THE INFLUENCE OF ARCHITECTURE IN ENGINEERING SYSTEMS

The field of Engineering Systems is distinguished from traditional engineering design in part by the issues it brings to the top. Engineering Systems focuses on abstractions like architecture and complexity, and defines system boundaries very broadly. It also seeks to apply these concepts to the process of creating systems. This paper summarizes the role and influence of architecture in complex engineering systems. Using the research literature and examples, this paper defines architecture, argues for its importance as a determinant of system behavior, and reviews its ability to help us understand and manage the design, operation, and behaviors of complex engineering systems. A. INTRODUCTION Typical engineering design education focuses on specific aspects of design, such as the technical behavior of a set of elements interconnected in a certain way. By contrast, Engineering Systems focuses on a number of abstract concepts first because they provide a general framework for guiding the development of many diverse kinds of systems, so that these systems will provide the desired functions in the desired ways. Among these abstract concepts is that of system architecture. In this paper, we explore this concept and provide a number of ways of appreciating system architecture’s importance in both the practical aspects of system design and in the intellectual aspects of understanding complex systems from a variety of viewpoints. The paper begins with a definition of architecture and its influence on functional behavior, extra desired properties like flexibility and reliability (collectively called “ilities”), complexity, and emergent behaviors. Architectures are not static but instead evolve over long periods as technologies mature. They also evolve during the normal course of designing an individual system. These evolutionary patterns are useful in understanding architecture’s importance. The paper next provides several examples of architectures and illustrates how architecture affects the way systems are designed, built, and operated. The examples include aircraft, automobiles, infrastructures, and living organisms. The importance of architecture is framed in three domains of importance: as a way to understand complex systems, to design them, to manage them, and to provide long-term rationality by means of standards. The abstract concepts of modularity and integrality are shown to be useful for categorizing systems and illustrating how architectural form can influence important system characteristics. Several contrasts are noted between relatively small, deliberately designed products and evolutionary, less-managed large infrastructures. Architecture’s ability to influence the functions and allied properties of systems is shown to extend to robustness, adaptability, flexibility, safety, and scalability. Examples from recent research are given to show how some of these properties might be measured using network models of particular architectures.