05 Fakultät Informatik, Elektrotechnik und Informationstechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6
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Item Open Access Languages, methods, and tools for software specification(1989) Ludewig, JochenSpecification systems consist of methods, languages, and tools; the languages may be more or less formal. In this paper, the general ideas of semi-formal specification systems are presented, and some examples are shown.Item Open Access Computer-aided safety analysis of computer-controlled systems : a case example(2000) Biegert, UweComputer controlled systems consist of a complex interaction between technical process, human task and software. For the development of safety critical systems new method are required, which not only consider one of these parts of a computer-controlled system. In this paper a qualitative modeling method is presented. The method is called SQMA, Situationbased Qualitative Modeling and Analysis and it origin goes back to Qualitative Reasoning. First, all parts of a system are modeled separated and then combined to a unique model of a computer-controlled system. With this qualitative model a computer supported hazard analysis can be realised.Item Open Access Modelling the quality economics of defect-detection techniques(2006) Wagner, StefanThere are various ways to evaluate defect-detection techniques. However, for a comprehensive evaluation the only possibility is to reduce all influencing factors to costs. There are already some models and metrics for the cost of quality that can be used in that context. These models allow the structuring of the costs but do not show all influencing factors and their relationships. This paper proposes an analytical model for the economics of defect-detection techniques that can be used for analysis and optimisation of the usage of such techniques. In particular we analyse the sensitivity of the model and how the model can be applied in practice.Item Open Access Process model for the development of system requirements specifications for railway systems(2002) Bitsch, FriedemannIn this paper a process model for the development of system requirements specifications for railway systems is introduced. Demands of the approval of system requirements specifications, which arise from recent European railway standards, are taken into account. The aim is to obtain a system specification, which is unambiguous and easy to understand for all parties involved and in which safety aspects are considered in detail. Correlations between the development of a precise system specification, the performance of safety relevant correctness checks and the performance of risk analysis are presented. Especially the identification, specification and formalisation of safety requirements are treated with regard to correctness checks referred to safety aspects by using model checking. It is also demonstrated how different techniques of risk analysis can be supported by a system model in diagrams of the Unified Modelling Language (UML). This work has been developed in close co-operation with the Institute of Railway Systems Engineering and Traffic Safety (IfEV), Technical University of Braunschweig, Germany within the scope of the project SafeRail (see http://www.ias.uni-stuttgart.de/projekte/saferail/).Item Open Access Software quality models : purposes, usage scenarios and requirements(2009) Deißenböck, Florian; Juergens, Elmar; Lochmann, Klaus; Wagner, StefanSoftware quality models are a well-accepted means to support quality management of software systems. Over the last 30 years, a multitude of quality models have been proposed and applied with varying degrees of success. Despite successes and standardisation efforts, quality models are still being criticised, as their application in practice exhibits various problems. To some extent, this criticism is caused by an unclear definition of what quality models are and which purposes they serve. Beyond this, there is a lack of explicitly stated requirements for quality models with respect to their intended mode of application. To remedy this, this paper describes purposes and usage scenarios of quality models and, based on the literature and experiences from the authors, collects critique of existing models. From this, general requirements for quality models are derived. The requirements can be used to support the evaluation of existing quality models for a given context or to guide further quality model development.Item Open Access CASE - eine kritische Übersicht(1989) Ludewig, JochenCASE ist aus dem Bedürfnis entstanden, den Prozeß der Software-Entwicklung durch Werkzeuge so zu unterstützen, daß die Produktivität gesteigert und die Qualität erhöht wird. Solche Werkzeuge sind auf der Basis moderner Rechner und Betriebssysteme möglich. Für die Interessenten ist es allerdings nicht leicht, die seriösen Produktinformationen von den überzogenen Werbesprüchen zu unterscheiden. Der Beitrag zielt zunächst darauf ab, das Wort CASE mit einem klaren Begriff zu verbinden. Der Zusammenhang zwischen Werkzeugen und Methoden wird ausführlich diskutiert. Weitere Schwerpunkte sind eine Übersicht der Werkzeuge, die unter den Begriff CASE fallen, eine Zusammenstellung der wichtigsten Anforderungen, eine Klassifikation von Werkzeugausstattungen und eine Diskussion ungelöster Probleme heutiger Werkzeuge. Einige Prognosen für die zukünftige Entwicklung des Software Engineerings schließen den Vortrag ab.Item Open Access Alte und neue Sprachkonzepte: Einstufung und Bewertung(1990) Ludewig, JochenDie "4th Generation Languages" entsprechen dem Katalog einer Fertighausfabrik. Lösungen können aus vorhandenen Komponenten schnell und billig zusammengesetzt werden - oder sie sind nicht möglich. Die Stärken liegen also in Geschwindigkeit und Kosten von Standardlösungen, die Schwächen in der mangelnden Flexibilität bei speziellen Problemen, insbesondere auch bei der Erweiterung vorhandener Software-Systeme.Item Open Access Trends in picture communication(1993) Speidel, JoachimIn the past years significant progress was made with digital transmission of audiovisual services and most interesting trends are visible for the future. Such applications encompass interactive services, like videoconferencing, ISDN-videophone, storage of moving video and audio in computers or on CD, e.g. for multimedia applications. For distribution services, there is an unbroken trend from TV to HDTV. Strong emphasis is on compressed digital video even for transmission to the home.Item Open Access Sichere Automatisierungssysteme mit Hilfe qualitativer Modellierung und quantitativer Risikobewertung(2000) Biegert, UweFür die Sicherheitsanalyse von Prozessautomatisierungssystemen ist es notwendig, alle Systembestandteile zu betrachten. Im Beitrag wird ein Modell vorgestellt, bei dem der technische Prozess, die Automatisierungssoftware und menschliche Bedieneingriffe qualitativ beschrieben werden. Aus den einzelnen Modellen und deren Wechselbeziehungen werden Situationen berechnet, die das mögliche Verhalten des Prozessautomatisierungssystems beschreiben. Im Beitrag wird gezeigt, wie eine Risikobewertung der berechneten Situationen nach VDI/VDE 3542 realisiert werden kann. Mit Hilfe der Quantifizierung des Risikos können konkrete Aussagen bezüglich des Grenzrisikos eines Prozessautomatisierungssystems gemacht werden.Item Open Access Vorlesungen, Prüfungen und Seminare in Software Engineering an der Universität Stuttgart(1992) Ludewig, Jochen-