computer science

NEPOMUK (software)

NEPOMUK (software) is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand NEPOMUK (software) rather than just read about it. In short: NEPOMUK (Networked Environment for Personal, Ontology-based Management of Unified Knowledge) is an open-source software specification that is concerned with the development of a social semantic desktop that enriches and interconnects data from different desktop applications using semantic metadata stored as Resource Description Framework (RDF). Between 2006 and 2008 it was funded by a European Union research project…

Key takeaways

NEPOMUK (software) belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NEPOMUK (software) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NEPOMUK (software) from memory before moving on to harder problems.

Reference excerpt

NEPOMUK (Networked Environment for Personal, Ontology-based Management of Unified Knowledge) is an open-source software specification that is concerned with the development of a social semantic desktop that enriches and interconnects data from different desktop applications using semantic metadata stored as Resource Description Framework (RDF). Between 2006 and 2008 it was funded by a European Union research project of the same name that grouped together industrial and academic actors to develop various Semantic Desktop technologies.

Implementations Three active implementations of NEPOMUK exist: A C++/KDE-based variant, a Java-based variant, and a commercial version. More versions were created during the EU project between 2006 and 2008, some active beyond the project.

KDE NEPOMUK-KDE was originally featured as one of the newer technologies in KDE Software Compilation 4. It used Soprano as the main RDF data storage and parsing library, while handling ontology imports through the Redland RDF Application Framework Raptor parser plug-in and the storage plug-in; all RDF data was stored by Virtuoso Universal Server which also handled full-text indexing. On a technical level, NEPOMUK-KDE allowed associating metadata to various items present on a normal user's desktop such as files, bookmarks, e-mails, and calendar entries. Metadata could be arbitrary RDF. Tagging is the most user-visible metadata application. As the KDE SC 4 series of releases progressed, it became apparent that NEPOMUK was not delivering the performance and user experience that had initially been anticipated. As a result of this, in KDE SC 4.13 a new indexing and semantic search technology Baloo was introduced, with a short transition period allowing applications to be ported and data to be migrated before the removal of NEPOMUK. Baloo initially used SQLite but currently uses LMDB for storage, and Xapian for searching.

Zeitgeist The Zeitgeist framework, used by GNOME and Ubuntu's Unity user interface, uses the NEPOMUK ontology, as does the Tracker search engine.

Java The Java-based implementation of NEPOMUK was finished at the end of 2008 and served as a proof-of-concept environment for several novel semantic desktop techniques. It features its own frontend (PSEW) that integrates search, browsing, recommendation, and peer-to-peer functionality. The Java implementation uses the Sesame RDF store and the Aperture framework for integrating with other desktop applications such as mail clients and browsers. A number of artifacts have been created in the context of the Java research implementation:

WikiModel

Refinder by Gnowsis Implementation of the commercial Software as a service product Refinder started in 2009 and a limited beta-version was released in December 2010. Refinder was developed by Gnowsis, a spin-off company of the German Research Centre for Artificial Intelligence (DFKI) (project lead in the NEPOMUK EU project). The start-up was shut down in late 2013, with no plans to make the implementation code available. Refinder uses the same data formats as the other implementations, but using Software as a service instead of the desktop approach of the other implementations.

Data formats PIMO – the data format used for describing a Personal Information Model, describing Persons, Projects, Topics, Events, etc., also used in NEPOMUK-KDE. NIE – the NEPOMUK Information Element Ontology (and the associated ontologies NFO etc.), describing resources on a desktop (files, mails, etc.)

Worked examples

Example 1 — a first encounter with NEPOMUK (software)

Start with the simplest possible case. Write down what NEPOMUK (software) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to NEPOMUK (software) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about NEPOMUK (software) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of NEPOMUK (software)

In research: NEPOMUK (software) appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses NEPOMUK (software) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: NEPOMUK (software) is common in secondary-school and first-year university syllabi. It links to neighbouring topics KDE Frameworks, KDE Platform, Personal information managers, so understanding it makes those chapters shorter.
In everyday life: Look for NEPOMUK (software) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study NEPOMUK (software) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NEPOMUK (software) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain NEPOMUK (software) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NEPOMUK (software) in simple terms?

Why does NEPOMUK (software) matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study NEPOMUK (software)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on NEPOMUK (software).