Once a software product has been released, a large number of software products may be derived from an original single product. Management and maintenance of product variants are important, but those are hardly cared because developers do not make efforts for the further maintainability in the initial phase of software development. However, history of products would be lost in typical cases and developers have only source code of products in the worst case. In this paper, we approximate the evolution history of software products using source code of them. Our key idea is that two successive products are the most similar pair of products in evolution history, and have many similar source files. We did an experiment to compare the analysis result with actual evolution history. The result shows 78% (on average) of edges in the extracted trees are consistent with the actual evolution history of the products.

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オープンソース開発においては，LinuxやApacheなどのいくつかのプロジェクトが成功を収めている．特に，Linuxにおいては，開発プロジェクト全体を統括できるリーダーが存在しているという特徴が指摘されている．しかしながら，オープンソースの開発手法においては，開発者は営利的な目的を有しておらず，相互に緩く結合されているため，プロジェクトの運営にあたっては，リーダーシップは必要ないという指摘もなされている．この二つの指摘は相互に矛盾するようにも思われる．本研究では，階層構造を有するエージェントモデルに基づき，オープンソース開発プロジェクトにおけるリーダーシップの効果について調査した結果を述べる．

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Research on intrusion-tolerant systems (ITSs) is being conducted to protect critical systems which provide useful information services. To provide services reliably, these critical systems must not have even a single point of failure (SPOF). Therefore, most ITSs employ redundant components to eliminate the SPOF problem and improve system reliability. However, systems that include identical components have common vulnerabilities that can be exploited to attack the servers. Attackers prefer to exploit these common vulnerabilities rather than general vulnerabilities because the former might provide an opportunity to compromise several servers. In this study, we analyze software vulnerability data from the National Vulnerability Database (NVD). Based on the analysis results, we present a scheme that finds software combinations that minimize the risk of common vulnerabilities. We implement this scheme with CSIM20, and simulation results prove that the proposed scheme is appropriate for a recovery-based intrusion tolerant architecture.

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Motivated by the deployment of post-disaster MANEMO (MANET for NEMO) composed of mobile routers and stations, we evaluate two candidate routing protocols through network simulation, theoretical performance analysis, and field experiments. The first protocol is the widely adopted Optimized Link State Routing protocol (OLSR) and the second is the combination of the Tree Discovery Protocol (TDP) with Network In Node Advertisement (NINA). To the best of our knowledge, this is the first time that these two protocols are compared in both theoretical and practical terms. We focus on the control overhead generated when mobile routers perform a handover. Our results confirm the correctness and operational robustness of both protocols. More interestingly, although in the general case OLSR leads to better results, TDP/NINA outperforms OLSR both in the case of sparse networks and in highly mobile networks, which correspond to the operation point of a large set of post-disaster scenarios.

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This paper proposes a protocol called νLIN6 which supports both network mobility and host mobility in IPv6. There are several proposals to support network mobility and host mobility. Network Mobility (NEMO) Basic Support Protocol has several problems such as pinball routing, large header overhead due to multiple levels of tunneling, and a single point of failure. Optimized NEMO (ONEMO) and Mobile IP with Address Translation (MAT) are solutions to provide route optimization, but they generate a lot of signaling messages at a handover. In νLIN6, packet relay is required only once regardless of the nested level in network mobility while optimal routing is always provided in host mobility. A fixedsized extension header is used in network mobility while there is no header overhead in host mobility. νLIN6 is more tolerant of network failure and mobility agent failure than NEMO Basic Support Protocol. It also allows ordinary IPv6 nodes to communicate with mobile nodes and nodes in the mobile network. We implemented νLIN6 on 2.0 Release. Our measurement results showed νLIN6 can provide host mobility and network mobility with low overhead.

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As a result of the rapid development of the Internet in recent years, network security has become an urgent issue. Distributed denial of service (DDoS) attacks are one of the most serious security issues. In particular, 60 percent of the DDoS attacks found on the Internet are TCP attacks, including SYN flood attacks. In this paper, we propose adaptive timer-based countermeasures against SYN flood attacks. Our proposal utilizes the concept of soft-state protocols that are widely used for resource management on the Internet. In order to avoid deadlock, a server releases resources using a time-out mechanism without any explicit requests from its clients. If we change the value of the timer in accordance with the network conditions, we can add more flexibility to the soft-state protocols. The timer is used to manage the resources assigned to half-open connections in a TCP 3-way handshake mechanism, and its value is determined adaptively according to the network conditions. In addition, we report our simulation results to show the effectiveness of our approach.

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The behavior of virtual machine (VM) programs are monitored by virtual machine monitors (VMMs) for security purposes. System calls are frequently used as a monitoring point. To monitor the system calls, the VMM inserts a breakpoint, called a hook point, into the memory of the monitored VM. The hook points are determined based on experimental knowledge. However, reading the source codes of operating systems (OSes) requires specialized knowledge. In addition, the appropriate hook point differs among OSes and OS versions. Analyzing the source code in each OS update is impractical. Searching for the appropriate hook point for various OSes is also difficult. To address these problems, we propose a method for estimating the hook point using a memory analysis technique. The proposed method acquires the memory of the monitored VM and then searches for an appropriate instruction appropriate to hook. The search instructions depend on the processor architecture. In addition, we also proposed a method for searching the appropriate instruction using a single step execution. This version reduces the cost for searching the instructions and improve robustness for various Linux versions. The experimental results showed that the proposed method precisely estimates the hook point for various OS versions and OSes. In addition, the overhead of the proposed method is small, considering the boot time of the monitored VM.

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ネットワーク上の攻撃者は攻撃対象を見つけるためにスキャン攻撃を行う傾向がある．スキャン攻撃とは，攻撃者が攻撃対象のサーバやサービスについての情報を収集する行為である．我々は，scan攻撃を検知するシステムを運用している．本論文では，検知した攻撃者への応答をZebraサーバのblack holeインターフェースへ向けることにより応答パケットを遮断し，情報を与えないようにする手法について述べる．この方法ではネットワークルーティングの特性を利用するため，LANスイッチ等への負担を軽減できる．

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This paper proposes a novel transport-layer protocol called Sender Initiated Congestion Control (SICC) which provides congestion control for Small Group Multicast (SGM). SGM is an effective solution for carrying a large number of simultaneous small-sized group communications. We provide simulated and experimental results to show that SICC is capable of achieving fast congestion avoidance and significantly increases throughput at receivers while still remaining TCP friendly. In SICC, multiple transmission rates are pre-defined as constant values for a given session, and each rate is associated with a different SICC CLASS. Each CLASS corresponds to an SGM group containing receivers with similar acceptable sending rates. The acceptable sending rate of each receiver is estimated at the sender using TCP-Friendly Rate Control (TFRC) in response to the loss event rate reported by the receiver. Based on receiver's reports, the rate that a sender uses to transmit packets to a receiver can be dynamically changed by assigning the receiver to one of the other SICC CLASS. These are the first reported results for congestion control in SGM.

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Power consumption has become an important factor in the design of high-performance computer systems. The power consumption of newer systems is now published but is unknown for many older systems. Data for only two or three generations of systems are insufficient for projecting the performance/power of future systems. We measured the performance and power consumption of 70 computer systems from 1989 to 2011. Our collection of computers included desktop and laptop personal computers, workstations, handheld devices and supercomputers. This is the first paper reporting the performance and power consumption of systems over twenty years, using a uniform method. The primary benchmark we used was Dhrystone. We also used NAS Parallel Benchmarks and CPU2006 suite. The Dhrystone/power ratio was found to be growing exponentially. The data we obtained indicates that the Dhrystone result and the CINT2006 in SPEC CPU2006 correlate closely. The NAS Parallel Benchmarks and CFP2006 results also correlate. Using the trend of Dhrystone/power that we obtained, we predict that the Dhrystone/power ratio will reach 2, 963 VAX MIPS/Watt in 2018, when exaflops machines are expected to appear.

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The rapid growth of information and communication technology (ICT) gives a lot of alternatives in supporting human work. ICT plays an important role in teaching and learning process. A learning system that uses ICT is called E-Learning. Statistics is still considered as a spooky subject by most of students, especially the first year students. On the other hand, it is a mandatory subject. To solve this problem, a web based statistical learning system, namely RWikiStat 2.0, has been created. It is an open source system for statistical learning supported by the technology of Wiki, and R statistical software as its statistical engine. This system is the improvement of the previous one.

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An x-ray powder diffraction technique with an imaging plate area detector is now widely used in various experimental fields including high pressure research. We developed a computer program named PIP capable of converting two-dimensional powder image to one-dimensional pattern. An aim of this program is to prepare easily, quickly, and user friendly one-dimensional diffraction patterns available for structure analysis such as Rietveld method. In this report, we answer some questions about PIP frequently asked by users.

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From 1992 to 1994, BSD which was UNIX developed at the University of California, Berkeley (UC Berkeley), found itself involved in a license-related lawsuit filed by AT&T. At around the same time, the GNU project, which developed a UNIX-like free software not infringing on the AT&T license, was nearing completion—the “jigsaw puzzle"—with the exception of the kernel. Linux, a free UNIX-style software kernel with open source code free from the AT&T license made its appearance as the desired kernel becoming the “last piece" of the puzzle. A UNIX-type operating system is an aggregate of single function programs called tools, which are easily substitutable. Under these conditions, the free software system, noted for being “UNIX running on a PC," was completed in a short span of time. Essential to the success of Linux was its miraculous release timing. It goes without saying that this phenomenon is unlikely to be repeated even under ideal conditions of it being free of charge and open source.

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A large-scale image sensing extended over very wide area can be realized by numerous image sensors, however, tremendous volume of data can cause adverse effects to the system such as network congestion. As a result, the system performance will be greatly deteriorated. One of the feasible ways to cope with such problem is to use smart image sensors as image acquisition devices because they can reduce the data volume on sensor level. In this paper, as a practical solution, we propose dynamic data rate control by adjusting spatial or temporal resolution with sampling-variant smart image sensors. Simulation results show that this scheme can provide an efficient use of network resources while preserving main objects in the scenes.

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自動駐車制御には様々な方法が研究されているが、それらには安全性の問題が残っており、完全自動には到っていない。本研究ではテストロボットの試作を行い、障害物(他車)や人の飛び出しなどを検知する安全自動駐車システムの開発を行った。
本研究では試作した走行ロボットに距離センサーや人体検出センサーを搭載し、それを利用して自動車庫入れと障害物検知による安全走行を実現するため、駐車目標の探索、走行経路の計算、障害物検知方法を検討した。そして、自動的に駐車場所を探索し、人の飛び出しなどを検知する機能を持った安全かつ安全自動駐車制御をMatlab上にシミュレーションし、走行ロボットで検証している。

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In this paper, we propose a virtualization architecture for a multi-core embedded system to provide more system reliability and security while maintaining performance and without introducing additional special hardware supports or implementing a complex protection mechanism in the virtualization layer. Embedded systems, especially consumer electronics, have often used virtualization. Virtualization is not a new technique, as there are various uses for both GPOS (General Purpose Operating System) and RTOS (Real Time Operating System). The surge of the multi-core platforms in embedded systems also helps consolidate the virtualization system for better performance and lower power consumption. Embedded virtualization design usually uses two approaches. The first is to use the traditional VMM, but it is too complicated for use in the embedded environment without additional special hardware support. The other approach uses the microkernel, which imposes a modular design. The guest systems, however, would suffer from considerable modifications in this approach, as the microkernel allows guest systems to run in the user space. For some RTOSes and their applications originally running in the kernel space, this second approach is more difficult to use because those codes use many privileged instructions. To achieve better reliability and keep the virtualization layer design lightweight, this work uses a common hardware component adopted in multi-core embedded processors. In most embedded platforms, vendors provide additional on-chip local memory for each physical core, and these local memory areas are only private to their cores. By taking advantage of this memory architecture, we can mitigate the above-mentioned problems at once. We choose to re-map the virtualization layer's program on the local memory, called SPUMONE, which runs all guest systems in the kernel space. Doing so, it can provide additional reliability and security for the entire system because the SPUMONE design in a multi-core platform has each instance installed on a separate processor core. This design differs from traditional virtualization layer design, and the content of each SPUMONE is inaccessible to the others. We also achieve this goal without adding overhead to the overall performance.

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This article introduces a conversion method from paper-based seismic profiles to SEG-Y formatted degital data. This method employs two free software, NetPBM and Seismic Unix which work on Unix-like OS. The principle is 1) scanning paper-based profiles to obtain pixel images conposed of 8 bit charactor, 2) conversion of trace data format from character to floating and 3) paste of SEG-Y header to floating trace data. Paper-based profiles drown by line scan recorder were successfully converted to trace-by-pixel SEG-Y data. Paper based wiggle profiles were converted firstly to trace-by-pixel SEG-Y data, and then to trace-by-trace SEG-Y data, by using horizontal trace sum of trace-by-pixel data. Quality of these data was examined and proofed that they are tolerable to be used, though they have restriction of paper. SEG-Y convertied data would provide additional analyses; deconvolution, migration, seismic attribute analyses, and would be ready for interpretation softwares.

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我々は，3つのモードを切り替えることで高い作業移動能力を発揮する6脚ロボットを開発した．本論文では，動力学シミュレータODEを用い，段差登り能力を解析する．はじめに，通常の平地移動に用いている6脚トライポッド歩容による段差登りをシミュレーションし，踏破可能な段差の高さを解析する．次に，より高い段差を登るための歩容を提案し，胴体を水平にした状態で登ることのできる段差の最大高さを求める．

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