Suhayya Abu-Hakima

Using Knowledge in Its Context: Report on the IJCAI-93 Workshop

The Workshop on Using Knowledge in Its Context was held in Chambery, France, on 28 August 1993, preceding the Thirteenth International Joint Conference on Artificial Intelligence (IJCAI-93). This article provides a summary of the discussions between the participants before (by e-mail) and during the one-day workshop. It is clear from these discussions that the notion of context is far from defined and is dependent in its interpretation on a cognitive science versus an engineering (or system building) point of view. In identifying the two points of view, this workshop permitted us to go one step further than previous workshops (notably Maskery and Meads [1992] and Maskery, Hopkins, and Dudley [1992]). Once a distinction is made on the viewpoint, one can achieve a surprising consensus on the aspects of context that the workshop addressed -- mainly, the position, the elements, the representation, and the use of context. Despite this consensus on the aspects of context, agreement on the definition of context was not yet achieved.

A common multi-agent testbed for diverse seamless personal information networking applications

This article describes the design and implementation of a unique cooperative agents testbed aimed at addressing diverse applications for the difficult problem of seamless personal information networking (SPIN). The real-world SPIN testbed is aimed at two difficult applications. Namely seamless messaging and intelligent network management. Both applications are agent-driven and share agent behavior, and the messaging agents rely on the network management device diagnostic agents for input. The article introduces both problem areas in a common testbed. The first-generation seamless messaging application is described in detail. User-centric seamless messaging assumes heterogeneous communication environments intended to support todays nomadic users. The prototype is introduced for the management of messages across distributed information networks. Its aim is to intercept, filter, interpret, and deliver multimodal messages, be they voice, fax, video, and/or e-mail messages. A users personal communication agent is charged with delivering messages to the recipient regardless of their target messaging device-a telephone, pager, desktop, wireless laptop, or wireless phone. Personal communication agents classify and act on incoming messages based on their content. A secretary agent routes and tailors urgent messages appropriately to the device manager agent, which delivers the message to a device on which the user may be roaming or active. What makes the seamless messaging application unique is its approach to treating a message in a universal manner, and its ability to mediate between different messaging environments and devices, and to try to track and find the user.

Improving explanations in knowledge-based systems: RATIONALE

The paper describes a framework, RATIONALE, for building knowledge-based diagnostic systems that explain by reasoning explicitly. Unlike most existing explanation facilities that are grafted onto an independently designed inference engine, RATIONALE behaves as though it has to deliberate over and explain to itself, each refinement step. By treating explanation as primary, RATIONALE forces the system designer to represent knowledge explicitly that might otherwise be left implicit. This includes knowledge as to why a particular hypothesis is preferred, an exception is ignored, and a global inference strategy is chosen. RATIONALE integrates explanations with reasoning by allowing a causal and/or functional description of the domain to be represented explicitly. Reasoning proceeds by constructing a hypothesis-based classification tree whose root hypothesis contains the most general diagnosis of the system. Guided by a focusing algorithm, the classification tree branches into more specific hypotheses that explain the more detailed symptoms provided by the user. As the system is used, the classification tree also forms the basis for a dynamically generated explanation tree which holds both the successful and failed branches of the reasoning knowledge. RATIONALE is implemented in Quintus Prolog with a hypertext and graphics oriented interface under NeWS. It provides an environment for tying together the processes of knowledge acquisition, system implementation and explanation of system reasoning.

JETA: A knowledge-based approach to aircraft gas turbine engine maintenance

Aircraft gas turbine engine maintenance is a complex task requiring not only specialized technical skill but effective integration of many sources of information. Traditionally, military maintenance technicians make extensive use of common sense knowledge, equipment manuals, pilot reports, instrument readings, engine settings and physical observations. Reasoning based upon patterns in sensor data, case histories and past maintenance is infrequently carried out. Difficulties in maintenance arise from the need to quickly restore the engines to an operational state, the frequent reassignment of technicians and the awkward access to, and interpretation of, data. There is a need to overcome these factors.This paper describes a knowledge-based diagnostic system for military gas turbine aero-engines. The objectives were to develop a system which encodes the heuristics of technicians and to provide an expandable framework for automating the technical manuals and incorporating explanations, data interpretation, as well as case history and model-based reasoning. The eventual goal is to apply the system to the maintenance of complex mechanical equipment and have it reason, in an on-line mode, with data obtained from a data acquisition system.A description of the application area and the features of the system, in its current stage of development, are discussed. This paper will be of practical benefit to those developing knowledge-based maintenance systems for complex mechanical equipment.

Agent negotiation for supporting personal mobility

Personal mobility — a fundamental characteristic of Nomadic Computing — creates an environment in which a user roams without a wireless laptop or a mobile phone and yet enjoys anytime, anywhere network accessibility. This paper gives an overview of Nomads Personal Access System (NPAS), OSI application layer software that provides a personal mobility environment within a virtual network. In addition, it focuses on the part of NPAS, called Site Profile Agent. Site Profile Agent is an inter-site negotiating agent that communicates with its peer to decide services for a nomad. This work is motivated by the larger project of the Mobile Agents Alliance, a collaboration that includes the National Research Council of Canada, the University of Ottawa, and Mitel Corp.

A Common Multi-agent Testbed for Diverse Seamless Personal Information Networking Applications

The paper describes the design and implementation of a unique cooperative agents testbed intended for diverse applications in seamless personal information networking. The real-world SPINTM1 testbed is aimed at two applications, namely seamless messaging and intelligent network management. Both are agent-driven and share agent behaviours. The messaging agents rely on the network management device diagnostic agents for input. The first generation of Seamless MessagingTM is described in detail. It is user-centric and assumes heterogeneous communication environments intended to support todays nomadic users. A prototype is introduced for the management of messages across distributed information networks. Its aim is to intercept, filter, interpret, and deliver multi-modal messages be they voice, fax, video and/or e-mail messages. A users Personal Communication AgentTM (PCA) is charged with delivering messages to the recipient regardless of their target messaging device be it a telephone, a pager, a desktop, a wireless laptop or a wireless phone. PCAs classify and act on incoming messages based on their content. A Secretary AgentTM routes and tailors urgent messages appropriately to the Device Manager AgentTM which delivers the message to a device that the user may be roaming or active on. What makes Seamless Messaging unique is its approach to treating a message in a universal manner, its ability to mediate between different messaging environments and devices, and its capability of tracking and finding users.

Jet engine technical advisor (JETA)

The paper describes a generalized knowledge-based tool for diagnosis which is currently being applied to jet engine maintenance. A domain dependent diagnostic tree is created for a particular jet engine by filling in an empty hypothesis frame for each diagnostic node in the tree. The knowledge in the tree is reasoned about using a generalized and explicit reasoning strategy. This strategy can be guided by rules specific to the activation of a particular diagnostic hypothesis in the tree. The user interacts with the system through a window interface which features definitions, glossary information, schematics and explanations of session reasoning, which are all linked to the knowledge contained in the system. A demonstration prototype which runs under the ART (LISP-based) environment on Symbolics 3620 and Sun 3/60 workstations was completed in December 1988. The preliminary prototype diagnoses a subset of the acceleration faults on the General Electric J85-CAN-15 jet engine and is being field tested and evaluated by potential users.

RATIONALE: reasoning by explaining

A methodology is presented for building knowledge-based systems that reason by explaining. The methodology is the basis for RATIONALE, a tool-implemented in Quintus Prolog- that ties together the processes of knowledge acquisition,expert system construction, and explanation of system reasoning. RATIONALE integrates explanations with reasoning by using domain knowledge together with explicitly represented strategies. Reasoning proceeds by constructing a hypothesis tree whose root contains the most general diagnosis of the expert system. Guided by a focusing algorithm, the tree branches into more specific hypotheses that explain the more detailed symptoms provided by the user. As the expert system is used, the hypothesis tree also serves as a dynamically generated explanation tree.<<ETX>>

Managing Mobility of Users in a Virtual Network

Terminal and personal mobility are the fundamental characteristics of Nomadic Computing. However, personal mobility provides a greater degree of flexibility, creating an environment in which a user roams in network without a wireless laptop or a mobile phone and yet enjoys anytime, anywhere network accessibility. This work presents NomadsPersonal Access System (NPAS): a software system at OSI application layer that provides a personal mobility environment within a virtual, private network, spanning different organizational networks. It implements dynamic association between a user and shared devices associated with a new location. The dynamic mapping of users to devices is achieved using InternetsLDAP distributed directory. The LDAPsdistributed directory provides services and location data to the network—thus incoming and outgoing messages can be easily routed to the current location of a nomad. The ability to know the current location of a nomad increases his/her accessibility to and from other people. Therefore, NPAS also addresses the messaging services and suggests a solution based on agents. This work is motivated by the larger project of the Mobile Agents Alliance, a collaborative effort that includes the National Research Council of Canada, the University of Ottawa, and Mitel Corporation.

A multi-agent testbed and an agent launch tool for diverse seamless personal information networking applications

This paper describes the design and implementation of a unique cooperative agents testbed and tool for launching cooperative agents in an environment that addresses diverse applications for the difficult problem of seamless personal information networking (SPIN). The real-world SPIN testbed is aimed at two difficult applications, namely seamless messaging and intelligent network management. Both applications are agent-driven and share agent behaviours and the messaging agents rely on the network management device diagnostic agents for input. The paper introduces both problem areas in a common testbed. The agent launch tool is described in detail. User-centric seamless messaging assumes heterogeneous communication environments intended to support todayis nomadic users. The prototype is introduced for the management of messages across distributed information networks. The aim of it is to intercept, filter, interpret, and deliver multi- modal messages be they voice, fax, video and/or e-mail messages. A useris Personal Communication Agent is charged with delivering messages to the recipient regardless of their target messaging device be it a telephone, a pager, a desktop, a wireless laptop or a wireless phone. Personal Communication Agents classify and act on incoming messages based on their content. A Secretary Agent routes and tailors urgent messages appropriately to the Device Manager Agent which delivers the message to a device that the user may be roaming or active on. What makes the Seamless Messaging Application unique is its approach to treating a message in a universal manner, its ability to mediate between different messaging environments and devices, and its ability to try to track and find the user.