We are sorry to inform you that, in response to the continued severity of COVID-19, the nationwide Level 3 epidemic alert will be extended to June 28. All unnecessary activities gatherings involving over 5 people indoors or 10 people outdoors are suspended. Thus ICEO&SI 21is scheduled to postponed to late July and will take measures depends on the situation. Important Notes: 1. All submitted abstracts have been reviewed and the notification have been sent to all corresponding authors. For those who have completed the submission but not received any notification before June 7, please contact us as soon as possible. 2. Every abstract should be submitted by one author who have completed the registration. And one author who have completed the registration could only present one abstract. Multiple abstracts being presented by one author is not allowed. 3. All presenters must complete the registration before June 14, or the abstract will be withdrawn. 4. All presenters complete the registration by June 10 enjoy early-bird rate. 5. For those who need registration receipt before conference, please reply this email with your recipient address and post code. 6.For those who need to present to obtain degree, please feel free to contact us.