Time and Temporal Reasoning
- Guido Boella, Guido Governatori, Joris Hulstijn,
Régis Riveret, Antonino Rotolo, and Leendert van der Torre.
-
Time and
defeasibility in FIPA ACL semantics.
In 2008 IEEE/WIC/ACM International Conference on Web Intelligence and
Intelligent Agent Technology, pages 634-637. IEEE Press,
2008, Copyright ©
2008 IEEE.
Abstract: Inferences about communicative actions are often
conditional, non-monotonic, and involve the issue of time. Most agent
communication languages, however, ignore these issues, due to the difficulty
to combine them in a single formalism. This paper addresses such issues in
defeasible logic, and illustrates how to express a semantics for ACLs in
order to make non-monotonic inferences on the basis of communicative actions.
 
- Guido Governatori.
-
A
logic framework of normative-based contract management.
In Satoshi Tojo, editor, Fourth International Workshop on
Juris-informatics (JURISIN 2010), November 18-19 2010.
Abstract: In this paper an extended Defeasible Logic framework is
presented to do the representation and reasoning work for the normative-based
contract management. A simple case based on FIDIC is followed as the usage
example. This paper is based on the idea that normative concepts and
normative rules should play the decisive roles in the normative-based
contract management. Those normative concepts and rules are based on the
normative literals and operators like action, obligation, permission and
violation. The normative reduction is based on the normative concepts,
normative connections and normative rules, especially on the superiority
relation over the defeasible rules.
 
-
Guido Boella, Guido Governatori, Joris Hulstijn, Régis Riveret, Antonino Rotolo and Leemndert van der Torre.
-
FIPA Communicative Acts in Defeasible Logic.
In Alankar Karol, Pavlos Peppas and Mary-Anne Williams, editor,
Seventh IJCAI International Workshop on Nonmonotonic Reasoning,
Action and Change (NRAC'07), Hyderabad, India, 7-8 January, 2007.
Abstract: In agent communication languages, the inferences
that can be made on the basis of a communicative action are inherently
conditional, and non-monotonic. For example, a proposal only leads to
a commitment, on the condition that it is accepted. And in a
persuasion dialogue, assertions may later be retracted. In this paper
we therefore present a defeasible logic that can be used to express a
semantics for agent communication languages, and to efficiently make
inferences on the basis of communicative actions. The logic is
non-monotonic, allows nested rules and mental attitudes as the content
of communicative actions, and has an explicit way of expressing
persistence over time. Moreover, it expresses that mental attitudes
are publicly attributed to agents playing roles in the dialogue. To
illustrate the usefulness of the logic, we reformalize the meta-theory
underlying the FIPA semantics for agent communication, focusing on
inform and propose. We show how composed speech acts can be
formalized, and extend the semantics with an account of persuasion.
- Guido Governatori, Joris Hulstijn, Régis
Riveret, and Antonino Rotolo.
-
Characterising deadlines in temporal modal defeasible logic.
In Mehmet A. Orgun and John Thornton, editors, 20th Australian Joint
Conference on Artificial Intelligence, AI 2007,
LNAI 4830, pages 486-496. Springer, 2007.
Copyright © 2007 Springer.
Abstract: We provide a conceptual analysis of several kinds of
deadlines, represented in Temporal Modal Defeasible Logic. The paper presents
a typology of deadlines, based on the following parameters: deontic operator,
maintenance or achievement, presence or absence of sanctions, and persistence
after the deadline. The deadline types are illustrated by a set of examples.
- Guido Governatori, Mehmet A. Orgun, and Chuchang
Liu.
-
Modal tableaux for verifying stream authentication protocols.
Journal of Autonomous Agents and Multi Agent Systems,
2008., Copyright © 2008
Springer.
Abstract: To develop theories to specify and reason about various
aspects of multi-agent systems, many researchers have proposed the use of
modal logics such as belief logics, logics of knowledge, and logics of norms.
As multi-agent systems operate in dynamic environments, there is also a need
to model the evolution of multi-agent systems through time. In order to
introduce a temporal dimension to a belief logic, we combine it with a
linear-time temporal logic using a powerful technique called fibring for
combining logics. We describe a labelled modal tableaux system for the
resulting fibred belief logic (FL) which can be used to automatically verify
correctness of inter-agent stream authentication protocols. With the
resulting fibred belief logic and its associated modal tableaux, one is able
to build theories of trust for the description of, and reasoning about,
multi-agent systems operating in dynamic environments.
- Guido Governatori, Vineet Padmanabhan and
Rotolo. Antonino.
-
Rule-Based Agents in Temporalised Defeasible Logic. In Qiang Yang
and Geoff Webb, editor, Ninth Pacific Rim International
Conference on Artificial Intelligence, Guilin, 7-11 August.
pages 31-40. LNAI 4099. Springer, Berlin, 2006. The original
publication is available atwww.springerlink.com
Abstract: This paper provides a framework based on temporal
defeasible logic to reason about deliberative rule-based cognitive
agents. Compared to previous works in this area our framework has the
advantage that it can reason about temporal rules. We show that for
rule-based cognitive agents deliberation is more than just deriving
conclusions in terms of their mental components. Our paper is an
extension of ai05,lpar05 in the area of cognitive agent programming
- Guido Governatori and Antonino Rotolo.
-
Changing
legal systems: Abrogation and annulment. Part I: Revision of defeasible
theories.
In Ron van der Meyden and Leon van der Torre, editors, 9th International
Conference on Deontic Logic in Computer Science (DEON2008), Lecture
Notes in Computer Science. Springer, 2008.
Copyright © 2008 Springer.
Abstract: In this paper we investigate how to model legal
abrogation and annulment in Defeasible Logic. We examine some options that
embed in this setting, and similar rule-based systems, ideas from belief and
base revision. In both cases, our conclusion is negative, which suggests to
adopt a different logical model.
- Guido Governatori and Antonino Rotolo.
-
Changing
legal systems: Abrogation and annulment. Part II: Temporalised defeasible
logic.
In Guido Boella, Harko Verhagen, and Muindhar Singh, editors, Proceedings
of Normative Multi Agent Systems (NorMAS 2008, Luxembourg 15-16 July 2008.
Abstract: In this paper we propose a temporal extension of
Defeasible Logic to model legal modifications, such as abrogation and
annulment. Hence, this framework overcomes the difficulty, discussed
elsewhere \cite{deon-part1}, of capturing these modification types using
belief and base revision.
 
- Guido Governatori and Antonino Rotolo.
-
On the complexity of temporal defeasible logic.
In Thomas Meyer and Eugenia Ternovska, editors, 13 International Workshop
on Non-Monotonic Reasoning (NMR 2010), CEUR Workshop Proceedings, 2010.
Abstract: In this paper we investigate the complexity of temporal
defeasible logic, and we propose an efficient algorithm to compute the
extension of a temporalised defeasible theory. We motivate the logic showing
how it can be used to model deadlines.
 
- Guido Governatori and Rotolo Antonino.
-
Justice delayed is
justice denied: Logics for a temporal account of reparations and legal
compliance.
In João Leite, Paolo Torroni, Thomas Ågotnes, Guido Boella, and Leon van der Torre, editors, CLIMA XII, 12th International Workshop on
Computational Logic and Multi-Agent Sytems, number LNCS. Springer, 2011,
Copyrigth © 2011 Springer.
Abstract: In this paper we extend the logic of violation proposed
by Governatori and Rotolo with time, more precisely, we temporalise that
logic. The resulting system allows us to capture many subtleties of the
concept of legal compliance. In particular, the formal characterisation of
compliance can handle different types of legal obligation and different
temporal constraints over them. The logic is also able to represent, and
reason about, chains of reparative obligations, since in many cases the
fulfillment of these types of obligation still amount to legally acceptable
situations.
 
-
Guido Governatori, Antonino Rotolo, Régis Riveret, Monica Palmirani and Giovanni Sartor.
-
Variations of Temporal Defeasible Logic for Modelling Norm Modifications.
In Radboud Winkels, editor,
Proceedings of 11th International Conference on Artificial Intelligence and Law,
pp. 155-159. ACM Press, New York, 2007. Copyright © 2007 ACM
Abstract: This paper proposes some variantsts of Temporal
Defeasible Logic (TDL) to reason about normative modifications. These
variants make it possible to differentiate cases in which, for example,
modifications at some time change legal rules but their conclusions
persist afterwards from cases where also their conclusions are blocked.
- Guido Governatori, Antonino Rotolo, and Rossella
Rubino.
-
Implementing temporal defeasible logic for modeling legal reasoning.
In 3rd Juris-Informatics Workshop (Jurisin 2009), LNAI, Berlin,
2010. Springer, Copyright © 2010 Springer.
Abstract: In this paper we briefly present an efficient
implementation of temporal defeasible logic, and we argue that it can be used
to efficiently capture the the legal concepts of persistence, retroactivity
and periodicity. In particular, we illustrate how the system works with a
real life example of a regulation.
 
- Guido Governatori, Antonino Rotolo and Giovanni Sartor.
-
Temporalised Normative Positions in Defeasible Logic.
In Anne Gardner, editor,
10th International Conference on Artificial Intelligence and Law
(ICAIL05), Bologna, June 6-11, pages 25-34. ACM Press, 2005.
Copyright ©
ACM Press
Abstract: We propose a computationally oriented non-monotonic
multi-modal logic arising from the combination of temporalised agency
and temporalised normative positions. We argue about the defeasible
nature of these notions and then we show how to represent and reason
with them in the setting of Defeasible Logic.
- Guido Governatori and Paolo Terenziani.
- Temporal extensions to defeasible logic.
In Mehmet A. Orgun and John Thornton, editors, 20th Australian Joint
Conference on Artificial Intelligence, AI 2007,
LNAI 4830, pages 476-485. Springer, 2007.
Copyright © 2007 Springer.
Abstract: In this paper, we extend Defeasible Logic (a
computationally-oriented non-monotonic logic) in order to deal with
temporalised rules. In particular, we extend the logic to cope with durative
facts, as well as with delays between the antecedent and the consequent of
rules. We showed that the extended temporalised framework is suitable to
model different types of causal relations which have been identified by the
specialised literature. We also prove that the computational properties of
the original logic are still retained by the extended approach.
- Ruopeng Lu, Shazia Sadiq and Guido Governatori.
-
Utilizing Successful Work Practice for Business Process Evolution.
In Witold Abramowicz and Heinrich C. Mayr, editors,
Business Information Systems (BIS 2006),
Klagenfurt, Austria, May 31-June 2. pages 58-76.
LNI 85. GI, Berlin, 2006. Copyright © GI
Abstract: Business process management (BPM) has emerged as a
dominant technology in current enterprise systems and business
solutions. However, business processes are always evolving in current
dynamic business environments where requirements and goals are
constantly changing. Whereas literature reports on the importance of
domain experts in process modelling and adaptations, current solutions
have not addressed this issue effectively. In this paper, we present a
framework that utilizes successful work practice to support business
process evolution. The framework on one hand provides the ability to
use domain expert knowledge and experience to tailor individual
process instances according to case specific requirements; and on the
other, provides a means of using this knowledge through learning
techniques to guide subsequent process changes.
- Ruopeng Lu, Shazia Sadiq, and Guido Governatori.
-
On
managing business processes variants.
Data and Knowledge Engineering, 2009.
Abstract: Variance in business process execution can be the
result of several situations, such as disconnection between documented models
and business operations, workarounds in spite of process execution engines,
dynamic change and exception handling, flexible and ad-hoc requirements, and
collaborative and/or knowledge intensive work. It is imperative that
effective support for managing process variances be extended to organizations
mature in their BPM (Business Process Management) uptake so that they can
ensure organization wide consistency, promote reuse and capitalize on their
BPM investments. This paper presents an approach for managing business
processes that is conducive to dynamic change and the need for flexibility in
execution. The approach is based on the notion of process constraints. It
further provides a technique for effective utilization of the adaptations
manifested in process variants. In particular, we will present a facility for
discovery of preferred variants through effective search and retrieval based
on the notion of process similarity, where multiple aspects of the process
variants are compared according to specific query requirements. The advantage
of this approach is the ability to provide a quantitative measure for the
similarity between process variants, which further facilitates various BPM
activities such as process reuse, analysis and discovery.
 
- Ruopeng Lu, Shazia Sadiq, Guido Governatori, and
Xiaoping Yang.
-
Defining
adaptation constraints for business process variants.
In 12th International Conference on Business Information Systems,
Lecture Notes in Business Information Processing 7.
Springer, 2009, Copyright
© 2009 Springer.
Abstract: In current dynamic business environment, it has been
argued that certain characteristics of ad-hocism in business processes are
desirable. Such business processes typically have a very large number of
instances, where design decisions for each process instance may be made at
runtime. In these cases, predictability and repetitiveness cannot be counted
upon, as the complete process knowledge used to define the process model only
becomes available at the time after a specific process instance has been
instantiated. The basic premise is that for a class of business processes it
is possible to specify a small number of essential constraints at design
time, but allow for a large number of execution possibilities at runtime. The
objective of this paper is to conceptualise a set of constraints for process
adaptation at instance level. Based on a comprehensive modelling framework,
business requirements can be transformed to a set of minimal constraints, and
the support for specification of process constraints and techniques to ensure
constraint quality are developed.
 
- Ruopeng Lu, Shazia Sadiq, Vineet Padmanabhan
and Guido Governatori.
-
Using a Temporal Constraint Network for Business Process Execution.
In Gillian Dobbie and James Bailey, editor,
Seventeenth Australasian Database Conference (ADC2006),
Hobart, Australia, 16-19 January. pages 157-166. CRPIT.
ACS, Sydney, 2006.
Copyright © ACS
Abstract: Business process management (BPM) has emerged as a
dominant technology in current enterprise systems and business
solutions. However, the technology continues to face challenges in
coping with dynamic business environments where requirements and goals
are constantly changing. In this paper, we present a modelling
framework for business processes that is conducive to dynamic change
and the need for flexibility in execution. This framework is based on
the notion of process constraints. Process constraints may be
specified for any aspect of the process, such as task selection,
control flow, resource allocation, etc. Our focus in this paper is on
a set of scheduling constraints that are specified through a temporal
constraint network. We will demonstrate how this specification can
lead to increased flexibility in process execution, while maintaining
a desired level of control. A key feature and strength of the approach
is to use the power of constraints, while still preserving the
intuition and visual appeal of graphical languages for process
modelling.
- Mehmet A. Orgun, Guido Governatori
and Chuchang Liu.
-
Modal Tableaux for Verifying Security Protocols.
In Barbara Dunin-Keplicz and Rineke Verbrugge, editor,
Formal Approaches to Multi-Agent Systems (FAMAS 2006),
Riva del Garda, Italy, 28 August - 1 September.
pages 31-46. 2006.
Abstract: To develop theories to specify and reason about
various aspects of multi-agent systems, many researchers have proposed
the use of modal logics such as belief logics, logics of knowledge,
and logics of norms. As multi-agent systems operate in dynamic
environments, there is also a need to model the evolution of
multi-agent systems through time. In order to introduce a temporal
dimension to a belief logic, we combine it with a linear-time temporal
logic using a powerful technique called fibring for combining
logics. We describe a labelled modal tableaux system for a fibred
belief logic (FL) which can be used to automatically verify
correctness of inter-agent stream authentication protocols. With the
resulting fibred belief logic and its associated modal tableaux, one
is able to build theories of trust for the description of, and
reasoning about, multi-agent systems operating in dynamic
environments.
- Mehmet A. Orgun, Ji Ma,
Chuchang Liu and Guido Governatori.
-
Analysing Stream Authentication Protocols in Autonomous Agent-Based Systems.
In 2nd IEEE International Symposium on Dependable, Autonomic and
Secure Computing (DASC'06),
Indiana University, Purdue University, Indianapolis, USA, September
29--October 1. pages 325-332. IEEE Press, Los Alamitos, 2006.
Copyright © IEEE Press
Abstract: In stream authentication protocols used for
large-scale data dissemination in autonomuous systems,
authentication is based on the timing of the publication of keys,
and depends on trust of the receiver in the sender and belief on
whether an intruder can have prior knowledge of a key before it is
published by a protocol. Many existing logics and approaches have
successfully been applied to specify other types of authentication
protocols, but most of them are not appropriate for analysing stream
authentication protocols. We therefore consider a fibred modal logic
that combines a belief logic with a linear-time temporal logic which
can be used to analyse time-varying aspects of certain
problems. With this logical system one is able to build theories of
trust for analysing stream authentication protocols, which can deal
with not only agent beliefs but also the timing properties of an
autonomous agent-based system.
- Régis Riveret, Guido Governatori and
Antonino Rotolo.
-
Argumentation Semantics for Temporal Defeasible Logic.
In Loris Penserini, Pavlos Peppas and Anna Perini, editor,
Third European Starting AI Researcher Symposium (STAIRS 2006),
Riva del Garda, 28-29 August. pages 267-268.
Frontiers in Artificial Intelligence and Applications 142.
IOS Press, Amsterdam, 2006.
Abstract: We present an extension of the argumentation
semantics for defeasible logic to cover the temporalisation of
defeasible logic with permanent and immanent temporal literals
-
Régis Riveret, Antonino Rotolo and Guido Governatori.
-
Interaction between Normative Systems and Cognitive agents in
Temporal Modal Defeasible Logic. In Guido Boella, Leon van der
Torre and Harko Verhagen, editors, Normative Multi-agent
Systems. Dagstuhl Seminar Proceedings 7122. Internationales
Begegnungs- und Forschungszentrum fuer Informatik (IBFI), Schloss
Dagstuhl, Germany, Dagstuhl, Germany, 2007.
Abstract: While some recent frameworks on cognitive agents
addressed the combination of mental attitudes with deontic concepts,
they commonly ignore the representation of time. We propose in this
paper a variant of Temporal Modal Defeasible Logic to deal in
particular with temporal intervals.
 
- Insu Song and Guido Governatori.
-
Hardware Implementation of Temporal Nonmonotonic Logics.
In Abdul Sattar and Byeong Ho Kang, editor,
19th Australian Joint Conference on Artificial Intelligence,
Hobart, 4-8 December. pages 808-817. Lecture Notes in Computer Science 4304.
Springer, Berlin, 2006. The original publication is available at
www.springerlink.com
Abstract: In order to apply nonmonotonic logics for
specifying industrial automation controllers, we define (1) a method
to extend atemporal nonmonotonic logics with temporal operators and
(2) a mapping of these new temporal nonmonotonic logics into a
Metric Temporal Logic. This mapping provides a formal specification
method for real-time temporal reasoning digital circuits for the
temporal nonmonotonic logics. We present our method in the context
of synthesizing custom digital hardware (called agent chip)
automatically from high level agent specifications.
- Bela Stantic, Guido Governatori Abdul Sattar.
-
Handling of Current Time in Native XML Databases.
In Gillian Dobbie & James Bailey, editor,
Seventeenth Australasian Database Conference (ADC2006),
Hobart, Australia. pages 175-182. CRPIT. ACS, Sydney, 2006.
Copyright © 2006 ACS
Abstract: The introduction of Native XML databases opens many
research questions related to the data models used to represent and
manipulate data, including temporal data in XML. Increasing use of
XML for Valid Web pages warrants an adequate treatment of
now in Native XML databases. In this study, we examined how
to represent and manipulate now-relative temporal data. We
identify different approaches being used to represent current time
in XML temporal databases, and introduce the notion of storing
variables such as `now' or `UC' as strings in XML native
databases. All approaches are empirically evaluated on a query that
time-slices the timeline at the current time. The experimental
results indicate that the proposed extension offers several
advantages over other approaches: better semantics, less storage
space and better response time.
- Bela Stantic, Paolo Terenziani, Abdul Sattar, Alessio
Bottrighi, and Guido Governatori.
-
Towards an
implicit treatment of periodically-repeated medical data.
In Charles Safran, Shane Reti, and Heimar Marin, editors, MEDINFO 2010.
Proceedings of the 13th World Congress on Medical Informatics, pp. 1131-1135. Volume
160 of Studies in Health Technology and Informatics, Amsterdam,
2010. IOS Press, Copyrigth © 2010
IMIA and SAHIA.
Abstract: Temporal information plays a crucial role in medicine,
so that in Medical Informatics there is an increasing awareness that suitable
database approaches are needed to store and support it. Specifically, a great
amount of clinical data (e.g., therapeutic data) are periodically repeated.
Although an explicit treatment is possible in most cases, it causes severe
storage and disk I/O problems. In this paper, we propose an innovative
approach to cope with periodic medical data in an implicit way. We propose a
new data model, representing periodic data in a compact (implicit) way, which
is a consistent extension of TSQL2 consensus approach. Then, we identify some
important types of temporal queries, and present query answering algorithms
to answer them. We also sketch a temporal relational algebra for our
approach. Finally, we show experimentally that our approach outperforms
current explicit approaches.
 
- Monica Palmirani, Guido Governatori, and Contissa
Giuseppe.
-
Modelling
temporal legal rules.
In Tom van Engers, editor, Proceedings of the 13th International
Conference on Artificial Intelligence and Law (ICAIL 2011). ACM Press,
2011. Copyrigth © 2011 ACM Press.
Abstract: Legal reasoning involves multiple temporal dimensions
but the existing state of the art of legal representation languages does not
allow us to easily combine expressiveness, performance and legal reasoning
requirements. Moreover we also aim at the combination of legal temporal
reasoning with the defeasible logic approach, maintaining a computable
complexity. The contribution of this work is to extend LKIF-rules with
temporal dimensions and defeasible tools, extending our previous work.