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Joint Meeting of the Wednesday, January 9, 2002 Avionics Architecture Presented by Edward Colbert, The Society of Automotive Engineers (SAE) is developing a standard Avionics Architecture Description Language (AADL) based on the Unified Modeling Language (UML) and MetaH, an architectural design language with a supporting toolset for specifying, analyzing, and integrating computer control systems. MetaH was designed by Honeywell for the specification of real-time, fault-tolerant, securely partitioned, dynamically reconfigurable multi-processor system architectures. UML is the Object Management Group's standard language for object-oriented software development. We will look at the integration of MetaH and UML. Since MetaH was designed to meet the requirements of aircraft and missile
avionics and flight control, it can be valuable in other embedded, time-critical
applications where a highly integrated, rapidly evolvable approach is needed,
such as robotics. Developers use MetaH to specify (1) the code modules that form
the application, (2) the execution behavior of the application, (3) the target
hardware and software environment, and (4) the allocation of the application to
hardware. The specification is then analyzed to determine whether the system is
schedulable, reliable, and safe. The MetaH tools can generate the integrated
code for the application components, an executive, and "architectural glue", all
customized for the target hardware environment. In this presentation, we will review an integration of UML and MetaH that will be proposed to SAE as the standard. Ed Colbert is the director of the USC Software Engineering Certificate Program and a Lecturer in the USC Computer Science Department. He is a contributor to the Model-Based Software Engineering (MBASE) method of the USC Center for Software Engineering. Ed has been teaching object-oriented methods, software engineering, and the Ada, C++, and Java programming languages since 1982, and since 1986 consulting as well. He is consulting on the definition of the Architecture Design Language (ADL) for real-time, safety-critical systems based on the Unified Modeling Language ("UML"), and Honeywell's MetaH; the ADL will be proposed as the standard of Society of Automotive Engineers (SAE). He created the Colbert Object-Oriented Software Development method ("OOSD"), which supports analysis and design for implementation in languages such as Ada, C++, and SmallTalk. NASA Langley Research Center used OOSD for a Software Engineering Process manual, choosing OOSD partly for its strength in real-time software development. Clients of Ed's company Absolute Software include Aonix, Computer Science Corporation, TRW, Lockheed Martin, e-SIM, KPMG Peat Marwick, and Honeywell. Ed has delivered presentations at the International Conference on Reliable Software Technologies (Belgium, 2001), TOOLS (California, 2000), Ada Europe (England, 1997), TRI-Ada (1996, '95), UNICOM (England, 1993), OOPSLA (D.C., 1993), ObjectExpo (New York, 1993), ObjectExpo Europe (England, 1992), TRI-Ada (Florida, 1992), LOOK (Denmark, 1992), OOP (Germany, 1992), and SCOOP Europe (England, 1991). He is a graduate of the University of Michigan (M.S. Computer & Communication Sciences, 1981; B.S. (honors) Chemistry and Biology, 1979). Director, Software Engineering Certificate Program, USC, (213)
821-1240, ecolbert@usc.edu |
LA ACM Chapter December Meeting. Held Wednesday January 9, 2002. The presentation was "Avionics Architecture Description Language and the Unified Modeling Language (UML)" by Edward Colbert of USC and Absolute Software Co. This was a joint meeting of the Los Angeles Chapter of ACM, IEEE Computer Society and LA SIGAda. Ed said his presentation was developed by him and by Bruce Lewis of the U.S. Army Aviation and Missile Command (AMCOM). The background of the languages he will speak on was from the Society of Automotive Engineers (SAE) which developed the standard Avionics Architecture Description Language (AADL). Basic research has been done under sponsorship of the U.S. Defense Advance Research Agency (DARPA) and a joint task force of the Office of the Secretary of Defense (OS-JTF). It is based on META-H that was designed by Honeywell for specification of real-time, fault-tolerant, securely partitioned, dynamically reconfigurable multi-processor system architectures and on the Unified Modeling Language (UML) the Object Management Group's (OMG) standard language for object-oriented software development. The purpose was to develop a method to try to reduce the problems of developing embedded real-time systems. With these systems there is difficulty in upgrading capabilities and ensuring reliability, safety and in obtaining good performance. There are integration problems during development and there are few means of assessing the impact of decisions early. Adding or changing resources is expensive, if it is possible at all. Many products have to reduce their capabilities in order to produce an usable system. Typically embedded systems have long life spans and with the continued advancement in hardware capabilities soon become obsolete and must be upgraded. The current development process is manual, paper intensive, error prone and resistant to change. A well-designed architecture is necessary to have a smooth development program but in practice this rarely happens. What is AADL? It is used to describe high level designs. It treats the system as a collection of connected components. The layout of the components defines the structure and the connectors define communication. AADL does not define algorithms, data structures or circuits. AADL provides notation that supports a particular domain. It provides models and methods to be used by analysts and uses a library specific to the domain. It provides a new engineering paradigm that has a formal specification, provides for early problem detection and repeated system analysis. It makes error elimination easier and provides automatic code generation and integration of the system. It is a model-based system where integration occurs early in the process. Model development starts with creation of the model and analysis of its capabilities. The model is used to generate the system. The effect of changes in the system is understandable from analysis of the model. AADL is based on MetaH, which is ADL with a tool set for specifying, analyzing, and integrating computer control systems. It specifies code modules, behavior and the target hardware and software environment. MetaH began in 1991 with the DARPA Domain-Specific Software Architectures (DSSA) program. The first partitioned target was operational in 1992 and the first multiprocessor target in 1994. By 1998 there were Ada 95 and POSIX executive configurations available. From the beginning in 1991 to the present there have been numerous evaluations and demonstrations on aircraft and missile projects. The results have been very good, with an effort saving of 50% on the overall project and 90% when software is ported from one computing environment to another. MetaH provides for early optimization, portability, reduced cost and ease of validation and verification. The ability to rapidly target from one computing environment to another allows a "software first" approach. Adding UML provides modeling concepts and notations for typical software projects and allows additions and concepts to be added to meet specific needs. Predefined sets can be provided. These don't add anything new to UML but implement specialization for particular environments or domains. The current version of UML is 1.4. The model uses what are called "stereotypes" which are basic units used to build model elements. Tools are provided that manipulate these elements. There are property lists and tagged values that may be attached to elements. Conditions and restraints are added using Boolean expressions. There are three forms: Invariant, pre-condition, and post-condition. Invariant conditions apply during any steady state operation. Ed went on to discuss models, software and hardware interfaces, and implementations in detail. The AADL is a "work in process". The requirements document has been approved and current draft of the AADL standard is about 1/3 complete. The goal is to have the Version 1 standard out by the end of 2003. AADL is expected to have wide application and build upon the success of its predecessor. Some areas of application are vehicle controls, aircraft and missile avionics, and command and control systems. For more information go to Ed Colbert's website at: www.abssw.com or contact him by email at: colbert@abssw.com This was the fifth meeting of the LA Chapter year. Mike Walsh, LA ACM Secretary |
The Los Angeles Chapter normally meets the first Wednesday
of each month at the Ramada
Hotel, 6333 Bristol Parkway, Culver City. The program begins at 8 PM.
From the San Diego Freeway (405) take the Sepulveda/Centinela exit southbound
or the Slauson/Sepulveda exit northbound.
6:30 p.m. Cocktails/Social
The menu choices are listed in the table above.
Avoid a $3 surcharge!!
Make your reservations early.8:00 p.m. Presentation
To make a reservation, call or e-mail John Radbill, (818) 353-8077, and indicate your choice of entree, by Sunday before the dinner meeting.
There is no charge or reservation required to attend the presentation at 8:00 p.m.. Parking is FREE!
For membership information, contact Mike Walsh, (818)785-5056 or follow this link.
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