Re: [Gzz] 25th, 26th, 27th & 28th (hh)

[Tuomas Lukka]

> > > -For research questions a, b, and c, I know what the p2p field has to
> > offer: the
> > > best effort is DHTs with O(log n) (with small variations).
> > 
> > Again: with what assumptions? Who has to be trusted? How reliably is a
> > block
> > going to be found?
> 
> For normal conditions, with n nodes, the DHT algorithm require O(log n) hops 
> to
> reach arbitrary destinations *and* each node must mantain information about
> O(log n) neighbours. Additionally, DHT is very robust for failures; for 
> example,
> when 20% of the nodes simultaneously fail, less than 0.1% of the routes fail.

Routes, but what about blocks and finding them?

> The biggest problem in DHTs is that there might be hostile nodes which route
> requests purposely to wrong directions. However, there are proposal how these
> kinds of issues could be solved.

Well, these you must describe.

> > Does this work also with the "local store" model?
> 
> What do you mean by "local store" (replication or something else) ?

I mean: for each node, how much capacity should it allocate to the P2P network?
I.e. if everyone has 50MB of P2P data that they *WANT* to store and allocate
2MB for data that the algorithm wants to store, what happens? Does only the 2MB
get really used by others?


> >> -For e, there are some proposals, e.g. SQL-like searchs in DHTs and keyword
> >> searchs. However, this is quite Gzz specific, e.g. Urn-5 etc. (?)
> 
> >Urn-5: think about it as a very unique keyword. 
> 
> What do you mean by saying (in research questions): "Mist? tied?n, mik? on
> *suht* oikea ?" --> the word "suht".

How do I know, if starting just from the *words* "Helsinging sanomat", which
urn-5 and which key are the right ones? To distinguish between real and 
fake newspapers.

> > > -For f, same algoritmical limits hold true in this too. 
> > 
> > Which ones?
> 
> Now, look answer above.

Transclusions referring is not quite the same as the above: there are more
transclusions per document than urn-5's per document.
This is essentially a distributed database.

> > > This is also Gzz
> > > specific and is, at least someway, implentation issue when we have the
> > basic
> > > infrastructure builded (a, b, c)
> > 
> > It is similar to c) but not the same.
> 
> That's true, but (of course) same algorithmical limits applies also in this 
> case.

You haven't really made clear the algorithmical limits, their *exact* 
requirements
etc.

This is what you should probably work on most intensively: make really exact
definitions of what the different algorithms can mathematically do, based on
what assumptions.

> > > -For g and h, same as f (?)
> > 
> > Not a satisfactory answer.
> 
> Hmm...in practise, what g and h mean ?

Explain; what don't you understand?

You should probably start writing the actual results chapter right now,
because it's easy to put in the introduction etc. afterwards.

        Tuomas