• 제목/요약/키워드: Ridge Analysis

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인접 융선과의 연관성 분석을 이용한 특징점 추출 알고리즘 (Association analysis using the adjacent feature point Ridge Extraction algorithm)

  • 김강;성연철
    • 한국컴퓨터정보학회:학술대회논문집
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    • 한국컴퓨터정보학회 2012년도 제45차 동계학술발표논문집 20권1호
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    • pp.37-40
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    • 2012
  • 본 논문에서는 지문 인식 시스템의 인식을 위한 등록점으로 융선의 단점과 분기점에 관하여 연구하였다. 원 지문 영상은 전처리 과정을 거치게 되면서 잘못된 특징점을 포함하게 되며 이는 지문 인식 시스템의 효율성을 감소시키는 원인이 될 수 있다. 이 논문에서는 세선화된 지문 영상으로부터 후보 특징점을 추출한 후 연결성 탐색 정보를 이용하여 의사 특징점을 제거할 수 있는 알고리즘을 제안한다.

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Optimal Design of Dielectric-loaded Surface Plasmon Polariton Waveguide with Genetic Algorithm

  • Jung, Jae-Hoon
    • Journal of the Optical Society of Korea
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    • 제14권3호
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    • pp.277-281
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    • 2010
  • We propose a design and optimization method for a dielectric-loaded surface plasmon polariton waveguide using a genetic algorithm. This structure consists of a polymer ridge on top of two layers of substrate and gold film. The thickness, width and refractive index of the ridge are designed to optimize the figures of merit including mode confinement and propagation length. The modal analysis combined with the effective index method shows that the designed waveguide exhibits a fundamental propagation mode with high mode confinement while ensuring that the propagation loss remains relatively low.

Effect of micro-environment in ridge and southern slope on soil respiration in Quercus mongolica forest

  • Lee, Jae-Seok
    • Journal of Ecology and Environment
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    • 제42권4호
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    • pp.210-218
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    • 2018
  • Background: Soil respiration (Rs) is a major factor of the absorption and accumulation of carbon through photosynthesis in the ecosystem carbon cycle. This directly affects the amount of net ecosystem productivity, which affects the stability and sustainability of the ecosystem. Understanding the characteristics of Rs is indispensable to scientifically understand the carbon cycle of ecosystems. It is very important to study Rs characteristics through analysis of environmental factors closely related to Rs. Rs is affected by various environmental factors, such as temperature, precipitation, soil moisture, litter supply, organic matter content, dominant plant species, and soil disturbance. This study was conducted to analyze the effects of micro-topographical differences on Rs in forest vegetation by measuring the Rs on the ridge and southern slope sites of the broadly established Quercus mongolica forest in the central Korean area. Method: Rs, Ts, and soil moisture data were collected at the southern slope and ridge of the Q. mongolica forest in the Mt. Jeombong area in order to investigate the effects of topographical differences on Rs. Rs was collected by the closed chamber method, and data collection was performed from May 2011 to October 2013, except Winter seasons from November to April or May. For collecting the raw data of Rs in the field, acrylic collars were placed at the ridge and southern slope of the forest. The accumulated surface litter and the soil organic matter content (SOMC) were measured to a 5 cm depth. Based on these data, the Rs characteristics of the slope and ridge were analyzed. Results: Rs showed a distinct seasonal variation pattern in both the ridge and southern slope sites. In addition, Rs showed a distinct seasonal variation with high and low Ts changes. The average Rs measurements for the two sites, except for the Winter periods that were not measured, were $550.1\;mg\;CO_2m^{-2}h^{-1}$ at the ridge site and $289.4\;mg\;CO_2m^{-2}h^{-1}$ at the southern slope, a difference of 52.6%. There was no significant difference in the Rs difference between slopes except for the first half of 2013, and both sites showed a tendency to increase exponentially as Ts increased. In addition, although the correlation is low, the difference in Rs between sites tended to increase as Ts increased. SMC showed a large fluctuation at the southern slope site relative to the ridge site, as while it was very low in 2013, it was high in 2011 and 2012. The accumulated litter of the soil surface and the SOMC at the depth range of 0~5 cm were $874g\;m^{-2}$ and 23.3% at the ridge site, and $396g\;m^{-2}$ and 19.9% at the southern slope site. Conclusions: In this study, Rs was measured for the ridge and southern slope sites, which have two different results where the surface litter layer is disturbed by strong winds. The southern slope site shows that the litter layer formed in autumn due to strong winds almost disappeared, and while in the ridge site, it became thick due to the transfer of litter from the southern slope site. The mean Rs was about two times higher in the ridge site compared to that in the southern slope site. The Rs difference seems to be due to the difference in the amount of litter accumulated on the soil surface. As a result, the litter layer supplied to the soil surface is disturbed due to the micro-topographical difference, as the slope and the change of the community structure due to the plant season cause heterogeneity of the litter layer development, which in turn affects SMC and Rs. Therefore, it is necessary to introduce and understand these micro-topographical features and mechanisms when quantifying and analyzing the Rs of an ecosystem.

SNS 기반 여론 감성 분석 (Sentiment Analysis for Public Opinion in the Social Network Service)

  • 하상현;노태협
    • 문화기술의 융합
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    • 제6권1호
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    • pp.111-120
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    • 2020
  • 본 연구는 소셜네트워크서비스(SNS)상의 빅데이터를 이용한 텍스트 분석기법의 응용으로서 설문 조사 기반의 여론 조사 방법론과 달리 비정형적 언어 기반의 감성 여론 조사 방법론을 제안한다. 기존의 설문 기반 여론 분석모형에 대한 대안적 방법으로 주관성에 기초한 감성 분류 모형을 이용하였다. 이를 위하여, 제20대 국회의원 선거운동 기간 중 선거 관련 실시간 트위터 자료를 수집하여 속성 기반 감성 분석을 이용한 여론의 극성과 강도에 대한 실증 분석을 수행하였다. 개별 SNS에서 사용된 단어의 극성을 분류하기 위해 Lasso 및 Ridge 회귀 모형을 이용하여 극성에 영향력이 큰 변수를 추출하였다. 추출된 변수가 극성에 미치는 긍정 및 부정에 대한 영향을 구분하고, 영향력의 강도를 분석하였다. 대중들이 소셜네트워크상에서 표현한 내용을 바탕으로 한 여론에 대한 긍정 및 부정의 감성 분석을 통해 여론의 향방을 예측하고 극성분석 모형의 정확도를 측정하여, 여론 조사 분야에서 감성 분석 방법론의 적용가능성을 확인하였다.

능선 궤적법을 이용한 볼엔드밀 가공면 해석 (Analysis of Machined Surfaces by Ball-end Milling using the Ridge Method)

  • 정태성;남성호;박진호;양민양
    • 한국정밀공학회지
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    • 제21권1호
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    • pp.51-60
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    • 2004
  • Ball-end milling is one of the most common manufacturing processes for the parts with sculptured surface. However, the conventional roughness model is not suitable for the evaluation of surface texture and roughness under highly efficient machining conditions. Therefore, a different approach is needed for the accurate evaluation of machined surface. In this study, a new method, named ‘Ridge method’, is proposed for the effective prediction of the geometrical roughness and the surface topology in ball-end milling. Theoretical analysis of a machined surface texture was performed considering the actual trochoidal trajectories of cutting edge. The characteristic lines of cut remainder are defined as three-types of ‘Ridges’ and their mathematical equations are derived from the surface generation mechanism of ball-end milling process. The predicted results are compared with the results of conventional method. The agreement between the results predicted by the proposed method and the values calculated by the simulation method shows that the analytic equations presented in this paper are useful for evaluating a geometrical surface roughness of ball -end milling process.

Strategic coating of NdFeB magnets with Dy to improve the coercivity of permanent magnets

  • Ucar, Huseyin;Parker, David S.;Nlebedim, I.C.;McCallum, R.W.;McCall, S.K.;Parans Paranthaman, M.
    • Advances in materials Research
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    • 제4권4호
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    • pp.227-233
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    • 2015
  • We present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in $Nd_2Fe_{14}B$ (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are largest, rather than uniformly throughout the bulk sample. A200 nm thick Dy film was sputtered onto a commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from $600-700^{\circ}C$. Magnets displayed enhanced coercivities after post-annealing and as much as a 5 % increase in the energy product, while requiring a total Dy content of 0.06 wt. % - a small fraction of that used in the commercial grade Dy-NdFeB magnets. By assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing which would potentially broaden the application space of these magnets in the traction motors of hybrid and pure electric vehicles, and wind generators.

식생여과대 유사 저감 효율 산정을 위한 정규화 방안 (A Study on Regularization Methods to Evaluate the Sediment Trapping Efficiency of Vegetative Filter Strips)

  • 배주현;한정호;양재의;김종건;임경재;장원석
    • 한국농공학회논문집
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    • 제61권6호
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    • pp.9-19
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    • 2019
  • Vegetative Filter Strip (VFS) is the best management practice which has been widely used to mitigate water pollutants from agricultural fields by alleviating runoff and sediment. This study was conducted to improve an equation for estimating sediment trapping efficiency of VFS using several different regularization methods (i.e., ordinary least squares analysis, LASSO, ridge regression analysis and elastic net). The four different regularization methods were employed to develop the sediment trapping efficiency equation of VFS. Each regularization method indicated high accuracy in estimating the sediment trapping efficiency of VFS. Among the four regularization methods, the ridge method showed the most accurate results according to $R^2$, RMSE and MAPE which were 0.94, 7.31% and 14.63%, respectively. The equation developed in this study can be applied in watershed-scale hydrological models in order to estimate the sediment trapping efficiency of VFS in agricultural fields for an effective watershed management in Korea.

발치와 치조제 보존술 후 식립한 임플란트 주위 골 변화: 후향적 방사선학적 분석 (Periimplant bone change after alveolar ridge preservation: radiographic retrospective study)

  • 심다은;방은경
    • 대한치과보철학회지
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    • 제59권3호
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    • pp.281-290
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    • 2021
  • 목적: 구치부 임플란트 식립을 위하여 발치와 치조제 보존술을 시행한 환자를 대상으로 임플란트 식립 직 후, 최종 보철물 장착 후 및 유지관리 기간에 따른 치조제 높이 변화량을 방사선학적으로 측정하여 임플란트 주위 골 변화를 평가하고자 하였다. 대상 및 방법: 치조제 보존술을 시행한 후 식립한 총 36개의 임플란트를 대상으로 각 시기에 촬영한 파노라마 방사선 사진을 이용하여 근·원심측의 치조제 높이를 각각 수직적 수치로 측정하였다. 환자의 연령, 성별, 전신질환, 임플란트 식립 위치, 골 이식재 유형, 차폐막 적용 방법, 술자의 숙련도, 측정 시기간의 치조제 높이 변화량은 평균, 표준편차를 구하였고, 치조제 높이 변화량과 각각의 요소들 간의 연관성은 독립표본 t검정, 기간별 측정한 치조제 높이 간의 연관성은 대응표본 t검정을 시행하였다(P < .05). 결과: 각 시기별 치조제 높이 변화량은 각각의 시기 사이에 모두 통계적으로 유의한 차이를 보였고(P < .05), 각 시기 간의 치조제 높이 변화량과 평가된 요소들은 통계적으로 유의한 연관성을 보이지 않았다. 결론: 발치와 치조제 보존술 후 식립된 임플란트 주위 골조직은 환자 및 수술적 요소에 영향을 받지 않고 유지기간동안 안정적으로 유지되었으며, 발치와 치조제 보존술은 임상적으로 사용가능한 술식이라고 사료된다.

슬레드 시험용 폭발볼트 개발 (Development of an Explosive Bolt for Sled Test Application)

  • 이주호;안우진;김용석
    • 한국항공우주학회지
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    • 제48권4호
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    • pp.269-275
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    • 2020
  • 폭발볼트는 내부 화약의 폭발력에 의해 결합되어진 두 개의 구조물을 분리하는 대표적인 파이로 분리장치이다. 본 연구에서는 슬레드 시험에 사용이 가능하도록 EBW 기폭관을 적용한 1/2" 리치컷형 폭발볼트를 개발하였다. 설계 방법론으로부터 초기 형상 설계를 수행하였으며, 성능 시험을 통해 분리 성능은 우수하나 파편이 발생함을 확인하였다. 이에 전산수치해석을 통해 화약량을 최소화하여 파편 발생을 줄이고자 하였다. 전산수치해석으로부터 리치컷형 폭발볼트의 분리 메커니즘과 특성을 확인하였으며, 파편을 발생시키지 않는 최소 화약량을 제시하였다. 검증 시험을 통해 제시된 화약량을 적용하면 분리 성능을 유지하면서 파편이 감소되는 것을 확인하였다.

하악 견치 잔존시 의치 설계에 따른 치아 지지조직 및 잔존치조제의 광탄성 응력분석 (A PHOTOELASTIC STRESS ANALYSIS ON TOOTH SUPPORTING STRUCTURE AND RESIDUAL RIDGE ACCORDING TO DENTURE DESIGN FOR REMAINING MANDIBULAR CANINES)

  • 김일평;고준원;진태호
    • 대한치과보철학회지
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    • 제35권3호
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    • pp.486-503
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    • 1997
  • The purpose of this study was to evaluate the stress patterns developed in abutment and residual ridge according to removable denture design in case of remaining mandibular canines. The removable denture designs in this study were as foolows : 1. Removable partial denture with non-splinted abutment 2. Removable partial denture with splinted abutment 3. Overdenture with telescopic crown 4. Overdenture with O-Ring attachment 5. Overdenture with combination bar attachment Photoelastic stress analysis was used to record the isochromatic fringe patterns and to calculate principal stress components at measuring points. The results were as follows : 1. In case of removable partial denture with non-splinted abutment, stress of root area at the loaded side was the largest. No significant differences in stress of root area were observed between loaded side and unloaded side. 2. No significant differences in stress of residual ridge at the loaded side were observed between removable partial denture with splinted abutment and removable partial denture with non-splinted abutment. 3. In case of combination bar attachment retained overdenture, stress of root area was the largest and in case of telescopic crown retained overdenture, stress of root area was the lowest. 4. In case of attachment retained overdenture, stress of residual ridge was lower but stress of root area was larger than in case of removable partial denture.

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