• Journal of the Korean GEO-environmental Society
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• v.24 no.2
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• pp.13-24
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• 2023

Tunnels may undergo a larger or a smaller response compared with the free-field soil. In the pseudo-static procedure, the response of the tunnel is most often characterized by a curve that relates the racking ratio (R) with the flexibility ratio (F), where R represents the ratio of the tunnel response with respect to the free-field vibration and F is the relative stiffness of the tunnel and the surrounding soil. A set of analytical and empirical curves that do not account for the depth and the aspect ratio of the tunnel are typically used in practice. In this study, a series of dynamic analyses are conducted to develop a set of F-R_m relations for use in a frame analysis method. R_m is defined as an adjusted R where the rocking mode of deformation is removed and only the racking deformation is extracted. The numerical model is validated against centrifuge test recordings. The influence of aspect ratio, buried depth of tunnel on results is investigated. The results show that R_m increases with the increase of the buried depth and the aspect ratio. The widely used F-R relations are highlighted to be different compared with the obtained results in this study. Therefore, the updated F-R_m relations with proposed equations are recommended to be used in practice design. The rocking response decreases with either the decrease of the difference of stiffness between surrounding soil and tunnel or the larger aspect ratio of the tunnel section.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.369-375
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• 2004

Gas turbine engine simulation in terms of transient, steady state performance and operational characteristics is complex work at the various engineering functions of aero engine manufacturers. Especially, efficiency of control system design and development in terms of cost, development period and technical relevance implies controlling diverse simulation and identification activities. The previous engine simulation has been accomplished within a limited analysis area such as fan, compressor, combustor, turbine, controller, etc. and this has resulted in improper engine performance and control characteristics because of limited interaction between analysis areas. In this paper, we propose a new simulation methodology for gas turbine engine performance analysis as well as its digital controller to solve difficulties as mentioned above. The novel method has particularities of (ⅰ) resulting in the integrated control simulation using almost every component/module analysis, (ⅱ) providing automated math model generation process of engine itself, various engine subsystems and control compensators/regulators, (ⅲ) presenting total sophisticated output results and easy understandable graphic display for a final user. We call this simulation system GT3GS (Gas Turbine 3D Graphic Simulator). GT3GS was built on both software and hardware technology for total simulation capable of high calculation flexibility as well as interface with real engine controller. All components in the simulator were implemented using COTS (Commercial Off the Shelf) modules. In addition, described here includes GT3GS main features and future works for better gas turbine engine simulation.

• Journal of Sport and Applied Science
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• v.7 no.3
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• pp.19-26
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• 2023

Purpose: This study attempted to investigate the effect of functional rehabilitation exercise for posture correction on physical strength factors and physical balance. Research design, data, and methodology: It consisted of 40 experimental groups that applied functional rehabilitation exercises to 80 people with posture imbalance and 40 comparative groups that performed general exercises, and was conducted four times a week, once for 40 minutes, and for 12 weeks. Results: D.S. (p<.o1) among F.M.S., a moving assessment. It increased significantly from the dictionary, and H.S. (p<.o5). I.L(p<.o5). S.M(p<.o5). A.S.L.R(p<.o5). T.S.P(p<.o01). It was confirmed that R.S. (p<.o5) decreased more after than before. In other words, Functional rehabilitation exercise was effective in improving physical balance. PAPS flexibility (bending forward) (p<.o1). Muscle strength (grip strength test) (p<.o1). Quickness (long jump) (p<.o1). Functional rehabilitation exercise was found to be effective in muscle strength, agility, and flexibility, but not in cardiopulmonary endurance. Pain: Based on the NRS scale (1-10 points). The experimental that there was a significant interaction between the groups.(F=38.583, P=.000). In the comparative group, there was no significant difference in the pre-post, and it was found that the pain level in the experimental group decreased after the pre-post (p<.001). Conclusion: As a result of the above study, it was confirmed that functional rehabilitation exercise improves physical strength factors and physical balance ability, and also affects physical pain reduction due to physical imbalance.

• Journal of Korean Home Economics Education Association
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• v.35 no.1
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• pp.139-155
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• 2023

The purpose of this study is to improve the digital literacy of pre-service home economics education teachers by designing and applying 'teaching materials and methods of home economics education' class using the Metaverse platform in virtual classes during the Covid-19 pandemic. For this purpose, six lessons of the 'Teaching Materials and Methods of Home Economics Education' classes were designed and applied as a class using the Metaverse platform, and the effectiveness was analyzed. In this study, three types of classes(TBL, discussion, and PBL) were developed and evaluated. The results of the study showed that most of the learners were satisfied with the classes utilizing the Metaverse platform, and the effectiveness of the classes was shown in terms of learner-instructor interaction and the realism of actual classroom cases. Based on these results, it is expected that various home economics education classes utilizing metaverse platforms will be developed and applied to school sites to increase the realism of lessons.

• Wind and Structures
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• v.35 no.4
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• pp.255-268
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• 2022

Light-weight or low-damped structures may encounter the unsteady galloping instability that occurs at low reduced wind speeds, where the classical quasi-steady assumption is invalid. Although this unsteady phenomenon has been widely studied for rectangular cross sections with one side perpendicular to the incidence flow, the effect of the mean wind angle of attack has not been paid enough attention yet. With four sectional models of different side ratios and geometric shapes, the presented research focuses on the effect of the wind angle of attack on unsteady galloping instability. In static tests, comparatively strong vortex shedding force was noticed in the middle of the range of flow incidence where the lift coefficient shows a negative slope. In aeroelastic tests with a low Scruton number, the typical unsteady galloping, which is due to an interaction with vortex-induced vibration and results in unrestricted oscillation initiating at the Kármán vortex resonance wind speed, was observed for the wind angles of attack that characterize relatively strong vortex shedding force. In contrast, for the wind angles of attack with relatively weak shedding force, an "atypical" unsteady galloping was found to occur at a reduced wind speed clearly higher than the Kármán-vortex resonance one. These observations are valid for all four wind tunnel models. One of the wind tunnel models (with a bridge deck cross section) was also tested in a turbulent flow with an intensity about 9%, showing only the atypical unsteady galloping. However, the wind angle of attack with the comparatively strong vortex shedding force remains the most unfavorable one with respect to the instability threshold in low Scruton number conditions.

• The Journal of Korean Academic Society of Nursing Education
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• v.29 no.1
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• pp.27-40
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• 2023

Purpose: The study aimed to examine the concept and attributes of the quality of clinical nursing education for new graduate nurses. Methods: This study adopted a hybrid model introduced by Schwartz-Barcott and Kim. In the theoretical stage, the meaning and attributes of the quality of clinical nursing education for new graduate nurses were determined by analyzing eight articles. In the fieldwork stage, data were collected using semi-structured interviews with five new graduate nurses and seven experienced nurses. The data were analyzed by qualitative content analysis methods developed by Elo and Kyngӓs. In the final analysis, a final result was arrived at comparing, contrasting, and integrating the attributes of the concepts derived in the theoretical and field-work stages. Results: The quality of clinical nursing education for new graduate nurses was identified as excellence or the standard of education for new graduate nurses that would support them in adapting to clinical settings and transitioning to professional nurses. The attributes of the quality of clinical nursing education were founded to possess three dimensions, six categories, and 18 attributes. The multidimensional attributes of the quality of clinical nursing education for new graduate nurses were confirmed as education resources, design, method, content, evaluation, interaction, and outcome under the three dimensions of input, process, and output. Conclusion: The concept and nature of the quality of clinical nursing education observed in this study can be utilized as a basis for the future development, evaluation, and improvement of clinical nursing education for new graduate nurses in healthcare organizations.

• Journal of the Korean Geotechnical Society
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• v.22 no.8
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• pp.25-31
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• 2006

Over the years the investigation of behaviour of piles in groups connected to a cap in consolidating soil has attracted far less attention than the study of isolated piles in groups. In this paper, a series of three-dimensional numerical simulations have been performed to study the behaviour of pile groups connected to a cap in consolidating ground. Both elastic no-slip and elasto-plastic slip analyses were considered. Based on the analysis results, when piles were connected to a cap, tensile forces were developed near the pile head at the outer piles. Elastic solution and no-slip analysis over-predicted the tensile force near the pile head for outer piles. Relatively speaking, the number of piles in a group is more important than the pile spacing in terms of the influence of negative skin friction on the pile behaviour. The issue on the development of tensile forces on the pile head at the outer piles is perhaps needed to be carefully considered in the pile design to prevent the damages of the pile-cap connection.

• Journal of Korea Trade
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• v.26 no.6
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• pp.83-95
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• 2022

Purpose - With the recent spread of COVID-19, U.S. consumers' consumption pattern is changing towards purchasing large-capacity products, as they stay at home longer. Thus, the current research investigates the effects of box shape and component diversity for large-sized products on product evaluation in logistic business. Moreover, this research examines that information-processing fluency mediates the moderating effects of box shape and product components on target evaluations to confirm psychological mechanism for generating this effect. Design/methodology - In order to examine the hypotheses, the current research conducts two online experiments. The 184 participants (Study 1), and 205 participants (Study 2) of U.S. nationality were recruited through Amazon Mechanical Turk. This research analyzes the data by using SPSS 25 and PROCESS macro 4.0. Findings - Study 1 demonstrates that when the height of a box is greater than its width, products with single components promote positive target evaluations, while when the width of box is greater than its height, products with a variety of components lead to positive target evaluations. Study 2 shows that the same results are replicated in other product categories and with different box shape ratios. Moreover, Study 2 also finds that the ease of information processing mediates the interaction effects of box shape and component diversity on U.S. consumers' target evaluations. Originality/value - The current research has originality in that it investigates the effect of box shape and product composition diversity on U.S. consumer product evaluation from the perspective of information-processing theory Moreover, this research has practical implications for global traders who prepare for entering the U.S. market.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.201-209
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• 2009

According to previous researches about online evaluation in many e-Learning contents, it took too much time and effort to generate test questions for formative or achievement tests using a database as an item pool. Furthermore, it is hard to measure accomplishment of learners for each unit through overall tests provided by existing e-learning contents. In this paper, to efficiently cope with problems described above, the item pool based on Item Form was transformed into Interaction Date Model in Run-Time Environment of SCORM2004. And the contents for the math concepts and principles that students would learn from regular classroom were developed in accordance with SCORM. In addition, Confidence Factor Function was used to take an objective view in measuring the accomplishment of learners through the items automatically generated by LMS(Learning Management System).

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.655-668
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• 2021

The present study was conducted to investigate the effects of the supplementation of Achyranthes japonica extract (AJE) on overall performance levels with different nutrition concentrations in the diets of finishing pigs. Here, 140 finishing pigs with initial body weights of 50.18 ± 2.37 kg were used in a ten-week trial involving a 2 × 2 factorial design in two phases with the following factors: diet types with different nutrition concentrations (Positive control [PC] vs. Negative control [NC]) and 0 or 0.05% AJE supplementation to NC and PC diets. The PC diet was a basal diet, whereas the NC diet consisted of a 5% and 7% crude protein (CP) reduced basal diet during phase 1 (1 - 35 days) and phase 2 (36 - 70 days), respectively. A significant effect (p < 0.05) on the gain-to-feed ratio (G : F) was observed with interaction effects between the diets and AJE supplementation. However, during phase 1 and in all periods, the pigs fed the PC and NC diets with average daily feed intake (ADFI) tended to decrease compared to those fed diets with AJE. A significant effect (p = 0.0380) of E. coli was observed in pigs fed the PC and NC diets compared to AJE supplementation in phase 2 of the experiment. The backfat thickness (BFT) tended to decrease and the lean meat percentage (LMP) was significantly improved in phase 2 for pigs fed the PC and NC diets. In summary, BFT and LMP showed beneficial effects and fecal microbiota of E. coli counts were positively affected when pigs were fed diets with different nutrient concentrations.