Backstepping Based Adaptive Control of Magnetic Levitation System

Abstract. In view of parameter uncertainty in the magnetic levitation system, the adaptive controller design problem is investigated for the system. Nonlinear adaptive controller based on backstepping is proposed for the design of the actual system with parameter uncertainty. The controller can estimate the uncertainty parameter online so as to improve control accuracy. Theoretical analysis shows that the closed-loop system is stable regardless of parameter uncertainty. Simulation results demonstrate the effectiveness of the presented method

Ensemble Feature Selection Method with Fast Transfer Model

Compared with the traditional ensemble feature selection methods, the recently-developed ensemble feature selection with block-regularized [m×2] cross-validation (EFSBCV) not only has a variance of the estimator smaller than that of random [m×2] cross-validation, but also enhances the selection probability of important features and reduces the selection probability of noise features. However, the adopted linear regression model without the use of the bias term in EFSBCV may easily lead to underfitting. Moreover, EFSBCV does not consider the importance of each feature subset. Aiming at these two problems, an ensemble feature selection method called EFSFT (ensemble feature selection method using fast transfer model) is proposed in this paper. The basic idea is that the base feature selector in EFSBCV adopts the fast transfer model in this paper, so as to introduce the bias term. EFSFT transfers 2m subsets of features as the source knowledge, and then recalculates the weight of each feature subset, and the linear model fitting ability with the addition of bias terms is better. The results on real datasets show that compared with EFSBCV, the average FP value by EFSFT reduces up to 58%, proving that EFSFT has more advantages in removing noise features. In contrast to least-squares support vector machine (LSSVM), the average TP value by EFSFT increases up to 5%, which clearly indicates the superiority of EFSFT over LSSVM in choosing important features

Coupling sensor to enzyme in the voltage sensing phosphatase.

Voltage-sensing phosphatases (VSPs) dephosphorylate phosphoinositide (PIP) signaling lipids in response to membrane depolarization. VSPs possess an S4-containing voltage sensor domain (VSD), resembling that of voltage-gated cation channels, and a lipid phosphatase domain (PD). The mechanism by which voltage turns on enzyme activity is unclear. Structural analysis and modeling suggest several sites of VSD-PD interaction that could couple voltage sensing to catalysis. Voltage clamp fluorometry reveals voltage-driven rearrangements in three sites implicated earlier in enzyme activation-the VSD-PD linker, gating loop and R loop-as well as the N-terminal domain, which has not yet been explored. N-terminus mutations perturb both rearrangements in the other segments and enzyme activity. Our results provide a model for a dynamic assembly by which S4 controls the catalytic site

Isolation of Thiobacillus spp. and its application in the removal of heavy metals from activated sludge

Two strains of Thiobacillus isolated from native excess activated sludge were identified as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans by 16S rRNA gene sequencing and physiological-biochemical characteristics. Single and mixed cultures of the strains were used to carry out bioleaching for 9 days in order to remove heavy metals from activated sludge. The changes in pH, oxidation-reduction potential, and contents of heavy metals were measured. The results show that the bioleaching effect of the mixed culture was best in all runs, and that the final removals of As, Cr, Cu, Ni, and Zn were 96.09, 93.47, 98.32, 97.88, and 98.60%, respectively, whereas the removals of Cd and Pb decreased rapidly after six days. In addition, we demonstrate for the first time that bioleaching can reduce the pathogenicity of sludge by detecting fecal coliforms before and after bioleaching in order to ensure that the sludge was suitable for agricultural land application.Key words: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, excess activated sludge, removing heavy metals, sludge pathogenicity

Transcriptome profiling of Saccharomyces cerevisiae mutants lacking C2H2 zinc finger proteins

<p>Abstract</p> <p>Background</p> <p>The budding yeast <it>Saccharomyces cerevisiae</it> is a eukaryotic organism with extensive genetic redundancy. Large-scale gene deletion analysis has shown that over 80% of the ~6200 predicted genes are nonessential and that the functions of 30% of all ORFs remain unclassified, implying that yeast cells can tolerate deletion of a substantial number of individual genes. For example, a class of zinc finger proteins containing C2H2 zinc fingers in tandem arrays of two or three is predicted to be transcription factors; however, seven of the thirty-one predicted genes of this class are nonessential, and their functions are poorly understood. In this study we completed a transcriptomic profiling of three mutants lacking C2H2 zinc finger proteins, <it>ypr013cΔ,</it><it>ypr015cΔ</it> and <it>ypr013cΔypr015cΔ</it>.</p> <p>Results</p> <p>Gene expression patterns were remarkably different between wild type and the mutants. The results indicate altered expression of 79 genes in<it> ypr013</it>cΔ, 185 genes in <it>ypr015</it>cΔ and 426 genes in the double mutant when compared with that of the wild type strain. More than 80% of the alterations in the double mutants were not observed in either one of the single deletion mutants. Functional categorization based on Munich Information Center for Protein Sequences (MIPS) revealed up-regulation of genes related to transcription and down-regulation of genes involving cell rescue and defense, suggesting a decreased response to stress conditions. Genes related to cell cycle and DNA processing whose expression was affected by single or double deletions were also identified.</p> <p>Conclusion</p> <p>Our results suggest that microarray analysis can define the biological roles of zinc finger proteins with unknown functions and identify target genes that are regulated by these putative transcriptional factors. These findings also suggest that both YPR013C and YPR015C have biological processes in common, in addition to their own regulatory pathways.</p

A CREATIVE PARTNERSHIP AND AN INNOVATIVE AND EFFECTIVE MULTIMEDIA ENGLISH LANGUAGE LEARNING AND TEACHING WEBSITE

"in2english" as an innovative and effective multimedia English language learning and teaching website came about through a creative partnership between the British Council (BC), the British Broadcasting Corporation (BBC), China Central Radio and Television University (CCRTVU) and CRTVU-Online Distance Educational Technology Limited (CRTVU-Online). As a cooperative endeavor it combines British expertise in English teaching and development of online materials with CCRTVU's knowledge and experience of the English learning environment in China as well as expertise in ICT and development of online materials. At its inception many of the website's features were innovative and cutting edge. The free website goes beyond text and makes extensive use of multimedia. Since its launch on 5th November 2002 the website has welcomed nearly 10 million unique visitors, visited 18 million times, from its target audience of business people, English teachers, young professionals and their children. During five years of development "in2english" has evolved into a highly interactive community. "myin2english", a personalized feature, helps foster the learners' participation and ventures into the world of mobile learning highlight its continuing commitment to innovation. However, it is also a time to reflect on the lessons learned about Chinese learners' attitude to online learning. A retrospective and critical approach is needed to see how far we have come, how creative and innovative we are now and how we should proceed in the future