Muroran-IT Academic Resource Archive
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Multiattribute-Based Double Auction Toward Resource Allocation in Vehicular Fog Computing
Get PDFapplication/pdfVehicular fog computing (VFC) could provide fast task processing services for vehicles. To make vehicles/fog nodes willing to buy/sell resources, a double auction mechanism considering the interests of all parties is needed. However, few works study the auction issue in VFC. Different from the existing edge-related auction which only considers the price, some nonprice attributes (location, reputation, and computing power) are also important for providing fair resource allocation in VFC. In this article, we propose a multiattribute-based double auction mechanism in VFC, which considers both the price and nonprice attributes for constructing reasonable matching. To the best of our knowledge, this is the first work to consider multiattribute-based auction in VFC. Our auction mechanism could satisfy computational efficiency, individual rationality, budget balance, and truthfulness. To verify the proposed mechanism, we simulate VFC using VISSIM and extract the driving data. The experimental results show the effectiveness and efficiency of this mechanism.journal articl
Development of downscaling method using the RBF network assessing the hourly population inflow: A case study of the Sapporo urban area
Get PDFapplication/pdfIn Japan in recent years, policies for compact cities have been promoted as the population has decreased, and the use of micro-geo data has attracted attention in urban planning. Therefore, when considering a compact city, it is important to know the relationship between the urban facility layout and the population flow. In this research, we created a data set using demographic data, location information of mobile phones, and detailed building data and used a radial basis function (RBF) network. In short, the purpose of this study was to develop a method to reduce the estimated area of population inflow per hour. Population inflow is expressed as the visiting population, which is defined by the difference in the staying population in the time of two sections. By spatially visualizing the results, we were able to downscale the population flow data on a 500 m grid.journal articl
Energy Cooperation in Battery-Free Wireless Communications with Radio Frequency Energy Harvesting
Get PDFapplication/pdfRadio frequency (RF) energy harvesting techniques are becoming a potential method to power battery-free wireless networks. In RF energy harvesting communications, energy cooperation enables shaping and optimization of the energy arrivals at the energy-receiving node to improve the overall system performance. In this paper, we proposed an energy cooperation scheme that enables energy cooperation in battery-free wireless networks with RF harvesting. We first study the battery-free wireless network with RF energy harvesting then state the problem that optimizing the system performance with limited harvesting energy through new energy cooperation protocol. Finally, from the extensive simulation results, our energy cooperation protocol performs better than the original battery-free wireless network solution.特集departmental bulletin pape
Field Survey Results of Building damage in Iburi and Hidaka Regions by 2018 Hokkaido Eastern Iburi Earthquake
Get PDFapplication/pdfOn September 6, 2018, Hokkaido Eastern Iburi Earthquake was occurred. The center of this earthquake is Atsuma of Iburi region. Moreover, the maximum seismic intensity was 7. After this earthquake, the authors investigated RC buildings and foundation damages in Iburi and Hidaka regions. As the result of the survey, however very sever damages were not confirmed, there were minor damages at RC nonstructural walls, RC expansion joints and foundations on banking. Therefore, a structural design methods are required for these members.特集departmental bulletin pape
Function-expansion-based topology optimization of three-dimensional optical waveguide devices with multi-layered structure considering layer thickness
Get PDFapplication/pdfSo far, as an optimal design method for 2D and 3D design of optical waveguide devices, topology optimization based on a function expansion method has been reported. In this paper, we improve the conventional functionexpansion-based topology optimization method to design three-dimensional photonic devices with structural variation in the depth direction. In order to design realistic 3D optical waveguide devices, we consider a layered structure and design each layer by using function-expansion-based topology optimization method. In this approach, undesired floating structures are avoided and layer thickness can be optimized. The validity of this method is verified through design examples of a polarization splitter and rotator (PSR) and a crossing waveguide which have two-layer structure.journal articl
A Study on Optimal Design of Optical Devices Utilizing Coupled Mode Theory and Machine Learning
Get PDFapplication/pdfWe propose a new design approach to improve the computational efficiency of an optimal design of optical waveguide devices utilizing coupled mode theory (CMT) and a neural network (NN). Recently, the NN has begun to be used for efficient optimal design of optical devices. In this paper, the eigenmode analysis required in the CMT is skipped by using the NN, and optimization with an evolutionary algorithm can be efficiently carried out. To verify usefulness of our approach, optimal design examples of a wavelength insensitive 3dB coupler, a 1 : 2 power splitter, and a wavelength demultiplexer are shown and their transmission properties obtained by the CMT with the NN (NN-CMT) are verified by comparing with those calculated by a finite element beam propagation method (FE-BPM).journal articl
従来型落石防護柵の耐衝撃挙動に関する数値解析的検討
Get PDFapplication/pdfIn this paper, a three-dimensional elasto-plastic response analysis on impact loading tests of a full-scale conventional rockfall protection fence was performed, and the applicability of the proposed analysis method was verified by comparing with the experimental results. Furthermore, using the proposed method, a parametric study was conducted to investigate effects of the magnitude of diameter of the falling rock and number of spans on dynamic behavior of the fence under the condition of the same impact energy. The results obtained from this study were as follows: 1) time histories of the dynamic responses can be appropriately estimated by using the proposed method; and 2) effects of the mass of the falling rock and number of spans were numerically clarified.journal articl
Efficient Shape and Topology Optimization Based on Sensitivity Analysis for Optical Waveguide Devices Utilizing Full-Vectorial BPM
Get PDFapplication/pdfWe present a new design approach of shape and topology optimization utilizing the full-vectorial beam propagation method (FV-BPM) so as to achieve efficient design for high-refractive-index contrast optical waveguides and devices based on gradual mode-evolution. In our design approach, material distribution is represented via normalized density parameters, and these design parameters are updated with sensitivity computed based on an adjoint variable method (AVM). The sensitivity analysis method and the design procedure are offered in the specific case where the density method, the AVM, and the FV-BPM based on an alternative direction implicit method (AIDM) are employed. The applicability of our design approach is numerically studied by designing high-refractive-index contrast photonic components which induce polarization rotation: a TM0-to-TE1 mode order converter and a polarization rotator. The results of the design examples indicate that our approach has potential to be suitable for efficient initial design of optical devices based on gradual mode-evolution.journal articl
Design of tapered polarization splitter based on EC-CHFs by full-vectorial FE-BPM using coordinate transformation
Get PDFapplication/pdfWe propose and design a tapered polarization splitter (PS) using the single-polarization property of an elliptical-hole core circular-hole holey fiber (EC-CHF). It is reported that polarization splitting without any crosstalk is enabled using the PS with EC-CHF. In this paper, we show that the mode coupling is enhanced with a tapered PS structure, and the full waveguide separation at the input and output ends can be simultaneously realized. We also propose a full-vectorial finite element beam propagation method using coordinate transformation to efficiently analyze a waveguide whose structure varies along the longitudinal direction. In this approach, computational accuracy and efficiency are greatly improved. (C) 2020 Optical Society of Americajournal articl
Influence of Restrained Condition on Mechanical Properties, Frost Resistance, and Carbonation Resistance of Expansive Concrete
Get PDFapplication/pdfThis paper presents the results of an experimental investigation of the effect of the restrained condition on the mechanical properties, frost resistance, and carbonation resistance of expansive concrete with different water-binder ratios. In this study, length change ratio test, expansion strain test, compressive strength test, mercury intrusion porosimetry test, underwater weighing test, freezing-thawing test, and accelerated carbonation test were performed to evaluate the mechanical properties, pore size distribution, total porosity, and durability of expansive concrete under both restrained and unrestrained conditions. The test results indicate that the length change ratio and expansion strain of the expansive concrete were controlled by the restrained condition. The compressive strength of expansive concrete was enhanced by the triaxial restraining when the amount of expansive additive was 40 kg/m(3) of concrete. Two hypotheses were described to explain the change of pore structure change expansive mortar. The results also indicate that the carbonation resistance and frost resistance were improved by the uniaxial restrained condition. Furthermore, the effect of the restrained condition must be considered to evaluate not only the experimental results of the expansive concrete with a high EX replacement level but also the expansive concrete combining other cement replacement materials.journal articl