Tuesday, March 13, 2018

Simple note for Julia DataFrame


On this article, I'll write down the Julia's basic dataframe manipulation.
I just started to use Julia. I want to continue to use this language as DS and ML tool. For that, at first I'll focus on the basic dataframe manipulation.
Here, the version of Julia is 0.6.2.

Sunday, March 4, 2018

Try Julia: from install to simple mathematical operation

I started to use Julia. Although more or less one year ago, I touched Julia, it didn't become my daily tool. But these days I frequently hear about Julia in data science field and also the news about version 1.0 hit on me. So, I decided earnestly to tackle with it.
On this article, I'll arrange some information of Julia and show some mathematical and matrix operations.

Thursday, March 1, 2018

Some Fine tuning models with Keras: vgg16, vgg19, inception-v3 and xception


On this article, I'll try four image classification models, vgg16, vgg19, inception-v3 and xception with fine tuning. With Keras, we can easily try this.
About fine tuning itself, please check the article below.
The purpose of this article is to understand the points of fine tuning by doing some fine tuning models at once.

Wednesday, February 28, 2018

How Regularization works


On this article, I'll write about regularization.
Regularization is important method to prevent from overfitting and used in many algorithms. If I try to write accurately in good manner, it will be so long article. So here, I don’t stick to mathematical accuracy so much and in rough way I’ll try to show the system.

As a different approach to overfitting, Dropout is also nice. About this, please check the article below.

Tuesday, February 20, 2018

Simple Bayesian Modeling on Edward by Hamiltonian Monte Carlo


On this article, I'll re-write by Edward the simple bayesian model that was written on Stan.
This time, my target is from the following article.
Actually, I already wrote the article, Simple regression by Edward: variational inference. There, I re-wrote the model on Edward. But at that time, I used variational bayesian method for inference.
Stan uses Hamiltonian Monte Carlo. So, this time, I'll use Hamiltonian Monte Carlo on Edward and re-write the model.

Monday, February 19, 2018

Bayesian prediction interval from pystan output

On this article, I’ll leave the simple memo to get bayesian prediction interval from the sampled points of PyStan output and visualize it.
Basically, I’ll use the code from the article, Simple Bayesian modeling by Stan.

Sunday, February 11, 2018

Nice video for time series data analysis on Python

These days, I have watched some videos about time series analysis. I'll write here about one of my recommendations.
Roughly, the video is about time series data manipulation on Python, to say more concretely, on Pandas.

On this video, you can know
  • how to deal with time stamp data type
  • simple time series data processing
Those are fundamental and necessary knowledges to deal with time series data on Python. This video lets us know those manipulation on Pandas.
If you are new to time series analysis on Python, you can get the knowledge about basic manipulation by this video.

Friday, February 9, 2018

Slack bot for image stylization by magenta


With magenta and Slack’s Bots application, I made an image style change bot.
This works as following gif.

enter image description here

When we post the image to the bot, it adds the style to the image and posts the images to the slack channel.

Tuesday, January 30, 2018

How to make the local level model with seasonal effect


On time-series analytics, we frequently need to think about a recurring pattern. In the context of time-series analytics, a recurring pattern is referred to as a seasonal effect.

For example, please see the image below. This image is the plotting of a time series data. As you can see, it has recurrent pattern.

enter image description here
On this article, I'll make the local level model with seasonal effects on Stan.

Monday, January 29, 2018

Simple trial of various types of time series analytics

By air passengers data, which is typical time-series data, I'll try some time-series analytics methods. Actually, about some points, I'm not sure if it is really appropriate or not. So, if you find some wrong or incorrect points, please let me know.