**4. XOL example**

*Ontological Analyses in Science, Technology and Informatics*

**Name Function**

**42**

**3.4 Acceptable facet**

MAXIMUM-CARDINALITY

**Table 3.** *The facet of XOL.*

**Table 2.**

*The slots on slots of XOL.*

facet defined in OKBC-Lite.

Facet can also divide into two parts:

VALUE-TYPE Value can be class or

INVERSE Describe the slot

CARDINALITY Specifies the exact

• Own Facet (only state on current class or current KB)

• Template Facet (inherit from another class)

Different with slots on slots, facet is a restriction on the value of slot of individual. For instance, facet VALUE-TYPE and facet NUMERIC-MINIMUM describe the type of value of a slot and the minimum of value of a slot. **Table 3** is the acceptable

**Name Description Name Description**

DOMAIN Specifies the domain of the binary relation represented by a slot frame SLOT-VALUE-TYPE Specifies the classes of which values of a slot must be an instance

SLOT-CARDINALITY Specifies the exact number of values that may be asserted

SLOT-MAXIMUM-CARDINALITY Specifies the maximum number of values that may be

SLOT-MINIMUM-CARDINALITYNUMERIC Specifies the minimum number of values for a slot for

SLOT-NUMERIC-MAXIMUM Specifies a lower bound on the values of a slot for entities

SLOT-NUMERIC-MINIMUM Specifies an upper bound on the values of a slot for entities

SLOT-COLLECTION-TYPE Specifies whether multiple values of a slot are to be treated

for a slot for entities in the slot's domain

entities in the slot's domain

in the slot's domain

in the slot's domain

as a set, list, or bag

asserted for a slot for entities in the slot's domain

SLOT-INVERSE Specifies the inverse relation for a slot

MINIMUM-CARDINALITY

NUMERIC-MAXIMUM The class of all symbols A subclass of THING

the number-type values

Specifies upper bound on the number-type values

multiple values of a slot are to be treated as set/

NUMERIC-MINIMUM Specifies lower bound on

COLLECTION-TYPE Specifies whether

of slot

of a slot

list/bag.

multiclass or set of

relation is reverse and value is reverse

number of values asserted for a slot

Specifies the maximum number of values asserted for a slot

value

slot

Every XOL file must start with the following XML tab in the beginning. <? xml version="1.0"?><!DOCTYPE module SYSTEM "module.dtd">

As the whole KB's first description, 'module section' will illuminate some information (name, type of DB, in which package, etc.) about this KB.

<Module> /\*Every XOL file will start with a module mark \*/

<Name>name of this KB</Name>

<kb-type>which existing kb type</kb-type>

<package>self-defined package name</package>

The second section is 'class section.' In this section, we will introduce all these

KB's classes or inherit from other class by the tag 'subclass-of' or 'instance-of.'

<Class>

<Name>name of class</Name>

<Documentation>String-type description</Documentation>

[Other-option-slot] (Subclass-of | instance-of | etc.)

</Class>

The third section is 'slot section,' which declares all slots in the class and slots existing slot value in an individual, such as the class-name, class-documentation, and other-option slot.

<Slot>.

<Name>name of own slot or template slot</name>

<Documentation>description</documentation>

```
<Domain (or other slots on slots in Table 2)>.</Domain>
</Slot>
```
The last section generally is 'individual section.' It contains all instances and their values in each slot. Also, it declares restriction of value of slot and slot-values.

<Individual> <Name></name> <instance-of></instance-of> <Slot-values> <Name>... </name> <Values>...</values> <value-type (or facet in **Table 3**)>...</value-type> </slot-values> </individual> At last, remember that XOL file must use </model> to note the ending.
