Jens B. Schmitt

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Layer encoded video is an elegant way to allow adaptive transmissions in the face of varying network conditions as well as it supports heterogeneity in networks and clients. As a drawback quality degradation can occur, caused by variations in the amount of transmitted layers. Recent work on reducing these variations makes assumptions about the perceived(More)
In this paper we describe the design, implementation, and analytical background of the DISCO Network Calculator. The DISCO Network Calculator is an open-source toolbox written in Java™ which we developed for worst-case analyses based on network calculus. To our knowledge it is the first of its kind. It allows to do network analyses regarding(More)
Node deployment is a fundamental issue to be solved in Wireless Sensor Networks (WSNs). A proper node deployment scheme can reduce the complexity of problems in WSNs as, for example, routing, data fusion, communication, etc. Furthermore, it can extend the lifetime of WSNs by minimizing energy consumption. In this paper, we investigate random and(More)
Network calculus has proven as a valuable and versatile methodology for worst-case analysis of communication networks. One issue in which it is still lacking is the treatment of aggregate multiplexing, in particular if the FIFO property cannot be assumed when flows are merged. In this paper, we address the problem of bounding the delay of individual traffic(More)
Network calculus is a min-plus system theory which facilitates the efficient derivation of performance bounds for networks of queues. It has successfully been applied to provide end-to-end quality of service guarantees for integrated and differentiated services networks. Yet, a true end-to-end analysis including the various components of end systems as well(More)
Simulations are an important tool in network research. As the selected topology often influences the outcome of the simulation, realistic topologies are needed to produce realistic simulation results. We first discuss the different types of topologies and present our collection of real-world topologies that can be used for simulation. We then define several(More)
In this paper, we take an availability-centric view on Quality of Service (QoS) and focus on the issues of providing availability guarantees for widely distributed systems such as web servers and peer-to-peer (P2P) file sharing systems. We propose a concept called Quality of Availability (QoA) in which the availability is treated as a new controllable QoS(More)
Today’s wireless sensor networks (WSN) focus on energy-efficiency as the main metric to optimize. However, an increasing number of scenarios where sensor networks are considered for time-critical purposes in application scenarios like intrusion detection, industrial monitoring, or health care systems demands for an explicit support of performance guarantees(More)