Douglas B. Terry

Extending document management systems with user-specific active properties

Document properties are a compelling infrastructure on which to develop document management applications. A property-based approach avoids many of the problems of traditional heierarchical storage mechanisms, reflects document organizations meaningful to user tasks, provides a means to integrate the perspectives of multiple individuals and groups, and does this all within a uniform interaction framework. Document properties can reflect not only categorizations of documents and document use, but also expressions of desired system activity, such as sharing criteria, replication management, and versioning. Augmenting property-based document management systems with active properties that carry executable code enables the provision of document-based services on a property infrastructure. The combination of document properties as a uniform mechanism for document management, and active properties as a way of delivering document services, represents a new paradigm for document management infrastructures. The Placeless Documents system is an experimental prototype developed to explore this new paradigm. It is based on the seamless integration of user-specific, active properties. We present the fundamental design approach, explore the challenges and opportunities it presents, and show our architectures deals with them.

An overview of the Etherphone system and its applications

The Etherphone system has been developed to explore methods for extending existing multimedia office environments with the facilities needed to handle the transmission, storage, and manipulation of voice. Based on a hardware architecture that uses microprocessor-controlled telephones to transmit voice over an Ethernet that also supports a voice file server and a voice synthesis server, this system has been used for applications such as directory-based call placement, call logging, call filtering, and automatic call forwarding. Voice mail, voice annotation of multimedia documents, voice editing using standard text-editing techniques, and applications of synthetic voice use the Etherphones for voice transmission. Recent work has focused on the creation of a comprehensive voice system architecture, both to specify programming interfaces for custom uses of voice, and to specify the roles of different system components, so that equipment from multiple vendors could be integrated to provide sophisticated voice services.<<ETX>>

Delegation through access control programs

Access control programs (ACPs), which permit controlled delegation of access rights to untrusted computer hosts, are discussed. Existing delegation protocols for distributed systems provide a way for a client to transfer its access rights to an intermediary, but provide only limited facilities for restricting the rights granted to the intermediary. ACPs are small programs that encode arbitrary specifications of delegated access rights. They are created and digitally signed by a client and passed to a server through an intermediary. When processing a request from the intermediary, the server executes the access control program to decide whether or not to grant the intermediarys request. Examples of ACPs used in a variety of applications are presented. A sample implementation of ACPs in the Andrew File System is described.<<ETX>>