# 1.2 Machine learning lecture 3  (Page 5/14)

So in the problem set we’re actually gonna let you play around more with this algorithm. So I won’t say too much more about it here. But to finally move on to the next topic let me check the questions you have. Yeah?

Student: It seems like you still have the same problem of overfitting and underfitting, like when you had a Q’s tow. Like you make it too small in your –

Instructor (Andrew Ng) :Yes, absolutely. Yes. So locally weighted regression can run into – locally weighted regression is not a penancier for the problem of overfitting or underfitting. You can still run into the same problems with locally weighted regression. What you just said about – and so some of these things I’ll leave you to discover for yourself in the homework problem. You’ll actually see what you just mentioned. Yeah?

Student: It almost seems like you’re not even thoroughly [inaudible] with this locally weighted, you had all the data that you originally had anyway.

Instructor (Andrew Ng) :Yeah.

Student: I’m just trying to think of [inaudible] the original data points.

Instructor (Andrew Ng) :Right. So the question is, sort of, this – it’s almost as if you’re not building a model, because you need the entire data set. And the other way of saying that is that this is a non-parametric learning algorithm. So this –I don’t know. I won’t debate whether, you know, are we really building a model or not. But this is a perfectly fine – so if I think when you write a code implementing locally weighted linear regression on the data set I think of that code as a whole – as building your model. So it actually uses – we’ve actually used this quite successfully to model, sort of, the dynamics of this autonomous helicopter this is. Yeah?

Student: I ask if this algorithm that learn the weights based on the data?

Instructor (Andrew Ng) :Learn what weights? Oh, the weights WI.

Instructor (Andrew Ng) :I see, yes. So it turns out there are a few things you can do. One thing that is quite common is how to choose this band with parameter tow, right? As using the data. We’ll actually talk about that a bit later when we talk about model selection. Yes? One last question.

Student: I used [inaudible] Gaussian sometimes if you [inaudible]Gaussian and then –

Instructor (Andrew Ng) :Oh, I guess. Lt’s see. Boy. The weights are not random variables and it’s not, for the purpose of this algorithm, it is not useful to endow it with probable semantics. So you could choose to define things as Gaussian, but it, sort of, doesn’t lead anywhere. In fact, it turns out that I happened to choose this, sort of, bell-shaped function to define my weights. It’s actually fine to choose a function that doesn’t even integrate to one, that integrates to infinity, say, as you’re weighting function. So in that sense, I mean, you could force in the definition of a Gaussian, but it’s, sort of, not useful. Especially since you use other functions that integrate to infinity and don’t integrate to one. Okay? It’s the last question and let’s move on

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
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