Some numerical tests for an alternative approach to optimal feedback control

We test a recently proposed approach to optimal feedback control of nonlinear systems leading to an iterative descending strategy [24]. We start by discussing the numerical implementation of this strategy, and propose a number of improvements that can speed up the computation process by up to two orders of magnitude. The resulting algorithm is then applied to a series of test problems of increasing complexity. Results seem to show that this can be a promising strategy to bear in mind for more realistic situations.     

骨髓增生异常综合征的中西医治疗

骨髓增生异常综合征(MDS)以难治性全血细胞减少和易转化为急性白血病为特征.患者的预后、合并症和年龄是决定治疗策略时必须考虑的因素.治疗策略经常以支持治疗为主,包括造血细胞生成因子、输注红细胞和血小板以及抗感染治疗.另外诱导分化、免疫抑制治疗、刺激造血、靶向治疗、化疗、异基因骨髓移植等根据具体病情选择应用.我们明确提出"气阴两虚,血瘀内阻"的中医复合证候为MDS临床主证,以"益气养阴活血"为治疗大法,制成"益髓颗粒剂",进行了大量实验及临床研究,获得了确切疗效.     

Rethinking argumentation-teaching strategies and indigenous knowledge in South African science classrooms

Our response to Hewson and Ogunniyi’s paper focuses, on the one hand, on some of the underlying tensions associated with alinging indigenous knowledge systems with westernized science in South African science classrooms, as suggested by the new, post-apartheid, curriculum. On the other hand, the use of argumentation as a vehicle to accomplish the alignment when the jury is still out on the appropriateness of argumentation as a pedagogical and research tool heightens the tension. We argue that the need for education stakeholders from indigenous heritages to value, know and document their own indigenous knowledge becomes paramount. The textualizing of indigenous knowledge, as has been done in western science, will create repositories for teachers to access and may help with the argumentation strategies such as advocated by the authors.     

对地理新课程"三维目标"整合的认识

从认识论的角度看,人类对地理知识的学习和掌握涉及不同的水平层次:事实性知识、概念性知识、方法性知识和价值性知识,这从一个侧面表现出地理新课程目标的内涵:即涵盖事实性知识、原理性知识,又要包括地理思想方法、地理观念,以及科学的价值观念,具体表现为"知识与技能"、"过程与方法"和"情感态度价值观"三维目标."三维目标"是一个目标中的三个维度,其中知识与技能是载体和基础,过程和方法是依托,情感、态度和价值观目标是终极归宿.三者相互联系相互依赖构成一个不可分割的有机整体,教学中应该进行整合设计和表述.     

警察体育课预防下腰痛的实验研究

由于警察的职业特点,警察院校学员下腰痛的发病率、发病原因及治疗方面都有其特殊性.在基础体能、散打、摔跤及射击等项目中存在着相对高的下腰痛发病率.下腰痛的发生原因主要有脊柱因和非脊柱因两类.警察下腰痛的原因多为肌肉损伤和韧带拉伤、椎间盘退行性疾病、脊椎峡部崩裂等.警察院校学员下腰痛要选择合理的预防手段.本课题通过实验方法,寻找警察体育课科学预防下腰痛的有效方法.     

A CASE STUDY OF ELEMENTARY BEGINNING MATHEMATICS TEACHERS’ EFFICACY DEVELOPMENT

The main purpose of this research was to explore the developmental process of and possible changes in beginning elementary mathematics teachers’ efficacy. Beginning teachers with and without mathematics and science backgrounds were also compared to explore differences in their efficacy development. A multiple-case study method with a process and recursive design was employed in this study. The participants were six beginning elementary mathematics teachers purposefully selected from Taichung, Taiwan. Data were collected through interviews, recordings, observations, and reflection notes and then analyzed by immersion and editing analytic techniques. Based on the data analysis, a five-gradation developmental model and its characteristics of elementary beginning mathematics teacher efficacy was developed and proposed. The findings demonstrated the developmental process of this five-gradation model and its continuity and cyclical nature. Moreover, beginning mathematics teachers, who were at the same efficacy levels, tended to exhibit substantial similarities but slight differences in their developmental processes. This study also verified that the construct of internal and external factors played a significant role in cyclically contributing to continuous efficacy development. The implications of beginning mathematics teachers’ efficacy and their professional development that derived from the findings and discussions were proposed, as well as a recommendation for further exploration on their efficacy development.     

The implementation of a new policy on teacher appraisal in Portugal: how do teachers experience it at school?

This paper draws upon a broader piece of research aimed at investigating the implementation process of a recent policy on teacher appraisal in Portugal. Two case studies were carried out and a combination of methods for data collection was used. Findings suggest that teachers?? perceptions are marked by uncertainty and scepticism. Amongst the most critical issues are the lack of recognition of the appraisers, the bureaucratic and summative dimension, and the lack of necessary conditions to put it into practice. However, some positive aspects were also identified, namely the emergence of debates within the teaching profession, the opportunity to reflect upon teachers?? practice and to change previous teacher appraisal system.     

100MHz数字频率计的设计

100MHz数字频率计用VHDL语言编程设计,主要由五个模块组成,分别是测频控制信号发生器、十进制计数器、32位锁存器、分频器、动态扫描译码驱动器模块五部分构成.选用分频器将工作时钟分频后,用测频器测频,将被测频率信号经脉冲整形电路后作为计数器的计数脉冲,加入计数器的输入端,测量一定闸门时间内被测信号的脉冲个数,并将其计数值锁存进锁存器中,最后通过动态扫描译码器读出数值,该频率计精度高,可用于频率测量、机械转速测量等领域.     

Turkish Students' Conceptions about the Simple Electric Circuits

In this study, the Turkish students' understanding level of electric circuits consisting of two bulbs and one battery was investigated by using open-ended questions. Two-hundred fifty students, whose ages range from 11 to 22, were chosen from five different groups at primary, secondary and university levels in Trabzon in Turkey. In analyzing students' drawings and explanations, both qualitative and quantitative methodologies were exploited. The unipolar model (Model A), the clashing currents model (Model B), the current consumed model (Model C) and the scientist model with current conserved (Model D) determined from the related literature were used to categorize the students' answers. The results showed that the Turkish students have many misconceptions about electric circuits. Also, it is found out that especially Model A was widespread accepted among the students in group 1 (5th grade) and half of the students in group 3 (9th grade) has an understanding of electric circuits as it is in Model C.