Organize Your Life with Nepomuk
When you build a house, you cannot start with the paint, fancy windows and doorbell. Instead, you spend a lot of time digging in the ground, disturbing the neighbors and making little visible progress while you lay the foundation. It has been much the same with Nepomuk, the Semantic Desktop technology of the KDE platform. Work has been going on for a long time beneath the surface, causing occasional disruption—such as file indexing slowing down the rest of your desktop—with little visible progress. However, the foundations now are solid, the main structures are in place, and KDE's developers are adding features that make Nepomuk useful for you, right now.
So, what can Nepomuk actually do for you?
The first thing Nepomuk offers is file searching integrated into your KDE applications. If your distribution has enabled Nepomuk, files also can be tagged and rated from KDE's Dolphin file manager. You can search for files simply by typing a query into Dolphin's search box, which brings up results and a panel of basic options that make it easy to refine the search. These enable you to limit searching to the current folder and let you choose whether to search everything, text documents (including OpenDocument texts and PDFs), images or filenames. When you have identified the files you want, you can use the Save button to add the search query to your Places panel on the left of the Dolphin window, making the search available in the future via a single click. The saved search also is available in the file chooser dialog of all KDE applications.
What Is This Thing Called Nepomuk?
Nepomuk (also known as the Networked Environment for Personalized, Ontology-based Management of Unified Knowledge) began as a research project funded by the European Union to explore better ways of managing, understanding and sharing desktop information. It attracted participation from corporations, such as IBM and Linux vendor Mandriva, in addition to involvement from the National University of Ireland.
The initial project ran from 2006 to 2008, during which time a reference implementation was written in Java. Mandriva and KDE have since worked on integrating the ideas into KDE software, retaining the name Nepomuk.
Practical use of the technology required a high-performance file indexer and query database. Initially, Nepomuk's own Java-based Sesame query framework was used in the KDE implementation, but its reliance on Java led to packaging problems for some distributions, and KDE switched to Virtuoso in 2009. No longer held back by these technical constraints, the main barriers to making greater use of Nepomuk in KDE software have been removed.
You can access additional search options in Dolphin 1.5 (part of KDE software compilation 4.5) by clicking the green + button. These provide filtering based on file modification date, size, tags or rating. You can continue to add and combine additional filters until you have isolated the exact files you want—for example, by limiting the search to files with a particular tag that have not been modified since a particular date. You also can use the filters directly without any search terms.
When Nepomuk first came to KDE software, it lacked a good graphical search interface to expose its capabilities. Nepomuk always has offered the ability to construct complex search queries using a query language, such as SPARQL. You could, and still can, enter queries in this way using Dolphin. Click on the breadcrumbs above the search results to access Dolphin's editable location bar, view the query that was used to generate the results and edit it directly. However, many users do not have an intimate knowledge of the query language constructs and would consider such an approach better suited to the command line than a graphical file manager. The search interface in Dolphin 1.5 graphically exposed many of Nepomuk's search capabilities for the first time.
Peter Penz, Dolphin's lead developer, still sees problems with the search interface in Dolphin 1.5: “It just takes way too many clicks to specify a query.” KDE developers, including Peter and Mandriva's Sebastian Trüg have been grappling with the problem of making a good graphical interface that exposes the power of Nepomuk searches in a more convenient manner. In 2009, Alessandro Sivieri began work on “faceted browsing”, an approach to the problem that provides panels of search filters in the file manager sidebar, resulting in his Sembrowser prototype (see Resources). Now, these ideas have come together to provide a faceted browsing sidebar in Dolphin 1.6 (part of KDE software compilation 4.6) that appears when you start a search and makes additional filters available with single clicks. Faceted browsing also will be integrated into the KDE platform, making it available for other KDE applications to use.
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