Light Bulb Efficiency Calculator

8/18/2012 UPDATE: From the comments, Andy pointed out that I had a mistake in my calculations. In the c_total equation, I should have divided by 1000, instead of multiplying by 1000. After he pointed this out, I checked the java script code as well. I had made an even more egregious mistake there. I had correctly divided by 1000 but I also had divided by power cost (dollars per kilowatt hour). I’ve now fixed the equation and the script. I also regenerated the results from the examples.

I am slowly upgrading the incandescent light bulbs in my house with more efficient compact fluorescent light bulbs. However the higher purchase price of the new bulbs has me wondering if they are actually “worth it.” I also thought whether an even more efficient type of bulb, perhaps an LED light bulb, would be better.


So, I set out to determine a value which would best quantify the “worth” of different bulbs and rank each based on this value.
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Dr. LaValle, Georgia Tech RIM Seminar Series

Last week, Dr. Steven M. LaValle, a Professor of Computer Science at The University of Illinois at Urbana-Champaign, presented as part of Georgia Tech’s Robotics and Intelligent Machines (RIM) Seminar Series. This was the second is a series of eight seminars spanning the Fall 2006 semester and I had the pleasure of attending and hear him speak.

Dr. LaValle structured his lecture around his new book, Planning Algorithms, which is available for free download here. He describes the book by saying:

This book presents a unified treatment of many different kinds of planning algorithms. The subject lies at the crossroads between robotics, control theory, artificial intelligence, algorithms, and computer graphics. The particular subjects covered include motion planning, discrete planning, planning under uncertainty, sensor-based planning, visibility, decision-theoretic planning, game theory, information spaces, reinforcement learning, nonlinear systems, trajectory planning, nonholonomic planning, and kinodynamic planning.

While he was there to present his entire book, he chose to focus on three areas of overlap between mechanical engineering, electrical engineering, and computer science which present “great potential for impact”: motion planning with differential constraints, feedback motion planning, and information spaces.
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Atlanta’s Historic Architecture

When I found out that my roommates and I would eventually have to move out of our West 14th Street loft, I began exploring different buildings around Atlanta. My hope was that I would find another historic space that would provide us with a similar atmosphere and lifestyle. I realized that with so many buildings to keep track of, I needed to compile a list complete with pictures, maps, descriptions, etc. I collected possible buildings as I rode around the city on my daily commute or sometimes I would explore with the intent of finding new places. I was specifically looking for late 19th and early 20th century industrial/commercial buildings. These were exclusively brick-and-mortar buildings, most of which served as infrastructure to Atlanta’s vast railway lines. I furthermore became interested in finding and cataloging some of Atlanta’s different neighborhoods and districts.

My list is horribly incomplete and only contains buildings which I, myself, have seen and photographed. I recorded the street address and then performed a Google search to find information about the availablity of each building. When possible I include a description of the building, its current status, and what I think is the correct name of the building. Those with the most appealing location and amenities are denoted with a red star.

Atlanta Historic Architecture List

Even though we have now found a place to live, I plan to continue to fill in this list including more detailed pictures and descriptions and expand it as I discover new structures around Atlanta.

Peaucellier-Lipkin Linkage

I created a Solidworks model of the Peaucellier-Lipkin linkage to better visualize the kinematics of the linkage and to document my Solidworks CAD capabilities. I modeled several parts: pins, links, and brackets. The brackets have zero degrees of freedom to simulate being secured to the ground. The links are of lengths 50, 75, and 150mm from axis to axis.

SolidWorks model of the Peaucellier-Lipkin linkage

I also generated a .gif animation to show the pure translation of the end joint (shown as the red pin). I have posted here all of the CAD files.

(7-Zip of complete SolidWorks parts and assembly)


I put together a list of my shoe collection. Each entry includes a picture and information, including style number, color, and when I bought them. This list is updated regularly as I get new shoes.

Adidas Response Trail X M
Colors: silver/blue/black
Style Number: 114582
Acquired:December 2005

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