Distributed Collaborations Using Network Mobile Agents

1. Distributed Collaborations Using Network Mobile Agents • Anand Tripathi, Tanvir Ahmed, Vineet Kakani • and Shremattie Jaman • Department of computer science • University of Minnesota, Minneaplis MN 55455

3. Anand Tripathi Professor Department of  Computer Science & Engineering University of Minnesota Minneapolis MN 55455   Program Chair for IEEE 20th Symposium on Reliable Distributed Systems (SRDS 2001) October  2001

4. Content • Introduction • Overview of the Approach • Description of a Collaboration Plan • Collaboration Using Network Agents • Related Work • Conclusion • Feature Work

5. Introduction Focus On: Building Distributed Collaborations Using Mobile Agent Distributed Collaborations: *a number of physically distributed users *cooperate on some common tasks *share an environment composed of objects Mobile Agents: *an object capable of migrating autonomously *perform tasks on behalf of a user

6. Introduction Motivations: *ensure members participate only by using prescribed protocols *can execute remote coordination operations *be shared objects in workflow system *migrating the user’s agent instead of moving the user physically

7. Introduction Contributions: *develop a methodology for building a distributed collaboration environment with *specifying a collaboration plan using XML then *interfacing such a specification with a mobile agent based middleware Important features: *designers need to specify only the XML plan without *being concerned about the management of the mobile coordination agents and *the security issues

8. Approach Design Steps First Step: *using DTD for defining roles, shared objects, and operations associated with a collaborative task *providing rules for associating privileges with roles, and coordination actions with operations

9. Elements Participant Roles: a set of responsibilities and tasks for a participant towards the goal of the collaborative activity. Shared Objects: a collaborative activity whose operations are executed by the participants based on their roles. Privileges: the security policies in a collaboration that are based on the participants’ roles. Coordination Operations: actions to be executed when a certain task is required in the collaboration.

10. Approach Design Steps Second Step: *using XML for specifying the collaboration plan, in conformance with the rules given by the DTD. *the convener is responsible for preparing this specification.

11. Approach Design Steps Third Step: * realizing a distributed collaboration using mobile agents.

12. Approach Design Steps Third Step: realizing a distributed collaboration using mobile agents. UCI: User Coordination Interface • UCI is constructed as a collection of mobile agents obtained from the convener. • When a certain task is executed, UCI dispatches agents to other UCIs, also it receives and executes agents come from other UCIs.

13. Approach Design Steps Third Step: * realizing a distributed collaboration using mobile agents.

14. Example: A Collaborative Authoring System • Task: writing, reviewing, and editing different parts of the document • Three roles: author, editor, and reviewer • Shared objects: the chapter’s contents, the reviewer’s comment and the editor’s comment. • Coordination operations: • At chapter level • At reviewer level • At editor level

15. About XML (eXtensible Markup Language) *XML is a project of the World Wide Web Consortium (W3C), and the development of the specification is being supervised by their XML Working Group. A Special Interest Group of co-operation contributors and experts from various fields contributed comments and reviews by email. *XML is a public format: it is not a proprietary development of any company. The v1.0 specification was accepted by the W3C as Recommendation on Feb 10, 1998.

16. Features of XML • XML is • Extensible • introduce your own tags • Portable • DTD (Document Type Definition) • Structured • Need to follow the grammar specified in DTD • Descriptive . The elements are free to describe the meaning of what they contain

17. About DTD (Document Type Descriptor) • DTD is a set of rules that defines what tags appear in a XML document • DTDs are used to describe the structure of XML document. • a DTD can be considered as a database schema (schema of object-oriented or object-relational databases) if a XML document is considered as a database.

18. Some Symbol in DTD <!DOCTYPE : declaration of the document type [ : marks the start of the DTD <!ELEMENT : define tag and its relation with other tags (elements) <!ATTLIST : attribute of a element +, *, ?, | : symbols represent the elements allowed +, elements must be used one or more times *, elements is optional and can be used multiple times ?, optional but if use, only use once | , use either elements but not both #PCDATA : insert text ]> : end of DTD

19. Description of a Collaboration plan

20. An Example of Collaboration Plan Specification

21. An Example of Collaboration Plan Specification

22. About Ajanta • Ajanta is a Java-based system for programming mobile agents in distributed system. • The Ajanta system provides facilities to build customizable servers to host mobile agents, and a set of primitives for the creation and management of agents. • Support for security is an integral part of the Ajanta system.

23. About Ajanta--Main Component • Agent • Agent-server • Name-registry

24. Ajanta’s Main Component--Agent • It implements the generic functionality of a mobile agent. • It can request various from its local host. • It can request migration to another host. • It supports the concept of itineraries.

25. Ajanta’s Main Component--AgentServer • It provides the generic functionality to host agents. • It creates protected domains for their execution . • It transfers agents from one server to another. • It respond to various agent control functions.

27. Ajanta’s Main Component--Name Registry The servermaintains a domain registry, which is a simple database that keeps track ofthe agents currently executing on it. 

28. Implementation of the Collaborative Authoring System • Each user performs his tasks in the collaboration through the UCI • In this paper the approach is to implement a UCI by extending Ajanta’ AgentServer class. • Programmers can extend AgentServer class by writing a subclass of AgentServer

29. Implementation of the Collaborative Authoring System • Each user performs his tasks in the collaboration through the UCI • In this paper the approach is to implement a UCI by extending Ajanta’ AgentServer class. • Programmers can extend AgentServer class by writing a subclass of AgentServer

30. Implementation of the Collaborative Authoring System The Structure of a UCI: A document manager object: It reads the XML plan; It maintains the shared object space; Its interface enables the user and the visiting agents to process any part of a document User interface object: It is implemented as a collection of mobile agents; Through the user interface, operation of the document manager are executed

31. Implementation of the Collaborative Authoring System

32. Related Work • Mobile agent system • Computer-supported collaborative work • Coordination specification • Workflow management • Role-based security

33. Conclusion • The main contribution of this paper is in developing a methodology for building a distributed collaboration system using a high level specification in XML, and then interfacing this specification with a mobile agent based middleware to realize the desired system.

34. Future Work • Developing a general application level exception handling model • Developing a more general collaboration specification in XML

35. Thanks