Cobweb, a human-like category learning system, differs from most cognitive science models in incrementally constructing hierarchically organized tree-like structures guided by the category utility measure. Prior studies have shown that Cobweb can capture psychological effects such as basic-level, typicality, and fan effects. However, a broader evaluation of Cobweb as a model of human categorization remains lacking. The current study addresses this gap. It establishes Cobweb's alignment with classical human category learning effects. It also explores Cobweb's flexibility to exhibit both exemplar- and prototype-like learning within a single framework. These findings set the stage for further research on Cobweb as a robust model of human category learning.

Evaluating the anodized tantalum pentoxide (Ta2O5) that has been recently reported as a dielectric for low-voltage electrowetting-on-dielectric (EWOD) devices, we find a severe deterioration in performance if the working liquid is actuated with positive dc voltage. In an effort to reduce the limitation of this otherwise attractive dielectric material for EWOD, proposed herein is a Ta2O5 layer prepared by anodizing a sputtered Ta2O5 film. This sputtered-anodized Ta2O5 allows the use of positive dc signals, while maintaining the low-voltage actuation for which the anodized Ta 2O5 was originally introduced. All the EWOD tests were performed with a conductive liquid droplet in an air environment. © 1992-2012 IEEE.