Examinando por Autor "Trefftz, H"
Mostrando 1 - 2 de 2
Resultados por página
Opciones de ordenación
Ítem Combinatory multicast for differentiated data transmission in distributed virtual environments(ACTA PRESS, 2004-01-01) Quiroz, A; Trefftz, H; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesThe shortage of multicast addresses is a factor that limits their use in Intemet-based applications. Since multicast plays a very important role in supporting resource heterogeneity among users of applications with a high demand of computational resources, such as Distributed Virtual Environments, the sparing use of these addresses is of great importance. This paper suggests a scheme for the combination of multicast groups for differentiated data transmission, based on layered multicast, with which the number of different levels of service that can be provided to users of a shared virtual environment with a fixed number of groups is multiplied. For applications where the levels of service correspond to different transmission rates, the scheme also significantly reduces bandwidth utilization. We present a basic method for its implementation and describe preliminary tests to prove its functionality.Ítem Handling heterogeneity in networked virtual environments(MIT PRESS, 2003-02-01) Trefftz, H; Marsic, I; Zyda, M; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesThe availability of inexpensive and powerful graphics cards as well as fast Internet connections make networked virtual environments viable for millions of users and many new applications. It is therefore necessary to cope with the growing heterogeneity that arises from differences in computing power, network speed, and users' preferences. This paper describes an architecture that accommodates the heterogeneity while allowing a manager to define systemwide policies. One of the main objectives of our scheme is to allow slower nodes to participate in the session by preventing fast nodes from flooding slow nodes with too many messages. Policies and users' preferences can be expressed as simple linear equations forming a model that describes the system as a whole as well as its individual components. When solutions to this model are mapped back to the problem domain, viable solutions that accommodate heterogeneity and system policies are obtained. For example, slower nodes may receive less frequent updates than faster ones for one or several information streams. The results of our experiments with a proof-of-concept system are described.