To provide event-driven services in IoT, scalable methods of topic-based pub/sub messaging are indispensable. Methods using structured overlay networks are promising candidates. However, existing methods have the problem of wasting network resources, because they lack adaptivity to “exhaust data, ” which have low or no value most of the time. The problem contains two aspects. One is that each publisher node continues to forward data to a relay node even if there are no subscribers. The other is that excessively large multicast trees are constructed for low value data, which will be received by only a small number of subscribers. In this paper, we formulate the desirable design of overlay networks by defining a property called “strong relay-free” as an expansion of relay-free property. The property involves publishers and subscribers composing connected subgraphs to enable detecting the absence of subscribers and autonomously adjusting the tree size. We also propose a practical method satisfying the property by using Skip Graph, and evaluate it through simulation experiments. We confirmed that the proposed method can suspend publishing adaptively, and shorten the path length on multicast trees by more than 75% under an experimental condition with 100,000 nodes.

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In the current rapidly changing business environment, companies need to be efficient and agile to survive and thrive. That is why flexible systems integration is urgent and crucial concern for any enterprise. For the meanwhile, systems integration technology is getting more complicated, and middleware types are beginning blur for decades. We sort system integration into four different types, “Delayed Federation", “Real-time Federation", “Delayed Integration", and “Real-time Integration". We also outline appropriate technology and architecture for each type.

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As distributed computing becomes part of the daily life of an expressive number of people, it becomes important to rethink the way we express compatibility between the components of distributed systems. This paper proposes a mechanism to check service compatibility based on service contracts. We propose that a contract should be specified in terms of a process calculus and that interacting services should have their algorithms verified against such contracts. This way, we can formally check if they can reach a target state, meaning that they can successfully interact. In order to guide the compatibility check we propose a variation of the Java programming language to create a Domain-Specific Language (DSL). This DSL, along with a run time model, was specially designed to allow for an automated examination of behavior in a message-oriented middleware environment. We provide a qualitative evaluation of our proposal through the analysis of an example involving the dynamic creation of interconnections.

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ユビキタスコンピューティング環境において，情報家電機器やセンサがネットワークに接続され，多様に遍在することになる．しかし誰が，それらの情報家電機器やセンサを抽象化するソフトウェアコンポーネント(部品)を組合せ，分散ユビキタスアプリケーションの構築を行うのかは差し迫った課題である．特に家庭内においては，ランニングコストや即時性の観点から，ユーザ自身により，それらのソフトウェアコンポーネント間を自由に構成する機構が不可欠である．本論文で，分散アプリケーションを複数種類のユーザインタフェースから構成できる独立型モデリングトポロジを提案し，それらを実現するミドルウェアuBlocksを提案する．

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本稿では、IoE時代のものづくりや様々なサービス領域でのシステムのデザイン・構築・運用に関するP２Mについて論じる。IoE時代のP２Mのためには、様々なマイクロサービスコンポーネントからなるシステムとそのオーケストレーションが課題となる。しかしながら今なおIoTのシステム開発のアーキテクチャとして用いられているものの多くは、クラウド上のデータベースソリューションである。だがそのシステムのデザインは、現場の能力開発や現場からの改善は否定され、トップダウンの計画化とシステム構築・運用がなされる。本発表ではそれとは異なる現場からのアーキテクチャデザインとマイクロサービスの視点から、システムデザイン・構築・運用に関するP２Mのスリーエスモデルを論じ、それがフォグコンピューティング領域での新しいIoEアーキテクチャと密接に結びつくことを論じる。

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