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
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293
293
10.6 Bag-of-Words を超えて
「
Department of the Interior
」（米内務省）、「
Game of Thrones
」（ゲーム・オブ・スローン
ズ）
†
は固有の意味を持つ特徴的なフレーズですが、それぞれを構成する個々の単語はまた
別の意味を持ち、かつ、それほど特徴的ではないかもしれません。しかし、それらがある特
定の順に並んだ時、ユニークな表現となり、固有の意味を持つようになるのです。基本的な
bag-of-words
では（あるいは
N-gram
であっても）このような固有の意味を認識できないた
め、どのような場合に単語の連なりが固有の意味を持つことになるのか、それを判断できる
コンポーネント（構成要素、部品）が必要になってきます。
多くのテキスト処理ツールキットは何種類かの固有表現抽出機能を備えています。通常、
これらの機能は生のテキストに対して処理を行い、人物や組織のような注釈付きでフレー
ズを抽出します。先に正規化が行われることもあり、そのような場合は「
HP
」、「
H-P
」、
「
Hewlett-Packard
」はすべて「
Hewlett-Packard Corporation
」のような一般的な表現に関連
付けられます。
空白や句読点で区切られたテキストをベースとする
bag-of-words
や
N-gram
と違い、固有
表現抽出は知識集約型と言えるでしょう。固有表現抽出がうまく作用するためには、大規模
なコーパスを用いた学習や、広範囲にわたる知識（固有表現）を手作業で登録していく必要 ...
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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.