Allen, Johannes, & Koomen (1983) Planning Using a Temporal World Model.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....complexity. Preprint submitted to Artificial Intelligence 1 Introduction The study of relation algebra originates in the nineteenth century and constitutes, along with Frege s quantifier logic, the foundation of modern logic [1,2] From the 1970s onwards, computer scientists working in planning [3,4] and temporal reasoning [5 11] rediscovered relation algebra. Later, scholars working in the field of Knowledge Representation, and specifically Spatial and Temporal Knowledge Representation, also used the formalism of relation algebra [10,12 18] For them, the principal method of reasoning ....

J. Allen, J. Koomen, Planning using a temporal world model, in: Proc. 8th International Joint Conference on Artificial Intelligence, Morgan Kaufmann, 1983, pp. 711--714.

....for the main results in x7, it is therefore situated near the end of the paper. The same is true for the final x11, in which the structure of the interval algebra over R is recalled. This paper continues a line of research inititated in [A81] A83] and pursued in [A84] AH85] AH87] AKa85] [AKo83], BL85] BL89] La87] LM87] LM88] LM88a] Li86] LB88] PA86] Schu86] Schu87] Schu88] Ts87] Ts87a] Val86] Val87] VK86] and [ZLS88] Some of the results in this paper were presented on April 5, 1989, to the Applied Mathematics Engineering Colloquium, Iowa State ....

....direct product of all possible interval algebras, i.e. the direct product of an indexed system of algebras containing (at least) one algebra from each isomorphism type of interval algebras. The relations listed above are studied in [vB83] and are used in some computer programs ( MB83] Si83] [AKo83]) x7. Consequences Theorem 14. i) Constraint satisfiability for C 2 [h1; 0i ; h1; 1i ; h0; 1i] is NP complete. The same is true for the symmetric subalgebra of C 2 [h1; 0i ; h1; 1i ; h0; 1i] ii) Constraint satisfiability for the the interval algebra over hR; i (or hQ; i) is NP complete. ....

James F. Allen and Johannes A. Koomen, Planning using a temporal world model, Proceedings of the Eighth International Joint Conference on Artificial Intelligence, Karlsruhe, W. Germany, August

....to define planning have been devoted to the forraM specification of planning programs [4] This is based on the widespread agreement that the data structures that these programs manipulate indeed represent plates. However, it is also widely understood that other data structures can represent plans [2]. Should we define again what planning is in these different representations Or should we try to give a representation independent definition that can be applied to several (and possibly all) representation frameworks Another aspect that is sometimes a source of confusion is the relationship ....

....been introduced in activity based planning frameworks [9] Instead, our discussion will focus on explicit representations of both state and input, given that in a dynamical system both input ad state have equal weight. We examine the modularity of an interval based STRIPS representation framework [2]. To conduct our anMysis, we consider a restricted BW domain with only two blocks, a and b, and a robot arm, arm; we concentrate on the representation of a simple plan to stak a on b. The relevant operators are given in Figure 3 (a) An operator specifies the facts that have to hold on the state ....

J.F Allen and J.A. Koomen. Planning using a temporal world model. In Proceedings of the 8th IJCAI, pages 741-747, William Kaufmann, 1983.

....thesis. His representation has further evolved as part of a larger effort to design a logic that captures propositions, events, actions, and plans that are qualified temporally. To the extent that this algebra of temporal relations is advocated for multiple tasks of reasoning and problem solving [6], we are justified in examining closely its properties. I view Allen s scheme as essentially answering the following question: Problem 1: How should one design a mechanism to infer new facts about the relationships between pairs of events, given ambiguous knowledge that holds between some of ....

J.F. Allen and J.A. Koomen. Planning Using a Temporal World Model. Proceedings of IJCAI-8, 1983, pp. 741-747.

....expressed within the causal link planner formalism. In order to do this, we use the temporal relations supported by usual conflict resolution, and precedence relation between instants. This allows us to post temporal constraints on plans without using usual methods of temporal planners like [Allen and Koomen, 1983] and [Ghallab and Laruelle, 1994] Keywords: Planning and Temporal reasoning. 1 Introduction When is concerned with a real life planning application, one has to face the following problems : actions take time, more than one action can occur at the same time, several actions can interact and ....

J.F. Allen & J.A. Koomen. "Planning using a Temporal World Model", In Proceedings of the Eight International Joint Conference on Artificial Intelligence, 1983, pp741-747.

....thesis. His representation has further evolved as part of a larger effort to design a logic that captures propositions, events, actions, and plans that are qualified temporally. To the extent that this algebra of temporal relations is advocated for multiple tasks of reasoning and problem solving [6], we are justified in examining closely its properties. I view Allen s scheme as essentially answering the following question: Problem 1: How should one design a mechanism to infer new facts about the relationships between pairs of events, given ambiguous knowledge that holds between some of ....

J.F. Allen and J.A. Koomen. Planning Using a Temporal World Model. Proceedings of IJCAI-8,198.3, pp. 741-747.

....developed in [CI88] than to ours. It handles point based predicates rather than interval predicates. Moreover, it is designed to handle relative timing information rather than quantitative timing information. In the artificial intelligence literature, there is a large body of work on intervals [All83, AK83, All84, AH85]. However, not much is proposed as usable methods for handling interval predicates with infinite extensions. Also, in most case only relative 21 timing information is considered. The work on interval temporal logics is limited to intractability and expressiveness results [HS86, Ven88] ....

J.F. Allen and J.F. Koomen. Planning using a temporal world model. In A. Bundy, editor, 8th IJCAI, pages 741--747, 1983.

....interesting taxonomies of actions (e.g. pushbutton actions, maintenance actions, etc. 1] They utilize the notion of trying to perform an action, as opposed to a simple execution of the action. Another interesting development is the study of planning algorithms within the interval temporal logic [6]. Unfortunately, this latter work seems to lack a careful analysis of soundness and completeness with respect to the underlying theory. It seems, however, that it would be very beneficial to study these issues in the realm of the situation calculus. 7.3 Calculus of Events. 7.3.1 A Critique. The ....

Allen, J. F., and Koomen, J. A. Planning using a temporal world model. In Proceedings of the Eighth International Joint Conference on Artificial Intelligence (IJCAI-83) (1983), pp. 741--747.

....diagnosis. Temporal reasoning has been considered in philosophy and logic since Thales and Zeno [19] however, it is only in the last two decades that temporal reasoning has been explicitly considered in artificial intelligence. McDermott and Allen, with their work in the early nineteen eighties [2 4,20], brought temporal reasoning into the AI mainstream. Other models for temporal reasoning include point algebras [32] semi intervals [10] temporal constraint networks [9] and weak representations of interval algebras [18] McDermott provides one of the earliest temporal representations [20] In ....

....one of the earliest temporal representations [20] In his approach, time is divided into a series of states with each state having an associated date, i.e. point in time. Facts are expressed as being true during particular states. Allen introduced interval temporal reasoning to the AI community [2, 4]. Allen s interval algebra is governed by 13 relations on the intervals. Each event has an associated interval, denoted [a, b] where a is the starting time point and b is the termination point. Temporal relationships between events are expressed as relations between their intervals. The relations ....

Allen, James F. and Johannes A. Koomen. "Planning Using a Temporal World Model." Proceedings of the Eight International Joint Conference on Artificial Intel ligence . 741--

....These systems will be introduced in section 2.2. More recent work on representations of time has concentrated on the interval rather than the point in time as the fundamental entity. This includes work by Allen and Koomen, who set out a view of planning using an interval based model of time [4]. Allen separately describes a system for maintaining consistency in the relationships between a set of intervals [5] This system is improved on in terms of both efficiency and consistency by Tsang [132] who refers time intervals to one another using a tree structure to get a 23 consistency ....

....DEVISER [133] operated in a spaceworld domain, and modelled operations as being extended over intervals in time, and possibly overlapping. Its representation of concurrent operations, however, did not allow the full range of possible relationships between intervals described by Allen and Koomen [4]. Wilkins SIPE [137] allowed for changes in the world other than those resulting directly from operations, although all operations were still done by a single agent. Whenever an operation is added to a plan in SIPE, a search is made of a list of domain rules to see if any of them are applicable ....

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J. F. Allen and J. Koomen. Planning using a temporal world model. In Proceedings of the 8th IJCAI, pages 741--747, 1983.

.... Unfortunately, the general planning problem is intractable [Cha87, Byl91] Several frameworks and methods have been proposed to address di#erent aspects of planning (see for instance [AHT90, HTD90, Wel99] We shall focus on the temporal planning paradigm, first adumbrated by Allen Koomen [AK83]. Unlike classical planning approaches, which take actions to be instantaneous, temporal planning regards actions as having duration. Durations are measured in terms of intervals. Here, we shall treat intervals in a metric context, and represent them in terms of their start and end points. This ....

....Durations are measured in terms of intervals. Here, we shall treat intervals in a metric context, and represent them in terms of their start and end points. This is the approach taken in parcPLAN [LR94, EKR96] which is a constraint based planning system with its origins in Allen Koomen [AK83]. 13 CHAPTER 1. INTRODUCTION 14 The parcPLAN system is, arguably, unique in that it integrates temporal and resource reasoning, thereby supporting the requirements of reasoning about action overlap. It also implements a constraint based strategy for introducing actions into a plan. Like other ....

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J. F. Allen and J. A. Koomen. Planning Using a Temporal World Model. In Proceedings of the Eighth International Joint Conference on Artificial Intelligence, IJCAI-83, pages 741--747, Karlsruhe, Germany, 1983.

....of partial satisfaction to de ne partial scenarios or optimal partial solutions. We propose two reasoning procedures for computing an optimal partial solution to a problem (or a complete solution if it exists) 1 Introduction Temporal reasoning is a vital task in many areas such as planning [2], scheduling [5] and natural language processing [6] Currently the main focus of research has been on how to represent temporal information and how to gain a complete solution from a problem. How the information is represented depends on the type of temporal reasoning that is needed. There are ....

J. Allen and J. Kooomen. Planning using a temporal world model. In Proceedings of the 8th International Joint Conference on Articial Intelligence (IJCAI), pages 741-747, Karlsruhe, W.Germany, 1983.

....system we are familiar with that would also solve those tasks is described in [8] It is 2 pm. The first task requires that the robot is in room 2 between 3 pm and 3.15 pm in order to do some unspecified actions. Reasoning about time intervals is feasible using interval logic. With TIME LOGIC [2] a planner based on interval logic exists. The planner considers temporal relations but not temporal quantities. It would not take great deal of effort to extend it with this feature. If it needs between 4 and 6 minutes to carry out the plan, it could begin moving the robot at 2.54 pm into room ....

J. F. Allen, J. A. Koomen. "Planning Using a Temporal World Model". Proceedings of the 8th International Joint Conference on Artificial Intelligence, pp 741-747, 1983.

....Perhaps the constraints describing the movement of the hand can be achieved directly. These ideas were expressed at AIPS 2000 by David Smith [10] expanded in [11] and Malik Ghallab, drawing on his experience with the IxTet system [8] 5] Similar ideas were expressed earlier by Allen and Koomen [1], and in considerable detail by Edward Tsang in his PhD thesis [12] Generative planning may not be so hopelessly too slow for control of real time systems as one might think. Quite a lot of planned actions happen over minutes or hours, not milliseconds. At ECP 99 [2] Nicola Muscettola, also ....

James Allen and J Koomen. Planning using a temporal world model. In IJCAI '83, pages 741-747, 1983.

....used to guide a planning search and reduce the potentially huge search space to a manageable size [18, 5, 13, 22] But the work on abstraction assumes that a plan is built without time constraints, so it is not applicable to problems that require incremental results. The work on temporal planning [1, 15, 17, 20] provides formalisms that represent the dynamic and continuous nature of a changing environment better than the discrete Strips style representation. But again these approaches fail to build plans in a useful way for time stressed situations. We have developed an approach to incremental planning ....

J. F. Allen and J. A. Koomen. Planning using a temporal world model. In Proceedings of IJCAI-83, pages 741--747. IJCAI, 1983.

....According to James Allen, an interval is an entity in its own right, not just a set of [cognitively untreatable] instants (Galton, 1995) Intervals may be given a more expressive reasoning power by defining interval to interval relations. Allen and Koomen defined thirteen irreducible relations in (Allen and Koomen, 1983), which include before, meets, overlaps, starts, and during. We make use of this notion later on in this paper. Consider the IG in Figure 1. Let an interval within an IG be defined by two vertices (i.e. lessons) By making use of Allen s Temporal Logic Relational Operators (Pelavin, 1986) the ....

Allen, J.F. and Koomen, J.A., (1983). Planning using a temporal world model. Proceedings of 8 th IJCAI, 41-747. 1983.

....merged with complex time models making it almost impossible to obtain complete algorithms showing an acceptable runtime behavior. 19 An early attempt of integrating time into a planning system is Allen s interval logic [All83, AKPT91] Experimental implementations using this formalism exist [AK83] but the algorithms remain incomplete, which can also be explained by the intractability results presented in [Hir95, NB95] A more recent attempt of dealing with resources and time in a planning system are the planners ZENO [PW94] and IxTeT [GL94, LG95] ZENO possesses a sound and complete ....

J. Allen and J. Koomen. Planning using a temporal world model. In Proceedings of the 8th International Joint Conference on Artificial Intelligence, pages 741--747, Karlsruhe, Germany, August 1983.

....sake of trying to be complete, a rule is specified in an unsound way leading to a synchronization choice that causes failure. We give an example of this in (Clement Durfee 1999b) where we also implement a hierarchical plan coordi 1 We will often abbreviate Allen s thirteen temporal relations (Allen 1983). Here, b is for the before relation. o is for overlaps. nation algorithm that uses summary information in the manner described above. Our evaluations show that coordinating at different levels of abstraction for different cost scenarios results in better performance. Thus, formalizing ....

....interaction of hierarchical plans. However, we also wanted the model to share important aspects of plans used by PRSs, HTNs, Allen s temporal plans, and many STRIPS style plan representations. As such, this theory of action tries to distill appropriate aspects of other theories, including (Allen Koomen 1983), Georgeff 1984) and (Fagin et al. 1995) CHiPs A concurrent hierarchical plan p is a tuple hpre, in, post, type, subplans, orderi. pre(p) in(p) and post(p) are sets of literals (v or :v for some propositional variable v) representing the preconditions, inconditions, and postconditions ....

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Allen, J. F., and Koomen, J. A. 1983. Planning using a temporal world model. In Proc. IJCAI, 741--747.

....choice that causes failure. We give an example of this in (Clement Durfee 1999b) where we also implement a hierarchical plan coordination algorithm that uses summary information in the manner described above. Our evaluations show 1 We will often abbreviate Allen s thirteen temporal relations (Allen 1983). Here, b is for the before relation. o is for overlaps. that coordinating at different levels of abstraction for different cost scenarios results in better performance. Thus, formalizing concurrent hierarchical plans, their execution, and the derivation of summary conditions is necessary to ....

....interaction of hierarchical plans. However, we also wanted the model to share important aspects of plans used by PRSs, HTNs, Allen s temporal plans, and many STRIPS style plan representations. As such, this theory of action tries to distill appropriate aspects of other theories, including (Allen Koomen 1983), Georgeff 1984) and (Fagin et al. 1995) CHiPs A concurrent hierarchical plan p is a tuple hpre, in, post, type, subplans, orderi. pre(p) in(p) and post(p) are sets of literals (v or :v for some propositional variable v) representing the preconditions, inconditions, and postconditions ....

[Article contains additional citation context not shown here]

Allen, J. F., and Koomen, J. A. 1983. Planning using a temporal world model. In Proc. IJCAI, 741--747.

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Allen, Johannes, & Koomen (1983) Planning Using a Temporal World Model.

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Allen J.F. and Koomen J.A., "Planning Using a Temporal World Model", In Proceedings of the 8 International Joint Conference on Artificial Intelligence, Karlsruhe, Germany, 1983, pp741-747.

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James F. Allen and Johannes A. Koomen, Planning using a temporal world model, Proceedings of the Eighth International Joint Conference on Arti cial Intelligence, Karlsruhe, W. Germany, August 1983.

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James F. Allen and Johannes A. Koonlen. Plan- ning using a temporal world model. ht /J- [Mye91] UAI'83, pages 741-747,. Kaxlsrulie, 1983.

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James Allen and Johannes Koomen. Planning using a temporal world model. In Eighth International Joint Conference on Artificial Intelligence, pages 741-747, 1983.

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Allen, J.F. & Koomen, J.A. (1983). Planning using a temporal world model. Proceedings of the 8 th IJCAI, 41-47.

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