• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.25-36
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• 2007

We researched the change of astigmatism power when the fixation point moved from far distance to near distance. Astigmatism power was measured by using both eyes open-view auto-refractometer. We divided the ages between 5 and 67 years old into 12 groups with 1,598 healthy eyes(male-698 eyes and female-900 eyes) without eyes problems and experiences of eyes operations. The mean power in far astigmatism showed that with-the-rule of the total astigmatism: -0.79D, with-the-rule of the corneal astigmatism: -1.07D and against-the-rule of the residual astigmatism : -0.79D were found most respectively. The correlation between cornea astigmatism and total astigmatism was y=0.7493 x + 0.5661 r=0.6510, residual astigmatism and total astigmatism was y=0.248 x - 0.5926 r=0.2598 and corneal astigmatism and residual astigmatism was y=-0.4439 x - 0.1813 r=-0.5551 in the far distance. The mean power in near astigmatism showed that with-the-rule of total astigmatism : -0.92D, with-the-rule of corneal astigmatism : -1.12D, against-the-rule of residual astigmatism : -0.87D were found most respectively. In the near distance, The correlation between corneal astigmatism and total astigmatism was y=0.6872 x + 0.5934 r=0.6204, residual astigmatism and total astigmatism was y=0.303 x - 0.6066 r=0.3165, corneal astigmatism and residual astigmatism was y=-0.46 x - 0.0626 r=-0.5322. When the fixation point moved far distance to near distance, the differences of power according to the type of astigmatism were total astigmatism: $-0.07D{\pm}0.44D$, corneal astigmatism: $-0.04D{\pm}0.54D$ residual astigmatism:$0.01D{\pm}0.53D$. Most of astigmatism refractive power was increased except for oblique-the -astigmatism. When the fixation point moved far distance to near distance, the change of astigmatism refractive power showed total astigmatism: 540 eyes(33.7%), corneal astigmatism: 638 eyes(39.9%), residual: 841 eyes(52.6%).

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.259-264
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• 2016

Purpose: To establish the cause of decrease in body stability and to analyze the effects on sensory organs maintaining static balance according to the induced astigmatic blur. Methods: Twenty subjects (10 males, 10 females; mean age, $23.40{\pm}2.70years$) were participated in this study. To induce myopic simple astigmatism, the axis directions of cylindrical lenses were placed $180^{\circ}$ on both eyes (with-the-rule), $90^{\circ}$ on both eyes (against-the-rule), and $45^{\circ}$ on both eyes (oblique). Cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.00, +4.00, and +5.00 D were used to increase astigmatic blur in each astigmatism types. General stability (ST) and sway power (SP) in frequencies by each sensory organs were analyzed using the TETRAX biofeedback system. Results: ST in the all astigmatism types were raised with increase of astigmatic blur compared to full corrected condition, but a significant difference only showed in the induced oblique astigmatism. According to the results of correlation analysis between ST and SP in the each frequencies with increase of astigmatic blur, the causes of increased ST in the induced oblique astigmatism showed to have a high correlation in order of somatosensory system (high-medium frequency), central nervous system (high frequency), peripheral vestibular system (low-medium frequency), and visual system (low frequency). Conclusions: The visual information by uncorrected oblique astigmatism may disturb the normal functions of all sensory organs maintaining body balance, consequently, the body stability can be reduced. Therefore, optimal correction of astigmatism can play an important role for reducing the instability of body balance.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.227-233
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• 2016

Purpose: On this study, we compared the relationship of dynamic stereoacuity according to the dominant eye, degree of dominant eye, and dominant agreement eye and hand. Methods: For 130 adults (male 70, female 60), mean age of $21.06{\pm}2.21years$ old, dominant eye, degree of dominant eye were measured by objective examination by using the diameter $3.8cm{\times}3.8cm$ thin ring, the dynamic stereoacuity were measured by three-rods test (iNT, Korea). Results: Dynamic stereoacuity according to the dominant eye was center dominant eye without dominance was $14.97{\pm}13.80sec$ of arc, right eye $22.10{\pm}20.01sec$ of arc, left eye $22.31{\pm}20.39sec$ of arc. Dynamic stereoacuity was better when there was no dominance, but the correlation of the dominant eye with dynamic stereoacuity was very low. When Dynamic stereoacuity was separated by in the Center, Mild, Strong, dynamic stereoacuity was $14.97{\pm}13.80sec$ of arc, $20.76{\pm}15.73sec$ of arc and $24.45{\pm}25.60sec$ of arc respectively. The dynamic stereoacuity results were worse when dominance was stonger. However dynamic stereoacuity was better than Center when the degree of dominant eye was rather strong in the dominant left eye. Dynamic stereoacuity according to the dominant eye and hand showed that right eye and hand was $22.63{\pm}20.54sec$ of arc, left eye and hand was $17.36{\pm}10.13sec$ of arc, right eye and left hand was $14.79{\pm}7.05sec$ of arc, left eye and right hand was $22.97{\pm}21.42sec$ of arc so dynamic stereoacuity was comparatively good when the dominant hand was left. Conculsions: Correlation between the dynamic stereoacuity according to the dominant eye, degree of dominant eye was low, however when degree of dominant eye was Center 14.97 sec of arc, Strong 24.45 sec of arc, the dynamic stereoacuity tended to worse when degree of dominant eye was strong. As a result, dominant eye, degree of dominant eye would have to be considered in a more comfortable binocular balance between prescribed for the wearer in binocular vision correction in binocular function such stereoacuity, sports vision training, presbyopia correction and mono vision.

• Journal of National Security and Military Science
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• s.13
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• pp.137-658
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• 2016

1. Movement of the leaders of the Silla army The leaders of the Silla army traveled from Gyeongju(경주) to Icheon (이천), Deokjeokdo(덕적도) Island, and Hwangsanwon(황산원) during the period of the Against Baekje(백제) War that began in 660. Movement route between Gyeongju and Icheon : Gyeongju(경주)-Daegu(대구)-Gumi(구미)-Gimcheon(김천)-Chupungryeong(추풍령)-Geumdol Fortress(금돌성)-Boeun(보은)-Jincheon(진천)-Juksan(죽산)-Bubal-eup(부발읍) Movement route between Bubal-eup and Deokjeokdo Island : Bubal-eup(부발읍)-Ipo(이포) Ferry-Haengju(행주) Ferry-Palmido (팔미도) Island-Seonjaedo(선재도) Island-Yeongheungdo(영흥도) Island-Pido(피도) Island-Soyado(소야도) Island-Deokjeokdo(덕적도) Island Movement route between Deokjeokdo Island and Hwangsan: Deokjeokdo(덕적도) Island-Danghangpo(당항포)-Jincheon(진천)-Boeun (보은)-Okcheon(옥천)-Geumsan(금산)-Tanhyeon(탄현)-Hwangsan (황산)-Ganggyeong(강경)-Buyeo(부여) 2. Movement of the combat units of the Silla army Jincheon area : 4,325 persons of the Geupdang unit(急幢) and 611 persons of the Kaegeumdang unit(罽衿幢) were deployed. These units moved from Jincheon to Cheongju, Yeongi, and Gongju, and contained Ungjin Fortress(熊津城) (6,650 Baekje troops). Boeun area : 4,763 persons of the Daedang(大唐) unit, 3,548 persons of the Hajujeong unit(下州停), 3,017 persons of the Namcheonjeong unit(南川停), and 4,500 persons of the Saseoldang unit(四設幢) were deployed. These units moved from Boeun(보은) to Okcheon(옥천), Geumsan(금산), Tanhyeon,(탄현) and Hwangsan(황산). Geumdol Fortress area : 3,753 persons of the Sangjujeong unit(上州停), 5,762 persons of the Seodang unit(誓幢), 3,753 persons of the Guidang unit(貴幢), and 5,562 persons of the Nangdang uni(郎幢)t were deployed. These units moved from Geumdol Fortress to Hwanggan(황간), Yeongdong(영동), Geumsan(금산), Tanhyeon(탄현), and Hwangsan(황산). Jirye area: 3,017 persons of the Eumrihwajeong unit(音里火停) and 3,017 persons of the Ehwahyejeong unit(伊火兮停) were deployed. These units moved from Jirye(지례) to Juchiryeong(走峙嶺), Mupung (무풍), Muju-eup(무주읍), and Bunam-myeon(부남면) in Muju-gun. Goryeong area: 3,017 persons of the Samryanghwajeong unit(三良火停) and 3,017 persons of the Sosamjeong unit(召參停) were deployed. These units moved from Goryeong(고령) to Geochang(거창), Hamyang(함양), Namwon(남원), Sunchang(순창), and Jeongeup(정읍). 3. Movement of the Tang army Dangjin area(당진 방면) : 1,000 persons were deployed. These units moved from Dangjin(당진) to Myeoncheon(면천), Yesan(예산), and Imjon Fortress(임존성). Garijeo area(가리저 방면) : 1,000 persons were deployed in the Garijeo(加里渚) area. These units moved from Garijeo(가리저) to Myeoncheon(면천), Yesan(예산), and Imjon Fortress(임존성). Geumganggu area(금강구 방면) : 000 persons were deployed. These units moved from Geumganggu(금강구) to Ganggyeong(강경) and Sabi Fortress(사비성). 4. Baekje military deployment Total troops of the Baekje army : There were 60 thousand Baekje troops according to the Old Book of Tang(舊唐書). Troop deployment by the Baekje army: 62,230 persons were deployed in 15 regions: 1,000 in Dangjin(당진), 1,000 in Garijeo(가리저), 6,120 in Imjon Fortress(임존성), 1,120 in Namjam Fortress(남잠성), 1,350 in Dooryangyun Fortress(두량윤성), 870 in Wangheungsajam Fortress(왕흥사잠성), 6,650 in Ungjin Fortress(웅진성), 1,120 in Jinhyeon Fortress(진현성), 1,000 in Dooshiwonak(두시원악), 1,000 in Irye Fortress(이례성), 5,000 in Gosaburi Fortress(고사부리성), 5,000 in Gujiha Fortress(구지하성), 3,000 plus 3,000 in Gibeolpo and Yangan(기벌포 양안), 5,000 in Deukan Fortress(득안성), and 20,000 in Sabi Fortress(사비성).

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.216-225
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• 2011

Following the proliferation of three-dimensional video contents and displays, many terrestrial broadcasting companies have been preparing for stereoscopic 3DTV service. In terrestrial stereoscopic broadcast, it is a difficult task to code and transmit two video sequences while sustaining as high quality as 2DTV broadcast due to the limited bandwidth defined by the existing digital TV standards such as ATSC. Thus, a terrestrial 3DTV broadcasting with a heterogeneous video codec system, where the left image and right images are based on MPEG-2 and H.264/AVC, respectively, is considered in order to achieve both high quality broadcasting service and compatibility for the existing 2DTV viewers. Without significant change in the current terrestrial broadcasting systems, we propose a joint rate control scheme for stereoscopic 3DTV service based on the heterogeneous dual codec systems. The proposed joint rate control scheme applies to the MPEG-2 encoder a quadratic rate-quantization model which is adopted in the H.264/AVC. Then the controller is designed for the sum of the left and right bitstreams to meet the bandwidth requirement of broadcasting standards while the sum of image distortions is minimized by adjusting quantization parameter obtained from the proposed optimization scheme. Besides, we consider a condition on maintaining quality difference between the left and right images around a desired level in the optimization in order to mitigate negative effects on human visual system. Experimental results demonstrate that the proposed bit rate control scheme outperforms the rate control method where each video coding standard uses its own bit rate control algorithm independently in terms of the increase in PSNR by 2.02%, the decrease in the average absolute quality difference by 77.6% and the reduction in the variance of the quality difference by 74.38%.

• Journal of Wetlands Research
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• v.22 no.3
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• pp.194-199
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• 2020

Unlike in the past, the world is facing water shortages due to climate change and difficulties in simultaneously managing the risks of flooding. The Four Major Rivers project was carried out with the aim of realizing a powerful nation of water by managing water resources and fostering the water industry, and the construction period was relatively short compared to the unprecedented scale. Therefore, the prediction and analysis of how the river environment changes after the Four Major Rivers Project is insufficient. Currently, part of the construction section of the Four Major Rivers Project is caused by repeated erosion and sedimentation due to the effects of sandification caused by large dredging and flood-time reservoirs, and the head erosion of the tributaries occurs. In order to solve these problems, the riverbed maintenance work was installed, but it resulted in erosion of both sides of the river and the development of new approaches and techniques to keep the river bed stable, such as erosion and excessive sedimentation, is required. The water agent plays a role of securing a certain depth of water for the main stream by concentrating the flow so much in the center and preventing levee erosion by controlling the flow direction and flow velocity. In addition, Groyne products provide various ecological environments by forming a natural form of riverbeds by inducing local erosion and deposition in addition to the protection functions of the river bank and embankment. Therefore, after reviewing the method of determining the shape of the Groyne structure currently in use by utilizing the mobile limit flow rate and marginal reflux force, a new Critical Movement Velocity(${\bar{U}}_d$) and a new resistance coefficient formula considering the mathematical factors applicable to the actual domestic stream were developed and the measures applicable to Groyne installation were proposed.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.1
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• pp.93-101
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• 2010

This paper aims to analyze success factors for the construction of Supdari(a traditional wooden bridge to connect small streams temporarily), which is a citizens' initiative project to revitalize local community in Jeonju-River, Jeonju City. Recently Supdari has been restored for the use of belongings in local festivals. But Jeonju-River Supdari was designed and built to unite local citizens and connect river-divided villages. This project shows how investing social capital like Supdari makes the community vitalize through citizen's active participation. As a citizen leading project, there were several critical factors for sucess. At first, there were some noticeable ways to encourage local citizen's participation in online and offline. In the online, the Supdari internet cafe introduced what is a Supdari, how to make it and where we build using various media of UCCs and photos. In the offline, the small scaled model of Supdari was made and exhibited in the entrance of the village and related several seminars were hosted to discuss how to construct Supdari with citizens, local assembly men and public officials together. The Second is the movement to restore traditional and cultural resources for the community recovery triggered the supports from local councils and many civic groups. Civic groups supported ecological and structural expertise to guarantee environment friendly and stable construction. And local councils mediated citizen's and administrative office's opinions. The third is flexible administrative management to help citizen's ideas to be realized. Officials extended setting period of Supdari on the condition with the civic-control safety management.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.347-356
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• 2013

Purpose: To evaluate the visual acuity and visual performance after implantation of a aspheric multifocal (ReSTOR$^{(R)}$ SN6AD3) intraocular lens (IOL). Methods: Nineteen cataract patients (30 eyes) implanted with an aspheric multifocal IOL (ReSTOR$^{(R)}$ SN6AD3) either unilaterally or bilaterally were participated. Visual acuity (VA) and objective optical performance were evaluated at the time of preoperation, 1 week, 1 month, and 3 month after operation. At 3 month of post-operation, objective visual performance were measured and compared with the 38 eyes of 20 age-matched normal control. Distance VA was measured by using the ETDRS LCD chart and intermediate and near visual acuity were measured using Jaeger chart. Objective visual performance was assessed preoperatively and 1 week, 1 month and 3 month postoperatively using a double-pass system (Optical Quality Analysis System) with a 4-mm pupil diameter, the OSI (objective scatter index), MTF (modulation transfer function) cut off and strehl ratio. At 3 month of post-operation, visual acuity and visual performance compared with age matched normal control. Results: The uncorrected distance VA, OSI, MTF cut off and strehl ratio were significantly improved (p<0.05) until 1 month postoperatively. Visual performance of MTF cut off and strehl ratio after 3 month of operation were significantly improved compared to the normal control (p=0.063, p=0.103 respectively), however, OSI was higher than normal control. Patients implanted with aspheric multifocal IOL were satisfied with distance and near VA however, were unsatisfied with intermediate VA and reported glare and halos. Conclusions: The visual performance reaches to a stable condition in 1 month of implantation of aspheric multifocal IOL and improved to the level of age-mated normal patients. Also patients were satisfied with their quality of vision, however, intermediate VA, glare and halos were reported as complications.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.313-320
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• 2013

Purpose: This study compared the quantity of phoria for distance by new method with that by existing methods. Methods: For this study, it was selected to two existing phoria measurements, von Graefe and Maddox rod. And new method named "3D polarizing phoria measurement" was designed to measure the quantity of phoria using polarizing glasses and 3D display. Unlike existing measurement using polarized lens, newly considered method measured the quantity of phoria in condition removed perfect binocular fusion using field stop on apparatus and polarized lens. For using new method for distance, it was developed a phoria test chart. It supports three kinds of phoria measurements. Subjects were 12 (male 6, female 6). They had three phoria tests (1 sets) including new method. It was considered the effect of experimental order, so we tested all cases about experimental order. The number of cases was 6 sets, and the sample size in this experiment was 72 sets. For removing binocular fusion, lighting of the laboratory that was below 10 lx and the background color of phoria test chart was dark, RGB=(20, 20, 20). Results: Subjects were sorted into three groups. Samples with exophoria and orthophoria were 30 sets each, and those with esophoria were 12 sets. The quantity of phoria measured three tests differ from each other like "newmethod < von Graefe < Maddox rod", and there were statistically significant difference each other. Conclusions: This study has great significance in the sense that new method was the measurement with naturally removing binocular fusion without dizziness during the tests.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.177-186
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• 2015

Purpose: The Purpose of this study is to investigate if the relative legibility of optotypes affects the corrected visual acuity in visual acuity test. Methods: After measuring the relative legibility of 'Landolt ring target', 'arabic number target', 'alphabet target' by showing as a single-letter-target in 24 subjects without specific ocular diseases and ocular surgery experience, the relative legibility of 0.8, 1.0, 1.25 row of vision according to type of target in 7 types of chart were compared. After then we compared by measuring the corrected visual acuity according to type of target by using binocular MPMVA test (#7A) in 60 myopic subjects. Results: In 3 types of target the worst relative legibility target was 'Landolt ring target' with legible distance of $98.97{\pm}4.57cm$ and the best relative legibility target was 'alphabet target' with legible distance of $108.42{\pm}3.46cm$. There was no difference of the relative legibility according to type of chart or visual acuity level in the row of vision if other conditions are the same. In 1.0 and 1.25 row of vision the difference of relative legibility according to type of target was shown the statistically significant difference between 'Landolt ring target' and 'alphabet target' as $-0.07{\pm}0.06$ (p=0.02) and $-0.06{\pm}0.06$ (p=0.04) respectively. In myopia the difference of corrected visual acuity according to type of target was statistically significant difference between 'Landolt ring target' and 'arabic number target' as $-0.04{\pm}0.02$ (p=0.02) and it was especially remarkable in the low myopia. Conclusions: Measuring visual acuity with different optotypes could cause the errors in best vision measurement value because there was difference of the relative legibility according to type of target even though visual acuity level is same in the row of vision.