Temporal Logic Programming Research Articles

Axiomatic semantics of projection temporal logic programs

In this paper, we investigate the axiomatic semantics of the projection temporal logic programming language MSVL. To this end, we employ Propositional Projection Temporal Logic (PPTL) as an assertion language to specify the desired properties. We give a set of state axioms and state inference rules. In order to deduce a program over an interval, we also formalise a set of rules in terms of a Hoare logic-like triple. These rules enable us to deduce a program into its normal form and from the current state to the next one. They also enable us to verify properties over intervals. In this way, an axiom system for proving the correctness of MSVL programs is established. The axiom system is proved to be sound and relatively complete with respect to an operational model of MSVL, and give an example showing how the axiom system works. Finally, we employ a recently developed prototype verifier based on PVS as an example of semi-automatic verification using MSVL.

Declarative specification and verification of service choreographiess

Service-oriented computing, an emerging paradigm for architecting and implementing business collaborations within and across organizational boundaries, is currently of interest to both software vendors and scientists. While the technologies for implementing and interconnecting basic services are reaching a good level of maturity, modeling service interaction from a global viewpoint, that is, representing service choreographies, is still an open challenge. The main problem is that, although declarativeness has been identified as a key feature, several proposed approaches specify choreographies by focusing on procedural aspects, leading to over-constrained and over-specified models. To overcome these limits, we propose to adopt DecSerFlow, a truly declarative language, to model choreographies. Thanks to its declarative nature, DecSerFlow semantics can be given in terms of logic-based languages. In particular, we present how DecSerFlow can be mapped onto Linear Temporal Logic and onto Abductive Logic Programming . We show how the mappings onto both formalisms can be concretely exploited to address the enactment of DecSerFlow models, to enrich its expressiveness and to perform a variety of different verification tasks. We illustrate the advantages of using a declarative language in conjunction with logic-based semantics by applying our approach to a running example.

Operational semantics of Framed Tempura

This paper investigates the operational semantics of temporal logic programs. To this end, a temporal logic programming language called Framed Tempura is employed. The evaluation rules for both the arithmetic and boolean expressions are defined. The semantic equivalence rules for the reduction of a program within a state is formalized. Furthermore, the transition rules within a state and transition rules over an interval between configurations are also specified. Moreover, some examples are given to illustrate how these rules work. Thus, the executable behavior of framed programs can be captured in an operational way. In addition, the consistency between the operational semantics and the minimal model semantics based on model theory is proved in detail.

Framed temporal logic programming

A Projection Temporal Logic is discussed and some of its laws are given. After that, an executable temporal logic programming language, called Framed Tempura, is formalized. A minimal model-based approach for framing in temporal logic programming is presented. Since framing destroys monotonicity, canonical models–used to define the semantics of non-framed programs–are no longer appropriate. To deal with this, a minimal model theory is developed, using which the temporal semantics of framed programs is captured. The existence of a minimal model for a given framed program is demonstrated. A synchronous communication mechanism for concurrent programs is provided by means of the framing technique and minimal model semantics.

Temporal Contextual Logic Programming

The importance of temporal representation and reasoning is well known not only in the database community but also in the artificial intelligence one. Contextual Logic Programming [António Porto and Luís Monteiro. Contextual logic programming. In Giorgio Levi and Maurizio Martelli, editors, Proceedings 6th Intl. Conference on Logic Programming, Lisbon, Portugal, 19–23 June 1989, pages 284–299. The MIT Press, Cambridge, MA, 1989] (CxLP) is a simple and powerful language that extends logic programming with mechanisms for modularity. Recent work not only presented a revised specification of CxLP together with a new implementation for it but also explained how this language could be seen as a shift into the Object-Oriented Programming paradigm [Salvador Abreu and Daniel Diaz. Objective: In minimum context. In Catuscia Palamidessi, editor, ICLP, volume 2916 of Lecture Notes in Computer Science, pages 128–147. Springer, 2003]. In this paper we propose a temporal extension of such language called Temporal Contextual Logic Programming. Such extension follows a reified approach to the temporal qualification, that besides the acknowledge increased expressiveness of reification allows us to capture the notion of time of the context. Together with the syntax of this language we also present its operational semantics and an application to the management of workflows.

Temporal phylogenetic networks and logic programming

The concept of a temporal phylogenetic network is a mathematical model of evolution of a family of natural languages. It takes into account the fact that languages can trade their characteristics with each other when linguistic communities are in contact, and also that a contact is only possible when the languages are spoken at the same time. We show how computational methods of answer set programming and constraint logic programming can be used to generate plausible conjectures about contacts between prehistoric linguistic communities, and illustrate our approach by applying it to the evolutionary history of Indo-European languages.

Erratum to A framed temporal logic programming language

Erratum to A framed temporal logic programming language

A framed temporal logic programming language

We discuss the projection temporal logic (PTL), based on a primitive projection operator, prj. A framing technique is also presented, using which a synchronization operator, await, is defined within the underlying logic. A framed temporal logic programming language (FTLL) is presented. To illustrate how to use both the language and framing technique, some examples are given.

A PROOF PROCEDURE FOR TEMPORAL LOGIC PROGRAMMING

In this paper, we propose a new resolution proof procedure for the branching-time logic programming language Cactus. The particular strength of the new proof procedure, called CSLD-resolution, is that it can handle, in a more general way, open-ended queries, i.e. goal clauses that include atoms which do not refer to specific moments in time, without the need of enumerating all their canonical instances. We also prove soundness, completeness and independence of the computation rule for CSLD-resolution. The new proof procedure overcomes the limitations of a family of proof procedures for temporal logic programming languages, which were based on the notions of canonical program and goal clauses. Moreover, it applies directly to Chronolog programs and it can be easily extended to apply to multi-dimensional logic programs as well as to Chronolog(MC) programs.

PITL2MONA: Implementing a Decision Procedure for Propositional Interval Temporal Logic

Interval Temporal Logic (ITL) is a finite-time linear temporal logic with applications in hardware verification, temporal logic programming and specification of multimedia documents. Due to the logic's non-elementary complexity, efficient ITL-based verification tools have been difficult to develop, even for propositional subsets. MONA is an efficient implementation of an automata-based decision procedure for the logic WS1S. Despite the non-elementary complexity of WS1S, MONA has been successfully applied in problems such as hardware synthesis, protocol verification and theorem proving. Here we consider a rich propositional subset of ITL, PITL, whose expressive power is equivalent to that of WS1S, and in turn to that of regular languages. PITL not only includes operators such as chop (;), star (*) and projection (proj), but also past operators such as previous (-), chop in the past (˜) and since (S). We provide an interpretation of PITL formulas in WS1S, which led us to a direct translation from PITL formulas to MONA specifications. We present the tool PITL2MONA as an implementation of such translation. With PITL2MONA acting as a front-end, MONA is used as a decision procedure for PITL. To our knowledge, this is one of the few implementations of a decision procedure for PITL, the first one based on automata, and the only one which handles both projection and past operators. We have tested our implementation on a number of examples; we show in this paper the application of PITL and its MONA-based decision procedure in solutions to the dining-philosophers and a multimedia synchronisation problem, together with some experimental results on these and some other examples.

Temporal abstraction and inductive logic programming for arrhythmia recognition from electrocardiograms

This paper proposes a novel approach to cardiac arrhythmia recognition from electrocardiograms (ECGs). ECGs record the electrical activity of the heart and are used to diagnose many heart disorders. The numerical ECG is first temporally abstracted into series of time-stamped events. Temporal abstraction makes use of artificial neural networks to extract interesting waves and their features from the input signals. A temporal reasoner called a chronicle recogniser processes such series in order to discover temporal patterns called chronicles which can be related to cardiac arrhythmias. Generally, it is difficult to elicit an accurate set of chronicles from a doctor. Thus, we propose to learn automatically from symbolic ECG examples the chronicles discriminating the arrhythmias belonging to some specific subset. Since temporal relationships are of major importance, inductive logic programming (ILP) is the tool of choice as it enables first-order relational learning. The approach has been evaluated on real ECGs taken from the MIT-BIH database. The performance of the different modules as well as the efficiency of the whole system is presented. The results are rather good and demonstrate that integrating numerical techniques for low level perception and symbolic techniques for high level classification is very valuable.

Stratified negation in temporal logic programming and the cycle-sum test

We consider stratified negation in temporal logic programming. We demonstrate that the cycle-sum test (which was initially proposed for detecting deadlocks in the context of temporal functional programming) can also be used as a syntactic stratification test for temporal logic programming. Therefore, on the one hand we exhibit a class of temporal logic programs with negation which have a well-defined semantics, and on the other hand we provide further evidence that the cycle-sum test is a fundamental one in the area of temporal programming.

Temporal disjunctive logic programming

In this paper we introduce the logic programming languageDisjunctive Chronolog which combines the programming paradigms of temporal and disjunctive logic programming. Disjunctive Chronolog is capable of expressing dynamic behaviour as well as uncertainty, two notions that are very common in a variety of real systems. We present the minimal temporal model semantics and the fixpoint semantics for the new programming language and demonstrate their equivalence. We also show how proof procedures developed for disjunctive logic programs can be easily extended to apply to Disjunctive Chronolog programs.

Temporal representation and reasoning in artificial intelligence: Issues and approaches

Time is one of the most relevant topics in AI. It plays a major role in several areas, ranging from logical foundations to applications of knowledgedbased systems. In this paper, we survey a wide range of research in temporal representation and reasoning, without committing ourselves to the point of view of any specific application. The organization of the paper follows the commonly recognized division of the field in two main subfields: reasoning about actions and change, and reasoning about temporal constraints. We give an overview of the basic issues, approaches, and results in these two areas, and outline relevant recent developments. Furthermore, we briefly analyze the major emerging trends in temporal representation and reasoning as well as the relationships with other welldestablished areas, such as temporal databases and logic programming.

Branching-time logic programming: the language Cactus and its applications

Temporal programming languages provide a powerful means for the description and implementation of dynamic systems. However, most temporal languages are based on linear time, a fact that renders them unsuitable for certain types of applications (such as expressing properties of non-deterministic programs). In this paper we introduce the new temporal logic programming language Cactus, which is based on a branching notion of time. In Cactus, the truth value of a predicate depends on a hidden time parameter which varies over a tree-like structure. As a result, Cactus can be used to express in a natural way non-deterministic computations or generally algorithms that involve the manipulation of tree data structures. Moreover, Cactus appears to be appropriate as the target language for compilers or program transformers. Cactus programs can be executed using BSLD-resolution, a proof procedure based on the notion of canonical temporal atoms/clauses.

Modeling data-intensive reactive systems with relational transition systems

In this paper, the formalism of Relational Transition Systems (RTSes) is used to model data-intensive reactive systems, and four RTS models of reactive systems based on temporal logic programming, production systems, recurrence equations, and Petri nets are presented. The paper also describes different methods of comparison of the expressive powers of various RTSes in terms of the trajectories they can generate and carries out this comparison for the four RTS formalisms. It is shown that these formalisms have the same expressive power in the deterministic case. The paper also compares expressive powers of non-deterministic production systems and non-deterministic temporal logic programming systems. It is shown that, although the two formalisms are incomparable in the general case, their restricted versions are isomorphic to each other.

On the Expressiveness of Temporal Logic Programming

In this paper, we address expressiveness issues for temporal logic programming, and in particular for the language TEMPLOG. We focus on the temporal component of the expressiveness by considering the propositional fragment of the language, which we call PTEMPLOG. We prove that PTEMPLOG is able to express positive least-fixpoint temporal properties, which (up to a convention concerning atomic formulas) corresponds to finitely regular ω-languages. Finally, we consider the extension of PTEMPLOG With stratified negation and we show that it is able to express all ω-regular languages.

Temporal and modal logic programming

Temporal and modal logic programming

Extending Temporal Logic Programming with Choice Predicates Non-determinism

Extending Temporal Logic Programming with Choice Predicates Non-determinism

Temporal logic programming for assembly sequence planning

A temporal-constraint logic programming framework for the specification and automatic verification and synthesis of assembly sequences is developed. The implemented tool is based on the formulated and derived precedence properties for a general mechanical assembly. This tool, called the Mechanical Assembly Sequence Satisfiability Checker (MASS-C), supports the use of a subset of temporal logic for assembly constraint specification. MASS-C provides the logic programming framework by which the designer can be relieved of the tedium of finding the assembly sequences, and the assembly sequence planning process manifests itself in the implicit modelling of assembly sequences by acquiring and formulating the set of correct and complete assembly constraints as a logic program. MASS-C implements a class of temporal expressions as predicates for logic programming of assembly constraints. It provides facilities to either verify an assembly sequence or synthesise all assembly sequences that satisfy the specified constraints composed as a logic program. Two examples illustrate the use of MASS-C for such verification and synthesis.