The design structure system: A method for managing the design of complex systems

TLDR

Systems design must coordinate interdependent variables and planning decisions, yet conventional methods such as critical‑path analysis fail to handle the circuit‑like dependencies that arise. The paper introduces techniques that explicitly model these circuit‑like dependencies within system design. By mapping variable interdependencies, estimating usage, and tracking design iterations and information flow, the techniques generate an engineering plan and a critical‑path schedule for change implementation, suitable for both automated and traditional engineering environments.

Abstract

Systems design involves the determination of interdependent variables. Thus the precedence ordering for the tasks of determining these variables involves circuits. Circuits require planning decisions about how to iterate and where to use estimates. Conventional planning techniques, such as critical path, do not deal with these problems. Techniques are shown which acknowledge these circuits in the design of systems. These techniques can be used to develop an effective engineering plan, showing where estimates are to be used, how design iterations and reviews are handled, and how information flows during the design work. This information flow can be used to determine the consequences of a change in any variable on the rest of the variables in the system, and thus which engineers must be informed and which documents must be changed. From this, a critical path schedule can be developed for implementing the change. This method is ideally suited to an automated design office where data, computer input and output, and communications are all handled through the use of computer terminals and data bases. However, these same techniques can also be effectively used in classical engineering environments.