Adaptive Torque Estimation for an IPMSM with Cross-Coupling and Parameter Variations

This paper presents a new adaptive torque estimation algorithm for an interior permanent magnet synchronous motor (IPMSM) with parameter variations and cross-coupling between d- and q-axis dynamics. All cross-coupled, time-varying, or uncertain terms that are not part of the nominal flux equations are included in two equivalent mutual inductances, which are described using the equivalent d- and q-axis back electromotive forces (EMFs). The proposed algorithm estimates the equivalent d- and q-axis back EMFs in a recursive and stability-guaranteed manner, in order to compute the equivalent mutual inductances between the d- and q-axes. Then, it provides a more accurate and adaptive torque equation by adding the correction terms obtained from the computed equivalent mutual inductances. Simulations and experiments demonstrate that torque estimation errors are remarkably reduced by capturing and compensating for the inherent cross-coupling effects and parameter variations adaptively, using the proposed algorithm.111Ysciescopu

Incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer

Background: Subsyndromal delirium, a condition in which patients exhibit some, but not all, of the symptoms of delirium, can negatively affect the outcomes of patients with cancer. However, the incidence of subsyndromal delirium in patients with gastric cancer is unknown. Here, we investigated the incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer. Methods: We recruited consecutive patients with gastric cancer who were scheduled for curative resection at a tertiary hospital. Patients' subsyndromal delirium symptoms were serially assessed preoperatively and 1, 2, 3, and 7 days postoperatively using the Delirium Rating Scale-Revised-98 (DRS-R-98). A DRS-R-98 score of 8-14 at any postoperative assessment was considered to indicate subsyndromal delirium. Sociodemographic and pre-/intraoperative clinical data were also assessed. Logistic regression analyses were used to determine the associated risk factors. Results: Data were analysed from 163 out of 217 eligible patients. Postoperative delirium occurred in one patient (0.6%) and subsyndromal delirium occurred in 19 patients (11.7%). Age >= 70 years (odds ratio, [OR] 3.85; 95% confidence interval [0], 136-10.92; p = 0.011) and education level <= 9 years (OR, 3.98; 95% CI, 139-11.41; p= 0.010) were independent risk factors of subsyndromal delirium after adjusting for preoperative cognitive function. Other pre-/intra-operative variables including anxiety/depression, poor sleep quality, and anaesthesia duration were not associated with subsyndromal delirium. Conclusions: In contrast to the low incidence of delirium among patients undergoing curative resection of gastric cancer, a substantial proportion of such patients experienced subsyndromal delirium. Considering the prognostic implications, more careful detection and management of subsyndromal delirium may be warranted in patients with gastric cance

Adaptive Torque Estimation for an IPMSM with Cross-Coupling and Parameter Variations

This paper presents a new adaptive torque estimation algorithm for an interior permanent magnet synchronous motor (IPMSM) with parameter variations and cross-coupling between d- and q-axis dynamics. All cross-coupled, time-varying, or uncertain terms that are not part of the nominal flux equations are included in two equivalent mutual inductances, which are described using the equivalent d- and q-axis back electromotive forces (EMFs). The proposed algorithm estimates the equivalent d- and q-axis back EMFs in a recursive and stability-guaranteed manner, in order to compute the equivalent mutual inductances between the d- and q-axes. Then, it provides a more accurate and adaptive torque equation by adding the correction terms obtained from the computed equivalent mutual inductances. Simulations and experiments demonstrate that torque estimation errors are remarkably reduced by capturing and compensating for the inherent cross-coupling effects and parameter variations adaptively, using the proposed algorithm

Adaptive Torque Estimation for an IPMSM with Cross-Coupling and Parameter Variations

This paper presents a new adaptive torque estimation algorithm for an interior permanent magnet synchronous motor (IPMSM) with parameter variations and cross-coupling between d- and q-axis dynamics. All cross-coupled, time-varying, or uncertain terms that are not part of the nominal flux equations are included in two equivalent mutual inductances, which are described using the equivalent d- and q-axis back electromotive forces (EMFs). The proposed algorithm estimates the equivalent d- and q-axis back EMFs in a recursive and stability-guaranteed manner, in order to compute the equivalent mutual inductances between the d- and q-axes. Then, it provides a more accurate and adaptive torque equation by adding the correction terms obtained from the computed equivalent mutual inductances. Simulations and experiments demonstrate that torque estimation errors are remarkably reduced by capturing and compensating for the inherent cross-coupling effects and parameter variations adaptively, using the proposed algorithm

Additional file 1: of Incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer

Table S1. Preoperative laboratory values of participants, Table S2. Preoperative psychiatric variables of participants, Table S3. Correlations among DRS scores and other continuous variables, Table S4. Univariate logistic regression analysis to examine risk factors as continuous variables of subsyndromal delirium, Table S5. Multivariate logistic regression analysis to determine the independent risk factors as continuous variables of postoperative subsyndromal delirium, Figure S1. Histogram of pre-op DRS and post-op DRS. (DOCX 44 kb

Trajectory of severity of postoperative delirium symptoms and its prospective association with cognitive function in patients with gastric cancer: results from a prospective observational study

Purpose: Delirium is a common neurocognitive complication in cancer. Despite this, the studies examining the trajectory of the severity of delirium symptoms and its impact on health outcome in gastric cancer is rather limited. This study examined the trajectory of delirium symptom severity (DSS) following resection surgery for gastric cancer and its prospective association with cognitive function. Methods: A three-wave prospective observational study was conducted with 242 gastric cancer patients admitted for resection surgery at a teaching hospital in South Korea from May 2016 to November 2017. DSS was assessed by the clinical staff before and 1, 2, 3, and 7 days after surgery using the Delirium Rating Scale-Revised-98. A survey including the Functional Assessment of Cancer Therapy-Cognitive Scale (FACT-Cog) and Mini-Mental State Examination (MMSE) was administered before surgery (T0), 7 days after (T1), and 3 to 6 months after surgery (T2). Results: Out of 242 participants, 48.8% (118) completed the survey at all three time points, 43.4% (105) did so for two time points, and 7.9% (19) for one time point. No cases of full delirium were observed over four postoperative time points. Latent growth curve modeling analyses indicated that DSS declined over 3 days after surgery. Age and anesthesia time were positively associated with the initial level of DSS. A medication history for memory complaints was related to a slower recovery from delirium symptoms. While the use of propofol as an anesthetic agent was associated with lower initial DSS, it predicted a slower recovery from DSS. A higher initial DSS predicted a lower T1 MMSE score. Conclusions: Severity of postoperative delirium symptoms predicts a short-term and objective cognitive function post-surgery. Monitoring and timely treatment of postoperative delirium symptoms is needed to diminish cognitive consequences in gastric cancer patients