Johann Eder

Logic and Databases

Logic and databases have gone a long way together since the advent of relational databases. Already the first basic query languages for relational databases beside relational algebra — tuple calculus and domain calculus — are actually a subset of first order predicate logic. Furthermore logic proved to be very adequate for establishing a sound theory for relational databases.

Time Management in Workflow Systems

Management of workflow processes is more than just enactment of process activities according to business rules. Time management functionality should be provided to control the lifecycle of processes. Time management should address planning of workflow executions in time, provide various estimates about activity execution durations, avoid violations of deadlines assigned to activities and the entire process, and react to deadline violations when they occur. In this paper we describe how time information can be captured in the workflow definition, and we propose a technique for calculating internal activity deadlines with the goal to meet the overall deadlines during process execution.

Creation and management of versions in multiversion data warehouse

A data warehouse (DW) provides an information for analytical processing, decision making, and data mining tools. On the one hand, the structure and content of a data warehouse reflects a real world, i.e. data stored in a DW come from real production systems. On the other hand, a DW and its tools may be used for predicting trends and simulating a virtual business scenarios. This activity is often called the what-if analysis. Traditional DW systems have static structure of their schemas and relationships between data, and therefore they are not able to support any dynamics in their structure and content. For these purposes, multiversion data warehouses seem to be very promising. In this paper we present a concept and an ongoing implementation of a multiversion data warehouse that is capable of handling changes in the structure of its schema as well as simulating alternative business scenarios.

Changes of Dimension Data in Temporal Data Warehouses

Time is one of the dimensions we frequently find in data warehouses allowing comparisons of data in different periods. In current multi-dimensional data warehouse technology changes of dimension data cannot be represented adequately since all dimensions are (implicitly) considered as orthogonal. We propose an extension of the multi-dimensional data model employed in data warehouses allowing to cope correctly with changes in dimension data: a temporal multi-dimensional data model allows the registration of temporal versions of dimension data. Mappings are provided to transfer data between different temporal versions of the instances of dimensions and enable the system to correctly answer queries spanning multiple periods and thus different versions of dimension data.

Temporal Conformance of Federated Choreographies

Web service composition is a new way for implementing business processes. In particular, a choreography supports modeling and enactment of interorganizational business processes consisting of autonomous organizations. Temporal constraints are important quality criteria. We propose a technique for modeling temporal constraints in choreographies and orchestrations, checking whether the orchestrations satisfy the temporal constraints of a choreography and compute internal deadlines for the activities in an interorganizational workflow.

A Data Warehouse for Workflow Logs

Workflow Logs provide a very valuable source of information about the actual execution of business processes in organizations. We propose to use data warehouse technology to exploit this information resources for organizational developments, monitoring and process improvements. We introduce a general data warehouse design for workflow warehouses and discuss the results from an industrial case study showing the validity of this approach.

Personal schedules for workflow systems

Personal schedules allow workflow participants to improve their performance of activity executions. Participants are no longer surprised by the entries in their work-lists but receive advance information about (potential) future activity assignments, allowing better possibilities for work-planning. The personal schedule system is based on a probabilistic workflow time management system using duration histograms. A personal schedule collects future activity assignments together with their probability and their timing requirements and allows to analyze the workload of a participant and to support the scheduling of activities with the goal of reduced turn-around times and reduced number of violations of temporal constraints.

Temporal Modeling of Workflows with Conditional Execution Paths

In this paper, we present a novel technique for modeling, checking, and enforcing temporal constraints in workflow processes containing conditionally executed activities. Existing workflow time modeling proposals either do not discriminate between time constraints that apply to disparate execution paths, or they treat every execution path independently. Consequently, superfluous time constraint violations may be detected at modeling time, even when each execution path does not violate any constraints. In addition, scheduling conflicts during process execution may not be detected for activities that are common to multiple execution paths. Our approach addresses these problems by (partially) unfolding the workflow graph associated with a process that contains conditionally executed activities and, then, incorporating the temporal constraints in the time calculations performed on the unfolded graph.

The Genome Austria Tissue Bank (GATiB).

In the context of the Austrian Genome Program, a tissue bank is being established (Genome Austria Tissue Bank, GATiB) which is based on a collection of diseased and corresponding normal tissues representing a great variety of diseases at their natural frequency of occurrence from a non-selected Central European population of more than 700,000 patients. Major emphasis is put on annotation of archival tissue with comprehensive clinical data, including follow-up data. A specific IT infrastructure supports sample annotation, tracking of sample usage as well as sample and data storage. Innovative data protection tools were developed which prevent sample donor re-identification, particularly if detailed medical and genetic data are combined. For quality control of old archival tissues, new techniques were established to check RNA quality and antigen stability. Since 2003, GATiB has changed from a population-based tissue bank to a disease-focused biobank comprising major cancers such as colon, breast, liver, as well as metabolic liver diseases and organs affected by the metabolic syndrome. Prospectively collected tissues are associated with blood samples and detailed data on the sample donor’s disease, lifestyle and environmental exposure, following standard operating procedures. Major emphasis is also placed on ethical, legal and social issues (ELSI) related to biobanks. A specific research project and an international advisory board ensure the proper embedding of GATiB in society and facilitate international networking.

Towards an Automatic Integration of Statecharts

The integration of statecharts is part of an integration methodology for object oriented views. Statecharts are the most important language for the representation of the behaviour of objects and are used in many object oriented modeling techniques, e.g. in UML ([23]). In this paper we focus on the situation where the behaviour of an object type is represented in several statecharts, which have to be integrated into a single statechart. The presented approach allows an automatic integration process but gives the designer possibilities to make own decisions to guide the integration process and to achieve qualitative design goals.