Franz-Josef Rammig

GenERTiCA: A Tool for Code Generation and Aspects Weaving

Model-driven design (MDD) can be perceived in the recent literature as an option to deal with the increasing complexity of the design of distributed embedded real-time systems (DERTS). This paper reports some results of a research project aiming to support a MDD approach, which applies concepts of the aspect-oriented (AO) paradigm in order to improve the treatment of non-functional requirements (NFR) in the design of DERTS. A tool named GenERTiCA, which generates source code from UML diagrams and also weaves aspect adaptations, has been developed to support such MDD/AO approach. This paper presents results regarding the use of GenERTiCA to generate code and implement aspects (from a high-level framework of aspect) for the RT-FemtoJava platform, a RTSJ-based and optimized Java platform for DERTS.

Model-based Runtime Verification Framework for Self-optimizing Systems

This paper describes a novel on-line model checking approach offered as service of a real-time operating system (RTOS). The verification system is intended especially for self-optimizing component-based real-time systems where self-optimization is performed by dynamically exchanging components. The verification is performed at the level of (RT-UML) models. The properties to be checked are expressed by RT-OCL terms where the underlying temporal logic is restricted to either time-annotated ACTL or LTL formulae. The on-line model checking runs interleaved with the execution of the component to be checked in a pipelined manner. The technique applied is based on on-the-fly model checking. More specifically for ACTL formulae this means on-the-fly solution of the NHORNSAT problem while in the case of LTL the emptiness checking method is applied.

(Re-) configurable real-time operating systems and their applications

There are trends in the area of real-time computing to shift from RTOS kernels (fixed or configurable ones) to more flexible approaches, where a RTOS (real-time operating system) is generated exactly in the way it is needed for a specific application context. One example for this approach is the component library Dreams, developed at HNI of Universitat Paderborn. This library offers a fine granular set of components that can be customized at source code level and configured in a very flexible way. The needed configurator, also developed at HNI, is called TEReCS. It allows mapping specific application needs exactly onto the needed and properly customized stet of Dreams component. The available hardware resources are taken into consideration as well. In this paper, we describe how this potential has been used or can be used for rather different classes of applications. The three application examples considered origin from the control of flexible manufacturing systems, synthesis of distributed embedded software, and the real-time image processing needed to offer virtual camera positions in broadcasting sports events. In the first application example, it is discussed how the control of flexible manufacturing systems (so-called holonic approach) can be interpreted as a special kind of a ROTS and which configuration needs have to be considered. In the second example, a model of distributed embedded systems by means of hierarchical predicate/transition nets (a special kind of higher order Petri nets) is directly transformed into a specially configured RTOS. Finally, in the third example, a very special application is considered. From a fixed camera position at known locations, the image that would be produced by a camera position at an arbitrary location (virtual camera) is calculated. This application is intended for sports events like soccer matches. As this, obviously, has to happen in real-time, sophisticated support by a properly tailored RTOS running on processor clusters has to be provided. For this application we decided to configure RTAI Linux in a proper way.

Probabilistic analysis of long-term swarm performance under spatial interferences

Swarm robotics is a branch of collective robotics that outperforms many other systems due to its large number of robots. It allows for performing several tasks that are beyond the capability of a single or multi robot systems. Its global behaviour emerges from the local rules implemented on the level of its individual robots. Thus, estimating the obtained performance in a self-organized manner represents one of the main challenges, especially under complex dynamics like spatial interferences. In this paper, we exploit the central limit theorem (CLT) to analyse and estimate the swarm performance over long-term deadlines and under potential spatial interferences. The developed model is tested on the well-known foraging task, however, it can be generalized to be applied on any constrictive robotic task.

Model-based Runtime Verification Framework

Model-based runtime verification is an extension to the state-of-the-art runtime verification, aimed at checking at runtime the system implementation against the system model (consistency checking) and the system model against the system specification (safety checking). Notice that our runtime verification works at the model level, thus, we do not need to strictly synchronize this runtime verification with the system execution. In fact, we mainly use the runtime information (current states) obtained from the system execution to reduce the state space (of the system model) to be explored. It means that this model-based runtime verification might run before or after the system execution, i.e., switch alternately between a preventive pre-checking mode and a maintaining post-checking mode. In order to make it run ahead of the system execution for as long time as possible, we present two possible strategies so that this runtime verification can selectively reduce the state space (of the system model) to be explored by making the system model enriched with probabilities and additional information derived and learned at the system testing phase.

Analysis of long-term swarm performance based on short-term experiments

Swarm robotics is a branch of collective robotics systems that offers a set of remarkable advantages over other systems. The global behavior of swarm systems emerges from the local rules implemented at the individual level. Therefore, characterizing a global performance obtained at the swarm level is one of the main challenges, especially under complex dynamics such as spatial interferences. In this paper, we exploit the central limit theorem to analyze and characterize the swarm performance over long-term deadlines. The developed model is verified on two tasks: a foraging task and an object filtering task.

Engineering self-coordinating software intensive systems

Wilhelm Schafer, Mauro Birattari, Johannes Blomer, Marco Dorigo, Gregor Engels, Rehan O’Grady, Marco Platzner, Franz Rammig, Wolfgang Reif, and Ansgar Trachtler wilhelm@upb.de 1 Heinz Nixdorf Institute University of Paderborn Furstenallee 11, Pohlweg 98, and Warburger Str. 100 Paderborn, Germany 2 Department of Computer Science University of Paderborn Warburger Str. 100 Paderborn, Germany 3 Department of Control Engineering and Mechatronics University of Paderborn Pohlweg 98 Paderborn, Germany

Engineering Self-Coordinating Real-Time Systems

In this paper we present our vision of establishing self-coordination as the dominant paradigm of operation of future embedded computing environments. This vision is looked at from three different points of view. First of all techniques to model self-coordinating distributed systems in an adequate manner and algorithmic techniques for such systems are discussed. Then the principle of self-coordination is applied to build proper system structures. In a next step such objects are enabled to communicate. Again the potential of self-coordination, now applied to the communication infrastructures is studied. Some proper examples are used to illustrate the approaches and the potentials of self-coordination

Efficient integration of online model checking into a small-footprint real-time operating system

In this paper we discuss how an efficient online model checker and a small-footprint RTOS can be integrated. Alternative approaches are discussed, leading to the decision for a federated approach. An implemented prototype is described and some analytical as well as experimental evaluations are presented.

Efficient Integration of Online Model Checking into a Small-Footprint Real-Time Operating System

In this paper we discuss how an efficient online model checker and a small-footprint RTOS can be integrated. Alternative approaches are discussed, leading to the decision for a federated approach. An implemented prototype is described and some analytical as well as experimental evaluations are presented.