Robotic systems have been developed in every field where a further progress was constricted due to the human limitations in terms of speed, precision, fatigue, repeatability, strength, safety etc. One of the pioneer f...
The probability of failure rate and error rate are important indicators for the assessment of applications for high-speed communication systems. The paper presents causes of faults and theoretical and practical method...
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We present novel concepts, technologies and potentials of optical data communication, especially for future computer architectures. The WDM (wavelength division multiplexing) and the optical wiring technologies are ex...
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The international standard IEC/61508 provides the developer with guidelines for the design and implementation of safety related systems according to this standard. This standard states qualitative and quantitative cri...
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ISBN:
(纸本)9781424435890
The international standard IEC/61508 provides the developer with guidelines for the design and implementation of safety related systems according to this standard. This standard states qualitative and quantitative criteria in order to judge a safety related system in such a way that safety critical applications can be implemented. This paper details a quantitative criterion which is the probability of failure on low demand, known as PFD. After an introduction into this topic, the principle steps to calculate the probability of failure with the help of reliability block diagrams for different hardware architecture will be detailed and presented. The PFD-equations will be derived for a 1oo1 architecture with the help of MacLaurin series.
The standard IEC/EN61508 provides the developer with guidelines to develop and implement safety related systems according to the international standard. The standard supplies qualitative and quantitative criteria to e...
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This paper revisits a problem that was identified by Kramer and Magee: placing a system in a consistent state before and after runtime changes. We show that their notion of quiescence as a necessary and sufficient con...
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Because they are easy to create and modify, low fidelity prototypes are commonly used in early evaluations of user interface designs. Designers typically use either pen-and-paper or various computer-based tools to cre...
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ISBN:
(纸本)1595936424
Because they are easy to create and modify, low fidelity prototypes are commonly used in early evaluations of user interface designs. Designers typically use either pen-and-paper or various computer-based tools to create and test low fidelity prototypes;however, our informal analyses of these existing technologies indicate that they do not optimally support the two key, complementary tasks of (a) prototype creation and (b) wizard of oz testing. To address this problem, we have been developing WOZ Pro (Wizard of Oz Prototyper), a pen-based software environment for the quick and easy creation and testing of low fidelity user interface prototypes. We are designing WOZ Pro to be as easy to use as pen-and-paper, but to hold key advantages over pen-and-paper and existing computer-based tools. When designing interface screens in WOZ Pro, designers can easily (a) propagate a design change to other related screens, and (b) specify the set of screens that are reachable from a given screen. In a wizard of oz test, WOZ Pro reduces the cognitive load on the wizard by allowing navigation only to those next screens that are valid. We are planning a controlled experiment to compare WOZ Pro against paper-and-pencil along several measures in a set of prototype creation and evaluation tasks.
Developing security-critical applications is very difficult and the past has shown that many applications turned out to be erroneous after years of usage. For this reason it is desirable to have a sound methodology fo...
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Developing security-critical applications is very difficult and the past has shown that many applications turned out to be erroneous after years of usage. For this reason it is desirable to have a sound methodology for developing security-critical e-commerce applications. We present an approach to model these applications with the Unified Modeling Language (UML) [1] extended by a UML profile to tailor our models to security applications. Our intent is to (semi-) automatically generate a formal specification suitable for verification as well as an implementation from the model. Therefore we offer a development method seamlessly integrating semi-formal and formal methods as well as the implementation. This is a significant advantage compared to other approaches not dealing with all aspects from abstract models down to code. Based on this approach we can prove security properties on the abstract protocol level as well as the correctness of the protocol implementation in Java with respect to the formal model using the refinement approach. In this paper we concentrate on the modeling with UML and some details regarding the transformation of this model into the formal specification. We illustrate our approach on an electronic payment system called Mondex [10]. Mondex has become famous for being the target of the first ITSEC evaluation of the highest level E6 which requires formal specification and verification.
We elaborate on reasoning in contemporary (semi) automatic parallelizing refactoring. As the main contribution we summarize contemporary approaches and show that all attempts to reason in parallelization thus far, hav...
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We elaborate on reasoning in contemporary (semi) automatic parallelizing refactoring. As the main contribution we summarize contemporary approaches and show that all attempts to reason in parallelization thus far, have amounted to local code analysis given data and control dependencies. We conclude that, by retaining this perspective only, parallelization continues to exploit merely a subset of the reasoning methods available today and is likely to remain limited. To address this problem we suggest to expand the local analyses, such that, they take seriously relations between individual local parallelizing transformations. We argue that such a coupling allows to process sparser parallelizable constructs, such as, producer-consumer coordination. We identify questions to be addressed to put this principle into action and report on-going work on (reasoning) mechanisms able to support this.
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