App on Seunghoon Choi

Dual-Task Input and Decision Training: Practice Thinking During Fast Input

Sun, 12 Jul 2026 00:00:00 +0000

Free installable web app (PWA)

Dual-Task Input and Decision Training

The app measures input speed and decision accuracy separately, then compares them with performance when both tasks are combined.

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When a user speeds up number-key and mouse input while judging a new visual situation, choosing the next action can become harder. Hand speed alone does not explain this problem. The user selects an input sequence while also judging the situation. When those choices overlap, selecting the next action can take longer. This app does not score input speed alone. It also measures the decision performance that remains during input.

Korean Typing Practice: From Keyboard Basics to Citizenship Essays

Sun, 28 Jun 2026 00:00:00 +0000

Installable web app (PWA)

Korean Typing Practice

From keyboard key drills to typing citizenship essay model answers, one step at a time.

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I built this so my wife could practice typing the citizenship essay model answers herself. You don’t need to be familiar with the Korean keyboard; you don’t even have to switch your computer’s input to Korean. The screen tells you the next key to press and which finger to use.

ReadFast: English and Chinese Meaning-Unit Reading Practice

Tue, 16 Jun 2026 00:00:00 +0000

Installable web app (PWA)

ReadFast: English and Chinese meaning-unit reading

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First, register the English or Chinese text you want to read. ReadFast uses that text for a training session and adds the same text to the Texts tab with its original and a natural Korean translation. The training screen presents the text in short connected units, so you can keep linking meaning as you read.

Korean Citizenship Comprehensive Evaluation Practice - Written, Essay, and Oral Mock Training

Sun, 14 Jun 2026 00:00:00 +0000

Installable web app (PWA)

Korean Citizenship Comprehensive Evaluation Practice

Practice the written, essay, and oral sections repeatedly in one place.

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I started building this while my wife was preparing for Korean citizenship. Written questions, essay topics, and oral practice materials were scattered everywhere, so I built one place where she could practice them repeatedly. No payment, no sign-up.

Written practice - repeat multiple-choice questions until they feel familiar
Essay and oral practice - look at expected topics and practice writing or speaking your own answers
Korean-Chinese side-by-side text - easier for users who are still building Korean fluency
Installable web app (PWA, Progressive Web App) - add it to your phone’s home screen and use it like an app, even offline

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