Facilitating data-metadata transformation by domain specialists in a web-based information system using simple correspondences

We seek to empower domain specialists and non-technical web designers to be able to design and configure their system directly, without necessarily requiring interaction with a software developer or DB specialist. We observe that structured information shown on a web page presents a conceptual model of the information shown; and, that such web pages make a variety of choices regarding whether or not application information is presented in the data (with or without schema labels) or in the metadata (schema). Also, the same application may present the same data in different schemas on different pages. In this paper, we extend our earlier work—on providing generic widgets for structured information that can be easily used and configured by domain specialists—to also include data/metadata transformation. Thus, we put data/metadata transformation (from one conceptual model to another) in the hands of domain specialists without database expertise. The contributions of this paper are: showing how our approach can be used to support data/metadata transformation in both directions and demonstrating this capability in a non-trivial case study. The paper also provides evidence that non-expert users can successfully provide simple correspondences through the results of a small-scale user study

Change cases: Use cases that identify future requirements

Evolution of software systems is prompted by all sorts of changes. This paper demonstrates how the use case, a well known construct in object-oriented analysis, is adapted to form the change case, to identify and articulate anticipated system changes. A change case provides the ability to identify and incorporate expected future change into a design to enhance the long-term robustness of that design. In this paper, we define change cases and demonstrate how change cases are captured by the analyst. We present examples to illustrate how change cases can influence present system design and point the way toward designs that more easily accommodate expected future changes. Change cases can be effectively employed in the context of any methodology that supports use cases and traceability links.

Support for Schema Evolution in Data Stream Management Systems

Unlike Database Management Systems (DBMSs), Data Stream Management Systems (DSMSs) do not evaluate queries over static data sets — rather, they continuously produce result streams to standing queries, and often operate in a context where any interruption can lead to data loss. Support for schema evolution in such an environment is currently unaddressed. In this work we address evolution in DSMSs by introducing a new element to streams, called an accent, that precedes and describes an evolution. We characterize how a subset of commonly used query operators in DSMS act on and propagate accents with respect to three evolution primitives: Add Attribute, Drop Attribute, and Alter Data