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1.
Application of Hamiltonian system for two-dimensional transversely isotropic piezoelectric media 总被引：2，自引：2，他引：2
INTRODUCTION The traditional method of solving solutions of the transversely isotropic piezoelectric media belongs to Lagrange formulation so that the method of sepa- ration of variables cannot be applied due to the in- volvement of high order partial differentiation in the Euclidian space and is difficult for some problems. New theoretical system or method is a key for the investigation of piezoelectric materials. Since the foundational equations (Sosa and Pak, 1990) in transversely iso… 相似文献
2.
The symplectic approach proposed and developed by Zhong et al. in 1990s for elasticity problems is a rational analytical method, in which ample experience is not needed as in the conventional semi-inverse method. In the symplectic space, elasticity problems can be solved using the method of separation of variables along with the eigenfunction expansion technique, as in traditional Fourier analysis. The eigensolutions include those corresponding to zero and nonzero eigenvalues. The latter group can be further divided into α-and β-sets. This paper reformulates the form of β-set eigensolutions to achieve the stability of numerical calculation, which is very important to obtain accurate results within the symplectic frame. An example is finally given and numerical results are compared and discussed. 相似文献
3.
The symplectic approach proposed and developed by Zhong et al. in 1990s for elasticity problems is a rational analytical method, in which ample experience is not needed as in the conventional semi-inverse method. In the symplectic space, elasticity problems can be solved using the method of separation of variables along with the eigenfunction expansion technique, as in traditional Fourier analysis. The eigensolutions include those corresponding to zero and nonzero eigenvalues, The latter group can be further divided into α- and β-sets. This paper reformulates the form of β-set eigensolutions to achieve the stability of numerical calculation, which is very important to obtain accurate results within the symplectic frame. An example is finally given and numerical results are compared and discussed. 相似文献
4.
Pia Niemelä Ville Isomöttönen Lasse Lipponen 《Education and Information Technologies》2016,21(1):105-122
Education is increasingly enhanced by technology, and at the same time, the rapid pace of technology innovation and growing demand of consumers introduces challenges for providers of technological learning solutions. This paper investigates Finnish small and medium size companies who either develop or deliver technological solutions for education. Twelve companies were interviewed in order to capture the entrepreneurial narratives of successful design of learning solutions. Data was analyzed based on a conceptual framework. The framework draws on the situation awareness concept, meaning that we seek to answer the question how the participant enterprises examine relevant elements in their environment with regard to their development process. The results show that all the mature companies included in the study have well balanced situation awareness, but amongst the incubating and accelerating enterprises, balanced profiles are rare. 相似文献
5.
Maria Angela Shiakalli 《International Journal of Early Years Education》2012,20(4):315-331
Could problem solving be the object of teaching in early education? Could appropriate teaching interventions develop to scaffold children's efforts to solve problems? These were the central questions of this article. The sample consisted of 18 children attending public pre-school in Cyprus. The problem they were asked to solve was to find all solutions of the pentomino. The children's problem solving was supported by graphically representing their solutions on squared paper. The findings show that children responded positively to the problem and were successful in finding all solutions for the specific problem. The graphical representation of the solutions and the forms of teacher–children and children–children interactions played an important role in the positive outcome of the activity. 相似文献
6.
K. F. MARTIN 《European Journal of Engineering Education》1986,11(4):451-457
CAE has enabled vibrational problems, which were regarded as intractable 20 years ago, to be solvable by students using computational support. The paper describes a problem set to final year undergraduates which concerns the torsional vibrational response of a three degrees of freedom system which is subjected simultaneously to three different arbitrarily varying torques. The solution involves the use of standard library routines for matrix multiplication and eigensolutions, a Runge-Kutta routine to solve a second order differential equation and general competence in writing software. 相似文献
7.
In this paper, a three-parameter family of self-similar and weak solutions are constructed rigorously in two space dimensions for all positive time to the Euler equations with axisymmetric and radial negative initial velocity for the Chaplygin gas. Under the axisymmetry and self-similar assumptions, the equations are reduced to a system of three ordinary differential equations, from which we obtain structures of solutions besides their existence. The solutions exhibit some phenomena, such as formation and evolution of black hole, expansion and explosive expansion, in the evolution of universe. 相似文献
8.
Heather L. Petcovic Herb Fynewever Charles Henderson Jacinta M. Mutambuki Jeffrey A. Barney 《Research in Science Education》2013,43(2):437-455
Grading practices can send a powerful message to students about course expectations. A study by Henderson et al. (American Journal of Physics 72:164–169, 2004) in physics education has identified a misalignment between what college instructors say they value and their actual scoring of quantitative student solutions. This work identified three values that guide grading decisions: (1) a desire to see students’ reasoning, (2) a readiness to deduct points from solutions with obvious errors and a reluctance to deduct points from solutions that might be correct, and (3) a tendency to assume correct reasoning when solutions are ambiguous. These authors propose that when values are in conflict, the conflict is resolved by placing the burden of proof on either the instructor or the student. Here, we extend the results of the physics study to earth science (n?=?7) and chemistry (n?=?10) instructors in a think-aloud interview study. Our results suggest that both the previously identified three values and the misalignment between values and grading practices exist among science faculty more generally. Furthermore, we identified a fourth value not previously recognized. Although all of the faculty across both studies stated that they valued seeing student reasoning, the combined effect suggests that only 49% of faculty across the three disciplines graded work in such a way that would actually encourage students to show their reasoning, and 34% of instructors could be viewed as penalizing students for showing their work. This research may contribute toward a better alignment between values and practice in faculty development. 相似文献
9.
Torulf Palm 《Educational Studies in Mathematics》2008,67(1):37-58
The study presented in this paper seeks to investigate the impact of authenticity on the students’ disposition to make necessary
real world considerations in their word problem solving. The aim is also to gather information about the extent to which different
reasons for the students’ behaviors are responsible for not providing solutions that are consistent with the ‘real’ situations
described in the word problems. The study includes both written solutions to word problems and interview data from 161 5th
graders. The results show an impact of authenticity on both the presence of ‘real life’ considerations in the solution process
and on the proportion of written solutions that were really affected by these considerations. The students’ frequent use of
superficial solution strategies and their beliefs about mathematical word problem solving were found to be the main reasons
for providing solutions that are inconsistent with the situations described in the word problems. 相似文献
10.
Bengt Persson 《欧洲特需教育杂志》2013,28(4):337-347
According to Swedish legislation as well as laws pertaining to disabled citizens, Swedish schools are to be accessible for all children and adolescents. This implies that disabilities of any type must not be allowed to prevent students from completing their schooling on their own terms. The purpose of this research was to study the degree to which the Swedish school is accessible for all students. A total 200 professionals and politicians were interviewed alongside more than 30 upper secondary school students. The results show that the ambition level is high with regard to adapting educational programmes for the disabled student group, especially in the rhetoric of politicians and civil servants. However, in practice, teachers and head teachers have considerably more difficulty in delivering to students satisfactory schooling. This is often due to conflict between the striving for inclusion and the difficulty adapting learning environments during everyday classroom instruction. By use of institutional theory the study demonstrates that intentions as described of responsible politicians are altered in the system when confronted with the institutional reality. Schools’ meeting the natural variation of difference in the student group causes complications in educational work in which various solutions are attempted. When educational differentiation is found wanting in attempts to meet students’ various needs, various types of special solutions are sought, which have the objective of reducing heterogeneity among the students. This type of organisational differentiation seems accepted and legitimised where it concerns students having various kinds of school‐related difficulties, while seeming to create a disadvantage for some other students. One should understand this as thought coercion, where pressure from professionals in schools leaves little room for other strategies and in which the concept of the inclusive school is challenged. 相似文献
11.
Three professors share their solutions to the problem of focusing students on the assessments required in their classes, lest specification charts show students the specific concepts, principles, and problems that will be included on multiple choice tests. Rubrics developed for assigned work are demonstrated as ways to increase student expectations and to direct their explorations. Negotiated rubrics are used to involve students in the setting of standards for work in their own classes. Advantages for students and professors in using the methods are offered. 相似文献
12.
The C programming language is expressive and flexible, but not safe; as its expressive power and flexibility are obtained through unsafe language features, and improper use of these features can lead to program bugs whose causes are hard to identify. Since C is widely used, and it is impractical to rewrite all existing C programs in safe languages, so ways must be found to make C programs safe. This paper deals with the unsafe features of C and presents a survey on existing solutions to m… 相似文献
13.
高校贫困生作为一个相对弱势的学生群体,如何帮助他们度过困难,健康发展,顺利完成学业,是高校要面对的一个带有共性的问题。本文就我校对经济困难学生的资助工作及工作中存在的困难和矛盾进行了分析,提出了解决问题的一点思路。 相似文献
14.
何斌 《蒙自师范高等专科学校学报》2008,6(5):19-24
利用平面动力系统理论将四类广义sine-Gordon和广义sinh-Gordon方程的行波解进行分类.在一个四参数空间上,得到了不同区域的所有可能的边界行波和它们的精确的显性参数表示. 相似文献
15.
陈源 《衡阳师范学院学报》2005,26(3):7-9
本文研究了含参数最优化问题解的通有唯一性。针对目标函数空间，采用了函数的上方图形拓扑，在目标函数仅仅关于第一变元下半连续的条件下，我们得出含参数最优化问题的解具有通有唯一性。 相似文献
16.
调查表明,最近几年我国“剩女”数量呈现不断增加的趋势。从社会、心理等多个角度分析了“剩女”产生的原因,提出了解决“剩女”问题的建议,希望能通过社会各界的关心、帮助,解决好大龄未婚女性的婚姻问题,以利于构建和谐社会。 相似文献
17.
Wu‐Yuin Hwang Nian‐Shing Chen Rustam Shadiev Jin‐Sing Li 《British journal of educational technology : journal of the Council for Educational Technology》2011,42(6):1016-1028
Previous studies have demonstrated that making annotations can be a meaningful and useful learning method that promote metacognition and enhance learning achievement. A web‐based annotation system, Virtual Pen (VPEN), which provides for the creation and review of annotations and homework solutions, has been developed to foster learning process among students. In order to explore the effects of reviewing annotations and homework solutions on learning achievement, a quasi‐experiment was conducted with VPEN in a math class over a period of 4 months. It was found that reviewing own text annotations has a significant influence on learning achievement; while on the contrary, reviewing peers' text annotations has no significant influence on learning achievement. Our results show that students gain more from reviewing their own annotations than from reviewing the annotations made by peers, a contrast which reveals that annotations hold additional meaning for their creators. Further investigation revealed that only the quantity of text annotations among all other variables can significantly predict students' learning achievement. This finding may suggest that text annotations play more important roles to learning achievement than other variables, like homework. The reason is because text annotations are created by learners actively on voluntary base whereas homework is usually assigned by the teachers. Based on our findings, we suggest that teachers may consider incorporating learning activities that can foster metacognitive development into the learning process, like making annotations, solving homework and reviewing them, whereas peer learning should be encouraged only for reviewing the homework solutions of their peers with good learning achievement. 相似文献
18.
This article examines formative interventions as we understand them in cultural-historical activity theory and reflects on key differences between this intervention research tradition and design-based research as it is conceived in the learning sciences tradition. Three projects, including 2 Change Laboratories, are analyzed with the help of conceptual lenses derived from basic epistemological principles for intervention research in activity theory. In all 3 interventions, learners expansively transformed the object of their activity. The Change Laboratory cases, however, show that this learning process included productive deviations from the researchers’ instructional intentions, leading to significant outcomes, both practical and theoretical, that were not anticipated by the interventionists. Together these cases illustrate that an activity-theoretical formative intervention approach differs from design-based research in the following ways: (a) formative interventions are based on design done by the learners; (b) the collective design effort is seen as part of an expansive learning process including participatory analyses and implementation phases; (c) rather than aiming at transferable and scalable solutions, formative interventions aim at generative solutions developing over lengthy periods of time both in the researched activities and in the research community. 相似文献
19.
本文针对作文教学中存在的现实性问题,提出了“构建开放的、活泼的、动态的学生全程自主作文训练体式”、“进行听说读写一体化训练”、“凸出思维训练”、“关注发展等级”、“把评改权还给学生”等解决方案,对提高作文教学效率有一定的参考价值。 相似文献
20.
在分析了简单遗传算法求解带约束的多峰值函数优化中存在的问题的基础上,提出了利用小生境技术和多父体杂交的演化算法,对复杂的多峰值函数优化问题进行了测试,证实该算法能够快速求出多峰函数的所有全局最优解,而且搜索效率高,达到了令人满意的效果. 相似文献