Jürgen Mottok

Learning and teaching software process models

Software process models are fairly abstract tools for organizing large, complex software development projects. Since particularly undergraduate students commonly do not have any experience in being part of such a project, their understanding of the benefits and shortcomings of particular process models is very limited. Even more, frequently they are not aware of the need to follow a particular process model since their previous one-person software assignments were too small for requiring any such model at all.

Technische Sicherheit und Informationssicherheit

Einführung Unsere Gesellschaft hängt in umfassendem Maße vom zuverlässigen Funktionieren technischer Systeme und vom jederzeit möglichen Zugriff auf authentische und korrekte Informationen ab. Innerhalb dieser technischen Systeme spielen informationsspeichernde bzw. -verarbeitende Systeme eine immer größere Rolle; in einzelnen Branchen tragen sie mittlerweile über 50 % zur Wertschöpfung bei [1]. Diese Systeme, egal wo sie eingesetzt werden (z. B. in Rechenzentren, Banken, Autos usw.) sollen im Folgenden als IT-Systeme (kurz für: informationstechnische Systeme) bezeichnet werden. Durch ihre Funktion können sich technische Systeme in allen Lebensbereichen und auf alle vorstellbaren Werte auswirken, die sämtliche für Nutzer bedeutsame Aspekte umfassen, etwa menschliches Leben, Gesundheit und Unversehrtheit, Vermögen, Wissen, Gegenstände und persönliche Daten beteiligter ebenso wie nur mittelbar beteiligter Personen. Im Allgemeinen muss man davon ausgehen, dass technische Systeme nicht immer fehlerlos sind und arbeiten, sondern dass sie von Beginn an bestehende oder erst mit der Zeit auftretende Schwachstellen enthalten. Schwachstellen können selbst bei bestimmungsgemäßem Gebrauch eines technischen Systems zu Fehlfunktionen führen, durch die Personen, Umwelt, Infrastruktur oder Daten geschädigt werden. Erst recht kann die funktional falsch verstandene oder grundsätzlich unsachgemäße Benutzung technischer, auch korrekt funktionierender Systeme die oben genannten Werte beeinträchtigen. Die vielfältigen Probleme und Aspekte bezüglich der Sicherung von IT-Systemen gegen derartige Effekte gewinnen zunehmend an Bedeutung. Im Arbeitskreis ,,Begriffsbildung“ des GIFachbereichs ,,Sicherheit“ ist in den letzten Jahren in intensiven Diskussionen versucht worden, Grundbegriffe zur Charakterisierung dieses Problembereichs, die in der Fachöffentlichkeit mit

The Regensburg Concept of P-Seminars — How to organize the interface between secondary school and university education to create a didactic cooperation between teaching and learning of Software Engineering with Lego Mindstorms NXT Embedded Robot Systems

This paper describes the background and the theory of the learning arrangement “The Regensburg Concept of P1 - Seminars” and its potential fields of application. This conception was designed to meet the various requirements caused by the Bologna Accords and the restructuring of the senior years of German secondary school education. At the same time it aims at finding solutions for a severe problem topical in Germany: the lack of students qualifying in MINT (the fields of mathematics, informatics, natural sciences and techniques.)

Developing visual expertise in software engineering: An eye tracking study

Program comprehension and the ability to find program errors are key skills of software engineering. The aim of this pilot study was to examine the visual processes of novice and advanced programmers in authentic tasks. Fifteen novices and eight advanced programmers were given eight short pieces of code. Their task was to either identify an error or give the output of the code. Eye movements and keyboard activity were recorded. On average, the novices spent more time reading the code than composing the response, whereas the more advanced programmers started composing the response sooner and spent more time on it. In general, the advanced programmers had shorter fixations and saccades. The results suggest that the advanced programmers are quicker to grasp the essence of the code and able to see more details in it. The advanced programmers had shorter fixations and saccade lengths during the second phase which might indicate the process of chunking.

Optimization of real-time multicore systems reached by a Genetic Algorithm approach for runnable sequencing

The deployment of complex real-time systems with everyday increasing demands and possibilities, is a challenging task for engineers when performance and efficiency have to be maximized while cost have to be minimized at the same time. For already designed systems it became necessary to perform different modifications in order to find optimal software architecture configuration by respecting all timing constraints which are essential when speaking of real-time systems. In this work, we present a model-based approach of optimizing the execution sequence of runnables within tasks in order to reduce the systems reaction times by improving the overall signal flow duration. Hereby, a genetic optimization algorithm is used to create and evaluate multiple solutions for the runnable sequencing problem. We conclude by demonstration the efficiency of the presented approach with experimental results.

Just-in-Time Teaching in software engineering: A Chinese-German empirical case study

Learning centered teaching becomes an important factor in a global perspective of learning software engineering. The Just-in-Time Teaching approach is used in a Chinese-German empirical case study. In a one year terminated project we will analyze the performance of our students in an active learning scenario with Just-in-Time Teaching and Peer Instruction. We will contribute an inter-cultural comparison of achieved competencies by students self-assessment and teachers observation.

Required competences in software engineering: Pair programming as an instrument for facilitating life-long learning

The professional requirements in software engineering have become highly volatile due to the complexities of project development and rapid and innovative changes occurring in the field. Therefore, the development of inter-personal and social competences has gained central importance in the training of software developers. The following text will present a concept allowing to acquire competences by using Pair Programming as an instrument. Moreover, arrangements for learning and teaching will be presented facilitating the acquisition of these competences. By approaching the issue of competence acquisition on a technical as well as on an educational and social level, lifelong learning is facilitated and supported.

Probabilistic worst case response time estimation for multi-core real-time systems

Traditional methods rely on Static Timing Analysis techniques to compute the Worst Case Response Time for tasks in real-time systems. Multi-Core real-time systems are faced up with concurrent task executions, semaphore accesses, and task migrations where it may be difficult to obtain the worst case upper bound. A new three staged probabilistic estimation concept is presented. Worst Case Response Times are estimated for tasksets which consist of tasks with multiple time bases. The concept involves data generation with sample classification and sample size equalization, model fit and Worst Case Response Time estimation on the basis of extreme value distribution models. A Generalized Pareto Distribution model fit method which includes threshold detection and parameter estimation is also presented. Sample classification in combination with the new Generalized Pareto Distribution model fit method allows to estimate Worst Case Response Times with low pessimism ranges compared to estimation methods that uses the Generalized Pareto or the Gumbel max distribution without sample classification.

Just-in-Time-Teaching experience in a Software Design Pattern course

Teaching design patterns in computer science introductory sequence is more difficult than learning it. We present a Just-in-Time-Teaching (JiTT) practice in Software Design Patterns course targeted to entry level students. We proposed a model that combines JiTT concepts with didactic considerations, preparation materials, in-class sessions and post-lecture assignments. We have effectively used this approach to teach two undergraduate classes. The paper also presents the results of a survey conducted to identify the effectiveness of the JiTT activities through warm-up questions, class-wide discussions, experiments and exercises.

Towards the Derivation of Guidelines for the Deployment of Real-Time Tasks on a Multicore Processor

The deployment of automotive software on a multicore processor includes the task of mapping executables to cores. Given the number of possible solutions, integrators have to solve a complex problem. Considering multiple, often conflicting goals like minimizing task response times and memory consumption, complexity further increased with the advent of multicore processors. We present a model-based approach for deriving design rules supporting integrators with statically mapping tasks to a multicore ECU. First, an evolutionary algorithm is used to sample the design space. For each sample, a model-based analysis is performed, resulting in the required fitness values according to the system metric objectives. Finally, subsets of the sample population are used to derive deployment guidelines by evaluating similarities between highly ranked solutions. This reduces the number of solutions to be considered by the integrators by orders of magnitude. In a case-study, we demonstrate the developed approach on an artificial automotive engine management system.