Ulrich Fiedler

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The Internet and the proliferation of inexpensive computing power in the form of clusters of workstations or PCs provide the basic hardware infrastructure for business to business electronic commerce in small and medium enterprises. Unfortunately, the corresponding software infrastructure is still missing. In this paper we show a way to develop appropriate(More)
Electronic commerce has attracted a great deal of attention recently. Among the different types of electronic commerce, business-to-business is the one most widespread in terms of turnover. An important aspect in business to business e-commerce scenarios is how to meet response time and throughput requirements of applications in spite of execution taking(More)
One of the key invariants in computer and communication systems is that im¬ portant characteristics follow long-or heavy-tailed distributions. This means that the tail of these distributions declines according to a power law. Hence, the probability for extremely large values is non-negligible. For example, such distributions have been found to describe the(More)
Simulations with web traffic usually generate input by sampling a heavy-tailed object size distribution. As a consequence these simulations remain in transient state over all periods of time, i.e. all statistics that depend on moments of this distribution, such as the average object size or the average user-perceived latency of downloads, do not converge(More)
Deployment of Gigabit Ethernets in metropolitan areas creates new opportunities to save costs by converging data and telephone services. The primary question of our study is whether emerging metropolitan networks can meet the QoS requirements necessary to connect GSM and UMTS base stations. These requirements on delay, jitter, and loss are significantly(More)
Self-organizing wireless metropolitan area networks connecting portable GSM/UMTS base stations are a valuable asset to rescue forces in disaster recovery. These networks can be formed by routers employing multiple commercially available IEEE 802.16-2004 interfaces. In this paper, we present and evaluate an algorithm for self-organized topol-ogy construction(More)
T To op po ol lo og gy y C Co on ns st tr ru uc ct ti io on n i in n t th he e T TO OW WN N P Pr ro oj je ec ct t T Te ec ch hn ni ic ca al l R Re ep po or rt t 2 27 71 1 Executive Summary In this report, we propose and evaluate an algorithm for self-organized topology construction and channel allocation of mesh routers. The routers are equipped with two(More)
The goal of the TOWN project is to lay the technical foundations for ASCOM to build routers with multiple IEEE 802.16-2004 interfaces that can form wireless multi-hop networks for disaster recovery in a self-organized way. The main scope of this report is the design of a protocol that implements a previously proposed topology construction and channel(More)
M Me es sh h N Ne et tw wo or rk k T To op po ol lo og gy y C Co on ns st tr ru uc ct ti io on n a an nd d C Ch ha an nn ne el l F Fr re eq qu ue en nc cy y A Al ll lo oc ca at ti io on n i in n t th he e T TO OW WN N P Pr ro oj je ec ct t T TI IK K-R Re ep po or rt t 2 25 55 5 Executive Summary The TOWN project addresses employing mesh routers with(More)