A New Closed-loop Control Allocation Method with Application to Direct Force Control

Wendong Gai,Jie Liu,Jing Zhang,Yuxia Li 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3

A new closed-loop control allocation method is proposed to distribute the force and moment increment commands among multiple actuators at the same time. An innovative feedback configuration for the force and moment increment produced by the actuators deflections is added into the trajectory and attitude control loop, respectively. In addition, the trajectory and attitude controllers designed by nonlinear dynamic inversion are used to derive the desired force and moment increment commands. Then, the stability of the closed-loop system is guaranteed theoretically when the actuators are healthy and fail, where there is no a fault detection method to identify the failure. Finally, the proposed method is used to achieve direct force control for decoupling the attitude and flight trajectory in the longitudinal flight. The nonlinear simulation using Canard Rotor/Wing (CRW) aircraft longitudinal model in fixed-wing mode demonstrates that this method can achieve two direct force control modes: pitch pointing and direct lift, whether the actuators are healthy or fail.

Web-Platform Construction of Practical Sports English for College Athletes

( Wei Liu ),( Wendong Li ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

Purpose: Through the study of constructing a practical sports English web-platform, the researcher aims to improve college athletes` English level and teachers` teaching level which will further strengthen students English language proficiency to accommodate them to their future job and make their contribution to the country`s sports cause. Method: Literature review: look up the literature related to practical sports English web-platform construction to prepare for the research Expert interview: consult experts in sports and college English to learn the research path and research objects` various indicators Questionnaire: Sample survey sports major graduates, college English teachers and computer technicians to investigate graduates` needs of practical English in their job, English teachers` teaching content as well as web-platform`s design and implementation,etc. Mathematical statistics method: Use SPSS software to make statistical analysis of the returned questionnaire and scale Logical analysis method: search for practical English cases in the references of practical sports English, and then analyze, induce and summarize practical sports English content through concept, deduction and judgment, etc. Results: 1. All interviewed students can make use of the online resources through internet websites, such as English audio and visual materials, English movies and spoken English exercises, etc. 2. Some of the students interviewed have demonstrated low efficiency in using the learning resources on the web, which is attributed to their unfamiliarity with computers or internet and poor judging ability of the difficult level of the resources. Conclusions: 1. The website designers of the English learning resources should pay attention to both instruct and interest the learners and they should also grade the materials to different difficult levels. 2. English teachers should make quick response to students` questions and their problems in using the online resources which should be regularly updated to meet the students` needs. 3. It requires the joint efforts from schools, teachers and students to enable the learners to make extensive and efficient use of the English learning web platforms which have been proved to be an important approach in learning.

A Study of Chinese College Athletes` English Learning

( Wei Liu ),( Wendong Li ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

Background: As a special English learning group, Chinese college student athletes only account for a tiny percentage of the total English learners in China, but their number is still quite large. Their English education has its unique characteristics, different from the ones of regular students. Firstly, the majority of their time is spent in sports training and attending various matches with little time left for English study. Secondly, their English knowledge basis is weak, and learning methods are outdated and inefficient. Finally, the most important thing for the sports college students is the fact that with the increase of international matches, their international communication skills have determined whether they are able to integrate smoothly into international arena and also greatly affected their career future. Therefore, a research to understand and analyze Chinese college student athletes` English learning and further to put forward a proper learning strategy for them have vital practical significance to their English study. Purpose: This paper analyzes the problems Chinese college student athletes encounter in learning English and provides relevant approaches for improvement. Method: Literature review, interview, case-study Results: 1. Chinese college student athletes have two common paths of English learning . One is the routine English skills training in college English courses. And the other is through attending international matches and overseas life experience, which offer chances to improve their practical English proficiency. 2. The improvement of Chinese college student athletes` English level will greatly increase their interaction with overseas sports persons, agencies and spectators and promote related sports items` popularity. And the students will also be able to independently cope with everyday life and communications in and out of the sports arenas, adapting well to meet with the requirements of a more and globalized Chinese sports. Conclusions: 1. In terms of English learning modes, Chinese college student athletes should fully exploit the advantages of modern teaching resources by adopting online teaching tools such as learning on Weibo, Weixin and video teaching platforms like MOOC, along with other flexible approaches. 2. As for English study content, Chinese college student athletes should strengthen their sports spoken English and technical English expressions. Due to their widespread problem of an unsolid English language foundation, there are still unavoidable grammar mistakes. Therefore, a systematical English writing study should be suggested to prepare them for a better career prospect.

Translation Strategy of Sports Movie Titles

( Wei Liu ),( Wendong Li ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

Purpose: Sports movies are the films featuring stories about sports persons and activities. This type of movies have won great attention and popularity among all movies because of the uplifting spirits of passion and perseverance exemplified by the sports in the movies, as well as their satisfaction of human`s desires of self-transcendence and dream-fulfillment. Therefore, sports movies have been a hot topic since its first advent 100 years ago. As a special field of translation, movie titles translation into Chinese can convey a movie`s major messages to the audience which is a great help to facilitate audience`s understanding of the film. Methods: Literature review Expert interview Case study Logic analysis Results: 1. Sports movie titles translation is subject to the influence of the factors of box office and anesthetics. It can directly impact the movie makers in whether the filming investment can be rewarded to finance further more sports movies or not. The sports spirits demonstrated through the movies are usually positively inspiring and unyielding, and the protagonists` success is achieved through step-by-step hard work to become sports stars or champions. Audience can be both informed of the stories and inspired by the sports spirits through the translation of the movie titles. 2. There are three approaches in sports movie titles translation, i.e., literal translation, liberal translation and amplification translation. 3. There are some problems in the translation of sports movie titles, such as the practice of word-for-word translation of the original English titles failing to make a good combination with the movie`s plots and subject. Conclusion: Sports movie is an art of combining audio and visual faculties, their titles translation has direct influence to the audience`s understanding of the movies` subject. It is not only an art form but also a bridge between China and other countries in cultural exchanges and an important medium of cultural input and output. Translators should make intensive study and insightful analysis of the sports movies` story and subject and strive to realize both sports movies business value and educational functions by adept use of various translation methods and techniques. Meanwhile, translators should also learn western cultures and understand the cultural differences to work out a perfect translation by achieving a balance of "faithfulness, expressiveness and elegance".

Nonlinear Adaptive Backstepping with ESO for the Quadrotor Trajectory Tracking Control in the Multiple Disturbances

Jie Liu,Wendong Gai,Jing Zhang,Yuxia Li 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.11

In this paper, we present a nonlinear adaptive backstepping with extended state observer (ESO) trajectory tracking controller for a quadrotor unmanned aerial vehicle (UAV) subject to the multiple disturbances, which include the parametric uncertainties, actuator faults and external disturbance. First, a six-degrees of freedom quadrotor UAV model with the multiple disturbances function is built. Second, the adaptive backstepping controller is designed to track the desired trajectory command aim at internal disturbance. And the adaptive backstepping controller with ESO is designed to track the desired trajectory command aim at external disturbance. Third, the stability of the system is proved by the circle criterion. Finally, under different flight scenarios, simulation results are given to demonstrate the effectiveness of the proposed method.

Piperonyl butoxide synergizes the larvicidal activity of Origanum vulgare essential oil and its major constituents against the larvae of Aedes albopictus and Culex pipiens quinquefasciatus

Chen Junhui,Liu Yangqing,Ma Guangqiang,Yang Feiying,Zhan Zhigao,Guan Limei,Kuang Wendong,Wang Jinchang,Li Jianghuai,Han Fei,Jin Liang 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.1

Mosquitoes bite human beings and transmit many diseases, such as malaria, dengue fever, and Zika virus. Vector control of mosquitoes is an effective strategy for reducing the spread of disease. However, extensive use of in secticides (e.g. pyrethroids and organophosphorus) has caused resistance in mosquitoes, which weakens the effectiveness of mosquito control. Phytochemicals have been considered an alternative approach to mosquito control. Essential oil (EO) was obtained from the leaves and flowers of Origanum vulgare, and its synergistic activity with piperonyl butoxide (PBO) was tested against Aedes albopictus and Culex pipiens quinquefasciatus larvae. Thirty-seven compounds were identified, among which carvacrol and thymol were two major constitu ents (30.73 % and 18.81 %, respectively). O. vulgare EO had a significant toxic effect against fourth-stage larvae of Cx. p. quinquefasciatus and Ae. albopictus, with LC 50 values of 17.51 and 75.90 mg/L. Carvacrol and thymol also each appeared to be more effective against Cx. p. quinquefasciatus (LC 50 = 19.30 and 11.56 mg/L, respectively) than Ae. albopictus (LC 50 = 26.62 and 26.66 mg/L, respectively). PBO interacted synergistically with O. vulgare EO, carvacrol and thymol with 2.60–6.26 times as much of the active compound needed without PBO as against Cx. p. quinquefasciatus and Ae. albopictus larvae. Overall, our results contribute to the development of new natural mosquito insecticides.

Molecular dynamics study of H4TTP crystal morphology

Chen Jing,Li Jun,Li Yongxiang,Liu Qiao'e,Zhang Xuan,Ruan Jian,Wang Xiaojun,Liu Wendong,Kim Chan Kyung 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.7

To understand the role of dimethyl sulfoxide (DMSO) on the crystal growth morphology of 2,3,5,6-tetra(1H-tetrazol-5-yl)pyrazine (H4TTP), the vacuum morphology of H4TTP crystal was predicted by the Bravais–Friedel–Donnay–Harker (BFDH) and the attachment energy (AE) models. The growth morphology of H4TTP in DMSO solvent was predicted using a modified AE model. The results show that the main growth surfaces of H4TTP in vacuum are (1 0 0), (0 0 2), (0 1 1), and (1 1 0) surfaces. Among them, (1 0 0) surface is the most important growth surface. (0 0 2) surface is the roughest crystal surface, while (1 1 0) surface is the flattest. (1 1 0) surface grows rapidly, and (1 0 0) surface has the greatest morphological importance. The analysis of radial distribution function shows that (1 0 0) surface has the strongest hydrogen bonding interactions in the interface between H4TTP and DMSO solvent.

Flexible and Highly Sensitive Piezoresistive Pressure Sensor with Sandpaper as a Mold

Wendan Jia,Qiang Zhang,Yongqiang Cheng,Dong Zhao,Yan Liu,Wendong Zhang,Shengbo Sang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Flexible pressure sensors based on piezoresistive induction have recently become a research hotspot due to the simple device structure, low energy consumption, easy readout mechanism and excellent performance. For practical applications, flexible pressure sensors with both high sensitivity and low-cost mass production are highly desirable. Herein, this paper presents a high-sensitivity piezoresistive pressure sensor based on a micro-structured elastic electrode, which is low cost and can be mass-produced by a simple method of sandpaper molding. The microstructure of the electrode surface under external pressure causes a change in the effective contact area and the distance between the electrodes, which exhibits great pressure sensitivity. The test results show that the surface structure is twice as sensitive as the planar structure under low pressure conditions. This is because of the special morphology of silver nanowires (AgNWs), which exhibits the tip of nanostructures on the surface and realizes the quantum tunneling mechanism. The sensor has high sensitivity for transmitting signals in real time and it can also be used to detect various contact actions. The low cost mass production and high sensitivity of flexible pressure sensors pave the way for electronic skin, wearable healthcare monitors and contact inspection applications.

Selection and optimization of nutritional risk screening tools for esophageal cancer patients in China

Wen Dong,Xiguang Liu,Shunfang Zhu,Di Lu,Kaican Cai,Ruijun Cai,Qing Li,Jingjing Zeng,Mei Li 한국영양학회 2020 Nutrition Research and Practice Vol.14 No.1

BACKGROUND/OBJECTIVES: Malnutrition has multiple impacts on surgical success, postoperative complications, duration of hospital stay, and costs, particularly for cancer patients. There are various nutrition risk screening tools available for clinical use. Herein, we aim to determine the most appropriate nutritional risk screening system for esophageal cancer (EC) patients in China. SUBJECTS/METHODS: In total, 138 EC patients were enrolled in this study and evaluated by experienced nurses using three different nutritional screening tools, the Nutrition Risk Screening 2002 tool (NRS2002), the Patient-generated Subjective Globe Assessment (PG-SGA), and the Nutrition Risk Index (NRI).We compared sensitivity, specificity, positive and negative likelihood ratios, and Youden index generated by each of the three screening tools. Finally, cut-off points for all three tools were re-defined to optimize and validate the best nutritional risk screening tool for assessing EC patients. RESULTS: Our data suggested that all three screening tools were 100% sensitive for EC patients, while the specificities were 44.4%, 2.96%, and 59.26% for NRS 2002, PG-SGA, and NRI, respectively. NRI had a higher positive likelihood ratio as well as a higher area under the receiver operating characteristic curve compared to those of NRS 2002 and PG-SGA; although, all three tools had null negative likelihood ratios. After adjusting the cut-off points, the specificity and accuracy for all tools were significantly improved, however, the NRI remained the most appropriate nutritional risk screening system for EC patients. CONCLUSIONS: The NRI is the most suitable (highest sensitivity and accuracy) nutritional risk screening tool for EC patients. The performance of the NRI can be significantly improved if the cut-off point is modified according to the results obtained using MedCalc software.