The Eclectic Technologist

A 60 Minutes report on Wall Street’s shadow market yields some interesting links:

• Copula - a multivariate joint distribution
• Collateralized debt obligations - unregulated (in 2008) asset backed security

Apparently, the Archimedean copula was used to price mortgage backed securities responsible for the 2008 financial meltdown.

Solar thermal is an attractive renewable energy source. Like other solar energy sources, it works, but is often not economically viable compared with established sources, such as coal. With rising energy costs and environmental concerns, there is increased interest in solar today.

The design above is a modern, reflective parabolic dish from Stirling Energy Systems. The dish produces about 25 kW, enough for about 10 homes in the US. This video on YouTube has more details. This video shows a small scale Stirling engine operating on solar power, similar to the full scale dish. Based on data from a large installation, it looks like 4 of these large dishes pictured above can fit in one acre, so that’s 100 kW/acre. The United States consumes about 440 GigaWatts. Roughly 18 million of these units spread over 6875 square miles would satisfy the entire US electric power requirements. That’s about 6% of the land area of Arizona, one of the two states with high solar insolation. It could be built using only 5.7% of the Sonoran desert.

The US congress is currently debating an economic stimulus package of $150 billion. If all of this money was used to build a solar array and each collector could be installed for under $50000, the power output would be equivalent to 44 Hoover dams, or about 20% of US electric power consumption. At current market prices, such an array could pay for itself in under 4 years. After that, the array could yield as much as $38 billion per year in gross revenue.

Of course, transmission of this power from the deserts of the Southwest to where it’s needed is a challenge, but it’s something to think about.

I really like Atmel AVR microcontrollers. They are simple, powerful, and inexpensive. There are lots of development tools out there, but I like AVR Studio. AVR Studio is made for Windows, but it works great inside Parallels desktop on my iMac. Parallels sees the AVRISP mkII USB programmer also. I had no problem upgrading firmware on the programmer. Now that I have a nice development environment set up, I might be able to finish some of the numerous hardware projects that have been languishing for years.

One minor problem I ran into was the clock rate on the ATtiny24. By default, the clock is divided by 8, so it runs at about 1 MHz using the internal RC clock. This was too slow for the default program clock, which caused programming errors. This is to be expected, but it ends up crashing Windows! After testing on a native Windows machine, I located the problem, reduced the programming clock and disabled the clock divider fuse. After that, everything was smooth. I even got AVR-GCC working using WinAVR.
I’ll post some of the circuits I’ve been working on in the coming months.

Many have observed the non-trivial nature of IE when viewing dynamic PDF documents. You know, the interesting ones that go beyond flat files on a static web server somewhere. It seems that IE will usually request a binary stream several times — often with unpredictable results. The only solution that is known to work reliably is to use the EMBED tag with IE and a regular link to your PDF (or dynamic web page that produces PDF) for all other browsers.

This particular problem exposed itself during a Websphere 5.1 to Websphere 6.1 migration. For some unknown reason, Websphere 6.1 decided to add a Cache-Control: no-cache header to the response. This caused IE to render a blank page — just what the user wanted We couldn’t eliminate the header, but using the EMBED tag solved the problem. Interestingly, pages with frames containing dynamic pages worked fine.

I’ve been busy with all sorts of things lately. I’ve been having fun with Smalltalk, Squeak in particular. It is really cool, IMHO. Squeak by example is a free online book that’s a great place to get started.

A lot of LDAP and security work has led me into the gory details of ASN.1, which is the underlying encoding standard for X.509 certificates among other things. It’s yet another variation of LISP S-expressions, as is XML, and most structured data schemes in widespread use. Lists and atoms, that’s all you really need.

Back in March of 1998, Network World invited me to write an article about Java in the enterprise. Java was still untested technology back then, so it had it’s detractors. Of course, I saw many benefits in Java, so I agreed to offer my opinion.

On the other side was a fellow by the name of Mike Sax, a strong Microsoft supporter. There were a number of predictions made by both us, some came true, some didn’t. You can read the article and judge for yourself how accurate our predictions were.

It might be hard to follow which part of the article I wrote and which part was written by Mike. I wrote the first half, which ends with “There is no doubt that Java is ready for the enterprise today. And in the coming years, there will be even more improvements.”. The remainder of the article is written by Mike Sax.

Electronic Design recently published my article on squegging and how to avoid it. I learned about its publication last week when a reader recognized my name from the first book I wrote in 1996.

I feel like we are living the Twilight Zone. If Rod Serling were alive today and still writing, his screenplays might look more like documentaries rather than science fiction. My feeling is that there has been a rise in mediocrity and few who question “opinion leaders” or their lack of hard facts and reasoning. My conclusion is that we are in a time of weak leaders.

Apparently, I am not alone. I was channel surfing last night and I stumbled on Tim Russerts show. He was interviewing Lee Iacocca, the former chairman of Chrysler. I caught the interview in the middle when Mr. Iacocca was talking about energy sources and alternative fuels. The subject is of great interest to me, so I listened. The interview was not limited to energy and cars. Mr. Iacocca was promoting his most recent book “Where have all the leaders gone”. The book has become an immediate best seller.

Iacocca is no longer a young man, he’s 82 now. The brash industrialist with a bold vision had been replaced by a humble and deliberate statesman. Without naming names, he quietly, but convincingly lambasted our current business and political leaders on all fronts. He gave credit where it was due, but challenged all of us to expect more and do more.

He talked of some our greatest achievements, the second world war, harnessing atomic energy, and landing a man on the moon. He believed that if we could do those things, we could solve our energy problems and develop better cars. It was absolutely inspiring.

After the interview, I started surfing again. Incredibly, C-Span was about to air a book signing speech by Lee Iacocca. He read an excerpt which is available online. It was really amazing. Hopefully, the video will be available online soon. I strongly encourage you to watch it and maybe read the book.

In 1990, I was an engineer working at the Space Sciences Division of the Naval Research Laboratory in Washington, DC. We were building a payload containing several scientific instruments designed to measure airglow in the upper atmosphere. The payload was to be mounted and flown on the Earth side of polar orbiting NOAA TIROS satellite.

Spacecraft design and development is somewhat unique. There is little margin for error, so lots and lots of testing is conducted to make sure everything works. Of course, this still doesn’t uncover all problems, as many spectacular spacecraft disasters have illustrated. I got involved in the project at about the mid point in development. Many of the major components were in fabrication and the flight software was already complete. There was little in terms of ground testing software, much of this testing was done by hand. This was not a large complex instrument, but it still required as long as three hours to fully test everything.

During the winter of 1990, there was a little down time. I had this crazy idea of automating most, if not all of the testing of our instrument. Armed with a wire wrap gun, an ISA bus prototype board, and Turbo C 2.0, I started working on the ground support interface board and software. The interface board connected the ground support equipment to an IBM PC/AT with 1 MB of RAM and a 20 MB hard drive. For testing automation, I developed a testing script language and compiler/runtime environment to execute test scripts.

Due to complications beyond our control, the experiment lost its ride on the particular NOAA satellite for which it was scheduled. The instrument, ground support equipment, and the PC/AT with all the software was packed up and placed in storage. The hope was that someday, another ride would come along and the instrument might be resurrected.

Last week, after nearly 17 years, I received an email from one of the remaining scientists on the project. It appears there is an opportunity to mount the instrument onto the International Space Station. It will be flown on a Japanese H-II Transfer Vehicle and deployed on the Experiment Module Exposed Facility.

From what I was told, the instrument, ground support equipment and that old IBM PC/AT were brought out of storage and unpacked. They fired up the PC and surprisingly it booted up. The next day, when the PC was powered on again, the hard drive spun briefly, and then ground to a halt. It failed completely. Apparently, there was no possibility of recovery.

Fortunately, there were some 5 1/4 floppy disks lying around with some backups of some of the software. Oddly enough, I also kept copies of some of it also, as it was one of the first, significant projects I worked on. The floppies were still readable after all those years.

Finding a PC that could accept an ISA board was a minor challenge, and the original DOS had to be replaced with FreeDOS. Turbo C 2.01 is now freely available, which is a big help. It sounds crazy, but it just might work…

I’ve been myopic since high school and I’ve never cared for glasses. Contacts are a little more convenient, but they have their drawbacks as well. Several friends have taken the lasik plunge, so I went for it.

I chose to schedule the procedure on a Wednesday afternoon. It’s really not a big deal, but I figured that Mondays are usually weekend recovery time. Who knows what level of binge drinking the doctor might have endured a day earlier. Fridays were also ruled out as most people want to get out early. Would you want to be the patient who held up happy hour?

I was a little lucky as there were few patients that day. Two optometrists were available to independently check my prescription. They came up with the same results, which was encouraging. I have some astigmatism in my left eye, which they wanted be sure I was OK with the correction. I guess some people might find it disorienting. I chose to have both eyes corrected. Monovision affects depth perception, which is important for pilots.

I couldn’t have asked for a better opthomolagist. He was very professional and personable. He assured me that if he felt there was any risk to my vision he would not even touch my eyes. Fortunately, I was a middle of the road case, so there were no worries. Still, just prior to the procedure, I felt compelled to ask if the doctor felt good and if he slept well the night before. Both answers were in the affirmative, so the show was on.

The procedure is really like science fiction, almost drive-thru in terms of efficiency. It takes only a few minutes and is largely painless. There is some discomfort when the doctor places the vacuum ring on your eyeball to hold it still. It’s just on the threshold of pain. The microkeratome cut is completely painless, I heard a brief buzzing and that’s it. The laser keratectomy is also painless, it takes only 30 seconds or so and smells like burning hair.

The recovery seems to vary quite a bit. Some patients feel a little discomfort, others find it almost painful. I was in the latter category. By the time I got home, my eyes were really tearing up as the topical anesthetic wore off. At the peak it felt like soap in my eyes. I should have taken the Tylenol I was given earlier. After a four hour nap, I was fine, with only minor discomfort.

Visual acuity comes and goes as the cornea heals. The variation can continue up to three months until vision stabilizes. After a few weeks, my vision was quite good, at least 20/20. Moisturizing drops really help, I even use the night time ointment.

I spoke with a customer service agent that had lasik surgery himself. Apparently, he was legally blind most of his life. His eyesight without glasses was 20/1400 and could only be corrected to about 20/240 with glasses. He couldn’t even drive in most states. After lasik, his eyesight was better than 20/20. Can you imagine going from legally blind to better than 20/20 vision in a matter of minutes? It had to have been a life changing experience. As you might expect, he was a strong proponent of lasik.

Overall, I am quite satisfied with the results. I would recommend it, if you don’t care for glasses or contacts. If you decide to do it, it’s probably a good idea to take a painkiller soon after the procedure to avoid any discomfort. Definitely use the rewetting drops often, your eyesight will be better sooner.