The Effects of an English Public Speaking Course on Critical Thinking Dispositions of Chinese EFL University Students

( Mengxue Zhang ),( Na-young Kim ) 글로벌영어교육학회 2021 Studies in English education Vol.26 No.4

This study aims to explore the effects of an English public speaking (EPS) course on Chinese EFL university students’ critical thinking dispositions (CTD) according to their proficiency levels. 115 freshmen from a university in China participated in this current study and they were randomly divided into one experimental group (n = 55) and one control group (n = 60). According to the scores of TOEIC listening, the participants were grouped into three proficiency levels - low-level, intermediate-level and high-level. During the sixteen-week treatment, the experimental group was required to take the EPS course while the control group took a traditional English speaking course. To confirm the effects of the EPS course, pre- and post-tests regarding the CTD were conducted. The results of the independent t-tests revealed that the EPS course had positive effects on enhancing the CTD of Chinese EFL students regardless of their English proficiency levels. The results of the one-way ANOVA demonstrated that students with higher proficiency levels improved more significantly regarding all the dimensions of CTD. Based on the results, several pedagogical implications are made.

The impact of artificial discrete simulation of wind field on vehicle running performance

Mengxue Wu,Yongle Li,Ning Chen 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

To investigate the effects of “sudden change” of wind fluctuations on vehicle runningperformance, which is caused by the artificial discrete simulation of wind field, a three-dimensional vehiclemodel is set up with multi-body dynamics theory and the vehicle dynamic responses in crosswind conditionsare obtained in time domain. Based on Hilbert Huang Transform, the effects of simulation separations ontime-frequency characteristics of wind field are discussed. In addition, the probability density distribution of“sudden change” of wind fluctuations is displayed, addressing the effects of simulation separation, meanwind speed and vehicle speed on the “sudden change” of wind fluctuations. The “sudden change” of vehicledynamic responses, which is due to the discontinuity of wind fluctuations on moving vehicle, is alsoanalyzed. With Principal Component Analysis, the comprehensive evaluation of vehicle runningperformance in crosswind conditions at different simulation separations of wind field is investigated. Theresults demonstrate that the artificial discrete simulation of wind field often causes “sudden change” in thewind fluctuations and the corresponding vehicle dynamic responses are noticeably affected. It provides atheoretical foundation for the choice of a suitable simulation separation of wind field in engineeringapplication.

A Data Fusion Algorithm of GNSS/INS/ Odometer Integrated System In Consideration of Total Odometer Errors

Mengxue. Mu,Long. Zhao 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

The low cost GNSS/INS integrated system applied in the land vehicle can benefit from the information fusion of odometer and motion aided constraints. However, the performance of the fusion system is affected by four key issues. Firstly, odometer scale factor is not a constant value and differs with the change of temperature, tire pressure and vehicle load. Secondly, the odometer measures velocity in the vehicle body frame (VBF) rather than the inertial sensor frame, whereas misalignment between the inertial measurement unit (IMU) and the VBF generally exists. Thirdly, the IMU origin doesn’t coincide with the odometer origin, lever arm influences the position accuracy. Fourthly, poor road condition may make the wheel spin or slide, and eventually leads to odometer failure. To solve aforementioned problems, this paper attempts to provide a scale factor and misalignment estimation method, a lever arm compensation (LAC) approach, and an odometer fault detection and isolation (FDI) indicator according to the odometer position error propagation equation. In addition, a two-cascaded Kalman filter is designed based on the context awareness to fuse all data information. Simulation experiment demonstrates the effectiveness of the scale factor and misalignment calibration algorithm, lever arm compensation approach and fault detection indicator. Moreover, the processed fusion system can significantly improve the positioning accuracy in GNSS-hostile environment.

Impacts of wind shielding effects of bridge tower on railway vehicle running performance

Wu, Mengxue,Li, Yongle,Zhang, Wei Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.1

When railway vehicles run by towers of long span bridges, the railway vehicles might experience a sudden load-off and load-on phenomenon in crosswind conditions. To ensure the running safety of the railway vehicles and the running comfort of the passengers, some studies were carried out to investigate the impacts of sudden changes of aerodynamic loads on moving railway vehicles. In the present study, the aerodynamic coefficients which were measured in wind tunnel tests using a moving train model are converted into the aerodynamic coefficients in the actual scale. The three-component aerodynamic loads are calculated based on the aerodynamic coefficients with consideration of the vehicle movement. A three-dimensional railway vehicle model is set up using the multibody dynamic theory, and the aerodynamic loads are treated as the inputs of excitation varied with time for kinetic simulations of the railway vehicle. Thus the dynamic responses of the railway vehicle passing by the bridge tower can be obtained from the kinetic simulations in the time domain. The effects of the mean wind speeds and the rail track positions on the running performance of the railway vehicle are discussed. The three-component aerodynamic loads on the railway vehicle are found to experience significant sudden changes when the vehicle passes by the bridge tower. Correspondingly, such sudden changes of aerodynamic loads have a large impact on the dynamic performance of the running railway vehicle. The dynamic responses of the railway vehicle have great fluctuations and significant sudden changes, which is adverse to the running safety and comfort of the railway vehicle passing by the bridge tower in crosswind conditions.

The impact of artificial discrete simulation of wind field on vehicle running performance

Wu, Mengxue,Li, Yongle,Chen, Ning Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

To investigate the effects of "sudden change" of wind fluctuations on vehicle running performance, which is caused by the artificial discrete simulation of wind field, a three-dimensional vehicle model is set up with multi-body dynamics theory and the vehicle dynamic responses in crosswind conditions are obtained in time domain. Based on Hilbert Huang Transform, the effects of simulation separations on time-frequency characteristics of wind field are discussed. In addition, the probability density distribution of "sudden change" of wind fluctuations is displayed, addressing the effects of simulation separation, mean wind speed and vehicle speed on the "sudden change" of wind fluctuations. The "sudden change" of vehicle dynamic responses, which is due to the discontinuity of wind fluctuations on moving vehicle, is also analyzed. With Principal Component Analysis, the comprehensive evaluation of vehicle running performance in crosswind conditions at different simulation separations of wind field is investigated. The results demonstrate that the artificial discrete simulation of wind field often causes "sudden change" in the wind fluctuations and the corresponding vehicle dynamic responses are noticeably affected. It provides a theoretical foundation for the choice of a suitable simulation separation of wind field in engineering application.

Kindness and Hospitality in Dickens’s Great Expectations : Focusing on Joe and Biddy

Ji Mengxue 새한영어영문학회 2022 새한영어영문학회 학술발표회 논문집 Vol.2022 No.5

Wind-tunnel study of wake galloping of parallel cables on cable-stayed bridges and its suppression

Yongle Li,Mengxue Wu,Xinzhong Chen,Tao Wang,Haili Liao 한국풍공학회 2013 Wind and Structures, An International Journal (WAS Vol.16 No.3

Flexible stay cables on cable-stayed bridges are three-dimensional. They sag and flex in the complex wind environment, which is a different situation to ideal rigid cylinders in two-dimensional wind flow. Aerodynamic interference and the response characteristics of wake galloping of full-scale parallel cables are potentially different due to three-dimensional flows around cables. This study presents a comprehensive wind tunnel investigation of wake galloping of parallel stay cables using three-dimensional aeroelastic cable models. The wind tunnel study focuses on the large spacing instability range, addressing the effects of cable separation, wind yaw angle, and wind angle of attack on wake galloping response. To investigate the effectiveness of vibration suppression measures, wind tunnel studies on the transversely connected cable systems for two types of connections (flexibility and rigidity) at two positions (mid-span and quarter-span) were also conducted. This experimental study provides useful insights for better understanding the characteristics of wake galloping that will help in establishing a guideline for the wind-resistant design of the cable system on cable-stayed bridges.

Reputation-Based Collusion Detection with Majority of Colluders

HUR, Junbeom,GUO, Mengxue,PARK, Younsoo,LEE, Chan-Gun,PARK, Ho-Hyun 'Institute of Electronics, Information and Communi 2016 IEICE transactions on information and systems Vol.99e.d No.7

<P>The reputation-based majority-voting approach is a promising solution for detecting malicious workers in a cloud system. However, this approach has a drawback in that it can detect malicious workers only when the number of colluders make up no more than half of all workers. In this paper, we simulate the behavior of a reputation-based method and mathematically analyze its accuracy. Through the analysis, we observe that, regardless of the number of colluders and their collusion probability, if the reputation value of a group is significantly different from those of other groups, it is a completely honest group. Based on the analysis result, we propose a new method for distinguishing honest workers from colluders even when the colluders make up the majority group. The proposed method constructs groups based on their reputations. A group with the significantly highest or lowest reputation value is considered a completely honest group. Otherwise, honest workers are mixed together with colluders in a group. The proposed method accurately identifies honest workers even in a mixed group by comparing each voting result one by one. The results of a security analysis and an experiment show that our method can identify honest workers much more accurately than a traditional reputation-based approach with little additional computational overhead.</P>

Wind-tunnel study of wake galloping of parallel cables on cable-stayed bridges and its suppression

Li, Yongle,Wu, Mengxue,Chen, Xinzhong,Wang, Tao,Liao, Haili Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.16 No.3

Flexible stay cables on cable-stayed bridges are three-dimensional. They sag and flex in the complex wind environment, which is a different situation to ideal rigid cylinders in two-dimensional wind flow. Aerodynamic interference and the response characteristics of wake galloping of full-scale parallel cables are potentially different due to three-dimensional flows around cables. This study presents a comprehensive wind tunnel investigation of wake galloping of parallel stay cables using three-dimensional aeroelastic cable models. The wind tunnel study focuses on the large spacing instability range, addressing the effects of cable separation, wind yaw angle, and wind angle of attack on wake galloping response. To investigate the effectiveness of vibration suppression measures, wind tunnel studies on the transversely connected cable systems for two types of connections (flexibility and rigidity) at two positions (mid-span and quarter-span) were also conducted. This experimental study provides useful insights for better understanding the characteristics of wake galloping that will help in establishing a guideline for the wind-resistant design of the cable system on cable-stayed bridges.

Rectifying resistance switching behaviors of SnO2 microsphere films modulated by top electrodes

Rongchun Yuan,Weiwei Xia,Mengxue Xu,Zhilei Miao,Shudong Wu,Xiuyun Zhang,Junhui He,Qiang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.3

Based on the bipolar resistive switching (RS) characteristics of SnO2 films, we have fabricated a new prototypical device with sandwiched structure of Metal/SnO2/fluorine-doped tin oxide (FTO). The SnO2 microspheres film was grown on FTO glass by template-free hydrothermal synthesis, which was evaporated with various commonly used electrodes such as aluminium (Al), silver (Ag), and gold (Au), respectively. Typical self-rectifying resistance switching behaviors were observed for the RS devices with Al and Au electrodes. However, no obvious rectifying resistance switching behavior was observed for the RS device with Ag electrode. Above results were interpreted by considering the different interface barriers between SnO2 and top metal electrodes. Our current studies pave the ways for modulating the self-rectifying resistance switching properties of resistive memory devices by choosing suitable metal electrodes.