• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.692-695
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• 1997

Nonlinear robust attitude controller for 3-axis stabilized spacecraft is designed. Robust stability analysis for nonlinear spacecraft system with disturbance is conducted. External disturbances and parametric uncertainties decrease Spacecraft's attitude pointing accuracy. Sliding Mode Control(SMC) provides stability of system in the face of these disturbances and uncertainties. The concept of quadratic boundedness and quadratic stability are applied to the robust analysis for the nonlinear spacecraft system subject to bounded disturbance torques. Numerical simulation is conducted to compare the analysis result and actual nonlinear simulation. The simulation show that analysis result is valid.

• Journal of Astronomy and Space Sciences
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• v.10 no.1
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• pp.1-16
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• 1993

Three typer of spin-axis attitude determination program for the geosynchronous transfer orbit spacecraft are developed. Deterministic closed-from algorithm, batch least-square algorithm and stabilized Kalman filter algorithm are used for implemetation of three programs. EUROSTAR bus model from British Aerospace is used for attitude sensor modelling. Attitude determinations using three programs are performed for the simulated sensor data according to INMARSAT 2-F1 prelaunch mission analysis.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1881-1886
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• 2005

This paper proposes a novel approach of a precision attitude determination algorithm using UVF (Unit Vector Filter) measurements. The proposed method is superior to the conventional QUEST measurements based approaches because the estimation performance can be greatly enhanced by selecting brighter stars having better noise characteristics. The performance comparison with QUEST measurements is made to verify the usefulness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.173.3-173
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• 2001

In this paper, attitude control of autonomous system using bike based on variable structure control is discussed. Variable structure control is more than a promising technique in the field of nonlinear control. It permits the realization of very robust and simple regulators, with appealing sliding mode characteristics especially if the considered dynamics requires a very short sampling time. We derive dynamic equation of it and demonstrate that the designed controller stabilizes attitude simultaneously regardless of wheel position by computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.3-3
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• 2000

Limit cycle analysis of attitude control system using gas jet thrusters is performed. Schmitt-Trigger and PD control laws are applied and solenoid valve time delay is considered. Phase plane method is used for calculation of characteristics of limit cycle. Important characteristics of resultant limit cycle such as frequency, amplitude, maximum rate, and duty ratio could be expressed analytically by proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.189-189
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• 2000

A controller test on a sounding rocket using a testbed is discussed in the paper. Because of the high cost and the risk for the flight test the hardware simulation on the ground is performed. In this paper the conventional On/Off Controller is applied to the attitude control of a sounding rocket. The hardware simulation results are compared with those of the software simulation.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.41-43
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• 2004

This paper is concerned with attitude estimation using low cost, small-sized accelerometers and gyroscopes. A two step extended Kalman filter is proposed, which adaptively compensates external acceleration. External acceleration is the main source of estimation error. In the proposed filter, direction of external acceleration is estimated. According to the estimated direction, the accelerometer measurement covariance matrix of the two step extended Kalman filter is adjusted. The proposed algorithm is verified through experiments.

• The Research Journal of the Costume Culture
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• v.17 no.4
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• pp.709-722
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• 2009

At the end of April, 2009, the number of mobile phone users reached about 46 million in Korea. Consequently, the mobile shopping market is growing rapidly, and fashion products are one of the most concerned categories in mobile shopping market. In the meantime, the growth rates of domestic fashion industry and fashion retail market are forecasted very slow. In this situation, however, the growth rate of on-line shopping market including internet shopping, TV home shopping, and mobile shopping is estimated more than 12% per year until 2010. Particularly, mobile shopping area is forecasted the most rapid growing field. The objective of this study were to confirm the factors which had influences on mobile fashion shopping and to examine the effects of these factors affect the attitude toward mobile fashion shopping and the using intention of mobile fashion shopping. With the results, marketing strategies for mobile fashion shopping companies would be proposed. Date were gathered from 125 respondents of 20's and 30's females and were analyzed by AMOS 7.0. The key points of the results are; 1) The 5 factors of instant access, individualization, amusement, usefulness and ease of use which extracted from preceding researches were confirmed as the characteristics of mobile fashion shopping, 2) among these factors, amusement and usefulness had positive influences on the attitude toward mobile fashion shopping, 3) reliability on mobile fashion shopping didn't had an influence on the attitude toward mobile fashion shopping significantly, but had a positive influence on the using intention of mobile fashion shopping directly, and 4) the attitude toward mobile fashion shopping affects using intention of mobile fashion shopping positively. With these results, mobile fashion shopping companies can establish marketing strategies from various angles.

• Korean Journal of Childcare and Education
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• v.19 no.2
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• pp.61-85
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• 2023

Objective: This study aims to investigate whether science teaching attitude of early childhood teachers mediates the relationship between the professional learning environment of institutions and their intention to accept artificial intelligence (AI) technology, and whether the experience of using smart and digital devices moderates the effect of science teaching attitude. Methods: An online survey was conducted targeting 118 teachers with more than 1 year of experience in kindergarten and day care center settings. Descriptive statistical analysis, correlation analysis, and The Process macro model 4, 14 were performed using SPSS 27.0 and The Process macro 3.5. Results: First, the science teaching attitude of early childhood teachers served as a mediator between the professional learning environment of institutions and teachers' intention to accept AI technology. Second, the experience of using smart and digital devices was found to moderate the effect of teachers' science teaching attitude on their intention to accept AI technology. Conclusion/Implications: This results showed that an institutional environment that supports teachers' professionalism development and provides rich experience is crucial for promoting teachers' active acceptance of AI technology. The findings highlight the importance of creating a supportive institutional envionment for teacher's professional growth, enhancing science teaching attitudes, and facilitating the use of various devices.

• Journal of the Korean Society of Food Culture
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• v.30 no.2
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• pp.182-189
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• 2015

This study assessed the effect of color marketing in the RTD coffee industry in Korea. In order to investigate the effect of color marketing, this study measured the characteristics of color marketing as well as brand image and attitude in accordance with behavioral intention to purchase. Data were collected using questionnaires, and a total of 310 questionnaires were distributed with 298 entered for data analysis. Frequency analysis, factor analysis, correlation, and multiple regression analysis were tested using SPSS. A total of seven factors were extracted, including brand attitude, purchase intention, association, identification, brand awareness, symbolism, and attention. Significances were found between brand awareness and identification (p<0.001) and attention (p<0.001). In the relationship between characteristics of colors and brand attitude, significances were found in identification (p<0.001), attention (p<0.001), and association (p<0.001). Further, brand attitude and brand awareness had a significant positive effect on purchasing intention of RTD coffee. Results of this study suggested that color marketing is a good marketing tool to persuade potential consumers to purchase RTD coffee based on brand attitude and brand awareness.