Symbolic Model Checking Commitment Protocols Using Reduction

Commitment protocols have been widely used to capture flexible and rich interactions among agents in multi-agent systems. Although there are sev-eral approaches specifying commitment protocols, none of them synthesize for-mal specification and automatic verification of these protocols within the same framework. This paper presents a new approach to automatically verify the con-formance of commitment protocols having a social semantics with specifications at design time. The contributions of this paper are twofold: first, we present a new language to formally specify the commitment protocols, which is derived from a new logic extending íµí°íµí±‡ íµí°¿ * with modality of social commitments and actions on these commitments; and second, we develop a symbolic model checking algo-rithm for the proposed logic, which is used to express the protocol properties we aim to check such as safety and liveness. We also present experimental results of verifying the NetBill protocol as a motivating a...

Expert Systems with Applications, 2013

Although several approaches have been proposed to specify multi-agent commitmentbased protocols that capture flexible and rich interactions among autonomous and heterogeneous agents, very few of them synthesize their formal specification and automatic verification in an integrated framework. In this paper, we present a new logic-based language to specify commitment-based protocols, which is derived from ACTL * c , a logic extending CTL * with modalities to represent and reason about social commitments and their actions. We present a reduction technique that formally transforms the problem of model checking ACTL * c to the problem of model checking GCTL * (an extension of CTL * with action formulae). We prove that the reduction technique is sound and we fully implement it on top of the CWB-NC model checker to automatically verify the NetBill protocol, a motivated and specified example in the proposed specification language. We also apply the proposed technique to check the compliance of another protocol: the Contract Net protocol with given properties and report and discuss the obtained results. We finally develop a new symbolic algorithm to perform model checking dedicated to the proposed logic.

Simulation Modelling Practice and Theory, 2015

Though modeling and verifying Multi-Agent Systems (MASs) have long been under study, there are still challenges when many different aspects need to be considered simultaneously. In fact, various frameworks have been carried out for modeling and verifying MASs with respect to knowledge and social commitments independently. However, considering them under the same framework still needs further investigation, particularly from the verification perspective. In this article, we present a new technique for model checking the logic of knowledge and commitments (CTLKC + ). The proposed technique is fully-automatic and reduction-based in which we transform the problem of model checking CTLKC + into the problem of model checking an existing logic of action called ARCTL. Concretely, we construct a set of transformation rules to formally reduce the CTLKC + model into an ARCTL model and CTLKC + formulae into ARCTL formulae to get benefit from the extended version of NuSMV symbolic model checker of ARCTL. Compared to a recent approach that reduces the problem of model checking CTLKC + to another logic of action called GCTL ⁄ , our technique has better scalability and efficiency. We also analyze the complexity of the proposed model checking technique. The results of this analysis reveal that the complexity of our reduction-based procedure is PSPACE-complete for local concurrent programs with respect to the size of these programs and the length of the formula being checked. From the time perspective, we prove that the complexity of the proposed approach is P-complete with regard to the size of the model and length of the formula, which makes it efficient. Finally, we implement our model checking approach on top of extended NuSMV and report verification results for the verification of the NetBill protocol, taken from business domain, against some desirable properties. The obtained results show the effectiveness of our model checking approach when the system scales up.

Lecture Notes in Computer Science, 2011

We investigate the problem of verifying commitment protocols that are widely used to regulate interactions among cognitive agents by means of model checking. We present a new logic-based language to specify commitment protocols, which is derived from extending CTL * with modalities for social commitments and associated actions. We report on the implementation of the NetBill protocol-a motivated and specified example in the proposed language-using three model checkers (MCMAS, NuSMV, and CWB-NC) and compare the experimental results obtained.

2007

Commitment protocols have been proposed as a basis for modeling and enacting interactions among agents, such as those needed to carry out business processes. A central idea is that protocols would be developed and shared via libraries, and refined and composed to produce protocols that serve specific needs. Success in this program, therefore, presupposes that individual protocols and their compositions can be formally verified with respect to the properties of interest. This paper outlines an approach for verifying the correctness of commitment protocols and their compositions that exploits the well-known software engineering technique of model checking.

Computation

Innumerable industries now use multi-agent systems (MASs) in various contexts, including healthcare, security, and commercial deployments. It is challenging to select reliable business protocols for critically important safety-related systems (e.g., in healthcare). The verification and validation of business applications is increasingly explored concerning multi-agent systems’ group social commitments. This study explains a novel extended reduction verification method to model-check business applications’ critical specification rules using action restricted computation tree logic (ARCTL). In particular, we aim to conduct the verification process for the CTLGC logic using a reduction algorithm and show its effectiveness to handle MASs with huge models, thus, showing its importance and applicability in large real-world applications. To do so, we need to transform the CTLGC model to an ARCTL model and the CTLGC formulas into ARCTL formulas. Thus, the developed method was verified with ...

2012

Social commitments have been extensively and effectively used to represent and model business contracts among autonomous agents having competing objectives in a variety of areas (e.g., modeling business processes and commitmentbased protocols). However, the formal verification of social commitments and their fulfillment is still an active research topic. This paper presents CTLC + that modifies CTLC, a temporal logic of commitments for agent communication that extends CTL logic to allow reasoning about communicating commitments and their fulfillment. The verification technique is based on reducing the problem of model checking CTLC + into the problem of model checking ARCTL (the combination of CTL with action formulae) and the problem of model checking GCTL * (a generalized version of CTL * with action formulae) in order to respectively use the extended NuSMV symbolic model checker and the CWB-NC automata-based model checker as a benchmark. We also prove that the reduction techniques are sound and the complexity of model checking CTLC + for concurrent programs with respect to the size of the components of these programs and the length of the formula is PSPACE-complete. This matches the complexity of model checking CTL for concurrent programs as shown by Kupferman et al. We finally provide two case studies taken from business domain along with their respective implementations and experimental results to illustrate the effectiveness and efficiency of the proposed technique. The first one is about the NetBill protocol and the second one considers the Contract Net protocol.

2006 Canadian Conference on Electrical and Computer Engineering, 2006

In this paper, we propose a new model checking algorithm for verifying dialogue game protocols (DGP) for multi-agent communication. These protocols are specified as transition systems in which transitions are labeled with communicative acts. Our underlying logic (SC-CTL*) used to specify the properties to be verified extends CTL* by adding action formulae. the actions we deal with are actions that agents perform on social commitments when communicating. The verification method is based on the translation of SCCTL* formulae into a variant of alternating tree automata called Alternating Büchi Tableau Automata (ABTA). Our algorithm explores the product graph of the protocol and the ABTA representing the formula to be verified. The nodes of the product graph are signed according to the type of the formula (with or without negation). We propose a set of tableau inference rules for specifying the translation procedure. The efficiency of our algorithm is due to the fact that it uses only one depth-first search instead of two. Our algorithm explores directly the product graph using the sign of the nodes. This algorithm is an on-the-fly efficient algorithm.

IEEE Intelligent Systems, 2015

Developing and implementing a model checker dedicated to conditional commitment logic with the user interface are urgent requirements for determining whether agents comply with their commitment protocols.

Fundamenta Informaticae, 2017

Social approaches have been put forward to define semantics for intelligent agent communication messages and to tackle the shortcomings of mental approaches. Formal semantics of those social approaches can be model checked as they are focused on public behaviors instead of private mental states. Social conditional commitments are essential concepts in social approaches that can effectively model agent communications. However, conditional commitments exclusively are not able to model agent communication actions, the cornerstone of the fundamental agent communication theory, namely speech act theory. These actions provide mechanisms for dynamic interactions and enable designers to track the evolution of active conditional commitments. From the perspective of model checking, we need to define a formal and computationally grounded semantics for relevant social actions that can directly be applied to active conditional commitments. This manuscript describes a new symbolic model checker, SMC4AC, developed and implemented to automate the verification of interaction among intelligent agents. SMC4AC is the result of developing a new symbolic model checking algorithm devoted to CTLC α , a combination of CTL and new temporal modalities to represent and reason about conditional commitments