TheBoohers.org
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Review: Our Kids
Following a polarizing election that has left many in my community surprised and confused, Robert Putnam’s “Our Kids” provides a refreshing collection of research and engaging anecdotes told with generosity of spirit. Perhaps more than any other modern voice, Putnam excels at describing American society in a bi-partisan way. He and his previous best-seller, “Bowling…
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Endurance and Altitude for Propeller-driven Aircraft
Lower altitude = higher endurance? At first glance this didn’t make sense to me. Air Force pilots will be the first to tell you that you don’t hug the earth en route to maximize your time on station, it is harder slogging in thicker air. At higher altitudes you have lower air pressure and colder…
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Review: Sapiens
Yuval Harari (יובל נח הררי) has written a scholarly, thought-provoking and crisply written survey of “big history” that he uses to preach his starkly different views of philosophy and economics. Dr. Harari teaches at the Hebrew University of Jerusalem where he wrote Sapiens in Hebrew and accomplished the very idiomatic translation himself. Provocative and broad,…
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July 4th Home Project: Thermostat Bracket
This post is about how to use design tools to save time and build nice stuff at home using computer controlled machines (CNC). In addition to describing my design process, I’ve also included the helpful references I found along the way. Our old thermostat was too small for our wall. I could have replaced the…
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Satisfiability modulo theories and their relevance to cyber-security
Cybersecurity and cryptoanalysis is a field filled with logic puzzles, math and numerical techniques. One of the most interesting technical areas I’ve worked goes by the name of satisfiability modulo theories (SMT) and their associated solvers. This post provides a layman’s introduction to SMT and its applications to computer science and the modern practice of learning…
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Basement Framing with the Shopbot
Framing around bulkheads is painful. It is hard to get everything straight and aligned. I found the Shopbot to be very helpful. There are three problems I was trying to solve: (1) Getting multiple corners straight across 30 feet, (2) nearly no time and (3) basic pine wood framing would sag over a 28″ run.…
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DIY Roulette Wheel and Probability for Kids
My daughter had to make a “probability game” for her fifth grade math class. She has been learning javascript and digital design so we worked together to design and build a roulette wheel for her class. First, she drew out a series of sketches and we talked it over. She wanted a 0.5 inch thick…
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Weaponizing the Weather
“Intervention in atmospheric and climatic matters . . . will unfold on a scale difficult to imagine at present. . . . this will merge each nation’s affairs with those of every other, more thoroughly than the threat of a nuclear or any other war would have done.” — J. von Neumann Disclaimer: This is…
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Kids Lego table: Case study in Automation for Design
Motivation I had to upgrade the Lego table I made when my kids were much smaller. It needed to be higher and include storage options. Since I’m short on time, I used several existing automation tools to both teach my daughter the power of programming and explore our decision space. The goals were to stay…
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The Hierarchical Dirichlet Process Hidden Semi-Markov Model
In my work at DARPA, I’ve been exposed to hidden Markov models in applications as diverse as temporal pattern recognition such as speech, handwriting, gesture recognition, musical score following, and bioinformatics. My background is in stochastic modeling and optimization, and hidden Markov models are a fascinating intersection between my background and my more recent work…
Got any book recommendations?