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The Bridge Blog
A dialog about our new bridge and these web pages

Overview. As a pointy-headed university professor, my weekend project of bridge photography and building these web pages generated many questions and introduced me to just-in-time learning. I enjoy chasing my curiosity and want to identify ways to encourage younger learners to also enjoy curiosity chasing and learning.

Learning usually requires repetition while forgetting occurs when I infrequently use information. Many young learners do not understand the importance of repetition. Weekly visits to the bridge provided the repetition necessary to detect changes in the bridge and consequently generated many questions and opportunities for learning. Over the course of the bridge project, I had access to few experts for answering questions. Rather than a liability, this became an asset and pushed me to improve my search skills with Google. Soon, I found that answers to questions encountered during my weekly photo shoots were often only a Google-search away - (see Restoring the Joy in Learning). Consequently Google + Internet became dependable extensions of my memory.

The bridge story is a work in progress and is evolving from a simple collections of photographs to an experiment with Internet-centric just-in-time learning. Insights I gain from you will find their way into the learning centers of MUSC. Palmetto Bridge Constructors, a joint venture between Tidewater Skanska and Flatiron Constructors, as well as High Steel Structures, Freyssinet, the SCDOT and the Federal Highway Commission Office of Bridge Technology guided much of my learning. I also learn from many of you and from Google-linked resources. More important is the e-mail encouragement I receive from many of you.

Sun, 29 May 2005

May 29, 2005: Learning from the bridge and the Internet

Our new Cooper River Bridge is a great motivator for learning. That said, Google + the Internet are great resources for both learning and for remembering. (If you see a disconnect, visit the forgetting curve.) Earlier this week I faced the challenge of learning how to stitch photos together in order to make a panoramic presentation. The results (see below) were ok, but the junction of the images was apparent, particularly the junction of the left image and its neighbor. Since this is Charleston, 2nd class results are simply not acceptable, so I faced another challenge - how to improve the blend between the images.

Last week, I found an open source program hugin - a Panorama Tools GUI available from Sourceforge. Last night, I started my search with Google and found a link to another Sourceforge offering, Enblend, as well as a tutorial about blending exposures using Gimp. I visited the enblend web site and sure enough, there was both an example, based on Hugin, which I used last week to build the panoramic image as well as the code for computing the blended image. So I downloaded the code, and another surprise, it compiled without an error. I then followed the instructions and created the above result. Needless to say, I was grinning from ear to ear.

A word about open source software. I have been associated with open source resources since I obtained our Unix license at Duke in 1974. Although open source software is often called free software, it requires some effort to build, integrate and use. Richard Stallman, a champion of the open source movement, prefers that the term, free, refer to the personal liberty that is associated with the use of open source software and not its cost.

These bridge web pages reflect the freedom and liberty associated with being able to access and integrate open source software in producing a result. For example, my web server software is Apache and my desktop system runs Fedora Linux. At the application level, Gimp is my image processing tool, now joined by ImageMagick, Enblend and Hugin.

posted at: 16:12 | path: | permanent link to this entry

Wed, 25 May 2005

May 25, 2005: A view from the top - Exploring photo stitching

Sunday found me on the bridge again to check out what had happened the night before. What had happened was a lot of paving on the outside south lane. Also Murray and Wade were deep in discussion and suddenly there was an opportunity to visit the top of the west pylon. This time, I was determined to take a series of photos of the horizon and later to try to piece them together to make a panorama.

I was in luck - the temperature was cool, the humidity was low and the view was perfectly clear. At home, I found an open source program hugin - a Panorama Tools GUI available on sourceforge, a really great resource where many many people manage open source development projects (including my IT Lab at MUSC). So I downloaded the software, installed it, followed their how to tutorial and tried to piece two images together. It worked the first time - so I tried 4 photos stiched together. It worked as you can see above.

Whether it is the bridge project or open source software or research, Google, as the card catalog and the Internet, as our library, level the playing field such that everyone has access to the same resources. Only our energy level and curiosity make a difference.

posted at: 10:00 | path: | permanent link to this entry

Mon, 16 May 2005

May 16, 2005: Pylon airflow
Sometimes you never know when your past will catch up with you. When I first came to MUSC, our outsourced IT support folks could not execute within my frame of reference - Internet-centric learning. So I formed the Information Technology Laboratory, aptly named the IT Lab by Nafees BinZafar, one of my first. The IT Lab was set up to give me the freedom to execute within the web world and I can honestly say that I have learned more from them than they from me. I simply ignited their curiosity fuse and then got out of their way. One of the few rules in the IT Lab was that you cannot resign - only graduate.

Nafees and Nathan are two of my graduates that now work for Digital Domain - doing systems and animation infrastructure - and they continue to contribute back to our IT Lab. Today Nafees wrote and confessed of being confused by the design of the tops of the east and west pylons. Being a well trained graduate of my IT Lab, he did a simulation to explore two different alternatives. In his words

Hi Frank.  I've been looking at your cooper river bridge pictures.  
And I wondered why the tops of the towers were indented, and not flat.  
I guessed it had to be for aerodynamic reasons, but I couldn't find anything 
on the web about the exact reasons.  So I ran a simulation.  I couldn't 
find the exact dimensions for the tops, so I eyeballed it from your 
pictures.  For comparison I modelled a tower with a flat top.  
I suppose I should have done one with a pointed top also.

I'm attaching movies of the top view and the side view of the simulations.  
The wind is blowing in at about 22 mph.  The massless tracer smoke is 
generated by 2 sources; 1 on top, and 1 on the leeward side.  The sims 
didn't really show anything numerically conclusive.  My simulation 
resolution is much too low for that.  The vortex shedding frequency seems 
a little bit higher in the "flat-top" configuration, and downstream 
the flow is more turbulent.  Also, there is a very substantial pressure 
drop in the indented region.  So I suspect that you will have some 
really good photo-ops of condensation trails on a cold and windy day. 
Here are the two videos (avi and mpg format). As with any collaborative effort, there are issues. In this case, the avi or mpg files may require some care when displaying. We are exploring alternative formats.

posted at: 14:23 | path: | permanent link to this entry

Sun, 08 May 2005

May 8, 2005: Our extended bridge family

It is all about people chemistry. New chemical compounds are impossible as long as the reagents live in their individual bottles. Mix them together, add a bit of heat (sometimes) and something interesting might happen. The same with people. When I sit in my office or home, bottled as a chemical reagent in the supply room, nothing interesting happens. When I get up and poke around, I collide with others, and the possibility of something interesting is amplified. So it is with our bridge project.

Earlier this week, Sandrine phoned me about a surprise birthday party for her husband, Oliver (who directs the local Freyssinet work). This was a complete surprise for me because Sandrine did not have my phone number. But being the resourceful woman that she is - she managed to locate it. Yesterday, we all gathered at Oliver's place - for wonderful afternoon of celebrations. We celebrated the birth of their daughter, Lucille, we celebrated the appearance of Oliver's mother-in-law, Jackie, who quickly became the energy of the party, and finally, we celebrated Oliver's birthday. There is a photo essay of course.



posted at: 14:46 | path: | permanent link to this entry

Fri, 06 May 2005

May 6, 2005: Exploring digital sketches
There comes a time when simply capturing the action of constructing the new Cooper River Bridge approaches blindly following a recipe - and I try to avoid falling into a rut. I have standard places that I go, standard sets of photos that I take and standard ways to process the images for placement in these web pages - all the ingredients of a rut. Several weeks ago I began experimenting with ways to alter the images so that they took on the characteristics of a sketch. I cannot draw an attractive stick figure, so for me, this was an opportunity to explore something that I was totally incapable of doing on my own.

When I look at a sketch, I see the outlines of objects the artist projects. So I started with processing an image with an edge detection algorithm. These algorithms compute the difference in intensity of adjacent picture elements (pixels). When the intensity difference is small, then the point appears black. When the intensity is large, then the point appears white. Consequently edges (where there is a large intensity difference) will appear as while lines. But an artist sketches with a black pencil, so I inverted the image - white became black and black became white. Because these are color images, edges are computed for each of the three colors - red, green and blue. I then alter the black-white range of intensities so that I get a more balanced image. The results, as seen here, are interesting. Bibi, an art history student at UC Berkeley and friend of our family finds that these transformations bring something new to the art table - an improvement beyond simply copying an artistic style.

posted at: 05:45 | path: | permanent link to this entry

Sun, 01 May 2005

May 1, 2005: Adventures with elevators and the traveler

Yesterday I met Murray Feldman and indirectly Bill Nesteruk and his company, Specialized Engineered Products Ltd. Bill creates these modern marvels that transport stuff horizontally (as with the bridge traveler) as well as vertically (or almost vertically) - i.e. the bridge elevators. Murray makes them work in the field. Again, design and engineering of the traveler and elevators generated for me, a quiet smile.

The traveler, used for cleaning and inspecting the underside of the bridge, is a necessity. Similarly, the four elevators that travel up and down the inclined surfaces of the east and west pylons, provide access to the pylon base, the crossbeam and the top. I experienced these elevators when I was learning from Freyssinet about building stay cables - but somehow the issue of traveling up and down an incline where the angle of the incline changes at the pylon crossbeam never caught my curiosity.

posted at: 10:00 | path: | permanent link to this entry

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frank.starmer at gmail.com

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