• Journal of Korean Elementary Science Education
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• v.27 no.4
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• pp.446-454
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• 2008

The purpose of this study was to examined the effects of different grouping according to the levels of students' achievement in science cooperative learning on students' science academic achievements, science-related attitudes, perceptions of science learning environment and self-efficacies. The results of this study can be summarized as following. First, the homogeneous grouping was more effective than the heterogeneous grouping in improving the science academic achievements of high academic ability students. Second, the homogeneous grouping was more effective than the heterogeneous grouping in improving the science-related attitude of students, especially for low academic ability students. Third, both the homogeneous grouping and the heterogeneous grouping improved the perceptions of science learning environment of students. For low academic ability students, the homogeneous grouping was more effective. Fourth, the homogeneous grouping was more effective than the heterogeneous grouping in improving self-efficacies of students, especially for middle and low academic ability students.

• English Language & Literature Teaching
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• v.12 no.4
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• pp.185-210
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• 2006

This study has two purposes. First, it aims to suggest an appropriate approach to English writing education for Korean high school students in a cooperative learning situation. It also aims to suggest what type of learner grouping, either homogeneous or heterogeneous, is appropriate by comparing the learners' writing abilities and the changes of their affective factors after being exposed to cooperative EFL writing instruction. Two homogeneous classes were selected and instructed to write in English for 11 weeks. One was composed of homogeneous small groups based on the students' writing scores, and the other was composed of heterogeneous small groups, again based on the students' writing scores. The results showed that the improvement between the two class types was quite different across different proficiency levels. For example, although there is little difference between the homogeneous and the heterogeneous classes of low and intermediate-level learners in writing ability improvement, high-level students showed a significant difference between the classes. In addition, it was found that class participation correlated significantly to writing ability improvement. Cooperative learning was proved to be an effective writing instructional approach to encourage learners' interest and increase their self-confidence; however, the results did not show any significant differences in learners' affective domain between the homogeneous and the heterogeneous classes. Similarly, the learners' grouping preference was not affected by the grouping method.

• Journal of Communications and Networks
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• v.13 no.4
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• pp.360-366
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• 2011

In this paper, we investigate the problem of power allocation in a heterogeneous network that is composed of a pair of cognitive users (CUs) and an infrastructure-based primary network. Since CUs have only limited effective spectrum-sensing ability and primary users (PUs) are not active all the time in all locations and licensed bands, we set up a new multi-area model to characterize the heterogeneous network. A novel combined interference-avoidance policy corresponding to different PU-appearance situations is introduced to protect the primary network from unacceptable disturbance and to increase the spectrum secondary-reuse efficiency. We use dual decomposition to transform the original power allocation problem into a two-layer optimization problem. We propose a low-complexity joint power-optimizing method to maximize the transmission rate between CUs, taking into account both the individual power-transmission constraints and the combined interference power constraint of the PUs. Numerical results show that for various values of the system parameters, the proposed joint optimization method with combined PU protection is significantly better than the opportunistic spectrum access mode and other heuristic approaches.

• Journal of Korean Elementary Science Education
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• v.38 no.1
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• pp.1-15
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• 2019

This study aimed to identify the effects of students' empathy ability on group creativity, when elementary school students perform scientific activity designed to express group creativity. A total of 12 elementary students from a fifth-grade science club participated in this study. A pretest to examine the students' empathic ability was performed to classify them into three groups: A group with high, low and heterogeneous empathic members. The linguistic interaction was analyzed to determine the process of group creativity manifestation; the results were classified into 'metacognitive', 'cognitive', and 'social-communicative'. As a result, groups with high empathic ability showed more frequent interaction in monitoring, planning, and divergent thinking. On the other hand, in the case of the group with low level of empathy, it was confirmed that there are many interactions related to regulation, convergent thinking, and noncohesive prosocial interaction. Also, in the case of heterogeneous group with empathy ability, group creativity utterance on all sides was relatively higher than other groups. As a result of this study, we could confirm the influence of empathy as a strategy to help the group creativity and discuss the educational implications.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.4
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• pp.497-516
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• 2018

The purpose of this study is to compare the process of mathematical modeling in mathematical modeling class according to group organization, and to investigate whether it shows improvement in mathematical reasoning ability. A total of 24 classes with 3 mathematical modeling activities were designed to investigate the research problem. The result of this study showed that the heterogeneous groups performed better than the homogeneous groups in terms of both the performance ability of mathematical modeling and mathematical reasoning ability. This study implies that, with respect to group design for applying mathematical modeling in teaching mathematics, heterogeneous group design would be more efficient than homogeneous group design.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.102-107
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• 2011

In this paper we present cooperation of heterogeneous robot team, composed of a wheeled robot and a helicopter for localization and map building. This heterogeneous robot team can successfully fulfill task by combining the abilities of both robots than single robot because wheeled robot and helicopter have complementing ability. The scenario describes a tightly cooperative task, where the wheeled robot move carrying the helicopter and detect obstacles, if there are obstacles, helicopter take off for map building and land, then robot team move destination avoiding obstacles. We present PID controller for position control of helicopter and transformation algorithm to global coordinate from image pixel coordinate. Experimental result show that the proposed method is valid.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.143-151
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• 2009

In this paper, we define Achieved Goodput(AG), Achieved Goodput Index(AGI) and Normalized Achieved Goodput Index(NAGI) in order to evaluate TCP schemes over heterogeneous wireless networks. These metrics contain a concept of achievement, the ability of accomplishing an objective in a given network situation unlike performance metrics commonly used to evaluate TCP schemes.

• Journal of Labour Economics
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• v.40 no.4
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• pp.91-114
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• 2017

This paper shows that when children's ability is heterogeneous, a parent's choices about educational expenditures and fertility follow a pooling equilibrium or a separating equilibrium. Which of the two equilibria will prevail depends on the probability of getting a high-ability child as well as productivity differentials in producing children's adult human capital. Adopting the model of Acemoglu's (1999), this paper presents that the outcome of the pooling choice in the pooling regime and the outcome of the separating choice in the separating regime make the growth rate of human capital higher than otherwise. In addition, as the probability of a high-ability child increases, the growth rate of human capital in the separating equilibrium exceeds that in the pooling equilibrium.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.163-171
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• 2013

Recently, the requirement of processing High Definition (HD) video or 3D application on low, mobile devices has been expanded and content data has been increased as well. It is becoming a major issue in Cloud computing where a Virtual Desktop Infrastructure (VDI) Service needs efficient data processing ability to provide Quality of Experience (QoE) in Cloud computing. In this paper, we propose three kind of Thick-Thin VDI Service which can share and delegate VDI service based on Thick Client using CPU and GPU. Furthermore, we propose and discuss the VDI Service Optimization Method in mixed CPU and GPU Heterogeneous Environment using CPU Parallel Processing OpenMP and GPU Parallel Processing CUDA.

• Coupled systems mechanics
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• v.11 no.2
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• pp.167-198
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• 2022

In this paper we deal with classical instability problems of heterogeneous Euler beam under conservative loading. It is chosen as the model problem to systematically present several possible solution methods from simplest deterministic to more complex stochastic approach, both of which that can handle more complex engineering problems. We first present classical analytic solution along with rigorous definition of the classical Euler buckling problem starting from homogeneous beam with either simplified linearized theory or the most general geometrically exact beam theory. We then present the numerical solution to this problem by using reduced model constructed by discrete approximation based upon the weak form of the instability problem featuring von Karman (virtual) strain combined with the finite element method. We explain how such numerical approach can easily be adapted to solving instability problems much more complex than classical Euler's beam and in particular for heterogeneous beam, where analytic solution is not readily available. We finally present the stochastic approach making use of the Duffing oscillator, as the corresponding reduced model for heterogeneous Euler's beam within the dynamics framework. We show that such an approach allows computing probability density function quantifying all possible solutions to this instability problem. We conclude that increased computational cost of the stochastic framework is more than compensated by its ability to take into account beam material heterogeneities described in terms of fast oscillating stochastic process, which is typical of time evolution of internal variables describing plasticity and damage.