analysed, and classify the DMUs as either efficient
or as inefficient, while also allowing us to verify which efficient cases can be used as reference
for the inefficent cases. The use of Classic DEA models require precise data for both input
and output values. However, input and output values in the real world are usually imprecise,
approximate, or vague. One of the objectives of this work is to obtain a deeper knowledge of
the classical DEA methods and Fuzzy Data Envelopment Analysis (FDEA). Another objective
is to report a comparitive study between the classic DEA methods and the FDEA methods by
applying them to a set containing data from Brazil’s Northeast ports. Our results showed that
ports classified as efficient by classical DEA methods, including the ones used as reference
within the set, are not always classified as efficient by FDEA methods.
Tipo: TCC2020-01-01T00:00:00ZEscala Likert difusa: um estudo sobre diferentes abordagens
http://repositorio.ufc.br/handle/riufc/65678
Título: Escala Likert difusa: um estudo sobre diferentes abordagens
Autor(es): Monte, Lucas Gonçalves
Abstract: To analyze human attitudes is one of the key-points in Psychometric Scales. Being the most
known and used, the Likert Scale is commonly presented as a five-point or four-point rating
scale ranging from “strongly disagree” to “strongly agree”. The importance of the scale is
based on the necessity to collect the ideas of certain groups for the decision making. Therefore,
psychometric scales include the uncertainty that works on the subjectivity of individual answers.
The Likert Scale brings some weakness to this evaluation process by losing information about the
uncertainty of the answers provided. So, an approach of the Likert Scale incorporating the Fuzzy
Sets Theory - considering the uncertainty and/or the ambiguity in the answer of the interviewed -
make the discussion relevant. Towards that, in this paper are shown some literature strategies
that seek to improve the Classic Likert Scale by the Fuzzy Sets Theory. In order to confirm if
the Fuzzy Likert Scales are more satisfying than Classic Likert Scale, tests are fulfilled in the
previous considerations seeing hypothetical and real cases, evaluating metrics such as: mean,
standard deviation and agreement among the answers. So, bringing reliability to the areas that
use the method in order to be more assertive on its analizes and considering best what the group
studied indeed tried to show/inform.
Tipo: TCC2020-01-01T00:00:00ZUma abordagem de programação matemática para o número de envoltória de um grafo
http://repositorio.ufc.br/handle/riufc/42201
Título: Uma abordagem de programação matemática para o número de envoltória de um grafo
Autor(es): Sousa, Gabriel Hellen de
Abstract: The hull number of an undirected graph G = (V;E), where V is the set of vertices and E is
the set of edges, consists of the smallest number of vertices that, initially contaminated, can iteratively contaminate the whole graph. The types of contamination (convexity) studied in this work were geodetic, P3, and P3∗. Determining the hull number is an NP-hard problem, even for bipartite graphs. In this work, mathematical models and heuristics for the problem were studied and implemented. To solve the models, the CPLEX was used, coupled with the C ++ programming. The same language was used to code the heuristic. The graphs used as test instances were bipartite and arbitrary graphs, created from two parameters: the number of vertices and a probability factor to define the existence of edges. The results presented by each model and the heuristic, related to the execution time and solution quality, were stored and compared.
Tipo: TCC2018-01-01T00:00:00ZA inserção de métodos no resolvedor CPLEX: Uma aplicação ao problema de emparelhamento de peso máximo com restrições de conflito
http://repositorio.ufc.br/handle/riufc/42186
Título: A inserção de métodos no resolvedor CPLEX: Uma aplicação ao problema de emparelhamento de peso máximo com restrições de conflito
Autor(es): Vasconcelos, Alysson Monteiro Barbosa
Abstract: Optimization methods seek to find good solutions or, if possible, the best one within a feasible set of possibilities in a reasonable time. In general, they require parameters adjustment and the use of different strategies to find increasingly efficient solutions while taking lesser computational effort. Some solvers, such as CPLEX, are available to handle various optimization problems that fall into the areas of Linear Programming, Integer Programming, Mixed Integer Programming and, to some extent, Quadratic Programming. In addition, they give us the possibility of incorporating our own methods into their tools, in order to further strengthen the solver to tackle the problem in focus. Given this circumstance, our work exemplifies, through the Maximum Weight Matching Problem with Conflict Constraints, how to implement techniques studied during our graduation
course (in order to solve problems of integer linear programming), such as cutting planes,
lagrangian relaxation, branch-and-cut, lagrangian heuristics. We show how to use, customize or incorporate these methods in the CPLEX solver environment, as well as we evaluate the effects on the solver performance due to different ways of use, parameterizations or applied changes
Tipo: TCC2018-01-01T00:00:00Z