Faculty Profiles - MURASE Tutomu

Papers - MURASE Tutomu

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VM Migration Control that Assures and Maximizes Quality in Multi-stage Information Processing Systems

Kazutoshi Nakane,Yukinobu Fukushima,Celimuge Wu,Yusheng Ji,Tutomu Murase

IEICE Technical Report Vol. IN2023-25 page： 46 - 51 2023.7

Longcut route of multiple autonomous mobile robots forming ad hoc networks to avoid interference from other networks Reviewed

R. Takeuchi and T. Murase

2023 International Conference on Consumer Electronics - Taiwan (ICCE-Taiwan) page： 485 - 486 2023.7

Longcut route of multiple autonomous mobile robots forming ad hoc networks to avoid interference from other networks Reviewed

R. Takeuchi and T. Murase

2023 International Conference on Consumer Electronics - Taiwan (ICCE-Taiwan) page： 485 - 486 2023.7

Mobility Control of Avoiding Interference for Autonomous Mobile Robot Ad Hoc Networks Reviewed

Kota Makino, Takeshi Hirai, Tutomu Murase

2023 IEEE International Conference on Consumer Electronics (ICCE) Vol. 2023-January 2023.1

AP Cooperative Mobility Control for Public Mesh Network Reviewed

Shibuya Y., Hasegawa Y., Obata H., Murase T.

Digest of Technical Papers - IEEE International Conference on Consumer Electronics Vol. 2023-January 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Digest of Technical Papers - IEEE International Conference on Consumer Electronics

In a public mesh network, we propose a control method to move mesh access points (APs) to optimal locations in response to traffic condition changes and evaluate the effectiveness of the move. To adapt the dynamic movement of pedestrian terminals accommodated in the mesh network, we configure a mesh network with in-UAV APs and move the APs with the UAVs. In the calculation to find the optimal location that minimizes the AP's moving distance and maximizes the user traffic accommodation, it is not realistic to find the exact solution in brute force ways. Thus, we propose a heuristic method (DMT method) that iteratively applies a minimum spanning tree method to determine the connectivity of all terminals and a spring balance model to determine the optimal AP locations. The proposed method was proven effective with the evaluation results in which throughput was improved up to 5.21 times compared to that before the move, and was approximately 95% of the exact solution.

DOI： 10.1109/ICCE56470.2023.10043506

Scopus

CiNii Research

AP Cooperative Mobility Control for Public Mesh Network Reviewed

Shibuya, Y; Hasegawa, Y; Obata, H; Murase, T

2023 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS, ICCE 2023

Mobility Control of Avoiding Interference for Autonomous Mobile Robot Ad Hoc Networks Reviewed

Makino, K; Hirai, T; Murase, T

2023 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS, ICCE 2023

Longcut route of multiple autonomous mobile robots forming ad hoc networks to avoid interference from other networks Reviewed

Takeuchi R., Murase T.

2023 International Conference on Consumer Electronics - Taiwan, ICCE-Taiwan 2023 - Proceedings page： 485 - 486 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：2023 International Conference on Consumer Electronics - Taiwan, ICCE-Taiwan 2023 - Proceedings

We propose a novel travel route control for autonomous mobile robots (AMRs) ad hoc networks. In this method, relaying AMRs (referred to as "nodes") can provide high throughput for a longer time by relaying other nodes data and taking a route that mitigates interference from external networks. Relay nodes form the ad hoc network as they move. At this time, it takes a longcut route on its own path for the best performance, so that it can take the best position for relaying. In ad hoc networks formed with moving nodes, it is difficult to comprehensively consider effects of influence from external network and effects of communication distance with adjacent communication node. Thus, it is also difficult to set up an optimal route in which relay nodes can take a longcut route and take the best position for relaying. The evaluation results showed that the proposed method can maintain high throughput in 72% of the routes.

DOI： 10.1109/ICCE-Taiwan58799.2023.10226919

Scopus

Longcut route control of a relay-node under the effect of strong interference in an ad hoc network with multiple autonomous robots Reviewed

Takeuchi R., Murase T.

2023 IEEE 14th Annual Ubiquitous Computing, Electronics and Mobile Communication Conference, UEMCON 2023 page： 619 - 625 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：2023 IEEE 14th Annual Ubiquitous Computing, Electronics and Mobile Communication Conference, UEMCON 2023

We have studied and confirmed the effectiveness of a previously proposed relay-node routing method for ad hoc networks with autonomous mobile robots (AMRs) when the effects of interference on throughput are significant. The system under study is a wireless LAN ad hoc network in which AMRs communicate with edge servers with the support of relaying AMRs. The problem with ad hoc networks composed of AMRs is that it is difficult to set up optimal routes that can be made by relay-nodes making longcut routes. This is because it is difficult to comprehensively consider the degree of influence due to interference from external networks and the degree of influence due to communication distance with neighboring communication nodes. Therefore, in the VDR method, we model the factors involved in route setting from time to time as vectors, synthesize them, and control the movement in the direction indicated by the synthesized vectors. We have qualitatively and quantitatively evaluated the VDR method and found that the results are almost the same or better than those of conventional methods, even when the effects of interference are large.

DOI： 10.1109/UEMCON59035.2023.10316178

Scopus

Improvement of Throughput by User Cooperative Mobility with Restricted Position in Ad-Hoc Networks Reviewed

Inaoka K., Xie J., Takanashi M., Makido S., Murase T.

IEEE International Conference on Consumer Electronics - Berlin, ICCE-Berlin page： 1 - 5 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE International Conference on Consumer Electronics - Berlin, ICCE-Berlin

In this paper, we evaluate the effectiveness of user cooperative mobility in ad-hoc networks with restriction that arise when the nodes are vehicles parked on side of the road. Conventional methods have been proposed to move nodes to proper positions in order to achieve the maximum throughput of the whole networks. However, in the case of ad-hoc networks utilizing parked vehicles, nodes are only allowed to move alongside roads. It is concerned that conventional user cooperative mobility methods would be useless, but no studies have mentioned this problem. In this study, we assume a service that vehicles parked on side of the road form an ad-hoc networks and provide wireless LANs service to neighboring pedestrians. We compare the throughput performances with and without the restriction. In a simple model where nodes are placed in uniform, we showed that the throughput with the restriction was improved by 50%. Furthermore, with ten thousand trials in a model where nodes are placed at random, we also showed that the throughput was improved by 52.8% on average. This result indicates that user cooperative mobility is effective even with restricted position.

DOI： 10.1109/ICCE-Berlin58801.2023.10375668

Scopus

User Selection of Mobility Control for Throughput Improvement in Ad Hoc Networks Reviewed

Anjiki T., Murase T.

Digest of Technical Papers - IEEE International Conference on Consumer Electronics Vol. 2022-January 2022

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Digest of Technical Papers - IEEE International Conference on Consumer Electronics

We propose an optimal user selection method on mobility control for ad hoc networks to improve QoS. In the proposed method, the best user, which is the best movable user for QoS, is selected based on physical distances between users in an ad hoc network and on the connection relationships between the users. The method also indicates the best destination to move that user to within a reasonable time. To reduce the search cost to obtain the best destination, the proposed method reduces the areas to be searched by identifying the discrete positions where transmission rates change according to the measurement data model. All the identified positions are examined to determine whether to relay another user to determine the best position. The evaluation results show that the proposed method achieved 99.0% of the maximum throughput obtained by moving the best user to the best destination. Throughput improvement of 10.3% was achieved compared with the conventional user mobility control method, which adopts a heuristic approach. Although the proposed method requires more running time than the conventional heuristic approach, it remains within a reasonable time.

DOI： 10.1109/ICCE53296.2022.9730310

Scopus

VM Migration Considering Downtime for Accuracy Improvement in Multi-stage Information Processing System. Reviewed

Kazutoshi Nakane, Takumi Anjiki, Jiquan Xie, Yukinobu Fukushima, Tutomu Murase

ICCE-TW page： 335 - 336 2022

User Cooperative Mobility to Improve TCP-BBR Throughput in Ad-Hoc Networks Reviewed

Ito N., Xie J., Obata H., Murase T.

Proceedings - 2022 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-Taiwan 2022 page： 333 - 334 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：Proceedings - 2022 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-Taiwan 2022

In this paper, we propose a user cooperative mobility to improve Transmission Control Protocol-Bottleneck Bandwidth and Round-trip propagation time (TCP-BBR) throughput. In a single-flow ad-hoc network with TCP-BBR traffic, the TCP-BBR does not work well due to the variation of Round-Trip Time (RTT). By considering the fact that TCP-BBR does not work well, the proposed Data suppression Acknowledge character (ACK) retention method stabilizes the RTT and improves the Wireless Local Area Network (WLAN) bandwidth at the same time. After giving an overview of the proposed method, we show the results of evaluating the throughput characteristics by NS3 simulation. The results show that the proposed method successfully improves the throughput by up to 232% compared to the throughput before moving, which is better than the conventional method, demonstrating the effectiveness of the proposed method.

DOI： 10.1109/ICCE-Taiwan55306.2022.9868988

Scopus

CiNii Research

Preface Reviewed

Murase T., Ishibashi Y.

WSCE 2022 - 2022 5th World Symposium on Communication Engineering 2022

Performance Improvement by Controlling VM Migration between Edge Nodes in a Multi-Stage Information Processing System Reviewed

Anjiki T., Nakane K., Murase T.

WSCE 2022 - 2022 5th World Symposium on Communication Engineering page： 53 - 58 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：WSCE 2022 - 2022 5th World Symposium on Communication Engineering

We propose two VM migration methods that improve the total sum of program correct by dynamically moving VMs to appropriate edge node. We assume a multi-hierarchy information processing system that the cloud data center and the edge node VM (Virtual Machine) perform processing at the same time, the data center completes all processing, and the VM has the required response time and returns a result that the processing has progressed (called accuracy). The first method is 'VM sweeping method' that allocates more CPU time to VMs that perform high accuracy processing. The second methods is 'VM sweeping method' that allocates more CPU time to VMs that perform high accuracy processing that improves per unit CPU time (AIR), and 'VM number averaging method' that attempts to move VMs so that the assignment status of the CPU time in all edge nodes is equal. The accuracy improvement effect of the proposed VM migration method was evaluated by a simulator. Evaluations changed the AIR from the Early-blooming type where the accuracy greatly increases in the first half to the Late-blooming type where the accuracy greatly increases in the second half, and comparing it with the case where the VM is not moved. It was clarified that a big effect can be expected in the VM sweeping method, and the VM number averaging method in the Earlyblooming type program.

DOI： 10.1109/WSCE56210.2022.9916044

Scopus

NOMA-dependent Low-Powered Retransmission in Sensing-based SPS for Cellular-V2X Mode 4 Reviewed

Hirai, T; Wakamiya, N; Murase, T

2022 IEEE 96TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2022-FALL) Vol. 2022-September 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE Vehicular Technology Conference

This paper proposes a retransmission strategy using the non-orthogonal multiple access (NOMA) in the PC5-based cellular-V2X mode 4 (called mode 4) to mitigate the channel congestion. The proposed strategy has two key ideas. The first idea is to allow each node (e.g., a car or a pedestrian) to retransmit its packet at lower transmission power than its original packet in the first transmission. The second idea is that each node aims to synchronize its low-powered retransmission with the first transmission of its neighbor node. The two key ideas boost the PRR through diversity effects by mitigating interference and providing power differences with widely deployed receivers. Our simulations highlighted that the proposed strategy outperformed the existing NOMA with retransmissions in mode 4 by 29%.

DOI： 10.1109/VTC2022-Fall57202.2022.10012826

Web of Science

Scopus

Coexistence Analysis of D2D-Unlicensed and Wi-Fi Communications Reviewed

Wang Ganggui, Wu Celimuge, Yoshinaga Tsutomu, Yin Rui, Murase Tutomu, Yau Kok-Lim Alvin, Bao Wugedele, Ji Yusheng

WIRELESS COMMUNICATIONS & MOBILE COMPUTING Vol. 2021 page： 1 - 11 2021.3

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Wireless Communications and Mobile Computing

By enabling direct communications between nearby user equipment (UE), device-to-device (D2D) communication has become one of the key technologies in 5th generation (5G) mobile networks. D2D communication brings new communication opportunities for mobile devices, especially in a highly dense network. In this paper, D2D communication in the unlicensed spectrum, namely, D2DUnlicensed (D2D-U), is discussed. The use of unlicensed frequency bands can ease the shortage of spectrum resources and improve network performance. However, the D2D-U in 5G has significant effects on the network performance of existing unlicensed networks sharing the same frequency bands, such as Wi-Fi and Bluetooth. Therefore, it is necessary to design a fair coexistence scheme for D2D-U. To understand the coexistence problem, in this paper, we first formulate the network performance of D2DU and Wi-Fi under two different coexistence schemes, namely, listen before talk (LBT) and duty cycle mechanism (DCM). Then, we use computer simulations to investigate a mode selection scheme that switches between these two schemes and point out the best possible solution for the coexistence between D2D-U and Wi-Fi.

DOI： 10.1155/2021/5523273

Web of Science

Scopus

Cooperative Mobility Control with Longcut Route Selection to Form Ad Hoc Networks for Multiple Autonomous Mobile Robots Reviewed

Makino K., Murase T.

2021 IEEE 10th Global Conference on Consumer Electronics, GCCE 2021 page： 930 - 931 2021

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2021 IEEE 10th Global Conference on Consumer Electronics, GCCE 2021

We propose a method to improve Quality of Service (QoS) between the IEEE802.11 AP (access point) and the AMR by using a neighboring AMR as a relay communication node. We assume a self-driving small vehicle as an AMR (Autonomous Mobile Robot) such as auto-driving wheelchair, which drives to an on-demand destination. The proposed method consists of a midpoint-following route control method and a relay control method. In the midpoint-following route control method, neighboring AMRs (Contribution-AMRs, C-AMRs) move in the direction of the midpoint between its AP and a moving AMR (Benefit-AMR, B-AMR). Then, the C-AMR could relay the B-AMR to the AP for better QoS. The relay control method decides whether to use the relay or not depending on estimations of throughput based on positions of B-AMRs, C-AMRs and APs. The proposed route control obtains semi-optimal move for a C-AMR and also obtains the highest throughput for a B-AMR. Because an initial position of the C-AMR significantly effects on QoS, QoS characteristics is discussed with the initial position.

DOI： 10.1109/GCCE53005.2021.9621922

Scopus

NOMA-Aided Probabilistic Cooperative Transmission for PC5-Based Cellular V2X Mode 4 for Crash Warning Reviewed

Takeshi Hirai, Tutomu Murase

IEEE ACCESS Vol. 9 page： 62602 - 62615 2021

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

This paper proposes a probabilistic cooperative transmission scheme with non-orthogonal multiple access (NOMA), named NO-ProbReM, for the PC5-based cellular-vehicle-to-everything (C-V2X) mode 4 in the crash warning system (CWS). In the proposed method, each node probabilistically selects a packet based on its cooperation ability under a limited cooperation power level, which is assigned within the total transmission power limit; then, the node superposes its own packet signal and the selected packet signal on a NOMA basis. The proposed probabilistic mechanism autonomously improves the link reliability within a specific range by the limited-assigned cooperation power while guaranteeing that the direct link is sufficiently similar reliability to mode 4. Our simulation results demonstrated that with suitable parameters, the proposed method mitigated the potential channel congestion of the current mode 4; in particular, the proposed method provided 50% better performance than the current mode 4 in the fundamental node density model. These results highlight that the proposed method advanced the infrastructure-less C-V2X in the CWS.

DOI： 10.1109/ACCESS.2021.3073731

Web of Science

Scopus

Maximum throughput strategy based on multiuser cooperative mobility under different location distributions in MANETs Reviewed

Xie J., Murase T.

2021 IEEE 10th Global Conference on Consumer Electronics, GCCE 2021 page： 643 - 644 2021

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2021 IEEE 10th Global Conference on Consumer Electronics, GCCE 2021

With the widespread adoption of the Internet of Things (IoT), throughput performance is a crucial metric in mobile ad hoc networks (MANETs) constrained by wireless bandwidth resources. Specifically, how to maximize throughput while keeping bandwidth resources constant needs to be explored. This paper investigates the optimal mobility strategy to maximize throughput in MANETs. Unlike previous studies, which mostly set a small number of fixed users and did not consider the location profiles, we jointly consider different location distributions and multiuser cooperative mobility to maximize the system throughput. On the one hand, we consider two scenarios of users' location distributions as centralized and decentralized, respectively. On the other hand, a game-theoretic approach can obtain the optimal strategy to maximize the system throughput for movable users. Numerical simulations show that the optimal cooperative mobility strategy yields 19.45% and 21.36% throughput gains over the previous intuitive approach for both location distributions.

DOI： 10.1109/GCCE53005.2021.9621974

Scopus

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Papers - MURASE Tutomu