Learn More
We propose a linear regression method and a maximum likelihood technique for estimating the service demands of requests based on measurement of their response times instead of their CPU utilization. Our approach does not require server instrumentation or sampling, thus simplifying the pa-rameterization of performance models. The benefit of this approach is(More)
In this paper, we propose simple performance models to predict the impact of consolidation on the storage I/O performance of virtualized applications. We use a measurement-based approach based on tools such as blktrace and tshark for storage workload characterization in a commercial virtualized solution, namely VMware ESX server. Our approach allows a(More)
We propose a novel admission control policy for database queries. Our methodology uses system measurements of CPU utilization and query backlogs to determine interference between queries in execution on the same database server. Query interference may arise due to the concurrent access of hardware and software resources and can affect performance in(More)
 Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has many advantages for the diagnosis and follow-up of hypertension at all ages. This technique has so far not been documented as applicable to the very young. We studied the feasibility of ABPM in 61 healthy children and in 40 patients with renal diseases and/or hypertension, aged less than 6(More)
Wir berichten über ein 3jähriges Mädchen, das wegen statomotorischer und mentaler Retardierung, generalisierter Muskelhypotonie und übermäßigem Wachstum zur klinisch-genetischen Diagnostik kam. Zytogenetisch wurde eine De-novo-Deletion 22q13 festgestellt. In der Literatur wurden 7 Patienten mit einem ähnlichen Phänotyp beschrieben. Diskussion: Es ist zu(More)
Popliteal synovial cysts (Baker’s cysts) are a common occurrence in children and adults. Synovial cysts in other locations and/or with atypical extension are less common and may be confounded with tumors or other medical conditions. In this article we describe the underlying disease, clinical presentation and clinical course in six children with a sudden(More)
We propose simple models to predict the performance degradation of disk requests due to storage device contention in consolidated virtualized environments. Model parameters can be deduced from measurements obtained inside Virtual Machines (VMs) from a system where a single VM accesses a remote storage server. The parameterized model can then be used to(More)
In recent years, a new generation of high repetition rate (~10 Hz), high power (~100 TW) laser systems has stimulated intense research on laser-driven sources for fast protons. Considering experimental instrumentation, this development requires online diagnostics for protons to be added to the established offline detection tools such as solid state track(More)
Within the scope of the European research and education network project GEANT2, including a framework for performance measurements, the need for statistical analysis and interpretation of network performance metrics has to be satisfied. Following the IETF approach, a measurement system for metrics as one-way-delay (OWD), OWD-variation (OWDV) and packet loss(More)
We propose a trace-driven approach to predict the performance degradation of disk request response times due to storage device contention in consolidated virtualized environments. Our performance model evaluates a queueing network with fair share scheduling using trace-driven simulation. The model parameters can be deduced from measurements obtained inside(More)