• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.240-247
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• 2012

Marginal and internal fit is an important part of the longevity of dental restorations. The purpose of this study was to analysis the marginal and internal fit of zirconia core by dental CAD/CAM system using innovative and non-destructive methods such as optical coherence tomography(OCT) and compare with conventional method such as silicone replica technique(SRT). Ten dental stone models of abutment of maxillary right central incisal were manufactured and scanned. Ten zirconia cores were fabricated with commercial CAD/CAM system. To measure the marginal and internal fit of each sample, five point of fitness were measured using 2 different methods(OCT and SRT). Statistical analysis was performed using independent sample t-test(${\alpha}$=0.05). OCT and SRT groups were not significantly different(P>0.05). By this results, analysis the fitness of dental restorations using OCT were acceptable measuring method.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.26 no.4
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• pp.123-149
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• 2015

As a mixture of both words 'Web' and 'Cartoon'. Webtoon is a sort of cartoons that come up with development of information technology. Web-toon is not just a cartoon but an OSMU for culture industries such as movies, dramas, games and more. While Web-toon's value is increasing, activities of securing and managing it as archives seem quite slow. To preserve web-toon as a web archives and digital contents which has long-term archival value effectively web archiving system should be required. This study analyzes webtoon's type and features. Also, requirements for web archiving system are extracted from case analysis of existing digital archives. With the results, this study proposes a method to design and implement web-toon archives based on OAIS reference model.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.80-86
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• 2014

In this study, we the estimated surface normalized difference vegetation index by using the KOrea Multi-Purpose SATellite-3 (KOMPSAT-3) multi-spectral images for comparative analysis. The estimated NDVI from KOMPSAT-3 is used as for comparison with the high resolution GeoEye products. The geometry conditions for atmospheric effects are selected from meta files of KOMPSAT-3 bundle data. The used geometry conditions are consist of solar zenith angle, solar azimuth angle, viewing zenith angle, viewing azimuth angle, and date. And, Atmospheric effects such as attenuation, scattering and absorption were physically simulated from water vapor, ozone and aerosol information. Generally, although ground measurements are important for accurate information, in this study, MODIS atmospheric products are used as atmospheric constituents. The surface reflectance from radiative transfer model is utilized for estimating vegetation index. The present study, to reduce atmospheric and geometry conditions between KOMPSAT-3 and GeoEye having difference observation characteristics, data acquisition time is carefully determined for reliable vegetation spectral characteristics.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.127-134
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• 2005

Design and construction of long-span bridge are recently increasing by development of computer technology. Specially, cable stayed bridge and suspension bridge having cable component are representative of long-span bridge may do. Therefore, this paper a present a methodology for cable tension force monitoring in cable-stayed bridge under construction using acceleration data acquired by the vibration method. To improve accuracy construction, all stay cables are measured, according to 4-step construction stage and change of temperature.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.325-335
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• 2014

This study provides an overview of instruments for mobile contents start-up companies promotion that are currently available in Seoul. It includes a brief description of several different types of start-up companies and development processes for each of those companies so that it can analyze and figure out critical success factors for sustainable growth. In addition, the case studies of five mobile contents related companies are used to obtain more detailed insights into the development processes. The study focuses on mobile contents startups promotion used as a public policy for encouraging more productive and knowledge-intensive ventures, with the aim of upgrading management activities and creating more startups-friendly business environment. Consequently, the key target groups of the measures discussed in the study include mobile contents start-ups and start-ups that exploit new business opportunities in Seoul.

• Journal of Korea Water Resources Association
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• v.45 no.4
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• pp.419-430
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• 2012

Due to the calculation difficulty on the hydraulic and hydrologic analysis for road drainage facilities design, these analysis techniques are not applicable. This study's result are development of minutely rainfall-intensity equation suitable for road drainage area, verification of rainfall-runoff model joining kinematic wave theory for road drainage area, computational model based GUI for road surface drainage facilities spacing and culvert's size decision and various road drainage channel design. Applicable test on the developed model is proceed, result that in case of road surface dranage facilities spacing is narrower 6~65% than present spacing calculation method, in other case of road cross dranage facilities size is bigger 6~140% than present size decision method.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.15-22
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• 2020

In this study, we propose an improvement method that can create U-Net model which detect fine concrete cracks by applying a weighted loss function. Because cracks in concrete are a factor that threatens safety, it is important to periodically check the condition and take prompt initial measures. However, currently, the visual inspection is mainly used in which the inspector directly inspects and evaluates with naked eyes. This has limitations not only in terms of accuracy, but also in terms of cost, time and safety. Accordingly, technologies using deep learning is being researched so that minute cracks generated in concrete structures can be detected quickly and accurately. As a result of attempting crack detection using U-Net in this study, it was confirmed that it could not detect minute cracks. Accordingly, as a result of verifying the performance of the model trained by applying the suggested weighted loss function, a highly reliable value (Accuracy) of 99% or higher and a harmonic average (F1_Score) of 89% to 92% was derived. The performance of the learning improvement plan was verified through the results of accurately and clearly detecting cracks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.78-84
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• 2006

This paper proposes a method to endow the mobility to the Zigbee protocol which is a short distance wireless communication technology among the standards of wireless sensor networks. The Zigbee has a low price, long life battery, simple structure and connectivity. So it is a suitable standard for the short distance wireless communication of $10m{\sim}70m$. As the Zigbee does not support the mobility, additional factors should be studied to deal adeptly with the diverse change in the real field. By solving the problem that the previous connection and binding table of the Zigbee end device should be reset due to the Zigbee end device address variation when the Zigbee end device moves from the present router to another router, this paper presents the method to communicate without data loss or disconnection.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.165-172
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• 2014

When a vehicle is running on the road, the surface conditions and environment of road by reason of insufficient road design standards is so greatly that have an effect on drivers. In particular, the road design of the past is conducted empirical and ideal judgment, but recently, the new technical development is attempted that three and four dimensional parameters is reconsidering and adjusting at the same time. In this study, we analyzed the vehicle behavior characteristics according to the change of driving speed and vertical grades on braking at the peak point of the frozen road by using a PC-crash program for traffic accident reconstruction. As a result, we were conformed the fact that the friction coefficient of road surface and the vehicle speed is affected by vehicle behavior characteristics for intersection vertical grades and were showed the feasibility of verification through a simulation in order to solve the problem of road design in advance.

• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.35-41
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• 2016

Geothermal heat pump (GHP) systems have been proved to be one of the most efficient systems for heating and cooling in buildings. However, an optimal energy performance depends on a good control of the system components, including heat pumps and circulation pumps, which affect to the total energy consumption of system. This paper presents the simulation results of the heat pump performance for two different control schemes, i.e. constant setting temperature (Control-A) and variable setting temperatures (Control-B) in buffer tank. A dynamic simulation tool, TRNSYS 17, was used to model the entire system and to assess the performance of the system. Simulation results show that the Control-B, which controls the temperature in buffer tank with outdoor air temperature, is a effective way to reduce the energy consumptions in heat pump (7.7%) and circulation pump (7.5%).