July 2014
Beginner to intermediate
456 pages
11h 26m
Japanese
Content preview from 戦略的データサイエンス入門 ―ビジネスに活かすコンセプトとテクニック
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.
170
6 章 類似度、近傍、クラスタ
6.3
類似度と近傍に関連する重要な技法の詳細について
6.3.1
異質な属性
ここまでは、ユークリッド距離を使い、その計算が容易であることを示してきました。も
し属性が数値であり、しかも直接比較可能であれば、距離計算は本当に単純になります。し
かし、インスタンスに複雑で異質な（
heterogeneous
）属性が含まれている場合は、話はよ
り複雑になります。同じ業務分野で、もう少し属性が多い事例を検討してみましょう。
属性
A
さん
B
さん
性別 男性 女性
年齢
23 40
現住所在住期間
2 10
住居タイプ（
1
＝持ち家、
2
＝賃貸、
3
＝その他）
2 1
収入
50,000 90,000
複雑化を引き起こす要因が何点か現れました。まず、ユークリッド距離の式は数値式であ
り、性別はカテゴリカルな（離散的であり、記号で表現される）属性であることです。これ
は数値に変換する必要があります。
2
値であれば、「男性
=0
女性
=1
」のような単純な変換で
十分でしょう。しかし複数の値を持つカテゴリカルな属性の場合、これでは不十分です。
数値ではあるけれども、全く異なるスケールと値域を持つ属性があることも重要なポイン
トです。年齢が
18
から
100
の範囲となる一方で収入は
10
ドルから
10,000,000
ドルの範囲
になります。スケーリングを行わない場合、収入で
10
ドルの差が出ることと年齢で
10
の差
が出ることはユークリッド距離では同じ結果になり、これは良くありません。このため、最
近傍ベースのシステムは数値のスケーリング機能を備えています。このような機能は値の範 ...
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.