A Technical History of the SEI

were delivered to Army and Air Force programs, along with civil and defense agencies. One program
invited the SEI to evaluate its CBS practices to highlight possible deficiencies. As a result,
the SEI saw the need for a more robust example of a development process. This provided the genesis
to create the Evolutionary Process for Integrating CBS (EPIC) that subsequently was licensed
by IBM Rational and used as the basis for a CBS plug-in for their Rational Method Composer 7.5
process tool [IBM 2010].
Assurance Cases: Addressing Systems of Systems Challenges
By the beginning of the new millennium, another evolution in approaches to implementing software
systems was taking place in defense and federal government communities: net-centric warfare,
interoperability, and the creation of systems of systems (SoS). The SEI created the Integration
of Software-Intensive Systems initiative. This initiative leveraged the rich history with
COTS-based systems, open systems, reengineering, and software architecture principles to tackle
the growing need for reliable and timely interoperation across multiple systems and organizations.
Since 2004, the SEI has worked with an international community of collaborators to create practical
concepts, frameworks, and methods that enable SEI customers to effectively evolve to the
Global Information Grid (GIG) and potentially realize the benefits of net centricity. As serviceorientation
is one approach for net-centric and SoS implementations, the SEI developed extensive
expertise in service-oriented architecture (SOA), creating courses for government personnel, developing
a family of products (including SMART) to support the migration from traditional to
SOA-based systems, and leading the international community in the development of a SOA research
agenda.
Net centricity and systems of systems bring new engineering challenges to government communities
on a scale not previously seen. Systems of systems are not built from scratch with a single organizational
entity in control. Rather, they evolve from (parts or all of) existing systems, in varying
stages of development and fielding, that are engineered, managed, and funded across multiple
organizations, usually with no single governing entity. The SEI has developed methods and techniques
to assist programs to gain insights into critical perspectives and into expectations about
user demands that exceed those typical in product-centered engineering.
A concern for DoD systems was the need to shorten the certification process for safety, system
reliability, or security. Traditional software and systems engineering techniques, including conventional
test and evaluation approaches, were unable to provide the justified confidence needed.
Consequently, a methodology to augment testing and evaluation was required. The SEI’s experience
in areas related to DoD certification needs through its work on rate monotonic analysis and
Simplex led to a more general interest in performance-critical systems. Concurrently, the SEI was
pursuing software issues associated with fault-tolerant computing and systems of systems. Because
of their size, complexity, and continuing evolution, and because net-centric systems can exhibit
undesired and unanticipated emergent behavior, the SEI decided on an approach using assurance
cases.
An assurance case provides a means to structure the reasoning that engineers use implicitly to
gain confidence that systems will work as expected. The SEI’s early work on assurance cases was
funded by NASA and, although NASA has not yet embraced the idea, NASA research continues
on assurance case approaches. As a result of work with the SEI [Weinstock 2009], the U.S. Food
CMU/SEI-2016-SR-027 | SOFTWARE ENGINEERING INSTITUTE | CARNEGIE MELLON UNIVERSITY 201
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