著者

Masahiko Morita Takehiro Tawara Masaomi Nishimura Shin Yoshizawa Bukai Chou Ippei Kuroki Takashi Ijiri Yuki Tsujimura Ryutaro Himeno Hideo Yokota

出版者

IJNC編集委員会

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.4, no.2, pp.369-391, 2014-07-14 (Released:2014-11-01)

参考文献数

68

被引用文献数

3

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Image analysis is crucial to medical and biological applications. Recent advances in imaging technology have led to the demand for processing and visualizing a large amount of three-dimensional (3D) biomedical images. In addition, cloud computing has become popular for managing big data. Unfortunately, conventional image-processing systems either lack cloud computing services or advanced 3D processing abilities. In this paper, we present a novel cloud-based system for sharing, processing, and visualizing 3D biomedical images. Our system employs a standard web browser as a client interface that interactively communicates with high-performance servers. Thus, an inexpensive tablet PC without an advanced graphics processing unit (GPU) can be used for 3D image processing and visualization. Our system provides the sharing of limited software and hardware resources, and it allows for effective collaboration between researchers. We demonstrate the applicability and functionality of the system by examining typical case studies on biomedical images. We also examine the performance of our system numerically.

著者

Masaya Sato Taku Omori Toshihiro Yamauchi Hideo Taniguchi

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.13, no.2, pp.273-286, 2023 (Released:2023-07-08)

参考文献数

17

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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.

著者

Shungo Kumazawa Kazushi Kawamura Thiem Van Chu Masato Motomura Jaehoon Yu

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.11, no.2, pp.215-230, 2021 (Released:2021-07-08)

参考文献数

14

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Training machine learning models on edge devices is always a conflict with power consumption and computing cost. This paper introduces a hardware-oriented training method called ExtraFerns for a unique subset of decision tree ensembles, which significantly decreases memory access and optimizes each tree in parallel. ExtraFerns benefits from the advantages of both extraTrees and randomFerns. As extraTrees does, it generates nodes by randomly selecting attributes and generating thresholds. Then, as randomFerns does, it builds ferns, which are decision trees that share identical nodes at each depth. In contrast to other ensemble methods using greedy optimization, ExtraFerns attempts global optimization of each fern. Experimental results show that ExtraFerns requires only 4.3% and 4.1% memory access for training models with 3.0% and 1.2% accuracy drops compared with randomForest and extraTrees, respectively. This paper also proposes applying lightweight random projection to ExtraFerns as a preprocessing step, which achieved a further accuracy improvement of up to 2.0% for image datasets.

著者

Alexander Yakubov Wazen Shbair Nida Khan Radu State Christophe Medinger Jean Hilger

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.10, no.1, pp.1-24, 2020 (Released:2020-01-23)

参考文献数

27

被引用文献数

5

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Pretty Good Privacy (PGP) is one of the most prominent cryptographic standards offering end-to-end encryption for email messages and other sensitive information exchange. PGP allows to verify the identity of the correspondent in information exchange as well as the information integrity. PGP implements asymmetric encryption with certificates shared through a network of PGP key servers. In this paper, we propose a new PGP management framework with the key servers infrastructure implemented using blockchain technology. Our approach offers fast propagation of certificate revocation among PGP key servers and elimination of man-in-the-middle risks. It also grants users the required access control to update their own PGP certificates, which is not the case with the current PGP key servers. A prototype has been implemented using Ethereum blockchain and an open source key server, named Hockeypuck. Finally, we evaluated the prototype with extensive experiments. Our results show that our solution is practical and it could be integrated with the existing public PGP key servers infrastructure.

著者

Jiahua Yu Qian-Ping Gu

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.6, no.2, pp.149-166, 2016 (Released:2017-03-23)

参考文献数

28

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Embedding graphs on the torus is a problem with both theoretical and practical importance. It is required to embed a graph on the torus for solving many application problems such as VLSI design, graph drawing and so on. Polynomial time and exponential time algorithms for embedding graphs on the torus are known. However, the polynomial time algorithms are very complex and their implementation has been a challenge for a long time. On the other hand, the implementations of some exponential time algorithms are known but they are not efficient for large graphs in practice. To develop an efficient practical tool for embedding graphs on the torus, we propose a new exponential time algorithm for embedding graphs on the torus. Compared with a well used previous exponential time algorithm, our algorithm has a better practical running time.

著者

Akihiro Suzuki Shuichi Oikawa

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.3, no.1, pp.153-169, 2013 (Released:2017-03-23)

参考文献数

28

被引用文献数

1 4

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Since embedded systems are used for various purposes at a variety of places, their security, reliability, and availability are important concerns. Virtualization technology has been used for a long time in order to improve the security of systems, and the other advanced features recently become available also to improve the reliability and/or availability. In order to apply virtualization technology to systems, the detailed analysis of target processor architectures is required. Although such analysis was performed for x86 architecture, it is not available for the ARM architecture, which is the most widely used processor architecture for embedded systems. This paper focuses on such analysis of the ARM processor architecture. We also present the implementation details of a virtual machine monitor (VMM) based on the analysis. We implemented a VMM, called SIVARM, for the ARM architecture to perform and verify the analysis of its ability to support a VMM. We successfully booted Linux on SIVARM and performed the evaluation by executing several benchmark programs on the ARM 1136JF-S processor. It verifies the analysis of the sensitive instructions and also enables the analysis of the performance impact of the virtualization.

著者

Takumi Honda Yasuaki Ito Koji Nakano

出版者

IJNC Editorial Committee

雑誌

International Journal of Networking and Computing (ISSN:21852839)

巻号頁・発行日

vol.7, no.1, pp.69-85, 2017 (Released:2017-02-07)

参考文献数

20

被引用文献数

1

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The main contribution of this paper is to present an implementation that performs the exhaustive search to verify the Collatz conjecture using a GPU. Consider the following operation on an arbitrary positive number: if the number is even, divide it by two, and if the number is odd, triple it and add one. The Collatz conjecture asserts that, starting from any positive number m, repeated iteration of the operations eventually produces the value 1. We have implemented it on NVIDIA GeForce GTX TITAN X and evaluated the performance. The experimental results show that, our GPU implementation can verify 1.31×1012 64-bit numbers per second. While the sequential CPU implementation on Intel Core i7-4790 can verify 5.25×109 64-bit numbers per second. Thus, our implementation on the GPU attains a speed-up factor of 249 over the sequential CPU implementation. Additionally, we accelerated the computation of counting the number of the above operations until a number reaches 1, called delay that is one of the mathematical interests for the Collatz conjecture by the GPU. Using a similar idea, we achieved a speed-up factor of 73.