April 2020
Intermediate to advanced
344 pages
8h 22m
Japanese
Content preview from Pythonではじめる教師なし学習 ―機械学習の可能性を広げるラベルなしデータの利用
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
8.7
線形活性化関数を用いた過完備オートエンコーダ
187
8.7
線形活性化関数を用いた過完備オートエンコーダ
次に過完備オートエンコーダの問題点を見てみよう。過完備オートエンコーダは、入力層や出力層よ
りも多くのノードがある隠れ層を持つ。ニューラルネットワークの容量（
capacity
）が 大 き い の で 、 訓 練
対象の観測点を記憶できてしまう。
つまり、このようなオートエンコーダは恒等関数を学習してしまうのだ。これは最も避けなければな
らないことだ。このようなオートエンコーダは、訓練データに対して過剰適合してしまい、不正なトラ
ンザクションを真正のトランザクションと区別する役には立たない。
訓練セットのクレジットカードトランザクションの重要な側面だけを学習することで、真正のトラン
ザクションがどのようなものかを学習し、正常でなくまれな不正トランザクションの情報を記憶しない
ようなオートエンコーダが必要だということを思い出そう。
訓練セットの情報の一部を失うことができるオートエンコーダだけが、不正なトランザクションを真
正のトランザクションと分離することができるのだ。
model = Sequential()
model.add(Dense(units=40, activation='linear',input_dim=29))
model.add(Dense(units=29, activation='linear'))
このオートエンコーダの損失を下に示す。また、図8-5に、平均適合率、適合率 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.