Generalized Multi-kernel Maximum Correntropy Kalman Filter for Disturbance Estimation

Disturbance observers have been attracting continuing research efforts and are widely used in many applications. Among them, the Kalman filter-based disturbance observer is an attractive one since it estimates both the state and the disturbance simultaneously, and is optimal for a linear system with Gaussian noises. Unfortunately, The noise in the disturbance channel typically exhibits a heavy-tailed distribution because the nominal disturbance dynamics usually do not align with the practical ones. To handle this issue, we propose a generalized multi-kernel maximum correntropy Kalman filter for disturbance estimation, which is less conservative by adopting different kernel bandwidths for different channels and exhibits excellent performance both with and without external disturbance. The convergence of the fixed point iteration and the complexity of the proposed algorithm are given. Simulations on a robotic manipulator reveal that the proposed algorithm is very efficient in disturbance estimation with moderate algorithm complexity.Comment: in IEEE Transactions on Automatic Control (2023

Evaluation of the effectiveness of EFL online teaching during the COVID-19 pandemic

Online teaching has been massively conducted during the novel coronavirus period all over the world. How to evaluate online teaching has been increasingly researched recently. This study looked at how English as a foreign language (EFL) teaching was delivered online by university teachers during the COVID-19 pandemic. We investigated university teachers and students’ perception of effective EFL online teaching and learning based on several evaluation modes in using technology in education. Data were collected using questionnaires and interviews from teachers and students in a variety of provinces in Mainland China. The results showed that various methods were used to deliver online EFL courses and these approaches are found to correlate with each other. Teachers and students provided positive comments on online teaching and were satisfied with their online teaching and learning. Participants also noted effective ways in online EFL teaching. The findings indicated that when teachers have more training, more skills, and more confidence, they could deliver more effective online teaching and learning. </jats:p

Hierarchical Pt-In Nanowires for Efficient Methanol Oxidation Electrocatalysis

Direct methanol fuel cells (DMFC) have attracted increasing research interest recently; however, their output performance is severely hindered by the sluggish kinetics of the methanol oxidation reaction (MOR) at the anode. Herein, unique hierarchical Pt-In NWs with uneven surface and abundant high-index facets are developed as efficient MOR electrocatalysts in acidic electrolytes. The developed hierarchical Pt89In11 NWs exhibit high MOR mass activity and specific activity of 1.42 A mgPt&minus;1 and 6.2 mA cm&minus;2, which are 5.2 and 14.4 times those of Pt/C, respectively, outperforming most of the reported MORs. In chronoamperometry tests, the hierarchical Pt89In11 NWs demonstrate a longer half-life time than Pt/C, suggesting the better CO tolerance of Pt89In11 NWs. After stability, the MOR activity can be recovered by cycling. XPS, CV measurement and CO stripping voltammetry measurements demonstrate that the outstanding catalytic activity may be attributed to the facile removal of CO due to the presence of In site-adsorbing hydroxyl species

Hierarchical Pt-In Nanowires for Efficient Methanol Oxidation Electrocatalysis

Direct methanol fuel cells (DMFC) have attracted increasing research interest recently; however, their output performance is severely hindered by the sluggish kinetics of the methanol oxidation reaction (MOR) at the anode. Herein, unique hierarchical Pt-In NWs with uneven surface and abundant high-index facets are developed as efficient MOR electrocatalysts in acidic electrolytes. The developed hierarchical Pt89In11 NWs exhibit high MOR mass activity and specific activity of 1.42 A mgPt−1 and 6.2 mA cm−2, which are 5.2 and 14.4 times those of Pt/C, respectively, outperforming most of the reported MORs. In chronoamperometry tests, the hierarchical Pt89In11 NWs demonstrate a longer half-life time than Pt/C, suggesting the better CO tolerance of Pt89In11 NWs. After stability, the MOR activity can be recovered by cycling. XPS, CV measurement and CO stripping voltammetry measurements demonstrate that the outstanding catalytic activity may be attributed to the facile removal of CO due to the presence of In site-adsorbing hydroxyl species

BMELTT: Blending MOOCs for English Language Teacher Training

Teachers’ beliefs exert a strong influence on their practice. Therefore it is essential that students undertaking teacher education develop an ability to critically assess their own beliefs in relation to practice. The BMELTT (Blending MOOCs for English Language Teacher Training) project explores how the integration of an existing MOOC (Massive Open Online Course) into ELT programmes at both undergraduate and postgraduate level, can impact on students’ beliefs, while at the same time providing them with the opportunity to engage in reflection with a global community of practice. The participants were students on ELT programmes in the UK, the Netherlands and China, some were experienced teachers and some were new to teacher education. BMELTT involved reflecting on ELT themes in three ways: face-to-face in class; through a Virtual Exchange (VE) with the project partners; and with all the participants on the MOOC (around 40,000). To the authors’ knowledge, there are no other research studies of this nature available, where a MOOC blend is used in conjunction with a VE to support the reflection on professional development in ELT. Another distinctive feature of BMELTT is that the action research cycle reported here was driven by an ‘expert student’, which enabled staff to see their practice from a novel perspective.The results illustrate that BMELTT stimulated a reflection on what it means to be an autonomous learner and an autonomous teacher in the digital age. It is hoped that these results can provide the ELT community with an innovative model of professional development

B-MELTT: Blending MOOCs for English language teacher training

Teachers’ beliefs exert a strong influence on their practice. Therefore it is essential that students undertaking teacher education develop an ability to critically assess their own beliefs in relation to practice. The BMELTT (Blending MOOCs for English Language Teacher Training) project explores how the integration of an existing MOOC (Massive Open Online Course) into ELT programmes at both undergraduate and postgraduate level, can impact on students’ beliefs, while at the same time providing them with the opportunity to engage in reflection with a global community of practice. The participants were students on ELT programmes in the UK, the Netherlands and China, some were experienced teachers and some were new to teacher education. BMELTT involved reflecting on ELT themes in three ways: face-to-face in class; through a Virtual Exchange (VE) with the project partners; and with all the participants on the MOOC (around 40,000). To the authors’ knowledge, there are no other research studies of this nature available, where a MOOC blend is used in conjunction with a VE to support the reflection on professional development in ELT. Another distinctive feature of BMELTT is that the action research cycle reported here was driven by an ‘expert student’, which enabled staff to see their practice from a novel perspective.The results illustrate that BMELTT stimulated a reflection on what it means to be an autonomous learner and an autonomous teacher in the digital age. It is hoped that these results can provide the ELT community with an innovative model of professional development