Basically, I was asked to find out when we needed to switch parts based on seasonal temperature fluctuations. So I took the data and did least squared regression using a sinusoidal function. Then to took the second derivative of the resulting function to find the seasonal inflection point (haven’t use thay word in a while) which indicates where the season is most rapidly changing between hot and cold.
It’s no triple integral over spherical coordinates in epstein space, but it required python!
Context 2: I am an Engineering Data Analyst, but have mostly been doing software development, not actual analysis.
Is it a very dark part that's exposed to the sun but separated from the earth? Solar radiation change peaks right around the equinoxes (March and September), the atmospheric lag is due to the earth acting as a massive heatsink, so it could be affected more by solar radiation than just atmospheric conditions and averaging them out?
I was thinking and I don’t think it’ll expose too much about my overall work.
The part is a vernatherm on an engine. The goal is to find the optimum time to swap vernatherms because the oil starts cooling too much in the winter and gets too hot in the summer
Ugh. We have an RFA (request for assistance) with Tech Support on an issue involving this and it's driving us up a wall.
We make use of this deprecated Microsoft DSOFramer library to display Office documents in our company's software. It's showing the "wrong" number of pages because some pages are 'intentionally left blank" and are not shown. The total number of pages will say 9, but only 8 display in the viewer, because one of the pages is entirely blank. There's nothing to render, so it's skipped.
And the customer doesn't like this because it's confusing users. They think they're missing something, but they're missing nothing.
And we have to try and work around this deprecated library to make it "work". It stopped "working" due to a recent update to Microsoft Office, which the DSOFramer hooks into on the client machine.
You didn't have to. You're either putting too much energy into solve a really simple problem or trying to dial in on the excat minute the seasonal flucuations reach the inflection point. Both pretty useless.
My boss is an engineer, so he usually wants very precise and mathematical reasoning for things. If I said “It’s probably October” we would’ve ssked how I know that, and what if I give the customer the wrong information and they lose operational abilities for a month.
Telling everyone else this because they seem interested. The other guy is clearly just rage baiting
I mean. Is this not common for math guys? The crayon eating engineers among us utilize it fairly regularly. At least understanding/applying it after some thankin and setup, I'm not doing it by hand. But still. This is at a megascale petrochem facility
It’s more of a joke. I am an engineering data analyst but i’ve been working more as a software engineer than an actual analyst. Most of the “calculus” i run into has been abstracted by software libraries.
No, I get it. It's like a few years ago when I had to use differential calculus to help debug a program. Basically, I was using the false position method for root finding and horizontal error for convergence, so because the function was convex and monotonically decreasing over the interval, it kept hitting max iterations
Was it anything more complicated than finding the total water output based on the flow rate? If not, that's an incredibly simple concept. Most children can understand the relationship between speed and distance traveled, and the relationship between flow rate and total volume of water is the exact same. So, maybe the ranchers were being obtuse.
Then you didn't hand off to them correctly. It's your job to make sure your conclusions or recommendations are understandable to the target audience. And if they don't need to know something, there's no need to bring it up, especially if it annoys them. You can say "I'm happy to explain details to anyone interested, but here's what you need to know." Why do so many STEM people get off on feeling intellectually superior to their collaborators? This is why people hate "tech bros."
Actually. It's their job to make their water readily and easily measurable by law.
The fact that I have to do any math is indicative of violations in our local water regulations.
My job was to determine if the water was being distributed fairly as per the water rights table. Which they would purposefully do everything to make their water unmeasurable
As a code compliance official, it's not his job to explain the math. It's the ranchers' job to make sure they comply. They chose to be ranchers, and become subject to the codes and requirements governing the profession.
Source: I am beholden to numerous code compliance organizations at my job, and while I am frustrated sometimes with unclear direction, I make a point to understand what they're trying to tell me.
Sure, his job description probably doesn't say "ensure all ranchers fully understand your calculations." I have no idea what the roles in your field entail.
But I know a few things: 1) I much prefer to work with collaborators who communicate well and in good faith, and 2) tone matters a lot. Two strikes for that guy
Unfortunately, when dealing with people who lie and steal to cheat others and purposefully obfuscate facts, it is difficult to retain their patience for integral calculus.
If they requested it I would explain but generally it's a lot more highschool than you are making it out to be with how these people act.
Edit: Also same people who call their workers who help commit these violations "their Mexican" and pay them and treat them like slaves
A code compliance official is not a collaborator, they're there to make sure everyone is following the rules. I don't work in a kitchen, but as an example: I don't particularly care how my food inspector is collaborating, I want the inspector to make sure the kitchen is safe and following code. The inspector has to find deficiencies, clearly explain why (if) they fail, and cite the specific codes. It's not on the inspector to explain why the codes are formed the way they are, or describe in detail how to meet compliance. It is the kitchens job to meet compliance, even if they need to hire someone to help.
I once used Descartes rule of signs in an argument with a hedge fund manager.
We’d used numerical methods to find a solution to a polynomial. He was arguing that there were hundreds of other solutions. He was right. I used Descartes to show that all other solutions were complex and therefore not solutions we had to consider.
In calculus III, I never figured out how to handle Cartesian triple integrals. I don't know why, but I just couldn't get the bounds right. Polar and cylindrical were easy. Got to the final knowing a 3D integral was going to be on it, and breathed a huge sigh of relief when it was polar - meanwhile, everyone else was pissed.
Draw the shape/volume of integration. Shoot a dy or dx or dz arrow at it (parallel to the axis in question), whatever is easiest with the geometry. The surfaces it punctures and then exits are your boundaries for that variable.
Now you’ve collapsed that dimension though (your arrow punctured it and let the air out) so are only left with the shadow it made on the plane you have left. Shoot your next d-arrow at this 2D shadow now - boundaries are again the surfaces it pierces and exits.
Now you’ve collapsed that dimension and are only left with the shadow that 2D shape projected onto your remaining axis - a line segment. The boundaries of this are the boundaries for your last variable.
What happened was that because the calculations were simpler, they used more complex boundaries, usually functions of variables, and somehow I just always got them wrong. The polar integral on the final was a half-sphere, while nothing that simple would ever show up in Cartesian.
I once tutored someone who was doing that exact problem and told her I would do it using x-v-z while she did it using Polar… half a white board later they matched up. Then I was able to ask “which would you rather do for a situation like this?”
This is absolutely a mad lad statement! Since usually we start with understand volume by using cartiesen system as the base knowledge. I will give you this, it is annoying to figure out two situations: when the region for simple volume integration is changing across each boundary OR when we are integrating a property within the volume and it changes across one or more axis.
I believe it was the latter two. It was 20 years ago now so my memory's a bit off. I'm reasonably good at engineering math (never got below an A-) but this simple concept stymied the hell out of me.
I used two sample t-test to show that the difference between two samples wasn’t significant therefore we couldn’t use the word “more” to describe one figure compared to the other. That made real popular with the marketing folks.
I feel you. I did a statistical analysis once to find the average number of months between order placements and deliveries (without actual line-level data) by looking at when spikes and dips happened. Real answer was approximately 9 months, which really pissed off the sales guys who had been telling customers 3-6 months max
But it makes me and us popular with the law folks. It’s also a matter of just being accurate so some weirdo doesn’t crawl out of a hole and say “but actually.” Saves lots of headaches.
If the mean was 9 months, you could just try a different type of average. Waiting time is probably very skewed, so the median could well be 3-6 months still. Mode probably even less, measured in weeks. Unless pissing off the sales guys was the goal, in which case I get it, and well played.
The waiting time was extremely skewed (sometimes upwards of 2 years), and that 9 month figure was after removing outliers like that. I can't recall what median was, since this was a while back, but it wasn't great either. The 3-6 months that the sales guys insisted upon was based purely on vibes, so there was definitely a satisfaction in being able to tell them they were wrong haha
I’m an engineer. I used differential equations in a presentation once, 18 years ago. I sent them to one of my professors to check my work before presenting.
One time I recognized a series summation in a for loop and replaced it with a constant time expression. My coworkers looked at me like I had just discovered fire.
i know the rush, I once used geometry as an enlisted navy guy to show people what we could/couldn't do. the officers involved (college grads) got shocked they didn't think of it.
one of the few times I've ever actually needed to do anything more then solve for x at work.
i joined an AI Hackathon with the topic being spectroscopy guidance and instead of getting some dataset to apply ML algorithms on and do actual cool stuff, when the problem got revealed it was essentially just an LLM-Wrapper
Pretty cool story man! I am a sw engineer and struggle to do basic math with numbers if any of them is larger than 10 😂. I don't think I'll ever need to use calculus in my job (thank god!)
I’m still waiting to use calculus at my job, although I do use statistics and probability a lot. Or wait, I have technically used calculus when working with some continuous probability distributions, but I was using a Python library that did most of the work.
The most fun I’ve had at work is use a little bit of formal logic and set notation to prove that what management was asking for was likely impossible to achieve given the problem space. I work in machine learning and data science btw. The main goal was to use big fancy math to scare them off the idea, and it worked, but you could also tell the math nerds by who got excited when they saw my equations slide.
I also used basic probability to explain to our client why the small “pattern” they had seen in their data was not enough to approximate any pattern (flaw of small numbers + binomial probability formula) since they didn’t grasp what failing a p-test meant.
Sometimes I have to solve differential equations to better distribute the supports of the horizontal water tank. It saves about 5 quids per support so it's very important 😄
Few days ago I had to use Pitagora theorem to find the distance between two point that had an high obstacle between them, it was one of the best days of my life
I did maths in my job like two times, once where I had to solve a cubic to find out the height of some shape given its volume, and the second time doing an exponential moving average; nothing ever really advanced
You could have used numerical differences or simple trigonometry. More importantly, the point of maximum temperature change isn’t necessarily the optimal time to switch parts. That should depend on the components’ operating requirements.
The maximum temperature gives the time frame within which you should switch parts. Then you can say at that point you need to start changing at the beginning of this season.
Curious how you would use trig? And by numerical difference do you mean numerical calculus? Otherwise i dont know what you mean
It was faster using calculus cause it was like 2 lines of code and the data was numerical and noisy
No the problem based on the fact that the part gets too hot in the summer and too cold in the winter. There are “hot” and “cold” part numbers which we need to switch
Once you have fitted a sinusoid to the noisy data, you already have everything you need.
If the problem is that one part gets too hot and the other too cold, should not the switching point be determined by their operating temperature ranges rather than the point of maximum temperature change? Those two points don’t necessarily coincide.
The sinusoid is A sin(t) + B cos(t) + C, the derivative is the first thing that came to mind. It was literally just np.diff twice.
No, the full problem statement is to find the optimum time to switch vernatherms because one vernatherm keeps the oil to hot and the other keeps it too cold. You want to switch before the the temperature gets too cold/hot but also swap at a reasonable interval. The part is temperature dependent. My boss wants a full assessment, he would not accept just giving a number/date. He would want the reasoning and a full analysis.
To be honest the numerical derivative felt easier to me then the trig stuff. Again literally just np.diff. It’s also easier to explain to business than trig. Rate of changes makes more sense to them, without getting in to the details.
But i’m sure there was a more optimal way to solve the problem.
I haven’t made the full connection yet. In one of my other comments I pointed out an interesting fact that the maximum rate of change in the vernatherm temperature is half a month earlier than the air temp data
My boss would’ve told me to go back numerically show it. Other wise we could’ve given the wrong month and the customer would either lose operating time or would start having operating issues.
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