y an XOR-join or a place x is an AND-split and y an AND-join or x is an XOR-split or a place, and •
Whenever the max-o w / min-cut algorithm is reporting a maximum | · n2| > 1. only nodes with at least two elements in their preset can serve as a join, we only nodes with at least two elements in their postset can serve as a split and The Ford and Fulkerson algorithm can be used to verify that there are indeed at least two elementary paths leading from a given node x to another node y. This handles. However, to detect all matching operator nodes of a given worko w net, stress the semantical relation between them. Figure 1 shows a simple example can be done in analogy to the approach described in [5] to detect PT and TP node. Once all matching operator pairs of a given worko w net are detected, where stands for the nodes of type AND-split/join respectively and As/j Xs/j all pairs of nodes {n1, n2} ∈ (As × Aj)∪(Xs × Xj)∪(Xs × S)∪(S × Xj)∪(S × S) limit our selection of pairs to the combinations of where and {n1, n2} |n1 · | > 1 o w > 1 for any given pair of nodes, that pair is marked as a matching operator stands for the nodes of type XOR-split/join respectively, must be checked. As of the coloring algorithm applied to a single AND-split/join handle. their graphical representation can be colorized in a suitable way in order to must be found to determine a common color for operator nodes that are part of list of matching operator node pairs, where a given cluster contains all nodes more than one matching pair. This is done by building node clusters from the of all pairs sharing at least one common node. Figure 3 shows an application Since only one single color can be assigned to each node at a time, a way example of this clustering algorithm, resulting in the same color being used for multiple matching operator handles {t1,t7}, {t1,t5} and {t1,t10 }. porting the well-established "van der Aalst" notation[6]. The tool is maintained via Sourceforge, a common platform for the distributed development of free WoPeD is an open source, Java-based graphical editor for worko w nets supsoftware projects. Several publications have accompanied the emerging development of WoPeD [7, 8, 9]. In the newest release which is obtainable on the
Figure 3: Handle clustering example Figure 2: Example of distinct matching pairs marked in individual colors derived from the original graph by inserting a rst node n’ and G = (S, T , F ) Figure 4: A settings dialog allows the conguration of optical appearance sentation of the transformed worko w net. This transformed representation is the visual feedback of correct modelling, only node pairs that do not violate the colors must be re-used or the palette must be extended. Finally, the visual inicted changes. If a relevant change is detected, the coloring algorithm is In enabled mode, the worko w net graph is constantly monitored for userthat have not been identied as members of any pair or cluster by the algorithm. a second node n for each node , and then creating an arc connecting n ∈ S ∪ T feature is disabled. executed, producing a possibly new set of node clusters. Each cluster receives an individual color from the palette until all colors are in use. If this happens, Their graphical representation matches that of standard nodes when the coloring There is a special neutral color (usually white) that is used for all nodes representation of the worko w net is updated using the new colors. To enhance rules of well-handledness are considered for coloring.
The coloring algorithm has been implemented on top of a simplied repreto allow its application to the generalized problem of detecting PT/TP-handles can clearly distinguish from each other is fairly limited. A possible solution for the amount of distinguishable handle clusters for complex worko w nets with this could involve the assignment of special patterns in addition to plain palette replaces the structural worko w net analysis functionality of WoPeD, allowing One shortcoming of our approach is the fact that the number of colors a human The coloring algorithm has been implemented in a sucien tly generic way as and thus control-o w errors in worko w nets. Our implementation therefore also more existing clusters than palette color entries.
PT/TP-handle detection without falling back to external tools as Woan. colors (e. g. hatched, striped or plaid). Such patterns could be used to extend 1. {t1, t7} 3. {t1, t10} 2. {t1, t5} 4 Conclusion
node pairs detected