• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.2
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• pp.139-147
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• 2008

The positioning accuracies tend to deteriorate as the distance between the rover and the reference station increases in the Real-Time Kinematic (RTK) surveys using Global Positioning System (GPS). To solve this problem, the National Geographic Information Institute (NGII) of Korea has installed Virtual Reference System (VRS), which is one of the network-based RTK systems. In this study, we conducted the accuracy tests of the VRS-RTK surveys. We surveyed 50 control points inside the NGII's GPS Continuously Operating Reference Stations (CORS) network using the VRS-RTK system, and compared the results with the published coordinates to verify the positioning accuracies. We also conducted the general RTK surveys at the same control points. The results showed that the positioning accuracy of the VRS-RTK was comparable to that of the general RTK, because the horizontal positioning accuracy was 3.1 cm while that of general RTK was 2.0 cm. Also the vertical positioning accuracy of VRS-RTK was 6.8 cm.

• Korea journal of population studies
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• v.29 no.2
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• pp.195-213
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• 2006

Follow-up surveys with 700 smoking male adults and 300 nonsmoking male adults were performed before 20-days and after one month, three months and six months since government's price increase enforcement. 572 smokers among 700 and 198 non-smokers among 300 were remained and followed up till the end of the surveys. The cessation rate of smokers are 6.6%(after one month), 10.3%(after three months) and 11.0%(after six months). Smoking cessation ratio of new smoking quilters who considered that price increase as a motive of their giving-up smoking are 76.3%, 81.3% and 65.1%. The smokers estimates of short-run price elasticities from follow-up surveys are -0.6853, -0.6230 and -0.5482 at each survey period. Including non-smokers, estimates of short-run price elasticities from follow-up surveys are -0.3920, -0.3739 and -0.3481 at each survey period. The effect of demand decrease caused by KR\500 price increase stayed with little difference for six months because price elasticities between each survey period showed no much change. Effectiveness and validity of tobacco control by price increase was confirmed through the survey results. Therefore if the government want to attain long term strategic goal to decrease general smoking rate among male adult smokers by 30%, the strong smoking prohibition policy, just like the price increase of December 2004, should be continuously driven.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.50-59
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• 2001

Since 1998, government-led Korean venture business boom now proceeds into the stage of market-oriented venture business growth. At such a moment, this research is to clarify the relations between the Critical Success Factors of Korean venture businesses, based on domestic and foreign literature surveys and inquiry surveys over domestic venture capitalists. This research starts from the necessity to overcome the limits of the existing researches by uni-dimensional Korean venture businesses and to manifest the multi-dimensional relations between the success factors from the various viewpoints. And this research adopts System-Dynamics methodology to manifest and utilize relations among those factors, avoiding the existing metrical approaches. This research can be called a new approach to the current ecosystems of Korean venture in which whether venture businesses in Korea succeed is considered to depend on the list on the stock market. For this, this research implemented verification analysis through the simulations of each factor at various levels to build causality map which clarifies the causality of success factors of venture businesses through the System-Dynamics methodology and to utilize it as a way of support to decision-making of venture businesses. This research will be able to suggest the reactions depending on various internal and external situations. This research tried to manifest the causality map of each factor on the basis of inquiry surveys and literature surveys to clarify Feedback among each factor by the SD methodology and simulate it. This research will be a basis to establish the chance to bolster up the still fragile probing research into success factors of substructure of venture businesses through the suggestion of possibility as an efficient analysis framework via the verification of SD methodology and the utilization of results of this research.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.211-221
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• 2017

Ellipsodially referenced survey (ERS) is considered as one of the challenging issues in the hydrographic surveys due to the fact that the bathymetric data collected by this technique can be readily transformed either to the geodetic or the chart datum by application of some geoscientific models. Global Navigation Satellite Systems (GNSS) is a preferred technique to determine the ellipsoidal height of a vessel reference point (RP) because it provides cost-effective and unprecedentedly accurate positioning solutions. Especially, the GNSS-derived heights include heave and dynamic draft of a vessel, so as for the reduced bathymetric solutions to be potentially free from these corrections. Although over the last few decades, differential GNSS (DGNSS) has been widely adopted in the bathymetric surveys, it only provides limited accuracy of the vertical component. This technical barrier can be effectively overcome by adopting the so-called GNSS carrier phase (CPH) based techniques, enhancing accuracy of the height solution up to few centimeters. From the positioning algorithm standpoint, the CPH-based techniques are categorized under absolute and relative positioning in post-processing mode; the former is precise point positioning (PPP) correcting errors by the global or regional models, the latter is post-processed kinematic positioning (PPK) that uses the differencing technique to common error sources between two receivers. This study has focused on assessment of achievable accuracy of the ellipsoidal heights obtained from these CPH-based techniques with a view to their applications to hydrographic surveys where project area is, especially, few tens to hundreds kilometers away from the shore. Some field trials have been designed and performed so as to collect GNSS observables on static and kinematic mode. In this paper, details of these tests and processed results are presented and discussed.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.4
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• pp.185-190
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• 1997

Electrical surveys were conducted at the Seokdae waste landfill in July,1996. Within the landfill, 4 lines of dipole-dipole surveys and 7 Schlumberger soundings were carried out and 2 soundings in front of the landfill. In the landfill, interpretations of the survey data show low resistivity zones below 10 Ωm to a depth of 50 m from the surface and such low resistivity zones of the D block are thicker than those of the other blocks by about 2~10 m. Considering the depth of the bedrock and the height of waste reclamation, no evidence of bedrock contamination by leachate is indicated. But it is inferred that the weathered zones are contaminated in the landfill. In the block A and B, minor fault having the strike of N$70^{\circ}$W have been confirmed by dipole-dipole surveys, so future contamination of the bedrock by leachate is possible The degree of ground contamination is the highest in the D block due to the leachate plume mainly heading for this block. On the other hand, electrical soundings do not indicate ground contamination by leachate in the front area of the landfill.

• Journal of Families and Better Life
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• v.27 no.2
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• pp.29-43
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• 2009

This study proposes to implement premarital education programs designed to enhance potential capacity in marital life, targeted at marriage expectant couple and verify the effectiveness of the programs. For this study, 8 marriage expectant couples residing in Seoul participated. For this study, advance and follow-up surveys were conducted. To be specific, the advanced surveys questions were posed regarding general features, the level of communication, conflict-resolution skills and the attitude toward the role of the gender and so forth of those persons polled. In follow-up surveys, questions were asked regarding the extent to which the participant was satisfied with the contents of the education and teaching process in each session of the programs, the attitude toward the role of the gender, the level of communication and conflict-resolution skills. The effectiveness of the program was verified based on the subjective level of satisfaction of the instructor and the program manager and the statistical analyses of advance and follow-up surveys. Our findings show: First, the changes in 'the attitude toward the role of the gender' of the participants after 'the education of the role of the gender' were not significantly related. Second, after 'the education of communication' was implemented, the capability of the participants to communicate proved to have improved. Third, the extent to which the participants were satisfied with the contents of the education scored higher than the average, the level of educational satisfaction with 'the skills of communication between the husband and wife' scoring the highest. Fourth, with respect to the level of overall satisfaction with the educational effects of the program, the level of satisfaction with improved relationship between each party of the couple turned out relatively high, and the level of the overall education program also proved to be high.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.54-54
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• 2014

We use dense redshift surveys of nine galaxy clusters at z ~ 0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70-89%) and uniform completeness. With these dense redshift surveys, we construct galaxy number density maps using several galaxy subsamples. The shape of the main cluster concentration in the weak-lensing maps is similar to the global morphology of the number density maps based on cluster members alone, mainly dominated by red members. We cross correlate the galaxy number density maps with the weak-lensing maps. The cross correlation signal when we include foreground and background galaxies at 0.5zcl < z < 2 zcl is 10 - 23% larger than for cluster members alone at the cluster virial radius. The excess can be as high as 30% depending on the cluster. Cross correlating the galaxy number density and weak-lensing maps suggests that superimposed structures close to the cluster in redshift space contribute more significantly to the excess cross correlation signal than unrelated large-scale structure along the line of sight. Interestingly, the weak-lensing mass profiles are not well constrained for the clusters with the largest cross correlation signal excesses (>20% for A383, A689 and A750). The fractional excess in the cross correlation signal including foreground and background structures could be a useful proxy for assessing the reliability of weak-lensing cluster mass estimates.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.603-606
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• 2000

The cost needed for the construction and management of highways in the whole nation is rapidly growing so the research that can decrease the cost is required. However, most of the highway specs have simply converted from those of other countries, including USA. Therefore, some of our design and construction specs were not the optimum ones based on our own situation, requiring a research under the actual traffic and environment of our nation. The use of test road develops many aspects of highway engineering. Those are evaluation of construction materials, a general overview of korea pavement design and serviceability under the actual traffic and environmental condition of the nation. It is also economical and efficient compared to the trial construction of each item in spreaded form. A test road, 7.7km long with two lanes, is being constructed on the Inner Central Expressway. In this test road, 2.7km is planned for asphalt pavement and 3.4km is planned for concrete pavement. Three test bridges and five earth retaining structures will be included in the test road. Based on the master plan, the major performance was progressing such as detailed research modules of each area, preliminary research for the future research, sensor surveys for the behavior analyses of pavements and structures with installation methods and data acquisition systems, the foundation research of Integrated Instrumentation System and the Management Plan for automated measurement. Some area(structure research division, geotechnical research division) was designed the instrumentation plan because some instrument sensors must be installed during the construction of the test road. And then the instrumentation plan of each area was enforcing because a large majority of the instrument sensors must be installed after the construction of the test road. The field surveys with material property tests and pilot instrumentation test with sensor tests was also performing in accordance with the construction in the field.

• Nutrition Research and Practice
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• v.14 no.1
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• pp.62-69
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• 2020

BACKGROUND/OBJECTIVES: A number of studies examined secular trends in blood lipid profiles using time series data of national surveys whereas few studies investigated individual-level factors contributing to such trends. The present study aimed to examine secular trends in dietary and modifiable factors and hyper-LDL-cholesterolemia (HC) prevalence and evaluate their associations using time series data of nationwide surveys. SUBJECTS/METHODS: The study included 41,073 Korean adults aged ≥ 30 years from the 2005, 2007-2009, 2010-2012, 2013-2015, and 2016 Korea National Health and Nutrition Examination Surveys. Stepwise logistic regression analysis was performed to select significant factors associated with HC, which was defined as serum LDL cholesterol levels ≥130 mg/dL. RESULTS: The following factors showed a positive association with HC (P < 0.05): for men having higher body mass index (BMI), being married, having an office job, and consuming higher dairy and vegetable oil products; for women having higher age or BMI, having no job or a non-office job, not in a low-income household, and consuming higher dairy products. In the given model, the 2016 survey data showed that a 2 kg/㎡ reduction in BMI of obese persons resulted in a decreased HC prevalence from 30.8% to 29.3% among men and from 33.6% to 32.5% among women. CONCLUSIONS: Based on these findings, it is suggested that primary prevention programs should advocate having proper BMI for Korean adults with a high-risk of HC. However, whether discouraging consumption of dairy and vegetable oil products can reduce HC prevalence warrants further studies with a prospective longitudinal design.

• Korean System Dynamics Review
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• v.2 no.2
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• pp.119-134
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• 2001

Since 1998, government-led Korean venture business boom now proceeds into the stage of market-oriented venture business growth. At such a moment, this research is to clarify the relations between the success factors of Korean venture businesses, based on domestic and foreign documentary surveys and inquiry surveys over domestic venture businesses. This research starts from the necessity to overcome the limits of the existing researches by uni-dimensional probing research into success factors of Korean venture businesses and to manifest the multi-dimensional relations between the success factors from the various viewpoints. And this research adopts System-Dynamics methodology to manifest and utilize relations among those factors, avoiding the existing metrical approaches. This research can be called a new approach to the current ecosystems of Korean venture in which whether venture businesses success in Korea is considered to depend on the list on the stock market. For this, this research implemented verification analysis through the simulations of each factor at various levels to build causality map which clarifies the causality of success factors of venture businesses through the System-Dynamics methodology and to utilize it as a way of supporting tool for decision-making of venture businesses. This research will be able to suggest the reactions depending on various internal and external situations. This research tried to manifest the causality map of each factor on the basis of inquiry surveys and documentary surveys to verify feedback among each factor by the SD methodology. This research will be a basis bolster up the still fragile substructure of venture businesses through an efficient analysis framework using the verification of SD methodology and resulting outcomes from this research.