Title: A System for Reasoning with Nonconvex Intervals
Author(s): M. Almeida
Title: Symbolic representation of user-defined time granularities
Author(s): Claudio Bettini, Roberto De Sibi
E-mail(s): bettini@dsi.unimi.it, rdesibi@it.oracle.com
Abstract: A recent effort has been done in
the literature to formally characterize the notion of
time granularity and the relationships between granularities, in
order to have a common framework for their specification
and to allow the interoperability of systems adopting
different time granularities.
This paper considers the mathematical characterization of finite and
periodical time granularities,
and it identifies a user-friendly
symbolic formalism which captures exactly that class of granularities.
This is achieved by a formal analysis
of the expressiveness of well-known symbolic representation formalisms.
Title: A Constraint-Based Specification of Periodic Patterns in Time-Oriented Data
Author(s): Shubha Chakravarty and Yuval Shahar
E-mail(s): {schakrav, shahar}@smi.stanford.edu
Abstract:
We use a constraint-based language to specify periodic temporal patterns. The Constraint-based Pattern Specification Language (CAPSUL) is simple to use, but allows a wide variety of patterns to be expressed. CAPSUL solves problems such as (1) how to use calendar-based constraints to define repetition of a periodic event, (2) what temporal relations must exist between consecutive repeats of a pattern, and (3) how expressivity is limited if the same temporal relations must hold between each pair of intervals in the pattern. We implemented CAPSUL in a temporal-abstraction system called Résumé, and used it in a graphical knowledge-acquisition tool to acquire domain-specific knowledge from experts about patterns to be found in large databases. We summarize the results of preliminary experiments using the pattern-specification and pattern-detection tools on data about patients who have cancer and have been seen at the University of Chicago bone-marrow-transplantation center.
Title: A Geometric Framework for Specifying Spatiotemporal Objects
Author(s): Jan Chomicki, Peter Z. Revesz
E-mail(s): chomicki@monmouth.edu, revesz@cse.unl.edu
Abstract: We present a framework for specifying spatiotemporal objects
using spatial and temporal objects, and geometric transformations.
We define a number of classes of spatiotemporal objects and study
their closure properties.
Title: TALplanner: An Empirical Investigation of a Temporal Logic-based Forward
Chaining Planner
Author(s): P. Doherty, J.Kvarnström
Title: A Graph-Theoretic Approach to
Efficiently Reason about Partially Ordered Events in the Event Calculus
Author(s): M. Franceschet, A. Montanari
Title:
Generating Scenarios for Periodic Events with Binary Constraints
Authors:
Lina Khatib and Robert A. Morris
E-mail(s):
{lina,morris}@cs.fit.edu
Abstract:
Reasoning with repeating events differs from reasoning about single
events primarily in the fact that with the former the available
information about aspects such as the number and period of the events
may be indefinite. Much useful knowledge about repeating events takes
the form of relationships between "successive" occurrences of the same
event, or "proximate" occurrences of pairs of repeating events. The
formulation presented here focuses on such knowledge. A backtracking
algorithm for solving reasoning problems involving repeating events is
presented and its complexity evaluated.
Title:
A Temporal Object-Oriented Data Model with Multiple Granularities
Author(s):
Isabella Merlo,
Elisa Bertino,
Elena Ferrari,
Giovanna Guerrini,
E-mail(s):
merloisa@disi.unige.it,
guerrini@disi.unige.it,
bertino@dsi.unimi.it,
ferrarie@dsi.unimi.it
Abstract:
In this paper we investigate some
issues arising from the introduction of multiple temporal granularities
in an object-oriented data model.
Although issues
concerning temporal granularities have been investigated in the context
of temporal relational database systems, no comparable amount of work
has been done in the context of the object-oriented model.
Moreover, the main drawback of the existing proposals
is the lack of
a formal basis -- which we believe is essential to manage the inherent
complexity of the object-oriented data model.
In this paper, we provide a complete temporal object-oriented type
system
supporting multiple temporal granularities and we formally define the
set
of legal values for our type system. We then address issues related
to inheritance, type refinement and substitutability.
Title:
Optimization in Constraint Reasoning about Repeating Events
Author(s):
Robert A. Morris and Lina Khatib
E-mail(s):
{morris,lina}@cs.fit.edu
Abstract:
The effective manipulation of temporal information about periodic events
is required for solving complex problems such as long range scheduling
or querying temporal information. Further more, many problems involving
repeating events require the optimization of temporal aspects of these
events, e.g., minimizing makespan in job-shop scheduling. This paper
contains a framework for representing and solving reasoning problems
in which temporal aspects of repeating events are to be optimized. This
framework rests upon three foundations: recent work on the characterization
of repeating events, the temporal CSP framework for processing constraints,
and the semiring generalization of CSPs. The semiring allows values to be
associated with consistent solutions generated from the specification;
the values are computed from functions that provide interpretations of
the optimizing constraints.
Title: Study and Comparison of Schema Versioning and Database
Conversion Techniques for Bi-temporal Databases
Author(s): Han-Chieh Wei, Ramez Elmasri
E-mail(s): wei@cse.uta.edu, elmasri@cse.uta.edu
Abstract: Schema evolution and schema versioning are two techniques
used for managing database evolution. Schema evolution keeps only the
current version of a schema and database after applying schema changes.
Schema versioning creates new schema versions and converts the corresponding
data while preserving the old schema versions and data. To provide the most
generality, bi-temporal databases can be used to realized schema versioning,
since they allow both retroactive and proactive updates to the schema and
database. In this paper we first study two proposed database conversion
approaches for supporting schema evolution and schema versioning: single
table version approach and multiple table version approach. We then propose
the partial table version approach to solve the problems encountered in these
approaches when applied to bi-temporal databases.
Author(s): H.Bowman, G.Faconti
Short Papers
Title: Using Interval
Temporal Logic to Model Cognitive Behaviour