• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.115-118
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• 1988

Mating experiments were performed to, elucidate the distribution of perfect state of Microsporum gypseum complex originated from animals and soils in Korea. A total of 30 strains of M. gypseum complex, composed of 16 from animals and 14 from soils, ere mated with the tester strains of Nannizzia incurvata, N. gypsea and N. fulva. Among 30 strains of M. gypseum complex examined, 16 strains(53.3%) were N. incurvata, 13 strains(43.3%) N. gypsea and 1 strain (3.3%) N. fulva. Among 13 strains of dog isolates, 8 strains(61.5%) were N. incurvata and 5 strains(38.5%) N. gypsea. And each strain isolated from Korean native goat, monkey and albino rat was N. gypsea. Among 14 strains of soil isolates, 8 strains(57.2%) were N. incurvata, 5 strains (35.7%) N. gypsea and 1 strain(7.2%) N. fulva. And -mating type was more frequently observed than +mating type in the strains of N. incurvata and N. gypsea. By this study, N. fulva was isolated the first time in Korea.

• The Journal of Korean Academic Society of Nursing Education
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• v.19 no.3
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• pp.341-350
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• 2013

Purpose: This study was done to identify the relationship among ego resilience, the problem solving process and clinical competency in nursing students. Methods: Data were collected by questionnaires from 265 nursing students in D city. Measures were ego resilience, problem solving process and clinical competency. Data was analyzed using frequency analysis, t-test, one-way ANOVA, person's correlation coefficients, and multiple regression analysis with SPSS/WIN 19.0 version. Result: The Ego resilience score of subjects was 2.80 out of a perfect score of 4, the problem solving process score of subjects was 3.12, and the clinical competency score of subjects was 3.49 out of a perfect score of 5. There was a significant positive correlation among ego resilience, problem solving process and clinical competency. The significant predictors of problem solving process and clinical competency were ego resilience. Conclusion: These findings indicate that there is a need to increase ego resilience to improve the problem solving process and clinical competency of nursing students. The results should be reflected in the development of effective curricula.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.1
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• pp.44-52
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• 2014

In this study, the influence of the near field, far field and radiation directivity of microstrip patch antenna when is used mushroom EBG(Electromagnetic Band Gap) as ground is investigated. Using characteristic of dispersion diagram of mushroom EBG, we calculated forbidden band(2.36GHz-2.85GHz) given mushroom type EBG microstrip antenna(2.45GHz) having 2-layer EBG that is operating within forbidden band. In oder to conform performance enhancemen of antenna using EBG ground, we have compared with the antenna using PEC(Perfect Electric Conductor) ground. We could know about 2.74dB increment of the radiation directivity, because EBG can suppress surface wave that is generated at interfaces of the dielectrics-conductor.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.452-457
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• 2003

An add-on type output regulator is proposed in this paper. By an add-on controller we mean an additional controller which operates harmonically with a pre-designed one. The role of the add-on controller is to reject a sinusoidal disturbance of unknown magnitude and phase but with known frequency. Advantages of the proposed controller include that (1) it can be used only when the performance of disturbance rejection needs to be enhanced, (2) when it is turned on or off, unwanted transient can be avoided (i.e., bumpless transfer), (3) it is designed for perfect disturbance rejection not just for disturbance reduction, (4) ability for perfect rejection is preserved even with uncertain plant model. This design may be promising for optical disc drive (ODD) systems in which disc eccentricity results in a sinusoidal disturbance. For ODD systems, the sensitivity function obtained by the pre-designed controller, which may have been designed by the lead-lag, $H_{\infty}$, or DOB (disturbance observer) technique, does not change much with the add-on controller except at the frequency of the disturbance. Since the add-on controller does the job of rejecting major eccentricity disturbance, the gain of the pre-designed controller does not have to be too high.

• The Journal of the Acoustical Society of Korea
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• v.9 no.2
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• pp.25-33
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• 1990

An ultrasonic power measurement system in milliwatt range was constructed. The ultrasonic power can be determined by measuring the radiation pressure on a target using self-compensating microbalance. Measurement was performed using a perfect reflector and a perfect absorber. In order to check the feasibility of the system, the ultrasonic power for the two targets was measured. Also, the systematic measurement errors and the reproducibility were examined. The relative error between two targets is proved to be within 2%. Also when the ultrasonic power range is larger than 10mW, the standard deviation for repeated measurement becomes smaller than ${\pm}$2%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.49-54
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• 2013

WPM(Wavelet Packet Modulation) is multicarrier system which is suitable for high speed transmission. The main advantage of using the WPM system is the fact that the flexible system effectively can be realized by the combination of filter coefficient. On the other hand, the major problem of multicarrier system is known to be the high PAPR. In this paper we propose WPM system that has a minimum PAPR by using filter coefficient adjustment method. We first derive the filter coefficient equation and then select the coefficient that has a minimum PAPR. we conduct WPM system by using a selected coefficient and we demonstrate the system performance by using computer simulation.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.1
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• pp.18-28
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• 2006

Some issues which should be considered in an R&D project selection problem are as follows: First, quantitative analysis on the efficiencies of R&D projects is required to guarantee objective validity in the evaluation of the projects. For this reason, the methodology for selecting R&D projects should be based on mathematical models that perform quantitative analysis. Second, in general there are ordinal factors like Likert-scale in the data for evaluating R&D projects. Previous researches, however, couldn't suggest explicit methods incorporating these ordinal factors into models. Third, for the R&D project selection problems with limited resources like budget, it is necessary to decide the perfect ranking of the all projects. This paper develops a mathematical model that can be applicable to the problems of selecting R&D projects with the previous features. In this paper, we improve the original DEA model for evaluating efficiency to incorporate ordinal factors and suggest a new model which can decide the perfect ranking of all projects by merging the improved DEA model and AHP method. Furthermore a web-based R&D project selection system using the DEA/AHP model suggested in this paper is developed and illustrated.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.145-155
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• 2020

This study analyzes the degree of competition in the oil refinery market in Korea, which is considered an oligopoly market. The price of gasoline and diesel and the quantity of supply are used to identify the market competition. We also analyze whether the oil tax reduction policy has affected market competition. The competitiveness of the market was examined using monthly data from 2008 to 2019. Bresnahan-Lau method was employed to estimate the degree of competition in the oil refinery market, which is frequently used in the industrial studies. The analysis shows that the gasoline and diesel markets seem close to a perfect competitive market. Also, the tax cut has weakened market competition. In other words, the monopolistic power has increased in the market, so consumers have not benefit from the price cuts as much as tax cuts. Although the oil refinery market where four major companies are competing, the government's monitoring and price disclosure system help the market to be highly competitive as much as a perfect competition market. The tax cut, in the high oil price era, has a negative effect on the competition because of an information asymmetry about the price-setting process between suppliers and consumers.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.359.1-359.1
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• 2016

The electromagnetic (EM) properties of media, such as propagation, focusing and scattering, strongly rely on the electric permittivity and the magnetic permeability of media. Recently, artificially-created metamaterials (MMs) composed of periodically-arranged unit cells with tailored electric permittivity and magnetic permeability have drawn wide interest due to their capability of adjusting the EM response. MM absorbers using the conventional sandwich structures usually have very high absorption at a certain frequency, and the absorption properties of MMs can be adjusted simply by changing the geometrical parameters of unit cell. In this work, we suggested an incident-angle-independent broadband perfect absorber based on resistive layers. We analyze the absorption mechanism based on the impedance matching with the free space and the distribution of surface currents at specific frequencies. From the simulation, the absorption was expected to be higher than 96% in 1.4-6.0 GHz. The corresponding experimental absorption was found to be higher than 96% in 1.4-4.0 GHz, and the absorption turned out to be slightly lower than 96% in 4.0-6.0 GHz owing to the irregularity in the thickness of resistive layers.

• Journal of Information Technology Services
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• v.15 no.3
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• pp.247-263
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• 2016

The purpose of the study is to derive success factors of B2C reverse auction business model, a business model contributes to the recent innovative practices in e-commerce and service sector. Electronic reverse auction has been traditionally used to ensure the procurement convenience and purchasing efficiency in B2B or B2G settings, however, e-RA is now expanding its basis toward B2C commerce industry along the huge success of an online e-RA travel service provider Priceline.com. Recently, B2C e-RA business model is getting the spotlight in the Korean venture industry with a variety of startups in diverse areas. However, e-RA does not work perfect in all kinds of trade settings. Therefore, we conducted a multiple case study to find out the success factors of B2C business model as follows : First, large supplier basis is an important factor that constructs a quasi-perfect competition environment. Second, the high online and mobile accessibility or e-readiness of Korean consumers was also a critical aspect of the success of e-RA. Lastly, e-RA performs best when the supplier switching cost is low and the trading occurs infrequently.