Domain Independence

Most schedulers solve a limited class of scheduling problems in a single domain. In contrast, the Vishnu problem representation framework allows the user to specify the problem to solve and adapts to any domain. For example, Vishnu can schedule taxicab pickups just as easily as soccer fields, or classrooms, or service visits. The flexibility to tailor Vishnu to the user's unique requirements is what makes it so powerful.

Optimization

An automated scheduler uses genetic search to define optimized schedules. Most scheduling problems encompass both hard constraints (those that absolutely must be satisfied) and soft constraints (those that can be violated but at a cost). As scheduling problems become more difficult, the number of tradeoffs that must be made increases proportionately. Optimized scheduling evaluates the costs of all of the possible tradeoffs to identify the optimal solution.

Web Server Mode

In this mode, all interactions with the system are through a standard Web server. Users can employ a standard Web browser to define scheduling problems, view the schedules, and control when the automated scheduler runs. The dynamically created Web pages feature:

• Color-coded Gantt charts
• Full views into all the data
• Editing of data and schedules
• Full hyperlinking and easy navigation
• External data feeds (e.g. from a corporate database)use a well-defined XML interface.

Integration

Input, output, and problem specification for the Vishnu Reconfigurable Scheduler are specified by XML schema.

Collaboration

Multiple Vishnu schedulers can collaborate either as standalone java processes or within a Cougaar agent framework.

Rapid Prototyping

The standalone Vishnu Scheduler GUI shows and allows editing of schedules, data, scheduling rules, and custom data views. It comes bundled with an internal scheduler to allow rapid prototyping while scheduling rules are being developed.