Gottfried Koppensteiner

Application of an ontology in a transport domain

This paper presents an application of an ontology in combination with multi-agent technologies in a transport domain. The need for flexibility and agility in this domain is continuously growing due to the increasing complexity in the processes where this domain is used. The ontology, we propose, is shared among agents and provides the common agreement and understanding about the used concepts. This approach offers a convenient way for design and control of distributed systems reducing their complexity, increasing flexibility and enhancing fault tolerance.

Decentralized Reconfiguration of a Flexible Transportation System

This paper presents a decentralized approach for the local reconfiguration of control software, which is based on a multiagent system with ontology-driven reasoning. We apply this approach to a transportation system and demonstrate improvements on efficiency, fault tolerance and stability with several experiments. One key element to achieve these results is the use of ontologies to ensure the consistency of local reconfiguration of the control software with the desired global behavior of the system. To show the feasibility of our approach in a realistic industrial setting, we implemented the multiagent system on the “Testbed for Distributed Holonic Control” at the Automation and Control Institute. We also used simulation to analyze its impact on the system performance. The simulation results as well as the real system experiments indicate that our approach is able to cope with the dynamic nature of the transportation domain thereby enhancing reconfigurability, robustness, and fault tolerance.

Integrating software agents and IEC 61499 realtime control for reconfigurable distributed manufacturing systems

The need for agility in manufacturing systems is continuously growing. This is caused by increasing complexity and decreasing life cycles of the produced goods. This paper proposes a modular, reconfigurable manufacturing system, based on a distributed three layer architecture, consisting of mechatronic components, an IEC 61499 based distributed low level control and on top a multi agent system as high level control. Adaptivity to new demands is added by the inclusion of knowledge in the top layer. Agents are able to understand the structure of the manufacturing system and the produced goods. This enables the high level control to reconfigure the underlying system. To gain most value of this combination, agents and the low level control have to work together in an integrated environment. An interface for connecting distributed low level control and the multi agent system is presented.

Application of a communication interface between agents and the low level control

Increasing complexity in the transport domain requires flexible and reconfigurable control architectures. In this paper we present the deployment of an agent-based system in this domain splitting the manufacturing control into two layers: a high level control based on agents and a low level control based on the standard IEC 61499. A further focus is laid on the design of a generic communication interface between the control layers and a graphical representation of the target system that allows the simulation of failure scenarios.

A change-direction-algorithm for distributed multi-agent transport systems

Transport systems of the future have to be flexible and adaptive in order to cope with failures and unexpected disturbances. Agent technology provides a good framework for handling with dynamics in large complex systems, using distributed control of the system increasing flexibility and enhancing fault tolerance. This paper researches how software agents supported with ontologies can improve the efficiency of transport systems. An algorithm for the transport system reconfiguration by changing the direction of conveyors is presented.

Intelligent-agent based approach for assembly automation

The assembly process used by most manufacturers today is based on disconnected ordering, scheduling as well as execution processes, and lacks on agility needed for enterprise-wide integration. This paper presents a knowledge-based multi-agent framework to enhance the agility in assembly systems. Agents with specialized expertise and high level of autonomy cooperate together to accomplish individual, as well as system objectives. In order to increase system flexibility and adaptability negotiation mechanisms for task allocation have been applied. An ontology is used to support ldquounderstandingrdquo between agents during the communication, as well as to define the domain entities and relations between them. This research demonstrates the feasibility of our approach and its efficiency in dynamic situations.

Deployment of an ontology-based agent architecture on a controller

Multi-agent systems have proven to be a powerful technology for improving flexibility and agility in a complex manufacturing environment. In such systems, an ontology is a crucial element for knowledge representation of the external environment or the agents domain of application as well as for ensuring interoperability between agents. The agents decision component uses this world representation to coordinate the global behavior of the agent and delegate specific tasks. The placement of the agents decision part on a controller brings improvements in scalability, reconfigurability as well as less dependency from human intervention. In this paper we describe an important step needed to be done by excluding the unnecessary GUIs and by directly connecting the used software tools in order to place the entire framework on an embedded controller.

Semantische Technologien – Stand der Technik

SummaryThe information and knowledge exchange between partners play a critical role for the success of every company. It is of biggest importance to have an optimized information flow to find the appropriate knowledge source in the desired quality and in adequate time. In current companies it is usually not transparent to the partners, which knowledge is available at which partners site. Semantic offers a possibility to model all relevant concepts important for cooperating organizations in an ontology. An ontology can capture actions and events in a uniform and processable way so that they can be recorded in time and further analyzed. An ontology models the associations and dependencies between the domains. This allows business partners to build open communities that define and share the semantics of the information exchanged in their domain. The development of an ontology for the most companies is still not very common, as many companies hesitate to start this resource-intensive process. This study analyzes the current state of the art in Austrian companies related to the application and capabilities of the semantic technology.ZusammenfassungDer Informations- und Wissensaustausch zwischen Partnern spielt eine kritische Rolle für den Erfolg von Unternehmen. Es ist von größter Bedeutung, einen optimierten Informationsfluss zu haben, d. h. die passende Informationsquelle in der gewünschten Qualität und in der kürzesten Zeit zu finden. Für aktuelle Unternehmen ist es üblicherweise nicht transparent, welches Wissen bei den einzelnen Partnern vorhanden ist. Semantik bietet die Möglichkeit, alle relevanten Konzepte, die für die erfolgreiche Zusammenarbeit der Unternehmen wichtig sind, in einer Ontologie abbilden zu können. Die Ontologie ist in der Lage, exakte Informationen und Aktionen über ein Ereignis in einer einheitlichen Weise darzustellen, so dass sie auch in Echtzeit analysiert und weiterverarbeiten werden können. Die Ontologie modelliert dabei die Verbindungen und Abhängigkeiten der einzelnen Themen. Dies erlaubt den Geschäftspartnern, offene Gemeinschaften zu errichten, welche die Regeln für den Informationsaustausch in ihren Domänen (Semantik) gemeinschaftlich definieren und teilen. Die Entwicklung einer solchen Ontologie ist unter den meisten Unternehmen noch nicht verbreitet, da viele Firmen zögern, einen solchen ressourcenintensiven Prozess zu beginnen. Diese Studie analysiert den derzeitigen Stand der Technik in österreichischen Unternehmen im Bezug auf den Einsatz und die Einsatzmöglichkeiten von semantischer Technologie.

A Decision Support Algorithm for Ontology-Based Negotiation Agents within Virtual Enterprises

This paper describes an application of a distributed knowledge-based multi-agent architecture to support automated negotiation between and within virtual enterprises (VE). Considering constraints of traditional negotiation approaches (predetermined protocols as well as hard-coded and non-adaptive strategies), we combine the agent paradigm with ontology-based solutions to overcome these limitations. Our negotiation ontology, used by agents, acts as a general framework that defines the basic terminology, interaction and protocols enabling agent to understand each other and to reach an agreement. Our multi-agent architecture consists of two types of agents that have rule-based behaviors. One is the Auctioneer that starts, monitors and ends an auction process in the name of a user that offers a particular product/service. Every new user who joins an auction has a configured MarketAgent that takes a participant role bidding for a product/service. To help an agent in its decision, a special decision support algorithm is implemented to recommend the best negotiation strategy, based on the user interests. We also describe the initial implementation of the system using JADE and JESS.

Ontology-based resource allocation in distributed systems using director facilitator agents

Multi-Agent Systems provide a suitable concept to easily map processes, interaction and knowledge into agents. This paper discusses the development of ontology-based multi-agent system and explores some performance of the system. We also present a typical scenario for resource allocation and demonstrate a promising approach for integration of process planning and scheduling functions.