http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Candidate Path Selection Method for TCP Performance Improvement in Fixed Robust Routing
Yukinobu Fukushima,Takashi Matsumura,Kazutaka Urushibara,Tokumi Yokohira 대한전자공학회 2016 IEIE Transactions on Smart Processing & Computing Vol.5 No.6
Fixed robust routing is attracting attention as routing that achieves high robustness against changes in traffic patterns without conducting traffic measurement and performing dynamic route changes. Fixed robust routing minimizes the worst-case maximum link load by distributing traffic of every source-destination (s-d) router pair onto multiple candidate paths (multipath routing). Multipath routing, however, can result in performance degradation of Transmission Control Protocol (TCP) because of frequent out-of-order packet arrivals. In this paper, we first investigate the influence of multipath routing on TCP performance under fixed robust routing with a simulation using ns-2. The simulation results clarify that TCP throughput greatly degrades with multipath routing. We next propose a candidate path selection method to improve TCP throughput while suppressing the worst-case maximum link load to less than the allowed level under fixed robust routing. The method selects a single candidate path for each of a predetermined ratio of s-d router pairs in order to avoid TCP performance degradation, and it selects multiple candidate paths for each of the other router pairs in order to suppress the worst-case maximum link load. Numerical examples show that, provided the worst-case maximum link load is less than 1.0, our proposed method achieves about six times the TCP throughput as the original fixed robust routing.
Dynamic splitting of light trails for increasing throughput in light trail networks
Yukinobu Fukushima,Kota Tanaka,Wenjie Chen,Tokumi Yokohira 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
As a promising medium access control method in light trail networks, ART MAC based on token passing has been proposed. In order to increase throughput of ART MAC, we propose a dynamic light trail splitting method. Our method increases throughput of a light trail by splitting a light trail into two trails at the token holding node and enabling simultaneous data transmission on both trails. Simulation results show that our method achieves 23-32 % higher throughput than a light trail without splitting.
A Prototype Virtual Network Embedding System using OpenStack
Yukinobu Fukushima,Kohei Sato,Itsuho Goda,Heung-Gyoon Ryu,Tokumi Yokohira 대한전자공학회 2017 IEIE Transactions on Smart Processing & Computing Vol.6 No.1
Network virtualization enables us to make efficient use of resources in a physical network by embedding multiple virtual networks in the physical network. In this paper, we develop a prototype of a virtual network embedding system. Our system consists of OpenStack, which is an open source cloud service platform, and shell scripts. Because OpenStack does not provide a quality of service control function, we realize bandwidth reservation for virtual links by making use of the ingress policing function of Open vSwitch, which is a virtual switch used in OpenStack. The shell scripts in our system automatically construct the required virtual network on the physical network using the OpenStack command-line interface, and they reserve bandwidth for virtual links using the Open vSwitch command. Experimental evaluation confirms that our system constructs the requested virtual network and appropriately allocates node and link resources to it.
Modification of Enigmail to Use Unique Cryptographic Algorithms in Email
Ryotaro Tani,Yukinobu Fukushima,Yuya Tarutani 대한전자공학회 2021 IEIE Transactions on Smart Processing & Computing Vol.10 No.5
In this paper, we modify an email client so that it can use unique cryptographic algorithms instead of general cryptographic algorithms for improved security. We use Thunderbird as an email client and modify Enigmail, which is an extension for Thunderbird, to use cryptographic algorithms implemented in GNU Privacy Guard (GnuPG). To achieve this goal, we first dynamically analyze the source code of Enigmail and identify the parts related to processing with GnuPG. Then, we modify the identified parts so that Enigmail can use unique cryptographic algorithms, which are assumed to be implemented in GnuPG. The experimental evaluation confirms that the modified Enigmail securely exchanges email messages using pseudo-unique cryptographic algorithms, and confirms that the processing overhead of the modified Enigmail is negligibly small.
Consensus Building using Deep Reinforcement Learning for Energy Management
Yuya Tarutani,Isato Oishi,Yukinobu Fukushima,Tokumi Yokohira 대한전자공학회 2022 IEIE Transactions on Smart Processing & Computing Vol.11 No.4
A variety of information is collected from IoT devices. As those devices become more familiar to users, network services must consider the influence of the user. We propose a method to maximize the value from power consumption and minimize the cost incurred to ensure user satisfaction. However, one problem is that user satisfaction cannot increase because it is considered a constraint on power consumption. In this paper, we propose a consensus building method to minimize power consumption and maximize user satisfaction. An exhaustive search incurs a large calculation overhead to determine device parameters. Thus, the proposed method uses reinforcement learning to solve this problem. From its evaluation, we clarify that the proposed method attains about 1.5 times the total reward compared with the conventional method. Moreover, we also clarify that 99.9% of the total reward can be achieved, compared to the exhaustive search.
Development of Optical Device Housing Compacted Using SUS304L Granulated Powders
Suzuki Hironori,Hara Toshihiro,Ogino Yukinobu,Sato Yasushi,Tomota Yo 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
In order to develop the SUS304L housing by powder metallurgy for an optical device useful for the FTTH communication system, the optimum compacting pressure and sintering temperature were investigated using granulated powder as the material to satisfy high air-tightness and high laser-weldability. Then the laser-welding test of specimen made under the optimum condition was carried out to observe welding sputters.