检索结果-南通市图书馆

A Low-Load QoS Routing Method for OpenFlow Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications and Network 2016年第3期8卷 144-157页

作者： Shinnosuke Kimura kenya sato Graduate School of Information and Computer Science Doshisha University Kyoto Japan

As the volume of Internet traffic continues to grow, there is a need for mechanisms that ensure communication quality that is suitable for different applications. OpenFlow implements per-flow routing control but can have adverse effects on communication quality when the number of flow entries is increased. In this study, we propose a routing method that controls traffic flows by labeling them with numbers representing the source switch, destination switch and required communication quality. The OpenFlow controller then sets up flow entries on a per-label basis rather than on a per-flow basis, allowing it to reduce the number of flow entries. In an evaluation test, we confirmed that the labeling method could prevent this reduction in communication quality.

关键词： Routing Method Traffic Control OpenFlow QoS Labeling

A Promising Distance-Based Gasoline Tax Charging System Based on Spatio-Temporal Grid Reservation in the Era of Zero-Emission Vehicles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2022年第4期12卷 651-680页

作者： Babakarkhail Habibullah Rui Teng kenya sato Network Information Systems Doshisha University Kyotanabe Japan Mobility Research Center Doshisha University Kyotanabe Japan

Fuel taxes are still a primary funding source for the development and maintenance of transportation infrastructure. Such a tax is collected as a flat fee from the importer or producer of the taxable fuel product. Fuel-efficiency improvements and the adoption of zero-emission vehicles result in a continuous decrease in gasoline tax revenues. This paper proposes a novel distance-based alternative method to replace current gasoline tax collection systems in Japan by providing a software architecture platform. In this platform, we utilize driving information gathered via communication mechanisms installed in connected automated vehicles to develop a system that collects gasoline tax based on reserving spatio-temporal grids. Spatio-temporal sections are created by dividing space and time into equal grids and a designated tax charge is assigned. Connected automated vehicles reserve a planned travel route in advance and travel based on reservation information. The performance evaluation results indicate that the proposed system adequately reserves the requested grids and accurately collects gasoline taxes based on a spatio-temporal grid with minimum communication time and no data package loss. The proposed method is based on micro travel distance charges, which generates gasoline tax revenue by 5.7 percent for model year 2022 and 21.8 percent for model year 2030 as compared to the current flat-fee system.

关键词： Automated Vehicle Zero-Emission Vehicle Gasoline Tax Micro-Road-Pricing Spatio-Temporal-Grid

Reachability-Based Packet Scheduler of Multipath QUIC for Heterogeneous Mobile Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications and Network 2022年第4期14卷 200-209页

作者： Riki Okunishi Rui Teng kenya sato Graduate School of Science and Engineering Doshisha University Kyoto Japan Mobility Research Center Doshisha University Kyoto Japan

In recent years, we need more bandwidth to enjoy entertainment contents such as video streaming, music and online gaming. To gain enough bandwidth, technologies that combine bandwidth by using multiple interfaces at same time are desired. Multipath transport protocols which combine multiple paths for packet delivery at the transport layer are a promising technology. Such protocols have a mechanism, called “packet scheduler”, to select the interface to send a packet. However, existing studies of the packet scheduler have not explicitly considered the compatibility of mobility with bonding of bandwidth. Therefore, when smartphone users move out of coverage of communication networks such as wireless Local Area Network (LAN) and Long Term Evolution (LTE) by vehicle, packet loss occurs, leading to a decrease of throughput. In this study, we propose a packet scheduler that selects an appropriate communication path so that packets can reach the peer before it moves out of the coverage. Based on routes of a vehicle and the position and communication range of the access point, the time at which a communication path will be lost is predicted. In addition, we employ MPQUIC (Multipath QUIC (Quick UDP Internet Connections)), which is a multipath transport protocol proposed as the extension of QUIC protocol, to reduce the ACK packet loss in multipath communication, and to reduce the time until the starts of retransmission. We evaluated the number of packet losses, the throughput and the time until starts of retransmission using a simulator and show the superiority of proposed method.

关键词： Mobility Multipath Transport Protocol Multipath QUIC

Highway Toll Collection Method for Connected Automated Vehicle Platooning Using Spatio-Temporal Grid Reservation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications and Network 2022年第4期14卷 171-199页

作者： Babakarkhail Habibullah Rui Teng kenya sato Network Information Systems Doshisha University Kyotanabe Japan Mobility Research Center Doshisha University Kyotanabe Japan

In the intelligent transportation system, the autonomous vehicle platoon is a promising concept for addressing traffic congestion problems. However, under certain conditions, the platoon’s advantage cannot be properly developed, especially when stopping for electronic toll collection (ETC) to pay the toll fee using the highway. This study proposes a software architectural platform that enables connected automated vehicles to reserve a grid-based alternative approach to replace current highway toll collection systems. A planned travel route is reserved in advance by a connected automated vehicle in a platoon, and travel is based on reservation information. We use driving information acquired by communication mechanisms installed in connected automated vehicles to develop a dynamic map platform that collects highway toll tax based on reserving spatio-temporal grids. Spatio-temporal sections are developed by dividing space and time into equal grids and assigning a certain road tax rate. The results of the performance evaluation reveal that the proposed method appropriately reserves the specified grids and collects toll taxes accurately based on a spatio-temporal grid with minimal communication time and no data package loss. Likely, using the proposed method to mediate driving on a one-kilometer route takes an average of 36.5 seconds, as compared to ETC and the combination of ETC and freeway road lane methods, which take 46.6 and 53.8 seconds, respectively, for 1000 vehicles. Consequently, our proposed method’s travel time improvements will reduce congestion by more effectively exploiting road capacity as well as enhance the number of platoons while providing non-stoppable travel for autonomous vehicles.

关键词： Autonomous Vehicle Platoon Highway Toll Tax Grid-Based Toll Charges Spatio-Temporal-Grid Dynamic Map

An Average Power Reduction Method for Web Applications on Wireless Terminals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications and Network 2012年第2期4卷 139-145页

作者： Toshiya Koyasu Hideki Shimada kenya sato Department of Information Systems Design Doshisha University Kyoto Japan

Recently, there is a widespread use of Web browser-based Web applications such as e-mails and chats. However, frequent communication between mobile wireless terminals and HTTP servers give rise to problematic increases of average power consumption for the mobile devices. Current attempts to tackle this problem focus on reducing power consumption at the network and data link layers used by the devices. In this study, we propose a different solution where certain functionalities of the mobile application are delegated to other devices with abundant power resources (either from large capacity batteries or power outlets). This method off-loads parts of the communication process normally done at wireless terminals to amply powered machines. With messages pushed from the machines only when the HTTP server responds with an update, the wireless terminal needs to transmit data less frequently, thus cutting down on power consumption. Our prototype implementing the proposed method succeeded in reducing the rise in average power consumption.

关键词： Web Applications Ajax Wireless Communication

Visualization and Management Platform with Augmented Reality for Wireless Sensor Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wireless Sensor Network 2015年第1期7卷 1-11页

作者： kenya sato Naoya Sakamoto Hideki Shimada Department of Information Systems Design Doshisha University Kyoto Japan

Recently a ubiquitous sensor network which collects our environmental information gets increasingly popular, a visualization application is necessary for users to manage complicated wireless networks, however, these applications are developed individually for wireless communication standard or a type of wireless device. Therefore, users are forced to adopt and use the application individually according to the target of the wireless network. In this paper, we propose a visualization platform for wireless network environments using augmented reality technology, and evaluate the effectiveness of the platform. From the result of the evaluation, we have confirmed the proposed platform has availability for visualization and management of wireless networks.

关键词： Network Management Visualization Augmented Reality

Design of Network Architecture Using Mobile Gateways for DLNA Devices in Wide Area Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications and Network 2012年第4期4卷 322-331页

作者： Hiroaki Goto Hideki Shimada kenya sato Department of Information Systems Design Doshisha University Kyoto Japan

The prevalence of information appliances supporting DLNA (Digital Living Network Alliance) such as televisions, recorders, and mobile phones has made it possible to share digital contents (e.g. videos, music and pictures) among appliances connected to a local network. However, DLNA does not let you share contents over different networks via the Internet. In this paper, we propose a network architecture where we adopt our SOAP method to mobile devices and use them as mobile gateways to consume digital contents from remote networks. We also confirm its practicality with a prototype.

关键词： Network Architecture DLNA Mobile Network Home Appliances

A Proposal of Sensor Data Collection System Using Mobile Relay Nodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wireless Sensor Network 2012年第1期4卷 1-7页

作者： Ryota Ayaki Hideki Shimada kenya sato 不详

In recent years, as embedded devices become smaller, cheaper and more diverse, the demand for urban sensing systems that present valuable information to users is increasing. However, in achieving urban sensing systems, the communication channel from the sensors to the data centers pose a problem, especially in respect to the cost of furnishing IP/mobile networks for each and every one of the sensor nodes. Many existing researches attempt to tackle this problem, but they generally limit either the types of sensors used or the distances among the sensors. In this paper, we propose a new sensor data collection system model in which mobile relay nodes transport the sensor data to the data center. We ran simulations under conditions imitating the real world to verify the practicality of the proposed system. This simulation uses data accumulated from traffic surveys to closely imitate pedestrians in the real world. We evaluated that the proposed system has sufficient ability to use in urban sensing systems that are not under the real-time constraint.

关键词： Wireless Sensor Networks Data Aggregation DTN Mobile Networks

Simulation Evaluation of Filtering Method for Improving Pedestrian Positioning Accuracy Using Signal Strengths

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wireless Sensor Network 2019年第6期11卷 81-94页

作者： Yuya Nishimaki Hisato Iwai kenya sato Computer and Information Science Graduate School of Science and Engineering Doshisha University Kyoto Japan Electrical and Electronic Engineering Graduate School of Science and Engineering Doshisha University Kyoto Japan

In recent years, we have been able to use various services using the position information of smartphones and tablets. In addition, research on intelligent transport systems (ITS) has been actively conducted. To consider reducing traffic accidents by exchanging position information between pedestrians and vehicles by vehicle-to-pedestrian communication, we require accurate position information for pedestrians and vehicles. The GPS (global positioning system) is the most widely used method for acquiring position information. However, in urban areas, the GPS signal is affected by the surrounding buildings, which increases the positioning error. In this study, a method to improve the positioning accuracy of pedestrians using the signal strengths from vehicles and beacons was proposed. First, a Kalman filter was applied to the signal strength. Then, the path loss index was dynamically calculated using vehicle-to-vehicle communication. Finally, the position of a pedestrian was obtained using weighted centroid localization (WCL) after filtering the nodes. The positioning accuracy was evaluated using a simulator and demonstrated the superiority of the proposed method.

关键词： Outdoor Positioning Vehicle-to-Pedestrian Communication Vehicle-to-Vehicle Communication Signal Strength Path Loss Index WCL