eñores, dijo don Quijote, vámonos poco a poco, pues ya en los nidos de antaño no hay pájaros hogaño: yo fui loco, y ya soy cuerdo; fui don Quijote de la Mancha, y soy agora, como he dicho, Alonso Quijano el Bueno. Pueda con vuestras mercedes mi arrepentimiento y mi verdad volverme a la estimación que de mí se tenía” (II, 74; 1220). With these apparently straightforward words, Alonso Quijano adm...

Interaction between humans and machines is being increasingly recognized as a crucially interesting "dialogue" that requires modeling, design and evaluation in order to build software systems usable in any form (Web applications, groupware, mobile and ubiquitous systems, etc.). Lots of resources and efforts are being devoted to this task, being the focus of the research community in Human-Compu...