• 무역학회지
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• 제44권5호
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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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• 제83권3호
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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.

• 한국가시화정보학회지
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• 제22권1호
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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.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제15권2호
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• pp.107-134
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• 2012

수학적 모델링은 일반적으로 수학적인 방법으로 해석되고 이해되어야 하는 실제적인 문제 상황을 해결하기 위해 상황에 대한 적절한 수학적 모델을 구성하여 문제를 해결하는 일련의 과정이라고 할 수 있다. 문장제는 실제적인 측면과 형식적인 측면, 모두를 포함하고 있으므로 수학적 모델링 활동에 이상적인 도구가 될 수 있다. 이에 본 연구는 실세계의 맥락을 고려해야 하는 진정성있는 문장제를 바탕으로 한 수학적 모델링 학습이 문장제 해결 행동, 문장제 해결에서 실생활 경험을 활용하는 능력, 문장제에 대한 신념 등에 미치는 영향을 조사하였다. 연구 결과 문장제에 대한 수학적 모델링 학습은 직접번역 접근(DTA) 대신에 의미기반 접근(MBA)으로 문장제 해결 행동을 이끄는데 효과적이었으며, 문장제를 해결하는데 있어서 실생활 맥락을 고려하는 태도에 긍정적인 영향을 미쳤다. 또한 수학적 모델링 학습은 문장제에 대한 긍정적인 신념을 형성하는데 중요한 역할을 했음을 알 수 있었다. 이와 같은 연구 결과를 바탕으로 초등학교에서 문장제를 어떻게 다루어야 하는지에 대한 시사점을 살펴보았다.

• 기술혁신학회지
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• 제16권4호
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• pp.913-936
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• 2013

다양성의 중요성이 강조되면서 최근의 연구들은 다양성과 성과간의 직접효과에 대한 분석에서 상황적 요인의 효과를 분석하는 데 연구의 초점을 맞추고 있다. 본 연구에서는 다양성과 성과간의 관계를 보다 명확하게 파악하기 위해서 혁신적 문제해결 스타일과 상호의존성(과업, 목표, 결과)을 상황요인으로 제시한 후 이들 변수들의 조절효과를 분석하였다. R&D 연구소의 75개 프로젝트 팀을 대상으로 실증 분석한 결과 팀원들이 혁신적 문제해결 스타일을 가져갈 수록 다양성과 프로젝트 성과간의 긍정적 관계는 더욱 높아졌다. 또한 세 가지 유형의 상호의존성도 다양성과 프로젝트 성과간의 관계를 긍정적으로 조절하는 것으로 나타났다. 마지막으로 연구결과에 대한 시사점과 향후 연구방향에 대하여 논의하였다.

• 기본간호학회지
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• 제14권2호
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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.

• 대한가정학회지
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• 제49권7호
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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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• 제13권4호
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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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• 제3권2호
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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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• 제26권6호
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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.