No abstract

Understanding how and why changes propagate during engineering design is critical because most products and systems emerge from predecessors and not through clean sheet design. This paper examines a large data set from industry including 41,500 change requests that were generated during the design of a complex sensor system spanning a period of 8 years. In particular, the networks of connected parent, child, and sibling changes are resolved over time and mapped to 46 subsystem areas of the sensor system. These change networks are then decomposed into one-, two-, and three-node motifs as the fundamental building blocks of change activity. A statistical analysis suggests that only about half (48.2%) of all proposed changes were actually implemented and that some motifs occur much more frequently than others. Furthermore, a set of indices is developed to help classify areas of the system as acceptors or reflectors of change and a normalized change propagation index shows the relative strength of each area on the absorber-multiplier spectrum between −1 and +1. Multipliers are good candidates for more focused change management. Another interesting finding is the quantitative confirmation of the “ripple” change pattern previously proposed. Unlike the earlier prediction, however, it was found that the peak of cyclical change activity occurred late in the program driven by rework discovered during systems integration and functional testing.

No abstract

No abstract

This paper explores recent developments in agile systems engineering. We draw a distinction between agility in the systems engineering process versus agility in the resulting system itself. In the first case the emphasis is on carefully exploring the space of design alternatives and to delay the freeze point as long as possible as new information becomes available during product development. In the second case we are interested in systems that can respond to changed requirements after initial fielding of the system. We provide a list of known and emerging methods in both domains and explore a number of illustrative examples such as the case of the Iridium satellite constellation or recent developments in the automobile industry.

No abstract

Many companies constantly struggle to find cost-effective solutions to satisfy the diverse demands of their customers. In this paper, we report on two recent industry-focused conferences that emphasized platform design, development, and deployment as a means to increase variety, shorten lead-times, and reduce development and production costs. The first conference, Platform Management for Continued Growth, was held November–December 2004 in Atlanta, Georgia, and the second, 2005 Innovations in Product Development Conference — Product Families and Platforms: From Strategic Innovation to Implementation, was held in November 2005 in Cambridge, Massachusetts. The two conferences featured presentations from academia and more than 20 companies who shared their successes and frustrations with platform design and deployment, platform-based product development, and product family planning. Our intent is to provide a summary of the common themes that we observed in these two conferences. Based on this discussion, we extrapolate upon industry’s needs in platform design, development, and deployment to stimulate and catalyze future work in this important area of research.

This article presents definitions for market segments and market applications, product portfolios, and product and process platforms. It also provides methods for planning product architecture and product platforms within that architecture.