Blue Herd is a project in IBM Research to investigate automated captioning for videoconferences. Today videoconferences are held among meeting participants connected with a variety of devices: personal computers, mobile devices, and multi-participant meeting rooms. Blue Herd is charged with studying automated real-time captioning in that context. This poster explains the system that was developed for personal computers and describes our experiments to include mobile devices and multi-participant meeting rooms.

SOM (IBM's System Object Model) removes a major impediment to reuse in Object-Oriented Programming by facilitating the programming of release-to-release binary compatible class libraries. This is accomplished by supporting a large number of compatibility preserving transformations. Taken together these transformations compose a discipline for programming evolving class libraries.

This paper reports on the evolution of metaclass programming in SOM (the IBM System Object Model). Initially, SOM's use of explicit metaclasses introduced metaclass incompatibilities. This was cured by having SOM dynamically derive an appropriate metaclass by interpreting the “metaclass declaration” as a constraint. In effect, inheritance is given a new dimension, because the constraint is also inherited. The derived metaclass is the least solution to all these constraints. Subsequently, this cure led to the possibility of metaclasses conflicting over the need to assign meaning to a method. The cure for this problem is a framework that facilitates the programming of metaclasses that cooperate on the assignment of meaning to methods.

In SOM, the IBM System Object Model, a class is a run-time object that defines the behavior of its instances by creating an instance method table. Because classes are objects, their behavior is defined by other classes (called metaclasses). For example, a “Before/After Metaclass” can be used to define the implementation of classes that, by suitable construction of their instance method tables, arrange for each invocation of a method to be preceded by execution of a “before method” and followed by execution of an “after method”. This paper introduces and solves the problem of composing different Before/After Metaclasses in the context of SOM. An enabling element in the solution is SOM's concept of derived metaclasses, i.e., at run-time a SOM system derives the appropriate metaclass of a class based on the classes of its parents and an optional metaclass constraint.

A fairness property, called U-fairness, is studied in the context of the design of distributed systems with multiparty interactions. This is done with an overlapping model of concurrency. A distributed algorithm implementing the fairness notion is presented. U-fairness is shown to be more appropriate to the design of distributed systems than other known fairness notions because it provides an abstraction for stable property detection whereas the other fairness notions do not.>