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The W3C XML Schema recommendation defines the structure and data types for XML documents. XML Schema lacks explicit support for timevarying XML documents. Users have to resort to ad hoc, non-standard mechanisms to create schemas for time-varying XML documents. This paper presents a data model and architecture, called τXSchema, for creating a temporal schema(More)
The W3C XML Schema recommendation defines the structure and data types for XML documents, but lacks explicit support for time-varying XML documents or for a time-varying schema. In previous work we introduced \tauXSchema which is an infrastructure and suite of tools to support the creation and validation of time-varying documents, without requiring any(More)
The W3C XML Schema recommendation defines the structure and data types for XML documents, but lacks explicit support for time-varying XML documents or for a time-varying schema. In previous work we introduced τXSchema which is an infrastructure and suite of tools to support the creation and validation of time-varying documents, without requiring any changes(More)
If past versions of XML documents are retained, what of the various integrity constraints defined in XML Schema on those documents? This paper describes how to interpret such constraints as sequenced constraints, applicable at each point in time. We also consider how to add new variants that apply across time, so-called nonsequenced constraints. Our(More)
by faiz currim and sudha ram conceptually modeling Windows and bounds for space and time in database constraints Yet, in the development of spatial and temporal applications, we see that few constraints are typically modeled during conceptual database design. In contrast, few spatio-temporal constraints are modeled during conceptual database design. We feel(More)
In aspect-oriented programming (AOP) a cross-cutting concern is implemented in an aspect. An aspect weaver blends code from the aspect into a program’s code at programmer-specified cut points, yielding an aspectenhanced program. In this paper we apply some of the concepts from the AOP paradigm to data. Like code, data also has cross-cutting concerns such as(More)
When web servers publish data formatted in XML, only the current state of the data is (generally) published. But data evolves over time as it is updated. Capturing that evolution is vital to recovering past versions, tracking changes, and evaluating temporal queries. This paper presents a system to build a temporal data collection, which records the history(More)
Wireless technology is steadily improving the access and cost-effectiveness of healthcare data management. With the growth in information access, comes the challenge of maintaining patient record privacy and security. Our work develops an algorithm to evaluate ad-hoc user queries against database policies. We consider an efficient evaluation algorithm(More)