Ashok U. Mallya

Resolving Commitments among Autonomous Agents

Commitments are a powerful representation for modeling multiagent interactions. Previous approaches have considered the semantics of commitments and how to check compliance with them. However, these approaches do not capture some of the subtleties that arise in real-life applications, e.g., e-commerce, where contracts and institutions have implicit temporal references. The present paper develops a rich representation for the temporal content of commitments. This enables us to capture realistic contracts and institutions rigorously, and avoid subtle ambiguities. Consequently, this approach enables us to reason about whether and when exactly a commitment is satisfied or breached and whether it is or ever becomes unenforceable.

The IEEE FIPA approach to integrating software agents and web services

In many settings Web services are now perceived as the first choice technology to provide neatly encapsulated functionality for Web-based computation. To date, many standards have been produced and adoption is accelerating across numerous application domains. This uptake has long been recognized by members of software agent community with several approaches reported that explore various means of extending the utility of Web services with the autonomous control offered by agents. This paper reports on the recent work of several members of this community to consolidate their approaches into a common specification describing how to seamlessly interconnect FIPA compliant agent systems with W3C compliant Web services. This work has been conducted within the context of the IEEE FIPA Agent and Web Service Integration working group and will be shortly published as a new FIPA specification.

An algebra for commitment protocols

Protocols enable unambiguous, smooth interactions among agents. Commitments among agents are a powerful means of developing protocols. Commitments enable flexible execution of protocols and help agents reason about protocols and plan their actions accordingly, while at the same time providing a basis for compliance checking. Multiagent systems based on commitments can conveniently and effectively model business interactions because the autonomy and heterogeneity of agents mirrors real-world businesses. Such modeling, however, requires multiagent systems to host a rich variety of protocols that can capture the needs of different applications. We show how a commitment-based semantics provides a basis for refining and aggregating protocols. We propose an approach for designing commitment protocols wherein traditional software engineering notions such as refinement and aggregation are extended to apply to protocols. We present an algebra of protocols that can be used to compose protocols by refining and merging existing ones, and does this at a level of abstraction high enough to be useful for real-world applications.

Commitments among agents

Commitments are a powerful representation for modeling multiagent interactions. Previous approaches have considered the semantics of commitments and how to check compliance with them. However, these approaches do not capture some of the subtleties that arise in real-life applications such as e-commerce, in which contracts and institutions have implicit temporal references. In this column, we describe a rich representation for the temporal content of commitments that lets us capture realistic contracts and avoid ambiguities. Consequently, this approach lets us reason about whether, and at what point, a commitment is satisfied or breached, and whether it is or ever becomes unenforceable.

Modeling exceptions via commitment protocols

This paper develops a model for exceptions and an approach for incorporating them in commitment protocols among autonomous agents. Modeling and handling exceptions is critical for successful applications of multiagent systems. Protocols help build multiagent systems, but traditional representations (such as finite state machines or Petri nets) inadequately model complex interactions and exceptions therein. Emerging commitment-based representations are promising, because they declaratively reflect the semantics of an interaction. However, current approaches lack a strong treatment of exceptions.This paper treats both expected and unexpected exceptions. A commitment protocol is modeled as a set of computations, each representing an allowed interaction and showing the evolving commitments of the participants. Exceptions are modeled via preference structures induced on these sets of computations. The preference structures statically show how expected exceptions are handled whereas the structures must be enhanced dynamically to handle unexpected exceptions. Our approach includes operators for composing protocols and exception handlers, whereby appropriate exception handlers can be dynamically introduced into a protocol as needed.The main contributions of this paper are (1) a framework for modeling and handling exceptions intelligently in commitment protocols and (2) a demonstration of the benefits of commitment protocols over traditional formalisms in handling exceptions.

OWL-P: a methodology for business process development

Business process modelling and enactment are notoriously complex, especially in open settings where the business partners are autonomous, requirements must be continually finessed, and exceptions frequently arise because of real-world or organizational problems. Traditional approaches, which attempt to capture processes as monolithic flows, have proved inadequate in addressing these challenges. We propose an agent-based approach for business process modelling and enactment which is centred around the concepts of commitment-based agent interaction protocols and policies. A (business) protocol is a modular, public specification of an interaction among different roles. Such protocols, when integrated with the internal business policies of the participants, yield concrete business processes. We show how this reusable, refinable and evolvable abstraction simplifies business process design and development.

Protocols for processes: programming in the large for open systems

The modeling and enactment of business processes is being recognized as key to modern information managment. The expansion of Web services has increased the attention given to processes, because processes are how services are composed and put to good use. However, current approaches are inadequate for flexibly modeling and enacting processes. These approaches take a logically centralized view of processes, treating a process as an implementation of a composed service. They provide low-level scripting languages to specify how a service may be implemented, rather than what interactions are expected from it. Consequently, existing approaches fail to adequately accommodate the essential properties of the business partners in a process (the partners would be realized via services)---their autonomy (freedom of action), heterogeneity (freedom of design), and dynamism (freedom of configuration).Flexibly represented protocols can provide a more natural basis for specifying processes. Protocols specify what rather than how; thus they naturally maximize the authonomy, heterogeneity, and dynamism of the interacting parties. We are developing an approach for modeling and enacting business processes based on protocols. This paper describes some elements of (1) a conceptual model of processes that will incorporate abstractions based on protocols, roles, and commitments; (2)the semantics or mathematical foundations underlying the conceptual model and mapping global views of processes to the local actions of the parties involved; (3) methodologies involving rule-based reasoning to specify processes in terms of compositions of protocols.

A Semantic Approach for Designing Commitment Protocols

Protocols enable unambiguous and smooth interactions among agents. Multiagent systems need to host a rich variety of interaction protocols if they are to model the needs of real-world applications such as business processes. Commitments allow flexible execution of protocols, while at the same time providing a basis for compliance checking. We propose conceptual abstractions for commitmentbased protocols similar to those used in information models, specifically (1) refinement: a subprotocol may satisfy the requirements of a superprotocol but support additional properties; and (2) aggregation: a protocol may combine existing protocols. We develop an algebra of protocols that can be used to compose protocols by refining and merging existing ones at a level of abstraction high enough to be useful for real-world applications.

Introducing Preferences into Commitment Protocols

Commitment protocols enable flexibility in agent interactions by utilizing the semantics of commitments to develop succinct declarative specifications for protocols that allow a large number of executions. As a consequence, commitment protocols enable agents to accommodate varying local policies and respond to exceptions. A consequent weakness of such protocols is that commitment protocols thus fail to distinguish between possible executions that are normal and those that may be allowed but are not ideal. This paper develops an approach for specifying preferencesamong executions that are allowed by a protocol. It captures sets of executions via a simple language and gives them a denotational characterization based on branching-time models. It shows how to incorporate the specifications into rulesets, thereby giving the specifications a natural operational characterization. The rulesets embed into a recent practical framework for protocols called OWL-P. The paper shows that the operational and denotational characterizations coincide.

Protocols for processes: programming in the large for open systems (extended abstract)

The modeling and enactment of business processes is being recognized as key to modern information management. The expansion of Web services has increased the attention given to processes, because processes are how services are composed and put to good use. However, current approaches are inadequate for flexibly modeling and enacting processes. These approaches take a logically centralized view of processes, treating a process as an implementation of a composed service. They provide low-level scripting languages to specify how a service may be implemented, rather than what interactions are expected from it. Consequently, existing approaches fail to adequately accommodate the essential properties of the business partners in a process (the partners would be realized via services)---their <i>autonomy</i> (freedom of action), <i>heterogeneity</i> (freedom of design), and <i>dynamism</i> (freedom of configuration). Flexibly represented <i>protocols</i> can provide a more natural basis for specifying processes. Protocols specify <i>what</i> rather than <i>how</i>; thus they naturally maximize the autonomy, heterogeneity, and dynamism of the interacting parties. We are developing an approach for modeling and enacting business processes based on protocols. This paper describes some elements of (1) a conceptual model of processes that will incorporate abstractions based on protocols, roles, and commitments; (2) the semantics or mathematical foundations underlying the conceptual model and mapping global views of processes to the local actions of the parties involved; (3) methodologies involving rule-based reasoning to specify processes in terms of compositions of protocols.