University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Control reconfiguration & Software. The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

A peer-to-peer architecture for massive multiplayer online games

Abstract: Massive Multiplayer Online Games with their virtual gaming worlds grow in user numbers as well as in the size of the virtual worlds. With this growth comes a significant increase of the requirements for server hardware. Today an MMOG provider usually faces the problem of serving thousands of users with entire server clusters. Peer-to-Peer networks with their high scalability and flexibility meet the requirements of connecting hundreds of thousands of people all over the world without a central server. In doing so the network bandwidth requirements remain at a reasonable level.In this work we propose to combine MMOGs with a Peer-to-Peer network. We introduce a game architecture capable of exploiting the flexibility and scalability of P2P networks. A P2P architecture based on an overlay network using distributed hash tables with support for persistent object storage and event distribution has been developed to meet MMOG requirements.

Smooth Fréchet globalizations of Harish-Chandra modules

Abstract: We give an alternative proof of the Casselman-Wallach globalization theorem. The approach is based on lower bounds for matrix coefficients on a reductive group.

A Time-Space Network Approach for the Integrated Vehicle-and Crew-Scheduling Problem with Multiple Depots

Abstract: This paper discusses the integrated vehicle-and crew-scheduling problem in public transit with multiple depots. It is well known that the integration of both planning steps discloses additional flexibility that can lead to gains in efficiency, compared to sequential planning. We present a new modeling approach that is based on a time-space network representation of the underlying vehicle-scheduling problem. The integrated problem is solved with column generation in combination with Lagrangian relaxation. The column generation subproblem is modeled as a resource-constrained shortest-path problem based on a novel time-space network formulation. Feasible solutions are generated by a heuristic branch-and-price method that involves fixing service trips to depots. Numerical results show that our approach outperforms other methods from the literature for well-known test problems.

Automatic conformance testing of web services

Abstract: Web Services are the basic building blocks of next generation Internet applications, based on dynamic service discovery and composition. Dedicated discovery services will store both syntactic and behavioral descriptions of available services and guarantee their compatibility with the requirements expressed by clients. In practice, however, interactions may still fail because the Web Service's implementation may be faulty. In fact, the client has no guarantee on the quality of the implementation associated to any service description. In this paper, we propose the idea of high-quality service discovery incorporating automatic testing for validating Web Services before allowing their registration. First, the discovery service automatically generates conformance test cases from the provided service description, then runs the test cases on the target Web Service, and only if the test is successfully passed, the service is registered. In this way, clients bind with Web Services providing a compatible signature, a suitable behavior, and a high-quality implementation.

On the isomorphism classes of weighted spaces of harmonic and holomorphic functions

Abstract: Let Ω be either the complex plane or the open unit disc. We completely determine the isomorphism classes of Hv = { f : Ω → C holomorphic : sup z∈Ω |f(z)|v(z) < ∞ } and investigate some isomorphism classes of hv = { f : Ω → C harmonic : sup z∈Ω |f(z)|v(z) < ∞ } where v is a given radial weight function. Our main results show that, without any further condition on v, there are only two possibilities for Hv, namely either Hv ∼ l∞ or Hv ∼ H∞, and at least two possibilities for hv, again hv ∼ l∞ and hv ∼ H∞. We also discuss many new examples of weights.