• Geophysics and Geophysical Exploration
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• v.19 no.1
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• pp.11-19
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• 2016

Two representative residual static methods of traveltime decomposition and stack-power maximization are discussed in terms of application to land seismic data. For the model data with synthetic shot/receiver statics (time shift) applied and random noises added, continuities of reflection event are much improved by stack-power maximization method, resulting the derived time-shifts approximately equal to the synthetic statics. Optimal parameters (maximum allowable shift, correlation window, iteration number) for residual statics are effectively chosen with diagnostic displays of CSP (common shot point) stack and CRP (common receiver point) stack as well as CMP gather. In addition to removal of long-wavelength time shift by refraction statics, prior to residual statics, processing steps of f-k filter, predictive deconvolution and time variant spectral whitening are employed to attenuate noises and thereby to minimize the error during the correlation process. The reflectors including horizontal layer of reservoir are more clearly shown in the variable-density section through repicking the velocities after residual statics and inverse NMO correction.

• The Journal of Korean Medicine
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• v.32 no.2
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• pp.92-101
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• 2011

Purpose: To evaluate the effects on vision care program including traditional Korean treatment for elementary school students. Methods: 172 eyes of eighty-six older elementary students underwent a vision care program, including traditional Korean treatment, for 3 months between March 2010 and June 2010. The vision care program included health education, such as lifestyle modification, vision strengthening exercises and a course of treatment with traditional Korean methods. Traditional Korean treatment covered periocular acupuncture point stimulation, periauricular acupuncture point stimulation and herbal drug therapy. All patients were examined for visual acuity and auto-refraction and filled out a satisfactory questionnaire about ocular discomforts and quality of life before and after treatments. Results: Patients with mild myopia (-0.75~-2.00) were 61 (35.5%), and 46 (26.7%) were emetropia (${\pm}0.50$ or less). After treatment, uncorrected visual acuity in both eyes was $0.77{\pm}0.46$, which was lower than that before treatment ($0.82{\pm}0.51$), but corrected visual acuity was $0.98{\pm}0.21$, which was higher than that before treatment ($0.93{\pm}0.28 $). About the refractive change, the emetropia group showed a slightly myopic shift while the mild myopia group intended to reduce the myopic error. However, this was not statistically significant. The scales of eyeball pain or discomfort decreased significantly from $17.59{\pm}22.5$ before treatment to $10.28{\pm}17.80$ after treatment, and the scales of the quality of life increased from $1.85{\pm}1.25$ before treatment to $2.25{\pm}1.30$ after treatment. Most patients (90.7%) were satisfied with their treatment results. Conclusions: The vision care program including traditional Korean treatment for elementary school students was effective to improve corrected visual acuity in both eyes and delay the progression of school myopia. In addition, it helped to reduce eyeball pain and discomfort and ultimately to enhance quality of life. Long-term follow-up studies will be needed.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.1
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• pp.36-44
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• 2019

$21^{st}$ century is digitally civilized era. Technologies such as AI, Iot, Big Data, Mobile and etc makes this era digitally advanced. These advancement of the technology greatly impacted detection range of the radar. Human's eye sight can see about 20Km and hear 20 ~ 20000 Hz. These limitations can be overcome using radar. This radar technology is used in military, aircraft, ship, vehicle and etc. to replace human eye. However, radar technology is capable of making False Alarm Rate. This document will propose the fix of these problems. Radar's distortion includes beam refraction, diffraction and reflection. These inaccurate data result in deterioration of human judgements and my cause various casualties and damages. Radar goes through annual testing to test how many false alarm is being produced. Normal radar usually makes 10 to 20 False alarms. In emergency situation, if operator were to follow this false alarm, this might result in following false object or take 12 more seconds to follow the right object. This problem can be overcome by using different radar data from different places and angles. This helps reduces False Alarm rate and track the object twice as fast.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.603-614
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• 2021

Recently, the surface temperature in the seas around Korea has been continuously rising. This temperature rise causes changes in fishery resources and affects leisure activities such as fishing. In particular, high temperatures lead to the occurrence of red tides, causing severe damage to ocean industries such as aquaculture. Meanwhile, changes in sea temperature are closely related to military operation to detect submarines. This is because the degree of diffraction, refraction, or reflection of sound waves used to detect submarines varies depending on the ocean mixed layer. Currently, research on the prediction of changes in sea water temperature is being actively conducted. However, existing research is focused on predicting only the surface temperature of the ocean, so it is difficult to identify fishery resources according to depth and apply them to military operations such as submarine detection. Therefore, in this study, we predicted the temperature of the ocean mixed layer at a depth of 38m by using temperature data for each water depth in the upper mixed layer and meteorological data such as temperature, atmospheric pressure, and sunlight that are related to the surface temperature. The data used are meteorological data and sea temperature data by water depth observed from 2016 to 2020 at the IEODO Ocean Research Station. In order to increase the accuracy and efficiency of prediction, LSTM (Long Short-Term Memory), which is known to be suitable for time series data among deep learning techniques, was used. As a result of the experiment, in the daily prediction, the RMSE (Root Mean Square Error) of the model using temperature, atmospheric pressure, and sunlight data together was 0.473. On the other hand, the RMSE of the model using only the surface temperature was 0.631. These results confirm that the model using meteorological data together shows better performance in predicting the temperature of the upper ocean mixed layer.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.431-437
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• 2004

This research reviewed the objects of 384 persons (male:86, female:298) from 6 to 50 years old visited the S. Optical shop at Mokpo over two times from Mar. 2002 to Feb. 2004. We obtained the following results by analyzing the visual acuity prescription to keeping at S. Optical shop. 1. The abnormal refraction eyes were 191 persons(49.74%) for simple myopia, 2 persons(0.52%) for myopic simple astigmatism, 180 persons(46.88%) for myopic compound astigmatism, and 1 person(0.26%) for simple hyperopia, 2 persons(0.52%) for hyperopic simple astigmatism, 8 persons(2.08%) for hyperopic compound astigmatism, respectively. 2. Classifying of correction power for 373 persons (male:84, female:289) myopia, so that showed 166 persons(male:36, female) between $$0.25D{\leq_-}2.00D$$, 194 persons(male:46, female:148) between $$2.25D{\leq_-}6.00D$$, 13 persons(male:2, female:11) for over 6.250 respectively. 3. According to the kinds of 192 persons astigmatism subjects(male:53, female:148), direct astigmatism was 145 persons(male:32, female:113), oblique astigmatism 33 persons (male:12, female:21), reverse astigmatism 14 persons(male:5, female:9). 4. The variation of spherical power for myopia showed 299 persons(male:71, female:228) between $$0.00D{\leq_-}0.50D$$, 64 persons(male:11, female:53) between $$0.51D{\leq_-}1.00D$$, 9 persons(male:2, female:7) between $$1.01D{\leq_-}1.50D$$, 1 person(male:0, female:1) between $$1.51D{\leq_-}2.00D$$ variation respectively. Hyperopia showed 8 persons(male:1, female:7) between $$0.00D{\leq_-}0.50D$$, 3 persons(male:1, female:2) between $$0.51D{\leq_-}1.00D$$ variation respectively. 5. The variation of astigmatism power showed 181 persons(male:48 female:113) between $$0.00D{\leq_-}0.25D$$, 25 persons(male:9, female:16) between $$0.26D{\leq_-}0.50D$$, 6 persons(male:0, female:6) between $$0.51D{\leq_-}0.75D$$ astigmatism variation respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.143-148
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• 2013

Purpose: The aim of this study was to investigate the distribution of age and gender, types of intraocular lens (IOL), and refractive errors in subjects who had cataract surgery. Methods: 2,217 subjects who had cataract surgery were surveyed at an optometry clinic in Chungbuk from 2010 to 2012. Information about IOL was obtained from case history, reflective and retroillumination images IOL by auto refracto-keratometer. Refractive errors were determined by objective and subjective refraction. Results: The mean age of the subjects was $71.74{\pm}10.62$ years. The number of cataract surgeries increased from 524 persons in 2010 to 888 persons in 2012. Of the subjects surveyed, 52 persons (2.3%) were under the 40 years of age, 144 persons (6.5%) were in 50s, 404 persons (18.2%) were in 60s, 1,132 persons (51.1%) were in 70s, 485 persons (21.9%) were in above 80s. Cataract surgery was significantly prevalent in more female (1,338 persons, 60.4%) than in male (879 persons, 39.6%). Types of IOL were 2,141 persons (96.6%) for monofocal lens, special IOLs such as multifocal, accommodative and toric lens were 76 persons (3.4%). The distribution of refractive errors after cataract operation were 1,588 eyes (38.5%) for simple myopic astigmatism, 327 eyes (7.9%) for simple hyperopic astigmatism, 601 eyes (14.6%) for mixed astigmatism, 1,240 eyes (30.0%) for myopia, 136 eyes (3.3%) for hyperopia, and 234 eyes (5.7%) for emmetropia. The uncorrected and best corrected visual acuity of the subjects were $0.55{\pm}0.25$ and $0.80{\pm}0.23$, respectively. Conclusions: The prevalence of cataract surgery increased with age until 70s years of age, it was more prevalent in men than women over 60s, and frequency of special types of IOL were low. Most cataract surgeries left residual refractive errors. Therefore even after cataract surgery it may need spectacles for better vision at either distance or near.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.107-116
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• 2000

This study is of investigation of refraction error, spectacles and contact lenses wearing state, visual acuity test, ophthalmologic common sense and vision care, using questionnaire study for 850 male and female high school students in Kunsan and Chongup City, Cheolla North Province. The results are as follows: 1. Among the 823 answerers, emmetropia is 18%, myopia is 55.1%, and hyperopia is 7%, respectively. 2. Among the 837 answerers, 381 students(45.5%) wear spectacles or contact lenses. Among the 381 students who wear spectacles or contact lenses, 78% wear only spectacles, 4% wear only contact lenses and 18% wears spectacles sometimes or contact lenses sometimes. 3. The places where the answerers had visual acuity test to wear spectacles or contact lenses are optical shop(64.7%), hospital(28.3%), unchecked(4.2%) and the others(2.7%). The places where the answerers had visual acuity test to change their spectacles or contact lenses are optical shop(82%), hospital(28.3%), unchecked(6.6%) and the others(1.9%). 4. As for the period of visual acuity test, from 6 months to one year is 54.1%, within 6 months is 9.2%, from one year to two years is 29.5%, and more than two years is 7.2%. 5. The contact lens wearers purchased their contact lenses at optical shops(94%) and at hospital(6%). 6. The reasons why they like wearing contact lenses are their appearance(51.2%), convenience in physical excercise(23.l%), lighter weight than spectacles(9.8%) and the others(15.7%). 7. As for the spectacles frame they like, plastic frame is 24.4%, gold or silver plated frame is 43.4%, coloured frame is 32.1%. 8. As for the considerations in choosing spectacles frame, their design is 37%, their quality is 36%, their price is 14.7% and their brand is 12.5%. 9. As for the period for changing spectacles, 10.5% is within 6 months, 57.3% is 6months to 1 year, 22.4% is 1 year to 2 months and 9.6% is more than 2 years. 10. There is a false fact, in Korea, that even though one has his poor eyesight, not wearing custom is helpful for the eyesight recovery. As for their conviction of the false fact, 10.5% of the answerers have 100% conviction, 22.5% of them have 22.5% conviction, 49.5% of them have 50% conviction and 17.5% of them don't have any conviction. 11. 48.5% of the answerers are interested in their vision care while 51.5% of them are not interested at all. As for the way of vision care, the vision-care way to keep enough distant when they are watching TV, when they are using computers and when they are reading, is 49% while the vision-care way such as hypogastric breathing or eye massage is 11%. And alimentotherapy is 4% and the rest who are not interested in vision care is 36%. 12. When they come to an age, the students who want vision correction operation are 45.9% while the students who do not want it are 27%. The students who do not have any idea about the operation are 27.1%

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.26-33
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• 2008

The analysis of wide-angle seismic reflection and refraction data plays an important role in lithospheric-scale crustal structure study. However, it is extremely difficult to develop an appropriate velocity structure model directly from the observed data, and we have to improve the structure model step by step, because the crustal structure analysis is an intrinsically non-linear problem. There are several subjective processes in wide-angle crustal structure modelling, such as phase identification and trial-and-error forward modelling. Because these subjective processes in wide-angle data analysis reduce the uniqueness and credibility of the resultant models, it is important to reduce subjectivity in the analysis procedure. From this point of view, we describe two software tools, PASTEUP and MODELING, to be used for developing crustal structure models. PASTEUP is an interactive application that facilitates the plotting of record sections, analysis of wide-angle seismic data, and picking of phases. PASTEUP is equipped with various filters and analysis functions to enhance signal-to-noise ratio and to help phase identification. MODELING is an interactive application for editing velocity models, and ray-tracing. Synthetic traveltimes computed by the MODELING application can be directly compared with the observed waveforms in the PASTEUP application. This reduces subjectivity in crustal structure modelling because traveltime picking, which is one of the most subjective process in the crustal structure analysis, is not required. MODELING can convert an editable layered structure model into two-way traveltimes which can be compared with time-sections of Multi Channel Seismic (MCS) reflection data. Direct comparison between the structure model of wide-angle data with the reflection data will give the model more credibility. In addition, both PASTEUP and MODELING are efficient tools for handling a large dataset. These software tools help us develop more plausible lithospheric-scale structure models using wide-angle seismic data.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.579-588
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• 2018

Purpose : To analyze the eyeglasses supply system for ametropic soldiers in ROK military. Methods : We investigated and analyzed the supply system of eyeglasses for the ametropic soldiers provided by the Korean military. The refractive powers and corrected visual acuity were measured for 37 ametropic soldiers who wear insert glasses for ballistic protective and gas-masks supplied by the military based on their habitual prescriptions. Full correction of refractive error was prescribed for subjects having less than 1.0 of distance visual acuity, and comparison was held for inspecting the changes in corrected visual acuity. Suggestions were provided for solving the issues regarding current supplying system, and this study investigated the applicabilities for utilizing professional optometric manpower. Results : The new glasses supplied by army for ametropic soldiers were duplicated from the glasses they worn when entering the army. The spherical equivalent refractive powers of the conventional, ballistic protective and gas-mask insert glasses supplied for 37 ametropic soldiers were $-3.47{\pm}1.69D$, $-3.52{\pm}1.66D$ and $-3.55{\pm}1.63D$, respectively, and the spherical equivalent refractive power of full corrected glasses was $-3.79{\pm}1.66D$, which showed a significant difference(p<0.05). The distant corrected visual acuity measured at high and low contrast(logMAR) of conventional, ballistic protective and gas-mask insert glasses were $0.06{\pm}0.80$, $0.21{\pm}0.82$, $0.15{\pm}0.74$, $0.34{\pm}0.89$, $0.10{\pm}0.70$ and $0.22{\pm}0.27$, respectively, while the corrected visual acuity by full corrected glasses were increased to $0.02{\pm}1.05$, $0.10{\pm}0.07$, $0.09{\pm}0.92$, $0.26{\pm}0.10$, $0.04{\pm}1.00$ and $0.19{\pm}1.00$, respectively. There was a significant difference(p<0.05) except for the case of the low contrast corrected visual acuity of the conventional and gas-mask insert glasses. The procedure for ordering, dispensing, and supplying military glasses consists of 5 steps, and it was found that approximately two weeks or more are required to supply from the initial examination. Conclusion : The procedure of supplying the military glasses showed three issues: 1) a lack of refraction for prescription system, 2) relatively long length of time required for supplying the glasses, 3) an inaccurate power of supplied glasses. In order to solve those issues, in the short term, education is necessarily required for soldiers on the measurement of the refractive powers, and in the near future, further standard procedures for prescription of glasses as well as the securement of optometric manpower are expected.