• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1773-1784
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• 2021

In order to minimize damage to oil spill accidents in the ocean, it is essential to collect a spilled area as soon as possible. Thus satellite-based remote sensing is a powerful source to detect oil spills in the ocean. With the recent rapid increase in the number of available satellites, it has become possible to generate a status report of marine oil spills soon after the accident. In this study, the oil spill area was calculated using various satellite images for the Symphony oil spill accident that occurred off the coast of Qingdao Port, China, on April 27, 2021. In particular, improving the accuracy of oil spill area determination was applied using high-resolution commercial satellite images with a spatial resolution of 2m. Sentinel-1, Sentinel-2, LANDSAT-8, GEO-KOMPSAT-2B (GOCI-II) and Skysat satellite images were collected from April 27 to May 13, but five images were available considering the weather conditions. The spilled oil had spread northeastward, bound for coastal region of China. This trend was confirmed in the Skysat image and also similar to the movement prediction of oil particles from the accident location. From this result, the look-alike patch observed in the north area from the Sentinel-1A (2021.05.01) image was discriminated as a false alarm. Through the survey period, the spilled oil area tends to increase linearly after the accident. This study showed that high-resolution optical satellites can be used to calculate more accurately the distribution area of spilled oil and contribute to establishing efficient response strategies for oil spill accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3999-4008
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• 2012

This study investigated the symptoms of work-related musculoskeletal disorder(WMSDs) for physical therapists who have different work duties. We analyzed the symptoms in the musculoskeletal system and the degree of work-harmfulness by the survey of the symptom in the musculoskeletal system and rapid upper limb assessment(RULA) for pain control group(n=56), adult exercise group(n=53), and pediatric exercise group(n=22). As a result, 69.6% of the pain control group, 84.9% of the adult exercise group, 81.8% of the pediatric exercise group show the observable symptom. The adult exercise group has the biggest work load per hour in the final wrist & arm score of the ergonomic risk assessment using RULA. The action level of the pain control group is $3.0{\pm}0.9$; the Action Level of adult exercise group is $3.3{\pm}0.6$; the Action Level of the pediatric exercise group is $3.2{\pm}0.8$, and so it is shown that the adult exercise group has a problem of working posture. It is considered that devices and education system for preventing from WMSDs should come into wide use.

• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.835-846
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• 2020

Recent severe climate changes and extreme weather events have caused the uncommon types of forest ecosystem disturbances such as hails and gypsy moths. This paper describes the analysis of the forest ecosystem disturbances using ISODATA (Iterative Self-organizing Data Analysis Technique Algorithm) with the RapidEye and Sentinel-2 images, regarding the cases of the hail damages in Hwasun in 2017 and the gypsy moth damages in the Chiak Mountain in 2020. In the case of hail damages, the comparison of the June image of this study and the July field survey of the previous study showed that the damage severity increased from June to July as the drought overlapped after the trees were injured by the hails. In the case of gypsy moths, significant leaf damages were found from the image of June, and the damages were mainly distributed at the low-altitude slope near Wonju City. We made sure that satellite remote sensing is a very effective method to detect various and unusual forest ecosystem disturbances caused by climate change. Also, it is expected that the Korean Medium Satellite for Agriculture and Forestry scheduled to launch in 2024 can be actively utilized to monitor such forest ecosystem disturbances.

• Journal of the Korean association of regional geographers
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• v.13 no.1
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• pp.43-53
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• 2007

Rapid geomorphic changes occur in Nakdong River deltaic coast which is composed of deltaic barrier islands and tidal flats. We investigate the pattern of these rapid geomorphic changes by analyzing the distributions of sediment grain size characteristics. The distributions of sediment grain size characteristics analysis is a very efficient method to explain geomorphic changes of deltaic barrier islands. In sediments from Jinwoo Island, Sinja Island, and Doyo Island which are composed of Nakdong River deltaic coast, mean particle size increases to onshore direction and become coarser in tidal inlets. All sediments are very well sorted. Though almost sediments show little negative skewness, several sediments from tidal inlets show negative skewness. These results provide that the stronger and more regular energies affect Nakdong River deltaic coast and make fine sediments selectively move toward tidal inlets. Because of this mechanism, the recurved spits of deltaic barrier islands enlarge.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.7-14
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• 2005

Traffic congestion causes enormous social costs as well as loss of travel time and waste of energy. Though the Seoul metropolitan government implemented various forms of transportation policies such as urban road pricing and public transportation reform, traffic volume which across the Seoul metropolitan borders have greatly increased because of housing land development in suburban area. The purpose of this study is to estimate individual's willingness-to-pay(WTP) for extensive implementation of congestion pricing through policy-mix with bus rapid transit(BRT) system. So the field survey interviews carried out. The empirical analysis was done with priority given to the following two topics; derivation of individual WTP and prior evaluation of policy effect from the equity aspect. To estimate individual WTP, we adopted contingent valuation method (CVM). The former is to estimate individual WTP for respondent's maintaining his/her transit pattern when he/she is faced with congestion pricing by using compensating variation(CV) concept. And, the latter aims at evaluating policy effect from the equity aspect by calculating the Proportion of WTP to average income using WTP in income bracket for policy scenarios.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.113-122
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• 2007

The rapid growth of aerial survey and remote sensing technology has enabled the rapid acquisition of very large amounts of geographic data, which should be analyzed using real-time visualization technology. The level of detail(LOD) algorithm is one of the most important elements for realizing real-time visualization. We chose the triangulated irregular network (TIN) method to generate normalized digital elevation model(DEM) data. First, we generated TIN data using contour lines obtained from a two-dimensional(2D) digital map and created a 2D grid array fitting the size of the area. Then, we generated normalized DEM data by calculating the intersection points between the TIN data and the points on the 2D grid array. We used constrained Delaunay triangulation(CDT) and ray-triangle intersection algorithms to calculate the intersection points between the TIN data and the points on the 2D grid array in each step. In addition, we simulated a three-dimensional(3D) terrain model based on normalized DEM data with real-time visualization using a Microsoft Visual C++ 6.0 program in the DirectX API library and a quad-tree LOD algorithm.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.1
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• pp.225-235
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• 2020

The Korean government is attempting to promote technology-based start-ups and venture firms that can lead to new national growth engines being developed. Although government support policies focus on improving survival rates, strategic tools for sustainability management based on a continuing company's assumption are also relevant. Previous studies indicate corporate social responsibility (CSR) as an important strategic tool for the management of corporate sustainability. This research is an exploratory study that seeks to empirically analyze the applicability of such CSR to venture firms. Existing previous studies have been carried out by large companies and surveys, and there are limitations that do not reflect the characteristics of companies. To complement the shortcomings of previous studies and propose practical consequences, this study conducted an empirical analysis using raw data from government approval statistics to identify the growth stages of venture firms. Using the 2018 Survey of Korea Venture Firms, we identified the growth stages of domestic venture firms and used the data envelopment analysis (DEA) to investigate the effect of CSR activities on managerial efficiency. The analysis found that CSR during start-up and early growth cycles did not affect managerial performance. The organization that conducted enthusiastic CSR activities performed better than those that did not perform CSR activities since the rapid growth era. Ultimately, the scale efficiency of venture business was the highest from the rapid growth era when the CSR was not done. This study is a pioneering study that found that after the period of high growth, venture firms' CSR activities can affect managerial performance. Therefore, it is important to advise applicable policies and business decision-makers that CSR practices can be a tactical resource for improving performance of management.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.247-254
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• 2017

ELISA has been used for the diagnosis of toxoplasmosis, but it is being gradually replaced by a rapid diagnostic test (RDT). We compared and analyzed ELISA and RDT results using the sera collected during 4 consecutive years from residents of Gyodong-do (Island), Incheon-city, Korea. Sera from 921, 993, 940, and 838 adult residents were collected on a yearly basis (2010-2013). ELISA was performed by using a crude extract of T. gondii RH strain antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera. Comparison between groups was analyzed by the Student's t-test. The positive seroprevalence surged from 14.7% (135/921, 2010), 23.1% (231/993, 2011), 23.6% (222/940, 2012), and 32.1% (269/838, 2013) by ELISA. In contrast, RDT showed a more moderate increasing trend from 21.7% (200/921, 2010), 25.5% (253/993, 2011), 28.9% (272/940, 2012) and 33.1% (277/838, 2013). Discrepancies between ELISA and RDT were noted near the cut-off value. At the OD 0.15-0.24 range, RDT could detect 16.1% (169/1051) more positives, which suggests an early or acute toxoplasmosis, but at the OD 0.25-0.34 range, ELISA could detect 35.9% (92/256) more positives of possible chronic infections. Over the OD > 0.35 ELISA and RDT agreed in the majority of the cases. This surge in seroprevalence may be caused by the organic agriculture in addition to eating behavior or increase in pets among Koreans. These facts may be applied on a full-scale national survey using RDT to supplement ELISA to define the characteristics of the infection.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.68-79
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• 2012

Korea was followed by a rapid increase in road construction investment in late 1980s with the help of strong economic conditions. As a result of such investment, it will be expected that there must be a rapid increase in demand for maintenance or rehabilitation of the facilities after 2010. We are developing asset management information systems for enhancing user's satisfaction and innovating the facility management techniques within a limited budget. We suggested the assessment items for the Level of Service for tunnel facility's operation and maintenance(O&M), in this study. We have surveyed for the importance of assessment items by considering both user's viewpoints and facility management agency's viewpoints. We came to realize the relative importance of the items based on this survey using the Analytic Hierarchy Process(AHP) method proposed by Satty. The relative importance of assessment items in terms of the user's viewpoint was identified in descending order such as safety, mobility, accessibility, convenience, O&M efficiency, comfort, rural revitalization, environment, and information. Also, the importance of the items in terms of the management agency's viewpoint was identified in descending order such as safety, mobility, accessibility, environment, rural revitalization, convenience, O&M efficiency, information, and comfort. It means that safety of tunnel facilities is more important than mobility, although which is the basic function of the road facility, both in agency's and user's concern. Therefore, the agencies have to pay more attentions and efforts to ensure safety of tunnel facilities when they establish the investment plans for the tunnel facility O&M.

• Korean Journal of Social Welfare
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• v.56 no.4
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• pp.57-78
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• 2004

The economic crisis in $1997{\sim}1998$ caused massive unemployment and unprecedentedly increased the number of the poor in Korea. As many unemployed families fell into poverty, the poverty rate skyrocketed to higher than 10 percent. Not later than 2000, unemployment late got back to normal and real average income among urban households approached to the income level prior to the economic crisis. Although the economic crisis has been passed through, poverty was not decreased to the low level prior to the crisis by 2000. Why does it remain high? This study attempts to provide an answer to this question by analysing the poverty trend over the 1990s. Data come from the National Survey of Household Income and Expenditures 1991, 1996, and 20001. Results show that poverty was rapidly reduced in the first half period of the 1990s. This reduction in poverty is largely explained by steady and rapid economic growth. Modest improvement in income inequality also contributed. In contrast, the poverty rate considerably increased in the latter half of the 1990s. Average income was not fully recovered to its prior level, which reflected the economic crisis and the subsequent economic stagnation. Worsened income inequality led to higher poverty rate too. In addition, demographic changes increased the share of economically vulnerable types of families, such as families headed by single parents and the elderly. The most significant factor in explaining the higher poverty rate was extended income differential among non-elderly adults, while the next was the increased number of the elderly families. Yet, findings a little differ depending on which concepts of poverty to adopt. In the analyses based on the concept of absolute poverty, economic growth the most significantly affected the poverty trends in the 1999s. Changes in income inequality played the most important role in explaining the trend in relative poverty. Adopting the concepts of quasi-absolute poverty, which is preferred in this study, results show that rapid economic growth significantly reduced poverty in the first half of the 1990s and both worsened income inequality and stagnated economic growth increased poverty in the latter 1990s.