철원지역 두루미 취식지의 핵심지역 설정을 위한 MCP, 커널밀도측정법(KDE)과 국지근린지점외곽연결(LoCoH) 분석

유승화 ( Seung Hwa Yoo ),이기섭 ( Ki Sup Lee ),박종화 ( Chong Hwa Park ) 한국환경생태학회 2013 한국환경생태학회지 Vol.27 No.1

본 연구는 두루미(Grus japonensis)의 이용분포 내에서 행동권 분석의 기법인 MCP(최소볼록다각형법), KDE(커널밀도측정법), LoCoH(국지근린지점외곽연결)를 이용하여 이용면적과 핵심서식지를 선정하였다. 또한, 각 기법의 차이와 의미를 고찰하도록 하였다. 두루미의 분포자료는 철원지역 2012년 2월 17일 조사자료를 사용하였다. MCP에 의한 두루미류 서식영역은 140㎢이었다. KDE 분석에서 띠폭에 해당하는 ?값을 1000m, CVh, LSCVh로 달리하여 KDE 등치선을 생성하였을 때, 핵심지역에 해당하는(Kernel 50% 이상) 면적은 33.3㎢(KDE1000m), 25.7㎢(KDECVh), 19.7㎢(KDELSCVh) 이었다. 결과적으로 띠폭에 대한 기본값(1000m)-CVh(554.6m)-LSCVh(329.9m) 순으로 변수를 작게 입력할 경우 핵심면적 개수는 늘어나고, 면적은 감소하였으며, 형태의 복잡성은 증가하였다. 두루미류의 KDE 분석에 의한 핵심지역의 선정에서 적합한 띠폭변수는 CVh 값인 것으로 판단되었다. LoCoH분석에서는 서식범위와 핵심지역 (50% 등치선 이상의 지역)의 면적이 k값의 증가에 따라 증가하는 모습을 보였으며, 점차 큰 핵심지역으로 합쳐지는 모습을 나타내었다. 핵심지역을 도출하기에 적합한 k 값은 24로 나타났으며, 전체 개체군의 핵심지역은 18.2㎢로 전체 서식면적의 16.5%를 차지하였다. 최종적으로, LoCoH 분석은 두 개의 큰 핵심서식지를 제시하였으며, 이것은 KDE에 의한 핵심지역에 비하여 작은 수의 핵심지역을 제시한 것이었다. 국내의 게재논문 및 발표자료를 포함한 연구에서 KDE는 대부분 기본설정으로 분석되었으며, 띠폭에 의한 변수를 고려한 것은 매우 드물었다. 따라서 띠폭변수를 명확히 제시하는 것이 요구되었다. We tried to find out the core feeding site of the Red-crowned Crane(Grus japonensis) in Cheorwon, Korea by using analysis techniques which are MCP(minimum convex polygon), KDE(kernel density estimation), LoCoH(local nearest-neighbor convex-hull). And, We discussed the difference and meaning of result among analysis methods. We choose the data of utilization distribution from distribution map of Red-crowned Crane in Cheorwon, Korea at 17th February 2012. Extent of the distribution area was 140㎢by MCP analysis. Extents of core feeding area of the Red-crowned Crane were 33.3㎢(KDE1000m), 25.7㎢(KDECVh), 19.7㎢(KDELSCVh), according to the 1000m, CVh, LSCVh in value of bandwidth. Extent, number and shape complexity of the core area has decreased, and size of each core area have decreased as small as the bandwidth size(default:1000m, CVh: 554.6m, LSCVh: 329.9). We would suggest the CVh value in KDE analysis as a proper bandwidth value for the Red-crowned crane`s core area zoning. Extent of the distribution range and core area have increased and merged into the large core area as a increasing of k value in LoCoH analysis. Proper value for the selecting core area of Red-crowned Crane`s distribution was k=24, and extent of the core area was 18.2㎢, 16.5% area of total distribution area. Finally, the result of LoCoH analysis, we selected two core area, and number of selected core area was smaller than selected area of KDE analysis. Exact value of bandwidth have not been used in studies using KDE analysis in most articles and presentations of the Korea. As a result, it is needed to clarify the exact using bandwidth value in KDE studies.

보행자 기반 시뮬레이션 지표설정 및 공간구조론과의 상관성 분석

김석태,홍사철 대한건축학회지회연합회 2018 대한건축학회연합논문집 Vol.20 No.3

건축공간의 실체는 물리적이지만 성능은 물리적 기능에 더하여 그 공간의 용도와 내부에서 생활하는 사용자들의 복잡한 상호관계에 의해 이루어진다. 70년대 들어 공간의 특성을 분석하기 위해 다양한 공간구조분석이론이 제시되고 검증되어 왔으나 목적성(동선, 서비스)과 사용자의 특성을 반영할 수 없는 등 많은 한계에 부딪혀왔다. 본 연구에서는 공간을 복잡계의 관점에서 바라보고자 하였으며, 복잡계 분석 이론 중 하나인 Agent based modeling을 이용하여 가능성을 파악하고자 하였다. 이에 space syntax 데이터에 대입할 수 있는 밀도, 통행량, 에이전트의 존속시간 등 3가지 지표를 제시하고, 여기에 8가지 프로토타입 예시공간에 pedestrian based discrete event simulation을 수행하여 raw data를 추출하였다. 또한 오차 내 데이터 수렴시간 분석을 통해 적정시뮬레이션 시간을 도출하였고, 샘플을 이용한 10차례의 반복시뮬레이션과 에이전트 종속시간분석을 통해 work flow chart를 검증하였다. ABM시뮬레이션을 통해 얻은 밀도데이터를 convex map의 분석결과와, 통행량을 axial map분석결과와 피어슨 상관계수를 통한 관계성을 분석하여 다음과 같은 결과를 얻을 수 있었다.1) 10차례의 반복시뮬레이션을 통해 emergence data의 일관성을 확인하였고, 빠른 시간 안에 오차 이내로 데이터가 수렴되는 경향을 확인하였다. 2) 영역밀도(convex map)가 통행량(axial map)에 비하여 높은 상관관계를 보였다. 3) 밀도는 대칭성에 영향을 크게 받으며, 대칭구조가 비대칭구조보다 상관관계가 크다. 통행량은 위상적 특징과 관련이 깊으며, tree 형태가 ring형태보다 상관관계가 크다. 특히 순환형 구조는 ABM의 통행량과 공간구조이론간 상관관계가 없다. 4) VGA는 공간구조이론과 유사한 성향을 보이지만 격차는 작았다. The reality of the architectural space is physical, but the performance of the space is based on not only the physical function of the space but also the usage of the space and the complex interrelationships of users who live in the space. Since 1970, various theories for spatial structure analysis have been proposed and verified in order to analyze the characteristics of space, but they have faced many limitations such as their inability to reflect the purposes of space (moving path, services) and the characteristics of users. In this paper, we tried to look at the space in perspective of the complex system and tried to grasp the possibility by using the Agent-based modeling which is one of the complex system analysis theory. Hence, we propose three metrics, that can be assigned to the space syntax data, such as density, traffic volume and lifetime of the agent, and then extracted raw data by performing pedestrian based discrete event simulation in the eight prototype example spaces. In addition, the optimal simulation time was derived by analyzing the convergence time of the data within the error range, and we verified the work flow chart through 10 repetitive simulations using samples and agent dependent time analysis. By analyzing the correlation between the density data obtained from the ABM simulation and the result of convex map analysis and the correlation between traffic volume and the result of axial map analysis through Pearson correlation coefficient, the following results were obtained. 1) We confirmed the consistency of the emergence data through 10 repetitive simulations and confirmed that the data converge to within an error range in fast. 2) The convex map has higher correlation than the axial map. 3) Density is significantly influenced by symmetry, and symmetric structure is more correlated than asymmetric structure. The traffic volume is related to the topological features, and the tree topology is more correlated than the ring topology. In particular, the circular structures have no correlation with ABM traffic volume and spatial structure theory. 4) VGA has similar characteristics to space syntax, but the gap was small. Four metrics of space syntax (connectivity, control value, global integration, local integration, connectivity of visual graph analysis) were used as a comparison metric with the spatial structure theory.

교정의사가 선호하는 측모의 유형에 따른 특징적 양상에 관한 연구

김영진,김정환 대한치과교정학회 2001 대한치과교정학회지 Vol.31 No.5

교정 치료의 목표를 설정하는 데에 있어서 여성의 아름다운 측모에 관한 정확한 이해는 필수적인 요소이다. 본 연구에서는 치과교정의사 간에 심미안의 차이가 있는지를 조사하고, 치과교정의사에 의해 선호되는 여성의 심미적인 측모를 선정하여, 이들이 facial convexity의 정도에 따라 심미적인 측모를 구성하기 위한 특징적인 양상을 보이는지를 조사하고자 하였다. 먼저 교육적 배경이 다른 5명의 치과교정의사로 하여금 133명의 20대 여성의 측모 사진을 이용하여 선호도에 따라 심미적인 측모를 채점하도록 하였다. 심미적인 측모를 가졌다고 판정된 35명의 측모 두부 방사선 사진의 투사도를 작성하여 연조직 분석을 시행하였고, 이를 facial convexity의 정도에 따라 convex군(G-Sn-Pg≥9˚)과 straight 군(G-Sn-Pg<9˚)의 두 subgroup으로 세분화하였다. 심미적인 측모를 선정하는 데에 있어서의 객관성 여부를 조사하기 위하여 5명의 치과교정의사 간의 심미안의 차이에 대한 동질성 검정을 시행하였는데 미의 기준이 주관적임에도 불구하고 치과교정의사간에 측모 선호 양상은 통계적으로 유의한 차이가 없었다(p<0.05). 안모 형태의 차이에 따라 세분된 두 subgroup간의 코의 전후 관계를 나타내는 N-Pg-Sn, N-Pg-Pn에서 통계적으로 유의한 차이를 보였고(p<0.05), nasolabial angle, labiomental angle, 그리고 수직적 분석 항목에서 통계적으로 유의한 차이가 없었으며(p<0.05), 상하순 돌출도를 분석한 결과에서 H-angle, Ls to E line, Li to E line, Pg to Sn perp.에서 통계적으로 유의한 차이를 보였으나 Sn-Pg line와 Sn perp. 에서부터의 거리에는 차이가 없었다(p<0.05). 이상의 결과에서 안모 형태(facial pattern)에 따라 심미적인 측모를 구성하기 위한 특징적인 양상의 차이가 존재하며, 이는 특히 코와 상하순, 그리고 턱의 전후방적인 위치에 따라 크게 좌우됨을 알 수 있었다. The perception of facial esthetics is critically important to orthodontists. A viewpoint to facial esthetics is influenced by various factors and dependent on the perception of observer. The purpose of this study was to examine the differences regarding esthetic viewpoints among orthodontists, to identify attractive profiles preferred to orthodontists and to present the characteristic aspects of attractive profiles upon the degree of facial convexity. 35 Persons whose faces were judged as attractive one by 5 orthodontists were selected out of 133 young Korean women. Soft tissue profiles identified as a good-profile group were measured and analyzed. And then according to the facial convexity, good-profile group was subdivided to convex (G-Sn-Pg9˚) and straight (G-Sn-Pg<9˚) groups for the purpose of this study. There were statistically no significant differences regarding esthetic viewpoints among 5 orthodontists(p<0.05), even if there exists prevailing concept that the standard for facial esthetics is substantially subjective. N-Pg-Sn and N-Pg-Pn, measured for determining anteroposterior relationship of midfacial convexity, showed significant differences statistically between 2 subgroups (p<0.05) while nasolabial angle, labiomental angle, and vertical measurements didnt show statistically significant difference between 2 subgroups (p<0.05). And all the measurements related to lip position, H-angle, Ls to E line, Li to E line and Pg to Sn perp., had statistically significant differences between 2 subgroups (p<0.05). The results indicate that the attractive facial profile has different characteristics to be recognized as a good facial pattern, which depend strongly on anteroposterior position of nose, upper and lower lips, and chin.

Quantification of particle shape by an automated image analysis system: a case study in natural sediment samples from extreme climates

주영지,Anastasia M. Soreghan,Megan E. Elwood Madden,Gerilyn S. Soreghan 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.4

Sediment particle shape and microtexture are key parameters utilized for characterizing sediment transport and weathering (both physical and chemical) processes, which in turn are governed by environmental conditions such as climate. Assessing particle shape often involves either qualitative descriptors or time-consuming measurements of shape parameters by a human operator. This study employs a state-of-the-art, quantitative shape analysis instrument known as the “Morphologi G3” from Malvern Instruments, an automated microscope system capable of determining quantitative shape parameters via static image analysis of > 1000 particles in less than two hours. This instrument captures 2D projected images of particles and provides information on grain size measurements such as circle-equivalent diameter, length, width, perimeter, and area, as well as shape parameters such as circularity and convexity. As a case study, we conducted analyses on mud- and sand-sized particles collected from fluvial/alluvial systems of end-member climates to assess variations in sediment particle morphology potentially related to climate and/or transport distance and processes. Sediment samples were collected from fluvial systems in four contrasting climates: hot-arid (southeastern California, USA), hot-humid (eastern Puerto Rico), glacial-arid (proglacial stream of the Dry Valleys, Antarctica), and glacial-humid (Austerdalen proglacial stream, Norway). Results provide quantitative constraints on shape differences that relate to climate and transport, even for very fine-grained sand and mud size fractions. Comparison of the circularity of sediment particles from the four end-member climates indicates that the very fine sand fractions reflect differential physical abrasion and transport processes, whereas the morphology of the mud fraction seemingly imprints chemical weathering processes. We conclude that this new technique has great potential to further document impacts of climate on particle shape with applications to both modern and deep-time depositional systems.

보강토 옹벽의 형상을 고려한 벽체 및 인접지반 거동 연구

이종현(Jong-Hyun Lee),오동욱(Dong-Wook Oh),공석민(Suk-Min Kong),정혁상(Hyuk-Sang Jung),이용주(Yong-Joo Lee) 한국지반신소재학회 2018 한국지반신소재학회 논문집 Vol.17 No.1

최근 보강토 공법은 구조적으로 안정성이 우수하고 경제성이 뛰어나 콘크리트 옹벽을 대체하는 공법으로 많이 사용되고 있으며, 옹벽뿐만 아니라 기초, 사면, 도로 등에 그 적용 범위가 다양하다. 그러나, 우수와 같은 침투수로 인해 전면 벽에서 충분한 안정성을 확보하지 못하여 붕괴, 배부름 현상 등의 피해가 발생할 수 있고, 특히 곡선부에서는 응력집중 현상에 의해 전면 벽의 균열등의 문제가 추가적으로 일어날 수 있다. 이는 보강토 옹벽 곡선부에 대한 정확한 설계 기준이 미흡하고 부실시공을 하는데 원인이 있다고 할 수 있다. 따라서 본 연구에서는 보강토 옹벽의 피해사례를 통해 문제점을 파악하고 유한요소 수치해석을 통해 보강토 옹벽 설계를 위한 기초 연구로서, 옹벽의 형상(볼록형, 오목형)에 따른 직선부와 곡선부의 거동을 비교 · 분석하였다. Recently, GRS (Geosynthetic Retaining Segmental) wall has been widely used as a method to replace concrete retaining wall because of its excellent structural stability and economic efficiency. It has been variously applied for foundation, slope, road as well as retaining wall. The GRS wall system, however, has a weak point that is serious crack of wall due to stress concentration at curved part of it. In this study, therefore, behaviour of GRS wall according to shape of it, shich has convex and concave, are analysed and compared using Finite Element analysis as the fundamental study for design optimization. Results including lateral deflection, settlements of ground surface and wall obtained from 2D FE analysis are compared between straight and curved parts from 3D FE analysis.

Approached Bolza type problems in discrete time

A. Beddani,R. Sahraoui 장전수학회 2017 Proceedings of the Jangjeon mathematical society Vol.20 No.3

Our aim is to give approximate optimality conditions for Bolza type problem in discrete time with …nite dimensional in non- smooth analysis.We have just applied the subdi¤erential calculus of Mordukhovich(see,e.g., [1],[2],[3]) on the one hand and on the other hand, the Ekeland’s variational principle (see,e.g., [20],[21],[22])

The Impact Force of Large Boulders with Irregular Shape in Flash Flood and Debris Flow

Guang-Wu Si,Xiao-Qing Chen,Jian-Gang Chen,Jin-Bo Tang,Wan-Yu Zhao,Ke Jin 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.10

The impact force of large boulders carried by flash floods and debris flows is one of the main causes of structural damage. The elastoplastic modification model of the impact force was derived, and it was found that the impact force was significantly affected by large boulders with irregular shapes. However, a large boulder with an irregular shape is often simplified as an isovolumetric sphere or ellipsoid, which may lead to inaccurate calculation of the impact force. In this paper, a method to obtain the irregular shape of a large boulder in the field is proposed by combining field investigation, image processing, and graphic analysis. The irregular shape is described by a nonuniform rational B-spline (NURBS) curve. The curvature radii corresponding to the potential impact contact points on the surface of a large boulder, which can reflect the influence of the irregular shape, are extracted according to the concavity and convexity analysis. The results demonstrate that NURBS curves can describe irregular shapes both conveniently and accurately. The impact force was corrected by the elastic–plastic model, the impact force increased with increasing curvature radius, and the increase ratio of the impact force gradually decreased with increasing velocity. Compared with the isovolumetric sphere model and ellipsoid model, the impact force calculated by the ellipsoid model is closer to the results obtained in this paper. The reduction factor of the impact force is 0.03 − 0.16, which first increases significantly and then linearly increases with increasing curvature radius. In addition, the reduction factor of the impact force initially exhibits a significant decline with increasing velocity and then gradually stabilises. To simplify parameter selection, we suggest using the maximum curvature radius in the ellipsoid model as the calculation parameter in calculating the impact force of large boulders.

Removability and Stability Analysis Method of Rock Blocks Considering the Persistence of Discontinuities in Tunnels

Hwang, Jae-Yun 한국암반공학회 2006 Geosystem engineering Vol.9 No.3

Block theory is based on the assumption of the infinite persistence of discontinuities, therefore cannot handle a complex concave shaped block. In practice, it is necessary to consider the persistence of discontinuities to attempt applying the block theory to tunnels. In this paper, a new removability and stability analysis method of rock blocks considering the persistence of discontinuities is proposed as a stability evaluation method in tunnels. Three-dimensional rock block identification considering the persistence of discontinuities is performed by using the discontinuity disc model. The removability and stability analyses of rock blocks formed by the identification method are performed. The new analysis method can handle concave and convex shaped rock blocks. In order to demonstrate the applicability of the new removability and stability analysis method of rock blocks considering the persistence of discontinuities in tunnels, two analysis example problems were carried out. The example problems for convex and concave shaped blocks are presented in this study. The comparison and examinations with the analysis results have confirmed the effectiveness and usefulness of this new removability and stability analysis method of rock blocks considering the persistence of discontinuities proposed as a stability evaluation method in tunnels.

Finite element analysis of low-velocity impact response of convex and concave composite laminated shells

Elsevier 2018 COMPOSITE STRUCTURES -BARKING THEN OXFORD- Vol.186 No.-

<P><B>Abstract</B></P> <P>The transient response of composite laminated cylindrical shells with convex and concave shapes, subjected to low-velocity impact, was numerically investigated. Geometrically linear analysis without consideration of the membrane effect demonstrated the same contact force and central deflection histories for convex and concave shells. This unexpected numerical result could be explained by the detailed investigation of all stiffness matrix terms of the finite element equation. Furthermore, in the geometrically linear analysis, the dynamic strain distribution on the top surface of the convex shell exhibited the same contour shapes as those on the bottom surface of the concave shell, with the exception of only a reversed value between the tensile and compressive strains. This unique numerical result could also be explained by the detailed investigation of each term of the strain-displacement relation. Finally, we can conclude that geometrically nonlinear analysis must be performed with consideration of the membrane effect of the curved shell, in order to accurately analyse its impact response.</P>

Sub-Pixel Analysis of Hyperspectral Image Using Linear Spectral Mixing Model and Convex Geometry Concept

Kim, Dae-Sung,Kim, Yong-Il,Lim, Young-Jae Korean Society of Surveying 2004 Korean journal of geomatics Vol.4 No.1

In the middle-resolution remote sensing, the Ground Sampled Distance (GSD) that the detector senses and samples is generally larger than the actual size of the objects (or materials) of interest, and so several objects are embedded in a single pixel. In this case, as it is impossible to detect these objects by the conventional spatial-based image processing techniques, it has to be carried out at sub-pixel level through spectral properties. In this paper, we explain the sub-pixel analysis algorithm, also known as the Linear Spectral Mixing (LSM) model, which has been experimented using the Hyperion data. To find Endmembers used as the prior knowledge for LSM model, we applied the concept of the convex geometry on the two-dimensional scatter plot. The Atmospheric Correction and Minimum Noise Fraction techniques are presented for the pre-processing of Hyperion data. As LSM model is the simplest approach in sub-pixel analysis, the results of our experiment is not good. But we intend to say that the sub-pixel analysis shows much more information in comparison with the image classification.