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Joint input–output identiﬁcation of unstable systems with kernel regularization

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Control Theory and Technology 2024年第2期22卷 195-202页

作者： Yusuke fujimoto Toshiharu Sugie Department of Environmental Engineering the University of Kitakyushu1-1HibikinoWakamatsu-kuKitakyushu 8080135FukuokaJapan Professor Emeritus Kyoto UniversityYoshida-HonmachiSakyo-kuKyoto 6068501KyotoJapan

This paper discusses closed-loop identiﬁcation of unstable *** particular,weﬁrst apply the joint input–output identiﬁcation method and then convert the identiﬁcation problem of unstable systems into that of stable systems,which can be tackled by using kernel-based regularization *** propose to identify two transfer functions by kernel regularization,the one from the reference signal to the input,and the one from the reference signal to the *** these transfer functions are stable,kernel regularization methods can construct their accurate *** the model of unstable system is constructed by ratio of these *** effectiveness of the proposed method is demonstrated by a numerical example and a practical experiment with a DC motor.

关键词： Closed-loop identification Kernel regularization Joint input-output identification

Energy conversion due to non-ideal electric field in separatrix region of magnetotail reconnection

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Earth and Planetary Physics 2024年第5期8卷 787-796页

作者： YiNan Liu Keizo fujimoto JianQiang Wang XiaoChuan Duan School of Space and Environment Beihang University Key Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information Technology School of Automation Science and Electrical Engineering Beihang University

A recent satellite observation has revealed the presence of energy conversion in the separatrix region(SR) of magnetotail reconnection, driven by perpendicular components. We investigated this phenomenon by means of particle-in-cell simulations in twodimensional(2D) and three-dimensional(3D) systems. Our result indicates that in the 2D simulation, energy conversion in the SR is dominated by parallel components, with the main influencing factor being the parallel electric field, which is not consistent with the observation. However, a case that is similar to the observation is found in the 3D simulation, suggesting that the observation result may be attributed to the 3D characteristics. Our findings provide a potential explanation for the satellite observation.

关键词： magnetic reconnection energy conversion PIC simulation separatrix region

A unified multi-view multi-person tracking framework

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Computational Visual Media 2024年第1期10卷 137-160页

作者： Fan Yang Shigeyuki Odashima Sosuke Yamao Hiroaki fujimoto Shoichi Masui Shan Jiang Nanjing University China 不详 Fujitsu Research

Despite significant developments in 3D multi-view multi-person (3D MM) tracking, current frameworks separately target footprint tracking, or pose tracking. Frameworks designed for the former cannot be used for the latter, because they directly obtain 3D positions on the ground plane via a homography projection, which is inapplicable to 3D poses above the ground. In contrast, frameworks designed for pose tracking generally isolate multi-view and multi-frame associations and may not be sufficiently robust for footprint tracking, which utilizes fewer key points than pose tracking, weakening multi-view association cues in a single frame. This study presents a unified multi-view multi-person tracking framework to bridge the gap between footprint tracking and pose tracking. Without additional modifications, the framework can adopt monocular 2D bounding boxes and 2D poses as its input to produce robust 3D trajectories for multiple persons. Importantly, multi-frame and multi-view information are jointly employed to improve association and triangulation. Our framework is shown to provide state-of-the-art performance on the Campus and Shelf datasets for 3D pose tracking, with comparable results on the WILDTRACK and MMPTRACK datasets for 3D footprint tracking.

关键词： multi-camera multi-person tracking pose tracking footprint tracking triangulation spatiotemporal clustering

Non-improvement of atrophic gastritis in cases of gastric cancer after successful Helicobacter pylori eradication therapy

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World Journal of Clinical Cases 2024年第14期12卷 2342-2349页

作者： Yuto Suzuki Yasumi Katayama Yo fujimoto Ikuhiro Kobori Masaya Tamano Department of Gastroenterology Dokkyo medical University Saitama Medical CenterKoshigayaSaitama 343-8555Japan Endoscopy Center Dokkyo Medical University Saitama Medical CenterKoshigayaSaitama 343-8555Japan

BACKGROUND Helicobacter pylori(***)infection is closely related to the development of gastric cancer(GC).However,GC can develop even after *** ***,it would be extremely useful if GC could be predicted after *** Kyoto classification score for gastritis(GA)is closely related to cancer ***,how the score for GC changes after eradication before onset is not well *** To investigate the characteristics of the progression of Kyoto classification scores for GC after *** *** Eradication of *** was confirmed in all patients using either the urea breath test or the stool antigen *** Kyoto classification score of GC patients was evaluated by endoscopy at the time of event onset and three years *** ad-dition,the modified atrophy score was evaluated and compared between the GC group and the control GA *** In total,30 cases of early GC and 30 cases of chronic GA were *** pathology of the cancer cases was differentiated adenocarcinoma,except for one case of undifferentiated *** total score of the Kyoto classifi-cation was significantly higher in the GC group both at the time of cancer onset and three years earlier(4.97 vs 3.73,P=0.0034;4.2 vs 3.1,P=0.0035,respectively).The modified atrophy score was significantly higher in the GC group both at the time of cancer onset and three years earlier and was significantly improved only in the GA group(5.3 vs 5.3,P=0.5;3.73 vs 3.1,P=0.0475,respectively).CONCLUSION The course of the modified atrophy score is useful for predicting the onset of GC after *** with severe atrophy after *** eradication require careful monitoring.

关键词： Helicobacter pylori Kyoto classification Gastritis Eradication therapy Gastric cancer

Pneumoparotid with imaging findings:A case report and review of literature

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World Journal of Clinical Cases 2024年第34期12卷 6705-6714页

作者： Wakako Kubota Makiko Kyan-Onodera Yasuomi fujimoto Akihiro Sakuma Ryuji Katada Chihiro Sugiura Department of Radiology Sapporo Tokushukai HospitalSapporo 0040041HokkaidoJapan Department of Dentistry and Oral Surgery Sapporo Tokushukai HospitalSapporo 0040041HokkaidoJapan

BACKGROUND Pneumoparotid is a rare disease associated with retrograde airflow into the ductal *** is no established treatment for this disease,which has no known *** puffing and playing wind instruments are known to be the causes of this *** SUMMARY We managed a case,in which pneumoparotid suddenly recurred 4 months after surgery for purulent *** patient did not report any obvious etiological factors,such as mouth puffing or playing a wind *** reviewed 128 articles(from 1941 to 2023)that reported on a total of 166 patients with pneumoparotid,including the patient from the present case report,with imaging *** is the first reported case of pneumoparotid following surgery for purulent *** etiology in our case was classified as *** Imaging findings could be sufficient for accurate pneumoparotid diagnoses and the exclusion of complications;computed tomography could be useful.

关键词： Computed tomography Imaging findings Parotid gland Pneumoparotid Pneumoparotitis Case report

Approximate Solutions to the Hamilton-Jacobi Equations for Generating Functions

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Journal of Systems Science & Complexity 2020年第2期33卷 261-288页

作者： HAO Zhiwei fujimoto Kenji ZHANG Qiuhua Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbin 150001China Department of Aeronautics and Astronautics Kyoto UniversityC3 Bldg.Kyotodaigaku-katsuraNishikyo-kuKyoto 615-8540Japan

For a nonlinear finite time optimal control problem,a systematic numerical algorithm to solve the Hamilton-Jacobi equation for a generating function is proposed in this *** algorithm allows one to obtain the Taylor series expansion of the generating function up to any prescribed order by solving a sequence of first order ordinary differential equations ***,the coefficients of the Taylor series expansion of the generating function can be computed exactly under a certain technical *** a generating function is found,it can be used to generate a family of optimal control for different boundary *** the generating function is computed off-line,the on-demand computational effort for different boundary conditions decreases a lot compared with the conventional *** is useful to online optimal trajectory generation *** examples illustrate the effectiveness of the proposed algorithm.

关键词： Generating functions Hamilton-Jacobi equations optimal control Taylor series expansion two-point boundary-value problems

Molecular dynamics simulation of the A-DNA to B-DNA transition in aqueous RbCl solution

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Science China Chemistry 2013年第4期56卷 524-532页

作者： YU YangXin fujimoto Shintaro Laboratory of Chemical Engineering Thermodynamics Department of Chemical Engineering Tsinghua University

Unrestrained molecular dynamics （MD） simulations have been carded out to characterize the stability of DNA conformations and the dynamics of A-DNA^B-DNA conformational transitions in aqueous RbC1 solutions. The PARM99 force field in the AMBER8 package was used to investigate the effect of RbC1 concentration on the dynamics of the A^B conformational tran- sition in the DNA duplex d（CGCGAATTCGCG）2. Canonical A- and B-form DNA were assumed for the initial conformation and the final conformation had a length per complete turn that matched the canonical B-DNA. The DNA structure was moni- tored for 3.0 ns and the distances between the C5＇ atoms were obtained from the simulations. It was found that all of the double stranded DNA strands of A-DNA converged to the structure of B-form DNA within 1.0 ns during the unrestrained MD simula- tions. In addition, increasing the RbC1 concentration in aqueous solution hindered the A^B conformational transition and the transition in aqueous RbC1 solution was faster than that in aqueous NaC1 solution for the same electrolyte strength. The effects of the types and concentrations of counterions on the dynamics of the A^B conformational transition can be understood in terms of the variation in water activity and the number of accumulated counterions in the major grooves of A-DNA. The ru- bidium ion distributions around both fixed A-DNA and B-DNA were obtained using the restrained MD simulations to help ex- plain the effect of RbC1 concentration on the dynamics of the A^B conformational transition.

关键词： DNA conformational transition molecular dynamics aqueous RbCI solution

Simulation study on dynamics of A- to B-form transition in aqueous DNA solution:Effect of alkali metal counterions

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Science China Chemistry 2013年第12期56卷 1735-1742页

作者： YU YangXin fujimoto Shintaro Laboratory of Chemical Engineering Thermodynamics Department of Chemical EngineeringTsinghua University

DNA and its conformational transition can be used to design nanometer-scale structures, nano-tweezers and nanomechanical devices. Experiments and molecular simulations have been used to study the concentration effect on the A-DNA→B-DNA conformational transition, but a systematical investigation on counterion effect on the dynamics of this transition has not been reported up to now. In present work, restrained and unrestrained molecular dynamics （MD） simulations have been performed to characterize the stability of DNA conformations and the dynamics of A-DNA→B-DNA transitions in aqueous solutions with different alkali metal counterions. The DNA duplex d（CGCGAATTCGCG）2, coion Cl- and counterions Li＋, Na＋, K＋, Rb＋ and Cs~ as well as water molecule were considered using the PARM99 force field in the AMBER8 package. It was found that B-form DNA is more stable than A-form DNA in aqueous electrolyte solutions with different alkali metal counterions. In- creasing KCI concentration in solution hinders the A-DNA^B-DNA transition and the transition times for different alkali metal counterions conform to neither the simple sequence related to naked ion size nor to hydrated diameter, but an apparently abnormal sequence of K＋〈 Rb＋〈 Cs＋〈 Na＋〈 Li＋. This abnormal sequence can be well understood in terms of an electrostatic model based on the effective cation diameters and the modified mean-spherical approximation （MMSA）. The present results provide valuable information for the design of DNA-based nanomaterials and nanodevices.

关键词： A-DNA B-DNA conformational transition alkali metal ion molecular dynamics

Large Eddy Simulation of Swirling Jet in a Bluff-Body Burner

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Journal of Thermal Science 2005年第1期14卷 28-33页

作者： Yohei fujimoto Yuzo INOKUCHI Nobuhiko YAMASAKI Department of Aeronautics and Astronautics Kyushu-University 6-10-1HakozakiHigashikuFukuoka812-8581JapanDepartment of Aeronautics and Astronautics Kyushu-University 6-10-1HakozakiHigashikuFukuoka812-8581JapanDepartment of Aeronautics and Astronautics Kyushu-University 6-10-1HakozakiHigashikuFukuoka812-8581Japan

The large eddy simulation (LES) is applied to an unconfined swirling flow of an air surrounding a bluff-body having a central jet of air, and the complicated flowfield that involves the recirculation and vortex breakdown is investigated. The Smagorinsky model is used as the sub-grid scale model. The results of the present numerical simulation are compared with the experimental data of the mean and stochastic root mean square (RMS) variations of two velocity components. Although the inflow conditions are specified in a simple manner, the obtained numerical results are in reasonable agreement with the experiments, except for a part of RMS variation values near downstream of the bluff body. The present numerical calculations can successfully reproduce the two characteristics of the flow, i.e., an upstream recirculation zone established just downstream of the burner plane and the additional recirculation zone established at the more downstream location.

关键词： large eddy simulation swirl bluff-body recirculation.