Pages

Adsense Search

Custom Search
Showing posts with label Reference. Show all posts
Showing posts with label Reference. Show all posts

22 April 2021

Best AR Mod Since Stoner

Best AR mod since Eugene Stoner invented the platform

or....

Fixing the rear takedown pin detent spring


The most commonly lost parts of the AR rifle platform are the takedown detent springs. Installing the buffer tube to the lower receiver requires coordinating everything while holding the rear takedown pin detent spring from flying out or getting crushed/pinched by the sling adapter plate (or buttstock).

Here's the permanent fix:

Tap the detent spring hole for a #4 x 1/8th" set screw. This probably should be the case not only with new lower receivers but should've been implemented from near the beginning of the platform. But it wasn't, and still isn't. But, the fix is easy.

The rear takedown pin detent spring hole is already roughly the correct size to tap for a #4-40 setscrew. The Colt specification for the lower reciever rear takedown detent spring hole is 0.093" +/- 0.004". The recommended drill bit size for a #4-40 setscrew tap is #43 which is 0.089". 


Chuck a 4-40 tap in a cordless drill and slowly tap the hole. Go slow and reverse the drill often to clear the aluminum (or polymer) chips. 



The detent spring should be trimmed the length of the new setscrew; 1/8" or 3/16", whichever length you use. 



Use a 4-40 x 1/8" or 4-40 x 3/16" NC setscrew. There is no real need to use thread compound because the setscrew has nowhere to go. But if you prefer, you can add a tiny dab of blue thread locker. 



No more spring lauches!





To save some searching, here are links to the tap and setscrews;¹





¹ Disclaimer:If you buy through the links Amazon might pay me a few cents.








10 June 2013

Misused Mathematics of DNA Sampling



Mathematics is the basis of modern technology. But it is also the basis of many false assertions. I have written previously about how statistics are (miss)used in stock market analysis. This article looks at the miss-application of math in DNA Sampling.



When DNA experts testify in court, they typically describe the probability of a false match as 1 in 100 trillion (1/100,000,000,000,000). That seems like a virtual certainty. But where did they get this number?



First a little background on DNA Sampling: Technicians extract DNA, use enzymes to cut it into pieces, process it then compare the different segments, or loci as they call it. To be admissible in court, there must be matches on 9 loci, or segments. DNA analysts typically use 13 loci, and empirical evidence suggests a random match occurs about 1 in 10 times for one loci. These two pieces of information is where the above number comes from;



(1/10)13



This is pure mathematics. The probability of two DNA samples matching exactly is 1 in 100 trillion. But there is problem – “empirical evidence suggests a random match occurs about 1 in 10 times for one loci”. This is one of innumerable cases of getting subjective probability mixed up with frequentist probability. The former measures knowledge of an event, the latter measures mathematical probability. The problem with this particular mixup is that we don’t know for a fact that random matches occur at an exact frequency of 1 in 10. There is missing information, specifically, do the random matches always occur at this rate, or are there circumstances we haven’t encountered where this is not the case?



The Empirical Case



A study was done on the Arizona CODIS DNA database that found 1 in every 228 profiles in the database matched another profile in the database at nine or more loci. This in a database containing only 65,493 entries.



Conclusion



So the miss-applied mathematical probability of false DNA matches is claimed to be 1 in trillions (depending on number of loci). Real world practice reveals a probability of 1 in 228 (or less, with a larger dataset). Which is correct? Which number should be used in court? Definitely not the mathematical one, because it is falsely applied.





Addendum

What is the frequentist probability of finding an exact false match in a database containing 10 million entries? You may be surprised to find out the odds are 51%. 




23 April 2013

The Fukushima Corporate Made Disaster


It's been a few months now since the Japanese government released their 440 page report on the Fukushima disaster.[1] They blame just about everybody imaginable, going back decades before the place was even built. But glaringly absent from the long blame-list is the company that built the time bomb - General Electric. Their poor design was as much a cause of the escalation of the disaster as anything else, but yet they're blameless. I call BS. 
Japanese engineers working on the plant wanted to modify the design to make it more resistant to...tsunami's! But bureaucrats, in awe of the venerable GE, demanded they build it just like GE said. So when the tsunami came - disaster. 
Specifically, GE designed the units with the emergency cooling units in the basement of the reactor building. Japanese engineers (and presumably any one with common sense) saw that this was idiotic, as the cooling units were susceptible to flooding.
After a couple of decades of operation, less ignorant thinking prevailed and it was decided to move the emergency cooling pumps onto higher ground. But, in an act of residual dumbness, the switches that powered the pumps were left in the basement.
The tsunami comes, the basements were flooded, and the pumps, previously moved to a safer location, couldn’t be run because the switches were underwater in the basement. Time was wasted trying to pump the water out of the switchgear. Of course that didn't work, so time was wasted trying to re-wire the pumps from an alternate source. That didn't work because cables weren't available. All the time, the reactor cores were melting down - the infamous China Syndrome. 
A second monumentally asinine design feature placed the highly radioactive used fuel rods on the fourth floor of the reactor building. Without constant cooling they generate enough heat to self ignite, resulting in a radioactive fire that could (still can) produce enough radioactive fallout to kill every human being on earth several times over. 
But, since the failure of the cooling pumps, the meltdown of the reactor cores and the resulting explosions, there is no way to cool the spent fuel rods suspended on the fourth floor. Workers are reduced to spraying water on them, further contaminating everything with the runoff. The containers previously holding the cooling water were compromised in the explosions and no longer hold water.
Various ecological and scientific groups say this situation is the gravest immediate threat facing mankind. 
If the reactors had been designed specifically for Fukushima, instead of a package design built for Kansas, there would not have been a disaster other than the temporary shutdown of production.

The cost of corporate greed is incalculable.


[1] http://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/wp-content/uploads/2012/09/NAIIC_report_hi_res10.pdf

05 April 2013

Economics Is NOT Rocket Science - Stages of the Economic Cycle



This blog was created to simplify the alchemy of economics. Economics is not rocket science, . I maintain that it isn't even a science at all. Behind the facade of formulas, theories and schools, the underlying principals are relatively simple. 

The issue is separating economics from business and investing. Both are essentially the study of people. In economics, if people do a, the result is x. If they do b, the result is y, and so on. The problem in business and investing is trying to predict if and when people will do a or b. Of course, this can be impossible, and is the reason business and investing is difficult....and complex. 

In economics there are "laws" or "rules". Economics doesn't follow the Austrian School some of the time and the Chicago School some of the time. This is ludicrous, despite the fact there is a huge industry of producing and employing economists and researchers. The Federal Reserve itself employs over 300 PhD level professionals. 

So in the interest of offering people a clear view into the obfuscated world of economics, I am re-posting an article from a couple of years ago outlining the true stages of the economic cycle. This cycle has been repeated over and over throughout the history of mankind, and despite of, or perhaps because of, our technical progress we are still subject to the same cycle. Because we are now in stage 11, it is important to know the truth.


True Stages of the Economic Cycle 

1. Hard Money. A form of currency is established to facilitate commerce. In order to gain acceptance the currency is backed by something of intrinsic value such as precious metals. This is known as Hard Money.

2. Debasement of the Currency. It is immediately evident that “free” wealth can be created by Debasing the Currency. In its most fundamental form this involves the practice of charging interest (or usury, the meaning has been exactly the same throughout history up until recent times).

3. Enactment of Legal Tender Laws. Without Legal Tender laws, implied values are self correcting and always closely match true value. Legal Tender laws greatly facilitate the debasement of a currency. The Founding Fathers knew this, Thomas Jefferson wrote: 

"If the American people ever allow private banks to control the issue of currency, first by inflation, then by deflation, the banks and corporations that will grow up around them will deprive the people of all property until their children will wake up homeless on the continent their fathers conquered".
 
The U.S. Constitution, Art. I Sec. 10 Cl. 1, states: 

"No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts;"

The Supreme Court ruled in U.S. Supreme Court - Wheaton 1827; 

“The prohibition in the constitution to make anything but gold or silver coin a tender in payment of debts is express and universal. The framers of the constitution regarded it as an evil to be repelled without modification; they have, therefore, left nothing to be inferred or deduced from construction on this subject.”

4. The Accumulation of Debt is unavoidable with legal tender laws in general, and especially in a Central Banking scheme such as our current Federal Reserve, in which the perpetual increase of debt is an essential component.

5. An Illusion of Economic Prosperity is created by the accumulation of debt. This is no different in principle from a person going on a spending spree with credit cards. They have the illusion of being very prosperous, but in reality they are destined for a reckoning when the debt cannot be paid.

6. Monetization of the Debt. As the accumulation of debt becomes unmanageable, it become necessary to monetize the debt. The debt grows so large it cannot possibly be paid. There are a few ways to “resolve” this. 

  • The most obvious way is through taxation, but this is never politically acceptable. 
  • Another way is by directly devaluing the currency. This has been done many times in history, but is also not very politically acceptable.
  • The third, and easiest (for leaders at least) is hyper-inflation. In simple terms hyper inflation erases debt by transferring wealth from individuals to government.

It is apparent that all three solutions have one thing in common – all transfer wealth from individuals to government, or more accurately, to the central banks.

7. Dilution of Currency Value The process of monetization directly causes a Dilution of Currency Value.

8. Loss of Confidence. In essence Consumer Confidence is a measure of how well the taxpayer is being fooled into thinking all is well. The dilution of his buying power caused by the dilution of currency creates a Loss of Confidence.

9. Inflation. As buying power decreases, the consumer tries to make up the difference by charging more. The merchant charges more for his goods, the laborer demands more for his services. This is classic Inflation.

10. Inflation Stabilizes as government  implements inflation control measures, but does nothing about the underlying problems, causing a:

11. Return of Inflation, quickly followed by:

12. Hyper-Inflation, which effectively erases the debt. If the U.S. experiences the level of hyper-inflation similar to Hungary in 1946/7 (42 QUADRILLION percent per month), the entire national debt could be paid off with less than a penny. This may sound like a good thing to some, but the truth is, wealth is simply transferred from private individuals to the government. This is the stage of Reckoning. It is obvious that there was no real wealth created in phase 2. This is the essence of my argument against the “Economy creates wealth” proponents. Economic trickery does not create wealth. It never has and it never will.
The wealth transfer causes:

13. Depression, which leads to:

14. Reorganization of Government. It is only at this point that a significant number of people understand the inextricable link between wealth and real money. This enlightenment leads to:

15. Return to Hard Money, and the cycle repeats.


These phases are exponential in nature. The time from the debasement of a nations’ currency to the loss of confidence in that currency can be measured in decades or even centuries. The time between the loss of confidence and inflation however, may only be weeks or months. In the later stages of hyper-inflation the loss of a currency’s value and the accompanying price increases can double in days or even hours.[1]
It should also be noted that inflation is not bad for everyone in equal measure. It is actually a good thing for those people of means who are in a position to borrow to purchase property. The reason is the same; the repayment of debts, is made in currency that is worth less than the currency originally borrowed. This is also the reason working people cannot prosper during times of inflation or hyper-inflation. Wages are generally not indexed to inflation and always lag price increases. Even in the case of the relatively few people whose wages are indexed to inflation, the adjustment is always done after the fact. Loses accumulated from the previous adjustment are never recovered.


[1] In the Weimar Republic in 1923 workers demanded, and were paid three times a day in order to be able spend the money before it lost further value. 

03 April 2013

The Misapplication of Gaussian Math in the Financial Sector

Business is about mathematics. Macro-economics is not, it is about people and reality. This is a fundamental flaw in economic thinking. And one that causes economic disasters one after another.

This is the formula for the Gaussian Distribution, better known as the “bell curve”. Most financial model up until very recently used this model. Many still do. It is used in the ubiquitous Black-Scholes option pricing model. 



However, because it is a Gaussian distribution, it does not properly account for risk (events) outside of 5σ, therefore pricing for far-out-of-the-money options are mis-priced.

In 2000, David Li published his “Li’s Function”, a type of Gaussian copula function.







Pr – Probability.. as in default. This is the variable that is solved for. In other words, The rest of the equation gives the answer for Pr
T – Time between now and when default is expected.
= - Equality used to eliminate uncertainty

F – Probability of survival 
Φ – Used to sum the probabilities of A and B 
γ – Used to reduce correlation.

Li’s Function was quickly adapted for use in pricing Collateralized Debt Obligations (CDOs) because it allowed investors to quantify risk. Unfortunately, it suffered from the same type of flaw as the Gaussian Distribution – it failed to account for unlikely events1.

Whatever other factors involved in the financial meltdown of 2008, the use of this formula was the singular major cause of investor losses. Because it failed to assign proper risk values, the actual risks were far greater than expected.

Even after the fiasco of 2008, modified versions of Li’s Function and other Gaussian Copula functions are still being used in financial circles to price multi-instrument products such as currency swaps.

Economists and financial advisers are still attempting to modify Gaussian mathematics and Game Theory to fit economic reality. But all attempts suffer the same weakness. 

It is impossible to account for all possibilities since the bounds of all possible things that could happen are infinite. 

This isn’t the case with Game Theory. The roll of a roulette Wheel or the deal of a card hand may be random, but they are bounded. There are a known number of slots on the roulette wheel, and a known number of possible card hands. The bounds of possibility in the real world, and by implication the financial world, are infinite and unknown. We do not know what possibly can happen to affect financial markets in the future. Therefore, if no one knows, how can risk be calculated? It can’t. And so the next big financial catastrophe is just around the corner.

Mainstream financial “gurus” (like Dave Ramsey and most financial advisers) mislead their clients by not taking into account the huge losses that happen regularly, but are not predicted or accounted for in their models. The fact that a lot of retirement accounts and other wealth were wiped out in 2008-12 is NOT unusual or dramatic. It is guaranteed to happen. Putting money into non-cash, non-good based instruments is reckless; no difference in essence than gambling.


Business is about mathematics. Macro-economics is not, it is about people and reality.




1. In fairness to Mr. Li, his function was theoretical, and may have never meant to be applied to real-world trades. We do not know, since Mr. Li returned to his native China and refuses to discuss the matter.








31 March 2013

The Euro At A Glance

Use of the Euro is quite a bit more widespread than a lot of people realize. To help understand the potential impact of the ongoing crisis, I have put together the following document listing countries according to nine criteria;


  • Members of the European Union
  • Members of the Eurozone (Eurogroup)
  • Current European Union candidate countries
  • Potential European Union candidate countries
  • Countries using the Euro under agreement 
  • Countries that have unilaterally adopted the Euro
  • Countries using the Euro only for international trade
  • Countries whose currency is pegged to the Euro
 



28 March 2013

Cyptus Bailout Plan In Plain English

1. Laiki bondholders and equity owners will likely lose everything. Uninsured deposits will incur loses of around 40%

2. Laiki bank will be shut down.

3. Good parts of Laiki Bank will be turned over to Bank of Cyprus. Uninsured deposits in BoC will remain frozen until recapitalisation has been effected, and may be subject to liquidation.

4. The Governing Council of the European Central Bank will provide liquidity to the BoC in line with applicable rules.

5. BoC will be recapitalised by exchanging deposits for bank equity.

6. The conversion will be such that a capital ratio of  9 % is secured by the end of the programme.

7. All insured depositors in all banks will be fully protected in accordance with the relevant EU legislation.

8. The programme money (up to 10bn Euros) will not be used to recapitalise Laiki and Bank of Cyprus.