Sep 29 2014

Pasting Windows Paths in Vivado

Published by under coding

If you’re using Xilinx Vivado or another tool with a Tcl interpreter in Windows, sometimes you want to paste a path from the file system, for instance to cd into a directory. Tcl treats backslashes as escape characters so just doing

cd c:\some\dir

Isn’t going to work. The easiest fix is to enclose your path with curly braces.

cd {c:\some\dir}

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Apr 30 2014

Emacs Org-mode copy visible text

Published by under coding

Emacs Org-mode is a great note taking tool, that stores everything in text, a format you’ll never lose access to. If you use Emacs Org-mode to organize notes, you often end up with a tree of partially collapsed nodes. For instance, you might want to chart out a meeting agenda, with notes under each item.
* Meeting today
** Project alpha...
*** Schedule
Some notes here about the schedule,
*** Deliverables...
** Project beta...

When it’s time to send out the agenda, you only want to email the upper nodes, but normal copy gets all the notes as well. Turns out you can copy only the visible text to the clipboard with C-c C-x v

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Nov 11 2013

The script for Episode VII

Published by under space

A very advanced Bespin mining vessel emerges from a wormhole and confronts a Star Destroyer. Darth Vader sacrifices himself so his twin children can escape in lifeboats. The action moves to Tatooine, where a young fuck up named Luke Skywalker drives his uncle’s hover camaro over a cliff. Fifteen years later, Luke is involved in a Mos Eisley brawl and an older Rebel Alliance officer named Ben Kenobi takes an interest in him, encouraging him to turn his life around and join the rebels. He does so, becoming an officer just as the Bespin mining ship reappears. Luke and his training crew arrive too late to save Alderaan, (homeworld of his rival/friend/secret twin sister) from destruction by the mining ship. They later cook up a crazy plan that makes the mining ship explode and earns them all medals in a weirdly awkward ceremony …

Episode VIII – There is a mole in the rebel alliance named Boba Fett …

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Oct 31 2012

Our New Downtown Library

Published by under AnnArbor,books,education,elections

I’m really excited about the plans to build a new downtown library, and I wanted to share some of my personal thoughts about this.

The Library has developed a concrete plan for how a new library will benefit this community, arrived at through 5 years of analysis and public comment. Among the items on the capability side that are not possible in the current building:

  • an auditorium for free lectures, film, performance and discussion
  • a large quiet reading room
  • access to the local history collection (currently offsite)
  • spaces that can handle messy hands-on programs (like electronics workshops, for instance)
  • a café
  • a youth area that can simultaneously accommodate home school groups and story times (currently a daily conflict)
  • more computing resources

Besides lacking these capabilities, the current library has a number of fundamental problems – energy inefficiency, poor lighting, outdated HVAC, unbalanced ducts, elevators and roof at end of life, and a fundamental design that is not accessible to those with disabilities (the elevator opens onto a descending staircase, for example), nor is it able to support additional technology infrastructure.

Based on my experience with setting up Ignite in Ann ArborI think a small auditorium at the library would be a huge boon for the community. Spaces like that are difficult to find in town, most venues are too large and too expensive for events like Ignite – events based on a passion for knowledge, not profit. In addition to talks by community members and authors, think of the opportunities for film, theater and music performance in a free and welcoming space. The library tries to hold some events like this, such as the Story Collider, but that event has ended up offsite at Live at PJs recently because the crowd cannot fit in the basement multipurpose room, which is not a great venue for this type of free event. Overflows are often handled by simulcast in another room in the building, which is not the same experience. Some say the average event size fits in the multi-purpose room just fine – but that’s an average, there are much larger events, and the room is limiting the event sizes because it is too small!

All events at the library are free to attend, regardless of who is holding them. It is one of our few and dwindling public commons. I certainly do not agree with the comments I see that we should replace the library system with Kindles and pay through the nose for content that can be revoked at any time. That is not, and has never been, the point of the library. Our library system, AADL, has been extremely innovative with the resources they have. You can sign out framed art printselectronic music tools, and telescopes. I recently took my daughter to a 1/4 scale timber frame barn raising.

AADL extensively studied doing a renovation instead of constructing a new building. However, the above capabilities will not fit into the current footprint of the building, unless one was planning to remove books, which I do not support. Books are still very important, and I love them. The current building cannot expand its footprint and it cannot have floors added on; the2007 construction study showed that additional load is not possible. The only possibility for something like a renovation, was the 2007 option to replace the front portion of the building with a 4 story addition.  Construction cost modelling of this option showed that costs for this would rise to 90% of the cost of a new building, and provide a far inferior result.  Recycling of the current building materials will be prioritized and a new building will be much more ecologically sustainable than the current patchwork, built in three pieces over 55 years. The site cannot be sold because of the separation agreement with the Ann Arbor Public Schools in the nineties.

AADL has shown more than a decade of strong fiscal responsibility. They have built three beautiful branch libraries out of the operating millage within schedule and budget, branches which are sustainable and have low operating costs. They voluntarily reduced their operating levy to taxpayers in 2009, and they are a separate entity from the city. Interest rates and construction costs are at record lows right now – it will never be cheaper to embark on this project, which will cost $65 million funded by a 0.47-0.56 mil property tax ($47 to $56 per year for a $200k market value home – a dollar a week). In fact, interest rates for municipal bonds are comparable to the long term inflation average of 2-3%, so the financing is likely to be close to cost-free in real dollars.

I think that the AADL is the bedrock of this community’s intellectual and civic life, and I want to make sure it continues to innovate and improve into the future. It *must* thrive and grow, and you can help on Nov 6th at the bottom of the ballot by voting Yes for the new downtown library, and voting Yes for living in a town that values learning, culture, and human connections.

For additional information, see

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Aug 22 2011

Why aren’t Social Security numbers cryptographic public/private keys?

Published by under technology

I’m not a security person and I don’t know what I’m talking about. Stories about children’s Social Security numbers being stolen and used without detection until they come of age and other similar tales are legion, and the problem is almost always Social Security numbers lying around unsecured at some service provider or company.

What if instead of using a single number, you protected a private SSN key, signed a token with it, and provided your public key and the token to whoever it is who thinks they need SSN verification? If you’re applying for a loan, you would send the bank this signed token, and they could verify your identity with your public key. Then if your bank was hacked, they don’t actually have your private SSN or the ability to generate new tokens with the information they’re storing. I guess you’d have to make sure that whatever was signed with the private key was unique to that institution though, so that the exact same signed token wouldn’t be accepted by someone else.

People may still leave their private SSN lying around, but it seems it would be significantly more secure than the current system of spreading it among a large number of organizations, where you are vulnerable to the security practices of the weakest link.

Problems: everyone needs a computer, so it’s not as accessible to the general public. Could you make the private key a physical object and have some kind of cheap handheld device for signing a hardware token the bank / doctor / etc sent you, which you would then send back? You’d have to guard against counterfeit signature devices, but maybe the SS administration could send a trusted signature device with your physical SSN key?

Now maybe there are issues with something like this when the service provider is trying to use your SSN to query 3rd parties. For instance, a bank wants your SSN so they can turn around and query credit reporting agencies, so your signed token from the bank wouldn’t mean anything to the third party. However, the bank could get the unique token from the credit reporting agency, and hand it to you to sign, then hand it back to the agency for the credit history perhaps?

I’m not sure how workable something like this would be, but it certainly seems like there must be some scheme which would work better than the current system.

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Jun 04 2011

Sugar Cube QR Codes

Published by under design,image processing,technology

Here’s the rest of the pictures from the rest of our Sugar Cube QR Code experiment at the A2 Mini Maker Faire. I enlisted the help of a number of 3-10 year olds to glue sugar cubes onto an (almost) properly sized template, and managed to end up with a scannable code! Ed Vielmetti and Jamie Lausch and I then piled a number of additional cubes on top to make a 3D city scape that was still scannable in it’s final form.

This was a proof-of-concept hatched this week to illustrated making QR codes from mixed media. If you are interested in doing something similar, we are organizing an event partnership between a2geeks and North Quad to hold a QR code art show called NQRT in October. Open submissions for QR code scannable art made of things. More details to follow, still in the planning stages. Follow @nqrt for details and developments.

Update: Jamie and Matt from SI did a great job printing the template! What other materials do you think would work?

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Mar 08 2011

Oishinbo A la Carte

Published by under food

Since Jerzy Drozd‘s talk at Ignite 5 I’ve been looking on and off for some kind of comic to get into that doesn’t involve tights. Fortunately there’s a lot to choose from, and this past Sunday at AADL I stumbled across Oishinbo – Japanese Cuisine. I’m in love.

If you fondly remember Morimoto angrily yelling “HE IS NOT A CHEF!!!” at Bobby Flay at the original Iron Chef USA special event after he stood on his cutting board, then this is the comic for you. It has it all. The over-wrought characters, the mild sexism, and the fanatical attention to culinary detail. We’re talking about making the perfect rice by picking out the malformed grains with tweezers.

The main characters Yamoaka and Kurita (later his wife – hilarious!) are in charge of the Ultimate Menu project at Tozai News. They have to explore the true nature of Japanese cuisine for the paper. However, at every turn they are confronted by Kaibara Yuzan, Yamoaka’s father and rival (!). “IT’S A SICK JOKE THAT SOMEONE WHO DOES NOT EVEN UNDERSTAND THAT BASIC CONCEPT HAS BEEN PUT IN CHARGE OF THE ULTIMATE MENU. YOU HAVE NO RIGHT TO BE TALKING ABOUT FOOD!”

It’s great, and there’s a whole series exploring different aspects of food.

Jerzy’s talk:

I’m still looking for some hard sci-fi comics.

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Feb 14 2011

Building Museums to Survive Once-In-200-Year Catastrophes

Published by under design,history,sustainability

This news from Cairo is heartbreaking:

A full inventory of the Egyptian Museum has found that looters escaped with 18 items during the anti-government unrest, including two gilded wooden statues of famed boy king Tutankhamun, the antiquities chief said Sunday.

I can’t help but think of Neal Stephenson’s Anathem, where mathic monasteries preserve knowledge for millenia while skyscrapers rise and fall outside the walls. I think we need to take a long view on museum design and design them more like bunkers.

I’m not saying they should be remote and inaccessible to the public, but that they should be designed in a way that makes it possible to lock them down in the event of civil unrest or other catastrophe. What is the mean time between riots in any given city? Even if it is 100 years, if you’re storing 4000 year old artifacts you have to be able to survive these rare events or eventually there won’t be any artifacts left. That means no glass ceilings.

Even if your museum is situated somewhere that seems stable and safe, can I ask you what a safe location looks like on a 500 year time scale? Even if you’re the Royal Ontario Museum in civilized Toronto, how long until there’s a Stanley Cup riot that gets out of hand? OK, true, that’s probably more of a 1000 year timescale.

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Feb 12 2011

Geographical Distribution of Standing Ovations

Published by under music

It occurred to me while at a UMS performance whether anyone has ever studied the geographical distribution of standing ovations. Where are they most likely? Ann Arbor is not a traditional major arts center but it does get some decent performances coming through town.

So in places far from major arts centers, are audiences more likely to give a standing ovation because they really appreciate seeing a reasonably good performance? Or are they more stingy with them than New York because they don’t want to seem like provincials that will applaud anything?

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Sep 24 2010

Just saw Uranus in person for the first time

Published by under space

I had stashed some Galileoscopes at the end of last year, primarily for youngsters, and just put the one I kept together last weekend. It’s been cloudy all week, but finally tonight it’s clear, and it works really well for $25, mounted on a standard camera tripod. It has a 25x and a 50x lens configuration.

You can see the moon quite well, and looking at Jupiter I could also easily make out the four Galilean satellites, three of them lined up very uniformly on the right (lens flip). I came in to take a look at Stellarium to see what it should look like, and realized that Uranus was right there, just to the upper left of Jupiter. This is an unusually close alignment. I’ve never had a good telescope, and this $25 piece of plastic didn’t seem good enough either, but given how easy it would be to locate with the close landmark of Jupiter I ran back outside to take a look. Accounting for the lens flip, I could make out a faintly blue point just at the edge of the field, if Jupiter was still in the field (see below). Later checking on Stellarium indicated Uranus was a little over 1 degree from Jupiter, and the Gallileoscope 25X field of view is 1.25 degrees, so I’m quite sure that was it.

Not bad for a $25 scope. And they’re still available – a great and inexpensive way to introduce a young person to astronomy. Also, putting it together is a good learning experience in itself.

Uranus - easy to find this week.

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