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Calculus and the bag of tricks (Chinese Room) approach

Trevor KleeHow to fix how people learn calculus: make calculus exciting again — “I only realized in college that I had been cheated out of a deep understanding of math and given a shallow collection of tricks instead.”

There is a hierarchy in learning math and Klee provides insight into why with his diagnosis of the problems in learning calculus, his suggestions for teaching it, and it’s history.


From physical standards to universal constants

The standard system of weights and measures is slowly advancing in its definition of official reference standards. From such things as the size of the King’s foot to the length of the forearm, the reference moved to platinum weights and bars. Now it is moving to universal constants of nature. Lubos has his take as
An SI vote next week may turn ℏ into a known constant.

The Science Magazine’s Adrian Cho has some fresh details: Metric system overhaul will dethrone the one, true kilogram

Most importantly, the 1-kilogram platinum-iridium alloy will be thrown away to the French sewerage system. Instead, one kilogram will be defined indirectly so that Planck’s constant will be h=6.62607015×10−34J⋅s exactly.
For the normal people, nothing will change at all. The physical constants will have more or less the same values, within error margins that are narrower than the normal people may distinguish, and the SI units will have the same meaning as before. The reform will only affect the life of the experimenters who were capable of measuring the constants with the globally competitive precision. They will have to translate their measurements to the new units and realize that it’s different numbers than before that will inherit the relative error margins.

there’s more. go see.

Unknown lessons from Baghdad

Experience can be a valuable teacher and the Army leverages their experience. They have a significant incentive. The Middle East wars are no exception. John Spencer says The Most Effective Weapon On The Modern Battlefield Is Concrete and explains some of the lessons learned. It’s about modern fort building with some new ideas for population control and management for safety and security. 


BNC history

Dan Maloney has a summary of the development of the BNC connector at Hackaday.

The connector that would eventually become known as the BNC connector when it was invented in the 1950s has its roots in two separate connectors developed in the 1930s and 1940s for the burgeoning radio and telephone industries.

Salati’s connector was patented in 1951 with the unexciting name “Electrical Connector.” Unlike its predecessors, it would not be dubbed the “S-Connector” but, in a gentlemanly gesture, it was called the BNC, for “Bayonet Neil-Conselman.” To support the RF work for which it was originally designed, the connector had a 50-ohm characteristic impedance; later, a 75-ohm version was made for the television industry. The connector is usable up to around 11 GHz, although it’s not ideal past 4 GHz or so owing to the slots cut into the conductor for the outer shield, which start to radiate signals.

post war technology boom stuff …

Swinging for the fences

These guys figured that the way to learn how to sail a boat was to start by building their own boat from trees on the family farm. The Mind of a Boat Builder – Acorn to Arabella is an interview with two 30 somethings who decided the thing to do with their lives was to build a boat. From their website:

We are building a 38’ sailboat from stump to ship, once completed she will take us around the world. We hope to inspire and educate as many people as possible along the way. Join us on our journey and let us show you that with a bit of dedication, good company and some old school smarts even the wildest of dreams can be made to come true!

Financing is via YouTube and Patreon and volunteers and contributions. It’s learn as you go, pay as you go, one thing at a time. There are many interesting stories here from what it takes to build an ocean worthy sailboat to an attitude towards life.

Microsoft, Github, and Zebra Stripes

The reaction to Microsoft acquiring Github says a lot about how tough it is for Microsoft to change the image it built in the 90’s. John Edwards explains Why Microsoft’s GitHub Deal Isn’t a Sign of the Apocalypse – “Fear not, developers. The open source development community will thrive, no matter who’s running the show.” Somebody’s got to pay the bills. Github is just the latest item added to Microsoft’s toolbox. Also consider .net, Windows 10, and VS Code.

The real reason Microsoft open sourced .NET By Mary Branscombe (CIO, 1/27/2016) – “DevOps, microservices, and the shift to containers and lightweight computing environments explain a lot about Microsoft’s position on .NET, open source and Nano Server.”

“The shift in how enterprises want to do development explains a lot about the open sourcing of .NET and ASP.NET as well. Partly, it’s to get the community involved – taking advantage of the ideas and expertise of developers who embrace open source projects.

Microsoft also wants to bring these technologies to Linux, in large part because of Azure. Running a cloud platform gives Microsoft an interest in Linux that goes far beyond the open source contributions the Windows Server team has been making to the Linux kernel so that distributions run will on its Hyper-V hypervisor.

Microsoft moves on open source .Net, ramps up multilanguage tools By Paul Krill (InfoWorld, June 27, 2016) – “Company embraces Linux, Mac OS, iOS, Android, and will show SQL Server on Red Hat’s Linux

In other words, there is a shift in revenue source from software sales to service and support. Github earned its income by providing cloud based project services for in-house commercial development efforts with the FOSS support a community relations thing. Microsoft is doing the same but it has a much broader base of services to provide better economic security.

All of this is part and parcel of revolutionary change in entrepreneurship. The first twenty years of Microsoft were ‘old school’ business. The last twenty has been a change from product development and sales to a product service support paradigm. Amazon, Google, Facebook and others have made their fortunes figuring out what it is that represents value and in how to leverage that value to income.

The revolution in the advertising and marketing business has, perhaps, been most visible. The information needs of these businesses has raised many concerns as newer technologies made a difficult and expensive proposition into a massive and inexpensive one. The economies of scale at Google and Facebook have moved many independent efforts to use their services.

Sales and financial transactions have also become more direct and less expensive. From paper checks in the mail to touch tone telephone bill pay to today’s online forms have all put more economy of scale into the process as well as streamlining processes.

Even the logistics have changed from Amazon’s wharehouses to Walmart’s grocery shopping online.

Microsoft is adapting. It’s change from sales of high price software towards using software as a marketing tool indicates that it sees how its source of profits must change. It’s making its technologies more easily available to a broader community as open source and cross platform. That builds image and that, in turn, provides exposure to its support and services.

The processes may have turned over but the revolution is not complete. There are still major changes ahead providing both opportunity and risk. We do live in interesting times.

Wildfires started by plinkers?

‘Tis the season: range grass is drying out and fires are a concern. The latest fad is to blame such fires on those out target shooting. To support this, there is a Forest Service study of ignition by rifle bullets. It is interesting and has data and theory worth considering. Careful reading also provides insight into reality and a proper assessment of risks. For anyone with experience target shooting in the wild or with trying to start a fire without matches or accelerants, the idea that there is significant risk of wildfires due to shooting warrants a great deal of skepticism. With proper care and due consideration, target shooting in the wilds is very rarely accompanied by shooting sparked fires. The lengths gone to in the study to support the idea of shooting based fires tells you what you should not do and what is not common practice.

The study used bullets deflected off a metal plate into a bed of dry peat moss as fragments and managed to detect some smoldering with non lead bullets from high power rifles. If you’ve tried to light a fire with flint and steel, you know that such carefully prepared tinder is a must and it still takes some careful management to turn that smoldering ember into a useful fire. The study notes that ” Peat moisture contents of 3-5%, air temperatures of 34-49 °C (98-120 °F), and relative humidity of 7 to 16% were necessary to reliably observe ignitions in the experiments.” Here “ignitions” means smoldering peat, not flames.

Also consider that bullets rip and tear targets, they don’t burn, char, sear, or cauterize targets. Even ejected cartridge cases that get inside clothing don’t burn holes in the clothing nor cause any significant skin burns and those cases are where most of the combustion of gunpowder occurred.

The study looked at the energy of a bullet as if all of the energy in that bullet was used to create heated bullet fragments rather than shared with the target. The assertion is made that “The discharge of a firearm involves the exchange of significant amounts of energy” and that is relative. The data shown indicate that a .45 ACP bullet has less than 1 BTU of energy leaving the muzzle while an AR-15 round has about 4 times that. A kitchen match produces 1 BTU of energy before it burns down to your fingers. Any scout knows that being able to start a campfire with only one match can be good bragging rights as it requires careful fire building and management.

The study does provide some insight into aspects of ballistics not often considered along with tables of data, pretty pictures, and the use of some fancy equipment. The analysis also covers a lot of ground and many factors. What is missing, though, is also important as it serves to qualify the analysis and to establish a basis for its relevance to whether or not there is really a problem at hand.

The suggestions as listed in the source story on the KTVN TV news site is also worth reviewing. Don’t do stupid things, including swallowing PSA’s and rationalizations whole.

Apple, 20 years ago

In 1998:

For $1,299, you came home with a 233MHz PowerPC G3 processor, 32MB of RAM, a 4GB hard drive, a 15-inch built-in monitor, and stereo speakers—all in an amazingly stylish case.

8 ways the iMac changed computing By Benj Edwards (first published in 2008) — “Apple’s most iconic desktop computer.” Popularizing the I’net, USB, floppy disk demise, and a ‘left coast’ industrial design with special appeal to the academia and the elite communities.

Twenty years on, the little box attached to the TV as a media center has nearly 10 times the clock speed, 100 times the RAM, 1000 times the mass storage, 3 – 5 times the screen size (widescreen, even), and one tenth the cost.

Python date and time

Trying to display, store, and calculate date and time values can be a significant challenge. This is why there are 6 Python datetime libraries by Lacey Williams Henschel — “There are a host of libraries that make it simpler to test, convert, and read date and time information in Python.”

“beyond converting strings to more useful Python objects with ease, there are a whole host of libraries with helpful methods and tools that can make it easier to manage testing with time, convert time to different time zones, relay time information in human-readable formats, and more. If this is your first foray into dates and times in Python, take a break and read How to work with dates and time with Python. To understand why dealing with dates and times in programming is hard, read Falsehoods programmers believe about time.

Now the problem is that of shopping for the best solution for your needs. That can be tricky, too.

Sense and Control: so many options

OK. got the Sonoff stuff going OEM. Now for the next step. I’m looking for two major features. (1) FOSS and (2) local without dependencies. Complexity is another factor as I’d rather the component count be in hardware rather than software. It’d also be nice if it was possible to get into customization and modification without needing a major development environment. VSCode and PlatformIO is about the limit for development.

The structure of the forest needs to be kept in mind as the entire ecosystem has to mesh and work together. At the device level there is the firmware. That can be OEM for purpose built devices or it can be ESPeasy, ESPurna, Tasmota or whatever. These may be stand alone but most systems depend upon a message broker often handling MQTT. Then there’s the decision and computation section to gather status and sensor information and send out control messages. Node Red shines big on that. Finally, there’s the User Interface. It can get complicated.

9 Home Automation Open-Source Platforms for Your projects provides an insight into just how many options are out there and gives you an idea of why a decision can be difficult. 6 open source home automation tools by Jason Baker — “Build a smarter home with these open source software solutions.” cites a few more packages and a few more issues.

OpenHab vs Home Assistant vs Domoticz – What fits you best? by David C hits another point. ” in this post we will focus on the three biggest communities. A big community translates into more ideas and more people sharing their knowledge with you.”

Home Assistant seems to be a mover and shaker right now. It is a Python 3 app and the developer has started the move to asyncio as in Python 3.4. It includes an MQTT broker. It’s UI is web based so there is no need for a special app. There are some leads to its use with micropython but that needs more research about what it’d take to get an ESP8266 device as a client with micropython rather than the more common prebuilt FOSS firmware.

When comparing these web based interfaces with ‘big’ apps such as Node-Red or the Jupyter Notebook, the impression is that a good web UI is a major Javascript development effort and the Internet of Things people have their focus elsewhere. That means the application sector is still feeling its way and getting standards and methods ironed out.