Dynamics on and of Networks

Keynote Abstracts

Jean-Louis Giavitto, IRCAM, France

Man-Machine Synchronization

Ensemble music is the result of a choreography of events and
expectations in time. And the capacity for real-time synchronization and
coordination is a common ability among trained musicians performing
together a music score. But is a computer able to understand the dynamic
of playing together?

Parts of the answer are provided by Antescofo, a system that attempts to
enable computer-human musical interactions in the context of mixed
music, i.e. when humans and computers are performing together. Antescofo
provides an abstract programmer's model for an artificial musician in an
ensemble with musical real-time constraints. Antescofo ability to
interact musically relies on a dedicated heterogenous model of time,
that encompasses event-driven and time-driven specifications, absolute
and relative time, and subjective and social time. This model of time
makes possible the common understanding of the coordination required to
take part in musical interactions, a first step in the development of a
musical companionship and a practical experience in the possible sharing
of time between man and computers.


 James Marshall, Sheffield, UK. 

‘Optimal’ decisions on graphs:
Optimality theory for decision-making exists at two levels, optimal decisions by individuals, and optimal decisions by groups. Although these levels can be closely related, they are not often studied in conjunction. In this talk I will explain how, on complete graphs, optimal individual decisions can be optimally combined by quorum detection. I will then consider what may happen when we move to incomplete graphs, and how naive-Bayes agents can synchronously integrate social information very simply; in doing so, however, non-optimal information cascades occur within the group. The problem is resolved by moving to the more realistic case of asynchronous decisions, in which social information must be appropriately integrated with private evidence accumulation.