predicting whether a given text shows a
<font style='background-color: #90EE90'>positive</font>,
<font style='background-color: #FFA07A'>negative</font> or
<font style='background-color: #DCDCDC'>neutral</font>
sentiment/feeling.</p>
<p>In order to produce this system, a Text Classification technique
has to be adapted to a given application domain. In this demo, the
<a href='http://nlp.cs.swarthmore.edu/semeval/'>SemEval-2007 dataset</a>
is of use for training the classifier, and the learnt model is then
applied to processing similar world news headlines from
The Washington Post:</p>
<?php
// Prepare classifier
$classifier = new MultinomialNaiveBayes();
$classifier->setDatabase("semeval07");
// Prepare data
$feeder = new FeedRSS();
$aFeeds = $feeder->getFood("http://feeds.washingtonpost.com/rss/world");
foreach ($aFeeds as $feed) {
$lab = $classifier->classify($feed["title"]);
if ($lab == "NEG") {
echo "<p class='neg'>";
} elseif ($lab == "NEU") {
echo "<p class='neu'>";
} else {
echo "<p class='pos'>";
}
echo "• " . $feed["title"] . " - <a href='" . $feed["link"] . "'>Read more</a></p>";
}
</font>
</p>
<hr>
<?php
if (isset($_POST["gotrain"])) {
if ($_POST["gotrain"] == "true") {
if ($_FILES["datafile"]["error"] > 0 || empty($_POST["newdbname"])) {
echo "Error!!! Missing parameters!\n";
} else {
try {
echo "<p>Loading dataset... ";
$dataset = new Dataset();
list($text, $labs) = $dataset->getFood($_FILES["datafile"]["tmp_name"]);
echo "OK</p>";
echo "<p>Training model... ";
$classifier = new MultinomialNaiveBayes();
$classifier->train($text, $labs);
echo "OK</p>";
echo "<p>Saving parameters... ";
$classifier->setDatabase($_POST["newdbname"]);
$classifier->save();
echo "OK</p>";
echo "<p><b>Training process completed " . "successfully!</b></p>";
} catch (Exception $e) {
echo "Caught exception: " . $e->getMessage() . "\n";
}
}
}
}
?>
</body>
} else {
// create new user
$db->query("INSERT INTO Users VALUES ( '{$callerIP}', 1 );");
}
}
// Check length of query
if ($granted) {
$data = RestUtils::processRequest();
if ($premium || strlen($data->getTextToProc()) > 0 && strlen($data->getTextToProc()) < 2000) {
switch ($data->getMethod()) {
case 'post':
// right method
$serv = $data->getService();
if ($serv == 'sentiment_news') {
$tex = $data->getTextToProc();
$classifier = new MultinomialNaiveBayes();
$classifier->setDatabase("semeval07");
$pNEG = $classifier->likelihood($tex, "NEG");
$pNEU = $classifier->likelihood($tex, "NEU");
$pPOS = $classifier->likelihood($tex, "POS");
// Too long, force to neutral, sentiment wash
if ($pNEG == false) {
$pNEU = 1;
} else {
$pTotal = $pNEG + $pNEU + $pPOS;
$pNEG = $pNEG / $pTotal;
$pNEU = $pNEU / $pTotal;
$pPOS = $pPOS / $pTotal;
}
// No need to hit the DB again
$lab = "NEG";
include dirname(__FILE__) . "/../core/classification/MultinomialNaiveBayes.php";
include dirname(__FILE__) . "/../core/util/feeding/FeedRSS.php";
include dirname(__FILE__) . "/pagemaker.php";
putHeader("Text Categorisation and Topic/Domain Identification");
?>
<p>Identifies the semantic field of a given text and relates it
to its corresponding topic or domain.</p>
<p>In order to produce this system, a Text Classification technique
has to be adapted to a given set of application domains. In this demo,
the <a href='http://kdd.ics.uci.edu/databases/reuters_transcribed/reuters_transcribed.html'>Reuters Transcribed Subset</a>
is of use for training the classifier, and the learnt model is then
applied to predicting the topic of the most read articles from Reuters:</p>
<?php
// Prepare classifier
$classifier = new MultinomialNaiveBayes();
$classifier->setDatabase("ReutersTranscribedSubset");
// Prepare data
$feeder = new FeedRSS();
$aFeeds = $feeder->getFood("http://feeds.reuters.com/reuters/MostRead?format=xml");
foreach ($aFeeds as $feed) {
$lab = $classifier->classify($feed["title"]);
echo "<p><font color='#808080'>Topic: " . $lab . "</font><br />";
echo " <b>" . $feed["title"] . "</b>" . " - <a href='" . $feed["link"] . "'>Read more</a><br /> " . preg_replace("/<.+>/", "", $feed["desc"]) . "</p>";
}
?>
<?php
putFooter();