Sequencing of multi‑robot behaviors using reinforcement learning

Given a collection of parameterized multi-robot controllers associated with individual behaviors designed for particular tasks, this paper considers the problem of how to sequence and instantiate the behaviors for the purpose of completing a more complex, overarching mission. In addition, uncertainties about the environment or even the mission specifications may require the robots to learn, in a cooperative manner, how best to sequence the behaviors. In this paper, we approach this problem by using reinforcement learning to approximate the solution to the computationally intractable sequencing problem, combined with an online gradient descent approach to selecting the individual behavior parameters, while the transitions among behaviors are triggered automatically when the behaviors have reached a desired performance level relative to a task performance cost. To illustrate the effectiveness of the proposed method, it is implemented on a team of differential-drive robots for solving two different missions, namely, convoy protection and object manipulation.     

An Interoperable Grid Information System for Integrated Resource Monitoring Based on Virtual Organizations

In many Grid infrastructures different kinds of information services are in use, which utilize different incompatible data structures and interfaces to encode and provide their data. Homogeneous monitoring of these infrastructures with the monitoring data being accessible everywhere independently of the middleware which provided it, is the basis for a consistent status reporting on the Grids’ resources and services. Thus, interoperability or interoperation between the different information services in a heterogeneous Grid infrastructure is required. Monitoring data must contain the identity of the affected Virtual Organization (VO) so that it can be related to the resources and services the VO has allocated to enable VO-specific information provision. This paper describes a distributed architecture for an interoperable information service, which combines data unification and categorization with policies for VO membership, VO resource management and data transformations. This service builds the basis for an integrated and interoperating monitoring of Grids, which provide their data to more than one VO and utilize heterogeneous information services.     

Sequencing of multi-robot behaviors using reinforcement learning

Given a collection of parameterized multi-robot controllers associated with individual behaviors designed for particular tasks,this paper considers the problem ...     

UNICORE 6 — Recent and Future Advancements

UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments.     

Hochtemperaturgasdynamik

Zusammenfassung Es wird eine einführende Darstellung des Gebietes der Hochtemperaturgasströmungen ohne Transporterscheinungen, elektromagnetische Erscheinungen und äußere Kräfte gegeben. Der Unterschied zwischen einer solchen Hochtemperaturgasströmung und der entsprechenden Strömung eines idealen Gases konstanter spezifischer Wärmen rührt von den inneren Prozessen im Medium her. Bilden die inneren Prozesse einen reversiblen Vorgang, fällt die Hochtemperaturgasströmung ebenso wie die entsprechende Strömung eines idealen Gases konstanter spezifischer Wärmen in die Klasse der Strömungen physikalisch homogener Medien. Zwischen den beiden Strömungen besteht dann noch enge physikalische Verwandtschaft, was erhebliche quantitative Unterschiede nicht ausschließt. Bilden die inneren Prozesse dagegen einen irreversiblen Vorgang, treten tiefgreifende Unterschiede gegenüber der entsprechenden Strömung eines idealen Gases konstanter spezifischer Wärmen und der zugehörigen Strömung mit reversiblem inneren Vorgang auf. Der vorliegende Artikel verfolgt mehrere Ziele. Die Einleitung soll ein erstes Verständnis vermitteln über das zu behandelnde Gebiet, über seine Stellung in der Strömungsmechanik und wichtige Anwendungsmöglichkeiten. In den Abschnitten 2 und 3 wird das für die Berechnung von Hochtemperaturgasströmungen praktisch wichtigste thermodynamische Modell des realen Gases kritisch dargestellt. Der Abschnitt 4 bezieht sich auf den Fall reversiblen inneren Vorganges, der Abschnitt 5 auf den Fall irreversiblen inneren Vorganges. Diese beiden Abschnitte sollen an Hand spezieller Strömungsformen die erwähnte enge physikalische Verwandtschaft bzw. die tiefgreifenden Unterschiede aufzeigen.

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High temperature gas dynamics

Summary An introduction to the field of high temperature gas flows without transport phenomena, electromagnetic phenomena and external forces is presented. The difference between such a flow and the corresponding flow of an ideal gas of constant specific heats comes from internal changes in the fluid. If these changes form a reversible process, the high temperature gas flow as well as the corresponding flow of an ideal gas of constant specific heats belong to the general class of flows of a physically homogeneous medium. A close relationship therefore still exists between the two flows in question. However, if the internal changes form an irreversible process, fundamental differences arise in comparison with the corresponding flow of an ideal gas of constant specific heats and the corresponding flow with reversible process, respectively. The introduction of the present article yields a first understanding of the field to be considered and informs about important applications. Section 2 describes the real gas model adopted in this article. In section 3 various concepts of thermodynamic equilibrium are explained. Section 4 and 5 demonstrate the close relationship and the fundamental differences mentioned above by means of suitable flow patterns.

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Mit 13 Abbildungen

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Erweitertes Vorlesungsmanuskript des Verfassers für den 2. Lehrgang für Raumfahrttechnik in Göttingen, 1. bis 5. März 1971.