• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.13-21
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• 2003

To investigate the safety and stability of a concrete lining, numerous studies have been conducted over the years and several methods have been developed. Most signal processing techniques of NDT have been based on Fourier analysis. However, the application of Fourier analysis to analyze recorded vibrational signal shows results in the frequency domain only, and it is not enough to analyze transient waves precisely. In this study, Wavelet theory was employed for the analysis of non-stationary wave induced by mechanical impact on tunnel concrete lining. The Wavelet transform of transient signals provides a method for mapping the frequency spectrum as a function of time. To verify the availability of Wavelet transform as a time-frequency analysis tool, model experiments have been conducted and the thickness of the concrete lining was estimated based on the proposed theory. From this study, it was found that the contour map by Wavelet transform provides more distinct results than the power spectrum by Fourier transform and it was also found that Wavelet transform was also an effective tool for the analysis of dispersive waves in tunnel concrete linings.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1184-1191
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• 2016

This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA). This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.

• Journal of Ginseng Research
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• v.30 no.3
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• pp.106-111
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• 2006

Adverse changes in individual's biochemistry under heavy metal stress are directly linked with its metabolic activity and health status. The present investigation highlights the differences in protecting role of Panax ginseng extract against mercuric chloride induced alterations in serum proteins. The assessment was based on dividing fifty albino rats into two sets, one for acute and the other for sub-acute study. All the sets had five groups with five albino rats in each i.e. control group, mercuric chloride treated group, Panax ginseng extract treated group, mercuric chloride followed by Panax ginseng extract treated group and Panax ginseng extract followed by mercuric chloride treated group. Mercuric chloride was given orally 0.926 mg/kg body weight for acute set and 0.044 mg/kg body weight for sub-acute set after LD50 (9.26 mg/kg body weight) determination by probitt analysis. 10 mg/kg body weight Panax ginseng extract was given in both acute and sub-acute sets after incorporating safety trials. The control group received tween-20 and distilled water only. The result exhibited significantly reduction (P<0.01) in serum protein, albumin and globulin following mercuric chloride intoxication whereas significant (P<0.01) enhancement in other groups with Panax ginseng extract as an ingredient confirming its protective role. All serum samples were also electrophoresed in 10% SDS with standard marker using discontinuous buffering system. Gradual disappearance of alpha-2 and beta-1 globulin bands from electrophoretic pattern was observed, while a single sharp band was observed between beta-2 and gamma globulin in serum protein pattern of acutely mercuric chloride treated rats. However, this band could not be visualized in sub-acute studies. Panax ginseng extract exhibits a better protection after acute intoxication.

• Fire Science and Engineering
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• v.23 no.5
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• pp.9-16
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• 2009

Chemical products have had an favorable influence on our everyday life, and contributed very much to the development of human culture. According to the rapid change of industry and the development of scientific technique the using chemical products are increasing more and more. Chemical products can have any hazardous property such as flammability or explosiveness. There are occurring many accidents in the international trade due to the different classification and labelling of chemicals produced in various countries. The main purpose of this work is the development of global standard test methods for the chemicals, and the classification and labelling in building block approach by means of the basic technical data. Oxidizing solids, combustible solids, spontaneously combustible materials, water-prohibitive materials, flammable liquids, self-reactive materials and oxidizing liquids have been classification The first Experiment have tested Oxidizing solids of third five. The results have been classified according to the hazard material safety regulation and the UN regulation, and summarized in a data-base.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.347-350
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• 2004

A space radiation analysis has been used to evaluate an ability of electronic equipment boxes or spacecrafts to endure various radiation effects, so it helps design thicknesses of structure and allocate components to meet the radiation requirements. A comparison study of space radiation dose analysis programs SPENVIS Sectoring Tool (SST) and SIGMA II is conducted through some structure cases, simple sphere shell, box and representative satellite configurations. The results and a discussion of comparison will be given. A general comparison will be shown for understanding those programs. The both programs use the same strategy, solid angle sectoring with ray-tracing method to produce an approximate dose at points in representative simple and complex models of spacecraft structures. Also the particle environment data corresponding to mission specification and radiation transport data are used as input data. But there are distinctions between them. The specification of geometry model and its input scheme, the assignment of dose point and the numbers, the prerequisite programs and ways of representing results will be discussed. SST is a web-based interactive program for sectoring analysis of complex geometries. It may be useful for a preliminary dose assessment with user-friendly interfaces and a package approach. SIGMA II is able to obtain from RSICC (Radiation Safety Information Computational Center) as a FOR-TRAN 77 source code. It may be suitable for either parametric preliminary design or detailed final design, e.g. a manned flight or radiation-sensitive component configuration design. It needs some debugs, recompiling and a tedious work to make geometrical quadric surfaces for actual spacecraft configuration, and has poor documentation. It is recommend to vist RSICC homepage and GEANT4/SSAT homepage.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.2
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• pp.47-66
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• 2020

Objectives The purpose of this study is to evaluate the bone healing effect of Dohongsamul-tang (Taohongsiwu-tang; DH) on femur fractured mice. Methods Mice were randomly divided into 4 groups (naive, control, positive control and DH). All groups except naive group were subjected to bone fracture on both hind limb femurs. Naive group received no treatment at all. Control group was fed with normal saline, and positive control group was orally medicated with tramadol. DH-treated group was orally medicated with DH. We analysed the levels of BMP2, COX2, Col2a1, Sox9, Runx2, and Osterix genes on 3, 7 and 14 days after fracture. Alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, total cholesterol, and triglyceride levels were measured for safety assessment. Results In morphological, histological analysis, callus formation process of DH-treated group was faster than the control group. BMP2, Sox9 gene expression were significantly increased at 7 days after fracture compared to the control group. COX2, Col2a1 gene expression were significantly increased at 14 days after fracture compared to the control group. Total cholesterol was significantly increased by DH at 3 days. Triglyceride was significantly decreased by DH at 3, 7 days after fracture compared to the control group. Conclusions Dohongsamul-tang promoted bone healing process after fracture by stimulating the bone regeneration factors. And DH shows no hepatotoxicity, nephrotoxicity and serum lipid abnormality. In conclusion, it seems that DH helps to promote fracture regeneration after bone fracture by regulating gene expressions related to bone repair.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.179-183
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• 2005

The High-tensile steel has been recognized as a promising concept for structural design of light weight transportation systems such as aircraft high speed trains and fast ships. Using the high-tensile steel has been widely used in ship structures, and this enables to reduce the plate thickness. Using the high-tensile steel effectively for a ship hull, the plate thickness becomes thin so that plate buckling may take place. Therefore, precise assessment of the behavior of plate above primary buckling load is important. In this study, examined closely secondary buckling behavior after initial buckling of thin plate structure which operated compressive load according to the various kinds of yield stress with simply supported boundary condition. Analysis method is F.E.M by commercial program(ANSYS V7.1) and complicated nonlinear behaviour can analyze using art-length method about secondary buckling.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.848-853
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• 2004

Regarding to the project SUAV (Smart Unmanned Aerial Vehicle) in KARI (Korea Aerospace Research Institute), several engine configurations has been evaluated. However it's not an easy task to collect all the necessary data of each engine for the analysis. Usually, some kind of modeling technique is required in order to determine the unknown data. In the present paper a qualitative method for reverse engineering is proposed, in order to identify some design patterns and relationships between parameters. The method can be used to estimate several parameters that usually are not provided by the manufacturer. The method consists of modeling an existing engine and through a simulation, compare its transient behavior with its operating envelope. In the simulation several parameters such as thermodynamics, performance, safety and mechanics concerning to the definition of operation-envelope, have been discussed qualitatively. With the model, all engine parameters can be estimated with acceptable accuracy, making possible the study of dependencies among different parameters such as power-turbine total inertia, TIT, take-off time and part load, in order to check if the engine transient performance is within the design criteria. For more realistic approach and more detailed design requirements, it will be necessary to enhance the compressor map first, and more realistic estimated values must be taken into account for intake-loss, bleed-air and auxiliary power extraction. The relative importance of these “unknown” parameters must be evaluated using sensitivity analysis in the future evaluation. Moreover, fluid dynamics, thermal analysis and stress analysis necessary for the resulting life assessment of en engine, will not be addressed here but in a future paper. With the methodology presented in the paper was possible to infer the relationships between operation-envelope and engine parameters.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.87-103
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• 1995

Since being granted permission for self-assessment of the work environment by the Department of Labor in 1992, POSCO's Industrial Hygiene Laboratory has participated in domestic and Foreign Quality Control Programs 8 times and has obtained remarkable results. It has made a lot of effort to be a proficient laboratory with the ability to observe and analyse environmental monitoring data. The summary of results is as follows: 1. POSCO's Industrial Hygiene Laboratory has received a "P(Proficient)" grade from the round 115 to round 119 of AIHA/NIOSH PAT Program for analysis of such metals as lead, cadmium, zinc, and chromium, and also has received a "P(Proficient)" grade from its round 119 of for organic solvent analysis, i,e,. Trichloroethylene(TCE), Carbon Tetr-achloride(CTC), 1,2-Dichloroethane(DCE), 1,1,1-Trichloroethane(MCM), Tetrachloroethylene (PCE), Chloroform(CFM), Benzene(BNZ), toluene(TOL), and O-xylene(OXY). 2. In the Quality Control Evaluation Program performed by the Industrial Health Research Institute,Korea Industrial Safety Corporation, POSCO has passed impressively in the3-metal analysis test for lead, cadmium, cupper, and in the 6 organic solvent analysis test for Benzene(BNZ), toluene(TOL), O-xylene(OXY), Trichloroethylene(TCE) and Methyl isobutyl keton(MIBK), n-Hexane with 2 standard deviations. These analytic techniques should be practically applied to various fields, and reliable results of environmental monitoring should be considered to improve the work environment and to keep workers from occupation related diseases.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.205-213
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• 2019

In a construction site, excavation work has a close relation with temporary earth retaining structure. In order to build the underground structure most effectively in a narrow space, prevent soil relaxation of the external behind ground in excavation work, and maintain a ground water level, it is required to install a temporary earth retaining structure that secures safety. To prevent soil washoff in underground excavation work, the conventional method of temporary earth retaining structure is to make a temporary wall and build the internal support with the use of earth anchor, raker, and struct for excavation work. RSB method that improves the problem of the conventional method is to remove the internal support, make use of two-row soldier piles and bracing, and thereby to resist earth pressure independently for underground excavation. This study revealed that through the field application cases of RSB method and the measurement result, the applicability of the method for installing a temporary earth retaining structure, the assessment result, and displacement all met allowable values of measurement, and that the RSB method, compared to the conventional method, improved constructability and economy.