Internal cluster validity measures (such as the Calinski-Harabasz, Dunn, or Davies-Bouldin indices) are frequently used for selecting appropriate number of partitions a dataset should be split into. In this paper we consider what happens if treat such indices objective functions in unsupervised learning activities. Is optimal grouping with regards to, say, Silhouette index really meaningful? It...

1 Teresa L. Larkin, American University, Department of Physics, 4400 Massachusetts Ave. NW, Washington, DC 20016-8058 [email protected] 2 Maria Feldgen, Universidad de Buenos Aires, Facultad de Ingenieria, Caseros 3580 P7, Dept. 220, Buenos Aires, Argentina 1263 [email protected] 3 Osvaldo Clúa, Universidad de Buenos Aires, Facultad de Ingenieria, Caseros 3580 P7, Dept. 220, Buenos Aires, Ar...

Introduction. Treatment of Rockwood Type 3 Acromioclavicular joint dislocation is controversial. We compared the long-term functional outcome of early repair of coracoclavicular ligament and internal fixation (Tension Band Wiring) with delayed reconstruction by modified Weaver-Dunn procedure for Type 3 dislocations. Method. Retrospective analysis of case records and telephone review to assess t...