Knowledge Engineering This file is under construction.
Abstract
A formal approach to modelling and specifying complex dynamic tasks is
introduced. A basic assumption is that complex (reasoning) tasks can be
modelled by a compositional architecture wherein components correspond to
tasks. Explicitation of the control of a system's problem solving behaviour is
essential when modelling complex reasoning tasks. The semantics of the task
models and problem solving methods involved is a description of a
compositional system's behaviour, and a temporal approach provides a means
to describe the dynamics involved. Temporal models are used to formalise
this semantics. The compositional structure of information states, transitions
and reasoning traces provides a transparant model of the system's behaviour,
both conceptually and formally.
Abstract
It is shown how specification of behavioural requirements from informal to formal can be integrated within knowledge engineering. The integration of requirements specification has addressed, in particular: the integration of requirements acquisition and specification with ontology acquisition and specification, the relations between requirements specifications and specifications of task models and problem solving methods, and the relation of requirements specification to verification.
Abstract
In current literature few detailed process models for Requirements Engineering are presented: usually high-level activities are distinguished, without a more precise specification of each activity. In this paper the process of Requirements Engineering has been analyzed using knowledge-level modelling techniques, resulting in a well-specified compositional process model for the Requirements Engineering task.
Abstract
A compositional generic process control model is presented which has been applied to control enzymatic biochemical processes. The model has been designed at a conceptual and formal level using the compositional development method DESIRE, and includes processes for analysis, planning and simulation. It integrates qualitative and quantitative techniques. Its application to enzymatic chemical processes is described.
Abstract
In this paper, graphical, conceptual graph-based representations for knowledge structures in the compositional development method DESIRE for knowledge-based and multi-agent systems are presented, together with a graphical editor based on the Constraint Graph environment. Moreover, a translator is described which translates these graphical representations to textual representations in DESIRE. The strength of the combined environment is a powerful -- yet easy-to-use -- framework to support the development of knowledge based and multi-agent systems. Finally, a mapping is presented from DESIRE, that is based on order sorted predicate logic, to Conceptual Graphs.
Abstract
In this paper a knowledge-based decision support system is described that
determines the abiotic (chemical and physical) characteristics of a site on the
basis of in-homogeneous samples of plant species. Techniques from the area
of non-monotonic reasoning were applied to model multi-interpretable input
information.
Abstract
In this paper logical techniques that were developed to formalize the analysis
of multi-interpretable information, such as belief set operators and selection
operators, are applied to an ecological domain. A knowledge-based decision
support system has been developed that determines the abiotic (chemical and
physical) characteristics of a site on the basis of inhomogeneous samples of
plant species that are observed. In this paper the logical foundation of this
system is described in terms of a belief set operator and a selection operator.
Moreover, it is shown how the belief set operator that corresponds to the
system can be specified by a normal default theory.
Abstract
In many areas development methods have been developed in a conceptual
design of complex systems is specified before systems are implemented. Such
specifications focus on the semantics of systems abstracting from
implementation details, providing a basis for verification and validation of the
functionality of the systems. A dedicated development method for multi-agent
systems, requires adequate means to describe the characteristics of multi-agent
systems, in particular, the control of the dynamics of (concurrent) reasoning
behaviour and acting behaviour (e.g., guided reasoning, observation,
communication and execution of actions). A compositional multi-agent system
development method based on the principles described in this paper can
provide support to multi-agent system designers during the entire design
process: process and knowledge abstraction, compositionality, reuse,
semantics and formal analysis with respect to verification and validation. One
specific compositional multi-agent development method is DESIRE (DEsign
and Specification of Interacting REasoning components). Although the paper
addreses the principles of compositional multi-agent system development
from a generic perspective, some of the examples used to illustrate the notions
discussed are taken from this compositional development method.
Abstract
Abilities of agents and properties of their environment provide a means to
describe behaviour and functionality. These abilities also provide a basis for
re-design. In this paper an example is given of a prototype system for re-
design of a multi-agent system in which the abilities and properties are made
explicit.
Abstract
In interactive design processes, strategic decisions are made at different
levels. To support designers, design support systems need to include
corresponding strategic knowledge at these levels. In this paper, three levels
of strategic interaction and strategic knowledge are identified within a
compositional model of design. These levels are identified in reasoning about
the manipulation of requirements and their qualifications, reasoning about the
manipulation of design object descriptions and reasoning about design
process co-ordination.
Abstract
This paper addresses management of conflicts in an agent by means
of reflective reasoning. A structure for reflective agents is proposed
within which reasoning about observation, assumption making and
communication; an agent's own information state and reasoning processes;
other agents' information states and reasoning processes, and combinations
of these types of reflective reasoning are explicitly modelled. The types
of knowledge needed to detect, analyse and resolve conflicts that arise by
meta-reasoning within the agent are discussed. The knowledge and
interaction between agents required to model the wise men's puzzle is used to
illustrate the approach.
Abstract
In this paper, graphical representations for knowledge structures in DESIRE
are presented, together with a graphical editor based on the Constraint Graph
environment. Moreover, a translator will be described which translates these
graphical representations to textual representations in DESIRE. The strength
of the combined environment is a powerful -- yet easy-to-use -- framework to
support the development of knowledge based and multi-agent systems.
Abstract
A generic broker agent architecture is introduced, designed in a principled
manner using the compositional development method for multi-agent systems
DESIRE. A flexible, easily adaptable agent architecture results in which, in
addition, facilities have been integrated that provide automated support of the
agent's own maintenance. Therefore, the agent is not only easily adaptable,
but it shows adaptive behaviour to meet new requirements, either in reaction
to communication with a maintenance agent, or in a fully autonomous
manner. Based on this architecture, applications are being developed in
Electronic Commerce, in co-operation with the Internet application company
Crisp, and in intelligent Web-sites, in co-operation with the insurance
company Delta Lloyd and the software company Ordina Utopics.
Abstract
In this paper a reusable multi-agent architecture is presented for reasoning
tasks that are supported by a system that interacts with the user at two levels:
at the level of the reasoning process itself and at the level of clarification of the
process. The multi-agent architecture distmguishes three agents: a user, a
decision support agent and a clarification support agent. The user and the
decision support agent cooperate on the basis of a shared model of the
reasoning task; the user and the clarification support agent cooperate on the
basis of a shared model of the clarification task. Interaction between the user
and the decision support agent, between the user and the clarification support
agent, and between the decision support agent and the clarification agent are
made explicit in the model. The model has been made using the compositional
modelling framework DESIRE. In cooperation with and funded by chemical
industry, it has been applied to diagnosis of chemical processes.
Abstract
This paper discusses an example of the application of a high-level modelling
framework which supports both the specification and implementation of a
system's conceptual design. This framework, DESIRE (framework for
DEsign and Specification of Interacting REasoning components), explicitly
models the knowledge, interaction, and coordination of complex tasks and
reasoning capabilities in agent systems. For the application domain addressed
in this paper, an operational multi-agent system which manages an electricity
transportation network for a Spanish electricity utility, a comprehensible
specification is presented.
Abstract
In this paper a compositional verification method for models of knowledge-
based systems is introduced. Required properties of the system are formally
verified by deriving them from assumptions that themselves are properties of
sub-components, which in their turn may be derived from assumptions on
sub-sub-components, and so on. The method is based on properties that are
formalised in terms of temporal semantics; both static and dynamic properties
are covered. The compositional verification method imposes structure on the
verification process. By the possibility to focus at one level of abstraction
(information and process hiding), compositional verification provides
transparency and limits the complexity per level. Since verification proofs are
structured in a compositional manner, they can be reused in case of
modification of the system. The method is illustrated for a generic model for
diagnostic reasoning.
Abstract
It is a recent trend in the literature on verification to study the use of
compositionality and abstraction to structure the process of verification.
Earlier, a compositional verification method was introduced for logic-based
specifications of knowledge-based systems. The current paper discusses the
requirements for the choice and use of a suitable logic with which verification
proofs of such compositional reasoning systems can be formalized. For the
particular application of the logic the following requirements for the logic
itself and for the use of the logic are of importance:
- compositional structure: proofs can be structured in a compositional
manner, in accordance with the compositional structure of the system design.
- dynamics and time: dynamic properties can be expressed, reasoning and
induction over time is possible.
- incomplete information states can be expressed.
- transparency: the proof system and the semantics are transparent and not
unnecessarily complicated.
In the paper, temporal epistemic logic (TEL) is shown to be a suitable logic.
By choosing temporal epistemic logic, a choice was also made for a discrete
and linear time structure and for time to be global, which is a suitable choice
for the formalization of verification proofs of sequential knowledge-based
reasoning systems.
Abstract
This paper introduces a task model for redesign of compositional knowledge-
based systems based on a generic task model of design. A generic task model
of design provides an abstract description of a design task and a generic
structure which can be refined for design tasks in specific domains of
application. A generic task model of design, shown to incorporate redesign, is
presented and refined to a task model for redesign of compositional
knowledge-based systems. The applicability of this task model will be
illustrated for the redesign of a diagnostic knowledge-based system.
Abstract
An elevator configuration task, the VT task described for Sisyphus-2, is
modelled within DESIRE as a design task. DESIRE is a framework within
which complex reasoning tasks are modelled as compositional architectures.
Compositional architectures are based on a task composition, acquired during
task analysis. An earlier developed generic task model of design, based on a
logical analysis and synthesis of task models devised for diverse applications,
has been specialised and instantiated for the elevator configuration task. The
resulting task model includes a description of (relevant parts of) the ontology
of the elevator domain and a description of the problem solving method.
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Abstract
The role of an agreed, shared task model as an intermediate representation of a
design/decision task upon which (1) negotiation between an expert user and a
knowledge engineer, and (2) interaction between an expert user and an
intelligent design/decision support system are based, is the focus of the
research presented. A declarative compositional approach to user-centered
system design (within the DESIRE framework) is presented and illustrated on
the basis of a shared task model for the design of environmental policy.