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Improved Hoeffding inequality for dependent bounded or sub-Gaussian random variables

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Probability, Uncertainty and Quantitative Risk 2021年第1期6卷 53-60页

作者： yuta Tanoue Institute for Business and Finance Waseda University3rd FloorBldg.111-6-1 Nishi-WasedaShinjuku-ku169-8050 TokyoJP Full list of author information is available at the end of the article

When addressing various financial problems,such as estimating stock portfolio risk,it is necessary to derive the distribution of the sum of the dependent random *** deriving this distribution requires identifying the joint distribution of these random variables,exact estimation of the joint distribution of dependent random variables is ***,in recent years,studies have been conducted on the bound of the sum of dependent random variables with dependence *** this study,we obtain an improved Hoeffding inequality for dependent bounded ***,we expand the above result to the case of sub-Gaussian random variables.

关键词： α-mixing coefficient Hoeffding inequality Bounded Sub-Gaussian

Seasonal change in sexual differences in nestling size and survival： a framework to evaluate sex-dependent environmental sensitivity in the wild

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Avian Research 2018年第2期9卷 136-143页

作者： Daisuke Nomi Teru yuta Itsuro Koizumi Graduate School of Environmental Science Hokkaido University Sapporo Hokkaido Japan Center for Toki and Ecological Restoration Niigata University Sado Niigata Japan Faculty of Environmental Earth Science Hokkaido University Sapporo Hokkaido Japan

Background: Sexual size dimorphism(SSD) occurs in a wide range of species in birds and other animals, but the magnitude of SSD often varies with environmental conditions. In general, in the developmental stages, the larger sex is more vulnerable to adverse environmental conditions because the larger sex requires more energy than the smaller sex. However, this may not hold true for birds with large brood sizes; the larger sex can acquire more food by suppressing the smaller sex. In addition, most previous studies have been experimental, such as by manipulating clutch size and ectoparasites, which may not reflect natural ***: In the present study, we propose a general framework to assess sexual differences in environmental sensitivity in natural populations. Because environmental conditions change throughout the breeding season, seasonal changes of nestling SSD and sex ratio should reflect sexual differences in environmental sensitivity. We applied this approach to a large dataset(1555 nestlings over 5 years) of Japanese Tits(Parus minor). In this population, the male nestling is generally larger than the female(5% SSD in body weight).Results: We found that the magnitude of SSD(weight, tarsus, wing) and fledgling sex ratio increased both in the beginning and the end of the breeding ***: Our study suggested that female nestlings are more valuable to poor environmental conditions in the relatively fecund species. This study underscores the importance of brood size on sexual differences in environmental stochasticity and our framework encourages comparative analysis among different bird species.

关键词： Brood size Japanese tit Parus minor Seasonal change Sexual size dimorphism

Influence of Diffuser on Aerodynamic Noise of a Forward Curved Fan

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Journal of Thermal Science 2013年第5期22卷 433-438页

作者： Soichi SASAKI Kota SUZUKI yuta Onomichi Hidechito Hayashi Division of System Science Graduate School of Engineering Nagasaki University1-14 Bunkyo-machi Nagasaki 852-8521 Japan Department of Advanced Engineering Graduate School of Engineering Nagasaki University1-14 Bunkyo-machi Nagasaki 852-8521 Japan

In order to clarify the influence of a diffuser on the charactersfics of a forward curved fan, the influence of the bare ratio and the outlet angle on the characteristics of the fan were measured through an experiment performed with an actual fan as well as through a numerical simulation, respectively. The mechanism of the discrete fre- quency noise generated by the separated flow of the diffuser was analyzed. The optimized bare ratio was ap- proximately 17%. The flow separated inside of the diffuser generated discrete frequency noise owing to the inter- action between the reversed flow from the diffuser and the impeller rotating at the blade passing frequency. The diffuser outlet angle influenced the pressure ratio more than that by the bare ratio. Furthermore, it was confirmed that restraining the separation in the diffuser effectively decreases the fan noise.

关键词： Pressure Drop Fan Aerodynamic Noise Internal Flow Separation

Influence of Microstructures on Aerodynamic Characteristics for Dragonfly Wing in Gliding Flight

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Journal of Bionic Engineering 2019年第3期16卷 423-431页

作者： Sheng Zhang Masayuki Ochiai yuta Sunami Hiromu Hashimoto Micro/Nano Technology Center Tokai University 4-1-1 Kitakaname Hiratsuka-city Kanagawa 259-1292 Japan Department of Mechanical Engineering Tokai University 4-1-1 Kitakaname Hiratsuka-city Kanagawa 259-1292 Japan

In this paper, the functionalities of microstructures for dragonfly wing during gliding flight are investigated. Three dragonfly-mimic airfoil-shaped wings with hybrid structures were designed and fabricated as: flat wing, zigzag-edged wing and zigzag-edged wing with pillar structure. Based on the wind tunnel experiments, the zigzag-edged wing structure significantly reduces the drag force in the gliding flight. Moreover, the drag reduction is more effective on the combination of the surface pillar and zigzag-edged structure. In addition, the zigzag-edged wing structure has less influence of Karman vortex street, and the surface pillars reduce the frictional drag and stabilized the streamline in the lower vortex region. Overall, the microstructure of the dragonfly wing is an important element in the aerodynamic study. These findings can enhance the knowledge of insect-mimic wing structure and facilitate the application of Micro Air Vehicle (MAV) in the gliding flight.

关键词： dragonfly wing vein structure aerodynamics gliding biomimetics

Estimating the effective reproduction number of COVID-19 from population-wide wastewater data:An application in Kagawa,Japan

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Infectious Disease Modelling 2024年第3期9卷 645-656页

作者： yuta Okada Hiroshi Nishiura Kyoto University School of Public Health Yoshida-KonoeSakyoKyoto606-8601Japan

Although epidemiological surveillance of COVID-19 has been gradually downgraded globally,the transmission of COVID-19 *** is critical to quantify the transmission dynamics of COVID-19 using multiple datasets including wastewater virus concentration ***,we propose a comprehensive method for estimating the effective reproduction number using wastewater *** wastewater virus concentration data,which were collected twice a week,were analyzed using daily COVID-19 incidence data obtained from Takamatsu,Japan between January 2022 and September *** estimated the shedding load distribution(SLD)as a function of time since the date of infection,using a model employing the delay distribution,which is assumed to follow a gamma distribution,multiplied by a scaling *** also examined models that accounted for the temporal smoothness of viral load measurement *** model that smoothed temporal patterns of viral load was the best fit model(WAIC=2795.8),which yielded a mean estimated distribution of SLD of 3.46 days(95%CrI:3.01–3.95 days).Using this SLD,we reconstructed the daily incidence,which enabled computation of the effective reproduction *** the best fit posterior draws of parameters directly,or as a prior distribution for subsequent analyses,we first used a model that assumed temporal smoothness of viral load concentrations in wastewater,as well as infection counts by date of *** the subsequent approach,we examined models that also incorporated weekly reported case counts as a proxy for weekly incidence *** approaches enabled estimations of the epidemic curve as well as the effective reproduction number from twice-weekly wastewater viral load *** weekly case count data reduced the uncertainty of the effective reproduction *** conclude that wastewater data are still a valuable source of information for inferring the transmission dynamics of COVID-19,and that inferential performance is enhanced when tho

关键词： Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Wastewater-based epidemiology Shedding load distribution'Mathematical model

Up-grading of natural ilmenite ore by combining oxidation and acid leaching

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International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 729-736页

作者： Takehito Hiraki Yuichi Maruyama yuta Suzuki Satoshi Iloh Tetsuya Nagasaka Department of Metallurgy Graduate School of EngineeringTohoku UniversitySendai 980-8579Japan Toho Titanium Co. Ltd.Kanagawa 253-8510Japan Fanuc Co. Ltd.Oshino-muraYamanashi 401-0511Japan Before retirement:Graduate School of Environmental Studies Tohoku UniversitySendai 980-8579Japan

Rutile （TiO2） is heavily used in pigments mid colormlts, mid the most abundmlt source of rutile is ilmeinte. Upon oxidation of ilmeinte, mtile cml be formed wiffl modest energy consumption; furfflermore, after leaching, only a few byproducts are formed. Unfortunate- ly, one drawback is file necessarily long oxidative process of typically used mefflods. In fflis study, we show fflat a fluidized bed reactor cml be used to oxidize ilmeinte ore to rapidly form ruffle mid pseudobrookite （Fe2TiOs） phases. Ilmeinte was oxidized wiffl 5vo1% 02 in Ar at temperatures of 1173 K or 1223 K mid subsequently leached using a diluted H2SO4 solution to dissolve file pseudobrookite phase. The effects of acid concentration, temperature, mid cooling rate after oxidation were investigated. We show fflat file ilmeinte was rapidly oxidized to form rutile mid pseudobrookite phases at 1173 mid 1223 K in a 5vo1% O2/95vo1% Ar environment wifflin 40 min. The fmal maximum mtile yield was 84.2mo1% after leaching in （1 ＋ 1） H2SO4 solution at 393 K for 12 h.

关键词： ilmenite oxidation fluidized bed reactor acid leaching rutile pseudobrookite

Role of atomic-scale thermal fluctuations in the coercivity

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npj Computational Materials 2020年第1期6卷 1084-1090页

作者： yuta Toga Seiji Miyashita Akimasa Sakuma Takashi Miyake National Institute for Materials Science(NIMS) Tsukuba 305-0047Japan Elements Strategy Initiative Center for Magnetic Materials(ESICMM) TsukubaJapan Institute for Solid State Physics University of TokyoKashiwa 277-8581Japan The Physical Society of Japan Tokyo 113-0033Japan Department of Applied Physics Tohoku UniversitySendai 980-8579Japan National Institute of Advanced Industrial Science and Technology(AIST) Tsukuba 305-8568Japan

The microscopic mechanism of coercivity at finite temperature is a crucial issue for permanent *** we present the temperature dependence of the coercivity of an atomistic spin model for the highest-performance magnet Nd_(2)Fe_(14)*** quantitative analysis of the magnetization reversal with thermal fluctuations,we focus on the free energy landscape as a function of the *** free energy is calculated by the replica-exchange Wang–Landau *** approach allows us to address a slow nucleation problem,i.e.,thermal activation effects,in the magnetization *** concretely observed that the thermal fluctuations lead to a downward convexity in the coercivity concerning the ***,through analyzing the microscopic process of the thermal activation(nucleation),we discover the activation volume is insensitive to a magnetic field around the *** insensitivity explains the linear reduction of the free energy barrier by the magnetic field in the nucleation process.

关键词： thermal activation magnetization

Automated estimation of materials parameter from X-ray absorption and electron energy-loss spectra with similarity measures

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npj Computational Materials 2019年第1期5卷 815-821页

作者： yuta Suzuki Hideitsu Hino Masato Kotsugi Kanta Ono Department of Materials Science and Technology Tokyo University of ScienceTokyoJapan High Energy Accelerator Research Organization Institute of Materials Structure ScienceTsukubaJapan The Institute of Statistical Mathematics TokyoJapan Center for Materials Research by Information Integration(CMI2) Research and Services Division of Materials Data and Integrated System(MaDIS)National Institute for Materials Science(NIMS)Tsukuba 305-0047Japan

Materials informatics has significantly accelerated the discovery and analysis of materials in the past *** of the key contributors to accelerated materials discovery is the use of on-the-fly data analysis with high-throughput experiments,which has given rise to the need for accelerated and accurate automated estimation of the properties of *** this regard,spectroscopic data are widely used for materials discovery because these data include essential information about *** important requirement for the realisation of the automated estimation of materials parameters is the selection of a similarity measure,or kernel *** required measure should be robust in terms of peak shifting,peak broadening,and ***,the determination of appropriate similarity measures for spectra and the automated estimation of materials parameters from these spectra currently remain *** examined major similarity measures to evaluate the similarity of both X-ray absorption and electron energy-loss *** similarity measures show good correspondence with the materials parameter,that is,the crystal-field parameter,in all *** Pearson's correlation coefficient was the highest for the robustness against noise and peak *** obtained the regression model for the crystal-field parameter 10 Dq from the similarity of the *** regression model enabled the materials parameter,that is,10 Dq,to be automatically estimated from the *** regard to research progress in similarity measures,this methodology would make it possible to extract the materials parameter from a large-scale dataset of experimental data.

关键词： materials similarity parameter

Quantitative determination of erlotinib in human serum using competitive enzyme-linked immunosorbent assay

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Journal of Pharmaceutical Analysis 2018年第2期8卷 119-123页

作者： yuta Yamamoto Tetsuya Saita yutaro Yamamoto Masashi Shin Applied Life Science Department Faculty of Biotechnology and Life Science Sojo University

A selective and sensitive competitive enzyme-linked immunosorbent assay(ELISA) method was developed and validated for the quantification of erlotinib in 50 mL of samples of human serum. Anti-erlotinib serum was obtained by immunizing mice with an antigen conjugated with bovine serum albumin and 3,4-bis(2-methoxyethoxy)benzoic acid using the N-succinimidyl ester method. Enzyme labeling of erlotinib with horseradish peroxidase was similarly performed using 3,4-bis(2-methoxyethoxy)benzoic acid. A simple competitive ELISA for erlotinib was developed using the principle of direct competition between erlotinib and the enzyme marker for anti-erlotinib antibody, which had been immobilized on the plastic surface of a microtiter plate. Serum erlotinib concentrations lower than 40 ng/mL were reproducibly measurable using the ELISA. This ELISA was specific to erlotinib and showed very slight cross-reactivity(6.7%) with a major metabolite, O-desmethyl erlotinib. Using this assay, drug levels were easily measured in the blood of mice after oral administration of erlotinib at a single dose of 30 mg/kg. ELISA should be used as a valuable tool for therapeutic drug monitoring and in pharmacokinetic studies of erlotinib.

关键词： Erlotinib Enzyme-linked immunosorbent assay O-desmethyl erlotinib Tyrosine-kinase inhibitor