• 한국사회정책
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• v.20 no.2
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• pp.233-260
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• 2013

Despite various policies have been implemented to curb shadow education in Korea, it has continued to grow in recent two decades. This study investigates the expansion mechanism of shadow education focused on mobilization capabilities and market strategies of the suppliers. The success and failure of policy toward shadow education depends on how effectively it could block off the way by which the suppliers as the most important actors in politics of shadow education market mobilize consumers' anxieties. But shadow education policies have failed in two points. First, they have lacked honest intention to stop its proliferation. The Constitutional Court Decision Against Anti-Out-Of-School Classes Legislation of 2000 widened the windows of opportunity for the suppliers, and 5.31 educational reform of 1995 was neutral to their mobilization capabilities, though seemingly designed to control shadow education. This policy orientation, which reflected neoliberal Gesinnungsethik defective of Verantwortungsethik, stimulated shadow education to expand in that suppliers' mobilization capabilities were reinforced or remained intact. Second, shadow education suppliers have succeeded in mobilizing the desire and anxiety of potential consumers. To cope with government's policy including improving the qualities of public education, realignment of college entrance systems, and meeting the shadow education needs, they have developed various market strategies such as management of existing demands, creation of responsive demands, and squeezing out new demands. They have succeeded in nullifying policies by employing or mixing strategies with effect. Policy decisions in the future need to be made with reference to Verantwortungsethik, and be more cautious to socio-political contexts of Korea, to mobilization capabilities and market strategies of the suppliers in particular.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.63-70
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• 2009

Recently, in the security token based authentication system, there is an increasing trend of using fingerprint for the token holder verification, instead of passwords. However, the security of the fingerprint data is particularly important as the possible compromise of the data will be permanent. In this paper, we propose an approach for secure fingerprint verification by distributing both the secret and the computation based on the fuzzy vault(a cryptographic construct which has been proposed for crypto-biometric systems). That is, a user fingerprint template which is applied to the fuzzy vault is divided into two parts, and each part is stored into a security token and a server, respectively. At distributing the fingerprint template, we consider both the security level and the verification accuracy. Then, the geometric hashing technique is applied to solve the fingerprint alignment problem, and this computation is also distributed over the combination of the security token and the server in the form of the challenge-response. Finally, the polynomial can be reconstructed from the accumulated real points from both the security token and the server. Based on the experimental results, we confirm that our proposed approach can perform the fuzzy vault-based fingerprint verification more securely on a combination of a security token and a server without significant degradation of the verification accuracy.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.49-60
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• 2020

The number of traffic control equipment installed to prevent traffic accidents increases every year due to continuous installation by the National Police Agency and local governments. However, it is installed based on qualitative judgment rather than engineering analysis results. The purpose of this study was to present additional installations in the future by presenting the installation criteria considering the severity of accidents for each road type and calculating the appropriate number of installations. ARI indicators that can indicate the severity of traffic accidents were developed, and road types were classified through analysis of variance and cluster analysis, and accident information by road type was analyzed to derive ARI of clusters with high traffic accident severity. The ARI values required to determine the installation of equipment for each road type were presented, and 5,244 additional installation points were analyzed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.1
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• pp.49-61
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• 2021

The repeated shipboard measurements that have been conducted by the National Institute of Fisheries Science (NIFS) for more than a half century, provide the valuable long-term hydrographic data with high spatial-temporal resolution. However, this unprecedent dataset has been rarely used for oceanic climate sciences because of its reliability issue. In this study, temporal variability of salinity error in the NIFS data was quantified by means of extremely small variability of salinity in the deep layer of the south-western East Sea, in order to contribute to studies on long-term variability of the East Sea. The NIFS salinity errors estimated on the isothermal surfaces of 1℃ have a remarkable temporal variation, such as ~0.160 g/kg in the year of 1961~1980, ~0.060 g/kg in 1981~1994,~0.020 g/kg in 1995~2002, and ~0.010 g/kg in 2003~2014 on average, which basically represent bias error. In the recent years, even though the quality of salinity has been improved, there still remain relatively large bias errors in salinity data presumably due to failure of salinity sensor managements, especially in 2011, 2013, and 2014. On the contrary, the salinity in the year of 2012 was very accurate and stable, whose error was estimated as about 0.001 g/kg comparable to the salinity sensor accuracy. Thus, as long as developing proper data quality control procedures and sensor management systems, I expect that the NIFS shipboard hydrographic data could have good enough quality to support various studies on ocean response to climate variabilities. Additionally, a few points to improve the current NIFS shipboard measurements were suggested in the discussion section.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.561-571
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• 2020

Seven techniques widely used in the geodetic transformations have been reviewed and compared to figure out their theoretical characteristics. A series of numerical tests were performed about four data sets. This was followed by result analyses in terms of transformation residuals and accuracies together with some hypothesis testings based on the student-t distribution to confirm the statistical significance of the techniques. In the case of the transformation between the geodetic frames implemented in the same system, no statistical significance was revealed in the results of the 3D transformation techniques, even if the testing area becomes large as the Asia-Oceania continent. Among the 2D transformations, it was possible for the NTv2 grid modeling technique to deliver improved transformation accuracy. Finally, it was possible from the results analyzed in this study to propose the Helmert transformation to geodetic control points and the NTv2 technique to the 2D spatial data transformation of the geodetic systems.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1393-1405
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• 2020

UAV (Unmanned Aerial Vehicle) can acquire high-resolution images due to low-altitude flight, and it can be photographed at any time. Therefore, the UAV images can be updated at any time in map production. Due to these advantages, studies on the possibility of producing large-scale digital maps using UAV images are actively being conducted. Precise digital maps can be used as base data for digital twins or smart cites. For producing a precise digital map, precise sensor modeling using GCPs (Ground Control Points) must be preceded. In this study, geometric models of UAV images were established through a precision sensor modeling algorithm developed in house. Then, a digital map by stereo plotting was produced to evaluate the possibility of large-scale digital map. For this study, images and GCPs were acquired for Ganseok-dong, Incheon and Yeouido, Seoul. As a result of precision sensor modeling accuracy analysis, high accuracy was confirmed within 3 pixels of the average error of the checkpoints and 4 pixels of the RMSE was confirmed for the two study regions. As a result of the mapping accuracy analysis, it satisfied the 1:1,000 mapping accuracy announced by the NGII (National Geographic information Institute). Therefore, the precision sensor modeling technology suggested the possibility of producing a 1:1,000 large-scale digital map by UAV images.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1615-1627
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• 2020

The purpose of this study is to compare and analyze the performance of KOMPSAT-3 Digital Surface Model (DSM) made in overseas testbed area. To that end, we collected the KOMPSAT-3 in-track stereo image taken in San Francisco, the U.S. The stereo geometry elements (B/H, converse angle, etc.) of the stereo image taken were all found to be in the stable range. By applying precise sensor modeling using Ground Control Point (GCP) and DSM automatic generation technique, DSM with 1 m resolution was produced. Reference materials for evaluation and calibration are ground points with accuracy within 0.01 m from Compass Data Inc., 1 m resolution Elevation 1-DSM produced by Airbus. The precision sensor modeling accuracy of KOMPSAT-3 was within 0.5 m (RMSE) in horizontal and vertical directions. When the difference map was written between the generated DSM and the reference DSM, the mean and standard deviation were 0.61 m and 5.25 m respectively, but in some areas, they showed a large difference of more than 100 m. These areas appeared mainly in closed areas where high-rise buildings were concentrated. If KOMPSAT-3 tri-stereo images are used and various post-processing techniques are developed, it will be possible to produce DSM with more improved quality.

• Nutrition Research and Practice
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• v.16 no.1
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• pp.74-93
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• 2022

BACKGROUND/OBJECTIVES: There has been an increased interest in determining calcium magnesium, sodium, and potassium's distinct effects on hypertension over the past decade, yet they simultaneously regulate blood pressure. We aimed at examining the association of dietary calcium, magnesium, sodium, and potassium independently and jointly with hypertension using National Health and Nutrition Examination Survey data from 2007 to 2014. MATERIALS/METHODS: The associations were examined on a large cross-sectional study involving 16684 US adults aged>20 years, using multivariate analyses with logistical models. RESULTS: Sodium and calcium quartiles assessed alone were not associated with hypertension. Potassium was negatively associated with hypertension in the highest quartile, 0.64 (95% confidence interval [CI], 0.48-0.87). When jointly assessed using the high and low cut-off points, low sodium and corresponding high calcium, magnesium, and potassium intake somewhat reduced the odds of hypertension 0.39 (95% CI, 0.20-0.76). The sodium-to-potassium ratio was positively associated with hypertension in the highest quartile1.50 (95% CI, 1.11-2.02). When potassium was adjusted for sodium intake and sodium-to-potassium ratio assessed among women, increased odds of hypertension were reported in the highest quartile as 2.02 (95% CI, 1.18-3.34) and 1.69 (95% CI, 1.12-2.57), respectively. The association of combined minerals on hypertension using dietary goals established that men meeting the reference intakes for calcium and exceeding for magnesium had reduced odds of hypertension 0.51 (95% CI, 0.30-0.89). Women exceeding the recommendations for both calcium and magnesium had the lower reduced odds of 0.30 (95% CI, 0.10-0.69). CONCLUSIONS: Our results suggest that the studied minerals' association on hypertension is stronger when jointly assessed, mostly after gender stratification. As compared to men, women increased their risk of hypertension even with a low sodium intake. Women would also reasonably reduce their risk of developing hypertension by increasing calcium and magnesium intake. In comparison, men would somewhat be protected from developing hypertension with calcium intake meeting the dietary goals and magnesium exceeding the nutritional goals.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.3
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• pp.187-193
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• 2022

In the Yeongdong region of Gangwon-do, coastal areas are important resources in terms of cultural, social and economic aspects. However, the coast of Gangwon-do is experiencing severe erosion, and it is concerned that its adverse effects will gradually increase. In this study, coastline changes of Yangyang and Gangneung in Gangwon-do were tracked and analyzed over a long period of time. In order to build time series image data, aerial photos from the 1940s to the present were mainly used, and data from CORONA satellite, which operated from the 1960s to the early 1970s, were collected and used together. Using 51cm resolution ortho image and 2m resolution Digital Elevation Model(DEM) as reference, ground control points were selected to perform geometric correction on the aerial photos and CORONA images. Subsequently, Canny edge detector applied to these images to extract the coastlines. As a result of analyzing the extracted and vectorized coastlines by overlaying them in chronological order, erosion and deposition occurring around the artificial structures and on the nearby beaches were observed. In this study, the effect of seasonal variation, tide, and various coastal management including the beach filling were not considered. Because coastal erosion is greatly affected by geographic factors, each local government must find its own solution. Continuous research and local data accumulation are required.

• Journal of Life Science
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• v.31 no.12
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• pp.1072-1078
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• 2021

The oral pathogen Streptococcus mutans is considered a major causative agent of dental caries in humans. The use of dental hygiene products, including toothpaste and mouthwash, is used for caries control. However, food intake can lead to the recurrence of oral microorganisms. This study aimed to explore why this bacterium dies so quickly during prolonged incubation and to assess whether this growth characteristic is closely associated with the secretion of metabolic products. Notably, the number of live S. mutans cells rapidly declined after 24 hr during the entire period tested, whereas the number of Escherichia coli cells, an indicator strain, remained steady over the same period. To test whether the S. mutans supernatants contained possible signals that accelerated the death of neighbor cells, we obtained the individual supernatants at the above time points. Following pH neutralization, the cells in which the supernatant was supplemented with glucose grew well. However, pH adjustment alone could not fully recover cell growth in conditions in which the supernatant was supplemented, with or without glucose. These phenotypes of S. mutans may be associated with signaling, not only resulting from nutrient depletion. The findings on the survival phenotype of S. mutans provide new insights into cell-cell communication in the biology of this bacterium.