Bitcoin Forum
June 19, 2021, 03:50:00 PM *
News: Latest Bitcoin Core release: 0.21.1 [Torrent]
 
  Home Help Search Login Register More  
  Show Posts
Pages: [1] 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 ... 151 »
1  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: January 25, 2017, 11:57:55 PM
Thank you all for your continued interest. Regrettably, I do not have time to maintain this list into the future.

I would edit a disclaimer into the first post that this list dates from 2014 and is hence quite out of date, but the forum software is not allowing me to. I will preserve the post for historical purposes.
2  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: March 06, 2015, 09:24:07 PM
Shouldn't Ukyo/WeExchange be in here as well?

https://bitcointalk.org/index.php?topic=337523.0

Thanks. I'll have time again come this Sunday, so I'll put up an update then.
3  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: January 09, 2015, 09:28:08 PM
There was a theft from poloniex almost a year ago. A percentage of BTC was stolen. So poloniex subtracted from everyone's balances the percentage and finally payed back after some months all the coins from the fees.

I am just writing this in case you are interested and want to research it more. 

The amount stolen (77 BTC) was below the cutoff, so this won't be included. A cutoff provides an objective way to include or exclude thefts.
4  Economy / Speculation / Re: Time-series analyses on: January 07, 2015, 02:37:37 AM
Unfortunately, I've lost the code to generate this model and the backtest results. If I remember right, the R2 was marginally lower than that of an exponential trend, which means that the model is probably marginally less accurate than an exponential extrapolation. The graph in the OP is roughly accurate so far only by coincidence.

  • Treat the logarithm of the time series as a function with domain [0, π).
  • Detrend the dataset.
  • Fit the function as a linear combination of sin(x), sin(2x), sin(3x), etc. to the desired precision.
  • Extrapolate this to the domain [π, 2π).
  • Retrend the dataset and remove the logarithm to get predicted price values.
  • Multiply by the "depression factor" to correct predicted price values so as to be consistent with today's price.

Since this algorithm has no skill, I feel comfortable sharing it as a curiosity. Does anyone else have any similar failed models that nevertheless produce interesting results?

You mean you changed the entire domain available at the time to [0, π)? Or do you change every year to [0, π), or something like that?

If it's the first, how do you refit the model as more data becomes available? Do you set the entire domain to [0, π) every time?

The "depression factor" bothers me. You mean, your model yields an expected price, which you have to change to current price?

Instead of doing that, try creating a model for the differences in price. That way, you won't need any depression factor. See the first model in my signature for an example.

Yes, I agree that the "depression factor" is not at all desirable. Also, you are correct that the refits require compressing the domain, and so even a minor refit can produce a significant change in the model. The only benefit of the model seems to be that the price movements look more natural than the other ones I've tried, with only negligible loss of skill. I will look at your model when I have time.
5  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: January 06, 2015, 09:36:07 PM
Thanks to everyone who has mentioned something. I am aware that coverage of 2014 is very incomplete, and hope to expand it soon. Once the Bitstamp incident becomes more clear I will put up an update including it at least.
6  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: January 05, 2015, 09:50:06 PM
There's some Bitstamp drama right now. In particular this address seems to contain stolen coins.

https://blockchain.info/address/1L2JsXHPMYuAa9ugvHGLwkdstCPUDemNCf
7  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: December 03, 2014, 09:42:25 PM
What about the two relatively recent dice sites that absconded with investor dunds, Dice Ninja and Dice Bitcoin?

Surprised they aren't here, because they seem to meet the criteria for inclusion. Anyway, great record OP.

Thanks, noted. They may show up in one of the next updates, which will hopefully not take too long.
8  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: November 16, 2014, 12:23:29 AM
BASIC-MINING and MintPal have been added. Preliminary estimates for the Mt. Gox loss are up too. I'm still behind on the backlog though; hopefully I can get a few more updates in before my schedule tightens up again.

Huobi has been in the news. I'm not sure if this is an actual theft or a misunderstanding. Can any Chinese users help clear this up?

I also plan to move from January 2014 BTC to a more recent benchmark, probably July 2014 BTC (this is better psychologically, since many of us don't remember what the price was in January). This will hopefully go smoothly.
9  Economy / Speculation / Re: Milestones on: October 14, 2014, 10:24:28 PM
I think it's time to bump this thread.
I'm betting 0.05 BTC we just passed 398 for the last time.


I really enjoyed this thread last year.  This year?  Well not yet anyways!  Hopefully you are right about passing 398 for the last time.  I agree that chances are we are only moving upwards from this point on.

Well, looks like we're back under 398 due to a small selloff. So it's good that Adrian didn't shake on the bet yet Wink.
10  Bitcoin / Bitcoin Discussion / Re: List of Major Bitcoin Heists, Thefts, Hacks, Scams, and Losses on: October 03, 2014, 09:14:24 PM
I have seen this in the news recently:

http://www.ibtimes.co.uk/chinese-bitcoin-exchange-huobi-loses-5000-btc-1-2m-blunder-1467192

I will take some time over the weekend to do some more research and finally post a (long-delayed) list update.
11  Economy / Speculation / Time-series analyses on: September 28, 2014, 11:33:17 PM
I was conducting some time-series analysis on Bitcoin/USD when I stumbled on this algorithm, which produced the following prediction:



I don't claim the algorithm has much skill (based on this dataset, it seems to perform almost as well as a simple exponential trendline, which is not surprising since the algorithm is just noise added to an exponential trendline). But I am impressed at how natural the price movements predicted seem. The chart looks nice Cheesy.

The algorithm is fairly simple:

  • Treat the logarithm of the time series as a function with domain [0, π).
  • Detrend the dataset.
  • Fit the function as a linear combination of sin(x), sin(2x), sin(3x), etc. to the desired precision.
  • Extrapolate this to the domain [π, 2π).
  • Retrend the dataset and remove the logarithm to get predicted price values.
  • Multiply by the "depression factor" to correct predicted price values so as to be consistent with today's price.

Since this algorithm has no skill, I feel comfortable sharing it as a curiosity. Does anyone else have any similar failed models that nevertheless produce interesting results?
12  Economy / Speculation / The bubble popped in winter; could this year end red? on: September 28, 2014, 09:29:26 PM
Historically, Bitcoin has always been up on December 31 relative to January 1 of the same year.

But these dates are arbitrary. There have been long periods of time in 2012, for example, where Bitcoin price was below where it was a year ago.

However, because a winter bubble pop has inflated January's numbers, this may be the first time that the price will not recover in time to colour 2014's candle green. (The price on January 1 was $745.)

Thoughts?
13  Other / Meta / Re: [Request] Ban "Posted From bitcointalk.org Android App" on: September 22, 2014, 08:16:40 PM
Signatures that are not in the signature line are banned.

I understand they are discouraged but not banned. Do you have a reference for that?

This post from theymos clarifies that only valedictions or names are discouraged. All other signatures are banned:

Yeah, that's not allowed. Any signature must be in the signature area. (Except that a traditional valediction or just your name is allowed, though this is discouraged.)

I removed the existing ones. Anyone who continues posting them will be banned.
14  Other / Meta / Re: [Request] Ban "Posted From bitcointalk.org Android App" on: September 22, 2014, 07:20:20 PM
Who really cares. Why waste everyones time on such a small matter.  The app works great, who cares if they advertise a little.

Signatures that are not in the signature line are banned. Otherwise there would be little point in signature size limitations. This allows people to turn off signatures if they wish. A forum is a place for discussion, and extra stuff is a distraction from that.
15  Economy / Speculation / Re: Bitcoin price cannot fall infinitely on: September 19, 2014, 02:29:09 AM
I disagree that Bitcoin price cannot decrease further, because miners are a very small proportion of Bitcoin sellers.

But I'm currently bullish and believe that we're near a minimum.
16  Other / Meta / Re: Activity & new membergroup limits on: August 31, 2014, 02:26:53 AM
The max at the moment is Hero member wonder if the admins and mods will consider adding a higher level?

They already have (Legendary). It comes sometime before 1000 activity (slightly randomized for each user).
17  Other / Meta / Re: Activity & new membergroup limits on: August 21, 2014, 10:05:46 PM
This current activity system was in place last Christmas. In addition, 1500 is more than enough activity to be a Hero Member. You must have gotten dates mixed up somewhere.

The dates are correct.  I don't remember exactly how many posts I had but it was a lot cause many people were commenting on it. 

I think the old system also had a time variable - where you had to be logged on for a certain number of hours and unlike now, it took a long time to accrue just 1 single day.  So maybe I wasn't hero yet due to the time constraint which took a while to accumulate.

I don't remember exactly but I am certain I was Senior level and was very close to HERO cause I was looking forward to it and I am also certain I lost it all just cause I went on vacation.

And if you look at my post history from the beginning, I was not posting 2 word spam posts, I was simply very active.  I posted long hours everyday just to have it taken away without any warning.

I should easily be a legendary member now yet I'm still not even a hero member. 

The system put in place has always been like this and has not changed since it was implemented, in June last year. This can be confirmed with a search on the Wayback machine, or perhaps the below quote from Meni Rosenfeld:

time = number of two-week periods in which you've posted since your registration
activity = min(time * 14, posts)
I don't like it.

It embodies the assumption that any post above once per day (averaged over two weeks) is not contributing; which I do not agree with.

At the very least number of posts per day should be increased, e.g. min(time * 28, posts).

And you should consider more sophisticated metrics such as sum of f(x) over all two-week periods, f(x) being x / (1 + sqrt(x/14)) or x / (1 + x/28).

Time spent logged in will also be useful to include as a component.
18  Other / Meta / Re: Activity & new membergroup limits on: August 21, 2014, 09:52:30 PM


I have had several periods when I received more than 14 points in one single 2 week period.  Does anybody know how I did that or how that happened?  Clearly the 14 points variable has other options but I have never seen anything discussed about it.

Does anybody know anything about this?  Thx.

Regards...

i got 28 in just 4 days  Huh

This is a quirk of how the system works. The two week periods are global; that is, they aren't related to your account's age, but rather a fixed epoch. You registered three days before a shift in two-week periods, so the forum believes you to have posted in two 2-week periods, and hence caps your activity at 28. Since you have more than 28 posts, that's why your activity is 28.



This activity system has always been the activity system, replacing a raw post count system. There has been no rule change since its implementation.


That simply cannot be true.

I went on vacation last Christmas at the Sr. Level with activity of nearly 1,500 and post count of nearly 1,500 and I came back after about 3 weeks with the same post count but my activity dropped massively to a lousy Jr. member level.  I was days away from becoming HERO and I had to start over but this time adding activity points become way more difficult.

So clearly, the activity algo was changed in a big way; I know this for a fact cause I had to start over 8 months ago and I'm still not where I was before I made the mistake of taking a little time off.

This current activity system was in place last Christmas. In addition, 1500 is more than enough activity to be a Hero Member. You must have gotten dates mixed up somewhere.

Also, taking a little time off is not really detrimental to your activity, as it can't decrease unless posts are deleted. However, taking time off does increase how long it will take to reach a certain activity level.
19  Other / Meta / Re: Activity & new membergroup limits on: August 21, 2014, 09:46:23 PM
I find it annoying how you can be like a couple activity off of a rank, such as 56 activity, and you are just 4 off of member.

its stupid.

I agree.  After this next period I'm gonna be 4 points off hero.  I wish I could gain those 4 points this period.

I'm guessing this is happening because we had our accounts going before the new rule took place late last year.

I really wish there was a legit way for people to gain some extra points.  Something challenging so account farms wouldn't be able to do it.  Those of us who put in the extra effort every single day should be rewarded somehow more than those who farm accounts and add little to no value to this forum.  

Cause right now we are rewarded activity points equally which is in no way fair to some of the more active, legit members.

This activity system has always been the activity system, replacing a raw post count system. There has been no rule change since its implementation, which was definitely not "late last year", but rather in June.
20  Bitcoin / Development & Technical Discussion / Re: Is the wiki incorrect about length of addresses. on: August 21, 2014, 01:56:16 PM
0000000000000000000000000000000000000000
1111111111111111111114oLvT2

27 characters

0000000000000000000000000000000000000001
11111111111111111111BZbvjr
26 characters

This fact always surprises people. Wink

Another related surprise is that version-zero addresses are on average longer than version-one addresses, due to Satoshi's inefficient encoding of the zero byte. The only exceptions are those addresses with multiple leading zeroes.
Pages: [1] 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 ... 151 »
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!