• Advances in Computational Design
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• v.3 no.2
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• pp.133-146
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• 2018

The paper discusses numerical analysis of tensile notched specimens with the use of Gurson - Tvergaard - Needleman (GTN) material model. The analysis concerned S235JR and S355J2G3 steel grades, subjected to medium stress state triaxiality ratio, amounting 0.739. A complete procedure for FEM model preparation was described, paying special attention to the issue of determining material constants in the GTN model. An example of critical void volume fraction ($f_c$) experimental determination procedure was presented. Finally, the results of numerical analyses were discussed, indicating the differences between steel grades under investigation.

• 한국데이터정보과학회:학술대회논문집
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• 2005.04a
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• pp.145-154
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• 2005

There have been some controversies on the use of the coefficient of determination for linear no-intercept model. One definition of the coefficient of determination, $R^2=\sum\;{y}{^{\hat{2}}/\sum\;{y^2}$, is being widely accepted only for linear no-intercept models though Kvalseth(1985) demonstrated some possible pitfalls in using such $R^2$. Main objective of this article is to provide a cautionary notice for use of the $R^2$ by pointing out its tricky aspects by means of empirical simulations.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.327-333
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• 2017

This study presents the orbit determination (OD) of a candidate Korea Regional Navigation Satellite System (KRNSS) using both inter-satellite links (ISLs) and ground observations. The candidate constellation of KRNSS is first introduced. The OD algorithm based on both ISL and ground observation is developed, and consists of three main components: dynamic model for Korean navigation satellites, measurement model for ISLs and ground observations, and the batch least-square filter for estimating OD parameters. As numerical simulations are performed to analyze the OD performances, the present study focuses on investigating the effects of ISL measurements on the OD accuracy of KRNSS. Simulation results show that the use of ISLs can considerably enhance the OD accuracy to one meter (design preference) under certain distributions of ground stations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1452-1460
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• 2001

A new method of parameter determination in the fatigue residual strength degradation model is proposed. The new method and minimization technique is compared experimentally to account for the effect of tension-compression fatigue loading of spheroidal graphite cast iron and graphite/epoxy laminate. It is shown that the correlation between the experimental results and the theoretical prediction on the fatigue life and residual strength distribution using the proposed method is very reasonable. Therefore, the proposed method is more adjustable in the determination of the parameter than minimization technique for the prediction of the fatigue characteristics.

• Journal of Information Technology Applications and Management
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• v.12 no.3
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• pp.57-80
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• 2005

This study defined the notion of general idea on m-learning as based upon e-Learning and mobile internet related literature review and identified the m-Learning distinctive features. Also, this study has searched for factors that are expected to influence the use intended for m-Learning from self-regulated learning, which is acknowledged to be a useful method for learning accomplishment in education field, in order to measure the relationship between learners' motivation and use intention. Then it has empirically validated the conceptual model based on Davis' TAM (Technology Acceptance Model) As a result, self-efficacy, self-determination, interest, contents quality, time management, help seeking, and Peer study are factors affecting Perceived usefulness. Also self-efficacy, self-determination, interest, contents qualify, time management, and peer study are factors affecting perceived ease of use. Finally both perceived usefulness and perceived ease of use are significant factors affecting use intention.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.7 no.2
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• pp.7-19
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• 1989

The developments in remote-sensing, digital mapping, and automation of land information system have provided the impetus for the increasing use of Digital Terrain Models in engineering planing and design. In this paper, an evaluation is made on tile method of accurate earth-volume determination in computerized road design using by Digital Terrain Models. The result of numerical test shows that the $BL_{in}$-1 Model is the most efficient model in Earth-volume determination of road design.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.32.1-32.1
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• 2020

An independent determination of H0 is crucial given the growing tension of the Hubble constant (H0). In this work, we present a new determination of H0 using velocities and Tip of the Red Giant Branch (TRGB) distances to 33 galaxies in front of the Virgo Cluster. We model the infall pattern of the local Hubble flow modified by the Virgo mass, as a function of the H0, the radius of the zero-velocity surface R0, and the intrinsic velocity scatter. Fitting velocities and TRGB distances of 33 galaxies to the model, we obtain H0 = 65.6 +/- 3.4 (stat) +/- 1.0 (sys) km/s/Mpc and R0 = 6.96 +/- 0.35 Mpc. Our local H0 is consistent with the global H0 determined from cosmic microwave background radiation, showing no tension.

• Journal of Korea Water Resources Association
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• v.42 no.7
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• pp.559-569
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• 2009

Due to environmental, economical and the other limitations, it has been more difficult to construct new large hydraulic structure such as dam. For this reason, it has been tried to use small hydraulic structure such as washland as alternative of hydraulic facility. Because the flood control effect of small hydraulic structure are affected by runoff volume, hydrograph, storage capacity and weir crest elevation, and design frequency must be predetermined for the design of the hydraulic structure. Multiple washlands will be required to satisfy enough peak reduction effect so that considering washlands as a network, rather than individually, are critical to analysis of flood reduction effect. In this study, new index for determination of optimal location for washlands is presented and the existing model for this determination is modified by adopting the new index. Developed new model is applied to Ansung river basin for examination and the new model shows its' applicability as a decision making criteria for the determination of optimal location for washlands.

• Journal of Biosystems Engineering
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• v.29 no.1
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• pp.65-70
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• 2004

This study was carried out to verify and predict the soil informations such as the contents of organic matter(OM) and Mg and pH of the soil. The predictability of spacial variation in the paddy field was examined by analyzing the various soil information. The prediction models for the OM pH, and Mg, were developed using inverse distance weighted (IDW), triangulated irregular network(TIN) and Kriging model. The determination of coefficients of linear and spherical Kriging models were 0.756 and 0.578, respectively, and were very low in comparison with other soil information. For IDW and TIN model, the determination of coefficients were 1.000 and hence the performance of the models was found to be excellent. The developed models were validated using unknown soil sample obtained In 2000 and 2001. From the analysis of relationship between the measured pH and predicted 0.9353. For prediction of Mg, the determination of coefficient is more than 0.8. Since the determination of coefficients of developed models for OM were relatively low, it may be difficult to predict the content of OM using the developed models. For further study, the additional works to enhance the performance of the prediction models for soil information are required.

• The Journal of Information Systems
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• v.31 no.3
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• pp.131-152
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• 2022

Purpose The purpose of this study was to investigate the intention of using a news media platform using block chain through media company workers in a situation where various platform services using block chain are being newly released in the media industry. Therefore, in this paper, we intend to explore the development direction of the news media platform service using the block chain in the future by deriving implications through the characteristics of the block chain, user characteristics, and self-determination factors. Design/methodology/approach This study conducted a survey on the main characteristics of blockchain, user characteristics, self-determination, resistance to innovation, etc., and designed a research model by integrating factors on the continuity of intention to use the news media platform. Findings According to the empirical analysis result, in this study, it was confirmed that the intention to use the blockchain news media platform is significantly related to decentralization, which is a characteristic variable of the blockchain, perceived risk, which is a user characteristic variable, and competence and relationship, which is a self-determination variable. In addition, it was confirmed that it affects the perceived ease of use with respect to the intention to use. In addition, in this study, news writers write more careful articles as they cannot edit articles once written, which can contribute to improving the quality of news content.