2,116 research outputs found
Center problem for a class of degenerate quartic systems
This paper, using pseudo-division algorithm, introduces a method for computing resonant focus numbers of a class of complex polynomial differential systems, establishes the necessary and sufficient conditions for existence of a center for a class of complex quartic systems with a degenerate resonant singular point
Precise Request Tracing and Performance Debugging for Multi-tier Services of Black Boxes
As more and more multi-tier services are developed from commercial components
or heterogeneous middleware without the source code available, both developers
and administrators need a precise request tracing tool to help understand and
debug performance problems of large concurrent services of black boxes.
Previous work fails to resolve this issue in several ways: they either accept
the imprecision of probabilistic correlation methods, or rely on knowledge of
protocols to isolate requests in pursuit of tracing accuracy. This paper
introduces a tool named PreciseTracer to help debug performance problems of
multi-tier services of black boxes. Our contributions are two-fold: first, we
propose a precise request tracing algorithm for multi-tier services of black
boxes, which only uses application-independent knowledge; secondly, we present
a component activity graph abstraction to represent causal paths of requests
and facilitate end-to-end performance debugging. The low overhead and tolerance
of noise make PreciseTracer a promising tracing tool for using on production
systems
Quasi-Eigenstate Evolution in Open Chaotic Billiards
We experimentally studied evolution of quasi-eigenmodes as classical dynamics
undergoing a transition from being regular to chaotic in open quantum
billiards. In a deformation-variable microcavity we traced all high-Q cavity
modes in a wide range of frequency as the cavity deformation increased. By
employing an internal parameter we were able to obtain a mode-dynamics diagram
at a given deformation, showing avoided crossings between different mode
groups, and could directly observe the coupling strengths induced by ray chaos
among encountering modes. We also show that the observed mode-dynamics diagrams
reflect the underlying classical ray dynamics in the phase space.Comment: 4 pages, 4 figure
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