PFC design method for SAC based on the stability theorem of the descriptor system and frequency response fitting

Simple adaptive control (SAC) is a control method that maintains control performance despite perturbations of a plant. However, there is a problem in that the vibratory output occurs in the transient response when SAC is applied to a vibration system which includes anti-resonance modes. The occurrence of the output depends on the structure of SAC and the output is caused by the vibratory input corresponding to the anti-resonance frequency. In order to overcome the problem, a method using an appropriate parallel feedforward compensator (PFC) is proposed. In the proposed method, an effective PFC is designed such that the gain of an augmented system is matched to that of a desired model under the ASPR condition of the augmented system. A design problem is described by LMI/BMI conditions. The problem using LMI/BMI conditions is solved by an iterative procedure. However, the leading coefficient of the PFC must be given a priori in order to guarantee the ASPR property, which provides some restrictions for applications of the proposed method. In the present paper, an improved method to overcome the abovementioned restrictions is proposed using the stability theorem of the descriptor system. The effectiveness of the proposed method is verified through numerical simulations and experiments.ArticleMechanical Engineering Journal. 2(3):14-00547 (2015)journal articl

Multirate and Model Predictive Control of a Pneumatic Isolation Table with a Discrete Actuator

ArticleIFAC-PapersOnLine. 52(15): 442-447. (2019)journal articl

Experimental verification of multirate and Model Predictive Control for discrete-valued control systems

ArticleMechanical Engineering Journal. 8(5): 21-00043 (2021)journal articl

Control design for a pneumatic isolation table including different time delays dependent on control input polarity

ArticleIFAC-PapersOnLine. 50(1): 6029-6034. (2017)journal articl

Improved Path Planning of the Blade for an Automatic Spinach Harvester

ArticleIFAC-PapersOnLine. 53(2): 15816-15823. (2020)journal articl

Vaporized Hydrogen Peroxide and Ozone Gas Synergistically Reduce Prion Infectivity on Stainless Steel Wire

Prions are infectious agents causing prion diseases, which include Creutzfeldt–Jakob disease (CJD) in humans. Several cases have been reported to be transmitted through medical instruments that were used for preclinical CJD patients, raising public health concerns on iatrogenic transmissions of the disease. Since preclinical CJD patients are currently difficult to identify, medical instruments need to be adequately sterilized so as not to transmit the disease. In this study, we investigated the sterilizing activity of two oxidizing agents, ozone gas and vaporized hydrogen peroxide, against prions fixed on stainless steel wires using a mouse bioassay. Mice intracerebrally implanted with prion-contaminated stainless steel wires treated with ozone gas or vaporized hydrogen peroxide developed prion disease later than those implanted with control prion-contaminated stainless steel wires, indicating that ozone gas and vaporized hydrogen peroxide could reduce prion infectivity on wires. Incubation times were further elongated in mice implanted with prion-contaminated stainless steel wires treated with ozone gas-mixed vaporized hydrogen peroxide, indicating that ozone gas mixed with vaporized hydrogen peroxide reduces prions on these wires more potently than ozone gas or vaporized hydrogen peroxide. These results suggest that ozone gas mixed with vaporized hydrogen peroxide might be more useful for prion sterilization than ozone gas or vaporized hydrogen peroxide alone

Use of the index of pulmonary vascular disease for predicting long-term outcome of pulmonary arterial hypertension associated with congenital heart disease

AimsLimited data exist on risk factors for the long-term outcome of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD-PAH). We focused on the index of pulmonary vascular disease (IPVD), an assessment system for pulmonary artery pathology specimens. The IPVD classifies pulmonary vascular lesions into four categories based on severity: (1) no intimal thickening, (2) cellular thickening of the intima, (3) fibrous thickening of the intima, and (4) destruction of the tunica media, with the overall grade expressed as an additive mean of these scores. This study aimed to investigate the relationship between IPVD and the long-term outcome of CHD-PAH.MethodsThis retrospective study examined lung pathology images of 764 patients with CHD-PAH aged <20 years whose lung specimens were submitted to the Japanese Research Institute of Pulmonary Vasculature for pulmonary pathological review between 2001 and 2020. Clinical information was collected retrospectively by each attending physician. The primary endpoint was cardiovascular death.ResultsThe 5-year, 10-year, 15-year, and 20-year cardiovascular death-free survival rates for all patients were 92.0%, 90.4%, 87.3%, and 86.1%, respectively. The group with an IPVD of ≥2.0 had significantly poorer survival than the group with an IPVD <2.0 (P = .037). The Cox proportional hazards model adjusted for the presence of congenital anomaly syndromes associated with pulmonary hypertension, and age at lung biopsy showed similar results (hazard ratio 4.46; 95% confidence interval: 1.45–13.73; P = .009).ConclusionsThe IPVD scoring system is useful for predicting the long-term outcome of CHD-PAH. For patients with an IPVD of ≥2.0, treatment strategies, including choosing palliative procedures such as pulmonary artery banding to restrict pulmonary blood flow and postponement of intracardiac repair, should be more carefully considered