Expanding the trade space: an analysis of requirements tradeoffs affecting system design - Tutorial

Acquisition Review Quarterly, Wntr, 2002 by Mark W. Brantley, Willie J. McFadden, Mark J. Davis

The Department of Defense Simulation-Based Acquisition (SBA) initiative focuses on identifying opportunities to improve materiel procurement by using information technologies to increase military utility, decrease life cycle costs, and decrease the time to develop and field the system. Implementing this initiative requires identifying the necessary analysis tools, constructing a collaborative environment, and developing a method to make timely decisions based on the results of the analysis. This paper focuses on the latter two components. In particular, it analyzes the opportunities to implement the SBA initiative during the development and analysis of the system's requirements trade space. We present a methodology for a holistic approach to determining the system's requirements. This methodology seeks to use models and simulations to support decisions that occur throughout the system's life cycle while in the system's concept development phase and then revisit these decisions as the program matures.

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The Department of Defense Simulation-Based Acquisition (SBA) initiative focuses on improving the acquisition process through the integrated use of models and simulation. Consequently, acquisition issues concerning interoperability, training, education, research and development, production, testing, operation, and support must be factored into the life cycle development of a system from the origin of its need to its retirement from the force. This requires the acquisition community to establish effective procedures and processes that develop systems that are interoperable with other systems and integrated into our force structures and cultures. This will maximize system capabilities and increasing strategic, operational, and tactical force performance. The research methodology presented in this paper provides a means of integrating modeling and simulations throughout a system's acquisition life cycle. This follows to the precepts and principles of SBA in the area of trade space analysis.

THE TRADE SPACE

The "trade space" can be defined as the set of program and system parameters, attributes, and characteristics required to satisfy performance standards. Decision makers define and refine the developing system by making tradeoffs with regard to cost, schedule, risk, and performance; all of which fall within the systems trade space. Traditional trade space methodologies often support "stove-piped" programs that conduct multiple distributed but disparate analyses. These trade space studies compare very specific courses of action against specific criteria. They consider other courses of action only if all of the initial ones are infeasible. Thus, the course of action chosen may not necessarily be the optimal solution or even a more robust solution; it is merely the best solution out of the study set.

However, by using models and simulations (M&S) throughout the system's life cycle, particularly within the requirements generation phase, it is possible to expand the number of feasible alternatives within the trade space analysis. In addition, the systems approach to trade space analysis necessitates the integration of study results. This methodology is consistent with SBA initiatives, which envision removing stovepipes and conducting simultaneous, continuous analysis throughout the life cycle of a program. This is vastly different from the sequential trade studies that relied on developing specific courses of action. M&S used early in the acquisition process impose fewer limitations on finding a set of alternatives within the trade space. The result is a more robust solution space for decision makers. This will allow the exploration of "what if" trade-off scenarios to more effectively and efficiently assess mission performance requirements and provide better stewardship of scarce resources.

The following sections of this paper will further clarify the methodology. First, we present a case study of the traditional trade space analysis methodology and then provide a methodology that will support implementing the SBA initiative.

FAMILY OF MEDIUM TACTICAL VEHICLES (FMTV) CASE STUDY ANALYSIS

The following assessment of the FMTV program is not intended as a critique of the program's analysis. Instead, this section is included to provide examples of the types of studies currently used and to contrast them with the proposed methodology using existing M&S tools from the SBA perspective. The Tactical Wheeled Vehicle Fleet Requirements Study in (Department of the Army, 1980) and the REVAL 80 study (Department of the Army, 1984) were not specifically conducted for the FMTV program. More exactly, the studies were used to establish the continued need for a medium weight cargo vehicle fleet.

Based on projected wartime payload weights and payload dimensions, these studies determined that the optimum cost-effective mix of the tactical wheeled vehicle fleet was in payload categories of 1.25 ton, 2.5 ton, 5 ton, and 10 ton basic cargo trucks. The Cost and Effectiveness Analysis (COEA) studies in 1987 and 1991 justified the FMTV program (Department of the Army, 1987a, 1991a). The COEA study analyzed three courses of action for improving the medium tactical vehicle fleet: