6 research outputs found
Interplay of Casting and CFD Software for Improved Accuracy of the Simulation
Get PDFThe advantages of using two simulation codes in casting simulations have been investigated: a fnite element code designed to simulate casting pro-cesses, and a fnite volume CFD code designed to simulate thermal and uid-dynamic boundary conditions. The temperature-time curve at an important injection point of a mould system has been measured: in this point, the agreement between numerical and experimental results is very sensitive to the specific boundary conditions that are assumed in the casting simulation. It has been demonstrate that the agreement is good if instead the choice of boundary condition parameters are chosen and tuned to experimental data with the help of a CFD code
Incremental Determinization of Expanding Automata
No full textSubset Construction (SC) is the classical algorithm for the determinization of a nondeterministic finite automaton (NFA) into an equivalent deterministic one (DFA). Although SC works fine in most application domains, it may be inappropriate when the NFA expands over time and determinization is required after each expansion, such as in diagnosis of active systems in artificial intelligence, or in model-based testing in software engineering. For such an expanding automaton, the IDEA algorithm (Incremental Determinization of Expanding Automata) may be more suitable. Given an NFA N, an equivalent DFA D, and an expansion DN of N, the determinization of N' = N + DN into D' is performed based not only on N' but also on DN and D. Rather than starting from scratch the generation of the DFA D' equivalent to N', IDEA applies the set of actions which are sufficient for transforming D into D'. This way, a possibly large part of the determinization process is avoided. Experiments show that the degree of convenience in determinizing expanding automata using IDEA rather than SC largely depends on the nature of the expanding automaton in the actual application domain
