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beast. The differences are subtle, so as to benefit from a common language base; but essential. realtime Java
sets itself apart by having much stronger threading semantics and a means of avoiding timing anomalies due
garbage collection, ideally while maintaining the reference consistency automatic object deallocation ensures.
In the past, reference consistency was maintained by disallowing or severely limiting dynamic memory management.
This approach works well for state machine like tasks, but not for more complex applications. The
up and coming Safety Critical Java standard (JSR 302) provides some more flexibility than currently tolerated
by providing a stack like approach to memory allocation and deallocation. This will enable the Java language
to be used at the highest criticality levels in the near term, but does not address increasing complexity well.
In the long run and for applications into the medium criticality today, where complexity is already challenging,
realtime garbage collection offers a more practical solution. Garbage collection relieves the application developer
of reference inconsistency concerns, such as dangling pointers and memory leaks, since these can be
guaranteed by the Java runtime environment. A deterministic, realtime garbage collector can also ensure that it
does not interfere with application meeting timing deadlines.
New work on object oriented technology in SG-5 of the SC 205 / WG 71 Plenary to update the DO-178 standards,
will make certification of Java technology, including the use of virtual machine technology and garbage
collection, easier. In the past, these technologies where up to the discretion of individual certification experts,
who often have only minimal understanding of OO Technology. New standards will provide both stronger
guidelines and rationale for how certification should conducted.
This talk outlines the important Java standards, such as the realtime Specification for Java (JSR 1 and JSR 282)
and Safety Critical Java (JSR 302), as well as proposed changes from SG-5 for object oriented technology.
New garbage collection technology will also be covered. This should give the attendee a good background in
the state-of-the-art of realtime Java Technology and safety certification.
Title: Knowledge Based Engineering using CATIA V5 for High Lift Device Design at Airbus
Authors: T. Baudach, Dr S. Kleiner
engineering methods AG
Time: November 3, 2009 5:20 pm
Room: Candela
In the High Lift Device Design domain Knowledge Based Engineering (KBE) for aero, structure, kinematic and
system design has been decided as a core element in lean engineering at Airbus. Hence, knowledge based
engineering and process chains supported by Template Based Design using CATIA V5 as well as the integration
of calculation and simulation in early design stages were introduced. The following article describes the
usage of KBE based on an example for High Lift Device structure design at Airbus, Germany.
During the concept phase of High Lift Devices different design alternatives and variants come up and need to
be validated concerning requirements regarding weight, loads and static issues, manufacturing, costs, etc. 3D
CAD models of devices are designed and analysed using CATIA V5 in order to meet the demands in early
stages. The structure of high lift devices contains multiple but similar elements such as ribs, spars and stringers
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which are used as stiffeners. These stiffeners are represented by concept models based on wireframe elements
in CATIA V5 in early design stages. Based on an overall wireframe model simple solid elements were set up in
order to construct the device and perform digital mock-up (DMU, e.g. clash and assembly analysis) and weight
management analysis based on a 3D solid model.
The integration of knowledge capabilities in CAD systems allows capturing, sharing and re-using of design rationale
and engineering know how. KBE has led to massive progress in efficient CAD design and allows an easy
way to modify features and models, re-use and adapt CAD models for design changes, create product variants
and families. High level templates automatically adapt themselves to new design contexts. This full morphing
concept reduces design time and costs to levels not previously met in the industry. In order to automate the
High Lift Design process and reduce repetitive manual tasks the solutions CADSTRUCTURAS for device design
(CAD Structure Assistant) was implemented based on KBE technologies.
At Airbus design templates for ribs, spars, stringers etc. and KBE tools have been provided for the design of
high lift devices. Functions of CATIA V5 Knowledgeware such as document templates, power copies and user
defined features allow designers and engineers to embed knowledge into the structure design and leverage
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
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