Command filtered adaptive neural network synchronization control of fractional-order chaotic systems subject to unknown dead zones     

Shumin Ha  Liangyun Chen  Heng Liu 《Journal of The Franklin Institute》2021,358(7):3376-3402

Command filters are essential for alleviating the inherent computational complexity (ICC) of the standard backstepping control method. This paper addresses the synchronization control scheme for an uncertain fractional-order chaotic system (FOCS) subject to unknown dead zone input (DZI) based on a fractional-order command filter (FCF). A virtual control function (VCF) and its fractional-order derivative are approximated by the output of the FCF. In order to handle filtering errors and obtain good control performance, an error compensation mechanism (ECM) is developed. A radial basis function neural network (RBFNN) is introduced to relax the requirement of the uncertain function must be linear in the standard backstepping control method. The construction of a VCF in each step satisfies the Lyapunov function to ensure the stability of the corresponding subsystem. By using the bounded information to cope with the unknown DZI, the stability of the synchronization error system is guaranteed. Finally, simulation results verify the effectiveness of our methods.  相似文献   

A preliminary evaluation of VEGF-A,VEGFR1 and VEGFR2 in patients with well-controlled type 2 diabetes mellitus   总被引：4，自引：0，他引：4  

Barbara RUSZKOWSKA-CIASTEK  Alina SOKUP  Maciej W. SOCHA  Zofia RUPRECHT  Lidia HA?AS  Barbara GóRALCZYK  Krzysztof GóRALCZYK  Gra?yna GADOMSKA  Danuta RO?? 《Journal of Zhejiang University. Science. B》2014,15(6):575-581

Objective

Decompensated chronic hyperglycemia often leads to late microvascular complications such as retinopathy, diabetic foot syndrome, and diabetic kidney disease. The aim of this study was to determine the concentration of vascular endothelial growth factor A (VEGF-A) and its receptors in patients with well-controlled diabetes.

Methods

The study was conducted on 31 patients with well-controlled type 2 diabetes without micro-or macroangiopathy. Thirty healthy volunteers were enrolled in a control group. Serum concentrations of VEGF-A, VEGF receptors 1 and 2 (VEGFR1 and VEGFR2), fasting glucose, and lipid profiles were measured, and the plasma concentration of glycated hemoglobin (HbA1c) was determined.

Results

No significant differences were observed between the concentration of VEGF-A, VEGFR1 or VEGFR2 in the subject group and that in the control group. Positive correlations were noted between the levels of VEGF-A, VEGFR2, and triglyceride, and there was a negative correlation between the levels of VEGFR2 and high-density lipoprotein (HDL)-cholesterol in the study group.

Conclusions

The concentrations of VEGF-A and its receptors 1 and 2 in patients with well-controlled diabetes are comparable to those of healthy individuals, which may indicate that appropriate control of glucose levels delays the occurrence of vascular complications. A negative correlation between VEGFR2 and HDL-cholesterol levels, and positive correlations between VEGF-A, VEGFR2, and triglyceride levels, suggest that lipid abnormalities occurring in diabetes may be involved in the modulation of angiogenesis.  相似文献   

The influence of unsupervised time on elementary school children at high risk for inattention and problem behaviors     

Kyoung-Sae Na  Soyoung Irene Lee  Hyun Ju Hong  Myoung-Ja Oh  Geon Ho Bahn  Kyunghee Ha  Yun Mi Shin  Jungeun Song  Eun Jin Park  Heejung Yoo  Hyunsoo Kim  Yun-Mi Kyung 《Child abuse & neglect》2014

In the last few decades, changing socioeconomic and family structures have increasingly left children alone without adult supervision. Carefully prepared and limited periods of unsupervised time are not harmful for children. However, long unsupervised periods have harmful effects, particularly for those children at high risk for inattention and problem behaviors. In this study, we examined the influence of unsupervised time on behavior problems by studying a sample of elementary school children at high risk for inattention and problem behaviors. The study analyzed data from the Children's Mental Health Promotion Project, which was conducted in collaboration with education, government, and mental health professionals. The child behavior checklist (CBCL) was administered to assess problem behaviors among first- and fourth-grade children. Multivariate logistic regression analysis was used to evaluate the influence of unsupervised time on children's behavior. A total of 3,270 elementary school children (1,340 first-graders and 1,930 fourth-graders) were available for this study; 1,876 of the 3,270 children (57.4%) reportedly spent a significant amount of time unsupervised during the day. Unsupervised time that exceeded more than 2 h per day increased the risk of delinquency, aggressive behaviors, and somatic complaints, as well as externalizing and internalizing problems. Carefully planned afterschool programming and care should be provided to children at high risk for inattention and problem behaviors. Also, a more comprehensive approach is needed to identify the possible mechanisms by which unsupervised time aggravates behavior problems in children predisposed for these behaviors.  相似文献   

Book Review: Programming and Direct Viewer Payment for Television: The Case of Canal Plus Spain. Media Markets Monograph     

Louisa Ha 《媒体管理杂志》2013,15(1-2):86-88

  相似文献   

Early Childhood Teacher Learning Through a Professional Development School Program in Hong Kong     

Lai Ha Yuen 《Journal of Early Childhood Teacher Education》2013,34(1):72-83

Emphasis on continuing professional development is seen as an important aspect of educational reform at all levels of education. In recent years, a number of colleges and universities have established partnerships for the professional development of teachers at the elementary and secondary levels. However, there have been few partnerships within the Professional Development School Program (PDS) established in early childhood settings. Thus, this paper explores the growth and development of two kindergarten teachers after their school participated in a PDS in Hong Kong.  相似文献   

Crossing borders between science and religion: Muslim Indonesian biology teachers’ perceptions of teaching the theory of evolution     

Rachmatullah  Arif  Park  Soonhye  Ha  Minsu 《Cultural Studies of Science Education》2022,17(2):589-624

  相似文献   

理想的网络教室终端机配置     

哈振中 《中国教育技术装备》2009,(21):101-102

现代教学对网络教室的依赖性越来越大,保证网络教学软件环境的高效、安全、清洁运行显得尤为重要.就这一问题进行较为详细的分析和论述,并提出较为合理的解决方法.  相似文献   

A comparison of attitudes related to global citizenship between Korean- and US-educated Korean university students     

Young Ha Cho  Eunlim Chi 《Asia Pacific Journal of Education》2015,35(2):213-225

This study compared the perceptions of Korean-national university students studying in Korea and in the US regarding global citizenship. The study sample consisted of two distinct groups: students who had received their education exclusively in Korea and students who were born in Korea but had studied in the US since secondary school. By applying latent mean analysis, the study found that the US-educated Koreans had higher levels of trust and national identity, whereas the Koreans had higher levels of social responsibility and participation. The results suggest that university students of the same nationality who experience different social environments may perceive global citizenship in dissimilar ways. For future investigations, we suggest a longitudinally designed experimental study, which may reveal a causal relationship between the social experiences of university students who study abroad and their perceptions of global citizenship. In addition, future investigations should consider how these students are assimilated into and adapt to diverse interactions on multicultural campuses.  相似文献   

Clicker Score Trajectories and Concept Inventory Scores as Predictors for Early Warning Systems for Large STEM Classes   总被引：1，自引：1，他引：0  

Un Jung Lee  Gena C. Sbeglia  Minsu Ha  Stephen J. Finch  Ross H. Nehm 《Journal of Science Education and Technology》2015,24(6):848-860

  相似文献   

Multiple Classrooms of Life: English,Ideology and ‘Sparkle’ Moments     

Phan Le Ha  Bao Dat 《Changing English: An International Journal of English Teaching》2019,26(3):238-251

ABSTRACT

This essay comprises multiple sets of dialogues between us as colleagues and friends as we revisit the question of the status of English as a global language. Through the metaphor ‘multiple classrooms of life’, we share reflections and narratives arising out of our experiences with English that are embedded in our professional work, scholarship, pedagogy and creative interests. Our discussion encompasses a range of artefacts, including excerpts from our diaries, poems, vignettes, visuals, letters, songs and anecdotes. This amalgam of materials represents our personal engagement with English, as distinct from treating the spread of English simply as a metanarrative played out at a remove from personal experience. We reconstruct ‘sparkle moments’ arising from personal encounters and social interactions that have caused us to reflect on the role of English in our lives. We thus focus on ideology as personally felt and lived from within and through inter-personal interactions.  相似文献