A study on simplification of SWMM for prime time of urban flood forecasting -a case study of Daerim basin-

Lee, Jung-Hwan,Kim, Min-Seok,Yuk, Gi-Moon,Moon, Young-Il 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.1

도시지역의 모든 하수관망을 사용하여 구축된 강우-유출모형은 그 규모가 방대하고 복잡하여 실시간 도시홍수예보에 적합하지 않다. 따라서 본 연구에서는 상대적으로 도시화가 많이 진행된 서울시의 상습침수지역인 도림천 대림배수분구의 하수관망도를 이용하여 강우-유출모형을 구축하고 이를 단순화하였다. 하수관망 단순화는 노드의 누가유역면적을 단순화의 범위 산정을 위한 기준으로 설정하고 총 5단계의 과정으로 나누었으며 단순화 과정에서 SWMM의 모든 매개변수들을 면적가중치를 적용하여 계산하였다. 또한 하수관망의 적정 단순화 범위를 산정하기 위하여 유출모형에 5가지 단순화 범위를 설정하고 유출분석과 침수분석을 실시하였다. 그 결과, 유출모형의 노드와 관망의 개수 그리고 모의시간 모두 단순화 범위에 따라 50~90%까지 일정하게 감소하였으며 단순화 이전과 동일한 유출량 결과를 나타내었다. 2차원 침수분석의 경우, 누가유역면적별로 단순화의 범위가 커질수록 월류지점의 개수가 크게 감소하고 위치가 바뀌었으나 비슷한 침수양상을 나타내었다. 다만 누가유역면적을 기준으로 6 ha 이상에서는 상류부터 삭제되는 노드에 의해 나타내지 못하는 침수지역이 발생하였다. 2차원 침수면적, 주요침수구간, 침수심 등을 비교 ․ 분석한 결과, 누가유역면적을 기준으로 1 ha의 단순화 범위가 단순화 이전의 분석결과와 가장 유사함을 나타내었다. 본 연구는 SWMM 매개변수를 모두 고려한 하수관망 단순화를 실시함으로써 실시간 도시홍수예보를 위한 신속하고 정확한 유출자료 생성에 활용될 수 있을 것으로 기대한다. The rainfall-runoff model made of sewer networks in the urban area is vast and complex, making it unsuitable for real-time urban flood forecasting. Therefore, the rainfall-runoff model is constructed and simplified using the sewer network of Daerim baisn. The network simplification process was composed of 5 steps based on cumulative drainage area and all parameters of SWMM were calculated using weighted area. Also, in order to estimate the optimal simplification range of the sewage network, runoff and flood analysis was carried out by 5 simplification ranges. As a result, the number of nodes, conduits and the simulation time were constantly reduced to 50~90% according to the simplification ranges. The runoff results of simplified models show the same result before the simplification. In the 2D flood analysis, as the simplification range increases by cumulative drainage area, the number of overflow nodes significantly decreased and the positions were changed, but similar flooding pattern was appeared. However, in the case of more than 6 ha cumulative drainage area, some inundation areas could not be occurred because of deleted nodes from upstream. As a result of comparing flood area and flood depth, it was analyzed that the flood result based on simplification range of 1 ha cumulative drainage area is most similar to the analysis result before simplification. It is expected that this study can be used as reliable data suitable for real-time urban flood forecasting by simplifying sewer network considering SWMM parameters.

도시홍수예보 골든타임확보를 위한 SWMM유출모형 단순화 연구 –대림배수분구를 중심으로-

이정환,김민석,육지문,문영일 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.1

The rainfall-runoff model made of sewer networks in the urban area is vast and complex, making it unsuitable for real-time urban flood forecasting. Therefore, the rainfall-runoff model is constructed and simplified using the sewer network of Daerim baisn. The network simplification process was composed of 5 steps based on cumulative drainage area and all parameters of SWMM were calculated using weighted area. Also, in order to estimate the optimal simplification range of the sewage network, runoff and flood analysis was carried out by 5 simplification ranges. As a result, the number of nodes, conduits and the simulation time were constantly reduced to 50~90% according to the simplification ranges. The runoff results of simplified models show the same result before the simplification. In the 2D flood analysis, as the simplification range increases by cumulative drainage area, the number of overflow nodes significantly decreased and the positions were changed, but similar flooding pattern was appeared. However, in the case of more than 6 ha cumulative drainage area, some inundation areas could not be occurred because of deleted nodes from upstream. As a result of comparing flood area and flood depth, it was analyzed that the flood result based on simplification range of 1 ha cumulative drainage area is most similar to the analysis result before simplification. It is expected that this study can be used as reliable data suitable for real-time urban flood forecasting by simplifying sewer network considering SWMM parameters. 도시지역의 모든 하수관망을 사용하여 구축된 강우-유출모형은 그 규모가 방대하고 복잡하여 실시간 도시홍수예보에 적합하지 않다. 따라서 본 연구에서는 상대적으로 도시화가 많이 진행된 서울시의 상습침수지역인 도림천 대림배수분구의 하수관망도를 이용하여 강우-유출모형을 구축하고 이를 단순화하였다. 하수관망 단순화는 노드의 누가유역면적을 단순화의 범위 산정을 위한 기준으로 설정하고 총 5단계의 과정으로 나누었으며 단순화 과정에서 SWMM의 모든 매개변수들을 면적가중치를 적용하여 계산하였다. 또한 하수관망의 적정 단순화 범위를 산정하기 위하여 유출모형에 5가지 단순화 범위를 설정하고 유출분석과 침수분석을 실시하였다. 그 결과, 유출모형의 노드와 관망의 개수 그리고 모의시간 모두 단순화 범위에 따라 50~90%까지 일정하게 감소하였으며 단순화 이전과 동일한 유출량 결과를 나타내었다. 2차원 침수분석의 경우, 누가유역면적별로 단순화의 범위가 커질수록 월류지점의 개수가 크게 감소하고 위치가 바뀌었으나 비슷한 침수양상을 나타내었다. 다만 누가유역면적을 기준으로 6 ha 이상에서는 상류부터 삭제되는 노드에 의해 나타내지 못하는 침수지역이 발생하였다. 2차원 침수면적, 주요침수구간, 침수심 등을 비교 ․ 분석한 결과, 누가유역면적을 기준으로 1 ha의 단순화 범위가 단순화 이전의 분석결과와 가장 유사함을 나타내었다. 본 연구는 SWMM 매개변수를 모두 고려한 하수관망 단순화를 실시함으로써 실시간 도시홍수예보를 위한 신속하고 정확한 유출자료 생성에 활용될 수 있을 것으로 기대한다.

단위 특징형상 단순화를 이용한 특징형상기반 모델의 점진적 단순화

윤여운(Yeoun Yoon),김병철(Byung Chul Kim) (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.하계

In feature-based simplification, it is important to control the level of detail (LOD) of a CAD model. The LOD in feature-based simplification is affected by the number of features, because the previous methods for feature-based simplification used features as a minimum unit of simplification. It is, therefore, difficult to control the LOD of a CAD model if the model consists of a small number of features or only additive features, or the model contains features with complex shapes. To solve this problem, we propose the unit feature simplification, wherein a feature is progressively simplified. In addition, the implementation and experiment results are presented.

단위 특징형상 단순화를 이용한 개선된 특징형상기반 단순화 방안

윤여운(Yeoun Yoon),김병철(Byung Chul Kim),한승호(Seung Ho Han) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

For engineering activities such as engineering analysis, distributed collaborative design, and virtual prototyping, it is needed to simplify detailed CAD models. Among the proposed methods so far, it is known that feature-based simplification is the most suitable method to apply to these applications. The previous feature-based simplification methods focused on the feature suppression and the feature rearrangement. In case that a feature has complicated shape or a CAD model has only additive features, it is difficult to obtain the proper simplified model because the previous methods perform the simplification by using a feature as a minimum unit. To resolve this problem, we propose an enhanced feature-based simplification method using unit feature simplification. This method simplifies a CAD model by simplifying unit features according to their type. This paper introduces the unit feature simplification method.

자음군단순화와 관련된 몇 문제

최은영 어문연구학회 2013 어문연구 Vol.75 No.-

한국어의 어말자음군은 어말이나 자음 앞에서 두 자음이 모두 실현될 수 없다는 특징을 가지고 있다. 이는 종성에 하나의 자음만 실현되는 음절구조제약에 따른 것으로 이를 자음군단순화라 한다. 이러한 자음군단순화의 실현 양상을 체계적이고 간결하게 규칙화하는 것은 어렵다. 그러므로 본고는 자음군단순화의 규칙을 찾기에 앞서 방언에서 실현되는 자음군단순화의 현상의 특징을 먼저 검토하고자 한다. 한국어의 어말자음군은 크게 ㄹ이 선행하는 자음군과 ㄹ이 아닌 다른 자음이 선행하는 자음군으로 나눌 수 있다. 본고는 ㄹ외의 자음이 선행하는 비ㄹ계 자음군을 자료로 하여 방언에서 어떻게 실현되고 있는지를 검토하였다. 방언의 자료는 제주도를 제외한 8개 지역을 대상으로 하되 한국정신문화연구원의『한국방언자료집Ⅰ~Ⅷ』(1987~1995)에 준하여 논의하였다. 본고는 비ㄹ계자음군단순화와 관련하여 자음군의 방언별 실현 양상을 검토하고 그에 관련하여 특이하게 실현되는 양상을 검토하였다. 방언에서는 기존의 연구와는 다르게 실현되는 양상들이 있다. 크게 후행음절과 관련된 것과 자음군단순화가 두 자음이 아닌 제3의 자음으로 실현되는 경우가 있었다. 후행음절과 관련된 것으로는 두 가지 특이한 실현 양상을 검토하였다. 첫째, ‘ㄳ, ㅄ’ 자음군은 자음이 후행하든 모음이 후행하든지 간에 경음으로 실현되어야 한다. 그러나 경음이 아닌 평음으로 실현되는 양상을 확인하였다. 둘째, ‘ㄶ’ 자음군은 자음이 후행하면 격음으로 실현된다. 그러나 평음으로 실현되는 양상이 있었다. 그리고 어말자음군 다음에 후행하는 음절의 자질을 검토하여 어떠한 양상을 포착할 수 있는지를 확인하였다. 마지막으로 모음이 후행하는 경우 연음이 되어 자음군이 모두 실현되어야 하지만 하나의 자음이 탈락하여 재구조화가 실현되기도 한다. 이러한 재구조화가 방언별로 어느 정도 실현되고 있는지를 검토하였다. 이와 같이 자음군단순화와 관련된 몇 가지의 문제점들을 통하여 자음군단순화의 실현에 대한 특질을 규명하는 데 도움을 주고자 한다. The Korean word final consonant cluster has the feature that both of the two consonants in the coda, Korean word final consonant clusters, shouldn't be pronounced in front of the coda or the consonants in in the initial position. This is why a restriction of only one consonant in the word final consonant cluster having sound by the syllable structure constraints. This rule is called the consonant cluster simplification. It is very hard to make the aspect of the consonant cluster simplification a rule systematically and simply. Therefore I intend to examine the aspects of the consonant cluster simplification which can be seen in dialects in this paper before I try to find the rule for the consonant cluster simplification. The Korean Word final consonant cluster is largely divided into the two groups. One is the consonant cluster starting with ‘ㄹ’. The other is the consonant cluster not starting with ‘ㄹ’. I have examined how the aspects of Korean Word final consonant clusters, especially not starting with ‘ㄹ’ in the word final consonant clusters, appear in dialects, Most of the date dealt with in this paper are from『The Collection of Korean Dialects』(1987~1995), by The Academy of Korean Studies, which are collections of dialect data from 9 districts, namely the whole country. But the date of Je-ju were not studied in this paper. I have found two aspects in those dialects, which the former studies had passed by. One is related with the following syllable, and the other is the case which the consonant cluster simplification appears not with one of the final consonants but with a third consonant. Especially, I've examined the two extraordinary aspects related with the following syllable. First, the consonant cluster ‘ㄳ, ㅄ’ should be sounded into a tense sounds whether they are in front of the consonants or the vowels. But I have found the extraordinary aspects that they are sounded into lax consonants not tense sounds. Second, the consonant cluster ‘ㄶ’ should be sounded into aspirated sounds in front of the consonants. But I have also found the extraordinary aspects that they are sounded with lax consonants. Through Examining the features of the syllables behind the Word final consonant cluster, I have able to catch how the Word final consonant cluster are sounded. Finally, in front of the vowels, the latter one in the Word final consonant cluster should be linked, and then both in the Word final consonant cluster should be pronounced. But I have also found the extraordinary aspect that one of the consonant in the word final consonants is dropped out by the reconstruction. So I have tried to examine how the reconstruction appears in each district except Je-ju. I hope that my research help look into the features of the consonant cluster simplification minutely.

한자의 약자 제정에 대한 고찰

최성엽 ( Choi Sung-yeob ) 동방한문학회 2016 東方漢文學 Vol.0 No.69

The present paper aims to suggest measures for simplifying Chinese letters as a means to solve the issues related to use of traditional Chinese letters of KangxiZidian (康熙字典) calligraphic style. This study was motivated by the Ministry of Education`s declaration to begin using certain number of Chinese letters in the elementary school textbooks starting from 2018. Prior to proposing the principles and methods to simplify the traditional Chinese letters, second thoughts were given here to the needs of such simplification and the proposals and directions already discussed in this regard. It is surely assumed that simplification of Chinese letters will promote the learning effects of Chinese letters, make their use more convenient and help exchanges with neighboring countries to a certain extent. As evidenced in the cases of China and Japan which succeeded in popularizing use of Chinese letters through simplification, we too can expect lots of advantages from simplification of Chinese letters if we could realize it by rectifying and complementing the problems derived in the course of discussions for simplification of Chinese letters. Based on the principles for selecting the Chinese letters to be simplified that have been considered in the meantime, 144 letters were reviewed most of which are identical to or included in the letters and calligraphic styles adopted in Japan and China. Except for some letters, actual use of such simplification could be found in the old Korean as well as in the Chinese literature too. Some controversial letters were excluded from consideration in this paper as they deemed inappropriate to simplify. The new methods to simplify traditional Chinese letters in a standardized and practical manner in compliance with our circumstances are suggested in this study under the following principles: first, to select the Chinese letters which can suit to our reality from among those used already in the simplified form or adopted as popular form; second, to limit the number of Chinese letters to be simplified in around 200 out of 1800 ones designated as ≪Basic Chinese Letters for Teaching Purpose≫; third, to use the simplified Chinese letters only for educational purpose; fourth, to define the simplified Chinese letters just as those which are simplified by more than 3 strokes than the original ones; fifth, to exclude those that have been used in China and Japan in the simplified form, but for those which have solid ground of usage in the old literature; and sixth, to ascertain historical evidence for the hitherto controversial letters for simplification.

Simplification of a Feature-based 3D CAD Assembly Model Considering the Allowable Highest and Lowest Limits of the LOD

Eun-seop Yu(유은섭),Hyunoh Lee(이현오),Soonjo Kwon(권순조),Jeong-youl Lee(이정렬),Duhwan Mun(문두환) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.7

Three-dimensional (3D) computer-aided design (CAD) models require different levels of detail (LODs) depending on their purpose. Therefore, it is beneficial to automatically simplify 3D CAD assembly models to meet the desired LOD. Feature-based 3D CAD assembly models typically have the lowest and highest feasible limits of LOD during simplification. In order to help users obtain a feasible simplification result, we propose a method to simplify feature-based 3D CAD assembly models by determining the lowest and highest limits of LOD. The proposed method is verified through experiments using a simplification prototype implemented as a plug-in type module on Siemens NX.

An Improved Mesh Simplification Algorithm Based on Quadric Error Metrics

Shao-Hui Huang,Bo-liang Wang,Wei-li Wu 대한의료정보학회 2007 Healthcare Informatics Research Vol.13 No.2

Objective: Quadric Error Metrics (QEM) algorithm can simplify complex 3D models. However, for its simple error metrics, QEM is not suitable to simplify medical model that contains many minute detail features. We need to develop a new algorithm because we are often interested in these features. Methods: Based on QEM, We classify the vertex into seven classes. Different class has different cost of collapse. In our algorithm, collapse usually occurs with the lowest cost during simplification, thus minute feature can be preserved as possible. We also introduce the average of correlative triangles' area to estimate the volume change during the simplification. Results: We test our algorithm on several complex medical models and find that our improved algorithm is effective and fast. Conclusion: To simplify a complex medical model, we want to preserve the minute feature during simplification. By classifying the vertexes, we develop an improved algorithm based on QEM. The testing results shows that our algorithm not only maintains the high efficiency of QEM algorithm, but also meets the high requirements of medical image processing on fidelity and mesh quality. (Journal of Korean Society of Medical Informatics 13-2, 165-169, 2007)

체적 보존을 고려한 메쉬 간략화 알고리듬

김종영,장태정 대한전자공학회 2004 電子工學會論文誌-CI (Computer and Information) Vol.41 No.5

본 논문에서는 3D 모델의 체적 보존을 고려하는 메쉬 간략화 알고리듬을 제안하였다. 일반적으로 다른 대부분의 메쉬 간략화 알고리듬에서는 거리 기준을 사용한다. 거리는 기하학적인 오차를 측정하는 매우 효율적인 기준이기는 하지만 거리 기준만을 적용할 경우 원래 모델과 간략화된 모델 간에 체적 변화가 발생한다. 본 논문에서는 원래 모델의 간략화 과정 중에도 체적의 변화가 없는 메쉬 간략화 알고리듬을 제안한다. 본 알고리듬에서는 에지 하나를 줄이면서 체적의 변화가 일어나지 않는 정점 하나를 찾는 방식을 사용한다. 시뮬레이션을 통하여 제안하는 알고리듬이 비록 계산 시간은 좀 더 걸리지만 체적의 변화가 거의 없다는 장점을 가진 것을 확인하였다. In this paper, a mesh simplification algorithm is proposed which considers the conservation of the volume of a 3D model. In General, most of mesh simplification algorithm use a distance metric. The distance metric is very efficient to measure geometric error, but it causes volume changes between the original model and the simplified model. In this paper a mesh simplification algorithm which conserves the volume of the original model is suggested. A new vertex resulting from an edge contraction, takes a position which conserves the volume of the 3D model using the proposed algorithm. Although the new algorithm needs more time than the QEM algorithm, it is shown that it conserves the original volumn of the 3D model during the simplification.

Integral Absolute Mean Curvature를 이용한 다면체 간략화 기법에 관한 연구

김남우(Nam Woo Kim),임우종(Woo Jong Lim),안효민(Hyo Min Ahn),이병국(Byung Gook Lee) 한국컴퓨터게임학회 2004 한국컴퓨터게임학회논문지 Vol.5 No.-

According to Stan Melax's Edge cost formula which is fast and effective but don't fitted for characteric point. The short comings of Stan Melax approach is over come by curvature approach which is fitted for characteric point but it is not so effective. Our proposed formula having advantages of both formula that is simulated with Stan Melax approach and Integral approach. It is simple, effective and fitted for characteric points. 대용량의 데이터를 처리하기 위한 그래픽스 알고리즘을 Simplification이라 하며, Stan Melax의 Edge cost기법은 간결한 수식에 비해 빠르고, 효과적이어서 VRML이나 게임엔진 등에서 널리 응용되어지고 있는 좋은 예이다. 특히, 오늘날 Curvature를 이용한 Simplification방법들이 많이 제안되고 있는데, Edge cost 방법은Curvature를 이용한 Simplification 방법에 비해 각각의 연산수행이 느리고, 특징 점들을 잘 보존하지 못하는 단점이 있다. 본 논문에서는 Integral Absolute Mean Curvature에 Stan Melax의 Edge cost기법을 접목하여, 두 알고리즘의 장점들을 모두 보존할 수 있는 효과적인 Simplification 방법을 제안하고자 한다.