The Olson TZ (Time Zone) Database and Copyright…

They must have misread their stars! Astrolabe, Inc., who sells astrology software, acquired the copyright to “The American Atlas” by Thomas G. Shanks and then naively decided to sue the people who maintain the standard time zone database used in software worldwide. The Daily Parker promptly provided a great write-up in October, 2011 where David asked five questions:

  1. Is data about when time zone rules changed throughout history protected under copyright?
  2. If so, who owns it?
  3. If someone owns it, is the Olson database a derivative work under copyright law?
  4. If the Olson database does, in fact, derive from the work in question, is it a fair use?
  5. Just how stupid are these astrologists, anyway?

It’s useful to recall that government laws control time zone rules throughout the world. In the United States where the suit was filed, laws cannot be copyrighted nor can facts. That means the answer to question 1 is no, because it asks about facts (referred to as data). The actual text of the law(s) controlling time zone rules might have been copyrighted by the government that wrote them, but the facts themselves cannot be copyrighted. Since the answer to question 1 is no, the rest of the questions are rendered moot. Q.E.D.


S.H.I.E.L.D’s Helicarrier Could Lift-off Using Today’s Technology

S.H.I.E.L.D Helicarrier from The Avengers movie

Immediately after watching The Avengers movie (on opening day; and yes, it’s been quite a while), I set off, tongue firmly in cheek, to reality-check S.H.I.E.L.D’s Helicarrier. Professor Allain’s Wired blog “Could the S.H.I.E.L.D Helicarrier Fly?” arrives at a different conclusion than I did, so I thought it’s finally time to write up my alternate assessment.

Like the professor, I began by looking into Nimitz class aircraft carriers. Built using HSLA-100 steel, those 333 meter long carriers displace about 100,000 long tons. S.H.I.E.L.D, with flight as a design goal, would clearly upgrade to titanium, employ aircraft construction techniques, and use other advanced methods to lighten their 450 m Helicarrier by about half to 55,000 metric tons (t).

Next, could real fans fit in the space allocated and still generate enough thrust to lift 55 kt? Using the Harriers Alpha Jets on deck as measuring sticks shows that each of the four fans is 51 m in diameter giving a total rotor area of 8,200 m². The Helicarrier name invites comparison with helicopters, so I initially checked its fans against the remarkable Russian Mi-26 heavy-lift helicopter. The Mi-26′ has a maximum takeoff weight of 56 t using a rotor 32 m across to provide a lift/area ratio of 0.07 t/m². That herculean helicopter’s lift/area ratio provides only 1% of what S.H.I.E.L.D needs to fly. Helicopter rotors are out.

Fortunately, engineers have already done better, much better; the Rolls-Royce LiftSystem in the F-35B produces far higher lift/area ratios. For instance, the front LiftFan generates 20,000 lb of lift from a 127 cm (50 in.) fan and the whole system generates 19 t (41,900 lb) of lift from 2.51 m² of duct area (LiftFan, jet exhaust, and roll-posts). Its 7.56 t/m² ratio leaps two orders of magnitude past the Mi-26 and provides plenty of lift-off thrust for S.H.I.E.L.D’s headquarters. To sustain a single rotor failure, the Helicarrier engineers must have improved on Rolls-Royce by at least 14% to 8.61 t/m² or more. Nonetheless, the Helicarrier appears to fly within the laws of physics here.

Spinning those fans requires an enormous amount of power and generating it presents an even bigger engineering problem, but it hovers (barely) within the realm of possibility. The F35-B’s thrust ratio (55,000 shp delivering 41,900 lb thrust) implies the Helicarrier carries engine(s) capable of 157 million horsepower (shp) or ~117 gigawatts output (that’s more power than all of the nuclear power plants in the USA combined). Any power source would need to be scaled up, but allocating 20% of the carrier’s gross tonnage to the power plant sets the minimum power density at 10.8 kW/kg; for comparison, here’s a quick rundown of some real-world power densities:

  • A Pratt & Whitney F135 jet turbine in the F35B produces 38 kW/kg
  • The RS-25D Space Shuttle Main Engine delivers the highest power to weight ratio available today at 1445 kW/kg
  • For something closer to home, the LS9 supercharged V8 in a Corvette C6 ZR1 produces 638 HP and weighs 530 lb (dry) for a power to weight ratio of 0.9 kW/kg
  • The Indy Car Series 2012- engine weighs just 112.5 kg (248 lb) and puts out 522 kW (700 HP) 4.46 kW/kg or 5× the specific power of a Corvette but just half of what’s needed
  • A Nimitz A4W nuclear reactor weighs a lot more but at least it contains enough fuel for two decades; it generates 0.05 kW/kg with older, 18% efficienct steam turbines
  • The Los Alamos Heat Pipe reactor (alpha of 0.43) combined with 40%+ efficiency turbines raises its specific power to 0.8 kW/kg

Unlike the Nimitz aircraft carrier, nuclear reactors, even lightweight research reactors, won’t work. S.H.I.E.L.D would need around 530 A4W reactors to generate 117 GW and those would weigh over 2 million metric tons; that wouldn’t just ground the Helicarrier, it would sink it!

Shuttle main engines would weigh 81 t or 0.15% of the total. Using the rest of the weight allocation for cryogenic fuel provides 2 hours of flight time in a tank 111 m long and 11 m in diameter.

Turbines have high enough specific power but need to be scaled up a lot; just ganging together 3,000 P&W F135 turbines would be an engineering and maintenance nightmare! Real-world engines have high enough specific power for the Helicarrier, but scaling them up would be incredibly difficult.

For in-world consistency, I also had to consider Tony Stark’s imaginary arc reactors. His Mark III could generate 3 gigawatts (3×109 watts) and the Mark IV upgrade quadrupled that to 12 gigawatts (12×109 watts). Stark could easily pickup either version by hand and so I’ll assume a maximum weight of 50 kg. That’s 240,000 kW/kg! and a specific power 1,600 times greater than the Shuttle turbopump! Using an exotic power source like that obviates the need for anything fancy; just scale up a standard AC induction motor and watch it fly!

Genetically Engineered Crops and the Farmers Who Don’t Want Them

Q: What’s the difference between patented plants and other patented things?
A: The plants can make copies of the “patented” invention on their own without help from anyone.
This is a fundamental distinction that the courts have apparently overlooked.  The crucial difference between plants and other inventions is the fact that it doesn’t require any human action to replicate the patented invention. The plant, on its own,  will copy the covered invention as it goes about its natural life. If Monsanto wants to sue someone, sue the plant; after all, it was the life-form that exercised Monsanto’s patent.

The courts should recognize that when a farmer takes no action (the copy of the patented item was made by a plant),  then the farmer is in no way at fault for winding up with a patented item on their land.  Like I said, Monsanto should sue the plant.

Plants propagate; it’s a fundamental requirement for life, and if a plant with patented genes propagates on its own, then there cannot be a finding of patent infringement.  If there is, then the lawyers and judges have lost touch with reality;  go out and garden, then come back and judge again.

If a plant “inventor” really wanted to prevent Mother Nature from going about her business and making copies, then the inventor can engineer sterility into their plants along with whatever other traits they’re trying to enhance.  Otherwise, the plants themselves, without any help from us, will go about their business and replicate across the landscape.

Election 2012 Results for Utah Congressional District 4, Jim Matheson (D) wins by 768 votes over Mia Love (R)

Summary of Official Election Results for Utah Congressional District 4 Election, Jim Matheson (D) v. Mia Love (R)

Jim Matheson (D) remains part of Utah’s congressional delegation after winning by the slimmest of margins in Utah’s new District 4 against Mia Love (R).  Only 768 votes, or 0.31% separated him from Ms. Love.

FiveThirtyEight Blog Correctly Predicts 32 of 33 Senate Races

Nate Silver’s FiveThirtyEight blog correctly predicted the outcome of the presidential election in all 50 states and correctly called 32 of 33 senate races.  The one missed call in Montana was probably due the changing demographics that Micah Cohen wrote about earlier.

Improve VR Resolution Using Subpixel Rendering without Color Filters in Periphery

Visual Field of the Naked Eye, section 3.1 of Howlett, SID 1992.

Wide angle virtual reality (VR) displays need to wrap around up to 280° horizontally and  120° veritically to cover the human visual field¹;  within that area, eye motion can swivel the fovea over a circular area approximately 90° horizontally and vertically. That’s a lot of screen real estate! For comparison, THX recommends sitting just 6.5 feet (2m) from your new 65-inch HDTV but that still only fills 40° of view.

VR head mounted displays (HMDs) typically use lenses to magnify the screen so that it fills up more of our visual field. At high magnification though, the pixels get very large and image quality fades. A standard way to improve quality works with our eyes’ natural limits; the farther things are from the center of vision, the less clearly we see them.  Fisheye lens magnifiers work well with this limitation; they stretch the center part of the image less where we see better and magnify the outside areas more where we don’t see as well.

Another way to get more quality out of the image is to work with another limit of our peripheral vision.  Outside of the foveal sweep (aka the 90° direct field where we see sharply) our eyes do not perceive color.  Our brains keep track of color for us in the periphery, but our eyes don’t actually see that color; it’s literally all in our head. Wide angle VR display systems, therefore, can use sub-pixel rendering without applying a low-pass color filter; chromatic aliasing will not be visible for pixel triads in the periphery; this triples horizontal resolution outside of the foveal area for standard LCD stripe arrays.

Sub-pixel rendering without color filtering outside of the direct field can be used either to push more pixels into the direct field or to extend the peripheral field.  HMDs using “large expanse, extra perspective” (LEEP) optics, for example, can increase the fisheye magnification on the edges of the display and further improve the projected visual field. The constant k can be increased from the typical LEEP value of 0.18 to even higher levels of magnification.

LEEP optical compression. r = F (Θ – .18 Θ³) ≈ F sin Θ

If the HMD designer has input into the LCD design, additional resolution improvements can be incorporated by specifying a unique LCD color filter arrangement.  In the direct field portion of the LCD viewable by the fovea, individual sub-pixels should be colored in a Bayer pattern that better  mimics the physiology of the human eye.  Outside of the direct field, the LCD color filters should be eliminated altogether to improve the range of brightness and simplify sub-pixel rendering.

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Mobile view fixed for Wikipedia

I suggested this quick javascript fix for Wikipedia’s recent, and highly annoying, tendency to send my iPhone’s web browser to the Desktop version of pages.

jQuery(document).ready( function($) {
   // Put an onClick handler on the Mobile View link to unset the stopMobileRedirects cookie
       document.cookie = "stopMobileRedirect=false; expires=Sun, 01-Jan-2012 00:00:00 GMT; "
                    + "path=/;";

and today TheDJ and added it as a stopgap fix for everyone on Wikipedia!  Thank you!

Digital vs. Analog Photography

Film still has much higher resolution, a wider color gamut, and greater dynamic range than digital sensors; however, the convenience, instant feedback, and cost savings offered by digital photos and video will eventually confine analog film to niche uses. Today’s (2012) consumer level digital resolutions already capture images that exceed most people’s visual acuity for small formats (e.g. Apple’s “Retina” displays, 5″x7″ prints), but feature movies are still shot using 35-mm film to safely scale to large theater screens.

Ken Rockwell’s sage take on analog vs. digital in 2002 remains true today:

Convenience has always won out over ultimate quality throughout the history of photography. Huge home-made wet glass plates led to store-bought dry plates which led to 8 x 10″ sheet film which led to 4 x 5″ sheet film which led to 2-1/4″ roll film which led to 35mm which led to digital. As the years roll on the ultimate quality obtained in each smaller medium drops, while the average results obtained by everyone climbs. In 1860 only a few skilled artisans like my great-great-great grandfather in Scotland could coax any sort of an image at all from a plate camera while normal people couldn’t even take photos at all. In 1940 normal people got fuzzy snaps from their Brownies and flashbulbs while artists got incredible results on 8 x 10″ film. Today artists still mess with 4 x 5″ cameras and normal people are getting the best photos they ever have on 3 MP digital cameras printed at the local photo lab.

Most of the “digital vs. film” essays on the internet actually compare digitized scans of film against directly captured digital images and have the implicit goal of justifying a professional photographer’s expensive digital camera purchase. Unfortunately, the scanner usually limits resolution on the film side but rarely receives reviewer attention!

When critiquing articles, watch for comparisons that use a microscope to examine the film and look for discussions about the overall workflows’ impact on each imaging system. Only recently has lens MTF testing and discussion been revived for digital photography; film buffs in the 70’s and 80’s regularly read optical lab reports comparing lenses. This expansion of the conversation shows that high-end camera sensors have finally achieved resolutions that film had in the 70’s; the sensors have finally reached the point that lens quality can once again affect overall image quality. Despite Kodak’s financial difficulties, their research labs have continued improving film and digital still has ground to cover before it reaches the absolute resolutions available on film. 35-mm movies could deliver even higher resolution, if they needed to, by using larger formats; for instance, VistaVision exposes twice as much negative area (8-perf, horizontal frames exposed in the same way that a 35-mm still camera exposes them), but they don’t need to – other costs and limitations in the workflow are more important.

Color gamut, frame rate, and dynamic range remain problematic for digital imaging too. HDR algorithms and better sensors have only started addressing these problems. Panavision’s John Galt provides some good detail in “The Truth About 2K, 4K and The Future of Pixels” where he advocates for higher frame rates as the quickest way to improve perceived resolution.

My conclusion?  While film is technically superior, none of this really matters for me yet; the creative input of the photographer/director dominates the quality of the result. Even an iPhone, in the hands of an expert photographer, can outperform any camera in the hands of an amateur.  Instead of investing in increasingly higher resolution cameras or reverting to film, I’m heading to the library to improve the equipment between my ears!

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Why We Need Sex Ed Now

Everyone knows how to have sex; that knowledge is literally built into our DNA.  Sex ed just adds knowledge about practicing safe sex.  It lets us understand the complexities, how to avoid STDs, and gives us choices about when we want to have children.  After realizing that kids everywhere will become sexually active regardless of what they’re taught, the moral choice becomes teaching them safety.   More information to consider:

Reproductive Health Education

Created by: Public Health Degree


Relating Latitude and Longitude to Everyday Distances

I’m a cartography fan and Wikipedia’s geographic coordinates add another level of utility to articles.   Many of the latitude /longitude notations use six decimals of precision though which seemed like overkill.  When I recently added a {{coord}} template to an article,  I calculated how much distance each digit represents using imperial units (those familiar with metric units can look here).  Briefly, each tick of the sixth place changes position by about 8.5 cm or 4-⅜ inches (for latitude; longitude changes are even smaller and vary with the cosine of latitude).   Consumer GPS will only be accurate to about four decimals (or maybe five with WAAS).

The detailed calculation starts with the nautical mile to relate lat/lon coordinates to everyday distances. explains

“The length of a nautical mile is based on the circumference of the planet Earth. If you were to cut the Earth in half at the equator, you could pick up one of the halves and look at the equator as a circle. Then divide that circle, or arc, into 360 degrees and divide each degree into 60 minutes. A minute of arc on the planet Earth is 1 nautical mile. This unit of measurement is used by all nations for air and sea travel.”

Most of us don’t normally use nautical miles to pilot ships or airplanes and instead rely on smaller units like kilometers and miles.   For the conversion examples below, I’ll use the coordinates of the entrance to the USGS’ office in Menlo Park :

37° 27′ 22.86″ N,   122° 10′ 15.6714″ W
37.456350         , -122.17102

The notation degrees° minutes seconds  converts to decimal notation as shown here and then we can calculate typical distances corresponding with each position in the notation:

37 + 27/60 + 22.86/3600 = 37.456350
37°  27'     22.86"
 |    |       |  |
 |    |       |  +- 1/100 of an arcsecond = 1.0127 feet
 |    |       +---- One arcsecond    =  1 nautical mile / 60 = 101.27 feet
 |    +------------ One arcminute    =  1 nautical mile  = 1.15077945 statute miles
 +----------------- One (arc) degree = 60 nautical miles = 69 statute miles

In the decimal notation for this latitude, each position corresponds to the following north/south travel distances:

 | ||||||
 | |||||+- 0.00006 naut mi. = 0.3646 feet= 4.3748 or 4-3/8 inches=11.112 cm
 | ||||+-- 0.0006 naut. mi. = 3.646 feet =   1.1112 m
 | |||+--- 0.006 nautical mi= 36.46 feet =  11.112 m
 | ||+---- 0.06 nautical mi.= 364.6 feet = 111.12 m
 | |+----- 0.6 nautical mi. =  0.69 statute miles=   1.1112 km
 | +------ 6 nautical miles =  6.9 statute miles =  11.112 km
 +------- 60 nautical miles = 69 statute miles   = 111.12 km

Longitude lines. Traveling N/S along one changes your latitude.

(For reference, 1 nautical mile is defined as exactly 1.852 km and is about equal to 1.1508 statute miles.)

Traveling one arcdegree of latitude  north/south (by moving along a longitude line) represents the same distance anywhere on earth.

One degree of E/W travel requires different distance at different latitudes.

Traveling one arcdegree of longitude east/west (by moving along a latitude line),  however,  represents different distances depending on the cosine of the latitude’s degrees (north or south).  At higher latitudes, traveling one arcdegree east/west covers a smaller distance because circles of latitude are smaller at higher latitudes.

For example, in Caracas at 10 degrees north latitude, traveling one arcdegree along that latitude line represents east/west travel of:

1 arcdegree = 1 naut. mi. * cos(10 deg) = 0.985 nautical miles = 1.333 statute miles

but at 37.45635 degrees north, 1 arcdegree of east/west travel represents just:

1 arcdegree = 1 naut mi. * cos(37.45635 deg) = 0.7938 nautical miles = 0.9135 statute miles

These calculations are close to correct, however, the Earth is not quite a perfect sphere and so professional geodetic measurements use a mathematical model of those imperfections called a datum.  For more conversions, and pointers to the nuances introduced by geodetic systems, see .

Without access to professional surveying equipment and geodetic correction software, five decimals or 1/10 of an arc second, representing around 1m of accuracy, is about as accurate as a consumer GPS is likely to measure.

Go hiking and enjoy!