• Title/Summary/Keyword: data modelling

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Current Status and Perspectives of Korean Geophysics (우리나라 지구물리학의 현황과 미래 전망)

  • Kwon, Byung-Doo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.12a
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    • pp.1-14
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    • 2007
  • This paper briefly reviews the history of the Korean geophysics and analyze the current status of geophysical researches. And the future prospects of geophysics are discussed based on social demands for the science and technology in Korea. About thirty universities offer geophysics courses in their academic curricula. Although the number of Ph.D. graduates in geophysics had been small until the year of 1990, but is rapidly increasing. In recent years about $7{\sim}8$ Ph.D's are produced every year. The major geophysical methods used in Ph.D. theses are seismic, electrical and electromagnetic methods, and earthquake waves and research themes are computational geophysics, which involve data processing, modelling, inversion and tomography, geological structures, and paleomagnetic studies in the order of numbers. The Solid Earth Geophysics is generally distinguished in two categories such as "Global Geophysics" and "Exploration Geophysics". However, they are intimately connected, and overlap in many sectors, especially in large scale research projects. The global geophysics has a more academic and general scientific meaning, and several research groups in Korean universities are carrying out the earthquake seismology and paleomagnetic studies. On the other hand the exploration geophysics focuses on practical application of geophysical concepts, and the public research institutes conduct large projects for exploration of energy and mineral resources and to cope with environmental and natural disaster problems. The geophysical studies for local geology and regional crustal structure utilize various survey methods and usually cover both academic and exploration purposes. The computational geophysics constitutes the indispensable theoretical backgrounds for all geophysical sectors. Many young Korean geophysicists, who have strong background in mathematics and physics, devote to the computational geophysics and several groups have made the internationally highest level achievements. But, Korean geophysicists have to expand their research interests to include more global-scale, high-tech researches and collaborative works with various other science groups.

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Humidification Characterization of water-to-gas Membrane Humidifier for Polymer Electrolyte Membrane Fuel Cell (고분자 전해질 연료전지용 water-to-gas 막 가습기의 투과 특성)

  • Chang, Dae-Kwon;Lee, Yong-Taek
    • Membrane Journal
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    • v.20 no.4
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    • pp.326-334
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    • 2010
  • In this study, characterization and performance of membrane humidifier using membrane distillation was evaluated for moisture of fuel gas in the PEMFC. The data were expressed dew point. The best results show $51.19^{\circ}C$ at $60^{\circ}C$ of water temperature, $54.22^{\circ}C$ at 900 mL/min and $60.03^{\circ}C$ at 100 strands. The mass transfer modelling of membrane humidifier were able to predict humidification of fuel gases for operating PEMFC. When the membrane humidifier was applied to the 100 W stack, it showed stable voltage and power. The volume of membrane humidifier was small however, showed better performance than bubble humidifier.

Validating the Entrepreneurial Intention Model on the University Students in Saudi Arabia

  • HODA, Najmul;AHMAD, Naim;AHMAD, Mobin;KINSARA, Abdullah;MUSHTAQ, Afnan T.;HAKEEM, Mohammad;AL-HAKAMI, Mwafaq
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.11
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    • pp.469-477
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    • 2020
  • The main objective of this paper is to examine the applicability of Linan and Chen's entrepreneurial intention model (EIM) in predicting the entrepreneurial intention. EIM is an adaptation of the Theory of Planned Behavior that focuses on entrepreneurial intention and hypothesizing slightly different patterns of relationship with regards to subjective norms. The model also includes human capital and demographic factors. Snowball sampling method was used to collect data using the entrepreneurial intention questionnaire (EIQ) through several social media platforms. The survey indicates that the overall entrepreneurial intention of Saudi students is high (mean = 5.41). Eight out of the seventeen hypothesized relationships were found to be significant. Among the demographic variables, gender-personal attitude was significant whereas self employment experience and years of business education were found to be significantly related with perceived behavioral control. The statistical analysis using partial least square structural equation modelling validated the model. All the three antecedents of entrepreneurial intention were significantly related with entrepreneurial intention. The results of this study will help policy makers to get deep understanding into the phenomenon of entrepreneurship among Saudi university students and thereby develop a conducive environment. This study also validates the entrepreneurial intention model in a different cultural context.

Dendropanax morbifera and Rubus coreanus Miq. Extracts Inhibits the Formation of Uric Acid Crystal by Reducing Xanthine Oxidase Activity

  • Hurh, Joon;Simu, Shakina Yesmin;Han, Yaxi;Ahn, Jong-Chan;Yang, Deok-Chun
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2018.04a
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    • pp.95-95
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    • 2018
  • Uric acid is the end product of purine metabolism in human body, originating from hypoxanthine after enzyme catalysis by Xanthine oxidase (XOD). Hyperuricemia results as a result of either over-generation of uric acid or a reduction in its excretion. In silico modelling methods such as Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) prediction, Autodock 4.2.6 program were used to study the potential inhibitory compounds of XOD. Also we investigated the inhibition of XOD activity by using the extracts of Dendropanax morbifera and Rubus coreanus Miq spectrophotometrically. According to ADMET data, several compounds from D. morbifera and R. coreanus plants, were found to be more potent in inhibiting the XOD activity than allopurinol. XOD inhibitory activity is evaluated by quantifying the formation of uric acid by measuring the absorbance at 290 m ($A_{290}$).D. morbifera extract inhibited XOD activity at $250{\mu}g/ml$, however the extracts from R. coreanus has inhibited XOD activity at $25{\mu}g/ml$. The major compound of R. coreanus, ellagic acid significantly increased the inhibition rate from $9{\mu}g/ml$ and showed a 71% suppression rate at $15{\mu}g/ml$. Finally, these results suggested a potential inhibitory activities of the extracts from D. morbifera and R. coreanus Miq, but further research is needed to validate to ensure their safe usage as drug.

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Design of a Waveguide Broad-wall Longitudinal Slot Array Antenna of X-type Monopulse Axes (X-형 모노펄스 축구조를 가지는 도파관 광벽 종방향 슬롯 배열 안테나의 설계)

  • 나형기;박창현
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.208-216
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    • 2002
  • In this paper, the design method of a waveguide broad-wall longitudinal slot array monopulse antenna of X-type monopulse axes is presented, and the method is verified through manufacture and measurement. In the antenna design of this paper, the antenna size is small and the monopulse axes are X-type. Thus, the common continuous aperture distribution fuction is not suitable and the power balance among antenna quadrants should be considered. Also, since the waveguide height is reduced into 0.1 wavelength, the modelling of the slot characteristics is not simple. Thus, in this paper, the aperture distribution is optimized by using random number, and the balance among the quadrants is achieved by applying the quadrant weighting factor during the aperture optimization process. Also, the moment method procedure is accelerated by applying the interpolation technique to some part of the moment matrix, and the moment method procedure is added to the array synthesis program as a subroutine so that the slot characteristics can be calculated directly when it is required. Based on this method, a antenna of 28dBi is designed and manufactured. It is found that the antenna characteristics is similar to design data.

A Study on the Relationships among Intrinsic Motivators, Psychological Empowerment, Affective Commitment and Service Quality (내재적 동기요인, 심리적 임파워먼트, 정감적 몰입 및 서비스품질 간 관계에 관한 연구 -호텔종사자를 중심으로-)

  • Choi, Young-Sook;Kim, Sun-Bae
    • Journal of Digital Convergence
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    • v.11 no.7
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    • pp.111-122
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    • 2013
  • The purpose of this study was to investigate the relationships among intrinsic motivators, psychological empowerment, affective commitment, and service quality among hotel industry employees. For this study, data were collected from 233 hotel employees in Seoul Metropolitan City with self-administered questionnaires and analyzed using structural equation modelling technique. This study found that two job characteristics variables(job challenge and job autonomy) had positive effects on hotel employees' psychological empowerment; that three job characteristics variables(job challenge, job variety and job autonomy) and psychological empowerment had positive effects on hotel employees' organizational commitment; and that psychological empowerment and organizational commitment had positive effects on hotel employees' service quality.

The Effects of Core Competencies on the Management Performance of Hospitals : With a Focus on the Mediating Roles of Medical Service Orientation and Internal Customer Orientation (의료기관 핵심역량과 경영성과의 구조적 인과관계 분석 : 의료서비스 지향성과 내부고객 지향성)

  • Kim, In Yong;Lee, Sang Hyeok
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.3
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    • pp.107-117
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    • 2014
  • The Purpose of this study was to empirically investigate the effects of core competencies on the management performance of hospitals and the mediating roles of medical service orientation and internal customer orientation. The sample of this study was composed of 307 employees from 18 general hospitals in Incheon Metropolitan City and Bucheon City. Data were collected with self-administered questionnaires and analyzed using structural equation modelling technique. This study found that core competencies had positive effects on the management performance of hospitals and that medical service orientation and internal customer orientation mediated the relationship between core competencies and the management performance of hospitals. The theoretical and practical implications of the results were discussed and the directions for future research were suggested.

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The Effect of Consumer Global-Mindedness and Global Fashion Brand Out-Of-Home Advertising on Brand Evaluation (소비자의 글로벌 마인드와 글로벌 패션 브랜드의 옥외 광고에 대한 호의도가 브랜드 평가에 미치는 영향)

  • Kim, Ah Young;Hwang, Sun Jun
    • Journal of the Korean Society of Costume
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    • v.67 no.2
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    • pp.1-16
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    • 2017
  • This study was conducted to investigate how consumer global-mindedness affects global fashion out-of-home (OOH) advertising which global consumer culture positioning applies, and to examine the relations among global fashion brand OOH advertising, perceived fashion brand globalness, perceived quality and brand reputation. Data were collected from 238 general people in 20~30s in seoul and were analyzed by using statistic methods such as frequency analysis, reliability analysis, confirmatory factor analysis and structural d modelling by running both SPSS 18.0 and AMOS 7.0 program. The results of this study were as follows. First of all, it indicated that the fit indexes were satisfied and the overall model of this study showed a favorable goodness of it from the results of confirmatory analysis. Secondly, consumer global-mindedness had a positive impact on preference towards global fashion OOH advertising. Finally, preference towards global fashion brand OOH advertising positively affected perceived fashion brand globalness, perceived quality and fashion brand reputation. The results implies that it is necessary that fashion brands fully understand consumers' tendency and the benefits of marketing can be maximized through global positioning OOH advertising on subways which makes consumers recognize fashion brands as global ones.

Export Behaviors of the Passenger Cars of Gunsan, Pyeongtaek and Ulsan Port (항만별 승용차 수출 행태: 군산항.평택항.울산항)

  • Mo, Soo-Won
    • Journal of Korea Port Economic Association
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    • v.27 no.2
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    • pp.27-38
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    • 2011
  • The paper aims at examining the behavioral characteristics of the passenger car export of Gunsan, Pyeongtaek, and Ulsan port. This is accomplished by modelling export demand as exchange rate and the Unites States industrial production. All series span the period January 2001 to December 2010. I first show that both the series and the residuals are stationary at the 5 percent significance level. The result cannot reject the null hypothesis of a unit root in each of the level variables and of a unit root for the residuals from the cointegration regression at the 5 percent significance level. I hitherto make use of forecast error decomposition and historical decompositions The forecast error decomposition indicates that car export is endogenous to industrial production and exchange rate. The historical decompositions for the export show that the entire difference between actual export and the base forecast can be attributed to industrial production shocks since exchange rate moves closer to the actual data or the base forecast. It indicates that industrial production outperforms exchange rate in explaining the passenger car exports.

TCC behavior of a shell phase in core/shell structure formed in Y-doped BaTiO3: an individual observation (Yttrium이 첨가된 BaTiO3에서 형성된 core/shell 구조에서 shell의 TCC 거동: 독립적 관찰)

  • Jeon, Sang-Chae
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.30 no.3
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    • pp.110-116
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    • 2020
  • Grains in the BaTiO3, which is used for a dielectric layer in MLCC(Multi-Layer Ceramic Capacitor) are necessary to form core/shell structure for a stable TCC(Temperature Coefficient of Capacitance) behavior. The shell property has been deduced from the whole TCC behavior of core/shell structure due to its tiny size, ~ few ㎛. This study demonstrates the individual TCC behavior of the shell phase measured by micro-contact measurement in a temperature range between 35 and 135℃. Pt electrode pairs deposited on an enlarged core/shell structure in a diffusion couple sample made the measurement possible. As a result, the DPT (Diffusion Phase Transition) behavior of the shell phase was revealed as a different TCC behavior from that of the core: a broad peak with Tm at 65℃. This would be also useful experimental data for a modelling that depicts dielectric-temperature behavior of core/shell structure.