• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.147-156
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• 2006

This study was initiated to evaluate the growth characteristics of seven creeping bentgrass cultivars in summer, 'Penncross' showed the worst visual quality, whereas 'Penn A-4' and 'Crenshaw' the best quality. 'Putter', which was maintained a fair quality during the test period, was regarded as a good cultivar because of no significant variation in summer as compared to the other caltivars. 'Crenshaw',' L-93' and 'Penn A-4' were greater in chlorophyll content and 'Penncross' lowest during the summer. Also, 'SR1020' had a low content of chlorophyll. 'Putter' greatly increased in chlorophyll content after fertilization. The highest shoot density($19.3/cm^2$) was found with 'L-93' in early August, followed by 'Crenshaw', 'Penn A-4', 'Putter', 'Dominant', and 'SR1020' in that order. However, 'Penncross' was lowest($15.7/cm^2$). As for a root length, 'L-93' was longest, being over an average 5.5cm. 'Penn A-4' and 'Putter' also showed good result in root growth. However, the root length considerably decreased with 'SR1020', 'Penncross' and 'Dominant' in summer. Brown patch was a serious disease for the most cultivars, except 'Penncross'. 'Dominant' had the most serious damage. 'Putter', 'L-93', 'Crenshaw', 'SR1020', and 'Penn A-4' were also greater in damage over the others. In regards of algae occurrence in summer, 'Penn A-4' had the least damage, while 'Dominant' the greatest. In conclusion, 'Crenshaw', 'Penn A-4' and 'L-93' were the best cultivars in terms of summer growth. Conversely, 'Penncross' was the poorest one. However, this study was conducted under the conditions of one-year old green. Accordingly, in-depth experiment should be done over several years to elucidate the characteristics of growth for the wide range of creeping bentgrass cultivars during the summer.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.7-17
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• 2005

The determination of seismic velocities in refractors for near-surface seismic refraction investigations is an ill-posed problem. Small variations in the computed time parameters can result in quite large lateral variations in the derived velocities, which are often artefacts of the inversion algorithms. Such artefacts are usually not recognized or corrected with forward modelling. Therefore, if detailed refractor models are sought with model based inversion, then detailed starting models are required. The usual source of artefacts in seismic velocities is irregular refractors. Under most circumstances, the variable migration of the generalized reciprocal method (GRM) is able to accommodate irregular interfaces and generate detailed starting models of the refractor. However, where the very-near-surface environment of the Earth is also irregular, the efficacy of the GRM is reduced, and weathering corrections can be necessary. Standard methods for correcting for surface irregularities are usually not practical where the very-near-surface irregularities are of limited lateral extent. In such circumstances, the GRM smoothing statics method (SSM) is a simple and robust approach, which can facilitate more-accurate estimates of refractor velocities. The GRM SSM generates a smoothing 'statics' correction by subtracting an average of the time-depths computed with a range of XY values from the time-depths computed with a zero XY value (where the XY value is the separation between the receivers used to compute the time-depth). The time-depths to the deeper target refractors do not vary greatly with varying XY values, and therefore an average is much the same as the optimum value. However, the time-depths for the very-near-surface irregularities migrate laterally with increasing XY values and they are substantially reduced with the averaging process. As a result, the time-depth profile averaged over a range of XY values is effectively corrected for the near-surface irregularities. In addition, the time-depths computed with a Bero XY value are the sum of both the near-surface effects and the time-depths to the target refractor. Therefore, their subtraction generates an approximate 'statics' correction, which in turn, is subtracted from the traveltimes The GRM SSM is essentially a smoothing procedure, rather than a deterministic weathering correction approach, and it is most effective with near-surface irregularities of quite limited lateral extent. Model and case studies demonstrate that the GRM SSM substantially improves the reliability in determining detailed seismic velocities in irregular refractors.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1306-1313
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• 2011

A liquid fertilizer treated with slurry composting and biofiltration (SCB) process has been applied increasingly on agricultural field but the effects on the soil properties and crop production has not been throughly evaluated. This study was conducted to investigate the effect of the SCB application on soil chemical properties and the growth of radish and corn. SCB liquid fertilizer as a basal fertilization was treated with five levels based on $6kg\;10a^{-1}$ for radish and $10kg\;10a^{-1}$ for corn. The experimental design was the completely randomized block design with five levels and three replicates. Electrical conductivity (EC), $NO_3$-N, Exch. K and Exch. Na increased depending on the treatment levels of SCB. There were no changes in soil organic matter, Avail. $P_2O_5$, Exch. Ca and Exch. Mg. EC, $NO_3$-N and Exch. Na content decreased as precipitation increased. Especially, they decreased up to the initial condition before the treatment after the heavy rainy season in 2008. Although Exch. K decreased at the rainy season, they remained relatively higher content after the experiment on August, 2008. Fresh weight and the amount of N uptake of radish increased due to the levels of SCB, but corn did not present any significant increase. It is recommended that we need to decide the proper amount of SCB as well as the application method on the field to increase the productivity and decrease environmental stress. Additional experiments also need to clarify the effect of the trace element and heavy metal accumulations due to long term application of SCB.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.85-99
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• 2021

Due to the continuous unemployment problem, the number of jobs is gradually decreasing, and entrepreneurship is emerging as an alternative. This is because, despite the government operating various start-up support programs to build a start-up-friendly culture, young entrepreneurs cannot endure the valley of death and disappear. Therefore, through this study, we intend to provide implications by analyzing the impact on Entrepreneurial satisfaction, which is essential for continuously running a business, and life satisfaction, which can act as a social awareness. This study was conducted with 573 non-wage workers who belonged to the founders among the participants of the 'College Graduation Occupational Migration Path Survey(GOMS)' survey provided by the Korea Employment Information Service. In order to analyze the relationship between entrepreneurial competency and job fit, Entrepreneurial satisfaction, and life satisfaction, the analysis was conducted using the SPSS 23.0 program. The main research results are summarized as follows. First, entrepreneurial competency has a positive effect on Entrepreneurial satisfaction and life satisfaction. Second, job fit indicates a moderating role in the relationship between entrepreneurial competency and Entrepreneurial satisfaction. Third, start-up satisfaction appears to have a partial mediating role in the relationship between entrepreneurial competency and life satisfaction. Fourth, as a result of analyzing the difference between groups according to the type of start-up(single/partnership), the group that worked together showed higher Entrepreneurial satisfaction and life satisfaction. The main implications of this study are: First, in order to increase the Entrepreneurial satisfaction and life satisfaction of university graduates who are the subject of the study, it will be necessary to design a program that can diagnose and enhance the entrepreneurial competency of students at the university level. Second, entrepreneurial competency is a basic intrinsic factor that founders must have, and it should act as an important evaluation factor when selecting founders for support programs from start-up support organizations as well as founders. Third, it is necessary to maintain mutual trust by documenting problems (positions, wages, management rights, distribution of profits, etc.) that may occur in joint ventures with objective data. Fourth, it is necessary to establish an environment in which the MZ generation, armed with the challenging spirit and creativity, can continue to take on challenges even if they fail.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.548-556
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• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.79-96
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• 2021

Green infrastructure planning represents landscape planning measures to reduce particulate matter. This study aimed to derive factors that may be used in planning green infrastructure for particulate matter reduction using text mining techniques. A range of analyses were carried out by focusing on keywords such as 'particulate matter reduction plan' and 'green infrastructure planning elements'. The analyses included Term Frequency-Inverse Document Frequency (TF-IDF) analysis, centrality analysis, related word analysis, and topic modeling analysis. These analyses were carried out via text mining by collecting information on previous related research, policy reports, and laws. Initially, TF-IDF analysis results were used to classify major keywords relating to particulate matter and green infrastructure into three groups: (1) environmental issues (e.g., particulate matter, environment, carbon, and atmosphere), target spaces (e.g., urban, park, and local green space), and application methods (e.g., analysis, planning, evaluation, development, ecological aspect, policy management, technology, and resilience). Second, the centrality analysis results were found to be similar to those of TF-IDF; it was confirmed that the central connectors to the major keywords were 'Green New Deal' and 'Vacant land'. The results from the analysis of related words verified that planning green infrastructure for particulate matter reduction required planning forests and ventilation corridors. Additionally, moisture must be considered for microclimate control. It was also confirmed that utilizing vacant space, establishing mixed forests, introducing particulate matter reduction technology, and understanding the system may be important for the effective planning of green infrastructure. Topic analysis was used to classify the planning elements of green infrastructure based on ecological, technological, and social functions. The planning elements of ecological function were classified into morphological (e.g., urban forest, green space, wall greening) and functional aspects (e.g., climate control, carbon storage and absorption, provision of habitats, and biodiversity for wildlife). The planning elements of technical function were classified into various themes, including the disaster prevention functions of green infrastructure, buffer effects, stormwater management, water purification, and energy reduction. The planning elements of the social function were classified into themes such as community function, improving the health of users, and scenery improvement. These results suggest that green infrastructure planning for particulate matter reduction requires approaches related to key concepts, such as resilience and sustainability. In particular, there is a need to apply green infrastructure planning elements in order to reduce exposure to particulate matter.

• Journal of Korea Water Resources Association
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• v.54 no.7
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• pp.535-544
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• 2021

Agricultural water occupies 48% of water demand, and management of agricultural reservoirs is essential for water resources management within agricultural basins. For more efficient use of agricultural water, monitoring the distribution of water resources in agricultural reservoirs and agricultural basins is required. Therefore, in this study, three threshold determination methods (i.e., fixed threshold, Otsu threshold, Kittler-Illingworth (KI) threshold) were compared to detect terrestrial water bodies using Sentinel-1 images for 3 years from 2018 to 2020. The purpose of this study was to evaluate methods for determining threshold values to more accurately estimate the reservoir area. In addition, by analyzing the relationship between the water surface and water storage at the Edong, Gosam, and Giheung reservoirs, water storage based on the SAR image was estimated and validated with observations. The thresholding method for detecting a waterbody was found to be the most accurate in the case of the KI threshold, and the water storage estimated by the KI threshold indicated a very high agreement (r = 0.9235, KGE' = 0.8691). Although the seasonal error characteristics were not observed, the problem of underestimation at high water levels may occur; the relationship between the water surface and the water storage could change rapidly. Therefore, it is necessary to understand the relationship between the water surface area and water storage through ground observation data for a more accurate estimation of water storage. If the use of SAR data through water resources satellites becomes possible in the future, based on the results of this study, it is judged that it will be beneficial for monitoring water storage and managing drought.

• Journal of the Korean earth science society
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• v.42 no.3
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• pp.311-324
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• 2021

Recently, ten geosites have been considered in Hwaseong for endorsement as national geoparks, including the Jebudo, Gojeongri Dinosaur Egg Fossils, and Ueumdo geosites. The Jebudo geosite in the southern part of the Seoul metropolitan area has great potential for development as a new geoscience educational site because it has geological, geographical (landscape), and ecological significance. In this study, we described the geological characteristics through field surveys in the Jebudo geosite. We evaluated its potential as a geo-education site based on comparative analysis with other geosites in Hwaseong Geopark. In addition, we reviewed the practical effect of field education at geosites on the essential concepts and critical competence-oriented education emphasized in the current 2015 revised science curriculum. The Jebudo Geosite is geologically diverse, with various metamorphic rocks belonging to the Precambrian Seosan Group, such as quartzite, schist, and phyllite. Various geological structures, such as clastic dikes, faults, joints, foliation, and schistosity have also been recorded. Moreover, coastal geological features have been observed, including depositional landforms (gravel and sand beaches, dunes, and mudflats), sedimentary structures (ripples), erosional landforms (sea cliffs, sea caves, and sea stacks), and sea parting. The Jebudo geosite has considerable value as a new geo-education site with geological and geomorphological distinction from the Gojeongri Dinosaur Egg Fossils and Ueumdo geosites. The Jebudo geosite also has opportunities for geo-education and geo-tourism, such as mudflat experiences and infrastructures, such as coastal trails and viewing points. This geosite can help develop diverse geo-education programs that improve key competencies in the science curriculum, such as critical thinking, inquiry, and problem-solving. Furthermore, by conducting optimized geo-education focused on the characteristics of each geosite, the following can be established: (1) the expansion of learning space from school to geopark, (2) the improvement of understanding of specific content elements and linkage between essential concepts, and (3) the extension of the education scope throughout the earth system. There will be positive impacts on communication, participation, and lifelong learning skills through geopark education.

• 한국사회정책
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• v.25 no.2
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• pp.125-163
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• 2018

Social and health problems related to drinking are serious. Drinking behavior is affected not only by personal factors but also by environment factors. The purpose of this study is to find out how the alcoholic beverage stores in community influence the drinking behaviors of individuals after adjusting the individual level variables and provide it as basic data for alcohol related regulatory policies. In order to identify the factors affecting drinking behavior, we conducted a multilevel logistic regression analysis with high-risk drinking and current drinking as dependent variables. Individual-level data provided by 2015 community health survey from respondents of urban residents, and regional level data provided by the National Statistical office. The variables such as age, education level, and income level were used as individual level variables and the number of basic living allowances, divorce rate, and the number of pubs were used as community level variables. According to the research results, after controlling all variables, the number of bar, retail per $1km^2$ in residential area effect on current drinking. But, they are not effect on high risk drinking. In the high risk drinking, only the divorce rate effect on drinking behavior. As a result of the stratified analysis, there was no difference in the current drinking. But, it shows that the higher the number of retail stores and the total alcohol availability, the higher risk drinking behavior in the 60s. The results of this study suggest that policies aimed not only on individuals but also on the local environment are necessary.

• Journal of Korean Philosophical Society
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• v.131
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• pp.199-222
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• 2014

This essay aims at clarifying Dasan Jeong Yagyong's view on Jingfang's yaobian theory. As is well known, Jingfang was a scholar of the Earlier Han period who exerted a profound influence on the theoretical development of Xiangshu School by creating the various techniques for interpreting the Zhouyi. Jingfang is also important in relation with Dasan's commentary of the Zhouyi, because some part of Dasan's interpreting techniques are thought to have their origin in Jinfang. For example, Dasan used the bigua theory of which the origin could be traced back into Jingfang. However, in this article, I did not deal with the bigua theory because I am going to write another article about it. In stead, my focus will be put on analyzing how Dasan evaluated Jingfang's yaobian theory. The main issues of my argument can be summarized as following. Firstly, in terms of yaobian, Jeong Yagyong called attention to Jingfang's annotation on the Zhouyi in which Jingfang utilized the yaobian method in three occasions, i.e., the first nine of the Qian(乾初九), the sixth nine of the Guan(觀上九), and the sixth nine of the Bo(剝上九). It seems that Jeong Yagyong set forth enough evidence about Jingfang's use of yaobian at least in relation to two cases of the first nine of the Qian and the sixth nine of the Bo, while the other evidence of the sixth nine of the Guan was not so persuasive. However, even if it is evident that Jingfang made use of the yaobain in two cases, there is no reason to equate it with that of Dasan. If one takes a close look, it becomes clear that Jingfang's way of yaobain is very different from Dasan's. Secondly, Jeong Yagyong mentioned Jiayi(賈誼) who lived about one hundred years before Jingfang, as the person who utilized the yaobian in his book of Xinshu(新書). If it is certain that Jiayi was aware of the yaobian, we can assume that the yaobian technique had been handed down from Jiayi to Jingfang. The manuscript excavated from the Mawangdui tomb also increases the possibility that Jiayi could have had the knowledge on the yaobian. In the chapter of Muhe(繆和) of the Mawangdui Zhouyi, there appears the phrase, i.e., "the first six of the qian, qian goes to mingyi," which shows exactly the same form of the yaobian in the Mr Zuo's Spring and Autumn Annals(春秋左氏傳). The burial period of Mawangdui tomb is estimated at the same year of B.C.168 in which Jiayi died. Therefore, judging from that fact, it becomes evident that the yaobain method was widely diffused around B.C.168. Subsequently, it is possible to infer that the yaobian method had been handed down from the period of Jiayi to Jingfang. If we could present the persuasive evidence to support that inference, it would also have the effect of consolidating Dasan's argument about the yaobian.