• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.107-114
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• 2002

The cadastral surveying is essential for the effective management of a country, the D/B building of NGIS. Many of GPS applications require a positioning accuracy of several centimeters for rover in real-times. But, to achieve higher positioning accuracies in real-time, the double differencing technique should be implemented using carrier phase data. Corrected observations at the reference station can be transmitted and used to form double difference observations at the rover using a data link. In this study, the area accuracy of cadastral survey using the RTK GPS will be assessed, and will produce area of parcel of land. As the result of comparison among area by TS, planer surveying and RTK GPS. parcels-register for site is analyzed by this data. The results show that mean error of area calculated min. $2.42m^{2}{\sim}\;max.\;13.69m^{2}$ and RMSE calculated min. $0.00329\;{\sim}\;max.\;0.01846$.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.32-42
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• 1990

The method using Rankine Soure distribution over the hull surface and undisturbed free surface was applied to calculate the free surface flow around a ship. The ship hull as well as a local portion of the undisturbed free surface arc geometrically represented by quadrilateral panels and the source density is determined so as to satisfy the linearized free surface condition based on the double model flow. The pressure distribution, wave resistance, wave profile and hydrodynamic sinkage force and trim moment for the Wigley hull and the Series 60 hull with $C_B=0.60$ were calculated in the fixed condition. The calculated results were compared with the measured values. The dependance of the solution on the panel arrangement, particularly on the free suraface, was also studied through 11 numerical test cases for the Wigley hull.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.69-80
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• 2013

This study evaluates the seismic performance of road tunnels designed before the provisions for seismic design of tunnels were first established in 1999. Extensive design data and site investigation reports are investigated to select tunnels sections that are considered to be most susceptible to seismically induced damage under earthquake loading. Detailed analyses are performed on selected tunnels. The methods used are method of displacement and dynamic analysis. In performing the method of displacement, which is a type of pseudo-static analysis method used for underground structures, full domain and reduced domain modeling were used. The dynamic analyses are performed using finite difference method and using nonlinear constitutive model. Comparisons show that the reduced domain method of displacement match very closely with the dynamic analysis, demonstrating that it is the most suitable method for evaluating the seismic performance of road tunnels built in rocks. It is also shown that road tunnels, for which seismic design were not applied, are safe under the seismic risks corresponding to an earthquake with a return period 1000 years. It is concluded that additional seismic retrofit of tunnels is not necessary.

• Environmental and Resource Economics Review
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• v.27 no.1
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• pp.161-194
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• 2018

This study examines performances of cooperatives relative to investor-owned firms in the US electric power industry. Using a panel data of firms from 2001 to 2014, the results show that cooperatives operate under conditions of more difficult capital constraints associated with the higher cost of debt and limited access to external equity capital. While investor-owned utilities, especially the large utilities that are less capital constrained, take benefits from substantial scale economies existing in the industry, the marginal cost of operation substantially increases with output for cooperatives. I do not find differences in profitability between the two ownership structures, measured by return on assets and return on equity. Plant capacity utilization, which is a measure of plant efficiency conditional on the operation, is also not statistically different between the two groups.

• The Journal of the Korea Contents Association
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• v.19 no.4
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• pp.54-62
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• 2019

With regard to industrial accidents, large corporations and public institutions are continuously reducing disasters through systematic management. However, industrial accidents continue to increase in small-scale workplaces. In order to ensure the safety of workers, the government supports the purchasing of industrial accident prevention equitments through financial support projects for small business. However, despite the financial support, the effectiveness of the project is hardly verified. In this study, we analyze the policy effectiveness of the financial support program for industrial accident prevention in a small-scale workplace using the difference-in-difference method. To achieve research purposes, we used the data on the occurrence of industrial accidents, the status of workplaces by year and the data on the status of workplace benefiting from financial support program for the past 10 years. This study is significant in that it analyzed the net effect of financial support programs for disaster reduction in the small business site.

• 한국사회정책
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• v.23 no.1
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• pp.179-202
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• 2016

This study analyses the effects of the major educational policies, focusing on the private tutoring prohibition policy(PTPP), on the intergenerational class mobility(ICM) by using Korea Labor and Income Panel Study(KLIPS) 1st-12th surveys. Because private tutoring(shadow education) can be effective for academic achievement of children of above middle classes that spend most private tutoring expenditure and have more information on education, the private tutoring prohibition policy can increase the intergenerational mobility. This study confirms this possibility. Even when the overlapping effect of the middle school equalization polity is controlled for, there is still high effect of the PTPP. We think that we still need to examine the level of intergenerational mobility with PTPP cohort with that of later cohorts in the future. We also emphasize the compositive effect of the several consistent policies such as middle school and high school equalization polices and the PTPP and length and continuity of the policies for the higher mobility.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.697-705
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• 2015

This paper proposes a high-speed and high-quality haze removal method based on dual dark channels. In the conventional method, the halo artifacts are suppressed by the additional transmission refinement, but the transmission refinement is computationally intensive and the quality of the haze removal is sometimes unsatisfactory because of the residual halo artifacts. In the proposed method, the transmission is estimated with the mixture of the two dark channels with different window size. By mixing the two dark channels so as to avoid the halo artifacts, the proposed method realizes a high-quality haze removal even without the transmission refinement. Experimental results demonstrate that the quality of the results by the proposed method is superior to those by the conventional method and the speed of the haze removal is about 14.2 times higher than that of the conventional method.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.3
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• pp.223-231
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• 2020

Governments and private companies have established various local entrepreneurial infrastructure institutions in most regions in order to reduce youth unemployment, and boost youth entrepreneurship and regional employment. However, previous studies has been limited to explore the impact of the entrepreneurial infrastructure institutions on the willingness of start-up entrepreneurs. Thus, the main purpose of this study is to fill in the gaps of the research, identify the effect of the entrepreneurial infrastructure institutions on regional employment focusing on the Partner Squares which are entrepreneurial infrastructure institutions in several regions and established by N company, and set a foundation for further research regarding the effectiveness of the entrepreneurial infrastructure institutions. In order to verify the effectiveness of the Partner Squares on the local employment, we use the raw data of the Economically Active Population Survey (Statistics Korea) and analyze the effectiveness by using the Difference-in-Differences model. The main findings are as follows. While the Partner Square Seoul has not statistically influenced on the employment of local youth workers, the Partner Square Busan has increased about 3% of the average number of employees (575 thousand) from May 2017 to July 2019, increasing the number of local youth workers by 17,000. Also, after the establishment of the Partner Square Gwangju, the institution has increased 4,500 local employees, which is about 1.7% of the average number of employees (267,000) from September 2018 to July 2019. This implies that the Partner Squares provide a variety of effective start-up education programs and networks for pre-starters and founders in the region, thereby helping them to grow and boosting the local employment. An important implication is that by using government statistical data, we find roles of entrepreneurial infrastructure institutions to revitalize local economy and employment. In future studies, studies need to be conducted considering various exogenous variables that can affect local employment, such as the government industrial policies and entrepreneurial infrastructure institutions other than the Partner Squares.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.76-88
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• 2017

The urban park plays important roles in protecting the urban landscape and improving citizens' health, recreation, and the emotional life. Above and beyond these roles, the urban park is expected to rearrange urban spatial structures as a kind of urban system. The purpose of this paper is to identify empirically to change urban spatial structures by construction of the urban park. This study regards gentrification around the urban park as a process to change urban spatial structures. The gentrification means the regeneration and upgrading of deteriorated urban property by the middle class or commercial developers. The site of case analysis is the Seoul Forestry Park in Sungdong-gu, Seoul. The Seoul Forestry Park is regarded as a representative urban park of Seoul, and caused gentrification around park after the 2005 opening. This study operationally defines the gentrification index and the accessibility index from an urban park and offers an empirical analysis of relation among the urban park, the gentrification and urban spatial structure in a statistic district which is the minimum unit of Korean statistic data in 2000, 2005, and 2010, using Difference-in-Difference method and linear probability model. The results of this empirical study show that the Seoul Forestry Park changes urban spatial structures by gentrification. It reverses a trend of migration of gentrifiers before and after construction of the Seoul Forestry Park. It suggests urban park construction as an alternative method for urban regeneration by inducing the middle class into the inner city of Seoul.

• Investigative Magnetic Resonance Imaging
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• v.9 no.2
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• pp.94-100
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• 2005

Purpose : This study was designed to evaluate the usefulness of 3T-TOF MR angiography (3T-TOF MRA) compared with transcranial Doppler sonography (TCD) and conventional angiography (CA) in patients with suspected cerebral infarction. Materials and Methods : Fifty four patients with clinical symptoms of cerebral infarction were involved in this study, and had undergone 3T-TOF MRA and TCD, with CA in 11 patients. On the basis of divisions of the carotid artery, four groups were designated: group I, both vertebral arteries and basilar artery; group II, segment between 2 cm below bifurcation of common carotid artery and genu portion of internal carotid artery; group III, segment between petrous portion of internal carotid artery and bifurcation of anterior and middle cerebral artery; group IV, from bifurcation of anterior and middle cerebral artery to thier distal branches. Two radiologists retrospectively reviewed the vascular imaging and stenosis in 3T-TOF MRA, TCD, and CA. Results : A total of 432 arteries, 108 in each group, were available. The assessment of vascular imaging quality in 3T-TOF MRA is scored 2.98, 2.96, 2.91, 2.88 in 4 groups, respectively. Agreement among 3T-TOF MR angiography, TCD, and CA was high. Conclusion : 3T-TOF MR angiography may be useful method for the assessment of stenotic lesions of cranial vasculature in patients with cerebral infarction.