• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.915-928
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• 2012

Han River estuary (HRE) is located at the middle of the western coast of Korea, and tidal currents were measured at 4 stations in this estuary during the winter season, and previously observed tide data was analyzed. The results of amplitude ratio of $M_4/M_2$ showed that increasing upward to estuary in the HRE. Tide harmonic constants of relative phase $2M_2-M_4$ represent flood dominance, with under 180 degree. But this method has a limit of analysis that typically based on the non-linear distortion of the tidal current in tidal lagoon system where freshwater discharge is assumed to be relatively small. The results of statistically tidal current data indicated that ebb current velocity would be great unlike tide data. Ebb and flood duration time is calculated by slack time of tidal current showed that ebb duration time is longer than flood. The results of correlation of analysis show high value (0.9) between tidal current stations from Incheon harbor to north entrance of Yeomha channel. We reconstructed to find the reasons for the features of ebb dominance the results of harmonic analysis. As major component ($M_2$) in combination with shallow water component ($M_4$), the tidal curve was presented flood dominance that has a flood current is stronger. However, these curve were changed to ebb dominance add up the non-harmonic components that had ebb direction flow by calculated tidally averaged current. The characteristic of enhancement on ebb is showed around the Yeomha channel in the HRE, because averaged flow which acts seaward such as long-term tidal current components due to non-linear effect and freshwater which overcome the flood current.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.353-361
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• 2013

To analyze the distribution of earthquake-induced strain data in rock masses, statistical analysis was performed on four-directional strain data obtained from a ground movement monitoring system installed in Korea. Strain data related to the 2011 Tohoku-oki earthquake and two aftershocks of >M7.0 in 2011 were used in x-MR control chart analysis, a type of univariate statistical analysis that can detect an abnormal distribution. The analysis revealed different dispersion times for each measurement orientation. In a more comprehensive analysis, the strain data were re-evaluated using multivariate statistical analysis (MSA) considering correlations among the various data from the different measurement orientations. $T_2$ and Q-statistics, based on principal component analysis, were used to analyze the time-series strain data in real-time. The procedures were performed with 99.9%, 99.0%, and 95.0% control limits. It is possible to use the MSA data to successfully detect an abnormal distribution caused by earthquakes because the dispersion time using the 99.9% control limit is concurrent with or earlier than that from the x-MR analysis. In addition, the dispersion using the 99.0% and 95.0% control limits detected an abnormal distribution in advance. This finding indicates the potential use of MSA for recognizing abnormal distributions of strain data.

• Journal of the Korean Society for Library and Information Science
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• v.47 no.3
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• pp.181-205
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• 2013

The purpose of this study is to develop a job-stress scale for librarians who work in university libraries. The study was first conducted by analyzing existing representative job-stress scales that are used domestically and internationally. To understand the characteristic of particular job stress that academic librarians have, the in-depth interview among qualitative research methods was selected, and 15 librarians who work at a 4-year system university libraries participated in this study. Based on the results of the questionnaire survey, the reliability and validity were verified. To analyze the validity, exploratory factor analysis was carried out. To extract factors, principal component analysis was used. To extract factors, principal component analysis was used. For the rotation method, a varimax rotation was applied. A tertiary measurement tool with a total of 46 questions for 11 factors was developed after removing measurement questions that were rejected as a result of the analysis. As a result of factor analysis on the tertiary measurement tool, 11 factors were extracted. Those 11 factors include 'peer relation conflict factor(factor 1)', 'superior-subordinate relation conflict factor (factor 2)', 'work compensation evaluation factor(factor 3)', 'emotional labor factor(factor 4)', 'physical environmental factor(factor 5)', 'employment stability(factor 6)', 'job demand factor(psychological) (factor 7)', 'decision-making and responsibility factor(factor 8)', 'work complexity factor(factor 9)', 'work boundary conflict factor(factor 10)', and 'job demand factor(physical)(factor 11)'.

• The KIPS Transactions:PartB
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• v.12B no.1 s.97
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• pp.9-16
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• 2005

This paper focuses on the study of the face authentication system and the robustness of fact authentication methods under illumination changes. Four different face authentication methods are tried. These methods are as fellows; PCA(Principal Component Analysis), GMM(Gaussian Mixture Modeis), 1D HMM(1 Dimensional Hidden Markov Models), Pseudo 2D HMM(Pseudo 2 Dimensional Hidden Markov Models). Experiment results involving an artificial illumination change to fate images are compared with each other. Face feature vector extraction based on the 2D DCT(2 Dimensional Discrete Cosine Transform) if used. Experiments to evaluate the above four different fate authentication methods are carried out on the ORL(Olivetti Research Laboratory) face database. Experiment results show the EER(Equal Error Rate) performance degrade in ail occasions for the varying ${\delta}$. For the non illumination changes, Pseudo 2D HMM is $2.54{\%}$,1D HMM is $3.18{\%}$, PCA is $11.7{\%}$, GMM is $13.38{\%}$. The 1D HMM have the bettor performance than PCA where there is no illumination changes. But the 1D HMM have worse performance than PCA where there is large illumination changes(${\delta}{\geq}40$). For the Pseudo 2D HMM, The best EER performance is observed regardless of the illumination changes.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.450-455
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• 2002

Cu-cored Sn-Ag solder balls were fabricated by coating pure Sn and Ag on Cu balls. The melting behavior and the solderability of the BGA joint with the Ni/Au coated Cu pad were investigated and were compared with those of the commercial Sn-Ag and Sn-Ag-Cu balls. DSC analyses clarified the melting of Cu-cored solders to start at a rather low temperature, the eutectic temperature of Sn-Ag-Cu. It was ascribed to the diffusion of Cu and Ag into Sn plating during the heating process. After reflow soldering the microstructures of the solder and of the interfacial layer between the solder and the Cu pad were analyzed with SEM and EPMA. By EDX analysis, formation of a eutectic microstructure composing of $\beta$-Sn, Ag$_3$Sn, ad Cu$_{6}$Sn$_{5}$ phases was confirmed in the solder, and the η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer was found to form at the interface between the solder and the Cu pad. By conducting shear tests, it was found that the BGA joint using Cu-cored solder ball could prevent the degradation of joint strength during aging at 423K because of the slower growth me of η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer formed at the solder, pad interface. Furthermore, Cu-cored multi-component Sn-Ag-Bi balls were fabricated by sequentially coating the binary Sn-Ag and Sn-Bi solders on Cu balls. The reflow property of these solder balls was investigated. Melting of these solder balls was clarified to start at the almost same temperature as that of Sn-2Ag-0.75Cu-3Bi solder. A microstructure composing of (Sn), Ag$_3$Sn, Bi and Cu$_{6}$Sn$_{5}$ phases was found to form in the solder ball, and a reaction layer containing primarily η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ was found at the interface with Ni/Au coated Cu pad after reflow soldering. By conducting shear test, it was found that the BGA joints using this Cu-core solder balls hardly degraded their joint shear strength during aging at 423K due to the slower growth rate of the η'-(Au, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer at the solder/pad interface.he solder/pad interface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.903-913
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• 2016

Paris Agreement of Climate Change seem affect to Korea eco-policy. Meanwhile the eco-design for reduce carbon emission have been applied in design phase of construction. However eco-design have applied passively except the project of eco-building system. For reflect eco-component in design, design VE that be appling to basic design and executing design phase of all construction project of over 10 billion should be use. But present applying VE Job Plan is reflecting partly eco-component, so the effect is small. Therefor new eco-VE development that reflect eco-elements to exist VE need. As the result of this study, the concept of environmental cost is defined to accounting. The calculation of the cost was using methods that apply $CO_2$ emission trading price, WTP, carbon productivity concept and carbon tax based on $CO_2$ emission. However, in order to apply eco-friendly VE at design phase, the model of new concept included carbon productivity concept is necessary. The eco-friendly VE model of new concept is model using $CO_2$ emission and potential environmental pollution index (PEPI). This study tried define eco-value model and environmental cost definition that become the major axle of eco-VE.

• Korean Journal of Family Social Work
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• no.23
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• pp.5-42
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• 2008

This research utilized the Grounded Theory and Giorgi's phenomenological research method to analyze the experience of battered women who are maintaining a non-violent marriage relationship. Due to the low accessibility of subjects and the distinctiveness of the topic, I have selected 4 participants and conducted in-depth interviews. As for data analysis results, there were 5 superior component elements and 19 inferior component elements for the experience of maintaining a non-violent marriage relationship and these appeared according to time. Thus, it can be analyzed as follows: 'the vicious cycle stage of violence: caught in a trap,' 'stage of breakaway from vicious violence cycle: making the self-rescue measures,' 'entry to a new track: retrieval of autonomy,' 'stage of forming a non-violence track: preventing the recurrence of the violence,' 'stage of maintaining non-violent track: conversion to non-violent relationship.' This research result will be useful in seeking an effective social welfare intervention plan for successful non-violent relationship in order to help 50% of the battered women from family violence who wish to maintain marriage.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.16-21
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• 2019

This study has its aim to judge both applicability and suitability of recycling of waste soil for the use of farmland amelioration and low-lying farmland reclamation through growth and development experiment and component analysis. As results of physical characteristic evaluation on recycling of waste soil, the classification based on unified soil classification system has investigated as SW and SP affiliation and soil classification has appeared to be a loamy sand. As results of chemical component analysis, pH has appeared to be 7.0~8.4 which is relatively higher than general soil, however, heavy metal has investigated within the 1 region's standard value of soil pollution standards. As results of germination experiment, when using it by mixing recycling soil less than 75%, there is no significant influence on germination, and in the growth and development experiment, when using horticultural bed soil which is mixed with less than 40% of recycling of waste soil, it has confirmed that there is no significance difference with general soil. In case of farmland, the growth disorder of recycling of waste soil rate no more than 40% has shown that it has relatively small influences, and in case of using it by mixing with agricultural soil, it has evaluated to require concrete review of factors which may restrict growth condition including nutrition and pH.

• Management & Information Systems Review
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• v.28 no.4
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• pp.1-26
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• 2009

Among food-service managers, a survey was conducted to grasp the their work-related education conditions and the demand for education program development. This study focuses on food-service managers in web-based training and analyzes the critical factors involved in their learning process in order to clarify the factors that lead to the maximization of training programs. The results of all this study process are as follows. First, the characteristics of web-based education including component of education factor, system factor, deepening learning factor have meaningful effect on commitment of the participants and education performance(except deepening learning factor to education performance). Second, the analysis that the characteristics of individuals including self-efficacy in learning, purpose-directivity factor have meaningful effects on commitment of the participants and education performance(except purpose-directivity factor to education performance). Third, commitment of the participants has meaningful effects on the education performance. Thus, it is advisable for education managers or operators to emphasize in foodservice organizations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.943-952
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• 2006

The OFDM system is very good for the high data rate communication system. However, OFDM system has a high PAPR problem. This makes the OFDM signal distorted through the nonlinear HPA(High Power Amplifier). To solve this problem, generally, simple PAPR reduction methods have been considered. However, in this paper, we introduce IMD reduction method instead of PAPR. PAPR is the signal property and the IMD is signal component of the HPA output, which degrades the communication quality. So, instead of PAPR we want to use the IMD reduction method. This is to transmit a signal with the smallest distortion by considering the third order nonlinearity when the data is recovered. We use the TR method that was proposed for the PAPR reduction and we find out the BER performance of two methods. As results, we show that the IMD reduction method improves better BER performance than the PAPR reduction.