• Journal of Korean Library and Information Science Society
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• v.48 no.4
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• pp.181-207
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• 2017

The purpose of this paper is to provide values and effectiveness to libraries making a new social network service marketing model and strategy. According to study, when libraries entice library users with social network services, the users become loyal customers who give libraries long-term supports. For method of study, it establishes 15 hypotheses and proves those hypotheses with 157 responders. After inspecting hypotheses, 13 hypotheses are adopted and 3 hypotheses are dismissed. During the research, it is verified that usefulness perceived by library users is the most important factor of user satisfaction and continuous use intention which increased library users' intention to continue visiting the library. In addition, effectivness of marketing and cause are found in order of system quality, information quality, reliability, interactivity, subjective norms. In other words, the study found that library users found their information for using social network services and this attribute affects user satisfaction and ultimately continuous use intention in a positive way.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.157-167
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• 2020

With the recent advancement of computer hardware and the contribution of open source libraries to facilitate access to artificial intelligence technology, the use of machine learning (ML) and deep learning (DL) technologies in various fields of exploration geophysics has increased. In addition, ML researchers have developed complex algorithms to improve the inference accuracy of various tasks such as image, video, voice, and natural language processing, and now they are expanding their interests into the field of automatic machine learning (AutoML). AutoML can be divided into three areas: feature engineering, architecture search, and hyperparameter search. Among them, this paper focuses on hyperparamter search with Bayesian optimization, and applies it to the problem of facies classification using seismic data and well logs. The effectiveness of the Bayesian optimization technique has been demonstrated using Vincent field data by comparing with the results of the random search technique.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.137-147
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• 2018

The purpose of this study was to examine the influence of variables of TAM, user characteristics variables, and perceived risk variables on the intention to use mobile payment. Through the combination of characteristics of mobile payment, this study also investigated the effect of various independent variables on the intention to use mobile payment including the moderating effect of self-construal. To verify hypotheses of this study, the hierarchical regression analysis based on responses from 188 undergraduate and graduate students was conducted. The significant findings of this study were as follows: TAM variables, user characteristics variables and perceived risk variables had positive influence on the intention to use mobile payment. Self-construal was found to moderate the effect of the perceived usefulness, perceived ease of use and subjective norm. This study may provide important implications for both academicians and practitioners.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1325-1333
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• 2011

An analytical, numerical, and experimental comparison of the hydraulic and thermal performance of new vascular channels with semicircular cross sections was conducted. The following conditions were employed in the study: Reynolds number, 30-2000; cooling channels with a volume fraction of the cooling channels, 0.04; and pressure drop, $30-10^5$ Pa. Three flow configurations were considered: first, second, and third constructal structures with diameters optimized for hydraulic operations. To validate the proposed vascular designs by an analytical approach, 3-D numerical analysis was performed. The numerical model was also validated by the experimental data, and the comparison results were in excellent agreement in all cases. The validation study against the experimental data showed that compared to traditional channels, the optimized structure of the cooling plates could significantly enhance heat transfer and decrease pumping power.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.255-262
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• 2012

Numerical simulations were performed to evaluate the dispersion characteristics of the pollutant around a Wolsung coastal area at located nuclear power plants. Numerical experiments by using EFDC(Environmental Fluid Dynamics Code) showed good agreements by comparison with the time series and harmonic analysis of the tidal elevations. The released pollutants moved in north direction at flood tide and in south direction at ebb tide. The calculated salinity and temperatures showed good agreements with the observed results by NFRDI(National Fisheries Research & Development Institute). The water circulation due to the variations of the temperature, salinity and tidal components were analyzed to estimate the dispersion characteristics of the pollutant.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.723-728
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• 2011

Since the performance of a vacuum circuit breaker (VCB) mainly depends on the spring operating mechanism, an analysis of the spring operating mechanism is required in order to improve the design of a VCB. In this study, the static stiffness of the spring was determined by using a material testing machine, and the test results were used to model the spring through computer simulation. The multi-body dynamic model of the spring was established by using the RecurDyn program. The dynamic model was verified by comparing the results of stem displacements and rotating angles of the brake shaft obtained from the simulation and from the experiments. After verification of the dynamic model of VCB, the cam profile of the VCB was optimized through multi-body dynamics simulation in order to improve the performance of the closing mechanism.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.194-194
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• 2012

본 연구에서는 자연하천에서 Rhodamine-WT를 이용하여 추적자 실험을 수행하고 이를 바탕으로 오염사고대응예측모델에 대한 검증을 실시하고자 하였다. 최근 국내에서는 다양한 형태와 규모의 수질오염사고가 매년 수십건 이상 발생하고 있으며, 따라서 수치모형 기반의 수질오염 사고 대응 예측시스템에 대한 높은 신뢰성이 요구되고 있다. 수질사고에 노출되어 있는 지표수를 각종 용수로서 안전하게 공급하기 위해서는 정확한 수질예측이 필수적이며, 이를 위해서 수십 년간 연구되어 온 수질모델을 오염사고 대응예측시스템에 적합하도록 정확성과 신뢰성을 갖추기 위한 연구가 진행되어야 한다. 수치 모형을 이용한 물질의 이송 및 확산 모의에서는 오염물질 도달시간과 확산 농도를 결정하는 것이 가장 중요한 요소이므로 이송 및 확산 모의에 대한 검증 기법 개발 및 적용이 필요하다. 본 연구에서는 낙동강수계 지류하천인 감천에서 추적자 실험을 4회 실시하여 측정한 수리량과 농도 실측치를 이용하여 분산계수를 종 횡분산계수 산정이 가능한 2차원 유관추적법을 적용하여 산정하였다. 각 단면에 유속은 ADV-3차원 유속계인 Flow-Tracker를 사용하여 도섭으로 측정하였으며 하천의 흐름 방향의 직각으로 측선을 설치하고 펌프를 이용하여 채수를 한 다음 Rhodamie WT의 농도를 측정하였으며 측선의 위치 보정은 GPS를 통하여 보정하였다. 측정 자료를 이용하여 2차원 유관추적법으로 분산계수를 산정한 결과 각각의 측선에 따라서 다소 차이가 발생하였으며, 일부 구간에서는 이론식으로 계산한 분산계수와 근사한 값이 나타났다. 이는 사주가 매우 발달하고 만곡이 많은 실험구간의 특성상 Elder와 Fischer 식으로 계산한 값과 차이가 발생할 가능성이 높은 구간이기 때문인 것으로 판단된다. 또한 하폭에 대한 수심비가 커질수록 분산계수도 증가하고 평균유속에 대한 전단유속에 비에 비례하는 것으로 나타났다.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.561-570
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• 2009

In order to manage repair and maintenance efficiently in the mobile environment, the system structure to manage service as a policy and the policy description language are needed. This research defined the structure of PEP, which is the executioner of policy in the IETF policy framework, and proposed the policy description language which can be carried out under the PEP structure. The proposed policy description language derived demand matters based on documentary data and the characteristics of mobile and the policy information model was designed with the three stage approaches and was defined as policy description language. The three stage approaches are made up of the policy domain that decides the scope to which the policy applies, the policy rules which distinguish the kinds of policy application and control, and policy grammar which contextualizes the policy structure. In order to verify the efficiency of the policy description language, scenarios are defined with the policy description language and verified it by using policy tool and proved the expansive nature by comparing and analyzing other policy description language.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.2
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• pp.62-67
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• 2010

Swells occurred on the coast of the East Sea on February 24, 2008 caused a loss of three lives and also damaged several west coasts of Japan. The recent increase of swell intensity with number of accidents demands more accurate forecasting of swells in terms of time and location. The swells occurred in February 2008 are hindcasted using SWAN model to examine the accuracy of the model for future forecasting. The model results are compared with ReWW3 data as well as measurement wave data and specially, wave spectrum is analysed by comparing with observed spectrum at two wave stations located in the east coast of Korea. The SWAN model shows similar results with observation data in terms of significant wave heights and swell arrival time but the shapes of wave spectrum are different between model and in-situ measurement data. For further improvement of swell forecasting, more comparison and analysis with observed wave spectrum is necessary and wave directional spectrum data are required to study on the characteristics of swells in the East Sea.

• The Journal of Engineering Geology
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• v.15 no.1
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• pp.67-76
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• 2005

This paper presents the application of a neural network for prediction of the unconfined compressive strength from physical properties and schmidt hardness number on rock samples. To investigate the suitability of this approach, the results of analysis using a neural network are compared to predictions obtained by statistical relations. The data sets containing 55 rock sample records which are composed of sandstone and shale were assembled in Daegu area. They were used to learn the neural network model with the back-propagation teaming algorithm. The rock characteristics as the teaming input of the neural network are: schmidt hardness number, specific gravity, absorption, porosity, p-wave velocity and S-wave velocity, while the corresponding unconfined compressive strength value functions as the teaming output of the neural network. A data set containing 45 test results was used to train the networks with the back-propagation teaming algorithm. Another data set of 10 test results was used to validate the generalization and prediction capabilities of the neural network.