• Korea Trade Review
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• v.44 no.5
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• pp.143-159
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• 2019

This study explores the relationship between outward foreign direct investment (FDI) and innovation in 61 industries of Korea between 1999 and 2016. In order to mitigate the endogeneity problem due to potential reverse causality between FDI and innovation, we use the GMM (generalized method of moments). Our results are as follows. First, FDI has a positive effect on innovation. A possible explanation is that through FDI, multinational companies may assimilate host countries' technologies and knowledge by learning, and then recreating new technologies. Furthermore, this positive effect appears greater, as industrial competition becomes fiercer. This result provides empirical evidence that by recreating technology and knowledge learned through FDI with their own intangible assets, such as patents, they may gain a competitive edge over competitors. Second, this study confirms the greater positive effects of FDI in developed countries, as well as countries with higher technology levels. Finally, strategic asset seeking FDI has the greatest positive impact on innovation in Korean industries. In summary, our findings provide empirical evidence that Korean multinationals can learn technology and knowledge of host countries through FDI to secure a competitive edge in the Korean market.

• Structural Engineering and Mechanics
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• v.83 no.3
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• pp.353-361
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• 2022

Linear Elastic Fracture Mechanics (LEFM) has been developed by applying stress analysis to determine the stress intensity factor (SIF, K). The finite element method (FEM) is widely used as a standard tool for evaluating the SIF for various crack configurations. The prediction accuracy can be achieved by applying an adaptive Delaunay triangulation combined with a FEM. The solution can be solved using either direct or iterative solvers. This work adopts the element-by-element preconditioned conjugate gradient (EBE-PCG) iterative solver into an adaptive FEM to solve the solution to heal problem size constraints that exist when direct solution techniques are applied. It can avoid the formation of a global stiffness matrix of a finite element model. Several numerical experiments reveal that the present method is simple, fast, and efficient compared to conventional sparse direct solvers. The optimum convergence criterion for two-dimensional LEFM analysis is studied. In this paper, four sample problems of a two-edge cracked plate, a center cracked plate, a single-edge cracked plate, and a compact tension specimen is used to evaluate the accuracy of the prediction of the SIF values. Finally, the efficiency of the present iterative solver is summarized by comparing the computational time for all cases.

• Journal of the Korean Society of Visualization
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• v.22 no.1
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• pp.79-84
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• 2024

As microchips' degree of integration is getting higher, its cooling problem becomes important more than ever. One of the promising methods is using fractal microchannel heat sink by mimicking nature's Murray networks. However, most of the related works have been progressed only by numerical analysis. Perhaps such lack of direct experimental studies is due to the technical difficulty of the temperature and heat flux measurement in complex geometric channels. Here, we demonstrate the direct visualization of in situ temperature profile in a fractal microchannel heat sink. By using the temperature-sensitive fluorescent dye and a transparent Polydimethylsiloxane window, we can map temperature profiles in silicon-based fractal heat sinks with various fractal scale factors (a=1.5-3.5). Then, heat transfer rates and pressure drops under a fixed flow rate were estimated to optimize hydrodynamic and thermal characteristics. Through this experiment, we found out that the optimal factor is a=1.75, given that the differences in heat transfer among the devices are marginal when compared to the variances in pumping power. This work is expected to contribute to the development of high-performance, high-efficiency thermal management systems required in various industrial fields.

• Education of Primary School Mathematics
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• v.15 no.2
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• pp.107-134
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• 2012

The purpose of this study is to investigate the effectiveness of two teaching methods of word problems, one based on mathematical modeling learning(ML) and the other on traditional learning(TL). Additionally, the influence of mathematical modeling learning in word problem solving behavior, application ability of real world experiences in word problem solving and the beliefs of word problem solving will be examined. The results of this study were as follows: First, as to word problem solving behavior, there was a significant difference between the two groups. This mean that the ML was effective for word problem solving behavior. Second, all of the students in the ML group and the TL group had a strong tendency to exclude real world knowledge and sense-making when solving word problems during the pre-test. but A significant difference appeared between the two groups during post-test. classroom culture improvement efforts. Third, mathematical modeling learning(ML) was effective for improvement of traditional beliefs about word problems. Fourth, mathematical modeling learning(ML) exerted more influence on mathematically strong and average students and a positive effect to mathematically weak students. High and average-level students tended to benefit from mathematical modeling learning(ML) more than their low-level peers. This difference was caused by less involvement from low-level students in group assignments and whole-class discussions. While using the mathematical modeling learning method, elementary students were able to build various models about problem situations, justify, and elaborate models by discussions and comparisons from each other. This proves that elementary students could participate in mathematical modeling activities via word problems, it results form the use of more authentic tasks, small group activities and whole-class discussions, exclusion of teacher's direct intervention, and classroom culture improvement efforts. The conclusions drawn from the results obtained in this study are as follows: First, mathematical modeling learning(ML) can become an effective method, guiding word problem solving behavior from the direct translation approach(DTA) based on numbers and key words without understanding about problem situations to the meaningful based approach(MBA) building rich models for problem situations. Second, mathematical modeling learning(ML) will contribute attitudes considering real world situations in solving word problems. Mathematical modeling activities for word problems can help elementary students to understand relations between word problems and the real world. It will be also help them to develop the ability to look at the real world mathematically. Third, mathematical modeling learning(ML) will contribute to the development of positive beliefs for mathematics and word problem solving. Word problem teaching focused on just mathematical operations can't develop proper beliefs for mathematics and word problem solving. Mathematical modeling learning(ML) for word problems provide elementary students the opportunity to understand the real world mathematically, and it increases students' modeling abilities. Futhermore, it is a very useful method of reforming the current problems of word problem teaching and learning. Therefore, word problems in school mathematics should be replaced by more authentic ones and modeling activities should be introduced early in elementary school eduction, which would help change the perceptions about word problem teaching.

• Journal of Korea Technology Innovation Society
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• v.16 no.4
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• pp.913-936
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• 2013

As diversity has getting its significance, recent research on diversity has moved the focus from direct effects of diversity on performance to moderating effects between the two. In this paper, I analyzed the moderating effects of the innovative problem solving style and three types of interdependence (i.e., task, goal and outcome) on the relationship between diversity and performance. Empirical results using 75 project teams of R&D institute showed that the innovative problem solving style positively strengthened the effect of diversity on performance. All three types of interdependence also amplified the relationship between diversity and performance. I addressed theoretical and practical implications, and future research directions.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.2
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• pp.157-165
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• 2007

Purpose: The purpose of this study was to investigate the plan to introduce a practical skills test as part of the national examination for nursing licensure. Method: The delphi method was used. The first set of data was collected by open questionnaire from universities and hospitals nationally. The second and third were collected by structured questionnaire. Results: The biggest problem for clinical Practice in nursing education was reported as the lack of opportunities for direct nursing practice. The biggest performance problem in job duties for novice nurses was reported as the lack of integrated problem solving skills in a clinical situation. The biggest problem with the current national examination was reported as the use memorizing solutions to test questions. It was suggested that the best plan to resolve problems with the national examination would be to develop test questions representative of the clinical setting and increase personnel in clinical education. About the introduction of a practical skills test as part of the national examination, 56.9% were in agreement and 38.5% disagreed. Conclusion: The current national examination has many problems when it comes to testing clinical competency. So, a practical skills test must be deferred to a future time. There are also many difficulties in presenting a real situation, therefore further research is needed in preparation for the introduction of a practical skills test.

• Journal of the Korean Home Economics Association
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• v.49 no.7
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• pp.67-80
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• 2011

This study investigated a path model in which men's and women's communication behavior escalating marital conflict (CBEMC) may be influenced directly and indirectly, via negative interpretations of their spouse, by their spouse's problem behavior, the couple's turning toward bids, and dyadic perspective-taking. Self-report data were collected from 498 married men and women who were living in Busan, Korea. Multiple-group analysis revealed that the path model was not equivalent for men and women. Their couple's turning toward bids and dyadic perspective-taking for men, and their spouse's problem behavior and dyadic perspective-taking for women, had direct effects on CBEMC. Further, their spouse's problem behavior and the couple's turning toward bids had indirect effects on CBEMC through negative interpretations in both men and women. The indirect effect of dyadic perspective-taking on CBEMC was significant only for men. Finally, considering total effects, dyadic perspective-taking was the strongest predictor of CBEMC for both genders.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.2028-2041
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• 2019

Compressed sensing (CS) is a new theory. With regard to the sparse signal, an exact reconstruction can be obtained with sufficient CS measurements. Nevertheless, in practical applications, the transform coefficients of many signals usually have weak sparsity and suffer from a variety of noise disturbances. What's worse, most existing classical algorithms are not able to effectively solve this issue. So we proposed an efficient algorithm based on smoothed ${\ell}_0$ norm for sparse signal reconstruction. The direct ${\ell}_0$ norm problem is NP hard, but it is unrealistic to directly solve the ${\ell}_0$ norm problem for the reconstruction of the sparse signal. To select a suitable sequence of smoothed function and solve the ${\ell}_0$ norm optimization problem effectively, we come up with a generalized approximate function model as the objective function to calculate the original signal. The proposed model preserves sharper edges, which is better than any other existing norm based algorithm. As a result, following this model, extensive simulations show that the proposed algorithm is superior to the similar algorithms used for solving the same problem.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.244-251
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• 2005

In this paper, we study the problem of stabilizing a general nonlinear control system by means of gradient descent control method which is a dynamic feedback control law. In this method, the general nonlinear control system can be considered as an affine nonlinear control systems. Then by using Sontag's formula we investigate the stability (asymptotic) of the general nonlinear control system.

• ETRI Journal
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• v.26 no.6
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• pp.545-554
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• 2004

In this paper, we propose an efficient design method for area optimization in a digital filter. The conventional methods to reduce the number of adders in a filter have the problem of a long critical path delay caused by the deep logic depth of the filter due to adder sharing. Furthermore, there is such a disadvantage that they use the transposed direct form (TDF) filter which needs more registers than those of the direct form (DF) filter. In this paper, we present a hybrid structure of a TDF and DF based on the flattened coefficients method so that it can reduce the number of flip-flops and full-adders without additional critical path delay. We also propose a resource sharing method and sharing-pattern searching algorithm to reduce the number of adders without deepening the logic depth. Simulation results show that the proposed structure can save the number of adders and registers by 22 and 26%, respectively, compared to the best one used in the past.