• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.12-23
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• 2003

The expansion of internet and the development of communication technology have brought about an explosive increasement of data. Further progress has led to the increasing demand for efficient and effective data analysis tools. According to this demand, data mining techniques have been developed to find out knowledge from a huge amounts of raw data. This paper suggests a generalization based classification method which explores rules from real world data appearing repeatedly. Also, it analyzed the relation between weather data and forest fire, and efficiently predicted through it as a prediction model by applying the suggested generalization based classification method to forest fire data. Additionally, the proposed method can be utilized variously in the important field of real life like the analysis and prediction on natural disaster occurring repeatedly, the prediction of energy demand and so forth.

• Steel and Composite Structures
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• v.34 no.4
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• pp.511-524
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• 2020

In this research, a simple four-variable trigonometric integral shear deformation model is proposed for the static behavior of advanced functionally graded (AFG) ceramic-metal plates supported by a two-parameter elastic foundation and subjected to a nonlinear hygro-thermo-mechanical load. The elastic properties, including both the thermal expansion and moisture coefficients of the plate, are also supposed to be varied within thickness direction by following a power law distribution in terms of volume fractions of the components of the material. The interest of the current theory is seen in its kinematics that use only four independent unknowns, while first-order plate theory and other higher-order plate theories require at least five unknowns. The "in-plane displacement field" of the proposed theory utilizes cosine functions in terms of thickness coordinates to calculate out-of-plane shear deformations. The vertical displacement includes flexural and shear components. The elastic foundation is introduced in mathematical modeling as a two-parameter Winkler-Pasternak foundation. The virtual displacement principle is applied to obtain the basic equations and a Navier solution technique is used to determine an analytical solution. The numerical results predicted by the proposed formulation are compared with results already published in the literature to demonstrate the accuracy and efficiency of the proposed theory. The influences of "moisture concentration", temperature, stiffness of foundation, shear deformation, geometric ratios and volume fraction variation on the mechanical behavior of AFG plates are examined and discussed in detail.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.3
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• pp.169-176
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• 2004

The Mechanistic model, considering expansion stress, coefficient of diffusion etc. to time, is applied to predict the deterioration of concrete structures of the nuclear power plant(NPP) due to sulfate attack. Mix design for the test was three kinds of specified compressive strength 385, 280 and $210kgf/cm^2$ which are used to construct NPPs and cement was type I and V. The immersion test was performed with 10% $Na_2SO_4$ solution to cement type and strength for a year. The coefficient of diffusion on each concrete mix is calculated based on the results of immersion test, and it is used for predicting the sulfate attack of the concrete structures of NPP. The coefficient of diffusion of the target concrete ranged $0.5763{\sim}3.9002{\times}10^{-12}m^2/sec.$, and the sulfate attack rate of concrete structures of the NPP was predicted as 0.1~7.1 mm/year.

• Advances in nano research
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• v.16 no.2
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• pp.111-125
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• 2024

Recently, a lot of research has been done on the analysis of axial vibrations of homogeneous and FG nanotubes (nanorods) with various aspects of vibrations that have been fully mentioned in history. However, there is a lack of investigation of the dynamic internal resonances of FG nanotubes (nanorods) between them. This is one of the essential or substantial characteristics of nonlinear vibration systems that have many applications in various fields of engineering (making actuators, sensors, etc.) and medicine (improving the course of diseases such as cancers, etc.). For this reason, in this study, for the first time, the dynamic internal resonances of FG nanorods in the simultaneous presence of large-amplitude size dependent behaviour, inertial and shear effects are investigated for general state in detail. Such theoretical patterns permit as to carry out various numerical experiments, which is the key point in the expansion of advanced nano-devices in different sciences. This research presents an AFG novel nano resonator model based on the axial vibration of the elastic nanorod system in terms of derivation from large-amplitude size dependent internal modals interactions. The Hamilton's Principle is applied to achieve the basic equations in movement and boundary conditions, and a harmonic deferential quadrature method, and a multiple scale solution technique are employed to determine a semi-analytical solution. The interest of the current solution is seen in its specific procedure that useful for deriving general relationships of internal resonances of FG nanorods. The numerical results predicted by the presented formulation are compared with results already published in the literature to indicate the precision and efficiency of the used theory and method. The influences of gradient index, aspect ratio of FG nanorod, mode number, nonlinear effects, and nonlocal effects variations on the mechanical behavior of FG nanorods are examined and discussed in detail. Also, the inertial and shear traces on the formations of internal resonances of FG nanorods are studied, simultaneously. The obtained valid results of this research can be useful and practical as input data of experimental works and construction of devices related to axial vibrations of FG nanorods.

• Journal of Climate Change Research
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• v.3 no.3
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• pp.183-193
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• 2012

In this study, the S University's energy usage, greenhouse gas emissions situation and potential reduction amount were analyzed using a long-term energy analysis model, LEAP. In accordance with the VISION 2020 and university's own improvement plans, S University plans to complete a second campus through expansion constructions by 2020 and by allocating the needed land. Accordingly, increases in energy usage and greenhouse gas emissions seem inevitable. Hence, in this study, the calculations of potential reduction amount by 2020 were attempted through the use of LEAP model by categorizing the energy used based on usage types and by proposing usage typebased reduction methods. There were a total of 4 scenarios: a standard scenario that predicted the energy usage without any additional energy reduction activity; energy reduction scenario using LED light replacement; energy reduction scenario using high efficiency building equipment; and a scenario that combines these two energy reduction scenarios. As scenario-based results, it was ascertained that, through the scenario that had two other energy reduction scenarios combined, the 2020 greenhouse gas emissions amount would be 14,916 tons of $CO_2eq$, an increase of 43.7% compared to the 2010 greenhouse gas emissions amount. Put differently, it was possible to derive a result of about 23.7% reduction of the greenhouse gas emissions amount for S University's greenhouse gas emissions amount through energy reduction activities. In terms of energy reduction methods, changing into ultra-high efficiency building equipment would deliver the most amount of reduction.

• Korean Journal of Optics and Photonics
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• v.29 no.4
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• pp.166-172
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• 2018

In this paper, we propose a new method to predict a mirror's surface deformation due to the stress of moisture release by a coating in the environment of outer space. We measured the surface deformation of circular samples 50 mm in diameter and 1.03 mm thick, using an interferometer. The results were analyzed using Zernike fringe polynomials. The coating stress caused by moisture release was calculated to be 152.7 MPa. This value was applied to an analytic model of a 1.25 mm thickness sample mirror, confirming that the change of surface deformation could be predicted within the standard deviation of the measurement result ($78.9{\pm}5.9nm$). Using this methodology, we predicted the surface deformation of 600 mm hyperbolic mirror for the Compact Advanced Satellite, which will be launched in 2019. The result is only $2.005{\mu}m$ of focal shift, leading to 2.3% degradation of modulation transfer function (MTF) at the Nyquist frequency, which satisfies the requirement.

• Journal of Distribution Science
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• v.15 no.5
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• pp.53-64
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• 2017

Purpose - This study focuses on use intention of mobile travel Apps by Chinese tourists visiting Korea based on UTAUT model, ISS model and ITM model. And the corresponding market promotion schemes are proposed for operators of mobile travel Apps by the research results. Research design, data, and methodology - After collecting 326 respondents in China with cross-sectional questionnaires, this study begins the empirical research with users of mobile travel Apps, and analyzes data with IBM SPSS 23.0 and IBM AMOS 23.0. Results - The results of this study include the following aspects: firstly, the System quality and Information quality are accepted for hypotheses of Satisfaction and Performance expectancy. Secondly, the Personal Propensity to Trust and Firm Reputation are accepted for Initial Trust hypothesis, and the hypotheses of Firm Reputation and Initial Trust are accepted for Use Intention. Thirdly, the Performance expectancy, Effort expectancy, Social influence are accepted for Use Intention hypothesis. Conclusions - With the increase of tourists visiting Korea, it can be predicted that the needs visiting Korea will be increased persistently for Chinese - this trend brings about the increase of the Chinese travel. First, information quality greatly influences satisfaction and performance expectancy. The research result shows that, the higher the mobile traveling App's information quality is, the higher the satisfaction and performance expectancy will be. Therefore, operators of mobile traveling App should have in-depth investigations towards users, to know the latter's real demand to the information quality and then provide corresponding services. Second, performance expectancy and effort expectancy greatly influence users' intention. Therefore, mobile traveling App operators should improve Apps' convenience and efficiency and, in doing so, find an effective method for market expansion. Third, social influence greatly affects users' intention. The result shows that mobile traveling App operators should pay attention to the influence of mass media and friends' recommendation on users, thereby it is necessary to improve advertisement activities. Fourth, initial trust also influences users' intention. The result shows that initial trust is a key element inducing users to generate use intention. Therefore, mobile traveling Apps operators should make efforts to catch elements that influence users' initial trust.

• Journal of Korea Water Resources Association
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• v.53 no.2
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• pp.131-140
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• 2020

The purpose of this study is to analyze the possibility of future droughts by calculating the Standardized Groundwater level Index(SGI) after predicting groundwater level using Long Short Term Memory (LSTM) model. The groundwater level of the Kumho River basin was predicted for the next three years by using the LSTM model, and it was validated through RMSE after learning with observation data except the last three years. The temporal SGI was calculated by using the prediction data and the observation data. The calculated SGI was interpolated within the study area, and the spatial SGI was calculated as the average value for each catchment using the interpolated SGI. The possibility of spatio-temporal drought was analyzed using calculated spatio-temporal SGI. It is confirmed that there is a spatio-temporal difference in the possibility of drought. Through the improvement of deep learning model and diversification of validation method, it is expected to obtain more reliable prediction results and the expansion of study area can be used to respond to drought nationwide, and furthermore it can provide important information for future water resource management.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.892-899
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• 2002

Among the methods for enhancement of load-carrying capacity on flexural concrete member, recently, a concept is being investigated which replaces the steel in a conventional reinforced concrete member with a fiber reinforced polymer(FRP) shell. This study focuses on modeling of the structural behavior of concrete surrounded with FRP shells in flexural bending members. A numerical model of fiber cross-sectional analysis is proposed to predict the stress and deformation state of the FRP shell and concrete. The stress-strain relationship of concrete confined by a FRP shell is formulated to be based on the constitutive law of concrete in multi-axial compressive stress state, in assuming that the compression response is dependent on the radial expansion of the concrete. To describe the FRP shell behavior, equivalent orthotropic properties of in-plane behavior from classical lamination theory are used. The present model is validated to compare with the experiments of 4-point bending tests of FRP shell concrete beam, and has well predicted the moment-curvature relationships of the members, axial and hoop strains in the section, and the enhancement of confinement effect in concrete surrounded by FRP shell.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.501-511
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• 2016

Predicting potential spatial distribution of Monochamus alternatus, a major insect vector of the pine wilt disease, is essential to the spread of the pine wilt disease. The purpose of this study was to predict future domestic spatial distribution of M. alternatus by using the CLIMEX model considering the temperature condition of the vector's life history. To predict current distribution of M. alternatus, the administrative divisions data where the pine wilt spots caused by M. alternatus were found from 2006 to 2014 and the 10-year mean climate observed data in 68 meteorological stations from 2006 to 2015 were used. Eight parameter sets were chosen based on growth temperature range of M. alternatus reported in preceding researches. Error matrix method was utilized to select and simulate the parameter sets showing the highest correlation with the actual distribution. Regarding the future distribution of M. alternatus, two periods of 2050s(2046-2055) and 2090s(2091-2100) were predicted using the projected climate data of RCP 8.5 Scenario generated from Korea Meteorological Administration. Overall results of M. alternatus distribution simulation were fit in the actual distribution; however, overestimation in Seoul Metropolitan area and Chungnam Region were shown. Gradual expansion of M. alternatus would be expected to nationwide from western and southern coastal areas of Korea peninsula.