http://techbooster.jpn.org/application/1517/
http://developer.android.com/reference/android/app/ActivityManager.RunningTaskInfo.html
http://developer.android.com/guide/topics/security/security.html
http://developer.android.com/reference/android/content/pm/PackageManager.html#getInstalledApplications(int)
http://developer.android.com/reference/android/content/ComponentName.html