• Structural Engineering and Mechanics
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• v.47 no.5
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• pp.679-700
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• 2013

Two new predictive design methods are presented in this study. The first is a hybrid method, called neuro-fuzzy, based on neural networks with fuzzy learning. A total of 280 experimental datasets obtained from the literature concerning concentric punching shear tests of reinforced concrete slab-column connections without shear reinforcement were used to test the model (194 for experimentation and 86 for validation) and were endorsed by statistical validation criteria. The punching shear strength predicted by the neuro-fuzzy model was compared with those predicted by current models of punching shear, widely used in the design practice, such as ACI 318-08, SIA262 and CBA93. The neuro-fuzzy model showed high predictive accuracy of resistance to punching according to all of the relevant codes. A second, more user-friendly design method is presented based on a predictive linear regression model that supports all the geometric and material parameters involved in predicting punching shear. Despite its simplicity, this formulation showed accuracy equivalent to that of the neuro-fuzzy model.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1607-1616
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• 2006

The growing market of multimedia and digital signal processing requires significant data-path portions of SoCs. However, the common models for verification are not suitable for SoCs. A novel model--WGL (Weighted Generalized List) is proposed, which is based on the general-list decomposition of polynomials, with three different weights and manipulation rules introduced to effect node sharing and the canonicity. Timing parameters and operations on them are also considered. Examples show the word-level WGL is the only model to linearly represent the common word-level functions and the bit-level WGL is especially suitable for arithmetic intensive circuits. The model is proved to be a uniform and efficient model for both bit-level and word-level functions. Then Based on the WGL model, a backward-construction logic-verification approach is presented, which reduces time and space complexity for multipliers to polynomial complexity(time complexity is less than $O(n^{3.6})$ and space complexity is less than $O(n^{1.5})$) without hierarchical partitioning. Finally, a construction methodology of word-level polynomials is also presented in order to implement complex high-level verification, which combines order computation and coefficient solving, and adopts an efficient backward approach. The construction complexity is much less than the existing ones, e.g. the construction time for multipliers grows at the power of less than 1.6 in the size of the input word without increasing the maximal space required. The WGL model and the verification methods based on WGL show their theoretical and applicable significance in SoC design.

• Korean Journal of Adult Nursing
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• v.18 no.3
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• pp.488-499
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• 2006

Purpose: Behavioral symptoms in dementia (BSD) are one of the most disturbing behaviors to caregivers and a major reason for nursing home placement. Behavioral symptoms are often treated with psychotropic drugs (PD), however, the effect of such drugs for the frail elderly dementia patient is not certain because of their critical adverse effects. Theoretical model applicable to nursing practice for BSD in nursing homes, which is essential in guiding and evaluating such interventions, is absent. This article presents the process of developing a theoretical model of BSD in nursing homes. Method: Using Walker and Avants' theory synthesis method, three behavior models and two system models were incorporated into the proposed model to provide the theoretical and analytical explanation of the relationships between PD usage, its determinants, and BSD. Results: Resident variables and nursing home variables related to the two focal concepts (i.e., PD usage and BSD) were identified. Resident variables include demographical characteristics such as age and gender, and dementia-compromised functions such as cognitive and functional impairment. Nursing home variables include facility characteristics such as ownership type and size, and physical and psychosocial environment. Conclusion: The proposed model suggests that fulfillment of resident unmet needs through improvement of physical and psychosocial environment may produce better health outcomes of nursing home residents with BSD. Assessment and intervening environmental triggers of such behaviors are also suggested to be prior to the PD usage.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.6
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• pp.415-423
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• 2021

There have been many experimental studies on the manoeuvrability of KRISO Container Ship (KCS). However, the scale ratio of the model ship and the test procedure for each institute are slightly different, so direct comparison for the data is technically difficult to perform. This paper presents the manoeuvrability of the ship with different scale ratios: 1/65.8, 1/42.0, and 1/31.6 in model scale. KRISO conducted Free Running Model Tests (FRMT): 35° turning circle tests and 20/20(10/10) zigzag manoeuvring tests. The test results indicated that advance and tactical diameter in turning circle tests were similar, and overshoot angles in two zigzag manoeuvring tests increased as the model ship size increased. In addition, a basic concept for the FRMT method with an auxiliary X-thrust device was proposed so that the scale effect could be considered in model ship tests.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.691-700
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• 2023

Purpose: This study aims to analyze the diffusion pattern of the Mongolian mobile phone market. In particular, we used a generalized diffusion model to explore the factors affecting market potenial. Methods: We used three diffusion models to estimate the number of mobile subscribers in Mongolia. Based on the Logistic model with the best fitness, we introduced time-varying market potential and explored the influence of various independent variables such as GDP and inflation. Results: Among the basic diffusion models, the Logistic model was the best in terms of estimation performance and statistical significance. The estimation results of the Generalized Logistic model confirm that investment in the telecommunication sector has a significant positive effect on market potential. The estimation of the Generalized Logistic model effectively describes the continuous growth of the Mongolian telecommunications market until recently. Conclusion: We have analyzed the diffusion pattern of the Mongolian telecommunications market and found that the amount of investment in the sector leads to the growth of the market size. This study is original in terms of its subject - Mongolian telecommunications market and methodology - time-varying market potential.

• Journal of Korea Water Resources Association
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• v.40 no.9
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• pp.677-685
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• 2007

The objective of this study is to evaluate the applicability of multi-objective genetic algorithm(MOGA) in order to calibrate the parameters of conceptual rainfall-runoff model, Tank model. NSGA-II, one of the most imitating MOGA implementations, is combined with Tank model and four multi-objective functions such as to minimize volume error, root mean square error (RMSE), high flow RMSE, and low flow RMSE are used. When NSGA-II is employed with more than three multi-objective functions, a number of Pareto-optimal solutions usually becomes too large. Therefore, selecting several preferred Pareto-optimal solutions is essential for stakeholder, and preference-ordering approach is used in this study for the sake of getting the best preferred Pareto-optimal solutions. Sensitivity analysis is performed to examine the effect of initial genetic parameters, which are generation number and Population size, to the performance of NSGA-II for searching the proper paramters for Tank model, and the result suggests that the generation number is 900 and the population size is 1000 for this study.

• 대한공업교육학회지
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• v.45 no.1
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• pp.20-41
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• 2020

The purpose of this study is to explore ways to improve teaching and learning in specialized high schools by investigating the relationship between creativity and class satisfaction in classes using the NFTM-TRIZ model for specialized high school students. In order to achieve the purpose of the research, first, the differences between the applied effects, experiments, and control groups were analyzed when the NFTM-TRIZ model was applied. Second, when the NFTM-TRIZ model was applied, it was analyzed whether there was a significant difference in creativity and class satisfaction by group size. The conclusions of this study are as follows. First, as a result of comparing the preand post-tests of the experimental group and the control group applying the NFTM-TRIZ model through the t-test, the experimental group showed significant differences in creative spontaneity, identity, attachment, curiosity and class satisfaction. Second, in experimental groups with the NFTM-TRIZ model, the size of groups of 4 and 6, rather than the size of groups of 2, had positive effects on class satisfaction. Therefore, the NFTM-TRIZ model based on collaborative learning was effective as a teaching and learning method that promoted creativity and satisfaction of students in specialized high schools.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.408-414
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• 2016

This study will find meaningful independent variables for criterion variables that affect influencing on purchase intention in social network service, on the basis of the results of a meta-analysis. We reviewed a total of 29 studies related purchase intention in social network service published in Korea journals between 2005 and 2015, where a cause and effect relationship is established between variables that are specified in the conceptual model of this study. The result of the meta-analysis might be summarized that the highest effect size (r = .455) is the path from the satisfaction to the purchase intention. The second biggest effect size (r = .398) was found in the path between the word of mouth to the purchase intention. Next, the effect size (r = .386) in the path from the trust to the purchase intention showed very lower. Finally, the result of the meta analysis can be concluded that lower effect size (r = .342) Further, the predictive variables of this study have power of explanation about 22%-12% or more. Based on these findings, several theoretical and practical implications were suggested and discussed.

• Steel and Composite Structures
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• v.36 no.2
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• pp.143-161
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• 2020

In nanosized structures as the surface area to the bulk volume ratio increases the classical continuum mechanics approaches fails to investigate the mechanical behavior of such structures. In perforated nanobeam structures, more decrease in the bulk volume is obtained due to perforation process thus nonclassical continuum approaches should be employed for reliable investigation of the mechanical behavior these structures. This article introduces an analytical methodology to investigate the size dependent, surface energy, and perforation impacts on the nonclassical bending behavior of regularly squared cutout nanobeam structures for the first time. To do this, geometrical model for both bulk and surface characteristics is developed for regularly squared perforated nanobeams. Based on the proposed geometrical model, the nonclassical Gurtin-Murdoch surface elasticity model is adopted and modified to incorporate the surface energy effects in perforated nanobeams. To investigate the effect of shear deformation associated with cutout process, both Euler-Bernoulli and Timoshenko beams theories are developed. Mathematical model for perforated nanobeam structure including surface energy effects are derived in comprehensive procedure and nonclassical boundary conditions are presented. Closed forms for the nonclassical bending and rotational displacements are derived for both theories considering all classical and nonclassical kinematics and kinetics boundary conditions. Additionally, both uniformly distributed and concentrated loads are considered. The developed methodology is verified and compared with the available results and an excellent agreement is noticed. Both classical and nonclassical bending profiles for both thin and thick perforated nanobeams are investigated. Numerical results are obtained to illustrate effects of beam filling ratio, the number of hole rows through the cross section, surface material characteristics, beam slenderness ratio as well as the boundary and loading conditions on the non-classical bending behavior of perforated nanobeams in the presence of surface effects. It is found that, the surface residual stress has more significant effect on the bending deflection compared with the corresponding effect of the surface elasticity, Es. The obtained results are supportive for the design, analysis and manufacturing of perforated nanobeams.

• Journal of Science Education
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• v.32 no.2
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• pp.51-70
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• 2008

The purposes of this study were to analyze the domestic research trend of the STS Education and to evaluate the application effects of STS teaching model by using Meta-analysis. The selected research articles were 180 articles including 104 of the master's theses and 76 of science education journal articles published from 1991 to 2006. For the evaluation of the effects of STS teaching and learning model, 56 articles were selected finally. The mean effect size of the application effects of STS teaching and learning was 0.40. The result indicated that STS teaching had more positive effects than the traditional teaching on enhancing student's attitude for science, academic achievement in science, inquiry ability, attitude for environment and knowledge for environment. Especially, it had shown the most positive effects on improvement in the attitude for environment. Therefore, it might be better to reflect these results for the best effect of STS teaching. To assess STS education on the whole, it is necessary to synthesize the effects of STS teaching and learning model and the results of the study on teachers' and students' understanding about the interrelation of science, technology and society.