In the ADEPT project we have been working on the design and implementation of next generation process management software. Based on a conceptual framework for dynamic process changes, on novel process support functions, and on advanced implementation concepts, the developed system enables the realization of adaptive, process-aware information systems (PAIS). Basically, process changes can take place at the type as well as the instance level: changes of single process instances may have to be carried out in an ad-hoc manner and must not affect system robustness and consistency. Process type changes, in turn, must be quickly accomplished in order to adapt the PAIS to business process changes. ADEPT2 offers powerful concepts for modeling, analyzing, and verifying process schemes. Particularly, it ensures schema correctness, like the absence of deadlock-causing cycles or erroneous data flows. This, in turn, constitutes an important prerequisite for dynamic process changes as well. ADEPT2 supports both ad-hoc changes of single process instances and the propagation of process type changes to running instances.

For enterprise-wide and cross-organizational process-oriented applications, the execution of workflows (WF) may generate a very high load. This load may affect WF servers as well as the underlying communication network. To improve system scalability, several approaches for distributed WF management have been proposed in the literature. They have in common that different partitions of a WF instance graph may be controlled by different WF servers from different subnets. The control over a particular WF instance, therefore, may be transferred from one WF server to another during run-time if this helps to reduce the overall communication load. Thus far, such distributed approaches assume that exactly one WF server resides in each subnet. A single server per subnet, however, may become overloaded. In this paper, we present and verify a novel approach for replicating WF servers in a distributed workflow management system. It enables an arbitrary and changeable distribution of the load to the WF servers of the same subnet, without requiring additional communication.

The management of product-related data in a uniform and consistent way is a big challenge for many manufacturing enterprises, especially the large ones, like DaimlerChrysler. So-called product data management (PDM) systems are a promising way to achieve this goal. For various reasons, PDM systems often sit on top of a relational DBMS, using it (more or less) as a simple record manager. User interactions with the PDM systems are translated into a series of SQL queries. This does not cause too much harm when the DBMS and PDM system are located in the same local area network, with high bandwidth and short latency times. The picture may change dramatically, however, if the users are working in geographically distributed environments. Response times may rise by orders of magnitude, e.g. from 1-2 minutes in the local context to 30 minutes and even more in the "inter-continental" context. This paper shows how a more sophisticated utilization of the (advanced) SQL features coming along with SQL:1999 can help to cut down response times significantly.

If the number of users within a workflow management system (WFMS) increases, a central workflow server (WF-server) and a single local area network (LAN) may become overloaded. The approach presented in the paper describes an execution environment which is able to manage a growing number of users by adding new servers and subnets. The basic idea is to decompose processes into parts which are controlled by different WF-servers. That is, during the execution of a workflow instance its execution (step) control may migrate from one WF-server to another. By selecting the appropriate physical servers (for hosting the WF-servers) in the appropriate LANs, communication costs and individual WF-server workload can be reduced significantly.

The model of flexible relations supports heterogeneous sets of tuples in a strongly typed way. The elegance of the standard relational model is presented by using a single, generic scheme constructor. In each model supporting structural variants the shape of some part of a heterogeneous scheme may be determined by the contents of some other part of the scheme. We formalize this relationship by a certain kind of integrity constraint we have called "attribute dependency" (AD). We motivate how ADs can be used, besides their application in type and integrity checking, to incorporate record subtyping into our extended relational model. Moreover, we show that ADs yield a stronger assertion than the traditional record subtyping rub as they consider interdependencies among refinements. We discuss how ADs are related to query processing and how they may help to identify redundant operations.>

Medical guidelines play an increasing role in selecting diagnostic and therapeutic steps under the aspects of effectiveness, invasiveness, and costs. To work directly on patient data already available in electronic form, they should be integrated into a medical information system. In order to develop a “medical guideline module” (MGM) managing and applying guidelines to patients, a “knowledge level” representation of guidelines is necessary which reflects the structure of medical knowledge and matches medical processes. Furthermore, a direct transformation to the “symbol level” is needed. We use a nested, frame-like structure on the knowledge level and show that a classification-based knowledge representation system (CBKRS) is principally well suited for the symbol level. To facilitate the usage and to be independent of a particular CBKRS, we introduce an intermediate level called “intelligent object system” (IOS). It is developed by augmenting a simple data model for describing complex objects with prototypes and implications as a means to classify objects and to draw inferences based on this classification. Finally, the transformation of guidelines to prototypes and implications is described.

Recently, extensions for relational database management systems (DBMS) have been proposed to support also hierarchical structures (complex objects). These extensions have been mainly implemented on top of an existing DBMS. Such an approach leads to many disadvantages not only from the conceptual point of view but also from performance aspects. Thus paper reports on a 3-year effort to design and prototype a DBMS to support a generalized relational data model, called extended NF2 (Non First Normal Form) data model which treats flat relations, lists, and hierarchical structures in a uniform way. The logical data model, a language for this model, and alternatives for storage structures to implement generalized relations are presented and discussed.