medical researchers for tools that simplify the process of managing large collections of multimedia data. We have developed the Query-By-Context repository.
Query-By-Context: A Framework for Modeling and Navigating Multimedia Research Data Rex M. Jakobovits and James F. Brinkley Structural Informatics Group Departments of Biological Structure and Computer Science & Engineering University of Washington, Seattle Background. There is a growing demand among medical researchers for tools that simplify the process of managing large collections of multimedia data. We have developed the Query-By-Context repository system, a framework for modeling, acquiring, managing, and navigating through multimedia information. The system allows a programmer to model domain knowledge as context-sensitive views, from which web pages are dynamically generated in response to user queries.
To accommodate multiple user contexts, the UserClass of the query session is accessible from within the ViewClass methods, to allow the ViewClass designer to provide custom-tailored views. For example, to maintain patient privacy, the patient's LabelView might display the patient's name for privileged users, and only show a patient's research number for public users. A simple switch statement can thus be used to enforce privacy at every level of the system.
The Query-By-Context framework is SystenL implemented using the Web-Interfacing Repository Manager', a Perl-based object-relational multimedia database system. Modeling multimedia knowledge can be simplified by recognizing multiple types of context that affect how an object appears. Three kinds of context are supported by the system: ViewClass context, which defines what kind of object we are looking at, UserClass context, which identifies the point of view from which the object is being observed, and Subject context, which identifies the particular instance(s) that are being viewed.
Results. The Query-By-Context framework was used to implement a Brain Mapping Information System for managing cortical stimulation data Patient demoobtained during neurosurgery. graphics, MRI exams, surgeries, intra-operative photographs, stimulation studies, and 3D brain models are all hierarchically modeled as schemas and ViewClasses, using 1300 lines of perl code. Multiple privacy contexts are supported via the UserClass context facility. A Data Analysis Console allows a researcher to split patients into demographic groups and compare the distributions of critical stimulation sites.
Domain knowledge is modeled as a set of Repository Object class definitions. Each class definition consists of two parts: a Schema and a ViewClass. The Schema consists of a type name and a list of attribute names and their corresponding types. The ViewClass consists of three functions that declare how a subject should appear at three abstraction levels: LabelView (in the context of a string), RowView (in the context of a collection of objects), and FullView (in the context of a single focused object). The LabelView returns a string (e.g. a patient's name), the RowView returns a list of values (to be used in an HTML table), and the FullView returns a full HTML page. The repository system provides an application programmer's interface (the Web API), that allows easy definition of HTML code for generating ViewClasses. The ViewClass methods can be constructed hierarchically. For example, the RowView for a patient might include the patient's LabelView as its first item.
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Conclusion. The Query-By-Context framework proved to be an effective tool for modeling complex medical research data. By explicitly modeling context-sensitive ViewClasses and UserClasses, the process of developing user interfaces was greatly simplified, and it is simple to customize the user interfaces and extend the schemas as need arises. Our next task is to develop a workflow management system by providing facilities to model a fourth kind of context: the Life Cycle of a repository object. Acknowledgements & References This research was supported by Human Brain Project grant RO1 DC023 10. 1. Jakobovits, R.M. and Brinkley, J.F. Managing medical research data with a web-interfacing repository manager. In Proceedings, Annual Fall Symposium, pages 454-458, American Medical Informatics Association, 1997.
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