System Architecture

Raphael. The School of Athens. 1509-1510

In this body of work, we examine changes to the fundamental assumptions underlying systems engineering research in practice. We describe how, in recent decades, technical systems – such as computer systems and the Internet – and human organizations have become increasingly large and complex. Most large-scale systems need to undergo changes during their lifetime because the system’s environment will change. Systems that cannot change will have relatively short useful lifetimes. There is a particularly strong link between a system’s flexibility – its capacity to respond to changes – and its architecture, or internal structure. Often, adding flexibility entails adding complexity. Furthermore, flexibility often comes at the cost of some measure of control over the system’s behavior. My key goal is to understand how various types of system architectures help one to design, modify and operate complex systems in a flexible manner. We proposed the first mathematical theory containing explicit metrics for system flexibility, descriptive complexity, and rework potential. These are used to evaluate several “generic” system architectures, with the aim of determining which ones excel under which environmental conditions. We find that no architecture is ideal under all circumstances; rather, a designer may select an architecture that matches the environment in which the system is expected to operate. This implies that systems facing uncertain environments may wish to incorporate a diversity of architectural elements to maintain flexibility while controlling complexity. In paper J21, I show that two different types of flexibility may be defined and combined synergistically to ensure that a system is robust to different types of disruptions. Standard approaches emphasizing modularity are shown to be relatively fragile because they impose a one-to-one mapping between form and function. This also makes them comparatively inexpensive. In contrast, approaches based on abstraction are more robust, albeit perhaps costlier. Finally, despite a proliferation of theories of systems engineering, very few have been tested empirically. We proposed a series of techniques that may be used to assess and evaluate the validity of these theories against empirical measurements, especially in the era of “big data”.

Research on this project is supported in part by the Toyota Mobility Foundation (TMF). The content is solely the responsibility of the authors and does not necessarily represent the official views of the TMF.

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David A. Broniatowski
Associate Professor of Engineering Management and Systems Engineering

My research interests include social media data analytics, engineering system architecture, decision under risk, and online misinformation.

Posts

Our research was selected by INCOSE to be among the best from those published in Systems Engineering in 2018.

Zhenglin Wei presented a paper at CSER.

Publications

Scholars have posited that systems’ architectures drive their lifecycle properties. Often, these architectures are modeled using …

The Engineering Systems (ES) movement set a research agenda that transformed the field of systems engineering. By focusing on complex …

This white paper argues that response options for aggression in space should be informed by the theory of systems architecture, and …

Technical committees for industry consensus standards involve multiple stakeholders. These stakeholders are experts who assess and …

Many engineered systems are biologically inspired. In this paper, we examine the structure of the human nervous system with an eye …

Flexibility is a major concern in engineering design. This paper examines two complementary approaches to designing flexibility into …

A system’s architecture defines its flexibility—the ease with which changes to the system’s structure may be made. Systems …

Scholars have posited that the architecture of a system drives its lifecycle properties. For example, Moses [1] represents “generic …

Scholars have posited that the architecture of a system drives its lifecycle properties. For example, Moses [1] represents “generic …

Eberhardt Rechtin identified four approaches to system design that have come to define the field of systems architecture. Concurrently, …

System structure is a key determinant of system behavior. There is a particularly strong link between a system’s structure and its …

In this paper, I conceive of the flow from capabilities, to requirements, to implementations as an abstraction hierarchy. I show that …

The behavior of a complex system in a changing environment is strongly affected by the system’s architecture. We present an …

The presence of space situational awareness is one approach to mitigating the long-term risks associated with space debris in low Earth …

This paper summarizes the findings of a comprehensive study commissioned by NASA’s space architect and conducted by graduate students …

Talks

Dr. Broniatowski spoke to PhD students about his PhD journey.