Termination Criteria for Model Transformation

Nowadays the usage of model transformations in software engineering has become widespread. Considering current trends in software development such as model driven development (MDD), there is an emerging need to develop model manipulations such as model evolution and optimisation, semantics definition, etc. If a model transformation is described in a precise way, it can be analysed lateron. Models, especially visual models, can be described best by graphs, due to their multi-dimensional extension. Graphs can be manipulated by graph transformation in a rule-based manner. Thus, we specify model transformation by graph transformation. This approach offers visual and formal techniques in such a way that model transformations can be subjects to analysis. Various results on graph transformation can be used to prove important properties of model transformations such as its functional behaviour, a basic property for computations. Moreover, certain kinds of syntactical and semantical consistency properties can be shown on this formal basis

Análisis de rendimiento de diagramas de secuencia mediante redes Petri

Este Trabajo Fin de Grado implementa un mecanismo para analizar rendimiento en fases tempranas en el desarrollo software mediante técnicas de Ingeniería de Prestaciones Software (en inglés, SPE, Software Performance Engineering). Este tipo de desarrollo software se centra en el análisis de comportamiento dinámico de los sistemas software para obtener datos de su rendimiento. Esto se hace muy difícil con el uso generalizado del estándar UML (Unified Modelling Language) propuesto por OMG (Object Management Group). UML trata de estandarizar los diagramas del desarrollo software. Estos diagramas permiten un nivel de abstracción que proporciona una herramienta perfecta para el diseño de software. Sin embargo, estos diagramas son semi formales. Los diagramas semiformales son aquellos que nos permiten representar el software de forma más semejante al código, pero conserva un nivel de abstracción suficiente como para ser entendidos con facilidad tanto por personal cualificado como no cualificado. Estos diagramas por tanto están pensados para facilitar la comprensión y no tanto como para usarlos de forma activa en un análisis de rendimiento. Por esa razón, se han propuesto perfiles UML, como MARTE, que permiten añadir a estos diagramas información que posibilitan el análisis de rendimiento. En el caso de MARTE, proporciona unas estructuras de datos sobre el funcionamiento útiles para los análisis de prestaciones. A pesar de ello, la limitación que tenemos con UML y un perfil como MARTE unidos es que, por mucho que permitan la representación de parámetros para la mejor visualización y representación del diseño, no permiten hacer un análisis automático. Por ello, este TFG trata de cómo utilizar los diagramas UML, tan comúnmente utilizados hoy en día, para poder hacer un análisis de rendimiento que siente las bases de un diseño más eficiente desde una fase temprana del desarrollo. Para lograr esto, se harán uso de las propiedades de las SPN (Stochastic Petri Nets). Este tipo particular de grafos dirigidos permite representar sistemas temporizados ya que son un caso particular de las cadenas de Márkov. Esta característica hace ideales a las SPN para representar sistemas software, ya sean distribuidos, paralelos o concurrentes. Esta formalización, por tanto, aparte de permitirnos representar un sistema software, nos permite además analizar su comportamiento dinámico. Por ello, para hacer un análisis de rendimiento de un diagrama UML se necesita transformarlo a una red de Petri. Este TFG trata uno de los diagramas dinámicos más utilizados que es el diagrama de secuencia. Estos diagramas sirven para representar las comunicaciones entre los distintos módulos del sistema a lo largo del tiempo. Por tanto, es muy útil el análisis de un diagrama de secuencia para conocer el comportamiento dinámico de un sistema. Por último, una herramienta muy extendida para el desarrollo software es Eclipse, por ello, en este TFG se muestra el desarrollo de un plugin para Eclipse que analiza el rendimiento de los diagramas de secuencia por medio de una transformación a redes Petri

The Impact of Petri Nets on System-of-Systems Engineering

The successful engineering of a large-scale system-of-systems project towards deterministic behaviour depends on integrating autonomous components using international communications standards in accordance with dynamic requirements. To-date, their engineering has been unsuccessful: no combination of top-down and bottom-up engineering perspectives is adopted, and information exchange protocol and interfaces between components are not being precisely specified. Various approaches such as modelling, and architecture frameworks make positive contributions to system-of-systems specification but their successful implementation is still a problem. One of the most popular modelling notations available for specifying systems, UML, is intuitive and graphical but also ambiguous and imprecise. Supplying a range of diagrams to represent a system under development, UML lacks simulation and exhaustive verification capability. This shortfall in UML has received little attention in the context of system-of-systems and there are two major research issues: 1. Where the dynamic, behavioural diagrams of UML can and cannot be used to model and analyse system-of-systems 2. Determining how Petri nets can be used to improve the specification and analysis of the dynamic model of a system-of-systems specified using UML This thesis presents the strengths and weaknesses of Petri nets in relation to the specification of system-of-systems and shows how Petri net models can be used instead of conventional UML Activity Diagrams. The model of the system-of-systems can then be analysed and verified using Petri net theory. The Petri net formalism of behaviour is demonstrated using two case studies from the military domain. The first case study uses Petri nets to specify and analyse a close air support mission. This case study concludes by indicating the strengths, weaknesses, and shortfalls of the proposed formalism in system-of-systems specification. The second case study considers specification of a military exchange network parameters problem and the results are compared with the strengths and weaknesses identified in the first case study. Finally, the results of the research are formulated in the form of a Petri net enhancement to UML (mapping existing activity diagram elements to Petri net elements) to meet the needs of system-of-systems specification, verification and validation

Analysis and Optimization of Mobile Business Processes

Mobility of workers and business processes rapidly gains the attention of businesses and business analysts. A wide variety of definitions exists for mobile business processes. This work considers a type of business processes concerned with the maintenance of distributed technical equipment as, e.g., telecommunication networks, utility networks, or professional office gear. Executing the processes in question, workers travel to the location where the equipment is situated and perform tasks there. Depending on the type of activities to be performed, the workers need certain qualifications to fulfill their duty. Especially in network maintenance processes, activities are often not isolated but depend on the parallel or subsequent execution of other activities at other locations. Like every other economic activity, the out- lined mobile processes are under permanent pressure to be executed more efficiently. Since business process reengineering (BPR) projects are the common way to achieve process improvements, business analysts need methods to model and evaluate mobile business processes. Mobile processes challenge BPR projects in two ways: (i) the process at- tributes introduced by mobility (traveling, remote synchronization, etc.) complicate process modeling, and (ii) these attributes introduce process dynamics that prevent the straightforward prediction of BPR effects. This work solves these problems by developing a modeling method for mobile processes. The method allows for simulating mobile processes considering the mobility attributes while hiding the complexity of these attributes from the business analysts modeling the processes. Simulating business processes requires to assign activites to workers, which is called scheduling. The spatial distribution of activities relates scheduling to routing problems known from the logistics domain. To provide the simula- tor with scheduling capabilities the according Mobile Workforce Scheduling Problem with Multitask-Processes (MWSP-MP) is introduced and analyzed in-depth. A set of neighborhood operators was developed to allow for the application of heuristics and meta-heuristics to the problem. Furthermore, methods for generating start solutions of the MWSP-MP are introduced. The methods introduced throughout this work were validated with real-world data from a German utility. The contributions of this work are a reference model of mobile work, a business domain independent modeling method for mobile business processes, a simulation environment for such processes, and the introduction and analysis of the Mobile Workforce Scheduling Problem with Multitask-Processes