• Journal of Magnetics
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• 제16권4호
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• pp.408-412
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• 2011

We investigated theoretically the magnetic field dependence of the quantum optical transition of qusi 2-Dimensional Landau splitting system, in GaN and ZnO. We apply the Quantum Transport theory (QTR) to the system in the confinement of electrons by square well confinement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). Through the analysis of this work, we found the increasing properties of the optical Quantum Transition Line Shapes(QTLSs) which show the absorption power and the Quantum Transition Line Widths(QTLWs) with the magnetic-field in GaN and ZnO. We also found that QTLW, ${\gamma}(B)_{total}$ of GaN < ${\gamma}(B)_{total}$ of ZnO in the magnetic field region B < 25 Tesla.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1993년도 학술논문발표회 논문집 제12권 1호
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• pp.190-194
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• 1993

In the ocean bubble layers play a significant role in the sound propagation as well as sound generation. Most of early works dealt with acoustic properties of the bubble layers with sharp flat boundaries. Bubble layers with sharp flat boundaries. Bubble layers with transition sublayers are more likely in the coean. In this paper a theory of sound propagation through plane bubble layers with transition sublayers at both borders was developed. It shows that the reflection and transmission coefficients depend on the thickness of transition sublayers. The theory with thicker transition sublayers shows weaker resonance properties of bubble layer. It gives better presentation for the peculiar behavior of the experimental data than that with sharp flat boundaries.

• 기술혁신연구
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• 제31권3호
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• pp.75-110
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• 2023

본 논문은 지난 세기 초부터 시작된 기술혁신이론의 진화를 분석한다. 기술혁신이론은 지난 세기 초 Joseph Schumpeter에 의해 시작되었으나 그의 이론은 주류경제학에 밀려 큰 각광을 받지 못하였다. 1960년대에 들어서 일부 신고전학파 경제학자들이 기술혁신이 경제발전에 미치는 영향을 분석하였다. 1970년대 초 사회경제의 발전에 있어서 기술혁신과 기업가 정신을 강조한 슘페터의 이론이 새로운 조명을 받았고, 이 시기 그의 이론을 추종하는 학자들을 '신슘페터주의자라'고 부른다. 이들은 1980년대에 들어 기술혁신의 창출, 활용, 확산에 있어서 한 국가 혁신자원의 총동원체제인 '국가혁신체제'의 개념을 창출하였고 이 개념은 빠르게 확산되어 실제로 전 세계적으로 혁신체제에 관한 많은 실증적 연구가 진행되었다. 2000년대 들어 유럽의 학자들을 중심으로 혁신체제의 지속가능한 체제로의 전환에 주안점을 두는 '전환이론'이 활발하게 진행되어 오고 있다. 그러나 우리나라는 이에 관한 연구가 부족하다는 점에서 이 새로운 기술혁신연구의 활성화가 매우 필요하다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.259-262
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• 2004

In most of the character recognition systems, the method of template matching or statistical method using hidden Markov model is used to extract and recognize feature shapes. In this paper, we used modified chain-code which has 8-directions but 4-codes, and made the chain-code of hand-written character, after that, converted it into transition chain-code by applying to HMM(Hidden Markov Model). The transition chain code by HMM is analyzed as signal flow graph by Mason's theory which is generally used to calculate forward gain at automatic control system. If the specific forward gain and feedback gain is properly set, the forward gain of transition chain-code using Mason's theory can be distinguished depending on each object for recognition. This data of the gain is reorganized as tree structure, hence making it possible to distinguish different hand-written characters. With this method, $91\%$ recognition rate was acquired.

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권10호
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• pp.990-1002
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• 2005

자연스러운 텍스트를 생성하기 위해서는, 한번 언급된 대상을 지시하기 위한 대용화(pronominalization)과정이 필수적이며, 특히 한국어에 빈번히 발생하는 영형(zero pronoun)을 자연스럽게 생성하는 것이 중요하다. 본 논문에서는, 비용기반 중심화 이론(cost-based centering theory)을 적용하여, 선행 발화의 중심 전이(center transition)가 현 발화의 영형에 미치는 영향을 살펴본다. 이를 위해, 영형으로 실현될 수 있는 명사를 중심화 이론에 기반해 문장간 현저성, 문장내 현저성, 문장간/내 현저성을 가지는지의 여부로 4가지 유형(Npair, Ninter, Nintra, Nnon)으로 정의하고, 유형별로 영형 현상을 고찰하였다. 그 결과, 기존에 중심화 이론에서 배제되었던 명사들이 선행 발화의 중심 전이로 설명될 수 있음을 밝혔다. 또, 선행 발화의 중심 전이를 이용한 영형 생성 모델을 구축하여 다양한 자질을 적용한 영형 생성 모델의 성능과 비교하였다.

• Journal of the Korean Statistical Society
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• 제36권2호
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• pp.257-274
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• 2007

This paper considers the tests for the presence of smooth transition non-linearity in the partially nonstationary vector autoregressive model. The transition parameters cannot be identified under the null hypothesis of linearity, and therefore this paper develops the tests for smooth transition nonlinearity, the associated asymptotic theory and the bootstrap inference. The Monte Carlo simulation evidence shows that the bootstrap inference generates moderate size and power performances.

• Journal of Magnetics
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• 제13권4호
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• pp.140-143
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• 2008

The magnetic and structural properties of transition metal (Mn, Fe, Co) monolayers on Ta(001) surfaces are investigated theoretically by using the first principles full-potential linearized augmented plane wave method. Mn and Fe monolayers become ferromagnetic on Ta(001) surfaces while Co monolayers becomes non-magnetic. The paramagnetism of Co monolayers is explained by the Stoner theory of magnetism. The magnetic coupling of a transition metal overlayer with a substrate is ascribed to the orbital hybridization between the s and d orbitals of the transition metal.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2973-2978
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• 2009

The decomposition reaction mechanism of $CH_3CF_2O$ radical formed from hydroflurocarbon, $CH_3CHF_2$ (HFC-152a) in the atmosphere has been investigated using ab-initio quantum mechanical methods. The geometries of the reactant, products and transition states involved in the decomposition pathways have been optimized and characterized at DFT-B3LYP and MP2 levels of theories using 6-311++G(d,p) basis set. Calculations have been carried out to observe the effect of basis sets on the optimized geometries of species involved. Single point energy calculations have been performed at QCISD(T) and CCSD(T) level of theories. Out of the two prominent decomposition channels considered viz., C-C bond scission and F-elimination, C-C bond scission is found to be the dominant path involving a barrier height of 12.3 kcal/mol whereas the F-elimination path involves that of a 28.0 kcal/mol. Using transition-state theory, rate constant for the most dominant decomposition pathway viz., C-C bond scission is calculated at 298 K and found to be 1.3 ${\times}$ 10$^4s{-1}$. Transition states are searched on the potential energy surfaces involving both decomposition channels and each of the transition states are characterized. The existence of transition states on the corresponding potential energy surface are ascertained by performing Intrinsic Reaction Coordinate (IRC) calculation.

• 한국수학사학회지
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• 제19권2호
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• pp.59-76
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• 2006

본 논문은 탈근대화의 영향으로 등장한 카오스 이론의 시각으로, 수학과 미술의 관련성을 연구하였다 중세 말에서 르네상스로 접어드는 13-14세기, 르네상스의 개화기인 15, 16세기 그리고 16세기말에서 바로크 시대로 접어드는 세 시기에 시대정신이 역동적 체계에서 어떻게 구축되는지를 조망하였다. 시간의 흐름과 더불어 역동적으로 변모해가는 문화와 역사는복잡계의 전형이기 때문이다.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.11-15
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• 2017

We present a study of transition metal compounds using density functional theory (DFT), and density-corrected density functional theory(DC-DFT). By replacing the self-consistent density with that obtained from Hartree-Fock calculation, i.e., HF-DFT, the abnormality driven by self-interaction error is removed in several important cases. We discuss when and how HF-DFT works by examining 3d orbital dimers using approximate functionals and by comparing the results from self-consistent-DFT and HF-DFT with experimental values.