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Yahagi Musashi,Omi Kyuma,Maeda Takuma 대한마취통증의학회 2022 Korean Journal of Anesthesiology Vol.75 No.2
Background: Noninvasive cardiac output (CO) measured using ClearSight™ eliminates the need for intra-arterial catheter insertion. The purpose of this study was to examine the accuracy of non-invasive CO measurement in patients with severe aortic valve stenosis (AS). Methods: Twenty-eight patients undergoing elective transcatheter aortic valve implantation were prospectively enrolled in this study. The CO was simultaneously measured twice before and twice after valve deployment (total of four times) per patient, and the CO was compared between the ClearSight (COClearSight) system and the pulmonary artery catheter (PAC) thermodilution (COTD) method as a reference. The Bland-Altman analysis was used to compare the percentage errors between the methods. Results: A total of 112 paired data points were obtained. The percentage error between the COClearSight and COTD was 43.1%. The paired datasets were divided into the following groups according to the systemic vascular resistance index (SVRI): low (< 1,200 dyne s/cm5/m2) and normal (1,200–2,500 dyne s/cm5/m2). The percentage errors were 44.9% and 49.4%, respectively. The discrepancy of CO between COClearSight and COTD was not significantly correlated with SVRI (r = −0.06, P < 0.001). The polar plot analysis showed the trending ability of the COClearSight after artificial valve deployment was 51.1% which below the acceptable cut-off (92%). Conclusions: The accuracy and the trending ability of the ClearSight CO measurements were not acceptable in patients with severe AS. Therefore, the ClearSight system is not interchangeable with the PAC thermodilution for determining CO in this population.
Direct tuning of PID controller and reference model with input constraint
Shuichi Yahagi,Itsuro Kajiwara 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10
The direct tuning of controller parameters based on data-driven control has attracted considerable attention because of its simple controller design. In this study, we proposed a direct tuning method based on a fictitious reference signal to obtain controller and reference model parameters. In the method, predicted input/output data with respect to controller parameters are used. The predicted data with pole information are obtained based on instability detecting-fictitious reference iterative tuning, which can ensure bounded-input, bounded-output stability. We derived a new objective function with constraints using the predicted data to automatically obtain controller and reference model parameters to perform a fast response under model matching and input constraints. The function consists of an evaluation part in which the fastest responsive reference model is requested and constraint parts that include model-matching errors and input amounts. A simulation was performed to verify the effectiveness of the proposed method. The results showed that the proposed method provided controller and reference model parameters for the model matching and input constraints from one-shot data without trial and error.
Motoya Suzuki,Shuichi Yahagi 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11
Vehicle velocity control has attracted significant research attention for autonomous driving applications. To achieve reliable autonomous driving, the desired velocity control should be realized. However, it is challenging to realize the desired control response because it is difficult to identify the accurate vehicle model. A feedback controller based on the nominal model cannot realize the desired velocity controls when the nominal error is extremely large. In this study, we propose a velocity control based on a model error compensator (MEC) and fictitious reference iterative tuning (FRIT). The proposed method can calculate the control signal to minimize the relative error between the closed-loop system and the normative model. By designing the tunable parameters of the MEC in the framework of FRIT, the desired control response can be achieved using one-shot experimental data. We verified the proposed method using a vehicle dynamics blockset.
Long-Term Outcomes of Using Endoscopic Submucosal Dissection to Treat Early Gastric Cancer
Toshihiro Nishizawa,Naohisa Yahagi 거트앤리버 소화기연관학회협의회 2018 Gut and Liver Vol.12 No.2
Endoscopic submucosal dissection (ESD) is becoming the main procedure for the resection of early gastric cancer (EGC). The absolute indications for treating EGC with endoscopic resection were established by the Japanese Gastric Cancer Association and have been generally accepted. However, the absolute indications for treating EGC are rather strict, and expanded indications have been developed. Many studies have reported favorable long-term outcomes for patients who received curative resection for the expanded indication. ESD preserves the stomach, thereby improving patients’ quality of life compared to surgery; however, a generally higher incidence of metachronous gastric cancer has been reported after ESD for EGC. Therefore, clinicians must pay careful attention during surveillance endoscopy, even after a curative ESD.
Han, Donghee,Torii, Sho,Yahagi, Kazuyuki,Lin, Fay Y.,Lee, Ji Hyun,Rizvi, Asim,Gransar, Heidi,Park, Mahn-Won,Roudsari, Hadi Mirhedayati,Stuijfzand, Wijnand J.,Baskaran, Lohendran,ó,Hartaigh, Br&i Elsevier Scientific Publ. Co 2018 Atherosclerosis Vol. No.
<P><B>Abstract</B></P> <P><B>Background and aims</B></P> <P>Recent advancements in coronary computed tomography angiography (CCTA) have allowed for the quantitative measurement of high-risk lipid rich plaque. Determination of the optimal threshold for Hounsfield units (HU) by CCTA for identifying lipid rich plaque remains unknown. We aimed to validate reliable cut-points of HU for quantitative assessment of lipid rich plaque.</P> <P><B>Methods</B></P> <P>8 post-mortem sudden coronary death hearts were evaluated with CCTA and histologic analysis. Quantitative plaque analysis was performed in histopathology images and lipid rich plaque area was defined as intra-plaque necrotic core area. CCTA images were analyzed for quantitative plaque measurement. Low attenuation plaque (LAP) was defined as any pixel < 30, 45, 60, 75, and 90 HU cut-offs within a coronary plaque. The area of LAP was calculated in each cross-section.</P> <P><B>Results</B></P> <P>Among 105 cross-sections<B>,</B> 37 (35.2%) cross-sectional histology images contained lipid rich plaque. Although the highest specificity for identifying lipid rich plaque was shown with <30 HU cut-off (88.2%), sensitivity (e.g. 55.6% for <75 HU, 16.2% for <30 HU) and negative predictive value (e.g. 75.9% for <75 HU, 65.9% for <30 HU) tended to increase with higher HU cut-offs. For quantitative measurement, <75 HU showed the highest correlation coefficient (0.292, <I>p</I> = 0.003) and no significant differences were observed between lipid rich plaque area and LAP area between histology and CT analysis (Histology: 0.34 ± 0.73 mm<SUP>2</SUP>, QCT: 0.37 ± 0.71 mm<SUP>2</SUP>, <I>p</I> = 0.701).</P> <P><B>Conclusions</B></P> <P>LAP area by CCTA using a <75 HU cut-off value demonstrated high sensitivity and quantitative agreement with lipid rich plaque area by histology analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lipid rich plaques are related to future risk of acute coronary syndrome. </LI> <LI> Quantitative coronary plaque (QCT) analysis enables to quantify lipid rich plaques. </LI> <LI> 75 HU is a reliable cut-off for quantification of lipid rich plaque in QCT analysis. </LI> </UL> </P>
Emiko Hazama,Hiroshi Yahagi 한국문화경제학회 2010 문화경제연구 Vol.13 No.1
In this paper the difficulties for public cultural centers to achieve their missions are illustrated by the comparative study of two big music halls established by prefectures (the Biwako Hall Center for the Performing Arts in Shiga and Hyogo Performing Arts Center). Reflecting the changes of economy and society, the expectation of stakeholders (prefectures as establisher or people as taxpayers) towards public cultural halls changes constantly;the missions of public cultural halls to meet their satisfaction becomes a “moving target”. Baumol/Bowen (Performing Arts: The Economic Dilemma) described the justification of financial supports toward public cultural facilities with “4 criteria of externality of culture”. However, also in this paper the difficulty for public cultural halls to achieve these 4 criteria at the same time under the condition of a moving target is illustrated. There are the previous studies that examine whether a public cultural hall satisfies its missions and compare the missions between various public cultural halls. But there is not the study that focuses on that the missions of public cultural halls with a point of view that it is intrinsically movable. This paper studies public music halls supported mainly by tax. However, by making comparative studies on public art museums or public cultural halls that operate mainly with donation such as those in the USA, the results of this study can be deepen further.