Parallelizing the Simulation of Shipboard Power Systems

An important contributor to U.S. military superiority is the continued superiority in computing and communications. For the last few decades, military superiority in this area has rested in a large part on Moore’s Law, which is a description of the fact that investment in appropriate semiconductor technology led to better performance, which led to new products that organizations and individuals would buy, which led to further investment in the technology. The Department of Defense has learned to exploit this rapid change in technology even though it does not fit well with its budget or procurement cycles. This ability to manage technological
change has helped achieve superior capability.

But Moore’s Law growth has ended. In a purely technological level, we can still double the density of the components on a processor chip, but it does not lead to sufficient system improvement to warrant the investment. So, the Department of Defense, as well as companies needing a competitive advantage, must find other solutions.

The ESRDC was not alone in recognizing this situation. Within the government broadly, this is an issue being addressed by the Office of Science and Technology Policy, who has staff focused on this finding a good solution for the U.S, government. In Defense, DARPA has staff members that recognize the need to help maintain military superiority while transitioning from an environment driven by Moore’s Law. Outside of DOD, this is one of the top technical
challenges being addressed by the IEEE, the leading global technical organization in the field of electrotechnology.

The ESRDC was early in recognizing the issue because the development of future ships that are efficient, effective, and employ emerging technology requires exhaustive simulation before and after their construction. Today, however, it is not possible to conduct the required simulations of large shipboard models due to the length of time required to complete the solution when using commercial software and desktop computers.

This led to the ESRDC exploring three options:
 Use of special purpose computers:
The ESRDC does have access to special purpose computer systems to address appropriate near term problems. And this has been successful. The need for hardware procurement and training costs coupled with the historical concerns over the longevity of special purpose computing have suggested this will be a valuable
research tool, but it will not be widely adopted within the Navy and the shipbuilding industry.

 Use of Field-Programmable Gate Arrays (FPGA’s):
FPGA’s can be considered quasi-special-purpose computers that provide excellent computational speed by limiting functionality. They have found use, for example, in control systems. The ESRDC explored with ONR the possibility of exploiting this technology for ship simulation. The challenge, however, was that ONR was already
exploring this technology in general, but the anticipated progress was expected to be too slow to support ship design. Furthermore, some of the issues cited for special purpose computers would likely prevail with the FPGA alternative.

 Use of technologies that are in the mainstream of computer evolution:
The computer industry has been evolving to more parallel systems to compensate for lack of speed on a given processor. Multicore systems provide promise for continued improvement and are commercially available for decreasing cost. The primary challenge is that legacy software typically must be rewritten to operate with best
efficiency on such systems. For adaption to ship power system design, the major challenge was automated model partitioning and parallelization into subsystems of less computational burden to facilitate the use of legacy systems. The ESRDC has made a significant contribution to solving this problem.

The ESRDC solution has been developed over time to match the needs of the Navy and the shipbuilding community while also being sensitive to the relevant commercial development. Discussion with ship yard leaders led to a strong endorsement to have a solution as close to Simulink [4-6] as possible. This is an understandable constraint as most engineers today graduate being competent in such program. A different approach would increase training costs
and thus overall costs. The ESRDC approach meets this need by Simulink as the user interface.

To make the capability available to as wide an audience as possible, the initial development will be made available to all users under Navy-sponsored programs. To move the capability from the
ESRDC to the Navy, the ESRDC will make the software available on the web to students at the Naval Postgraduate School to help support their research. This is a research environment
involving naval officers and the system is helping them improve the quality of their education during their limited time at NPS. The arrangement is that the program is provided on the web
through a private link between NPS and the University of Texas at Austin. The developer in Austin can monitor performance and quickly help students resolve any problems. Discussions
are underway to next open the link to research projects at the U.S. Naval Academy after the system is sufficiently robust to be used by less experienced users.

The next step would be to transfer the capability to NAVSEA and to the shipyards. Those implementations must be even more robust, however, as much of the information they process is classified. That is, moving from research to production, the penalty for failure is higher.

A widely accessible accelerated simulation approach provides key Navy users with early capability to use emerging software approaches to modeling. The open structure permits the
focus to be on a structure that works for the application. In addition, collaboration with software vendors permits the information developed in this project to help inform the commercial
development.