We offer an exam review on Tuesday, 1

**March 2016, morning (09:00 to 12:00)**in our office H-1.38.

WS 2015/16

The final exams have been evaluated and the results have been submitted to the examination office.

We offer an exam review on Tuesday, 1** March 2016, morning (09:00 to 12:00)** in our office H-1.38.

We offer an exam review on Tuesday, 1

Dear students,

we would like to inform you that the final exam will take place:

**Friday, 12.02.2016 **
**10am - 12pm**
**HS 3**

**Wir wünschen Ihnen **
**Viel Erfolg! **

we would like to inform you that the final exam will take place:

- the exam time limit is 120 minutes
- please keep in mind that no additional materials are allowed
- please formulate your answers in short and precise sentences
- please write legibly

Due to travel and project obligations, we have to switch the lecture and the lab course this week (16./27.01.2016).

**Lecture**(originally on Tue, 26.1.2016, 1.30pm)- ->
**rescheduled to Wed, 27.1.2016, 9.15 am** **Lab Course**(originally on Wed, 27.1.2016, 9.15am)- ->
**rescheduled to TUE, 28.1.2016, 1.30 pm**

Thanks a lot for your consideration.

via http://www.gocomics.com/calvinandhobbes/ |

It is essential to ensure the quality of the ontology that you are going to develop. Simply for reasons of efficiency with respect to further refinement or additions. When working and discussing the examples with **OntoClean** in the lecture and the lab course, you have realized that it is important to have clear definitions of your concepts/classes. In our examples, we have treated the discussed ontologies always as rather general upper ontologies with the aim to represent the *'real' world in its entirety*...and as you might have noticed, this sometimes is more or less futile since we were not able to reach an agreement upon the interpretation of the represented classes.

Therefore, in real life applications of ontology engineering, always keep in mind the purpose of your ontology, the application for which the ontology is intended to be used. Keep your knowledge representations restricted to the intended purpose. If your application demands countries to be treated simply as geographical entities, you don't have to consider the administrative or legal structure of a country for your application. Thus, it should also not be necessarily considered in your knowledge representation -- or also in your evaluation.

The **OntoClean** methodology focusses on the taxonomic structure of an ontology, where the suborder relation is considered being a formal subsumption. Strictly speaking, if an individual is member of a class, it is necessarily also a member of the according superclass. To check the semantical consistency of your class taxonomy, all the classes are tagged with metaproperties (*Rigidity, Unity, Identity, and Dependency*). It is crucial that your metaproperties clearly reflect the intended meaning of the classes. If in doubt, always give an explanation/justification, why you have chosen a specific metaproperty. Then, you look for violations of the given OntoClean constraints for these metaproperties. Whenever you find a constraint violation, this is an indication either to change your ontology or to reconsider the definition (the meaning) of your ontology classes accordingly.

One comment on the exercise in the lab course today:

We should label the owl:Thing (the top concept in the DBpedia Ontology) with **-U**, since the instances of owl:Thing **do not have a common unity criterium**. Possibly there are also some classes subsumed by owl:Thing that contain entities which are *not necessarily considered a whole*, i.e. which must have the meta-property **~U** (anti-Unity), but this cannot be assumed for all the individuals of owl:Thing alike (and also for entity in the example from the slides, lecture 5.8). Instead, we have to choose the more general **-U** (no common unity criterium) for owl:Thing here.

Please find the Example Ontology file, we created in the lab course for the exercise Modelling the Facts in Protégé from exercise sheet 7.

You can find the same in the material folder as well.

You can find the same in the material folder as well.

© 2015 by Sidney Harris |

In the lab course today, we were discussing

Usually, atoms and atomic formulas are used equivalently in FOL to denote formulas that contain no logical connectives and quantifiers, or equivalently, formulas that do not contain any strict subformulas. Atoms (atomic formulas) are the simplest well-formed formulas in FOL.

For example, consider the following (composite) formula:

∀x. P (x) ∧ ∃y. Q (y, f (x)) ∨ ∃z. R (z)

where x,y,z denote variables, f denotes a function symbol, and P, Q, R denote predicates.

The atoms (atomic formulas) contained in this formula are:

- P (x)
- Q (y, f (x))
- R (z)

In the lecture slides, we only gave a brief summary for the definition of FOL based on examples. For an extensive definition of FOL, please refer to [1].

Thus, whenever we are talking about atoms, as e.g. when we were talking about rules, we refer to atomic formulas.

Then there was the question, **whether a function like e.g. mother(x) is an atom/atomic formula**?

The definition of an

- If P is a predicate symbol of arity k, and if t
_{1},...,t_{k}, are terms, then P(t_{1},...,t_{k}) is a formula. - (
**Negation**) For all formulas F, also ¬F is a formula - (
**Binary**Connectives) For all Formulas F,G, also F∧G,F∨G,F→ G,F↔G are formulas - (
**Quantifiers**) If x is a variable and F is a formula, then also ∀x.F and ∃x.F are formulas

A function alone is only considered a **term**, following the definition of an **FOL term**:

- all variables are terms
- If f is a function symbol of arity k, and if t
_{1},...,t_{k}, are terms, then f(t_{1},...,t_{k}) is also a term.

For a distinction, you may keep in mind that terms do not compute a truth value, a formula does.

[1] Uwe Schöning: Logik für Informatiker. Spektrum Akademischer Verlag, 2000

or in english:

[2] Uwe Schöning: Logic for computer scientists, Birkhäuser, 2008, also online available

The final exam will take place on

**Friday, February 12, 2016 – 10:00 AM to 12:00 PM**

The location will be announced.

The location will be announced.

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