• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.1087-1094
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• 2014

An numerical technique of impedance boundary condition to improve an efficiency in the process of moment method with CFIE(Combined Field Integral Equation), which is widely used to analyze the scattering property of dielectric scatterers, and results of its cross-validations are presented in this study. Application of the impedance boundary allows to represent the equivalent surface currents of dielectric scatterer depicted by both kinds of electric/magnetic surface currents(Js, Ms) to the single surface current by Js or Ms only. Accuracy of this technique is validated by the existing CFIE and theoretical values such as Mie-series solution and small perturbation scattering model. The computational difference of less than 1 dB was verified within an imaginary part of dielectric constant more than 12, as well.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.117-128
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• 2018

In this paper, compact linear dual polarized series-fed $1{\times}2$ linear and $2{\times}2$ planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and $50-{\Omega}$ matched transformer. Matching between a radiating patch and the $50-{\Omega}$ microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (${\lambda}/4$ impedance transformer) placed at both horizontal and vertical planes, in the case of the $2{\times}2$ planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are $1.9305{\times}0.9652{\times}0.05106{{\lambda}_0}^3$ and $1.9305{\times}1.9305{\times}0.05106{{\lambda}_0}^3$, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient ($S_{11}$) results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth >140 MHz (9.56-9.72 GHz) defined by $S_{11}$<-10 dB with 1.43%, and $S_{21}$<-25 dB in the case of prototype-2 (9.58-9.74 GHz, $S_{11}$< -10 dB) >140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol), gain, efficiency, front-to-back ratio, half-power beam width) at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications.

• Journal of Intelligence and Information Systems
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• v.8 no.2
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• pp.91-103
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• 2002

A collaborative filtering which supports personalized services of users has been common use in existing web sites for increasing the satisfaction of users. A collaborative filtering is demanded that items are estimated more than specified number. Besides, it tends to ignore information of other users as recommending them on the basis of information of partial users who have similar inclination. However, there are valuable hidden information into other users' one. In this paper, we use Association Rule, which is common wide use in Data Mining, with collaborative filtering for the purpose of discovering those information. In addition, this paper proved that Association Rule applied to Recommender System has a effects to recommend users by the relation between groups. In other words, Association Rule based on the history of all users is derived from. and the efficiency of Recommender System is improved by using Association Rule with collaborative filtering.

• Journal of Korean Society of Transportation
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• v.28 no.2
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• pp.21-32
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• 2010

A traffic island, typical channelization facilities, is widely applied to newly road designs and black spots improvement projects as traffic safety measures. However positive effects of a traffic island for traffic safety have not been reported specifically. Accordingly this study analyzed the accidents reduction effectiveness and economics of installing traffic islands under various roadways and traffic conditions. For this purpose normality test, paired t-test and Wilcoxon signed rank test were applied to this study based on traffic accidents, roadways and traffic environments data for 3 years before and after improvement at 54 intersections. The results showed that most of traffic accidents were reduced significantly after installing traffic islands except when traffic islands were installed in outside of cities and farming regions where use efficiency is low, curve sections with poor visibility, poor alignment sections with acceleration/deceleration lanes, road sections where occurs conflicts frequently due to did not install of acceleration/deceleration lanes, and road sections where cross with single lane road.

• Journal of Korean Clinical Nursing Research
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• v.26 no.1
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• pp.10-25
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• 2020

Purpose: The purpose of this study was to update the previously developed nursing practice guideline for enteral nutrition (EN). Methods: The guideline update was done in 22 steps using standardized methodology for nursing practice guidelines. Results: The updated EN guideline consisted of 16 domains and 228 recommendations. The domains and number of recommendations in each domain were for IDSA (Infectious Diseases Society of America): 8 on general instruction, 9 on general instruction for special nutrition, 9 on general instruction for EN, 3 on assessment of EN, 10 on access to EN, 18 on EN device insertion, 16 on selection and preparation of nutritional supplements, 46 on administration and stopping EN, 22 on maintenance and management of EN, 9 on monitoring EN, 16 on prevention and management of complications of EN, 18 on medication administration, 20 on EN in various situations, 20 on prevention of errors, 1 on nursing education, and 3 on nursing documentation. For the levels of evidence, there were 9.7% for level I, 13.1% for level II, 62.5% for level III and 1.1% for GRADE (Grading of Recommendations Assessment, Development and Evaluation): 3.3% for low, 0.8% for moderate, 9.3% for very low. A total of 133 recommendations were newly developed and 10 previous recommendations were modified. Conclusion: This updated EN nursing practice guideline can be used to enhance evidence-based practice in fundamentals of nursing practice and it should be disseminated to nurses nationwide in order to improve the efficiency of EN practice.

• Structural Engineering and Mechanics
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• v.8 no.2
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• pp.165-180
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• 1999

The cost effectiveness of using steel roof systems for residential buildings is becoming increasingly apparent with the decrease in manufacturing cost of steel components, reliability and efficiency in construction practices, and the economic and environmental concerns. While steel has been one of the primary materials for structural systems, it is only recently that its use for residential buildings is being explored. A comprehensive system for the design of residential steel roof truss systems is presented. In the first stage of the research the design curves obtained from the AISI-LRFD code for the manufactured cross-sections were verified experimentally. Components of the truss systems were tested in order to determine their member properties when subjected to axial force and bending moments. In addition, the experiments were simulated using finite element analysis to provide an additional source of verification. The second stage of the research involved the development of an integrated design approach that would automatically design a lowest cost roof truss given minimal input. A modified genetic algorithm was used to handle sizing, shape and topology variables in the design problem. The developed methodology was implemented in a software system for the purpose of designing the lowest cost truss that would meet the AISI code provisions and construction requirements given the input parameters. The third stage of the research involved full-scale testing of a typical residential steel roof designed using the developed software system. The full scale testing established the factor of safety while validating the analysis and design procedures. Evaluation of the test results indicates that designs using the present approach provide a structure with enough reserve strength to perform as predicted and are very economical.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.1-10
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• 2008

A transient 3-D numerical simulation was performed to analyze the fire safety in a railway tunnel equipped with a mechanical ventilation system. The behavior of pollutants was studied for the emergency operation mode of ventilation system in case of fire in the center of the rescue station and near the escape route. Various schemes of escape route construction for connection angle($45^{\circ}$, $90^{\circ}$, 135^{\circ}$) and slope($10^{\circ}$) were evaluated for the ventilation efficiency in the fire near the escape route. From the results, it was shown that the mode of the ventilation fan operation which pressurizes the tunnel not under the fire and ventilates the smoke from the tunnel under the fire is most effective for the smoke control in the tunnel in case of the fire occurrence. It was also shown that the blowing of jet fan from the rescue tunnel to the main tunnel should be in the same direction as the flow direction in the main tunnel arising from the traffic and the buoyancy.

• Journal of Korea Multimedia Society
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• v.24 no.10
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• pp.1449-1460
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• 2021

The visual design elements of packaging play an vital role in attracting consumers' attention, forming their sense of pleasure and sensory expectations, as well as having an important impact on the actual product experience. This study aims to explore whether the colors and textures in the packaging design elements of canned beer will affect consumers' senses, judgments and taste perception of canned beer. Participants in Survey I (N=193) evaluated their expectations for beer freshness, softness, bitterness and alcohol content by observing the packaging of canned beer, then recorded whether they could get the expected experience when tasting beer, and evaluated their preference and purchase intention. In the Survey II, 4 kind of colors and 2 types of texture shapes were applied, and all participants were provided with the same beer for multivariate cross contract analysis to evaluate the specific impact of color and texture of packaging design elements on consumers' taste and the interaction between sensory judgment and taste perception.The results showed that both colors and textures had a significant affect on the sensory expectation (pre-tasting score) of canned beer, but their effects on the sensory score after tasting (actual perception)were inobvious. The analysis of the influence of the interaction between color, texture and shape on taste perception shows that when the expected packaging appearance perception is similar to the actual drinking perception (i.e., straight line and B/G or arc line and Y/R), it is more likely to obtain consumers' favor and higher purchase intention evaluation than the inconsistent canned beer packaging (i.e., straight line and Y/R and arc line and B/G). This paper discusses the influence of these results on the packaging design of canned beer and the possibility of improving the brand efficiency by meeting the visual elements of packaging design expected by consumers.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.129-136
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• 2021

Radiation shields used in medical institutions mainly use lead to manufacture products and fitments. Although lead has excellent processability and economic efficiency, its use is being reduced due to environmental issues when it is disposed of. In addition, when used for a long time, there is a limit to using it as a shielding film, shielding wall, medical device parts, etc. due to cracking and sagging due to gravity. To solve this problem, copper, tin, etc. are used, but tungsten is mostly used because there is a difficulty in the manufacturing process to control the shielding performance. However, it is difficult to compare with other shielding materials because the characteristics according to the type of tungsten are not well presented. Therefore, in this study, a medical radiation shielding sheet was manufactured in the same process using pure tungsten, tungsten carbide, and tungsten oxide, and the particle composition and shielding performance of the sheet cross-section were compared.As a result of comparison, it was found that the shielding performance was excellent in the order of pure tungsten, tungsten carbide, and tungsten oxide.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.815-826
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• 2018

The intense drought affecting olive production in Northern Chile underscores the need to research non-traditional irrigation strategies to obtain the best crop performance. Accordingly, this study aimed to obtain preliminary data to guide future research on this topic. Different water replenishment levels on crop evapotranspiration ($ET_c$ ; 13.5, 27.0, 40.5, and 54%) were established in a young orchard, cv. Arbequina, from the end of fruit drop (EFD) to full bloom in the next season. We evaluated the influence of plant water status (${\Psi}_{stem}$ ) and crop load, considered as function of fruit number divided by trunk cross-sectional area, on reproductive and productive variables using multiple linear regressions. Our results show that crop load and ${\Psi}_{stem}$ measured from EFD to harvest affected yield components. Nevertheless, ${\Psi}_{stem}$ had the strongest influence on fruit size, pulp development, oil accumulation, and yield. Oil content and yield were reduced by 54% and 50% for each MPa, respectively, from ${\Psi}_{stem\;EFD-H}$ -1.8 MPa, an effect that intensified as crop load increased. During the period of flower development (September-November), the number of flowers per inflorescence and percentage of perfect flowers were reduced when ${\Psi}_{stem}$ was less than -2.0 MPa. These preliminary results showed that bud differentiation, inflorescence and flower formation are highly sensitive to water deficit.