Timed data flow diagrams

Traditional Data Flow Diagrams (DFD\u27s) are the cornerstone of the software development methodology known as Structured Analysis (SA), and they are probably the most widely used specification technique in industry today. DFD\u27s are popular because of their graphical representation and their hierarchical structure. Thus, they are well-suited for users with non-technical backgrounds and are commonly used to depict the static structure of information flow in a system. Numerous attempts to formalize DFD\u27s have appeared in the technical literature. We focus on the Formalized Data Flow Diagrams (FDFD\u27s) developed by Coleman, Wahls, Baker, and Leavens;This dissertation analyzes and extends FDFD\u27s with respect to their usefulness in specifying the qualitative and quantitative properties of real systems. Prior to this dissertation, there existed no well-founded knowledge about the computational power of FDFD\u27s nor any formal model in FDFD\u27s of the timing behavior of real systems;The dissertation is organized as a collection of five independent papers. Briefly, the main results of each paper are as follows: (i) Reduced FDFD\u27s are Turing equivalent. (ii) Stores, persistent flows, tests for empty flows, and infinite domains are not essential for FDFD\u27s. (iii) Subclasses of FDFD\u27s are equivalent to known subclasses of FIFO Petri Nets, immediately furnishing the decidability results for subclasses of FIFO Petri Nets to the corresponding subclasses of FDFD\u27s. (iv) A general stochastic model of time for FDFD\u27s (called Timed Data Flow Diagrams--TDFD\u27s) is defined, allowing not only a description of the relative likelihoods of various execution times, but also descriptions of the possible joint firing behavior of transitions. (v) An aggregation principle can be used for an efficient stochastic analysis of periodic TDFD\u27s with Markovian transition times;The results in this dissertation provide a firm theoretical foundation for further advances in Computer Science and Statistics, leading to practical and expressive tools for the specification and analysis of real systems

Value-Oriented Design of Service Coordination Processes: Correctness and Trust

The rapid growth of service coordination languages creates a need for methodological support for coordination design. Coordination design differs from workflow design because a coordination process connects different businesses that can each make design decisions independently from the others, and no business is interested in supporting the business processes of others. In multi-business cooperative design, design decisions are only supported by all businesses if they contribute to the profitability of each participating business. So in order to make coordination design decisions supported by all participating businesses, requirements for a coordination process should be derived from the business model that makes the coordination profitable for each participating business. We claim that this business model is essentially a model of intended value exchanges. We model the intended value exchanges of a business model as e3 -value value models and coordination processes as UML activity diagrams. The contribution of the paper is then to propose and discuss a criterion according to which a service coordination process must be correct with respect to a value exchange model. This correctness is necessary to gain business support for the process. Finally, we discuss methodological consequences of this approach for service coordination process design

A Model-Driven CASE tool for developing and verifying regulated open MAS

[EN] This paper describes a CASE tool for developing complex systems in which heterogeneous and autonomous agents may need to coexist in a complex social and legal framework. Model-Driven Technologies are used to integrate the design of systems of this kind with the verification of the models and with the generation of executable code from these models. The verification module is based on model-checking techniques to check the coherence of a modeled legal context at design time is presented and it is exemplified with a case studyThis work is partially supported by the TIN2008-04446, TIN2009-13839-C03-01, PROMETEO 2008/051 projects, CONSOLIDER INGENIO 2010 under grant CSD2007-00022 and FPU grant AP2007-01276 awarded to Emilia Garcia.Garcia Marques, ME.; Giret Boggino, AS.; Botti, V. (2013). A Model-Driven CASE tool for developing and verifying regulated open MAS. Science of Computer Programming. 78(6):695-704. https://doi.org/10.1016/j.scico.2011.10.009S69570478

DAG-Based Attack and Defense Modeling: Don't Miss the Forest for the Attack Trees

This paper presents the current state of the art on attack and defense modeling approaches that are based on directed acyclic graphs (DAGs). DAGs allow for a hierarchical decomposition of complex scenarios into simple, easily understandable and quantifiable actions. Methods based on threat trees and Bayesian networks are two well-known approaches to security modeling. However there exist more than 30 DAG-based methodologies, each having different features and goals. The objective of this survey is to present a complete overview of graphical attack and defense modeling techniques based on DAGs. This consists of summarizing the existing methodologies, comparing their features and proposing a taxonomy of the described formalisms. This article also supports the selection of an adequate modeling technique depending on user requirements

Web Engineering for Workflow-based Applications: Models, Systems and Methodologies

This dissertation presents novel solutions for the construction of Workflow-based Web applications: The Web Engineering DSL Framework, a stakeholder-oriented Web Engineering methodology based on Domain-Specific Languages; the Workflow DSL for the efficient engineering of Web-based Workflows with strong stakeholder involvement; the Dialog DSL for the usability-oriented development of advanced Web-based dialogs; the Web Engineering Reuse Sphere enabling holistic, stakeholder-oriented reuse

Knowledge Representation Concepts for Automated SLA Management

Outsourcing of complex IT infrastructure to IT service providers has increased substantially during the past years. IT service providers must be able to fulfil their service-quality commitments based upon predefined Service Level Agreements (SLAs) with the service customer. They need to manage, execute and maintain thousands of SLAs for different customers and different types of services, which needs new levels of flexibility and automation not available with the current technology. The complexity of contractual logic in SLAs requires new forms of knowledge representation to automatically draw inferences and execute contractual agreements. A logic-based approach provides several advantages including automated rule chaining allowing for compact knowledge representation as well as flexibility to adapt to rapidly changing business requirements. We suggest adequate logical formalisms for representation and enforcement of SLA rules and describe a proof-of-concept implementation. The article describes selected formalisms of the ContractLog KR and their adequacy for automated SLA management and presents results of experiments to demonstrate flexibility and scalability of the approach.Comment: Paschke, A. and Bichler, M.: Knowledge Representation Concepts for Automated SLA Management, Int. Journal of Decision Support Systems (DSS), submitted 19th March 200