ERD (Entity-Relationship Diagram) Explanation: The ERD is a high-level representation of the data relationships in the ConfPlus Conference Management System. It shows the main entities, their attributes, and the relationships between them. Entities: User: Represents a user in the system, including authors, reviewers, and organizers. Attributes include UserID, Name, Email, Password, Affiliation, and Role. Paper: Represents an academic paper submitted to the conference. Attributes include PaperID, Title, Abstract, PDF, and SubmissionDate. Authorship: Represents the relationship between a User (author) and a Paper. Attributes include AuthorshipID, UserID, PaperID, and IsPresenter (to indicate if the author is the presenter of the paper). Review: Represents a review assigned to a paper by a User (reviewer). Attributes include ReviewID, UserID, PaperID, OverallEvaluation, Contribution, Strengths, Weaknesses, and ReviewDate. Conference: Represents the conference itself. Attributes include ConferenceID, Name, StartDate, and EndDate. Session: Represents a conference session. Attributes include SessionID, ConferenceID, Title, Location, and Date. Presentation: Represents a paper presentation within a conference session. Attributes include PresentationID, SessionID, PaperID, PresenterUserID, and TimeSlot. Relationships: User - Authorship: One-to-Many (A user can be an author of multiple papers, and a paper can have multiple authors) Paper - Authorship: One-to-Many (A paper can have multiple authors, and an author can be associated with multiple papers) Paper - Review: One-to-Many (A paper can have multiple reviews, and a reviewer can review multiple papers) User - Review: One-to-Many (A user can review multiple papers, and a paper can be reviewed by multiple users) Conference - Session: One-to-Many (A conference can have multiple sessions) Session - Presentation: One-to-Many (A session can have multiple presentations) Paper - Presentation: One-to-One (Each presentation is associated with one paper) User - Presentation: One-to-One (Each presentation has one presenter) Class Diagram Explanation: The class diagram is a visual representation of the classes, their attributes, and methods in the ConfPlus Conference Management System. It provides an overview of how the system's functionalities are organized and implemented. Classes: User: Represents a user in the system, with attributes and methods for registration and login. Paper: Represents an academic paper, with attributes and a method for paper submission. Authorship: Represents the relationship between a User (author) and a Paper, with methods for adding and removing authors. Review: Represents a review assigned to a paper by a User (reviewer), with attributes and a method for reviewing a paper. Conference: Represents the conference itself, with attributes and a method for creating a conference. Session: Represents a conference session, with attributes and methods for adding, updating, and deleting sessions. Presentation: Represents a paper presentation within a conference session, with attributes and methods for scheduling, updating, and deleting presentations. Relationships: User - Authorship: A user can be an author of multiple papers. User - Review: A user can review multiple papers. Paper - Authorship: A paper can have multiple authors. Paper - Review: A paper can have multiple reviews. Conference - Session: A conference can have multiple sessions. Session - Presentation: A session can have multiple presentations. Paper - Presentation: Each presentation is associated with one paper. User - Presentation: Each presentation has one presenter (a user). The ERD and class diagram complement each other in providing a comprehensive view of the ConfPlus Conference Management System. While the ERD focuses on the data structure and relationships between entities, the class diagram outlines the classes, their attributes, and methods in the system. These diagrams will help you design the ConfPlus system, as they serve as a guide for implementing the various functionalities required to organize and manage an academic conference. Keep in mind that these diagrams provide a high-level overview, so you will still need to consider implementation details like error handling, input validation, and user interface design. Additionally, you may want to use a modern web development framework and a database management system to build and deploy the ConfPlus system. Please I have ER diagram Need only class diagram with methods