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1.
Pongsakdi  Nonmanut  Kajamies  Anu  Veermans  Koen  Lertola  Kalle  Vauras  Marja  Lehtinen  Erno 《ZDM》2020,52(1):33-44
ZDM – Mathematics Education - In this study we investigated word-problem (WP) item characteristics, individual differences in text comprehension and arithmetic skills, and their relations to...  相似文献   

2.
We conducted a 7-month video-based study in two sixth-grade classrooms focusing on teachers’ metacognitive and heuristic approaches to problem solving. All problem-solving lessons were analysed regarding the extent to which teachers implemented a metacognitive model and addressed a set of eight heuristics. We observed clear differences between both teachers’ instructional approaches. Besides, we examined teachers’ and students’ beliefs about the degree to which metacognitive and heuristic skills were addressed in their classrooms and observed that participants’ beliefs were overall in line with our observations of teachers’ instructional approaches. In addition, we investigated how students’ problem-solving skills developed as a result of teachers’ instructional approaches. A positive relationship between students’ spontaneous application of heuristics to solve non-routine word problems and teachers’ references to these skills in their problem-solving lessons was found. However, this increase in the application of heuristics did not result in students’ better performance on these non-routine word problems.  相似文献   

3.
We propose a modification of B. N. Pshenichnyi's method of linearization for solving mathematical programming problems on a simple set of parallelepiped type. We study in detail the computational aspects and the efficiency of the approach in question. Two tables. Bibliography: 3 titles.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 30, 1989, pp. 24–28.  相似文献   

4.
Mathematical word problems used in Verschaffel et al.??s (Learning and Instruction 7:339?C359, 1994) study were applied in several follow-up studies. The goal of the present study was to replicate and extend the results of this line of research in a large sample of Hungarian students using an alternative set of data-gathering and data-analysis techniques. 4,037 students forming a nationwide representative sample of the Hungarian fifth-grade student population (aged 10?C11) completed the test. The test contained five word problems from the list of 10 P(??problematic)-items from Verschaffel et al.??s test. In contrast to all previous research in this domain, we used a multiple-choice format, where three options were given for each task: (a) routine-based, non-realistic answer, (b) numerical response that does take into account realistic considerations, (c) a realistic solution stating that the task cannot be solved. The hypotheses of this study were: (1) Students?? responses will confirm previous results, i.e. upper elementary school students prefer to respond to P-items by means of the routine-based answer; (2) Most students will demonstrate a more or less consistent preference for a given answer type (a, b or c) over problems; (3) Students?? school math marks will have low correlation indices with students?? achievement on these word problems. Our results confirm student??s overall tendency to follow non-realistic approaches when doing school word problem solving. The tendency even holds when confronting students with various kinds of realistic answers. Our results show that students demonstrate response patterns over problems, and that the correlation with math school performance is significant but small.  相似文献   

5.
The most effective treatment for kidney failure that is currently known is transplantation. However, the supply of kidneys from cadaveric donors does not meet the fast-growing demand and the kidney from a willing living donor (genetically or emotionally relative of the patient) is often not suitable for immunological reasons. Therefore in several countries attempts have started to organize exchanges of kidneys between incompatible patient-donor pairs. On the theoretical side, game-theoretical models have been proposed to analyze various optimality criteria for such exchanges and various search schemes have been tested. One possibility to model patients’ preferences is to take into account in the first step the suitability of the donated kidney and in the second step the length of the obtained cycle of exchanges. Although the core of such a cooperative game is always nonempty and one solution can be found by the famous Top Trading Cycles algorithm, in this paper we show that many questions concerning the structure of the core are difficult to answer.  相似文献   

6.
Hao  Yue  Yang  Ai-Li  Wu  Yu-Jiang 《Numerical Algorithms》2020,83(3):1205-1221
Numerical Algorithms - For the singular, non-Hermitian, and positive semi-definite system of linear equations Ax = b, we introduce a kind of preconditioners for the preconditioned Hermitian and...  相似文献   

7.
In the present paper, we consider a quasilinear elliptic equation in ℝ N with a parameter whose values lie in a neighborhood of an eigenvalue of the linear problem. To prove the existence of a nontrivial solution, we use a modification of the conditional mountain pass method. The difficulties related to the lack of compactness of the Sobolev operator in the case of an unbounded domain are eliminated with the use of the Lions concentration-compactness method.  相似文献   

8.
Collaborative research, defined as research involving actors participating in the problem situation under study, has an important role in operational research, strategic management and systems thinking. In a recent study, we found that a strong organizational focus incorporated into many soft operational research (OR) approaches is inadequate for studying societal problem situations, which are fragmented and have no clear boundary. Specifically, we failed to find a process of identifying individuals that is capable of representing the perspectives of actors and sufficient for research into societal problem situations. We found no clear terminology accounting for ontological differences between actors, individuals representing them and conceptual representations of acting entities. In response to this gap in the literature, we propose terminology that differentiates among actors (individuals or collective entities in the real world), experts (individuals capable of representing the perspective of an actor) and agents (ideal-typical representations of actors). Based on this terminology, we propose an iterative method to guide the assembly of an expert group to undertake collaborative research into societal problem situations. To demonstrate the application of our method, we present selected insights from our study in an electronic supplement.  相似文献   

9.
Global brands emerging from the world of sports are becoming commonplace, and firms invest in the realm of sports, usually through sponsorship initiatives, to get a link with these global brands. Over and above just a mere business link, what if a company makes a personal commitment to get into the core of a renowned, celebrated sports team? This article provides managers with a procedure to analyze, in a weekly basis, how valuable this type of decision is. A conceptual model shows that the personal involvement of a firm’s figurehead in a first-class sports club can impact positively on firm value if the person is doing well in the task s/he is entrusted with by the club. The empirical application to the soccer club Real Madrid, over 1,409 days and 215 matches, finds that the club’s performance on the field has a significant impact on the economic returns of its president’s company, with asymmetrical effects on firm value in a “loss aversion” pattern, that is, lost matches have a greater effect on firm value than games won.  相似文献   

10.
This study analyzes Mixed Integer Linear Program (MILP) proposed by G. Kannan, P. Sasikumar M. Devika, (2010) in their paper titled ‘A genetic algorithm approach for solving a closed loop supply chain model: A case of battery recycling’, Applied Mathematical Modelling, (34, 655–670). The model in Kannan et al. (2010) is found to be inadequate for the problem described. It is erroneous/infeasible in terms of constraints, objective and variables. In this work, we list down the flaws in the published work and propose modifications to rectify the flaws. The revised model is presented and illustrated using hypothetical problems.  相似文献   

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