• International Journal of Computer Science & Network Security
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• 제21권1호
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• pp.220-225
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• 2021

Human population growth rate is an important parameter for real-world planning. Common approaches rely upon fixed parameters like human population, mortality rate, fertility rate, which is collected historically to determine the region's population growth rate. Literature does not provide a solution for areas with no historical knowledge. In such areas, machine learning can solve the problem, but a multitude of machine learning algorithm makes it difficult to determine the best approach. Further, the missing feature is a common real-world problem. Thus, it is essential to compare and select the machine learning techniques which provide the best and most robust in the presence of missing features. This study compares 17 machine learning techniques (base learners and ensemble learners) performance in predicting the human population growth rate of the country. Among the 17 machine learning techniques, random forest outperformed all the other techniques both in predictive performance and robustness towards missing features. Thus, the study successfully demonstrates and compares machine learning techniques to predict the human population growth rate in settings where historical data and feature information is not available. Further, the study provides the best machine learning algorithm for performing population growth rate prediction.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.38-74
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• 1996

Recently, the development of new crystal materials for optical applications has become a focus of considerable interest because of the progress of optoelectronic technologies. We have carried out investigations focussing on the development of new optical and electrical materials, by systematic investigations of advanced crystal growth techniques. Here, research and progress in development of new materials and crystal growth techniques is reviewed.

• 한국결정성장학회지
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• 제4권1호
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• pp.1-10
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• 1994

It is well known that crystal growth is an essential area of research for optoelectronic materials. In the present paper the growth techniques and the advanced progress in development of crystal materials important for optoelectronic applications are described. New growth techniques, developed in the authors' laboratory, enabling the introduction of expanded applications of new materials are presented. After a review of recent developments of new techniques for optoelectronic materials, own experimental studies will be discussed.

• East Asian Economic Review
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• 제19권1호
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• pp.39-70
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• 2015

This paper examines the effects of foreign direct investment (FDI) on South Asian economies' output growth, utilizing recent panel cointegration testing and estimation techniques. Annual panel data on eight SAARC (South Asian Association for Regional Cooperation) member countries' macroeconomic variables over the period 1960- 2013 are employed in empirical analysis. Using various heterogeneous panel cointegration and panel causality tests, a bi-directional relationship between FDI and growth is found. We find evidence for both FDI-led growth and growth-induced FDI hypotheses for the South Asian economies over the sample period. Individual member countries exhibit heterogeneity in terms of the direction or existence of causality subject to their idiosyncratic economic conditions. Among various regressors, FDI, financial development, human capital, and government consumption show the most significant positive effects on output growth. As determinants of FDI, GDP, financial development, human capital, and government consumption are found significant in the region. The bi-directional causality between FDI and growth is found robust to the inclusion of other control variables and using different estimation techniques.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
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• pp.653-657
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• 2008

디지털 콘텐츠 관련 산업은 급속도로 성장하고 있으며, 고부가가치를 창출하는 산업으로 주목받고 있다. 디지털 영상 콘텐츠 산업에서 컴퓨터 그래픽스 기술은 핵심기술이라 할 수 있는데, 이 기술은 실제 카메라를 사용하여 촬영하기 어려운 장면이나 연출을 가능하게 함으로써 콘텐츠 제작의 폭을 훨씬 넓혀 주었다. 최근 컴퓨터 그래픽스 기술은 블록버스터 영화, 게임, 교육용 콘텐츠, 시뮬레이션 등 다양한 분야에 적용되고 있으며, 콘텐츠를 구성하는 각 객체의 움직임이나 객체 변화의 자동화에 대한 많은 연구가 이루어지고 있다. 본 논문에서는 3D 모핑기술을 활용하여 어류의 성장 첫 단계인 알에서부터 성어가 되기까지의 과정을 보여주며, 성장에 영향을 미치는 여러 가지 환경요인들에 따라 성장 후 정상적인 성어와의 차이를 알아볼 수 있는 어류 성장과정 시스템을 설계하고자 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.462-462
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• 2013

Gallium Oxide (Ga2O3) has been widely investigated for the optoelectronic applications due to its wide bandgap and the optical transparency. Recently, with the development of fabrication techniques in nanometer scale semiconductor materials, there have been an increasing number of extensive reports on the synthesis and characterization of Ga2O3 nano-structures such as nano-wires, nanobelts, and nano-dots. In contrast to typical vaporliquid-solid growth mode with metal catalysts to synthesis 1-dimensional nano-wires, there are several difficulties in fabricating the nanostructures by using sputtering techniques. This is attributed to the fact that relatively low growth temperatures and higher growth rate compared with chemical vapor deposition method. In this study, Ga2O3 chestnut burr were synthesized by using radio-frequency magnetron sputtering method. In contrast to typical sputtering method with sintered ceramic target, a Ga2O3 powder (99.99% purity) was used as a sputtering target. Several samples were prepared with varying the growth parameters, especially he growth time and the growth temperature to investigate the growth mechanism. Samples were characterized by using XRD, SEM, and PL measurements. In this presentation, the details of fabrication process and physical properties of Ga2O3 nano chestnut burr will be reported.

• 한국군사과학기술학회지
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• 제1권1호
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• pp.227-237
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• 1998

HgCdTe Is the most versatile material for the developing infrared devices. Not like III-V compound semiconductors or silicon-based photo-detecting materials, HgCdTe has unique characteristics such as adjustable bandgap, very high electron mobility, and large difference between electron and hole mobilities. Many research groups have been interested in this material since early 70's, but mainly due to its thermodynamic difficulties for preparing materials, no single growth technique is appreciated as a standard growth technique in this research field. Solid state recrystallization(SSR), travelling heater method(THM), and Bridgman growth are major techniques used to grow bulk HgCdTe material. Materials with high quality and purity can be grown using these bulk growth techniques, however, due to the large separation between solidus and liquidus line on the phase diagram, it is very difficult to grow large materials with minimun defects. Various epitaxial growth techniques were adopted to get large area HgCdTe and among them liquid phase epitaxy(LPE), metal organic chemical vapor deposition(MOCVD), and molecular beam epitaxy(MBE) are most frequently used techniques. There are also various types of photo-detectors utilizing HgCdTe materials, and photovoltaic and photoconductive devices are most interested types of detectors up to these days. For the larger may detectors, photovoltaic devices have some advantages over power-requiring photoconductive devices. In this paper we reported the main results on the HgCdTe growing and characterization including LPE and MOCVD, device fabrication and its characteristics such as single element and linear array($8{\times}1$ PC, $128{\times}1$ PV and 4120{\times}1$ PC). Also we included the results of the dewar manufacturing, assembling, and optical and environmental test of the detectors.

• International Journal of Aerospace System Engineering
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• 제7권1호
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• pp.7-15
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• 2020

In this paper the crack growth, modeling, and simulation of the stiffened and un-stiffened cracked panels presented using commercially available finite element software packages. Computation of stresses and convergence of stress intensity factor for single edge notch (SEN) specimens carried out using the finite element method (FEM) and extended finite element method (XFEM) and compared with an analytical solution. XFEM techniques like cohesive segment method and LEFM using virtual crack closure technique (VCCT), used for crack growth analysis and presented results for un-stiffened and stiffened panels considering various crack domain. The non-linear analysis considering both geometric and material non-linearity on stiffened panels with various stringers like a blade, L, inverted T and Z sections the results were presented. Arrived at the optimum stringer section type for the considered panel under axial loading from the numerical analysis.

• 한국결정성장학회지
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• 제15권5호
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• pp.198-201
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• 2005

Carbon nanofibers were formed on silicon substrate which was applied by negative direct current (DC) bias voltage using microwave plasma-enhanced chemical vapor deposition method. Formation of carbon nanofibers were varied according to the variation of the applied bias voltage. At -250 V, we found that the growth direction of carbon nanofibers followed the applied direction of the bias voltage. Based on these results, we suggest one of the possible techniques to control the growth direction of the carbon nanofibers.

• 한국지반환경공학회 논문집
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• 제20권1호
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• pp.27-33
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• 2019

산성배수가 발생하는 비탈면에서 생태적 녹화를 위한 산성배수 중화기법을 알아보기 위한 연구를 진행하였다. 산성배수중화기법을 위한 4가지 유형의(무처리, 석회고토 처리, 인산염 처리, 석회고토 + 인산염 처리) 시험구를 조성하였다. 실험결과 산도(pH), 피복율(%), 고사율(%), 식물뿌리상태 등에서 중화기법에 따른 유의차가 발생하는 것을 알 수 있었다. 중화기법에 따른 연구결과 (첫 번째 : 석회고토 + 인산염 처리, 두 번째 : 인산염 처리, 세 번째 : 석회고토 처리, 네 번째 : 무처리) 순서로 산도 중화 및 식물생장에 효과적이었다. 산성배수 비탈면에서 석회고토 처리와 인산염 처리는 토양산도 중화와 식물생장에 효과적이었으나, 석회고토 처리에 비해 인산염 처리가 더 효과적이었으며, 인산염 처리가 황화광물의 코팅 효과 때문에 토양산도 중화와 식물 생장에 더 효과적이라는 것을 알 수 있었다.