• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.978-982
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• 2007

A new neuro-control scheme for active control of structures is proposed. It utilizes lattice pattern of state vector as training data of probabilistic neural network (PNN). Therefore, it is the so-called lattice probabilistic neural network (LPNN). PNN makes control forces by using all the training patterns. Therefore, it takes much time to obtain a control force in application. This inevitably may delay the control action. However, control force of LPNN is calculated by using only the adjacent information of LPNN input. So, the response of LPNN is greatly faster than PNN. The proposed control algorithm is applied for one story building under California and El Centro earthquakes. Also, control results of the LPNN are compared with those of the conventional PNN. The structural responses have been suppressed effectively by the proposed algorithm.

• 소성∙가공
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• 제32권5호
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• pp.255-267
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• 2023

Recently, 3D printing using a material extrusion method is used in various fields. Since plastic material has lower strength than steel, research to increase the strength is continuously being conducted. This study investigates the lattice structure for additive manufacturing of six 3D infill patterns (octet, quarter cubic, cubic, cubic subdivision, triangles and cross 3D) which consist of tetragons, hexagonal trusses, equilateral triangles and cross shapes. Consequently, in the tensile strength considering the weight and printing time, octet, quarter cubic, cubic and triangles patterns tended to increase linearly as the infill density increased, except for the infill density of 20%. However, the tensile strength/weight performed better than the infill density of 100% when the cubic subdivision pattern had the infill density of 20% and the cross 3D pattern had the infill density of 40%. Considering the weight and printing time, the infill patterns of high tensile strength were octet, quarter cubic, cubic, cubic subdivision, triangles and cross 3D order.

• Bulletin of the Korean Chemical Society
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• 제29권10호
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• pp.1969-1972
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• 2008

In this study, horse spleen apoferritins were induced to form biominerals using up to 3000 Fe atoms per protein molecule. The morphology and crystallinity of the nanometer-sized biominerals formed in the ferritins were then analyzed using field emission-energy filtering-transmission electron microscopy (FE-TEM). The ferritins were found to have reconstitution yields of 60-70% in the experiments. The mean core size of the ferritins varied somewhat with protein concentrations, indicating that crystal growth in ferritins could be controlled via protein concentrations. The core mineral size increased with the amount of Fe used. Lattice fringes of the core, associated with good crystallinity, were found in all samples. The lattice fringe images of a single domain ferrihydrite mineral appeared frequently in the (011) planes (d-spacing of 0.246 nm) under [100] zone axis in all samples of this study. In addition, the lattice image occasionally revealed fringes corresponding to the (100) planes (d = 0.254 nm) from the [001] zone axis, indicating the characteristic pattern of hexagonal crystal lattice. Diffraction patterns in the minerals identified as ferrihydrite were fitted well into the space group of $P3_{1c}$.

• Journal of the korean society of oceanography
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• 제36권1호
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• pp.9-18
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• 2001

Chemical speciation of five heavy metals (Cr, Cu, Ni, Pb, Zn) has been analyzed from 37 surface and 2 core sediments of Kyeonggi Bay, using the modified sequential extraction method based on Tessier et at. (1979). The results show that heavy metals in the Kyeonggi Bay surface sediments are associated dominantly with the crystal lattice fraction. But in the polluted sediments of the Incheon North Harbor, the importance of the labile fractions increased while that of the lattice fraction decreased. In particular, the adsorbed and the easily reducible fractions showed a noticeable increase. In the core samples emerged a speciation pattern which differed significantly from that of the surface sediments. A sharp increase in the percentage of the reducible and organic/sulfide fractions and a decrease in the lattice fraction were observed. Throughout the vertical column, however, the metal contents in the lattice fraction showed stability while those of the labile fractions showed an upward increase. The strong association of heavy metals with the organic/sulfide fraction could be attributed in part to the sulfate reduction prevailing in the polluted harbor sediments.

• 한국전산구조공학회논문집
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• 제28권1호
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• pp.53-61
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• 2015

본 논문에서는 대공간구조에 폭넓게 사용되는 단층 래티스돔의 비선형거동에 관한 비교 연구를 수행하였다. 단층 래티스돔은 특성상 두께가 얇은 쉘구조의 거동과 유사하므로 전통적인 쉘좌굴 이론을 적용하여 내력을 산출할 수 있으며 또한 이 결과를 유한요소해석 프로그램을 이용한 수치해석의 결과와 비교, 분석하였다. 쉘좌굴 이론을 이용하여서는 래티스 돔의 전체좌굴하중과 부재좌굴하중을 산정하였으며, 유한요소해석법을 이용하여서는 고유치 해석에 의한 좌굴하중과 기하학적 비선형 해석에 의한 극한하중을 각각 산정하였다. 래티스돔의 절점은 강절점 및 핀절점으로 각각 모델링하였다. 쉘좌굴이론에 의한 좌굴내력은 전체좌굴하중과 부재좌굴하중의 작은 값으로 결정되며 이 값은 유한요소해석을 이용한 고유치 해석보다는 비선형 해석에 의한 극한하중에 보다 근사한 값을 제공하였으며 또한 좌굴하중의 형식을 예측하는데에 유용하게 활용되었다.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.391-396
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• 2011

The tracking pattern formed on the dielectric surface due to a surface electrical discharge exhibits fractal structure. In order to quantitatively investigate the fractal characteristics of the surface tracking pattern, the dielectric breakdown model has been employed to numerically generate the surface tracking pattern. In dielectric breakdown model, the pattern growth is determined stochastically by a probability function depending on the local electric potential difference. For the computation of the electric potential for all points of the lattice, a two-dimensional discrete Laplace equation is solved by mean of the successive over-relaxation method combined to the Gauss-Seidel method. The box counting method has been used to calculate the fractal dimensions of the simulated patterns with various exponent $\eta$ and breakdown voltage $\phi_b$. As a result of the simulation, it is found that the fractal nature of the surface tracking pattern depends strongly on $\eta$ and $\phi_b$.

• 한국전통조경학회지
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• 제36권3호
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• pp.160-171
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• 2018

꽃창살은 사찰경관을 구성하는 조형요소이며 조망시점이 외부에서 형성되는 장식적 경관요소라는 인식 아래, 경북 영주시 성혈사 나한전의 꽃창살에 표현된 연지의 생태미학적 특성과 도입된 소재의 상징성을 분석 해석한 본 연구의 결과는 다음과 같다. 나한전 정칸 창호에는 사각형 2개가 연속된 문틀 등 비목재 부분을 제외하고 총 176개의 순수 문양이 조각되어 있다. 그 중 중문 어칸(御間) 문살의 기본 개념은 전통정원에서 방지(方池)를 상징하는 연지의 설계언어로 판단된다. 창살 어칸에서 가장 비중이 높은 식물인 연꽃은 '청정(淸淨)'과 '불염(不染)' 그리고 불교의 극락세계인 연화장세계로 인식되며 꽃창살에 묘사된 연꽃은 생성소멸의 특징을 담은 다채로운 형태로 펼쳐져 있어 불연일체(佛蓮一體)의 경관상(景觀像)이 잘 드러나고 있다. 또한 네가래와 벗풀은 실제 연못 주변에서 발견되는 수생식물로 생태적 측면에서도 연지의 수생태계와도 부합되는 사실적 표현일 뿐 아니라 물총새, 백로, 왜가리 등 날짐승의 표현은 정적인 수생태계에 동세와 활력을 불어넣고자 한 생태미학적 발상이다. 또한 동자승을 비롯하여 수(壽) 부(富) 귀(貴) 다남(多男) 등의 기복사상을 구현하고자 한 것으로 판단되는 물총새, 기러기(백로), 물고기, 참게, 개구리 그리고 용 등 7개 분류형의 동물들과 식물이 공생하는 연지풍경을 꽃창살에 연출하였다. 성혈사 나한전 어칸의 꽃창살은 연과 연잎의 생성과 소멸, 서식처의 생태적 적지(敵地), 공생과 먹이연쇄 등 수생태계 측면에서도 매우 부합되는 표현으로 가득하며 이는 상징과 생태미학의 총화이자연지 풍경의 총합적 어울림이다.

• Applied Microscopy
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• 제25권3호
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• pp.99-107
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• 1995

The morphological changes of primary solid particles as a function of process time on hypereutectic Al-15.5wt%Si alloy during semi-solid state processing with a shear rate of $200s^{-1}$ are studied. In this alloy, it was observed that primary Si crystals are fragmented at the early stage of stirring and morphologies of primary Si crystals change from faceted to spherical during isothermal shearing for 60 minutes. To understand the role of Al dissolved in the primary Si crystal by shear stress at high temperature, lattice parameters of the primary Si crystals are determined as a variation of high order Laue zone(HOLZ) line positions measured from convergent beam electron diffraction(CBED) pattern. The lattice parameter of the primary Si crystal in the rheocast Al-15.5wt%Si alloy shows tensile strain of about 5 times greater than that of the gravity casting. Increase of the lattice parameter by rheocasting is due to the increased amount of Al dissolved in the primary Si crystal accelerated by shear stress at high temperature. The amounts of solute Al in the primary Si crystal are measured quantitatively by EPMA method to confirm the CBED analysis.

• E2M - 전기 전자와 첨단 소재
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• 제8권6호
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• pp.780-786
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• 1995

For the execution of RIETAN program adopting Rietveld Analysis Method, the sample superconductor is made according to the solid state synthesis method at 920.deg. C for 24hrs, and was examined for the optimization of parameters needed to analyze Rietveld method with the input of the measured pattern data after measuring the pattern resulted from the X-ray diffraction. It was proven that the lattice constant of the superconductor which was consisted of Pmmm orthorhombic crystal structure in the analyzed space group correspond to the presented theoretical lattice constant a=3.8887(8).angs., b=3.8238(4).angs., c=11.7079.angs.. Therefore, it was examined and confin-ned that the R factor, which was compensated after analyzing the structure of superconductor resulted from this experimented data with the computer simulation, was refined to $R_{wp}$=8.83[%], $R_{P}$=6.47[%], $R_{I}$=10.08[%], $R_{F}$=7.19[%], $R_{E}$=3.76[%]. On the basis of these experimental data, the significant parameter such as the scale factor(S) and the zero point shift(Z) and FWHM value(U,V,W) were optimized as follows; S=2.0827E-3, Z=0.2146, U=4.2761E-2, V=1.7983E-2, and W=2.6768E-2.2.2.2.2.2.

• 한국멀티미디어학회논문지
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• 제16권7호
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• pp.802-809
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• 2013

본 논문에서는 프로그래밍 언어에 정의되는 지정자와 키워드가 프로그램 코드 상에서 연속적인 패턴으로 나타나게 될 때, 해당 연속 패턴들의 빈도와 길이를 측정하여 두 코드 사이의 유사성을 측정하는 기법을 제안한다. 또한, 이러한 분석 결과를 정형적 개념 분석 기법을 이용하여 가시화하는 기법을 제안한다. 제안 기법은 기존의 유사도 측정 기법에서는 고려하지 않았던 단어 인접성을 유사도 측정에 반영한다. 함수 단위로 지정자와 키워드 패턴을 이용하여 함수의 호출 순서나 수행 순서에 상관없이 표절을 탐지할 수 있다. 또한, 유사도 측정 결과는 정형적 개념 분석 기법을 이용하여 격자(lattice)로 시각화되어 사용자의 이해도를 높일 수 있다. 실험 결과 제안 기법은 96%의 표절 탐지 성공률을 보여주었다. 제안 기법은 프로그램 코드 뿐만 아니라 일반 문서의 분석에도 적용될 수 있다.