Author Topic: suggestion to witnesses on "the highest one" CNY price feeding model  (Read 19921 times)

0 Members and 1 Guest are viewing this topic.

Offline roelandp

  • Full Member
  • ***
  • Posts: 114
  • Witness, dad, kitesurfer, event organiser
    • View Profile
    • RoelandP.nl
  • BitShares: roelandp
  • GitHub: roelandp
the way i see it that markets are always on the move. every witness is running pricefeed scripts monitoring the markets. this should be as accurate as possible sand have certain treshold when to update parameters in place. some witnesses run updates at fixed intervals, others whenever price changes by x percent or a combination of both. pricefeeds are always reactive to the market and some witnesses respond faster or frequenter then others  or have different parameters for example in weight of individual exchanges. this leaves to differences in published feeds and that is something which is when dealing with this living organic oracle a good thing I think. because the ultimate pricefeed is taken from the median any anomalities are equalled out, provided enough witnesses are running correct pricefeedscripts.

that said, i will give a look whether my markets-to-monitor portfolio is still accurate.
clockwork suggested about cointiger. i will add that one asap.

currently looking at https://roelandp.nl/bitshareswitnesslog/ i see my feed for CNY diverges 1.7% from the current median: (1.27 vs 1.25) which I think is perfectly within bounds.

on my aforementioned page, pricefeeds with divergence of more than 5% off median are reported in red as well as outdated pricefeeds

update: to chime in on the “markets always moving statement”: now im looking 1 hour later at my feed and see a difference of 0.9% from the median (1.24) in my published feed at 1.25.

note that the page caches results for 15 minutes.
« Last Edit: August 11, 2018, 10:57:26 am by roelandp »

Offline bitcrab

  • Committee member
  • Hero Member
  • *
  • Posts: 1926
    • View Profile
  • BitShares: bitcrab
  • GitHub: bitcrab
the fed price from several witnesses are obviously lower than it should be. as marked red in the pic.

at the time of the snapshot, in DEX the price is above 0.815CNY.

hope the marked witnesses can upgrade the price feeding scripts in time.

Email:bitcrab@qq.com

Offline bitcrab

  • Committee member
  • Hero Member
  • *
  • Posts: 1926
    • View Profile
  • BitShares: bitcrab
  • GitHub: bitcrab
reply to several comments:

"the highest one" model surely cannot prevent the debt position from being margin called, earlier or later, what the new model can bring is:

1. it makes more difficult for shorters to do the "targeting selling to make margin calling", I believe this kind operation will disappear if the new model can be applied by most of the witnesses.

2. previously some abnormal low price appear and make some position margin called, which actually should not happen, for example, last year when polo stoped BTS deposit/withdraw, this happened several times. the new model can prevent this events from happening.

the harm of fed price bias to longers(debt position owner) and shorters are asymmetric,when lower bias happen, longers are hurt by margin calling, when higher bias happen, nothing happen to shorters, they can go to the exchange with highest price and sell BTS.

the margin call rule is designed to release risk in time, not to provide chance for shorters to make profit, definitely the rule should be more friendly to longers.

the BTS/bitCNY pair in DEX has the biggest volume of BTS on the earth, and it's easy to do bitCNY/fiat CNY conversion, so it's a reliable price data source, and adopt "the highest one" bring no problem, if the highest price is too high than that in other exchanges, arbitrator will pull it down rapidly.
Email:bitcrab@qq.com

Offline sschiessl

  • Administrator
  • Hero Member
  • *****
  • Posts: 662
    • View Profile
  • BitShares: sschiessl
我反对!
我支持增加bitcny的发行量,但是不是靠采取最高喂价来实现!
一是最高喂价更容易作弊以及弄虚作假;
二是即使采用了最高喂价,且所有喂价都合理,则等到爆仓单压下来的时候,一样是该爆掉的爆掉。这样做最多只是缓解了一下而已,将来的结果无非是再给空军送一次韭菜!

Please open a Chinese thread in the respective section of.this forum.

Offline gmgogo

  • Sr. Member
  • ****
  • Posts: 333
    • View Profile
我反对!
我支持增加bitcny的发行量,但是不是靠采取最高喂价来实现!
一是最高喂价更容易作弊以及弄虚作假;
二是即使采用了最高喂价,且所有喂价都合理,则等到爆仓单压下来的时候,一样是该爆掉的爆掉。这样做最多只是缓解了一下而已,将来的结果无非是再给空军送一次韭菜!

Offline sschiessl

  • Administrator
  • Hero Member
  • *****
  • Posts: 662
    • View Profile
  • BitShares: sschiessl
Can we keep this important discussion English please?

Offline Yao

  • Hero Member
  • *****
  • Posts: 534
    • View Profile
  • BitShares: yao
  • GitHub: imYao
Suggestion was not for core to use MAX of price feeds...core would still use median...suggestion was for individual pricefeeds to take the max between CEXs and DEX...
The more I think about, the more merits I can find in this approach. Still, I do not think we can weight DEX and CEX equally, we should stick with *VOLUME* and than it is no different than
considering the DEX as much an exchange as any other too, from point of view of the feed produer

Firstly, a note, volume can be faked.

As of writing, among all CEXs, Poloniex's BTS/BTC market has the best market depth (which IMHO is liquidity), around 2M BTS on each side (aka walls) near the center.

Depth of all other CEXs are far less, for example, ZB.com's BTS/USDT market has only 200K BTS on the book near the center.

However, according to CoinMarketCap (https://coinmarketcap.com/currencies/bitshares/#markets), Poloniex only produced 2% of total volume, while ZB produced more than 20%, not to mention that LBank has even less BTS on the book but generated more total volume.

Another metrics is total BTS hold in their wallets, which should be somehow positively correlated to volume. From https://cryptofresh.com/ballots, we can see Poloniex has 187M BTS in their wallet and generated 3M daily volume, ZB has around 45M and generated around 20M daily volume. LBank? I don't even know which account is theirs. I guess I'll change my price feed script to weight price by this metrics.

I'd say price on Poloniex is realer than ZB or LBank. With deeper depth on the book, it's harder to push the price up or down.

However, who knows whether the amounts on the book are real? The big walls could be (and likely are) set by one person, in this case he can cancel it at any time and push the price towards any direction when he wants.

To get a stabler price, we need to make market, say, put up real buy and sell walls on the centralized exchanges. Anyway, there are many risks involved if to do so.

Another option is to make market in the DEX. We have OpenLedger, Gdex, CryptoBridge and etc are actually same as CEXs, we can put up walls there, produce volumes there. No, don't count in bitAssets markets, they're derivatives, their value need to be calculated out thus hard to be used directly.

I am totally agree with @abit

在数据不透明的中心化交易所,“量作假”很容易(刷量),“深度作假”也很容易(卖单卖的是白条,买单用的是假钱,可以随时撤单,不幸成交就是亏空,交易所会想办法弥补亏空),对于没有量也没有深度的交易所“价格作假”也很容易。

喂价需要一个可信赖的“真量”、“真深度”从而有“真价格”的市场,这样的市场只能在基于BitShares这样的区块链搭建的透明交易所里实现。同时 @abit 也提到不能依靠bitCNY(以及所有 SmartCoins)这类衍生品市场,衍生品的价格本身受影响因素较多(充提费率的人为设定因素、内外盘搬砖效率、市场波动频率和幅度、喂价脚本计算价格的策略和数据源的可信度……等),价格失真是常态。那就需要发展BitShares的网关资产(即UIA代币)市场,让BTS直接与“网关法币”(gateway Fait,Fait CNY/USD、……)和“网关加密资产”(gateway crypto-assets,XXX.BTC/ETH/EOS、……)进行交易产生可靠的市场价格,但需要解决的问题是UIA本身的透明度。

CryptoBridge在“网关加密资产”(gateway crypto-assets)的透明度方面做了很好的探索,用户充值BTC时发行(issue)等额的BRIDGE.BTC,而用户提现BTC时就销毁(burn)等额的BRIDGE.BTC,实际流通的BRIDGE.BTC与CryptoBridge网关托管的真实BTC是基本相同的,公开其网关的BTC地址即可证实其可靠性!

我们还需要解决的是“网关法币”(gateway Fait)的透明度和可靠性,有以下几种方式:
①银行账户背书的网关法币监管等政策风险较大,透明性则需要通过第三方审计等方式来证明其有100%真实法币进行背书,就像USDT。
②直接用USDT,虽然任何人都可通过区块链进行审计,但USDT本身是需要传统的第三方审计的。
③还有一种相对可靠方式:以bitCNY为100%备付金背书发行替代稳定货币,如XCNY,1XCNY=¥1.00。多签管理的备付金托管账户的bitCNY在BitShares链上可查,XCNY的流通量在BitShares链上也可查,这样透明性和可靠性都有保证。
« Last Edit: August 11, 2018, 03:43:34 am by Yao »

Offline johnson

  • Full Member
  • ***
  • Posts: 146
    • View Profile
the max price algorithm is for "BTS price", so if apply, should be applied to ALL smart coins. otherwise there should be enough gap (for price feed) between CNY and other smart coins. 

if apply to CNY only, will make bitCNY much cheaper according to real currencies.

The fact is,the bitcny is usually  expensive then RMB now.

Offline johnson

  • Full Member
  • ***
  • Posts: 146
    • View Profile
应该是外盘取平均,与内盘取最大,看内盘深度,如果到达某个理想深度,就取消外盘喂价

这样也可以,核心就是让暴力砸盘拉低喂价吃尸体的做法不再行得通。

这个太激进,不适合bitcny,可以拿bitjpy测试。

现在取消喂价还太激进。当bts有20亿都抵押的情况下,还可以尝试一下。不然分分钟被空军
把内盘砸穿

Offline bitcrab

  • Committee member
  • Hero Member
  • *
  • Posts: 1926
    • View Profile
  • BitShares: bitcrab
  • GitHub: bitcrab
one question, after we guarantee the basic fairness, should the business logic be more friendly to longers or shorters?

definitely longers, I think no need to explain more.

suppose now in poloniex the BTS price is 0.81CNY, in DEX it is 0.84CNY, highest in all the source, which price should be adopted as price?

if we need to be more friendly to longers, obviously 0.84 is the answer, if shorters think this unfair, OK, come to DEX and make the price down by selling.

yes, we need more money to come, eagerly, but at first we have to optimize the top design and the business logic continually, if the logic is always more friendly to shorters,  what new money dare to come?



« Last Edit: August 11, 2018, 12:23:07 am by bitcrab »
Email:bitcrab@qq.com

Offline abit

  • Committee member
  • Hero Member
  • *
  • Posts: 4651
    • View Profile
    • Abit's Hive Blog
  • BitShares: abit
  • GitHub: abitmore
Suggestion was not for core to use MAX of price feeds...core would still use median...suggestion was for individual pricefeeds to take the max between CEXs and DEX...
The more I think about, the more merits I can find in this approach. Still, I do not think we can weight DEX and CEX equally, we should stick with *VOLUME* and than it is no different than
considering the DEX as much an exchange as any other too, from point of view of the feed produer

Firstly, a note, volume can be faked.

As of writing, among all CEXs, Poloniex's BTS/BTC market has the best market depth (which IMHO is liquidity), around 2M BTS on each side (aka walls) near the center.

Depth of all other CEXs are far less, for example, ZB.com's BTS/USDT market has only 200K BTS on the book near the center.

However, according to CoinMarketCap (https://coinmarketcap.com/currencies/bitshares/#markets), Poloniex only produced 2% of total volume, while ZB produced more than 20%, not to mention that LBank has even less BTS on the book but generated more total volume.

Another metrics is total BTS hold in their wallets, which should be somehow positively correlated to volume. From https://cryptofresh.com/ballots, we can see Poloniex has 187M BTS in their wallet and generated 3M daily volume, ZB has around 45M and generated around 20M daily volume. LBank? I don't even know which account is theirs. I guess I'll change my price feed script to weight price by this metrics.

I'd say price on Poloniex is realer than ZB or LBank. With deeper depth on the book, it's harder to push the price up or down.

However, who knows whether the amounts on the book are real? The big walls could be (and likely are) set by one person, in this case he can cancel it at any time and push the price towards any direction when he wants.

To get a stabler price, we need to make market, say, put up real buy and sell walls on the centralized exchanges. Anyway, there are many risks involved if to do so.

Another option is to make market in the DEX. We have OpenLedger, Gdex, CryptoBridge and etc are actually same as CEXs, we can put up walls there, produce volumes there. No, don't count in bitAssets markets, they're derivatives, their value need to be calculated out thus hard to be used directly.
BitShares committee member: abit
BitShares witness: in.abit

Offline Thul3

  • Hero Member
  • *****
  • Posts: 574
    • View Profile
Can anyone explain to me why the urgent need to modify the feed price in favour of DEX if
bitcrab and everyone else can use now target CR and the so called margin call problem should be solved now ?

Or is it to stengthen future buy walls ?



Seriously explain it to us please as it looks for most people you trying to implement something which is not needed anymore for the claimed attacks.

Please provide transparancy



Also if you think a step further creating a higher BTS price via price manipulation on DEX than CEX which bitcrab is planing will lead that people will take these bitassets for selling BTS buy Assets they can trade on CEX like EOS,BTC,ETH etc which DEX is already leaking to sell it on CEX and buy back cheap BTS there.

So manipulating the price bitcrab is trying will only lead of a bigger liquidity issue of assets like EOS,BTC,ETH etc for a higher BTS price.

Is that really the goal of DEX?

I highly doubt that as this can be only solved via adoption and not via price manipulation
« Last Edit: August 10, 2018, 01:25:51 pm by Thul3 »

Offline binggo

  • Hero Member
  • *****
  • Posts: 2374
  • 世间太多瘪犊子
    • View Profile
Still you didn't answered why you don't say it directly that DEX is going to dictate the price feed ?
Why do you use the term "highest one" ?

Name it by the name DEX one.
no need discuss with you  ;)

Offline xeroc

  • Board Moderator
  • Hero Member
  • *****
  • Posts: 12922
  • ChainSquad GmbH
    • View Profile
    • ChainSquad GmbH
  • BitShares: xeroc
  • GitHub: xeroc
Suggestion was not for core to use MAX of price feeds...core would still use median...suggestion was for individual pricefeeds to take the max between CEXs and DEX...
The more I think about, the more merits I can find in this approach. Still, I do not think we can weight DEX and CEX equally, we should stick with *VOLUME* and than it is no different than
considering the DEX as much an exchange as any other too, from point of view of the feed produer

Offline clockwork

  • Committee member
  • Sr. Member
  • *
  • Posts: 376
    • View Profile
  • BitShares: clockwork
I think this is a problem that price feed scripts should address, rather than proposing to somehow change from median(price feeds) to max(price feeds) within the bitshares core.

If price feed publisher's scripts are overly reliant on BTC:BTS prices then they should be upgraded to sample multiple exchanges, accounting for trading volume (flagging suspected centralized manipulation) and sampling from many more alternative trading pairs such as USDT, ETH, mutliple internal bitshares market references (feed|market)..

With Max, if a single price feed publisher publishes 1000000 (or some other very high feed) then it would cause global settlement, where as median price feed would have been more secure from such an outlier price feed.

Suggestion was not for core to use MAX of price feeds...core would still use median...suggestion was for individual pricefeeds to take the max between CEXs and DEX...