• Advances in aircraft and spacecraft science
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• v.11 no.1
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• pp.83-103
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• 2024

Adhesive bonding is currently widely used in many industrial fields, particularly in the aeronautics sector. Despite its advantages over mechanical joints such as riveting and welding, adhesive bonding is mostly used for secondary structures due to its low peel strength; especially if it is simultaneously exposed to temperature and humidity; and often presence of bonding defects. In fact, during joint preparation, several types of defects can be introduced into the adhesive layer such as air bubbles, cavities, or cracks, which induce stress concentrations potentially leading to premature failure. Indeed, the presence of defects in the adhesive joint has a significant effect on adhesive stresses, which emphasizes the need for a good surface treatment. The research in this field is aimed at minimizing the stresses in the adhesive joint at its free edges by geometric modifications of the ovelapping part and/or by changing the nature of the substrates. In this study, the finite element method is used to describe the mechanical behavior of bonded joints. Thus, a three-dimensional model is made to analyze the effect of defects in the adhesive joint at areas of high stress concentrations. The analysis consists of estimating the different stresses in an adhesive joint between two 2024-T3 aluminum plates. Two types of single lap joints(SLJ) were analyzed: a standard SLJ and another modified by removing 0.2 mm of material from the thickness of one plate along the overlap length, taking into account several factors such as the applied load, shape, size and position of the defect. The obtained results clearly show that the presence of a bonding defect significantly affects stresses in the adhesive joint, which become important if the joint is subjected to a higher applied load. On the other hand, the geometric modification made to the plate considerably reduces the various stresses in the adhesive joint even in the presence of a bonding defect.

• Journal of Magnetics
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• v.20 no.4
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• pp.381-386
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• 2015

The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.

• Journal of Intelligence and Information Systems
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• v.18 no.3
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• pp.79-96
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• 2012

As the pace of competition dramatically accelerates and the complexity of change grows, a variety of research have been conducted to improve firms' short-term performance and to enhance firms' long-term survival. In particular, researchers and practitioners have paid their attention to identify promising technologies that lead competitive advantage to a firm. Discovery of promising technology depends on how a firm evaluates the value of technologies, thus many evaluating methods have been proposed. Experts' opinion based approaches have been widely accepted to predict the value of technologies. Whereas this approach provides in-depth analysis and ensures validity of analysis results, it is usually cost-and time-ineffective and is limited to qualitative evaluation. Considerable studies attempt to forecast the value of technology by using patent information to overcome the limitation of experts' opinion based approach. Patent based technology evaluation has served as a valuable assessment approach of the technological forecasting because it contains a full and practical description of technology with uniform structure. Furthermore, it provides information that is not divulged in any other sources. Although patent information based approach has contributed to our understanding of prediction of promising technologies, it has some limitations because prediction has been made based on the past patent information, and the interpretations of patent analyses are not consistent. In order to fill this gap, this study proposes a technology forecasting methodology by integrating patent information approach and artificial intelligence method. The methodology consists of three modules : evaluation of technologies promising, implementation of technologies value prediction model, and recommendation of promising technologies. In the first module, technologies promising is evaluated from three different and complementary dimensions; impact, fusion, and diffusion perspectives. The impact of technologies refers to their influence on future technologies development and improvement, and is also clearly associated with their monetary value. The fusion of technologies denotes the extent to which a technology fuses different technologies, and represents the breadth of search underlying the technology. The fusion of technologies can be calculated based on technology or patent, thus this study measures two types of fusion index; fusion index per technology and fusion index per patent. Finally, the diffusion of technologies denotes their degree of applicability across scientific and technological fields. In the same vein, diffusion index per technology and diffusion index per patent are considered respectively. In the second module, technologies value prediction model is implemented using artificial intelligence method. This studies use the values of five indexes (i.e., impact index, fusion index per technology, fusion index per patent, diffusion index per technology and diffusion index per patent) at different time (e.g., t-n, t-n-1, t-n-2, ${\cdots}$) as input variables. The out variables are values of five indexes at time t, which is used for learning. The learning method adopted in this study is backpropagation algorithm. In the third module, this study recommends final promising technologies based on analytic hierarchy process. AHP provides relative importance of each index, leading to final promising index for technology. Applicability of the proposed methodology is tested by using U.S. patents in international patent class G06F (i.e., electronic digital data processing) from 2000 to 2008. The results show that mean absolute error value for prediction produced by the proposed methodology is lower than the value produced by multiple regression analysis in cases of fusion indexes. However, mean absolute error value of the proposed methodology is slightly higher than the value of multiple regression analysis. These unexpected results may be explained, in part, by small number of patents. Since this study only uses patent data in class G06F, number of sample patent data is relatively small, leading to incomplete learning to satisfy complex artificial intelligence structure. In addition, fusion index per technology and impact index are found to be important criteria to predict promising technology. This study attempts to extend the existing knowledge by proposing a new methodology for prediction technology value by integrating patent information analysis and artificial intelligence network. It helps managers who want to technology develop planning and policy maker who want to implement technology policy by providing quantitative prediction methodology. In addition, this study could help other researchers by proving a deeper understanding of the complex technological forecasting field.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.127-134
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• 2008

Purpose: The purpose of this study was to determine the expected values of accommodation and vergence system for analysis of binocular vision. Methods: Seventy three healty subjects without past history of eye disease were selected for this study, Patients showing clinical binocular anomalies including manifest squint and intermittent heterotropia were excluded and data was collected on 54 patients(mean age, 25.3${\pm}$2.7 year). Near point of convergence, distance and near phoiras were measured based on objective deviation angle. And then AC/ A ratio, relative accommodation were measured and all of the data were compared with the Morgan's expected values. Results: The values of distance and near heterophoria were 1.24${\pm}$2.72${\Delta}$ and 2.70${\pm}$4.91${\Delta}$ respectively and the gradient AC/A ratio was 3.92${\pm}$2.17${\Delta}$/D which were all about the same compared with the Morgan's expected values. The values of distance negative fusional convergence was same, however, distance positive fusional convergence was 7${\Delta}$ greater than the Morgan's one. There were no significant differences in the range values of both near vergences while the range of distance vergence was relatively larger than the Morgan's one. Positive relative accommodation was +0.37D greater and negative relative accommodation was -0.63D greater than the Morgan's values. Conclusions: The findings in this study appear that the Morgan's expected values have a possibilities of including considerable proximal convergence value. In comparison with Morgan's values, Korean's normal expected values have much different values of especially BO limit, so if the Morgan's values are directly applied to binocular vision analysis for Korean people, it may lead to an inaccurate binocular vision diagnosis. This results can be used to diagnose the accommodation and vergence system of Korean normal young adults.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.325-338
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• 2023

Korean fir (Abies koreana Wilson) is one of the most important environmental indicator tree species for assessing climate change impacts on coniferous forests in the Korean Peninsula. However, due to the nature of alpine and subalpine regions, it is difficult to conduct regular field surveys of Korean fir, which is mainly distributed in regions with altitudes greater than 1,000 m. Therefore, this study analyzed the vegetation change trend of Korean fir using regularly observed remote sensing data. Specifically, normalized difference vegetation index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS), land surface temperature (LST), and precipitation data from Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievalsfor GPM from September 2003 to 2020 for Hallasan and Jirisan were used to analyze vegetation changes and their association with environmental variables. We identified a decrease in NDVI in 2020 compared to 2003 for both sites. Based on the NDVI difference maps, areas for healthy vegetation and high mortality of Korean fir were selected. Long-term NDVI time-series analysis demonstrated that both Hallasan and Jirisan had a decrease in NDVI at the high mortality areas (Hallasan: -0.46, Jirisan: -0.43). Furthermore, when analyzing the long-term fluctuations of Korean fir vegetation through the Hodrick-Prescott filter-applied NDVI, LST, and precipitation, the NDVI difference between the Korean fir healthy vegetation and high mortality sitesincreased with the increasing LST and decreasing precipitation in Hallasan. Thissuggests that the increase in LST and the decrease in precipitation contribute to the decline of Korean fir in Hallasan. In contrast, Jirisan confirmed a long-term trend of declining NDVI in the areas of Korean fir mortality but did not find a significant correlation between the changes in NDVI and environmental variables (LST and precipitation). Further analyses of environmental factors, such as soil moisture, insolation, and wind that have been identified to be related to Korean fir habitats in previous studies should be conducted. This study demonstrated the feasibility of using satellite data for long-term monitoring of Korean fir ecosystems and investigating their changes in conjunction with environmental conditions. Thisstudy provided the potential forsatellite-based monitoring to improve our understanding of the ecology of Korean fir.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.252-260
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• 1996

In this article, we investigate into the structural changes of liposome to design its functional membranes by the synthesis of two types of liposomes, DPPC liposome and DTAB of hydrocarbon substance/DPPC liposome. The changes of membrane structures are evaluated by the CF fluorescent intensity measured above and below the phase transition temperature of the membrane, $t_c=41^{\circ}C$. CF fluorescent intensities are enhanced by the CF leakage from DPPC liposome at $45^{\circ}C$, while no changes are observed at $20^{\circ}C$. Under the same conditions, it is observed that the intensity enhanced by CF leakage from DPPC/DTAB liposome is larger than that of DPPC liposome alone, which suggests that DPPC/DTAB liposome has irregular arrangement. Under the presence of $Ca^{2+}$, Quin 2 fluorescent intensity in either DPPC liposome or DPPC/DTAB liposome is significantly increasing at $45^{\circ}C$, while almost none of the changes are observed at $20^{\circ}C$. The fluorescent intensity of DPPC liposome turns out to be larger than that of DPPC/DTAB liposome, which suggests that the DPPC/DTAB liposome is structurally more stable than the DPPC liposome. Additionally, when the analysis is done to observe changes in the shapes of membrane surfaces with ANS fluorescent, ANS fluorescent under DPPC or DPPC/DTAB liposome shows each of different appearances at $45^{\circ}C$ and $20^{\circ}C$ respectively. This result indicates that its respective membrane fluidity is changing above and below of the designated temperatures in phase transition. As to the magnitude of change of its membrane fluidity, DPPC liposome is much larger than DPPC/DTAB liposome. As far as the temperature in phase transition measured by DSC are concerned, it is $41^{\circ}C$ and $32^{\circ}C$ for DPPC and DPPC/DTAB liposome respectively, which suggests that DPPC/DTAB liposome has an irregular molecular arrangement in its structure. That is, it is summed up that DPPC/DTAB turns out to be structurally stable, even so, its structure is irregularly arranged.

• Research in Community and Public Health Nursing
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• v.11 no.1
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• pp.262-277
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• 2000

In order to find out the sex- and age-related prevalence rate of allergic diseases in the community. as well as the causes of those diseases. questionnaires were given to 2.415 subjects (1.206 males and 1.209 females) from May to June. 1998. As a second stage. skin tests were given to 452 of the original subjects between July and August. 1998. Finally. from March to November 1999. the results of the tests were compared with those of other countries to make a comparative analysis of epidemiological research on allergic diseases. The results of this study were as follows: The frequency of allergic symptoms by sex was 50.1% in males and 56.7% in females. respectively, which displayed significant difference between males and females(p<.01). By age, the frequency of allergic symptoms in males was highest for those under the age of 9 at 60.6%, whereas in females the highest frequency was between the ages of 30 to 39 at 75.1 %. The relationship between economic level of the subjects and their frequency of allergic diseases showed significant difference (P<.05). There was a high degree of correlation between family history and the frequency of allergic diseases(P<.01). In allergic symptoms, the highest prevalence in both males and females occurred with urticaria, itch and skin rash (33.6% with males and 38.0% with females). Rhinitis, nasal blocking and sneezing had the second highest frequency in both sexes (11.8% of males and 14.0% of females). With regard to the causes of allergic symptoms among the people with allergies, the rate in males was 30.1% in food. 25.0% in pollen, and among females the rate was 30.7% in food, 26.6% in pollen. The frequency of food allergies by sex was 25.6% in males and 25.8% in females, with little difference between males and females, and by age, males of the ages between 40 to 49 and females of the ages between 30 and 39 showed the highest frequency, 31.8% and 32.6% respectively. Among 585 people with food allergies, the sympoms occurring with the allergy in males were 81.5% with urticaria, itch and skin rash. 5.9% with diarrhea and stomachache, and 5.2% with rhinitis, nasal blocking and sneezing. Among females with food allergies, the symptoms were 82.6% with urticaria, itch, skin rash, 9.1% with diarrhea and stomachache, and 4.7% with rhinitis, nasal blocking and sneezing. The type of food most often causing allergy in males was mackerel (6.6%) and females peaches (7.4%). In respect to a positive rate in the skin test by sex, of the 379 males taking the skin test, 21.4% were positive for allergies, whereas 14.7% of the 346 females tested were positive. Among food items found to cause positive allergic reactions, hops had the highest frequency in males (58.9%) and whole eggs had the greatest effect on females (36.4%). The estimated prevalence of food allergies in terms of skin tests was 5.0% of 1.206 males and 3.6% of 1.209 females. In the estimated frequency of food allergy by age group, males of the ages between 40 and 49 and females of the ages from 30 to 39 had the highest rate (6.5% with males and 4.5% with females). In a comparative analysis of epidemiological research on allergic diseases by country group, allergic diseases occurred in 18-50% of each population studied, and the occurrence of allergic diseases when categorized according to symptoms displayed the following as such: allergic rhinitis (3.8-52%), allergic asthma (1.6-17%), and atopy dermatitis (0.33-20.4%). The prevalence of food-related allergies was 6.6-64.9% and the foods causing allergies frequently included milk, eggs, eggs, peanuts, fish, etc.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.231-237
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• 1999

It is very distinctive that sigumjang meju was produced with smoking after molding. Every shapes of traditional sigumjang meju gathered from Kyeongsangbukdo were doughnut types. Fermentation time were $60{\sim}90$ days. Aerobic bacteria were $6.8{\times}10^7\;cfu/g$, and anaerobic bacteria, yeasts, molds count $3.2{\times}10^6\;cfu/g,\;1.0{\times}10^6\;cfu/g\;and\;4.0{\times}10^6\;cfu/g$, respectively. Analysis showed: moisture content, $10.5{\pm}2.6%$; fat content, $2.9{\pm}1.1%$; protein content, $8.3{\pm}0.7%$; ash content, $3.8{\pm}0.7%$; pH, $6.0{\pm}0.5$; L-value, $54.5{\pm}4.7$; a-value, $+3.3{\pm}0.7$; and b-value, $+10.7{\pm}2.0$. K content was the most in quantity among the minerals in sigumjang meju. Maltose was most abundant component among the tested sugars followed by mannitol. Total content of amino acid was $1524.9{\pm}1295.3\;mg%$. Proline was the most abundant component among the amino acids. The ratio of essential amino acid was $30.0{\pm}12.9%$. The principal fatty acids were 18:2, 18:1 and 16:0. Saturated fatty acid and mono unsaturated fatty acid were $23.2{\pm}1.9%\;and\;23.5{\pm}5.2%$, respectively. The PUFA/SFA was $2.3{\pm,}0.3$ which higher than 1.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.37-45
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• 2003

This study investigated that total 1071 reading glasses wearers (male 432, female 639) without any eye disease or deformation in eyelid, orbit, eyeball (over 50 years old), were tested. Reading pupillary distance of 524 (male 202, female 322) of 1071 were examined and reading glasses power was examined for all 1071 patients. As a result of average reading diopters analysis by sex. male had S+2.34Dptr, female had S+2.23Dptr in average and male had a little more average power than female by 0.11Dptr. However, the difference was not much enough and by aging accommodation reduction changes were applied to both male and female. After dividing ready-made reading glasses on sale in optical shops into 5 groups by F.P.D. the average D.B.O.C(distance between optical centers) of each 5 group was examined (1st group 64.04 mm, 2nd group 66.96 mm, 3rd group 68.28 mm, 1th group 62.03 mm, 5th group 72.00 mm : the average of all groups was 66.96 mm : each group included 3 random samples : 195 ready-made reading glasses were measured), and compared with the average reading P.D of males and females (male 60.04 mm, female 58.23 mm). The result showed D.B.O.C of ready-made reading glasses on sale was bigger than the average reading P.D of them. The result reviewed the average range for male was $0.23{\Delta}(minimum){\sim}5.06{\Delta}(maximum)$, and for female was $0.46{\Delta}{\sim}5.79{\Delta}$. In conclusion when wearing ready-made reading glasses, female got more effected by average $0.45{\Delta}$ because reading P.D of female was smaller than that of male.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.485-494
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• 2000

According to the worldwide interest in controlling $CO_2$ which contributes to green house effect. new techniques of reducing $CO_2$ are under development. We have developed new technique for reducing $CO_2$. In low $CO_2$ concentration. the chemical absorption method is useful. In this study. the kinetics of the reaction between $CO_2$ and the sterically hindered amine solution with piperazine. have been investigated from measurements of the rate of absorption of $CO_2$ in the stirred vessel that has a horizontal liquid-gas interface, in the temperature range $30{\sim}70^{\circ}C$. The experiments were carried out in the range 10.130~20.260 kPa of partial pressure of $CO_2$, and in aqueous $2.0kmol/m^3$ AMP solution with $0{\sim}0.4kmol/m^3$ piperazine The experimental results are as follows: 1) The absorption rate of $CO_2$ into aqueous AMP + piperazine solution is gett ng faster than that of aqueous AMP absorbents with temperature. Because the activation energy of piperazine 57.147 kJ/mol is higher than that of AMP 41.7kJ/mol. therefore the effect of piperazine on absorption rate increases with temperature. 2) Compared with aqueous AMP solution. the absorption rate of $CO_2$ into AMP + piperazine solution increases from 6.33% at $30^{\circ}C$ to 12% at $70^{\circ}C$, so AMP + piperazine solution is thought to be a better than AMP solution, 3) The reaction rate constants of piprazine in aqueous AMP solution with $CO_2$ have been determined as 217.21, 420.46, 707.00 and $3162.167m^3/kmol{\cdot}s$ respectively at 30, 40, 50 and $70^{\circ}C$ but these results are higher than those of Xu which were 186.7. 367.32. 693.01. $2207.65m^3/kmol{\cdot}s$ at 30, 40, 55, $70^{\circ}C$in aqueous MDEA solution. So the regression analysis of the data has led to the following equation In $k_p$ =28.324-6934.7/T.