Max Völkel:
Personal Knowledge Models
with Semantic Technologies

Conceptual Data Structures (CDS) is a unified meta-model for representing knowledge cues in varying degrees of granularity, structuredness, and formality.
CDS consists of:
(1) A simple, expressive data-model;
(2) A relation ontology which unifies the relations found in cognitive models of personal knowledge management tools, e. g., documents, mind-maps, hypertext, or semantic wikis.
(3) An interchange format for structured text.
Implemented prototypes have been evaluated.

Following the ideas of Vannevar Bush (1945) and Douglas Engelbart (1963), this thesis explores how computers can help humans to be more intelligent. More precisely, the idea is to reduce limitations of cognitive processes with the help of knowledge cues, which are external reminders about previously experienced internal knowledge. A knowledge cue is any kind of symbol, pattern or artefact, created with the intent to be used by its creator, to reevoke a previously experienced mental state, when used.
The main processes in creating, managing and using knowledge cues are analysed. Based on the resulting knowledge cue life-cycle, an economic analysis of costs and benefits in Personal Knowledge Management (PKM) processes is performed. The main result of this thesis is a meta-model for representing knowledge cues, which is called Conceptual Data Structures (CDS). It consists of three parts: (1) A simple, expressive data-model; (2) A small relation ontology which unifies the relations found in the cognitive models of tools used for PKM tasks, e. g., documents, mind-maps, hypertext, or semantic wikis. (3) An interchange format for structured text together with corresponding wiki syntax.
These three parts together allow representing knowledge cues in varying degrees of granularity (number and size of items), structuredness (relations between items), and formality (fraction of items typed with items from a meta-model) in a unified way.
The CDS model has been implemented in Java. Based on this reference implementation several tools for personal knowledge management have been created (one by the author of this work and two external tools). All three tools have been used in a comparative evaluation with 125 person-hours. In the evaluation, the Conceptual Data Structures (CDS) data model has successfully been used to represent and use (retrieve) artefacts in a uniform fashion that are in different degrees of formalisation. Although still research prototypes, the CDS Tools had interaction efficiency and usability ratings compared to Semantic MediaWiki (SMW). Using CDS Tools, users produced significantly more non-trivial triples than with SMW. The created Relation and concept hierarchies can be re-used in a semantic desktop.