An LMI Approach to Discrete-Time Observer Design with Stochastic Resilience

Much of the recent work on robust control or observer design has focused on preservation of stability of the controlled system or the convergence of the observer in the presence of parameter perturbations in the plant or the measurement model. The present work addresses the important problem of stochastic resilience or non-fragility of a discrete-time Luenberger observer which is the maintenance of convergence and/or performance when the observer is erroneously implemented possibly due to computational errors i.e. round off errors in digital implementation or sensor errors, etc. A common linear matrix inequality framework is presented to address the stochastic resilient design problem for various performance criteria in the implementation based on the knowledge of an upper bound on the variance of the random error in the observer gain. Present results are compared to earlier designs for stochastic robustness. Illustrative examples are given to complement the theoretical results

Resilient Observer Design for Discrete-Time Nonlinear Systems with General Criteria

A class of discrete-time nonlinear system and measurement equations having incrementally conic nonlinearities and finite energy disturbances is considered. A linear matrix inequality based resilient observer design approach is presented to guarantee the satisfaction of a variety of performance criteria ranging from simple estimation error boundedness to dissipativity in the presence of bounded perturbations on the gain. Some simulation examples are included to illustrate the proposed design methodology

Stochastically Resilient Observer Design for a Class of Continuous-Time Nonlinear Systems

This work addresses the design of stochastically resilient or non-fragile continuous-time Luenberger observers for systems with incrementally conic nonlinearities. Such designs maintain the convergence and/or performance when the observer gain is erroneously implemented due possibly to computational errors i.e. round off errors in computing the observer gain or changes in the observer parameters during operation. The error in the observer gain is modeled as a random process and a common linear matrix inequality formulation is presented to address the stochastically resilient observer design problem for a variety of performance criteria. Numerical examples are given to illustrate the theoretical results

Robust Nonlinear Feedback Control of Discrete-Time Nonlinear Systems with Mixed Performance Criteria

Abstract-A novel nonlinear state feedback control design is presented for discrete-time nonlinear systems and mixed performance criteria. The purpose behind this new approach is to convert a nonlinear system control design into a convex optimization problem involving state dependent linear matrix inequality solutions. By solving the inequalities at each time step, the optimal control solution is found to satisfy mixed performance criteria guaranteeing quadratic optimality with inherent stability property in combination wit

Development of a miniature Twin Rotary Compressor

In this paper, we will introduce the miniature compressor, which is designed for various applications. Twin rotary compressor structure was adopted to reduced in size and minimize vibration. The weight of the miniature rotary compressor is about 20% that of the reciprocating compressor which has equivalent cooling capacity. To minimize the noise and vibration, the muffler and the cylinder are optimized and torque control algorithm is used for the compressor controller. For a variety of applications, developed compressor is designed for both HBP and LBP condition. Considering the mass-productivity and reliability, IPM type motor is designed

Endoscopist Specialty Is Associated with High-Quality Endoscopy in Korea

Purpose: The present study was aimed to determine whether endoscopist specialty is associated with high-quality endoscopy. Materials and Methods: We prospectively collected endoscopy quality related data based on the Endoscopy Quality Rating Scale (EQRS) of 277 endoscopy units in a hospital setting from the National Cancer Screening Program of Korea in 2009. Gastroenterology medical professors (n=154) from university hospitals visited each endoscopy unit and graded the unit according to the EQRS. The scores from the EQRS were analyzed and compared in relation to endoscopy training during residency and endoscopy subspecialist certification. Results: After excluding data from 3 endoscopy units, EQRS data from 274 endoscopy units were analyzed: 263 esophagogastroduodenoscopy (EGD) screening units and 90 colonoscopy screening units. There were no significant differences in the scores of EQRS with respect to endoscopy training during residency (p=no significance), except for scores of EGDs for "Facility and Equipment" (p=0.030). However, EQRS scores were significantly higher in the endoscopy units where endoscopy subspecialists performed the endoscopies than those where Endoscopy Subspecialists did not perform the endoscopies (p<0.05, except p=0.08 for the "Process" criteria of EGD). Conclusion: Endoscopist specialty is an important determinant of high-quality endoscopy in Korea.This study was supported by a Grant-in-Aid for Cancer Research and Control from the National Cancer Center of Korea (#0960400-1)

Bioanalysis of alpelisib using liquid chromatography–tandem mass spectrometry and application to pharmacokinetic study

Abstract Alpelisib is the first alpha-specific phosphatidylinositol-3-kinase (PI3K) inhibitor indicated for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative, PI3K catalytic subunit alpha-mutated, advanced, or metastatic breast cancer. Substantial attempts have been made to extend its clinical use to other types of cancer. Analytical methods proven to accurately quantify alpelisib would improve the reliability of the preclinical and clinical data of alpelisib. Therefore, we developed and validated a quantification method based on liquid chromatography–tandem mass spectrometry for alpelisib in mouse and human plasma samples. Alpelisib and an internal standard (IS; enzalutamide) were separated from endogenous substances using an XTerra MS C18 column with a linear gradient of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Multiple reaction monitoring transitions for alpelisib and the IS were m/z 442.1 > 328.0 and m/z 465.0 > 209.1, respectively. The calibration curve for alpelisib was confirmed to be linear in the range of 1–2000ng/mL in both mouse and human plasma. The intra- and inter-day accuracy and precision met the acceptance criteria, and no significant matrix effects were observed. Alpelisib was stable under various storage and handling conditions, and the carryover effect was overcome using the injection loop flushing method. We successfully used this assay to study the in vitro metabolic profiles and in vivo pharmacokinetics of alpelisib in mice. Here, to the best of our knowledge, we report for the first time a valid quantitative method for alpelisib in mouse and human plasma, which could aid in providing valuable pharmacokinetic information on alpelisib to increase its clinical availability

A Case of Left Atrial Metastasis From Hepatocellular Carcinoma: Life-Saving Palliative Resection Using Cardiopulmonary Bypass

Hepatocellular carcinoma (HCC) with metastasis to the heart is uncommon. We report a rare case of left atrial metastasis of HCC which was resected palliatively as a live-saving procedure with the use of cardiopulmonary bypass. Despite chemoembolization, which was undertaken 11 times, cardiac metastasis occurred. Moreover, the right and left atria and left ventricle were involved simultaneously. The severe dyspnea improved dramatically after surgery. Following this, the patient underwent systemic chemotherapy and lived a life without recurrence of symptoms associated with mitral valve obstruction