Ulrich Fiedler

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The security level of networks and systems is determined by the software vulnerabilities of its elements. Defending against large scale attacks requires a quantitative understanding of the vulnerability lifecycle. Specifically, one has to understand how exploitation and remediation of vulnerabilities, as well as the distribution of information thereof is(More)
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)
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)
The precise, sequence-specific regulation of RNA synthesis is the primary mechanism underlying differential gene expression. This general statement applies to both prokaryotic and eukaryotic organisms, as well as to their viral pathogens. Thus, it is not surprising that genomes use a substantial portion of their protein-coding content to regulate the(More)
Electronic Commerce over the Internet is one of the most rapidly growing areas in todays business. However, considering the most important phase of Electronic Commerce, the payment, it has to be noted that in most currently exploited approaches, support for at least one of the participants is limited. From a general point of view, a couple of requirements(More)
Emerging Metro Ethernets create new opportunities to converge data and telephony services. However, to connect legacy telephony equipment, networks have to meet customary QoS requirements even at the presence of bursty data cross traffic. We show with analytical evaluation and simulation results that without appropriate mechanisms the QoS requirements(More)