Siekiant maksimizuoti organizacijos pelną ir pagerinti jos veiklos rezultatus reikia efektyviai išnaudoti visus organizacijoje vykstančius verslo procesus. Tai padaryti galima naudojant įvairias verslo procesų valdymui skirtas kompiuterizuotas informacines sistemas. Projektavimo tikslas – sukurti ir aprašyti statinius ir dinaminius organizacijoje vykstančius procesus. Verslo procesams projektuoti ir analizuoti kuriant informacines sistemas, ypač jeigu jos didelės, reikia specialių projektavimo metodologijų ir priemonių, kurios šiuos procesus palengvintų, padarytų lengviau suvokiamais ir paspartintų darbą. Darbe išanalizuoti verslo procesų projektavimo būdai kuriant informacines sistemas: Petri tinklai, UML ir hibridinis Petri tinklų ir UML projektavimo metodas, pateikti jų aprašymai, savybės, galimybės. Taip pat išanalizuota organizacijose vykstantys verslo procesai. Bene daugiausia dėmesio skirta į rezultatyvumo ir žinių bei informacijos valdymo procesą, kadangi nuo jų priklauso organizacijos veiklos rezultatai. Organizacija projektuojama pradedant nuo bazinio - rezultatyvumo proceso. Todėl teorinių tyrimų aprašymo dalyje nagrinėjama pasirinkto rezultatyvumo verslo proceso projektavimas aprašytais Petri tinklų, UML bei hibridiniu metodais. Eksperimentinių tyrimų dalyje pasirinkta organizacija UAB „Proringas“, išanalizuoti joje veikiantys verslo procesai, sumodeliuotos skirtingų procesų valdymo sistemos, kurios sujungtos ir projektuotos trimis analizuojamais metodais. Metodai... [toliau žr. visą tekstą] / For maximising profit of organization and increasing its efficiency of activities must be used all business processes used in organization. The purpose of designing – to create and describe static and dynamic processes in organization. For projecting and analysing business processes while created information systems it is needed special modelling methodologies and tools that would make easier and more understandable those processes and would increase efficiency of work. There is analysed business processes design in this work while are created information systems: Petri-Net, UML and hybrid Petri-Net and UML design project methods, listed their descriptions, characteristics and possibilities. Also there are analysed business processes that take place in organization. Specialized attitude to information resources managing suppose demand of business system information, its usage and value by addressing adequate order for software. According the management position it must be coordination of data and information processing capabilities with creative person capabilities and technologies. Organization designed starting from processes and from them must be designed efficiency process. So in theoretical part it is analysed by chosen efficiency business process design described by Petri-Net and UML methods. In the part of experimental research selected organization - Joint stock company Proringas, analised business processes in it, modelled business processes that takes part in it... [to full text]

The purpose of the research is to create traffic optimal adjustment methods and algorithms based on the theory of Petri nets. To investigate the functionality of created algorithms.

In Canada, access to magnetic resonance imaging (MRI) examination is limited with an outcome of long patient waiting time. It is reported that the current median waiting time for MRI examination in Saskatoon is almost double the target for waiting time, which may aggravate the disease. This research is towards reducing the waiting time of patients for MRI examination in Canada by applying an improved management. As a first step of this effort, a comprehensive model of MRI booking and serving system is needed. The city of Saskatoon was taken as an example and the MRI booking and serving system in the city was studied. The common tools (queuing theory, system dynamics (SD) and discrete event dynamics simulation (DES)) were compared and it is found that DES is more suitable, in particular Petri nets (PNs), deemed to be the best choice for the purpose of this thesis. The model in this research was constructed on the basis of Hierarchical Coloured Petri nets (HCPNs), a combination of two extended PNs: Coloured PNs (CPNs) and Hierarchical PNs (HPNs). The model is able to simulate and predict patients' waiting times. Given that the structure of the model developed by HCPNs is still too complex, two extensions to CPNs, Ordered CPNs (OCPNs) and Prioritized HCPNs (PHCPNs), were proposed in this study to reduce the complexity of the model. Validation of the model was performed using the data of Saskatoon Health Region - Royal University Hospital. The results have shown that the proposed model can effectively describe the real system. The model has potential applications in decision-making for the selection of an optimal booking strategy to shorten waiting time and in the prediction of possible waiting time of the system in the future, which may assist MRI administrators in the management of medical resources and may greatly improve the quality of MRI service.

In this thesis, I/O signal recognizers, called VIRTUALBLOCKS, are synthesized to interface with a SYSTEM UNDER TEST (SUT). Methods for automated synthesis of virtualblocks allow us to simulate environment interfaces with SUT and also perform fault detection on SUT. Such methods must be able to recognize incoming sequences of signals from SUT, and upon the signal recognition determine the proper outgoing sequences of signals to SUT. We characterize our systems into four distinctive systems: system under test, AUXILIARY SYSTEM, controller and external environment. The auxiliary system is represented as a form of condition system Petri net (virtualblocks) and interacts with SUT along with the interaction among the controller and the external environment. Fault detection is performed by subsystems called DETECTBLOCKS synthesized from the virtualblocks. We present construction procedures for virtualblocks andamp; detectblocks and discuss the notion of LEGALITY and DETECTABILITY. Finally, we illustrate our approach using a model of a scanner control unit.

The current thesis considers the issue of state estimation of condition systems, a form of petri net with signal inputs and outputs. In previous research the problem of unobservability due to progress confusion was identified, in the presence of which state estimation is not possible. Here we introduce the notion of Time Condition Systems", a class of condition systems that uses timing information from condition models to overcome state estimation problem caused by progress confusion. To make use of the timing information in the plant model, a procedure called Exploded Time Plant" is synthesized. This procedure makes the plant model an observable model. It is proved that this procedure does not alter the structural and temporal behavior of the plant model and the plant maintains its integrity. The time plant(s) and the corresponding Exploded time plant(s) are subsequently used to develop observer(s) and controller(s) for Time condition models.

This thesis deals with the identification of automated discrete event systems (DES) operating in an industrial context. In particular the work focuses on the systems composed by a plant and a programmable logic controller (PLC) operating in a closed loop- the identification consists in obtaining an approximate model expressed in interpreted Petri nets (IPN) from the observed behaviour given under the form of a single sequence of input-output vectors of the PLC. First, an overview of previous works on identification of DES is presented as well as a comparative study of the main recent approaches on the matter. Then the addressed problem is stated- important technological characteristics of automated systems and PLC are detailed. Such characteristics must be considered in solving the identification problem, but they cannot be handled by previous identification techniques. The main contribution in this thesis is the creation of two complementary identification methods. The first method allows constructing systematically an IPN model from a single input-output sequence representing the observable behaviour of the DES. The obtained IPN models describe in detail the evolution of inputs and outputs during the system operation. The second method has been conceived for addressing large and complex industrial DES- it is based on a statistical approach yielding compact and expressive IPN models. It consists of two stages- the first one obtains, from the input-output sequence, the reactive part of the model composed by observable places and transitions. The second stage builds the non observable part of the model including places that ensure the reproduction of the observed input-output sequence. The proposed methods, based on polynomial-time algorithms, have been implemented in software tools, which have been tested with input-output sequences obtained from real systems in operation. The tools are described and their application is illustrated through two case studies.

The development process of mechatronic control systems often relies on physical prototypes to test the interactions between the control software and mechanical components. However, the logistics of synchronizing a concurrent development process and the risks of integrating only partially completed sub-systems often limits effective prototyping. The consequent lack of feedback can lead to overly complex and unreliable systems which may have to undergo expensive re-designs. The interactions between mechanical systems and control software can also be recreated artificially by combining a hybrid modelling language with computer graphics technology. A dynamic 3D environment can generate sensor telemetry for input to a control system, which in turn alters the state of the environment through virtual actuators. This kind of simulation allows engineers to explore a larger design space early during the development process without committing significant resources to physical prototypes. This dissertation introduces a method for simulating mechatronic systems using Petri Nets and Scene Trees. The following chapters formally define the modelling language and illustrate the software architecture and user interface of a novel simulation development environment. The research is validated through qualitative reasoning and by demonstrating a simulation that detects design flaws in a mechatronic system which may have otherwise lead to expensive redesigns in the physical system.

Thesis (PhD)--University of South Australia, 1998

The Resource Reservation Protocol (RSVP) is one of the proposals of the Internet Engineering Task Force (IETF) for conveying Quality of Service (QoS) related information in the form of resource reservations along the communication path. The RSVP specification (i.e. Request for Comments 2205) provides a narrative description of the protocol without any use of formal techniques. Thus, some parts of the document may be ambiguous, difficult to understand, and imprecise. So far, RSVP implementations have provided the only mechanism for validating. The cost for fixing errors in the protocol found in the implementation can be high. These disadvantages together with the fact that RSVP is complex make it a good target for formal specification and verification. This thesis formally defines the RSVP Service Specification, models RSVP using a formal method known as Coloured Petri Nets (CPNs) and attempts to verify the model. The following steps summarise the verification process of RSVP. Firstly, the RSVP service specification is derived from the protocol description and modelled using CPNs. After validating the model, the service language, which defines all the possible service primitive occurrence sequences, is generated from the state space of the model by using automata reduction techniques that preserve sequences. Secondly, RSVP is modelled using CPNs. The model is analysed for a set of behavioural properties. They include general properties of protocols, such as correct termination, and a set of new properties defined in this thesis, which are particular to RSVP. The analysis is based on the state space method. The properties are checked by querying the state graph and checking reachability among multiple nodes of its associated Strongly Connected Component (SCC) graph. As a first step, we analyse RSVP under the assumption of a perfect medium (no loss or duplication) to ensure that protocol errors are not hidden by rare events of the medium. The state space is reduced to obtain the sequences of service primitives allowed by RSVP known as the protocol language. Then, the protocol language is compared with the service language to determine if they are equivalent. The desired properties of RSVP are proved to be satisfied by the RSVP CPN model, so that the features of RSVP included in the CPN model operate as expected under our modelling and analysis assumptions. Also, the language analysis results show that RSVP service primitive occurrence sequences generated by the RSVP model are included in the proposed model of the service specification. However, some service primitive occurrence sequences generated from the service specification model are not in the protocol language. These sequences were analysed. There is strong evidence to suggest that these sequences would also appear in the protocol if the capacity of the medium in the RSVP model was marginally increased. Unfortunately, the standard reachability analysis tools would not handle this case, due to state space explosion. / Thesis (PhD)--University of South Australia, 2003

Thesis (Ph. D.), Memorial University of Newfoundland, 1999. / Bibliography: p. 131-137.