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1.
A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm
is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on
degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations
have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily.
Aumann’s algorithm for developable surfaces is a special case of this paper.
Project supported by the National Basic Research Program (973) of China (No. 2004CB719400), the National Natural Science Foundation
of China (Nos. 60373033 and 60333010) and the National Natural Science Foundation for Innovative Research Groups (No. 60021201),
China 相似文献
2.
Trevor Owens 《Cultural Studies of Science Education》2009,4(4):929-943
One of the first places children encounter science and scientists is children’s literature. Children’s books about science
and scientists have, however, received limited scholarly attention. By exploring the history of children’s biographies of
Marie Curie and Albert Einstein, the two most written about scientist in children’s literature, this paper taps this unutilized
resource to cultivate a unique perspective on the history of gender and authority in science and science education. Through
analysis of explicit discussions of womanhood and science and implicit gendering of Curie and Einstein’s school experiences
within these books, this study demonstrates that while much has changed in how these stories are framed the gender of the
scientist is still central to how they are represented in children’s literature. 相似文献
3.
Anita Y.K. Poon Yiu-Chung Wong 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2008,6(3):33-55
Although Hong Kong’s education system has long been criticized as lacking in creativity and over-emphasising rote learning,
on the whole it has served Hong Kong well in the past years, breeding outstanding business, academic and political leaders
who continue to maintain Hong Kong’s competitive edge. The traditional elite schools have played a crucial role in the process.
The education reform, which is still on-going, aims to overhaul the entire system by introducing the “through-road” model.
To accomplish this, some mechanisms need to be changed. J.P. Farrell’s concepts of equality and equity, C.W. Mills’ concept
of elitism, and P. Bourdieu and J. Coleman’s concepts of cultural and social capital will be applied to analyse the consequences
of the reform. The paper argues that the education reform may be well-intentioned in eliminating some elements of inequality
and inequity in education, but that this comes at the expense of Hong Kong’s cultural and social capital and leads to the
development of new forms of inequality. 相似文献
4.
Aziz Choudry 《Cultural Studies of Science Education》2010,5(2):423-434
In response to Richardson Bruna’s “Mexican immigrant transnational social capital and class transformation: examining the
role of peer mediation in insurgent science”, this paper draws on the author’s research on organizing, mobilization and knowledge
production among adult im/migrant workers in Canada. While appreciative of the content and concerns of Richardson Bruna’s
argument, the paper argues for a clearer position on tensions between agency and structure, and class and capitalist social
relations in which to contextualize the schooling of immigrant children in today’s US classrooms. In addition, it explores
some implications of Mignolo’s (2000) work on the geohistory of knowledge, notably his concept of ‘border thinking’ for teachers, teacher education, and curricula.
Finally, the article suggests the potential of methodological frameworks and approaches of institutional ethnography (Smith
1987), political activist ethnography (Frampton et al. 2006) and global ethnography (Burawoy 2000) to inform research into this field. 相似文献
5.
How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel
principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three
or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between
the large aircraft component’s ball-head and the localizer’s ball-socket. The localizer is driven to achieve a new position
by compensation. Relatively, a support revising algorithm is proposed. The localizer’s ball-socket approaches the ball-head
based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head
spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage’s
ball-head into a localizer’s ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket
in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that
the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied
widely in the modern aircraft industry. 相似文献
6.
This paper is grounded in a deep appreciation of Nel Noddings’ “ethics of care” as an important contribution to moral philosophy
and moral education. We seek to offer some philosophical reflections that have the potential to strengthen this important
alternative to mainstream ethics and to how moral education might be conceived and practiced differently. After identifying
some ambivalence in Noddings’ own position toward abstract philosophy, and despite the practical reasons for this that we
share, we then find grounds for pressing in this speculative direction, some of which indeed accord with Noddings’ own statements
and philosophical concerns. To show how such further philosophical reflection upon her relational morality could help, we
focus on elaborating a perspective on ontological issues that we find in the work of Thomas Hill Green, a 19th century idealist, and seek to show its compatibility with Noddings’ more pragmatic stance. A concluding point addresses,
and dispels, a possible worry that the grand narrative structure of Green’s idealism might undercut Noddings’ aim of having
an ethic that is melioristic and open. 相似文献
7.
This paper is about the interaction between policy and practice, and about how competing policies contributed to a paradoxical
tension within that interaction in one school. Within a paradigm of educational renewal, the Singapore Ministry of Education
(MOE) has initiated a number of policies designed to give schools autonomy in designing and implementing programmes to achieve
optimal educational outcomes for its students. Among these are READ! Singapore, Teach Less, Learn More and the School Excellence
Model. In this context, we review an MOE initiated Extensive Reading (ER) programme in one school. Despite such innovative
policies, Dewey Secondary School’s [The names of the school and individuals have been changed to protect their privacy.] pedagogical
and literacy practices continue to be largely influenced by other dominant features of Singapore’s and the school’s own educational
culture—an exam-oriented focus that prioritises outcome and skill-based pedagogy and the school’s historical practice of restricting
literacies. Competing policies as interpreted by the school and diverse stakeholders result in a morphed ER programme—an adaptation
of a reading programme that reflects the programme intent overtly but one that collides at other times, and as a result, is
pulled in different directions. The story is, thus, one of ‘policies of promise and practices of limit’. 相似文献
8.
Chaya Herman 《Higher Education》2010,59(4):489-506
This paper examines the relationship between political change and epistemologies and methodologies employed at doctorate level.
It does so by analysing the range of topics, questions and methodologies used by doctoral students at the University of Pretoria’s
Faculty of Education between 1985 and 2005—a time-frame that covers the decade before and the decade after South Africa’s
historical transition to democracy in 1994. During this period the composition of doctoral students at that faculty changed
from being largely white and male to a more diverse population in terms of gender and race. A crucial shift took place after
2000 with the arrival of a Black dean who sought to introduce a transformational shift. The paper makes use of Karmon’s notion
of epistemic environment, which refers to the way knowledge is conceptualised at institutional level. The data shows how the
authoritarian and regulated epistemic environment that shaped the conception of knowledge at the faculty until 2000 created
doctoral dissertations that aimed to correct and guide the society but lacked critical discourse and relevance to South Africa’s
political, social and educational context. While the transition to democracy in 1994 produced merely semantic changes, if
any, the strong internal initiative to change the research culture from 2000 onwards has managed to shift basic notions of
truth and knowledge and the understanding of the role and nature of research. This movement was, however, constrained by the
institution’s long-established epistemic environment. 相似文献
9.
William Yat Wai Lo 《Higher Education》2009,58(6):733-745
This paper aims to investigate the possible framework for encouraging the presence of local dimensions in an internationalised
and globally competitive system by using Taiwan’s higher education system as a case. It begins by discussing the notion of
internationalisation and its implications for higher education. It then turns to look at Taiwan’s responses to these global
developments. It also reviews different opinions on the position and importance of local dimensions in the world of globalised
higher education. Based on these perspectives, the paper advocates promoting the concept of state-building in Taiwan’s as
well as in other higher education systems for preserving or even strengthening the local dimensions of individual academic
systems operating in the international knowledge network. 相似文献
10.
Frank Uhlig 《Educational Studies in Mathematics》2002,50(3):335-346
We describe how elementary Linear Algebra can be taught successfully while introducing students to the concept and practice
of ‘mathematical proof’.This is done badly with a sophisticated Definition–Lemma–Proof–Theorem–Proof–Corollary(DLPTPC) approach;
badly – since students in elementary Linear Algebra courses have very little experience with proofs and mathematical rigor.
Instead, the subjects and concepts of Linear Algebra can be introduced in an exploratory and fundamentally reasoned way. One
seemingly successful way to do this is to explore the concept of solvability of linear systems first via the row echelon form
(REF). Solvability questions lead to row and column criteria for a REF that can be used repeatedly to: compute subspaces,
settle linear (in)dependence, find inverses, perform basis change, compute determinants, analyze eigensystems etc. If these
subjects are explained heuristically from the first principles of linear transformations, linear equations, and the REF, students
experience the power of a concept–built approach and reap the benefit of deep math understanding. Moreover, early ‘salient
point’ proofs lead to an intuitive understanding of ‘math proof’. Once the basic concept of ‘proof’ is ingrained in students,
more abstract proofs, even DLPTPC style expositions, on normal matrices, the SVD etc. become accessible and understandable
to sophomore students. With the help of this gentle early approach, the concept and construct of a ‘math proof’ becomes firmly
embedded in the students' minds and helps with future math courses and general scientific reasoning.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Marida Ergazaki Konstantina Saltapida Vassiliki Zogza 《Research in Science Education》2010,40(5):699-715
This paper is concerned with highlighting young children’s ideas about the nature, location and appearance of germs, as well
as their reasoning strands about germs’ ontological category and biological functions. Moreover, it is concerned with exploring
how all these could be taken into account for shaping a potentially fruitful learning environment. Conducting individual,
semi-structured interviews with 35 preschoolers (age 4.5–5.5) of public kindergartens in the broader area of Patras, we attempted
to trace their ideas about what germs are, where they may be found, whether they are good or bad and living or non-living
and how they might look like in a drawing. Moreover, children were required to attribute a series of biological functions
to dogs, chairs and germs, and finally to create a story with germs holding a key-role. The analysis of our qualitative data
within the “NVivo” software showed that the informants make a strong association of germs with health and hygiene issues,
locate germs mostly in our body and the external environment, are not familiar with the ‘good germs’-idea, and draw germs
as ‘human-like’, ‘animal-like’ or ‘abstract’ entities. Moreover, they have significant difficulties not only in employing
biological functions as criteria for classifying germs in the category of ‘living’, but also in just attributing such functions
to germs using a warrant. Finally, the shift from our findings to a 3-part learning environment aiming at supporting preschoolers
in refining their initial conceptualization of germs is thoroughly discussed in the paper. 相似文献
12.
Keiichi Takaya 《Interchange》2008,39(1):1-19
Though a psychologist by training, Jerome Bruner has always been, and still is, one of the leading figures in education. His
theory of education in the 1960s and the 1970s directly influenced the programs of education formulated during those decades.
The influence of his theory after the 1980s seems to be less direct, and some who read his 1996 book, The Culture of Education, may have an impression that his educational theory has changed. In this paper, I will review the historical significance
of the changes in Jerome Bruner’s work over his career and their implications for curriculum theory. I will argue that there
are, in fact, significant changes in Bruner’s views. 相似文献
13.
This article reports research from a 3 year digital learning project to unite conceptual change and scientific reasoning in
the learning unit of combustion. One group of students had completed the course combining conceptual change and scientific
reasoning. The other group of students received conventional instruction. In addition to the quantitative data, six students
from each group were interviewed to evaluate their conceptual change, correct concepts and scientific reasoning. Results indicate
that the experimental group’s students significantly outperformed the conventional group on the Combustion Achievement Test
(CAT), Scientific Reasoning Test (SRT) and Combustion Dependent Reasoning Test (CDRT). Moreover, the experimental group’s
students use higher levels of scientific reasoning more frequently and changed their alternative concepts more successfully
than did the conventional group. Furthermore, once the experimental group’s students’ successfully changed their conceptions,
their concepts tended to be more stable than the conventional group’s students, even after the 6th week of learning. These
results demonstrate that combining conceptual change and scientific reasoning indeed improves students’ conceptual change
and scientific reasoning ability more effectively than conventional instruction. 相似文献
14.
Lena Löfgren Gustav Helldén 《International Journal of Science and Mathematics Education》2008,6(3):481-504
In order to develop successful teaching approaches to transformations of matter, we need to know more about how young students
develop an understanding of these processes. In this longitudinal study, we followed 25 students from 7 to 13 years of age
in their reasoning about transformations of matter. The questions addressed included how the students’ understanding of transformations
of matter changed and how we can make sense of individual learning pathways. In interviews performed once or twice every year
the students described and explained three situations: fading leaves left on the ground, a burning candle, and a glass of
water covered with a glass plate on which some mist had formed. When analysing the interviews, we found a common pathway of
how the students’ ideas changed over the years in each one of the situations. When analysing individual student’s interviews
with Ausubel’s assimilation theory we could discern subordinate, superordinate and combinatorial learning. How these findings
can contribute to an improvement of teaching about transformations of matter is discussed. 相似文献
15.
Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors 总被引：1，自引：0，他引：1
SLADE Paul G LI Wang-pei MAYO Stephen SMITH R. Kirkland TAYLOR Erik D 《浙江大学学报(A卷英文版)》2007,8(3):335-342
The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments. 相似文献
16.
This article focuses on an experienced high school mathematics teacher who changed her practice without participating in planned
interventions aimed at producing this change. It reports on the nature of the teacher’s change from her perspective and an
interpretation and understanding of the change from the researcher’s perspective. It illustrates how meaningful change can
occur when the process is initiated and rooted in the teacher’s experience based on a tension in self and/or practice that
is personal and real to him or her. It discusses three types of change that are possible depending on the level of engagement
of the teacher in professional development opportunities: instrumental change, conceptual change, and foundational change. 相似文献
17.
Claire Margolinas Lalina Coulange Annie Bessot 《Educational Studies in Mathematics》2005,59(1-3):205-234
Our research is concerned with teacher’s knowledge, and especially with teacher’s processes of learning, in the classroom,
from observing and interacting with students’ work. In the first part of the paper, we outline the theoretical framework of
our study and distinguish it from some other perspectives. We argue for the importance of distinguishing a kind of teacher’s
knowledge, which we call didactic knowledge. In this paper, we concentrate on a subcategory of this knowledge, namely observational didactic knowledge, which grows from teacher’s observation and reflection upon students’ mathematical activity in the classroom. In modeling
the processes of evolution of this particular knowledge in teachers, we are inspired, among others, by some general aspects
of the theory of didactic situations. In the second part of the paper, the model is applied in two case studies of teachers
conducting ordinary lessons. In conclusion, we will discuss what seems to be taken into account by teachers as they observe
students’ activity, and how in-service teacher training can play a role in modifying their knowledge about students’ ways
of dealing with mathematical problems. 相似文献
18.
Todd Campbell Shaing Kwei Wang Hui-Yin Hsu Aaron M. Duffy Paul G. Wolf 《Journal of Science Education and Technology》2010,19(5):505-511
This position paper proposes the enhancement of teacher and student learning in science classrooms by tapping the enormous
potential of information communication and technologies (ICTs) as cognitive tools for engaging students in scientific inquiry.
This paper serves to challenge teacher-held assumptions about students learning science ‘from technology’ with a framework
and examples of students learning science ‘with technology’. Whereas a high percentage of students are finding their way in
using ICTs outside of school, for the most part they currently are not doing so inside of school in ways that they find meaningful
and relevant to their lives. Instead, the pedagogical approaches that are most often experienced are out-of-step with how
students use ICTs outside of schools and are not supportive of learning framed by constructivism. Here we describe a theoretical
and pedagogical foundation for better connecting the two worlds of students’ lives: life in school and life outside of school.
This position paper is in response to the changing landscape of students’ lives. The position is transformative in nature
because it proposes the use of cyber-enabled resources for cultivating and leveraging students new literacy skills by learning
‘with technology’ to enhance science learning. 相似文献
19.
Meaningful discussion that facilitates reflective thinking can be initiated when learners raise thoughtful questions or provide
critical feedback; however, generating effective questions requires a certain level of domain knowledge and metacognitive
skills of the question-askers. We propose a peer-questioning scaffolding framework intended to facilitate metacognition and
learning through scaffolding effective peer-questioning in online discussion. This framework assumes that novice students
who lack domain and metacognitive knowledge can be scaffolded to generate meaningful interactions at an early stage of learning
and the resulting peer-generated adaptive questions can facilitate learners’ metacognition. Thus, this study investigated
the effects of providing online scaffolding for generating adaptive questions to peers during online small group discussion.
A field experimental time-series control-group design was employed as a mixed model for the research design. Thirty-nine college
students from an online introductory class on turfgrass management participated in the study. The findings revealed that the
scaffolds were useful to increase the frequency of student questioning behavior during online discussion. For some students,
the online guidance reportedly served as “a starting point” to generate questions when they had difficulty asking questions.
However, the guidance did not improve the quality of questions and thus learning outcomes. The interview data indicated that
peer-generated adaptive questions served a critical role in facilitating learner’s reflection and knowledge reconstruction.
Further study should focus on the quality improvement of peer-generated questions while considering adaptive and dynamic forms
of scaffolding and intermediate factors such as prior knowledge, metacognition, task complexity, and scaffolding type. 相似文献
20.
Cristine A. Smith Rebecca Paulson Stone Sarah Kahando 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2012,25(2):533-555
Delaying girls’ early marriage is a critical public health and education goal in developing countries, in which their own or their mothers’ education may play an important role. This paper reviews the existing evidence of any relationship between girls’ schooling or women’s literacy education and delayed marriage for themselves or their daughters. The majority of research reports focus on the correlation between girls’ schooling and brides’ age at first marriage. But it is conceivable that adult women’s/mothers’ literacy education also has considerable influence on the age at which their daughters are married. Since this aspect has hitherto not been explicitly investigated, the authors propose a model – based on relevant research about the outcomes of girls’ schooling and women’s literacy education – of the mechanisms that mediate between women’s education and delayed marriage for their daughters. The authors argue for research that will inform policy makers interested in helping girls complete secondary schooling about the potential contributions of adult women’s literacy education to this goal. 相似文献