As the non-fungible token (NFT) market grows, the movement to collect digital art works is increasing. NFTs are created to make forgery and tampering impossible by storing ownership of digital files on a blockchain. Currently, the most actively traded blockchain network for NFTs is Ethereum. However, in the current Ethereum, it has the inconvenience of creating and transacting non-fungible tokens once at a time. In this thesis, we propose a system that links NFTs created in the Ethereum network in a parent-child relationship and transmits a large amount to different accounts in two transactions. To this end, when parent NFTs are sent to other accounts by adding parent-child relationship properties as a smart contract based on Token ID, we examine the efficiency of using network fees through the process of sending child NFTs at the same time. Through this, the possibility of executing item trading in the game in an efficient way was identified from before the account that owns a large amount of NFT. In addition, it was proved that transmitting multiple NFTs in two transactions is more efficient than transmitting more than 8 NFTs individually, and there is a 60.04% gas cost saving effect when 745 NFTs are transmitted.

2021 Hanwha Line Blockchain Hackathon - Platform planning that can expand from the issuance of NFT certificates and the issuance of the first edition to the resell area for the prevention of used transaction fraud. - As a project lead, designed Business flow and token usage with service token and NFT. - Received an Excellence Award for ‘Luxury Used Trading NFT Relay Platform: Blimit’ Tryout: https://bit.ly/3IZscga Final: https://bit.ly/3GfhMYc Article: https://bit.ly/3Hri1AL Final Pitch: https://bit.ly/3ok8Ydv

ETHCON Korea is a non-profit Ethereum developer conference based in Korea - Supports Ethereum's open source decentralization philosophy - Aims to expand the base of the Ethereum development ecosystem - Following the precedent of domestic Pycon Korea, the Ethereum developer ecosystem want to expand As a member of an organizer, managed speakers and presentation materials,Sponsor Booth and registration 2019: https://bit.ly/3gnFBme 2020: https://bit.ly/34lk2Ai

Operated Ether Research Group in Korea, where we gathered various spec of developers and economists. As a moderator, I operated tech research Consensus Algorithm(BFT-based), Project research, Zero knowledge proof (ZKP). Also studied about token economy via Game Theory and mechanism design. With those research our team managed to go deep dive in Casper FFG and governance in blockchain. As a result, I have contributed deep knowledge about Blockchain core in Korea. You can check two major report and our seminar result. Consensus in Distributed System: https://bit.ly/3APpbMG Cryptoeconomic analysis Casper FFG: https://bit.ly/3s752Os 3rd: https://bit.ly/3geU7wD 4th: devstamp.io 5th: https://bit.ly/3gmzoqo 6th: https://bit.ly/3ghDmkd

Shinhan Group Hackathon , 2nd Price -Topic: simple payment service -contents: Enables simple payment by automatically analyzing personal delinquency according to asset status. -Purpose: Increasing the credibility of customers in banks through simple payment service Article: https://bit.ly/3L9R5rz