• Structural Engineering and Mechanics
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• v.86 no.6
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• pp.715-730
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• 2023

Broad studies have addressed the issue of structural element damage identification, however, rubber bearing, as a key component of load transmission between the superstructure and substructure, is essential to the operational safety of a bridge, which should be paid more attention to its health condition. However, regarding the limitations of the traditional bearing damage detection methods as well as few studies have been conducted on this topic, in this paper, inspired by the model updating-based structural damage identification, a two-stage bearing damage identification method has been proposed. In the first stage, we deduce a novel bearing damage localization indicator, called element relative MSE, to accurately determine the bearing damage location. In the second one, the prior knowledge of bearing damage localization is combined with sailfish optimization (SFO) to perform the bearing damage estimation. In order to validate the feasibility, a numerical example of a 5-span continuous beam is introduced, also the noise robustness has been investigated. Meanwhile, the effectiveness and engineering applicability are further verified based on an experimental simply supported beam and actual engineering of the I-40 Bridge. The obtained results are good, which indicate that the proposed method is not only suitable for simple structures but also can accurately locate the bearing damage site and identify its severity for complex structure. To summarize, the proposed method provides a good guideline for the issue of bridge bearing detection, which could be used to reduce the difficulty of the traditional bearing failure detection approach, further saving labor costs and economic expenses.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.345-361
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• 2013

Locating and assessing the severity of damage in large or complex structures is one of the most challenging problems in the field of civil engineering. Considering that the wavelet packet transform (WPT) has the ability to clearly reflect the damage characteristics of structural response signals and the artificial neural network (ANN) is capable of learning in an unsupervised manner and of forming new classes when the structural exhibits change, this paper investigates a multi-stage structural damage diagnosis method by using the WPT and ANN based on "energy-damage" theory, in which, the wavelet packet component energies are first extracted to be damage sensitive feature and then adopted as input into an improved back propagation (BP) neural network model for damage diagnosis in a step by step mode. To validate the efficacy of the presented approach of the damage diagnosis, the benchmark structure of the American Society of Civil Engineers (ASCE) is employed in the case study. The results of damage diagnosis indicate that the method herein is computationally efficient and is able to detect the existence of different damage patterns in the simulated experiment where minor, moderate and severe damages corresponds to involving in the loss of stiffness on braces or the removal bracing in various combinations.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1065-1068
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• 2003

The nano imprint process is one of the next generation lithography has been mentioned as one of major nanoreplication techniques because it is simple process, low cost, high replication fidelity and relatively high throughput. This process requires a surface contact between a template with patterns and a wafer on a stage. After contact, the vertical moving the template to the wafer causes some directional motions of the stage. Thus the stage must move according to the motions of the template to avoid the damage of the transferred patterns on the wafer. This study is to develop the wafer stage with a passive compliance to overcome the damage. This stage is designed with the concept like that it has a monolithic, symmetry and planar 6-DOF mechanism.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.81-87
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• 2015

Recently, with the development of the ICT environment, the use of the software is growing rapidly. And the number of the web server software used with a variety of users is also growing. However, There are also various damage cases increased due to a software security vulnerability as software usage is increasing. Especially web shell hacking which abuses software vulnerabilities accounts for a very high percentage. These web server environment damage can induce primary damage such like homepage modification for malware spreading and secondary damage such like privacy. Source code weaknesses checking system is needed during software development stage and operation stage in real-time to prevent software vulnerabilities. Also the system which can detect and determine web shell from checked code in real time is needed. Therefore, in this paper, we propose the system improving security for web server by detecting web shell attacks which are invisible to existing detection method such as Firewall, IDS/IPS, Web Firewall, Anti-Virus, etc. while satisfying existing secure coding guidelines from development stage to operation stage.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.123-128
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• 1982

This study was carried out to investigate the effect of ozone gas on paddy rice at the different growth stage. Seokwang variety of rice plant was exposed to 0.5 ppm ozone gas for 4 hours at rooting, maximum tillering, ear formation and heading stages. after ozone gas fumigation, damage symptom, percentage of destroyed leaf, chlorophyll content and peroxidase activity of rice plant were observed. The results obtained are as follows. 1) Typical symptom of ozone gas damage appeared greyish or reddish brown subtle spots within rice leaf vein. 2) Yield loss by ozone gas exposure at different growth stage was in the order of maximum tillering stage>rooting stage>ear formation stage>heading stage. 3) Chlorophyll damage and leaf destruction was the highest at maximum tillering stage, while damage of leaf and chlorophyll were not found at heading stage. 4) The damage by ozone gas fumigation was higher at the growth stage with higher N content in plant, and N content was decreased after ozone gas exposure.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.291-308
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• 2013

A novel concept of transmissibility based on a wavelet transform for structural damage detection is presented in this paper. The main objective of the research was the development of a method for detecting slight damage at the incipient stage. As a vibration-based approach, the concept of transmissibility has attracted considerable interest because of its advantages and effectiveness in damage detection. However, like other vibration-based methods, transmissibility-based approaches suffer from insensitivity to slight local damage because of the regularity of the traditional Fourier transform. Therefore, the powerful signal processing techniques must be found to solve this problem. Wavelet transform that is able to capture subtle information in measured signals has received extensive attention in the field of damage detection in recent decades. In this paper, we first propose a novel transmissibility concept based on the wavelet transform. Outlier analysis was adopted to construct a damage detection algorithm with wavelet-based transmissibility. The feasibility of the proposed method was numerically investigated with a typical six-degrees-of-freedom spring-mass system, and comparative investigations were performed with a conventional transmissibility approach. The results demonstrate that the proposed transmissibility is more sensitive than conventional transmissibility, and the former is a promising tool for structural damage detection at the incipient stage.

• Transactions of Materials Processing
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• v.8 no.2
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• pp.216-221
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• 1999

In this paper, an application-oriented approach to piercing analysis in automatic forging simulation by the rigid-viscoplastic finite element mehtod is presented. In the presented approach, the accumulated damage is traced and the piercing instant is determined when the accumulated damage reaches the critical damage value. A method of obtaining the critical damage value by comparing the tensile test result with the analysis one is given. The presented approach is verified by experiments and applied to automatic simulation of a sequence of 6-stage forging processes.

• Journal of Ocean Engineering and Technology
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• v.33 no.1
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• pp.33-41
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• 2019

Estimating fatigue damage is a very important issue in the design of ships. The springing and whipping response, which is the hydro-elastic response of the ship, can increase the fatigue damage of the ship. So, these phenomena should be considered in the design stage. However, the current studies on the the application of springing and whipping responses at the design stage are not sufficient. So, in this study, a prediction method was developed using fluid-structural interaction analysis to assess of the fatigue damage induced by springing and whipping. The stress transfer function (Stress RAO) was obtained by using the 3D FE model in the frequency domain, and the fatigue damage, including linear springing, was estimated by using the wide band damage model. We also used the 1D beam model to develop a method to estimate the fatigue damage, including nonlinear springing and whipping by the vertical bending moment in the short-term sea state. This method can be applied to structural members where fatigue strength is weak to vertical bending moments, such as longitudinal stiffeners. The methodology we developed was applied to 325K VLOC, and we analyzed the effect of the springing and whipping phenomena on the existing design.

• Journal of Sasang Constitutional Medicine
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• v.33 no.1
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• pp.1-21
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• 2021

Objective The purpose of this study was to examine the correlation between the Cold-damage Six-meridian disease of Qibo (岐伯六經病證) and Sasang Constitutional Symptomatology (四象體質病證), presented in Discourse on the Origin of Eastern Medicine (醫源論) of Longevity and Life Preservation in Eastern Medicine (Donguisusebowon, 東醫壽世保元). Method The process of development from Cold-damage Six-meridian disease of Qibo (岐伯六經病證) to Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑) was investigated. And the correlation between Six Meridians Physical Symptoms and Medicines (六經形證用藥) and Sasang Constitutional Symptomatology (四象體質病證) was considered. Results and Conclusions 1. The Cold-damage Six-meridian disease of Qibo (岐伯六經病證) in the chapter Heat Treatise (熱論篇) of Basic Questions (素問) had evolved into Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑) through Book for Life Saving (Huorenshu, 活人書), a work of Zhu Gong (朱肱), Six Books on Cold Damage disease (Shanghanliushu, 傷寒六書), a work of Tao Hua (陶華) and Introduction to Medicine (YixueRumen, 醫學入門), a work of Li Chan (李梴). 2. The correlation between the Cold-damage Six-meridian disease of Qibo (岐伯六經病證) and Sasang Constitutional Symptomatology (四象體質病證) can be analyzed and understood through Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑). 3. Greater Yang meridian disease of Qibo (岐伯) is related to Soyangin early stage of Lesser-Yang Wind-Injury symptomatology and Soyangin early stage of Chest-Heat symptomatology, Yang Brightness meridian disease and Greater Yin meridian disease to Taeeumin Liver-Heat symptomatology, Lesser Yin meridian disease to Soyangin Chest-Heat symptomatology, Lesser Yang meridian disease to Soyangin early stage of Lesser-Yang Wind-Injury symptomatology and Reverting Yin meridian disease to Soeumin Reverting Yin symptomatology of Greater Yang disease.

• Computers and Concrete
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• v.31 no.6
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• pp.485-499
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• 2023

Both damage and unsaturated conditions accelerate the transport of erosive media inside concrete. However, their combined effects have not been fully investigated. A multiscale mortar model using representative volume elements is developed, capturing the number and distribution in each phase. Afterwards, mortar damage microstructure evolution is simulated in the tensile process. Finally, the unsaturated mortar transport is predicted and analysed. The results indicate that damage significantly affects the diffusion process in the early stage, while the transport performance is weakened due to the obstruction of the nontransport phase in the later stage. The higher the saturation and the more connected pores, the faster the diffusion rate of chloride ions. Chloride ions spread around the cracks in a tree-like manner along. The model can very well predict the chloride ion transport performance of unsaturated and damaged mortar.