Papers by Klaudia Dussa-Zieger
Abstrac t \Ve compare the performance of two recently proposed distance-vector algorithms (Merlin... more Abstrac t \Ve compare the performance of two recently proposed distance-vector algorithms (Merlin-Segall and Extended Bellman-Ford) with a link-state algorithm (SPF), under varying fil e transfer workload. (Unlike the traditional distance-vector algorithms, these new distancevector algorithms do not suffer from long-lived loops .) Our comparison is done using a recently developed network simulator. NlaR.S. We consider both dynamic and static fil e transfer connections. and both uniform and hotspot distributions of source-sink pairs. Ou r conclusion is that Extended Bellman-Ford performs as well as SPF in terms of delay an d throughput. This suggests that distance-vector algorithms are appropriate for very large wide-area networks. since their space requirements are less than that of link-state algorithms. This work is supported in part by RADC and DARPA under contract F30602-90-C-0010 to i MIACS at th e University of Maryland, and by National Science Foundation Grant No. NCR 89-04590. The views, opinions , and/or findings contained in this report are those of the author(s) and should not be interpreted as representin g the official policies, either expressed or implied, of the Defense Advanced Research Projects Agency, RADC, o r the U .S. Government. Computer facilities were provided in part by NSF grant CCR-8811954 .
Functional Safety has become a vital property of many products and systems. There is a clear tren... more Functional Safety has become a vital property of many products and systems. There is a clear trend to move safety functions from pure mechanics into electronic control units. Therefore over the recent years, various standards have evolved describing the properties and certification criteria of safety-critical electronically controlled products and systems. In order for a particular product to be adapted to the requirements of different target markets, the integration of functional safety considerations according to the relevant standards into the complete product creation processes and organisations is essential. This integration requires special competencies that define the new job role of a Functional Safety Manager. This article gives an overview of these competency requirements in the context of the documentation of the first results, the targets, and the scope of the EU project SafEUr, which aims at putting in place a Europe-wide on-line training and certification program for functional safety managers according to the requirements of several industry sectors, as well as the experiences from research and practical safety engineering projects.
Journal of Parallel and Distributed Computing, 1999
In this paper, we consider a massively parallel system that is composed of heterogeneous processo... more In this paper, we consider a massively parallel system that is composed of heterogeneous processors, that is, processors with different processing power, and that combines the advantages of the SIMD and MIMD architectures. The heterogeneous mixed-mode (HeMM) execution model is composed of two main components, which operate in the well-known SIMD and MIMD paradigms. The main computing power comes from a component that is composed of a massive number of processors and operates in a data parallel manner. The other component is composed of a few (or even one) fast processors which operate in the MIMD paradigm. The operation of a small number of processors in an MIMD paradigm has been well demonstrated through actual systems. The processors in this component add flexibility to the execution of the parallel programs such that it adjusts to the changing parallelism of the program to enhance the performance. Based on this execution model we analyze the gains in performance that is obtainable by this new system. We show that substantial performance gains can be obtained by using the HeMM system.
Communications in Computer and Information Science, 2017
The paper describes the overall structure of Automotive SPICE and TestSPICE. It presents a compar... more The paper describes the overall structure of Automotive SPICE and TestSPICE. It presents a comparison between the processes in Automotive SPICE® and TestSPICE and then focuses on the testing processes and some specific test topics. The paper shows potential benefits of TestSPICE for the automotive industry. It deals with topics like test data management, test automation and test techniques, which are not or only roughly mentioned in Automotive SPICE. The paper also gives a short explanation of the agile extension of TestSPICE.
TOM is a registered trademark of Systeme Evolutif Limited Use of any trademarks in this report is... more TOM is a registered trademark of Systeme Evolutif Limited Use of any trademarks in this report is not intended in any way to infringe on the rights of the trademark holder.
Softwaretechnik-Trends, 2015
Mittlerweile hat die Erfolgsstory ISTQB® mehr als 40.000 ISTQB® Certified Tester in Deutschland h... more Mittlerweile hat die Erfolgsstory ISTQB® mehr als 40.000 ISTQB® Certified Tester in Deutschland hervorgebracht, wobei weltweit mehr als 350.000 ISTQB® Certified Tester zu verzeichnen sind (Stand: Juli 2015). Das German Testing Board (www.germantesting-board.info), ein Zusammenschluss von Fachexperten aus Industrie, Trainingsanbietern und Hochschulen für das Testen von Software und Systemen, hat nun eine Initiative gestartet, neben den ISTQB® CORE-Lehrplänen branchenund methodenspezifische Erweiterungen zu etablieren. Eine dieser Erweiterungen – CTFL®-CAST – wurde speziell für die Automotive-Branche aufgesetzt und soll die besonderen Anforderungen des Testens von E/E Systemen in diesem Bereich abdecken. Zielsetzung der zertifizierten Ausbildung ist es, ein Grundverständnis über die Besonderheiten beim Test von Steuergeräte-Software im Automobil zu vermitteln. Tester sollen in die Lage versetzt werden, fundiert Teststrategien abzuleiten, normenkonforme Testverfahren auszuwählen und Te...
Communications in Computer and Information Science, 2017
The paper presents the TestSPICE approach showing the content of the current version of TestSPICE... more The paper presents the TestSPICE approach showing the content of the current version of TestSPICE, the transition to Scalable TestSPICE and the agile extension of TestSPICE. In addition it describes the relationship of TestSPICE to the ISO Standard ISO/IEC/IEEE 29119 and the ISO/IEC 15504 family of process assessment standards. The ECQA SPI Manager training which supports the implementation of TestSPICE is also presented.
Software Reliability Growth Models assume that the application under test (AUT) is tested accordi... more Software Reliability Growth Models assume that the application under test (AUT) is tested according to its operational profile. However, examining the test practices at different industrial test laboratories this is often not the case. Instead, a systematic approach to testing is taken. The differences in systematic versus operational testing, in particular their effect on the failure count model, is the topic of this paper. After a detailed discussion of the advantages and disadvantages of systematic and operational testing, the hypergeometric failure model by Rivers and Vouk is presented. In our work problems in the original formulation of the model are resolved and the derivation of the continuous form is more stringent. A different approach to the interpretation of testing efficiency is taken. The model is applied to data collected during a test project at imbus AG and the results of the failure prediction are presented. The paper concludes with an outlook on further research activities. 1 Systematic vs. operational testing One possible way of testing software is using it according to its operational profile. This means that the operations- major system tasks of short duration with processing substantially different from other operations [9]-of the application under test (AUT) have to be determined together with their execution probabilities. Based on these probabilities the number of test cases is allocated to the different program functions. The testers should
this paper we present a genetic algorithm that determines the schedule of an application and the ... more this paper we present a genetic algorithm that determines the schedule of an application and the topology of the target multiprocessor system at the same time. In this context the genetic algorithm is used as a stochastic search algorithm. There are two basic methods to adapt a genetic algorithm to a given problem: namely to construct new genetic operators or to find a good genetic representation for feasible solutions. In [3] the main emphasis was placed on constructing a specialized genetic operator (i.e. a new crossing-over operator) which is exactly tailored for multiprocessor scheduling (with fixed topology). On the contrary, we chose a genetic algorithm with standard genetic operators and concentrate on the design of the genetic representation for schedule and topology. Since it is not feasible for an optimization algorithm to work directly with the program code or the hardware, appropriate models are introduced. The parallel program is modelled through a task graph. The task ...
Communications in Computer and Information Science, 2013
In the EU project SafEUr (518632-LLP-1-2011-1-AT-LEONARDO-LMP) the partnership developed a skill ... more In the EU project SafEUr (518632-LLP-1-2011-1-AT-LEONARDO-LMP) the partnership developed a skill set with learning objectives, training materials, and tools to teach and coach the implementation of IEC 61508 and ISO 26262. Automotive, Medical, and Nuclear industry gave inputs to the project. A group of above 20 multinational companies (SOQRATES www.soqrates.de) which also are active in automotive industry (some of them represent the largest suppliers in Automotive industry) organised reviews and trial courses with safety managers. This led to a defined set of skills and tools we expect from functional safety managers and functional safety engineers. In this paper we describe the results of SafEUr, the feedback we received from the collaboration with leading automotive industry and the next steps in 2013 to launch this schema with official certificates from end of 2013 onwards.
Communications in Computer and Information Science, 2012
Functional Safety has become a vital property of many products and systems. There is a clear tren... more Functional Safety has become a vital property of many products and systems. There is a clear trend to move safety functions from pure mechanics into electronic control units. Therefore over the recent years, various standards have evolved describing the properties and certification criteria of safety-critical electronically controlled products and systems. In order for a particular product to be adapted to the requirements of different target markets, the integration of functional safety considerations according to the relevant standards into the complete product creation processes and organisations is essential. This integration requires special competencies that define the new job role of a Functional Safety Manager. This article gives an overview of these competency requirements in the context of the documentation of the first results, the targets, and the scope of the EU project SafEUr, which aims at putting in place a Europe-wide on-line training and certification program for functional safety managers according to the requirements of several industry sectors, as well as the experiences from research and practical safety engineering projects.
Proceedings Euromicro Workshop on Parallel and Distributed Processing
Conformance testing of communication protocols has recently become a major issue in the context o... more Conformance testing of communication protocols has recently become a major issue in the context of 0%based standardization ofprotocols. The aim of conformance test-ing is to assure that a protocol fulfills an OS1 specijka-tion. In this paper; a perfarmance study is presented for a ...
Informatik-Fachberichte, 1991
ACM SIGCOMM Computer Communication Review, 1992
We compare the performance of two recently proposed distance-vector algorithms (Merlin-Segall and... more We compare the performance of two recently proposed distance-vector algorithms (Merlin-Segall and Extended Bellman-Ford) with a link-state algorithm (SPF), under varying file transfer workload. (Unlike the traditional distance-vector algorithms, these new distance-vector algorithms do not suffer from long-lived loops.) Our comparison is done using a recently developed network simulator. MaRS. We consider both dynamic and static file transfer connections, and both uniform and hotspot distributions of source-sink pairs. Our conclusion is that Extended Bellman-Ford performs as well as SPF in terms of delay and throughput. This suggests that distance-vector algorithms are appropriate for very large wide-area networks, since their space requirements are less than that of link-state algorithms.
ACM SIGCOMM Computer Communication Review, 1992
We have recently developed a discrete-event simulator. referred to as MaRS (Maryland Routin g Sim... more We have recently developed a discrete-event simulator. referred to as MaRS (Maryland Routin g Simulator). for studying routing systems. AIaRS provides a flexible platform for the evaluatio n and comparison of network routing algorithms. It has an optional graphical (l Window System) interface. It is implemented in C on a I-NI\ platform. (The event handling and user interfac e routines come from a network simulator developed at MIT->] .) MaIIS allows t lie user to define a network configuration. control its simulation. log the value s of selected parameters. and save. load. and modify network configurations. The schedulin g of events can be clone using random number generators. t race files. or both. MaRS has a
We examine two approaches to adaptive routing protocols for wide-area store-and-forward networks,... more We examine two approaches to adaptive routing protocols for wide-area store-and-forward networks, namely, distance-vector and link-state. Distance-vector algorithms have less storage requirements than link-state algorithms. The ARPANET started with a distance-vector algorithm (Distributed Bellman-Ford), but because of long-lived loops, changed to a link-state algorithm (SPF). We evaluate, using a recently developed network simulator, MaRS, the transient and steady-state performance of SPF and two newly proposed distance-vector algorithms (ExBF and MS). Overall, SPF and ExBF have comparable performance and MS is worse.
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Papers by Klaudia Dussa-Zieger