| VO QUOC TRINH | D, 中間発表 | ネットワークシステム学 | 岡田 実, 林 優一, 東野 武史, Dong Quang Thang |
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title: Constant Output Voltage Design in Inductive Power Transfer Systems with Relay Coils
abstract: Inductive power transfer (IPT) is a wireless energy transmission technique based on the mutual coupling among two or more coils. In a typical IPT system, the load voltage basically fluctuates with every change in the load impedance, resulting in unstable working conditions for the load itself. For that reason, many constant voltage designs have been proposed in the open literatures. However, most of them can only be applied to one-receiver topologies. Similar design for complicated systems with multiple receivers is still an open issue. In this research, I address this challenge by focusing on the simple method of using relay coils, which has been shown to be very effective for one-receiver systems. In this presentation, I will report my success in stabilizing and adjusting the load voltages to reach different rated values. This result is significant because in multiple-receiver system, each receiver may require different rated voltage for its operations. This presentation will also briefly discuss the next steps to finalize my research. language of the presentation: English | |||
| 磯貝 昇吾 | M, 2回目発表 | ネットワークシステム学 | 岡田 実, 林 優一, 東野 武史, Dong Quang Thang |
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title: Study on Secondary-Side Compensation Circuit for Inductive Power Transfer System
abstract: propose a novel compensation circuit for inductive power transfer system which is implemented only at the secondary side. This method can simplify primary side while realizing load-independent constant voltage/current functionality. Moreover, this system can feed only authorized receivers by using the inductance of the transmitting coil and the mutual inductance as the pass code necessary for power supply, because the design of this topology requires the inductances of IPT coils and their mutual inductance. In my presentation, I provide simulation and experiment results to verify effectiveness of this topology. language of the presentation: Japanese | |||
| 大橋 達矢 | M, 2回目発表 | ネットワークシステム学 | 岡田 実, 林 優一, 東野 武史, Dong Quang Thang |
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title: Dynamic Charging Using Off-Resonant Coil Array With Receiver-side Compensation
abstract: This presentation proposes a dynamic charging system for moving receiver by using an array of small off-resonant coils in a combination with receiver-side compensation circuit. Compared to the size of receiving coil, transmitting coils are small enough to make the coupling coefficient stable when the receiver moves along the transmit coil array. The compensation circuit at the receiver will be designed to approximately cancel out all the reactive components in the coupling link between the receiving coil and the nearby transmitting coils. As a result, the load will be seen almost directly from the source, and thus, stable output voltage can be achieved even if the receiver moves and/or if the load resistance varies. Experimental results confirm effectiveness of the proposed system. language of the presentation: Japanese | |||
| 川合 崇大 | M, 2回目発表 | ネットワークシステム学 | 岡田 実, 林 優一, 東野 武史, Dong Quang Thang |
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title: Study on Constant Voltage Design for Single-Frequency Two-Stream Contactless Power Transfer With Cross-Coupling
abstract:s paper proposes a voltage stabilization scheme for feeding constant voltage to receiver in single-frequency two-stream contactless power transmission under the presence of cross coupling among couplers. We have demonstrated that the constant voltage could be provided to receiver load with mitigating cross coupling by inserting a compensation block followed couplers at receiver. In order to obtain more stable voltage rather than previous scheme, dividing a compensation block into two parts is newly proposed. A part of block is placed in the vicinity of transmitter couplers. Computer simulation including electro-magnetic and electric circuit was conducted for comparing the performance. language of the presentation: Japanese | |||
| 佐野 友哉 | M, 2回目発表 | ユビキタスコンピューティングシステム | 安本 慶一, 藤川 和利, 荒川 豊, 諏訪 博彦 |
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title: Transportation Request Collection System for Elderly People in Demand Responsive Transportation Service
abstract: In recent years, due to aging and depopulation, the shortage of the transportation for elderly has become a problem. Therefore it is expected that demand-responsive traffic such as volunteer transportation and demand buses ensures the transportation. In demand-responsive traffic, pick-up requests are collected via telephone or application. However, the collection of requests by telephone places a heavy burden on the pick-up manager, and in the case of applications, it is difficult for elderly people who do not own a smartphone or are unfamiliar with operation to use it. Therefore, in this study, we propose a pickup request collection system that easily collects pickup requests from the elderly and makes them visible to the pickup manager for demand-responsive volunteer transportation. In the proposed system, the pick-up requests are sent from dedicated devices installed in the home of the elderly and visualized to the volunteer staff via LPWA communication. language of the presentation: Japanese 発表題目: デマンド応答型外出支援サービスにおける高齢者向け送迎要求収集システム 発表概要: 近年，高齢化や過疎化により高齢者の移動手段の不足が問題になっており，移送手段の確保のために，ボランティア輸送やデマンドバスなどデマンド応答型交通による移動支援に期待が高まっている．デマンド応答型交通では，送迎要求を電話やアプリケーションを介して受け取るが，電話での聞き取りには送迎管理の負担が大きく，アプリケーションでは，スマートフォンを所有していない，あるいは，操作に不慣れな高齢者にとっては利用が難しいという問題点がある．そこで本研究では，デマンド応答型のボランティア輸送を対象に，高齢者から容易に送迎要求を収集し，送迎管理者に可視化できる送迎要求収集システムを提案する．提案システムでは，高齢者向けに新たに開発した要求送信デバイスを高齢者宅に設置し，LPWAによる通信を介して地域の送迎要求を収集し，ボランティア輸送を管理するスタッフに可視化を行う． | |||
| 吉田 茉菜 | M, 2回目発表 | モバイルコンピューティング | 伊藤 実, 藤川 和利, 柴田 直樹, 川上 朋也 |
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title: Proposal of pricing method based on demand distribution in road pricing
abstract:Traffic congestion is a serious problem that causes significant social losses. Especially, expressways enable users to quickly reach their destinations by paying fees, but traffic congestion is one of the main factors to strongly disturb the advantage. Various techniques have been studied to reduce traffic congestion. One of them is real-time road pricing on expressways. I propose a pricing method based on demand distribution. In this study, the price is recalculated to reflect changes in the situation such as accidents, and the updated price is notified to the user. Therefore, I will investigate the price update method that can dynamically control traffic. language of the presentation : Japanese | |||
| 西 洋平 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, 藤川 和利, 笹部 昌弘 |
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title: Impact of Locality-awareness on Tit-for-Tat-based P2P File Distribution
abstract: Periodic software update is one of preventive measures against malicious attacks. In case of the software which is used by many users, e.g., Operating System (OS), the distribution server for update tends to be a bottleneck. To tackle this problem, several systems, e.g., Windows update, recently apply Peer-to-Peer (P2P) file distribution where clients called peers upload retrieved fragments of the whole content, i.e., pieces, to other peers. However, some peers are hesitate to upload pieces to others, which are called free riders, due to communication overhead. Tit-for-Tat (TFT) strategy in game theory can alleviate such free riding behavior by encouraging exchange of an equivalent number of pieces among each pair of peers. In recent years, the optimality of P2P file distribution under strict TFT constraint has been analyzed. In this presentation, focusing on the fact that the communication overhead inside a group, e.g., LAN or AS, tends to be much less than that between different groups, we consider the locality-aware TFT-based P2P file distribution where the TFT constraint is relaxed for intra-group communication. We model the relaxed TFT-based P2P file distribution as Integer Linear Programming (ILP), as in the existing work. Through numerical experiments, we first compare the system performance, i.e., average file download time, among the relaxed TFT model, strict TFT model, and ideal model with cooperative users. Furthermore, we reveal the performance of the relaxed TFT model from various aspects, e.g., system scale, the number of groups, and upload capacities of server and peers. language of the presentation: Japanese | |||
| 山本 将成 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, 藤川 和利, 笹部 昌弘 |
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title: Risk Evaluation of Block Diffusion Delaying Attacks in a Bitcoin Network
abstract: In the Bitcoin system,transactions and their collections, i.e., blocks, are distributed over a Peer-to-Peer (P2P) network (i.e., Bitcoin network) constructed by participating nodes. Each node maintains a distributed ledger called blockchain that consists of retrieved blocks. Therefore, speedy block distribution over the network is essential for all nodes to reach a global consensus on the blockchain. On the other hand, Bitcoin clients are developed as open source software, and thus can be modified by malicious users. In the existing work, it has been pointed out that an adversary can delay the block propagation between neighboring nodes by exploiting the regular timeout mechanism for block transfer. In this paper, we focus on a new risk of block diffusion delay attack where a specific miner, which is a special node that tries to build blocks, colluding with multiple adversaries disturbs the propagation of blocks generated by competing miners. Through simulation experiments, we reveal how the number of adversaries and their locations in the network affect the risk of block diffusion delay attack. language of the presentation: Japanese | |||