Semantic web - programmer's approach

Back on to my Macro Blog :)

ndotnanda — Wed, 17 Feb 2010 12:49:23 +0000

After spending a long time with social networking sites facebook, Google, twitter .. I am back on with my blog to write my thoughts . Lets expect more on semantic web, Social media & personal .

RDF- Crack (RDFa, triples,FOAF) ( part 2 )

ndotnanda — Tue, 01 Jul 2008 21:02:03 +0000

RDF is a way of presenting knowledge, relationship or a thing in the format of triples. For everything in the web will be represented as a triples format. As we know about grammer we read it in our child hood, like every basic sentence is represented as format of triples. That means subject, predicate & objects.

FOAF:

FOAF is the vocabulary to represent RDF the objects & relationship between them. FOAF is a way of describing a person / company. FOAF is Friend of A friend using RDF to represent its data. It will describe a person in the following way.

nandakumar -> is -> http://www.desiji.com/ndotnanda


 
   Nandakumar
   
 


N3 Notation & triples:
A syntax to represent RDF.
@prefix pref .
<#nandakumar><#ndot>

RDFa:
RDFa is way to integrate RDF into XHTML pages. It reduces the lot of work & difficulties for
normal people those who want to represent their blog / personal data into semantic web. RDFa helps
them to represent their information to semantic web with XTHML. we can take an small example about
how we can represent a data with RDFa,

Here we are going to explain a FOAF integration into XHTML page.

Triples:
Nandakumar knows Preethi

RDFa:



Nandakumar Somasundaram


Triple : Nandakumar -> Name -> Nandakumar Somasundaram

RDFa : example 2


Nandakumar Somasundaram


Preethi


Nandakumar is classmate of preethi



RDF – Crack ( part I )
ndotnanda — Sun, 29 Jun 2008 09:41:21 +0000

Resource Description Framework – is the w3c standard, language to describe information in (semantic) web.Is it a new language / structure that we have to read? Absolutely not. It’s an XML /N3 format of representing the data.

RDF is about describing  relationship between web resources ex. URLs. It will be represented as triples format.

Basic Structure:
http://www.desiji.com/ndotnanda has a profile whose value is Nandakumar Somasundaram
It is in triples format.

the subject is the      URL http://www.desiji.com/ndotnanda
the predicate is      the word “profile”
the object is the      phrase “Nandakumar Somasundaram”

Normally RDF data is represented as triples Triples are a sequence of (subject, predicate, object) terms. N-Triples is a line-based, plain text format for encoding an RDF graph.

There are few ways to define RDF data.

RDF/XML      ( for machine reading ) rdf/xml
RDF/Notation3(N3)      ( for human reading ) MIME type : text/rdf+n3
Turtle is a subset of N3 to represent the RDF      data


RDF/XML representation: RDF defines a specific XML markup language, referred to as RDF/XML, for use in representing RDF information, and for exchanging it between machines.
         xmlns:dc="http://purl.org/dc/elements/1.1/">
  
    Jan Grant
    Dave Beckett
    
      
        World Wide Web Consortium
        
      
    
  






N3 (Notation 3)
Notation 3 is a way of presenting semantic data in human understandable format. N3 representation of above RDF graph.
   .

  "August 16, 1999" .

  "en" .
 N3 Subsets

More Information:

RDF Schema – http://www.w3.org/TR/rdf-schema/
RDF Syntax – http://www.w3.org/TR/REC-rdf-syntax/#basicconcepts
RDF – http://vanirsystems.com/danielsblog/2008/04/23/rdf-simpler-if-you-look-at-it-in-a-different-way/
http://infolab.stanford.edu/~melnik/rdf/syntax.html
http://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax


Upcoming “RDF- Crack” versions will have lot of examples, details.


         


Open Calais API & examples – PHP
ndotnanda — Fri, 27 Jun 2008 08:58:42 +0000
Open Calais is a rapidly growing toolkit of capabilities that allow you to readily incorporate state-of-the-art semantic functionality within your blog & provide more or less same functionality as what zemanta guys do.
Open calais use NLP to manipulate user’s queries. They are giving API access to multiple languages. Here i can explain the samples with php.
Live URL : http://livebillion.com/calais/
index.php

URL :  

octest.php
$apikey = “XXXXXXXXXX”;
$oc = new OpenCalais($apikey);
if(isset($_REQUEST["url"])){

$content = file_get_contents($_REQUEST["url"]);

}
//echo $content;
$entities = $oc->getEntities($content);
foreach ($entities as $type => $values) {
echo “” . $type . “”;

echo “
”;
foreach ($values as $entity) {

echo “
” . $entity . “
”;

}
echo “
”;
}
opencalais.php
http://www.dangrossman.info/open-calais-tagsopen-calais-tags

All the best  


         


Zemanta API & examples – over view with PHP
ndotnanda — Fri, 27 Jun 2008 08:45:51 +0000
Zemanta provides live suggesions when you start writing blogs.  Zemanta also a browser based plugin gives you suggestions based on your text that you typing, image, url’s & more.
What is the purpose of using Zemanta ?
You can get relevant tags what you have typed.
NLP – Natural Language processing, it analyze your input text with lexical analyzer & find out the tags(/objects/names)
Based on that tags, it lists the number of URL’s/ images found related to those tags.
Input  : “text”
Output : Related URLs, Tags & images
Sample Code how it works,
Contact Zemanta & get API from them.
Live Testing URL :  http://livebillion.com/calais/test_zemanta.php
test_zemanta.php
——–









Testing Zemanta API
Text: 




 ——— Or ————–
URL: 




 



dozemanta.php
$url = ‘http://api.zemanta.com/services/rest/0.0/’; //Should be in a conffile

$format = ‘xml’; // May depend of your application context

$text = $_REQUEST["text"];

if($_REQUEST["url"]!=”"){

$text = strip_tags(file_get_contents($_REQUEST["url"]));

}
$key = “YOUR_API_KEY”; //Should be in a conf file

$method = “zemanta.suggest”; // May depend of your application context
$args = array(

‘method’=> $method,

‘api_key’=> $key,

‘text’=> $text,

‘format’=> $format

);
$data = “Here we build the data we want to POST to Zementa”;

foreach($args as $key=>$value)

{

$data .= ($data != “”)?”&”:”";

$data .= urlencode($key).”=”.urlencode($value);

}
/* Initialisation of curl */

$ch = curl_init();

/* Setup of the url*/

curl_setopt($ch, CURLOPT_URL, $url);

/* We want a post request */

curl_setopt($ch, CURLOPT_POST, 1);

/* Here we give to curl the data we want to send to Zementa*/

curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

/* We setup the response method of curl */

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

/* Execute curl and fetch the result */

$response = curl_exec ($ch);

/* Close curl connection */

curl_close ($ch);

//echo $response;
$xmlArray = xml2array($response); // XML2ARRAY is a function to covert xml to array
// Get the top array
$content = $xmlArray["rsp"];
// Related Articles
foreach($content["articles"] as $articles){

$i = 0;

echo ‘
’;

foreach($articles as $article){

//echo $i;

//echo $article["url"]["value"];

echo ‘’;

$i++;

}

//print_r($articles[0]["url"]["value"]);

echo ‘Related Articles:
’.$article["title"]["value"].’
’;

}
// Related Keywords
foreach($content["keywords"] as $keywords){

//print_r($markup);

$i = 0;

echo ‘
Keywords:
’;

foreach($keywords as $keyword){

//echo $i;

//echo $article["url"]["value"];

echo ‘’.$keyword["name"]["value"].’   ’;

$i++;

}

//print_r($articles[0]["url"]["value"]);

echo ‘
’;

}
// Related Images
foreach($content["images"] as $images){

//print_r($markup);

$i = 0;

echo ‘
’;

foreach($images as $image){

//echo $i;

//echo $article["url"]["value"];

echo ‘’;

$i++;

}

//print_r($articles[0]["url"]["value"]);

echo ‘Images:
’.$image["description"]["value"].’
’;

}


         


Buzzwords of semantic web
ndotnanda — Thu, 26 Jun 2008 12:28:02 +0000
Since 2000, people are talking much about semantic web, web 2, web 3 .. what are the buzzwords behind the semantic web ?
semantic web – a meaning of web by the web itself. Making the web understandable by machines.
RDF -  Resource Description Framework – W3C Standards to descripe anything in semantic web – it is an XML - RDF is a directed, labeled graph data format for representing information      in the Web
FOAF - Friend Of A Friend – W3C standards to describe people & networks, the links between them and the things they create and do
SIOC - Semantically interconnected Online Communities -   a Semantic Web ontology for representing rich data from the Social Web in RDF
OWL - Web Ontology Language (Ontology – representation of a set of concepts within a domain and the relationships between them) – it is a family of ontologies to describe semantic web – OWL ontologies are most commonly serialized using RDF/XML syntax
SPARQL - SPARQL Protocol and RDF Query Language , is an RDF query language
Linked Open Data – is a community lead effort to create openly accessible, and interlinked, RDF Data on the Web
APML - allows users to share their own personal Attention Profile
Attention Profile – A profile that have build with a combination of your Semantic data
Open ID - open decentralized ID system that provides single access to the web
OAuth - OAuth is a simple way to publish and interact with protected data. It’s also a safer and more secure way for people to give you access.
Single Sign ON (SS0) -  a secured authentication for over the web.
Data Portability – a mixing of open standars inclucing RDF,OPML,Micro formats,APML,OpenID ..
Microformats - Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards
NLP – Natural Language Processing -  handling human languages
Some Buzz Applications :
know3 – http://www.know3.com
Twine – http://www.twine.com
powerset – http://www.powerset.com
Yahoo Search Monkey
DBpedia
freebase
radarnetworks
trueknowledge.com
talis platform
opencalais
Data Portability.org
zemanta.com
Add more applications & buzzwords & comments to make this a library for beginners .. thanks for reading this..