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channels. Let S i denote a state (in the pattern instant T r k) where a work piece beingjust processed by some operation Op l according to a recipe j is waiting forprocessing by Op i . The interoperation states S i are used for modeling transportdelays between different locations where processing takes place.(a)(b)Figure 3.4 Model patterns: (a) a fragment of technological process “recipe”;(b) a fragment of a machining unit performing an operationThe root model M 0 can be simplified considerably by abstraction if generalresource and performance estimation problems must be solved (analysis of phaseP2). If the global performance or resource usage are of interest it is possible toabstract from recipe automata and introduce instead the so-called buffer (or storage)variables to T m models – a pair for each (observable in the model) machiningoperation. Since machining operations share their input and output buffers thevariables modeling buffers are joint for several operations. Thus, the machiningview can be constructed from initial T m patterns using the following rule: if tworecipe automata T r 1 and T r 2 include the same operation Op i , then there are buffervariables R i and R i+1 in the modified T m model such that for all operations precedingimmediately Op i in T m their common output buffer is modeled by the variable R i ,and for all operations of T r 1 and T r 2 following immediately Op i their input buffer ismodeled by variable R i+1 . Denoting the number of work-pieces needed for Op i by I iand the number of products or resources released after completing the operation byO i , the guards and assignments of transitions to and from the state Op i in T m* ( i.e.,t(.,i) and t(i,.)), are defined in the following way: G(t xi ) ≡ R i ≥ I i , Asg(t xi ) ≡ R i – I i ;G(t ix ) ≡ RR ≥ R i+1 + O i , Asg(t ix ) ≡ R i+1 + O i (see Fig. 3.4). The machining viewcompletely preserves the parallelism of machining units and can be used forplanning machine load and throughput.UppAal toolbox is one candidate for performing the model checking task(Rennik, 2005). However, it uses XML files which are not comparable withcorresponding database formats. Therefore in practice the XML output fromdatabase is transformed using Python software based model converter Finke,analysed by UppAal, and thereafter tranferred back by expert system Prolog. Thesuitable Java interface application has been elaborated at TUT (Mäe, 2006).In FMS situated at a laboratory of TUT (Fig. 3.5), several technological devicesare involved, including a Milling CNC machine (M8), Robot «Mentor» (M2),Robot «Serpent» (M7), Load module (M4), Height measurement device (M3),Diameter measurement device (M5), Conveyer 1 (M1), Conveyer 2 (M6), Indexedtable (M9), Operator.In Fig. 3.6 a scheme of FMS is presented, a data model (IDEF0) shown in Fig.3.7 (Karaulova, 2002, 2004) can be received after decomposition stages.38