diff --git a/app/controllers/comments_controller.rb b/app/controllers/comments_controller.rb
index 4088d4156..6b421bf2a 100644
--- a/app/controllers/comments_controller.rb
+++ b/app/controllers/comments_controller.rb
@@ -49,6 +49,9 @@ class CommentsController < ApplicationController
       # end
       # # ������ض�̬�ļ�¼add end
       flash[:notice] = l(:label_comment_added)
+      user_activity = UserActivity.where("act_type='News' and act_id =#{@news.id}").first
+      user_activity.updated_at = @comment.created_on
+      user_activity.save
     end
 
     if params[:user_activity_id]
diff --git a/app/controllers/issues_controller.rb b/app/controllers/issues_controller.rb
index 47e425710..bf854abe8 100644
--- a/app/controllers/issues_controller.rb
+++ b/app/controllers/issues_controller.rb
@@ -394,6 +394,9 @@ class IssuesController < ApplicationController
       jour.notes = params[:notes]
       jour.journalized = @issue
       jour.save
+      user_activity = UserActivity.where("act_type='Issue' and act_id =#{@issue.id}").first
+      user_activity.updated_at = jour.created_on
+      user_activity.save
       @user_activity_id = params[:user_activity_id]
       respond_to do |format|
         format.js
diff --git a/app/controllers/messages_controller.rb b/app/controllers/messages_controller.rb
index 9b0fd56a0..aae33e52a 100644
--- a/app/controllers/messages_controller.rb
+++ b/app/controllers/messages_controller.rb
@@ -161,6 +161,9 @@ class MessagesController < ApplicationController
     @reply.content = @quote + @reply.content
     @reply.subject = "RE: #{@topic.subject}" unless params[:reply][:subject]
     @topic.children << @reply
+    user_activity = UserActivity.where("act_type='Message' and act_id =#{@topic.id}").first
+    user_activity.updated_at = @reply.created_on
+    user_activity.save
     #@topic.update_attribute(:updated_on, Time.now)
     if !@reply.new_record?
       if params[:asset_id]
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 4796d0c0c..91518eaca 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -853,24 +853,24 @@ class UsersController < ApplicationController
     if params[:type].present?
       case params[:type]
         when "course_homework"
-          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'HomeworkCommon'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'HomeworkCommon'").order('updated_at desc').limit(10).offset(@page * 10)
         when "course_news"
-          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'News'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'News'").order('updated_at desc').limit(10).offset(@page * 10)
         when "course_message"
-          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'Message'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'Message'").order('updated_at desc').limit(10).offset(@page * 10)
         when "course_poll"
-          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'Poll'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Course' and container_id in #{user_course_ids} and act_type = 'Poll'").order('updated_at desc').limit(10).offset(@page * 10)
         when "project_issue"
-          @user_activities = UserActivity.where("container_type = 'Project' and container_id in #{user_project_ids} and act_type = 'Issue'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Project' and container_id in #{user_project_ids} and act_type = 'Issue'").order('updated_at desc').limit(10).offset(@page * 10)
         when "project_message"
-          @user_activities = UserActivity.where("container_type = 'Project' and container_id in #{user_project_ids} and act_type = 'Message'").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("container_type = 'Project' and container_id in #{user_project_ids} and act_type = 'Message'").order('updated_at desc').limit(10).offset(@page * 10)
         when "current_user"
-          @user_activities = UserActivity.where("user_id = #{@user.id} and ((container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types}))").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("user_id = #{@user.id} and ((container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types}))").order('updated_at desc').limit(10).offset(@page * 10)
         else
-          @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types})").order('created_at desc').limit(10).offset(@page * 10)
+          @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types})").order('updated_at desc').limit(10).offset(@page * 10)
       end
     else
-      @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types})").order('created_at desc').limit(10).offset(@page * 10)
+      @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types})").order('updated_at desc').limit(10).offset(@page * 10)
     end
     # @user_activities = paginateHelper @user_activities,500
     @type = params[:type]
diff --git a/app/views/users/_user_activities.html.erb b/app/views/users/_user_activities.html.erb
index bbef67e6d..9eefbd1f1 100644
--- a/app/views/users/_user_activities.html.erb
+++ b/app/views/users/_user_activities.html.erb
@@ -11,7 +11,7 @@
     .ke-inline-block{display: none;}
     div.ke-container{float:left;}
 </style>
-<% first_user_activity = user_activities.first.id %>
+<% first_user_activity = user_activities.first.id unless user_activities.first.nil? %>
 <% user_activities.each do |user_activity|
   if user_activities %>
         <script>
@@ -31,10 +31,10 @@
                 }
             }
 
-            function expand_reply_input(id) {
-                $(id).toggle();
-            }
-
+            function expand_reply_input(id) {
+                $(id).toggle();
+            }
+
             $(function() {
                 init_KindEditor_data(<%= user_activity.id%>,"30px","85%");
             });
@@ -45,22 +45,22 @@
             <% if act  %>
                 <% case user_activity.act_type.to_s %>
                 <% when 'HomeworkCommon' %>
-                    <%= render :partial => 'course_homework', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'course_homework', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% when 'News' %>
-                    <%= render :partial => 'course_news', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'course_news', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% when 'Message'%>
-                    <%= render :partial => 'course_message', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'course_message', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% when 'Poll' %>
-                    <%= render :partial => 'course_poll', :locals => {:activity => act, :user_activity_id => user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'course_poll', :locals => {:activity => act, :user_activity_id => user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% end %>
             <% end %>
         <% when 'Project' %>
             <% if act  %>
                 <% case user_activity.act_type.to_s %>
                 <% when 'Issue' %>
-                    <%= render :partial => 'project_issue', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'project_issue', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% when 'Message' %>
-                    <%= render :partial => 'project_message', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
+                    <%= render :partial => 'project_message', :locals => {:activity => act,:user_activity_id =>user_activity.id,:first_user_activity =>first_user_activity,:page => page} %>
                 <% end %>
             <% end %>
         <% end %>
diff --git a/db/migrate/20150917071652_update_user_activities_update_at.rb b/db/migrate/20150917071652_update_user_activities_update_at.rb
new file mode 100644
index 000000000..7fbd425f4
--- /dev/null
+++ b/db/migrate/20150917071652_update_user_activities_update_at.rb
@@ -0,0 +1,16 @@
+class UpdateUserActivitiesUpdateAt < ActiveRecord::Migration
+  def up
+    count = UserActivity.all.count / 30 + 2
+    transaction do
+      for i in 1 ... count do i
+      UserActivity.page(i).per(30).each do |activity|
+        activity.updated_at = activity.created_at
+        activity.save
+      end
+      end
+    end
+  end
+
+  def down
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index b696765f8..a3c8277bb 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20150911064528) do
+ActiveRecord::Schema.define(:version => 20150917071652) do
 
   create_table "activities", :force => true do |t|
     t.integer  "act_id",                                  :null => false
@@ -476,13 +476,6 @@ ActiveRecord::Schema.define(:version => 20150911064528) do
 
   add_index "delayed_jobs", ["priority", "run_at"], :name => "delayed_jobs_priority"
 
-  create_table "discuss_demos", :force => true do |t|
-    t.string   "title"
-    t.text     "body"
-    t.datetime "created_at", :null => false
-    t.datetime "updated_at", :null => false
-  end
-
   create_table "documents", :force => true do |t|
     t.integer  "project_id",                :default => 0,  :null => false
     t.integer  "category_id",               :default => 0,  :null => false
@@ -497,26 +490,23 @@ ActiveRecord::Schema.define(:version => 20150911064528) do
   add_index "documents", ["created_on"], :name => "index_documents_on_created_on"
   add_index "documents", ["project_id"], :name => "documents_project_id"
 
-  create_table "dts", :primary_key => "Num", :force => true do |t|
-    t.string   "Defect",        :limit => 50
-    t.string   "Category",      :limit => 50
-    t.string   "File"
-    t.string   "Method"
-    t.string   "Module",        :limit => 20
-    t.string   "Variable",      :limit => 50
-    t.integer  "StartLine"
-    t.integer  "IPLine"
-    t.string   "IPLineCode",    :limit => 200
-    t.string   "Judge",         :limit => 15
-    t.integer  "Review",        :limit => 1
+  create_table "dts", :force => true do |t|
+    t.string   "IPLineCode"
     t.string   "Description"
-    t.text     "PreConditions", :limit => 2147483647
-    t.text     "TraceInfo",     :limit => 2147483647
-    t.text     "Code",          :limit => 2147483647
+    t.string   "Num"
+    t.string   "Variable"
+    t.string   "TraceInfo"
+    t.string   "Method"
+    t.string   "File"
+    t.string   "IPLine"
+    t.string   "Review"
+    t.string   "Category"
+    t.string   "Defect"
+    t.string   "PreConditions"
+    t.string   "StartLine"
     t.integer  "project_id"
-    t.datetime "created_at"
-    t.datetime "updated_at"
-    t.integer  "id",                                  :null => false
+    t.datetime "created_at",    :null => false
+    t.datetime "updated_at",    :null => false
   end
 
   create_table "enabled_modules", :force => true do |t|
@@ -916,6 +906,7 @@ ActiveRecord::Schema.define(:version => 20150911064528) do
     t.datetime "created_on"
     t.integer  "comments_count",               :default => 0,  :null => false
     t.integer  "course_id"
+    t.datetime "updated_on"
   end
 
   add_index "news", ["author_id"], :name => "index_news_on_author_id"