DEPENDABILITY MODELLING AND EVALUATION |
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Contents (preliminary) Audience Preparatory meeting Registration Overview of the seminar Instructor Assistant Literature Audience This seminar addresses Master or Bachelor students in Computer Science. Preparatory meeting There will be a preparatory meeting on April 14 at 17:30 in E 1 3, room 528. Everyone interested in this seminar should attend the meeting. Registration If you want to participate in the Seminar, please apply at our Course Management System. You may have to sign up for a student account first. For questions or comments please contact the teaching assistant. Overview of the seminar In this seminar, the modelling and evaluation of dependable systems is discussed. As an introduction, we copy a paragraph from the book:
(ed.). Wien : Springer, 1992. (Dependable computing and fault-tolerant systems ; 5) Dependability is defined as the trustworthines of a computer system such that reliance can justifiably be placed on the service it delivers. Dependable has several aspects:
To evaluate the dependability of a system we need to first create a model of the system. This model of course has to approximate the real system. But we must also be able to analyze the model to find out the dependability of the system. In this seminar we will discuss a number of different formalisms used to model dependable systems. We have divided the formalisms into three categories. Suggest reading material for the different topics is listed here. Dependability specific models focus on modeling structures and phenomena that often appear in dependable models, such as the use of spare components and the propagation of faults through a system. The advantage of dependability specific models is that they are usually easy to use and compositional. Models are built by connecting predefined building blocks. The disadvantage is then that we are restricted to whatever building blocks are provided to us. Also dependability specific models can usually not be analyzed directly. Instead they are often transformed to a low-level mathematical model. Examples of dependability specific formalisms are:
Low-level models describe the behavior of systems in great detail. They are usually based on automata theory and Markovian stochastics. The advantage of this is that these models are usually very expressive and can be readily analyzed. The disadvantage is that it can be difficult to create a low-level model of a large system because the model will also be very large. A number of low-level formalisms are given below:
Architectural approaches focus on the structure of the system being described. The idea is to start with a very abstract view of the system and then to refome this view to lower levels of abstraction. Analysis of architectural models is based on the one-model-multiple-analysis idea. The goal is to have a single model of a system on which we can perform many different types of analysis. The advantage of architectural models that they are usually very well structured and can be used in sophisticated software/hardware development methods. The disadvantage is that it is often quite difficult to analyze architectural models, which is also very true for the dependability aspects of such models. Below are listed a few architectural methodologies which allow the specification of dependability features:
Instructor
Assistant Literature Here, you will find some proposed literature for the seminar. You have to use at least one source in addition to the ones proposed by us. If you find some proposal is not sensible, please consult with your teacher.
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Dependable Systems & Software Group | Department of Computer Science | Universität des Saarlandes |