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. 

Create a git BitBucket/ Github repository from already locally existing project

• This post is originally targeted at BitBucket repositories, but the basic steps are common to Github too. 
• This is a simple issue but would get hours if followed the official Bitbucket.com instructions.  :P .So I am posting this.
• The case is that we have a project in our pc and it is almost completed (or partially done) and now we want to include it in a git repository and push it to a bitbucket repository. So note that we do not have still a BitBucket / Github repository for our project or a local git repo in our pc too. (but of course we have a bitbucket/github account :) )
• So, believe me.. follow these simple steps.

Pre-requisite: You should have installed git into your pc(PC=Personal Computer>>simply your computer).

1) Create a repository in Bitbucket.org / Github.com to contain our project.

• For this just click Repositories tab> Create New Repository (or simply click this link- https://bitbucket.org/repo/create)
• Simply fill the details you want and guess we filled the name as "TestingGitRepo"
• Click "Create Repository"

Now u have done with creating bitbucket repo.
(If u are dealing with Github, instead of Bitbucket, create the repository as the default way and remember not to tick "Initialize this repository with a README" ,because it will cause bit hard when doing the initial commit later.)

Just after creating the repo you will be redirected to a page as below.

Click "I have an existing project" and copy the command displayed below.

(It will be easier if you copy it here now)

The command we copied is,

git remote add origin https://Samitha@bitbucket.org/Samitha/testinggitrepo.git

(If u are using Github, a similar command with the starting part "git remote add origin"
will be displayed in the following page after the creation of repo, and just copy it)

2) Open command prompt in your PC and go inside to the directory where u want to be as a repository.

   For example if you go into the directory "G:\AndroidStudioWorkspace", the contents in that directory will be sent to the bitbucket/github repository you created.

3) Enter,

       git init

    This will initialize this directory as a git repo.
4) Now paste the command we copied and press enter.
  git remote add origin https://Samitha@bitbucket.org/Samitha/testinggitrepo.git

5) Enter,  
git add --all

This will add all the files and folders in this directory into the git repository.

6)Now you have to make the initial commit. So enter,  
git commit -m "Initial Commit"

At here sometimes there will give an error message as follows if you are using git in your PC fresh and so have not configured your Bit Bucket account with the git.

If you get this error just do what has been asked to do.
Enter,
git config --global user.email "rmschathuranga@gmail.com"
git config --global user.name "Samitha"

Note that you have to use your email address and bit bucket user name instead of 
rmschathuranga@gmail.com and Samitha (which are MINE)..!!!
7) Now enter,  
git push -u origin master
Enter the password of your bitbucket/github account when prompted.So then all the files and folders in your local repo will be pushed (uploaded) to the bitbucket repo, creating a new branch with the name "master". You will see messages as below,

     And that's all. You have done it.
Go check in the bitbucket/github repository you created. Your project has been successfully uploaded into the bitbucket repo. And the repository is successfully created. 

Important Notes:

• Whenever you make changes in your local project files, and want to push the changes into the remote bitbucket/github repository just follow above 5,6,7 steps.
• Note that if a directory is empty, that will not be added to git (to the remote repo too).
• If you want deeper clarification, anyway Git doesn't ignore empty directories. It typically ignores all directories. In Git, directories exist only implicitly, through their contents. Empty directories have no contents, therefore they don't exist in git repositories.

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For extra knowledge
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git add command

For extra knowledge I would like to go deep on git add command.

git add has number of options for various requirements. Following tables (extracted from http://certificationquestions.com/version-control-system/git/difference-git-add-git-add-git-add-u/ ) clearly shows the difference between them. Note that,
git add -A  = git add --all 

You can find your git version by git version command

For git versions 1.x

For git version 2.x

So my recommendation is to use git add --all which is similar to git add -A as it is the most common and general requirement. 

And here I am highlighting the difference between,

           git add . and git add --all 

in git version 1.x which most of us use now. It is that git add --all stages all the changes to the repository, while git add . do not stage deleted files. It means that if u had deleted a file in your local repository and u want it to be deleted from the remote repository too, u should do git add --all But git add . would not remove that file from the remote repository.

Comments a and suggestions are highly appreciated if u found this post useful..!!! :-)