Computational monitoring and steering using network-optimized visualization and Ajax web server

We describe a system for computational monitoring and steering of an on-going computation or visualization on a remote host such as workstation or supercomputer. Unlike the conventional "launch-and-leave" batch computations, this system enables: (i) continuous monitoring of variables of an on-going remote computation using visualization tools, and (ii) interactive specification of chosen computational parameters to steer the computation. The visualization and control streams are supported over wide-area networks using transport protocols based on stochastic approximationmethods to provide stable throughput. Using performance models for transport channels and visualization modules, we develop a visualization pipeline configuration solution that minimizes end-to-end delay over wide-area connections. The user interface utilizes Asynchronous JavaScript and XML (Ajax) technologies to provide an interactive environment that can be accessed by multiple remote users using web browsers. We present experimental results on a geographically distributed deployment to illustrate the effectiveness of the proposed system.