Modeling concepts for VLSI CAD objects
ACM Transactions on Database Systems (TODS)
RCS—a system for version control
Software—Practice & Experience
An editor for revision control
ACM Transactions on Programming Languages and Systems (TOPLAS)
Version Support for Engineering Database Systems
IEEE Transactions on Software Engineering
The art of computer programming, volume 1 (3rd ed.): fundamental algorithms
The art of computer programming, volume 1 (3rd ed.): fundamental algorithms
Minimizing time-space cost for database version control
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Differential files: their application to the maintenance of large databases
ACM Transactions on Database Systems (TODS)
A technique for isolating differences between files
Communications of the ACM
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
A database approach for managing VLSI design data
DAC '82 Proceedings of the 19th Design Automation Conference
Ancestor Controlled Submodule Inclusion in Design Databases
IEEE Transactions on Knowledge and Data Engineering
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A simple model, called a VDAG, is proposed for representing hierarchically specified design data in CAD database systems where there are to be alternate expansions of hierarchically specified modules. The model uses an ancestor-based expansion scheme to control which instances of submodules are to be placed within each instance of a given module. The approach is aimed at reducing storage space in engineering design database systems, and providing a means for designers to specify alternate expansions of a module.The expressive power of the VDAG model is investigated, and the set of design forests which are VDAG-generable is characterized. The problem of determining whether a given design forest is VDAG-generable is shown to be NP-complete, even when the height of the forest is bounded. However, it is shown that determining whether a given forest is VDAG-generable and producing such a VDAG if it exists, can be partitioned into a number of simpler subproblems, each of which may not be too computationally difficult in practice. Furthermore, for forests in a special natural class that has broad applicability, a polynomial time algorithm is provided that determines whether a given forest is VDAG-generable, and produces such a VDAG if it exists. However, we show that it is NP-hard to produce a minimum-sized such VDAG for forests in this special class, even when the height of the forest is bounded.