This paper examines the feasibility of providing multimedia mail, in particular video mail, on the existing World-Wide-Web platform. In this instance,the Web browser will act as the user agent of the mailing system. W...This paper examines the feasibility of providing multimedia mail, in particular video mail, on the existing World-Wide-Web platform. In this instance,the Web browser will act as the user agent of the mailing system. With this,users will be able to compose, send and read video mail directly on the Web.This paper examines a number of different system architectures which can be employed for the development of Video Mail. Based on the following key issues:portability of system, flexibility of system, Internet standard support, securityand authentication, and message compression and storage, a final architecturewas chosen to build Video Mail. The approach taken is that the system will beinterfaced to the Web using a standard HyperText Transfer Protocol (HTTP)server and a standard Web browser. This is achieved through the use of Common Gateway interface (CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail, and a separate mail server for the storage and management of messages. This will cause the HTTP server to behave as if it is an electronic mail system. The paper also addresses implementation issues pertaining to the use of CGI programs, mail server development, and video and audio composition and playback.展开更多
Contextual logic provides a mechanism to reason about modules. In this paper, this theory of modules is extended to a context theory of classes where class is in the true spirit of object-oriented databases. The logic...Contextual logic provides a mechanism to reason about modules. In this paper, this theory of modules is extended to a context theory of classes where class is in the true spirit of object-oriented databases. The logic, referred to as CLOG,is class-based. CLOG supports class, object identity, multiple role of object,monotonic and non-monotonic inheritance of data a-nd method, method factor-ing, views, derived and query classes. Views and derived classes are queries in themselves- Objects are pure data terms representing the ground instances of facts in the class. 'Object identity is a first class term in the logic. Inheritance is handled through delegation.展开更多
文摘This paper examines the feasibility of providing multimedia mail, in particular video mail, on the existing World-Wide-Web platform. In this instance,the Web browser will act as the user agent of the mailing system. With this,users will be able to compose, send and read video mail directly on the Web.This paper examines a number of different system architectures which can be employed for the development of Video Mail. Based on the following key issues:portability of system, flexibility of system, Internet standard support, securityand authentication, and message compression and storage, a final architecturewas chosen to build Video Mail. The approach taken is that the system will beinterfaced to the Web using a standard HyperText Transfer Protocol (HTTP)server and a standard Web browser. This is achieved through the use of Common Gateway interface (CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail, and a separate mail server for the storage and management of messages. This will cause the HTTP server to behave as if it is an electronic mail system. The paper also addresses implementation issues pertaining to the use of CGI programs, mail server development, and video and audio composition and playback.
文摘Contextual logic provides a mechanism to reason about modules. In this paper, this theory of modules is extended to a context theory of classes where class is in the true spirit of object-oriented databases. The logic, referred to as CLOG,is class-based. CLOG supports class, object identity, multiple role of object,monotonic and non-monotonic inheritance of data a-nd method, method factor-ing, views, derived and query classes. Views and derived classes are queries in themselves- Objects are pure data terms representing the ground instances of facts in the class. 'Object identity is a first class term in the logic. Inheritance is handled through delegation.
