## 4 Case Studies: Using DSM to Address GPM Limitations in DPD
### Modeling a Process with GPM (OPM)
This is also where unique, idiosyncratic modeling preferences start to affect the resulting model. Figures 2-8 show seven modeling alternatives that are all correct with respect to OPM syntax (but not necessarily with the semantics of the process description). The OPL descriptions may help readers to reveal the nuances between the modeling alternatives, each employing a different scheme of using OPM notation and concepts. The first three present direct connectivity between object and process, using the different types of links available in OPM, to connect such model elements: in Figure 2, the process (Manufacturing) \"requires\" an object (ComponentA Specification), using OPM's instrument link, and \"yields\" another object (ComponentA), using OPM's result link; in Figure 3, the process \"occurs if\" an object is \"in existent\", using OPM's instrument condition link and \"yields\" another object (using the result link); in Figure 4, the process \"consumes\" an object, using OPM's consumption link, and \"yields\" another (using the result link). Figure 3: Linking objects and process, option #2. Figure 2: Linking objects and process, option #1. Figure 4: Linking objects and process, option #3. Figure 5: Linking objects and process, option #4. Figure 6: Linking objects and process, option #5. The next three alternatives are represented in Figures 5-7--each being variation on Figures 2-4, respectively--employ links between a process and its resulting object's state, i.e., the process now yields an object (ComponentA) in a specific state (Produced), using the result link with a state element as its target (as opposed to its use in Figures 2-4, in which its target is an object element). The last alternative (Figure 8) shows a more rigorous alternative, with the process only using objects in defined states for both outputs and inputs, i.e., the process now \"requires\" an object in a specific state (instrument link from state element associated with an object element to the process; and since the state designation of the input is not specified explicitly, it is denoted as \"0\"). The multiplicity introduced by these alternatives clearly demonstrates that OPM is lacking with respect to ontological clarity, in accordance with the theoretical findings by [PERSON] et al. [43]. Specifically, OPM allows modeling the creation of an object (as an ontological concept) by using the result-link from a process to the object (the first three alternatives, in which \"Manufacturing yields ComponentA\") or by using the result-link from a process to a specific state of the object (last four alternatives, in which \"Manufacturing yields Produced ComponentA\"). Similarly, the ontological concept of using of objects by processes is allowed in the form of an instrument-link from object to process (Figure 2) or from state to process (Figure 8), or in the form of a consumption-link (Figure 4); we note that while the first two options are semantically valid with respect to the process description, the third option is not. Modeling using more than one of the available alternatives can result in inconsistent and incomparable model segments; and it is, therefore, expected from the user-designer to select and use a single alternative, in order to produce a coherent, rigorous model. Figure 8: Linking objects and process, option #7. Figure 7: Linking objects and process, option #6.