**Author details**

100 Multivariate Analysis in Management, Engineering and the Sciences

additional new instruments.

the technicians.

ranking of each cluster.

that all rods from this cluster should be automated.

The methodology showed was applied to the instruments called extensometers, locates in different points of block F of the dam, a total of 30 extensometers that with one, two or three point rods totalized 72 measures of monthly displacement. This measures were stored over a period of 10 years, totalizing 120 readings (January/1995 to December/2004). It is important to remember that 24 measures out of the 72 were automated by the company. The ranking of the instruments would be a way to choose the instruments without any previous knowledge about its location, features, or other characteristics. In this way, it is possible to think in applying this methodology in further decision-making when it relates to the automation of

The methodology used to analyze the problem of the research was composed by the following form: Ward's method was applied in order to cluster 72 rods of extensometers; at the same time, the Factor Analysis was applied in order to rank the rods; latter, the Factor

In the Factor Analysis applied to the 72 rods, there was not need of investigation for any of the rods, once the communality was high for each of them. Observing the 25 rods of extensometers with the highest communality, 14 rods were identified among the ones that were automated by the team of engineers of Itaipu (the automated rods are the ones considered the most important), in other words, the proposed hierachization method

The Clustering Analysis shows that it is possible to find technical justification for the formation of three clusters. The instruments were clustered according the relevant geological characteristics of the foundation mass, although they were not explicitly shown to

By observing the clusters 1, 2, and 3, the factor analysis was applied within each cluster in order to perform the ranking of the rods of the extensometers. It was possible to notice that the rods of the automated extensometers are, most of the time, among the first ones of the

In order to identify the 24 rods that are the most relevant, we decided to identify the 8 best ranked rods from each cluster. In this case, there would be 15 of the 24 automated rods. This number of rods coinciding with the automated ones in Itaipu would increase with the aid of a specialist for a better interpretation of the results. For instance, this specialist would detect that cluster 1is formed by rods that are extremely important for the monitoring of dams and

Approaches that are similar to this can be used in many other cases, since there are thousands of large construction works of Civil Engineering that use the system of

The approach of an important problem of engineer, the analysis of the instrumentation data of large construction works, clustering techniques and other techniques were applied, in the context of the Multivariate Statistical Analysis, aiming the identification of the instruments

instrumentation, of which the data can and must receive an appropriate treatment.

that are the most significant ones to the analysis of the behavior of dams.

Analysis was applied within each cluster formed by Clustering Analysis.

(without previous clustering of the rods) identified 14 of the 24 automated rods.

Rosangela Villwock \* *Mathematics division, Western Paraná State University, Cascavel, Brasil* 

Maria Teresinha Arns Steiner, Andrea Sell Dyminski and Anselmo Chaves Neto *PPGMNE, Federal University of Paraná, Curitiba, Brasil* 
