Barringer, H., M. Fisher, D. Gabbay, and A. Hunter (1991). Meta-Reasoning in Executable Temporal Logic, in: J. Allen, R. Fikes, E. Sandewall, Proc. of the 2nd Int. Conf. on Principles of Knowledge Representation and Reasoning, KR'91.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....to allow modal and temporal connectives, that is based on a linear point structure of time. The linear point structure could lead us to the same problems as in the Grays s attempt. Another possibility could be the temporal logic with Since and Until and fixed point operators [Gabbay 89] Barringer et al. 91] However, as pointed by the authors the logic is based on the natural numbers as flow of time (linear structure) and is suitable for controlling process behaviour. Consequently, such logic is not suitable for our purposes as mentioned in section 1.3. The logic based on intervals proposed in ....

Howard Barringer, Michael Fisher, Dov Gabbay, and Anthony Hunter. Meta-reasoning in executable temporal logic. In Knowldege Representation, 1991.

....e ects are destroyed) and classical frame conditions for all literals. A detailed descritption of such encodings, and the induced plan search mechanisms, would override space limits and will be given elsewhere. The application of LTL to planning has been considered in other works. For example, [3] applies the executable temporal language METATEM [2] to planning and scheduling. F. Bacchus and F. Kabanza [1] use a version of temporal logic to specify temporally extended goals as sets of acceptable sequences of states, i.e. temporal models, and de ne correct plans as those whose execution ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In Proc. of the Second Int. Conf. on Principles of Knowledge Representation and Reasoning, 1991.

....system that may be open to the user. The naturalness of semantically based methods makes it possible to conceive mixed initiative planning systems, where proofs are expected to convey understandable information. The application of LTL to planning has been considered in other works. For example, [4] apply the executable temporal language METATEM [3] to planning and scheduling. F. Bacchus and F. Kabanza [2] use a version of temporal logic to specify temporally extended goals as sets of acceptable sequences of states, i.e. temporal models, and define correct plans as those whose execution ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In Proc. of the Second Int. Conf. on Principles of Knowledge Representation and Reasoning, 1991.

....For example, Stephan Biundo 1996; Koehler Treinen 1995) view planning as theorem proving in intervalbased temporal logics; Cimatti et al. 1997; Cimatti Roveri 1999) propose planning via model checking. Linear time temporal logic (LTL) has also been used (Bacchus Kabanza 1996a; 2000; Barringer et al. 1991), since it is based on a simple model of time and allows an easy and natural representation of a world that changes over time. In this work we propose the use LTL as a speci cation language for planning, keeping inside the planning as satis ability approach (Kautz Selman 1992) Di erently from ....

Barringer, H.; Fisher, M.; Gabbay, D.; and Hunter, A. 1991. Meta-reasoning in executable temporal logic. In Proc. of KR-91.

....(the model built so far) and, if it is true, the model is extended in order to make Future true. Although the main original motivation behind executable temporal logic is the specification and verification of reactive systems, their application to planning and scheduling has also been considered [2]. The view of a planning activity as model construction leads to a new logical approach to planning: a plan is a linear time temporal model of the set of formulae describing the domain constraints and goals. By contrast, the logical approach to planning is usually based on deduction, and plan ....

....planning are more easily exploitable, such as techniques for partial order, regression planning, least commitment, as well as control strategies to guide the search. In the planning perspective, the declarative past implies imperative future reading of formulae and their execution techniques in [2] correspond to a form of total order, forward chaining planning. In [4] a prefixed tableau calculus is proposed allowing the integration of the execution mechanism with new hooks and hints from classical planning systems research, in particular partial order and regression planning. In this work ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In Proc. of the Second Int. Conf. on Principles of Knowledge Representation and Reasoning, 1991.

....by checking the truth of P ast in the present history (the model built so far) and, if it is true, the model is extended in order to make Future true. In a planning setting, this reading of formulae and their execution techniques correspond to a form of total order, forward chaining planning [2]. We introduce a temporal language based on discrete, linear time, whose modal part is a sub language of propositional METATEM, and, similarly to [1] formulate an execution mechanism based upon model construction techniques related to analytic tableaux. We show that regression planning can be ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In Proc. of the Second Int. Conf. on Principles of Knowledge Representation and Reasoning, 1991.

....logic. In this section we introduce the temporal partial logic that we have defined to satisfy our requirements. Our approach is in line with what in [10] is called temporalising a given logic; in our case the given logic is partial logic. For more literature on temporal logic, for instance see [1], 2] 9] Definition 2.1 (Signature) A signature OE is an ordered sequence of (propositional) atom names. At(OE ) is the set of atoms based on OE, and Lit(OE ) is the set of literals based on OE. The formulae of the language will be the classical propositional formulae. Definition 2.2 ....

H. Barringer, M. Fisher, D. Gabbay, A. Hunter, Meta-Reasoning in Executable Temporal Logic, In: J. Allen, R. Fikes, E. Sandewall, Proc. of the 2nd Int. Conf. on Principles of Knowledge Representation and Reasoning, KR'91

....next meaning the next moment in time , until, etc. It has been applied in both, sequential and concurrent programs, for automatic verification but also for automatic synthesis. Temporal Logic has been proposed also as a programming language like the Tempura language [84] and the METATEM language [36, 13, 14]. This topic is not further analysed in this survey. For those interested I would recommend the section 1.3 in [38] as introductory text. Some relevant references are [68, 75, 45, 12, 37, 65] A final good quality of MTL I would remark is modularity. It can directly and neatly be combined with ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In Proc. KR'91, pages 40--49, 1991.

....at one level turns out to be a distributed system of modules when we look within it. Since we already know about implementing a module in MetateM here we just need to describe the arrangements for communication between modules. In CMP, we use broadcast message passing as outlined in [Fisher and Barringer, 1991]. Essentially this means that all announcements are potentially available for every module in the system to hear. But as usual, each module has an abstract interface specification indicating which predicates it listens to in its environment and which it may announce. Broadcast message passing ....

....repetition of messages. Of course, then the operational meaning of x reflects even less the semantics of yesterday. We will discuss this problem later when we will also note that the meta language facility described in the next subsection may also be of some help. 5. 5 Meta programming As shown in [Barringer et al. 1991] , there is much potential for meta language capabilities to be useful as part of a MetateM language. A meta language syntax allows formulas to be treated as objects for various purposes such as building interpreters and loop checking. A meta language operational sematics allows the program to ....

H Barringer, M Fisher, D Gabbay, and A Hunter. Meta-reasoning in executable temporal logic. In J Allen, R Filkes, and E Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning. Morgan Kaufmann, April 1991.

....do such [119, 120] Fisher discovered that Agent0 and PLACA used logic to define the mental states of agents but neither Agent0 nor PLACA truly executed the logic. Building off of his work with Wooldridge and his work with Barringer on programming in temporal logic and executing temporal logic [12, 13] and building off of Barringer s work on concurrent models using temporal logic [14] Fisher developed Concurrent MetateM [55, 53] This language has concurrently executing agents that communicate by broadcasting messages to the other agents in the system. Each agent is defined using temporal ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-reasoning in executable temporal logic. In R. Fikes and E. Sandewall, editors, Proceedings of Knowledge Representation and Reasoning (KR&R-91). Morgan Kaufmann Publishers: San Mateo, CA, April 1991.

....nothing about how to solve temporal conflicts on seasonal cycles. The same problems of reasoning about cyclic events were found when we tried to use other well known logics, such as Gabbay s temporal logic [Gabbay 87] the temporal logic with Since and Until and fixed point operators [Gabbay 89] Barringer et al. 91] Furthermore, these approaches have no commitment to both the durational aspects of temporal logic and with different levels of time granularity, but with the specification of possible states of the world in a single time scale. Another possibility would be Allen s system [Allen 84] Allen ....

Howard Barringer, Michael Fisher, Dov Gabbay, and Anthony Hunter. Meta-reasoning in executable temporal logic. In Knowldege Representation, 1991.

.... of the correctness of propositional METATEM, see [BFG 95] Applications Although much of the development of METATEM has been suspended in favour of Concurrent METATEM [Fis94] the language has applications in system modelling [FFO93] databases [FMO91] and meta level representation [BFGH91] 4.2 Temporal Resolution As we also consider the effect of the various restrictions on SNF has on Fisher s temporal resolution method [Fis91] here we briefly review this method. The clausal temporal resolution method consists of repeated applications of both step and temporal resolution ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), April 1991.

....representation of knowledge and the encoding of heuristics. In theory, METATEM also supports meta level reasoning. The logical basis of the framework includes the ability to name and manipulate formulae and rules and, thus, meta level capabilities are provided as basic mechanisms within METATEM [3]. Such mechanisms provide a wide range of flexibility in developing, reconfiguring and dynamically modifying the behaviour of systems. Meta level techniques also allow standard programming tools to be developed within a consistent logical framework. In METATEM family of logics, no explicit ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR'91), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

....concept of a reactive system is therefore at the very heart of METATEM. Although the original META TEM proposal did not address the issue of concurrency, the potential value of concurrently executing METATEM systems particularly for DAI applications was immediately recognised (Fisher and Barringer, 1991). Concurrent METATEM is a simple operational framework which allows societies of METATEM processes to communicate and cooperate. Note that although Concurrent METATEM may be regarded as a logic programming language, in that it has a well developed and motivated logical foundation) it is quite ....

.... (see also (Fisher, 1993) techniques for specifying and verifying Concurrent METATEM systems (see also (Fisher and Wooldridge, 1993) organisational structure in Concurrent METATEM; more) efficient algorithms for agent execution; meta level reasoning in METATEM and Concurrent METATEM (see also (Barringer et al. 1991)) a language for agent rules containing a belief component; and the development of a formal framework for the group structuring notion. 12 ....

Barringer, H., Fisher, M., Gabbay, D., and Hunter, A. (1991). Meta-Reasoning in Executable Temporal Logic. In Allen, J., Fikes, R., and Sandewall, E., editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts.

....it manipulates in order to decide what to do. Thus, to reason about the behaviour of Concurrent MetateM systems, we require some description of the formulae that each agent is manipulating at each moment in time. One way of doing this would be to use a first order temporal meta language (as in [4]) However, meta languages are notationally cumbersome, and can be confusing. What we propose instead is to use a multi modal language, which contain both temporal connectives and an indexed set of modal belief operators, one for each object. These belief operators will be used to describe the ....

.... system for Concurrent MetateM, since we made the assumption of synchronous action) However, it has the advantage of simplicity when compared to other methods for defining the semantics of the language (such as those based on dense temporal logic [13] or first order temporal meta languages [4]) More generally, logics similar to that developed herein can be used to reason about a wise class of DAI systems: those in which agents objects have a classic symbolic AI architecture. Such systems typically employ explicit symbolic representations, which are manipulated in order to plan and ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

....more advanced features of Concurrent METATEM. 5 Extensions of Concurrent METATEM Although the features we will describe in this section can be categorised as extra logical, the intention is that these extensions to the basic execution of temporal logic will be defined using meta level techniques [5], rather than system primitives. Note that several of these capabilities have yet to be implemented fully. 5.1 Dynamic interfaces The interface definition of an object defines the initial set of messages that are recognised by that object. However, the object may dynamically change the set of ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR'91), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

No context found.

H. Barringer, M. Fisher, D. Gabbay and A. Hunter. Meta-reasoning in executable temporal logic. In Principles of Knowledge Representation and Reasoning (KR'91), J. Allen, R. Fikes and E. Sandewall, pp. 40--49, Morgan Kaufmann, 1991.

.... then the algorithm is guaranteed to find a model of the specification [3] Using these properties we execute temporal logic specifications to generate a model [14] This has led to the approach of Executable Temporal Logics which have been implemented and applied in a variety of applications [4, 9, 22]. In the approach of executable temporal logics we view temporal logic specifications as programs. The model generated by executing the program is then the output from the program. Though we have not yet implemented the described inconsistency handling for the ViewPoints framework, some of the ....

H. Barringer, M. Fischer, D. Gabbay and A. Hunter (1991); "Meta-reasoning in Executable Temporal Logic"; Proceedings of 2nd International Conference on the Principles of Knowledge Representation and Reasoning, 40-49; Morgan Kaufmann.

....several messages. Complex varieties of message queue manipulation may be defined, depending on the properties of the Concurrent METATEM objects. Such an extension is being developed through the use of extended primitive predicates (an alternative approach is through the use of meta level features [4]) 3.2 Synchronisation Mechanisms There are two approaches to the synchronisation of asynchronously executing objects in Concurrent METATEM, outlined as follows. 1. An object asks for something, continues processing, but does something when the answer arrives. Thus, a request is made and ....

....message passing can be implemented on top of this. Such a mechanism can either be provided as part of the implementation of Concurrent METATEM, and made available through extra primitives, or can be provided by utilising meta level features within each Concurrent METATEM object (see [4] for an outline of these basic features) To provide point to point message passing using meta level features, every Concurrent METATEM object (that wishes to take part in such a scheme) must include a meta rule of the form send(me,X) X within its definition. Here me is the name of that ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts, April 1991.

....it manipulates in order to decide what to do. Thus, to reason about the behaviour of Concurrent METATEM systems, we require some description of the formulae that each agent is manipulating at each moment in time. One way of doing this would be to use a first order temporal meta language (as in [4]) However, meta languages are notationally cumbersome, and can be confusing. What we propose instead is to use a multi modal language, which contain both temporal connectives and an indexed set of modal belief operators, one for each object. These belief operators will be used to describe the ....

.... system for Concurrent METATEM, since we made the assumption of synchronous action) However, it has the advantage of simplicity when compared to other methods for defining the semantics of the language (such as those based on dense temporal logic [13] or first order temporal meta languages [4]) More generally, logics similar to that developed herein can be used to reason about a wise class of DAI systems: those in which agents objects have a classic symbolic AI architecture. Such systems typically employ explicit symbolic representations, which are manipulated in order to plan and ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

....for specifying and verifying Concurrent MetateM systems (see also [15] organisational structure in Concurrent MetateM; more) efficient algorithms 4 We comment on the use of mentalistic notions below. for object execution; meta level reasoning in MetateM and Concurrent MetateM (see also [4]) and a language for object rules containing a belief component. ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the International Conference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

.... of the language semantics (see also [12] techniques for specifying and verifying Concurrent METATEM systems (see also [15] organisational structure in Concurrent METATEM; more) efficient algorithms for object execution; meta level reasoning in METATEM and Concurrent METATEM (see also [4]) and a language for object rules containing a belief component. 4 We comment on the use of mentalistic notions below. ....

H. Barringer, M. Fisher, D. Gabbay, and A. Hunter. Meta-Reasoning in Executable Temporal Logic. In J. Allen, R. Fikes, and E. Sandewall, editors, Proceedings of the InternationalConference on Principles of Knowledge Representation and Reasoning (KR), Cambridge, Massachusetts, April 1991. Morgan Kaufmann.

No context found.

Barringer, H., M. Fisher, D. Gabbay, and A. Hunter (1991). Meta-Reasoning in Executable Temporal Logic, in: J. Allen, R. Fikes, E. Sandewall, Proc. of the 2nd Int. Conf. on Principles of Knowledge Representation and Reasoning, KR'91.

No context found.

Barringer, H., M. Fisher, D. Gabbay, and A. Hunter (1991). Meta-Reasoning in Executable Temporal Logic, in: J. Allen, R. Fikes, E. Sandewall, Proc. of the 2nd Int. Conf. on Principles of Knowledge Representation and Reasoning, KR'91.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC