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为解决二维无线传感器网络随机部署产生的节点分布不均、覆盖率低的问题,提出一种融合元启发式算法的网络部署方案。该方案以节点部署空间作为约束条件、网络覆盖范围作为目标函数对二维网络覆盖模型进行数学建模。针对白骨顶鸡优化算法全局探索能力不强且在迭代后期容易陷入局部最优的缺点,该方案引入复合突变策略和随机反向策略对原算法进行改进。在二维网络覆盖模型进行的仿真测试结果表明:部署改进白骨顶鸡优化算法的二维无线传感器网络不仅网络覆盖率更高,节点也更加均匀,验证了改进白骨顶鸡优化算法解决节点部署问题的有效性和实用性。 相似文献
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创设问题情境能帮助学生进行深入细致的观察分析,从而培养学生的观察能力与直觉思维能力;更能帮助学生针对所观察的数学情境提出相关的数学问题,培养学生的提出问题能力与抽象思维能力。现通过分析一则案例,提出面对易境时,凭数学直觉发现问题、提出问题;面对困境时,凭元认知分析问题、解决问题;面对胜境时,凭反思创新解法、升华问题。从而强调在重视创设问题情境的同时,更要重视常规问题情境的发现和挖掘。 相似文献
3.
传统的会计方法已经难以满足现代制造模式的需要，而作业成本法可以克服传统成本系统的局限性．本把作业成本法和工作流技术相结合，构建了一个支持作业成本法的工作流元模型．中首先介绍了一个作业成本法的概念及其概念模型，其次介绍了一个工作流元模型PPROCE，通过为其添加作业成本法的思想，建立了一个支持作业成本法的成本子模型．最后，给出了一个基于该工作流元模型的企业过程仿真建模工具．通过以上工作，可以系统地对企业过程进行建模和仿真，并可以分析成本在内的各个方面信息． 相似文献
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Nicholas Maxwell 《Teaching in Higher Education》2013,18(1):129-134
Two great problems of learning confront humanity: learning about the universe, and learning how to live wisely. The first problem was solved with the creation of modern science, but the second problem has not yet been solved. This combination puts humanity into a situation of unprecedented danger. In order to solve the problem we need to learn from our solution to the first problem. This requires that we bring about a revolution in the overall aims and methods of academic inquiry, so that it takes up its proper task of promoting wisdom. 相似文献
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Dominic Voyer 《International Journal of Science and Mathematics Education》2011,9(5):1073-1092
Many factors influence a student’s performance in word (or textbook) problem solving in class. Among them is the comprehension
process the pupils construct during their attempt to solve the problem. The comprehension process may include some less formal
representations, based on pupils’ real-world knowledge, which support the construction of a ‘situation model’. In this study,
we examine some factors related to the pupil or to the word problem itself, which may influence the comprehension process,
and we assess the effects of the situation model on pupils’ problem solving performance. The sample is composed of 750 pupils
of grade 6 elementary school. They were selected from 35 classes in 17 Francophone schools located in the province of Quebec,
Canada. For this study, 3 arithmetic problems were developed. Each problem was written in 4 different versions, to allow the
manipulation of the type of information included in the problem statement. Each pupil was asked to solve 3 problems of the
same version and to complete a task that allowed us to evaluate the construction of a situation model. Our results show that
pupils with weaker arithmetic skills construct different representations, based on the information presented in the problem.
Also, pupils who give greater importance to situational information in a problem have greater success in solving the problem.
The situation model influences pupils’ problem solving performance, but this influence depends on the type of information
included in the problem statement, as well as on the arithmetic skills of each individual pupil. 相似文献
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《中学数学教学参考》2008,(1):126-127
在解析几何中,人们建立了几何与代数之间的对应关系．几何中的基本概念及定理可以代数地描述和证明;代数中的基本概念和过程可以几何地解释．当一个几何问题看起来比较困难时,可考虑相应的代数问题．如果在这个特殊情况下,代数工具更加有效的话,我们就先代数地解决这个问题,而后把结果翻译成几何语言．但常常是沿相反的方向进行的． 相似文献
9.
论道德选择中的权变问题 总被引：1，自引：0，他引：1
贾新奇 《北京师范大学学报(社会科学版)》2004,(2):82-87
权变是人们在进行道德选择时需要时常面对的一个复杂问题 ,所以正确理解和对待权变 ,是人们进行正确的道德实践的一个重要前提。中西思想史上 ,关于权变问题曾出现过多种不同的理论。所谓权变 ,就是人们在特殊情境中 ,为了避免不必要的利益损失 ,或者为了维护更大的道德价值 ,对自己所认可的某项道德准则所采取的背离行为。权变具有多方面的特征。权变发生的情境可概括为非必要代价情境和准则冲突情境两种 ,相应地 ,权变也可分为非必要代价型权变和准则冲突型权变两种。对待权变 ,既要承认其必要性、合理性 ,也要有批判和审慎的态度。 相似文献
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迷宫问题是《数据结构》中是作为栈的典型应用举例，且迷宫是以二维数组来存储的，表面上看似乎迷宫问题是一种特殊问题的解决方法，其实迷宫问题是一种特殊形式的图的问题。因此，迷宫问题总是可以转化为图的问题来解决的。讨论如何将迷宫问题转化成图的问题，以及如何利用图的算法来解决迷宫问题。 相似文献
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解决高校扩招后教学质量问题的若干思考 总被引：5，自引：0，他引：5
要解决高校扩招后的教学质量问题，应该采取调整高等教育的层次结构，按照学校定位办校提高认识、统一认识；加强师资队伍建设；增加投入、改善办学硬件条件；深化教学改革、强化教学质量管理完善高等教育法规等对策。 相似文献
12.
刘敏 《科学技术哲学研究》2020,37(2):114-118
以“问题”观为视角重读杜威,发现杜威科学观具有重要的问题学启示与价值。杜威科学观的根基是实践主义,按照杜威,科学问题是实践中特殊情境的产物,探究的任务是使问题更清晰和明确;理解科学的价值关键是理解价值的生成。杜威科学观对问题学的启示是:科学问题的生成具有地方性(local)特质,而科学问题的提出与解答,决定于问题生成的情境及提问主体的实践判断。从问题(problem)意识到问题(question)呈现具有重要意义,恰当地表述问题是有效解决问题的必要条件;价值不是我们对既成标准的被动接受,科学问题的价值负载表现为问题的表述和解答均受文化塑形(shape)与价值观的影响。 相似文献
13.
图卷积网络由于能够直接处理图结构数据的优点而受到广泛研究。当前的多数图卷积网络是基于图信号的平滑性(低频信息),且不能根据各节点适合的接受域生成对应的节点嵌入,随着网络层数的增加,易出现图卷积网络特有的过平滑问题而导致性能下降。为此,提出了基于自适应频率和动态节点嵌入的图卷积网络模型(adaptive frequency and dynamic node embedding based graph convolutional network, FDGCN)。FDGCN模型能够自适应聚合不同频率的信息,同时利用每层网络的输出,平衡每个节点来自全局和局部领域的信息,动态地调节节点嵌入。通过在4个公共数据集上进行实验,对比了6个现有模型,证明了FDGCN模型的有效性。 相似文献
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《学习科学杂志》2013,22(1):63-103
Epistemic dialogues, involving explanation and argumentation, have been recognized as potential vehicles for conceptual understanding. Although the role of dialogue in learning has received much attention, the problem of creating situations in which students engage in epistemic dialogue has only begun to be addressed. This article highlights the set of factors that must be taken into account in designing a computer-supported collaborative learning situation that encourages students to discuss scientific notions. These factors include the choice of the domain issue, the activities proposed to students, and the role of technology. We describe the design of CONNECT, an integrated environment and task sequence for the collaborative confrontation, negotiation, and construction of text. Results are then presented from a study in which students individually wrote an interpretation of a sound phenomenon, were matched in dyads so as to maximize semantic differences between their texts, and then collaboratively discussed and wrote common texts across the network using CONNECT. We show how careful engineering of the CONNECT environment favors the occurrence of epistemic dialogue and creates opportunities for conceptual understanding. The discussion centers on why these opportunities might be missed, as well as on the conditions required for students to exploit them. 相似文献
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网络财务面临的问题及对策 总被引：2，自引：0，他引：2
随着网络时代的到来,网络财务也随之逐步发展起来。网络财务在其发展过程中遇到了譬如网络安全、财务核算手段变革、人才培养等问题。面对问题,企业应根据现实情况,寻求策略,以期解决网络财务在发展中的种种阻碍,进而促使这一新兴事物不断完善,发挥它的潜力和优势。 相似文献
16.
We examine classroom situations which allow the learning of rules of mathematical reasoning. Drawing on an epistemological analysis and G. Brousseau's theory of situations, we define a priori theoretical characteristics which such situations must possess. We then use this analysis, and hypotheses about the cognitive functioning of pupils of this age, to establish learning situations for the rule of the excluded middle, and for the use of the figure in geometry. We report the results of experimentation with two of thses situations and show that, through the study of a mathematical problem, debate about these rules can be generated amongst students aged twelve to thirteen. We explain why, in our opinion, for epistemological reasons linked to the two particular rules concerned, it is necessary for the teacher to conclude the debate, and we examine our cognitive hypotheses against the actual results of experimentation. 相似文献
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Hamid Sadeghi 《Interactive Learning Environments》2016,24(3):382-395
Group formation task as a starting point for computer-supported collaborative learning plays a key role in achieving pedagogical goals. Various approaches have been reported in the literature to address this problem, but none have offered an optimal solution. In this research, an online learning environment was modeled as a weighted undirected complete graph in which each learner was implied as a node and the relationship between them was denoted as a weighted arc. The weight of each link indicated the similarity degree between the corresponding individuals. The similarity between two students was measured as the mean of their absolute interest levels. The graph was also represented through a symmetric adjacency matrix. Then, a novel binary integer programming formulation was proposed to model the group formation problem and optimally assign each learner to the most appropriate group. The method was utilized to divide an online class of 32 learners into 8 groups of size 4. Findings indicated that the suggested model was successful in optimally solving the problem in 20.53 seconds, on average. The performance of the method was also compared with a modified version of K-means clustering algorithm. Although, the running time of the suggested technique was not as good as the clustering algorithm, it generated better outcomes in theory and in practice. 相似文献
18.
连续型Hopfield神经网络(CHNN)可用于优化计算,但其会遭遇较复杂的参数辨识问题.为了较好地解决这一问题,将擅长全局搜索的蚁群-粒子群混合算法用于对系统参数的最优化选取.再将此混合算法与CHNN有机结合,更好地解决参数辨识问题,且能有效避免CHNN在应用过程中陷入局部最优解.最后,将理论结果应用于求解TSP问题来验证其有效性. 相似文献
19.
为了解决汽车白车身焊接机器人路径规划不合理的问题,将路径规划问题抽象为TSP模型.本文从图论的角度出发,采用Christofides算法,编写相应的MATLAB程序对一个具体的实例进行仿真.该算法可以有效地解决焊接机器人路径规划问题. 相似文献
20.
The present study takes an interdisciplinary mathematics–physics approach to the acquisition of the concept of angle by children in Grades 3–5. This paper first presents the theoretical framework we developed, then we analyse the concept of angle and the difficulties pupils have with it. Finally, we report three experimental physics‐based teaching sequences tested in three classrooms. We showed that at the end of each teaching sequence the pupils had a good grasp of the concept of angle, they had truly appropriated the physics knowledge at play, and many pupils are enable to successfully grasp new physics situations in which the angle plays a highly meaningful role. Using a physics framework to introduce angles in problem situations is then pertinent: by interrelating different spaces, pupils were able to acquire skills in the domains of mathematics, physics, and modelling. In conclusion, we discuss the respective merits of each problem situation proposed. 相似文献