Über die Mechanisierung der Validierung von reaktiven und mobilen Systemen mit unendlichen und parametrisierten Zustandsräumen

The growing influence of telecommunication-systems in all areas has brought with it the need for elaborate and reliable software running on concurrent and, in particular, dynamically changing systems. With the development of such systems becoming ever more complex, the outline and development of mechanized and mechanizable verification-techniques is indispensable. This overall goal can be divided into three tasks: (1) outline of a framework in which (2) complex systems can be analysed, and the (3) design and implementation of efficient proof-techniques. It is certainly beyond the scope of a thesis to provide an integrated framework dealing with these questions within one environment. This work therefore concentrates on dominant aspects of each of the three tasks in separate discussions. A major result of the thesis is that the approaches outlined for each of the three questions obviously fit together, so that they can be used as a basis for the development of an integrated framework. Often automatic verification of larger hardware- and software-applications is impossible, because the systems are too large or even infinite. This thesis focusses on infinite-state and parameterized systems, and builds tool-support on interactive theorem-proving. Further, it concentrates on the validation of correct implementations by exploiting behavioural reasoning. It demonstrates how to apply various techniques to tackle proofs about infinite-state and parameterized systems with large descriptions, discusses the support that theorem-provers can offer, and presents a foundational platform for reasoning about mobile systems in a general-purpose theorem-prover. Several design-decisions have to be taken. This thesis uses process-algebra as a framework, in particular CCS for the description and analysis of infinite-state reactive systems, and the pi-calculus for the discussion of mobile and higher-order systems. For a validation, it applies observation-equivalence, exploiting a range of proof-techniques that have been developed for the two calculi. For all mechanizations, the general-purpose theorem-prover Isabelle/HOL is used.Mit dem zunehmenden Einfluß von Telekommunikationssystemen in allen Bereichen steigt auch der Bedarf an zuverlässiger Software für verteilte und insbesondere dynamisch veränderliche Systeme. Da die Entwicklung derartiger Systeme immer komplexer wird, ist die Konzipierung und Bereitstellung mechanisierter und mechanisierbarer Verifikationstechniken unabdingbar. Dieses globale Ziel läßt sich in drei Aufgaben zerlegen: (1) die Konzipierung einer Umgebung, in der (2) komplexe Systeme analysiert werden können, sowie (3) Design und Implementierung effizienter Beweistechniken. Eine einzelne Dissertation kann natürlich keine integrierte Umgebung bezüglich dieser drei Fragestellungen bereitstellen. Die vorliegende Arbeit konzentriert sich daher in separaten Diskussionen auf herausragende Aspekte jeder einzelner der obengenannten Aufgaben. Ein wichtiges Resultat der Dissertation ist, daß die dabei entwickelten Techniken offensichtlich harmonieren und somit als Grundlage für eine integrierte Umgebung dienen können. Eine automatische Verifizierung größerer Hardware- und Softwareanwendungen ist oft wegen zu großer oder sogar unendlicher Zustandsräume unmöglich. Die vorliegende Arbeit konzentriert sich daher in separaten Diskussionen auf herausragende Aspekte jeder einzelner der obengenannten Aufgaben. Ein wichtiges Resultat der Dissertation ist, daß die dabei entwickelten Techniken offensichtlich harmonieren und somit als Grundlage für eine integrierte Umgebung dienen können. Eine automatische Verifizierung größerer Hardware- und Softwareanwendungen ist oft wegen zu großer oder sogar unendlicher Zustandsräume unmöglich. Die vorliegende Arbeit konzentriert sich auf unendliche und parametrisierte Systeme und verwendet interaktives Theorembeweisen. Dabei geht es vordringlich um die Validierung korrekter Systeme auf der Basis einer operationellen Argumentationsweise. Es wird gezeigt, wie sich verschiedene Beweistechniken auf unendliche und parametrisierte Systeme anwenden lassen, und welche Unterstützung dabei Theorembeweiser bieten können. Darüber hinaus wird eine grundlegende Beweiserplattform für mobile Systeme geschaffen. Verschiedene Designentscheidungen mußten getroffen werden. Die Arbeit basiert auf der Verwendung von Prozeßalgebren, insbesondere CCS für die Beschreibung und Analyse unendlicher reaktiver Systeme, sowie dem Pi-Kalkül für die Diskussion mobiler Systeme und solcher höherer Ordnung. Zur Validierung wird Beobachtungsäquivalenz verwendet, wobei eine Reihe von Beweistechniken Verwendung findet. Alle Mechanisierungen verwenden den Theorembeweiser Isabelle/HOL

Integration of Car-2-Car Communication as a Virtual Sensor in Automotive Sensor Fusion for Advanced Driver Assistance Systems

Advanced driver assistance systems (ADAS) require a comprehensive and accurate situation model. Often in-vehicle sensors do not provide sufficient quality and quantity of information to fulfill the demanding requirements. Car-2-Car communication can be seen as an adaptive sensor that provides additional information regularly but also on demand. Due to the fact that Car-2-Car communication strongly depends on the penetration rate, we argue for a seamless integration of Car-2-Car communication as an additional sensor in automotive sensor fusion. With increasing penetration rate the sensor fusion will significantly benefit and eventually unfold its full potential. Due to the fundamentally different measuring principles of in-vehicle sensors and information provided by Car-2-Car communication, redundancy and complementarity can be leveraged to a great extent, thus, increasing accuracy, reliability and robustness of the situation assessment. In addition to a detailed description of the fusion algorithm this paper outlines DLR’s system architecture for ADAS and an enhanced ACC as an application example to show the potential of our approach

Cooperative Situation Awareness in Transportation

Intelligent Transportation Systems (ITS) became a fast moving eld of research in the last decades, in particular in the context of continuously growing mobility and a high employment of resources starting from energy and material consumption to travel time and nally the human life. As it has already been experienced in other application areas, the introduction of communications technology is able to bring a revolutionary change in structures and behaviors long-believed to be carved in stone. The main idea behind this thesis is the usage of information not as a mere placeholder, e.g. a eld in a static message, but actively utilizing its content and dependencies. This requires an estimation of the actual worth of a single piece of information for the entity itself and the entities which are in communication range. This worth has to be the essential driver for the cooperative situation estimation. The active utilization of information and its cooperative dissemination provides the entities the opportunity to become situation aware and detect hazardous or inefficient situations early in advance. Since information always has a degree of uncertainty which is inherent to information in the real-world problem domain, as we are confronted with in ITS, probabilistic methods will be applied to model situation-relevant information. Conditional probability distributions in state transition models make for the evolvement of the situational information with the progress of time and handle causal dependencies between situational information. Together with a utility-based decision-making process dynamic probabilistic causal decision networks provide the functionality to select optimal actions given sequences of inaccurate and incomplete evidences. This thesis provides concepts and strategies that push forward the exploitation of information in a cooperative way within a probabilistic framework that allows to make various kinds of decisions with maximum utility. For the evaluation of the proposed concepts, the exemplary application Cooperative Adaptive Cruise Control (CACC) has been implemented on the basis of a particle lter which is used for the situation estimation. Initial simulations provided promising results and hence constitute a solid basis for future work in the eld of Cooperative Situation Awareness in Transportation

Novartis School Lab: Bringing Young People Closer to the World of Research and Discovering the Excitement of Science

The Novartis School Lab (http://www.novartis.ch/schullabor) is an institution with an old tradition. The School Lab reaches about 5000 students through internal courses and an additional 5000 children at public science events where they can enjoy hands-on science in disciplines of biomedical research. The subjects range from chemistry, physics, molecular biology and genetics to toxicology and medical topics. The Novartis School Lab offers a variety of activities for youngsters aged 10-20 ranging from lab courses for school classes, continuing education for teachers and development of teaching kits, support for individual research projects to outreach for public science events. Innovation and adaptation to changes of current needs are essential aspects for the Novartis School Lab. Ongoing activities to shape the Novartis Biomedical Learning Lab include design of new teaching experiments, exploration into additional disciplines of biomedical science and the creation of a fascinating School Lab of the future

Investigating the Efficiency of ITS Cooperative Systems for a Better Use of Urban Transport Infrastructures: The iTETRIS Simulation Platform

The use of cooperative ITS communication systems, supporting driving through the dynamic exchange of Vehicle-to- Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages, is a potential candidate to improve the economical and societal welfare. The application of such systems for novel cooperative traffic management strategies can introduce a lot of beneficial effects not only for road safety, but also for the economy related to transportation systems and the environmental impact. Despite this apparent set of promising features, City Road Authorities, which hold a key-role in determining the final adoption of such systems, still look at cooperative systems without sharing a clear opinion. This is mainly due to the current lack of definitive and solid evidences of the effectiveness of such systems when applied in the real world. In order to fill this gap and let Road Authorities estimate the usefulness of such technologies in achieving the objectives dictated by cities’ traffic management policies, the EU consortium iTETRIS is developing a simulation platform for large scale testing of traffic management solutions making use of cooperative ITS systems. Thanks to its own distinguishing features, iTETRIS aims at becoming a good supporting tool for Road Authorities to implement preliminary tests on the effectiveness of ITS solutions prior to investing money for the physical deployment of the communication infrastructures allowing their functioning

Formalising the pi-calculus using nominal logic

We formalise the pi-calculus using the nominal datatype package, based on ideas from the nominal logic by Pitts et al., and demonstrate an implementation in Isabelle/HOL. The purpose is to derive powerful induction rules for the semantics in order to conduct machine checkable proofs, closely following the intuitive arguments found in manual proofs. In this way we have covered many of the standard theorems of bisimulation equivalence and congruence, both late and early, and both strong and weak in a uniform manner. We thus provide one of the most extensive formalisations of a process calculus ever done inside a theorem prover. A significant gain in our formulation is that agents are identified up to alpha-equivalence, thereby greatly reducing the arguments about bound names. This is a normal strategy for manual proofs about the pi-calculus, but that kind of hand waving has previously been difficult to incorporate smoothly in an interactive theorem prover. We show how the nominal logic formalism and its support in Isabelle accomplishes this and thus significantly reduces the tedium of conducting completely formal proofs. This improves on previous work using weak higher order abstract syntax since we do not need extra assumptions to filter out exotic terms and can keep all arguments within a familiar first-order logic.Comment: 36 pages, 3 figure

Competence oriented study in engineering education: examples from the practicing programme

The interdisciplinary and agile processing of projects in teams increasingly characterizes the engineer’s work. Problem-solving skills, creativity, entrepreneurship, and initiative, as well as the ability to engage in dialog and conflict resolution, are relevant competencies for this. All engineering students at TU Ilmenau can work on complex interdisciplinary projects in teams (practicING projects) right from the start of their studies. Participants in these practicING projects can also experience significant steps, aspects, and system engineering methods for demand-oriented products. The paper describes the motivation, the learning goals and methodology of practicING projects from the perspective of the supervising teachers and the participating students. Two examples illustrate the potential of the practicING concept: the projects "Wind turbine model with digital twin" and "CrossLab/ experimental ball drop test environment". Experiences in implementing the practicING projects to date are presented, as well as limitations and possibilities for further development

Performance Evaluation of Policy-Based SQL Query Classification for Data-Privacy Compliance

Data science must respect privacy in many situations. We have built a query repository with automatic SQL query classification according to data-privacy directives. It can intercept queries that violate the directives, since a JDBC proxy driver inserted between the end-users’ SQL tooling and the target data consults the repository for the compliance of each query. Still, this slows down query processing. This paper presents two optimizations implemented to increase classification performance and describes a measurement environment that allows quantifying the induced performance overhead. We present measurement results and show that our optimized implementation significantly reduces classification latency. The query metadata (QM) is stored in both relational and graph-based databases. Whereas query classification can be done in a few ms on average using relational QM, a graph-based classification is orders of magnitude more expensive at 137 ms on average. However, the graphs contain more precise information, and thus in some cases the final decision requires to check them, too. Our optimizations considerably reduce the number of graph-based classifications and, thus, decrease the latency to 0.35 ms in 87% of the classification cases