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  Niobio Cash Improvement proposal
  NCIP: 7
  Title: Reduction of Emission Speed Factor
  Author: Helder Garcia <helder.garcia@gmail.com>
  Status: Draft
  Type: Standards
  Created: 2018-05-01
  License: PD

Table of Contents

Abstract

This NCIP describes a change to the emission speed factor, which will reduce the block reward, after a hard fork.

Motivation

  1. Current curve of emission of the currency is too fast for support the objectives of the project. After its fifth year, the emission would be more than 91%.
The figure below shows emission curve for emission speed factor 18, considering situation from block 82130, mined on April, 30th 2018.

After the change to speed factor 20, the curve will be like the following:

Specification

Emission speed factor regulates the reward the miner receives for a given block mined. To reduce the reward this factor will be increased from current value of 18 to a new value of 20.

Implementation

The snippet below shows how the reward is calculated.

if (blockMajorVersion >= BLOCK_MAJOR_VERSION_5) {
  baseReward = (m_moneySupply - alreadyGeneratedCoins) >> m_emissionSpeedFactorV5;
} else {
  baseReward = (m_moneySupply - alreadyGeneratedCoins) >> m_emissionSpeedFactor;
}

where m_emissionSpeedFactorV5 is 20, used after the hard fork to block version 5. Before that, value 18 from m_emissionSpeedFactor is used.

Base reward is derived from remaining supply of coins, subtracting total supply from previously generated amount of coins. To the result of this subtraction, a right shift is applied where the number of positions to shift is denoted by the emission speed factor.

Taking block number 82130 the generated coins at that time was 90375038.84349324 NBR. From total supply of 336000000, the remaining coins still to be mined are 245624961.15650676 NBR.

This number, without the decimal point, converted to binary is showed below. The 18 bits delimited in brackets are removed by the 18 bits right shift operation.

1010111010000110111010111000111110001[010011000001110100]

The remaining bits converted to decimal and with the decimal points in place give the reward for next block (82131): 936.98486769 NBR.

Considering the new emission speed factor of 20, the calculation of the next block reward is:

10101110100001101110101110001111100[01010011000001110100] = 234.24621692 NBR.

Activation

To create consensus among the network about the new block reward calculation, a voting window of 240 block will moves continually until 85 percent of the blocks are signaling with the upgrade. After the threshold of 85 percent is reached, a LOCKED_IN phase of 50 blocks will run before the blocks upgrade to version 5. Then blocks version 4 will be rejected.

Copyright

This document is placed in the public domain.