Wednesday, July 8, 2015

More on semantic wiki...


              In my previous post with the title "Semantics into wiki", I discussed the major concepts behind the "Semantic wiki". Today I am going to dive bit deeper in it.
              Semantic wiki has the following basic features. One is that it is still a wiki, with regular wiki features such as  Category/Tags, Namespaces, Title, Versioning, etc... The articles have typed Content (built-ins + user created, e.g. categories) and types can be of Page/Card, Date, Number, URL/Email, String, etc…. The articles are connected with typed Links (e.g. properties) such as “capital_of”, “contains”, “born_in”… Some semantic wikis has Querying Interface Support too.

            Annotations are used in semantic wiki to make information more explicit, which is actually the most important of semantic wikis. These annotations have specific markup syntax. This markup syntax is used to edit or add articles into the wiki. These syntaxes might differ in different semantic wikis and in my this article I’m focusing on semantic media wiki. Categories, typed links and attributes are some of these annotations. “Category” is a one type which already exist in normal Wikipedia too.

Typed links are used instead of regular hyperlinks. In here an hyperlinks has a type. Links are arguably the most basic and also most relevant markup within a wiki. Their syntactic representation is ubiquitous in the source of any Wikipedia article. MediaWiki allows users to create new typed links freely as they prefer. Existing link types should be used wherever applicable, but a new type can also be created simply by using it in a link. A typed link can be a property of the current article and the syntax of inserting a property is,
[[Property::Value | Display]]

For example [[is capital of::England]]. Here the Property is “is capital” and it is linked to the article with the name “England” and that is the Value. And Display part is additional and there we can mention if something other than the value should be displayed on the article.   
 
Data values play a crucial role within an encyclopaedia, and machine access to this data yields numerous additional applications. These are called attributes and has the common syntax 
[[ attribute_name := value]]   
in the semantic media wiki. Eg: [[ population := 7,421,328 ]]

There can be an unit for an attribute value. Eg: [[area:=609 square miles]]. When many types of units are there for a same value, the system provides automatic conversion of a value to various other units. To allow users to declare the data type of an attribute, we introduce a new Wikipedia namespace “Attribute:” that contains articles on attributes. Within these articles, one can provide human-readable descriptions as in the case of relations and categories, but one can also add semantic information that specifies the data type. Using a relation with built-in semantic we can simply write,               [[hasType::Type:integer]] 
to denote that an attribute has this type.

            So as these, there is much more semantic wiki syntax types and it is important to learn all these, if we want to add a new article to a semantic wiki or edit currently available article.

Advanced Querying and Searching are some most important features in semantic wiki. There is a feature to search a property by its value in “Page property search”. There if we insert the property as “Located in” and value as “England” all the cities/regions located in England are listed via this advanced searching option. For advanced querying too there is a nice interface. For example if we give [[Category:City]][[located in::Germany]] into the Query field and  ?Population into the Additional data to display field a list of all the cities in Germany will be displayed with their population values. Following is the interface  available for querying.

The results of the query are displayed as follows.
 

Following is the basic architecture of semantic media wiki.

There are more applications of Semantic wiki such as,
      Desktop applications
o   AmaroK Media Player
o   Movie reviewer
o   Portals that aggregate data from various data sources (newsfeeds, blogs, online services)
      Over enhanced folksonomies
      Creating domain ontologies,
      Creation of multilingual dictionaries
      New re-search opportunities

As this way it is obvious that semantic wiki concept is going to be a very interesting and valuable concept to the whole world even though currently it is not much developed or popular. 


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