A Quasi-ARX Model for Multivariable Decoupling Control of Nonlinear MIMO System

This paper proposes a multiinput and multioutput (MIMO) quasi-autoregressive eXogenous (ARX) model and a multivariable-decoupling proportional integral differential (PID) controller for MIMO nonlinear systems based on the proposed model. The proposed MIMO quasi-ARX model improves the performance of ordinary quasi-ARX model. The proposed controller consists of a traditional PID controller with a decoupling compensator and a feed-forward compensator for the nonlinear dynamics based on the MIMO quasi-ARX model. Then an adaptive control algorithm is presented using the MIMO quasi-ARX radial basis function network (RBFN) prediction model and some stability analysis of control system is shown. Simulation results show the effectiveness of the proposed control method

How does internal and external CSR affect employees’ work engagement? Exploring multiple mediation mechanisms and boundary conditions

We investigate the different mechanisms concerning how employees’ perceptions of external and internal corporate social responsibility (CSR) serve to influence employees’ work engagement. By combining social exchange theory and social identity theory, we implement and examine an integrated moderated mediation framework in which employees’ value orientations (e.g., collectivism or individualism) impact the mediating mechanism between their perceived external and internal CSR, organizational pride and perceived organizational support (POS), and work engagement. This work fills a research gap to examine the indirect relationship between employees’ perceptions of external and internal CSR and work engagement. Using two periods of survey data from 250 working employees in China, we find that employees’ perceptions of external CSR positively influence work engagement via organizational pride. The value of collectivism strengthens the direct effect of employees’ perceptions of external CSR on work engagement, and the indirect effect of employees’ perceptions of external CSR on work engagement via organizational pride. Moreover, employees’ perceptions of internal CSR positively influence work engagement via POS. The value of individualism strengthens the direct effect of employees’ perceptions of internal CSR on work engagement, and the indirect effect of employees’ perceptions of internal CSR on work engagement via POS. The results contribute to both theory and practice

Nonlinear System Identification Using Quasi-ARX RBFN Models with a Parameter-Classified Scheme

Quasi-linear autoregressive with exogenous inputs (Quasi-ARX) models have received considerable attention for their usefulness in nonlinear system identification and control. In this paper, identification methods of quasi-ARX type models are reviewed and categorized in three main groups, and a two-step learning approach is proposed as an extension of the parameter-classified methods to identify the quasi-ARX radial basis function network (RBFN) model. Firstly, a clustering method is utilized to provide statistical properties of the dataset for determining the parameters nonlinear to the model, which are interpreted meaningfully in the sense of interpolation parameters of a local linear model. Secondly, support vector regression is used to estimate the parameters linear to the model; meanwhile, an explicit kernel mapping is given in terms of the nonlinear parameter identification procedure, in which the model is transformed from the nonlinear-in-nature to the linear-in-parameter. Numerical and real cases are carried out finally to demonstrate the effectiveness and generalization ability of the proposed method

Calpain inhibitor MDL-28170 reduces the functional and structural deterioration of corpus callosum following fluid percussion injury

It is known that calpain activation is involved in human traumatic brain injury (TBI) and that calpain inhibition can have neuroprotective effects on both gray matter and white matter injury of TBI models. However, the role of calpain activation in the corpus callosum remains unclear and requires elucidation given its potential clinical relevance. We evaluated the neuroprotective effects of calpain inhibitor MDL-28170 on corpus callosum function and structural destruction using a fluid percussion injury (FPI) model. The therapeutic time window for a single administration of MDL-28170 was up to 4 h post injury in protecting the corpus callosum structural integrity, and up to 30 min in protecting the axonal function evaluated 1 day following injury. When given 30 min prior injury, MDL-28170 showed neuroprotective effects that lasted up to 7 days. However, 30 min post injury administration of the drug afforded neuroprotection only up to 3 days. In contrast, two additional reinforcement injections at 24 and 48 h in addition to 30 min post FPI significantly protected both axonal function and structural integrity that lasted 14 days following FPI. Our data indicated that calpain inhibitor MDL-28170 is an effective neuroprotectant for axonal injury in corpus callosum following FPI with a therapeutic time window up to 4 hours. Although delayed treatment (2 or 4 h post FPI) was effective in protecting the axonal structure, the axons saved may not be as functional as normal fibers. Multiple drug administrations may be necessary for achieving a persisting effectiveness of this compound. © Mary Ann Liebert, Inc