// convert all values to ints
array_walk_recursive($versions, function(&$val, $i)
{
    if (is_string($val))
        $val = (int)$val;
});
// make to arrays the same length by padding them with 0s
function normalize($a, $b)
{
    $al = count($a);
    $bl = count($b);
    if ($al < $bl)
    {
        // add 0s to $a until they are the same size
        while (count($a) < $bl)
            $a[] = 0;
    }
    elseif ($al > $bl)
    {
        // add 0s to $b until they are the same size
        while ($al > count($b))
            $b[] = 0;
    }
    return array($a, $b);
}
//compare to integers and decide which one is bigger
// return 0 if they are equal
function check($a, $b)
{
    if ($a < $b)
        return 1;
    elseif ($a > $b)
        return -1;
    else
        return 0;
}
// sort the array
usort($versions, function($a, $b)
{
    // make sure the major_version arrays have the same length, pad with 0s to correct
    list($a['version'], $b['version']) = normalize($a['version'], $b['version']);
    for ($i=0; $i < count($a['version']); $i++)
        $check = check($a['version'][$i], $b['version'][$i]);
    return $check;
});

Vacuum ports and Adjustment Screws

My motorcycle has 4 inline carburettors, with a shared linkage, 3 adjustment screws between each pair of carbs, and the throttle connected in the middle.
The problem was that each carburettor wasn’t allowing the same amount of air through. This can be remedied with a tool called a manometer that measures the pressure difference at two points. Most multi carb setups have a small vacuum port between each carb and the engine, which is usually plugged with a screw. I took that screw out and found out it was an M5 x .8 metric thread. I then bought a hex bolt with that size, and drilled a hole down the center.

hex bolt with hole drilled through it

I then built the following tool from these plans, slipped the hex bolt into the end of the tube, filled it up with water, and balanced all of the cylinders. This took some trial and error, and I had to be careful that the carbs weren’t too far off or else there would be enough pressure to suck the water into the engine. I started on the right two cylinders, and adjusted the farthest right adjustment screw. I then moved left. When I was done, the problem was fixed, and the motorcycle was running perfectly.

DIY manometer

DIY Manometer

/**
 * Captures output from a function
 *
 * @param $callback is the name of the function
 * @return the output of the function
 */
function capture($callback)
{
    $args = func_get_args();
    array_shift($args);
    ob_start();
    if (count($args))
        call_user_func_array($callback, $args);
    else
        call_user_func($callback);
    $output = ob_get_contents();
    ob_end_clean();
    return $output;
}
$sidebar = capture('get_sidebar');
// or if it was a function you needed to pass arguments into
$title = 'Test';
$author = 'Nate Nuzum';
$header = capture('get_header', $title, $author);

// works in the newer version of php 5
$sidebar = capture(function()
{
    get_sidebar();
});
function get_sidebar()
{
    echo 'hello';
}
function get_header($title, $author)
{
    echo "{$title} {$author}";
}

Add the following to your .vimrc Set 100 to the max number of characters that you want in a line.

:nmap <c-a> ggVGgq
:setlocal textwidth=100

save and quit.

Open up a file to edit, press Control-A and voila!

<?php
// Disable the flash uploader
add_action('flash_uploader', 'disableFlashUploader');
function disableFlashUploader(){return false;}
?>

Iowa State has a high dollar deal with U.S. Bank that allows students to use their university id as a debit card. They have it set up such that, if you come to ISU, during your registration for classes, you automatically get routed into a line to sign up for a new U.S. bank debit card. And they make it seem like it is part of registering for ISU. A friend of mine called U.S. Bank about getting a loan. He asked them why he should get a loan from them if their rate wasn't that good. The service representative said, we have no reason to offer good rates, we make all of our money off of overdraft fees on college kids. Another friend of mine, over-drafted on accident. Each time she tried to use her debit card, for about 3 days, they charged her around $30. Her charges went up to over $500. We asked them why the card kept working if she was several hundred dollars in the negative, and the U.S. Bank employee replied, "We allow it to continue working to save the customer from the embarrassment of their card not working in the grocery store." I personally would much rather be slightly embarrassed by my debit card not working than to get charged hundreds of dollars in overdraft fees.

Two friends A and B meet every morning at the Grand Central Station around 7 am. Suppose the actual times they arrive are independent and uniformly distributed between 6:55 am and 7:05am. Let Z denote the time between arrivals, i.e. Z = time B arrives – time A arrives (can be negative!).
(a) What is the range of values of Z (i.e Im(Z))?
(b) Find the density of Z (derive a formula similar to the convolution formula derived in class).

The Solution

(a) The times for Z can vary from -10 to 10. Suppose friend A arrives at 6:55 and friend B arrives at 7:05. Z would = -10. The other way around will result in Z = 10
(b)

Define Random Variables

X = # of minutes (continuous) after 6:55 friend A arrives
Y = # of minutes (continuous) after 6:55 friend B arrives

Outline of Problem

• The probability distribution functions of X and Y are uniform (constant and area = 1)
• The convolution of the pdf’s of X and the negative of Y (X-Y) equal the pdf of Z
• The result should look closer to the normal curve because of the Central Limit Theorem

The two input pdf’s and the result of the convolution which is the pdf of Z

Performing the convolution

Note: a=10

Simulation

• Random number generator is a uniform distribution
• Histogram of Randbetween(0,10)-Randbetween(0,10) 2092 times divided by 2092
• Discrete version of this problem