• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.33-42
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• 2010

The main objective of this study was to offer informations about the current conditions of stream sediments and to evaluate biochemical methane potentials of stream sediments from the urban streams in Busan city using conventional BMP tests. First we select total 5 urban streams and collect sediment samples. Then, COD, proximate analysis, volatile solid, organic carbon content and elemental analysis were conducted to determine characteristics of the sediments. Results show that COD, volatile solid and organic carbon content are determined in the range of $15.20{\sim}75.07mg\;g^{-1}$, 2.34~11.54% and 1.28~34.21%, respectively. Also, several biochemical methane potential tests were performed in a laboratory. As a result, pH values of the reactors generally increased and then stabilized at 7.11~7.35. In addition, C/N ratio, ultimate methane and carbon dioxide yield (mL/g VS) and biodegradability (%) were determined to 1.05~10.27, 10.1~179.4, 10.3~34.4 and 4.0~30.1, respectively. For the determination of the correlations between ultimate methane yield and ultimate carbon dioxide yield, C/N ratio, COD, volatile solid and organic carbon content, a linear model was fitted to the data using a least-squares algorithm. As a result, except for COD ($r^2=0.7586$) and volatile solid ($r^2=0.7876$), Linear model was well fitted to each data with good values of the correlation coefficient ($r^2=0.9795{\sim}0.9858$). Finally, we propose empirical equations, which contain C/N ratio or TOC, for the prediction of ultimate methane yield for the urban streams in Busan city.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.687-701
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• 2014

Sea ice is generally accepted as an important factor to understand the process of earth climate changes and is the basis of earth system models for analysis and prediction of the climate changes. To continuously monitor sea ice changes at kilometer scale, it is demanded to create more accurate grid data from the current, limited sea ice data. In this paper we described a downscaling method for Advanced Microwave Scanning Radiometer 2 (AMSR2) Sea Ice Concentration (SIC) from 10 km to 1 km resolution using a weighting scheme of sea ice days ratio derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sea ice cover product that has a high correlation with the SIC. In a case study for Okhotsk Sea, the sea ice areas of both data (before and after downscaling) were identical, and the monthly means and standard deviations of SIC exhibited almost the same values. Also, Empirical Orthogonal Function (EOF) analyses showed that three kinds of SIC data (ERA-Interim, original AMSR2, and downscaled AMSR2) had very similar principal components for spatial and temporal variations. Our method can apply to downscaling of other continuous variables in the form of ratio such as percentage and can contribute to monitoring small-scale changes of sea ice by providing finer SIC data.

• International Area Studies Review
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• v.22 no.3
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• pp.175-200
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• 2018

Since the 1990s rising intangible asset has become one of the main driving forces of investment stagnation and jobless growth in advanced income countries. We investigate how does the impact of firms' profitability on employment growth depends on the intangibility and whether the relationship between profitability and tangibility has complementarity. With data on Korean firms over the period 1988~2017 we investigate the effects of intangibility and profitability on employment growth based on the econometric approach of system GMM. The empirical results are as follows. (1) the profit rate has gradually led to lower employment growth, while it had positive effect on employment before the period of financial crisis. The estimated values and signs of profit rate coefficients varies from traditional industries to high/medium tech. industries. (2) the effect of increasing asset intangibility ratio on employment growth is negative and statistically significant. (3) the coefficients of interaction term of (profit rate ${\times}$ intangibility ratio) have significant negative values. It means employment effect of profit rate are becoming higher(lower) as intangibility ratio is at the lower(higher) level; profits rate and intangibility are not complement with each other. The results imply that to boost employment industrial policy which has the capacity to coordinate business intangibility is preferred to expansionary demand policy.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.577-585
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• 2024

Infrastructure plays a crucial role in the industrial development and economic growth of a nation. However, recently, domestic infrastructure has been causing not only safety risks due to aging but also social and economic inefficiencies, increasing the need for maintenance. In particular, the deterioration rate of bridges is serious, so application of appropriate repair and rehabilitation methods and estimation of its quantity are required. In this study, frequently applied repair methods for bridges using data from the Facility Integrated Management System (FMS) were identified. the empirical correlation between damage volume and the repair volume was analyzed using Bridge Management System (BMS) data. The result of the analysis showed that the ratio of the repair volume to the damage volume was 1.0. The guideline, on the other hand, suggest 1.5 the ratio of the repair volume to the damage volume. Although the guidelines differently present more conservative figures considering safety, this study is significant in that it presents a practical ratio through data analysis results. This results can be used to develop a model that can calculate the amount of repair and rehabilitation of various facilities in the future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.55-67
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• 2024

This study aims to identify signals that can predict the quality of startups aiming to be listed on Korea's KOSDAQ market. The startups are divided into two groups: those backed by venture capital, where a third party has addressed information asymmetry, and those not backed by venture capital. The study seeks to identify signals to help select good companies for each group. The study primarily focuses on underpricing, which strongly correlates with company quality. It aims to investigate the causal relationship between underpricing and independent variables such as underwriter reputation, institutional investor competition rate, locked-up share ratio, and extended lockup period. The empirical analysis shows that IPOs with high institutional investor subscription competition, IPOs of start-ups without VC backing matched with reputable lead managers, and IPOs with high lockup shares of start-ups with VC backing are significantly underpriced. This study provides a theoretical and logical basis for strategically choosing the level of underpricing, considering the circumstances of the firm going public, mainly whether it is VC-backed or not, and considering the effectiveness of other signals mentioned above. It also opens the door for further research by researchers in other regions to study institutional investors' subscription ratio as the pre-listing signal that can help address information asymmetry. From a policymaker's perspective, the disclosure of the above information can be considered to reduce information asymmetry for investors.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.2
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• pp.61-72
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• 2019

Since the financial crisis in 1997, large scale unemployment and poverty have become serious, but there has been a surge in public and social job creation projects. However, with the limitations of low-wage and short-term jobs, the need for long-term, high quality jobs gradually began to garner attention. In recent years, social enterprises have grown both quantitatively and qualitatively and interest in social enterprises has increased; more specifically, scholars are interested in the determinants of success and failure of social enterprises in the academic field. In this study, we examined the effects of social enterprise characteristics on financial and social performance. In particular, we empirically analyzed social enterprises registered in the Korea Social Enterprise Agency. The financial performance of the social enterprise was measured using the net income ratio, operating income ratio, and the return on asset. The social performance of the social enterprise was measured by the total number of workers and the employment rate of vulnerable social groups. The characteristics of the social enterprise included CEO characteristics (gender, age, experience in operating the social enterprise), firm size, and the elapsed time of authentication. The results of the empirical analysis are as follows. First, as a result of analysis for the effect on financial performance, we found that the financial performance has a statistically significant, positive relationship with firm size, organizational form, government subsidies, and capital adequacy ratio. And we found that the social performance has a statistically significant, negative relationship with CEO age and credit debt dependence. Second, as a result of analysis for the effect on social performance, we found that the total number of workers had a significant, positive relationship with CEO gender and CEO age, as well as firm size, government subsidies; whereas the total number of workers had a significant, negative relationship with certification type and industry dummy. Comparatively, the employment rate of the vulnerable social groups had a significant, positive relationship with CEO gender and certification type, but there was no statistically significant relationship with the government subsidies or firm size.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.3
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• pp.157-167
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• 2016

The purpose of this study is to research, such as the following. And to the empirical results that affect the potential growth factors in the organization and development of human resources through staff training for enterprises to grow into a competitive enterprise. Through the analysis we propose a systematic training of the human resource development needs of the company. The results are as follows. First, the number of courses, the degree completion has had a positive effect on job satisfaction. Second, the number of courses can have a partial mediating effect on financial job satisfaction. Third, corporate education funding ratio has a negative effect and Business support form has a positive effect on turnover intentions. Fourth, the control variables of marital status has a positive effect on psychological job satisfaction and company size had a negative impact on turnover intention. The implications of this study are as follows. Organizational commitment to act as a mediating effect can be maximized through realistic training plan and quality training. There is also a need to be made a high quality education content development through the advancement of learning styles.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.24-33
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• 2016

Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations ($t_{au}=-0.143$, z = -0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- ($t_{au}=-0714$, z = -2.351, p = 0.0187) and after the construction ($t_{au}=-0.868$, z = -4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of "TSI(SD) - TSI(CHL)" against "TSI(TP) - TSI(CHL)" showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.6 no.4
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• pp.39-57
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• 2011

In this study, entrepreneurship opportunities, get in anywhere, in any situation, whether in respect to entrepreneurship through empirical research is to analyze. In addition, young entrepreneurs and entrepreneurship opportunities to target the source and a realistic opportunity to investigate the nature of the search in terms of effective support for young entrepreneurs and operational plans to seek the help. Entrepreneurship opportunities of the origins of the existing studies individually being taken were young entrepreneurs and selected for this study the national and international literature base, and objectives of the study to achieve the city "Young Entrepreneurs 1000 Project" participants, survey through the empirical foundation of their opportunities and entrepreneurship opportunities origins analyzed the relationship between sources. Source of entrepreneurship opportunities in the establishment will include the nature of existing research (intentional / unintentional), business opportunities generated background (source), business opportunity lead, business opportunity lead contact situation (the nature of chance encounters), the business idea was dealt with using here, a new source of opportunity factor established by adding the capital adequacy ratio of capital has been studied. Also 10 years ago by byeong-ju, Jo. entrepreneurship opportunities in Korea for the first time research on the relationship between the source after source of opportunities than in previous research literature on factors leading to the establishment an opportunity to add a set of relationships between sources were analyzed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.195-202
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• 2007

The normalized difference in incident solar energy between a target surface and a level surface (overheating index, OHI) is useful in eliminating estimation error of site-specific maximum temperature in complex terrain. Due to the complexity in its calculation, however, an empirical proxy variable called northern exposure index (NEI) which combines slope and aspect has been used to estimate OHI based on empirical relationships between the two. An experiment with real-world landscape and temperature data was carried out to evaluate performance of the NEI - derived OHI (N-OHI) in reduction of spatial interpolation error for daily maximum temperature compared with that by the original OHI. We collected daily maximum temperature data from 7 sites in a mountainous watershed with a $149 km^2$ area and a 795m elevation range ($651{\sim}1,445m$) in Pyongchang, Kangwon province. Northern exposure index was calculated for the entire 166,050 grid cells constituting the watershed based on a 30-m digital elevation model. Daily OHI was calculated for the same watershed ana regressed to the variation of NEI. The regression equations were used to estimate N-OHI for 15th of each month. Deviations in daily maximum temperature at 7 sites from those measured at the nearby synoptic station were calculated from June 2006 to February 2007 and regressed to the N-OHI. The same procedure was repeated with the original OHI values. The ratio sum of square errors contributable by the N-OHI were 0.46 (winter), 0.24 (fall), and 0.01 (summer), while those by the original OHI were 0.52, 0.37 and 0.15, respectively.