Strömungstechnische Modellversuche an einem Winderhitzer mit außenstehendem Brennschacht und Vergleich der Ergebnisse mit Betriebsmessungen

Strömungstechnische Untersuchungen an einem Winderhitzermodell. Entwicklung eines mathematischen Winderhitzermodells. Das Berechnungsprogramm. Ergebnisse und Vergleich mit Betriebsmessungen. Schlußfolgerungen.     

Model-based testing of stochastically timed systems

Innovations in Systems and Software Engineering - Many systems are inherently stochastic: they interact with unpredictable environments or use randomised algorithms. Classical model-based testing...     

Prototyping realistic programming languages based on formal specifications

The specification of realistic programming languages is difficult and expensive. One approach to make language specification more attractive is the development of techniques and systems for the generation of language–specific software from specifications. To contribute to this approach, a tool–based framework with the following features is presented: It supports new techniques to specify more language aspects in a static fashion. This improves the efficiency of generated software. It provides powerful interfaces to generated software components. This facilitates the use of these components as parts of language–specific software. It has a rather simple formal semantics. In the framework, static semantics is defined by a very general attribution technique enabling e.g. the specification of flow graphs. The dynamic semantics is defined by evolving algebra rules, a technique that has been successfully applied to realistic programming languages. After providing the formal background of the framework, an object–oriented programming language is specified to illustrate the central specification features. In particular, it is shown how parallelism can be handled. The relationship to attribute grammar extensions is discussed using a non-trivial compiler problem. Finally, the paper describes new techniques for implementing the framework and reports on experiences made so far with the implemented system. Received: 20 November 1995 / 20 January 1997     

Invited Paper: UHP‐lamp systems for projection applications

Abstract— Projection systems have found widespread use in conference rooms and other professional applications during the last decade and are now entering the home‐TV market with considerable pace. Projectors as small as about one liter are nowadays able to deliver a screen flux of several thousand lumens and are, with a system efficacy of more than 10 lm/W, the most‐efficient display system realized today. Because such highly efficient projectors employ microdisplays as light valves, short‐arc lamps are a key component in realizing these properties. The introduction of the UHP‐lamp system by Philips in 1995 can be identified as one of the key enablers for the commercial success of projection systems. The ultra‐high‐performance (UHP) lamp concept features outstanding arc luminance, a well‐suited spectrum, long life, and excellent flux maintenance. For the first time, it combines a very‐high‐pressure mercury‐discharge lamp having an extremely short and stable arc length with a regenerative chemical cycle that keeps the discharge walls free from blackening, leading to lifetimes of over 10,000 hours. In this review, the most important aspects of the UHP concept that enabled its success in the projection market are described, followed by a discussion of some recent additions to the UHP‐product portfolio.     

Dynamic LL(k) parsing

A new class of context-free grammars, called dynamic context-free grammars, is introduced. These grammars have the ability to change the set of production rules dynamically during the derivation of some terminal string. The notion of LL() parsing is adapted to this grammar model. We show that dynamic LL() parsers are as powerful as LR() parsers, i.e. that they are capable to analyze every deterministic context-free language while using only one symbol of lookahead. Received: 24 August 1994 / 5 January 1996     

An efficient statistical model checker for nondeterminism and rare events

Statistical model checking avoids the state space explosion problem in verification and naturally supports complex non-Markovian formalisms. Yet as a simulation-based approach, its runtime becomes excessive in the presence of rare events, and it cannot soundly analyse nondeterministic models. In this article, we present modes: a statistical model checker that combines fully automated importance splitting to estimate the probabilities of rare events with smart lightweight scheduler sampling to approximate optimal schedulers in nondeterministic models. As part of the Modest Toolset, it supports a variety of input formalisms natively and via the Jani exchange format. A modular software architecture allows its various features to be flexibly combined. We highlight its capabilities using experiments across multi-core and distributed setups on three case studies and report on an extensive performance comparison with three current statistical model checkers.

     

The convergence of mobile data phones,consumer electronics,and wallets: Lessons from Japan

Japan is leading the world with the adoption of new mobile data services such as Internet services and with a resulting boost in data ARPU (average revenue per user). In the development of these services, many functions have been integrated into mobile handsets, which has resulted in a convergence of, so far, separate consumer electronic devices. This article addresses the following questions: What are the drivers of this process? What could European players, in particular the European policymakers do to catch up? According to our research, a major driver of the process in Japan is tough competition among operators, which in turn is driven by factors such as competition in mobile radio infrastructure. The author arrives at the following conclusions for European policies: (1) There should be more awareness of the Japanese lead, e.g., of the crucial role of Internet push e-mail. (2) Europe could benefit from more operators willing to bear the risk of introducing new technologies. (3) For a successful introduction of infrastructure competition, it could make sense to make spectrum bands available with European-wide licenses.     

Ventilation of passenger car cabins: comparison of experimental data and numerical calculations

The complex flow in the interior of a passenger car cabin is measured and calculated in a Reynolds number range of practical importance. It turns out that the mean flow field compares quite well, even in minor details. But, experiments and calculations deviate considerably as far as turbulent quantities are concerned. The situation is analysed by a closer look to the physics of the flow field. From this, conclusions are drawn why the k−ɛ model applied here might be inappropriate for the flow field under consideration.     

Quantification of the thaumatin-like kiwi allergen by a monoclonal antibody-based ELISA

Thaumatin-like proteins (TLPs) have been established as a new family of fruit and pollen allergens. The aim of this study was to develop a two-site ELISA for the quantification of the thaumatin-like kiwi allergen (Act d 2) in kiwifruit extracts and kiwifruit-containing food products. Genomic DNA (gDNA) of Act d 2 was amplified and the deduced amino acid sequence was determined to obtain a primary structure. Act d 2 purified from kiwifruit extract by HPLC was identified by Edman degradation and MS. Balb/c mice were immunized with Act d 2 for the production of mAbs by hybridoma technology. The optimized ELISA measured Act d 2 concentrations ranging from 0.2 to 9.0 ng/mL, with intra- and interassay coefficients of variation of 3.65 and 10.44%, respectively. The developed ELISA is a useful method for the quantification of the thaumatin-like kiwi allergen in kiwifruit extracts as well as the allergen level in kiwifruit-containing food products. It may be a helpful analytical tool for the evaluation of the stability (integrity) of fruit allergen extracts for in vitro diagnosis.