On the Semantics of Scenario-Based Specification Based on Timed Computational Tree Logic (original) (raw)

Timed behavior trees and their application to verifying real-time systems

… Conference, 2007. ASWEC …, 2007

Behavior Trees (BTs) are a graphical notation used for formalising functional requirements and have been successfully applied to several case studies. However, the notation currently does not support the concept of time and consequently its application is limited to non-real-time systems.

Temporal logics for real-time system specification

ACM Computing Surveys, 2000

The specification of reactive and real-time systems must be supported by formal, mathematically-founded methods in order to be satisfactory and reliable. Temporal logics have been used to this end for several years. Temporal logics allow the specification of system behavior in terms of logical formulas, including temporal constraints, events, and the relationships between the two. In the last ten years, temporal logics have reached a high degree of expressiveness. Most of the temporal logics proposed in the last few years can be used for specifying reactive systems, although not all are suitable for specifying real-time systems. In this paper we present a series of criteria for assessing the capabilities of temporal logics for the specification, validation, and verification of real-time systems. Among the criteria are the logic's expressiveness, the logic's order, presence of a metric for time, the type of temporal operators, the fundamental time entity, and the structure of time. We examine a selection of temporal logics proposed in the literature. To make the comparison clearer, a set of typical specifications is identified and used with most of the temporal logics considered, thus presenting the reader with a number of real examples.

Scenario-based verification of real-time systems using Uppaal

Formal Methods in System Design, 2010

This article proposes two approaches to tool-supported automatic verification of dense real-time systems against scenario-based requirements, where a system is modeled as a network of timed automata (TAs) or as a set of driving live sequence charts (LSCs), and a requirement is specified as a separate monitored LSC chart.

Comments on temporal logics for real-time system specification

ACM Computing Surveys, 2009

The article "Temporal Logics for Real-Time System Specification" surveys some of the relevant literature dealing with the use of temporal logics for the specification of real-time systems. Unfortunately, [3] introduces some imprecisions that might create some confusion in the reader. While a certain degree of informality is certainly useful when addressing a broad audience, imprecisions can negatively impact the legibility of the exposition. We clarify some of the remarks of [3] on a few topics, in an effort to contribute to the usefulness of the survey for the reader.

Temporal logic for scenario-based specifications

2005

We provide semantics for the powerful scenario-based language of live sequence charts (LSCs). We show how the semantics of live sequence charts can be captured using temporal logic. This is done by studying various subsets of the LSC language and providing an explicit translation into temporal logic. We show how a kernel subset of the LSC language (which omits variables, for example) can be embedded within the temporal logic CTL*. For this kernel subset the embedding is a strict inclusion.

Expressing and organizing real-time specification patterns via temporal logics

Journal of Systems and Software, 2009

Formal specification models provide support for the formal verification and validation of the system behaviour. This advantage is typically paid in terms of effort and time spent in learning and using formal methods and tools. The introduction and usage of patterns have a double impact. They stand for examples on how to cover classical problems with formal methods in many different notations, so that the user can shorten the time to understand if a formal method can be used to meet his purpose and how it can be used. Furthermore, they are used for shortening the specification time, by reusing and composing different patterns to cover the specification, thus producing more understandable specifications which refer to commonly known patterns. For these reasons, both interests in and usage of patterns are growing and a higher number of proposals for patterns and pattern classification/organisation has appeared in literature. This paper reports a review of the state of the art for real-time specification patterns, so as to organise them in a unified way, while providing some new patterns which complete the unified model. The proposed organization is based on some relationships among patterns as demonstrated in the paper. During the presentation the patterns have been formalised in TILCO-X, whereas in appendix a list of patterns with formalizations in several different logics such as TILCO, LTL, CTL, GIL, QRE, MTL, TCTL, RTGIL, is provided disguised as links to the locations where such formalizations can be recovered and/or are directly reported, if found not accessible in literature; this allows the reader to have a detailed view of all the classified patterns, including the ones already added. Furthermore, an example has been proposed to highlight the usefulness of the new identified patterns completing the unified model.

A constraint-based approach for specification and verification of real-time systems

1997

We develop a general constraint logic programming (CLP) based framework for specification and verification of real-time systems. Our framework is based on the notion of timed automata that have traditionally been used for specihing real-time systems. In our framework, a user models the ordering of real-time events as the grammar of a language accepted by a timed automata, the real-time constraints on these events are then captured as denotations of the grammar productions specijied by the usel: The grammar can be speciJied as a Definite Clause Grammar (DCG), while the denotations can be speccped in constraint logic. The resulting specijication can hence be regarded as a constraint logic program (CLP), and is executable. Many interesting properties of the real-time system can be verc3ed by posing appropriate queries to this CLP program. A major advantage of our approach is that it is constructive in nature, i.e., it can be used for computing the conditions under which a property will holdfor a given real-time system. Our framework also suggests new types of formalisms that we call Constraint Automata and Timed Push-down Automata.

Embedding time granularity in a logical specification language for synchronous real-time systems

Science of Computer Programming, 1993

Embedding time granularity in a logical specification language for synchronous real-time systems, Science of Computer Programming 20 (1993) 141-171. Formal methods have proved to be highly beneficial in the requirements specification phase of software production and are particularly valuable in the development of real-time applications (the most critical software systems). Unfortunately, most common specification languages are inadequate for real-time applications because they lack a quantitative representation of time. In this paper, we define a logical language to specify the temporal constraints of the wide-ranging class of real-time systems whose components have dynamic behaviours regulated by very different time constants. We motivate the need for allowing the consistent treatment of different time scales in formal specifications of these systems with the purpose of enhancing the naturalness and practical usability of the notation. The logical specification language is based on a revised version of the specification language TRIO. We first present the features of the basic logical language; then, we semantically and axiomatically define its granularity extension in a topological logic framework. Finally, we show some examples of its application.

Communicating TILCO: a model for real-time system specification

Formal techniques for the specification of real-time systems must be capable of describing a set of relationships expressing the temporal constraints among events and actions: properties of invariance, precedence, periodicity, liveness and safety conditions, etc. This paper describes CTILCO, an extension of TILCO (Temporal Interval Logic with Compositional Operators). CTILCO introduces the Communication among components specified in TILCO and allows the adoption of decomposition/composition mechanisms. TILCO has been expressly designed for the specification of realtime systems. CTILCO is based on time intervals and can concisely express temporal constraints with time bounds, such as those needed to specify real-time systems. It can be used to verify the completeness and consistency of specifications, as well as to validate system behavior against its requirements and general properties. CTILCO has been formalized by using the theorem prover Isabelle/HOL. CTILCO specifications satisfying certain properties are executable. CTILCO is defined in terms of theorems and allows the system specification and the formal proof of properties including composition/decomposition with communications. An example of system specification and validation has been also included.

Specifying Real-Time Requirements for SDL Specifications — A Temporal Logic-Based Approach

Protocol Specification, Testing and Verification XV, 1996

The expressiveness of many state-transition based formal description techniques, e.g. the ITU-TS standardised Specification and Description Language (SDL), does not capture hard real-time requirements. In telecommunications systems engineering, hard real-time requirements, however, are an important class of properties. They occur in the description of progress properties in telecommunications protocols as well as in the specification of real-time related of Quality of Service (QoS) requirements. We suggest integrating functional system properties, given as SDL specifications, with real-time requirements expressed in terms of real-time temporal logic formulas. We call the resulting specifications 'complementary specifications'. First, we show the inexpressiveness of SDL with respect to hard real-time requirements. Next, we define a common model theoretic foundation which allows SDL specifications to be used jointly with temporal logic specifications. Then we give examples of commonly used real-time related QoS requirements, namely delay bound, delay jitter, and isochronicity. We also discuss the specification of various QoS mechanisms, like QoS negotiation, QoS monitoring and jitter compensation. Finally, we point at related formal verification problems.