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Dive into the research topics where Manfred Broy is active.

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Featured researches published by Manfred Broy.


ACM Transactions on Software Engineering and Methodology | 2007

A formal model of services

Manfred Broy; Ingolf H. Krüger; Michael Meisinger

Service-oriented software systems rapidly gain importance across application domains: They emphasize functionality (services), rather structural entities (components), as the basic building block for system composition. More specifically, services coordinate the interplay of components to accomplish specific tasks. In this article, we establish a foundation of service orientation: Based on the Focus theory of distributed systems (see Broy and Stølen [2001]), we introduce a theory and formal model of services. In Focus, systems are composed of interacting components. A component is a total behavior. We introduce a formal model of services where, in contrast, a service is a partial behavior. For services and components, we work out foundational specification techniques and outline methodological development steps. We show how services can be structured and how software architectures can be composed of services and components. Although our emphasis is on a theoretical foundation of the notion of services, we demonstrate utility of the concepts we introduce by means of a running example from the automotive domain.


Theoretical Computer Science | 1986

A theory for nondeterminism, parallelism, communication, and concurrency

Manfred Broy

An applicative language is introduced for representing concurrent programs and communicating systems in the form of mutually recursive systems of nondeterministic equations for functions and streams. Mathematical semantics is defined by associating particular fixed points with such systems. These fixed points are chosen using a combination of several complete partial orderings. Operational semantics is described in the form of term rewriting rules, consistent with the mathematical semantics. It represents data-driven reduction semantics for usual expressions and data-driven data flow semantics in the case of recursive stream equations. So the language allows to treat the basic semantic notions of nondeterminism, parallelism, communication, and concurrency for multiprogramming in a completely formal, applicative framework. In particular, it provides a semantic theory for networks of loosely coupled, nondeterministic, communicating, stream processing functions. Finally, the relationship of the presented language to partial recursive functions and nonconventional computational models such as data flow and reduction machines is shown.


Journal of the ACM | 1997

Compositional refinement of interactive systems

Manfred Broy

We introduce a method to describe systems and their components by functional specification techniques. We define notions of interface and interaction refinement for interactive systems and their components. These notions of refinement allow us to change both the syntactic (the number of channels and sorts of messages at the channels) and the semantic interface (causality flow between messages and interaction granularity) of an interactive system component. We prove that these notions of refinement are compositional with respect to sequential and parallel composition of system components, communication feedback and recursive declarations of system components. According to these proofs, refinements of networks can be accomplished in a modular way by refining their compponents. We generalize the notions of refinement to refining contexts. Finally, full abstraction for specifications is defined, and compositionality with respect to this abstraction is shown, too.


rex workshop on stepwise refinement of distributed systems models formalisms correctness | 1989

Functional Specification of Time Sensitive Communicating Systems

Manfred Broy

A formalism for the functional specification of time sensitive communicating systems and their components is outlined. The specification method is modular w.r.t. sequential composition, parallel composition, and communication feedback. Nondeterminism is included by underspecification. The application of the specification method to timed communicating functions is demonstrated. The relationship between nondeterminism and timed systems is investigated. Forms of reasoning are considered. The alternating bit protocol is used as a running example.


Science of Computer Programming | 2010

Multifunctional software systems: Structured modeling and specification of functional requirements

Manfred Broy

This paper deals with the structured specification of interface behavior of multifunctional systems, which are systems that offer a variety of functions for different purposes and use cases. It introduces a theory and first concepts of a methodology for the identification, structured modeling, and formalization of functional requirements of multifunctional systems. Service hierarchies specify multifunctional systems in terms of their provided sub-functions called services together with their mutual relationships and dependencies. A service hierarchy describes the functionality of multifunctional systems in a structured way. Each service is specified independently and the specification is added to the service hierarchy. Modes help to specify the feature interactions and by that functional dependencies between the services. The approach is based on the Focus theory for modeling interface behavior and services.


Archive | 1989

Constructive Methods in Computing Science

Manfred Broy

This paper explains the notion of propositions as types within the context of Per Martin-LMs theory of types. The relationship between constructive and classical logic is also discussed. In addition mention is made of the connection between the natural-deduction-style reasoning used here and the theory of preorders discussed by Hoare elsewhere in this volume. The material in these notes is adapted from an excerpt of the forthcoming book entitled Constructive Type Theory and is reproduced here with the permission of its publishers, Prentice/Hall International, Inc. NATO ASI Series, Vol. F 55 Constructive Methods in Computing Science Edited by M. Broy


ACM Transactions on Software Engineering and Methodology | 1993

Functional specification of time-sensitive communicating systems

Manfred Broy

A formal model and a logical framework for the functional specification of time-sensitive communicating systems and their interacting components are outlined. The specification method is modular with respect to sequential composition, parallel composition, and communication feedback. Nondeterminism is included by underspecification. The application of the specification method to timed communicating functions is demonstrated. Abstractions from time are studied. In particular, a rational is given for the chosen concepts of the functional specification technique. The relationship between system models based on nondeterminism and system models based on explicit time notions is investigated. Forms of reasoning are considered. The alternating bit protocol is used as a running example.


Archive | 1989

Towards a Design Methodology for Distributed Systems

Manfred Broy

A methodology for the specification and design of distributed systems is outlined. It follows the classical patterns of system design developed for sequential systems starting from an abstract specification going through a number of design decisions and finally leading to a distributed system composed of communicating and cooperating programs. A fully formal framework is provided such that all steps can be performed within the formal framework by transformations or at least be formally verified.


international symposium organized jointly with working group provably correct systems on formal techniques in real time and fault tolerant systems | 1994

Specification and Refinement of Finite Dataflow Networks - a Relational Approach

Manfred Broy; Ketil Stølen

We specify the black box behavior of dataflow components by characterizing the relation between their input and their output histories. We distinguish between three main classes of such specifications, namely time independent specifications, weakly time dependent specifications and strongly time dependent specifications. Dataflow components are semantically modeled by sets of timed stream processing functions. Specifications describe such sets by logical formulas. We emphasize the treatment of the well-known fair merge problem and the Brock/Ackermann anomaly. We give refinement rules which allow specifications to be decomposed modulo a feedback operator.


formal methods | 1998

A Functional Rephrasing of the Assumption/Commitment Specification Style

Manfred Broy

The assumption/commitment (also called rely/guarantee) style has been advocated for the specification of interactive components of distributed systems. It suggests the structuring of specifications into assumptions about the behavior of the components environment and into commitments that are fulfilled by the component, provided the environment fulfills these assumptions. One of its motivations is to achieve modularity (also called compositionality) for state transition specifications of system components. Another reason for writing specifications in this format lies in proof rules that refer to this format. We define the assumption/commitment formats for functional system specifications. In particular, we work out a canonical decomposition of system specifications following the assumption/commitment format into safety and liveness aspects. We demonstrate the format of assumption/commitment specifications by a number of examples. Finally, we discuss the methodological significance of the assumption/commitment format in the stepwise development of specifications.

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