• Journal of the Korean Geotechnical Society
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• v.22 no.1
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• pp.53-61
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• 2006

Soil liquefaction occurs by complex dynamic interaction between soil particles and pore fluid. Therefore, experimental researches have been widely performed to analyze liquefaction phenomena. In this research, centrifuge tests were performed to analyze the liquefaction behavior of horizontal sand ground. Centrifugal acceleration was 40g and the thickness of model ground was 25cm, which simulates 10m thickness in prototype scale. Viscous fluid was used as pore fluid to remove the time scaling difference between dissipation and dynamic shaking. Test results showed that the dissipation of excess pore pressure is the combined behavior of solidification and consolidation. In addition, the solidification rate, the ground acceleration amplitude, and the dynamic permeability during solidification were influenced by the confining pressure.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.14 no.2
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• pp.110-116
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• 2003

Background and Objectives : Laryngeal cancer discrimination using voice signals is a non-invasive method that can carry out the examination rapidly and simply without giving discomfort to the patients. n appropriate analysis parameters and classifiers are developed, this method can be used effectively in various applications including telemedicine. This study examines voice analysis parameters used for laryngeal disease discrimination to help discriminate laryngeal diseases by voice signal analysis. The study also estimates the laryngeal cancer discrimination activity of the Gaussian mixture model (GMM) classifier based on the statistical modelling of voice analysis parameters. Materials and Methods : The Multi-dimensional voice program (MDVP) parameters, which have been widely used for the analysis of laryngeal cancer voice, sometimes fail to analyze the voice of a laryngeal cancer patient whose cycle is seriously damaged. Accordingly, it is necessary to develop a new method that enables an analysis of high reliability for the voice signals that cannot be analyzed by the MDVP. To conduct the experiments of laryngeal cancer discrimination, the authors used three types of voices collected at the Department of Otorhinorlaryngology, Pusan National University Hospital. 50 normal males voice data, 50 voices of males with benign laryngeal diseases and 105 voices of males laryngeal cancer. In addition, the experiment also included 11 voices data of males with laryngeal cancer that cannot be analyzed by the MDVP, Only monosyllabic vowel /a/ was used as voice data. Since there were only 11 voices of laryngeal cancer patients that cannot be analyzed by the MDVP, those voices were used only for discrimination. This study examined the linear predictive cepstral coefficients (LPCC) and the met-frequency cepstral coefficients (MFCC) that are the two major cepstrum analysis methods in the area of acoustic recognition. Results : The results showed that this met frequency scaling process was effective in acoustic recognition but not useful for laryngeal cancer discrimination. Accordingly, the linear frequency cepstral coefficients (LFCC) that excluded the met frequency scaling from the MFCC was introduced. The LFCC showed more excellent discrimination activity rather than the MFCC in predictability of laryngeal cancer. Conclusion : In conclusion, the parameters applied in this study could discriminate accurately even the terminal laryngeal cancer whose periodicity is disturbed. Also it is thought that future studies on various classification algorithms and parameters representing pathophysiology of vocal cords will make it possible to discriminate benign laryngeal diseases as well, in addition to laryngeal cancer.

• Science of Emotion and Sensibility
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• v.15 no.2
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• pp.283-296
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• 2012

The goal of this study is to determine the social emotion model as an emotion sharing relationship and information sharing relationship based on the user's relations at social networking services. 26 social emotions were extracted by verification of compliance among 92 different emotions collected from the literature survey. The survey on the 26 emotion words was verified to the similarity of social relation types to the Likert 7-points scale. The principal component analysis of the survey data determined 12 representative social emotions in the emotion sharing relation and 13 representative social emotions in the information sharing relation. Multidimensional scaling developed the two-dimensional social emotion model of emotion sharing relation and of information sharing relation based on online communication environment. Meanwhile, insignificant factors in the suggest social emotion models were removed by the structural equation modeling analysis, statistically. The test result of validity analysis demonstrated the fitness of social emotion models at emotion sharing relationships (CFI: .887, TLI: .885, RMSEA: .094), social emotion model of information sharing relationships (CFI: .917, TLI: .900, RMSEA : 0.050). In conclusion, this study presents two different social emotion models based on two different relation types. The findings of this study will provide not only a reference of evaluating social emotions in designing social networking services but also a direction of improving social emotions.

• Journal of Korean society of Dental Hygiene
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• v.10 no.1
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• pp.81-92
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• 2010

Objectives : Thus this study attempted to look into the level of community residents' dental health and the state of their dental diseases and estimate the general dental health condition so that these data can be available as references in upcoming public dental health planning, and to provide fundamental data for promotion of the level of residents' dental health by performing dental health education. Methods : Among community residents who visited the department of Dental Hygiene of Shinsung University for scaling from March to May 2009, the data of total 346 subjects of 129 women and 217 men were selected, and DMFT rate, DMFT index, dental health capacity of the first permanent molar, and tooth morality rate were investigated. For statistical analysis, SPSS 14.0 was used, for general characteristics of the subjects, frequency analysis was conducted, for caries experience in the permanent teeth of the subjects, mean and standard deviation were calculated, for caries experience in the permanent teeth by sex and residence, independent t-test was performed, and for caries experience in the permanent teeth by age, one-way ANOVA was conducted. The significance level applied to these analyses was 0.05. Results : As a result of investigation and analysis on caries in the permanent teeth of community residents who visited the department for scaling in this study, the findings are as follows: 1. For sex, DMFT rate and tooth morality rate were found to be higher in women, while dental health capacity of the first permanent molar was found to be higher in men. 2. For age, DMFT rate and DMFT index were found to be highest in 40~49 years old, while DMFT rate, DMFT index, and tooth morality rate were found to be lowest in under 20 years old. Dental health capacity of the first permanent molar was found to be highest in under 20 years old, 20-29 years old, and 30-39 years old and found to be lowest in more than their sixties as 39.78 points(p<.000). Tooth morality rate was found to be highest in more than their sixties compared to other age groups.(p<.000). 3. For residence, DMFT rate and dental health capacity of the first permanent molar were found to be high in the Metropolitan area, while tooth morality rate was found to be high in Chungcheong area. Conclusions : Seen from the above-mentioned results, great importance shall be attached to the maintenance of residual teeth, and with this, efficient efforts are required to be made for upkeep and promotion of dental health.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.473-485
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• 2019

In this study, we investigated the differences of graph constructed by middle school students in daily-life and scientific contexts according to the views on the nature of scientific measurement. A test consisting of three similar data sets regarding daily-life and scientific contexts was developed, and administered to 151 ninth graders. They were expected to construct proportional, inverse-proportional, and increasing and become constant form of graphs for each data set. Graphs constructed were analyzed in the aspects of constructing a trend line (types of a trend line, interpolation/extrapolation), selecting axes variables, scaling axes, and plotting points. Analyses of the results revealed that the students with set paradigm tended to construct a curved trend line, while those with point paradigm constructed a broken trend line in inverse-proportional graph questions. In the aspects of interpolation/extrapolation, most students with set paradigm performed both interpolation and extrapolation better than those with point paradigm in scientific context. Most students with set paradigm performed both interpolation and extrapolation regardless of contexts, while the proportion of interpolation of those with point paradigm was higher in scientific context than in daily-life context. In selecting axes variables, scaling axes, and plotting dots, there were no statistically significant differences between set and point paradigms. On the bases of the results, educational implications for improving graph construction skills of middle school students are discussed.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.329-334
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• 2012

This study was conducted to investigate the health behavior and the oral health status of workers engaged in a manufacturing business, and to analyze the related factors that affect their number if teeth loss. References for the study involved the materials of 526 individuals whose occupational categories are of a manufacturing business, amongst the survey participants in seven city or gun (county) area including Gyeongsan-si, Gyeongju-si, Mungyeong-si, Chilgok-gun, Yecheon-gun and Sangju-gun for the Community Health Survey (CHS) conducted in 2008. The CHS 2008 was conducted for three months from September to November 2008, and the survey details utilized in the study included the number of loss of teeth and teeth-brushing frequency, which was a part of CHS questionnaires and also additionally included for the study. The analysis with respect to the number of teeth loss on sociodemographic factors, was found to be significantly related to the age, educational status, average monthly income and occupation (p<.01). In the $x^2$-test in terms of the oral health status and the number of teeth loss, it was found that the teeth-brushing after lunch (p<.05) and an experience in an oral examination were statistically significant factors (p<.01). According to the multiple-regression analysis with the number of teeth loss being a dependent variable, the age, educational status, marital status and subjective oral health status were the statistically significant (p<.01). In conclusion, it is important to provide education on the teeth-brushing subjected to workers engaged in a manufacturing business with many dental caries and low educational status, and to recommend a regular scaling as well as to establish policy for creating conditions upon an oral health check-up and a tooth scaling and thus allow the maintenance of an oral health.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.11-21
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• 2020

In this study, we compared the spatio-temporal differences of phytoplankton communities among 4 lakes in the Boseong River basin. Field research was conducted quarterly from 2014 to 2017 for this study. A total of 345 species of phytoplankton were identified including 107 Bacillariophyceae, 175 Chlorophyceae, 27 Cyanophyceae and 36 other phytoplankton taxa. Lake Boseong showed higher species numbers and density of phytoplankton than other lakes (Dunn's test, P<0.01). Bacillariophyceae such as Asterionella formosa, Aulacoseira granulata, Fragilaria crotonensis was dominated in most research periods, whereas Scenedesmus ecornis and Coelastrum cambricum belonging to Chlorophyceae were dominant species on August. The self-organizing map (SOM) classified 3 clusters with 10 × 7 grid and showed spatio-temporal variation of phytoplankton communities based on significant difference among each clusters. Total 31 species of phytoplankton were chosen as a indicator species using indicator species analysis(ISA) and reflected seasonal phytoplankton succession and diversity and density of phytoplankton according to nutrient concentration. Water temperature, Secchi depth, conductivity and DO were identified as important factors affecting the differences of phytoplankton communities in the studied lakes in Boseong River basin using non-metric multidimensional scaling (NMDS).

• Advances in concrete construction
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• v.13 no.3
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• pp.215-221
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• 2022

Considering their similar mass densities, an attempt was made to optimize the mix design of micro-concrete that used barite sand as an aggregate by substituting marble powder (5%, 10%, 20%, 30%, 40%, 50%, 70%), clay brick powder (30%, 50%, 70%), and fly ash (30%, 50%, 70%) for the concrete (by mass) to form specimens for shaking table tests. The test results showed that for these three groups of materials, the substitutions had little effect on the density. The barite sand played a decisive role in the density, and the overall density of the specimens reached approximately 2.9 g/cm³. The compressive strength and elastic modulus decreased with an increase in the substitution rates for the three types of materials. Among them, the 28 day compressive strength values of the 40% and 50% marble powder groups were 11.73 MPa and 8.33 MPa, respectively, which were 58.7% and 70.7% lower than the control group, respectively. Their elastic modulus values were 1.33×10⁴ MPa and 1.42×10⁴ MPa, respectively, which were 39.1% and 35% lower than those of the control group, respectively. The 28 day compressive strength values of the 50% and 70% clay brick powder groups were 13.13 MPa and 5.8 MPa, respectively, which were 53.8% and 79.6% lower than the control group, respectively. Their elastic modulus values were 1.54×10⁴ MPa and 1.19×10⁴ MPa, respectively, which were 29.7% and 45.4% lower than those of the control group, respectively. The 28 day compressive strength values of the 50% and 70% fly ash groups were 13.5 MPa and 7.1 MPa, respectively, which were 52.5% and 75% lower than those of the control group, respectively. Their elastic modulus values were 1.36×10⁴ MPa and 0.95×10⁴ MPa, respectively, which were 37.9% and 56.6% lower than those of the control group, respectively. There was a linear relationship between the 28 day compressive strength and elastic modulus, with the correlation coefficient reaching a value higher than 0.88. The test results showed that the model materials met the high density, low compressive strength, and low elastic modulus requirements for shaking table tests, and the test data of the three groups of different alternative materials were compared and analyzed to provide references and assistance for relevant model testers.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.891-899
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• 2015

The lily symptomless virus (LSV) is the most common virus in Korean native lilies and causes various types of damage to overall plant growth. This study was carried out to investigate the elimination rate of the LSV by the in vitro scale culture (scaling) method in Korean native lilies and to test reinfection rates of the LSV under several field culture conditions of bulb production. Four Korean native lilies (Lilium dauricum, L. distichum, L. lancifolium, and L. maximowitzii) were used and their scales were cultured in vitro for micro-scale formation. The micro-scales were subcultured repeatedly using MS culture medium supplemented with 30 or $90g{\cdot}L^{-1}$ sucrose. The culture conditions were $24{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with 16 hour daylength using fluorescent lamps and maintained at $22{\pm}2^{\circ}C$. The virus-free bulblets were grown for one to three years in the greenhouse and transplanted to the field in October or March. Virus infection rates were investigated by direct tissue blotting immunobinding assays and measurement of chlorophyll and protein contents. Virus-free plants could be obtained from the 5th subculture of micro-scales in L. lancifolium and L. maximowitzii or from primary culture in L. dauricum and L. distichum. LSV-free plants were reinfected during bulb production in the field. Reinfection rates were higher at older bulb ages and under higher planting density. The plants planted in October and at inland Gyeongsan had higher infection rates than those planted in March and at coastal area Pohang. The reinfection rate of L. maximowitzii was higher than those of L. dauricum and L. lancifolium. The LSV-infected plants had lower chlorophyll contents and unchanged protein contents compared to virus-free plants.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.577-594
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• 1999

The major cause of periodontal disease is microorganism in the dental plaque. Gingival sulcular fluid, which is exudate released from the tissue near crevicular epithelium is related with inflammation. The purpose of this study was to evaluate the argon laser efficiency between the clinical index and onset of collagenase of gingival sulcular fluid. Material divided 16 patients into 4 groups. The first control was without treatmemt. The second was with just treatment of argon laser, The third was treated by scaling and root planning and the fourth was treated with both scailing and root planning and argon laser. The level of periocheck test, the index of bleeding, and the depth of periodontal pocket were evaluated from for 128 teeth of 64 anterior teeth and 64 posterior teeth. The results were as follows ; 1. In the score of periocheck test, root planing group(group 3) was significantly reduced more than the group without treatment(group 1) and the argon laser treatment(group 2) for results of 3 days and 7 days. But root planing plus argon laser treatment(group 4) in the 7days after experiment, was significantly reduced than no treatment(group 1) and root planing treatment(group 3)(P<0.05), in the 3 days after experiment, was significantly reduced than root planing(group3)(P<0.05). The score of periocheck test to the root planning group(group 3) were significantly reduced between days1, day3 and day7(P<0.05). Root planning plus argon laser group(group 4) were significantly reduced to 1 or 7days and 3 or 7days(P<0.05). The argon laser group(group 2) didn't show any changes. 2. In the case of sulcus bleeding index, the root planning group(group 3) and root planning plus argon laser group(group 4) were reduced more than without treatment group(group 1)(P<0.05) and sulcus bleeding index in the root planning group(group 3) were reduced more than the argon laser group(group 2)(P<0.05). 3. There wasn't any changes of pocket depth between the control and the experiment group as with experiment periods also.