Modeling and adaptive tracking for stochastic nonholonomic constrained mechanical systems

This paper is devoted to the problem of modeling and trajectory tracking for stochastic nonholonomic dynamic systems in the presence of unknown parameters. Prior to tracking controller design, the rigorous derivation of stochastic nonholonomic dynamic model is given. By reasonably introducing so-called internal state vector, a reduced dynamic model, which is suitable for control design, is proposed. Based on the backstepping technique in vector form, an adaptive tracking controller is then derived, guaranteeing that the mean square of the tracking error converges to an arbitrarily small neighborhood of zero by tuning design parameters. The efficiency of the controller is demonstrated by a mechanics system: a vertical mobile wheel in random vibration environment

GROUND REACTON FORCE OF TABLE TENNIS PLAYERS WHEN USING FOREHAND ATTACK AND LOOP DRIVE TECHNIQUE

The subjects were 10 excellent ping-pong players in China. The table tennis techniques of the forehand attack and forehand loop drive were tested, using the measurement methods of the KISTLER force-plate system. The results showed that the biggest GRF of the attack technique in vertical direction was higher than the loop drive technique, and the biggest GRF of the attack technique in left-right direction and the fore-aft direction were mostly lower than the loop drive technique

Aqua­(benzamidato-κN)bis­[3,5-difluoro-2-(pyridin-2-yl)phenyl-κC 1]iridium(III) methanol monosolvate

In the title compound, [Ir(C11H6F2N)2(C7H6NO)(H2O)]·CH3OH, the IrIII ion adopts an octa­hedral geometry, and is coordinated by two 3,5-difluoro-2-(pyridin-2-yl)phenyl ligands, one mol­ecule of water and one benzamidate anion. The two 2-(4,6-difluoro­phen­yl)pyridyl ligands are arranged in a cis-C,C′ and trans-N,N′ fashion. Additionally, there is a bystanding methanol mol­ecule outside the coordination sphere of the IrIII ion. In the crystal, mol­ecules of the title compound are linked by O—H⋯O and O—H⋯N hydrogen bonds. One F atom of each ligand is equally disordered over two sites. The C atom of the solvent molecule is likewise disordered over two sites in a 0.589 (11):0.411 (11) ratio

A Detection Method for Phishing Web Page Using DOM-Based Doc2Vec Model

Detecting phishing web pages is a challenging task. The existing detection method for phishing web page based on DOM (Document Object Model) is mainly aiming at obtaining structural characteristics but ignores the overall representation of web pages and the semantic information that HTML tags may have. This paper regards DOMs as a natural language with Doc2Vec model and learns the structural semantics automatically to detect phishing web pages. Firstly, the DOM structure of the obtained web page is parsed to construct the DOM tree, then the Doc2Vec model is used to vectorize the DOM tree, and to measure the semantic similarity in web pages by the distance between different DOM vectors. Finally, the hierarchical clustering method is used to implement clustering of web pages. Experiments show that the method proposed in the paper achieves higher recall and precision for phishing classification, compared to DOM-based structural clustering method and TF-IDF-based semantic clustering method. The result shows that using Paragraph Vector is effective on DOM in a linguistic approach

Application of Chemical Transport Models to Study Global and Regional Air Quality and Human Health

Climate change and air quality are interrelated issues. Policies to mitigate greenhouse gas (GHG) emissions will not only slow climate change, but can also bring co-benefits of improved air quality and avoided mortality. Here I examine the co-benefits of global and regional GHG mitigation on US air quality and human health in 2050 at fine resolution, by dynamically downscaling a previous global study on the co-benefits of global GHG mitigation. The US average total co-benefits of global GHG mitigation in RCP4.5 are 0.47 µg m-3 for annual average PM2.5 and 3.55 ppb for ozone-season maximum daily 8-hour average O3, avoiding 24500 (90% confidence interval, 17800-31100) all-cause deaths related to PM2.5, and 12200 (5400-18900) respiratory deaths for O3. Reductions in co-emitted air pollutants dominate the total co-benefits, much higher than those via slowing climate change. GHG mitigation from foreign countries avoids 3700 (2700-4700) PM2.5-related deaths (15% of the total), and contributes more to the US O3 reduction than domestic GHG mitigation, avoiding 7600 O3-related deaths (3400-11900, 62%), highlighting the importance of global methane reductions and intercontinental air pollutant transport. GHG mitigation in the US residential sector brings the largest co-benefits for PM2.5-related deaths (21% of the total domestic co-benefits), and industry for O3 (17%). The US gains significantly greater co-benefits by coordinating GHG reductions with foreign countries. Previous studies estimating co-benefits locally or regionally may greatly underestimate the full co-benefits of coordinated global actions. I also investigated the causes of changes in the global tropospheric ozone burden (BO3) from 1980 to 2010 using a global atmospheric model, isolating the effect of the emissions shifting southwards from emission increases in developing countries and decreases in developed countries. The global emission spatial distribution change accounts for more than half of the total BO3 change (28.12 Tg), even larger than the combined effects of the global emission magnitude change and global methane change. This highlights the dominant role of emissions from the tropics, especially over South and Southeast Asia, for the tropospheric O3 burden, and suggests that BO3 might continue to increase as emissions shift south, even if global emissions remain unchanged or even decrease.Doctor of Philosoph

Thinking on the Reform of Experimental Teaching Scene Based on the Integration of Industry and Finance

The technological transformation of big data, artificial intelligence, mobile internet and cloud computing have promoted the transformation of enterprise business model, and the experimental teaching in colleges and universities also needs to be reformed. Based on the business integration experiment teaching, this paper puts forward some thoughts on how to reform the experiment teaching from the aspects of teaching scene design, teaching scene selection, teaching scene interest, teaching method design and so on; It is proposed that the business integration experiment should pay attention to the students' experience, enhance the enthusiasm and initiative of the students in the experimental teaching, strengthen the training of the students' data thinking ability, and cultivate the students' data analysis ability under the integration of industry and finance

Cross-Scale Cost Aggregation for Stereo Matching

Human beings process stereoscopic correspondence across multiple scales. However, this bio-inspiration is ignored by state-of-the-art cost aggregation methods for dense stereo correspondence. In this paper, a generic cross-scale cost aggregation framework is proposed to allow multi-scale interaction in cost aggregation. We firstly reformulate cost aggregation from a unified optimization perspective and show that different cost aggregation methods essentially differ in the choices of similarity kernels. Then, an inter-scale regularizer is introduced into optimization and solving this new optimization problem leads to the proposed framework. Since the regularization term is independent of the similarity kernel, various cost aggregation methods can be integrated into the proposed general framework. We show that the cross-scale framework is important as it effectively and efficiently expands state-of-the-art cost aggregation methods and leads to significant improvements, when evaluated on Middlebury, KITTI and New Tsukuba datasets.Comment: To Appear in 2013 IEEE Conference on Computer Vision and Pattern Recognition (CVPR). 2014 (poster, 29.88%

Effects of Global Warming on Work-Rest Routines for Crop Workers in Appalachia

Background: Workers in outdoor occupations are expected to be at high risk of increased morbidity and mortality, and diminished productivity, as a result of global warming in the 21st century. A previous modelling study of geographic variations in heat-related mortality risk in projected U.S. populations mid-century showed the states of Tennessee, Kentucky and North Carolina to be highly vulnerable. Methods: Under both the RCP4.5 and RCP8.5 emissions scenarios of IPCC AR5, we evaluate the effect of future warming on estimated Wet Bulb Globe Thermometer (WBGT) temperatures using model-simulated future climate variables that were dynamically downscaled by a regional meteorology model for years 2049-2052. Select Appalachian counties in the three states that are presently dependent upon agricultural crop production are the focus of this analysis. Results: Using predicted WBGT temperatures, together with estimated work loads for hand harvesting of crops, alterations in work-rest routines under heat stress prevention guidelines are presented. Conclusions: Assumptions needed to translate these altered work-rest routines into measures of productivity and economic loss are discussed. Issues in extending the modelling to heat-related morbidity and mortality in outdoor worker populations are considered in terms of data gaps and major sources of uncertainty

Examining Individuals’ Utilization of SPOC: Extending the Task-Technology Fit Model with Online and Offline Perspective

Small Private Online Course (SPOC) platform enables individuals to carry out their learning tasks both online and offline. In order to understand individuals’ utilization of SPOC, this study develops a research model to examine the joint influences of three types of perceived fit manifested in perceived technology-task fit (TTF), perceived individual-technology fit (ITF) and perceived online-offline fit (OOF). A survey was conducted in a famous university of China and 371 data were collected from students who selected courses on the SPOC platform. Structural equation modelling method was used to examine the research model. The empirical results suggest that ITF is the most significant antecedent of individual performance expectancy, followed by OOF and TTF. Moreover, individual performance expectancy has a positive influence on user satisfaction and individuals’ continuance intention in the SPOC platform. A post-hoc analysis further indicates that student’s GPA positively moderates the relationship between online participation behavior and course performance. This study extends the traditional perceived fit framework by introducing perceived online-offline fit, and uncovers the antecedents and outcomes of individuals’ utilization in the emerging research context of SPOC