diff --git a/src/sammo/Session.php b/src/sammo/Session.php
index a9c73f5c..82084712 100644
--- a/src/sammo/Session.php
+++ b/src/sammo/Session.php
@@ -44,7 +44,7 @@ class Session {
         ini_set('session.use_only_cookies', false);
         ini_set('session.use_cookies', false);
         ini_set('session.use_trans_sid', false);
-        ini_set('session.cache_limiter', null);
+        ini_set('session.cache_limiter', "none");
         session_start($this->sessionID); // second session_start
         $this->writeClosed = false;
         return $this;
@@ -113,7 +113,7 @@ class Session {
     }
 
     public function __set(string $name, $value){
-        if(key_exists($key, $this->PROTECED_NAMES)){
+        if(key_exists($name, $this->PROTECED_NAMES)){
             trigger_error("{$name}은 외부에서 쓰기 금지된 Session 변수입니다.", E_USER_NOTICE);
             return;
         }
diff --git a/src/sammo/StringUtil.php b/src/sammo/StringUtil.php
index 011a1d26..2c4e74de 100644
--- a/src/sammo/StringUtil.php
+++ b/src/sammo/StringUtil.php
@@ -163,6 +163,7 @@ class StringUtil {
         $size = strlen($str);
 
         $count = ($maxsize - $size) / 2;
+        $string = '';
 
         for($i=0; $i < $count; $i++) {
             $string = $string.$ch;
diff --git a/src/sammo/Util.php b/src/sammo/Util.php
index 99c50867..88d46ecc 100644
--- a/src/sammo/Util.php
+++ b/src/sammo/Util.php
@@ -65,7 +65,7 @@ class Util extends \utilphp\util{
             }
             return intval($val);
         }
-        throw new InvalidArgumentException('올바르지 않은 타입형 :'.$val);
+        throw new \InvalidArgumentException('올바르지 않은 타입형 :'.$val);
     }
 
     /**
@@ -125,7 +125,7 @@ class Util extends \utilphp\util{
         }
         $idx = 0;
         $jmp = 0;
-        foreach ($arr as $key=>&$value) {
+        foreach ($array as $key=>&$value) {
             if(is_string($key)){
                 return true;
             }
@@ -156,7 +156,7 @@ class Util extends \utilphp\util{
             return $dict;
         }
     
-        foreach ($arr as $key=>$value) {
+        foreach ($dict as $key=>$value) {
             if($value === null){
                 unset($dict[$key]);
             }
@@ -209,9 +209,9 @@ class Util extends \utilphp\util{
     /**
      * 각 값의 비중에 따라 랜덤한 값을 선택
      * 
-     * @param array 각 수치의 비중
+     * @param array $items 각 수치의 비중
      * 
-     * @return object 선택된 랜덤 값의 key값. 단순 배열인 경우에는 index
+     * @return int|string 선택된 랜덤 값의 key값. 단순 배열인 경우에는 index
      */
     public static function choiceRandomUsingWeight(array $items){
         $sum = 0;
@@ -235,7 +235,7 @@ class Util extends \utilphp\util{
     /**
      * 배열의 아무거나 고름. Python의 random.choice()
      * 
-     * @param array 선택하고자 하는 배열
+     * @param array $items 선택하고자 하는 배열
      * 
      * @return object 선택된 value값.
      */
diff --git a/src/sammo/WebUtil.php b/src/sammo/WebUtil.php
index bb5f2556..236354ce 100644
--- a/src/sammo/WebUtil.php
+++ b/src/sammo/WebUtil.php
@@ -2,6 +2,11 @@
 namespace sammo;
 
 class WebUtil{
+
+    private function __construct(){
+
+    }
+
     public static function escapeIPv4($ip){
         return str_replace('.', '\\.', $ip);
     }
@@ -19,13 +24,13 @@ class WebUtil{
         // http://thisinterestsme.com/receiving-json-post-data-via-php/
         // http://thisinterestsme.com/php-json-error-handling/
         if(strcasecmp($_SERVER['REQUEST_METHOD'], 'POST') != 0){
-            throw new Exception('Request method must be POST!');
+            throw new \Exception('Request method must be POST!');
         }
         
         //Make sure that the content type of the POST request has been set to application/json
         $contentType = isset($_SERVER["CONTENT_TYPE"]) ? trim($_SERVER["CONTENT_TYPE"]) : '';
         if(strcasecmp($contentType, 'application/json') != 0){
-            throw new Exception('Content type must be: application/json');
+            throw new \Exception('Content type must be: application/json');
         }
         
         //Receive the RAW post data.
@@ -39,7 +44,7 @@ class WebUtil{
         
         //In some cases, this will happen.
         if(is_null($decoded) && $jsonError == JSON_ERROR_NONE){
-            throw new Exception('Could not decode JSON!');
+            throw new \Exception('Could not decode JSON!');
         }
         
         //If an error exists.
@@ -67,7 +72,7 @@ class WebUtil{
                     $error .= 'Unknown error!';
                 break;
             }
-            throw new Exception($error);
+            throw new \Exception($error);
         }
     
         return $decoded;