DEV Community: Umitomo

Weekly Dev Log 2026-W03

Umitomo — Tue, 28 Apr 2026 06:21:07 +0000

🗓️ This Week

Finally finished the Cyber Security 101 learning path and discovered the AI Security Learning Path on TryHackMe
Completed 2 rooms from the AI Security Learning Path this week
Decided to continue working on the SwiftUI tutorial (also explored React Native with Expo out of curiosity)

📱 iOS (SwiftUI)

Ran unit tests for badge unlocking logic and stepped through them using breakpoints
Researched the differences between SwiftUI and React Native (with Expo) to determine the best platform for my learning

🌐 Web Development

Posted my weekly learning and development log on Dev.to📝

🔐 Security (TryHackMe)

Completed 2 rooms from the AI Security Learning Path on TryHackMe (AI Models & Data, Prompt Engineering)

💡 Key Takeaways

Learned how to use the po command and the map function in the console during debugging
Chose SwiftUI to focus on native iOS development (compared to React Native with Expo)

TryHackMe Learning

AI Models & Data

Learned that most AI models rely heavily on Common Crawl, a large public dataset collected from the internet
Realized that unclear data provenance and hidden sensitive data can lead to security risks
Learned that training decisions can impact security, including potential data leakage
Understood that optimization techniques introduce trade-offs between efficiency and security
Learned that fine-tuning inherits risks from base models such as bias and unsafe behavior
Realized that models are black boxes and difficult to fully audit
Learned that model cards are important but often incomplete

Prompt Engineering

Learned that LLMs process text as tokens and generate probabilistic outputs
Learned how parameters like temperature and top-p affect responses
Learned that effective prompts require clear instructions, context, format, and constraints
Understood the difference between system prompts and user prompts
Practiced prompt techniques such as zero-shot, few-shot, and Chain-of-Thought

🚀 Next Week

Continue working on the badge algorithm (Section 5) in the SwiftUI tutorial
Continue posting small articles on Dev.to
Continue working on the AI security Learning Path

Weekly Dev Log 2026-W02

Umitomo — Wed, 22 Apr 2026 07:24:49 +0000

🗓️ This Week

📱 iOS (SwiftUI)

Worked on the SwiftUI tutorial and completed Section 4 (Create an algorithm for badges)
Built a test file to verify the badge algorithm
Created unit tests for badge unlocking logic using an in-memory SwiftData container
Ran unit tests and stepped through them using breakpoint

🌐 Web Development

Posted my weekly learning and development log on Dev.to

🔐 Security (TryHackMe)

Completed OWASP Top 10 2025: Insecure Data Handling on TryHackMe
Worked on the AI/ML Security Threats room and completed Tasks 1–4

💡 Key Takeaways

Learned how to use MARK: comments for code organization
Understood the difference between insert and save, and how to isolate business logic from the UI
Reviewed how to inspect variable values during debugging
Learned how SSTI can lead to server-side code execution
Understood the difference between Base64 encoding and actual encryption
Reviewed the basics of AI/ML
Learned how LLMs work

🚀 Next Week

Test the badge algorithm and complete the SwiftUI tutorial section
Continue posting small articles on Dev.to
Continue working on the AI security learning path

Weekly Dev Log 2026-W01

Umitomo — Fri, 17 Apr 2026 07:22:41 +0000

🗓️ This Week

📱 iOS (SwiftUI)

Worked on the SwiftUI tutorial and completed Section 4 Steps 9–12 (Create an algorithm for badges)

🌐 Web Development

Started posting articles on Dev.to
Managing my articles using GitHub and GitHub Actions

🔐 Security (TryHackMe)

Completed OWASP Top 10 2025: IAAA Failures and Application Design Flaws on TryHackMe

💡 Key Takeaways

Learned basic state management through implementing a badge system in SwiftUI
Building a habit of posting regularly is important for consistency
Application design flaws can lead to serious security vulnerabilities
Relearned how to check port status using nc and Nmap in Bash
Learned how to send POST requests using curl
Learned how to decrypt data using OpenSSL
Understood the difference between Base64 encoding and AES-128-ECB encryption
Learned how to use Gobuster

🚀 Next Week

Test the badge algorithm implementation
Continue posting small articles on Dev.to
Complete the remaining OWASP challenge rooms

Hello Dev.to!👋 I'm starting my journey as a developer🌱

Umitomo — Wed, 15 Apr 2026 02:52:20 +0000

👋 Hello Dev.to!

Hi, I'm Umitomo 🐠 from Japan 🇯🇵

I work as an in-house systems engineer, mainly focusing on IT infrastructure and security.

💼 What I do

In my daily work, I handle IT infrastructure and security operations.

Outside of work, I enjoy building things as a hobby and have been learning:

SwiftUI (iOS development)
Web development (Remix, Cloudflare)
Cybersecurity (TryHackMe)

🚀 What I'm building

🌐 Web Development

I built a personal blog using Remix + Cloudflare + microCMS.

Since I plan to publish articles on Dev.to, I'm thinking about turning it into a portfolio site using React Router v7.

📱 iOS Development

I'm currently learning SwiftUI through tutorials.

I'd love to build apps that I can enjoy with my kids.

🎯 Why I'm here

I chose Dev.to because:

I want to challenge myself to write in English
I like the culture where it's okay to share not only tutorials but also personal learning journeys

I feel it's a great place to grow as a developer while sharing my progress.

✍️ What I’ll write about

My journey from infrastructure to development
Development logs and technical notes
Security learning and experiments

🌱 My goal

I'm starting small, but I want to stay consistent and keep learning step by step.

🙌 Nice to meet you!

Feel free to connect with me!