The high level of English is a standard for a top student.

1. IELTS helps you select the right people from around the world (https://www.ielts.org/online-tutorial/overview/page2)　

The International English Language Testing System (IELTS) is designed to test the English language abilities of non-native speakers who plan to study or work where English is the language of communication.

IELTS is accepted by over 10,000 organisations around the world, and more than 3 million IELTS tests were taken worldwide in the last year.

Organisations that accept IELTS results include:

• all universities and the vast majority of education providers in Australia, New Zealand and the UK (and most in Canada)
• more than 3,000 institutions in the US (including Ivy League universities)
• immigration authorities in Australia, Canada, New Zealand and the UK
• professional registration bodies worldwide, covering areas such as accounting, engineering, law, medicine and nursing
• a wide range of employers from sectors such as banking and finance, government, construction, energy and natural resources, aviation, health and tourism
• universities in non-English speaking countries where English is the language of instruction.

1. We want qualified applicants who can communicate effectively. The IELTS examination is a strong, well-constructed test that caters to this demand.

3. IELTS makes the world a bigger, more open place. Learning English has transformed me into a citizen of the world.

4. IELTS gives a reliable indication of entry level English Proficiency. Other tests are less satisfactory at providing this.

5.The loneliest place on earth is looking in a mirror and being ashamed of who you see.

Configuring and Using the Navigation Stack

1. Setting up your robot using tf （http://wiki.ros.org/navigation/Tutorials/RobotSetup/TF）

2. Basic Navigation Tuning Guide （http://wiki.ros.org/navigation/Tutorials/Navigation%20Tuning%20Guide）

3. Setup and Configuration of the Navigation Stack on a Robot （http://wiki.ros.org/navigation/Tutorials/RobotSetup）

Description: This tutorial provides step-by-step instructions for how to get the navigation stack running on a robot. Topics covered include: sending transforms using tf, publishing odometry information, publishing sensor data from a laser over ROS, and basic navigation stack configuration.

4. Using rviz with the Navigation Stack （http://wiki.ros.org/navigation/Tutorials/Using%20rviz%20with%20the%20Navigation%20Stack）

5. Publishing Odometry Information over ROS （http://wiki.ros.org/navigation/Tutorials/RobotSetup/Odom）

6. Publishing Sensor Streams Over ROS （http://wiki.ros.org/navigation/Tutorials/RobotSetup/Sensors）

原文地址：https://www.cnblogs.com/sancai16888/p/9682692.html