2005
A Model-Based Requirements Database Tool for Complex Embedded Systems
ABSTRACT - It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no
longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software
engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically
encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified
by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the
translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system
behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems
engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering methodology
called State Analysis which provides a process for capturing system and software requirements in the form of explicit models.
This paper describes (1) how requirements for complex aerospace systems can be developed using State Analysis, (2) how these
requirements inform the design of the system software, and (3) how this process has been aided through a State Analysis Database
(SDB) and supporting multi-platform client. The SDB provides a productive, collaborative development environment for State Analysis
that is shared by both systems and software engineers.
International Council on Systems Engineering (INCOSE) International Symposium.
Washington DC.
May
State-Based Models for Planning and Execution
ABSTRACT - Many traditional planners are build on top of existing execution engines that were not necessarily intended to be
operated by a planner. The Mission Data System has been designed from the onset to have both an execution and planning engine
and provides a framework for defining state-based models that can be used to coordinate planning and execution. The models provide a basis
for ensuring the consistency of assumptions made by the execution engine and planner, and a basis for run-time communications
between the planner and execution engines.
International Conference on Automated Planning and Scheduling (ICAPS).
Monterey, CA.
June
A Unifying Framework for Systems Modeling, Control Systems Design, and System Operation
ABSTRACT - Current engineering practice in the analysis and design of large-scale multi-disciplinary control systems is typified by some form
of decomposition -- whether functional or physical or discipline-based -- that enables multiple teams to work in parallel and in relative
isolation. Too often, the resulting system after integration is an awkward marriage of different control and data mechanisms with
poor end-to-end accountability. System of systems engineering, which faces this problem on a large scale, cries out for a unifying
framework to guide analysis, design, and operation. This paper describes such a framework for semi-autonomous control systems that
guides analysis and modeling, shapes control system software design, and directly specifies operational intent. This paper
illustrates the key concepts in the context of a large-scale, concurrent, globally-distributed system of systems: NASA's proposed
array-based Deep Space Network.
IEEE System, Man, and Cybernetics Conference.
Kona, HI.
October
Achieving Control and Interoperability Through Unified Model-Based Engineering and Software Engineering
ABSTRACT - This paper describes the control challenge faced by future exploration systems and outlines a realistic approach to solving it, based upon a unified, principled architectural approach to both software and systems engineering. It concludes by suggesting the steps necessary to put this capability in place for exploration systems.
AIAA Infotech@Aerospace Conference.
Arlington, VA.
September
Data Management in the Mission Data System
ABSTRACT - As spacecraft systems evolve from simple embedded devices to become more sophisticated computing platforms with complex behaviors it is increasingly necessary to model and manage the flow of data, and to provide uniform models for managing data that promote adaptability, yet pay heed to the physical limitations of the embedded and space environments. The Mission Data System (MDS) defines a software architecture in which both control theory and end-to-end data management provide the primary guiding principles. This paper describes how the MDS architecture facilitates data accountability and storage resource management.
IEEE System, Man, and Cybernetics Conference.
Kona, HI.
October
Engineering Complex Embedded Systems with State Analysis and the Mission Data System
ABSTRACT - It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no
longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software
engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically
encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified
by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the
translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system
behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems
engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering methodology
called State Analysis which provides a process for capturing system and software requirements in the form of explicit models.
This paper describes how requirements for complex aerospace systems can be developed using State Analysis and how these
requirements inform the design of the system software, using representative spacecraft examples.
AIAA Intelligent Systems Technical Conference.
Chicago, IL.
September
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