Read the following scenario and use your knowledge in the information system, critical thinking, and skills you gained from accounting information systems course in general and chapter seven in particular to discuss and to show your opinion regarding the below Walmart Company's case: During your evaluation for the reliability and security of Walmart Company information system, you have found that the reliability of the information system is not trusted, and both the company management and stakeholders do not relay on the system to acquire needed information for decision making process as they feel that the information system is vulnerable. By additional investigation you have concluded you became more certain that lacking the security is the main problem. Although the company has control system including preventive control, detective control and corrective control, some hackers attacked the system and transferred some money from the company account and obtain other business secrets. Therefore, the company information system is not reliable and needs better control system to be used. The significant weakness points you have discovered are: (1) the access control matrix is weak, and some employees who retired years ago can access the company system and display, update, delete and add data. (2) the time-based model of security is ineffective. In your opinion: (1) What is the security shortage in the access control matrix? (2) What is the meaning of the time-based model of security is ineffective? (3) How to fix the shortage in the access control matrix? (4) How to make the time-based model of security effective? (5) What you subject as a framework may be adopted it the future in Walmart Company to contribute to systems reliability? (6) What do you think the five basic principles to insure reliability in any accounting information system? (7) Do you think that the concept "Defense in Depth" can help to enhance the security level in Walmart Company? If yes, explain. (8) Do you think that the top management in Walmart Company has effective role to support and enhance information system reliability? If yes, explain.