We introduce a novel approach for real-time decision making with limited memory bounds based on an adaption of the well-known RETE algorithm together with static priorities for conflict resolution. This guarantees fixed execution times independent from the number of rules and facts. Experiments on an unmanned aerial system confirm the adequacy in applications with real-time requirements. The proposed decision system is especially interesting to be used in time-triggered embedded software architectures and for establishing a technical base for building certifiable autonomous unmanned systems.

The implementation of autonomous behaviour in unmanned systems is one of most challenging tasks today. Although the underlying algorithms for decision-making are well known, do no implementations exist for certifiable time-triggered embedded realtime operating systems as used by all modern aerospace and automotive products today. In this publication we present the new approach of realtime decision-making. It allows the a-priori calculation of time and space bounds as a prerequisite for the integration of decision-making in time-triggered embedded software systems.

Faced with the growing complexity of application scenarios for autonomous robots, context-awareness and adaptivity are becoming more and more essential abilities to determine environmental circumstances and to adapt to them accordingly. While semantic technologies are widely used for the modelling of a robot's context, purposive robot behaviour is typically described using plan or plan execution languages which lack explicit semantics for context representations. Context-sensitive adaptive behaviour emerges from the whole transformation process though, from context-awareness to the subsequent execution of associated plans. This comprehensive view of adaptivity lacks sufficient treatment in the field of robotics. Addressing this issue, we have augmented the expressive plan execution language PLEXIL, allowing complex context expressions as Description Logic queries to form an integral part of constructs that define sophisticated behavioural reactions. To demonstrate the symbiosis of context-awareness and plan execution, the enhanced language PLEXIL-DL is employed in the avionics system for a reconnaissance mission of an Unmanned Air Vehicle.

Faced with the growing complexity of application scenarios social robots are involved with, the perception of environmental circumstances and the sentient reactions are becoming more and more important abilities. Rather than regarding both abilities in isolation, the entire transformation process, from context-awareness to purposive behaviour, forms a robot’s adaptivity. While attaining context-awareness has received much attention in literature so far, translating it into appropriate actions still lacks a comprehensive approach. In this paper, we present PLEXIL-DL, an expressive language allowing complex context expressions as an integral part of constructs that define sophisticated behavioural reactions. Our approach extends NASA’s PLEXIL language by Description Logic queries, both in syntax and formal semantics. A prototypical implementation of a PLEXIL-DL interpreter shows the basic mechanisms facilitating the robot’s adaptivity through context-awareness.

Abstract : Sharing information between collaborating military assets by using modern information- and communication technologies is a core principle for complex distributed military operations. In this paper we introduce an Information Management System which combines OWLOntologies and automated reasoning with Publish/Subscribe-Systems, providing for a shared but decoupled data model. We emphasise the novel application and lack of practical experience of using Semantic Web technologies in areas other than originally intended. That is, aiding decision support and software design in the context of a mission scenario for an unmanned system. Experiments within a complex simulation environment show the immediate bene ts of a semantic informationmanagement and -dissemination platform: Clear separation of concerns in code and data model, increased systems re-usability and extensibility as well as simpli ed integration of external information sources.

Die Erfindung betrifft ein Publikations-Abonnementsystem umfassend einen oder mehrere Herausgeber (6) zur Erzeugung von Nachrichten, einen oder mehrere Abonnenten (5) zur Registrierung eines oder mehrerer Abonnements und zum Empfangen von Nachrichten aufgrund dieser Abonnements, eine oder mehrere Einrichtungen zur Erzeugung von Datenanfragen, eine Verwaltungseinrichtung (4) zur Verwaltung der Anfrage des Abonnenten, eine Uberprufungseinrichtung (2) zur Uberprufung der Nachricht des Herausgebers (6) bzw. der Anfrage des Abonnenten (5) auf Gultigkeit, wobei die Nachricht bzw. die Anfrage bezuglich Syntax uberpruft wird und mogliche Relationen zwischen den Daten in der Nachricht bzw. der Anfrage unter Berucksichtigung vorgegebener Datenmodelle bestimmt werden, eine oder mehrere dynamisch oder statisch instanziierbare Wissensbasen (3), jeweils umfassend eine Datenbank (8) zur Speicherung der Nachrichten und eine Einrichtung (9) zur Schlussfolgerung uber die Inhalte der Datenbank (8) unter Berucksichtigung eines der jeweiligen Wissensbasis (3) zugeordneten Datenmodells (10).

Today’s mission software requires ever more sophistication, being faced with the challenges of conducting Nnetwork-centric Operations (NCO) and exhibiting mission autonomy. Addressing these challenges, together with improving the engineering process in general, is the main output of the project described in this paper, accomplished at EADS Military Air Systems. The project comprises an architectural concept, a methodology, a development environment, a runtime environment and a simulation connector. The adequacy of the approach was demonstrated by means of a prototypical implementation of a NCO scenario.

Using middleware technologies in modern distributed embedded environments, one is often faced with connecting incompatible transport media to the communication stack, especially in the military domain. In case of CORBA, natively unsupported media can be plugged in via ESIOP, integrating it into the middleware. This approach tightly couples media to middleware and tends to be unportable between middleware technologies. In contrast, this paper suggests transport abstraction by providing IPv6 adapters for each medium, exploiting the predominance of IP support in middleware and existing adapters. Apart from the flexibility gained compared to transport integration, the proof-of-concept implementations of both approaches, based on CORBA and CAN, show an up to a tenfold improvement in invocation time over integration. Transport abstraction not only reduces the problem to adapting media to IPv6, but also allows transport media independent substitution of middleware and vice versa.

Network-centricity and autonomy are two buzzwords that have found increasing attention since the beginning of this decade in both, the military and civil domain. Although various conceptions exist of which capabilities are required for a system to be considered network-centric or autonomous, there can hardly be found proposals or prototypes that describe concrete transformations for both capabilities into software. The presented paper reviews work accomplished at EADS Military Air Systems driven by the need to develop an infrastructure that supports the realisation of both concepts in software with respect to traditional and modem software engineering principles, e.g., re-use and service-oriented development. This infrastructure is provided in form of a prototypical framework, accompanied by configuration and monitoring tools. Tests in a complex scenario requiring network-centricity and autonomy have shown that a significant technical readiness level can be reached by using the framework for mission software development.

Future unmanned aerial systems demand capabilities to perform missions automatically to the greatest possible extent. Missions like reconnaissance, surveillance, combat, or SEAD usually consist of recurring phases and contain resembling or identical portions such as autonomous flight control, sensor processing, data transmission, communication or emergency procedures. To avoid implementing many similar singular solutions, a systematic approach for the design of an unmanned avionic software architecture is needed. Current approaches focus on a coarse system design, do not integrate off-the-shelf middleware, and do not consider the needs for having on-board intelligence.

In our work we propose a multi-agent based real-time architecture for the implementation of multi-agent based heterogeneous Integrated Modular Avionics (IMA). It utilizes a distributed blackboard architecture with rule-based event notification in order to efficiently minimize communication overhead and to provide a flexible, scalable, and fault-tolerant peer-topeer infrastructure for information dissemination between agents situated in arbitrary safety partitions. Moreover, the proposed architecture conforms to the widely accepted standards defined by the Foundation for Intelligent Physical Agents (FIPA) – an organization coping with multi-agent technology. 1 General Introduction Consider an unmanned aerial vehicle (UAV) autonomously acting in a network-centric concerted actions scenario. It will be confronted with a vast of sensor data originating from its own sensors and other data sources (like other UAVs, Satellites, Ground Station, etc.). Ideally, its avionic system should process all this data in real-time and initiate appropriate actions. But because of a UAV’s limited energy, intraavionics communication bandwidth, and processing resources, this may not be feasible. A solution for this problem is to enable avionic components to intelligently adapt to the current system needs and situation context in order to control the focus of information processing. An IMA architecture is thus required to provide a huge amount of flexibility. Another requirement that must be considered (regardless of a concrete architecture design) in order to make it a viable approach for IMA is to implement fault-tolerance and to provide support for safety partitions, which guarantee physical bounds with respect to failure propagation in case of malfunction of some subsystem(s). 1.1 The Client-Server Based Approach Currently, there are some efforts to realize IMA using real-time operating system (e.g. LynxOS or VxWorks) and client-server based middleware technologies (e.g. RT/FT-CORBA) that enable transparent communication over the network and fault-tolerant integration of heterogeneous hardware and software components. Those client-server based architecture approaches, however, have some drawbacks with respect to flexibility and fault-tolerance. Additionally, the CORBA standard is very complex which complicates the necessary certification of CORBA orbs, not to mention the resulting high costs. 1.2 The Peer-to-Peer Based Approach In contrast to purely client-server based approaches some new research efforts focus on the realization of systems in a peer-to-peer fashion, because the latter approach promises considerable advantages over the former one regarding fault-tolerance, scalability, and flexibility. However, in a peer-to-peer system new problems arise that have to be dealt with. A

We present the concept of cooperative vision and its application to a multi-agent system with special attention to the integration of vision. Cooperative vision can be described as a type of distributed vision, where several agents working in a shared environment are involved. The object recognition task was distributed to several agents in order to demonstrate the concept of cooperative vision. This enables, on the one hand, a verification of objects by several agents and, on the other hand, a localization of spatial positions of other agents. A Bayesian approach is used for the combination of conclusions of several agents. Experiments done so far show significant results with regard to both tasks.

This paper introduces an approach to recognize objects in a group of observers. The fundamental idea of this approach is based on the usage of cooperation at object level in order to overcome limitations of typical recognition applications which often lead to ambiguous interpretations. By integrating individual hypotheses which were calculated at spatial distributed viewpoints, the robustness of the recognition results can be increased significantly. Experiments confirm the benefit of fusing object hypotheses from multiple observers.

Internal Structure of a Robot. To control a group of cooperating autonomous mobile robots, we use a multi-agent architecture as introduced in [LBLM98]. The structure of a single robot consists of a set of concurrent Elementary Agents situated on different levels of abstraction. The levels are defined by different response time and are structured as reflexive, tactical, and strategical layer. E.g. in the reflexive layer tasks like object recognition and self-localization are processed.

In der vorliegenden Arbeit wird der Begriff der visuellen Kooperation bzw. kooperativen Bildverarbeitung definiert, analysiert und in Bezug gesetzt zum Schichtenmodell der Bildverarbeitung. Wie sich zeigen wird, kann durch die Verteilung der Sichtaufgabe auf mehrere raumlich getrennte Beobachter eines Teams die Zuverlassigkeitsrate bei der Erkennung gesteigert werden. Die Vorteile solch eines verteilten Sehens liegen in der Nutzung von potentiellem Wissen des Teams, in der Analyse von Szenen mit statischen oder dynamischen Objekten sowie in der Generierung robuster Hypothesen. Verteilt berechnete Daten lassen sich jedoch im allgemeinen nur dann kombinieren, wenn sie in Bezug zueinander gesetzt werden konnen. Diese Fahigkeit zur Selbstlokalisierung eines Beobachters, z.B. eines Roboters, bildet damit die Voraussetzung zur visuellen Kooperation. Nach einer kurzen Einfuhrung in die Problemstellung der Selbstlokalisierung schliest dieser Bericht mit Anwendungsbeispielen zu visueller Kooperation aus der high-level Bildverarbeitung vorgestellt.

This paper presents the hardware and software design principles of the medium size RoboCup Team CoPS which are developed by the image understanding group at the Institute for Parallel and Distributed High Performance Systems (IPVR) of the University of Stuttgart. By adapting already successfully tested multiagent software concepts by our group to the domain of robotic soccer we intend to improve those concepts at the field of realtime applications with uncertain sensory data.

This paper explores the problem of object recognition from multiple observers. The basic idea is to overcome the limitations of the recognition module by integrating information from multiple sources. Each observer is capable of performing appearance-based object recognition, and through knowledge of their relative positions and orientations, the observerrs can coordinate their hypotheses to make object recognition more robust. A framework is proposed for appearance-based object recognition using Canny edge maps that are effectively normalized to be translation and scale invariant. Object matching is formulated as a non-parametric statistical similarity computation between two distribution functions, while information integration is performed in a Bayesian belief net framework. Such nets enable both a continuous and a cooperative consideration of recognition result. Experiments which are reported on two observers recognizing mobile robots show a significant improvent of the recognition results.