• Title/Summary/Keyword: Shape-similarity

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Numerical Analysis Models for Jointless Bridges Through Sensitivity Analysis (민감도 해석을 통한 무조인트 교량의 수치해석 모델 제안)

  • Noh, Chi-Oug;Kim, Seung-Won;Lee, Hwan-Woo;Nam, Moon-Seok
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.4
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    • pp.255-262
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    • 2021
  • In this study, a jointless bridge that integrates the superstructure and abutment without installing an expansion joint was analyzed. An example of a jointless bridge that has been introduced in Korea since 2009. Owing to the short period of use and lack of experience in design, construction, and maintenance, there is insufficient information regarding the long-term behavior of jointless bridges. When analyzing numerous bridges, the numerical analysis model must maintain the numerical values used and ensure the convenience of model construction. In this study, sensitivity analysis was performed to select a numerical model for various types of jointless bridges using commercial finite element programs, MIDAS Civil and ABAQUS 2018. According to a solid element-based model, we analyzed the mean and maximum relative errors between structural models. Consequently, it was found that the beam element-based model exhibits a significantly small relative error in comparison to the shell element, where a relatively large error was recorded. Therefore, the optimal numerical analysis model, a practical model that maintains the similarity and precision of the displacement shape cause by relative error, was judged to be the most suitable for jointless bridges based on the shell element.

Comparison of Behaviors of Jointless Bridge according to Depth of Abutment Among Numerical Models (수치해석 모델에 따른 무조인트 교량의 교대 깊이별 거동 비교)

  • Kim, Seung-Won;Lee, Hwan-Woo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.3
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    • pp.167-174
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    • 2022
  • This study investigates the behavior of a jointless bridge that integrates superstructure and abutment without an expansion joint. Based on the sensitivity analyses conducted in previous studies, a shell-based model was determined to be the most suitable numerical analysis model for jointless bridges due to the similarity of the model's results compared with the obtained displacement shape, which was influenced by relative errors, precision, and practical aspects. Accordingly, the behavior of a jointless bridge was analyzed at various wall depths using shell element-based and solid element models. In addition, the results of MIDAS Civil and ABAQUS analysis programs were compared. In the case of semi-integrated bridges (A and B), the displacement decreased as the wall depth increased due to the ground reaction force in Case 1 under a linear spring condition and +30℃. In the case where temperature was -30℃, the change in displacement was small because the ground reaction did not occur. As for bridge C (a fully integrated alternating bridge) and bridge D (an integrated chest wall alternating bridge), the displacement decreased as the wall depth increased at both +30 and -30℃ due to pile resistance. As for the comparison between the analysis programs used, the relative error in Case 1 was small, whereas a significant difference in Case 2 was observed. The foregoing variation is possibly due to the difference in the application of the nonlinear spring in the programs.

Object Detection Based on Hellinger Distance IoU and Objectron Application (Hellinger 거리 IoU와 Objectron 적용을 기반으로 하는 객체 감지)

  • Kim, Yong-Gil;Moon, Kyung-Il
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.2
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    • pp.63-70
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    • 2022
  • Although 2D Object detection has been largely improved in the past years with the advance of deep learning methods and the use of large labeled image datasets, 3D object detection from 2D imagery is a challenging problem in a variety of applications such as robotics, due to the lack of data and diversity of appearances and shapes of objects within a category. Google has just announced the launch of Objectron that has a novel data pipeline using mobile augmented reality session data. However, it also is corresponding to 2D-driven 3D object detection technique. This study explores more mature 2D object detection method, and applies its 2D projection to Objectron 3D lifting system. Most object detection methods use bounding boxes to encode and represent the object shape and location. In this work, we explore a stochastic representation of object regions using Gaussian distributions. We also present a similarity measure for the Gaussian distributions based on the Hellinger Distance, which can be viewed as a stochastic Intersection-over-Union. Our experimental results show that the proposed Gaussian representations are closer to annotated segmentation masks in available datasets. Thus, less accuracy problem that is one of several limitations of Objectron can be relaxed.

Seismic Fragility of I-Shape Curved Steel Girder Bridge using Machine Learning Method (머신러닝 기반 I형 곡선 거더 단경간 교량 지진 취약도 분석)

  • Juntai Jeon;Bu-Seog Ju;Ho-Young Son
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.899-907
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    • 2022
  • Purpose: Although many studies on seismic fragility analysis of general bridges have been conducted using machine learning methods, studies on curved bridge structures are insignificant. Therefore, the purpose of this study is to analyze the seismic fragility of bridges with I-shaped curved girders based on the machine learning method considering the material property and geometric uncertainties. Method: Material properties and pier height were considered as uncertainty parameters. Parameters were sampled using the Latin hypercube technique and time history analysis was performed considering the seismic uncertainty. Machine learning data was created by applying artificial neural network and response surface analysis method to the original data. Finally, earthquake fragility analysis was performed using original data and learning data. Result: Parameters were sampled using the Latin hypercube technique, and a total of 160 time history analyzes were performed considering the uncertainty of the earthquake. The analysis result and the predicted value obtained through machine learning were compared, and the coefficient of determination was compared to compare the similarity between the two values. The coefficient of determination of the response surface method was 0.737, which was relatively similar to the observed value. The seismic fragility curve also showed that the predicted value through the response surface method was similar to the observed value. Conclusion: In this study, when the observed value through the finite element analysis and the predicted value through the machine learning method were compared, it was found that the response surface method predicted a result similar to the observed value. However, both machine learning methods were found to underestimate the observed values.

Characteristics of Dioscorea alata L. Introduced from Tropical and Subtropical Regions (도입 마(Dioscorea alata L.)의 특성 분석)

  • Chang, K.J.;Yoo, K.O.;Park, C.H.;Park, J.I.;Hong, K.H.;Park, J.H.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.3 no.1
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    • pp.48-69
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    • 2001
  • A lot of clones of the genus Dioscorea have been introduced from some tropical and subtropical regions since 1997. In 33 clones of water yams (Dioscorea alata L.), some morphological characteristics were investigated at the field. Variation ranges of the total weight and tuber number per stump were within the ranges from 90 to 2,147 g with an average of 610 g ; and 1.3-4.7 with an average of 2.8, respectively. The color tones observed on the tuber-flesh were sorted into 3 color-categories, i.e., white, pale brown and pale purple, and those on leaves were sorted into 3 color-categories, i.e., green, heavy green and purplish green. Intraspecific genetic relationship of 19 variation types of the Yam classified by their external morphological characteristics such as leaf and tuber shape was assessed by DNA using random and specific primers. Twenty two out of 113 primers (100 random[10-mer] primers, two 15 mer [M13 core sequence, and (GGAT)4 sequence]) had been used in PCR-amplification. Only 12 primers, however, were successful in DNA amplification in all of the analyzed plants, resulting in 93 randomly and specifically amplified DNA fragments. The analyzed taxa showed very high polymorphisms(69 bands, 71.0%), allowing individual taxon to be identified based on DNA fingerprinting. Monomorphic bands among total amplified DNA bands of each primer was low under the 50%. Similarity indices between accessions were computed from PCR(polymerase chain reaction) data, and genetic relationships among intraspecific variations were closely related at the levels ranging from 0.66 to 0.90.

Archaeometric Characterization of Raw Materials and Tempers of Bricks Used in the Brick Tombs during Ungjin Period of Baekje (백제 웅진기 벽돌무덤에 사용된 벽돌의 재료와 첨가물 특성 분석)

  • Sungyoon Jang;Hong Ju Jin
    • Economic and Environmental Geology
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    • v.55 no.6
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    • pp.571-582
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    • 2022
  • In this study, the raw material and tempers of bricks used in three brick tombs built in Gongju, during the Ungjin period of Baekje were investigated. The royal tomb of King Muryeong, the 6th tomb in the royal tombs, and Kyochonri brick tomb remained in Gongju and the bricks of each site had different shape and physical properties despite their similarity in raw materials. As the results of the mineralogical and microstructural analysis, the bricks of the royal tombs were made of refined raw materials, and were infrequently added crushed bricks(grogs) as a tempering material. On the other hand, thick and elongated pores of bricks from the Kyochonri brick tomb were frequently found, and the remains of plant carbonization are observed in their microstructures. Since the pores are mainly distributed in a thickness of 0.3 to 1 mm, it is estimated that bricks were produced by adding a certain size of the plant to refined soil, and grogs also were added as a tempering material. In particular, it was found that adding plants and grogs in raw materials of bricks caused thick pores or cracks in the internal structure. Since the bricks of the Kyochonri brick tomb have internal cracks and low firing temperature, the ultrasonic velocity of the bricks was lower than that of the royal tomb bricks. It means that the mechanical strength of these bricks were relatively low. Accordingly, it is estimated that the tempering materials, firing temperature, and internal structures of bricks can affect durability of the brick, and it can be thought as a difference in the manufacturing technology of brick making.

Vertical distribution and vascular plants in the Gakho mountain (Yeongdong-gun), Korea (각호산(영동군)의 관속식물과 수직분포)

  • Jung-Hyun Kim;Jin-Suk Kim;Sookyung Shin;Tae-Im Heo;Young Hoon Kim;Sunghyuk Park;Jin-Seok Kim
    • Korean Journal of Environmental Biology
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    • v.41 no.1
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    • pp.60-88
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    • 2023
  • This study was conducted to investigate the vertical distribution and vascular plants in the Gakho mountain. Form the results of three field surveys from May 2022 to September 2022, a total of 478 total taxa, representing 426 species, 11 subspecies, 35 varieties, four forms, and two hybrids were identified, which were categorized in 282 genera and 94 families. We identified the elevational distribution ranges of 398 taxa of vascular plants. Among them, 19 taxa were endemic to Korea, one taxon was identified as a rare plant. The floristic target plants amounted to 72 taxa, specifically two taxa of grade V, two taxa of grade IV, 16 taxa of grade III, 27 taxa of grade II, and 25 taxa of grade I. Further, 71 taxa were identified as northern lineage plants. A total of 19 taxa of alien plants were identified, with a Naturalized Index of 4.0%, an Urbanization Index of 6.6%, and three plants that disturbed the ecosystem. The result of analyzing the pattern of species richness showed a reversed hump shape with minimum richness at mid-high elevation. A cluster analysis showed a high degree of similarity between adjacent elevation sections that are geographically adjacent with similar habitat environments. Warmth index in the Gakho mountain ranged from 57.2℃·month to 84.2℃·month. Our results provide basic data on vascular plants and valuable information on elevational distribution ranges of current plant species in the Gakho mountain, which could serve as a baseline for comparison of the shifts in elevation under future climate change.

Kidney Tumor Segmentation through Semi-supervised Learning Based on Mean Teacher Using Kidney Local Guided Map in Abdominal CT Images (복부 CT 영상에서 신장 로컬 가이드 맵을 활용한 평균-교사 모델 기반의 준지도학습을 통한 신장 종양 분할)

  • Heeyoung Jeong;Hyeonjin Kim;Helen Hong
    • Journal of the Korea Computer Graphics Society
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    • v.29 no.5
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    • pp.21-30
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    • 2023
  • Accurate segmentation of the kidney tumor is necessary to identify shape, location and safety margin of tumor in abdominal CT images for surgical planning before renal partial nephrectomy. However, kidney tumor segmentation is challenging task due to the various sizes and locations of the tumor for each patient and signal intensity similarity to surrounding organs such as intestine and spleen. In this paper, we propose a semi-supervised learning-based mean teacher network that utilizes both labeled and unlabeled data using a kidney local guided map including kidney local information to segment small-sized kidney tumors occurring at various locations in the kidney, and analyze the performance according to the kidney tumor size. As a result of the study, the proposed method showed an F1-score of 75.24% by considering local information of the kidney using a kidney local guide map to locate the tumor existing around the kidney. In particular, under-segmentation of small-sized tumors which are difficult to segment was improved, and showed a 13.9%p higher F1-score even though it used a smaller amount of labeled data than nnU-Net.

Vertical distribution and vascular plants on Joryeongsan Mountain in Baekdudaegan, Korea (백두대간 조령산의 관속식물과 수직분포)

  • Jung-Hyun Kim;Jin-Suk Kim;Sookyung Shin;Sung-Ae Park;Sunghyuk Park;Sung Kyung Han;Jin-Seok Kim
    • Korean Journal of Environmental Biology
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    • v.42 no.1
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    • pp.95-126
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    • 2024
  • In this study, we investigated the vertical distribution and vascular plants on Joryeongsan Mountain in Baekdudaegan, Korea. The results of four field surveys from April to September 2023 identified a total of 552 taxa, representing 491 species, ten subspecies, 43 varieties, six forms, and two hybrids in 314 genera and 101 families. The elevational distribution ranges of 360 taxa of vascular plants were also identified. Among them, 19 taxa were endemic to Korea, and two taxa were rare plants. The floristic target plants amounted to 100 taxa, specifically two taxa of grade V, seven taxa of grade IV, 25 taxa of grade III, 33 taxa of grade II, and 33 taxa of grade I. Seventy-eight taxa were northern lineage plants. In all, 29 taxa of alien plants were recorded in the investigated area, with a naturalized index of 5.3% and an urbanization index of 7.4%. Two plants disturbed the ecosystem. Species richness along the elevation showed a reversed double-hump shape with peaks at low, mid, and high elevations. The results of a cluster analysis showed a high degree of similarity between adjacent elevation sections, except in lowlands. Detrended Correspondence Analysis ordination also supported distinct groups by elevation. Warmth index values ranged from 62.1℃·month to 92.9℃·month on Joryeongsan Mountain. Our results provide primary data on vascular plants and valuable information on the current distribution ranges of plant species on Joryeongsan Mountain. These data could serve as a baseline for comparing species shifts at elevations under future climate changes.

Digital painting: Image transfonnation, simulation, heterologie and transfonnation (현대회화에서의 형태와 물질 -Digital Transfiguration에 관한 연구-)

  • Jeong, Suk-Yeong
    • Journal of Science of Art and Design
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    • v.10
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    • pp.161-181
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    • 2006
  • The words which appeared in my theoretical study and work are image transformation to digital painting, simulation, heterologie and transfiguration, etc. Firstly, let's look into 'digital era' or 'new media era'. Nowadays, the image world including painting within the rapid social and cultural change, which is called as digital era, is having the dramatic change. Together with the development of scientific technology, large number of events which was deemed to be impossible is happening as real in image world Moreover, these changes in image world is greatly influencing to our life. The word which compresses this change of image world and shows is 'digital'. Digit, which means fingers in Latin, indicates separately changing signal, and to be more narrow, it indicates the continual signal of '0' and ' 1' in computer. The opposite word is 'analogue'. As analogue is the word meaning 'infer' or 'similarity', it indicates the signal or form which continuously changes along the series of time when it is compared to digital. Instead of analogue, digital is embossed as a major ruler along the whole area of our current culture. In whole culture and art area, and in whole generalscience, digital is appearing as it has the modernism and importance. The prefix, 'digital', e.g. digital media, digital culture, digital design, digital philosophy, etc, is treated as the synonym of modernism and something new. This advent of digital results the innovative change to the image world, creates the new beauty experience which we could not experience before, and forecasts the formation of advanced art and expansion of creative area. Various intellectual activities using computer is developing the whole world with making the infrastructure. Computer in painting work immediately accomplishes the idea of painters, takes part in simulation work, contingency such as abrupt reversal, extraction, twisting, shaking, obscureness, overlapping, etc, and timing to stimulate the creativity of painters, and provides digital formative language which enables new visual experience to the audience. When the change of digital era, the image appeared in my work is shown in 'transfiguration' like drawing. The word, 'transfiguration' does not indicate the completed and fixed real substance but indicate endlessly moving and floating shape. Thus, this concept is opposite to the substantial consideration, so that various concepts which is able to replace this in accordance with the similar cases are also exist such as change, deterioration, mutation, deformity of appearance and morphing which is frequently used in computer as a technical word. These concepts are not clearly classified, and variably and complicatedly related. Transfiguration basically means the denial of "objectivity' and '(continual) stagnation' or deviation from those. This phenomenon is appeared through the all art schools of art ever since the realism is denied in the 19th century. It is called as 'deformation' in case of expressionism, futurism, cubism, etc, in the beginning of the century, which its former indication is mostly preserved within the process of structural deviation and which has the realistic limit which should be preserved. On the contrary, dramatic transfiguration which has been showing in the modern era through surrealism is different in the point that dramatic transfiguration tends to show the deterioration and deviation rather than the preservation of indicated object. From this point, transfiguration coming out from morphing using computer deteriorates and hides the reality and furthermore, it replaces the 'reality'. Moreover, transfiguration is closely approached to the world of fake or 'imaginary' simulation world of Baudrillard. According to Baudrillard, the image hides and deteriorates the reality, and furthermore, expresses 'not existing' to 'imaginary' under the name of transfiguration. Certain reality, that is, image which is absent from the reality is created and overflowed, so that it finally replaces the reality. This is simulation as it is said by Baudrillard. In turn, Georges Bataille discusses about the image which is produced by digital technology in terms of heterologie. Image of heterologie is the visual signal which is established with the media. Image of media is to have the continuous characteristics of produce, extinction, and transformation, and its clear boundary between images becomes meaningless. The meaning of composition, excess, violation, etc of digital image is explained to heterological study or heteologie suggested as important meaning of Georges Bataille who is a heretic philosopher. As the form and image of mutation shows the shape in accordance with mechanical production, heterologie is introduced as very low materialism (or bas materialisme), in this theory. Heterologie as low materialism which is gradually changing is developing as a different concept and analysis because of the change of time in the late 20s century beside high or low meaning. Including my image, all images non-standardizes and transforms the code. However, reappearance and non-standardization of this code does not seem to be simple. The problem of transformation caused by transfiguration which appears in my digital drawing painting, simulation, heterologie, etc, are the continual problems. Moreover, the subject such as existence of human being, distance from the real life, politics and social problems are being extended to actual research and various expressing work. Especially, individual image world is established by digital painting transfiguration technique, and its change and review start to have the durability. The consciousness of observers who look at the image is changing the subject. Together with theoretical research, researchers are to establish the first step to approach to various image change of digital era painting through transfiguration technique using our realistic and historical image.

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