• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.311-316
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• 2004

For the location estimation in the conventional LPMS(Loose Parts Monitoring System), it is popular to employ a group delay among the acoustic sensors installed within a 3 ft range from the impact source. However, there exists inherent error in determining the arrival time differences of the generated wave group among the neighboring sensors. To overcome this problem in this study, the two dimensional approach has been proposed and applied to effectively estimate the arrival time differences by using a continuous wavelet transform which is one of the linear time-frequency analysis methods. The experiment has been performed to both the plate model and the real steam generator in a nuclear power plant. It is expected that the reliability of the location estimation could be enhanced when the proposed time-frequency method is introduced into the LPMS system.

• Journal of Radiation Industry
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• v.9 no.4
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• pp.181-185
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• 2015

Today the biosafety evaluation, a common problem of vital importance, is based on internationally proved test-systems, standards and techniques. The paradigm of biosafety includes multidisciplinary approach, a combination of physical, chemical and biological tests to monitor the environmental level of pollutants and needs to be improved by modern approaches. The genetic risk of environmental pollutions has long been studied by many researchers. In this study, used was the known sensitive plant test-system, clones of plant Tradescantia (spiderwort) able to detect gene mutations (frequency of mutational events and formation of micronuclei) in combination with chemical and, in some instances, with radiological measurements. In addition, male gametophyte generation of fruit trees was applied as bioindicators of genotoxicity. The obtained results did not show any significant increase along with wind direction. As for the male gametophyte assay, the fertility of the investigated fruit-trees near to NPP did not significantly differ from that of the control point. The influence of the NPP on the male generative system of the investigated taxa of fruit trees for the investigated year was not revealed. The system described needs to be expanded by species of interest (human) as there is a difficulty to transfer the revealed dose correlations to humans. The development of this idea includes various levels: population (epidemiological studies), individual, cellular, molecular (DNA), etc.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.152-157
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• 2021

Stainless steel is a metal that does not generate rust. Due to its excellent workability, economic feasibility, and corrosion resistance, it is used in various industrial fields such as ships, piping, nuclear power, and machinery. However, stainless steel is vulnerable to corrosion in harsh environments. To solve this problem, its corrosion resistance could be improved by electrochemically forming an anodized film on its surface. In this study, 316L stainless steel was anodized at room temperature with ethylene glycol-based 0.1 M NH₄F and 0.1M H₂O electrolyte to adjust the thickness of the oxide film using different anodic oxidation voltages (30 V, 50 V, and 70 V) with time control. The anodic oxidation experiment was performed by increasing the time from 1 hour to 7 hours at 2-hour intervals. Corrosion resistance according to the thickness of the anodic oxide film was observed. Electrochemical corrosion behavior of oxide films was investigated through polarization experiments.

• Geomechanics and Engineering
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• v.24 no.1
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• pp.91-103
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• 2021

This paper concerns with forced dynamic response of thick functionally graded (FG) beam resting on viscoelastic foundation including porosity impacts. The dynamic point load is proposed to be triangle point loads in time domain. In current analysis the beam is assumed to be thick, therefore, the two-dimensional plane stress constitutive equation is proposed to govern the stress-strain relationship through the thickness. The porosity and void included in constituent is described by three different distribution models through the beam thickness. The governing equations are obtained by using Lagrange's equations and solved by finite element method. In frame of finite element analysis, twelve-node 2D plane element is exploited to discretize the space domain of beam. In the solution of the dynamic problem, Newmark average acceleration method is used. In the numerical results, effects of porosity coefficient, porosity distribution and foundation parameters on the dynamic responses of functionally graded viscoelastic beam are presented and discussed. The current model is efficient in many applications used porous FGM, such as aerospace, nuclear, power plane sheller, and marine structures.

• Computers and Concrete
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• v.30 no.2
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• pp.143-150
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• 2022

In this paper, the non-linear mathematical problem is solved via numerical scheme by utilizing shooting method. Brownian diffusion and thermophoresis along mass and heat transfer are accounted for. Non-linear expression is reduced via non-dimensional variables. The simplified ordinary differential equations are tackled by shooting technique. Behavior of distinct influential parameters is investigated graphically and analyzed for temperature and concentration profile. Our finding indicates that temperature profile is enhanced for the thermophoresis, Brownian motion coefficient, Prandtl number, Eckert number and temperature slip parameter. Comparison of numerical technique with the extant literature is made and an acceptable agreement is attained. Graphs are plotted to examine the influence of these parameters.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.175-182
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• 2023

APro, a modularized process-based total system performance assessment framework, was developed at the Korea Atomic Energy Research Institute (KAERI) to simulate radionuclide transport considering coupled thermal-hydraulic-mechanical-chemical processes occurring in a geological disposal system. For reactive transport simulation considering geochemical reactions, COMSOL and PHREEQC are coupled with MATLAB in APro using an operator splitting scheme. Conventionally, coupling is performed within a MATLAB interface so that COMSOL stops the calculation to deliver the solution to PHREEQC and restarts to continue the simulation after receiving the solution from PHREEQC at every time step. This is inefficient when the solution is frequently interchanged because restarting the simulation in COMSOL requires an unnecessary setup process. To overcome this issue, a coupling scheme that calls PHREEQC inside COMSOL was developed. In this technique, PHREEQC is called through the "MATLAB function" feature, and PHREEQC results are updated using the COMSOL "Pointwise Constraint" feature. For the one-dimensional advection-reaction-dispersion problem, the proposed coupling technique was verified by comparison with the conventional coupling technique, and it improved the computation time for all test cases. Specifically, the more frequent the link between COMSOL and PHREEQC, the more pronounced was the performance improvement using the proposed technique.

• Steel and Composite Structures
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• v.45 no.3
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• pp.305-330
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• 2022

This article aims to investigate the static deflection and stress analysis of bi-directional functionally graded porous plate (BDFGPP) modeled by unified higher order kinematic theories to include the shear stress effects, which not be considered before. Different shear functions are described according to higher order models that satisfy the zero-shear influence at the top and bottom surfaces, and hence refrain from the need of shear correction factor. The material properties are graded through two spatial directions (i.e., thickness and length directions) according to the power law distribution. The porosities and voids inside the material constituent are described by different cosine functions. Hamilton's principle is implemented to derive the governing equilibrium equation of bi-directional FG porous plate structures. An efficient numerical differential integral quadrature method (DIQM) is exploited to solve the coupled variable coefficients partial differential equations of equilibrium. Problem validation and verification have been proven with previous prestigious work. Numerical results are illustrated to present the significant impacts of kinematic shear relations, gradation indices through thickness and length, porosity type, and boundary conditions on the static deflection and stress distribution of BDFGP plate. The proposed model is efficient in design and analysis of many applications used in nuclear, mechanical, aerospace, naval, dental, and medical fields.

• Journal of Intelligence and Information Systems
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• v.25 no.3
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• pp.63-88
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• 2019

The goal of this paper is to investigate changes in North Korea's domestic and foreign policies through automated text analysis over North Korea represented in South Korean mass media. Based on that data, we then analyze the status of text mining research, using a text mining technique to find the topics, methods, and trends of text mining research. We also investigate the characteristics and method of analysis of the text mining techniques, confirmed by analysis of the data. In this study, R program was used to apply the text mining technique. R program is free software for statistical computing and graphics. Also, Text mining methods allow to highlight the most frequently used keywords in a paragraph of texts. One can create a word cloud, also referred as text cloud or tag cloud. This study proposes a procedure to find meaningful tendencies based on a combination of word cloud, and co-occurrence networks. This study aims to more objectively explore the images of North Korea represented in South Korean newspapers by quantitatively reviewing the patterns of language use related to North Korea from 2016. 11. 1 to 2019. 5. 23 newspaper big data. In this study, we divided into three periods considering recent inter - Korean relations. Before January 1, 2018, it was set as a Before Phase of Peace Building. From January 1, 2018 to February 24, 2019, we have set up a Peace Building Phase. The New Year's message of Kim Jong-un and the Olympics of Pyeong Chang formed an atmosphere of peace on the Korean peninsula. After the Hanoi Pease summit, the third period was the silence of the relationship between North Korea and the United States. Therefore, it was called Depression Phase of Peace Building. This study analyzes news articles related to North Korea of the Korea Press Foundation database(www.bigkinds.or.kr) through text mining, to investigate characteristics of the Kim Jong-un regime's South Korea policy and unification discourse. The main results of this study show that trends in the North Korean national policy agenda can be discovered based on clustering and visualization algorithms. In particular, it examines the changes in the international circumstances, domestic conflicts, the living conditions of North Korea, the South's Aid project for the North, the conflicts of the two Koreas, North Korean nuclear issue, and the North Korean refugee problem through the co-occurrence word analysis. It also offers an analysis of South Korean mentality toward North Korea in terms of the semantic prosody. In the Before Phase of Peace Building, the results of the analysis showed the order of 'Missiles', 'North Korea Nuclear', 'Diplomacy', 'Unification', and ' South-North Korean'. The results of Peace Building Phase are extracted the order of 'Panmunjom', 'Unification', 'North Korea Nuclear', 'Diplomacy', and 'Military'. The results of Depression Phase of Peace Building derived the order of 'North Korea Nuclear', 'North and South Korea', 'Missile', 'State Department', and 'International'. There are 16 words adopted in all three periods. The order is as follows: 'missile', 'North Korea Nuclear', 'Diplomacy', 'Unification', 'North and South Korea', 'Military', 'Kaesong Industrial Complex', 'Defense', 'Sanctions', 'Denuclearization', 'Peace', 'Exchange and Cooperation', and 'South Korea'. We expect that the results of this study will contribute to analyze the trends of news content of North Korea associated with North Korea's provocations. And future research on North Korean trends will be conducted based on the results of this study. We will continue to study the model development for North Korea risk measurement that can anticipate and respond to North Korea's behavior in advance. We expect that the text mining analysis method and the scientific data analysis technique will be applied to North Korea and unification research field. Through these academic studies, I hope to see a lot of studies that make important contributions to the nation.

• Journal of Korean Academy of Nursing
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• v.7 no.2
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• pp.43-59
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• 1977

The Community Health Service considers the family as a service unit and places the emphasis of its service on the health problems and the nursing needs of the family rather than the individual. From the conceptual point of view that tile community health service is both health maintenance and health promotion of the family, the community health nurse should have a knowledge of the growth and development of the family and be responsible for the comprehensive support of normal family development. The community health nurse often is in a position to make a real contribution to normal family development. In order to investigate the relationship between the areas of nursing need and family development, the following objectives were established 1. To discover the general characteristics of the study population by the stage of family development. 2. To discover specific nursing needs in relation to the family developmental stage, and to determine the intensity of the nursing needs and the ability of the family to cope with these needs. 3. To discover overall family health nursing problems in relation to the family developmental stage and determine the intensity of the nursing need and the problem solving ability of family. Definitions : The family developmental stages as classified by Dually were used stage 1. Married couples(without children) stage 2. Childbearing Families (oldest child birth to 30 months of age) stage 3. Families with preschool children (oldest child 2½-to 6 years) stage 4. Families with schoolchildren (oldest child 6 to 13 years). stage 5. Families with teenagers (oldest child 13 to 20 years) stage 6. Families as launching centers (first child gone to last child′s leaving home). stage 7. Middle- aged parents (empty nest to retirement) stage 8. Aging family member (retirement to death of both spouses) The areas of nursing need were defined as those used in the study, "A Comprehensive Study about Health and Nursing Need and a Social Diagram of the Community", by tile Nursing research Institute and Center for population. and Family Planning, July 1974. The study population defiled and selected were 260 nuclear families ill two myron of Kang Hwa Island. Percent, mean value and F- test were utilized in tile statistical analysis of the study result. Findings : 1. General characteristics of the study population by tile family developmental stage ; 1)The study population was distributed by the family developmental stage as follows : stage 1 : 3 families stage 2 : 13 families stage 3 : 24 families stage 4 : 41 families stage 5 : 50 families stage 6 : 106 families stage 7 : 13 families stage 8 : 10 families 2) Most families had 4 or 5 members except for those in stage, 1, 7, and 8. 3) The parents′ present age was older in the higher developmental stage and their age at marriage was also younger in the higher developmental stages. 4) The educational level of parents was primarily less than elementary school irrespective of the developmental stage. 5) More than half of parents′ occupations were listed as laborers irrespective of the developmental stage, 6) More than half of the parents were atheists irrespective of the developmental stage. 7) The higher the developmental stage(from stage 2 to stage 6 ), the wider the distribution of children′s ages. 8) More than half of the families were of middle or lower socio-economic level. 2. Problems in specific areas of nursing need by family developmental stage, the intensity of nursing need and the problem solving ability of the family : 1) As a whole, many problems, irrespective of the developmental stage, occurred in tile areas of Housing and Sanitation, Eating Patterns, Housekeeping, Preventive Measures and Dental care. Problems occurring ill particular stages included the following ; stage 1 : Prevention of Accident stage 2 : Preventive Vaccination, Family Planning. stage 3 : Preventive Vaccination, Maternal Health, Family Planning, Health of Infant and Preschooler. stage 4, 5 : Preventive Vaccination, Family Planning, Health of School Children. stage 6 : Preventive Vaccination, Health of School Children. 2) The intensity of the nursing need in the area of Acute and Chronic Diseases was generally of moderate degree or above irrespective of the developmental stages except for stage 1. Other areas of need listed as moderate or above were found in the following stages: stage 1 : Maternal Health stage 3 . Horsing and Sanitation, Prevention of Accident. stage 4 . Housing and Sanitation. stage 5 : Housing and Sanitation, Diagnostic and Medical Care. stage 6 : Diagnostic and Medical care stage 7 : Diagnostic and Medical Care, Housekeeping. stage 8 : Housing and Sanitation, Prevention of Accident, Diagnostic and Medical Care, Dental Care, Eating Patterns, Housekeeping. 3) Areas of need with moderate problem solving ability or less were as follows : stage 1 : Diagnostic and Medical Care, Maternal Health. stage 2 : Prevention of Accident, Acute and Chronic Disease, Dental Care. stage 3 : Housing and Sanitation, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measure, Dental Care, Maternal Health, Health of Infant and preschooler, Eating Patterns. stage 4 : Housing and Sanitation, Prevention of Accident, Diagnostic and Medical Care, Preventive Measure, Dental Care, Maternal Health, Health of New Born, Health of Infant and Preschooler, Health of school Children, Eating Patterns, Housekeeping. stage 5 . Housing and Sanitation, Prevention of Accident, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measure, Dental Care, Preventive Vaccination, Maternal Health, Eating Patterns. stage 7, 8 : Housing and Sanitation, Prevention of Accident, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measures, Dental Care, Preventive Vaccination, Eating Patterns , Housekeeping. Problem occurrence, the degree of nursing need and the degree of problem solving ability 1 nursing need areas for the family as a whole were as follows : 1) The higher the stages(except stage 1 ), the lower the rate of problem occurrence. 2) The higher the stage becomes, the lower the intensity of the nursing need becomes. 3) The higher the stages (except stages 7 and 8), the higher. the problem solving ability. Conclusions ; 1) When the nursing care plan for the family is drawn up, depending upon the stage of family development, higher priority should be give to nursing need areas ① at which problems were shown to occur ② where the nursing need is shown to be above moderate degree and ③ where the problem solving ability was shown to be of moderate degree. 2) The priority of the nursing service should be Placed ① not on those families in the high developmental stage but on those families in the low developmental stage ② and on those areas of need shown in stages 7 and 8 where the degree nursing need was high and the ability to cope low.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.102-109
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• 2009

Purpose: Flash 3D (pixon(R) method; 3D OSEM) was developed as a software program to shorten exam time and improve image quality through reconstruction, it is an image processing method that usefully be applied to nuclear medicine tomography. If perfoming brain diamox perfusion scan by reconstructing subtracted images by Flash 3D with shortened image acquisition time, there was a problem that SNR of subtracted image is lower than basal image. To increase SNR of subtracted image, we use LEAP collimators, and we emphasized on sensitivity of vessel dilatation than resolution of brain vessel. In this study, our purpose is to confirm possibility of application of LEAP collimators at brain diamox perfusion tomography, identify proper reconstruction factors by using Flash 3D. Materials and methods: (1) The evaluation of phantom: We used Hoffman 3D Brain Phantom with $^{99m}Tc$. We obtained images by LEAP and LEHR collimators (diamox image) and after 6 hours (the half life of $^{99m}Tc$: 6 hours), we use obtained second image (basal image) by same method. Also, we acquired SNR and ratio of white matters/gray matters of each basal image and subtracted image. (2) The evaluation of patient's image: We quantitatively analyzed patients who were examined by LEAP collimators then was classified as a normal group and who were examined by LEHR collimators then was classified as a normal group from 2008. 05 to 2009. 01. We evaluate the results from phantom by substituting factors. We used one-day protocol and injected $^{99m}Tc$-ECD 925 MBq at both basal image acquisition and diamox image acquisition. Results: (1) The evaluation of phantom: After measuring counts from each detector, at basal image 41~46 kcount, stress image 79~90 kcount, subtraction image 40~47 kcount were detected. LEAP was about 102~113 kcount at basal image, 188~210 kcount at stress image and 94~103 at subtraction image kcount were detected. The SNR of LEHR subtraction image was decreased than LEHR basal image about 37%, the SNR of LEAP subtraction image was decreased than LEAP basal image about 17%. The ratio of gray matter versus white matter is 2.2:1 at LEHR basal image and 1.9:1 at subtraction, and at LEAP basal image was 2.4:1 and subtraction image was 2:1. (2) The evaluation of patient's image: the counts acquired by LEHR collimators are about 40~60 kcounts at basal image, and 80~100 kcount at stress image. It was proper to set FWHM as 7 mm at basal and stress image and 11mm at subtraction image. LEAP was about 80~100 kcount at basal image and 180~200 kcount at stress image. LEAP images could reduce blurring by setting FWHM as 5 mm at basal and stress images and 7 mm at subtraction image. At basal and stress image, LEHR image was superior than LEAP image. But in case of subtraction image like a phantom experiment, it showed rough image because SNR of LEHR image was decreased. On the other hand, in case of subtraction LEAP image was better than LEHR image in SNR and sensitivity. In all LEHR and LEAP collimator images, proper subset and iteration frequency was 8 times. Conclusions: We could archive more clear and high SNR subtraction image by using proper filter with LEAP collimator. In case of applying one day protocol and reconstructing by Flash 3D, we could consider application of LEAP collimator to acquire better subtraction image.