Coupling Measurement of Interorganizational Processes Based on Petri Nets

This paper describes the application of Real-Time Maude to the formal modeling, simulation, and model checking analysis of the NORM multicast protocol standard being developed by the Internet Engineering Task Force. Because of its size and sophistication, real-time features, and the need to model and analyze subcomponents of NORM both in isolation and in combination, NORM poses a set of challenging problems for its formal specification and analysis. Our formal modeling and analysis efforts made us aware of ambiguities, inconsistencies, and cases of under-specification in the informal specification of NORM. Our work indicates that formal methods can successfully be applied by non-experts during the development of advanced Internet protocol standards.

An introduction to the modeling of business information systems, with processes formally modeled using Petri nets. This comprehensive introduction to modeling business-information systems focuses on business processes. It describes and demonstrates the formal modeling of processes in terms of Petri nets, using a well-established theory for capturing and analyzing models with concurrency. The precise semantics of this formal method offers a distinct advantage for modeling processes over the industrial modeling languages found in other books on the subject. Moreover, the simplicity and expressiveness of the Petri nets concept make it an ideal language for explaining foundational concepts and constructing exercises. After an overview of business information systems, the book introduces the modeling of processes in terms of classical Petri nets. This is then extended with data, time, and hierarchy to model all aspects of a process. Finally, the book explores analysis of Petri net models to detect design flaws and errors in the design process. The text, accessible to a broad audience of professionals and students, keeps technicalities to a minimum and offers numerous examples to illustrate the concepts covered. Exercises at different levels of difficulty make the book ideal for independent study or classroom use.

In this paper we revisit the topic of dialogue grammars at the illocutionary force level and present a new approach to the formal modelling, evaluation and comparison of these models based on recursive transition networks. Through the use of appropriate tools such finite-state grammars can be formally analysed and validated against empirically collected corpora. To illustrate our approach we show: (a) the construction of human-human dialogue grammars on the basis of recently collected natural language dialogues in joint-task situations; and (b) the evaluation and comparison of these dialogue grammars using formal methods. This work provides a novel basis for developing and evaluating dialogue grammars as well as for engineering corpus-tailored dialogue managers which can be verified for adequacy.KeywordsDialogue SystemDialogue ModelDialogue ManagementDialogue StructureDialogue ParticipantThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

A general stochastic hybrid process (GSHP) is a mathematical formalism that covers most of the requirements posed by the modelling of complex operations, such as time dependencies, multi-dimensional continuous as well as discrete processes, discontinuities, randomness and model uncertainties. In addition, it is possible to study GSHP by using stochastic analysis methodologies, thereby empowering it with powerful mathematical properties. This guarantees unambiguous simulation possibility of the model and allows speeding up this simulation while keeping the model properties intact. However, using GSHP to construct a model of a complex operation is not easy. To support the modelling and the subsequent verification both by mathematical and by multiple operational domain experts, a supporting graphical modelling formalism is desired. Petri nets have shown to be useful for developing models of various complex applications. Typical Petri net features are concurrency and synchronisation mechanism, hierarchical and modular construction, and natural expression of causal dependencies, in combination with graphical and analytical representations. The aim of this thesis is to combine the strengths of Petri net modelling formalisms and those of GSHP. First, dynamically coloured Petri nets (DCPN) are developed, and proof of equivalence is provided with piecewise deterministic Markov processes, which is a particular class of GSHP. Next, DCPN are extended to stochastically and dynamically coloured Petri nets (SDCPN), and proof of equivalence is provided with GSHP. Subsequently, SDCPN are extended to SDCPN with interconnection mapping types (SDCPNimt) and proof of equivalence is provided with both SDCPN and GSHP. It is shown with illustrative air transport examples that these three classes of Petri net are very effective when it comes to the compositional modelling of operations consisting of many distributed components that behave and interact in a dynamic way with many uncertainties. With the equivalence relations between these formalisms, the properties and strengths of the various approaches are combined. The many applications of the approach developed in this thesis, executed at NLR and beyond, show that both the approach and its combined strengths are acknowledged and supported by practice.

In recent years, many firms have prioritized both pay equity (i.e., closing pay gaps associated with target groups such as women and racial minorities) and equitable representation (i.e., ensuring these target groups are fairly represented across a firm’s hierarchy). We use formal modeling and simulations to show how efforts to close pay gaps across multiple groups can undermine equitable representation. Specifically, our analysis suggests that pressure for pay equity creates a cost-based financial incentive to enact a subtle form of tokenism: A firm may minimize the cost of closing pay gaps if it maintains a workforce with a small number of minority women whom it pays well in order to compensate for underpaying larger numbers of majority women and minority men who resemble each other in terms of job attributes and personal qualifications. A firm can avoid these outcomes if it focuses on ensuring that employees from target groups are equitably rewarded for job attributes and personal qualifications rather than minimizing cost. But an equitable-rewards approach can be substantially more expensive than a cost-minimization approach, especially if pay gaps are larger in high-wage jobs or if there are many target groups. We conclude by offering testable empirical predictions and recommending a practical solution, namely to include terms for intersectional categories (e.g., minority women) in the regressions used to estimate pay gaps. Supplemental Material: The online appendix is available at https://doi.org/10.1287/orsc.2023.18306 .

Security analysis of the open banking account and transaction API protocol

The research on modeling and simulation of complex biological systems is getting more important in Systems Biology. In this respect, we have developed Hybrid Function Petri net (HFPN) that was newly developed from existing Petri net because of their intuitive graphical representation and their capabilities for mathematical analyses. However, in the process of modeling metabolic, gene regulatory or signal transduction pathways with the architecture, we have realized three extensions of HFPN, (i) an entity should be extended to contain more than one value, (ii) an entity should be extended to handle other primitive types, e.g. boolean, string, (iii) an entity should be extended to handle more advanced type called object that consists of variables and methods, are necessary for modeling biological systems with Petri net based architecture. To deal with it, we define a new enhanced Petri net called hybrid functional Petri net with extension (HFPNe). To demonstrate the effectiveness of the enhancements, we model and simulate with HFPNe four biological processes that are diffcult to represent with the previous architecture HFPN.

The inference of performance models from low-level location tracking traces provides a means to gain high-level insight into customer and/or resource flow in complex systems. In this context our earlier work presented a methodology for automatically constructing Petri Net performance models from location tracking data. However, the capturing of synchronisation between service centres – the natural expression of which is one of the most fundamental advantages of Petri nets as a modelling formalism – was not explicitly supported. In this paper, we introduce mechanisms for automatically detecting and incorporating synchronisation into our existing methodology. We present a case study based on synthetic location tracking data where the derived synchronisation detection mechanism is applied.KeywordsLocation TrackingPerformance ModellingData MiningGeneralised Stochastic Petri Nets

A modular Petri net to modeling and scenario analysis of a network of road traffic signals

We present a formal OpenFlow-based network programming language (OF) including various flow rules, which can not only describe the behaviors of an individual switch, but also support to model a network of switches connected in the point-to-point topology. Besides, a topology-oriented operational semantics of the proposed language is explored to specify how the packet is processed and delivered in the OpenFlow-based networks. Based on the formal framework, we also propose an approach to detect potential security threats caused by the conflict of dynamic flow rules imposed by dynamic OpenFlow applications.

This paper is concerned with the formal modelling and simulative analysis of an energy-efficient MAC protocol for gossip-based wireless sensor networks. This protocol is a variant of classical slotted Aloha in which the number of active TDMA slots is dynamically changed depending on the number of neighbours of a node. We provide a formal model of this protocol, and analyse energy consumption under the signal-to-interference plus noise ratio (SINR) radio model. We propose an amendment of the distributed slotted Aloha protocol by a simple dynamic power assignment scheme, and show that this significantly reduces the energy consumption (30%) and speeds up the message transmission.

How to model the inter-organizational dynamic business process is becoming a focus. Two typical inter-organizational dynamic business process patterns are presented. Then, from the view of business rules, a decision-making behavioral rule description method is proposed based on context to model the inter-organizational dynamic behaviors. The method underlines the central position of the role and combines the way of state-driven and event-driven. It defines the decision-making behavior clearly, so that it can be more convenient to describe the knowledge-intensive inter-organizational dynamic business process. Finally, the proposed decision-making behavioral rule description method is applied to describe the two dynamic business process patterns. The application results show that proposed method satisfies the characteristics of the inter-organizational dynamic business process.

Because of the complexity of metabolic networks and their regulation, formal modelling is a useful method to improve the understanding of these systems. An essential step in network modelling is to validate the network model. Petri net theory provides algorithms and methods, which can be applied directly to metabolic network modelling and analysis in order to validate the model. The metabolism between sucrose and starch in the potato tuber is of great research interest. Even if the metabolism is one of the best studied in sink organs, it is not yet fully understood. We provide an approach for model validation of metabolic networks using Petri net theory, which we demonstrate for the sucrose breakdown pathway in the potato tuber. We start with hierarchical modelling of the metabolic network as a Petri net and continue with the analysis of qualitative properties of the network. The results characterize the net structure and give insights into the complex net behaviour.

Verification of behavioral soundness for artifact-centric business process model with synchronizations

In recent years, more and more challenges concerning the modeling of new and complex business process systems have emerged. E-learning business process is one of those systems which are based on documents. Modeling documents and their interactions with tasks in the same process, called document driven workflows, has not been widely represented. We focus on security issues by modeling time as an extension of such systems and discuss some constraints. There are different approaches for modeling those temporal aspects in workflow systems. Since Petri Nets are known for their capability and flexibility in modeling complex systems, we propose a Colored Petri Net and emphasize the use of Time Petri Nets to model workflow management systems based on documents with time constraints. We illustrate our model on a running example of e-learning process.