Domain-specific definition

Definition / An expert system is a computer program that manipulates large amounts of symboHc knowledge using quaUtative techniques, to solve problems that can otherwise be solved only by expert human problem solvers. Expert systems capture the human problem solver s expertise in the form of domain-specific knowledge and domain-independent problem-solving strategies. 

The extension on the meta level comprises two parts First, graph- and integration-related definitions are added. These are used by all integration rule sets. Second, domain-specific extensions can be made. They can facilitate the definition of integration models when being combined with domain-specific... 

Before any further definitions can be made, the documents to be integrated have to be modeled on type level as described above, which is not shown in this figure. Next, link types have to be defined on tjrpe level that declare types for possible correspondences on the abstract instance level. Again, for both tasks domain-specific knowledge has to be used. 

Domain-specific knowledge is formalized by a process model definition (cf. Sect. 2.4) which constrains the process model instances to be maintained at project runtime. As a consequence, the manager may compose task nets from predefined types and relationships. The process model definition is represented in the Unified Modeling Language UML [560]), a wide-spread standard notation for object-oriented modeling. A process model is defined on the type level by a class diagram which has been adapted to the underlying process meta model for dynamic task nets [388, 389]. 

However, a management configuration should not evolve in arbitrary ways. There are domain-specific constraints which have to be met. In particular, activities can be classified into types such as requirements definition, design, simulation, etc. (likewise for products and resources). Furthermore, the way how activities are connected is constrained as well. For example, a flowsheet can be designed only after the requirements have been defined. Such domain-specific constraints should be taken into account such that they restrict the freedom of evolution. 

Before the AHEAD system is used to manage some actual design project, it is provided with a domain-specific process model definition (cf. Sect. 2.4) which should capture the conceptual design and basic engineering of arbitrary chemical design processes to meet our own demands in the IMPROVE project. 

From the UML model, code is generated to customize the functionality provided by the AHEAD system. For example, the project manager may instantiate only the domain-specific classes and associations defined in the class diagrams. The core system as presented in this section enforces consistency with the process model definition. In this way, we can make sure that design proceeds according to the domain-specific model. A more flexible approach will be discussed in the next section (extending process evolution beyond consistency-preserving instance-level evolution). 

On the partially typed level, the process modeler is capable of defining domain-specific types of tasks and relationships, but he also permits the use of unconstrained types on the instance level. In particular, this allows to leave out exceptions like feedbacks in the definition. When feedback does occur during enactment (e.g., a design error is detected during implementation), it can be handled by instantiating an unconstrained type of feedback flow without necessarily changing the process model definition. 

The planned workflow management system for AMB-Informatik meets both issues. First, it provides support for the definition at build-time of work-flows and conformance rules via the conformance rules editor. Second, laws or domain specific regulations are enforced at runtime by checking dynamic changes of a workflow instance by a conformance checker before these changes actually take effect in the workflow instance. 

In the context of the NMR-SIM simulation, the recording of a one-dimensional experiment consists of the definition of the spin system, the pulse sequence and the experiment parameters. The result of the simulation is a FID that is loaded into the ID WIN-NMR processing program. Both the time domain and the frequency domain data may be processed using a variety of domain specific mathematical functions. 

Without any semantic (or domain specific) knowledge of the system it is possible to create a block definition diagram in SysML, see Figure 3. By defining closed areas in the original diagram (Figure 1) to be components, i.e. blocks of the BDD, it is possible to create the BDD based on syntactic decisions. 

By definition, PCK is subject- and domain-specific (Shulman, 1986, 1987). The idea is that there cannot be one common strategy that can be operated on each different content in the teaching of language, science or history. The teacher needs to select and adapt teaching approaches and methods for each specific situation, in their subject and with respect to the learners and to the individual content. Geddis (1993) described the situation as ... 

From the definition of specific speed (eqs. 9 and 10), it follows that reciprocating pumps operate at high pressures and low flow rates. Conversely, centrifugal pumps are appHed at lower pressures and higher flow rates. Many rotary pumps are selected for viscous Hquids having pressures equal to or less than, and capacities lower than, centrifugal pumps. However, these limits are relative and a gray area exists as some pump types cross boundaries into the domain of other types. 

The next few steps are very similar to those required in any software project. One of the first stages is the clear definition of the knowledge domain. It must be clear which problems the expert system must solve. It is at this stage not the intention to define how this can be done. Clarity and specificity must be the major guides here. Fuzziness at this stage will, more than in classical software projects, have to be paid for later when different interpretations cause misunderstandings. Equally important is the clear definition of the end user(s). An expert system set up as decision support tool for professionals is totally different from an expert system that can be used as a training support for less professional people. 

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