• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.19 no.1
• /
• pp.57-65
• /
• 2007

Shallow water waves are hindcasted from sea wind fields, which include wave transformations such as shoaling, refraction, diffraction, reflection and wave breaking. In case of estimating sea wind field in shallow water, the sea wind revised from free wind obtained by the typhoon model is widely used. However, this method is not able to consider the effect of land topography on the wind field, which will be important factor for shallow water wave forecasting and hindcasting. In this study, therefore, the effect of land topography on sea wind field in shallow water is investigated for shallow water wave forecasting and hindcasting with high accuracy. The 3-D MASCON model is introduced to consider the influence of land topography on the wind field. And, for two areas divided by the topographical characteristics, i.e. shielded and opened coastal areas, sea wind field is examined by comparison between initial wind field by typhoon model and modified wind field by 3-D MASCON model. Finally, applying these sea wind fields to SWAN model, the results of shallow water wave calculated in shielded and opened coastal areas are compared, and, also, the effect of MASCON model on shallow water wave forecasting and hindcasting is discussed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.472-477
• /
• 2017

Oil spills cause a lot of damage to the environment. Oil destroys the water environment and ecosystem in a very short period of time once they are contaminated by it, it takes a lot of time to recover from the contamination and the cleaning process is very difficult. Therefore, oil detectors are greatly needed as they can monitor any oil spills over the sea, rivers, and lakes. There are two kinds of technology available for detecting oil, viz. the contact and non-contact types. The former is based on the use of the conductivity, capacitance and microwaves, while the latter employs infrared, UV, laser, optic and radar technologies. As there are also various hurdles in the measuring of oil on water, such as the presence of waves, refraction of light, temperature and saltiness, it is imperative to select the right oil detector which is appropriate for the specific environment. In this study, a contact type oil detector is developed, which can be used in oil related industries, such as refineries, petrochemical companies, and power generation stations. The detector is made up of the sensor module, which floats on the water, and the controller which processes the signal coming from the sensor module and displays it. It is designed in such a way that the existence of oil is detected through the sensor and the change in the permittivity is observed to determine the volume and type of spilled oil.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.3
• /
• pp.255-264
• /
• 2011

Purpose: To study the effect of hyaluronic acid(HA), which was widely used in artificial tears, multi-purpose solution(MPS), cosmetics, and drug acting on the musculo-skeletal system, in wettability and comfort of contact lens, we compared HA including lens(+HA) with HA excluding lens(-HA) by clinical evaluation. Methods: During four weeks, the selected 28 university student volunteers who did not have any eye disease wore +HA contact lens on their right eyes, and -HA contact lens on their left eyes, and then compared right eyes to left eyes as control. After prescribing by spherical equivalent calculation, over-refraction by auto-refractometer, and contact lens wearing for two weeks and four weeks, tear evaluation, the anterior of eyes examination, fitting convenience evaluation, surface wetting test, surveys were checked up. Results: Compared with the control group (-HA contact lens), +HA contact lens provided better wetting properties. The amount of released tear in -HA contact lens group became less in four weeks than before, but that in +HA contact lens group showed no significant difference from the initial one. In terms of the redness in eye, there was no significant difference between +HA and -HA contact lens groups. Fitting of +HA contact lens on eye was much easier than the control, -HA contact lens. From the results of survey, comfort, wettability, ease of cleaning, and dryness of eye in +HA contact lens group were generally better than those of -HA group, but redness and contact lens handling showed little difference. Conclusions: The addition of HA in soft contact lens(+HA) may enhance the wettability of lens during lens wearing, resulted in the better comfortable wearing of lens eventually.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.3
• /
• pp.65-73
• /
• 2009

Purpose: This study was conducted to investigate the changes in distance refractive power and reading addition that occur after wearing corrective glasses for prebyopia. Methods: The subjects aged 42 to 75 years who had no ophthalmologic diseases and did not undergo cataract or retina surgery, had a corrected visual acuity of 20/20 and did not have a previous history of wearing corrective glasses for presbyopia. These subjects were divided into 3 groups: the control, reading spectacles and multifocals wearing group and they were measured for distance refractive power and reading addition at their visit. The maximum follow-up period was 73 months. Results: As for distance refractive power, the power tends to shift to hyperopia depending on age (r=0.486, p<.001) and 50.0% of the subjects increased plus power during this study period. Plus power Increments per year in distance refractive power in the reading spectacle wearing group were significantly different with control and multifocals wearing group (p<.05). On the other hand, the multifocals wearing group's increments were not different with control. Increments in reading addition were also increased in the reading spectacles group than in the control and multifocals wearing groups (p<.05). Conclusions: The age related hyperopic shift could be occurred in the elderly people, routine refraction is mandatory. And reading spectacles could induce an age related hyperopic shift and the additional need for reading addition that the prescription of multifocals may reduce changes in distance refractive power and reading addition.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.3
• /
• pp.59-63
• /
• 2009

Purpose: To investigate the near horizontal heterophoria of the college students in their twenties on north Kyonggi Province. Methods: The all subjects had not experienced any ocular surgery and have no disease and their mean age is 22.9. As 122 subjects, they are 50 emmetropes and 72 ametropes. The ametropes are all myopia. After distance visual acuity correction with subjective and objective refraction test, evaluated their horizontal heterophoria with red maddox rod. Results: In maddox rod test, the subjects consist of orthophoria 4.9%, esophoria 9.8% and exophoria 85.3%. In the emmetropes orthophoria is 8%, esophoria is also 8% and exophoria is 84%. In the ametropes orthophoria is 2.8%, esophoria is 11.1% and exophoria is 86.1%. The mean size of horizontal heterophoria is esophoria 3.59PD (prism diopter), exophoria 7.04PD and in the emmetropes esophoria is 3.25PD, exophoria is 6.60PD. In the ametropes esophoria is 3.75PD and exophoria is 7.34PD. Conclusions: In the emmetropoes the orthophoria is more than in the ametropes and the esophoria and exophoria is more in the ametropes. But the differences between the heterophoria and emmetropia or ametropia were not significant (p>0.05). The mean size of heterophoria is higher in the ametropes than in the emmetropoes. The distribution range of heterophoria is wider in the male subjects than the female subjects.

• Journal of The Korean Ophthalmological Society
• /
• v.59 no.12
• /
• pp.1173-1180
• /
• 2018

Purpose: We evaluated the postoperative accuracy of intraocular lens power prediction for patients undergoing phacotrabeculectomy and identified preoperative factors associated with refractive outcome in those with primary open-angle glaucoma (POAG). Methods: We retrospectively reviewed the medical records of 27 patients who underwent phacotrabeculectomy to treat POAG. We recorded all discrepancies between predicted and actual postoperative refractions. We compared the data to those of an age- and sex-matched control group that underwent uncomplicated cataract surgery during the same time period. Preoperative factors associated with the mean absolute error (MAE) were identified via multivariate regression analyses. Results: The mean refractive error of the 27 eyes that underwent phacotrabeculectomy was comparable to that of the 27 eyes treated via phacoemulsification (+0.02 vs. -0.01 D, p = 0.802). The phacotrabeculectomy group exhibited a significantly higher MAE (0.65 vs. 0.35 D, p = 0.035) and more postoperative astigmatism (-1.07 vs. -0.66 D, p = 0.020) than the phacoemulsification group. The preoperative anterior chamber depth (ACD) and the changes in the postoperative intraocular pressure (IOP) were significantly associated with a greater MAE after phacotrabeculectomy. Conclusions: POAG treatment via combined phacoemulsification/trabeculectomy was associated with greater error in terms of final refraction prediction, and more postoperative astigmatism. As both a shallow preoperative ACD and a greater postoperative change in IOP appear to increase the predictive error, these two factors should be considered when planning phacotrabeculectomy.

• Food Science and Preservation
• /
• v.16 no.4
• /
• pp.534-540
• /
• 2009

To decrease human intake of animal fats, changes in the physicochemical characteristics of pork loins prepared by different cooking methods (boiling, steaming, baking, and frying) were investigated. The moisture content of the cooked meat decreased with all methods, and the crude lipid content decreased with all methods except frying. The cooking loss and the moisture drain rate of the cooked meats were greatest during frying, whereas the lipid drain rate was greatest with steaming. The pH value increased during all cooking processes tested. The acid value and refraction index of meat fat markedly increased by steaming and frying, respectively. The hardness, gumminess, chewiness, and cohesiveness of the meat increased notably during frying. The springiness decreased by both boiling and steaming, but rarely by baking or frying. The CIE $L^{\ast}$ (lightness) value markedly increased by both boiling and steaming, and the CIE $a^{\ast}$ (redness) value decreased notably during both boiling and steaming. The CIE $b^{\ast}$ (yellowness) value increased by both baking and frying, but usually did not increase with either boiling or steaming. The composition of fatty acids was not significantly affected by any cooking methods except frying.

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

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.926-932
• /
• 2017

Image distortion can occur when photographing deep sea targets with an optical camera. This problem arises because sunlight is not sufficiently transmitted due to seawater and various floating particles of dust. Particularly, color distortion takes place, causing green and blue color channels to be over emphasized due to water depth, while distortion of boundaries also occurs due to light refraction by seawater and floating particles of dust. These distortions degrade the overall quality of underwater images. In this paper, we analyze underwater images of the bottom of vessels. Based on the results, we propose a technique for color correction and edge enhancement. Experimental results show that the proposed method increases edge clarity by 3.39 % compared to the effective edges of the original underwater image. In addition, a quantitative evaluation and subjective image quality evaluation were concurrently performed. As a result, it was confirmed that object boundaries became clear with color correction. The color correction and contour enhancement method proposed in this paper can be applied in various fields requiring underwater imaging in the future.

• Journal of Popular Narrative
• /
• v.26 no.1
• /
• pp.77-102
• /
• 2020

This article analyzes 'book traveler' stories as a new sub-genre of Korean fantasy web fiction. Formal innovation is revealed as the major motivation of Korean fantasy web fiction's narratives. Furthermore, the imagination of social resistance was presented as the formal devices of the genre. These theses were performed during the analysis of the two characteristics of the genre. In this genre, the main character is the writer or reader of fantasy stories. He moves into a novel he is describing or reading. The original novel, which was entered by the main character, is a space characterized by the custom of a typical fantasy genre. Therefore, the main character actually experiences cliché, typical genre devices and plots. The most important action for the main character here is to 'bend' the custom of the original. Therefore, this genre is in the form of the main motive being the refraction of typology. Meanwhile, the main character is not the central character of the original, but a secondary figure. The central character of the original book is usually from the ruling class, which monopolizes the good resources of society. At this time, the genre creates a subversive situation in which the social underdog goes beyond the social power through plots that overwhelm the central figure. It converts the reader's social desire into a genre device. To summarize, the latest trend in Korean web novel fantasy has captured scenes of renewed Korean genre literature practices. It sensitively reflects the social context of the contemporaries and the reader's desire. Thus, the Korean web novel fantasy has reflected both its internal conditions and its social context.