R.T. Denton

Bio: R.T. Denton is an academic researcher from Lehigh University. The author has contributed to research in topics: Process architecture & Stochastic Petri net. The author has an hindex of 1, co-authored 1 publications receiving 14 citations.

Timed Petri nets and their application to communication protocol specification

Abstract: A generalized timed Petri net representation is defined and several time Petri net models compared. By introducing a new way to include a time variable in the Petri net and the firing rules, the authors realized a new timed Petri net that includes the other two principal types of timed Petri nets. This new timed Petri net seems to take a more general form than other types of time Petri nets defined so far. Therefore, complex systems are expected to be modeled with it. The authors present a model to represent a timer in order to model real communication systems properly. An example is given in which the timed Petri net representation and the timer model are applied to a communication protocol. With the results provided, communication protocols involving timers and transmission errors can be modeled. >

Charging Information Collection Modeling and Analysis of GPRS Networks

Abstract: Charging is one of the most important functionalities in a telecommunication service system In a general packet radio service (GPRS) wireless network, the load of charging information flow depends on the intensity of call traffic and the size of charging records During busy hours, the GPRS network might not be able to transfer charging records on a timely basis if new charging records are generated too fast On the other hand, when a call happens, the related charging information must be collected and transferred to the billing system If a failure of the data link occurs, a secondary data link must be employed to transfer the charging information However, this redundant operation might result in charging information duplication This paper formally addresses these two issues A timed Petri net model is built to support the analysis of the charging system performance versus various factors when the system works in the normal status, which, in particular, gives the maximum supportable busy hour call attempts of the GPRS network The Petri net approach is also used to model and verify the correctness of the redundancy operation in case a connection failure occurs

Verification of heterogeneous multi-agent system using MCMAS

Abstract: The focus of the paper is how to model autonomous behaviours of heterogeneous multi-agent systems such that it can be verified that they will always operate within predefined mission requirements and constraints. This is done by using formal methods with an abstraction of the behaviours modelling and model checking for their verification. Three case studies are presented to verify the decision-making behaviours of heterogeneous multi-agent system using a convoy mission scenario. The multi-agent system in a case study has been extended by increasing the number of agents and function complexity gradually. For automatic verification, model checker for multi-agent systems (MCMAS) is adopted due to its novel capability to accommodate the multi-agent system and successfully verifies the targeting behaviours of the team-level autonomous systems. The verification results help retrospectively the design of decision-making algorithms improved by considering additional agents and behaviours during three steps of sce...

Model checking for decision making behaviour of heterogeneous multi-agent autonomous system

Abstract: An autonomous system has been widely applied for various civil/military research because of its versatile capability of understanding high-level intent and direction of a surrounding environment and targets of interest. However, as autonomous systems can be out of control to cause serious loss, injury, or death in the worst case, the verification of their functionalities has got increasing attention. For that reason, this study is focused on the verification of a heterogeneous multi-agent autonomous system. The thesis first presents an overview of formal methods, especially focuses on model checking for autonomous systems verification. Then, six case studies are presented to verify the decision making behaviours of multi-agent system using two basic scenarios: surveillance and convoy. The initial system considered in the surveillance mission consists of a ground control system and a micro aerial vehicle. Their decision-making behaviours are represented by means of Kripke model and computational tree logic is used to specify the properties of this system. For automatic verification, MCMAS (Model Checker for Multi-Agent Systems) is adopted due to its novel capability to accommodate the multi-agent system. After that, the initial system is extended to include a substitute micro aerial vehicle. These initial case studies are then further extended based on SEAS DTC exemplar 2 dealing with behaviours of convoy protection. This case study includes now a ground control system, an unmanned aerial vehicle, and an unmanned ground vehicle. The MCMAS successfully verifies the targeting behaviours of the team-level unmanned systems. Reversely, these verification results help retrospectively improve the design of decision-making algorithms by considering additional agents and behaviours during four steps of scenario modification. Consequently, the last scenario deals with the system composed of a ground control system, two unmanned aerial vehicles, and four unmanned ground vehicles with fault-tolerant and communications relay capabilities. In conclusion, this study demonstrates the feasibility of model checking algorithms as a verification tool of a multi-agent system in an initial design stage. Moreover, this research can be an important first step of the certification of multi-agent autonomous systems for the domains of robotics, aerospace and aeronautics. To My beloved father, mother, my handsome husband, and my lovely daughter

Modeling and simulation of hybrid dynamical systems with generalized differential Petri nets

Abstract: There has been considerable interest in the modeling and simulation of hybrid dynamic systems (HDS). As an effective modeling tool of discrete event dynamic systems, Petri nets have a dual nature of a graphical tool and a mathematical object. In this paper, an extension of Petri net named generalized differential Petri nets (GDPN) is proposed to model HDS that have a combination of discrete-event evolution and continuous state evolution. Differential place and differential transition defined by Demongodin et al. (1998) are used to model the numeral simulation of the continuous dynamic process, and the weights defined on the directed arcs that connects the differential transitions and places are extended from real numbers to real matrices. The marking of differential place are also enlarged from real numbers to real vectors. Then the evolution rules and modeling method of HDS with GDPN are introduced. Two examples are used to illustrate the modeling power of GDPN in HDS.

Flexible agent protocols via temporal linear logic

Abstract: Multi-agent systems have emerged as a new field that addresses issues among distributed, interconnected and intelligent systems such as conflicts of interests, global constraints, and sharing of resources. Our research addresses an important aspect of mul