February 2015
Intermediate to advanced
200 pages
4h 48m
Japanese
Content preview from Bluetooth Low Energyをはじめよう
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Bluetooth Low Energyをはじめよう
特 性 値またはディスクリプタの 書き込みはセキュリティパーミッションにしたがって行われる。
コネクションのセキュリティレベルが確立された要件にマッチしない場合（081ペ ー ジ の「 セ
キュリティ」を参照）、サーバーは書き込みを拒否する。
サーバー主導更新
サーバー主導更新（Server-initiated updates）は 、サ ー バ ー か ら ク ラ イ ア ント へ 非
同期的に（つまり、クライアントの要求に対する応答としてではなく）送信され得る唯一の
パケットだ。このような更新によって、クライアントが定期的にポーリングしていなくても特
性値に変更があったという警告をタイムリーに送信できるので、電力と帯域幅の両方を節
約 することができる 。
サーバー主導更新には2種 類ある。
• 特性値通知（Characteristic Value Notification）
通知（Notification）は、特性値アトリビュートのハンドルと、その現在の値とを含むパ
ケットだ 。これを受 信したクライアントはそれ に 基 づ いた 行 動を起こすことが できるが 、受
領確認のアクノリッジをサーバーへ返すことはない。応答なしの書き込み以 外 で は 、こ
れが ATT の標準的な要求／応答フロー制御メカニズムにしたがわない唯一のパケットで、
サーバーはこの通知を任意の時点で任意の数だけ送信することができる。この機能は
ハンドル値通知（
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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.