When agents can significantly increase other agents’ utility at a moderate cost, the socially optimal outcome is for all agents to repeatedly provide favors to each other whenever they can. However, when agents cannot support or enforce a market system, this forms a situation similar to the repeated prisoner’s dilemma because each agent can unilaterally improve its own utility by refusing to he...

We argue in favor of the presumed c o m m i t protocol by proposing two new presumed commit variants that sign$cantly reduce the cost of logging activities associated with the original presumed commit protocol. Furthermore, for read-only transactions, we apply our unsolicited updatevote optim’zationand show that the cost associated with this type of transactions is the same in both presumed com...

Historical trends in face perception research during the past half century are summarized. The dual process model offered by cognitive neuroscientists to account for the perception of identity and emotion expression in the face is briefly reviewed together with supporting evidence. An ecological approach that incorporates missing pieces of face perception is offered as an additional, broader co...