• Economic and Environmental Geology
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• v.56 no.3
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• pp.277-291
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• 2023

To analyze the crustal velocity structures beneath 21 broadband seismic stations in Gangwon Province, South Korea, we first applied the H-κ stacking method to 139 teleseismic event data (Mw ≥ 5.8 and the epicentral distance of 30° - 90°) occurring between March 18, 2019 and December 31, 2022 to estimate the Moho depths and V_p/V_s ratios beneath each station. The Moho depths and V_p/V_s ratios from the H-κ stacking method range from 24.9 to 33.2 km depth and 1.695 - 1.760, respectively, and the estimated V_p/V_s ratios were applied to the joint inversion of receiver functions and surface wave dispersion to obtain 1-D crustal velocity models beneath each station. The resulting Moho depths range from 25.9 to 33.7 km depth, similar to the results from the H-κ stacking method. Moho depth results from the both methods are generally consistent with Airy's isostasy. The 1-D crustal velocity models confirm that the existence of 2 km thick low-velocity layers with P-wave velocities of 5 km/s or less at some stations in the Taebaeksan basin, and at the stations CHNB and GAPB in northern Gangwon Province, which are located above the Cenozoic sedimentary layer. The station SH2B, although not overlying a sedimentary layer, has a low P-wave velocity near the surface, which is probably due to various factors such as weathering of the bedrock. We also observe a velocity inversion with decreasing velocity with depth at all stations within 4 - 12 km depths, and mid-crustal discontinuities possibly due to density differences in the rocks at around 10 km depth below some stations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.25-32
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• 2009

Currently, various types of TDM (Transportation Demand Management) policies are being studied and implemented in an attempt to overcome the limitations of supply oriented policies. In this context, this paper addressed issues of effectiveness and possible domestic implementation of the HOT lane. The possible site of implementation selected for this simulation study is part of the Kyung-bu freeway, where a dedicated bus lane is currently being operated. Minimum length of distance required in between interchanges and access points of the HOT lane for vehicles to safely enter and exit the lane, and traffic management policies for effectively managing the weaving traffic trying to enter and exit the HOT lane were presented. A 5.2km section of freeway from Ki-heuing IC to Suwon IC and a 8.3km section from Hak-uei JC to Pan-gyo JC have been selected as possible sites of implementation for the HOT lane, in which congestion occurs regularly due to the high level of travel demand. VISSIM simulation program has been used to analyze the effects of the HOT lane under the assumption that one-lane HOT lane has been put into operation in these sections and that the lane change rate were in between 5% to 30%. The results of each possible scenario have proven that overall travel speed on the general lanes have increased as well by 1.57~2.62km/h after the implementation of the HOT lane. It is meaningful that this study could serve as a basic reference data for possible follow-up studies on the HOT lane as one effective method of TDM policies. Considering that the bus travel rate would continue increase and assuming the improvement in travel speed on general lanes, similar case study can be implemented where gaps between buses on bus lane are available, as a possible alternative of efficient bus lane management policies.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.353-365
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• 2023

The effects of climate change on green infrastructure and environmental media remain uncertain and context-specific despite numerous climate projections globally. In this study, the extreme weather conditions in seven major cities in South Korea were characterized through statistical analysis of 20-year daily meteorological data extracted fro m the Korea Meteorological Administration (KMA). Additionally, the impacts of extreme weather on Nature-based Solutions (NbS) were determined through a comprehensive review. The results of the statistical analysis and comprehensive review revealed the studied cities are potentially vulnerable to varying extreme weather conditions, depending on geographic location, surface imperviousness, and local weather patterns. Temperature extremes were seen as potential threats to the resilience of NbS in Seoul, as both the highest maximum and lowest minimum temperatures were observed in the mentioned city. Moreover, extreme values for precipitation and maximum wind speed were observed in cities from the southern part of South Korea, particularly Busan, Ulsan, and Jeju. It was also found that extremely low temperatures induce the most impact on the resilience of NbS and environmental media. Extremely cold conditions were identified to reduce the pollutant removal efficiency of biochar, sand, gravel, and woodchip, as well as the nutrient uptake capabilities of constructed wetlands (CWs). In response to the negative impacts of extreme weather on the effectiveness of NbS, several adaptation strategies, such as the addition of shading and insulation systems, were also identified in this study. The results of this study are seen as beneficial to improving the resilience of NbS in South Korea and other locations with similar climate characteristics.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.641-649
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• 2023

This study compares and analyzes the performance of a shield manufactured using 3D printing technology to find out its applicability as a shield in high-energy electron beam therapy. Actual measurement and monte carlo simulations were performed to evaluate the shielding performance of 3D printing materials for high-energy electron beams. First, in order to secure reliability for the simulation, a source term evaluation was conducted by referring to the IAEA's TRS-398 recommendation. Second, to analyze the shielding performance of PLA+W (93%), a specimen was manufactured using a 3D printer, and the shielding rate by thickness according to electron beam energy was evaluated. Third, the shielding thickness required for electron beam treatment was calculated through a comparative analysis of shielding performance between PLA+W (93%) and existing shielding bodies. First, as a result of the evaluation of the source term through actual measurement and simulation, the TRS-398 recommendation was satisfied with an error of less than 1%, thereby securing the reliability of the simulation. Second, as a result of the shielding performance analysis for PLA+W (93%), 6 MeV electron beams showed a shielding rate of more than 95% at 3.12 mm, and 15 MeV electron beams showed a shielding rate of more than 90% at 10 mm thickness. Third, through simulations, comparative analysis between PLA+W (93%) materials and existing shields showed high shielding rates within the same thickness in the order of tungsten, lead, copper, PLA+W (93%), and aluminum. 6 MeV electron beams showed almost similar shielding rates at 5 mm or more and 15 MeV electron beams. Through this study in the future, it is judged that it can be used as basic data for the production and application of shielding bodies using PLA+W (93%) materials in high-energy electron beam treatment.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.767-773
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• 2023

To In this study, we sought to evaluate related factors affecting lung volume and their significance in pulmonary function and ventilation disorders. As experimental subjects, 206 normal adult men and women who underwent a low-dose chest CT scan and a spirometry test were selected at the same time. The experimental method was to measure lung volume using lung CT images obtained through a low-dose chest CT scan using deep learning-based AVIEW. Measurements were made using the LCS automatic diagnosis program. In addition, the results of measuring lung function were obtained using a spirometer, and gender and BMI were selected as related factors that affect lung volume, and significance was evaluated through an independent sample T-test with lung volume. As a result of the experiment, it was confirmed that in evaluating lung volume according to gender, all lung volumes of men were larger than all lung volumes of women. he result of an independent samples T-test using the respective average values for gender and lung volume showed that all lung volumes were larger in men than in women, which was significant (p<0.001). And in the evaluation of lung volume according to BMI index, it was confirmed that all lung volumes of adults with a BMI index of 24 or higher were larger than all lung volumes of adults with a BMI index of less than 24. However, the independent samples T-test using the respective average values for BMI index and lung volume did not show a significant result that all lung volumes were larger in BMI index 24 or higher than in BMI index less than 24 (p<0.055). In the evaluation of lung volume according to the presence or absence of pulmonary ventilation impairment, it was confirmed that all lung volumes of adults with normal pulmonary function ventilation were larger than all lung volumes of adults with pulmonary ventilation impairment. And as a result of the independent sample T-test using the respective average values for the presence or absence of pulmonary ventilation disorder and lung volume, the result was significant that all lung volumes were larger in adults with normal pulmonary function ventilation than in adults with pulmonary function ventilation disorder (p <0.001). Lung volume and spirometry test results are the most important indicators in evaluating lung health, and using these two indicators together to evaluate lung function is the most accurate evaluation method. Therefore, it is expected that this study will be used as basic data by presenting the average lung volume for adults with normal ventilation and adults with impaired lung function and ventilation in similar future studies on lung volume and vital capacity testing.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.373-380
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• 2023

This study surveyed and compared the temperature distribution in domestic refrigerators and freezers used in Korea to determine whether temperature varied according to the location of food storage. We selected 50 people to collect temperature data; among them, 25 measured the temperature of refrigerators, while the remaining measured the temperature of freezers. Consequently, the lowest and highest temperatures measured in domestic refrigerators were found to be -8.2℃ and 15.8℃, respectively, with an average temperature of 3.73℃. The temperature distribution based on internal location was: 5.06±1.69℃ for the door storage compartment, 4.18±1.19℃ for the inside wall surface, and 3.41±1.36℃ for the inner storage box. Significant temperature differences between the top and bottom were only identified at the door storage compartment (P<0.01). Further, the minimum and maximum temperatures measured in the freezer was -30.3℃ and 0.7℃, respectively, with an average temperature of -17.95℃. The temperature distribution based on location was: -17.19±1.68℃ for the door storage compartment, -17.81±1.07℃ for the inside wall surface, and -18.78±1.72℃ for the inside storage box. The results were similar to that of the refrigerator, with the lowest temperature in the inside storage box, and a significant temperature difference between the top and bottom noted only at the door (P<0.01). The maximum temperature difference (between locations) within the refrigerator and freezer was found to be 2.18 and 2.02℃, respectively. In conclusion, the temperature in the entire space was not constant; there were significant deviations at different storage locations. Therefore, public authorities should actively advise customers on the recommended storage locations for each food type. People will benefit from awareness about storage management, including avoiding storage of temperature-sensitive foods in door compartment.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.158-171
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• 2023

Pottery filled with organic materials was excavated from the G-2 building site of Yongjangseong Fortress, Jingo, a relic of the Goryeo Dynasty. In this study, the characteristics of organic material were confirmed by a scientific analysis of organic material in pottery found at the palace in Yongjangseong, Jindo. In addition, it was intended to review the analysis method to identify the natural resin and to secure characteristic components(biomarkers) for each natural resin and use them as basic data in the future. The organic materials in the pottery were analyzed using attenuated total reflectance Fourier-transformed infrared spectroscopy(ATR-FTIR) and gas chromatography mass spectrometry(GC-MS). The infrared spectral characteristics were estimated to be natural resin, and biomarkers of organic materials were identified as sesquiterpene-based compounds(C₁₅H₂₄, MW 204) and derivatives. The lacquer(T.vemicifluum) is composed mainly of alkenes, alkanes, and catechol. Pine resin(P.densiflora), on the other hand, is primarily composed of diterpenoid(abietic acid, pimaric acid) and Whangchil(yellow lacquer) is identified to have sesquiterpenes(such as selinene, muurolene, calamenene) as its main components. So, the organic material in the pottery can be identified as Whangchil by comparing their compounds with modern resin materials from Dendropanax. morbifera that correspond with the results. Whangchil, which is exuded from the Dendropanax. morbifera, has been used as a natural coating materials since ancient times, and it has been confirmed that the characteristic components are well preserved even 700 years later. It can be assumed that the interior Whangchil was stored not for use as a coating, but rather for ritual purposes when the building was constructed, because the pottery was found near the cornerstone. Furthermore, based on simplified sample preparation using pyrolysis-gas chromatography mass spectrometry(Py-GC-MS), the thermal decomposition products were found to be similar to the characteristic components, suggesting that this method can be applied to the identification of natural resins used in historic artifacts.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.1
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• pp.253-270
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• 2023

Research on investment determinants of accelerators, which are attracting attention by greatly improving the survival rate of startups by providing professional incubation and investment to startups at the same time, is gradually expanding. However, previous studies do not have a theoretical basis in developing investment determinants in the early stages, and they use factors of angel investors or venture capital, which are similar investors, and are still in the stage of analyzing importance and priority through empirical research. Therefore, this study verified for the first time in Korea the discrimination and effectiveness of investment determinants using accelerator investment determinants developed based on the business model innovation framework in previous studies. To this end, we first set the criteria for success and failure of startup investment based on scale-up theory and conducted a survey of 22 investment experts from 14 accelerators in Korea, and secured valid data on a total of 97 startups, including 52 successful scale-up startups and 45 failed scale-up startups, were obtained and an independent sample t-test was conducted to verify the mean difference between these two groups by accelerator investment determinants. As a result of the analysis, it was confirmed that the investment determinants of accelerators based on business model innovation framework have considerable discrimination in finding successful startups and making investment decisions. In addition, as a result of analyzing manufacturing-related startups and service-related startups considering the characteristics of innovation by industry, manufacturing-related startups differed in business model, strategy, and dynamic capability factors, while service-related startups differed in dynamic capabilities. This study has great academic implications in that it verified the practical effectiveness of accelerator investment determinants derived based on business model innovation framework for the first time in Korea, and it has high practical value in that it can make effective investments by providing theoretical grounds and detailed information for investment decisions.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.3
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• pp.51-76
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• 2022

Identifying the factors that influence the formation of the entrepreneurial intention is important in cultivating entrepreneurs and inducing entrepreneurial innovation in the country. Previous studies have mainly examined the direct effects of social cognition attributes as predictors on entrepreneurial intentions or entrepreneurial activities. However, the fundamental factors that these social cognition attributes are derived from have not been sufficiently addressed in the field of entrepreneurship. Based on social cognitive theory and schema theory, this study assumes that an individual's entrepreneurial experience is an important antecedent factor in forming social cognitive attributes, and reveals the mechanism for how experience forms entrepreneurial intention. To this end, this study analyzes the influence of entrepreneurs' prior experience of entrepreneurial activities on entrepreneurial self-efficacy, opportunity recognition, and fear of failure which are considered to be the main variables that shape entrepreneurial intention. And it analyzes how these factors have a significant effect on entrepreneurship intention. Along with this, the mediating role of these social cognitive attributes is analyzed in order to understand the path that leads from entrepreneurial experience to entrepreneurial intention. This study also suggests how gender moderates the effect of entrepreneurship experience on social cognitive attributes. As a result of the analysis, it was found that entrepreneurial experience increase entrepreneurial self-efficacy and opportunity recognition of entrepreneurs, and decrease the fear of failure. These social perception attribute significantly mediate the relationship between entrepreneurial experience and entrepreneurial intention. This study also found that there are significant moderating effects of gender on the relationship of entrepreneurial experience and both of entrepreneurial self-efficacy and fear of failure. This study also analyzed the impact of the entrepreneurial experience of failure, which corresponds to the detailed experience. Similar to the results of entrepreneurial experience analysis, entrepreneurial experience of failure plays a role in enhancing entrepreneurial self-efficacy. However, its effect on opportunity recognition and fear of failure were not significant. An empirical analysis of data related to 25,047 entrepreneurs from 87 countries, using the Global Entrepreneurship Monitor (GEM), shows the differences in the formation of individuals' entrepreneurial intentions according to entrepreneurial experience and the mediating role of social cognitive attributes. The study has embodied the social cognitive theory on entrepreneurial intention by shedding light on the variables that are important but alienated for increasing entrepreneurial intention. Moreover, the study enhances the understanding of cognitive processes leading from individual experiences to entrepreneurial intentions. This study also emphasizes the importance of differentiated approach by gender for boosting entrepreneurial intention through analysis of moderating effect of gender.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.263-269
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• 2023

This study aims to contribute to the research on resource recovery for the rapidly declining population of Liparis tanakae by observing the larval development process and the morphology of juveniles based on their growth. Natural spawning eggs collected in Yeosu were used for observing the process of egg development and larval morphology. The water temperature during the rearing process was maintained at 12.3~13.5℃ (average 12.7℃). The fertilized eggs had an egg diameter ranging from 1.57 to 1.79 mm (average 1.71 mm) and were spherical and adhesive. Within 4 hours 35 minutes after fertilization, they reached the two-cell stage, and after 74 hours 10 minutes, the formation of the yolk sac began. At 106 hours post-fertilization, a caudal fin appeared at the tail tip. Hatching began at 526 hours, and the larvae developed with the yolk sac positioned just behind the eyes. The newly hatched larvae had both the mouth and anus open. Melanophores appeared inside the lower jaw and around the tail on the third day after hatching. By the 16th day after hatching, most of the yolk was absorbed, and melanophores were visible in the head region. Finally, on the 63rd day after hatching, the head region significantly developed, and the body shape and mouth were similar to those of an adult fish, signifying the transition to the juvenile stage. This study will serve as valuable data for aquaculture techniques related to the conservation and restoration of fish species based on the hatching and juvenile morphology of Liparis tanakae.