• Korean Journal of Social Welfare
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• v.57 no.3
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• pp.305-335
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• 2005

This paper is a result from validation study for SPDA(A Screening Scale For Potential Drug-use Adolescents) created in 2003 and newly developed during 2004. SPDA aims to screen adolescents in their early stage of drug-use and to help practitioners make a preventive approach for the adolescents. 4307 junior and senior high school students were selected as primary research subjects by stratified and quota sampling methods. 305 adolescents on probation were also selected as a comparison group and asked to answer the same questionnaire. Reliability for SPDA recorded 0.914, which proved to be better than previous year's (0.898). Exploratory and confirmatory factor analyses to test construct validity proved that SPDA could be divided into 7 factors and that each factor structure of SPDA could be a proper measurement model with high level of fitness and factor loadings. Discriminant analysis to test predictive validity confirmed that SPDA could classify the adolescents excellently by the frequency of drug-use, with hit ratio of 86.6 percent(78.8% and 87.4% for junior and senior high school students respectively). For concurrent validity test, Hare Home Self-Esteem Scale, Hare School Self-Esteem, Zuckerman-Kuhlman Sensation-seeking Scale were employed to find correlation with SPDA and all the three scales had significant Pearson correlation coefficients with SPDA. Known-groups validity test indicated that SPDA had an adequate power to classify out adolescents on probation from those in schooling, with a hit ratio of 71.8 percent. Cut-off point to detect adolescents with high risk of substance use was 77, which indicated approximately T score, 55 (0.5 SD), satisfying sensitivity, specificity, and efficiency criteria.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.333-343
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• 2015

This research aims at identifying the goshawk's possible and replaceable breeding ground by using the MaxEnt prediction model which has so far been insufficiently used in Korea, and providing evidence to expand possible protection areas for the goshawk's breeding for the future. The field research identified 10 goshawk's nests, and 23 appearance points confirmed during the 3rd round of environmental research were used for analysis. 4 geomorphic, 3 environmental, 7 distance, and 9 weather factors were used as model variables. The final environmental variables were selected through non-parametric verification between appearance and non-appearance coordinates identified by random sampling. The final predictive model (MaxEnt) was structured using 10 factors related to breeding ground and 7 factors related to appearance area selected by statistics verification. According to the results of the study, the factor that affected breeding point structure model the most was temperature seasonality, followed by distance from mixforest, density-class on the forest map and relief energy. The factor that affected appearance point structure model the most was temperature seasonality, followed by distance from rivers and ponds, distance from agricultural land and gradient. The nature of the goshawk's breeding environment and habit to breed inside forests were reflected in this modeling that targets breeding points. The northern central area which is about $189.5 km^2$(2.55 %) is expected to be suitable breeding ground. Large cities such as Cheongju and Chungju are located in the southern part of Chungcheongbuk-do whereas the northern part of Chungcheongbuk-do has evenly distributed forests and farmlands, which helps goshawks have a scope of influence and food source to breed. Appearance point modeling predicted an area of $3,071 km^2$(41.38 %) showing a wider ranging habitat than that of the breeding point modeling due to some limitations such as limited moving observation and non-consideration of seasonal changes. When targeting the breeding points, a specific predictive area can be deduced but it is difficult to check the points of nests and it is impossible to reflect the goshawk's behavioral area. On the other hand, when targeting appearance points, a wider ranging area can be covered but it is less accurate compared to predictive breeding point since simple movements and constant use status are not reflected. However, with these results, the goshawk's habitat can be predicted with reasonable accuracy. In particular, it is necessary to apply precise predictive breeding area data based on habitat modeling results when enforcing an environmental evaluation or establishing a development plan.

• Journal of Korean Home Economics Education Association
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• v.33 no.1
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• pp.1-16
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• 2021

The purpose of this study was to investigate the needs of middle school students for the practical reasoning in a distance learning environment, to verify the needs differences based on the learner's personal characteristics, student-teacher interaction, and student-student interaction, and to investigate the relationships among student-teacher interaction, voluntary participation of students, and the students' perception of the extent to which practical reasoning is implemented in distance learning. For this purpose, 1,842 middle school students from seven schools in Gyeonggi, Daejeon, Chungbuk, and Sejong areas were surveyed online to investigate the importance of the practical reasoning questions and the how much practical reasoning is implemented in current distance learning. Among them, 1,095 responses were used for final analysis and descriptive statistics, independent sample t-test, one-way ANOVA, and path analysis were conducted. As a result of the study, first, middle school students acknowledged that the practical reasoning was important with the importance average 3.76. Based on the locus for focus model, the priorities of the needs in home economics class were examined, and the values and importance of the problem, and the ramification of the solution were considered to be of high priority. Second, characteristics of middle school students, student-teacher interaction and student-student interaction were found to have positive influence on needs for practical reasoning, while no difference were found by gender or voluntary participation in distance learning. Third, the voluntary participation of students and the student-teacher interaction in distance learning had a positive (+) significant effect on perceived implementation of practical reasoning, yet negative (-) significant effect on needs for practical reasoning.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.221-234
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• 2020

The role of entrepreneurship has become important for the continuous growth (scale-up) of companies in a rapidly changing economic environment. However, research has focused mainly on business-oriented growth that emphasizes efficiency only. However, in the era of the fourth industrial revolution, people have become more important than corporate efficiency. In particular, there are few studies on SMEs. The purpose of this study is to investigate how the characteristics of human - centered organizational culture affects the business ecosystem and firm excellence of SMEs, and how business ecosystem and firm excellence affect the performance of corporations. Therefore, this study focuses on the empathy, enablement, empowerment, and engagement of the corporate culture characteristics of the enterprise and the effects of the independent variables on the business ecosystem and the flower excellence as the parameters and the business ecosystem and company excellence. The main research subjects are the causality analysis that examines the effects on the management performance. The results of the study are as follows. Empathy, enablement, empowerment, engagement have a significant impact on the business ecosystem. In addition, the engagement have a positive effect on firm excellence. The results of empirical studies on the causal relationship between business ecosystem, corporate competence, and company excellence and business performance show that business ecosystem has no statistically significant effect on business performance. Corporate excellence has a significant effect on business performance Respectively. In addition to the above findings, this study can suggest the following implications. First, it is an empirical study of small and medium-sized enterprises (SMEs) by utilizing people-oriented entrepreneurship in addition to existing research. Small and medium-sized enterprises (SMEs) are expected to have lower perceptions of people-oriented management than large corporations or public institutions, but the analysis shows that people-centered entrepreneurship has a significant impact on the business ecosystem. Second, the research results of the serial multiple mediating effect analysis show that the higher the atmosphere of entrepreneurship in a company, the higher the atmosphere of entrepreneurship, and the parameters of business ecosystem and company excellence in the effect of people-oriented entrepreneurship on management performance. It is that the path through which people-oriented entrepreneurship influences management performance was verified by verifying the mediating effect by inputting. Lastly, it is hoped that research on people-oriented entrepreneurship in Korea's SMEs will be activated, providing a theoretical basis for transforming SMEs' business models into innovative types.

• Journal of the Korean earth science society
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• v.33 no.2
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• pp.139-147
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• 2012

Mongolia's solar-meteorological resources map has been developed using satellite data and reanalysis data. Solar radiation was calculated using solar radiation model, in which the input data were satellite data from SRTM, TERA, AQUA, AURA and MTSAT-1R satellites and the reanalysis data from NCEP/NCAR. The calculated results are validated by the DSWRF (Downward Short-Wave Radiation Flux) from NCEP/NCAR reanalysis. Mongolia is composed of mountainous region in the western area and desert or semi-arid region in middle and southern parts of the country. South-central area comprises inside the continent with a clear day and less rainfall, and irradiation is higher than other regions on the same latitude. The western mountain region is reached a lot of solar energy due to high elevation but the area is covered with snow (high albedo) throughout the year. The snow cover is a cause of false detection from the cloud detection algorithm of satellite data. Eventually clearness index and solar radiation are underestimated. And southern region has high total precipitable water and aerosol optical depth, but high solar radiation reaches the surface as it is located on the relatively lower latitude. When calculated solar radiation is validated by DSWRF from NCEP/NCAR reanalysis, monthly mean solar radiation is 547.59 MJ which is approximately 2.89 MJ higher than DSWRF. The correlation coefficient between calculation and reanalysis data is 0.99 and the RMSE (Root Mean Square Error) is 6.17 MJ. It turned out to be highest correlation (r=0.94) in October, and lowest correlation (r=0.62) in March considering the error of cloud detection with melting and yellow sand.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.165-174
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• 2010

The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

• Computational Structural Engineering
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• v.7 no.3
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• pp.95-103
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• 1994

The safety related components in the nuclear power plant should be designed to withstand the seismic load. Among these components the integrity of reactor internals under earthquake load is important in stand points of safety and economics, because these are classified to Seismic Class I components. So far the modelling methods of reactor internals have been investigated by many authors. In this paper, the dynamic behaviour of reactor internals of Yong Gwang 1&2 nuclear power plants under SSE(Safe Shutdown Earthquake) load is analyzed by using of the simpled Global Beam Model. For this, as a first step, the characteristic analysis of reactor internal components are performed by using of the finite element code ANSYS. And the Global Beam Model for reactor internals which includes beam elements, nonlinear impact springs which have gaps in upper and lower positions, and hydrodynamical couplings which simulate the fluid-filled cylinders of reactor vessel and core barrel structures is established. And for the exciting external force the response spectrum which is applied to reactor support is converted to the time history input. With this excitation and the model the dynamic behaviour of reactor internals is obtained. As the results, the structural integrity of reactor internal components under seismic excitation is verified and the input for the detailed duel assembly series model could be obtained. And the simplicity and effectiveness of Global Beam Model and the economics of the explicit Runge-Kutta-Gills algorithm in impact problem of high frequency interface components are confirmed.

• Korean Journal of Remote Sensing
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• v.24 no.6
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• pp.551-558
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• 2008

It is well known that the protein content of rice grain is an indicator of taste of cooked rice in the countries where people as the staple food. Ground-based optical sensing over the crop canopy would provide information not only on the mass of plant body which reflects the light, but also on the crop nitrogen content which is closely related to the greenness of plant leaves. The vegetation index has been related to crop variables such as biomass, leaf nitrogen, plant cover, and chlorophyll in cereals. The objective of this study was to investigate the correlation between GNDVI and NDVI values, and grain protein content at different dates and to estimate the grain protein content using G(NDVI) values. We measured Green normalized difference vegetation index [$GNDVI=({\rho}0.80{\mu}m-{\rho}0.55{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.55{\mu}m)$] and [$GNDVI=({\rho}0.80{\mu}m-{\rho}0.68{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.68{\mu}m)$] by using two different active sensors. The study was conducted during the rice growing season for three years from 2005 through 2007 at the experimental plots of National Institute of Agricultural Science and Technology. The experiments were carried out by randomized complete block design with the application of four levels of nitrogen fertilizers(0, 70, 100, 130kg N/ha) and the same amount of phosphorous and potassium content of the fertilizers. After heading stage, relationships between GNDVI of rice canopy and grain protein content showed the highly positive correlation at different dates for three years. GNDVI values showed higher correlation coefficients than that of NDVI during growing season in 2005-07. The correlation between GNDVI values at different dates and grain protein contents was highly correlated at early July. We attempted to estimate the grain protein content at harvesting stage using GNDVI values from early July for three years. The determination coefficients of the linear model by GNDVI values were 0.9l and the measured and estimated grain protein content at harvesting stage using GNDVI values highly correlated($R^2=0.96^{***}$). Results from this study show that GNDVI appeared very effective to estimate leaf nitrogen and grain protein content of rice canopy.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.384-397
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• 2018

The aim of this study is to screen the strains of Bacillus spp. possessing safety, probiotic activity, and so on, which can be utilized as probiotic resource for using the feed and supplement food of companion animal. About 300 isolates were isolated from traditional Korean sauces, four isolates that did not have or produce the six kinds of B. cereus type vomiting and diarrhea toxin genes, ${\beta}$-hemolytic, and three kinds of carcinogenic enzymes were selected. Antibiotic gene retention, cell surface hydrophobicity, antibiotic sensitivity, and glucose utilization were analyzed for four isolates, and finally SRCM 100731 was selected. SRCM 100731 was named as Bacillus amyloliquefaciens SRCM 100731 16S rRNA sequencing analysis, and carried out optimization of cell growth for industrial applications such as pet food and feed. The effects of 14 different components on cell growth were investigated and three significant positive factors, molasses, sodium chloride, and potassium chloride were selected as the main factors based on a Plackett-Burman design. In order to find out optimal concentration on each constituent, we carried out central composite design. The predicted optimized concentrations were 7% molasses, 1.1% sodium chloride, 0.5% potassium chloride. Finally, an overall about 7-fold increase in dry cell weight yield ($12.6625{\pm}0.0658g/L$) was achieved using the optimized medium compared with the non-optimized medium ($1.8273{\pm}0.0214g/L$). This research is expected to be highly utilized in the growing pet industry by establishing optimal cultivation conditions for industrial application as well as screening Bacillus amyloliquefaciens SRCM 100731 as probiotic resource for companion animal.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.9-18
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• 2024

The importance of active sonar systems is emerging due to the quietness of underwater targets and the increase in ambient noise due to the increase in maritime traffic. However, the low signal-to-noise ratio of the echo signal due to multipath propagation of the signal, various clutter, ambient noise and reverberation makes it difficult to identify underwater targets using active sonar. Attempts have been made to apply data-based methods such as machine learning or deep learning to improve the performance of underwater target recognition systems, but it is difficult to collect enough data for training due to the nature of sonar datasets. Methods based on mathematical modeling have been mainly used to compensate for insufficient active sonar data. However, methodologies based on mathematical modeling have limitations in accurately simulating complex underwater phenomena. Therefore, in this paper, we propose a sonar signal synthesis method based on a deep neural network. In order to apply the neural network model to the field of sonar signal synthesis, the proposed method appropriately corrects the attention-based encoder and decoder to the sonar signal, which is the main module of the Tacotron model mainly used in the field of speech synthesis. It is possible to synthesize a signal more similar to the actual signal by training the proposed model using the dataset collected by arranging a simulated target in an actual marine environment. In order to verify the performance of the proposed method, Perceptual evaluation of audio quality test was conducted and within score difference -2.3 was shown compared to actual signal in a total of four different environments. These results prove that the active sonar signal generated by the proposed method approximates the actual signal.