NatureTime: Temporal Granularity in Simulation of Ecosystems

Journal of Experimental & Theoretical Artificial Intelligence, 2006

In many application areas, including planning, workflow, guideline and protocol management, the description of the domain involves composite and/or periodic events, mutually related by temporal constraints on the execution order. Such events represent 'classes', since they can be instantiated to specific executions of the plan, guideline etc., and each execution must 'respect' the temporal constraints imposed on the corresponding classes. The main objective of our work is that of proposing an approach dealing with the above-mentioned temporal phenomena. To achieve such an objective, we propose a tractable domain-independent temporal reasoner. This enhances the generality of our approach, which provides a domain-independent module which can be integrated with other software tools to solve temporal problems in specific domains.

Working Notes of the Workshop on Approximation and Abstraction of Computational Theories, AAAI-92, San Jose, CA, 1992

In this paper we consider the use of abstractions in temporal reasoning. We introduce two abstraction methods for temporal data: summarization and generalization. We show how they can reduce the complexity of resource allocation and rescheduling problems and thus support a decision making process. We also show how the use of such mechanisms can be extended to solve di cult problems in reasoning about physical phenomena.

A series of temporal reasoning tasks are identified which motivate the consideration and application of temporal logics in artificial intelligence. There follows a discussion of the broad issues involved in modelling time and constructing a temporal logic. The paper then presents a detailed review of the major approaches to temporal logics: first-order logic approaches, modal temporal logics and reified temporal logics. The review considers the most significant exemplars within the various approaches, including logics due to Russell, Hayes and McCarthy, Prior, McDermott, Allen, Kowalski and Sergot. The logics are compared and contrasted, particularly in their treatments of change and action, the roles they seek to fulfil and the underlying models of time on which they rest. The paper concludes with a brief consideration of the problem of granularity-a problem of considerable significance in temporal reasoning, which has yet to be satisfactorily treated in a temporal logic.

Journal of Symbolic Computation, 1996

Chronolog(MC) is an extension of logic programming based on a linear-time temporal logic with multiple granularity of time calledTLC. A Chronolog(MC) program consists of a clock definition, a clock assignment and a program body. Each predicate symbol appearing in the program body is associated with a local clock through the clock definition and assignment. This paper investigates the logical basis of the language, presents a clocked temporal resolution where time-matching is essential, and in particular proposes three algorithms for time-matching. The paper also discusses the declarative semantics of Chronolog(MC) programs in terms of clocked temporal Herbrand models. It is shown that Chronolog(MC) programs also satisfy the minimum model semantics. The language can be used to model a wide range of simulation systems and other relevant tasks where the notion of dynamic change is central.

Proceedings Ninth International Symposium on Temporal Representation and Reasoning

Representing and reasoning with both temporal constraints between classes of events (e.g., between the types of actions needed to achieve a goal) and temporal constraints between instances of events (e.g., between the specific actions being executed) is a ubiquitous task in many areas of computer science, such as planning, workflow, guidelines and protocol management. The temporal constraints between the classes of events must be inherited by the instances, and the consistency of both types of constraints must be checked. In this paper, we propose a general-purpose domain-independent knowledge server dealing with these issues. In particular, we propose a formalism to represent temporal constraints, we show two algorithms to deal with inheritance and to perform temporal consistency checking, and we study the properties of the algorithms.

Data & Knowledge Engineering, 2003

Real-Time Systems, 1992

A substantially large class of programs operate in distributed and real-time environments, and an integral part of their correctness specification requires the expression of time-critical properties that relate the occurrence of events of the system. We focus on the formal specification and reasoning about the correctness of such programs. We propose a system of temporal logic, RTCI'L (Real-Time Computation Tree Logic), that allows the melding of qualitative temporal assertions together with real-time constraints to permit specification and reasoning at the twin levels of abstraction: qualitative and quantitative. We argue that many practically useful correctness properties of temporal systems, which need to express timing as an essential part of their functionality requirements, can be expressed in RTCTL. We develop a model-checking algorithm for RTCTL whose complexity is linear in the size of the RTCTL specification formula and in the size of the structure. We also present an essentially optimal, exponential time tableau-based decision procedure for the satisfiability of RTCTL formulae. Finally, we consider several variants and extensions of RTCTL for real-time reasoning.

Cognitive science, 1982

Much previous work in artificial intelligence has neglected representing time in all its complexity. In particular, it has neglected continuous change and the indeterminacy of the future. To rectify this, I have developed a first-order temporal logic, in which it is possible to name and prove things about facts, events, plans, and world histories. In particular, the logic provides analyses of causality, continuous change in quantities, the persistence of facts (the frame problem), and the relationship between tasks and actions. It may be possible to implement a temporal-inference machine based on this logic, which keeps track of several "maps" of a time line, one per possible history.

2006 IEEE International Conference on Information Reuse & Integration, 2006

Modelling, reasoning about and integrating knowledge based on multiple time granularities in knowledge-based systems is important, especially when talking about events that take place in the real world. Formal approaches based on temporal logics have been successfully applied in many application domains of knowledge-based systems where the notion of dynamic change (that is, evolution of a system through time) is central. This paper presents a methodology based on temporal logic to deal with knowledge based on multiple time granularities in knowledge-based systems. The methodology includes an approach to the representation of timing systems, a method used for representing facts and rules in a knowledge-based system that involve multiple time granularities, and several deductive reasoning techniques.

2013

This dissertation describes research into new methods for automated temporal reasoning. For this purpose, several frameworks are available in literature. Chapter 1 presents a concise literature survey that provides a new overview of their interrelation. In the remainder of the dissertation, the focus is on quantitative frameworks, i.e. temporal constraint networks. Specifically, it is aimed at the subclass of Simple Temporal Networks (STNs) with the goal of assembling an algorithmic toolkit for dealing with the full set of temporal constraint networks. Temporal constraint networks find application in such diverse areas as space exploration, operation of Mars rovers, medical informatics, factory scheduling, and coordination of disaster relief efforts. Chapter 2 describes properties of the STN, both known and previously unknown, and investigates the question: "What is the Simple Temporal Problem (STP)?" Although the STP is the subject matter of many publications, a formal de...