Help:GlossaryAtoO

From Wontology

Item Connection Subject Predicate Object

C D H I L M N O P R S T W X

Category

"Category" is one of the three types of items, along with Individual and Property. Category items should be used to represent groups of things, concepts, and (unsurprisingly) categories. Categories can contain both individuals and other categories.

Child

A "child" is an item that is in a parent-child relationship with another item, the "parent." Parent-child is a hierarchical relationship, and implies that the child is below or subsidiary-to its parent within the hierarchy. (If the hierarchy is a tree, the child is closer to the "leaves" than to the "root.") Being a child in relationship with one item does not prevent the child from having other relationships with other items, including also being a parent. While the parent-child relationship would obviously be used in a wontology for expressing geneology and family relationships between people, it is also commonly used to express more general hierarchical relations when other specific relationship types are not applicable.

Class

"Class" is a categorization mechanism for groups of items. Unlike type, which is an intrinsic part of an item, class is expressed in the system using a connection between the item and another item that represents the specific class to which it belongs, using the built-in is_instance_of property as the connection's predicate. Membership in a class is treated specially by the system (as opposed to any other relationship using a hierarchical property), and many of the system's behaviors are transitive across class membership. For example, a property can be applied to a class, and will automatically be treated by WontoMedia as if it were applied individually to each member of the class.

Connection

Connections are the fundamental representation of information in a wontology. An individual connection represents a factual statement, composed from the items in the wontology. Each connection refers to exactly three items in order: a subject, a predicate, and an object. The predicate (the verb, if the connection were a sentence) must be a Property-type item, and defines the type of relationship that exists between the subject and object items.

Controlled Vocabulary

A "controlled vocabulary" is a specific type of thesaurus used to specify the set of terms that will be used for characterizing a particular set of information resources. For example, consider a technical project, in which people produce many different project-related documents over time. The documents could include emails, proposals, specifications, reference material, etc. To make the documents more easily findable, they could be stored in some type of content-management system, which could assign a set of key words and phrases to each document. In this example, the controlled vocabulary is the allowed set of keywords with which documents can be marked. The advantage of not permitting any possible keyword to be used is that, when the documents are searched, it eliminates the possibility that some relevant documents will be missed because different people used different keywords for the same concept. The key difference between a controlled vocabulary and other types of thesauri is that a controlled vocabulary has preferred term relationships between its items. A preferred term is a term within the controlled vocabulary which is acceptable for use, while other terms are the not-to-be-used potential synonyms of the preferred terms. Controlled vocabularies can be used in several ways, including to filter keyword assignments to documents when originally created, to suggest a preferred term to a user if they supply another term, and to automatically map search queries to preferred terms. The items in a controlled vocabulary can also have all of the other relationships (synonym, more-specific, more-general, etc.) that would be found in a thesaurus.

Description

Every item in a wontology has an associated "Description" text field. The field is optional, but will almost always be used. For items that represent categories or individuals, the description should be a brief description of the thing/concept the item represents. For items that will be used to define a type of relationship (that is, referenced as the predicate item for a connection), the description should precisely define the meaning of the relationship that is intended when a connection is created using that item, and how that particular relationship item compares to others.

Hierarchy

A hierarchy is a common structure for organizing information, almost synonymous with a tree. A hierarchy typically starts with a single top (root, parent) item that has one or more subsidiary (contained, child) items. When a hierarchy is viewed as a tree, there is a single "root" and all items that don't have children are considered "leaves". Hierarchies are so common, it is typically easier to use examples than define them formally: organizaiton charts, category/sub-category schemes, file storage directory trees, and document outlines are all hierarchies.

Hierarchical Relationship

Within a wontology, a relationship is hierarchical if it implies that one of the items is closer to the "root" (top, base, start, origin, etc.) than the other. Any relationship may be hierarchical, regardless of the name used for it (the Name field of the Property-type item that is used to represent it). WontoMedia is told that a relationship is hierarchical by creating a connection using the sub_property_of type between the new property and another property that is already known to be hierarchical. (WontoMedia provides the built-in hierarchical_relationship property to provide the base of a chain of hierarchical-relationship properties.) Apart from any inferences that could be drawn from the hierarchical nature of a relationship, WontoMedia takes into account whether a relationship is hierarchical when creating pages that display the relationships between items. A peer relationship implies the opposite of a hierarchical relationship, and is also treated specially for display by WontoMedia. A property item cannot represent both a hierarchical and a peer relationship, but can represent (be sub_property_of) neither.

HTML

HTML, the Hyper Text Markup Language, is the fundamental language in which web pages are written. Web pages consist of content (usually text for people to read) grouped and classified by tags defined by HTML, and modern web pages frequently also contain blocks (delimited by an HTML tag) written in other web-defining languages as well.

Individual

"Individual" is one of the three types of items, along with Category and Property. Individual items should be used to represent specific, concrete things. Individuals can be in relationships where they "contain" other individuals, but they cannot contain categories. For example, if "Ford Model-T" were an individual, it could contain other individuals (component parts) like "Windshield" and "Tire" (which could, in turn, contain sub-components). The individual "Ford Model-T" may not contain the category "Automobiles". However, relationships are directional, and it would be completely sensible for the category "Automobiles" to contain "Ford Model-T".

Item

Along with connections, items are the fundamental informational elements in a wontology. Items represent the things that a wontology describes, and connections represent the relationships between those things. An item can represent anything about which a wontology will contain information. Items can represent abstract concepts ("red") or groupings ("automobiles"), types of physical things ("car"), individual physical things (myself, my particular car), etc. Basically, anything that could be construed to be a noun in natural language grammar is a candidate for being an item. WontoMedia has three specialized types of items (Category, Individual, and Property) to distinguish the different types of things that the items represent. In addition to its type, each item in a wontology has a Title, a Name, and an optional Description. These provide human-readable information and collectively identify what the item represents. All other "facts" about an item are represented in a wontology by connections connecting the item and other items. Each connection makes a statement about the relationship between the items involved.

List

A list is a very simple structure for organizing information: simply the list itself, and one or more items that it contains. If a list's items themselves have sub-items, then the "list" is actually a more complicated structure like a hierarchy. Many times in informal use "the list itself" is not identified except implicitly by the list items, or perhaps with a title. In a wontology, there must be a specific item to represent the list as a whole, and each item is made part of the list by creating a separate connection like "thisList contains thatItem".

Microformat

"Microformats" are a standardized set of conventions for embedding machine-parseable information in HTML web pages primarily intended to be human readable. There are a variety of different standards, unified by a common methodology, under the umbrella of microformats (see microformats.org). Each microformat defines a domain-specific data schema and specific HTML markup practices for encoding that schema within a web page. For more information, see Microformats: Empowering Your Markup for Web 2.0

Name

In the context of a wontology, a "Name" is a data field associated with an item. All items have a Name, which should be a unique, meaningful (to a person) identifier for that item. Items also have a required data field called "Title", which serves a purpose similar to Name. Titles may be longer than names, and can use a broader set of text characters. In WontoMedia a Name may be no more than 80 characters, must start with an (English) alphabetic character, and can contain only letters, numbers, the dash ("-") and the underscore ("_"). When WontoMedia creates a web address (a URL) to refer to an item, it uses the item's Name (this is the reason the set of characters is restricted). The Name is also used as the unique identifier for the item when export files are created or when ontology information is exchanged over the Internet between a WontoMedia site and other systems. When formatting a page that refers to an item, WontoMedia will show the item's Title, the item's Name, or both, depending on the amount of space available. An item's Title should be an accurate enough reference to what the item represents that anyone who's read the item's Description will know exactly what the item means, and most other people will have a good guess. An item's Name should be a good reminder of the item's Title and of what the item represents, but it is more important that it be relatively short and unique within its ontology.

Object

An "object," in the context of an individual connection in a wontology, is the third item that the connection references. A connection's object item is named that way by analogy, from viewing a connection as a sentence making a statement about the relationship between items. Thus, a connection is composed "subject predicate object" like the sentence fragment "ball is red". Virtually all items will be both subjects and objects of different connections. However, connections are directional, and just as "red is ball" isn't a very sensible statement in English, reversing the subject and object in a connection will usually make a very different, and likely invalid, statement. Connections can also be viewed as arrows from one item (the subject) to another (the object) in a graph, in which case the object is the item that the arrow points to.

Ontology

While it has a very different definition in philosophy, in information science an ontology is a structured representation of information about a subject area. There are a range of named structures for organizing information, these range from the very simplest that everyone is familiar with like lists, trees (hierarchies) and tables, to more specialized forms like controlled vocabularies and thesauri, up to ontologies. An ontology is the most general and expressive approach to categorizing and classifying information, in which the assumptions and restrictions of the other forms are relaxed, though they may be re-enforced in subsets of an ontology by inclusion of the appropriate relationships. For more information about different information organization schemes, including ontologies, see Information Architecture for the World Wide Web: Designing Large-Scale Web Sites, especially the chapter "Thesauri, Controlled Vocabularies, and Metadata". For a more hands-on introduction to ontologies and their potential uses, consider Programming the Semantic Web.

OWL

"OWL" is short for the World Wide Web Consortium's "Web Ontology Language" standard. This standard alows for the exchange of ontologies between different systems on the Internet. The WontoMedia web application will be capable of working with any ontology that can be expressed in OWL, although the current version has some limitations in the types of relationships it can express, the OWL semantics that it interprets and enforces, and its ability to import and export ontologies in XML, RDF, and OWL. We have a number of tutorials introducing how different types of information can be represented using the items and connections from which an ontology is built. For additional information about the history and creation of ontologies, consider "Semantic Web for the Working Ontologist: Effective Modeling in RDFS and OWL" or "Owl: Representing Information Using the Web Ontology Language"

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