Van's Blog

Circuits As Proofs: Episode 1

2012-02-03T18:06:00.001-06:00

Electronic Circuits As Mathematical Proofs
Episode 1: Resistance is Futile

L. Van Warren MS CS, AE

Warren Design Vision
wdv.com

Friday, February 3, 2012

Introduction

I want you to forget for a moment that you are reading this as a consequence of digital technology. I want you to forget that the screen it was written on was imaged as ones and zeros running through a multitude of logic gates at high speed. I want you to forget the mountain of computational complexity we use everyday as our lofty perch.

A Lofty Perch

The Naked Truth

At various points in school and life you may have encountered a mathematical proof. For many they are tedious, boring and purposeless arguments that seem to serve no purpose but their own. I hope to convince you that without them, the digital revolution you now enjoy would not have happened. Further, I hope to give you a way of seeing proofs as never before, as everyday objects, familiar as bread and butter that you can consume to increase your understanding.

An Everyday Yet Monumental Example

When one enters a dark room, a common behavior is to flip on a light. A switch is thrown, and usually, but not always, the light turns on. Most of the time we proceed without giving this monumental event a second thought. But I tell you, that when and if that light came on, at that very moment, you proved something. You proved something mathematical. You proved something real. You proved that the light, and everything connected to it," worked". This is profound.

Not finished with your monumental act, you did something just as stupendous. When you left the room, the switch was thrown again. Usually, but not always, the light turned off.

If you flipped the switch AND the light came on, you proved that:

1) the switch "worked", it served as a human control between an OFF state and an ON state.

2) the wires from the switch to the light were connected and conducted electricity.

3) the light itself "worked", that its filament, tube, or junction converted electricity into light & heat.

4) that the power company, however complex, was intact and functioning.

If you flipped the switch and the light didn't turn on, you proved that one or more of the above statements was false, an equally majestic and complex treat of logical possibility.

Possible Explanations

It is possible, if you flipped the light switch, that something else happened.

It could be, that at the moment your hand touched the switch, you were abducted by magic aliens who connected your mind to an illusion machine that made you believe that the light turned on or off.

A Futile Resistance

This explanation violates common sense. It seems highly improbable. For Kurtnestetic incompleteness, we will consider such explanations unlikely at our current scale and existence. The magic aliens will be left in the care of our more mechanical readers, quantumly speaking

Situation as Circuit

Using this free download we sketch a circuit that represents our situation:

We have already committed several acts of abstraction, having:

· replaced real world objects by symbols in a graph

· chosen a voltage source to represent the power company

· chosen an LED to represent the light "bulb"

· sized the components so they didn't blow up

The resistor is along for the ride. It represents inefficiency and injustice in the system, such as "wires aren't perfect conductors" and poverty. We could have a separate resistor for each of the three original wires, but each time we add a resistor we must add a wire. This tendency of things to become more complex before they get simpler is called, "intermediate expression swell". Just how bloated things get is an interesting problem we will sidestep for now. Pushing all three resistors through the circuit and placing them side by side allows us to replace them all by a single resistor. All the losses are then treated as single equivalent loss, adding another act of abstraction to our efforts!

In doing so we invoked the rule:

"Resistors in Series Add Linearly"

R_equivalent= R₁ + R₂ … + R_N

Having transformed our little world into an "equivalent" circuit, we must define what "working" means. "Working" means Proven, Demonstrated, QED. We define "working" to mean that current is flowing around the loop in sufficient quantity and with sufficient potential to turn on the light. This is something we can measure in both worlds, simulated and real. We can measure voltage, we can measure current and we can measure whether the light is on or off. The single measurement of whether the light is on, abstracts away the need for two measurements, voltage and current. Aside: I always measure the voltage of household batteries before and after installation. It is incredibly informative. Measurement of current requires a meter alias ammeter to be placed in series with other circuit elements. Current flow is measured in units of Coulombs per second, or Amperes, much as water flow is measured in liters per second. It is represented by an arrow, labeled here "Meter de Courant" in a twisted French homage to the German American mathematician Richard Courant.

When the Hardware meets the Footwear

Two pictures conclude the example. One picture with the switch OFF, one with the switch ON. QED

OFF:

ON:

The astute reader will notice that the current is actually flowing more voluminously in one direction than the other. This happens too fast for us to see, so we think that the light is on, when it is actually pulsating. Because the light is an LED, it only shines when conducting current in the forward arrow direction. The back-flow happens because real diodes are naughty. They leak. Current flow is taken as positive when traveling from positive pole to negative pole of the source. The squiggly "current-limiting" resistor is sized to keep the LED from burning up like a comet and destroying our pretty little world in one puff of smoke, also known as the smoke test of a proof. The tiny fence on the arrow of the diode implies that current is not supposed to flow backwards even though it does. The act of proof, the light turning on when the switch is thrown, isn't affected by these details. They do however suggest deeper and more interesting issues are afoot.

Acknowledgements

This work is dedicated to parents, professors and friends that inspired it.
Illustrations are linked to their respective sources.

An Unexpected Circuit

2012-01-17T14:24:00.002-06:00

Introduction

I am going to write a short paper. It's going to be a fun paper because like you, I don't know how it is going to turn out. That should make it interesting for both of us. Today's topic is a little weird - it arose in a rather offhanded way. I wanted to write about it because it was like stumbling on buried treasure. I am going to write in the first person because it is easier for me to express myself that way.

The stupefying beauty of this is that if I don't succeed, it is incredibly possible that you may. If I happen to succeed, we both get a useful tool.

Background

The problem is this. I need 50 Volts of Direct Current in a lightweight and portable package. 50 VDC, not 6, 9, 12 or 24. It is okay if I have to use an outlet or extension cord but I need 50 VDC. One more thing - I need 600 Watts of it. Because power is voltage times current there will be 12 Amperes flowing through a wire somewhere. Oh and one last thing - I need this 50VDC with 600 Watts of power constantly available on the shortest of notice, say 1/20,000^th of a second and also in a sustained manner.

Please don't hang up when you read the following statement. Stay with me, it will be worth your while.

An electronic circuit is a mathematical proof.

A circuit is a proof. It is a proof in an ideal sense with idealized components. It is a proof in a real sense with real-world components. If a circuit works, then the system that it represents is true. Many mathematical and mechanical systems have equivalent circuits. We will revisit this powerful idea.

Possible Ingredients

Lead-Acid

50 VDC is a weird number to want. I could use four 12 Volt lead-acid batteries, settling out of court for 48 Volts, knowing full well Lead-acid batteries are not 12 Volts they are 12.63 Volts. I would settle for 50.52 VDC. Lead-acid batteries have two problems though, lead and acid. The first problem, Lead, is toxic, and more seriously, it is heavy. I don't like heavy things. I don't like lugging them around. The second problem, Acid, is also toxic, and more seriously, it burns stuff. I don't like burns and that yucky corrosion that forms on car batteries. So let's just drop lead-acid.

Lithium

I could use thirteen 3.7 Volt lithium-ion polymer batteries, settling for 48.1 Volts. Lithium batteries have two problems, cost and explosion. I don't like things that are too expensive for widespread distribution. Also they explode if they aren't charged carefully. I can handle a small battery exploding. That might even be fun. A battery with nearly a horsepower is not small and neither is its explosion. So strike lithium.

Step Down Transformer

I could use a 120 VAC step-down transformer to transform household current to the lower AC value and then rectify and filter that into 50 VDC.

Two problems emerge. Even ordinary 120 VAC step-down transformers are expensive and they are heavy. I already mentioned my dismay with lugging expensive stuff around. The astute reader will note that this is a lie. I mentioned my dismay with lugging heavy things around and my dismay with things that cost too much, but I did not mention my dismay with lugging expensive stuff around. In that subtle distinction, there is meaning. You might think I don't like lugging expensive stuff around because of theft, and that would be true, but that was not the point. The point was, I never said that, but if one wasn't careful, one might assume I said it, and leave the encounter thinking something was said that wasn't. The structure of this argument is similar to a circuit we will discuss in a moment.

Now since I have ruled out batteries or transformers I need what is called a switching power supply. Switching power supplies are cheap and abundant, but they have a problem that intimately affects their use. They create NOISE. Electrical noise. Electrical noise bothers me more than weight or cost.

MOSFET Modulation: Smooth, Quick, Efficient

What I would like to do is somehow sample 120 VAC in a smooth, quick, and efficient way. Then I can rectify it into 50 VDC and filter it according to standard practice. So now, we have an apparently simpler problem than 600 Watts of 50 VDC. I just need 600 Watts of 50 VAC. Ignore that because of efficiency more than 600 Watts is needed. Ignore that because of voltage regulation, a more than 50 VAC is needed. Settle for 600 Watts of 50 VAC. If it is made from 120 VAC smoothly, quickly and efficiently the rest is cake.

What if instead of brutal switching, which creates far-reaching wideband racket, we gently turn something on and turn something off in a smooth and efficient way?

This circuit does that… partially. The control gate of an N-Channel MOSFET is fed with a version
of the same signal we are trying to clamp to 50 VAC. I say, "clamp" because when the voltage goes over 50 VAC we don't want any part of it. We especially don't want to accept this higher voltage and in turn dissipate the excess energy as noise or heat.

We can exactly tailor how much of the positive going side of the 120 VAC makes it to the voltage probe by adjusting the values of R1 and R2. If they are equal, we get 50 VAC on the positive going side of the wave:

So just like that we are halfway done. The signal is about 50 VAC on the top. In the figure above, both the 120 VAC signal and the output signal are drawn.

We would like to do the same thing on the bottom, so let's start simple and build a circuit that just does the opposite of the first one. Maybe then, we can combine them to get what we want. A circuit might do the "opposite" is one that uses a P-Channel MOSFET, the "opposite" of an N-Channel MOSFET:

After trying some different configurations we run it and get what we want –the negative side of the 50 VAC is present:

Now perhaps we can combine the two that will clamp both sides of the waveform to 50 VAC.

Running the simulation, we obtain:

We have achieved our objective. A real circuit might have some additional parts for protection, but this shows that the configuration is valid.

What I did not show you was the search process that a reasonable person might have employed to come up with this configuration.

If you look closely at the schematics, you will notice that MOSFETS are not commutative.
With the gate in the middle, they can be put in forwards or backwards.

This gives rise to four possible circuits, since there are two MOSFETS in use, and only one circuit topology will produce ("prove") the correct waveform.

In addition, the MOSFETS need not live on the positive supply, they could also be placed on the bottom of the load, but because of symmetry, this would still prove the correct waveform:

So now, we have eight possible circuits of which two are equivalent and correct and six are incorrect.

Additionally we can swing one MOSFET around to be on top of the load and one on the bottom:

Which produces the following output:

Swinging the P MOSFET around instead of the N MOSFET produces a similar incorrect outcome. That makes 2 of 10 possible configurations correct.

We can increase that by 4 more configurations by pivoting each MOSFET in the swung around configurations, which also produce incorrect outcomes.

If I have counted correctly, 2 out of 14 configurations are correct. But now we are not doing circuit design. We are searching over a space of possible connection topologies for a topology that proves (produces) the waveform we sought. Each of the topologies proves something, but only two proved what we set out to prove.

Conclusion

We have succeeded! It was discovered that we can produce (prove) the desired waveform and discovered two topologies that were satisfactory. The circuits we have produced are equivalent to other systems that have similar algebraic or mechanical characteristics. These equivalent circuits and their topologies not only model the equivalent algebraic and mechanical forms, they model the search process we might employ to discover useful circuits along with its combinatorial growth.

Easter Egg

I mentioned above that "protective circuitry" was needed to take this synthetic design into a practical unit. It turns out that the MOSFET gates need their voltage clamped to around +/- 10 volts. So the working design looks like this. Twelve parts drawn from 5 types, not counting power cord, fuse and load. An ounce of material you can hide in your hand. Two MOSFETS and power diodes in the top section, all in T-220 cases on a heat sink to handle 12 amps. The “Logic” section on bottom, runs on 6 milliamps that turns on the MOSFETS in 7 microseconds. 576 Watts. $9.15 worth of parts, the front-end of a $600` power supply. Those savvy in the trade will notice that this is a smoother version of an H-Bridge circuit used to control motors, so they don't jerk as much when doing, "the robot".

The file with the component values is available for $9.95 if you send me an email at the address on the left. It uses TINA SPICE from TI.

Acknowledgements

Brian Beckman, private communication.

References

As hyperlinks throughout the text.

JFK and Water Quality

2011-11-22T13:02:00.000-06:00

Dear Pulaski County Planning Board -

On November 22 we remember the passing of John F. Kennedy agreat American president from the early sixties. Although media sensationalistssay bad things about him, I remember him from Profiles in Courage, PT-109, theApollo Moon Program and his saying, "Ask not what your country can do foryou, ask what you can do for your country". I became a "rocketscientist" as a result of his vision and worked at NASA-JPL for 10 years.Among other things I worked on the Mars Rover, atmospheric science spacecraftand the Earth from Space Image, which was bought by Keyhole, then Google andturned into Google Earth.

This same November 22 will also host a planning board voteof Pulaski County Planning Board. I have an admiration for the board becauseyou have gotten things done where other organizations of local government havebeen less effective. As a bicyclist I enjoy the Big Dam Bridge, the Two RiversBridge and most recently the Clinton Pedestrian Bridge as a result of yourefforts working hand in hand with others.

When my wife and I made the decision to come home toArkansas to raise our children, two of our main criteria were the clean air andclean water that we grew up with. Before we went to college and moved aroundthe country we had no idea how polluted the air and water were in other areasof the country. You could not drink the tap water and enjoy it safely the waywe had in Arkansas. Bottled water contained no fluoride which is good forteeth, and the bottles create huge amounts of plastic waste. It was just awful.

I have come to understand that our drinking water comes fromMaumelle, which is uniquely situated at the bottom of a natural drainage valleythat collects everything poured into it. Rainwater is percolated through layersof green forest and rock to be filtered naturally before appearing in the lake.

Sitting before your decision-making eyes is legislation thatif enacted promises to turn our pristine water supply into shoe polish!Unbridled development adjacent to the Maumelle watershed will urbanize thenatural filtration system that keeps the water pure. Once released thisdevelopment will continue to encroach until our water is contaminated by sewagerunoff, weed killers, broken pipes, industrialization, petroleum wasteproducts, garbage and most importantly phosphates. As phosphates from sewageand yards runs into the lake, there will be profound and irreversible changesin the biology of the lake. Algae blooms will form like they do in all pollutedlakes, and the water will become rancid and dirty. Not a fitting legacy toleave to our children and grandchildren. They will leave us for greenerpastures, only to find that the entire country has become polluted. They willcurse us every time they take a breath of polluted air, or a drink of pollutedwater asking, why we, the stewards of our country, couldn't leave them a betterdestination.

Please remove the village density option from the LIdistrict, prevent forest clear cuts and require a minimum of 30% undisturbedarea.

All the best,

- Van

L. VanWarren MS CS, AE

CC: Don Castleberry, Chris Baker, Sandra Brown, Gary Boyle, Lawrence Dupree, Allen Engstrom, Ron Copeland, Randall Neill, Bill Rath, Ray Vogelpohl

Sent: Thu Nov 17 13:10:28 CST 2011

Scaling Laws for Fractal Antennas

2011-11-16T16:43:00.004-06:00

I was doing some simulations of fractal antennas recently and a friend said, "I'm talking about the postage sized antenna for 160 meters."

The statement intrigued me for several reasons:
1) Perhaps fractal antennas scale differently because of fractal dimension?
2) How small would such an REALLY antenna be?
3) How does fractal dimension affect the performance of the antenna?

Dr. Nathan Cohen (W1YW) owns the patent on fractal antennas. If you really like fractal antennas too bad. You cannot build them and sell them without paying a fee that is determined by whatever he feels like charging. Getting a patent on a topic like "fractal" and "antenna" is kind of like getting a patent on "software" and "engineering". At first it sounds cute and general, but in the end it is the most obstructionist, monopolistic and selfish thing one can possibly do.

Nonetheless, one can analyse fractal antennas without limit, so we can answer the questions without worrying about paying usury.

The Analysis Tools

The questions were answered via extensive analysis. Analysis was performed using 4NEC2 an excellent adaption by Arie Voors of the Numerical Electromagnetics Code by J, Burke and A. Poggio. These links will open in a new window if you would like to check them out. Arie Voors has provided his work free to the community, so there are still unselfish people left in the world. The Minkowski Antenna configuration used in this study is excellently and freely described here by Camps-Raga and Islam at the University of Missouri, Columbia. The 'C' program minkowski.c, the bash script, doit.bash, and the parameter file, tail.txt used to generate the antenna examples are freely included at the bottom of this technical note.

The Free Answers to the Questions

1) A fractal antenna of a given configuration and dimension scales
linearly in wavelength just like all antennas do.
2) A Minkowski fractal antenna for 160 meters would be 36 feet wide.
It would have a gain of -19.3 dB relative to an isotropic radiator.
3) Increasing fractal dimension decreases antenna size BUT
gain drops much faster than size.

Other Free Facts

1) A fourfold reduction in antenna size is accompanied by a gain reduction of 21.3 dB so there is a severe penalty for size reduction. Gain drops like a stone is a more fitting characterization! My hypothesis is that as fractal dimension increases, the antenna starts to look more like a mirror than an absorber of electromagnetic energy.
2) A level 0 Minkowski fractal is a square loop antenna! The makes a nice basis for comparison.
3) Minkowski doesn't charge a royalty for his fractal even though he was a great mathematician and contemporary of David Hilbert.

Analysis Details

'C' Code Used to Generate the Minkowski Fractal Antennas

The 'C' code was written entirely by the author using the principle of segmenting a single line and offsetting the middle segment by a distance h. The code was compiled using the cc compiler from the fantastic and free cygwin running on top of Windows XP on a dual core Intel processor and ASUS motherboard from newegg.com. If you have never had the pleasure of building your own computer from off the shelf components I urge you to do so. You will save a ton of money and get a computer more suited to your needs. Anyway, here is the 'C' code:

------- cut here -------
// Minkowski fractal antenna generator by van at wdv dot com

#include
#define SOUTH 1
#define EAST 2
#define NORTH 3
#define WEST 4
#define MAX(a,b) ((a)>(b)?a:b)

int maxLevel = 1;

void edge(double xA, double yA, double xF, double yF, int type, int level)
{
double W = 1.0 / 3.0;
double H = 1.0 / 3.2;
double L, w, h;
double xB, yB;
double xC, yC;
double xD, yD;
double xE, yE;

if(level >= maxLevel)
{
printf("1\t0\t%9.4f\t%9.4f\t0\t%9.4f\t%9.4f\t1.e-4\n",
xA, yA + 1, xF, yF + 1);
}
else
{
if(type == SOUTH)
{
L = xF - xA; w = L * W; h = L * H;

xB = xA + w; yB = yA + 0;
xC = xA + w; yC = yA + h;
xD = xF - w; yD = yA + h;
xE = xF - w; yE = yA + 0;

edge(xA, yA, xB, yB, SOUTH, level + 1);
edge(xB, yB, xC, yC, WEST, level + 1);
edge(xC, yC, xD, yD, SOUTH, level + 1);
edge(xD, yD, xE, yE, EAST, level + 1);
edge(xE, yE, xF, yF, SOUTH, level + 1);
}
else if(type == EAST)
{
L = yF - yA; w = L * W; h = L * H;

xB = xA + 0; yB = yA + w;
xC = xA - h; yC = yA + w;
xD = xA - h; yD = yF - w;
xE = xA + 0; yE = yF - w;

edge(xA, yA, xB, yB, EAST, level + 1);
edge(xB, yB, xC, yC, NORTH, level + 1);
edge(xC, yC, xD, yD, EAST, level + 1);
edge(xD, yD, xE, yE, SOUTH, level + 1);
edge(xE, yE, xF, yF, EAST, level + 1);
}

else if(type == NORTH)

{

L = xA - xF; w = L * W; h = L * H;

xB = xA - w; yB = yA + 0;

xC = xA - w; yC = yA - h;

xD = xF + w; yD = yA - h;

xE = xF + w; yE = yA + 0;

edge(xA, yA, xB, yB, NORTH, level + 1);

edge(xB, yB, xC, yC, EAST, level + 1);

edge(xC, yC, xD, yD, NORTH, level + 1);

edge(xD, yD, xE, yE, WEST, level + 1);

edge(xE, yE, xF, yF, NORTH, level + 1);

}

else if(type == WEST)

{

L = yA - yF; w = L * W; h = L * H;

xB = xA - 0; yB = yA - w;

xC = xA + h; yC = yA - w;

xD = xA + h; yD = yF + w;

xE = xA - 0; yE = yF + w;

edge(xA, yA, xB, yB, WEST, level + 1);

edge(xB, yB, xC, yC, SOUTH, level + 1);

edge(xC, yC, xD, yD, WEST, level + 1);

edge(xD, yD, xE, yE, NORTH, level + 1);

edge(xE, yE, xF, yF, WEST, level + 1);

}

main(int argc, char **argv)

{

if(argc > 1) maxLevel = atoi(argv[1]);

edge( 0, 0, 16, 0, SOUTH, 0);

edge(16, 0, 16, 16, EAST, 0);

edge(16, 16, 0, 16, NORTH, 0);

edge( 0, 16, 0, 0, WEST, 0);

}

Bash Script Used to Generate the Minkowski Fractal Antennas

The 'C' program above, though somewhat minimal, produces extra copies of the segments during the recursion. The output lines are only part of the "card entry" fragments necessary for 4NEC2. To get the output file into a form usable by 4NEC2 the following script was run:

$doit.bash 2

which produces a level 2 Minkowski fractal antenna.

------- cut here --------------

#!/bin/bash
minkowski.exe $1 | sort -u | nl | sed -e 's/ //g' | sed -e 's/^/GW\t/' > head.txt
cat head.txt | wc -l > /tmp/tmp.txt
lineCount=`cat /tmp/tmp.txt`
echo $lineCount
sedCommand="s/NSEG/$lineCount/"
echo $sedCommand
cat tail.txt | sed -e "$sedCommand" > foo.txt
cat head.txt foo.txt > MI3ALVW.nec
u2d MI3ALVW.nec

~

The Last File

The last file "tail.txt" is used by the bash script to provide analysis parameters for 4NEC2. It looks like this:

------- cut here ----------

GE 0
EK
LD 5 0 0 0 5.74713e7 0
EX 6 NSEG 1 0 1 0
GN 2 0 0 0 13 0.005
FR 0 1 0 0 1.8 0

Testing a cool posting style excerpted from Matt Might

2011-07-31T22:52:00.027-05:00

In his excellent blog on the Y-combinator, Matt Might - a professor at my alma mater, the University of Utah - uses a technique for placing executable Javascript code in the flow of his document.
Right now I am pasting his code into the html editor of my Google blogger to see if I can reproduce the trick he uses. The part that follows is in double quotes, as it is Matt's work:

Open Double Quote

The following example expresses the factorial function without using recursion:

// A "functional" is just a function that takes// another function as input.  // The Y combinator finds the fixed point// of the "functional" passed in as an argument.// Thus, the Y combinator satisfies the property://     Y(F) = F(Y(F))// Note that Y does not reference itself:var Y = function (F) {  return (function (x)  {   return F(function (y)   {    return (x(x))(y);   });  })(function (x)  {   return F(function (y)   {    return (x(x))(y);   });  }); };// (In fact, all functions above are anonymous!)// FactGen is the functional whose fixed point is// factorial.// That is, if you pass the factorial function to// FactGen, you get back the factorial function.// Since the Y combinator returns the fixed point// of a functional, applying the Y combinator to// FactGen returns the factorial function!// Note that FactGen does not reference itself:var FactGen = function (fact) {  return (function (n)  {   return ((n == 0) ? 1 : (n * fact(n - 1)));  }); }; // (In fact, all functions above are anonymous!)  // FactGen is the functional whose fixed point is// factorial.  // That is, if you pass the factorial function to// FactGen, you get back the factorial function. // Since the Y combinator returns the fixed point// of a functional, applying the Y combinator to// FactGen returns the factorial function! // Note that FactGen does not reference itself:  var FactGen = function (fact) { return (function(n) {  return ((n == 0) ? 1 : (n*fact(n-1))) ; });} ;   document.getElementById("result1").innerHTML  = (Y(FactGen))(6) ;

[result1]

Take a close look at the definition of Y. It uses only three kinds of expression: anonymous functions, variablereference and function application.

Close Double Quote

Back to my words: Note that even though this is a blog, the html is still functional and the Javascript program executes when the "Evaluate" button is pressed. So handy for making those subtle programming points!

If you right click this page and choose, "View Source", You can see the embedding of the code between lines 456 and 524. A short preamble and "postamble" are all that are required. Thanks Matt!

Footnotes:
Attempts to paste commented html tags were futile as they were evaluated. Attempts to color the code red didn't work either.

Regarding "Informational Derivation of Quantum Theory" by Chiribella, et.al.

2011-07-20T18:16:00.001-05:00

Regarding "Informational derivation of quantum theory", "PHYSICAL REVIEW A 84, 012311 (2011)", Chiribella

I was provoked to cast Information Compression as an Iterated Function

So given a string S, of length L, find an iterated function F, that produces a new string S’ of length L’ where L’ < L.
One might also require an iterated function G = F-1 that takes S’ and produces S.
If such a G exists, then F would be called a lossless or invertible iterated compression function.

S = "The rain in Spain stays mainly in the plain."
L = 45

F1 = { s/ain/1/g }

S1 = "The r1 in Sp1 stays m1ly in the pl1."
L1 = 37

F2 = { s/he/2/g }

S2 = "T2 r1 in Sp1 stays m1ly in t2 pl1."
L2 = 35

F() = F1(F2())
S' = F(S)
L' < L since 35 < 45

G1 = { s/1/ain/g }

G2 = { s/2/he/g }

G = G1(G2())
S = G(S')

F is invertible, iterated and compresses.

Sidebar 1: F can be packaged with S:

Sp = F + S = /ain/1/he/2/"The rain in Spain stays mainly in the plain."

Next Step: Find an Iterated Function that performs Information Expansion

So given a string S, of length L, find an iterated function F, that produces a new string S’ of length L’ where L’ > L.
One might also require an iterated function G = F-1 that takes S’ and produces S.
If such a G exists, then F would be called a lossless or invertible iterated expansion function.

S = "The rain in Spain stays mainly in the plain."
L = 45

F = { s/[a-zA-Z]/[%3d]/ }

S1 = "084he rain in Spain stays mainly in the plain."
L1 = 47

S2 = "084104e rain in Spain stays mainly in the plain.
L2 = 49

S' = "0841041010321140971051100321051100320831120971051100
3211511609712111503210909710511010812103210511003211
6104101032112108097105110046010"

L' > L since 135 > 45

G = { s/[%3d]/[a-zA-Z]/ }
S = G(S')

F is invertible, iterated and expands.

Sidebar 1: F can be packaged with S:

Sp = F + S = /[a-zA-Z]/[%3d]/"The rain in Spain stays mainly in the plain."

In this context we call F, the "transcription apparatus".

Next Step: Show that the cost of mutagenesis is higher in the compressed case.

This is trivial and will be left as an exercise to the reader.

Source for F in Expansion Section:

#include

/* convert any number to itself and any letter to a number */
/* hint add a comma to each phrase and watch intronic explosion */
/* hint remove the commas and watch loss of reading frame */
/* hint add triplets and watch need for reading frame */

int isNumber(int c)
{
return ( ('0' <= c) && (c <= '9') );
}

void echo(int c)
{
printf("%c", c);
}

void number(int c)
{
printf("%03d", c);
}

main()
{
int i;
int c;

for(i = 0; (c = getchar()) != EOF; i++ )
{
if( isNumber(c) )
{
echo(c);
}
else
{
number(c);
break;
}
}

for(; (c = getchar()) != EOF;)
{
echo(c);
}
}

The Impedance of Free Space

2011-06-08T12:58:00.001-05:00

The impedance of free space is ~120π, or about 377 Ohms.

What does that mean?
Does nature oppose the propagation of light?
If it does, would we even see star light?
Or is this a fee that, once paid, admits to a photon the right to propagate until it collides with something else?

It turns out that the "impedance" of free space is really just a ratio of strengths.

It is the ratio of the electric field strength, to the magnetic field strength.

Its numerical values are just an artifact of the definition of the ampere and the meter.

It might be interesting to work backwards and say that the impedance of free space is one and see how that could lead to a useful set of units for Maxwell's equations.

Cancer via Sunlight-Activated Viruses

2011-03-20T18:26:00.001-05:00

When the weather gets sunny we slather upon ourselves various lotions, potions and screens whose stated purpose is to protect us from ultraviolet light. The reason offered for this sloppy ritual is that we are protecting our DNA from damage caused by UV rays. In this note, I want to highlight a coincident mechanism. That mechanism is viral activation via ultraviolet light. In other words, we wear sunscreen to prevent the activation of endogenous viruses already happily inhabiting our DNA.This DNA can be acquired from past insult or as a result of ongoing viral infection!

I include this picture because I can. It promotes a product by Banana Boat who gave loads of free sunscreen to our 100 mile bike ride - sunscreen I enjoyed until it was confiscated by a nervous TSA screener, certain that it was a liquid grenade. Both life-changing facts that any self-respecting scientific journal would omit. But I digress.

- source

Point One: There are viruses, that, instead of attacking people, attack bacteria. The playing field is closer to level. One famous baceteriophage is called "lambda", not to be confused with the "lambda" meaning wavelength of light, coincidentally a useful mnemonic.

Theses viral "phages" attack via a Trojan horse exploit wherein the virus gets manages to stow itself away in the bacteria's DNA where it lies quietly waiting for a sunny day. Then on that special sunny day lambda, through a marvelous ballet, it activates. Emerging from hibernation, it is assembled, courtesy of the hosts transcription machinery, which is tricked into making numerous unwelcome copies of this cosmic hitchhiker, at the expense of its host germ. The unfortunate germ promptly serves the community by exploding and launching an army of viral phage clones.

At the scale of viruses, light waves are big and you can't use something bigger than a thing to make an image of a thing without bludgeoning both the thing and image badly. Green light, where our eyes are most sensitive is 550 nanometers in wavelength. As the figures shows, lambda is 55 nanometers wide. So 10 virus particles fit in the width of one wavelength of light. Which one would you see? None of them... properly. So we sketch pictures of things that are actually wiggling furiously and quantum mechanically, and these pictures show some structure and some function, but not the true animated behavior of the viruses. Viruses are skinned and stuffed for taxidermy via electron microscopes and imaged with short wavelengths.

Point Two:
There is a certain transcription factor, a certain automotive part in the apparatus that enables DNA to be scanned and turned into messenger RNA. There are many such factors which must conspire and assemble to successfully read DNA, but the one to focus on here is BRCA1. The image below sketches the engine of transcription.

- source

This transcription factor, when mutated, causes cancer, particularly breast cancer, thus its name. But as you will see mutation is the least of BRCA1's problems. If you look at the gene and sort it by its functional and nonfunctional parts, it turns out to be heavily laden with DNA repeats - copies of viral litter and misspellings that serve no apparent purpose other than to change the length and possibly the timing of transcription of the cognate gene. Notice that BRCA1 is necessary for the reading of itself, a recursive sort of situation that is simply wonderful... unless something is broken. I am using BRCA1 as the poster child for the fact that our DNA is chock full of repeated sequences of ancient viral wreckage. Some of this wreckage is functional and some of it isn't. You don't really know till you go out on a sunny day. Here is a picture of BRCA1, when sorted, only the top few rows code for transcription factor. The rest is cosmic litter.

- source

The gene called BRCA1 actually contains instructions for four different proteins, IFP35, BRCA1, RHO7 and IFB35. These instructions are called exons. If you place your mouse on the image you can see these exons at the very top in the sorted version. The next region down with a regular pattern consists of noncoding DNA called ALU repeats. These make up 35% of the BRCA1 gene. These are the regions in the middle. The smeared appearance is due to deletion and point mutations that have occurred over the entire history of this gene.

Point Three:
This cosmic litter, the random interspersed repeats are ubiquitous throughout the genome. some of these repeats are viruses that, as in the bacterium, have stowed away in the genome. These viruses, activated by sunlight can make copies of themselves, and when those copies are integrated into tumor suppressor genes, or cell growth genes, or even in the Xerox transcription genes, the result can be cancer.

- source

Finally
Regrettably I am not an experimentalist, so I will have to leave to the labs of those larger than mine the task of putting this hypothesis to the test. In the interim... wear sunscreen!

Trustworthy Java Applets Without Costly Certificates

2011-03-08T00:49:00.011-06:00

Introduction
When you run a Java applet, the run time system looks for a file called java.policy, on your customer's system. This file specifies what rights Java will be granted at run time. If this file is not configured correctly your Java applet will not function properly and your customer will be frustrated. The only alternative to providing your customer a java.policy file is to buy a certificate that can cost over $500 per year. If your applet does not generate sufficient revenue to cover this, your voice is silenced along with your right to contribute. This also destroys the chance that your applet will be useful to someone a year from now, robbing you of future options as well.

So we would like to get useful applets running without permission problems while respecting the customer's right to security. We will accomplish this by establishing and maintaining a trust relationship with the customer as any supplier must do. In what follows the terms customer and user may be used interchangeably.

Applet Execution
Most applets are executed during development in interactive environments like NetBeans or Eclipse. For simplicity, an applet can be run in a browser, or as a standalone program, by you or your customer. Assuming Java is installed, an applet can be run in a browser simply by visiting a web page that hosts it. It can also be run in standalone mode by typing:

at a command prompt. Getting the right prompt is critical, otherwise hidden errors can disguise what Java is really doing. Getting the right prompt will be covered below. The term right prompt is a useful misnomer. It is really the environment behind the prompt that must be checked, but we want to make a complex thing simple, so we pretend it is a single character, keyword, or phrase, like mathematicians do.

Running appletviewer is useful for testing security fixes. Why? Because you can run it with test java.policy files like so:

Notice there is no space between the -J and the -D in the statement above.

A useful java.policy file for development and testing is:

Blanket permission is not safe for production settings. You can stop here, develop the most sophisticated applet you want, and then resume to deploy your applet. We will now cover four remaining issues to understand and solve Java applet security problems. These issues are:

Getting system properties such as ${user.home}
Getting the right prompt for Windows and Unix systems.
Testing an appropriate java.policy file.
Deploying a java.policy file.

1. Getting System Properties

Some users and most developers have several versions of Java installed. In this situation the value of key system properties can depend on what you are doing. Continuing our java.policy thread, we need to know the exact directory to which ${user.home} refers. To replace complex speculation with simple fact, we run the program PrintUserHome.java:

to produce the output:

Authors note:
In the text below, please assume that any word that starts with an upper case letter is a trademark held by their respective owners.

Many Java developers use Interactive Development Environments (IDE's) such as Netbeans or Eclipse. Compiling and running tiny programs in these can be a hassle. This hassle can be eliminated by running programs in Unix environments, like MacOS/Linux, or in cygwin, a wonderful Unix platform which sits atop Windows. In any of these a tiny Java program can be run without an IDE, without ant or make using the policyInstaller available at the end of this document. In the java.policy file above, we give the Java Runtime Environment (JRE) permission to read files from ${user.home}. This directory becomes the "sandbox" for those activities our grant permission directive allowed. Other key system properties can be listed using similar calls to those above. These are also enumerated in the policyInstaller:

2. Getting 'The Right Prompt'
We can inspect other key system properties by typing:

$ set | grep "JAVA|CLASSPATH"

On the same machine we can open a command "Window" and repeat using a variant of the same command:

$ set | grep "JAVA\|CLASSPATH"

Here we notice an important discrepancy, that the value of JAVA_HOME is different.
It is ...\jdk1.6.0_22 in the first case and ...\jdk1.6.0_10 in the other.

If we were to place an applet policy file in the wrong JAVA_HOME location, it would not work, and we might not know why. If that was done both the customer and the developer would be frustrated. Not good!

This can be fixed by editing the windows environment variables, which require a reboot of the system to take effect. To access these, right-click the mouse and select:
My Computer-->Properties-->Advanced-->Environment Variables.

Then examine the System variables.

In this case we would change the JDK version suffix from 10 to a 22 as shown and reboot.

When these two environments are consistent we have the 'right prompt'. More formal developments can be found at the references provided.

3. Testing an appropriate java.policy File

The blanket permission we granted above for testing and development is not appropriate for applet deployment. Instead we run the applet together with the java.policy file in the local directory granting the most restricted possible permissions until security exceptions no longer occur. As before this is done using appletviewer with the options shown below:

Each a time an exception occurs, we can add a line to the java.policy file that grants permission for that specific exception, using the text of the exception itself as a guide.

The java.policy file above restricts File I/O to the directory Java calls ${user.home}.

The wildcard character '*' says that any file or directory in ${user.home} may be read or written. One could add the keywords write,delete or execute to this permission directive. Additional keywords are separated by commas, i.e.: "read, write, execute", etc. The references titled "Appendix A..." below provides a complete description of all the possible permission directives. For example, in the applet that motivated this blog entry, the final java.policy file looked like this by the time it ran without exception.

After we have successfully tested the applet using a candidate java.policy file we are ready to deploy both the applet and policy files.

4. Deploying an java.policy File.

Local Deployment
We first deploy the java.policy file locally to the directory in which we were running the applet. . Then we test the applet again using applet viewer.

Now we have a compatible applet.html and java.policy combination. The applet.html can be deployed either as a proprietary custom solution for desktop use, or as a traditional web page for widespread use. We will cover the later case. Since a correct java.policy file is required for execution of many applets, the file itself, properly installed constitutes an informal key enabling the software to function. Note that whenever the user upgrades their version of Java, a new java.policy file must be deployed to the correct location.

There are two ways to deploy the java.policy file. One is to let the user download and install it themselves, but this requires expertise and patience some customers may not have (regrettably). Another way is to bundle the file in the policyInstaller below which the customer downloads and executes to install the java.policy file. It is good practice to inform the customer of the risks that installing the policy file may entail. This can be part of the EULA that the installer requires the customer to agree to, or placed on the web page from which the policy file is downloaded.

Location of the java.policy file.
For an applet to run on a user's machine the java.policy file must be installed in this location:

${user.home}\.java.policy

Policy Installer
A zip file containing the policyInstaller, source code, directory structure, and setup instructions for the IDE-less Java examples is available by sending $19.99 via PayPal to the author's email address. The zip file describes how to quickly and easily make a simple jar file and manifest for testing java.policy files and IDE-less java execution.

References:

2010-11-12T14:08:00.001-06:00

TEST

A Short Note On Complexity in Nature

2010-10-11T15:30:00.005-05:00

I was thinking about complexity this morning.

- image credit

When we zoom out from a given scene, we embrace more and more complexity. Although we cannot directly perceive this complexity, we can imagine it being there.

- image credit

As we zoom out we embrace more and more collections of matter and interrelationships between them. As we zoom back in, there is less stuff, and presumably fewer relationships.

- image credit

As we keep zooming in we get down to the level of organic molecules, which are made of atoms, which are made of elementary particles, which are perhaps made of strings:

- image credit

I was wondering if the universe was "programmed" like body plan is programmed via our genome. DNA is a base-four digital code that, when evaluated, defines the body plan of most organisms, except for RNA viruses.

These collections of particles were "smart enough" to sweep their orbits clean when they were the size of planets, condensing from accretion disks:

- image credit

So my thought is, "What if complexity increases as we zoom in? That is, the scale we live at is actually one of intermediate (apparent) complexity."

- image credit

If this is true, then the more we search for elementary particles at ever increasing energies, the more we will find.

- image credit

I am curious about this idea and if there is an encoding of universe body plan at the subatomic level.

- image credit

Design Patterns vs. Components in Software Resuse

2010-09-13T23:43:00.001-05:00

I have been pondering the dichotomy of Design Patterns vs. Reusable Software Components (RSC's). Are they they same thing, or are they opposites? RSC's are the integrated circuits of software while design patterns are reusable chunks of observable interactions that appear repeatedly. A design pattern is not an algorithm for performing some calculation. It is a higher level aggregation, often with less specificity. Thus design patterns are not themselves implementations of solutions to computational problems, or interaction scenarios. Similarity vs. Uniqueness is a controlling idea here.

- Agile Modeling

A key idea in clarifying this is to consider the difference between functional blocks of capability versus the interconnections between functional blocks. Another useful idea is that of process. Functional blocks, at any level of aggregation can be reduced to a single idea. One has inputs to the block that produce outputs from the block. Ensembles of functional blocks can always be replaced by a single equivalent functional block that abstracts away the internal complexity of the contents. Functional blocks make mathematical and algorithmic descriptions look like circuits. In fact, a software functional block can always be replaced by an equivalent piece of hardware and vica versa. This fact has not yet been fully exploited in the current software revolution, otherwise you could buy Microsoft Word on a chip.

Imagine taking the 23 design patterns, overlaying them on each other in the 253 possible ways and asking what are the similarities and differences between them and their subsets?

These differences are largely the interconnects that glue together portions of the patterns, as opposed to the blocks of UML themselves. UML is a useless modeling language and violates my own notions of how graphical depictions of things should work, but I digress.

Resolution of the aforementioned dichotomy takes place when we look at any printed circuit board (PCB) of reasonable complexity.

- develec.com

Every PCB has the need for power, input/output channels, cooling, but these are all just functional relationships which can be and are represented as functional blocks with signals flowing between them. Some are signals we care about, some are just housekeeping, like power.

In a PCB, islands of reuseable components (IC's) are connected in higher level idioms to accomplish some design objective. If an aggreation of chips (blocks) occurs frequently enough, the ensemble is turned into a single chip, just as the abstraction of many functional blocks can be replaced by a single block.

For a given PCB, the overall pattern is unique to the purpose of the PCB, yet it is composed of functional blocks which take on familiar and reusable patterns. These patterns repeat themselves and are therefore factorable into recognizable idioms, much like the letters, words, sentences and paragraphs of what I am typing just now.

The resolution of the similarity versus uniqueness question is given by the latter analogy. This note I am writing is a unique combination of reusable letters, words and sometimes sentences. But as the specific purpose of this note is articulated in increasing detail, it becomes increasingly unique. DNA is the same way. Four reusable symbols, CTAG, code for 64 possible sets of three (CCC, CCT, CCA, etc.) to specify 20 amino acids which polymerize (yes, people ARE plastic) to form proteins, which fold into useful configurations.

- Current Protocols

At increasing levels of complexity there seems less and less likelihood of reuseability. But in biological systems this is not necessarily true. For example a complex organ like the heart can be transplanted into another individual and work well enough to sustain life.

- ScienceDaily.com

Letters and words are reusable by necessity, lest we have the burden of continually reinventing writing and therefore communicating at the letter, word and sentence level and never end up getting anything useful done. It would be interesting to devise a language in which each idea is represented as a succession of new letters. But I will leave that glorious exercise to another.

- think smart designs blog

Something like a word processing program lives at the level of a PCB, while a font chooser lives at the level of a design pattern. But we need more than font choosers to make the world go 'round!

Design patterns are reusable, but at a meta-level, since they are not concrete. When we design a GUI certain patterns have emerged. The menu's are at the top, output and status information appear at the bottom. All languages read from top to bottom so this is quite natural. Is this because we look at the face before the feet of someone who greets us?

Consider the wonderful design documentary, "Objectified" which features Machines That Make Machines (MTMM). People by the way do this, as do all living things. A beautiful design is one that can be transparent in all its aspects and still be clearly discerned. The sheet rock in most homes, hides a network of two by fours, conduits, pipes, debris behind a facade of paint and crumbling gypsum. If a design is transparent then the machines that make machines should be just as beautiful and functional as the things they are used to make. Note that machines that make machines don't do so without first being created by their creator. In the "end game" only one level of machines that make machines are necessary because, like the functional blocks abstracted, the expression ((MTMM)TMM)TMM can be rewritten as MTMM.

- Science Clarified: AI and Robotics

Consider the assembly line staffed by pick and place robots. These are MTMM's. The CNC machines that work in concert to produce pistons, connecting rods and wheels are also MTMM's. The make technical artifacts like cars, washing machines, PCB's, etc.

Sections of assembly lines which bear a similarity to each other across technical artifacts are analogous to the design patterns of software identified by the Gang of Four. The parts they create are the reusable (think green) components, which can be recycled without further dis-assembly.

A principle emerges that at low levels of complexity everything looks reusable. A molecule, a resistor, an op-amp, a nut or a bolt. As complexity escalates, uniqueness increases. Thus reuse-ability of the aggregation becomes less and less, but not always, as in the case of DNA, where long strands are evolutionarily conserved, because that is the only way that the problem could be solved.

Two categories of tasks emerge: those that are reducible to repetition and those that are not.

- world of molecules.com

- whyfiles.org

Location-Based Radio

2010-08-16T15:26:00.005-05:00

WHAT

I want you to imagine a new kind of radio - a radio where the station is selected by its geographic location rather than its radio frequency:

Traditional Radio Tuning

Instead of a radio with a tuning knob that slides across the band, imagine a radio that uses a global view of the earth and stars:

Location-Based Radio Console

Each station on such a radio would be a small icon, rendered on or above the Earth. The icons properties might indicate the station type, frequency and bandwidth.

A location-based radio is "tuned" by selecting the location of the station of interest. In the figure below, a terrestrial radio station labeled X is at one location in the spectrum. A second signal Y is a celestial source from a different spectral slot.

Another kind of tuning is possible - a radio station can be located by first clicking on its position in the spectrum and then observing its physical location.

HOW

There are several ways we might achieve a location-based radio. Naively, we might index a list of radio stations by their latitude, longitude and altitude. We might then create a program that would look up the location we selected and open that data stream, like for example, iTunes™ does:

iTunes Radio Listing

Such a user-interface, though convenient and even useful, misses a major conceptual opportunity. I propose a more fundamental and far-reaching implementation of location-based radio. One that is considerably more versatile, entertaining and enabling of discovery.

MULTILATERATION

The idea for a location-based radio was spawned by a very simple desire. I wanted a radio that would tell me whether a signal was of terrestrial or celestial origin. It takes several radios listening simultaneously to answer this question. If a radio signal is common to four or more receivers it can be uniquely located in three dimensional space using the Time Difference Of Arrival (TDOA) of the signals.

Image Courtesy Agilent Technologies

However, this required four radios instead of just one. That was bad. Perhaps if three other people could share the cost of one radio each, all could benefit. That was good. Running this idea to its logical conclusion results in the creation of a location-based radio network. We know that networks are powerful and enabling things.

In a location-based radio network, four is the minimum number of receivers, but in general more radios are better. More signals can be heard, more common signals can be found and more people can benefit. The effect compounds quickly.

For example, if a signal is of terrestrial origin, one might listen to it, or in the case of amateur radio, respond to it with a transmission. If the signal is of celestial origin, one might want to analyze it, discovering its location and structure. The former is entertainment, the latter is science. Science can be entertaining, and entertainment scientific.

SOFTWARE-DEFINED RADIO

Preceding my desire for a location-based radio was the advent of software-defined radio. Software-define radios eliminate some of the traditional hardware of a conventional radio. A portion of the physical radio is replaced by software in the form of digital signal processing algorithms. A “soft radio” is a hybrid device, spanning analog and digital worlds, hardware and software. This introduces complexity but produces a payoff - radio signals can be digitized and routed like other web-based media as TCP/IP packets. Such packets can be exchanged by constellations of location-based radios over the internet for comparison and analysis.

If these packets are time-stamped very accurately, they can be used to locate the signal. Time stamps do not occupy much space, so transmitting them from soft radio to soft radio does not create a lot of overhead. In fact, the original RF can be stripped away and just the audio portion of the signal retained - as long as the time stamps are accurately registered against the signal samples. This reduces transmission time and overhead significantly.

Digital signal processing, in the “cloud”, makes location-based radio possible. Software-defined radio enables large swaths of spectrum to be simultaneously processed and shared. So hundreds of signals can be observed and analyzed, instead of just one at a time, as in conventional radio. Location-based radio is to conventional radio like Google is to a filing cabinet.

BACKGROUND

During the second world war, there was a race to develop and use radio techniques to locate aircraft and naval vessels. The British innovated with a technique called multilateration. However it was the advent of GPS that makes location-based radio possible at reasonable cost.

CONSTRAINTS

One constraint on any radio is the band that it listens to. Software-defined radio now routinely spans AM frequencies of 530 kHz on the low end to 1.3 GHz plus on the high end. The radio spectrum from 1 MHz to 1 GHz spans four decades of frequency. Such bandwidth is within reach of soft radios currently on the market.

WHATS OUT THERE

Several companies already manufacture software-define radios that can be used as a starting point for a location-based radio network. A standard software defined radio (SDR) can be equipped with a GPS, so that its internal oscillator is “GPS disciplined”. This GPS discipline guarantees that digitized chunks of spectrum can be accurately time-stamped to within a few nanoseconds. Light travels a foot per nanosecond. So if a signal common to four radios is time-stamped accurate to the nanosecond, the location could theoretically be good to a foot. At this writing, fifty nanoseconds is an achievable goal and more than enough to provide utility. With larger networks of radios, techniques such as differential geodesy can be used to refine the location of the signal by observing common signals for longer periods of time.

IMPLEMENTATION

With just a few location-based radio nodes, one could resolve light-dimmers, microwave ovens, FM stations, satellites,etc. Knowing the location of a radio source is one of the most important ways of determining its nature. And knowing the location of the multitude of radio signals impressing themselves upon us every moment of every day, is not only entertaining, it is interesting science. It is also democratizing.

A simple design could be produced and distributed would enable a location-based radio capability to be grown from the grass-roots level. It could be based on existing SDR designs of which there are several to choose from.

CONCLUSION

Imagine being able to locate every radio signal that was impinging upon your existence, by working in concert with a network of similar web-based soft radios. This has far-reaching ramifications some of which, like the internet, may be difficult to predict or anticipate. One example is the ability to track meteors, to in effect, "Catch a Falling Star".

ACKNOWLEDGMENTS

This work is dedicated to my best friend and technology partner, Marilyn Fulper, who life on earth was cut short when a car ran a red light and struck her on her bicycle.

REFERENCES

Multilateration : Locating an Object by TDOA

L. Van Warren - A Blazing Fast Introduction to SDR

L. Van Warren - To Catch A Falling Star

L. Van Warren - A Short Trek to DNA-Cutter M87

Gerald Youngblood - Four part series on SDR

Fixing Java's Epic Fail

2010-04-07T14:12:00.007-05:00

----
ACT I
EXT. NIGHT
A Grand Torino is parked in a vacant lot.
A slim figure with a gun towers over strange penguin-like figure,
"working" over a certain car.

I will speak with words of one sound.
I will not raise my tone.
I will not take this one more day.

We had high hopes for you.
Day and night, night and day.
But you are a punk.
We took it and took it.
We thought it would stop.
We thought it would change but it did not.

Here is where we are.
You can change or you can die.
It is up to you.
So what will you do punk,
now that you are five and ten?

---

He was supposed to be objective, portable and secure.
"Leaks no more" they said. "Browser-ready".

We bought in and let you work with... with your GUI's, your API's, your IDE's. You took our days our nights AND our weekends.

You were slow. Twenty times slow.

Here's the lesson punk:

TRUST CANNOT BE AUTOMATED

Sometimes you need a person to MAKE A CHOICE.
Baseball has an umpire. There is a reason for that.

Here's your choice.

FIX THIS or the strange little man gets it:

1) Enable file I/O in any context, with MANNERS

MANNERS means ASK PERMISSION:
"Strange little man wants to write file X from author Y on your computer, is that okay?"

2) Eliminate security obstructions for developers on their own machines.

Deployment is a separate step, with MANNERS

3) Enable compilation to native code on all platforms.

Gnu fixed this, adopt it.

4) Enable pipes with MANNERS.

Got that Captcha?!

Dark Flow and a Soft Radio Network

2010-03-28T15:58:00.017-05:00

To the dark matter and dark energy mysteries, we can now add dark flow...

NASA’s Sasha Kashlinsky discovered a twenty degree patch of sky between Centaurus and Vela to which 700 X-ray clusters are being pulled at 611 miles per second. The significance of this is that it contradicts predictions that large-scale motion should show no preferred direction and that the motions should decrease at ever increasing distances. Kashlinsky posits that the source of the pull is "outside the currently observable universe".

I mention this because this gives us a patch of sky to which we can point our software-defined radios and perhaps observe something interesting.

The limitation is that our radios have to either be space-borne or in the Southern Hemisphere to get in on the action. Also this "dark flow' patch occurs out of the range of the Ukrainian radio telescope data visualized in a previous post:

It is my hope to create a network of Orbs - Soft Radios that can cooperate to locate celestial signals. Orbs are wide-band radios that downlink to the web using TCP/IP 802.11 protocols. Orbs talk to each other to using ham, astronomy, and ISM bands in real time. Their locations in space time is computed using GPS-disciplined internal oscillators.

References

Game Theory: Socialism vs. Capitalism: The Hybrid Strategy

2010-02-04T12:56:00.009-06:00

It always pays to articulate the obvious. Sometimes it pays to articulate the subtle. I am going to talk about Cooperation vs. Competition. About Socialism vs. Capitalism. About game theory.

You decide if my points have merit. If there is fallacy in my metaphor, please identify it. Please save me from even one more minute of erroneous thinking, because life is short. Let's begin.

I like teaching people to do new things. I like physical education because it keeps people healthy. My belief is, that if people are healthy, they will be happier. I like to make people happy. That is who I am. Who are you?

I was teaching someone to play badminton. I like badminton because it combines agility, alertness, quickness and stamina.

The birdie can absorb as much power as a strong person can generate, producing a pop when the birdie goes supersonic. But a person of small stature can also excel. The physics of the game, “levels the playing field”.

Thus this innocent and interesting game can be enjoyed by a diverse group of people. That is another thing about who I am. I advocate things that include diverse groups of people. What do you advocate?

I can discuss the physics of the game and the aerodynamics of the birdie, but that is irrelevant to my point so I won’t. What is critical about badminton is the way in which people interact and contribute to the achievement of the game.

One day I noticed that if a seasoned player faces a novice player, the novice quickly becomes discouraged. Unless they are able to participate in keeping the birdie going back and forth, the game isn’t fun. A self-important seasoned player might obtain some joy in dominating the newer player. But as newer player becomes discouraged the game stops, resulting in no benefit to either player.

Thus emerges our first principle:

“When players are unevenly matched, competition destroys the game.”

Now in terms of coaching, teaching or participating, there is another strategy one can take.

When players are unevenly matched, the responsibility of the stronger player is to return the birdie such that the weaker player is guaranteed the possibility of returning it.

The consequence of this anti-competitive strategy is that the stronger player is now challenged to produce an exacting sort of shot, within the envelope of the weaker player’s skill. The weaker player now has the obligation to at least try to return this buffet platter of a shot. They are obligated to return the favor to the stronger player.

When this strategy is employed a very interesting thing happens. The stronger player begins to fatigue, because it takes more energy and more skill to deliver to the weaker player, this idealized shot, so that the game can continue.

If the game continues in the anti-competitive strategy, after awhile, it becomes the stronger player who withdraws because the demands of the game become so high. But the weaker player improves rapidly as a result of multiple successful returns.

Thus emerges our second principle:

“Anti-competition stresses the stronger player
while improving the weaker player”.

The game continues, but only for the duration of the stronger player's ability to endure.

I would say that these principles of competition and anti-competition should be obvious to everyone, but they were only obvious to me after fifty years of life, so perhaps not.

For the game to continue a new strategy MUST emerge. A strategy that takes the needs of both players into account. I call that strategy, the Hybrid Strategy. If you don’t already have it on the tip of your tongue, I will explain how it works.

Two players, a weaker and a stronger player start anti-competitively, enabling the game to be established, allowing the players to assess their position and skillset in the game. The weaker player becomes stronger and the stronger player (a measurable quantity by score…) eventually tires and calls for a strategy switch.

The players now engage the game in a competitive strategy. BUT, the players are now more evenly matched. The weaker player is now stronger, the stronger player is now tired. The game continues until the weaker player no longer wishes to participate, or the roles reverse from the weaker player becoming strong.

Now we have the third and most important principle:

"When both players consent to a strategy switch, the game continues."

The result? Improvement and value-added for both players. When either player does not consent to a strategy switch, the game ends.

Now in politics or government the metaphor can be applied as follows. Players can be Rich vs. Poor. Republican vs. Democrat. Brahman vs. Untouchable. High IQ vs. Low IQ. Strong vs. Weak. Coordinated vs. Clumsy. Citizen vs. Alien. Capitalist vs. Socialist Etc.

The hybrid strategy enriches everyone’s life to the fullest extent, and leads to the most important principle, “Reduction of Harm”. Reduction of Harm is a topic for another essay, but is quite useful in calculating those laws, ordinances and enforcements that are, in some global sense, best for society.

The selflessness of the hybrid strategy ends up benefiting both parties to the maximum degree.

We know this intuitively. How can we put it into practice?

Duals and Duels

2010-01-06T18:07:00.003-06:00

Point 1: Maslow's Hierarchy

Point 2: Economica:

There was a movie, directed by Dr. Charles Venus, about economics. It featured flow charts showing goods moving from supplier to factory to customer - with money flowing the opposite direction. Credit and Debit, Electrons and Vacancies if you believe in the Solid State.

At the time, the critical necessities were Food, Clothing and Shelter. Which is great for a Cave Man living in the Stone Age. For those not living in solitary confinement an updated list is:

(Economic-Necessities

Food Clothing Shelter Information

)

The last entry, information, implies communication, education, entertainment, PC's, TV's and cellphones.

Point 3 Duals and Duels:

ADC - DAC

The input to an analog-to-digital converter (ADC) is some measurable feature of the real world. The loudness of a moment in time perhaps. The output, quantized to a digital representation is a superposition of, "Yes, I heard it", or, "No I didn't".

A digital-to-analog converter does the opposite. It converts a digital number to an analog signal.

A good way to test an ADC is to undo it with its inverse, the DAC. One compares the real world to the real world run through the ADC-DAC combination. If the measurements are the same, you have a perfect ADC and DAC.

One can make a similar remark about DAC-ADC combination.

The idea is this: One can test a thing using its dual. The dual of the ADC is the DAC and visa-versa.

I find this simple idea to be one of the most useful ones I know.

VTF-FTV

A similar argument applies to a voltage to frequency converter (VTF) and a frequency to voltage converter (FTV). These devices exist on integrated circuit chips. The same chip can be run one direction to be a VTF and the other to be an FTV. It is a profound thing to convert a signal in the time domain, to a signal in the frequency domain. Each representation has its strengths and weaknesses. Moving a signal into the frequency domain makes some things, like filtering, very easy to understand.

HW-SW

Hardware (HW) and Software (SW) aren't really duals in the sense of the other examples. I have a friend who likes to move functions into software. I would like to see more things move into hardware. So we duel, in a friendly way of course. But you may be getting an idea here and I will leave you to that way of thinking.

Reading Past the End: The Knotted Universe

2009-12-15T16:16:00.003-06:00

While completing a lecture I stumbled upon Robert Scharein's thesis:

http://knotplot.com/thesis/thesis_letter.pdf

which along with its companion software:

http://knotplot.com/

enables one to generate knots:

This is knot the end. Think of milk drops. Think of cymbals. Think of resonating loops or 'strings' as in Brian Greene and String Theory. Can a string ring in different modes? Can a knotted string be ringing in different modes? Two such modes, orthogonal?

I can build a circuit or structure that will ring in several modes. But can a circuit be knotted? A loop antenna exists at the electron level and at the macro level. Such loops communicate by radiating and receiving photons. Knotted fields of energy. Perhaps deeper issues in physics, space-time and dimensionality are connected via knots.

Knots appear in organic chemistry. Left-handed glucose gives cells energy. Right-handed glucose is useless, unless you live in a world that is the mirror image of our own.

Knots appear in DNA storage on histone coils where multiple levels of recursion enable a six foot strand in each cell.

Proteins that fold correctly function properly. There are protein folding diseases. BSE (Mad Cow), Alzheimer's, Huntington's Chorea and even cataracts.

The issues of three dimensional correctness are covered with amazing clarity and brevity in this knot thesis. Knots are symbols with structure and meaning, flying all around us.

There exist symbolic algebra, symbolic geometry and symbolic topology.

Understanding how the three relate will make life easier for the implementers and students of same. Thus a rudimentary understanding of them is essential in the set of thinking primitives we require.

Delay Discounting Measures Operational Amplifier Gain

2009-09-21T15:34:00.003-05:00

As a systems engineer and professional mathematician, I sometimes notice two completely different fields are governed by the same model, equations, or phenomenology. One might never guess that the decomposition of ammonia gas over a platinum screen, has the same underlying equations as freefall from an airplane. This observation is unlikely unless one is exposed to both contexts and happens to also know the fundamental mathematics. By coincidence or luck, sometimes one stumbles into seeing the similarity.

Recently I observed this as a test subject in a medical psychology experiment called "delay discounting".

These studies characterize addictive behavior by attempting to measure a person's tendency towards impulsiveness and control of same. Impulsiveness is quantified by asking the test subject questions like, "Would you rather have $50 now, or $100 in a week?", on a sliding scale where the impulsive person will take anything in the here and now, rather than pie in the sky after some interval of time. Delay discounting behavior is a useful window into addictive and other human behaviors. Consider the show Survivor, where the contestants will pay $500 for a hamburger if they can have it right now, even if it means risking a million dollars in a few days.

In delay discounting there are four categories of questions. Gain and loss versus time, like the question above, and gain and loss versus certainty of reward.

The stunning (to me at least) observation is that after a subject answers these questions, they have effectively calibrated the gain curves on four specific operational amplifiers.

Amplifiers take small signals as inputs, and subject to variables like feedback, gain setting, and stability, produce large signals as outputs. There is a saying in electrical engineering that, "Amplifiers Oscillate and Oscillators Amplify". One may extend that saying to the world of digital filters to say, "Filters Amplify and Amplifiers Filter".

Without going into an incredibly boring tirade, let me just provide a few assertions that apply to the amplifier model.

1) Clusters of neurons sum their inputs to produce an overall action, and this is similar to amplifying a small input to produce a large output.
2) Different clusters of neurons, responsible for different activities, have different gain settings. The gain settings of these clusters can be imaged using techniques like fMRI and PET.
3) After measuring an individual's gain curves, one could actually predict (the thesis of the delay-discounting world) their propensity to engage in various addictive behaviors.
4) One an individual is characterized, one could simulate the behavior of that person with an analog or digital amplifier.
5) One could create an electronic implant to control addictive behaviors in willing individuals that are afflicted. (Implants in the unwilling are beyond the modest scope of this note!)

Addictive behaviors have a wide range of expression and involve substance and non-substance stimuli (gambling for instance). Basal ganglia disorders like Obsessive-Compulsive Disorders or OCD, may also involve the brain centers connected to addition.

Whether addictive disorders are architectural from brain morphology, neurochemical from nerve cell receptor distribution, or both, I do not know. What I do know is that the amplifier model can be very useful for characterizing both the likelihood and the expression of the behavior in individuals for which the measurements have been properly made.

In that sense, delay discounting measurements provide what engineers call, "A Characterization of the Amplifier".

This would certainly seem a useful model for characterizing behavior, in my mind at least.

Ref: Eisenberg et al. Behavioral and Brain Functions 2007 3:2 doi:10.1186/1744-9081-3-2

Boosting the Shuttle to Geosynchronous Orbit

2009-09-20T22:34:00.002-05:00

Figure Created Using Geometry Expressions™

The Space Shuttle could (theoretically) be boosted to Geosynchronous Earth Orbit (GEO) using a Hohmann Transfer Orbit. It would require two burns. The first burn would increase the speed of the shuttle from 7.62 km/sec to 10.0 km/sec. After entering the transfer ellipse 5.3 hours would elapse until the second burn was necessary to circularize the orbit. Otherwise the shuttle would stay in an elliptical orbit. This second burn would produce a change in velocity of 1.45 km/sec, leaving the shuttle in GEO orbiting at 3 km/sec at a fixed point over the Earth's surface. The beauty of these two burns is that they are both tangent to the orbits, in opposite directions, and use the minimum amount of fuel.

For verification purposes I have included links to the two programs used for this analysis. It is important when driving spaceships to have consensus before turning on the motor.

Appendix: Calculations in wxMaxima™

Tracking the 100 Brighest Satellites

2009-09-16T13:18:00.000-05:00

Robert Simpson created this Google Earth database for the 100 brightest satellites using the NORAD Two Line Element database. This database updates with changes in spacecraft position, which is useful. For FallingStar meteor-tracking work the following extensions would be useful:

1) Add trajectory paths.

2) Merge with NAVSPACESPUR so we can listen to crossings.

3) Add more satellites and sort these by type for amateur radio operations.

4) Add more information to placard display when spacecraft are selected.

Hamtrak - Excerpt from Work In Progress

2009-09-13T21:44:00.001-05:00

Added the ability to annotate RF sources streamed from data capture.

Lane Lickers Criterium - Sep 19, 2009

2009-09-13T15:35:00.016-05:00

(click images to enlarge)

Meet at Cook's Landing, Ride to ADEQ Loop, Have Fun!

Radio Light -

2009-09-05T23:20:00.006-05:00

I’ve got hamtrak, my communications monitoring program, running more reliably. It listens on my soft radio and plots pins in Google Earth as amateur radio contacts occur. I wanted to know if there was bias in the reception I was getting due to geographic, antenna or electronic factors. I let it run for 11 hours. Then I compared the picture it produced with US population as seen from space:

For this small sample, the visual correlation appears representative.

A Solution to the North Rising Sun

2009-09-04T01:00:00.003-05:00

Lately as I ride across the pedestrian bridge at sunrise, I have noticed the sun has been rising in the north. Having been informed that the always rises in the east, I found this perplexing. The trouble turns out to be the accumulation of two interesting factors.

1) The pedestrian bridge does not head due north, it is rotated 15 degrees towards the east. Picture:

So believing the bridge to be north-south was problem one.

2) The sun does not rise in the east. Tomorrow (9/4/2009) it rises exactly 9 degrees north of east. But back in July when I was first having the problem, it was rising 28 degrees north of east. As late as August 4, it was 21.4 degrees north of east. Moreover just before sunup, the sun is another couple of degrees north of east, when its light is beginning to fan out across the sky.

3) Accounting for the early light makes 30 degrees north + 15 degrees of bridge rotation, so the sun APPEARS to be rising at 45 degrees north of due east and that surely looked wrong. I noted this out fearing some sort of cosmological malfunction of my brain or dire state of misinformedness.

4) The sun does not rise in the east, it rises in the north east, in the summer and the south east in the winter. This is paradoxical since the winter sun rides lower in the southern sky as the northern hemisphere tilts further away from it. It rises in the east only one day of the year. This year that will be September 23 at 7 am CDT, a day after the equinox. After this the sun heads south of east for its rising reaching a of maximum southness of east of 28.6 degrees around the solstice, December 21.

5) Riding on the bridge, the sun will appear to rise in the east on Halloween morning at 7:15 am in a suitable tribute to my distress. The next day we reset our clocks introducing a new kind of biological confusion.

A Short Trek to DNA Cutter M87

2009-08-31T12:53:00.020-05:00

Tonight I was watching the city of my old workplace, JPL, burn.

While doing so I ran across UCLA data on Messier object M87, a galaxy that contains a supermassive black hole.

I opened a certain Google Earth database built from the Ukrainian observations and found out that, indeed, this RF source is one of the brightest in the universe.

But for the first time I had a possible name for bright source GR1228... could it be M87?!

M87 is very interesting because it contains a spinning black hole that is the mass of six billion of our suns, diversely radiant in frequency and direction. It has been observed at frequencies from as low 16.7 MHz, through microwave and optical frequencies, up to gamma ray frequencies. Extremely wide band radiation. Thus, it is reasonable to assume that it is a strong cosmic ray emitter as well. As such it represents a "DNA cutter". M87 gamma rays cause the emission of ultraviolet light when the upper atmosphere of Earth is impacted.

I needed to make sure that G1228 was M87, so I did some calculations and found a discrepancy between the M87's position in Google Sky and its position in the Ukrainian radio telescope database:

Now M87 has neighbors and GR1228 has neighbors, but none are so bright in the radio spectrum.

For the time being I will assume that some kind of atmospheric refraction is at work and for pointing purposes M87 is a good starting point for listening to GR1228.

I was most curious to know the current position of M87 relative to our daily experience, so I fired up Hallo Northern Sky, a free astronomy program that does time lapse on all known planets, stars, constellations and Messier objects. Running planet and star paths, past, present and future is just amazing.

Now M87 is on a line between Arcturus and Denebola. The “Star of Joy” Arcturus is the fourth brightest star in the sky and Denebola is only 36 light-years from earth.

Today for thirteen hours M87 is exposing us to its DNA splitting radiation, starting at 9:23 AM CDT this morning and ended at 10:37 PM on a route slightly more overhead than the sun.

M87 makes a good calibration standard for celestial radio location activities. I would like to know how fast M87 it is spinning, its strength as a cosmic ray source, what kind of antennae one might use to track it, and if it is truly the same object as GR1228.

A Fence In Space...

2009-08-18T22:37:00.005-05:00

For the past couple of days I have been listening to satellite crossings from the Kickapoo Space Radar. NAVSPASUR is part of the North American “Fence” that operates along the a great circle fan crossing the US. The "post" in Kickapoo is at latitude 33.558, the second tack to the left of my home in Little Rock (the red tack). One can listen to objects crossing the radio fence using Stan Nelson’s station in Roswell, New Mexico. The broadcast is in real time.

For a real treat, the NASA Java Applet JTRACK-3D allows one to view which of 900+ satellites are in crossing the fence at any given time.

When a space borne object crosses the fence it chirps. With practice one can distinguish satellites from meteors. An audio chirp and no satellite, means a meteor or a satellite crossed that isn’t in the public database. I heard two while writing this sentence. Notice that the four platforms above all have orbital periods of around 100 minutes.

Platforms which cut obliquely like ORBCOMM FM 36 have a different audio signature than those with highly inclined polar orbits due to their longer dwell time in the RF swath. To some degree the chirps are unique and I wonder if a blind person could actually get to where they knew the satellite by its chirp. Locals will be happy to know that there is a “post” in the space fence at Red River Space Surveillance Station, AR, near Texarkana.

To Catch A Falling Star...

2009-08-18T22:21:00.006-05:00

Using the light on one can see...

When any object reenters the earth’s atmosphere it gets hot. Orbital velocities are on the order of 17,000 feet per second, and much higher, and the angle of reentry determines the fate of the object. If it enters steeply, it gets hot more quickly, and the forces are much higher, on the order of hundreds of gees. These forces can break an object into smaller pieces which then proceed along their own paths. Peak heating (and deceleration) occur between 200,000 feet and 400,000 feet, the boundary of space. Objects in this region are supersonic, and become subsonic around 100,000 feet (give or take).

If an object enters at a shallow angle, it can skip off the atmosphere, much as a rock skips along a lake. It will often go back into orbit and reentry again, but at a slightly steeper angle until it encounters the fate of the first group. If it is going escape velocity, it can skip and then just go back out into another orbit, but this is not the most likely scenario.

When an object enters at an angle of between 2 and 8 degrees (give or take) it undergoes a smooth and controlled reentry, pulling only a few gees. All objects that encounter the atmosphere create a boundary layer of ionized gas. This does several things. First, it attempts to melt the skin of the object. Second it reflects RF internally. Third, and most importantly for us, the layer of ionized gas creates a streak in the sky that is an effective RF reflector. Because of the conical shape of this streak of ionized gas, the reflector does not reflect the same in all directions, the fancy word for this is anisotropic. It polarizes the RF, favoring some orientations and frequencies over others, just as your Polaroid sunglasses do.

Because this reflector is not the same size in all directions, it will favor some frequencies along its long axis and other frequencies along is short axis. One could (and may hams have) broadcast against this reflector and used it as a relay until the cloud of ionized gas cools and dissipates. But broadcasting against this reflector is not necessary, as the sky is full of signals that are already bouncing off of it, like VOR stations for example. When those signals are located using SDR, GPSDO and multilateration, they can be combined to create an image of the shape of the reflector.

This image of the shape of the reflector provides the trajectory of the reentering object. The size and frequency response of the reflector provides information about the size, position and velocity of the object. Combining this information can be used to determine where the object landed, by solving a differential equation called the initial value problem or IVP. IVP says find where the object is now, based on where you saw it last, and how it was moving.

This is how you catch a falling star.

EVCalc2: A Calculator for Electric Vehicles

2009-07-02T17:25:00.017-05:00

Who has time to read? You can just download the calculator here.

If you want to know how it came about, the story goes like this: About four years into my engineering career at NASA's Jet Propulsion Laboratory, I got the chance to attend a series of lectures put on by Aerovironment at Caltech. Aerovironment was an early green company, maybe the first with a lineup of such heavy hitters. The lectures were entitled the "Sunraycer Lectures". They detailed how Aerovironment had won the Australian Solar Race in a car called "Sunraycer". Official sources say GM put almost two million dollars into the Sunraycer. The figure I heard was higher than that. The Sunraycer was a forerunner of the Impact. The ill-titled Impact was later renamed EV-1 and featured prominently in a movie called, "Who Killed The Electric Car". A system-by-system account of the Sunraycer was given by each of the principals: Peter Lissaman's shape, Al Cocconi's on drive train, Ray Morgan's body layout, Bart Hibbs material choices, etc. Several figures of note gave presentations on their subsystems. There was a systems engineer and a structures guy who did the "landing gear".

For a final, attendees got to do a design, I did a solar-to-steam car design intended to work around the low efficiency of solar cells and built a scale-model, but I'm getting ahead of myself.

Peter, as in Dr. Lissaman - had a famous gliding airfoil named after him. He opened with a lecture about GMR method, which stood for Goal-Method-Result. I never met Sir Edmund Hillary, the first conquerer of Everest, but Peter looked and sounded like Sir Edmund to my imagination with his bold declarations and British accent. Lissaman had decided to fair the flow at the rear of the Sunraycer with "chines", discrete panels that would allow the solar cells to be attached without bending them excessively. Later designs would smooth the tail completely, but the shape was interesting and met the fabrication needs of the time. It also made for a car with an extremely low drag coefficient, 0.125, the lowest ever achieved at that time.
Al Cocconi was an electronic genius, cut from the cloth of Apple's Steve Wozniack, but by rumor, a bit more temperamental. He had figured out that high voltage AC made for a more efficient use of a battery's limited energy compared to the low voltage DC that characterized golf-cart techology of the time. He used power MOSFET's, control circuitry and a host of cool tricks to produce a drive train that was extremely energy efficient. He later invented the first hybrid, part of which was in a trailer towed behind his car, and worked on aircraft that can stay aloft for days, but those are tales for another day.
Ray Morgan was a down-to-earth engineer who talked about how Kevlar was better than Boron composites if you're in the ER after an experimental aircraft crash, because they "don't have to pick the boron splinters out of you one at a time". Ray could build stuff, in that enigmatic Mythbuster's sort of way. He talked about "Hot Shot" glue, a methacrylate glue that allowed you to put things together fast in a prototype and how you could pound the ends of fine tubing with a hammer so you could drill and fasten them together with a bolt. He is shown here shaking hands with Burt Rutan. Morgan is on the right.
Bart Hibbs, son of Al Hibbs (the voice of the Voyager spacecraft), talked about Spectra vs. Kevlar. Spectra is stronger and lighter but had the disadvantage of "creep". This meant that a Spectra panel or component placed under sustained load would actually change shape over time and usually in a way you wouldn't want. The load dynamics of Spectra, from the slow responding viscoelastic ones, to the high speed stiff response encountered in parachute openings made it a questionable material in some sense. A generation of skydivers would discover this the hard way. Bart was smart like his dad and didn't miss details.

Paul had a habit of only hiring CalTech Ph.D's for quality-control reasons, just as Honda liked Art Center College of Design people. Great if you went there, sad if you didn't. During the lectures Paul MacReady himself would chime in with the wonderful observations and questions. He reminded me of Richard Feynmann, and had most certainly attended lectures by Feynmann during his time at CalTech where he received a Ph.D. in aerospace engineering, or somethign akin to that. Paul had already distinguished himself on numerous occasions, the most notable of which was his winning the Kremer prize for the FIRST human-powered flight. Paul had worked on the wing of the DC-9 and asked himself, "What happens if you cover it with clear plastic sheeting instead of aluminum?" Paul had a knack with doing calculations that simplified things and figured out that a person on a bicycle produced sufficient power to keep such a wing aloft. The early prototype was secreted in a hanger with a landing gear of toy firetruck wheels. The final version hung in the Smithsonian.

One thing I remember was Paul, or by title, Dr. MacReady was defining specific energy in an easy-to-apprehend way. A battery had enough energy to lift itself so many feet. Different battery types could then be ranked by how far they could lift themselves and indeed any energy storage or conversion scheme. The Sunraycer used batteries you could make in your kitchen with silver foil and potassium hydroxide. A similar battery was used on the moon vehicles. Light and powerful, the name of the game in electric cars.

Now all this took place in the context of yours truly bicycling back and forth to work, and I got really tired of breathing LA exhaust fumes, which drifted north to Pasadena and clung in an opaque and stupefying fog that hid the mountains that would light on fire from time to time.

After finishing the course, it all seemed kind of straightforward, except for the two-million dollar part. It came about that a certain fellow and I cooked up a scheme by which we might retrofit existing cars by removing their internal combusion engines and replacing them with a drop-in "electric-car conversion." We picked the Geo Storm as a starting point because it was trendy and quasi-aerodynamic. The sales guy was more than happy to hear this.
I immediately began mechanical design of the "module" and collecting the components for a prototype, sinking about $30,000 into credit card debt in the process. The fellow that I had originated the concept with parted ways with me, and I was left holding the bag and running out of funds, never finished the prototype. Coincidentally, there was almost no demand for electric cars. Later simulations would show that our "modular motors" concept was somewhat ill-fated from the start. If I had done these simulations at the beginning of the project, this would have been understood with considerably less pain. The mantra that emerged from the simulations was, "Electric? Half the Car at Twice the Price", due primarily to the range limitations of the lead-acid and nickel-cadmium battery technologies of the time.

So I decided to take the basic parameters of an electric electric car, including hybrid APU's and solar panels if desired and codify them as a set of calculations. The sophistication comes from the number of related issues, "pushing on this pulls on that".Those calculations can save you a great deal of pain, dollars on the cutting-room floor, and get you closer to realizing the ideal of a practical electric or hybrid electric car. I ask a few dollars for the software, but according to my experience, its a pittance compared to $30,000...

Van / wdv.com

Filamentary Rotations

2009-06-30T09:15:00.007-05:00

I don't know where to begin, so let me just get a few ideas on the table, to see if a whole will emerge.

A degree of freedom is something like movement in the x-direction. Move over, move back. This degree of freedom is big, because we can see the movement if it is large enough.

So we might call this idea of a freedom of movement in the x-direction a dimension.

A line of this movement, or a filamentary curve is something we can slide a bead along. We assume that we can label subsequent positions of the bead as we move over and move back, and if these labels are consecutive numbers, we can use them to say where we were, where we are, and where we will be.

This filament of possible movement is so large we will call it a large dimension - a large degree of freedom.

But now take the bead and twirl it. The bead can also have another degree of freedom, a rotation.

But assume for a moment that we allow the bead to shrink, ever smaller and smaller, till it is just the size of the filamentary curve itself. We can talk about the rotational station of this bead, but the degree of freedom itself is curled up, too small to see, so we might call this a small dimension - a small degree of freedom.

We can also think about labeling how curled up the bead is by naming the turns or parts of a turn the bead has made. If these names are consecutive numbers we can use them to say where we were, where we are, and where we will be.

Now we are ready to talk about the first idea.

If we have something that is moving in a large dimension along a curve or line, we can resolve this movement as movements along a set of complementary axes. Then we can say that movement along our arbitrary filamentary curve has this much movement in the x-direction, this much movement in the y-direction, and we can use these pairs of labels as perfectly adequate alternative names for the position of the bead along the arbitrary filament.

If you have ever spun a bicycle wheel and held onto the axle in each hand, you will know that the wheel doesn't like to be tilted. It resists this tilting with an inertial force called the gyroscopic force. The gyroscopic force wants to keep the wheel spinning in its original direction and complains by resisting if the wheel is tilted to spin in some other plane of rotation.

All the points on the wheel except the very center, can be represented as translations through space, they aren't rotating at all! But the very center of the wheel (we pretend the axle is rotating too) has an axle, an axis of rotation, and there is an infinitesimally-wide dimension where the movement is pure rotation with no translation. This is a small dimension, because it can never be seen. A more apt name for it might be an invisible dimension.

If the bicycle wheel became like the bead, and became infinitely small, it would have no gyroscopic force. So it could be spinning in one direction, and then that whole assembly could be spun in a second direction and we could resolve spins in one direction into components of spins in multiple other directions as we did with translation above.

Now for the second idea.

If we count up the directions that we live in there are three, and for each of these directions there are three rotational degrees of freedom. Then there is the passage of time. So we really live in a six dimensional sort of space, if we count the invisible dimensions of filamentary rotation, seven if we consider time to be a dimension, but it doesn't have the same freedom as the others. We are stuck in it.

The third idea.

I should stop here, but I am afraid I might lose an important idea, so I will just add something that I find interesting. We rarely talk about the position of a photon. We can talk about where it originated, or where it might be after a time, but the native state of a photon is not really its position, but rather its velocity, which in a vacuum is just c - the speed of light.

But this is a translational velocity and I want to know if there is also some kind of native rotational velocity of a particle, say a photon, or even some other kind of a fundamental building block, perhaps an electron. The spin of an electron is one of its four pieces of state information. My question is, how fast is it spinning?

So putting the last two ideas together we see that it isn't just where something is that is its native state, but rather how fast it is going that characterizes something important about it. How fast something goes is a degree of freedom - a dimension also.

If we add up where things are, and how fast they are going in translation and rotation we come up with 12 degrees of freedom, or 12 dimensions. That plus time makes 13, which just happens to be my lucky number...

An Excerpt from Ham Radio Field Day 2009

2009-06-29T16:07:00.006-05:00

Because of an exhausting 50 mile bike ride in the hot sun, I couldn't make it to Field Day on Saturday. I woke up late on Sunday, hoping to make some kind of belated appearance.

Just for fun, I started my HamTrack system at 9:47 am - a mashup of Google Earth, CW Skimmer, and C++ programs, glued together with some Unix tools, sed, grep, awk, along with the usual database fiddling and geolocating.

It is an end-to-end automated signal tracking system that translates RF morse code into pins on a map. So I left it running and headed over to the real Field Day, where, after catching up with my buds, I managed an impressive 2 contacts 15 minutes before the end of the event at 1 PM.

When I got home I discovered that 308 stations made 917 calls while I was gone, illustrated as pins in a map below. As in the 24 hour case, (previous blog), pins are colored by frequency, red for 6.9 MHz, blue for 7.1 MHz and spectral coloring in-between. My pin AE5CC is arbitrarily assigned red so I can find it in the sea of pins.

You will need the Google Earth browser plug-in to view the interactive map, and it takes a few seconds to load the data - about the time it takes to read this. If you don't use Google Earth, you're missing the best thing since sliced bread. - AE5CC

An Extreme Soft Radio Adventure - 24 Hrs @ 7 Mhz

2009-06-15T22:31:00.041-05:00

After some antenna simulations using 4Nec2 (by Arie Voors) I wrapped a wire around my townhouse to create a loop HF antenna. I was curious if it was working and how the actual propagation pattern compared to my predictions. So I left my software defined radio, a Softrock 6.2 (by Tony Parks and Bill Tracey), running for 24 hours. It turned out to be quite an adventure!
Results: 1138 stations made 4907 calls, illustrated as pins in a map below. The pins are colored by frequency, red for 6.9 MHz, blue for 7.1 MHz and spectral coloring in-between.

Mouse over the map to see calls from the Island of Midway to Puerto Rico in longitude, from Alaska to Florida in latitude.

You will need the Google Earth browser plug-in to view the map, and it takes a few seconds to load the data - about the time it takes to read this. If you don't use Google Earth, there is an image at the bottom of the page. - AE5CC

Printing Circuits

2009-02-08T20:38:00.013-06:00

While talking about building circuits, my very talented friend said to me:

“For me, soldering is a way to turn money into smoke.”

If you think about it, soldering is a very primitive activity. It is a cauldron of molten metal from the Middle Ages whose sole alchemy is making a single connection. A connection known for toxicity and burns. Toxicity, because until recently solder was full of toxic lead, and some are talking about returning to lead because of the whiskers that form with lead-free solder (ROHS compliance). Burns? Burns on both hands from soldering accidents over the years. None of which confer the ability to keep from getting burned again. Solder for regular people melts at 360 degrees F. The iron is over 500 degrees F. A soldering iron left unattended can burn down the house.

Most metals conduct with low resistance. You can, if you try hard enough, get other things to conduct, like certain plastics, but they are never as good.

We are children of the integrated circuit, invented by Jack Kilby at Texas Instruments in 1958. From then on printed circuits took off. Now you can get almost any circuit you can think of for FREE in something called a sample program. You ask the vendor and they send sample chips for free. Then you make something, and if it is a hit, they make back their money because you buy the reel of 15,000.

So we regular people could stand on the shoulders of giants but for one obstruction and that obstruction is soldering.

Soldering makes a metal-to-metal connection, nothing more than a bit of metal-to-metal logic. Now is the time to retire that connection to the Middle Ages.

That would have happened but for one little bug, one little fly in the ointment and that fly is capacitance.

Most of the time, capacitance is your friend. Want to smooth out the bumps in the road from power or switching? Install a capacitor. But when you want things to happen fast, capacitance puts on the brakes.

This bad kind of capacitance is aptly called parasitic. The solution is to use short or if possible, non-existent, wires.

One might say, "Why not cancel that capacitance with a little inductance? After all they ARE opposites aren’t they?" Well adding inductance to capacitance only throws gas on the fire when it comes to slowing things down because of one itty-bitty formula. Like its friend, E = mc², that formula is absolutely magical. It is (drum roll please):

Where L is inductance and C is capacitance. If you want to go fast, you have to make L and C small. The smaller you are, the faster you go until you aren’t there. Like Dylan said, "I'm glad I'm not who I am!" You’re traveling the speed of light, trading inductance for capacitance, in waves that shoot through space.

So what do I want already?

I want to be able to sit at my computer and design a circuit that uses a whiz-bang IC and then I want to click PRINT and have the circuit pattern ready to go. Then I want to GLUE the IC and other parts down to the metallic pattern printed on paper, fire it up and watch it blink or glow or do whatever it needs to.

And I don’t want the whole process of printing and gluing and firing it up to take more than 5 minutes, because that is really about as long as I can stand to wait.

And if I had that, I could make all kinds of things, like radios, and robots and glasses to see Dimension-N, just by printing and gluing and firing them up.

And I don’t want this just for me or my friend, I want it for everybody. I don’t want to build a million dollar lab and make a hundred thousand dollar machine.

I want a hundred dollar machine and two dollar glue.

Then I can live in a world that we can make a better and more interesting place.

Sunlight at the End of the Tunnel

2008-07-09T14:44:00.008-05:00

Here is the performance of a certain solar cell company as seen from Google finance. Solar is up 1157% over a 34 month period. "Solar has tipped", to quote Malcolm Gladwell. I put this chart at the end before, but nobody reads that far anymore.

Sometimes I like to look at what the market is doing to see what collective wisdom is currently in force. This lets me see if what I’m thinking is what the rest of the world is thinking. I would just hate to be out of step. Here is a graph of fossil energy stocks for the past 34 months. Up about 50% on average. Not quite like solar.

Energy is in blue. US industry is in red. The value of energy is rising faster than the dollar or the value of industry. There are 334 energy companies. Over half, 186, of these companies are worth a billion dollars or more. One company, Exxon is worth half a trillion dollars. I took the time to add up their values. Their combined value is 4.13 trillion dollars. If you gave 4 million people a million dollars each, what might they do? At least be quiet, right?

Now let’s look at what the market says about coal. Maybe it will say, “"Say No to Coal"”, and we can take our yard signs down.

Nope. The market says coal is increasing in value more rapidly than gold. Here is gold over the same period:

There are 22 coal companies with a combined value of 103 billion dollars. One company, Peabody Energy is worth 21 billion dollars. Guess we better leave the yard signs up. But there is one piece of good news. Solar cells are rising faster than gold or coal or most anything. Over 1000% in the last two years. Don’t you wish you had been in that?

PC Security Checklist

2008-07-08T14:14:00.026-05:00

As more activities migrate to personal computers, system security becomes a greater concern. Threats to PC security include viruses, Trojans, worms, phishing schemes, buried processes and distracting scams. This note is Wintel-centric but applies to Mac and Linux boxes as well. This note addresses five categories of personal computing security.

A) Physical and Site Security - Routers and Locks

The web connection coming into your house is just another sewer pipe. Treat it accordingly. Use a router, lock it down.

1) Avoid connecting your DSL or cable modem directly to your computer. Instead,isolate your IP address by placing a router between you and the outside world. This also gives you additional ports that you can control access to and from. A router makes it difficult for an outsider to see your IP address (your internet phone number) or your MAC address (your hardware unique identifiers).

2) Install your router where you can see it. Control physical access to it.

3) Change your router name and password to something besides admin, admin.

4) Change your router IP address to something other than 192,168.1.1. Your browser will remember the new address. The router address can be reset by rebooting your router, but not without physical access.

5) The internet is NOT ham radio. Goodwill, Character and Integrity do not apply as in the licensed arts. Use 128-bit WEP or better encryption. Any device that connects to my router (the internet equivalent of a repeater) must have permission.

B) Soft Security - Anti-virus Software

You can do everything right and still get infected.

1) Install good anti-virus software. I currently use McAfee because it comes free with my Scottrade account and I can run three legal copies of it on other computers in the household. I have used Norton, but it costs too much, expires frequently and hogs system resources. I really like the free AVG software. It is excellent and they don't try to elbow out everything else. Computer Associates gives you a free trial and then makes uninstalling a total nightmare. This goes for several other packages. If a vendor doesn't provide a clean uninstaller, don't use them, because THEY are a virus.

2) Use firewall software. Insert exceptions for required sites and services like Echolink.

C) Email Security

Scan inbound and outbound email and attachments using anti-virus software.

1) Don't open attachments from people you don't know.

2) Google gmail allows you to report items as spam. Use it.

3) Report fraud and phishing emails to their respective agencies including the ISP, Paypal, Ebay, FBI and Attorney General. Some ebay frauds have been really authentic looking. Check for spoof URL's before responding.

4) Keep a primary email account, and route all other email accounts to and
from it. This is for convenience as much as security.

D) Browser Security - Plug-ins and Spyware

Try Firefox 3.0 or later. It is multi-platform, open source, and accountable.

1) McAfee red lights troublesome web destinations, including bad ham radio destinations which are rare. I average 490 searches a month so this is quite handy. Other products also do this. Do not let anyone or anything obstruct your access to good information.

2) Don't use products (e.g. Real Video) that monopolize services such as video display and attempt to be the end all. If you give them your name and address you will get on "some list". Some lists go everywhere. Some programs will leave background processes running to report back to the mother ship. Besides invading your privacy these make browsing and computing slow.. AT&T Yahoo DSL is notorious about filling your PC with wasteful market-driven processes. They have destroyed the quality of many a newcomer's experience by marketing them to death. Too many choices.

3) Use Google Safe Search to avoid sites that are a frequent source of viruses. Your computer will get sick. It's karma.

4) Use Microsoft AntiSpyware. Forced by their own losses to develop this product, it works and its free. It is fairly lightweight, process-wise. Enable the auto-download, but require them to ask permission to install. Keep track of what they are adding or subtracting from your computer. Their track record requires them to be supervised.

5) Avoid illegal download sites for music, videos, or software. Your computer will get sick. More karma. Why steal? You will have to make a list like Earl.

E) Kid Security

"Little eyes, watch what you see..."

1) Put kid computers in a public place like the kitchen.
2) Check your kids browser history, chat, IM, Skype, often.
3) Facebook trumps myspace, but not by much. Check online friends and memberships often.

Conclusion

We live in the age of hot and cold running knowledge. Anything that obstructs access to this knowledge is a loss of freedom.

We also live in the wild west of the information age. Forewarned is forearmed.

L. Van Warren - AE5CC

Antenna Gain

2008-04-09T23:55:00.008-05:00

Gain patterns can be drawn for microphones, radio antennas and light reflecting from surfaces. They are both informative and beautiful. The following images show the gain of a certain "wideband" herringbone antenna as frequency increases. Gain is simply the sensitivity of the antenna to a signal in a given direction.

When you tune a radio, you are selecting which frequency you want to listen to. But your antenna has to be cooperating by being sensitive to both the frequency of that station, its location, and how the signal bounces off the sky, land, water, trees, mountains and buildings.

So to begin we tune to 1.0 megahertz on our radio dial. In the pictures that follow we will increase the frequency on our radio dial by a factor of ten with each click. That makes for pretty big jumps. I hope to animate the in-between's soon. There are so many variables one must decide what to show first. In the meantime here is a keyframe warm-up starting at the promised 1 MHz. Captions are below the images.

You Say Tomato

1 MHz - Radially symmetric pattern, more gain at top than bottom.

I Say Potato

10 MHz -More gain at the ends than the middle.

The Edges of Lamda

100 MHz -Nature is more beautiful than I can imagine.

Butterfly Spectacular

1000 MHz -Think about this next time you tune a radio.

The last picture is around the frequency of cellphones and some cordless phones. But their antennas actually have blobby radiation patterns like the first example. Can you think why that might be so?

Copy Number Variation: The Next Big Thing

2008-03-28T01:35:00.018-05:00

Copy number variation (CNV) is an important issue in genetics.

It has a beautiful mathematical notation suggestive of text processing:

Huntington’s chorea, produces dementia that does not appear till middle age. It is caused by the presense of too many CAG repeats. What was I saying? Oh yes:

CAG repeats involve three of the four DNA bases, Cytosine, Adenine and Guanine:

If there are too many CAG’s in succession on the short arm of chromosome 4, that individual will develop Huntington’s. Period. Unlike Huntington's, which is caused by repeats, there are other diseases caused by single point mutations. Recent genome studies have focused on these mutations, called SNP’s, and pronounced “snips”, which stands for Single Nucleotide Polymorphisms. This is a fancy word for one letter of DNA, being substituted for another. A bug in the code as it were.

If you live in a world like I do, where the internet is a connected series of pipes, here is how to cure someone of sickle cell anemia, a notable SNP-caused disease.

In a text editor, like “vi”, edit chromosome11.txt:

1)Find line containing beta-globin gene.

:/beta-globin

2)Code for glutamate instead of valine.

:s/GAG/GTG/

3) Save changes and exit file.

:wq

This single SNP is responsible for all human suffering in sickle cell anemia, but it also confers protection against malaria, so there is an up side.

Hemoglobin is the protein in red cells that enables oxygen transport from the lungs to the rest of the body. It tiles in four unit pillows called hemoglobin tetramers.

When the DNA recipe/gene that codes for hemoglobin is altered by a single letter, the hemoglobin forms rigid rods, polymerizing like plastic, which you can show is what people are made of.

This causes the red cells to look like a tent with a pole sticking in the wrong place. These red cells get stuck in capillaries and cause great suffering. But many diseases caused by SNP's have already been identified as such. SNP’s were the “low-hanging fruit” of discovery.

In the long term Copy Number Variation will turn out to be the next big thing, the next frontier. It is already yielding results. You heard it here first.

NOTES:
1 - Click here for more about CNV and on the images for background.
2 - One can observe an easier to parse notation for the first figure: ABCD, AB2CD, AB3CD, ABC4D3(CD), A(CB)D, the last being “inversion”.
3 - Database of Genomic Variants
4 - Visigene

That 20 minute delay.

2007-11-08T08:30:00.000-06:00

Temporal correlation between Apple and market siblings.
(black bars show synchronization)

That little issue of the 20 minute delay in stock prices is a very interesting one.

I am interested in time, maps and relationships. My computer clocks are synchronized with network clocks that use atomic standards to keep accurate time.

The markets slid yesterday. I checked them first thing today to see how they would respond at opening. I was surprised to find that market reports that I thought were real time are not.

finance.google.com offers an interactive market graph.
As of 9:21 Eastern time, no data.

scottrade.com offers market data to subscribers, which I am,
As of 9:25, no data.

excite.com offers a thumbnail survey that claims a delay,
As of 9:30 Eastern time, no data. Curious.

Is there a twilight between market change, and the rest of the world finding out about it?

Does this delay provide an advantage to the real time trader?

The image above is from an exhaustive numerical analysis to determine the connectivity of various stocks.

Electronic signals travel at nearly the speed of light.

An electronic signal, as a stock price, can circle the earth 7500 times each second.

A fast video gamer can react in less than a tenth of a second.

A computer can react in about a microsecond.

I would wager, that until that 20 minute delay is removed, some people with access to real-time signals and computers will continue to profit exorbitantly off the losses of others.

In trading terms, a half hour is an eternity. It is the chasm between rich and poor, just and unjust, leading and following.

Apple vs. AMD tracking over a year.

Forte! The Loudest HF Radio Source

2007-09-14T14:14:00.000-05:00

.

I finally got my program going for visualizing celestial radio sources. It was one of those stay-up-all-night-cause-its-too-exciting-to-sleep kinda deals. The push came at was the end of a week-long programming binge. Now its rehab time.

Here are some preliminary results, seen from several points of view. In these images, the size of the blob is the loudness of the source. The color of the blob is the spectral index. Purply blobs are blue-shifted "hot" sources. Orange-red blobs are red-shifted and thus cooler, in the radiant sense.

To give you a sense of this, here is Andromeda, by its lonesome:

Here it is hanging with its radio friends:

Some friends are louder than others:

Turns out this source is near a couple of black holes in the catalog.
One is "feasting" the other is "spewing". Quite the cosmic party.

I find that very exciting...

You can too. The Google Earth kml file may be downloaded here.

- Van

L. Van Warren MS CS, AE
web wdv.com
FCC AE License AE5CC

"Slow is Fast and Fast is Slow"

Third Rock: Get Your Galactic Freak On

2007-09-12T05:53:00.000-05:00

Made some more progress getting the Ukranian RF data loaded into Google Earth.
Many of the glitches are gone and I am getting better coregistration.
Here is an example of a “possible” optical correlation with a radio source.
In galaxy zoo this would be classified as an elliptical galaxy. Perhaps it isn’t!

I still have to size the radio emitting sources by their flux, which is a little harder due to the grammar, but is coming into reach. There are a few really loud sources. I can’t wait to get my freak on them. But at 5:30 am, its probably time to go to sleep! This is so exciting, it is literally making me sick to my stomach. I am having a lot of anxiety with each step. This is very powerful stuff. Leverage. And it is so new. No eyes have ever seen this massive correlation.
Don’t know who to tell really, so you guys are it! I will release a layer soon and you can load it into Google Earth yourself!

All the red spots below are radio sources.

All the best,

- Van

L. Van Warren MS CS, AE
web wdv.com
FCC AE License AE5CC
Slow is Fast and Fast is Slow

Second Look: Visualizing Radio Sources

2007-09-11T01:30:00.000-05:00

This evening's work consisted of rendering the sources as point emitters, instead of envelopes.

Here is the sky before and after visualizing radio sources:

Before:

and After:

The dark band appears to be a gap in the data.

Next tasks are to render sources by their strength or apparent radio brightness, and clear up gaps in the data.

- Van

First Light: Windows To A New View of Space

2007-09-09T23:35:00.000-05:00

There is a saying in telescope construction: “First Light”.

It is at that moment when one finds out if all the work will have a reward. It can be so much work. Just now, while a retrospective of Pavaroti ran on CBS, my radio telescope mapping program got its first light. I am visualizing the Ukrainian UTR-2 Radio Source Catalog.

Here are two pictures showing the sky as we used to see it, and the radio sky as we can now see it. This is very rough, and maybe even wrong, but it shows that all the pieces can talk to each other, and that is the hard part.

Here is what the sky looked like before:

Here is “after” the first light. Each red window is a radio source. I promise to improve this, but it’s a start. There are 12,000 observations from over 2000 galaxies, quasars and galaxy clusters emitting on frequencies you can hear on a short wave radio 10 – 25 MHz. Hopefully we can do that too!

It is so exciting! Thanks to all the astronomers in the Ukraine and the engineers at Google who made my work visualizing the UTR-2 catalog possible.

Rosette Nebulae with Ukraine 10-20 Mhz Radio Windows

Zero Point: Visualizing 16.7 MHz Celestial Radio Sources:

2007-09-08T03:22:00.000-05:00

This evening was spent processing the Ukraine Russia Radio Telescope Database and extracting celestial coordinates, spectra and signal strengths for 16.7 MHz RF Celestial RF Emitters. Results were obtained for the following numbers of objects:

Quasars: 118
Galaxies: 142
Galaxy Clusters: 15

Subtotal: 275

Other Grade A Emitters: 749 // high quality measurements
Other Grade B Emitters: 596 // medium quality
Other Grade C Emitters: 510 // lower quality

Subtotal: 1855

Grand Total: 2130 celestial radio sources

This required many computational operations, data verification and conversion passes. Scripts were written that convert the raw catalog into a consistent, normalized and usable form.

Now that the database is ready, I intend to plot these radio sources in Google Sky so we can “see” their distribution and galactic neighborhoods. M31, Andromeda, is my focal point, but I’m very excited to have many sources to consider. Color=Frequency, Size=PointingRolloff, Brightness=Flux. It will take me a few days to produce the KML channel. Unix makes cleaning and sifting through the data much easier. This will help us know where to point our software radio antennas. Wish me luck.

A Switched Variable Capacitor

2007-05-12T01:46:00.000-05:00

Lately I have renewed my interest in wideband radio. The question is, what is possible now?

Turns out, it’s all in the amplifier.

Texas instruments makes a very interesting wideband radio frequency (RF) amplifier. It is called the THS3202. There is a saying in radio, “DC to daylight” to describe this kind of part. The 3202 goes from 100 kHz to 2 GHz, not quite daylight, but pretty close.

THS3202 Wideband RF Amplifier -- Texas Instruments

That is sixty-five times more bandwidth than the Hammarlund of the previous article. That’s a lot. The 3202 weighs much less than a gram. That’s a little. You can see it in the center of the board above.

Here is a circuit showing the THS3202 in action:

3202 Amplifier in Action -- Bruce Carter TI

Finding the Needle in the Haystack

There are three ways of teasing a given signal out of the haystack of broadcasting and noise.

1) Resonate incoming RF through LC tank circuit to select a specific signal.

2) Multiply all incoming RF by a frequency you choose and generate.

3) Bandpass filter all incoming RF to amplify the desired frequencies and quench the rest.

Most radios use methods 1 and 2, heterodyning to demodulate the incoming signal. Here we focus on method 3, homodyning, made possible by advances in amplifier technology...

Filtering

Trump, Stitt and Bishop of Texas Instruments have created a program called FilterPro™ that enables the accurate specification of filter banks for a wide range of frequencies. Low-Pass, High‑Pass and Band-Pass filters can be designed using Butterworth, Bessel, Chebychev and other common filter paradigms. FilterPro™ allows cascading stages of bandpass filtering that use identical components, except for the filter capacitors. As a quick example, consider the following two‑ pole filter centered at 500 MHz:

Two Pole Bandpass Filter created using FilterPro™

An iterated use of the program produces the following range of component values in a five-pole bandpass filter:

Capacitor Values Required for Wideband Filter Tuner

Five stages of the filter shown above enables a very wideband filter to be created that can serve as a radio tuner. From the graph we can see that the bandpass filter not only filters, it amplifies the signal of interest by 40 decibels (dB), or a factor of 10,000.

A Switched Variable Capacitor

“Back in the day” variable capacitors with consecutive ganged stages were used to address the tuning problem. They looked like this:

Air Variable Capacitor from Wikipedia

Modern versions of such capacitors have a range of capacitance from 15 picofarads to 384 pF. Synchronizing 10 instances of 15000 pF each would require 390 such units.

The trouble is that for each section of our five pole bandpass filter, we required two capacitors whose values can range from 1 pF to 15000 pF, that is, five decades of variation. A coordinated five pole array requires ten wideband variable capacitors operating in near-perfect unison. Accomplishing this with combinations of mechanically ganged variable capacitors is not practical.

This paper explores the creation of a variable wideband capacitor constructed using arrays of surface mount capacitors and solid state relays.

Novacap Capacitors and Teledyne RF Relay

The questions are:

· What topology of array?

· What form of switching?

A useful design would require.

Clearly the equivalent series resistance (ESR) of the switched capacitor should be as low as possible to maintain the idealized properties of a capacitor.

Two solutions come to mind. Both give rise to interesting mathematical analysis. We will start with the simplest first.

Note” The term “array” will be used to talk about the ensemble of capacitors used to create a single variable wideband capacitor. The term “bank” will be used to talk about a synchronized set of such variable wideband capacitors.

Point of Clarification

A Simple Decade Array

Consider an abacus like arrangement:

A Switched Variable Capacitor from 0 – 99,999 pF with 1 pF Steps

This capacitor would require 5 columns for each of the five decades. Each column would require 9 capacitors to represent the digits in each decade. The result would be a variable capacitor of 0 – 99,999 pF in 1 pF steps. Now obviously lead capacitance would make absolute values below 5 pF difficult to obtain, but increments of 1 pF could be realized with this device. This bank requires 45 capacitors and 45 switches to accomplish this task. With surface mount technology it would be the size of a postage stamp.

The question is finding those values of capacitance.

My Favorite Radio

2007-04-16T23:20:00.000-05:00

-- photo courtesy Universal Radio

This is my favorite radio ever. It is the Hammarlund HQ-140-X shortwave receiver. It was made between 1953 and 1955, one year before I was born. When I was about thirteen I received one of these radios as part of my ham-radio pursuits of the time.

I remember listening to Canadian, South American, English and European broadcasts on it late at night when the reception, "on the skip" was good due to ionospheric conditions. I heard Al Green on the AM, telegraph coding, both manual and automated and strange warbling signals that are quite memorable. I have always wondered if these were pulsars or binary stars, but perhaps that is a bit fanciful.

Notes on Scanning

2007-04-15T17:14:00.000-05:00

I wanted to make a few notes about scanning transparencies and prints.

Epson makes a scanner called the V750. It's pretty cool. It has a built-in light box for transparencies in the lid.

In addition to the usual faire, you can scan transparent positives and negatives up to 8" x 10" at resolutions up to 6400 dpi.

At 6400 dpi, each square inch of the image is 41 Megabytes.

For a 4" x 5" Hasselblad positive or negative transparency this works out to about 819 Megabytes per image. Just remember "4x5 is a gigabyte".

If you have many film products to scan you may want to purchase an additional external hard drive that you can throw in the car and drive to your print fulfillment vendor. A 400 Gig USB 2.0 drive is $139 at this writing, but you might want to go bigger. Uploading gigabyte images is tedious at best.

Preparing Your Machine and Workspace

You will want to max out your machine with RAM. RAM is cheap compared to your time.

You will want to make sure that your machine supports USB 2.0. Dedicate a table to the scanner so that your workflow is convenient, especially if you are working in a team environment. People need room to move and think. You might also want to have a light box and a film loupe so you can review your materials prior to scanning.

A can of compressed air is useful for blowing the dust and lint off of film materials. I highly recommend running a dust remover like the Oreck or Multi-Tech in the room where you are handling film. Also wear inexpensive cotton gloves. Fingerprints contain acids that will deteriorate your materials long-term.

Connecting the Scanner

The vendor provides disks with various drivers and utility software. Plug the scanner into a UPS power strip to protect its delicate circuitry and connect the USB to the back of your machine where it will be out of the way.

Running the Scanner

After the scanner is connected and configured correctly, run some scans at LOW resolution. There is usually a preview mode but keeping the "dpi" low will let you get your feet wet without using large amounts of scanning time or disk space. After you get your workflow down, you can crank up the resolution. I suggest 400 dpi just to see how things are looking. You can also rehearse the corrections you want to make in brightness, contrast, etc without running into space or time problems.

After you are happy with your process, double the dpi to 800 and make sure everything is ok. You can continue doubling until you reach the peak resolution of the scanner. 6400 dpi is four doublings. Plan on the fourth doubling to take sixteen times as much time and disk space as your early fast runs, which should be less than a minute.

Numerical Gold: A Certain Series

2006-10-23T01:04:00.000-05:00

Consider the series:

1, 1, 2, 3, 12, 20, 300, 525, 1960, 49392, 1481760, 5821200, 164656800, 336370320, …

Do you, offhandedly recognize the generating function? This is a special series.

These are the inverses of the last solution xn to the Hilbert matrices of order 1, 2, … 14

These matrices were notorious for being ill-conditioned, they are solved here symbolically using Maxima and rational arithmetic.

Maxima notebook is below.

The solution is to the n x n linear algebra problem [H]x = b.

To reproduce these numbers, or larger ones, one can edit the file with a text editor and then drag it into the Maxima window. The last number required 2 minutes to generate on my new dual-core. To change the order of the Hilbert matrix, just change the order variable at the top of the file. It is currently 4. So a point of curiosity really. The numbers become extremely expensive to find, growing at least as the cube of n times a large constant. So to me they are a kind of symbolic gold. The 100^th number for example, is probably not knowable at the current time, but that is speculation on my part. You may notice some functional relationship that allows their simple generation thus “Cracking the Hilbert Code”.

For example

12 = 4 * 4 - 4
20 = 5 * 5 - 5
300 = 20 * 20 - 100
525 = 25 * 25 – 100
and so on.

Ref: The Code

load("eigen");
order : 4;
X : columnvector(makelist(concat(x,i), i, 1, order));
h[i,j] := 1/(i + j -1);
Unity[i,j] := 1;
A : genmatrix(h, order, order);
A . X;
B : genmatrix(Unity, 1, order);
A . X = B;
Ap : triangularize(A);
Ap . X = B;
App : invert(Ap);
App . B;