• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.1-9
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• 2022

Most factories deal with toxic or flammable chemicals in their industrial processes. These hazardous substances pose a risk of leakage due to accidents, such as fire and explosion. In the event of chemical release, massive casualties and property damage can result; hence, quantitative risk prediction and assessment are necessary. Several methods are available for evaluating chemical dispersion in the atmosphere, and most analyses are considered neutral in dispersion models and under far-field wind condition. The foregoing assumption renders a model valid only after a considerable time has elapsed from the moment chemicals are released or dispersed from a source. Hence, an initial dispersion model is required to assess risk quantitatively and predict the extent of damage because the most dangerous locations are those near a leak source. In this study, the dispersion model for initial consequence analysis was developed with three-dimensional unsteady advective diffusion equation. In this expression, instantaneous leakage is assumed as a puff, and wind velocity is considered as a coordinate transform in the solution. To minimize the buoyant force, ethane is used as leaked fuel, and two different diffusion coefficients are introduced. The calculated concentration field with a molecular diffusion coefficient shows a moving circular iso-line in the horizontal plane. The maximum concentration decreases as time progresses and distance increases. In the case of using a coefficient for turbulent diffusion, the dispersion along the wind velocity direction is enhanced, and an elliptic iso-contour line is found. The result yielded by a widely used commercial program, ALOHA, was compared with the end point of the lower explosion limit. In the future, we plan to build a more accurate and general initial risk assessment model by considering the turbulence diffusion and buoyancy effect on dispersion.

• Health Policy and Management
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• v.32 no.4
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• pp.356-367
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• 2022

Background: The emergence of new infectious diseases threatens public health, increasing socioeconomic damage, and national risks. This study aimed to develop an evidence-based risk assessment tool to quickly respond to new infectious diseases. Methods: The risk elements were extracted by reviewing the risk assessment methods of the World Health Organization, United States, Europe, United Kingdom, and Germany, and the validity and priority of elements were determined through expert meetings and Delphi surveys. Then, the scale and level for each risk element were defined and a final score calculation method according to the risk evaluation result was derived. The developed risk assessment tool was verified using data at the time of domestic transmission of an emerging infectious disease. Results: In case of spread of actual infectious diseases, priority is determined based on the criticality of the elements in each area of transmissibility and severity, from which the weighted score of the risk assessment is derived. Then, the risk score for each element was calculated by multiplying the average value of the risk evaluation by its weight and the evaluation risk assessment score for the two areas was calculated. At last, the final score is plotted in a matrix where the x-axis indicates the transmissibility and the y-axis the severity and plotted on the coordinate plane for time series use. Conclusion: With respect to transmissibility and severity, this risk assessment method to respond to new and re-emerging infectious diseases enables rapid and evidence-based evaluation by quantitatively and qualitatively assessing various risk elements.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.6
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• pp.23-35
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• 2023

In this study, we developed a method to determine the flood-limited water levels of agricultural reservoirs, considering both their irrigation and flood control functions. Irrigation safety and flood safety indices were defined to be applied to various reservoirs, allowing for a comprehensive assessment of the irrigation and flood control properties. Seasonal flood-limited water level scenarios were established to represent the temporal characteristics of rainfall and agricultural water supply and the safety indices were analyzed according to these scenarios. The optimal scenarios were derived using a schematic solution based on Pareto front analysis. The method was applied to Obong, Yedang, and Myogok reservoirs, and the results showed that the characteristics of each reservoir were well represented in the safety indices. The irrigation safety of Obong reservoir was found to be significantly influenced by the late-stage flood-limited water level, while those of Yedang and Myogok reservoir were primarily affected by the early and mid-stage flood-limited water levels. The values of irrigation safety and flood safety indices for each scenario were plotted as points on the coordinate plane, and the optimal flood-limited water levels were selected from the Pareto front. The storage ratio of the optimal flood-limited water levels for the early, mid, and late stages were 65-70%, 70%, and 75% for Obong reservoir, 75%, 70-75%, and 65-70% for Yedang reservoir, and 75-80%, 70%, and 50% for Myogok reservoir. We expect that the method developed in this study will facilitate efficient reservoir operations.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.14-29
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• 2006

Developments in computer technology have made possible the 3-dimensional (3-D) evaluation of hard and soft tissues in orthodontic diagnosis, treatment planning and post-treatment results. In this study, Korean adults with normal occlusion (male 30, female 30) were scanned by a 3-D laser scanner, then 3-D facial images formed by the Rapidform 2004 program (Inus Technology Inc., Seoul, Korea.). Reference planes in the facial soft tissue 3-D images were established and a 3-D coordinate system (X axis-left/right, Y axis-superior/inferior, Z axis-anterior/posterior) was established by using the soft tissue nasion as the zero point. Twenty-nine measurement points were established on the 3-D image and 43 linear measurements, 8 angular measurements, 29 linear distance ratios were obtained. The results are as follows; there were significant differences between males and females in the nasofrontal angle $(male:\;142^{\circ},\;female:\;147^{\circ})$ and transverse nasal prominence $(male:\;112^{\circ},\;female:\;116^{\circ})$ (p<0.05). The transverse upper lip prominence was $107^{\circ}$ in males, $106^{\circ}$ in females and the transverse mandibular prominence was $76^{\circ}$ in both males and females. Li-Me' was 0.4 times the length of Go-Me'(mandibular body length) and the mouth height was also 0.4 times the width of the mouth width. The linear distance ratio from the coronal reference plane of FT, Zy, Pn, ULPm, Li, Me' was -1/-1/1/0.5/0.5/-0.6 respectively. The 3-D facial model of Korean adults with normal occlusion were be constructed using coordinate values and linear measurement values. These data may be used as a reference in 3-D diagnosis and treatment planning for malocclusion and dentofacial deformity patients and applied for 3-D analysis of facial soft tissue changes before and after orthodontic treatment and orthognathic surgery.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.73-78
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• 2015

Purpose : Under the assumption of change to the amplitude based sorting, the study will use four dimensional computed tomography imaging (4DCT) arrayed using the phase based sorting to analyze the respiratory phase difference. Materials and Methods : The study analyzed the 4DCT (4-dimensional computed tomography) images of 10 liver cancer patients that were treated with respiratory gated radiotherapy from 2015 February to March. Using RPM respiratory gating (RPM 1.7.5, Varian, USA) equipment, imaging according to respiratory cycle of phase based sorting was acquired and using a treatment planning system (Pinnacle 9.2, Philips, USA) the acquired imaging according to respiratory cycle was used to measure the abdominal movement value by respiratory cycle. The measuring point was the point where the center point of the Marker Block and the body surface met in the 50% phase image and here the coordinate values Lateral, Vertical, Longitudinal (X, Y, Z) were set as reference points, and on the X, Z plane identical to the reference point, using the identical method the Y axis coordinate value of each 0%, 30%, 40%, 50%, 60%, 80% phase images were acquired to quantitatively measure the variation of distance to the Y axis. The abdominal movement value according to respiration was applied to the theoretical model that the value decreases linearly from maximum inhalation to maximum exhalation to divide the variation of my value to predict as amplitude value by respiratory cycle and conversely the variation in amplitude was recalculated with the phase variation deviation value to analyze. Results : The deviation value between expected value and actual location was the largest in the 30% phase with 0.24 cm, and standard deviation was also the largest in 30% phase with 0.13 cm. The effective value of the deviation value derived from the average of the deviation squared value of each patient appeared as minimum 0.7 cm, maximum 0.18 cm, average 0.12 cm, and standard deviation 0.4 cm. Also by dividing the actual movement distance value with the peak expiration value then converting it into %Phase, the deviation value with actual phase 16.5% in 30% phase, 10.0% and 40% phase, 10.0% and 60% phase, 15.4% and 80% phase, and overall average about 13%, and arraying based on amplitude, phase shift occurred and further it was from peak expiration the chance of deviation occurrence was increasingly measured. Conclusion : Based on the results of the study there were differences between value acquired based on theoretical model and actual value. Therefore in respiratory gated radiotherapy using external surrogates, there needs to be establishment of respiration gated radiation system that avoids the combination of two Sorting methods considering that there will be occurrence of treatment and corresponding clinical differences due to the phase difference that occur due to the Amplitude based Phase Sorting.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.139-151
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• 2018

The National Base Map construction consists of the regular correction work of dividing the whole country into two regions and carrying out the modification Plotting by aerial photographs every two years as well as the real time updating work of correcting the major change feature within two weeks by the field survey and the As-Built Drawing. In the case of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) used for real time updating work of the National base map, the coordinate transformation error is included in the positional error when applied to the National Base Map based on the World Geodetic Reference System as the coordinate system based on the Regional Geodetic Reference System. In addition, National Base Map is registered based on the outline(eaves line) of the building in the Digital Topographic Map, and the Cadastral and Architecture are registered based on the building center line. Therefore, the Building Object management standard is inconsistent. In order to investigate the improvement method, the network RTK survey was conducted directly on a location of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) and the problems were analyzed by comparing with the plane plotting position reference in National Base Map. In the case of the general structure with the difference on the Building center line and the eaves line, beside the location information was different also the difference in the ratio of the building object was different between Building center line and the eave. In conclusion, it is necessary to provide the Base data of the double layer of the Building center line and the outline of the building(eaves line) in order to utilize the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS). In addition, it is necessary to study an organic map update process that can acquire the up-to-dateness and the accuracy at the same time.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.866-873
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• 2012

IgY (Immunoglobulin Yolk) is a specific antibody in egg yolk, and it protects human body from virus and antigen. There are a lot of egg yolk components such as lipoprotein and protein. To separate IgY, HPLC (High Performance Liquid Chromatography) and precipitation were used in a batch mode and SMB (Simulated Moving Bed) was adopted for continuous purification of yolk proteins. IgY and other proteins in yolk were separated by using three-zone and four-zone SMB chromatography. Before performing SMB experiments, batch chromatography simulation parameters and adsorption isotherms were obtained. The parameters of batch chromatography were used to simulate SMB using Aspen chromatography. To compare three-zone and four-zone SMB chromatography, simulations in $m_2-m_3$ plane on the triangle theory were carried out. In terms of concentration and purity of both IgY and other lipoproteins, 3-zone SMB process is considered as ideal at the vertex of triangle ($m_2$, $m_3$=0.1, 1.1). 4-zone SMB yields the highest IgY purity at the coordinate ($m_2$, $m_3$=0.06, 0.5), which is the pure raffinate region. In 3-zone SMB without recycle, other lipoproteins in extract are largely affected in purity by small shift from the vertex of triangle ($m_2$, $m_3$=0.1, 1.1).

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.509-529
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• 1992

Skeletal Class III malocclusion is one of the most difficult type to treat and stabilize. For a child with developing skeletal Class III malocclusion, the treatment objective would be to stimulate maxillary growth, particulary one who has markedly deficient maxilla, and to restrain excessive mandibular growth. In order to stimulate the maxillary growth, maxillary protraction appliance is the one of the effective orthopedic appliances in skeletal Class III. The purposes of this study were as follows ; evaluation of the skeletal and dental changes of the maxillary protraction in children with Class III Maxillary deficiency , comparison of the clinical effects between the group with RPE and labiolingual intraoral appliances , comparison of the clinical effects and stability related to the ages of the patients : stability of the maxillary protraction about 1 year after retention. The subjects consisted of 60 children between the ages of 8 and 13.4 who were diagnosed as Class III with maxillary deficiency and were treated with Face Mask (Delaire Type) from the Dept. of Orthodontics Yong Dong Severance Hospital, Yonsei University. 48 children wore the RPE and 12 children wore Labiolingual Appliance. Lateral Cephalograms were taken for each patient at before and after correction of anterior cross-bite in 60 children, and after an observation period of 10 to 14 months in 19 children. X and Y coordinate of 10 landmarks were analyzed using a horizontal line through sella and rotated $6^{\circ}$ down anteriorly as the horizontal reference axis, and a perpendicular verticual line through sella as the vertical reference axis. Each of the 31 measurents (10 verticals, 10 horizontals, 2 angles and 9 others) was statistically analyzed using SPSS/PC statistics. The results are as follows; 1. After maxillary protraction the maxilla and maxillary teeth moved downward and forward, while the mandible and mandibular incisor rotated downward and backward. 2. Maxillary protraction with rapid palatal expansion appliance was more effective than with labiolingual appliance. 3. More downward movement of the posterior palatal plane obserbed with maxillary protraction doing the midpalatal suture opening than with protraction after finishing the palatal expansion 4. The clinical effects of protraction and changes of the retention periods were not statistically significant among the age groups. 5. During the retention period, maxilla and maxillary teeth, and mandible and mandibular teeth moved downward and forward, however the mandibular changes were larger than the maxillary changes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.21-30
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• 2012

When two bands have different look angle in a space-borne camera system, the registration between two bands is required. The registration cannot be modeled with constant parameters because of dynamic of platform and parallax effect. The parallax effect is caused by terrain relief, hence it causes local distortion between two bands. Therefore, the terrain relief correction in order to reduce the parallax effect is required for better registration result, especially for high resolution image data. Such terrain relief correction also can be applied to image data acquired from multiple detectors with different look angle within a band, which is a one of commonly used configuration for a wider swath in space-borne camera system, in order to reduce the distortion between detectors. The RFM is a popular abstract model in remote sensing field, which gives us the relationship between the image plane and geodetic coordinate system. Therefore, we propose a terrain relief correction method based on the RFM. The experiment showed very promising result.

• The Journal of the Korean life insurance medical association
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• v.2 no.1
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• pp.152-181
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• 1985

A statistical analysis on the cardiothoracic ratio in insurance medicine was carried out for 5,200 insured persons who were medically examined including photofluorography of the chest at the Honam medical department, Dong Bang life insurance Company, Ltd from November, 1979 to August, 1984. The results were as follows: 1. The mean value of the cardiothoracic ratio in all of the insured was $44.2{\pm}4.3%$. The mean value of the cardiothoracic ratio was $43.1{\pm}4.1%$ in all males and $45.2{\pm}4.2%$ in all females, and the difference of the values between males and females showed statistical significance(P<0.001). In each age group, the mean value of the cardiothoracic ratios of female was higher than that of male without exception and the difference of the values between males and females showed statistical significance(P<0.001). The mean value of the cardiothoracic ratio showed gradual increase with age from the second to sixth decade in male(P<0.05 or 0.001 after fourth decade) and from the second to seventh decade in female(P<0.05 or 0.001 from the second to sixth decade). 2. Correlation between both sexes and among age groups relating to the cardiothoracic ratios of the insureds seen to be a physiological phenomenon of the cardiac size and should be considered on the rating of the cardiothoracic ratio. Based on the correlation above mentioned and an author's assumption that the incidence of normal and abnormal cardiothoracic ratios in each age group would show the same rate in male and female, author prepared a modified rating table from the existing table; in male group the existing rating table is used and in female group the ratings of 0, 30-50, 50-100 and 100-D are to calculate by the cardiothoracic ratio of 51%or under, 52-56%, 57-61% and 62% or over respectively in the age group below 39, by the cardiothoracic ratio of 52% or under, 53-57%, 58%-62% and 63% or over respectively in the age group of 40-49, by the cardiothoracic ratio of 53% or under, 54-58%, 59-63% and 64% or over respectively in the age group over 60. 3. The relative frequency distribution polygons of the cardiothoracic ratio of both sexes drawn in a pair on one coordinate plane revealed lying in juxtaposition each other horizontally and showed the shifting of females polygon to male's one toward the direction of greater value of the cardiothoracic ratio at a short distance which increased gradually with age. 4. The minimum cardiothoracic ratio was 31.2% and the maximum cardiothoracic ratio was 63.6% in all of the insured. 5. In each age group, no significant sex difference was found in the relative frequency distribution of ratings by the cardiothoracic ratios of 5,200 insureds by using the rating table modified by author, while significant sex difference was found by using the existing rating table.