ウィグナー分布とフーリエ変換のハイブリッドスペクトル解析法による音声信号解析

Wigner Distribution (WD) has recently attracted attention from many researchers as a tool for time-frequency signal analysis. WD offers higher frequency resolution but with interference terms for multiple frequency components. A method of spectral analysis as a hybrid of WD and FT is proposed for time-varying signals. The method offers higher frequency resolution with neither interference terms nor aliasing. This method is applied to measurement of a voice signal.application/pdfdepartmental bulletin pape

釈論大江千里集（十）

This paper is an investigation and interpretation (釈論) of ‘Oe no Chisato-shu’ (大江千里集) which is an anthology of Waka (和歌＝ancient Japanese poems) by Oe himself.In this anthology, as usually called Kudai-waka (句題和歌), each Waka is given one phrase poetic title from Kanshi (漢詩＝ancient Chinese poem) selected by Oe.The authors of this paper think that the mutual relations between expressions in both Waka and Kanshi have various patterns. So，the central purpose of our investigation is to concretely explicate the actual condition of all these patterns． And first,this paper treats of Waka No.36～No.40 of ‘Oe no Chisato-shu’.application/pdfdepartmental bulletin pape

CrB,CrB₂,Cr₂N,CrSi₂セラミックスのホットプレス焼結とその機械的・電気的特性

In order to investigate the mechanical and electrical properties of CrB, CrB₂, Cr₂N, and CrSi₂ of Cr-based ceramics with good oxidation resistance, hot press (HP) sintering was performed under the condition of pressure of 28.2 MPa for 3.6 ks at a　temperature of 85% of the melting point [℃] in a Ar atmosphere using each pure powder. As a result, CrSi2 has good mechanical properties as a whole, with a flexural strength of 343 MPa, a fracture toughness value of 3.44 MPa∙m1/2, and a surface roughness (Ra) of 70.0 nm. On the other hand, as for the electrical characteristics, CrB₂ had a high electrical conductivity of 2.44 MS/m, and CrSi₂ had a low one of 0.072 MS/m. The oxidation temperature of these ceramics is 1000°C or higher. Therefore, Cr-based ceramics are suitable for materials in fields where oxidation resistance is required.application/pdfdepartmental bulletin pape

六方晶フェライトBa(Fe1-xScx)12O19の磁気相図とアンチフェロ磁気相の磁気構造解析

公立諏訪東京理科大学博士(工学）2021doctoral thesi

クロスセクター効果に基づく地域公共交通システム評価手法の検討～飯山市を対象として～

In local cities, public transportation systems are not profitable, so local governments make up the deficit. To evaluate the value of public transportation systems, it is ecessary to use not only quantitative indicators such as the number of users and revenues, but also non -quantifiable indicators such as residents' satisfaction and social benefits. Therefore, this study compares the current expenditures with the amount of increase in social burdens by sector that would be required by eliminating the public transportation system. Furthermore, we aim to establish a new public transportation ystem evaluation method by calculating the cross-sector effects of a regional public transportation system for Iiyama City, Nagano Prefecture.application/pdfdepartmental bulletin pape

情報エレクトロニクス系研究発表題目一覧

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ロボコンプロジェクト2021活動報告

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光触媒を利用したCFRPリサイクルに関する研究

An experiment was conducted to recover carbon fiber from CFRP by recycling. CFRP small sheet pieces and spherical media were placed in a cylindrical can and held at 50℃ for 0.5 hours at 12 rpm to accelerate decomposition. As the decomposition media, TiO₂, Al₂O₃, ZrO₂, Ti and none(no media), which were sintered after spherical molding, and those with anatase type TiO₂ coating were used. Recycling results were evaluated by SEM observation, elemental analysis, and line elemental analysis.As a result, the good results were obtained in the case of rutile type iO₂(r), that is, without the coating of anatase type TiO2 and in the case of None media, both of which had a C element concentration of about 99% and an O element one of about 1%. The shape of the recovered carbon fiber did not change the figure.application/pdfdepartmental bulletin pape

Ti粉末加圧焼結時の超音波付与による高密度化

The sintering promotion effect was investigated based on the both cases where 28kHz and 20kHz ultrasonic waves were applied and not applied during hot-press sintering of Ti powder. The promotion effect was valuated by relative density, tensile strength, Vickers hardness, electrical conductivity, and SEM microstructure observation. As a result, when the hot-press pressure was 40MPa and the sintering time was 10 minutes in the Ar inert gas atmosphere, great promotion was obtained at 800°C. For example, the relative density could be improved from 84.4% to 95.6% (at 20 kHz), and the tensile strength could be improved from 291MPa to 592MPa (at 20kHz). However, at a lower temperature at 600 and 700°C and a higher temperature of 900°C, the improvement range became smaller.application/pdfdepartmental bulletin pape

ホットプレス法によるSiC/VGCF短繊維強化複合セラミックス焼結体の作製と特性 ‐VGCF均一分散溶液の選定と複合体特性評価‐

A composite was hot-pressed by adding 3.23 mass% of short fiber VGCF (vapor phase carbon nano-fiber) having a diameter of about 0.15 μm to SiC ceramics. VGCF was present at the grain boundaries of SiC while maintaining the fiber shape in the composite. By dispersing VGCF with SiC using an aqueous agar solution, the mechanical and electrical characteristics could be improved. Compared with the case where VGCF was not added, the bending strength, the fracture toughness and the lectrical conductivity were improved by about 1.92 times, 1.46 times and 400 times, respectively.application/pdfdepartmental bulletin pape