• Journal of Electrical Engineering and Technology
• /
• v.8 no.6
• /
• pp.1296-1304
• /
• 2013

This study performed an analysis on power demand reduction effects exhibited by demand response programs, which are advanced from traditional demand-side management programs, in the smart grid environment. The target demand response systems for the analysis included incentive-based load control systems (2 month-ahead demand control system, 1~5 days ahead demand control system, and demand bidding system), which are currently implemented in Korea, and price-based demand response systems (mainly critical peak pricing system or real-time pricing system, currently not implemented, but representative demand response systems). Firstly, the status of the above systems at home and abroad was briefly examined. Next, energy saving effects and peak demand reduction effects of implementing the critical peak or real-time pricing systems, which are price-based demand response systems, and the existing incentive-based load control systems were estimated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.299-304
• /
• 2008

Dynamic characteristics of smart hull structure are investigated and active vibration control performance is evaluated. Dynamic model of smart hull structure with surface bonded Macro-fiber Composite (MFC) actuators is established by analytical method. Equations of motion of the host hull structure are derived based on Donnell-Mushtari equilibrium equations for a thin cylindrical shell. A general model for the interaction between hull structure and MFC actuator is included in the dynamic model. Modal analysis is then conducted and mode shapes and corresponding natural frequencies are investigated. After constructing of the optimal control algorithm, active vibration control performance of the proposed system is evaluated. It has been shown that structural vibration can be reduced effectively with proper control input.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.8
• /
• pp.832-840
• /
• 2008

Dynamic characteristics of smart hull structure are investigated and active vibration control performance is evaluated. Dynamic model of smart hull structure with surface bonded macro-fiber composite(MFC) actuators is established by analytical method. Equations of motion of the host hull structure are derived based on Donnell-Mushtari equilibrium equations for a thin cylindrical shell. A general model for the interaction between hull structure and MFC actuator is included in the dynamic model. Modal analysis is then conducted and mode shapes and corresponding natural frequencies are investigated. After constructing of the optimal control algorithm, active vibration control performance of the proposed system is evaluated. It has been shown that structural vibration can be reduced effectively with proper control input.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.4
• /
• pp.998-1012
• /
• 2015

This study is smartphone addiction impulsiveness, stress, self-efficacy, and examine any changes to appear self-control. This study is a response to the results obtained for 310 people targeting high school in Pusan, the second grade students. For the analysis of the collected data by using the SPSS 22.0 program was the analysis of the T-test, ANOVA, Multiple Regression. The major findings of this study can be summed up as follows: first, smart phone addiction has significant difference in impulsivity, stress, self-efficacy, and self-control. Second, sex is found to be significant in impulsivity, stress, self-efficacy, and self-control. Third, grades are significant in impulsivity, self-efficacy, and self-control. Fourth, the model for impulsivity indicates 4% of explanatory power, which is significant. Fifth, explanatory power for stress is 4%, which is significant. Sixth, the model for self-efficacy shows 14% of explanatory power, which is significant. Meanwhile, smart phone addiction, sex, and grades have no significant effects on self-efficacy. Seventh, the model for self-control indicates 20% of explanatory power, which is significant.

• Journal of Power Electronics
• /
• v.15 no.5
• /
• pp.1338-1347
• /
• 2015

DC injection is a critical issue in transformerless grid-connected inverters. DC injection control based on virtual capacitor has the advantages of low cost, low loss, high accuracy and easy implementation. In this paper, the principle of DC injection control based on virtual capacitor was analyzed. In addition, the applicable conditions, working process, steady state error and advantages were also discussed in detail. The design of the control parameters based on virtual capacitor was proposed in a grid-connected inverter with LCL filter. The robustness of the control parameters was also discussed. Simulation and experimental results verify the validity of the analysis and demonstrate that this research has a certain value in engineering applications.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.9
• /
• pp.165-176
• /
• 2016

This study developed the learning ability-based smart education program. The effectiveness of the developed materials was investigated using the quantitative-qualitative mixed method, and the process and results of the investigation are as follows. The quantitative investigation was conducted using the non-equivalent pretest-posttest design, in which the smart education method was applied to the experimental group, while the conventional education method was applied to the control group to analyze students' creative problem-solving potential, task concentration, and the variables required for the learning activity. The results showed significantly higher performance in the experimental group over the control group. Regarding data collection in the qualitative investigation, an analysis of the class from the instructor and class consultation logs from the class analyst were collected; the comments on the experience of each class period were collected from students. The results of the analysis of the data suggest that the perception of smart education improved for the instructor, class analyst, and learners as the course progressed.

• Transactions of Materials Processing
• /
• v.24 no.3
• /
• pp.212-217
• /
• 2015

SmartCrown is a system to control the plate crown by shifting the sine-shaped work rolls in the axial direction. The control range of the plate crown depends on a depth of sine-shaped roll profile because the roll radius varies continuously along the axial direction. When the roll profile is changed to improve the control range, the contact stress between the work roll and the back-up roll also changes. In the current study, the contact stress for various profiles and rolling conditions were analyzed using the finite element method and compared with results from Hertzian contact theory. A submodel method is used to increase the accuracy of the finite element analysis. The analysis results showed that the maximum increase in the contact stress was only 53MPa, so it is anticipated that no back-up roll spalling will occur.

• Journal of Convergence for Information Technology
• /
• v.7 no.6
• /
• pp.103-111
• /
• 2017

The purpose of this study is to identify the factors affecting the adaptation, Self-esteem and self-control of college students to smart addiction. We surveyed 380 university students in Gwangju area. Data were analyzed by t-test, one-way ANOVA, Pearson correlation analysis. Smart phone addiction according to general characteristics showed the lowest in fourth grade and high in health-related majors. Smart phone usage time was the lowest in less than 3 hours due to the actual usage of smart phone. School life adaptation, self-esteem, and self-control according to general characteristics were higher in satisfaction with college life and majors. The most influential factors on the addiction of smart phone were perceived smart phone addiction, and the self-esteem and self-control were more likely to be addicted to smart phone. Therefore, it is necessary to develop education and programs to enhance self-esteem and self-control of college students and to find ways to prevent smart phone addiction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.466-471
• /
• 2008

Structural vibration and noise are hot issues in underwater vehicles such as submarines for their survivability. Therefore, active vibration and noise control of submarine, which can be modeled as hull structure, have been conducted by the use of piezoelectric materials. Traditional piezoelectric materials are too brittle and not suitable to curved geometry such as hull structures. Therefore, advanced anisotropic piezoceramic actuator named as Macro-Fiber Composite (MFC), which can provide great flexibility, large induced strain and directional actuating force is adopted for this research. In this study, dynamic model of the smart hull structure is established and active vibration control performance of the smart hull structure is evaluated using optimally placed MFC. Actuating performance of MFC is evaluated by finite element analysis and dynamic modeling of the smart hull structure is derived by finite element method considering underwater condition. In order to suppress the vibration of hull structure, Linear-Quadratic-Gaussian (LQG) algorithm is adopted. After then active vibration control performance of the proposed smart hull structure is evaluated with computer simulation and experimental investigation in underwater. Structural vibration of the hull structure is decreased effectively by applying proper control voltages to the MFC actuators.

• Journal of Information Technology Applications and Management
• /
• v.23 no.1
• /
• pp.61-77
• /
• 2016

This study derived research model about the influencing factors of the successful performance of smart work. Research model is composed of four perspectives: technology perspective like system quality and usage level of information technology, interaction perspective like innovational climate, institutional perspective like personnel evaluation, and individual perspective like self-control. This study collected 155 survey data from K public company and M global software company. As a result of data analysis, all of four perspectives influenced smart work performance. Technology perspective had the strongest effect on smart work performance, the second was institution perspective, the third was interaction perspective, and the last was individual perspective. In conclusion, smart work is not an IT project. We have to reconsider the thinking that just only the introduction of cutting-edge IT increases business performance. Smart work project should be pursued in harmony with institution and climate in the organizational perspective and self-control in the personal perspective. Also, to maximize business performance in smart work environment, organizations should strengthen the positive factors and overcome the negative factors.