A Model Driven Approach to the Analysis of Timeliness Properties

Abstract. The need for a design language that is rigorous but accessible and intuitive is often at odds with the formal and mathematical nature of languages used for analysis. UML and Petri Nets are a good example of this dichotomy. UML is a widely accepted modelling language capable of modelling the structural and behavioural aspects of a system. However UML lacks the mathematical foundation that is required for rigorous analysis. Petri Nets on the other hand have a strong mathematical base that is well suited for analysis of a system but lacks the appeal and ease-of-use of UML. Design in UML languages such as Sequence Diagrams and analysis in Petri Nets require on one hand some expertise in potentially two incompatible systems and their tools, and on the other a seamless transition from one system to the other. One way of addressing this impediment is to focus the software development mainly on the design language system and to facilitate the transition to the formal analysis by means of a combination of automation and tool support. The aim of this paper is to present a transformation system, which takes UML Sequence Diagrams augmented with time constraints and generates semantically equivalent Petri Nets that preserve the timing requirements. A case study on a small network is used in order to illustrate the proposed approach and in particular the design, the transformation and the analysis processes.

Model interoperability via model driven development

It is widely recognised that software development is a complex process. Among the factors that contribute to its inherent complexity is the gap between the design and the formal analysis domains. Software design is often considered a human oriented task while the analysis phase draws on formal representation and mathematical foundations. An example of this dichotomy is the use of UML for the software design phase and Petri Nets for the analysis; a separation of concerns that leads to the creation of heterogeneous models. Although UML is widely accepted as a language that can be used to model the structural and behavioural aspects of a system, its lack of mathematical foundations is seen as a serious impediment to rigorous analysis. Petri Nets on the other hand have a strong mathematical basis that is well suited for formal analysis; they lack however the appeal and the easeof-use of UML. A pressing concern for software developers is how to bridge the gap between these domains and allow for model interoperability and the integration of different toolsets across them, and thus reduce the complexity of the software development process. The aim of this paper is to present a Model Driven Development (MDD) model transformation which supports a seamless transition between UML and Petri Nets. This is achieved by model interoperability between UML Sequenc

A model driven approach to analysis and synthesis of sequence diagrams

Software design is a vital phase in a software development life cycle as it creates a blueprint for the implementation of the software. It is crucial that software designs are error-free since any unresolved design-errors could lead to costly implementation errors. To minimize these errors, the software community adopted the concept of modelling from various other engineering disciplines. Modelling provides a platform to create and share abstract or conceptual representations of the software system – leading to various modelling languages, among them Unified Modelling Language (UML) and Petri Nets. While Petri Nets strong mathematical capability allows various formal analyses to be performed on the models, UMLs user-friendly nature presented a more appealing platform for system designers. Using Multi Paradigm Modelling, this thesis presents an approach where system designers may have the best of both worlds; SD2PN, a model transformation that maps UML Sequence Diagrams into Petri Nets allows system designers to perform modelling in UML while still using Petri Nets to perform the analysis. Multi Paradigm Modelling also provided a platform for a well-established theory in Petri Nets – synthesis to be adopted into Sequence Diagram as a method of putting-together different Sequence Diagrams based on a set of techniques and algorithms

Proceedings Work-In-Progress Session of the 13th Real-Time and Embedded Technology and Applications Symposium

The Work-In-Progress session of the 13th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS\u2707) presents papers describing contributions both to state of the art and state of the practice in the broad field of real-time and embedded systems. The 17 accepted papers were selected from 19 submissions. This proceedings is also available as Washington University in St. Louis Technical Report WUCSE-2007-17, at http://www.cse.seas.wustl.edu/Research/FileDownload.asp?733. Special thanks go to the General Chairs – Steve Goddard and Steve Liu and Program Chairs - Scott Brandt and Frank Mueller for their support and guidance

Modelling and analysis of next generation home networks

As Home Networking grows over the next 20 years the need for accurate models for both the network and the hardware becomes apparent. In this work, these two areas are considered together to develop a combined hardware and network model for a HomePlug power line based network. This change of focus is important when the type of devices that will be running on tomorrow's home network is considered. It will have evolved from a simple network of PCs sharing an Internet connection to a large heterogeneous structure of embedded System-on-Chip devices communicating on a variety of linked network technologies.This work presents a novel combined hardware and network modelling tool that address the following areas: 1. Development of a system level model of a HomePlug power-line based network, including the fundamental network protocols, the SoC hardware and the physical channel. 2. Use the developed model to explore various system scenarios. 3. Development of alternative hardware algorithms within the design. The model developed uses a Discrete Event simulation method to allow designers to explore areas such as: 1. How does the networking hardware (i.e. the components on the SoC) interact, and what are the issues of changing the algorithms. 2. I low do the nodes on the network interact, as the traffic patterns are different to those found on traditional (office-based) networks, as there will be a greater amount of streaming media

Elektroninių paslaugų įgyvendinimo sprendimai

Monografijoje nagrinėjamos elektroninių paslaugų (toliau tekste – ir e. paslaugos) plėtros tendencijos, apžvelgiamos įvairios temos – nuo paprastųjų e. paslaugų infrastruktūros kūrimo iki sudėtingų išmaniųjų paslaugų technologinių sprendimų. Kuriant šiuolaikines dirbtinio intelekto sistemas svarbu, kad jos būtų naudingos vartotojams ir pritaikomos kintančiai aplinkai. Ypač daug dėmesio skiriama išmaniųjų paslaugų kūrimui ir vartotojų įpročių analizei, gyventojų gebėjimams įsisavinti teikiamas paslaugas. Svarbu, kad išmaniosios sistemos leistų daugelį paslaugų valdyti automatiškai, pritaikant jas konkretiems poreikiams. Viena iš tokių sistemų kūrimo sričių – adaptuotosios paslaugos ir nuolat kintantis jų pateikimas. Taip pat aktualu mažinti išteklių sąnaudas, teikti paslaugas tiesioginės kreipties režimu ir reikiamu laiku, kartu siekiant paslaugų kokybės ir kuo mažesnės paklaidų rizikos. Dirbtinio intelekto sistemose, adekvačiai įvertinant paklausą ir gebėjimus valdyti paslaugų teikimo procesus, siūlomos įvairias dalykines sritis siejančios kompiuterinės technologijos. Tai mokslai, susiję su biomedicina, psichologija, kompiuterių inžinerija, lingvistika ir kt

Route discovery schemes in Mobile Ad hoc Networks with variable-range transmission power

Broadcasting in MANETs is important for route discovery but consumes significant amounts of power that is difficult to renew for devices that rely heavily on batteries. Most existing routing protocols make use of a broadcast scheme known as simple flooding. In such an on-demand routing protocol (e.g. AODV) the source node originates a Route Request (RREQ) packet that is blindly rebroadcast via neighbouring nodes to all nodes in the network. Simple flooding leads to serious redundancy, together with contention, and collisions, which is often called the broadcast storm problem. This thesis proposes two improvement strategies: topology control (adjusting transmission power) and reduced retransmissions (reducing redundant rebroadcasts) to reduce energy consumption. For energy efficient route discovery the main idea is to reduce the energy consumed per broadcast during route discovery. An Energy Efficient Adaptive Forwarding Algorithm (called EEAFA) is proposed to reduce the impact of RREQ packet flooding in on-demand routing protocols. The algorithm operates in two phases: 1) Topology construction phase, which establishes a more scalable and energy efficient network structure where nodes can adjust their transmission power range dynamically, based on their local density. 2) A Forwarding Node Determination phase, that utilises network information provided by the constructed topology, where nodes independently decide to forward a RREQ packet or not without relying on GPS or any distance calculations. A further Enhanced EEAFA (called E-EEAFA) algorithm is also proposed, which combines two techniques: graph colouring and sectoring techniques. Graph colouring increases awareness at network nodes to improve the determination of a forwarding node, while the sectoring technique divides neighbours into different forwarding sectors. This helps to reduce overlap between forwarding nodes and select suitable nodes in each sector to forward RREQ packets. These techniques are employed in a distributed manner and collaborate to reduce the number of forwarding nodes, which thus reduces the volume of RREQ packets populating the network. These algorithms have been validated as effective by NS2 simulation studies that are detailed in the thesis