How to Analyze Graph-Based Models - Www-st.inf.tu-dresden.de ...
How to Analyze Graph-Based Models - Www-st.inf.tu-dresden.de ...
How to Analyze Graph-Based Models - Www-st.inf.tu-dresden.de ...
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Layering of Sy<strong>st</strong>ems<br />
► To be comprehensible, a sy<strong>st</strong>em should be <strong>st</strong>ruc<strong>tu</strong>red in layers<br />
■ Several relations in a sy<strong>st</strong>em can be used <<strong>st</strong>rong>to</<strong>st</strong>rong> <strong>st</strong>ruc<strong>tu</strong>re it, e.g., the<br />
♦ Call graph: layered call graph<br />
♦ Layered <strong>de</strong>finition-use graph<br />
♦ Layered USES relationship<br />
► A layered architec<strong>tu</strong>re is the dominating<br />
<strong>st</strong>yle for large sy<strong>st</strong>ems<br />
► Outer, upper layers use inner, lower<br />
layers (USES relationship)<br />
► Legacy sy<strong>st</strong>ems can be analyzed for<br />
layering, and if they do not have a<br />
layered architec<strong>tu</strong>re, their <strong>st</strong>ruc<strong>tu</strong>re can<br />
be improved <<strong>st</strong>rong>to</<strong>st</strong>rong>wards this principle<br />
Prof. Uwe Aßmann, Softwaretechnologie II<br />
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