András Benczúr

In the document-centric modeling of information systems, the flow of data between individual documents and the collections stored in the database plays an important role. The types of data that can be stored in the collections and their constraints are given by the data models supported by the database management software. We show the semantically fundamental usage difference between the documents and the database. In addition to managing relational rows, the relational data model that is the most important starting point also contains a basic document type, namely the tabular document type, as a representation of a relation consisting of relatively few rows. With this dual task in mind, we introduce the extended relational model. In the standard relational model, each relation name identifies a collection of occurrences of a single row type. Therefore, in schema-level instructions and operations, each relation name/table name has a fixed set of attributes (ordered or unordered). In our paper, we introduce a collection containing tables of different but similar schemas. Actions can be specified at this level, which applies to several tables at the same time. The similarity of the schemes is given by belonging to a formal language over a finite set of attribute names. Every sentence of a given formal language can be a potential schema. An attribute name can therefore occur more than once in a specific schema, and the order is fixed. An instance of a schema collection consists of a finite number of table types. This is called an extended relation. Among the formal languages, we first discuss the use of regular languages. In the case of context-free languages, we use the language's terminal and non-terminal symbols as attribute names. With this, embedded relational schemas can also be handled. We use graph representations of formal languages as schema graphs. With the help of this, we specify the operations at the schema and instance level. The definition and implication problems of functional dependencies are investigated too. We show the close connection with the XML ELEMENT declaration. We also specify an implementation solution. After introduction, we shortly examine its use in the document centric modelling of information systems. A novel X-merge solution is specified between free documents and X-relations.

Hyper-graphs offer the opportunity to formulate logical statements about their components, for example, using Horn clauses. Several models of Information Systems can be represented using hyper-graphs as the workflows, i.e., the business processes. During the modeling of Information Systems, many constraints should be maintained during the development process. The models of Information Systems are complex objects, for this reason, the analysis of algorithms and graph structures that can support the consistency and integrity of models is an essential issue. A set of interdependencies between models and components of architecture can be formulated by functional dependencies and can be investigated via algorithmic methods. Information Systems can be perceived as overarching documents that includes data collections; documents to be processed; and representations of business processes, activities, and services. Whe selecting and working out an appropriate method encoding of artifacts in Information Systems, the complex structure can be represented using hyper-graphs. This representation enables the application of various model-checking, verification, and validation tools that are based on formal approaches. This paper describes the proposed representations in different situations using hyper-graphs, moreover, the formal, algorithmic-based model-checking methods that are coupled with the representations. The model-checking methods are realized by algorithms that are grounded in graph-theoretical approaches and tailored to the specificity of hyper-graphs. Finally, the possible applications in a real-life enterprise environment are outlined.

To tackle the issues of semantic collision and inconsistencies between ontologies and the original data model while learning ontology from relational database (RDB), a semi-automatic semantic consistency checking method based on graph intermediate representation and model checking is presented. Initially, the W-Graph, as an intermediate model between databases and ontologies, was utilized to formalize the semantic correspondences between databases and ontologies, which were then transformed into the Kripke structure and eventually encoded with the SMV program. Meanwhile, description logics (DLs) were employed to formalize the semantic specifications of the learned ontologies, since the OWL DL showed good semantic compatibility and the DLs presented an excellent expressivity. Thereafter, the specifications were converted into a computer tree logic (CTL) formula to improve machine readability. Furthermore, the task of checking semantic consistency could be converted into a global model checking problem that could be solved automatically by the symbolic model checker. Moreover, an example is given to demonstrate the specific process of formalizing and checking the semantic consistency between learned ontologies and RDB, and a verification experiment was conducted to verify the feasibility of the presented method. The results showed that the presented method could correctly check and identify the different kinds of inconsistencies between learned ontologies and its original data model.

Most recently, the concept of business documents has started to play double role. On one hand, a business document (word processing text or calculation sheet) can be used as specification tool, on the other hand the business document is an immanent constituent of business processes, thereby essential component of business information systems. The recent tendency is that the majority of documents and their contents within business information systems remain in semi-structured format and a lesser part of documents is transformed into schemas of structured databases. In order to keep the emerging situation in hand, we suggest the creation (1) a theoretical framework for modeling business Information Systems and (2) a design method for practical application based on the theoretical model that provides the structuring principles. The modeling approach that focuses on documents and their interrelationships with business processes assists in perceiving the activities of modern information systems.