diff --git a/classes/context/Context.class.php b/classes/context/Context.class.php
index 8b0e70682..aa591f72e 100644
--- a/classes/context/Context.class.php
+++ b/classes/context/Context.class.php
@@ -362,7 +362,8 @@ class Context {
 	function checkSSO() {
 		// pass if it's not GET request or XE is not yet installed
 		if($this->db_info->use_sso != 'Y' || isCrawler()) return true;
-		if(Context::getRequestMethod()!='GET' || !Context::isInstalled() || in_array(Context::get('act'),array('rss','atom'))) return true;
+		$checkActList = array('rss'=>1, 'atom'=>1);
+		if(Context::getRequestMethod()!='GET' || !Context::isInstalled() || isset($checkActList[Context::get('act')])) return true;
 
 		// pass if default URL is not set
 		$default_url = trim($this->db_info->default_url);
@@ -630,8 +631,8 @@ class Context {
 	function setResponseMethod($method='HTML') {
 		is_a($this,'Context')?$self=&$this:$self=&Context::getInstance();
 
-		$methods = array('HTML','XMLRPC','JSON');
-		$self->response_method = in_array($method, $methods)?$method:$methods[0];
+		$methods = array('HTML'=>1, 'XMLRPC'=>1, 'JSON'=>1);
+		$self->response_method = isset($methods[$method]) ? $method : 'HTML';
 	}
 
 	/*
@@ -644,9 +645,9 @@ class Context {
 		if($self->response_method) return $self->response_method;
 
 		$method  = $self->getRequestMethod();
-		$methods = array('HTML','XMLRPC','JSON');
+		$methods = array('HTML'=>1, 'XMLRPC'=>1, 'JSON'=>1);
 
-		return in_array($method, $methods)?$method:$methods[0];
+		return isset($methods[$method]) ? $method : 'HTML';
 	}
 
 	/**
@@ -891,7 +892,8 @@ class Context {
 				$key = $get_vars['key'];
 				$srl = $get_vars['document_srl'];
 
-				$is_feed = in_array($act, array('rss', 'atom', 'api'));
+				$tmpArray = array('rss'=>1, 'atom'=>1, 'api'=>1);
+				$is_feed = isset($tmpArray[$act]);
 
 				$target_map = array(
 					'vid'=>$vid,
diff --git a/classes/db/DB.class.php b/classes/db/DB.class.php
index 48fe547f2..d339947a1 100644
--- a/classes/db/DB.class.php
+++ b/classes/db/DB.class.php
@@ -422,7 +422,8 @@
 					$id = $id_args[1];
 				} elseif(count($id_args) == 3) {
 					$target = $id_args[0];
-					if(!in_array($target, array('addons','widgets'))){
+					$typeList = array('addons'=>1, 'widgets'=>1);
+					if(!isset($typeList[$target])){
 						$this->actDBClassFinish();
 						return;
 					}
diff --git a/classes/db/DBMssql.class.php b/classes/db/DBMssql.class.php
index eb943cf9a..fe709a177 100644
--- a/classes/db/DBMssql.class.php
+++ b/classes/db/DBMssql.class.php
@@ -440,6 +440,7 @@
 		$unique_list = array();
 		$index_list = array();
 
+				$typeList = array('number'=>1, 'text'=>1);
                 foreach($columns as $column) {
                     $name = $column->attrs->name;
                     $type = $column->attrs->type;
@@ -454,7 +455,7 @@
                     $column_schema[] = sprintf('[%s] %s%s %s %s %s',
                     $name,
                     $this->column_type[$type],
-                    !in_array($type,array('number','text'))&&$size?'('.$size.')':'',
+                    !isset($typeList[$type])&&$size?'('.$size.')':'',
                     isset($default)?"default '".$default."'":'',
                     $notnull?'not null':'null',
                     $auto_increment?'identity(1,1)':''
diff --git a/classes/db/queryparts/condition/Condition.class.php b/classes/db/queryparts/condition/Condition.class.php
index 3f4c0a3a1..4e4a2c634 100644
--- a/classes/db/queryparts/condition/Condition.class.php
+++ b/classes/db/queryparts/condition/Condition.class.php
@@ -125,7 +125,11 @@
                                         // if variable is not set or is not string or number, return
                                         if(!isset($this->_value)) { $this->_show = false; break;}
                                         if($this->_value === '') { $this->_show = false; break; }
-                                        if(!in_array(gettype($this->_value), array('string', 'integer'))) {$this->_show = false; break; }
+										$tmpArray = array('string'=>1, 'integer'=>1);
+                                        if(!isset($tmpArray[gettype($this->_value)]))
+										{
+											$this->_show = false; break;
+										}
                                         break;
                                 case 'between' :
                                         if(!is_array($this->_value)) { $this->_show = false; break;}
diff --git a/classes/db/queryparts/condition/ConditionWithoutArgument.class.php b/classes/db/queryparts/condition/ConditionWithoutArgument.class.php
index f8e75eef4..688b3e2df 100644
--- a/classes/db/queryparts/condition/ConditionWithoutArgument.class.php
+++ b/classes/db/queryparts/condition/ConditionWithoutArgument.class.php
@@ -15,7 +15,8 @@
 		 */
 		function ConditionWithoutArgument($column_name, $argument, $operation, $pipe = ""){
                     parent::Condition($column_name, $argument, $operation, $pipe);
-                    if(in_array($operation, array('in', 'notin', 'not_in'))){
+					$tmpArray = array('in'=>1, 'notin'=>1, 'not_in'=>1);
+                    if(isset($tmpArray[$operation])){
                         if(is_array($argument)) $argument = implode($argument, ',');
                         $this->_value = '('. $argument .')';
                     }
diff --git a/classes/db/queryparts/table/MssqlTableWithHint.class.php b/classes/db/queryparts/table/MssqlTableWithHint.class.php
index 10f05035e..077456133 100644
--- a/classes/db/queryparts/table/MssqlTableWithHint.class.php
+++ b/classes/db/queryparts/table/MssqlTableWithHint.class.php
@@ -37,9 +37,10 @@
                     $result = parent::toString();
 
                     $index_hint_string = '';
+					$indexTypeList = array('USE'=>1, 'FORCE'=>1);
                     foreach($this->index_hints_list as $index_hint){
                         $index_hint_type = $index_hint->getIndexHintType();
-                        if(in_array($index_hint_type, array('USE', 'FORCE')))
+                        if(isset($indexTypeList[$index_hint_type]))
                                 $index_hint_string .= 'INDEX(' . $index_hint->getIndexName() . '), ';
                     }
                     if($index_hint_string != ''){
diff --git a/classes/frontendfile/FrontEndFileHandler.class.php b/classes/frontendfile/FrontEndFileHandler.class.php
index 636564062..6e68b47c2 100644
--- a/classes/frontendfile/FrontEndFileHandler.class.php
+++ b/classes/frontendfile/FrontEndFileHandler.class.php
@@ -109,8 +109,8 @@
 				$file->cdnVersion = $cdnVersion;
 			}
 
-			$availableExtension = array('css', 'js');
-			if (!in_array($file->fileExtension, $availableExtension)) return;
+			$availableExtension = array('css'=>1, 'js'=>1);
+			if (!isset($availableExtension[$file->fileExtension])) return;
 
 			$file->targetIe = $args[2];
 			$file->index = (int)$args[3];
diff --git a/classes/module/ModuleHandler.class.php b/classes/module/ModuleHandler.class.php
index b62ce9179..0bf64f526 100644
--- a/classes/module/ModuleHandler.class.php
+++ b/classes/module/ModuleHandler.class.php
@@ -430,7 +430,8 @@
 
             $procResult = $oModule->proc();
 
-			if(!$oModule->stop_proc && !in_array(Context::getRequestMethod(),array('XMLRPC','JSON')))
+			$methodList = array('XMLRPC'=>1, 'JSON'=>1);
+			if(!$oModule->stop_proc && !isset($methodList[Context::getRequestMethod()]))
 			{
 				$error = $oModule->getError();
 				$message = $oModule->getMessage();
@@ -522,7 +523,8 @@
             if(!$output->toBool()) $this->error = $output->getMessage();
 
             // Use message view object, if HTML call
-            if(!in_array(Context::getRequestMethod(),array('XMLRPC','JSON'))) {
+			$methodList = array('XMLRPC'=>1, 'JSON'=>1);
+            if(!isset($methodList[Context::getRequestMethod()])) {
 
 				if($_SESSION['XE_VALIDATOR_RETURN_URL'])
 				{
@@ -634,8 +636,8 @@
 			$kind = strtolower($kind);
 			$type = strtolower($type);
 
-			$kinds = explode(' ', 'svc admin');
-			if(!in_array($kind, $kinds)) $kind = $kinds[0];
+			$kinds = array('svc'=>1, 'admin'=>1);
+			if(!isset($kinds[$kind])) $kind = 'svc';
 
 			$key = $module.'.'.($kind!='admin'?'':'admin').'.'.$type;
 
diff --git a/classes/module/ModuleObject.class.php b/classes/module/ModuleObject.class.php
index 0b4104752..30949b318 100644
--- a/classes/module/ModuleObject.class.php
+++ b/classes/module/ModuleObject.class.php
@@ -104,7 +104,8 @@
 		 **/
 		function getMessageType(){
 			$type = $this->get('message_type');
-			if (!in_array($type, array('error', 'info', 'update'))){
+			$typeList = array('error'=>1, 'info'=>1, 'update'=>1);
+			if (!isset($typeList[$type])){
 				$type = $this->getError()?'error':'info';
 			}
 			return $type;
diff --git a/classes/template/TemplateHandler.class.php b/classes/template/TemplateHandler.class.php
index 372f54e2a..edcf8ef70 100644
--- a/classes/template/TemplateHandler.class.php
+++ b/classes/template/TemplateHandler.class.php
@@ -351,7 +351,7 @@ class TemplateHandler {
 		$nodes = preg_split($split_regex, $buff, -1, PREG_SPLIT_DELIM_CAPTURE);
 
 		// list of self closing tags
-		$self_closing = explode(',', 'area,base,basefont,br,hr,input,img,link,meta,param,frame,col');
+		$self_closing = array('area'=>1,'base'=>1,'basefont'=>1,'br'=>1,'hr'=>1,'input'=>1,'img'=>1,'link'=>1,'meta'=>1,'param'=>1,'frame'=>1,'col'=>1);
 
 		for($idx=1,$node_len=count($nodes); $idx < $node_len; $idx+=2) {
 			if(!($node=$nodes[$idx])) continue;
@@ -392,7 +392,7 @@ class TemplateHandler {
 
 				// find closing tag
 				$close_php = '<?php '.str_repeat('}', $closing).' ?>';
-				if($node{1} == '!' || substr($node,-2,1) == '/' || in_array($tag, $self_closing)) { //  self closing tag
+				if($node{1} == '!' || substr($node,-2,1) == '/' || isset($self_closing[$tag])) { //  self closing tag
 					$nodes[$idx+1] = $close_php.$nodes[$idx+1];
 				} else {
 					$depth = 1;
diff --git a/classes/xml/XmlParser.class.php b/classes/xml/XmlParser.class.php
index 9e3a6cbbe..366d40ba3 100644
--- a/classes/xml/XmlParser.class.php
+++ b/classes/xml/XmlParser.class.php
@@ -87,9 +87,10 @@
 
             // extracts the supported lanuage when xml:lang is used
             if(count($matches[1]) && $supported_lang = array_unique($matches[1])) {
+				$tmpLangList = array_flip($supported_lang);
                 // if lang of the first log-in user doesn't exist, apply en by default if exists. Otherwise apply the first lang.
-                if(!in_array($this->lang, $supported_lang)) {
-                    if(in_array('en', $supported_lang)) {
+                if(!isset($tmpLangList[$this->lang])) {
+                    if(isset($tmpLangList['en'])) {
                         $this->lang = 'en';
                     } else {
                         $this->lang = array_shift($supported_lang);
diff --git a/classes/xml/XmlQueryParser.class.php b/classes/xml/XmlQueryParser.class.php
index 48aea3ff5..0bc5c8a0f 100644
--- a/classes/xml/XmlQueryParser.class.php
+++ b/classes/xml/XmlQueryParser.class.php
@@ -35,7 +35,8 @@
                 $id = $id_args[1];
             } elseif(count($id_args)==3) {
                 $target = $id_args[0];
-                if(!in_array($target, array('modules','addons','widgets'))) return;
+				$typeList = array('modules'=>1, 'addons'=>1, 'widgets'=>1);
+                if(!isset($typeList[$target])) return;
                 $module = $id_args[1];
                 $id = $id_args[2];
             }
@@ -52,6 +53,7 @@
 
             if(!$tables) return;
             if(!is_array($tables)) $tables = array($tables);
+			$joinList = array('left join'=>1, 'left outer join'=>1, 'right join'=>1, 'right outer join'=>1);
             foreach($tables as $key => $val) {
 
                 // 테이블과 alias의 이름을 구함
@@ -61,7 +63,7 @@
 
                 $output->tables[$alias] = $table_name;
 
-                if(in_array($val->attrs->type,array('left join','left outer join','right join','right outer join')) && count($val->conditions)){
+                if(isset($joinList[$val->attrs->type]) && count($val->conditions)){
                     $output->left_tables[$alias] =  $val->attrs->type;
                     $left_conditions[$alias] = $val->conditions;
                 }
diff --git a/classes/xml/xmlquery/QueryParser.class.php b/classes/xml/xmlquery/QueryParser.class.php
index 056b123ec..ab1366a37 100644
--- a/classes/xml/xmlquery/QueryParser.class.php
+++ b/classes/xml/xmlquery/QueryParser.class.php
@@ -40,7 +40,8 @@
                 $id = $id_args[1];
             } elseif (count($id_args) == 3) {
                 $target = $id_args[0];
-                if (!in_array($target, array('modules', 'addons', 'widgets')))
+				$targetList = array('modules'=>1, 'addons'=>1, 'widgets'=>1);
+                if (!isset($targetList[$target]))
                     return;
                 $module = $id_args[1];
                 $id = $id_args[2];
diff --git a/classes/xml/xmlquery/argument/Argument.class.php b/classes/xml/xmlquery/argument/Argument.class.php
index 146f097a7..7136f7d22 100644
--- a/classes/xml/xmlquery/argument/Argument.class.php
+++ b/classes/xml/xmlquery/argument/Argument.class.php
@@ -130,7 +130,8 @@ class Argument {
 		if (!isset($value))
 			return null;
 
-		if (in_array($column_type, array('date', 'varchar', 'char', 'text', 'bigtext'))) {
+		$columnTypeList = array('date'=>1, 'varchar'=>1, 'char'=>1, 'text'=>1, 'bigtext'=>1);
+		if (isset($columnTypeList[$column_type])) {
 			if (!is_array($value))
 				$value = $this->_escapeStringValue($value);
 			else {
diff --git a/classes/xml/xmlquery/argument/ConditionArgument.class.php b/classes/xml/xmlquery/argument/ConditionArgument.class.php
index ce7f17934..e5471a79c 100644
--- a/classes/xml/xmlquery/argument/ConditionArgument.class.php
+++ b/classes/xml/xmlquery/argument/ConditionArgument.class.php
@@ -21,7 +21,8 @@
 		 * @return void
 		 */
 		function ConditionArgument($name, $value, $operation){
-			if(isset($value) && in_array($operation, array('in', 'notin','not_in', 'between')) && !is_array($value) && $value != ''){
+			$operationList = array('in'=>1, 'notin'=>1, 'not_in'=>1, 'between'=>1);
+			if(isset($value) && isset($operationList[$operation]) && !is_array($value) && $value != ''){
 				$value = str_replace(' ', '', $value);
 				$value = str_replace('\'', '', $value);
 				$value = explode(',', $value);
diff --git a/classes/xml/xmlquery/tags/condition/ConditionTag.class.php b/classes/xml/xmlquery/tags/condition/ConditionTag.class.php
index ea82fdc25..dbb37c82a 100644
--- a/classes/xml/xmlquery/tags/condition/ConditionTag.class.php
+++ b/classes/xml/xmlquery/tags/condition/ConditionTag.class.php
@@ -70,7 +70,8 @@
 			}
 			else {
                             if(isset($condition->attrs->default)){
-                              if(in_array($this->operation, array('in', 'between', 'not in'))){
+								$operationList = array('in'=>1, 'between'=>1, 'not in'=>1);
+                              if(isset($operationList[$this->operation])){
                                     $default_value = $condition->attrs->default;
                                     if(strpos($default_value, "'") !== false)
                                         $default_value = "\"" . $default_value . "\"";
diff --git a/classes/xml/xmlquery/tags/navigation/IndexTag.class.php b/classes/xml/xmlquery/tags/navigation/IndexTag.class.php
index d51505fd9..3f3a5bc7c 100644
--- a/classes/xml/xmlquery/tags/navigation/IndexTag.class.php
+++ b/classes/xml/xmlquery/tags/navigation/IndexTag.class.php
@@ -49,7 +49,8 @@
 
                         // Sort order - asc / desc
 			$this->sort_order = $index->attrs->order;
-			if(!in_array($this->sort_order, array("asc", "desc"))){
+			$sortList = array('asc'=>1, 'desc'=>1);
+			if(!isset($sortList[$this->sort_order])){
 				$arg = new Xml_Node_();
 				$arg->attrs = new Xml_Node_();
 				$arg->attrs->var = $this->sort_order;
diff --git a/classes/xml/xmlquery/tags/table/TableTag.class.php b/classes/xml/xmlquery/tags/table/TableTag.class.php
index 80fffac1f..1c4d066af 100644
--- a/classes/xml/xmlquery/tags/table/TableTag.class.php
+++ b/classes/xml/xmlquery/tags/table/TableTag.class.php
@@ -75,7 +75,8 @@
 		}
 		
 		function isJoinTable(){
-			if(in_array($this->join_type,array('left join','left outer join','right join','right outer join')) 
+			$joinList = array('left join'=>1, 'left outer join'=>1, 'right join'=>1, 'right outer join'=>1);
+			if(isset($joinList[$this->join_type])
 				&& count($this->conditions)) return true;
 			return false;
 		}