The integration of complex systems is an important aspect of systems engineering. This paper defines six integration principles to consider when planning and executing system development and integration processes. This paper describes these integration principles and validates them through a historical system survey. The 14 systems studied represent both integration successes and integration failures to show the universal applicability of the principles. The historical system analysis supported the validity of four of the six principles. The validity of one of the remaining principles could not be concluded through the evidence gathered. The validity of the final principle was inconclusive due to a lack of evidence found. Understanding these principles and how to apply them to an integration program will increase the probability of successful integration of future systems.

Component and subsystem reuse has been an important tool in controlling the cost and schedule requirements of developing new aerospace systems. Although the mere utilization of component reuse cannot be shown to influence system integration success significantly, previous research has shown that interactions between reuse and other integration principles do significantly influence integration success. The research described in this paper leverages historical system data to characterize these interactions and assess the influence of these interactions on integration success. This research identifies four characterizations of interactions between reuse and the other principles that significantly influence system integration success when component reuse is included in the system design.

The integration of complex systems is an important aspect of systems engineering.Previous research derived six integration principles and qualitatively validated four of them using a data set of 14 systems. Of the two non-validated principles, one was determined to be confounded with two of the four validated principles and is hence not considered in this research. This paper describes the quantitative validation of the resulting five integration principles based on an expanded data set of 52 systems. This expanded data set is analyzed statistically, and the interactions between integration principles are also evaluated. This research quantitatively validates four of the five integration principles and identifies three principle interactions that are significantly related to integration success, solidifying validity of the principles, and identifying three cases where the principles interact that must be further explored.

The integration of reuse components and subsystems into complex systems is continuing to increase in development programs as a method to reduce resources needed and to reduce complexity. Previous research identified that reuse can commonly be a driver of system integration failures. A previous work identified four considerations for ensuring that reuse is integrated into a system successfully. This paper adapts a framework from the discipline of Strategic Foresight that provides a fixed roadmap for addressing the considerations. The framework consists of 10 guidelines across six phases, Framing, Scanning, Forecasting, Visioning, Planning, and Acting. The framework was evaluated against 18 historical systems that failed due to reuse components or subsystems to determine if the framework would have mitigated the failure mechanisms around the reuse. The framework was found to have mitigated 100% of the failure mechanisms across the 18 systems.