• Food Science and Preservation
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• v.16 no.4
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• pp.472-481
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• 2009

Response surface methodology (RSM) is frequently used for optimization studies. In the present work, RSM was used to determine the antimicrobial activitiesof grapefruit seed extract (GFSE) and a lactic acid mixture (LA) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Pseudomonas fluorescens, and Vibrio parahaemolyticus. A central composite design was used to investigate the effects of independent variables on dependent parameters. One set of antimicrobial preparations included mixtures of 1% (w/w) GFSE and 10% (w/w) LA, in which the relative proportions of component antimicrobials varied between 0 and 100%. In further experiments, the relative proportions were between 20% and 100%. Antimicrobial effects against various microorganisms were mathematically encoded for analysis. The codes are given in parentheses after the bacterial names, and were S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$). The optimum antimicrobial activity of the 1% (w/w) GFSE:10% (w/w) LA mixture against each microorganism was obtained by superimposing contour plots ofantimicrobial activities on measures of response obtained under various conditions. The optimum rangesfor maximum antimicrobial activity of a mixture with a ratio of 1:10 (by weight) GFSE and LA were 35.73:64.27 and 56.58:43.42 (v/v), and the optimum mixture ratio was 51.70-100%. Under the tested conditions (a ratio of 1% [w/w] GFSE to 10% [w/w] LA of 40:60, and a concentration of 1% [w/w] GFSE and 10% [w/w] LA, 70% of the highest value tested), and within optimum antimicrobial activity ranges, the antimicrobial activities of the 1% (w/w) GFSE:10% (w/w) LA mixture against S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$) were 24.55, 25.22, 20.20, 22.49, 23.89, and 28.04 mm, respectively. The predicted values at optimum conditions were similar to experimental values.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.329-333
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• 2006

Most of volcanic ash soils in South Korea are distributed in Jeju province which is an island placed on southern part of Korea and has steep slope mountain area. There are many soils containing high contents of organic matter (OM) derived from volcanic ash in Jejudo, also. Therefore, irrigation and drainage in volcanic ash soil different with general soil which has low OM content have to be applied with another management way, but studies searching appropriate methods for them are set on insufficient situation because the area of volcanic ash soil in South Korea is only 1.3% (130,000ha). This study was conducted for analysis of soil water content and irrigation quantity appropriate for crops cultivated in volcanic ash soil with high OM content. Although soils with different soil color have the same soil texture, soil water characteristics curve by soil color showed the difference of water retention capability by OM content. But, this characteristics classified with soil color could be unified by scaling technique with similitude analysis method which get dimensionless water content using a present water content, a residual water content and saturated water content (or water content at 10kPa). A relation of gravimetric soil water content (GSWC) and dimensionless water content by the results showed a form of power function. The dimensionless water content (DWC) express a relative saturation degree of present water content. This was also expressed by van Genuchten model which describe the relation between relative saturation degrees and matric potentials. These results on soil water characteristics curve (SWCC) of volcanic ash soil will be the basic of irrigation plan in area having high organic contents into soil.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.3
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• pp.97-110
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• 2019

This study analyzed various factors of influence affecting the will to start a business and established and empirically analyzed a research model to see which factors significantly affect the will to start a business. To this end, we investigated the general characteristics and experiences of individuals, conducted a study on the will to start a business, and analyzed the entrepreneurship passion for startups, the ability to find business opportunities, and the ability to connect with partner companies. The intent to start a business survey was investigated in a recertive style with a 7 point scale, and the reliability and feasibility review were analyzed through the PLS analysis method, which enables the implementation of a measurement model and a structural model. To collect valid data, the survey was conducted using an entrepreneurial curriculum class hours to collect and analyze 421 data. In summary, the results are as follows: First, college students have many opportunities to develop their capabilities through competitions held by universities and support institutions, and by utilizing them, they have no fear of starting a business. Second, the ability of students to discover product clients themselves has been improved by fostering entrepreneurship in the special lectures on startup in universities. Third, it can be seen that it has received various information on startups from support agencies to enhance its commitment to startups. The implications are as follows. First, they should foster entrepreneurship among college students by offering practical oriented courses that can broaden their understanding of startups. Second, it needs to be improved from entrepreneurial enthusiasm to a program that can grow into a company that can collaborate with partner companies and confirm its commitment to corporate establishment and product development and determine market opportunities. Third, it is necessary to establish an ecosystem of start-ups that can carry out systematic planning and performance management as it is weak to carry out projects with will to startups.

• Korean Journal of Child Education & Care
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• v.18 no.4
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• pp.1-25
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• 2018

Purpose: The purpose of this study was to explore about 2-year-old infants' attachment security to a child care teacher and peer play process through a case study. For this purpose, the attachment security was assessed with attachment Q-set to 2-year-old five infants at a day care center in Seoul. Participants of this study are four infants included two infants attached securely to their child care teacher and two infants attached insecurely to their child care teacher. Methods: Participant observation was conducted from April 12 to July 19 in 2018 through 36 observations in free play activities. The Data collected from the transcriptions of video shoots and teachers' interviews, child care plans, and reflexive journal was analyzed and interpreted. Results: The main results of the research were as follows: The beginning of peer play, when infants invited their peers to play, secure attachment infants selected suitable play partners and asked for a specific play behaviors. However, insecure attachment infants invited unsuitable play partners and asked uncertainly play actions to peers. In addition, when infants entered in-progress play, secure attachment infants understood the context of play but insecure attachment infants did not understand the context of play. In the progress of peer play, secure attachment infants cooperated with peers, shared play objects, but insecure attachment infants did not cooperate complementally with peers and express only their opinions. As well, insecure attachment infants could not play harmoniously without child care teacher's interventions. In the end of the peer play, secure attachment infants finished in collaboration with peers but insecure attachment infants failed to finish with the peers and was turned into play with the child care teacher because of peer conflict. Conclusion/Implications: This study has implications for basic resources to think about the role of child care teachers by helping them understand about the relation 2-year-old infants' attachment security to them and peer play process.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.230-238
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• 2018

Purpose: Metacarpal fractures are common injuries of the hand. They are treated using closed reduction (CR) or open reduction (OR) techniques. The management strategy depends on fracture site characteristic and fixation methods. In this study, we evaluated pre- and postoperative fracture angulation, when metacarpal fractures bad been treated using two different techniques: CR with parallel transverse pinning and OR with plate fixation. Methods: Forty-six patients undergoing anatomic reduction to treat extra-articular metacarpal fractures were recruited. They were included in one of two therapeutic groups: Group 1, CR with parallel transverse pinning (n=21); Group 2, OR with plate fixation (n=25). Fracture angulation values have been measured on pre- and postoperative radiologic images. Values were compared between pre- and postoperative states, and between corresponding measurements of each group. Results: All extra-articular metacarpal fractures were successfully treated without wound related complications or the limit of joint motion. Both groups demonstrated adequate reduction at immediate postoperative period (postoperative angulation of group 1, $20^{\circ}{\pm}7^{\circ}$; group 2, $19^{\circ}{\pm}5^{\circ}$). During the observation at follow-up period, Group 1 exhibited slight recurrence (follow-up angulation of group 1, $24^{\circ}{\pm}10^{\circ}$). Nonetheless, Group 2 showed adequate reduction state in both immediate postoperative and long-term follow-up periods (follow-up angulation of group 2, $18^{\circ}{\pm}6^{\circ}$). Conclusion: Extra-articular metacarpal fractures were successfully restored without functional complications. CR with parallel transverse pinning method exhibited recurrence after pin removal, which necessitates cautious postoperative exercise and monitoring.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.558-568
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• 2021

Poor supervision and tourism activities have resulted in forest degradation in islands in Korea. Since the southern coastal region of the Korean peninsula was originally dominated by warm-temperate evergreen broad-leaved forests, it is desirable to restore forests in this region to their original vegetation. In this study, we identified suitable areas to be restored as evergreen broad-leaved forests by analyzing the environmental factors of existing evergreen broad-leaved forests in the islands of Jeollanam-do. We classified forest lands in the study area into six vegetation types from Sentinel-2 satellite images using a deep learning algorithm and analyzed the tolerance ranges of existing evergreen broad-leaved forests by measuring the locational, topographic, and climatic attributes of the classified vegetation types. Results showed that evergreen broad-leaved forests were distributed more in areas with a high altitudes and steep slope, where human intervention was relatively low. The human intervention has led to a higher distribution of evergreen broad-leaved forests in areas with lower annual average temperature, which was an unexpected but understandable result because an area with higher altitude has a lower temperature. Of the environmental factors, latitude and average temperature in the coldest month (January) were relatively less contaminated by the effects of human intervention, thus enabling the identification of suitable restoration areas of the evergreen broad-leaved forests. The tolerance range analysis of evergreen broad-leaved forests showed that they mainly grew in areas south of the latitude of 34.7° and a monthly average temperature of 1.7℃ or higher in the coldest month. Therefore, we predicted the areas meeting these criteria to be suitable for restoring evergreen broad-leaved forests. The suitable areas cover 614.5 km², which occupies 59.0% of the total forest lands on the islands of Jeollanamdo, and 73% of actual forests that exclude agricultural and other non-restorable forest lands. The findings of this study can help forest managers prepare a restoration plan and budget for island forests.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.71-78
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• 2021

Green areas and the area of available horizontal surfaces are gradually decreasing due to the overcrowding of buildings. It is adversely affecting the urban climate and ecosystem. However, the recognition of the importance of green areas is gradually increasing. As a result, the importance of wall greening using vertical surfaces is growing. However, despite the fact that domestic wall greening guidelines and institutions related to orientations restrict planting. there was no study to determine whether there were actual differences in plant growth due to orientations. Therefore, this study compared and analyzed the plant growth characteristics by orientations to apply actual wall greening to cities. The experiment was conducted from May to September 2020. First of all, three octave walls were constructed to measure the temperature, the illumination, and the length of the plants once a week. The plants included Parthenocissus tricuspidata, Hedera rhombea, and Euonymus radicans cv. Aueonmarinata Rehd plants. As a result of the study, Parthenocissus tricuspidata was prolific in the north, and Hedera rhombea, and Euonymus radicans cv. Aueonmarinata Rehd plants were prolific in the south. All three types of plants were prolific in June-July, and the Parthenocissus tricuspidata was prolific in grass-growing, and in August, all the walls were 100% covered. Hedera rhombea had the lowest rate of herbaceous growth, and the vertical coverate was also lower at an average of 45%, but among the three plants, the sheath of the horizontal surface coverate was the highest. Euonymus radicans cv. Aueonmarinata Rehd was low in the speed of herbaceous growth, and finally, the walls were 100% covered except for the north and northwest directions. It was found that not all plants used for wall greening show the same growth, and the difference in growth varies more depending on plants than the effect of orientations. Therefore, it is better to identify the characteristics of plant growth and plant suitable plants for each directions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.263-276
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• 2021

Marine benthic organisms have been used as the indicators for the environment assessment and recently considered as a very important component in the biodiversity and ecosystem restoration. In Korean waters, the quantitative data on marine benthos was used as one of major components for the marine pollution assessment for 50 years since 1970s. The species identification which is an important factor for the quantitative biological data was mainly performed by the marine benthic ecologists. This leads to the deterioration of the data quality on marine benthos from the misidentication of major taxonomic groups due to the lack of taxonomic expertise in Korea. This taxonomic problem has not been solved until now and remains in most data from national research projects on the marine ecosystems in Korean waters. Here we introduce the quality assurance and control (QA/QC) system for the marine biological data in UK, that is, NMBAQC (Northeast Atlantic Marine Biological Analytic and Quality Control) Scheme which has been performed by private companies to solve similar species identification problems in UK. This scheme asks for all marine laboratories which want to participate to any national monitoring programs in UK to keep their identification potency at high level by the internal quality assurance systems and provides a series of taxonomic workshops and literature to increase their capability. They also performs the external quality control for the marine laboratories by performing the Ring Test using standard specimens on various faunal groups. In the case of Korea, there are few taxonomic expertise in two existing national institutions and so they can't solve the taxonomic problems in marine benthic fauna data. We would like to provide a few necessary suggestions to solve the taxonomic problems in Korean marine biological data in short-terms and long-terms: (1) the identification of all dominant species in marine biological data should be confirmed by taxonomic expertise, (2) all the national research programs should include taxonomic experts, and (3) establishing a private company, like the Korea marine organism identification association (KMOIA), which can perform the QA/QC system on the marine organisms and support all Korean marine laboratories by providing taxonomic literature and species identification workshops to enhance their potency. The last suggestion needs more efforts and time for the establishment of that taxonomic company by gathering the detailed contents and related opinions from diverse stakeholders in Korea.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.120-132
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• 2022

Recently, the rapid increase in vacant houses in urban areas has caused various problems such as worsening urban landscape, causing safety accidents, crime accidents, and hygiene problems. According to the Statistics Korea Future Population Estimation results, the growth rate of Korean population and households is expected to continue to decrease, which is likely to lead to an increase in the occurrence of vacant houses. If the problem caused by the occurrence of vacant houses is neglected, it causes not only a physical decline such as a deterioration of the residential environment but also a social and economic decline. In order to solve this problem, it is necessary to grasp the spatial distribution characteristics of vacant houses at the local level considering the existence of regional characteristics and spatial influence. Therefore, in this study, in order to measure global spatial autocorrelation, the analysis was conducted centering on the old downtown area of Busan, where there are many vacant houses through Moran's I and Geographically Weighted Regression(GWR). In addition, the distribution of vacant houses in different spatial units in Eup_Myeon_Dong and Census was analyzed to evaluate the possibility of Modifiable Areal Unit Problem(MAUP), which differ in the results of spatial analysis as the spatial analysis units change. As a result of the analysis, the occurrence of vacant houses by Eup_Myeon_Dong in the old downtown area of Busan had spatial heterogeneity, and the spatial analysis results of vacant houses were different as the spatial analysis units were different. Accordingly, in order to understand the exact distribution characteristics of vacant house occurrence, spatial dimensions using the GWR model should be considered, and it is suggested that consideration of the MAUP is necessary.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.433-440
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• 2023

High dose rate brachytherapy is a cancer treatment that intensively irradiates radiation to tumors by inserting isotopes with high dose rates into the body. For such a treatment, it is necessary to deliver an accurate dose to the tumor tissue through an accurate treatment plan while delivering only a minimum dose to the normal tissue. Therefore, it is very important to check the location accuracy of the source through accurate Quality Assurance (QA) in clinical practice. However, since the source position is determined using a ruler, automatic radiographer, video monitor, etc. in clinical practice, it yields inaccurate results. In this study, a semiconductor dosimeter using CsPbI₂Br and CsPbIBr₂ was fabricated. And, in order to analyze whether it is more suitable for the relative QA dosimeter for brachytherapy device among the two materials, the radiation detection ability of each was compared and evaluated. In order to evaluate the radiation detection ability in brachytherapy, the reproducibility and linearity of the two materials were evaluated in ¹⁹²IR. In the reproducibility evaluation, CsPbI₂Br presented a Relative Standard Deviatio(RSD) of 0.98% and CsPbIBr₂ presented an RSD of 3.45%. In the linearity evaluation, the coefficient of determination (R²) of CsPbI₂Br was presented as 0.9998, and the R² of CsPbIBr₂ was presented as 0.9994. As a result of the evaluation, it was found that CsPbI₂Br was more stable in radiation detection while satisfying the evaluation criteria in the dosimeter manufactured in this experiment. Therefore, CsPbI₂Br material is suitable for application as a relative dosimeter for radiation detection in brachytherapy devices.