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Temporal Representation and Reasoning, 1997. (TIME '97), Proceedings., Fourth International Workshop on

Date 10-11 May 1997

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  • Proceedings of TIME '97: 4th International Workshop on Temporal Representation and Reasoning

    Publication Year: 1997
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    Freely Available from IEEE
  • Index of authors

    Publication Year: 1997, Page(s): 187
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    Freely Available from IEEE
  • Contextual logic of change and contextual proofs

    Publication Year: 1997, Page(s):153 - 159
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (632 KB)

    We discuss CLOC, an alternative approach to reasoning about action and change, which is neither based in the Situation Calculus nor in Circumscription. In our approach, inspired by the Possible Worlds Approach, change is modeled as changing the theory that models the world. We extended First Order Logic, in order to be able to represent elementary and structured changes, and define predicates rela... View full abstract»

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  • Concurrency control for perceivedly instantaneous transactions in valid-time databases

    Publication Year: 1997, Page(s):112 - 118
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    Although temporal databases have received considerable attention as a topic for research, little work in the area has paid attention to the concurrency control mechanisms that might be employed in temporal databases. This paper describes how the notion of the current time-also called `now'-in valid-time databases can cause standard serialisation theory to give what are at least unintuitive results... View full abstract»

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  • Practical temporal reasoning for real scheduling applications

    Publication Year: 1997
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (52 KB)

    Summary form only given. Presents a set of requirements for modelling and solving scheduling problems, including a somewhat unconventional definition of the term “solution”. These requirements, distilled from experience implementing and fielding scheduling systems in a wide variety of domains, strongly constrain the nature of a useful scheduling system. Using a set of example problems ... View full abstract»

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  • Knowledge-based temporal interpolation

    Publication Year: 1997, Page(s):102 - 111
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (928 KB)

    Temporal interpolation is the task of bridging gaps between time-oriented concepts in a context-sensitive manner. It is a subtask important for solving the temporal-abstraction task-abstraction of interval-based, higher-level concepts from time-stamped data. We present a knowledge-based approach to the temporal-interpolation task and discuss in detail the precise knowledge required by that approac... View full abstract»

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  • Bidirectional inference in probabilistic temporal reasoning

    Publication Year: 1997, Page(s):31 - 37
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    Belief update based on observations is a fundamental problem in AI. We propose a belief update strategy suitable for temporal probabilistic domains. We assume that the causal structure of the world is specified in probabilistic terms. The causal specifications are used to perform two basic operations: explanation (backward propagation) and projection (forward propagation). We show that probabilist... View full abstract»

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  • A resolution method for CTL branching-time temporal logic

    Publication Year: 1997, Page(s):20 - 27
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    We extend our clausal resolution method for linear temporal logics to a branching-time framework. The branching-time temporal logics considered are computation tree logic (CTL), often regarded as the simplest useful logic of this class, and extended CTL (ECTL), which is CTL extended with fairness operators. The key elements of the resolution method, namely the normal form, the concept of step reso... View full abstract»

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  • Enhancements to the Ground Processing Scheduling System

    Publication Year: 1997, Page(s):72 - 77
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    This paper describes work in progress to enhance the performance of the Ground Processing Scheduling System (GPSS). The GPSS is a constraint-based scheduler that deals with three kinds of constraints: temporal, resource, and configuration. It starts with a complete schedule that may have some constraint violations (conflicts) and gradually improves the schedule by reducing the violations. The obje... View full abstract»

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  • Modal event calculi with preconditions

    Publication Year: 1997, Page(s):38 - 45
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    Kowalski and Sergot's (1986) event calculus (EC) is a simple temporal formalism that, given a set of event occurrences, allows the derivation of the maximal validity intervals (MVIs) over which properties initiated or terminated by those events hold. The limited expressive power of EC is notably augmented by permitting events to initiate or terminate a property only if a given set of preconditions... View full abstract»

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  • Representing temporal relationships between events and their effects

    Publication Year: 1997, Page(s):148 - 152
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    Temporal relationships between events and their effects are complex. As the effects of a given event, a proposition may change its truth value immediately after the occurrence of the event and remain true until some other events occur, while another proposition may only become true/false from some time after the causal event has occurred. Expressing delayed effects of events has been a problematic... View full abstract»

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  • A hierarchy for convex relations

    Publication Year: 1997, Page(s):86 - 93
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper is concerned with a hierarchical representation of the convex relation algebra, which is a computationally tractable subset of Allen's interval calculus. The hierarchy of convex relations is used to determine the minimal point relation constraints which hold between the end points of the intervals. Nine convex relations are proven to be special, because they introduce new constraints. O... View full abstract»

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  • GCH-OSQL: a temporally-oriented object-oriented query language based on a three-valued logic

    Publication Year: 1997, Page(s):119 - 126
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (788 KB)

    The need of managing temporal information given at different levels of granularity and indeterminacy is common to many application areas. Between them, we focus on the management of clinical data. Different time granularities are also needed in querying temporal databases. In this paper, we describe GCH-OSQL (Granular Clinical History-Object Structured Query Language), an object-oriented temporall... View full abstract»

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  • On effective data clustering in bitemporal databases

    Publication Year: 1997, Page(s):54 - 61
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    Temporal databases provide built-in supports for efficient recording and querying of time-evolving data. In this paper, data clustering issues in temporal database environment are addressed. Data clustering is one of the most effective techniques that can improve performance of a database system. However, data clustering methods for conventional databases do not perform well in temporal databases ... View full abstract»

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  • An efficient algorithm for temporal abduction

    Publication Year: 1997, Page(s):28 - 30
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    Abduction is the process of generating explanations for an observation, starting from a domain theory. We consider an extension of the classical definition of abduction in order to deal with temporal knowledge both in the theory and in the observations. This form of abduction is the basis of many problem solving activities such as temporal diagnosis and reasoning about actions and events. We show ... View full abstract»

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  • Contingent durations in temporal CSPs: from consistency to controllabilities

    Publication Year: 1997, Page(s):78 - 85
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (692 KB)

    Temporal Constraint Networks (TCSP) allow to express minimal and maximal durations between time-points. Though being used in many research areas, this model disregards the contingent nature of some constraints, whose effective duration cannot be decided by the system but is provided by the external world. We propose an extension of TCSP in which the classical network consistency property must be r... View full abstract»

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  • BCTL: a branching clock temporal logic

    Publication Year: 1997, Page(s):140 - 147
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB)

    This paper presents a branching time temporal logic called BCTL. In this logic, branching time is represented by branching clocks, which can be specified as Chronolog programs. In BCTL, formulas are allowed to be defined on different branching clocks. Apart from the temporal operators first and next, BCTL contains a next-bounded symbol ! and four modalities: ∀□, ∀?, ∃&sq... View full abstract»

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  • Qualitative and quantitative temporal constraints about numerically quantified periodic events

    Publication Year: 1997, Page(s):94 - 101
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (780 KB)

    The paper describes an integrated temporal formalism which deals with (i) quantitative information about the frame of time and the user-defined calendar-dates (periods) in which periodic events are located, (ii) (possibly multiple) numeric quantifiers indicating the number of repetitions of events and (iii) qualitative relations between periodic events. The paper defines the operations of intersec... View full abstract»

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  • Visual query operators for temporal databases

    Publication Year: 1997, Page(s):46 - 53
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (732 KB)

    Many recent proposals in the literature present easy-to-use query languages, based on visual representations of the database and direct manipulation mechanisms. Such proposals essentially deal with conventional query operations, whereas little effort is devoted to investigate friendly environments for querying temporal databases. Nevertheless, temporal aspects are generally considered extremely re... View full abstract»

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  • Alternative conceptions of the time-line

    Publication Year: 1997
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (20 KB)

    Summary form only given. It is often assumed that if time is continuous, then the standard mathematical account of the continuum, the real line, is the appropriate model of the local structure of the timeline. However, another popular account of the timeline which provides the basis for Allen's famous 13 interval relations does not seem naturally compatible with the real line. This paper sharpens ... View full abstract»

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  • Entities and relations for historical relational databases

    Publication Year: 1997, Page(s):180 - 186
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB)

    Research to extend models of data to handle the temporal dimension has been conducted mainly in the context of the relational data model. In the relational model, the primary object of database design, manipulation and retrieval is the relation, viewed extensionally as a finite set of tuples. This paper proposes three useful types of temporal entities: events, histories, and valid-time relations, ... View full abstract»

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  • Temporal control structures in expert critiquing systems

    Publication Year: 1997, Page(s):160 - 167
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (600 KB)

    Critiquing in time critical and resource constrained domains requires special control structures that allow the expert critiquing system to compare user actions with that of its own. This is necessitated by the fact that the priorities of actions in such domains change over time and the system needs to be robust enough to reflect this in its critiques. This paper describes a model of expert critiq... View full abstract»

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  • Time in a multi-theory logical framework

    Publication Year: 1997, Page(s):62 - 68
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    We present a knowledge representation framework where a collection of logic programs can be combined together by means of meta-level program composition operations. Each object-level program is composed by a collection of extended clauses, equipped with a time interval representing the time period in which they hold. The interaction between program composition operations and time yields a powerful... View full abstract»

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  • Similarity of event sequences

    Publication Year: 1997, Page(s):136 - 139
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    Sequences of events are an important form of data that occurs in many application domains, such as telecommunications, biostatistics, user interface design, etc. We present a simple model for measuring the similarity of event sequences, and show that the resulting measure of distance can be efficiently computed using a form of dynamic programming View full abstract»

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  • Automata representations for Concurrent METATEM

    Publication Year: 1997, Page(s):12 - 19
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (596 KB)

    Concurrent METATEM is a language based on the execution of temporal logic formulae. The current implementations are based upon direct interpretation, yet are too slow for large applications. We present an approach to implementing the language by representing temporal formulae as finite-state automata. To combat the problems associated with constructing a single automaton containing all possible mo... View full abstract»

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