Drove growth for early-stage startup· Designed and developed Tracking system via cross-browsing fingerprinting· Improved valid tracking rate and reduced Customer Acquisition Cost by over $100Designed and developed Complex UI for Tax accountants.· Inline editing with Vue.js· Web-based Javascript Spreadsheets with Handsontable· Imported/exported password protected excel files and PDF filesManaged accounting data in Django· Converted labor cost information into printable formats and dispatched via fax· Supported binary format financial statements for communication with the National Tax ServiceDeveloped wrappers for a web application on both iOS and Android platformsMigrated an existing vanilla javascript chat application to Vue.js

[DeepNatural AI Annotation Tool, April 2019 - May 2019]Developed the annotation tool for AI data labeling using Vue.js[LG Digital Signage Total Care Service, Aug 2018 - April 2019]Developed remotely digital signage management system including all screen, content, settings through the website using Vue.js[Icepick, Jul 2018 - Sep 2018]Built a mobile app with React NativeDesigned and developed in-app purchases for iOS with React Native and handled unfinished consumable transactionsDeveloped url-based caching system for image and audio that similar with iOS caching system [Pixpills—Alternative to Behance, May 2018 - Nov 2019]Developed a file management system· Uploaded files to S3 using multipart methods· Managed access permissions and controlled cache validity periods· Cleared cache for presigned S3 objects using hashes instead of parameters to prevent browser cache errors[DallnSocuri—Interior content-driven e-commerce , Apr 2018 - Nov 2018]Integrated a web based payment system into a React native mobile app and a websiteBuilt a web based hybrid mobile app with React Native[WishTrend—Cross-border cosmetic e-commerce, Apr 2018 - Jun 2018]Made payment gateway modules(Paymentwall, Eximbay) for PrestaShop using PHP[LG Digital Signage Total Care Service, Sep 2017 - Dec 2017]Anomaly pattern data processing using pyspark with data frames· Collected statistics for each metrics every 3, 30, 90 days· Managed on-demand hadoop clusters in Azure HDInsight and DataFactory V2· Queried data from Azure Storage Account—compatible HDFS[Puddlr—messaging service for teams, Aug 2017 - Mar 2018]Support messaging with multiple teams using DjangoBuilt a desktop application with Electron to integrate custom desktop notifications and the file systemSet up a test automation with Selenium

[CAS thermometer]Showed a mesh network structure of low powered devices and tracked BLE beacon using D3.js force layoutDeveloped a multi-platform mobile application communicating with low powered thermometer using React native[Keywert—Searching for patents] (Dec 2015 – Apr 2016)Designed and developed complex UI using React.js· Created a table with dynamic columns, that can be added, removed, arranged and sorted· Searched query builder that can add a row that contains query information—field, and/or, keyword, etc.Made dynamic trees with animations to help understand the structure of the patent using D3.jsComplex query using Eleasticsearch

[LG Digital Signage Total Care Service, May 2014 - Aug 2014]Designed and developed Complex UI for managing digital signage devices· Inline editing with AngularJS 1.x· Composed hierarchy treesBuilt a restful API server using Django[AnySupport iOS—Remote support client for iOS, Sep 2014 - Apr 2015]Renewed and enhanced an existing application with navigation-based UIDeveloped multi-language support, drawing feature on the screen, and sharing feature system information profileDeveloped a websocket proxy server for the legacy server on top of Python asyncioCommunicated with the dedicated server in TCPCaptured and shared a screen periodically

Designed and developed a dedicated game server on top of Python asyncio· Communicated with a unity client using protocol buffer· Processed game resources from csv with metaprogrammingImproved performance of waiting queuesDeveloped a asyncio-compatible mysql pool libraryResolved a web socket connection issue over 3G network on O2 in the UK

Gala Lab is a game developer with focus on developing MMORPG games. Rappelz, a game developed by Gala Lab, has been serviced in 59 countries including Korea, North America, Europe, Russia, Mid-East. The company won the 10 million USD export tower in 2010 by the Korea International Trade Association.Developed a multithreaded server in C++ for the MMORPG game, Rappelz· Analyzed and debugged thread and lock system on the grid-based tile and resolved 700+ crash dumps and classified them into 6 main categories and 103 sub categories· Implemented game play features—PvP, Item enhancement, 15 character classes and their skills, set items, etc.To optimize MSSQL tables where frequent insert and delete operations occur, debounced status updates to reduce number of queries and reused rows from a managed set of unused rows. As a result, status update queries were reduced by 40%Designed and developed database caching using compare-and-swap operation implemented by getset command of RedisDeveloped a monitoring tool to track the status of distributed game servers behind firewalls and to call RPCs using the apache zookeeper