text:
Publication

# Lattice swelling and modulus change in a helium-implanted tungsten alloy: X-ray micro-diffraction, surface acoustic wave measurements, and multiscale modelling

### Authors

Hoffmann, F.; Nguyen-Manh, D.; Gilbert, M.; Beck, C.; Eliason, J.; Maznev, A.; Liu, W.; Armstrong, D. ; Nelson, K.; Dudarev, S.

### Abstract

Using X-ray micro-diffraction and surface acoustic wave spectroscopy, we measure lattice swelling and elastic modulus changes in aW-1% Re alloy after implantation with 3110 appm of helium. An observed lattice expansion of a fraction of a per cent gives rise to an order of magnitude larger reduction in the surface acoustic wave velocity. A multiscale model, combining elasticity and density functional theory, is applied to the interpretation of observations. The measured lattice swelling is consistent with the relaxation volume of self-interstitial and helium-filled vacancy defects that dominate the helium-implanted material microstructure. Larger scale atomistic simulations using an empirical potential confirm the findings of the elasticity and density functional theory model for swelling. The reduction of surface acoustic wave velocity predicted by density functional theory calculations agrees remarkably well with experimental observations.

XSD

2015

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## Mind Over Machine331

Posted by michael
from the ultimate-laziness dept.
broKenfoLd writes "Monkeys moving robotic arms by manipulating a cursor on a computer screen, simply by thinking about it? Mice who cause their water tube to dispense some refreshing H2O just by wishing it? Signal processing and decoding has long been a dream of Matrix fans and lazy system administrators for years, and science is amazingly keeping up! Popular Science's Carl Zimmer has written a fascinating piece documenting recent progress in decoding brain signals and interpreting commands issued from thoughts alone. If you heard a single violin playing Beethoven's 5th, you would be able to tell what piece of music was being played even though the rest of the orchestra was not heard. In the same way, by monitoring a relatively few neurons, computers can recognize patterns and allow programming based on these patterns to say, know if a mouse is thinking about pushing his water lever. You can pass the time waiting for Matrix-style video games and motionless system adminstration/utilization by reading the full article."
This discussion has been archived. No new comments can be posted.

## Mind Over Machine

• #### Channel surfing (Score:5, Funny)

on Friday February 27, 2004 @02:21PM (#8409970)
But can it be used for channel surfing. That's the ultimate goal.
• #### Re:Channel surfing (Score:3, Interesting)

How do synapses encode the need for pr0n or cartoons? That's really the question.
• #### Re:Channel surfing (Score:3, Funny)

but the TV would be stuck on the p0rn channel. if you've got a wife, LOOK OUT!!
• #### Re:Channel surfing (Score:5, Funny)

on Friday February 27, 2004 @02:48PM (#8410278) Homepage
but the TV would be stuck on the p0rn channel. if you've got a wife, LOOK OUT!!

The trick is to marry someone who enjoys watching porn with you. It's not that hard; if I can do it, anyone can.
• #### Re:Channel surfing (Score:5, Funny)

on Friday February 27, 2004 @03:08PM (#8410472)
What's his name?
• #### Re:Channel surfing (Score:5, Funny)

<tanguyr+slashdot@gmail.com> on Friday February 27, 2004 @03:19PM (#8410598) Homepage
i'm thinking real hard of modding you +1 funny. let me know how it works out.
• #### Something's wrong (Score:4, Funny)

on Friday February 27, 2004 @05:06PM (#8411703)
It's not that hard

Then what's the point? Especially when married?
• #### Re:Channel surfing (Score:3, Funny)

Please. This is /. The only wives we have are from here. [realdoll.com]
• #### Re:Channel surfing (Score:2, Funny)

Here I though the idea was to make it possible to force 1000 monkeys to type more continuously.

We have got to see if Shakespear was better than 1000 monkeys don't we?
• #### Useful... (Score:2, Funny)

computers can recognize patterns and allow programming based on these patterns to say, know if a mouse is thinking about pushing his water lever.

Sounds like an old joke we shared around the IT dept about 20 years ago related to 'anticipatory paging', why not anticipatory programming. Hmm. Useful

This could save some of the

effort [umd.edu] of heavy lifting of that axe or driving that nail.

"after the nth time the process failed I gave the computer such a look that the software uninstalled itself, the harddrive cra

• #### Re:Useful... (Score:3, Funny)

why not anticipatory programming

THEN x = 3
IF x == uninitializedValue
• #### Re:Useful... (Score:3, Interesting)

You think it's funny, but that's how you actually program in a stack-based language (Forth, Postscript, ...).
• #### Just don't forget one thing! (Score:5, Funny)

on Friday February 27, 2004 @02:23PM (#8409989) Journal
Monsters, John! Monsters... from the id!
• #### This was on HDNet via DirectV (Score:4, Interesting)

on Friday February 27, 2004 @02:23PM (#8409990)
Saw this on HDNet... very very very cool..
I esp like the lady with the leads out of both sides of the back of her head....

She looked very Borg-Like.
• #### This could be bad... (Score:5, Funny)

on Friday February 27, 2004 @02:23PM (#8409991) Homepage

Can you imagine what might happen when a "hottie" walks though the office?

• #### Re:This could be bad... (Score:5, Interesting)

<jotaigna@yahoo.com> on Friday February 27, 2004 @02:29PM (#8410075) Homepage Journal
I remember a scene from "Macross Plus" Where two batteloids where flying and one of them was "neuro controlled". In a part, the neurocontrolled batteloid falls very fast and the other batteloid saves it from crushing into the ground, but as the "neuro" pilot regains control of his mecha, he wishes the other pilot was down(there is some grudge between pilots) and inmediately the mecha obeys the wish and wrecks the old batteloid!!. Be carful of what you wish, if you are hooked to a machine, you might get it!.
• #### Re:This could be bad... (Score:5, Funny)

on Friday February 27, 2004 @02:30PM (#8410081)
all the CD drives prematurely eject?
• #### Re:This could be bad... (Score:3, Funny)

Can you imagine what might happen when a "hottie" walks though the office?

• #### Re:This could be bad... (Score:3, Funny)

So that explains all that spam! Wait, I can't feel the wires. They must have used wireless devices! Help, I'm not sure if this is really me!
• #### Re:This could be bad... (Score:5, Funny)

on Friday February 27, 2004 @02:36PM (#8410155)

Interesting question. I love questions like this that we can debate, secure in the knowledge that we will never find out the real answer. Eventually we will find out what it is like to have this working, but we geeks will never find out what it is like to have a "hottie" walk though the office.

Congratulations, you have posed the perfect open ended question.

• #### Re:This could be bad... (Score:5, Funny)

on Friday February 27, 2004 @02:59PM (#8410380)
ahhh.... you obviously have never worked on the same floor as HR. ;)
• #### Re:This could be bad... (Score:5, Interesting)

on Friday February 27, 2004 @02:48PM (#8410279) Homepage Journal
Funny but if something did happen, the system would be a failure.

When you "think" about doing something, you are deciding via pros and cons, deciding outcome, looking at all options, recounting experience, true desire... on wether to do something or not. When you really decide to act, you act. That signal to act causes you to act. Thinking about acting is not acting. The final go ahead trigger to act is what matters. How else could you make a logical decision about anything? If you take out the thought process involved, we all would be living in a completely different world.

Consider the mouse and the bottle. If the mouse really wanted to get a drink, he would go over and get one. It's not like some force is holding him back and he keeps thinking about it but he just (slow superhero struggling voice) can't moooooooove.
• #### Re:This could be bad... (Score:3, Insightful)

Consider the mouse and the bottle. If the mouse really wanted to get a drink, he would go over and get one. It's not like some force is holding him back and he keeps thinking about it but he just (slow superhero struggling voice) can't moooooooove.

Hahaha. You're absolutely right.

Now, enough /. I've got things to do. ... rrrrhhhhhhaaaaaa... ok, well maybe just a little more.
• #### Re:This could be bad... (Score:3, Insightful)

well, yeah, but what's the difference between the signal that makes you want to move your arm and the signal that actually does it? the monkeys learn that they get the desired response by just sending the "intent to move arm" signal instead of the whole "activate arm muscles" signal.
• #### We have that already. (Score:5, Funny)

on Friday February 27, 2004 @02:23PM (#8409992)

I call it sleeping.

• #### Re:We have that already. (Score:3, Funny)

I call it working for a government agency. (Before you accuse me of trolling, I am working for a government agency.)
• #### Not such a big deal (Score:5, Funny)

by Anonymous Coward on Friday February 27, 2004 @02:23PM (#8409993)
My water tube can dispense a refreshing H20-based substance just by wishing.
• #### Say it all with me now... (Score:5, Interesting)

<skennedy@nOspAm.tpno-co.org> on Friday February 27, 2004 @02:23PM (#8409995) Homepage
...this is some neat shit.

What other computer do you know can learn how to use foriegn devices without a driver disk? :)
• #### Re:Say it all with me now... (Score:5, Funny)

on Friday February 27, 2004 @02:30PM (#8410080)
The best part is that this computer can be mass produced with unskilled labor!
• #### umm.. not just yet. (Score:5, Interesting)

on Friday February 27, 2004 @02:24PM (#8410011) Homepage
the best of these kind of devices (devloped in nasa labs) can only do 95% accuracy. sure that might be fine for say playing a video game(unless its fast pace), but if you tried to walk with 95% accuracy, you'd be the but of more jokes then the "how do you get bob dole out of a tree, wave to him" jokes.

but over all its really cool that they are even able to do this at all.
• #### Re:umm.. not just yet. (Score:3, Insightful)

Even in a fast paced video game, how accurate are you with a mouse? Especially after all the sugar/caffeine? 95% is astounding.
• #### Re:umm.. not just yet. (Score:5, Funny)

on Friday February 27, 2004 @02:31PM (#8410100) Homepage Journal
"but if you tried to walk with 95% accuracy"

95% is better than me and my friends after a night out onthe town and we make it home ok. 95% is pretty good betting odds, too.
• #### Re:umm.. not just yet. (Score:2, Funny)

the best of these kind of devices (devloped in nasa labs) can only do 95% accuracy.

Well, so they claim, it's a robot that just appeared one day and keeps complaining about this horrible pain in all the diodes down its left side.

• #### Wow, Me Too! (Score:5, Funny)

on Friday February 27, 2004 @02:25PM (#8410024)

"Mice who cause their water tube to dispense some refreshing H2O just by wishing it?"

Uncanny! Just this morning I caused by "water tube" to dispense liquid just by wishing it too!

• #### Thinking... (Score:2, Interesting)

Printing out poster-sized Pr0n just by visualizing it?

Everybody... The day is now!!!

• #### Cell Phone (Score:5, Insightful)

on Friday February 27, 2004 @02:26PM (#8410030) Homepage
It would be interesting to have a cell-phone implant. You can call your friends and relatives, and always get them and know what they are thinking. And MAN, it would get annoying!

How about living in a way that our bodies were actually meant to. Exercising, working with our bodies, and communicating in person. Eventually we will just be sitting at home, in a lazy-boy with our brains plugged in to a network and all work from home. But, that would suck!

• #### Re:Cell Phone (Score:5, Interesting)

on Friday February 27, 2004 @02:36PM (#8410156) Journal
If you read 'The Light of Other Days' by Arthur C Clarke & Stephen Baxter you'll get a good insight into the possible consequences. While the book is centred around the idea that wormholes can be used to view anyone at any time, knowing what people think would have the same effect of first causing terrible unrest but eventually destroying barriers and allowing everyone to work together. It's a very interesting read and I feel that every day we get closer to that reality.
• #### Re:Cell Phone (Score:5, Interesting)

on Friday February 27, 2004 @04:55PM (#8411610) Homepage
While the book is centred around the idea that wormholes can be used to view anyone at any time, knowing what people think would have the same effect of first causing terrible unrest but eventually destroying barriers and allowing everyone to work together.

Every action being publicly known would cause you to think through everything you do. Every thought being public would cause you to fear thinking too much - about ideas that might be too controversial, sexual fantasies you might want to indulge in, feelings of hatred and hurt towards someone and so on. If your thoughts take you too far, perhaps you'll be an Enemy of the People(TM).

I don't think it'll be a better world. I think peer pressure and desire of conformity would mold people into the same shape, strangling creativity, initiative and independent thought. Not to mention what sects and such could do - brainwash initiates until they too are true believers.

The only way it would be a good idea is if you could directly point to an action it would cause, in order to prevent it from happening - much like Minority Report. But the film convieniently circumvents the issue since they see nothing but thoughts that do result in murder.

What if instead, they would have to monitor every thought, destroy all privacy, and couldn't tell if a perpetrator really would go through with it until the very last second? To intervene at the mere thought of committing a crime? That's the thing about thought crime - if you want it undone, it is undone. If you no longer want to kill the guy, well then it simply hasn't happened and won't happen. And the mere thought of it, I think everyone is guilty of - if even for just a flash.

Kjella
• #### Re:Cell Phone (Score:3, Insightful)

How about just implanting the ringer, so they don't bother the rest of us?
• #### Re:Cell Phone (Score:3, Funny)

Well, there is pre-speech thought and there is conceptual thought. Aside from sounding like a jumblefuck of absolute nonsense, if any conceptual thought slipped into your little mental cellphone, you might have some trouble on your hands.

"No mom, I haven't filled out the job application yet!fuckingshitfilledpieceofdeathuselesskillhatri d noneedjobgetweedsmoke"

"What the HELL was that you were thinking?!"

"Umm.. ahh, I think the electrodes are malfunctioning... wait... uhh, hold on, you're breaking u
• #### Re:Cell Phone (Score:5, Insightful)

on Friday February 27, 2004 @05:03PM (#8411680)
How about living in a way that our bodies were actually meant to. Exercising, working with our bodies, and communicating in person.

What about the idea that humans were "meant to" improve themselves technologically? Check out the book "Natural Born Cyborgs" [amazon.com] by Andy Clark -- he makes a pretty convincing argument that things like cellphone implants or robotic limbs aren't a bizarre aberration. Rather, they're incremental steps on the long road of technological self-enhancements that started the first time someone used the technology of writing to remember a piece of abstract information the unaided brain would have forgotten.

Even if you reject that argument, you have to figure out where to draw the line, and the answer isn't at all obvious. Were humans meant to see fine details on objects miles away? Toss out those binoculars. Were we meant to instantly kill other creatures without laying a finger on them? Forget your rough-hewn spearheads and boar traps, if not. Were we meant to survive heart failure? (Careful that your reasoning doesn't also conclude that gene therapy to live for 1000 years is fine too, if you want to be traditional but still humane.) To travel halfway around the globe in a matter of hours? To walk on the moon? The list goes on.

Humans are naturally unnatural. It's what makes us what we are.

• #### Re:Cell Phone (Score:3, Interesting)

Humans are naturally unnatural. It's what makes us what we are.

Granted. But one question is, will this continue to serve us well in future, or should we recognize that as our technology advances, we may need to become more careful about the kinds of unnatural things we do, and become dependent on? Might we end up self-modifying our species into something weaker, in some crucial respect, than what natural evolution gave us for free?

What the species as a whole does blindly may not be the right choice

• #### Re:Cell Phone (Score:3, Insightful)

How about living in a way that our bodies were actually meant to.

Meant to? Meant to by whom?
• #### But what if I didn't like my neighbour? (Score:5, Interesting)

on Friday February 27, 2004 @02:26PM (#8410041)
And I ran him over with my SCV?

"I didn't run him over!"
"Did you THINK about running him over?"

*long pause*

I didn't run him over!
• #### Ok, that should be SUV... (Score:2, Funny)

Not SCV...Damn Starcraft.
• #### ai (Score:2, Funny)

They're talking about reverse engineering the brain - it would be pretty sweet, but one hell of a task to filter through all the activity and figure out what signal meant what, combinations, etc. I'm sure an Altair is all you would need to reverse engineer my brain. You'd flip maybe ten switches, tops.

• #### Average Person (Score:3, Insightful)

So, the average person thinks of sex like every 4 seconds. The traffic on one of these brain networks would have more porn than the internet.
• #### I don't think it will ever be like in the movies (Score:5, Interesting)

by Anonymous Coward on Friday February 27, 2004 @02:29PM (#8410073)
I mean, the rat can think about water, and get some water. But a rat's mind is way simpler.

Have you ever thought about suicide? Now imagine if when you thought about it a machine would come and kill you. Also I don't know about you, but I can't control my mind completely, sometimes I have thoughts that are completely unrelated with what I am doing... I really don't think I could trust a machine to make my thoughts come true, I'm sure in the future machines will be able to interpret the signals in your brain with a 99% precision, I just can't trust my own mind.
• #### Re:I don't think it will ever be like in the movie (Score:5, Funny)

on Friday February 27, 2004 @02:47PM (#8410269)
But a rat's mind is way simpler.

Allow me to introduce you to our management team.

KFG
• #### oh no (Score:5, Interesting)

on Friday February 27, 2004 @02:29PM (#8410074) Homepage Journal
If we can control the machines, can someone else come back through the machine an control me??? Could I be hacked??? Would I have to have a firewall in my head???
• #### got the show for you... (Score:3, Interesting)

It's called "Ghost in the Shell" and discusses issues like this (it's an anime BTW). In the case of the article, though, there isn't any feedback or direct neural stimulation, so now you couldn't be hacked.
• #### Shoulda seen this (Score:4, Informative)

by Anonymous Coward on Friday February 27, 2004 @02:29PM (#8410076)

Brain-Computer Interfaces for Communication and Control [sfn.org] at the society for neuroscience annual meeting. There are already paralyzed people using this type of technology (electrode and even EEG(!)) on an experimental basis.

• #### A step to the singularity (Score:2, Interesting)

Now it's reading the brain. But eventually it will be reading a deeper part of the brain, and not needing the rest of it.
• #### Maybe in the future... (Score:5, Funny)

on Friday February 27, 2004 @02:30PM (#8410086)
...we'll be able to RTFA just by thinking about it!

But that would require thinking, and that hurts :(

• #### Re:Maybe in the future... (Score:2)

If we all were able to RTFA just with a thought not even yahoo could handle the /. effect.
• #### This journal.... (Score:5, Insightful)

on Friday February 27, 2004 @02:32PM (#8410108) Journal
Popular Science, ya gotta luv'em. I just wish the track record was a bit better, after reading about the nextgen dirigibles off and on for years I'm just a bit disapointed, that sounded like so much fun. Probe in my head? Less so.

Mod me down, off topic troll ;-) but still...
• #### What about the reverse...? (Score:5, Interesting)

<(moc.liamg) (ta) (grebrho.kcim)> on Friday February 27, 2004 @02:32PM (#8410109) Homepage Journal
This could have a potentially incredible impact on impaired and disabled people. Imagine if Stephen Hawking would be able to work at the same speed his mind seems to function at? However, what about Mind through Machine over Mind [go.com]? Put your helmet on, jack in, and remote control that fish - imagine the long-time deep-sea discoveries we could make - maybe even find a live Architeuthis [mus.pa.us]?
• #### I'm thinking... (Score:2, Funny)

1. I'm thinking to secure the server/firewall/whatever... Zzzzzt! done!

2. I'm thinking I deserve a raise. Zzzzt! agreed.

Idiot! 3. I'm thinking I'll have myself a raise. Zzzzt... done.

4. I'm thinking that the leggy busty blonde wants visit my bed tonite...Zzzzt!

5. I'm thinking I should you all leave think. Zzzzt!.. !@#RTA [NO CARRIER]

• #### This is all cool, but... (Score:5, Interesting)

on Friday February 27, 2004 @02:36PM (#8410159) Homepage
This does not answer how brain works at all :-) As a motor control neuroscientist by trade, I can tell that finding out what the brain actually doing has little to do with these neat things.

This is not to say that it's not important -- all kinds of prosthetic devices can be made to help people with disabled limbs or other parts of the motor control system -- so it's a great benefit to those people. The important thing is that these devices are still controlled by the human brain, and nobody has a good idea how.

The fact is, you can probably hook up whatever device to whatever portion of the brain (e.g. an artificial arm to you toenail brain area) and after some practice the subject will learn now to move it. So when they say "we don't see the brain as a mysterious organ anymore" they are telling you a bold-face lie.

The mystery would be demonstrated to be solved when we can build a computer with massively parallel and slow (up to 1kHz) elements that can match human performance in tasks like tracking, reaching, as well as learning those tasks.

So far, all the beatiful performance of the cool gadgets is accomplished by super-fast feedback and super-fast computing elements. Our neurons are ways slower, but they do much better. Therefore, the whole essense and mystery of the brain is how to connect 10^10 shitty elements into a great learnable machine. Algorythms and parallelism are still the mystery of the brain, even if the popular science magazines claim otherwise :-)
• #### Re:This is all cool, but... (Score:5, Insightful)

<<moc.yggorhp> <ta> <3todhsals>> on Friday February 27, 2004 @02:49PM (#8410288) Homepage
The fact is, you can probably hook up whatever device to whatever portion of the brain (e.g. an artificial arm to you toenail brain area) and after some practice the subject will learn now to move it. So when they say "we don't see the brain as a mysterious organ anymore" they are telling you a bold-face lie.

Does the mouse get water by thinking about water, or by thinking something completely different that happens to trigger the machine? Once he figures it out, he'll do it again when he's thirsty.
• #### Mind Wide Open (Score:5, Informative)

on Friday February 27, 2004 @02:36PM (#8410160)
NPR has an interesting interview with Steven Johnson, author of Mind Wide Open: Your Brain and the Neuroscience of Everyday Life [npr.org] . One segment talks about manipulating on-screen animations with Alpha brainwaves, to retrain people with ADD how to focus.

• #### Thought Power (Score:2, Interesting)

Still waiting for the implantable math co-processor, ideally with optically interfaced plotting/visualization capability ...

Imagine the possibilities.
• #### I Wish (Score:2, Funny)

Singing to self: "I wish I was an Oscar Myers wiener"

P O O F !
• #### Controlling your computer by thought: could be bad (Score:4, Interesting)

on Friday February 27, 2004 @02:41PM (#8410211)
It could be bad to be able to control your computer by thinking. Just imagine if you were sitting at your thought controlled computer when a "friend" comes up and asks, "hey, what's the command to delete everything recursively without confirmation?"

Then, before you know it, you've thought, "\rm -r *"

Okay, I saw something like this (minus the thought part) happen in real life once upon a time. A friend and I were just talking about people accidentally typing "\rm -r *" in the lab when suddenly, someone using the Sun boxes yelled "oh shit!" because he absentmindedly typed what we said.

• #### Re:Controlling your computer by thought: could be (Score:3, Interesting)

Better yet, what happens when you feel like destroying the computer. Will it self destruct, or act in self defense?
• #### I don't understand something... (Score:5, Insightful)

on Friday February 27, 2004 @02:45PM (#8410251)
They talk about using this for people with disabilities. This would be great for sure but
they say in the article that they need to "train" the computer beforehand (no pun intended)
before it can ... interpret though.

My question, which was not answered in the article, is: Are every brain emmitting the same signals for the same action
or do they need to "train" the program for every new user (monkey)? I would think that every individual have a somewhat
unique "brain signature" and if it is the case, how can a totally impaired person train a computer to use an artificial arm or
leg or whatever if anyway he isn't able to move a "joystick"?

Can the computer associated anything as an input to compare with the brain activity?
Could (let's say ) S. Hawking program the system by blowing in a tube harder or smoother for example?

Am I clear? ;-)
• #### As his cat goes up in flames... (Score:3, Funny)

on Friday February 27, 2004 @02:51PM (#8410307)
As his cat goes up in flames...

No!!! God dammit!!! I thought a BUD LIGHT!!!
• #### Mana From Heaven. (Score:3, Interesting)

on Friday February 27, 2004 @02:52PM (#8410314) Homepage
This sort of reminds me of Ursula K. Le Guin's story, "The Lathe of Heaven". For the uninitiated, "The Lathe of Heaven" takes place in Portland, Oregon in the year 2002. Its main character, an insignificant working class man named George Orr (Bruce Davison who appears in "The X-Men" movie), is plagued by 'effective dreaming', where his dreams literally come true.
• #### I'm thinking of.... (Score:5, Funny)

on Friday February 27, 2004 @02:52PM (#8410315) Journal
FIRST POST! FIRST POST!

(Damn, didn't work)

Natalie Portman in my cube.

(Nope, still doesn't work)

I want to be overworked and overpaid, but still have time to surf slashdot from work.

(Woohoo! It works!)
• #### Coding dream (Score:5, Interesting)

on Friday February 27, 2004 @02:54PM (#8410328) Homepage
I'm sure most coders out there have dreamed of this ability for years. No more clunky keyboard interface to slow you down.

Typos would be a thing of the past. Imagine scanning though some source and noticing that you assigned 100 to a var rather than 10, before you can even refocus your eye on the line the value has been changed.

Grep would be a thing of the past! Need to change all the instances of a function name? Think it and its done.

I want to be the lawnmower man!
• #### i am a bipedal broadcast station (Score:3, Interesting)

<moc.liamg' ta' `etirwerw'> on Friday February 27, 2004 @02:55PM (#8410336) Journal
Just another bipedal bag of mineral salts and trace elements capable of complex EMF broadcasting at low-range, subtle super-conduction at room temperature, and high-voltage carpet-capacitance pitching in my 2 coppers here...

Look developers, just get speech recognition running already, willya? If what your software does to my luminous eloquence is any example of the current state of interface tech, that thinking-cap UI is going to lead to some pretty psychedelic dyslexic synaesthesia in photoshop once it gets that olfactory plugin I've been waiting for...

• #### long term failure should be expected ? (Score:3, Interesting)

on Friday February 27, 2004 @02:59PM (#8410387)
computers can recognize patterns and allow programming based on these patterns to say, know if a mouse is thinking about pushing his water lever.
what would happen to the mouse if, at long term, she knows that by thinking about pushing the lever she don't have to push that lever anymore, the computer can't find that previous pattern because the mice have forgotten the use of the lever. thus reprogramming is re-required. seems like an infinite loop ...
• #### the exciting part (Score:5, Insightful)

by Anonymous Coward on Friday February 27, 2004 @03:13PM (#8410509)
The real exciting part isn't about the machine learning what the brain is doing, but rather the brain learning how the machine works. Near the end of the article, he talks about a cluster of neurons that grew in the monkey brains after the implants, and would fire only when the implants were active. The monkey's brain, in effect, sensed a new presence and adapted to it within minutes of its arrival.

If you've ever tried learning an activity that instinctive reflexes like skateboarding or ice skating or even playing the piano, you realize that no matter how much instruction someone gives you, at some point you feel like once you've done it enough, you just "get it". It's the whole muscle memory thing, how your brain encounters something new and just adapts, learning exactly which neurons to fire at the right moments to get the desired affect. Seeing neuron's grow and cluster especially for the robot arm is indicative that the monkey's brain can assimilate the arm and treat it as a natural extension as opposed to a external tool with an awkward interface. In geekspeak, it's like a kernel that, on detecting a new device, can probe it, learn the API, and build its own device driver automatically, without ever knowing anything other than that it's something on the other end of a bus.

Extending that line of thought, who's to say that if the signal processing and classification algorithms advanced far enough to classify even our thoughts, our brains wouldn't be able to instinctively learn how the mind-readers worked and retaliate in return?
• #### A squid stole my spaceship. (Score:4, Interesting)

on Friday February 27, 2004 @04:05PM (#8411154) Journal

What this really opens up is the possibility of training animals to operate machinery. Imagine taking an aquatic animal (such as a dolphin) and using it (or its brain) as the central component in a spaceship autopilot.

By stimulating various parts of the brain (including pleasure centres), one could train it to respond to your input in the way you want - it already has the hardware to deal with three dimensional maneuvering, timing and calculating trajectories and intercepts.

This was used in a novel called Space, in which GM Squid controlled a space probe. In the novel, the squid became smart enough to do a runner with it.I would look up the author's name for you all, but try typing "Science Fiction" and "Space" into Google and see what happens ;)
• #### Is it time for ... ClippyXP? (Score:5, Funny)

on Friday February 27, 2004 @03:26PM (#8410692) Homepage Journal
"You are thinking of typing a letter ... "

Pleeeeeeease don't let MS get their hands on this one, mister!

• #### I thong ot well be cool! (Score:5, Funny)

on Friday February 27, 2004 @03:36PM (#8410818) Homepage
I can't waid two get this of my home computer. I hoop is works is goat as me speak recondition program!

-
• #### Where is all this going... (Score:3, Informative)

on Friday February 27, 2004 @03:44PM (#8410905)
Reading the article it occurred to me that in the future jobs may require that an employee get brain implants in order to perform some job related task or interact with future computer systems where manual user interface interaction is no longer practical. Would such systems separate workers into a group who are willing to submit to such an invasive operation and those who would refuse implants. I wonder how long we have before implant specifications start to appear on job descriptions and resumes?

The article did touch on the ethics of placing such implants into healthy soldiers, but ethics and morals that would prohibit such activity tend to be very fluid.

Non-invasive techniques may one day be developed for interacting with machines through thought, but this technology is probably much further off than taking the short-cut of hardwiring the brain.
• #### Chicken or Egg? (Score:4, Insightful)

on Friday February 27, 2004 @04:04PM (#8411144)
Does the water come when mice are thinking they want water...OR

have they learned that every time they think about death/sex/food the water comes?

• #### I was interested until I saw "Popular ..." (Score:4, Insightful)

on Friday February 27, 2004 @04:20PM (#8411310) Homepage
The same people who brought you "Nuclear, sorry, Nucular Cars," "Flying Cars," and what ever else doesn't require much imagination and even less knowledge of math and physics.

Entreprenurial posers.

Still it sells magazines.
• #### In my job, I practice with this everyday (Score:3, Funny)

by Anonymous Coward on Friday February 27, 2004 @05:06PM (#8411715)

Yip.
• #### What am I thinking? (Score:3, Insightful)

<baelzharon@gmai[ ]om ['l.c' in gap]> on Friday February 27, 2004 @05:31PM (#8411897)
What about the thoughts you "really" don't need everyone else to know hear though. Somehow it needs to determine what to transmit and what not to. Even if it is controlled by you thinking, 'say this or that', what if you're thinking of saying it but don't really want to. This is getting confusing. You could imagine thinking about talking and having it projected into a room 2,000 miles away," says Craig Henriquez. "I don't see that that will be a problem. It's very, very possible."
• #### Wrong focus? (Score:3, Insightful)

on Friday February 27, 2004 @05:35PM (#8411930) Homepage
Every time I read something about machines interpreting brain signals, how we might have identified the brain pattern which means "raise my arm," I have to wonder if we're going about this in the fundamentally wrong way.

Why design an arm that has to figure out which brain signals mean "lift up?" Why not design an arm that will respond to brain signals in a number of ways, and one of them is by lifting up? We've each got the best learning device known to our species in our heads, why not use that skill? We all learned to use our original arms through trial and error (albeit when there was a lot less clutter in our heads), I've got the sneaking suspicion that we'd figure out how to make a mechanical one do whatever we want.

It would be no different than learning to swim, or ride a bike, or swing a golf club.

Then all you need is a way to get signals from the brain to the device, and you're set.

• #### Online gaming! Just imagine! (Score:4, Interesting)

on Friday February 27, 2004 @06:56PM (#8412655) Journal
Imagine going head-to-head (hehe) with someone in a game where you both put on your "mind caps" and you battle it out... and the winner is simply the guy who can think the fastest. Forget moving a goofy little thumbstick around and pressing buttons. Imagine the feeling of playing some FPS game and moving around in the game just by sheer willpower. Wow. With good enough graphics, you could probably forget that it's a game pretty easily.

Cool, but a little scary, too.

#### Related LinksTop of the: day, week, month.

You know you've landed gear-up when it takes full power to taxi.

Working...


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# Calling all Fall 2011 Notre Dame Mendoza Applicants

Author Message
Intern
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

### Show Tags

25 Feb 2011, 17:24
Did anyone NOT hear anything? I'm still waiting. I know they have the right number because Mr. Lohr called me to ask me a question.

Posted from my mobile device
Current Student
Status: MSU Bound
Joined: 28 Oct 2010
Posts: 97
Schools: MSU Broad $Followers: 2 Kudos [?]: 7 [0], given: 19 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 25 Feb 2011, 17:29 Not a peep for this guy Manager Joined: 17 Mar 2010 Posts: 64 Location: Boston, MA Schools: Carnegie Mellon Tepper (R2), Duke (R2), Notre Dame (R2), Georgetown (R2), UVA Darden (R2), USC (R2), Kellogg (R2) Followers: 4 Kudos [?]: 5 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 26 Feb 2011, 12:12 Got the call yesterday, left me a voicemail and received an email. Accepted with scholarship, I think scholarship details will be sent to me in a separate email! Intern Joined: 04 Feb 2011 Posts: 7 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 26 Feb 2011, 13:34 calisnoopy wrote: Got the call yesterday, left me a voicemail and received an email. Accepted with scholarship, I think scholarship details will be sent to me in a separate email! I was told that the scholarship details would get sent via USPS and should arrive early this upcoming week. Posted from my mobile device Intern Joined: 26 Feb 2011 Posts: 13 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 26 Feb 2011, 18:08 WL Intern Joined: 13 Aug 2010 Posts: 28 Followers: 0 Kudos [?]: 2 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 26 Feb 2011, 20:01 Got waitlisted Posted from my mobile device Intern Joined: 26 Feb 2011 Posts: 13 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 26 Feb 2011, 20:03 whats ur profile? gmat gpa yrs nationality? Current Student Status: MSU Bound Joined: 28 Oct 2010 Posts: 97 Schools: MSU Broad$
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 00:20
congrats to calisnoops, sorry to the others who joined us on the waitlist
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 06:56
mbanimal2011- what are you going to do to try to get off the waitlist?
Current Student
Status: MSU Bound
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Schools: MSU Broad $Followers: 2 Kudos [?]: 7 [0], given: 19 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 09:54 I'm just trying to be patient. I only contacted the adcom when I had an updated GMAT and work experience. I think you can hurt your chances by pestering them with trivial stuff. We should hear next week Intern Joined: 12 Mar 2010 Posts: 12 Followers: 0 Kudos [?]: 1 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 11:27 I still haven't heard anything. I guess I'll give them a call during business hours tomorrow. Congrats to those who are in and best of luck to those on the waitlist. Posted from my mobile device Manager Joined: 07 Nov 2010 Posts: 73 Followers: 1 Kudos [?]: 7 [0], given: 2 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 11:36 I think i am going to wait for a few days.. I have submitted an additional recommendation and also made it quite clear to the adcom that ND is my first choice school. However, i dont see people with GMAT scores below 700 getting in easily. applies to me too. a good friend of mine just got in with $$and he had a GMAT score of 730. ( other factors do apply but i do think, a gmat score is something they are really looking at as a differentiating factor this year) Intern Joined: 26 Feb 2011 Posts: 13 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 11:48 do they allow other candidates to submit another recommendation? and if so how should i go about doing that? Intern Joined: 04 Feb 2011 Posts: 7 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 12:47 Prometheus59 wrote: I think i am going to wait for a few days.. I have submitted an additional recommendation and also made it quite clear to the adcom that ND is my first choice school. However, i dont see people with GMAT scores below 700 getting in easily. applies to me too. a good friend of mine just got in with$$ and he had a GMAT score of 730. ( other factors do apply but i do think, a gmat score is something they are really looking at as a differentiating factor this year) I have a connection to the President of the Philadelphia chapter of the ND alumni association, and I also heard that ND is looking to improve the average GMAT score of their incoming class this year. That still doesn't mean a whole lot. In the end I'm sure that they want qualifies candidates who can contribute to their program, above all. Posted from my mobile device Current Student Status: MSU Bound Joined: 28 Oct 2010 Posts: 97 Schools: MSU Broad$
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 13:20
Yeah I think their slip in the rankings this year is calling for GMAT boost. Last year they had a really big GMAT range, I guess we'll see.
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 13:22
bgDC wrote:
Prometheus59 wrote:
I think i am going to wait for a few days.. I have submitted an additional recommendation and also made it quite clear to the adcom that ND is my first choice school. However, i dont see people with GMAT scores below 700 getting in easily. applies to me too. a good friend of mine just got in with $$and he had a GMAT score of 730. ( other factors do apply but i do think, a gmat score is something they are really looking at as a differentiating factor this year) I have a connection to the President of the Philadelphia chapter of the ND alumni association, and I also heard that ND is looking to improve the average GMAT score of their incoming class this year. That still doesn't mean a whole lot. In the end I'm sure that they want qualifies candidates who can contribute to their program, above all. Posted from my mobile device There is some relevance to this thought pattern. I do seriously think the gmat score is kinda being used as a tie breaker and not as the primary reason. Nothing beats great work ex. ( as long as your able to showcase that through the essays). this isn't limited to just ND. I see a similar trend across most tier two/ border line tier one schools this year. There is also a distinct rise in the average GMAT score when compared to a couple of years back. Current Student Status: MSU Bound Joined: 28 Oct 2010 Posts: 97 Schools: MSU Broad  Followers: 2 Kudos [?]: 7 [0], given: 19 Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink] ### Show Tags 27 Feb 2011, 13:24 Prometheus59 wrote: I think i am going to wait for a few days.. I have submitted an additional recommendation and also made it quite clear to the adcom that ND is my first choice school. However, i dont see people with GMAT scores below 700 getting in easily. applies to me too. a good friend of mine just got in with$$ and he had a GMAT score of 730. ( other factors do apply but i do think, a gmat score is something they are really looking at as a differentiating factor this year)

Good call Prom, I've heard that if you are on the waitlist at your #1 you should let them know that they are still your #1 choice. It's good to wait though and not look too desperate. I'm having a difficult time ranking my top three choices so I don't want to mislead ND and say I'd for sure go there with an admit. This whole process is insane haha, can't wait until I know what's up for next year. I like to have things planned out pretty well and all of this uncertainty is getting old
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 13:26
mbanimal2011 wrote:
Prometheus59 wrote:
I think i am going to wait for a few days.. I have submitted an additional recommendation and also made it quite clear to the adcom that ND is my first choice school. However, i dont see people with GMAT scores below 700 getting in easily. applies to me too. a good friend of mine just got in with  and he had a GMAT score of 730. ( other factors do apply but i do think, a gmat score is something they are really looking at as a differentiating factor this year)

Good call Prom, I've heard that if you are on the waitlist at your #1 you should let them know that they are still your #1 choice. It's good to wait though and not look too desperate. I'm having a difficult time ranking my top three choices so I don't want to mislead ND and say I'd for sure go there with an admit. This whole process is insane haha, can't wait until I know what's up for next year. I like to have things planned out pretty well and all of this uncertainty is getting old

I will keep my options open though. their stats for picking applicants of wl are certainly not that encouraging.
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 13:29
yeah last year was like 12 out of 150 or something if I remember right. Still though if its your #1 and you hang around I'll bet they will pick you up. Could be a long waiting game though. The student who showed me around campus had a situation like that but he was ND or bust.
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Re: Calling all Fall 2011 Notre Dame Mendoza Applicants [#permalink]

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27 Feb 2011, 14:00
mbanimal2011 wrote:
yeah last year was like 12 out of 150 or something if I remember right. Still though if its your #1 and you hang around I'll bet they will pick you up. Could be a long waiting game though. The student who showed me around campus had a situation like that but he was ND or bust.

very interesting.. did you take some tips from him ? can you now ?? i bet, his story would raise flaggin hopes of other people around on the forum.

i am going to hang out till april. After that , i just have no option but to go someplace else.
Re: Calling all Fall 2011 Notre Dame Mendoza Applicants   [#permalink] 27 Feb 2011, 14:00

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text:
## Statistics (12th Edition)

df = n - 1 = 20 - 1 = 19 $t_{α} = 0.10$ From student's t distribution table, we have: $t_{0.10} = 1.1.328$ Hence rejection region will be: t > 1.328


text:
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# Converting Variables

## 5 posts in this topic

I've learned that the reslt will be 45, but I've never tested it.
If you want to round it, you have to write the following:
code:
float a = 45.426;int b;b = a + 0.5;

This should work... BYE

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As a complement to the post above, i can confirm that the value will be truncated, not rounded.
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Indeed it will be set to 45. Because it just chops the fraction off of it.......

------------------
Dance with me......

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Thanks for the help.
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Also, if you want to make sure of a value being set to one side or other of an integer you can use
double floor(double)...rounds down
and
double ceil(double)...rounds up
from Math.h
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What will result from this:

int x;
float y;

y = 45.54525252552
x = y;

Will x be rounded to 46, or will the fraction just get chopped? And if it is chopped, how can I force it to round up if the fraction is greater than or equal to 1/2?

0

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• 19
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# Challenging sum: Calculate $\sum_{k=1}^\infty\frac{(-1)^{k-1}}{k^52^k{2k \choose k}}$

We proved in our previous solutions here and here the following two sums:

$$\sum_{k=1}^\infty\frac{(-1)^{k-1}}{k^32^k {2k\choose k}}=\frac1{4}\zeta(3)-\frac1{6}\ln^32$$

$$\sum_{k=1}^\infty\frac{(-1)^{k-1}}{k^42^k{2k \choose k}}=4\operatorname{Li}_4\left(\frac12\right)-\frac72\zeta(4)+\frac{13}4\ln2\zeta(3)-\ln^22\zeta(2)+\frac5{24}\ln^42$$

and below I managed to prove the following equality

$$\sum_{k=1}^\infty\frac{(-1)^{k-1}}{k^52^k{2k \choose k}}=10\operatorname{Li}_5\left(\frac12\right)+6\ln2\operatorname{Li}_4\left(\frac12\right)-\frac{19}{2}\zeta(5)+\frac72\ln2\zeta(4)+\ln^22\zeta(3)\\-\frac{2}{3}\ln^32\zeta(2)+\frac{19}{120}\ln^52$$

but solution turned out very long as many results were used in the calculations. I would love to see different methods that save us such tedious work.

By the way, $$k^5$$ is the highest power I could get and I think a sum will be really complicated for higher weight and even has no closed form if we come across $$\sum_{n=1}^\infty\frac{(-1)^nH_n}{n^a}$$ for odd $$a>3$$ as the last has no known closed form.

My solution is too long to be posted here so I will just post it in the answer section.

Different approaches are always appreciated.

thank you all.

Following the same process of our previous solutions of this type of problems:

From here we have $$\arcsin^2z=\frac12\sum_{k=1}^\infty\frac{(2z)^{2k}}{k^2{2k \choose k}}$$ Set $$z=i\sqrt{\frac{y}{8}}$$, we get

$$-\text{arcsinh}^2\left(\sqrt{\frac{y}{8}}\right)=\frac12\sum_{k=1}^\infty\frac{(-1)^{k}y^k}{k^22^k{2k \choose k}}$$ Now multiply both sides by $$-\frac{\ln^2 y}{y}$$ then integrate from $$y=0$$ to $$1$$, we get

\begin{align} S&=\sum_{k=1}^\infty\frac{(-1)^{k-1}}{k^52^k{2k \choose k}}=\int_0^1\frac{\text{arcsinh}^2\left(\sqrt{\frac{y}{8}}\right)\ln^2y}{y}\ dy,\quad \color{red}{\text{arcsinh}\left(\sqrt{\frac{y}{8}}\right)=x}\\ &=2\int_0^{\frac{\ln2}{2}}x^2\ln^2(8\sinh^2x)\coth x\ dx\\ &\small{=18\ln^22\int_0^{\frac{\ln2}{2}}x^2\coth x\ dx+24\ln2\int_0^{\frac{\ln2}{2}}x^2\ln(\sinh x)\coth x\ dx+8\int_0^{\frac{\ln2}{2}}x^2\ln^2(\sinh x)\coth x\ dx}\tag{1}\\ \end{align}

The first integral is calculated here

$$\int_0^{\frac{\ln2}{2}}x^2 \coth x\ dx=\frac1{16}\zeta(3)-\frac1{24}\ln^32\tag{2}$$

and the second integral is calculated here

$$\small{\int_0^{\frac{\ln2}{2}}x^2\ln(\sinh x)\coth x\ dx=-\frac12\operatorname{Li}_4\left(\frac12\right)+\frac7{16}\zeta(4)-\frac12\ln2\zeta(3)+\frac18\ln^22\zeta(2)+\frac{7}{192}\ln^42}\tag{3}$$

As for the third integral, we calculate it as follows

\begin{align} I&=\int_0^{\frac{\ln2}{2}}x^2\ln^2(\sinh x)\coth x\ dx,\quad \color{red}{x=\ln y}\\ &=\int_0^{\sqrt{2}}\ln^2y\ln^2\left(\frac{y^2-1}{2y}\right)\left(\frac{y^2+1}{y^2-1}\right)\frac{\ dy}{y},\quad \color{red}{y^2-1=x}\\ &=\frac18\int_0^1\ln^2(1+x)\left(\ln x-\ln2-\frac12\ln(1+x)\right)^2\left(\frac{2}{x}-\frac1{1+x}\right)\ dx\\ &\small{=\frac14\int_0^1\frac{\ln^2(1+x)\ln^2x}{x}+\frac1{16}\int_0^1\frac{\ln^4(1+x)}{x}-\frac14\int_0^1\frac{\ln^3(1+x)\ln x}{x}-\frac12\ln2\int_0^1\frac{\ln^2(1+x)\ln x}{x}\\ +\frac14\ln2\int_0^1\frac{\ln^3(1+x)}{x}+\frac14\ln^22\int_0^1\frac{\ln^2(1+x)}{x}-\frac18\underbrace{\int_0^1\frac{\ln^2(1+x)\ln^2x}{1+x}}_{\large IBP}-\frac1{32}\underbrace{\int_0^1\frac{\ln^4(1+x)}{1+x}}_{\large \frac15\ln^52}\\+\frac18\underbrace{\int_0^1\frac{\ln^3(1+x)\ln x}{1+x}}_{\large IBP}+\frac14\ln2\underbrace{\int_0^1\frac{\ln^2(1+x)\ln x}{1+x}}_{\large IBP}-\frac18\ln2\underbrace{\int_0^1\frac{\ln^3(1+x)}{1+x}}_{\large\frac14\ln^42}-\frac18\ln^22\underbrace{\int_0^1\frac{\ln^2(1+x)}{1+x}}_{\large\frac13\ln^32}}\\ &\small{=\frac14\underbrace{\int_0^1\frac{\ln^2(1+x)\ln^2x}{x}}_{\Large I_1}+\frac1{32}\underbrace{\int_0^1\frac{\ln^4(1+x)}{x}}_{\Large I_2}-\frac16\underbrace{\int_0^1\frac{\ln^3(1+x)\ln x}{x}}_{\Large I_3}-\frac12\ln2\underbrace{\int_0^1\frac{\ln^2(1+x)\ln x}{x}}_{\Large I_4}\\+\frac16\ln2\underbrace{\int_0^1\frac{\ln^3(1+x)}{x}}_{\Large I_5}+\frac14\ln^22\underbrace{\int_0^1\frac{\ln^2(1+x)}{x}}_{\Large I_6}-\frac{19}{240}\ln^52}\text{}\tag{4} \end{align} (Ignoring $$dx$$ is intended so no need to edit please)

The result of $$I_3$$ can be found here

$$\boxed{\small{I_3=-12\operatorname{Li}_5\left(\frac12\right)-12\ln2\operatorname{Li}_4\left(\frac12\right)+\frac{99}{16}\zeta(5)+3\zeta(2)\zeta(3)-\frac{21}4\ln^22\zeta(3)+2\ln^32\zeta(2)-\frac25\ln^52}}$$

and the results of $$I_4$$, $$I_5$$ and $$I_6$$ can be found here

$$\boxed{I_4=-4\operatorname{Li_4}\left(\frac12\right)+\frac{15}4\zeta(4)-\frac72\ln2\zeta(3)+\ln^22\zeta(2)-\frac{1}{6}\ln^42}$$

$$\boxed{I_5=-6\operatorname{Li}_4\left(\frac12\right)+6\zeta(4)-\frac{21}{4}\ln2\zeta(3)+\frac32\ln^22\zeta(2)-\frac14\ln^42}$$

$$\boxed{I_6=\frac14\zeta(3)}$$

and now we are left with the remaining integrals $$I_1$$ and $$I_2$$ and lets start with the first one.

By using $$\ln^2(1+x)=2\sum_{n=1}^\infty\frac{H_n}{n+1}(-x)^{n+1}=2\sum_{n=1}^\infty(-1)^n\left(\frac{H_n}{n}-\frac1{n^2}\right)x^n$$

we get

\begin{align} I_1&=\int_0^1\frac{\ln^2(1+x)\ln^2x}{x}\ dx=2\sum_{n=1}^\infty(-1)^n\left(\frac{H_n}{n}-\frac1{n^2}\right)\int_0^1x^{n-1}\ln^2x\ dx\\ &=2\sum_{n=1}^\infty(-1)^n\left(\frac{H_n}{n}-\frac1{n^2}\right)\left(\frac{2}{n^3}\right)=4\sum_{n=1}^\infty\frac{(-1)^nH_n}{n^4}-4\operatorname{Li}_5(-1)\\ &=4\left(\frac12\zeta(2)\zeta(3)-\frac{59}{32}\zeta(5)\right)-4\left(-\frac{15}{16}\zeta(5)\right)\\ &\boxed{I_1=2\zeta(2)\zeta(3)-\frac{29}{8}\zeta(5)} \end{align}

The sum $$\sum_{n=1}^\infty\frac{(-1)^nH_n}{n^4}$$ was nicely done here by M.N.C.E and Cornel Valean.

\begin{align} I_2&=\int_0^1\frac{\ln^4(1+x)}{x}\ dx\overset{x=\frac{1-y}{y}}{=}\int_{1/2}^1\frac{\ln^4x}{x(1-x)}\ dx\\ &=\int_{1/2}^1\frac{\ln^4x}{x}\ dx+\int_{1/2}^1\frac{\ln^4x}{1-x}\ dx\\ &=\frac15\ln^52+\sum_{n=1}^\infty \int_{1/2}^1x^{n-1}\ln^4 x\ dx\\ &=\frac15\ln^52+\sum_{n=1}^\infty\left(-\frac{\ln^42}{n2^n}-\frac{4\ln^32}{n^22^n}-\frac{12\ln^22}{n^32^n}-\frac{24\ln2}{n^42^n}-\frac{24}{n^52^n}+\frac{24}{n^5}\right)\\ &=\frac15\ln^52-\ln^52-4\ln^32\operatorname{Li}_2\left(\frac12\right)-12\ln^22\operatorname{Li}_3\left(\frac12\right)-24\ln2\operatorname{Li}_4\left(\frac12\right)-24\operatorname{Li}_5\left(\frac12\right)+24\zeta(5)\\ &\boxed{I_2=-24\operatorname{Li}_5\left(\frac12\right)-24\ln2\operatorname{Li}_4\left(\frac12\right)+24\zeta(5)+4\ln^3(2)\zeta(2)-\frac{21}2\ln^22\zeta(3)-\frac45\ln^52} \end{align}

In our calculations, we used the following special values of the dilogarithmic and trilogarithmic functions:

$$\operatorname{Li_2}\left( \frac12\right) =\frac12\zeta(2)-\frac12\ln^22$$

$$\operatorname{Li_3}\left( \frac12\right)=\frac78\zeta(3)-\frac12\ln2\zeta(2)+\frac16\ln^32$$

Plugging the boxed results of $$I_1$$, $$I_2$$, $$I_3$$, $$I_4$$, $$I_5$$ and $$I_6$$ in $$(4)$$, we get

$$\small{I=\frac54\operatorname{Li}_5\left(\frac12\right)+\frac94\ln2\operatorname{Li}_4\left(\frac12\right)-\frac{19}{16}\zeta(5)-\frac78\ln2\zeta(4)+\frac{95}{64}\ln^22\zeta(3)-\frac{11}{24}\ln^32\zeta(2)+\frac1{240}\ln^52}\tag{5}$$

Finally, by substituting the results of $$(2)$$, $$(3)$$, and $$(5)$$ in $$(1)$$, we get our closed form:

$$\small{S=10\operatorname{Li}_5\left(\frac12\right)+6\ln2\operatorname{Li}_4\left(\frac12\right)-\frac{19}{2}\zeta(5)+\frac72\ln2\zeta(4)+\ln^22\zeta(3)-\frac{2}{3}\ln^32\zeta(2)+\frac{19}{120}\ln^52}$$


text:
# Showing that a sequence does not converge uniformly to a piecewise function

I understood how to show that a sequence converge pointwise and uniformly to another function. However, I am finding it difficult to show that a function DOES NOT converge uniformly to a function, in particular when the pointwise limit is piecewise. Let me give an example:

Let $f_n(x)=\dfrac{x}{1+x^n}$ for $n\in \mathbb{N}$ and $x\in[0, \infty)$

I am required to find the pointwise limit, which I found to be:

$$f(x)= \begin{cases} x \ , \ x\in[0, 1)\\ \frac{1}{2} \ , \ x=1\\ 0 \ , \ x\in(1, \infty) \end{cases}$$

Now for the second part of the question, I am required to show that it does not converge uniformly. I understand that the reason for this (intuitively) is because there is a sort of "jump" at $x=1$

My attempt was as follows:

Let $x=1+\frac{1}{n}$

Now I try to show that for any $N\in\mathbb{N}$ , $\exists n\geq N$, such that $|f_n-f|>\epsilon$ for some $\epsilon$.

Let $\epsilon=1/4$ and let $n>\dfrac{1}{\sqrt[N]{3}-1}$

$$|f_N(x)-f(x)|$$ $$=\left|\dfrac{x}{1+x^N}-0\right|$$ $$=\left|\dfrac{x}{1+x^N}\right|$$ $$=\left|\dfrac{1+\frac{1}{n}}{1+(1+\frac{1}{n})^N}\right|$$ $$>\dfrac{1}{1+(1+\frac{1}{n})^N}$$ $$>1/4=\epsilon$$

First of all I am not sure if this method is correct, and even if it is, is this the best way to go about showing uniform convergence, at least in this case?

I am aware that uniform convergence occurs iff $\lim_{n\rightarrow \infty}\sup{|f_n(x)-f(x)|}=0$, but I cannot see how to use this since the pointwise limit is a piecewise function.

Each $f_n$ is continuous, but $f$ isn't. Therefore, the convergence is not uniform.


text:
MSG SEVIRI RGB composites¶

This notebook provides you an introduction to Level 1.5 data from the SEVIRI instrument as part of the Meteosat Second Generation 0 Degree Service. It further provides you an introduction to the Python package satpy which allows for an efficient handling of data from meteorological satellite instruments, including SEVIRI and MODIS. At the end, a specific focus will be put on the SEVIRI Dust RGB, whose primary aim is to detect dust in the atmosphere.

The example features the saharan dust event during 5./6. February 2021, which brought massive amounts of Saharan dust into central Europe. See a more detailed description of this particular event here.

The Meteosat series have been providing crucial data for weather forecasting since 1977 and is a series of geostationary satellites providing imagery for weather forecasting and climate monitoring. Meteosat Second Genersation (MSG) is the current fleet of operational geostationary satellites. The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) is MSG’s primary instrument and has the capacity to observe the Earth in 12 spectral channels. 11 channels provides measurements with a resolution of 3 km at the sub-satellite and one, the High Resolution Visible (HRV) channel, provides measurements with a resolution of 1 km.

The SEVIRI instrument allows for a complete image scan (Full Earth Scan) every 15 minutes. The 0 Degree Service is the main mission of MSG and provides High Rate SEVIRI image data in 12 spectral bands, processed in near real-time to Level 1.5.

Basic facts

Spatial resolution: 1 km at nadir
Spatial coverage: Latitude: -81 to 81 degrees, Longitude: -79 to 79 degrees
Revisit time: every 15 minutes
Data availability: since 2004

How to access the data

High Rate SEVIRI Level 1.5 Image Data is available for download via the EUMETSAT Data Store. You need to register for the EUMETSAT Earth Observation Portal in order to be able to download data from the Data Store.

import glob
import xarray as xr
import numpy as np

import matplotlib.pyplot as plt
import matplotlib.colors
from matplotlib.axes import Axes

import cartopy
import cartopy.crs as ccrs
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER
from cartopy.mpl.geoaxes import GeoAxes
GeoAxes._pcolormesh_patched = Axes.pcolormesh

from satpy.scene import Scene
from satpy.composites import GenericCompositor
from satpy.writers import to_image
from satpy.resample import get_area_def

import pyresample

import warnings
warnings.filterwarnings('ignore')
warnings.simplefilter(action = "ignore", category = RuntimeWarning)

%run ../../functions.ipynb

MSG SEVIRI True color composite¶

Load and browse High Rate SEVIRI Level 1.5 image data¶

Meteosat Second Generation data are disseminated in the specific MSG Level 1.5 Native format. The Python package satpy supports reading and loading data from many input files. With the function available_readers(), you can get a list of all available readers satpy offers. For MSG data and the Native format, you can use the reader seviri_l1b_native.

available_readers()

From the EUMETSAT Data Store, we downloaded for severals hours from 5./6. February 2021 of High Rate SEVIRI Level 1.5 Image data. The data is available in the folder ../../eodata/1_satellite/meteosat/event/. Let us load one image scence for 6 February at 7.27 UTC. First, we specify the file path and create a variable with the name file_name.

file_name = glob.glob('../../eodata/1_satellite/meteosat/event/*2021020607*.nat')
file_name

In a next step, we use the Scene constructor from the satpy library. Once loaded, a Scene object represents a single geographic region of data, typically at a single continuous time range.

You have to specify the two keyword arguments reader and filenames in order to successfully load a scene. As mentioned above, for MSG SEVIRI data in the Native format, you can use the seviri_l1b_native reader.

scn = Scene(reader="seviri_l1b_native",
filenames=file_name)
scn

<satpy.scene.Scene at 0x7fdb8f7cda90>

A Scene object loads all band information of a satellite image. With the function available_dataset_names(), you can see the available bands available from the MSG SEVIRI satellite.

scn.available_dataset_names()

['HRV',
'IR_016',
'IR_039',
'IR_087',
'IR_097',
'IR_108',
'IR_120',
'IR_134',
'VIS006',
'VIS008',
'WV_062',
'WV_073']

The underlying container for data in satpy is the xarray.DataArray. With the function load(), you can specify an individual band by name, e.g. IR_108 and load the data. If you then select the loaded band, you see that the band object is a xarray.DataArray.

scn.load(['IR_108'])
scn['IR_108']

<xarray.DataArray 'reshape-7f46b2a2eee50e746a278c951ee5cd2d' (y: 3712, x: 3712)>
dask.array<truediv, shape=(3712, 3712), dtype=float32, chunksize=(3712, 3712), chunktype=numpy.ndarray>
Coordinates:
acq_time  (y) datetime64[ns] NaT NaT NaT NaT NaT NaT ... NaT NaT NaT NaT NaT
crs       object PROJCRS["unknown",BASEGEOGCRS["unknown",DATUM["unknown",...
* y         (y) float64 -5.566e+06 -5.563e+06 ... 5.566e+06 5.569e+06
* x         (x) float64 5.566e+06 5.563e+06 5.56e+06 ... -5.566e+06 -5.569e+06
Attributes: (12/17)
orbital_parameters:       {'projection_longitude': 0.0, 'projection_latit...
units:                    K
wavelength:               10.8 µm (9.8-11.8 µm)
standard_name:            toa_brightness_temperature
platform_name:            Meteosat-11
sensor:                   seviri
...                       ...
name:                     IR_108
resolution:               3000.403165817
calibration:              brightness_temperature
modifiers:                ()
_satpy_id:                DataID(name='IR_108', wavelength=WavelengthRang...
ancillary_variables:      []

With an xarray data structure, you can handle the object as a xarray.DataArray. For example, you can print a list of available attributes with the function attrs.keys().

scn['IR_108'].attrs.keys()

dict_keys(['orbital_parameters', 'units', 'wavelength', 'standard_name', 'platform_name', 'sensor', 'georef_offset_corrected', 'start_time', 'end_time', 'reader', 'area', 'name', 'resolution', 'calibration', 'modifiers', '_satpy_id', 'ancillary_variables'])

With the attrs() function, you can also access individual metadata information, e.g. start_time and end_time.

scn['IR_108'].attrs['start_time'], scn['IR_108'].attrs['end_time']

(datetime.datetime(2021, 2, 6, 7, 15, 11, 201331),
datetime.datetime(2021, 2, 6, 7, 30, 10, 197941))

But for now, let us reload the data file from the beginning. We do not need the IR_108 channel for the next steps, but rather would like to focus on different RGB composites.

scn = Scene(reader="seviri_l1b_native",
filenames=file_name)
scn

<satpy.scene.Scene at 0x7f05fb7933a0>

Browse and visualize RGB composite IDs¶

RGB composites combine multiple window channels of satellite data in order to get e.g. a true-color image of the scene. Depending on the channel combination used, different features can be highlighted in the composite, e.g. dust. SatPy offers several predefined RGB composites options. The function available_composite_ids() returns a list of available composite IDs. You see that there are predefined composites for e.g. natural_color, snow or dust.

scn.available_composite_ids()

[DataID(name='airmass'),
DataID(name='ash'),
DataID(name='cloudtop'),
DataID(name='cloudtop_daytime'),
DataID(name='colorized_ir_clouds'),
DataID(name='convection'),
DataID(name='day_microphysics'),
DataID(name='day_microphysics_winter'),
DataID(name='dust'),
DataID(name='fog'),
DataID(name='green_snow'),
DataID(name='hrv_clouds'),
DataID(name='hrv_fog'),
DataID(name='hrv_severe_storms'),
DataID(name='ir108_3d'),
DataID(name='ir_cloud_day'),
DataID(name='ir_overview'),
DataID(name='ir_sandwich'),
DataID(name='natural_color'),
DataID(name='natural_color_nocorr'),
DataID(name='natural_color_raw'),
DataID(name='natural_color_with_night_ir'),
DataID(name='natural_color_with_night_ir_hires'),
DataID(name='natural_enh'),
DataID(name='natural_enh_with_night_ir'),
DataID(name='natural_enh_with_night_ir_hires'),
DataID(name='natural_with_night_fog'),
DataID(name='night_fog'),
DataID(name='night_ir_alpha'),
DataID(name='night_ir_with_background'),
DataID(name='night_ir_with_background_hires'),
DataID(name='night_microphysics'),
DataID(name='overview'),
DataID(name='overview_raw'),
DataID(name='realistic_colors'),
DataID(name='snow'),
DataID(name='vis_sharpened_ir')]

Let us define a list with the composite ID natural_color. This list (composite_id) can then be passed to the function load(). Per default, scenes are loaded with the north pole facing downwards. You can specify the keyword argument upper_right_corner="NE" in order to turn the image around and have the north pole facing upwards.

composite_id = ['natural_color']

A print of the Scene object scn shows you that it consists of one xarray.DataArray with the standard name natural_color.

print(scn)

<xarray.DataArray 'where-c726622c80224770c3c041125613789c' (bands: 3, y: 3712, x: 3712)>
dask.array<where, shape=(3, 3712, 3712), dtype=float64, chunksize=(1, 3712, 3712), chunktype=numpy.ndarray>
Coordinates:
crs      object PROJCRS["unknown",BASEGEOGCRS["unknown",DATUM["unknown",E...
* y        (y) float64 5.569e+06 5.566e+06 5.563e+06 ... -5.563e+06 -5.566e+06
* x        (x) float64 -5.569e+06 -5.566e+06 ... 5.563e+06 5.566e+06
* bands    (bands) <U1 'R' 'G' 'B'
Attributes: (12/20)
georef_offset_corrected:                True
area:                                   Area ID: msg_seviri_fes_3km\nDesc...
end_time:                               2021-02-06 07:30:10.197941
platform_name:                          Meteosat-11
sun_earth_distance_correction_applied:  True
...                                     ...
optional_datasets:                      []
name:                                   natural_color
_satpy_id:                              DataID(name='natural_color', reso...
prerequisites:                          [DataQuery(name='IR_016', modifie...
optional_prerequisites:                 []
mode:                                   RGB

The function show() allows you to visualize a loaded composite or band. Let us e.g. visualize the natural_color composite. Once visualized, you see that the RGB composite highlights clouds in turquoise, but highlights specific features in their natural color.

scn.show('natural_color')

Generate a geographical subset for southern Europe¶

The visualization above looks nice, but in many cases you might want to highlight a specific geographical region. Let us generate a geographical subset for southern Europe. You can do this with the function crop() and specifying the keyword argument ll_bbox=(lon_min, lat_min, lon_max, lat_max). Let us take the following bounding box information with a focus over Portugal and Spain: (-5.0, 31.0, 20.0, 51.0).

Afterwards, you can visualize the cropped image with the function show().

scn_cropped = scn.crop(ll_bbox=(-5, 31, 20, 51))
scn_cropped.show("natural_color")

From the cropped image, you can load the area information that is stored as an attribute entry. The area attribute holds information related to the projection, number of columns / rows and area extent.

Note: the area extent key provides x and y values in meters from the nadir, which is the original projection unit.

scn_cropped['natural_color'].attrs['area']

Area ID: msg_seviri_fes_3km
Description: MSG SEVIRI Full Earth Scanning service area definition with 3 km resolution
Projection: {'a': '6378169', 'h': '35785831', 'lon_0': '0', 'no_defs': 'None', 'proj': 'geos', 'rf': '295.488065897014', 'type': 'crs', 'units': 'm', 'x_0': '0', 'y_0': '0'}
Number of columns: 750
Number of rows: 482
Area extent: (-454561.0796, 3151923.5257, 1795741.2947, 4598117.8516)

Another possibility is to crop the data with x and y values in original projection unit (x_min, y_min, x_max, y_max). In the case of MSG SEVIRI data, the projection unit is meters (distance from the nadir). Below we apply the funcion crop() again, but instead of ll_bbox, we use this time the keyword argument xy_bbox=(xmin, ymin, xmax, ymax) and slightly adjust the x and y values from the area extent attribute above.

When we visualize the cropped image again with the function show(), you see that the extent is more or less the same. The adjustment of ymin and ymax has increased the extent towards the north and the south.

scn_cropped = scn.crop(xy_bbox=(-5E5, 30E5, 20E5, 48E5))
scn_cropped.show("natural_color")

As a next step, let us store the area definition as variable and call it area. We can can use the area information to resample the loaded scene object in a next step.

area = scn_cropped['natural_color'].attrs['area']
area

Area ID: msg_seviri_fes_3km
Description: MSG SEVIRI Full Earth Scanning service area definition with 3 km resolution
Projection: {'a': '6378169', 'h': '35785831', 'lon_0': '0', 'no_defs': 'None', 'proj': 'geos', 'rf': '295.488065897014', 'type': 'crs', 'units': 'm', 'x_0': '0', 'y_0': '0'}
Number of columns: 835
Number of rows: 601
Area extent: (-502567.5303, 2998902.9642, 2002769.1132, 4802145.2669)

Cropping is nice and for our geographical area of interest the cropped image looks acceptable. However, when working with regions close to the marging of the scene, the cropped scene can look very distorted, due to the viewing angle of the satellite. For this reason, it is recommended to use the function resample() from the library pyresample, which resamples the loaded scene to a custom area and projection.

Pyresample offers predefined areas; a list of those can be found in the satpy package under /satpy/etc/ in the file areas.yaml. There is no predefined area for our region. For this reason, we can make use of the variable area, which we defined above and which has all the area information needed by the resample() function. Below, we simply pass the area variable to the resample() function.

scn_resample_nc = scn.resample(area)
scn_resample_nc.show('natural_color')

Visualize MSG SEVIRI true color composite with Cartopy features¶

SatPy’s built-in visualization function is nice, but often you want to make use of additonal features, such as country borders. The library Cartopy offers powerful functions that enable the visualization of geospatial data in different projections and to add additional features to a plot. Below, we will show you how you can visualize the natural_color composite with the two Python packages matplotlib and Cartopy.

As a first step, we have to convert the Scene object into a numpy array. The numpy array additionally needs to be transposed to a shape that can be interpreted by matplotlib’s function imshow(): (M,N,3). You can convert a Scene object into a numpy.array object with the function np.asarray().

The shape of the array is (3, 601, 667). This means we have to transpose the array and add index=0 on index position 3.

image = np.asarray(scn_resample_nc["natural_color"]).transpose(1,2,0)
image.shape

(601, 835, 3)

In a next step, we scale the values to a range between 0 and 1 and we clip the lower and upper percentiles. This process sharpens the contrast, as a potential contrast decrease caused by outliers is eliminated.

image = np.interp(image, (np.percentile(image,1), np.percentile(image,99)), (0, 1))

Let us now also define a variable for the coordinate reference system. We take the area attribute from she scn_resample_nc Scene and convert it with the function to_cartopy_crs() into a format Cartopy can read. We will use the crs information for plotting.

crs = scn_resample_nc["natural_color"].attrs["area"].to_cartopy_crs()

Now, we can visualize the natural_color composite. The plotting code can be divided in four main parts:

• Initiate a matplotlib figure: Initiate a matplotlib plot and define the size of the plot

• Specify coastlines and a grid: specify additional features to be added to the plot

• Plotting function: plot the numpy array with the plotting function imshow()

• Set plot title: specify title of the plot

# Initiatie a subplot and axes with the CRS information previously defined
fig = plt.figure(figsize=(16, 10))
ax = fig.add_subplot(1, 1, 1, projection=crs)

# Add coastline features to the plot
ax.coastlines(resolution="10m", color="white")

# Define a grid to be added to the plot
gl = ax.gridlines(draw_labels=True, linestyle='--', xlocs=range(-10,11,5), ylocs=range(30,50,5))
gl.top_labels=False
gl.right_labels=False
gl.xformatter=LONGITUDE_FORMATTER
gl.yformatter=LATITUDE_FORMATTER
gl.xlabel_style={'size':14}
gl.ylabel_style={'size':14}

# In the end, we can plot our image data...
ax.imshow(image, transform=crs, extent=crs.bounds, origin="upper")

# Define a title for the plot
plt.title("Natural color composite of southern Europe, recorded by MSG at " + scn_resample_nc.attrs["start_time"].strftime("%Y-%m-%d %H:%M"), fontsize=20, pad=20.0)

Text(0.5, 1.0, 'Natural color composite of southern Europe, recorded by MSG at 2021-02-06 07:15')

MSG SEVIRI Dust RGB composite¶

In a final step, we would like to have a closer look at the SEVIRI Dust RGB composite, whose primary aim is to support the detection of dust in the atmosphere. The dust composite makes use of three window channels of Meteosat Second Generation:

• Red: IR12.0-IR10.8

• Green: IR10.8-IR.8.7

• Blue: IR10.8

Let us first again load the image from 6 February 2021 at 7.27 UTC as a pytroll Scene object again.

file_name = glob.glob('../../eodata/1_satellite/meteosat/event/*2021020607*.nat')
file_name

Now, let us define a list with the predefined dust RGB composite and let us load this composite with the function load(). Remember, by specifying the keyword argument upper_right_corner='NE', you load the image with North facing upwards.

composite_id = ['dust']

The, we can directly resample the image to the area defined above. You can use the area object and the function resample() to resample the dust RGB composite to the area of interest.

scn_resample_dust = scn.resample(area)

And in a last step, we can visualize the dust composite with Satpy’s built-in visualization function show(). The colours of the dust RGB can be interpreted as follows:

• Magenta: Dust or ash clouds

• Black: Cirrus clouds

• Dark red: Thick, high and cold ice clouds

• Yellow: Thick mid-level clouds

• Darkblue: Humid air in lower levels

• Lilac: Dry air in lower levels

scn_resample_dust.show('dust')


text:
Credit-Based Shaping¶

Goals¶

In this example we demonstrate how to use the credit-based traffic shaper.

INET version: 4.4

The Model¶

There are three network nodes in the network. The client and the server are TsnDevice modules, and the switch is a TsnSwitch module. The links between them use 100 Mbps EthernetLink channels.

There are four applications in the network creating two independent data streams between the client and the server. The data rate of both streams are ~48 Mbps at the application level in the client.

# client applications
*.client.numApps = 2
*.client.app[*].typename = "UdpSourceApp"
*.client.app[0].display-name = "best effort"
*.client.app[1].display-name = "video"
*.client.app[0].io.destPort = 1000
*.client.app[1].io.destPort = 1001
*.client.app[*].source.packetLength = 1000B
*.client.app[0].source.productionInterval = exponential(200us)
*.client.app[1].source.productionInterval = exponential(400us)

# server applications
*.server.numApps = 2
*.server.app[*].typename = "UdpSinkApp"
*.server.app[0].display-name = "best effort"
*.server.app[1].display-name = "video"
*.server.app[0].io.localPort = 1000
*.server.app[1].io.localPort = 1001

The two streams have two different traffic classes: best effort and video. The bridging layer identifies the outgoing packets by their UDP destination port. The client encodes and the switch decodes the streams using the IEEE 802.1Q PCP field.

# enable outgoing streams
*.client.hasOutgoingStreams = true

# client stream identification
*.client.bridging.streamIdentifier.identifier.mapping = [{stream: "best effort", packetFilter: expr(udp.destPort == 1000)},
{stream: "video", packetFilter: expr(udp.destPort == 1001)}]

# client stream encoding
*.client.bridging.streamCoder.encoder.mapping = [{stream: "best effort", pcp: 0},
{stream: "video", pcp: 4}]

The traffic shaping takes place in the outgoing network interface of the switch where both streams pass through. The traffic shaper limits the data rate of the best effort stream to 40 Mbps and the data rate of the video stream to 20 Mbps. The excess traffic is stored in the MAC layer subqueues of the corresponding traffic class.

# enable egress traffic shaping
*.switch.hasEgressTrafficShaping = true

# credit based traffic shaping
*.switch.eth[*].macLayer.queue.numTrafficClasses = 2
*.switch.eth[*].macLayer.queue.*[0].display-name = "best effort"
*.switch.eth[*].macLayer.queue.*[1].display-name = "video"
*.switch.eth[*].macLayer.queue.transmissionSelectionAlgorithm[*].typename = "Ieee8021qCreditBasedShaper"
*.switch.eth[*].macLayer.queue.transmissionSelectionAlgorithm[0].idleSlope = 42.68Mbps # Channel data rate
*.switch.eth[*].macLayer.queue.transmissionSelectionAlgorithm[1].idleSlope = 21.34Mbps # Channel data rate

Results¶

The first diagram shows the data rate of the application level outgoing traffic in the client. The data rate varies randomly over time for both traffic classes but the averages are the same.

The next diagram shows the data rate of the incoming traffic of the traffic shapers. This data rate is measured inside the outgoing network interface of the switch. This diagram is somewhat different from the previous one because the traffic is already in the switch, and also because it is measured at a different protocol level.

The next diagram shows the data rate of the already shaped outgoing traffic of the traffic shapers. This data rate is still measured inside the outgoing network interface of the switch but at a different location. As it is quite apparent, the randomly varying data rate of the incoming traffic is already transformed here into a quite stable data rate.

The next diagram shows the queue lengths of the traffic classes in the outgoing network interface of the switch. The queue lengths increase over time because the data rate of the incoming traffic of the traffic shapers is greater than the data rate of the outgoing traffic, and packets are not dropped.

TODO

TODO

The next diagram shows the relationships between the number of credits, the gate state of the credit based transmission selection algorithm, and the transmitting state of the outgoing network interface for the both traffic classes.

The last diagram shows the data rate of the application level incoming traffic in the server. The data rate is somewhat lower than the data rate of the outgoing traffic of the corresponding traffic shaper. The reason is that they are measured at different protocol layers.

Sources: omnetpp.ini

Discussion¶

Use this page in the GitHub issue tracker for commenting on this showcase.


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# Lock Box

(Redirected from Blink box)

## Overview

Everybody has something valuable which they do not want to be stolen. This is why some people decide to put their things in a lockable box. The Lock Box project involves making just that: a box that the user can lock and unlock and hold his/her things. The box can be unlocked by turning a dial like a combination padlock, but instead of the code being physically ingrained in the device, it is digitally stored and changeable. An Arduino Uno, ten Hall Effect sensors, some magnets, and a button are used to accomplish this. The Arduino is coded to have two different codes: one that is shorter (4 digits) and resettable, and one that is longer (8 digits) and permanent. The user can either unlock the box or reset the code by inputting the shorter code. The longer, permanent code is used as a backup code in case the user forgets what he/she set the shorter code to. The way the user interfaces with the Arduino is by pressing a button for a certain amount of time: single press to unlock and hold it down to reset the code. The state of the box is indicated by two LEDs so that the user can use the box more easily.

Yuanxiao Gao
Samuel Hoff
TA: Mo Wu

## Objectives

Make a box that is is able to be unlocked by putting in the correct combination. The combination will be entered by turning a dial, just like combination padlock. When the dial turns to a specific number, there will be a signal sent to an Arduino. When the user wants to enter a code he will press a button to select the action he wants to perform (change the code or unlock the box) and then enter the code with the dial. The way the number will be translated from the position of the dial to a number of the code is by using a Hall Effect sensor to detect a unique signal from the magnets. There will be two codes: one that is 4 digits long and one that is twice is long. The first code is changeable and when entered can both open the box and allow the user to change it. The second is a backup code that allows the user to change the first code, in case the user forgets the code.

The main goals of this project are to:
1. Design a dial and housing that allows the dial's position to an Arduino.

2. Build the interface that allows the user to specify which code he will be entering.

3. Write C++ code on Arduino IDE that allows the user to control the box.

4. Design the locking mechanism and the bottom part of the box.

5. Assemble and test.

## Challenges

Accurately reading a number based on the position of the dial.

Writing code to perform all of the functionality desired.

Finding a proper power supply.

Connecting all the parts into the circuit.

Coding in the language that will be read by Arduino.

## Budget

LEDs (Provided)

3-D printing (Provided)

Arduino UNO (Provided)

Push Pull Solenoid Motor ($19.11) https://www.adafruit.com/product/412 Hall Effect Sensors X 13 ($39.08) https://vetco.net/products/hall-effect-sensor-module-for-arduino?gclid=EAIaIQobChMIxJnC_dmC2AIV1UsNCh2s3w95EAQYASABEgIEe_D_BwE

Total: \$71.10

## Design and Solution

1. First, we have to test the hall effect sensors by connecting it to the Arduino. The “-” pin goes to the ground. The “S” pin goes to signal. The middle pin goes the power supply. We also need to place a 10K resistor between the “S” pin and the middle pin. .

2. After setting up the circuit and writing the simple code on the How to use hall effect sensor page on the Arduino, you can see the LED turns on when magnets are near the sensor. .

3. After this we started soldering all then hall effect sensors and resistors together in the shape of a circle and connected each sensor to the signal pin on the Arduino..

4. After finishing setting up the sensors, we added two LED lights to the circuit because we need them to show each state of the lock and also connected the button into the circuit which is used to change the state of the lock by pressing it once or pressing and holding it..

5. Then we need to connect the motor and the relay into the circuit. There are 4 pins on the relay we use. Pin1 goes to power Arduino. Pin2 goes to ground Arduino. Pin3 goes the positive of the batteries. Pin4 goes the negative..

6. We 3D printed the dial and the lid of the box. We glued all the parts on the lid and put the magnets in the dial and set the dial in the mid of the lid. The picture below shown how it is set up.

7. By coding, we accomplished the whole project. Code is attached below.

## Results

Our project is used just like a combination lock but the difference is what is inside. We put magnets in the dial and set 10 hall effect sensors around it. With 10 different inputs, Arduino can read number 0 to number 9. There is a resettable 4 digit code that the user can unlock the box with. There is an 8 digit backup code that can be entered to change the 4 digit code. The user selects an action with a button: a single press to unlock, hold to reset the code. Two LEDs are used to indicate the state. And it is exactly what we wanted it to be so our project is successful. We could have made it better if we 3D printed the box which would make the box more secure. For now, we just used cardboard. And also, when we were doing it found out that insufficient batteries is also a problem. We had to keep changing the batteries when the old batteries had been ran out. To make it better, we can maybe set another button to turn on/off the box which can make us use it longer. This could have been due to the wiring of the hall effect sensors, but it is not clear yet. Another improvement would be to remove the wires and replace them with a printed conductive material.
Link to the revised tutorial: https://classes.engineering.wustl.edu/ese205/core/index.php?title=Use_Hall_Effect_Sensors


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# INTEREST-RATE RULES: The Welfare Loss from Price-Level Instability 2

Linearization around this particular (optimal) steady state is extremely convenient, since our approximate measure of W takes an especially simple form in that case. In particular, in this case our second-order approximation for W depends only upon a first-order approximation to the equilibrium responses of inflation and output to the exogenous shocks. This means that we can solve a log-linear approximation to the model’s equilibrium conditions using standard linear methods, as sketched in the previous subsection, and obtain an approximation to W that neglects only terms of third order and higher in the deviations from the steady state. This result depends upon the absence of any first-order contribution to our welfare measure from changes in the average level of output under alternative rules (as a result of the optimality of the level Y relative to which we consider deviations); for if W contained a term of first order in the average level of output, then second-order terms in the equations determining output would matter for a second-order approximation to W. If quick loans cash can fix your financial problems right now, then you should get that money from a lender you can trust without waiting any further. We will be glad to help you by offering a loan for as long as you need. Come and find our offer at Link and see how affordable those loans are.

In fact, in the calculations reported here, we furthermore assume that the tax rate r actually varies depending on the monetary policy rule, so as to ensure that E[\ogYt) = log Y in any event. This allows us to obtain a measure of the deadweight loss associated with price-level instability that abstracts from any effects of alternative monetary policies upon the long-run average level of output. While many analyses of the welfare effects of monetary policy have emphasized exactly such effects, we think there is good reason to abstract from them. Our primary reason is that there exist other policy instruments, such as the general level of and structure of taxation, which allow the government to influence the average level of output while, at the same time, being much less well-suited for the achievement of stabilization objectives, since they cannot be adjusted quickly and precisely in response to shocks.

It thus makes sense to assume that, in an optimal policy regime, the other instruments are chosen to achieve the desired average level of output for a given monetary policy, while the monetary policy rule is chosen to minimize those contributions to deadweight loss that are independent of the economy’s average level of output. We do this by choosing the monetary policy rule that maximizes W under the assumption that the other instruments are adjusted in the manner stated in response to any change in the monetary policy rule.

Abstracting from these effects also has the advantage of making our results independent of a feature of our model about which we are especially uncomfortable, namely its predictions about the effects of sustained inflation upon the long-run level of output. One might think that sustained inflation should result in adaptations that eliminate any effects of the average inflation rate upon average output. One such adaptation would be price commitments that specify a constant rate of price increase of n* between the occasions upon which the commitments are modified, as assumed in Yun (1996). With this modification, our model would come to satisfy the “natural rate hypothesis”. In the modified model, the correct second-order approximation to W would be exactly the one that we report here, but then it would apply to small fluctuations in the rate of inflation around any average value 7Г*.


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### Grant McDermott

Economics.
Environment.
Data science.

So, my PhD programme began today. We're starting with a preparatory maths and statistics course, before getting into the core modules $$-$$ micro, macro, 'metrics and (scientific) methods $$-$$ during the year. Well, those plus a couple of electives that I'm interested in taking, but won't mention here because they don't begin with the letter "m". Alliteration uber alles!
Anyway, after umming and ahhing for a while about the whole PhD palaver, I'm pretty happy with my decision to go this route. At this (very) early stage, I'm not particularly set on a career in academia afterwards $$-$$ though I certainly like having the option $$-$$ but rather feel the additional qualifications will stand me in good stead for my general career ambitions. Plus, I've been lucky enough with my research scholarship that my earnings won't really suffer in the interim :)
As a general comment, I believe that time away from studies and working in the professional sector certainly helped sharpen my focus coming into postgraduate studies $$-$$ as did my travelling stint. I know that some people happily go all the way through from a Bachelor's to a Doctorate, but I'm very pleased to have had those experiences outside of academics in retrospect. FWIW, I'd recommend a similar approach if anyone is seeking advice towards that end. Your perspectives are broader at the same time as your true interests are clearer. And, although the charge is often made unfairly, you're also far less likely to suffer from ivory-tower syndrome, which is the Achilles Heel of many university residents.


text:
# How to specify an ion source such as 90Sr for a simulation?

i want to use an ion such as 90Sr for a project to do a simulaiton,
how shauld i do?

Dear @Newconcept_1979,

you can define an radioactive isotope as a source using the ISOTOPE particle type on the BEAM card, in conjunction with the HI-PROPE card. Furthermore, you need to activate the radioactive decay with the RADDECAY card (semi analogue mode), and associate the scorings with a DCYSCORE card.

For an example see slide 24 of the following lecture:

@ amario,thanks!


text:
# Thanos.sh

This command could delete list half your files randomly.

don’t use it at home and other places. this is a real gun, use it wisely…

feel free to post your story on

1. 此脚本只会列出当前目录一半的文件。并且。。。总之小心点。。。

## Invoke-Thanos.ps1

Invokes Thanos to remove each object with probability 1/2. It works with files, registry, environment variables, functions, variables, aliases and certificates.

For help, use Get-Help .\Invoke-Thanos.ps1. Be sure to not actually invoke it!


text:
main-content

## Weitere Artikel dieser Ausgabe durch Wischen aufrufen

01.11.2016 | Ausgabe 1/2017

# Complete mappings and Carlitz rank

Zeitschrift:
Designs, Codes and Cryptography > Ausgabe 1/2017
Autoren:
Leyla Işık, Alev Topuzoğlu, Arne Winterhof
Wichtige Hinweise
Communicated by C. Mitchell.

## Abstract

The well-known Chowla and Zassenhaus conjecture, proven by Cohen in 1990, states that for any $$d\ge 2$$ and any prime $$p>(d^2-3d+4)^2$$ there is no complete mapping polynomial in $$\mathbb {F}_p[x]$$ of degree d. For arbitrary finite fields $$\mathbb {F}_q$$, we give a similar result in terms of the Carlitz rank of a permutation polynomial rather than its degree. We prove that if $$n<\lfloor q/2\rfloor$$, then there is no complete mapping in $$\mathbb {F}_q[x]$$ of Carlitz rank n of small linearity. We also determine how far permutation polynomials f of Carlitz rank $$n<\lfloor q/2\rfloor$$ are from being complete, by studying value sets of $$f+x.$$ We provide examples of complete mappings if $$n=\lfloor q/2\rfloor$$, which shows that the above bound cannot be improved in general.

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