# 1.15 Machine learning lecture 16  (Page 13/15)

Other versions will cause V(s) conversion to be *(s). In synchronized updates, it makes them just a tiny little bit faster [inaudible] and then it turns out the analysis of value iterations synchronous updates are also easier to analyze and that just matters [inaudible]. Asynchronous has been just a little bit faster.

So when you run this algorithm on the MDP – I forgot to say all these values were computed with gamma equals open 99 and actually, Roger Gross, who’s a, I guess, master [inaudible] helped me with computing some of these numbers. So you compute it. That way you run value relation on this MDP. The numbers you get for V* are as follows: .86, .90 – again, the numbers sort of don’t matter that much, but just take a look at it and make sure it intuitively makes sense.

And then when you plug those in to the formula for computing, that I wrote down earlier, for computing p* as a function of V*, then – well, I drew this previously, but here’s the optimal policy p*.

And so, just to summarize, the process is run value iteration to compute V*, so this would be this table of numbers, and then I use my form of p* to compute the optimal policy, which is this policy in this case.

Now, to be just completely concrete, let’s look at that free one state again. Is it better to go left or is it better to go north? So let me just illustrate why I’d rather go left than north. In the form of the p*, if I go west, then sum over s prime, P(s, a) s prime, P*(sp), this would be – well, let me just write this down. Right, if I go north, then it would be because of that. I wrote it down really quickly, so it’s messy writing. The way I got these numbers is suppose I’m in this state, in this free one state. If I choose to go west and with chance .8, I get to .75 – to this table -- .75. With chance .1, I veer off and get to the .69, then at chance .1, I go south and I bounce off the wall and I stay where I am.

So that’s why my expected future payoff for going west is .8 times .75, plus .1 times .69, plus .1 times .71, the last .71 being if I bounce off the wall to the south and then seeing where I am, that gives you .740.

You can then repeat the same process to estimate your expected total payoff if you go north, so if you do that, with a .8 chance, you end up going north, so you get .69. With a .1 chance, you end up here and .1 chance you end up there. This map leads mentally to that expression and compute the expectation, you get .676. And so your total payoff is higher if you go west – your expected total payoff is higher if you go west than if you go north. And that’s why the optimal action in this state is to go west.

So that was value iteration. It turns out there are two sort of standard algorithms for computing optimal policies in MDPs. Value iteration is one. As soon as you finish the writing. So value iteration is one and the other sort of standard algorithm for computing optimal policies in MDPs is called policy iteration. And let me – I’m just going to write this down.

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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