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InTheLoop | 06.08.2015

June 8, 2015

Alvarez Fellow Juliane Mueller Giving Two Talks on Optimization in Canada this Week

Juliane Mueller, the 2014 Computing Sciences Alvarez Fellow at the Center for Computational Sciences and Engineering, this week presents two talks in Canada on optimizing simulations. Mueller’s area of expertise is developing algorithms to optimize “black box” simulations, so named because no description of the objective function is available. This optimization, using smaller samples of full-size simulations, helps researchers make more effective use of computing resources. In Ottawa, Mueller will give a talk as part of Carleton University's Systems and Computer Engineering seminar series. After Ottawa, she travels to Montreal to present “MISO: Mixed-Integer Surrogate Optimization Framework” at CORS/INFORMS 2015, the joint international meeting of the Canadian Operational Research Society and the Institute for Operations Research and the Management Sciences. Mueller’s talk focuses on her recently developed algorithm framework for global optimization problems that have computationally expensive black-box objective functions and whose variables are mixed-integer.

Self-Assessments Due Friday, June 12

Don't forget that employee self assessments are due Friday, June 12. As last year, self assessments must be completed and submitted online via Google docs. In May, employees received links to their individual documents. Once your assessment is complete, you must submit it to your supervisor for review via the »CS Performance Review Center web page. Important "dos and don'ts," instructional videos, links and other information can also be found there.

This Week's CS Seminars

»CS Seminars Calendar

Transport Segment Delay Estimator (TSDE)

Wednesday, June 10, 1:00pm - 2:00pm, Bldg. 50B, Room 1237 (NOC)
Kathleen Nichols, Pollere Inc.

The delay experienced by application packets is a powerful Internet diagnostic.  Network problems (like bufferbloat or high loss rates) and end-node problems (like receiver or sender window limits) are both visible in packet round trip delays. Round trip delays have long been measured by end-node protocols to diagnose and repair loss. But  this high quality diagnostic information is only available to the end nodes while other network elements have made do with less capable measures such as the ping matrices produced by an active probing mesh.

Pollere has developed tools that extract high-quality round-trip and one-way delay information from passively collected application packet samples. The sampling can be done anywhere in the network and doesn't require samples from both directions of a flow (e.g., the tools work in the presence of asymmetric routing and multipath). Because the information is mined from application traffic, it measures everything that happens to the that traffic. So, for example, samples taken on the ESNet end of a campus peering link could be used not only to identify prefixes experiencing significant bufferbloat but also to localize the bloat, determining whether the bottleneck was inside the campus network, in ESNet, or on the path to the remote destination.

This work is supported by the DoE under an SBIR grant. The approach has so far been validated against simulation traces, pcap packet traces, both live and from measurement archives, and from lab experiments. We are looking for more validation opportunities.

Link of the Week: CERN Presents 'Seeing the Invisible'

Subatomic particles are far too tiny to see, so over the years physicists have devised ingenious ways to detect and visualise them, often forming beautiful patterns and pictures in the process.  From early experiments with cloud chambers to state-of-the-art animations of Higgs-boson decays, data visualisation in particle physics has come a long way. Here are just a few of the most striking images of particle interactions - or "event displays" - from over the years. »Read more.