The introduction is to set a theme for the paper, with the purpose of leading to the following research content. It should:

  (1) Introduce the background, significance, development status and current level of a research field;

  (2) Review and summarize the literature in relevant fields, including previous research and solved problems, and properly evaluate or compare them;

  (3) Point out the problems that have not been solved and the technical gaps left by the previous researches, and also put forward new problems, new methods and new ideas to solve these new problems, thus leading to the motivation and significance of this research;

  (4) Explain the purpose of the research;

  (5) Summarize the main content of the paper or give its general outline.