Free symmetry software

Lee_Teschler — Fri, 13 Jun 2008 13:05:00 GMT

You may remember from your calculus classes that symmetry can sometimes be used to solve equations that at first look daunting. But some symmetries are so complicated that they are tough to spot, even for a computer. University of Michigan researchers recently reported a breakthrough in this area. From the release:

In less than a half-second, the new software captured 1083,687 different symmetries in an Internet connectivity graph of routers around the world. A symmetry in this graph signifies a way the routers could be shuffled that wouldn't change the operation.

Previous methods timed out in the 30 minutes they were given to generate results in these experiments. Darga said it would take these older programs days to solve such a complicated problem. In searching for symmetries in the road networks between cities and towns in Illinois, the new algorithm captured the 104,843 symmetries in less than a half-second, whereas the most robust previous algorithm took 16 minutes.

They are even giving the software away. You can request a copy here:

http://vlsicad.eecs.umich.edu/BK/SAUCY/

headline:A Third of Public-School Students in Mass. Need Remediation at College

Lee_Teschler — Fri, 29 Feb 2008 12:12:00 GMT

The headline from the news blog of the Chronicle of Higher Education screams that a third of public school students need remediation at college. Read the item, though, and it is clear that the there is less to the headline than meets the eye, and the news may be less alarming than it first appears.

First, they are only referring to public school students who continued on to college. So it is obvious that the proportion of public school graduates who needed remediation is less than one third. It is actually one third of those who continued on to college, not one third of the total population of public school graduates.

And the report is not clear on whether the figure only references those who went on to four-year schools, or those who also went on to community college. It would seem to include both groups. If that's the case, therein may lie an explanation for the large amount of remediation. Most people continue on to four year schools to pursue a profession. Some continue on to community college to pursue a profession, but many more go there to get a vocation. There is a difference in preparation between the two groups.

Finally, it turns out that what they mean by "needing remediation" is that the student took at least one remedial course. It would be interesting to see how many took one and only one remedial course.

It would also be interesting to find you what passes for a remedial course these days. I know what it was like back in my day. If the college admitted you with math SATs that weren't quite up to snuff, you might have wound up in a remedial calculus course. They covered the same material as the regular freshman calculus course and took the same exams. But they met more frequently to give more classroom time, and they were run by the same teaching fellows running the regular classes. Their "remedial" nature was minimal.

http://chronicle.com/news/article/4057/a-third-of-public-school-students-in-mass-need-remediation-at-college-report-says?utm_source=at&utm_medium=en

from the editor's desk : calculus

Free symmetry software

headline:A Third of Public-School Students in Mass. Need Remediation at College