October 2014
Intermediate to advanced
288 pages
6h 27m
Japanese
Content preview from 実践 機械学習システム
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クラス分類
III
：音楽ジャンル分類
173
9
章
クラス分類
III
：音楽ジャンル分類
これまで見てきた例では、訓練データをベクトル値で表現することは簡単に行えました。たとえば、
アイリスデータセットでは、花は特定部分の長さや幅などを含んだベクトルとして表現されていまし
た。テキストを扱った例では、テキストデータをbag-of-wordと呼ばれる表現に変換し、テキストの
内容を表現できる特徴量を自分たちで設計しました。
本章で扱う内容はこれまでとは異なり、音楽をジャンル毎に分類する問題を扱います。そのために
は、たとえば「長さ3 分の音楽をどのように表現したら良いか？」ということを考えなければならないで
しょう。MP3データをそのままビットとして扱うべきでしょうか？ または、テキストデータの時と同
じように“bag of sound bites”なるアプローチをとるべきでしょうか？ 答えは「ノー」です。仮にそ
のようなアプローチをとれば、複雑になりすぎ
て上手くいかないことでしょう。いずれにせよ、音楽
データをその特性を捉えることができる数値に変換しなければなりません。
9.1
本章のロードマップ
本章において、まともな分類器を作るためには、これまで学んだ知識以上のことが求められます。
ひとつにはサウンドベースの特徴量を用いなければなりません。それは以前考察したテキストベースの
ときよりも複雑になります。また、これまで分類問題は二値分類についてだけ考えてきましたが、今回
は多クラス（multiclass）への ...
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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.