The First Cry of Atom Today is the first day of the rest of my life.

Forget grief, keep data

Three years ago, I walked around Shinjuku at Tokyo. I had not yet obtained informal decision from current company for which I now work. So I walked around Shinjuku for job hunting as pre-graduate student called “Shukatsu-sei” in Japanese. First I wondered what happened. Then I escaped from the building shook violently. In spite of the pleasant ... Read more

Difference between PCA and dA

Today I gave a presentation about Deep Learning in my office. Through this presentation, I felt the difficulty of explanation about mathematic notion without equations. Complex concept should be attached with some equations. Simplicity was one of the biggest purpose of my presentaion. Anyway, there is a question I cannot answer clearly. Wha... Read more

Logistics Regression with Sparse Vector

In my project I have to develop a model that is capable of predicting the count of page view from sparse vector data such as [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] However I found it was difficult to make a model which can be applie... Read more

Memento pattern in Java

Recently, I implemented some design patterns following this book. This book introduces 23 design patterns that all programmers should know when you write according to OOP instructions. So now I want to write this article about some of these patterns and explain these. All codes that used in this article are put here What is Memento pattern? ... Read more

How is HashMap written in Java

Here recently, I have a chance to read Java core API, expecially HashMap. Usually, I use HashMap paying no attention to, but this code reading brought many things to me. I can understand that how HashMap is written in Java and more this is very simple than I expected. So in this post, I’d like to introduce some ideas and code used in java.util.H... Read more