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OceanStore is a utility infrastructure designed to span the globe and provide continuous access to persistent information. Since this infrastructure is comprised of untrusted servers, data is protected through redundancy and cryptographic techniques. To improve performance, data is allowed to be cached anywhere, anytime. Additionally, monitoring of usage(More)
Overlay network monitoring enables distributed Internet applications to detect and recover from path outages and periods of degraded performance within seconds. For an overlay network with <i>n</i> end hosts, existing systems either require <i>O</i>(<i>n</i><sup>2</sup>) measurements, and thus lack scalability, or can only estimate the latency but not(More)
Overlay network monitoring enables distributed Internet applications to detect and recover from path outages and periods of degraded performance within seconds. For an overlay network with n end hosts, existing systems either require O(n<sup>2</sup>) measurements, and thus lack scalability, or can only estimate the latency but not congestion or failures.(More)
Scaling iterative graph processing applications to large graphs is an important problem. Performance is critical, as data scientists need to execute graph programs many times with varying parameters. The need for a high-level, high-performance programming model has inspired much research on graph programming frameworks. In this paper, we show that the(More)
Network Denial of Service (DoS) attacks are increasing in frequency, severity and sophistication, making it desirable to measure the resilience of systems to DoS attacks. In this paper, we propose a simulation-based methodology and apply it to attacks on object location services such as DNS. Our results allow us to contrast the DoS resilience of three(More)
We consider the efficient and accurate computation of Givens rotations. When <i>f</i> and <i>g</i> are positive real numbers, this simply amounts to computing the values of <i>c</i> = <i>f</i>/&radic;<i>f</i><sup>2</sup> + <i>g</i><sup>2</sup>, <i>s</i> = <i>g</i>/&radic;<i>f</i><sup>2</sup> + <i>g</i><sup>2</sup>, and <i>r</i> = &radic;<i>f</i><sup>2</sup>(More)
OceanStore is a utility infrastructure designed t o span the globe and provide continuous access to persistent information. Since t h i s i n f r astructure i s comprised of untrusted servers, data is protected through redundancy and cryptographic techniques. To improve performance, data is allowed t o b e cached anywhere, anytime. Finally, monitoring of(More)
Recently, two of the authors and their collaborators have developed an algorithm for computing a smoothly varying basis for an invariant subspace of a parameter dependent matrix A : R → R n×n. In this work, we extend the algorithm (i) to the case where n is large and direct methods are prohibitively expensive and (ii) to the case where eigenvalues collide,(More)