【升級過後的 ETH2.0 代表著什麼？】
除了今年備受矚目的以太坊柏林升級以及 EIP-1559 提案之外，以太坊 2.0 的重大升級也是許多人一直以來引頸期盼的重點👀

究竟 ETH 2.0 升級代表著什麼呢？整體區塊鏈產業又有可能會有什麼樣的影響，讓幣研來告訴你

#cryptonewbie #cryptoanalysis #eth2.0

🟡 以太坊2.0的改進主要有以下重點

- 以太坊支援 Solidity 以外的程式語言做開發
- 透過分片技術大大提高交易速率
- 共識機制由工作量證明（PoW 轉為 PoS)

今年以太坊的柏林、倫敦以及預計十月分登場的上海硬分叉都是為了讓以太坊能夠進入2.0階段的預備措施，最終以太坊會進入代號「寧靜」（Serenity）的發展階段

以太坊2.0 的升級過程不是慢慢推進更新而成的，而是先把以太坊 2.0 的信標鏈建構好，再將以太坊1.0、2.0 合併而成

🟡 以太坊從 1.0 升級到 2.0 主要會經歷三大階段：

1. 信標鏈主網（Beacon Chain）：於 2020 年 12 月 1 日上線
2. 對接（The merge）：2021 年底
3. 分片鏈（Shard chains）2022 年

🟡 以太坊2.0 能夠解決什麼問題

- 進一步解決先前規模性的問題（scalability），提升整體運作效能
- 降低礦工門檻，只要質押32 ETH 就能夠成為驗證節點，使整體區塊鏈網路更加去中心化
- 同時提升安全性，因為驗證者違規將有可能失去抵押的以太幣

目前抵押於2.0智能合約的以太幣超過750萬枚，佔以太幣總流通量6.5%以上

雖然我們不能確定以太坊2.0 什麼時候才能升級完成，除了技術開發之外，也需要透過經濟手段迫使礦工逐漸轉往 PoS 模式，但是不管是在鏈上的運作效率以及整體的通縮手段上都有非常大的轉變，日後的推進必然也會是整體幣圈的焦點
-------------------------------------------------------------
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📜 [專欄新文章] Gas Efficient Card Drawing in Solidity

✍️ Ping Chen

📥 歡迎投稿： https://medium.com/taipei-ethereum-meetup #徵技術分享文 #使用心得 #教學文 #medium

Assign random numbers as the index of newly minted NFTs

Scenario

The fun of generative art NFT projects depends on randomness. The industry standard is “blind box”, where both the images’ serial number and the NFTs’ index are predetermined but will be shifted randomly when the selling period ends. (They call it “reveal”) This approach effectively solves the randomness issue. However, it also requires buyers to wait until the campaign terminates. What if buyers want to know the exact card right away? We’ll need a reliable onchain card drawing solution.

The creator of Astrogator🐊 isn’t a fan of blind boxes; instead, it thinks unpacking cards right after purchase is more interesting.

Spec

When initializing this NFT contract, the creator will determine the total supply of it. And there will be an iterable function that is randomly picking a number from the remaining pool. The number must be in range and must not collide with any existing ones.

Our top priority is accessibility/gas efficiency. Given that gas cost on Ethereum is damn high nowadays, we need an elegant algorithm to control gas expanse at an acceptable range.

Achieving robust randomness isn’t the primary goal here. We assume there’s no strong financial incentive to cheat, so the RNG isn’t specified. Implementers can bring their own source of randomness that they think is good enough.

Implementation

Overview

The implementation is pretty short and straightforward. Imagine there’s an array that contains all remaining(unsold) cards. When drawIndex() is called, it generates a (uniform) random seed to draw a card from the array, shortens the array, and returns the selected card.

Algorithm

Drawing X cards from a deck with the same X amount of cards is equal to shuffling the deck and dealing them sequentially. It’s not a surprise that our algorithm is similar to random shuffling, and the only difference is turning that classic algo into an interactive version.

A typical random shuffle looks like this: for an array with N elements, you randomly pick a number i in (0,N), swap array[0] and array[i], then choose another number i in (1,N), swap array[1] and array[i], and so on. Eventually, you’ll get a mathematically random array in O(N) time.

So, the concept of our random card dealing is the same. When a user mints a new card, the smart contract picks a number in the array as NFT index, then grabs a number from the tail to fill the vacancy, in order to keep the array continuous.

Tweak

Furthermore, as long as the space of the NFT index is known, we don’t need to declare/initialize an array(which is super gas-intensive). Instead, assume there’s such an array that the n-th element is n, we don’t actually initialize it (so it is an array only contains “0”) until the rule is broken.

For the convenience of explanation, let’s call that mapping cache. If cache[i] is empty, it should be interpreted as i instead of 0. On the other hand, when a number is chosen and used, we’ll need to fill it up with another unused number. An intuitive method is to pick a number from the end of the array, since the length of the array is going to decrease by 1.

By doing so, the gas cost in the worst-case scenario is bound to be constant.

Performance and limitation

Comparing with the normal ascending index NFT minting, our random NFT implementation requires two extra SSTORE and one extra SLOAD, which cost 12600 ~ 27600 (5000+20000+2600) excess gas per token minted.

Theoretically, any instantly generated onchain random number is vulnerable. We can restrict contract interaction to mitigate risk. The mitigation is far from perfect, but it is the tradeoff that we have to accept.

ping.eth

Gas Efficient Card Drawing in Solidity was originally published in Taipei Ethereum Meetup on Medium, where people are continuing the conversation by highlighting and responding to this story.

👏 歡迎轉載分享鼓掌

NT 430 特價中

學習如何使用 Ethereum 和 Solidity 從一個中心化的 MERN 應用程式製作一個去中心化的區塊鏈應用程式( Dapp )

https://softnshare.com/blockchain-development-convert-an-app-to-a-dapp/

I trimmed almost every piece of my soap, so I got a lot of soap scraps. Normally I'd put them into a new soap as confetti embeds or just rebatch. However, the solidity of soaps made from these methods are softer and melt quicker than the normal soaps.

Ways to reuse the soap scraps:
1. rebatch as floating soap👉https://youtu.be/Dodrv6UfyNw
2. confetti embeds👉https://youtu.be/CtQ8w3qkWnA
3. laundry powder👉https://youtu.be/DxR2Eom_ckM

Years ago, I learnt the method of blend the soap scraps with oil before mixing with lye from a Taiwan soaping group and the result was so perfect. I use the same technique in this batch and add some orange oil and orange colorant to create the beautiful look.

【配方/Recipe】
椰子油 coconut oil: 2800g
橄欖油 olive oil: 800g
棕櫚油 RSPO-certified palm oil: 400g
皂屑 soap scraps: 1400g
99%氫氧化鈉 sodium hydroxide: 664g
純水 distilled water: 1520g
橘子油 orange oil: 200g
橘珠光粉 orange colorant: 1大匙/tablespoon

The slab cutter is customized from an acrylic factory nearby and they don't ship...even domestically. I'm sorry for not able to provide you link to get one.


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+本編メイク動画はこちらから
cosmetics used can be found here.
http://godmake.me/movie/detail/1240/

フロムハンドメイクアップアカデミーによるhow to動画シリーズ！
GODMake.の人気モデル大坪愛ちゃんを海外セレブ風に変身させちゃう動画の２本目です♪
濃いギャルメイクは卒業して、オシャレなハーフ顔や大人ギャル顔になりたい！！と思っている女の子は必見！ギャルメイクとの微妙は違いをプロが細かくレクチャーしてくれているので
ぜひぜひ参考にしてみてね♪

「海外セレブ風！大人ギャルメイク②」フロムハンドメイクアップアカデミー
「海外名媛风！成熟GAL妆容②」Fromhand Makeup Academy
「Mature GAL Makeup After Overseas Celebrity！②」Fromhand Makeup Academy


+POINT1
上品なパールの入った、カーキとゴールドを足したアイシャドウをアイホール全体に入れます。
用带优雅珠光的卡其色金色眼影涂在整个眼睑上。
Apply khaki and gold eyeshadow with pearl lustre at the whole eyelids.

+POINT2
アイラインは目尻から入れます。目頭にたっぷりアイラインを引くと若い印象になってしまうので、目尻を少し長めに取り目頭はあとからプラスします。
眼线从眼尾开始画。眼头眼线画得太饱满会变成很年轻的形象所以眼尾画得长一些，眼头稍微加上一些即可。
Start eyeliner from the outer corner of eyes. If you draw the liner at the inner corner too thick, it will seem young, so draw a little long tail at the outer corner and add some at the inner corner.

+POINT3
軸の太いつけまつげでアイライン効果を出します。両端が取れやすいので丁寧につけましょう。
用轴粗一些的假睫毛能有眼线的效果。两端容易脱落因此要仔细贴上假睫毛。
False eyelashes with a thick wand can make effect of eyeliner. The boths ends come loose easily so apply them carefully.

+POINT4
茶とオレンジを混ぜた色を眉にのせます。
用茶色和橙色的混合色涂在眉毛上。
Apply mixed color from brown and orange at the eyebrows.

+POINT5
眉の内側にもパウダーをのせて立体感を出します。
眉毛的内侧也涂上眉粉来突出立体感。
Apply powder inside the eyebrows as well to emphasize the solidity.

+POINT6
マットなブラウンで目のホリを深く見せるためにWラインを引きます。
为了让眼窝看上去很深，用亚麻棕色来画双重眼线。
For making chiseled eyes, draw double line with matt brown eyeshadow.

+POINT7
更に眉の下のマットな白を入れます。
再在眉毛下方画上亚麻白色的眼影。
Then apply matt white eyeshadow below eyebrows.

More POWER by Makeup.
[ G O D M a k e . G l a m ] http://g-godmake.me/

いつもお世話になっております、
ミスターヒロの名レーサーたにでさんが来てくれました、
相変わらず素晴らしいマシーンさばき、
Performance naked
New Z1000 gave concrete "Performance" and "Control feeling" to the genre of the performance naked.
Tiger who takes a stance low, barks, and rages. Moreover, the forged muscular beauty to make the sprinter think is magnificent. New Z1000 on which it insists with Crautingstail must come. The impression appeals. To enjoy the trained performance the same as the impression freely, ..improvement Ryde.. position was selected. Layout from which position of foot rest is natural and is not tired. Please give the performance of ..installed muscularity.. Cou to ..muscularity.. body work skilled.


Four water-cooled DOHC in-line engines that boast of the high reliability that is succeeded by a great car of successive and raised are installed in "ZRX1200R". The torque of room is demonstrated in a wide rotation region, and handling that treats easily has been achieved though it is a Big motorcycle. A bikini caul with high effect of the rectification and mass glove rail for space of utility under the seat and the tandem is equipped normally though it is a small act. It ..room.. digests from the winding to the town youth and the tandem touring. Moreover, the theft control is equipped with an effective immobilizer, and the risk from the theft has been reduced. The appearance of solidity or more has been given by increasing the thickness of the tank emblem of the aluminum material in the model in 2008. The wheel color is obtained, and moreover, the black is obtained in "Lime green" and feeling of luxury and a sporty feeling by setting it to Gold and each color are obtained again in "Metallic Diablo black".