• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.5-11
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• 1995

본 연구에서는 화상에 있어서 패턴의 공간적인 특징을 추출하기위한 목적으로 신경회로망을 적용하는 방법을 제안하였다. 적용한 신경회로망은 3중의 구조를 가지며, 그 학습방법으로는 back-propagation 알고리즘을 사용하였다. 또한 이동이나 회전과 같은 패턴의 변위에 대응하기 위하여, 화상으로부터 co-occurrence matrix를 구하여, 신경회로망의 입력패턴으로 사용하였다. 제안한 방법을 평가하기 위하여 종래의 대표적방법인 화소의 spectral 정보를 이용한 최대유도법(maximum likelihood method)으로는 식별이 곤란한 시가지지역과 모래지역을 선정하여, 본 방법과 Haralick에 의하여 제안된 teture features를 이용하여 분류한 결과, texture features를 이용한 방법으로는 67%~89%의 식별률을 얻었음에 반하여, 본 연구에서 제안한 신경회로망을 사용한 방법으로는 80%~98%의 안정되고 높은 식별률을 얻었다.

• 복식문화연구
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• 제21권2호
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• pp.151-166
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• 2013

This study aims to shed light on the diversity and complexity of design represented through modern fashion and to identify growth opportunities for globalizing and modernizing traditional clothing designs. To this end, formative trends and aesthetic characteristics of $21^{st}$ century fashion were analyzed, with an emphasis on Japanism reflected in the works of Western designers. The research methodology consisted of an analysis as well as a literature review. A total of 217 designs with Japanism characteristics were identified from the 2001 S/S collection to the 2011 S/S collection in Paris, Milano, New York, and London, and these were analyzed in terms of image, color details, pattern, and accessories. The research findings with regard to the characteristics of modern fashion designs that reflect Japanism were as follows. First, sensuality was projected by highlighting the erotic elements of Japanese clothing. Second, the underlying principles, styles, and elements of Japan's traditional clothing were embodied in a cross-cultural and eclectic manner that blurred the boundaries between styles by mix-and- matching the traditional and the contemporary, the East and the West, and different styles. Third, a variety of patterns, colors, accessories, and design techniques associated with Japanese traditional clothing played a critical role in creating flamboyant and decorative images in contemporary fashion. Fourth, the overlapping of the kimono style, the flat design that accentuates body curves, and the layered style has created a beautifully free-form fashion that demonstrates non-structural features.

• International Journal of Oral Biology
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• 제36권3호
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• Investigative Magnetic Resonance Imaging
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• 제14권2호
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• pp.151-155
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• 2010

일차성 간림프종은 전체 림프절외장기를 침범하는 림프종의 1% 미만에서 나타나는 매우 드문 질환이다. 저자들은 수술로 확진된 일차성 간림프종의 자기공명영상과 병리 소견의 특징을 보고한다. 간세포 특이 조영제를 주입하여 얻은 역동적 조영증강 영상에서 점차적으로 조영증강되어 간내담관암과 유사하게 보였다. 그러나 20분 지연 후 얻은 간담관기 영상과 확산강조영상에서 서로 다른 신호강도를 보이는 세 층의 띠모양의 병변이 특징적으로 보였으며 이는 병리적으로 외층의 생존 종양, 중간층의 괴사된 종양, 및 종양에 둘러싸인 중앙부의 괴사된 간 실질과 일치되는 소견을 보였다.

• 한국정보처리학회논문지
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• 제4권7호
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• pp.1759-1769
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• 1997

다층신경회로망의 학습방법인 오류역전도 알고리즘은 연관기억장치, 음성인식, 패턴인식, 로보틱스등과 같은 다양한 응용분야에 널리 사용되고 있다. 그럼에도 불구하고 계속 많은 논문들이 역전도 알고리즘에 대해 발표되고 있는 실정이다. 이러한 연구 동향의 주된 이유는, 뉴런 갯수와 학습 패턴의 갯수가 큰 경우에 역전도 알고리즘의 학습속도가 상당히 느리다는 사실때문이다. 본 연구에서는 가변학습율, 가변모멘텀율, 그리고 시그모이드 함수의 가변기울기를 이용한 새로운 학습속도 가속기법을 개발하였다. 학습이 수행되는 도중에, 이러한 파라메터들은 전체 오류의 변화량에 따라 연속적으로 조정되며, 제안된 기법은 기존의 역전도 알고리즘에 비해 획기적으로 학습시간을 단축시키는 결과를 보였다. 제안된 기법의 효율성을 입증하기 위하여, 처음에는 난수발생기로 생성한 이진 데이터를 이용하여 에포크(epoch) 횟수를 비교할 때 훌륭한 속도 향상을 보였으며, 또한, 기계학습(machine learning)의 벤치마크 학습자료로 많이 사용되는 이진 Monk's data, 4, 5, 6, 7비트 패리티 검사 문제와 실수 Iris data에도 적용하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.817-820
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• 2004

The $Sr_{0.7}Bi_{2.6}Ta_2O_9$(SBT) thin films are deposited on Pt-coated electrode($Pt/TiO_2/SiO_2/Si$) using a RF magnetron sputtering method. The ferroelectric properties of SBT capacitors with annealing time were studied. In the SEM images, Bi-layered perovskite phase was crystallized at 10min and grains largely grew with annealing tune. SBT thin films are transformed from initial amorphous phase to the fully formed layer-structured perovskite. During the annealing process at $750^{\circ}C$, we found that an fluorite-like stage is formed after 3min. In the XRD pattern, the SBT thin films after 3min annealing time had (105) orientation. The ferroelectric properties of SBT capacitor with annealing time represent a favorable properties at 60 min. The maximum remanent polarization and the coercive electric field with 60 min are $12.40C/cm^2$ and 30kV/cm, respectively. The leakage current density with 60min is $6.81{\times}10^{-10}A/cm^2$.

• Smart Structures and Systems
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• 제23권1호
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• pp.81-90
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• 2019

The shear behavior of soil-concrete interface is mainly affected by the surface roughness of the two contact surfaces. The present research emphasizes on investigating the effect of roughness of soil-concrete interface on the interface shear behavior in two-layered laboratory testing samples. In these specially prepared samples, clay silt layer with density of $2027kg/m^3$ was selected to be in contact a concrete layer for simplifying the laboratory testing. The particle size testing and direct shear tests are performed to determine the appropriate particles sizes and their shear strength properties such as cohesion and friction angle. Then, the surface undulations in form of teeth are provided on the surfaces of both concrete and soil layers in different testing carried out on these mixed specimens. The soil-concrete samples are prepared in form of cubes of 10*10*30 cm. in dimension. The undulations (inter-surface roughness) are provided in form of one tooth or two teeth having angles $15^{\circ}$ and $30^{\circ}$, respectively. Several direct shear tests were carried out under four different normal loads of 80, 150, 300 and 500 KPa with a constant displacement rate of 0.02 mm/min. These testing results show that the shear failure mechanism is affected by the tooth number, the roughness angle and the applied normal stress on the sample. The teeth are sheared from the base under low normal load while the oblique cracks may lead to a failure under a higher normal load. As the number of teeth increase the shear strength of the sample also increases. When the tooth roughness angle increases a wider portion of the tooth base will be failed which means the shear strength of the sample is increased.

• 지질공학
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• 제31권3호
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• pp.257-267
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• 2021

Constraints on the structure and composition of the active layer are important for understanding permafrost evolution. Soil convection owing to repeated moisture-induced freeze-thaw cycles within the active layer promotes the formation of self-organized patterned ground. Here we present the results of ground penetrating radar (GPR) surveys across a selected sorted circle near King Sejong Station, Antarctica, to better delineate the active layer and its relation to the observed patterned ground structure. We acquire GPR data in both bistatic mode (common mid-points) for precise velocity constraints and monostatic mode (common-offset) for subsurface imaging. Reflections are derived from the active layer-permafrost boundary, organic layer-weathered soil boundary within the active layer, and frozen rock-fracture-filled ice boundary within the permafrost. The base of the imaged sorted circle possesses a convex-down shape in the central silty zone, which is typical for the pattern associated with convection-like soil motion within the active layer. The boundary between the central fine-silty domain and coarse-grained stone border is effectively identified in a radar amplitude contour at the assumed active layer depth, and is further examined in the frequency spectra of the near- and far-offset traces. The far-offset traces and the traces from the lower frequency components dominant on the far-offset traces would be associated with rapid absorption of higher frequency radiowave due to the voids in gravel-rich zone. The presented correlation strategies for analyzing very shallow, thin-layered GPR reflection data can potentially be applied to the various types of patterned ground, particularly for acquiring time-lapse imaging, when electric resistivity tomography is incorporated into the analysis.

• Structural Engineering and Mechanics
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• 제82권1호
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• pp.121-131
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• 2022

The main goal of this study is to prepare a program for analyzing High Strength Steel Fibrous Reinforced Concrete (HSSFRC) slabs and predict the response and strength of the slab instead of preparing a prototype and testing it in the laboratory. For this purpose, new equations are proposed to represent the material properties of High Strength Steel Fibrous Reinforced Concrete. The proposed equations obtained from performing regression analysis on many experimental results using statistical programs. The finite element method is adopted for non-linear analysis of the slabs. The eight-node "Serendipity element" (3 DoF) is chosen to represent the concrete. The layered approach is adopted for concrete elements and the steel reinforcement is represented by a smeared layer. The compression properties of the concrete are modeled by a work hardening plasticity approach and the yield condition is determined depending on the first two stress invariants. A tensile strength criterion is adopted in order to estimate the cracks propagation. many experimental results for testing slabs are compared with the numerical results of the present study and a good agreement is achieved regarding load-deflection curves and crack pattern. The response of the load deflection curve is slightly stiff at the beginning because the creep effect is not considered in this study and for assuming perfect bond between the steel reinforcement and the concrete, however, a great agreement is achieved between the ultimate load from the present study and experimental results. For the models of the tension stiffening and cracked shear modulus, the value of Bg and Bt (Where Bg and Bt are the curvature factor for the cracked shear modulus and tension stiffening models respectively) equal to 0.005 give good results compared with experimental result.

• 한국지반공학회논문집
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• 제23권5호
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• pp.89-100
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• 2007

본 연구에서는 건조 고결층이 형성된 준설 매립 지반의 지반 개량 및 보강을 위한 시공 초기 단계에서 지반의 안정성과 장비의 주행성 평가 시 고려되는 지지력 산정과 관련하여 다양한 실내 및 현장 시험을 수행하였다. 지반조사를 통해 기본물성 특성을 파악하였고 현장 베인 시험 및 일축압축 직접전단시험을 통하여 지반의 깊이별 강도분포와 고결층의 강도 특성 및 응력-변형률 거동을 살펴보았다. 또한 지반의 지지력 평가와 하중-침하 곡선 및 파괴형태를 파악하기 위하여 평판재하시험을 수행하였다. 기존의 2층 지반 지지력 산정 기법을 이용하여 지지력을 산정하였으며 이를 평판재하시험 결과와 비교하여 지지력 산정 기법의 적용 방법에 대하여 논의해 보았다.