Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2):189-- 215, April 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....These techniques are all forms of combinatorial optimization. Details of these algorithms are omitted here for brevity. A team of scientists at the University of Pennsylvania developed ACSR and GCSR. These specification languages were created so that systems could be analyzed using VERSA [4] before prototypes were made. VERSA can identify if a specific scheduling algorithm will work for a system, but can not answer the more general schedulability question of does any feasible schedule exist. 3.2 Relation to Previous Research There are similarities between the scheduling problem ....

D. Clarke, I. Lee, and H.-L. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer Software Engineering, 3(2), 1995.

....specified by ACSR VP is schedulable. In this section we introduce schedulability analysis of real time systems based on equivalence check between ACSR VP processes. To facilitate the analysis of ACSR specification we have used the Verification, Execution, and Rewriting System for ACSR (VERSA)[5, 6]. VERSA is an interactive toolkit that includes features for algebraic analysis, equivalence checking, state space analysis and interactive execution of ACSR process expressions. The correctness of the realtime system presented in this paper has been verified with the assistance of the VERSA ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....space explosion problem and hence their associated verification problem has high time space complexity if decidable at all. Many Operational Formal methods and techniques were adapted to tackle difficulties that arise on physical design modeling. Process algebraic approaches are the most numerous [39, 30, 66, 17] but there are also Petri Net [37] and automata [35] based approaches. Another way to classify these tools is through their ability to model the preemption of operations. Support of Preemption Modeling. These tools are able to model the effect of sharing the processor on execution time of ....

....account the Share of resources where contention for resources is arbitrated according to fix and static priorities. 130 Shared Processors Modeling. Processors are resources. Actions that compete for them are arbitrated according a fixed priority scheme. Verification Technique. There is a tool [30] supporting the process algebraic view that provides bisimulation algorithms to compare designs against specifications. Reachability analysis tools are also provided. Queries. Queries can be solved if they are rephrased as a reachability problem. Complexity. As all state exploration based ....

D. Clarke, I. Lee and H.-L. Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer Software Engineering, 3 (2), 1995.

....for CTSM using this example. x1: x1 1, y1: 0 tr1: x1 0 y1 =4, e x2 , l0 l1 l2 tr2: x2 0, f (x2) tr4: y2 =6, h tr3: x1 3, g (x2) l3 Figure 4.2: A Simple CTSM Proposal Draft 32 4. 1 Equivalence Relations Bisimulation equivalence plays an important role in the verification of systems [23, 7]. In many algebraic approaches, the specification Spec of system behaviors is specified as a simple process and the implementation Imp of the system behaviors is specified as a more complex process. The correctness of Imp is captured by bisimulation between Imp and Spec; that is, they describe the ....

Duncan Clarke, Insup Lee, and Hong liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Technical Report MS-CIS-93-77, Dept. of CIS, Univ. of Pennsylvania, Sept 1993. 89 Proposal Draft 90

....the data space. At the same time, we will optimize our implementation with efficient data structures and garbage collection to give better results. We also plan to develop graphical interface for TREAT. The work is part of our research in developing effective tools based on state space exploration [6]. 1 The experiment has been performed on a SparcStation with 64MB of primary memory and 64MB of swap memory ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....transition systems. Furthermore, ACSR strong equivalence, which is a congruence relation with respect to all ACSR operators, allows modular specification and verification within the ACSR formalism. Recently, ACSR has been implemented in VERSA (Verification, Execution, and Rewrite System for ACSR) CLX95] a toolkit which includes a text based user interface, a rewrite system based on ACSR algebraic laws, an equivalence checker, and a simulator for interactive process execution. Figure 1.1: GCSR Top down Specification and Analysis Environment A problem with the ACSR formalism is that a process ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995. 73 Graphical Specification and Refinement of Real-Time Systems 74

....the University of Pennsylvania to build a framework for the development of real time systems. The CSR paradigm offers process algebraic formalisms, Algebra of Communicating Shared Resources (ACSR) LBGG94] and Graphical Communicating Shared Resources (GCSR) BALC95] along with the toolkit VERSA [CLX95] 93 VERSA supports syntactic manipulation, simulation, and analysis of ACSR specifications. Integrating two tools VERSA and TREAT will provide the effective analysis of ACSR and GCSR. TREAT generates compact and efficient state space that can be fed back into VERSA for process algebraic ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....integrate the data space minimization algorithm and the reachability graph construction algorithm presented in this paper. At the same time, we will optimize our implementation to give better results. The work is part of our research in developing effective tools based on state space exploration [4]. We are also currently investigating other properties such as time bounds between events that can be checked directly from the reachability graph generated by our algorithm. ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....have an edge between them. This limitation is natural since in a Modechart specification, timing constraints can be expressed between two sequential modes with a transition. The work described in this paper is part of our research in developing effective tools based on state space exploration [5]. So far, we have developed Communicating Timed State Machines (CTSM) as a formalism that can be used to design and implement analysis algorithms based on state space exploration. CTSM is a state machine including one to many communication, message passing, data variables, and real time. We have ....

Duncan Clarke, Insup Lee, and Hong liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Technical Report MS-CIS-93-77, Dept. of CIS, Univ. of Pennsylvania, Sept 1993.

....the data space minimization algorithm and the reachability graph construction algorithm presented in this paper. At the 25 same time, we will optimize our implementation to give better results. The work is part of our research in developing effective tools based on state space exploration [4]. We are also currently investigating other properties such as time bounds between events that can be checked directly from the reachability graph generated by our algorithm. ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....unit. ACSR extends CCSR with the notion of instantaneous events and synchronization, and includes a set of laws complete for finite state processes [Br emond Gr egoire et al. 1997] To promote the use of ACSR in the specification and analysis of real time systems, we have implemented a tool VERSA [Clarke et al. 1995]. PARAGON is a toolset that extends the capability of VERSA by a providing graphical user , 3 interface, graphical specification language and visual simulation. The paper is organized as follows. Section 2 presents the paradigm of Communicating Shared Resources, which forms the basis for ....

....menu allow the user to perform refinement of GCSR specifications. Details of GCSR refinement are given in [Ben Abdallah 1996] and are beyond the scope of this presentation. PARAGON uses XVERSA [D.Clarke et al. 1996] as the back end analysis tool. XVERSA, which is an X windows interface to VERSA [Clarke et al. 1995], has been designed for analysis of ACSR specifications. GCSR specifications are exported into XVERSA by translating them into ACSR. Analysis functionality added by XVERSA is illustrated in Figure 4. State space exploration routines allow users to perform reachability analysis and deadlock ....

Clarke, D., I. Lee, and H.-L. Xie (1995), "VERSA: A Tool for the Specification and Analysis of ResourceBound Real-Time Systems," Journal of Computer and Software Engineering 3 , 2.

....with the expressiveness of GCSR and ACSR, as well as in our evaluation of the benefits of integrating the resource requirements with the functional and temporal requirements. We used PARAGON to model and analyze several case studies, e.g. the production cell [23, 1] scheduling problems [3, 6], avionic applications [4, 2] and various versions of the railroad crossing system benchmark [14, 1, 21] In this paper, we illustrate the GCSR language and analysis techniques applied to parts of the production cell case study. This example represents a realistic, industrial real time ....

D. Clarke, I. Lee, and H.L. Xie. VERSA: A Tool for the Specification and Analysis of ResourceBound Real-Time Systems. Journal of Computer and Software Engineering, 3(2):185--215, April 1995.

....in plain English the problem that will serve as running example in the following sections. Section 4 presents specification of the problem using GCSR, the formal graphical notation used by the PARAGON front end. Section 5 discusses verification of the railroad crossing example using XVERSA [CLX95], the back end verification package of the PARAGON toolset. Section 6 illustrates potential pitfalls in the design and their detection through verification. 2 Overview of the Toolset PARAGON toolset is a CASE system for visual specification and verification of distributed real time systems. It ....

....package of the PARAGON toolset. Section 6 illustrates potential pitfalls in the design and their detection through verification. 2 Overview of the Toolset PARAGON toolset is a CASE system for visual specification and verification of distributed real time systems. It augments the VERSA system [CLX95], developed by the Real Time Group at the University of Pennsylvania, with a graphical editor for GCSR language. Figure 1 shows the overall structure of the PARAGON system. Term Rewriting State Space Exploration Equivalence Testing Interactive Execution Text Based Interface VERSA X Windows ....

D. Clarke, I. Lee, and H.-L. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....together with a cpu allocation. In addition, the development of the GCSR language is motivated by two other concerns: one is to support the modular, hierarchical, and thus, scalable specification of real time systems; the other is to benefit from the analysis techniques [3, 10] and toolset [4] developed for the Algebra of Communicating Shared Resources (ACSR) timed process algebra that is developed within the CSR paradigm. Statecharts and Modechart support modularity through their notions of state and mode, respectively; they, however, lack a notion of scopes for variables since they ....

....[1] the second way of defining the semantics of GCSR allows a designer to interchangeably use the graphical and textual notations, for example, to specify the high level view of a system graphically and fill the details of components textually. In addition, since we already have developed VERSA [4], a toolset for the specification, syntactic manipulation, execution, and equivalence checking of ACSR specifications, we can use VERSA to analyze GCSR specifications by an automated translation from GCSR to ACSR. We have extended VERSA with a graphical user interface that allows the drawing, ....

[Article contains additional citation context not shown here]

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....Introduction PARAGON toolset is a CASE system for visual specification and verification of distributed realtime systems. Specification is based upon process algebras ACSR (Algebra of Communicating Shared Resources) 6] and its graphical counterpart GCSR [3] The toolset augments the VERSA system [5, 4], developed by the Real Time Group at the University of Pennsylvania, with a graphical editor and simulator for GCSR language. Figure 1.1 shows the overall structure of the PARAGON system. The user s view of the tool is provided by the GCSR and XVERSA user interfaces. XVERSA interface provides a ....

.... 00000 00000 00000 00000 00000 11111 11111 11111 11111 11111 00000 00000 00000 00000 11111 11111 11111 11111 00000 00000 00000 00000 00000 11111 11111 11111 11111 11111 000000 000000 000000 000000 000000 111111 111111 111111 111111 111111 Cycle[0] a[1] 1) a[2] 1) a[3] 1) a[4] 1) a[5] ,1) a[0] 1) b) Figure 2.8: The use of conditional edges. usual logical connectives. Figure 2.8 (a) gives an example of a parameterized specification using conditional edges. Figure 2.8 (b) presents an equivalent specification without parameterization. Currently, conditional edges are not ....

D. Clarke, I. Lee, and H.-L. Xie. VERSA: A tool for the specification and analysis of resourcebound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....This is done using the notion of ACSR priority which allows the specification of scheduling among several possible alternatives. Third, ACSR has a proof technique that can be used to verify properties of instruction specifications written in ACSR. There also is an available tool, called VERSA [2], which allows the programmer to interactively execute, analyze, and rewrite ACSR specifications. Our formal processor specification based on ACSR is useful in several areas. For instance, the specification provides an assembly programmer precise meaning of instructions with respect to timing ....

....process. A ToyP program is translated to an indexed set of ACSR processes. We obtain the timing properties of the original ToyP program by simplifying the corresponding ACSR processes using ACSR laws. We are currently experimenting with ToyP instruction specifications using ACSR tool kit, VERSA [2]. We also have modeled various floating point instructions and out of order instruction sequence execution. We are currently investigating more complex superscalar architecture such as caches and pipelines. We also are working on the formal specifications of various branch instructions, ....

D. Clarke, I. Lee, and H. Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Technical Report MS-CIS-9377, Dept. of CIS, Univ. of Pennsylvania, Sept 1993.

....to prove equivalence between algebraic expressions, combined with some mapping proofs. Development of mechanical proof methods for for process algebras is still preliminary. To evaluate the effectiveness of these reasoning techniques, prototype tools have been developed, such as those in [6, 5]. Althoughthe approach proposed in this paper is similar to reachability analysis of timed petri nets, e.g. 30, 35, 29, 26] there are several major differences. The various Petri net approaches all have mechanical proof techniques but lack a specification language, so do not provide the ....

D. Clarke, I. Lee, and H. Xie. Versa: A tool for the specification and analysis of resource-bound real-time systems. Technical Report MS-CIS-93-77, University of Pennsylvania, Department of Computer and Information Science, September 1993.

....operators make it possible to construct and analyze a specification in a modular and hierarchical fashion. This is essential for a large scale system which, in practice, is specified and analyzed incrementally in terms of its components. We have implemented a toolkit based on ACSR, called VERSA [Cla95], which has three major functions: rewriting, equivalence testing, and interactive execution. The rewrite system facilitates the rewriting of ACSR processes according to ACSR laws that preserve prioritized strong equivalence. At the direction of the user, the rewrite system applies predefined ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: a tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), 1995.

....priorities. Similar to other process algebras, ACSR has well defined semantics, the notion of equivalence based on bisimulation and a sound and complete set of laws. ACSR has a proof technique that can be used to verify properties of specifications written in ACSR. It also has a tool, called VERSA [2], that allows the programmer to interactively execute, analyze, and rewrite ACSR specifications. It, however, lacks a graphical interface. In this paper, we give a clear, consistent and precise semantics of Modechart using ACSR. This makes it possible to combine the advantages of a graphical ....

Duncan Clarke, Insup Lee, and Hong liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Technical Report MS-CIS-93-77, Dept. of CIS, Univ. of Pennsylvania, Sept 1993.

....non trivial systems without computer aided tools. As a step toward providing an integrated set of tools for specification, analysis, testing and code generation based on formal methods, we have developed tools for specification and analysis of real time systems based on ACSR with discrete time [19]. We are currently augmenting the tool set with a graphical specification language which has precise correspondence with ACSR [10] We plan to build a tool based on the dense time ACSR theory presented in this paper after we extend ACSR to support hybrid systems. Equivalence between ACSR processes ....

D. Clarke, I. Lee, and H.L. Xie. VERSA: A Tool for the Specification and Analysis of ResourceBound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....detailed design specification graphically. If two specifications are equivalent under a congruence relation, we can replace one for the other inside a larger system. This in turn makes modular specification and verification possible within the GCSR formalism. Since we already have developed VERSA [3], a toolkit for the specification, syntactic manipulation, execution, and analysis of ACSR specifications, GCSR specifications can also be analyzed using VERSA by translating GCSR to ACSR. The remainder of the paper is organized as follows. Section 2 presents the GCSR computation model and syntax. ....

D. Clarke, I. Lee, and H. L. Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....take exactly one time unit. ACSR extends CCSR with the notion of instantaneous events and synchronization, and includes a set of laws complete for finite state processes [11] To promote the use of ACSR in the specification and analysis of real time systems, we have implemented a tool called VERSA [13]. PARAGON is a toolset that extends the capability of VERSA by providing graphical user interface, graphical specification language and simulation, as well as modifying it to handle larger specifications. The paper is organized as follows. Section 2 presents the paradigm of Communicating Shared ....

....a textual specification may be preferable, both in terms of readability and the time it takes to construct the specification. Moreover, different users may have different personal preferences. PARAGON uses XVERSA [20] as the back end analysis tool. XVERSA, which is an X windows interface to VERSA [13], has been designed for analysis of ACSR specifications. GCSR specifications are exported into XVERSA by translating them into ACSR. Analysis functionality added by XVERSA is illustrated in Figure 13. State space exploration routines allow users to perform reachability analysis and deadlock ....

D. Clarke, I. Lee, and H.-L. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....termination. Second, we are investigating how to do model checking using a minimal state space generated by our algorithm for properties written in trace logic used with the producer consumer example. Third, we are implementing the minimization algorithm as part of the tool kit called VERSA [3]. This would allow us to experimentally evaluate its effectiveness. Fourth, we are developing minimization techniques based on notions of equivalence other than bisimulation. Fifth, we have extended communicating state machines with time and probability and is currently investigating how to ....

Duncan Clarke, Insup Lee, and Hong liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Technical Report MS-CIS-93-77, Dept. of CIS, Univ. of Pennsylvania, Sept 1993.

....relations make it possible to compare specifications (e.g. requirements and design) and to replace one specification for another inside a larger system. This in turn makes modular specification and verification possible within the ACSR formalism. Recently, ACSR has been implemented in VERSA [2], a toolkit for the specification, syntactic manipulation, execution, and analysis of ACSR specifications. Similar to most other formal specification languages, however, ACSR is based on a textual notation that often produces cumbersome, difficult to understand specifications. In an effort to make ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....( Corresponds to bar over events in traditional process algebra notation, as in e. ffl Optionally suffixed by a comma separated list of integer indices enclosed in square brackets ( and ] ffl The keywords tau and t represent the distinguished event label . ffl Examples in Out tau e[1,1] 3.3 Resource Name Constants ffl Identifiers. ffl Optionally suffixed by a comma separated list of integer indices enclosed in square brackets ( and ] ffl Examples cpu Printer cell[34] 3.4 Process Constants ffl NIL is the only process constant. ffl Deadlocked process; performs no ....

....union of two or more sets containing elements of the same base type. ffl Example Union[ r,Set[s[i] i,1,5] Intersection: Intersect[ ffl Usage Intersect[es1, esn] Forms the intersection of two or more sets containing elements of the same base type. ffl Example Intersect[ r[1],r[2] r[3] r[2] s] Complement: Complement[ ffl Usage Complement[es1,es2] Forms the complement of set es1 with respect to universe es2. The elements of es1 and es2 must be of the same base type. ffl Example Complement[ r[3] Set[r[i] i,1,5] 5.9 Prefix ( process) Event Prefix: ....

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....specifications that are hard to understand even in the case of simple examples. In addition, the development of GCSR addressed two concerns: support the modular, hierarchical, and thus scalable, specification of real time systems; and benefit from the analysis techniques [6] 7] and tool set [8] developed for ACSR. Scalability is an essential feature in any specification language (and in particular graphical languages) for large scale applications. GCSR supports scalability through its well defined notions of modularity and hierarchy. In GCSR, the visibility scope of communication ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....a graphical representation of timing constraints; 2) deriving time efficient test suites from those timing constraints; and (3) applying tests to ACSR process models and reporting the results. These tools are an extension of the Verification, Execution and Rewrite System for ACSR (VERSA)[4]. VERSA is a tool for creating ACSR process models and analyzing them using traditional process algebraic methods including state space exploration. The remainder of this paper is organized as follows. Section 2 presents the formalisms that we use: a graphical specification language for ....

....the last output was a falling bus voltage. The sender s constraint graph describes the following constraints on behavior: ffl From the subgraph labeled wh t: LeadingBitError 0 0 UP[1] to WH T DOWN[1] to wh T UP[2] to WH T DOWN[2] 2Q T,2Q T) DOWN[3] 0 Restart[1] to WH T UP[4] DOWN[4] to wh T UP[3] 2Q T,2Q T) UP[1] 0 0 0 DOWN[1] 0 0 0 WH T wh T e Start: e [0,infty) 0,infty) wh t InBit0[1] InBit1[1] InBit0[2] InBit1[2] Empty[1] InBit0[3] InBit1[3] Empty[2] Graph: Philips Audio Control Protocol Sender 0 Restart[2] 4Q T,4Q T) 2Q T,2Q T) 2Q T,2Q T) ....

[Article contains additional citation context not shown here]

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....a graphical representation of timing constraints; 2) deriving time efficient test suites from those timing constraints; and (3) applying tests to ACSR process models and reporting the results. These tools are an extension of the Verification, Execution and Rewrite System for ACSR (VERSA)[CLX95]. VERSA is a tool for creating ACSR process models and analyzing them using traditional process algebraic methods including state space exploration. The remainder of this paper is organized as follows. Section 2 presents our graphical specification formalism for describing real time constraints. ....

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....process models and reporting the results. These tools are an extension of the Verification, Ex Timing Requirements Test Generation Test Execution Test Results ACSR Implementation Test Suite Optimization Test Suite Figure 1: Structure of Testing Method ecution and Rewrite System for ACSR (VERSA) [4]. VERSA is a tool for creating ACSR process models and analyzing them using traditional process algebraic methods including state space exploration. The remainder of this paper is organized as follows. Section 2 presents the formalisms that we use: a graphical specification language for describing ....

.... wh T e Start: e [0,infty) 0,infty) wh t InBit0[1] InBit1[1] InBit0[2] InBit1[2] Empty[1] InBit0[3] InBit1[3] Empty[2] Graph: Philips Audio Control Protocol Sender 0 Restart[2] 4Q T,4Q T) 2Q T,2Q T) 2Q T,2Q T) 4Q T,4Q T) 2Q T,2Q T) DOWN[2] 2Q T,2Q T) UP[2] UP[3] 2Q T,2Q T) DOWN[4] to WH T to wh T UP[4] 0 UP[1] DOWN[1] to wh T to WH T to WH T Figure 7: Constraint Graph Specification for Sender tester process. The state space of the tester process applied to the receiver process will be constructed and searched for states that can execute success and ....

[Article contains additional citation context not shown here]

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....a graphical representation of timing constraints; 2) deriving time efficient test suites from those timing constraints; and (3) applying tests to ACSR process models and reporting the results. These tools are an extension of the Verification, Execution and Rewrite System for ACSR (VERSA)[CLX95]. VERSA is a tool for creating ACSR process models and analyzing them using traditional process algebraic methods including state space exploration. The remainder of this paper is organized as follows. Section 2 presents our graphical specification formalism for describing real time constraints. ....

....has been drawn and saved to a file, a custom filter program is run to verify the syntax of the graph. Since tests are modeled by ACSR processes, we have implemented our test derivation and application techniques by modifying the existing process editing and analysis tool for ACSR, known as VERSA[CLX95]. VERSA is an interactive system for creating real time system models using ACSR. Its features include syntax checking, an algebraic rewriting system, state space construction and analysis, and interactive execution of process expressions. Enhancements to the VERSA system include (1) the ....

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....Execution, and Rewrite System for ACSR (VERSA) is an integrated set of tools for developing system models using ACSR. We present here an overview of the features that are pertinent to the development of the ATM switching system example. For a more complete presentation of VERSA s capabilities see [7]. VERSA is an interactive system with a text based interface. Description and analysis of system models in ACSR is facilitated by the following features and capabilities: ffl Compilation. Finite state ACSR agent expressions can be translated into their underlying LTS representation. Translation ....

D. Clarke, I. Lee, and H. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....ACSR has language level support for specifying synchronization, resource requirements and static priority mechanisms of real time systems. Moreover, a toolkit based on ACSR has been developed and it has been successfully applied to specification and analysis of a number of well known examples [LCX95, CLX95]. However, ACSR is not adequate to serve as the basis for a general framework for schedulability analysis, since it has no notion of dynamic priorities and does not support value passing communication. To address priority driven scheduling problems better we have created an extended version of ....

....some authors. In this section, we describe the validation and schedulability analysis of real time systems based on checking the equivalence of ACSR VP processes. To facilitate the analysis of ACSR specifications we have created the Verification, Execution, and Rewrite System for ACSR (VERSA) [CLX95]. VERSA is an interactive toolkit that includes features for algebraic analysis, equivalence checking, state space analysis and interactive execution of ACSR process expressions. To apply VERSA to the schedulability analysis of ACSR VP processes we manually translate value passing processes into ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

....is a formalism that has language level support for specifying synchronization, resource contention, static priority mechanisms of real time systems. We have also developed a toolkit based on ACSR, which has been successfully applied to specification and analysis of a number of well known examples [17, 4]. In this paper, we extend ACSR, called ACSR VP (ACSR Value Passing) with value passing communication and dynamic priorities, and illustrate how to use it to specify and analyze priority driven real time systems. ACSR VP can model, in a modular fashion, a wide range of real time systems ....

....(x max) chan; 1) x : V(x) x max) V(max) Figure 3: Priority Inheritance in ACSR VP (i = 1; Delta Delta Delta ; n) In this section, we describe the schedulability analysis of real time systems based on the equivalence checking of ACSR VP processes. 5. 1 Equivalence Relations VERSA [17, 4] is a tool that assists in the algebraic analysis of real time specifications written in ACSR. With the translation of ACSR VP to ACSR, VERSA can also be used to analyze ACSR VP. An important technique that VERSA supports is the equivalence checking of ACSR processes. In ACSR, if a design ....

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer and Software Engineering, 3(2), April 1995.

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Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2):189-- 215, April 1995.

No context found.

Duncan Clarke, Insup Lee, and Hong-Liang Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2):189-- 215, April 1995.

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D. Clarke, I. Lee, and H.-L. Xie. VERSA: A tool for the specification and analysis of resource-bound real-time systems. Journal of Computer and Software Engineering, 3(2), April 1995.

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Clarke D., Lee I., Xie H. "VERSA: A tool for the Specification and Analysis of Resource-Bound Real-Time Systems" From internet. 184

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D. Clarke, I. Lee, H.L. Xie. VERSA: A Tool for the Specification and Analysis of Resource-Bound Real-Time Systems. Journal of Computer Software Engineering, 3 (2), 1995.

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