R. Reiter. Formalizing database evolution in the situation calculus. In Proc. of the Int. Conf. on FGCS, 1992.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....resources more adequately than sets and, moreover, it is more e#cient to compute with multisets instead of sets. In [13] it was also shown that the equational logic approach can handle database transaction and objects in much the same way as database transactions and objects are handled in [26] and [1] respectively. As an example consider the class hierarchy depicted in Figure 1 and suppose that an action move(O, L 1 , L 2 ) has been defined for the class object which moves an object O from location L 1 to location L 2 . The conditions and e#ects of this action are L 1 ) and L ....

....(3) 6) is inherited from the class object . However, 7) is defined for the class f object and, thus, is more specific than (6) and should be preferred. 3 The approaches of [1] or [13] do not model the concept of overriding through specificity in class hierarchies. Neither does the approach of [26] allow to specify more specific transactions in deductive databases. In this paper we extend the equational logic approach of [16, 13] such that the most specific action description is preferred. Specificity and the use of multisets to represent situations are discussed more thoroughly in the ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. of the Int. Conf. on FGCS, 1992.

.... where the condition and effect of actions are multisets of facts [48, 22] In [23] it is also shown that the equational logic approach can handle database transactions as well as objects and methods in much the same way as database transactions as well as objects and methods are handled in [44] and [1] respectively. It has turned out that inheritance of methods comes for free in the approaches of [1] and [23] but that neither approach allows overriding of methods. As an example, consider a scenario with a top class of objects and its subclass of fragile objects along with a method drop ....

....are broken after they have been dropped. In an object oriented framework, this is typically modeled by defining a (refined) method drop for the subclass of fragile objects, which as it is more specific overrides the method drop inherited from the top class. Unfortunately, both approaches [44] as well as [1] do not provide a mechanism to suppress the application of the less specific method and, hence, nothing can be concluded about the state of the vase after being dropped. In this paper, we extend the equational logic programming approach of [28, 23] such that the concept of ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing database evolution in the situation calculus. In Proceedings of the International Conference on Fifth Generation Computer Systems, 1992.

....logic viz. by using equational logic without loosing expressive power. In [7] it is also shown that the equational logic approach can handle database transaction as well as objects and methods in much the same way as database transactions as well as objects and methods are handled in [12] and [1] respectively. It has turned out that the inheritance of methods comes for free in the approaches of [1] and [7] but that neither approach allows overriding of methods. As an example, consider a scenario with a top class of objects, its subclass of fragile objects, and a method drop . ....

R. Reiter. Formalizing database evolution in the situation calculus. In Proceedings of the International Conference on Fifth Generation Computer Systems, 1992.

....insertion into EMP or an update to EMP, the new SAL is checked, and if it exceeds 100,000, then the JobTitle of this employee is added to HPaid, assuming that it was not there already. This is straightforward to model using the language that we have described already. Indeed, following Reiter [32], each database relation is modeled as a fluent. For simplicity, we eliminate fields in the relations that are not relevant for the example and assume that the language is conveniently extended with subsorts of the sort D . We use the fluent emp that takes an employee number, a job title, a ....

REITER, R. Formalizing database evolution in the situation calculus. In Proceedings of the InternationalConference on Fifth Generation Computer Systems (June 1992), pp. 600--609.

....when complete information on the initial situation is available. In particular the information on the initial situation can be seen as a relational database and action as specified by the preconditions and successor state axioms can be seen as operations that change the state the the database [11, 10, 6]. In this paper we show how to exploit such a correspondence to build a system for reasoning about actions based on standard relational database technology [8, 4] In particular, by exploiting a relational DBMS, the system is able to perform in very large action theories both Projection, i.e. ....

R. Reiter, `Formalizing database evolution in the situation calculus', in Proceedeings of the International Conference on Fifth Genearation Computer Systems, pp. 600--609, (1992).

....procedure for integrity checking of database updates. The question whether such an unfolding procedure is of practical use for general problem solving in temporal domains is not dealt with in Dung s paper. 7 Discussion In [12] a First Order Logic solution to the frame problem was proposed. [30] uses the same type of theory to formalise database evolution. This type of theory is a form of situation calculus which shows a strong similarity with the completion of a program D. Result=2 is replaced by do=2. Instead of using the meta predicate Holds=2, 30] adds one additional argument to ....

....to the frame problem was proposed. 30] uses the same type of theory to formalise database evolution. This type of theory is a form of situation calculus which shows a strong similarity with the completion of a program D. Result=2 is replaced by do=2. Instead of using the meta predicate Holds=2, [30] adds one additional argument to each fluent predicate; i.e. an atom Holds(p(x) t) is contracted to the atom p(x; t) As a consequence the law of inertia has to be stated for each fluent. An example taken from [30] is given below: 8St; C; A; S : P oss(A; S) enrolled(St; C; do(A; S) A = ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing Database Evolution in the Situation Calculus. In Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....of database updating, we spend more attention to the issue of temporal reasoning itself, for example by analysing the relationship between backward persistence and forward persistence axioms in our approach and in [13] and below by showing how A could be extended for indeterminate actions. [20] formalises database evolution using situation calculus theories in First Order Logic. The completion of a program D shows a strong relationship with these theories. 20] replaces Result=2 by do=2. Instead of using the meta predicate Holds=2, each fluent predicate is added one additional argument; ....

....forward persistence axioms in our approach and in [13] and below by showing how A could be extended for indeterminate actions. 20] formalises database evolution using situation calculus theories in First Order Logic. The completion of a program D shows a strong relationship with these theories. [20] replaces Result=2 by do=2. Instead of using the meta predicate Holds=2, each fluent predicate is added one additional argument; i.e. an atom Holds(P (x) t) is contracted to the atom P (x; t) As a consequence the law of inertia has to be stated for each fluent. 20] investigates the ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing Database Evolution in the Situation Calculus. In Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....knowledge base implies that fact should have been true in the knowledge base prior to the current update request. This kind of reasoning can be achieved only when both the history of events occurring in the real world as well as a history of the database updates are both recorded in the database [Rei92, Sri88]. Recording such histories enables one to reason about the two notions of time, namely valid time and transaction time, that are required in advanced knowledge base applications [Sri93] ffl The second interpretation is plausible when the user is aware of the fact that the knowledge base is ....

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. Int. Conf. on Fifth Generation Computer Systems (FGCS-92), 1992.

....formalisms and to make this diversity manageable. This of course could only happen if such a framework is based on clear mathematical grounds and helps to facilitate mathematical analysis and comparison of different methods of representation. There are several recent publications, including [Rei91, Rei92, San92, GL92] which attempt the development of such a framework. The attempts differ in scope and methods but share a large number of basic assumptions. Our work is based on the approach originated in [GL92] That paper introduces a highlevel action description language A, gives its semantics based on the ....

R. Reiter. Formalizing database evolution in the situation calculus. In ICOT, editor, Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....of fluents that holds an instance of the time is the state of the world at that instance. Actions are the cause of situation transitions: a result function is used to map (state, situation) pairs to the new situation resulting from the execution of that action in that situation. Reiter [REI, 91] REI, 93] and [REI, 93a] has desribed how one may represent databases and their update transactions within the situation calculus. The basic idea consists in realizing that a database evolve in time, so that updatable relations should have an explicity state argument representing the current database ....

....holds an instance of the time is the state of the world at that instance. Actions are the cause of situation transitions: a result function is used to map (state, situation) pairs to the new situation resulting from the execution of that action in that situation. Reiter [REI, 91] REI, 93] and [REI, 93a] has desribed how one may represent databases and their update transactions within the situation calculus. The basic idea consists in realizing that a database evolve in time, so that updatable relations should have an explicity state argument representing the current database state. This ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing database evolution in the situation calculus. In Proceedings of the Fifth Generation Computer Systems, pages 600-609, Tokyo, Japan, (1992).

....insertion into EMP or an update to EMP, the new SAL is checked, and if it exceeds 100,000, then the JobTitle of this employee is added to HPaid, assuming that it was not there already. This is straightforward to model using the language that we have described already. Indeed, following Reiter [34], each database relation is modeled as a fluent. For simplicity, we eliminate fields in the relations that are not relevant for the example and assume that the language is conveniently extended with subsorts of the sort D 12 . We use the fluent emp that takes an employee number, a job title, a ....

REITER, R. Formalizing database evolution in the situation calculus. In Proceedings of the InternationalConference on Fifth Generation Computer Systems (June 1992), pp. 600--609.

.... us that the gas has been turned off before striking the match succeeded: Gamma j= hturn on gas; while :match lit do (press push) ignite f lame spot i( heating operative ) h(any Gamma ; any Gamma ) turn off gasi ) Inferences as the one above are answers to historical queries [26, 25] i.e. queries of the form: if from the initial state described by S we execute the complex action ff getting OE, then does this implies that before the termination of ff, a given formula OE 0 is true in some state, or that a given action a has been executed These questions can be answered by ....

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. Int. Conf. on Fifth Generation Computer Systems, pages 600--609, 1992.

....of construction, we could use parallel and prioritized circumscription [9] in connection to these new objects in order to obtain the new specification. 6. The problem of data type specification, and many other specification problems in computer science, e.g. database transaction specifications [15], procedure specifications [8, 2] etc. have explicit and sometimes more hidden commonsense aspects. As in everyday life, we find in computer science many instances of commonsense reasoning [14] In this regard, it is not surprising that John McCarthy s circumscription, originally developed for ....

Reiter, R. "Formalizing Database Evolution in the Situation Calculus". Proceedings of the Fifth Generation Computer Systems, Tokyo, June 92. To appear.

....formalisms and to make this diversity manageable. This of course could only happen if such a framework is based on clear mathematical grounds and helps to facilitate mathematical analysis and comparison of different methods of representation. There are several recent publications, including [Rei91, Rei92, San94, GL92] which attempt the development of such a framework. The attempts differ in scope and methods but share a large number of basic assumptions. Our work is based on the approach originated in [GL92] That paper introduces a high level action description language A, gives its semantics based on the ....

R. Reiter. Formalizing database evolution in the situation calculus. In ICOT, editor, Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....resources more adequately than sets and, moreover, it is more efficient to compute with multisets instead of sets. In [13] it was also shown that the equational logic approach can handle database transaction and objects in much the same way as database transactions and objects are handled in [26] and [1] respectively. As an example consider the class hierarchy depicted in Figure 1 and suppose that an action move(O; L 1 ; L 2 ) has been defined for the class object which moves an object O from location L 1 to location L 2 . The conditions and effects of this action are fjon(O; L 1 )jg ....

....(3) 6) is inherited from the class object . However, 7) is defined for the class f object and, thus, is more specific than (6) and should be preferred. 3 The approaches of [1] or [13] do not model the concept of overriding through specificity in class hierarchies. Neither does the approach of [26] allow to specify more specific transactions in deductive databases. In this paper we extend the equational logic approach of [16, 13] such that the most specific action description is preferred. Specificity and the use of multisets to represent situations are discussed more thoroughly in the ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. of the Int. Conf. on FGCS, 1992.

....Pinto, Pablo Saez 1 , Deepak Kapur and Mahadevan Subramaniam 2 Abstract. Automated support for proving integrity constraints (ICs) on deductive database update specifications is developed using an induction theorem prover, Rewrite Rule Laboratory (RRL) 6] The approach proposed by Reiter [9, 11, 10] for solving the frame problem for such applications in a language of the situation calculus is used as a basic framework. Integrity constraints are propositions that are expected to be true in every accessible state of a database, and they should be provable from the specification of the ....

.... axioms take the form poss(a; s) oe f(do(a; s) j OE f (a; s) f(s) OE Gamma f (a; s) Thus, a fluent f holds after performing a possible action a if it held before the action was performed and the action did not falsify f ( OE Gamma f ) or the fluent was made true by a (OE f ) [10, 11, 12]. There will be one such axiom per fluent predicate. For instance, for classified we have: poss(a; s) oe classified(isbn; id; do(a; s) j (a = classifyBook(isbn; id) classified(isbn; id; s) a 6= deleteBook(id) Integrity Constraints: Aside from the specifications given above, in general a ....

R. Reiter. Formalizing Database Evolution in the Situation Calculus. In Proceedings of the Fifth Generation Computer Systems, Tokyo, Japan, June 1992.

....de l Evolutif dans une Base de Connaissances. 1 Introduction The concern in this paper is to formalize update under transition constraints in an incomplete information setting. A wide variety of proposals for formalizing database (knowledge base) update semantics exists (e.g. 9] 11] 15] 4] [12] [13] In this paper we investigate a substantially different proposal exploiting some features of linear logic [7] Our aim is to provide a mechanism to perform updates such that if we start with a consistent database then the result of an update is a new database which is always consistent . ....

R. Reiter, 1992. Formalizing Database Evolution in the Situation Calculus, in Proceedings of FGCS `92.

.... changes to a circuit design may be forbidden if the new design violates certain conditions (e:g : limits on cost, size, or power consumption) It is worth noting that post conditions can be awkward, if not impossible to express in other formalism of action, such as the situation calculus [42, 55]. Example 2.5 (Post Conditions) If the atom happy is a query (i :e: has no side effects) then the expression ins:won Omega happy denotes an update followed by a test. Intuitively, it means, insert won into the database, and then check that happy is true. In other words, the database state ....

R. Reiter. Formalizing database evolution in the situation calculus. In Conf. on Fifth Generation Computer Systems, 1992.

....complete transformation of the temporal reasoning language A (which allows to represent uncertainty on the initial state) to OLP FOL. In comparison, the transformation from A to ELP proposed in [11] is not sound in general and not complete. In ongoing work, we mapped Reiter s situation calculus [28] to OLP FOL (under a stronger semantics than the one used in this paper) despite the fact that this theory contains a second order induction axiom. In another experiment, a terminological language was mapped to OLP FOL. An interesting issue which falls outside the scope of this paper is the ....

R. Reiter. Formalizing Database Evolution in the Situation Calculus. In Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....2.3 Situation Calculus The situation calculus is a methodology for specifying the effects of elementary actions in first order classical logic. It was introduced by McCarthy [McC63] and then further developed by McCarthy and Hayes [MH69] Recently, it has received renewed development by Reiter [Rei92a,Rei92b,Rei91] Unlike the approaches discussed so far, the emphasis in the situation calculus is on specifying elementary actions, not on combining them into complex procedures. As such, the situation calculus does not have a repertoire of built in actions, such as assert and retract in Prolog, ....

R. Reiter. Formalizing database evolution in the situation calculus. In Conference on Fifth Generation Computer Systems, 1992.

.... changes to a circuit design may be forbidden if the new design violates certain conditions (e:g : limits on cost, size, or power consumption) It is worth noting that post conditions can be awkward, if not impossible to express in other formalism of action, such as the situation calculus [12, 15]. Example 2.5 (Post Conditions) If the atom b is a query (i :e: has no side effects) then the expression ins:c Omega b denotes an update followed by a test. Intuitively, it means, insert c into the database, and then check that b is true. In other words, the database state is first ....

R. Reiter. Formalizing database evolution in the situation calculus. In Conf. on Fifth Generation Computer Systems, 1992.

....procedure for integrity checking of database updates. The question whether such an unfolding procedure is of practical use for general problem solving in temporal domains is not dealt with in Dung s paper. 7 Discussion In [12] a First Order Logic solution to the frame problem was proposed. [29] uses the same type of theory to formalise database evolution. This type of theory is a form of situation calculus which shows a strong similarity with the completion of a program D. Result=2 is replaced by do=2. Instead of using the meta predicate Holds=2, 29] adds one additional argument to ....

....to the frame problem was proposed. 29] uses the same type of theory to formalise database evolution. This type of theory is a form of situation calculus which shows a strong similarity with the completion of a program D. Result=2 is replaced by do=2. Instead of using the meta predicate Holds=2, [29] adds one additional argument to each fluent predicate; i.e. an atom Holds(p(x) t) is contracted to the atom p(x; t) As a consequence the law of inertia has to be stated for each fluent. An example taken from [29] is given below: 8St; C; A;S : P oss(A; S) enrolled(St; C; do(A; S) A = ....

[Article contains additional citation context not shown here]

R. Reiter. Formalizing Database Evolution in the Situation Calculus. In Proc. of the International Conference on Fifth Generation Computer Systems, pages 600--609, 1992.

....transaction logs and historical queries, the complexity of query evaluation, actualized transactions, logic programming approaches to updates, database views and state constraints. This paper consolidates and expands on a variety of results, some of which have been described elsewhere (Reiter [46, 45, 44]) Address correspondence to Department of Computer Science University of Toronto Toronto, Canada M5S 1A4 email: reiter ai.toronto.edu THE JOURNAL OF LOGIC PROGRAMMING c fl Elsevier Science Inc. 1994 655 Avenue of the Americas, New York, NY 10010 0743 1066 94 7.00 1. INTRODUCTION Our ....

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. Fifth Generation Computer Systems, pages 600--609, Tokyo, June 1 - 5, 1992.

.... questions for planning would be something like: If this plan is executed, would such and such ever be true during the plan execution (Will block A ever be on block B during the execution of this plan ) Within the framework of this paper, it is possible to develop a theory of such queries (Reiter [13]) Acknowledgements Many of my colleagues provided important conceptual and technical advice. My thanks to Leo Bertossi, Alex Borgida, Craig Boutilier, Charles Elkan, Michael Gelfond, Gosta Grahne, Russ Greiner, Joe Halpern, Hector Levesque, Vladimir Lifschitz, Fangzhen Lin, Wiktor Marek, John ....

R. Reiter. Formalizing database evolution in the situation calculus. In Proc. Fifth Generation Computer Systems, pages 600--609, Tokyo, June 1 - 5, 1992.

....and (5) as a consequence, we obtained that Reiter s solution is correct and complete for a broad class of problems. 7 Future Work There are still several issues that need to be addressed. We have only considered Reiter s original solution, not its extension to some kinds of ramifications [7] In [15, 10], Reiter formalizes the evolution of a database according to his solution to the frame problem [14] In [1] this formalization was positively assessed with Sandewall s methodology. In that paper, there was a restriction to ground databases, i.e. without null values. It seems interesting to ....

Reiter, R.: Formalizing database evolution in the situation calculus. Fifth Generation Computer Systems, Tokyo, Japan (1992)

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