• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.249-259
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• 2008

The present paper studies the effect of the slope gradient of a fully permeable submerged breakwater using a newly developed numerical model that is able to consider the flow through a porous midium with inertial, laminar and turbulent resistance terms, i.e. simulate directly WAve-Structure (submerged breakwater)-Sand seabed interaction and can determine the eddy viscosity with LES turbulence model in 2-Dimensional wave field (LES-WASS-2D). The developed model was validated through the comparison with an existing experimental data, and further used for various numerical experiments in oder to investigate the complicated hydrodynamics on the varying slope gradient of permeable submerged breakwater. We found an acceptable phenomenon, as we expect intuitively, that reflection and transmission coefficients decrease simultaneously as slope gradient decrease. In addition, the breaking point, the circulation flow and mean vorticity around a submerged breakwater are throughly discussed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.279-291
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• 2023

In recent years, language model-based generative AI technologies have made remarkable progress. In particular, it has attracted a lot of attention due to its increasing potential in various fields such as summarization and code writing. As a reflection of this interest, the number of patent applications related to generative AI has been increasing rapidly. In order to understand these trends and develop strategies accordingly, future forecasting is key. Predictions can be used to better understand the future trends in the field of technology and develop more effective strategies. In this paper, we analyzed patents filed to date to identify the direction of development of language model-based generative AI. In particular, we took an in-depth look at research and invention activities in each country, focusing on application trends by year and detailed technology. Through this analysis, we tried to understand the detailed technologies contained in the core patents and predict the future development trends of generative AI.

• Information Systems Review
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• v.22 no.1
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• pp.73-89
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• 2020

This study started to identify the "Forward-looking" of the technology appraisal model introduced to diversify financing methods of SMEs and improve financial accessibility. The multivariate regression analysis was performed by setting the business performance(growth, profitability, and stability) of technology financing companies as dependent variables, technology appraisal items as independent variables, number of employees, age of the company, asset and the Korea Standard of Industry Classification related to firm size and industry characteristics as control variables. As a result of the analysis, the technology appraisal items did not explain the profitability of the company significantly and had a limited explanatory power on growth potential. However, in terms of stability, we confirmed that R&D capacity is a significant variable explaining the debt ratio of technology financing companies. Therefore, it is concluded that the 'Forward-looking' reflection on the growth and profitability of the company should be strengthened in the future adjustment of the technology appraisal model and the development of the technology appraisal model for investment.

• Ocean and Polar Research
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• v.30 no.4
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• pp.453-466
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• 2008

In order to examine the generation mechanism of long ocean waves along the west coast of Korea and to understand the amplification process of the long ocean waves, sea level, atmospheric pressure and wind data observed every minute from 2007 March 29 to 2007 April 1 were analyzed and onedimensional numerical ocean model experiments were performed. An atmospheric pressure jump propagated southeastward from Backryungdo to Yeonggwang along the west coast of Korea with speed of $13{\sim}27\;m/s$ between 2007 March 30 23:00 and 2007 April 1 1:30. Average magnitude of pressure jump was 4.2 hPa. As a moving atmospheric jump propagated from north to south along the coast, long ocean waves were generated and the sea level abnormally rose or fell at Anheung, Kunsan, Wido and Yeonggwang. Average amplitude of sea level rise (or fall) was about 113.6 cm. In a one-dimensional numerical ocean model, nonlinear shallow water equations were numerically integrated and a moving atmospheric pressure jump with traveling speed of 24 m/s was used as an external force. While the atmospheric pressure jump travels over 60 m depth ocean, a long ocean wave is generated. Because the propagation speed of the atmospheric jump is almost equal to that of the long ocean wave, Proudman resonance occurs and the long ocean wave amplifies. As the atmospheric pressure jump moves into the coastal area shallower than 60 m, the speed of the long ocean wave decreases and Proudman resonance effect decreases. However, the amplitude of the long ocean wave increases and wave length becomes shorter because of shoaling effect. When the long ocean wave hits the land boundary, amplitude of the long ocean wave drastically amplifies due to reflection. Data analysis and numerical experiments suggest that the southeastward propagation of an atmospheric pressure jump over the shallow ocean, which is a necessary condition for Proudaman resonance, generated the long ocean waves along the west coast of Korea on 2007 March 31 and the ocean waves amplified due to shoaling effect in the coastal area and reflection at the shore.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.163-175
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• 2017

In land seismic exploration, irregular surface topography and weathering layer in near surface distorts the reflected signals of data. Therefore, typical land seismic data should be compensated for this distortion by static correction. To perform the static correction, near-surface velocity is required, which can be obtained by seismic refraction survey. However, land seismic data is often acquired in a limited form of geometry depending on the equipment availability, accessibility condition, and permission for the survey site. In this situation, refraction analysis should be performed using reflection data because it is impossible to acquire refraction-oriented data due to limited source and receiver geometry. In this study, we aimed to analyze the reliability of the results obtained by refraction traveltime tomography when using reflection data with a limited number of sources and receivers from irregular surface topography. By comparing the inversion result from irregular topography with that from flat surface, we found that the surface topography affects the reliability of the inversion results to some degree. We also found that the number of sources has little effect on the inversion results unless the number of sources are very small. On the other hand, we observed that velocity distortion occurred in the overlapped part of receiver arrays when using a limited number of receivers, and therefore suggested the size of the least overlapping ratio to avoid the velocity distortion. Finally, we performed numerical tests for the model which simulates the surface topography and acquisition geometry of the survey region and verified the reliability analysis of inversion results. We identified reliable areas and suspicious area of the inverted velocity model by applying the analysis results to field data.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.105-113
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• 2009

The interpretation of observed waveform characteristics identified in refraction and wide-angle reflection data increases confidence in the crustal structure model obtained. When calculating traveltimes and raypaths, wavefront methods on a regular grid based on graph theory are robust even with complicated structures, but basically compute only first arrivals. In this paper, we develop new algorithms to compute traveltimes and raypaths not only for first arrivals, but also for fast and later reflection arrivals, later refraction arrivals, and converted waves between P and S, using the modified wavefront method based on slowness network nodes mapped on a multi-layer model. Using the new algorithm, we can interpret reflected arrivals, Pg-later arrivals, strong arrivals appearing behind Pn, triplicated Moho reflected arrivals (PmP) to obtain the shape of the Moho, and phases involving conversion between P and S. Using two models of an ocean-continent transition zone and an oceanic ridge or seamount, we show the usefulness of this algorithm, which is confirmed by synthetic seismograms using the 2D Finite Difference Method (2D-FDM). Characteristics of arrivals and raypaths of the two models differ from each other in that using only first-arrival traveltime data for crustal structure analysis involves risk of erroneous interpretation in the ocean-continent transition zone, or the region around a ridge or seamount.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.199-207
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• 2009

The objective of this study was to evaluate the effect of color measuring instrument by measuring the color of dental composite resins. Nine shade light cured composite resin disks were prepared (diameter : 15 mm, thickness : 4 mm). CIE $L^*a^*b^*$ color scale of each disk was measured with 3 different types of spectrophotometer [MiniScan XE plus (Model 4000S, Hunter Lab, USA), CM-3500d (Minolta, Japan) and Specbos 2100 Miniature VIS Reflection spectrometer (Serial No: 319416, JETI Technishe VIS Instrumentic GmbH. Germany)]. Miniscan XE Plus and CM-3500d using identical measuring geometry with different size of viewing aperture. But Specbos 2100 using different measuring geometry. Within the limitation of this study, there were color difference (${\Delta}E^*$) from 2.4 to 7.8 between Miniscan XE Plus and CM-3500d, but $L^*$, $a^*$, $b^*$ values showed the high correlation. However, there were great color difference (${\Delta}E^*$) in the extent of about 20 between instruments with the different measuring geometry. Therefore, color scale measured by color measuring instrument should be used as a relative value rather than an absolute value in the field of dentistry.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.401-415
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• 2020

The purpose of this study was to investigate the factors that affect the maintenance of the effect of mentoring for beginning science teachers. Mentee teachers for this study were ten mentee teachers who took part in the collaborative mentoring from 2014 to 2018. For this study, the videos of the first and fifth classes submitted during the mentoring program, mentors and mentees' journals, the videos of the classes recorded in 2019, questionnaires about reflection on the mentoring program, and interview materials were collected and analyzed. The result of this study is as follows. First, the reflective thinking was sustained after the mentoring program, and this played a crucial role in maintaining the effects of the mentoring. The group that showed the improvement of RTOP score had reflective thinking and made reflective practice on their teaching. Most participants in the group created the classes of constructivism based on self-reflection on their classes. However, no positive changes in the classes occurred to mentee teachers who couldn't have reflective thinking. Second, reflective practices during the mentoring program exerted a strong influence on the teaching method of mentee teachers. The group of the improvement in RTOP score strived to apply student-centered model of instruction to their classes. It was showed that most mentee teachers in the group kept applying the student-centered model to their classes after the mentoring was completed. These results indicate reflective thinking and reflective practice are crucial factors to the effect of the mentoring and its maintenance.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.223-228
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• 2010

High-frequency bottom loss measurements for grazing angle of $82^{\circ}$ in frequency range 17-40 kHz were made in Jinhae bay in the southern part of Korea. Observations of bottom loss showed the strong variation as a function of frequency, which were compared to the predicted values using two-layered sediment reflection model. The geoacoustic parameters including sound speed, density and attenuation coefficient for the second sediment layer were predicted from the empirical relations with the mean grain size obtained from sediment core analysis. The geoacoustic parameters for the surficial sediment layer were inverted using Monte Carlo inversion algorithm. A sensitivity study for the geoacoustic parameters showed that the thickness of surficial sediment layer was most sensitive to the variation of the bottom loss.

• Korean Journal of Construction Engineering and Management
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• v.10 no.4
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• pp.3-13
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• 2009

When promoting BTL(Build Transfer Lease; below BTL) project, negotiation is a stage of examining observation and reflection of RFP(Request for Proposal below RFP) in terms with facilities, operating and financing. It keeps an important position in whole process. However, there is no consistent guideline or model which helps evaluating the result of negotiation. It is difficult to apprise the quantitative outcome after executing negotiation. Thus, this study presented the Value Engineering -based process and model of estimating the outcome of negotiation for the purpose of estimating and verifying the result of negotiation objectively, Evaluating factors of negotiation were classified into 6 fields, 38 divisions and 135 items, focused on cultural facilities on BTL project. Weight of every factor was estimated, and quantitative checklist was established. This study presented the model which could measure the outcome of negotiation. This result would be a critical checklist before negotiation on BTL project, an index of feedback during negotiation, and also a standard of estimating the outcome after negotiation.