報告者は、「アカデミア／コミュニティとの橋渡し」というミッションの下グリーにおいて、研究会や大学と関わる業務を行っている。グリーは現在、SNS とソーシャルゲームの2 本立ての事業を行なっており、この事業形態へ発展してきた背景には、グリーの業務転換を恐れない戦略がある。また、現在のグリーを支える開発体制においては、職場環境などが大きく影響しており、月曜朝会などを継続している部分に強みがあるといえる。そのような中で、今後のインターネットサービスにおいては公共財としてのSNS が求められていくであろう。

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OZED is an educational virtual soccer robot construction kit that enables users creating their own soccer agent which is able to connect official RoboCup soccer simulation servers. A new kind of user interface system KONOHEN fuzzy was introduced and developped. That is a resoning with fuzzy set on multidimensional arbitrary shape.

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Superinstruction is well-known techniques of improving performance of interpreters. Superinstructions eliminate jumps between VM operations (interpreter dispatch) and enable more optimizations in merged code. In past, processors with simple BTB-based branch predictors had high misprediction rate when executing interpreted code, resulting in high overhead of interpreter dispatch, so superinstructions were used to reduce it. However, this assumption is incorrect for Ruby on current hardware. Accordingly, using superinstructions for eliminating jump instructions only marginally improves performance. In this paper, we consider applying superinstructions differently to improve performance of floating point computation. We note that high percentage of objects allocated during numeric computation are boxed floating point values, meanwhile garbage collection takes significant part of the execution time. Using superinstructions composed from pairs of arithmetic operations we were able to reduce allocation of boxed floats by up to 36%, and obtain improvement in performance of up to 22%.

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Superinstruction is well-known techniques of improving performance of interpreters. Superinstructions eliminate jumps between VM operations (interpreter dispatch) and enable more optimizations in merged code. In past, processors with simple BTB-based branch predictors had high misprediction rate when executing interpreted code, resulting in high overhead of interpreter dispatch, so superinstructions were used to reduce it. However, this assumption is incorrect for Ruby on current hardware. Accordingly, using superinstructions for eliminating jump instructions only marginally improves performance. In this paper, we consider applying superinstructions differently to improve performance of floating point computation. We note that high percentage of objects allocated during numeric computation are boxed floating point values, meanwhile garbage collection takes significant part of the execution time. Using superinstructions composed from pairs of arithmetic operations we were able to reduce allocation of boxed floats by up to 36%, and obtain improvement in performance of up to 22%.

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ソフトウェアへの機能追加のために実装の大規模な刷新が必要になることがある．実装刷新において後方互換性を完全に保つのは難しく，作業の途中で頓挫する例が後を断たない．実装刷新に失敗すると，開発プロジェクトでは巻き戻しの作業が発生するだけでなく，実装刷新を担当した開発者がモチベーションを欠き，長期的な生産性低下に繋がる恐れがある．本論文では，オープンソース開発における実装刷新の失敗事例を調査し，共通の要因とその対処法を明らかにした．調査の有効性を示すために，世界中に膨大な数のユーザを抱えるソフトウェアGNU Emacsの暗号化サブシステム(約4500行)に関して，提案手法に従って刷新を行なったところ，作業を円滑に完遂できた．

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Operating system (OS) reboots are an essential part of updating kernels and applications on laptops and desktop PCs. Long downtime during OS reboots severely disrupts users' computational activities. This long disruption discourages the users from conducting OS reboots, failing to enforce them to conduct software updates. Although the dynamic updatable techniques have been widely studied, making the system “reboot-free” is still difficult due to their several limitations. As a result, users cannot benefit from new functionality or better performance, and even worse, unfixed vulnerabilities can be exploited by attackers. This paper presents ShadowReboot, a virtual machine monitor (VMM)-based approach that shortens downtime of OS reboots in software updates. ShadowReboot conceals OS reboot activities from user's applications by spawning a VM dedicated to an OS reboot and systematically producing the rebooted state where the updated kernel and applications are ready for use. ShadowReboot provides an illusion to the users that the guest OS travels forward in time to the rebooted state. ShadowReboot offers the following advantages. It can be used to apply patches to the kernels and even system configuration updates. Next, it does not require any special patch requiring detailed knowledge about the target kernels. Lastly, it does not require any target kernel modification. We implemented a prototype in VirtualBox 4.0.10 OSE. Our experimental results show that ShadowReboot successfully updated software on unmodified commodity OS kernels and shortened the downtime of commodity OS reboots on five Linux distributions (Fedora, Ubuntu, Gentoo, Cent, and SUSE) by 91 to 98%.

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Memory deduplication improves the utilization of physical memory by sharing identical blocks of data. Although memory deduplication is most effective when many virtual machines with same operating systems run on a CPU, cross-user memory deduplication is a covert channel and causes serious memory disclosure attack. It reveals the existence of an application or file on another virtual machine. The covert channel is a difference in write access time on deduplicated memory pages that are re-created by Copy-On-Write, but it has some interferences caused by execution environments. This paper indicates that the attack includes implementation issues caused by memory alignment, self-reflection between page cache and heap, and run-time modification (swap-out, anonymous pages, ASLR, preloading mechanism, and self-modification code). However, these problems are avoidable with some techniques. In our experience on KSM (kernel samepage merging) with the KVM virtual machine, the attack could detect the security level of attacked operating systems, find vulnerable applications, and confirm the status of attacked applications.

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Recently, ubiquitous Internet-access services have been provided by Internet service providers (ISPs) by deploying wireless local area networks (LANs) in public spaces including stations, hotels, and coffee shops. The IEEE802.1X protocol is usually used for user authentications to allow only authorized users to access services. Then, although user personal information of access locations, services, and operations can be easily collected by ISPs and thus, their strict management has been demanded, it becomes very difficult when multiple ISPs provide roaming services by their corporations. In this paper, we present an anonymous IEEE802.1X authentication system using a group signature scheme to allow user authentication without revealing their identities. Without user identities, ISPs cannot collect personal information. As an efficient revocable group signature scheme, we adopt the verifier-local revocation (VLR) type with some modifications for use of the fast pairing computation. We show the implementation of our proposal and evaluation results where the practicality of our system is confirmed for up to 1, 000 revoked users.

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Recently, ubiquitous Internet-access services have been provided by Internet service providers (ISPs) by deploying wireless local area networks (LANs) in public spaces including stations, hotels, and coffee shops. The IEEE802.1X protocol is usually used for user authentications to allow only authorized users to access services. Then, although user personal information of access locations, services, and operations can be easily collected by ISPs and thus, their strict management has been demanded, it becomes very difficult when multiple ISPs provide roaming services by their corporations. In this paper, we present an anonymous IEEE802.1X authentication system using a group signature scheme to allow user authentication without revealing their identities. Without user identities, ISPs cannot collect personal information. As an efficient revocable group signature scheme, we adopt the verifier-local revocation (VLR) type with some modifications for use of the fast pairing computation. We show the implementation of our proposal and evaluation results where the practicality of our system is confirmed for up to 1, 000 revoked users.

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We propose a HMD (head mounted display) -based wearable AR (augmented reality) system that switches details of annotation information according to user's body motion such as walking and running, as a first step toward a more powerful and flexible context-aware AR system. Our body motion recognition algorithm uses a pair of accelerometers attached on user's thighs and recognizes five types of body motion -sitting, standing, walking, running and biking- as a user context by using a support vector machine. Through experimental studies with a prototype system, it was confirmed that the main concept of body motion-based information detail switching is widely accepted and that the recognition algorithm mostly functions as expected, though a few issues were identified that need to be improved such as a low running state recognition rate.

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