• Title/Summary/Keyword: 이재홍

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Effect of Analysis Method on Seismic Response for a Suspension Bridge (해석방법이 현수교 지진응답에 미치는 영향)

  • 김호경;유동호;이동일;이재홍
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.03a
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    • pp.422-429
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    • 2003
  • A comparative study was performed for a suspension bridge to grasp the possible differences in seismic responses evaluated by several analytical methods. The items mainly investigated are the linear vs. nonlinear response the response spectrum method vs. the linear dynamic analysis method and the damping ratio and it's implementation into analysis procedures. According to the numerical example, it is found that the seismic responses are considerably affected by the damping-related parameters even though slight differences are shown depending on the response quantities md the exciting directions. On the other hand, it is also confirmed that the seismic responses are less affected by the analysis method-related parameters such as the response spectrum method vs. the linear dynamic analysis method, and the linear and nonlinear analysis method. The response spectrum method is expected to give conservative results for the examined bridge, provided that the design response spectrum in the Korean Highway Design Specification is modified according to the proper damping ratio.

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Influence of Cultivated Conditions and Fungicides on Development of Rhizoctonia Diseases of Zoysiagrass and Bentgrass (한국들잔디와 벤트그라스의 라이족토니아 마름병 발생에 미치는 재배조건 및 살균제의 영향)

  • 이재홍;이두형
    • Asian Journal of Turfgrass Science
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    • v.9 no.3
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    • pp.199-206
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    • 1995
  • This study is aimed to clarify on the influence of cultivated conditions and fungicides on development of Rhizoetonia diseases of zoysiagrass and creeping bentgrass and results are as follows. Infection rates of disease were observed more serious when inoculum amounts were higher than low. Effects of the watering intervals on the severity of disease with artificial inoculating conditions, infection rates were higher when two days watering interval for creeping bentgrass and one day interval for zoysiagrass. Disease severity of creeping bentgrass incited by Rhizoetonia solani AG 1 (1A) was grater under conditions of double amounts of nitrogen fertilization. A posi- tive correlation was founded between the pH and disease development. The pots with pH 5 and 8 were significantly more diseased grass than those in which the pH was in 6.5. Mepronil and myclobutanil were extremely effective against brown patch of creeping bentgrass and large patch of zoysiagrass and followed by capro, and tebeonazole. Fenari was inferior effect to both diseases.

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Fabrication of Tensegrity Modules for Spatial Structures (대공간 구조를 위한 텐세그리티 모듈 제작)

  • Lee, Seunghye;Jeong, Jinwoo;Ahn, Seungwhan;Lee, Jaehong
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.3
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    • pp.61-68
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    • 2019
  • A tensegrity module structure is suitable type for spatial structures. Because the tensegrity is composed of set of discontinuous compressive elements (struts) floating within a net of continuous tensile elements (cables), the system can provide the basis for lightweight and strong. However, despite the advantages of tensegrities, design and fabrication of the systems have difficulty because of form-finding methods, pin-connection and the control of prestress. In this paper, the new pin-connection method was invented to make the tensegrity module. The production process and practical implementation of uniformly compressed the tensegrity structures by using a UTM are described. Experiments showed the mechanical response and failure aspects of the tensegrity system.

Damage Detection in Truss Structures Using Deep Learning Techniques (딥러닝 기술을 이용한 트러스 구조물의 손상 탐지)

  • Lee, Seunghye;Lee, Kihak;Lee, Jaehong
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.1
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    • pp.93-100
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    • 2019
  • There has been considerable recent interest in deep learning techniques for structural analysis and design. However, despite newer algorithms and more precise methods have been developed in the field of computer science, the recent effective deep learning techniques have not been applied to the damage detection topics. In this study, we have explored the structural damage detection method of truss structures using the state-of-the-art deep learning techniques. The deep neural networks are used to train knowledge of the patterns in the response of the undamaged and the damaged structures. A 31-bar planar truss are considered to show the capabilities of the deep learning techniques for identifying the single or multiple-structural damage. The frequency responses and the elasticity moduli of individual elements are used as input and output datasets, respectively. In all considered cases, the neural network can assess damage conditions with very good accuracy.

Relay Selection Scheme Using Imperfect CSI in Cognitive Relay Networks With Multiple Primary Users (다수의 1 차 사용자가 존재하는 무선 인지 중계 네트워크에서의 불완전 채널 정보를 이용한 중계기 선택 기법)

  • Lee, Juhyun;Hong, Seung Geun;Lee, Jae Hong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2018.06a
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    • pp.88-89
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    • 2018
  • 본 논문에서는 다수의 1 차 사용자가 존재하는 무선 인지 중계 네트워크를 분석한다. 다수의 1 차 사용자들의 신호는 2 차 사용자에게 간섭으로 작용하고 2 차 사용자들의 신호 또한 1 차 사용자에게 간섭으로 작용하게 된다. 이러한 환경에서 불완전한 채널 정보를 이용하여 최적의 중계기를 선택하는 방법을 제안하고 이때의 2 차 사용자 네트워크에서의 불능 확률을 분석하였다. 또한 모의실험을 통하여 불완전 채널 정보의 상관 계수의 변화에 따른 불능 확률의 변화를 확인하였다.

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Machine Learning Based Strength Prediction of UHPC for Spatial Structures (대공간 구조물의 UHPC 적용을 위한 기계학습 기반 강도예측기법)

  • Lee, Seunghye;Lee, Jaehong
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.4
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    • pp.111-121
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    • 2020
  • There has been increasing interest in UHPC (Ultra-High Performance Concrete) materials in recent years. Owing to the superior mechanical properties and durability, the UHPC has been widely used for the design of various types of structures. In this paper, machine learning based compressive strength prediction methods of the UHPC are proposed. Various regression-based machine learning models were built to train dataset. For train and validation, 110 data samples collected from the literatures were used. Because the proportion between the compressive strength and its composition is a highly nonlinear, more advanced regression models are demanded to obtain better results. The complex relationship between mixture proportion and concrete compressive strength can be predicted by using the selected regression method.

The Effect of Clinical Training in Physical Therapy : Based on Local Area (물리치료과 학생들의 임상실습만족도에 관한 연구 : 일부지역을 중심으로)

  • Kim, Sang-Soo;Seo, Hyun-Kyu;Kim, Byoung-Gon;Lee, Jae-Hong;Kwon, Won-An
    • PNF and Movement
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    • v.10 no.1
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    • pp.19-23
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    • 2012
  • Purpose : This study was investigation of satisfaction in clinical practice of students in a college. Methods : 250 students were participated in this study for 8 weeks though getting results of clinical practice from 1, 2, 3 clinic hospitals. Results : This was for knowing about achievement, It could figure out the increasing achievement the higher satisfaction with education and environment for clinical practice of physical therapy. As a result, whole satisfactions for environment and course or education in clinical practice was higher. Conclusion : This research was not too much higher satisfaction on participated students in clinical practice. So, it needs to suggest to more study for increasing satisfaction on clinical practice.

The Effect of Diaphragmatic Breathing Exercise on Back Pain of an Elementary Schoolchild (복식호흡 운동이 초등학생의 요통에 미치는 영향)

  • Seo, Young-Gyo;Jung, Min-Su;Lee, Jin-Hwan;Min, Dong-Gi;Lee, Jae-Hong
    • PNF and Movement
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    • v.10 no.3
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    • pp.39-44
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    • 2012
  • Purpose : This study aims to analyze the effect of abdominal respiration on back pain of an Elementary Schoolchild. Methods : The data was collected from April 9 to April 27. We analyzed the descriptive statistics and paired t-test by SPSS 12.0 for windows. Results : The results of the study were as follow : The comparison of change in visual analogue scale showed effective differences before and after diaphragmatic breathing exercise. Conclusion : Thus, this study indicates that have a positive effect on Back Pain of an Elementary Schoolchild. Further trials, which give attention to these parts, are needed before any firm conclusions may be made.