The gradually varied surface was introduced and studied in digital and discrete spaces by Chen. The basic idea of introducing gradually varied surfaces is to employ a purely discrete interpolation algorithm to fit a discrete surface when the desired surface is not required to be “smooth.” In this paper, we generalize the concept of gradually varied surfaces. A digital surface is defined as a ma...

Some accounts imply that basic-level emotion categories are acquired early and quickly, whereas others imply that they are acquired later and more gradually. Our study examined this question for fear, happiness, sadness, and anger in the context of children’s categorization of emotional facial expressions. Children (N= 168, 2–5 years) first labeled facial expressions of six emotions and were th...

Association mining explores algorithms capable of detecting frequently co-occurring items in transactions. A transaction can be identified with a market basket—a list of items a customer pays for at the checkout desk. In this paper, we explore a framework for the detection of changes in the buying patterns, as affected by fashion, season, or the introduction of a new product. We present several...

We consider auction mechanisms for the allocation ofM items that are identical to each other except for the fact that the items have different expiration times, and each item must be allocated before it expires. This model seems applicable in many economic situations where both items and buyers have a finite “life-time”, e.g. the allocation of transportation tickets. We are interested in situat...