• Earthquakes and Structures
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• v.26 no.2
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• pp.117-130
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• 2024

Probabilistic model of seismic demand is the main tool used for seismic demand estimation, which is a fundamental component of the new performance-based design method. This model seeks to mathematically relate the seismic demand parameter and the ground motion intensity measure. This study is intended to use Bayesian analysis to evaluate the accuracy of the seismic demand estimation of Steel moment resisting frames (SMRFs) through a completely Bayesian method in statistical calculations. In this study, two types of intensity measures (earthquake intensity-related indices such as magnitude and distance and intensity indices related to ground motion and spectral response including peak ground acceleration (PGA) and spectral acceleration (SA)) have been used to form the models. In addition, an extensive database consisting of sixty accelerograms was used for time-series analysis, and the target structures included five SMRFs of three, six, nine, twelve and fifteen stories. The results of this study showed that for low-rise frames, first mode spectral acceleration index is sufficient to accurately estimate demand. However, for high-rise frames, two parameters should be used to increase the accuracy. In addition, adding the product of the square of earthquake magnitude multiplied by distance to the model can significantly increase the accuracy of seismic demand estimation.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.1-6
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• 2024

This study aims to suggest the partition ratio (Q-factor) of healthy Koreans and the comparison results of breath alcohol concentration (BAC) measurements using two methods (photoacoustic and electrochemical methods) for developing breath alcohol ignition interlock devices (BAIIDs). Given the relationship between BACs and BrACs and the Q-factor, the alcohol metabolism of healthy Koreans (96 males and 91 females) is revealed for understanding the digestion of alcohol and surveying the fundamental data of alcohol-related problems, CO₂ concentrations vs. alcohol concentrations, and the performance of alcohol sensors in the marketplace. The average Q-factor of healthy Korean males and females are 1,913 (95% confidence interval from 1,889-1,937) and 1,991 (95% confidence interval from 1,945-2,036). Photoacoustic measurements could be applied to predict the BACs of drinkers, which is confirmed by the Bland-Altman plots presented in this study. The biases based on the partition ratios (Q=1,913 and Q=1,991) in the Bland-Altman plots were -0.0004% (95% CI from -0.0011 to +0.0003% for males) and -0.0017% (95% CI from -0.020 to +0.017% for females).

• Korean Journal of Applied Biomechanics
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• v.34 no.2
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• pp.63-70
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• 2024

Objective: This study aims to compare the basic aerodynamic characteristics of the official Qatar World Cup soccer ball with those of the official Korean soccer balls. Method: In this study, wind tunnel experiments were conducted to compare the fundamental aerodynamic properties of two commonly used domestic soccer balls, the Star and Nassau, with the Al Rihla, the official ball of the 2022 Qatar World Cup. Results: The findings revealed that the Nassau soccer ball exhibited changes in aerodynamic characteristics depending on its orientation, particularly at low speeds (below 15 m/s), while the Al Rihla showed variations in aerodynamic characteristics at medium to high speeds (15 m/s to 35 m/s) based on its orientation. Furthermore, the results of lift and side force variations indicated that the Star soccer ball exhibited larger changes compared to other soccer balls, suggesting that it may exhibit the most irregular flight path during strong shots (around 30 m/s or approximately 100 km/h). However, there were no differences in aerodynamics observed among the soccer balls in the medium-speed range (20~25 m/s). Conclusion: The comparison of aerodynamics between the Korean soccer balls and the most recently used World Cup official ball showed that, while the Korean balls exhibited slightly greater changes in lift and side forces compared to the World Cup ball, there were no significant differences in most of the aerodynamic characteristics.

• Tribology and Lubricants
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• v.40 no.1
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• pp.24-27
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• 2024

A monotype valve body for a dual clutch transmission has the potential to reduce costs, weight, and manufacturing time by modularizing various parts, including those of existing solenoid packs and valve bodies, into one through the application of super-precision die casting technology. However, this approach may lead to challenges such as reduced rigidity and increased interference due to modularization and compactness, impacting both product performance due to the reduced weight as well as durability and reliability. Unlike existing products, this approach requires a high-precision thin-wall block to avoid more complicated flow line formation, interference between flow lines, and leaks, as well as a strict quality requirement standard and precise inspections including detection of internal defects. To conduct precise inspections, we built an equivalent model corresponding to a driving distance of 300,000 km. Testing involved simulating actual road loads using a real vehicle and a chassis dynamometer in the FTP-75 mode (EPA Federal Test Procedure). The aim of the study was to establish a vehicle load-based part durability model for manufacturing a mono-type valve body and to develop fundamental technology for part weight reduction through preliminary design by introducing analytical weight reduction technology based on the derived results.

• East Asian Journal of Business Economics (EAJBE)
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• v.12 no.2
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• pp.43-50
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• 2024

Purpose: The present study investigates if the type of organizational culture influences the level of job-related stress. This study is significant because creating the need to explore the concept to become more informed on the best practices to promote and foster a positive culture that prioritizes workers, it could result in a healthier workforce, improved organizational performance, and success. Research design, data and methodology: Examining previous studies by other researchers was the primary research tool for this study. The organized approach of gathering data and assessing related work was vital in developing a fundamental basis for advancing knowledge on this concept while enhancing theory development and drawing more informed conclusion. Results: These four types, including the clan, adhocracy, hierarchical, and market cultures, contribute significantly in revealing four associations between the two variables, including (i) supportive culture and reduced stress, (ii) high pressure and increased stress, (iii)autonomous culture and variable stress levels, and (iv) open culture and low-stress levels. Conclusions: The literature affirms a multifaceted link between employee workplace stress and organizational culture type. The findings show that these cultures are crucial in influencing the level of stress among employees. All four types were hypothesized to have a significant relationship with job stress.

• The Journal of Industrial Distribution & Business
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• v.15 no.5
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• pp.39-46
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• 2024

Purpose: This study seeks to address the following research questions: (1) What are the fundamental principles of sports psychology that can be applied to business leadership? (2) How can these principles enhance business leadership effectiveness? As a result, the study may evaluate the necessity and benefits of incorporating sports psychology principles into business leadership practices. Research design, data and methodology: The data collection process in this study involved a systematic Literature review approach, following the prior literature analysis guidelines by numerous past studies. This methodical approach to selecting articles can be useful in synthesizing existing literature and can be referred to as Literature review and selection. Results: The literature analysis has indicated that there is much support for assumptions underpinning business leadership modules, which can be enhanced by applying sports psychology. This topic discusses the traits of self-positivity and mental toughness, goal perspective and interpersonal relationships within a team, and visualization in a sporting organization that can be implemented in business management to support organizational performance. Conclusions: All in all, it can be concluded that organizations must consider adopting Sports Psychology principles into their Leadership Development Programs. Psychological skills development training that includes mental toughness, goal setting, team cohesion,

• Journal of Sensor Science and Technology
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• v.33 no.4
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• pp.216-223
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• 2024

Electric propulsion systems, including electrothermal, electrostatic, and electromagnetic thrusters, are promising systems for producing thrust from satellites. These systems generally operate under vacuum plasma conditions and exhibit high specific impulses and thrust-to-weight ratios. Despite their high efficiencies, electric propulsion systems are susceptible to performance variations due to physical factors such as plasma instabilities, which require an accurate diagnosis of their status during operation. In this study, we review various measurement systems adopted to diagnose electric propulsion systems operating under vacuum conditions. Specifically, we review electrical, optical, and other methods that can directly or indirectly measure the status of a thruster, with a particular focus on Hall effect thrusters. The system configurations and fundamental mechanisms of the different measurement systems are described based on case studies of the diagnosis of propulsion systems. We anticipate that this study will contribute to the efficient development and safe operation of electric propulsion systems for use in artificial satellites.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.183-194
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• 2005

In this study, we introduce an advanced architecture of genetically optimized Hybrid Fuzzy Neural Networks (gHFNN) and develop a comprehensive design methodology supporting their construction. A series of numeric experiments is included to illustrate the performance of the networks. The construction of gHFNN exploits fundamental technologies of Computational Intelligence (CI), namely fuzzy sets, neural networks, and genetic algorithms (GAs). The architecture of the gHFNNs results from a synergistic usage of the genetic optimization-driven hybrid system generated by combining Fuzzy Neural Networks (FNN) with Polynomial Neural Networks (PNN). In this tandem, a FNN supports the formation of the premise part of the rule-based structure of the gHFNN. The consequence part of the gHFNN is designed using PNNs. We distinguish between two types of the linear fuzzy inference rule-based FNN structures showing how this taxonomy depends upon the type of a fuzzy partition of input variables. As to the consequence part of the gHFNN, the development of the PNN dwells on two general optimization mechanisms: the structural optimization is realized via GAs whereas in case of the parametric optimization we proceed with a standard least square method-based learning. To evaluate the performance of the gHFNN, the models are experimented with a representative numerical example. A comparative analysis demonstrates that the proposed gHFNN come with higher accuracy as well as superb predictive capabilities when comparing with other neurofuzzy models.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.255-264
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• 2009

Permeability coefficient of concrete is a substaintial key parameter for understanding the durability performance of concrete and its microstructural densification. Many researches for the issue have been accomplished, however, it is very rare to deal with the theoretical study on permeability coefficient in connection with carbonation of concrete and the the effect of volumetric fraction of cement paste or aggregate on the permeability coefficient. The majority of these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impact on the permeability coefficient of concrete. The purpose of this study is to establish a fundamental approach to compute the permeability coefficeint of (non)carbonated concrete. When simulating a microstructural characteristics as a starting point for deriving a model for the permeability coefficient by the numerical simulation program for cementitious materials, HYMOSTRUC, a more realistic formulation can be achieved. For several compositions of cement pastes, the permeability coefficient was calculated with the analytical formulation, followed by a microstructure-based model. Emphasis was on the microstructural changes and its effective change of the permeability coefficient of carbonated concrete. For carbonated concrete, reduced porosity was calculated and this was used for calculating the permeability coefficeint. The computational result was compared with experimental outcome.

• The Journal of Korean Academic Society of Nursing Education
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• v.7 no.1
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• pp.94-112
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• 2001

The main purpose of this study was to investigate the effectiveness of a standardized patients managed instruction program for a fundamentals of nursing. The standardized patients managed instruction was evaluated by using a quasi-experimental, nonequivalent control group posttest design with two separate classes of sophomore students attending fundamentals of nursing classes at one baccaleureate nursing school in Korea. Control group was taught by traditional lecture/model instruction and experimental group was taught by standardized patient managed instruction. Data were collected from December, 1999 to July, 2000 using checklist developed by researcher on following areas; clinical nursing performance, communication skills, and learning motivation. There were 36 students in the experimental group and 40 students in the control group. Data analysis was done using SPSS WINDOW. The results were summarized as follows ; 1. Clinical nursing performances were evaluated by change position, back care and hot bag apply. The total score was statistically significant higher in the experimental group than the control group(t=3.325, p=.000). Thus hypothesis 1 was supported. 2. Communication skill was evaluated by professional attitude and ability to explain to patients. There was a statistically significant difference between the experimental group and the control group (t=4.232, p=.000). Thus hypothesis 2 was supported. 3. Learning motivation was evaluated by self-reported questionnaires. There was statistically a significant difference between the experimental group and the control group(t=3.024, p=.004). Thus hypothesis 3 was supported. In conclusion, this study suggests that standardized patients managed instruction is an effective learning method to nursing students. By utilizing a standardized patient managed instruction, learning can proceed in a more relaxed environment and reduce the risks to patients because student inexperience are avoided. It is recommended to develop more standardized patients cases for wider areas of nursing educational and evaluate the program with more students using logitudinal method.