• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.9
• /
• pp.1259-1265
• /
• 2014

In this paper, the real-time attitude determination based Matlab using low-cost receivers was designed and evaluated. The GNSS attitude determination system was implemented to operation in real-time by TimerCallback in MATLAB. The TTM(Transmission Time Misalignment) of U-blox receiver was confirmed through zero baseline tests and this problem was revised. The computed attitude by the high-cost NovAtel receiver was compared to the computed attitude by the low-cost U-blox receiver. As a result of this, the performance of attitude determination systems by low-cost receiver was confirmed. To determine baseline, LAMBDA and BC-LAMBDA for integer ambiguities search methods were used. To confirm suitable integer ambiguity search method in real-time attitude determination algorithm, determined baselines by two methods were compared, and it was confirmed that BC-LAMBDA is more suitable. As a result of this, the operation of real-time attitude determination system was confirmed using 3 low-cost receivers.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.1
• /
• pp.44-50
• /
• 2009

In this study, the relationship between military pilot's spatial ability and unusual attitude recovery was investigate. MRT(Mental Rotation Test) was measured with spatial ability whereas recovery time and error rates were mearsured with respect to 11 unusual attitudes. Eight fighter pilots and eight rear cockpit pilots of F-4E participated in this study. The results showed that MRT response time was significantly correlated with unusual attitude recovery time. The regression equation showed that unusual attitude recovery time was linearly related to MRT response time and could be explained by MRT response time more than 66%. In conclusion, it is recommended that a training is needed to improve the mental rotation ability in a visually restricted environments during maneuvering.

• The Research Journal of the Costume Culture
• /
• v.28 no.6
• /
• pp.875-889
• /
• 2020

This study examined the effect of Instagram usage time (short, long) and spending on fashion products (light, heavy) on product attitude and purchase intention of products promoted by an influencer. The moderating effect of influencer type (mega, macro, micro) was also investigated. A total of 515 males and females in their 20s participated in an online survey. Descriptive statistics were analyzed and exploratory factor analysis and two-way ANOVA were conducted. Research findings were as follows. First, the usage time, both short and long, had a positive effect on product attitude. Also, the interactive effects of usage time and influencer type on product attitude were found. Consumers with short Instagram usage time displayed the highest attitude toward products promoted by a macro-influencer whereas consumers with long Instagram usage time displayed the highest attitude toward products promoted by a micro-influencer. Second, usage time and influencer type did not show interactive effects on purchase intention. Third, both categoriacl variables of users' spending on fashion products had a positive effect on product attitude. Fourth, the interaction effects of spending on fashion products and influencer types on purchase intention were found. The group of light buyers showed the highest purchase intention on products promoted by the macro-influencer while the group of heavy buyers showed the highest purchase intention of products promoted by the micro-influencer. Based on the results, implications were suggested.

• The Research Journal of the Costume Culture
• /
• v.24 no.1
• /
• pp.13-26
• /
• 2016

The purpose of the present study is to investigate the effect of time remaining to use mileage in the notification message from retailers on consumer responses. A total of 577 consumers participated in experiments involving different notification messages of the time remaining to use mileage. Results showed: 1) a significant difference in mileage benefit perception, positive emotion, negative emotion, attitude toward retailers, and repurchase intention according to the remaining time to use mileages, 2) benefit perception positively affected positive emotion and negatively affected negative emotion; positive emotion positively affected and negative emotion negatively affected attitude toward retailers; and attitude positively affected repurchase intention on retailers, and 3) the remaining time to use mileages moderates the relationship between attitude and repurchase intention. Findings highlighted the importance of timing of the message to notify the consumer as to remaining time to use mileage. In the case of a message indicating long remaining time to use mileage, consumers showed more positive responses toward retailers than did consumers who had a message indicating short remaining time to use mileage. These results can be used as guidelines to select the optimal time to send notification messages of remaining time to use mileage in order to generate positive consumer responses.

• International Journal of Aeronautical and Space Sciences
• /
• v.8 no.2
• /
• pp.17-27
• /
• 2007

Minimum-time attitude maneuvers of three-axis stabilized spacecraft are presented to study the feasibility of using three magnetic torquers perform large angle maneuvers. Previous applications of magnetic torquers have been limited to spin-stabilized satellites or supplemental actuators of three axis stabilized satellites because of the capability of magnetic torquers to produce torques about a specific axes. The minimum-time attitude maneuver problem is solved by applying a parameter optimization method for orbital cases to verify that the magnetic torque system can perform as required. Direct collocation and a nonlinear programming method with a constraining method by Simpson's rule are used to convert the minimum-time maneuver problems into parameter optimization problems. An appropriate number of nodes is presented to find a bang-bang type solution to the minimum-time problem. Some modifications in the boundary conditions of final attitude are made to solve the problem more robustly and efficiently. The numerical studies illustrate that the presented method can provide a capable and robust attitude reorientation by using only magnetic torquers. However, the required maneuver times are relatively longer than when thrusters or wheels are used. Performance of the system in the presence of errors in the magnetometer as well as the geomagnetic field model still good.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.271-275
• /
• 2006

This paper describes the design and realization of full attitude system based on MEMS IMU and GPS carrier phase. The work can be divided into two parts: First, initial heading is determined by using two GPS receivers. And this paper discusses the usage of space geometry conditions to reduce the range of ambiguity search. The method presented in this paper was tested on the static. On the static condition, an accuracy better than 0.06 degrees for heading for 3.48m long baseline has been achieved. Integration of GPS and low cost MEMS IMU are used to realize the real-time heading attitude system. Second, level attitude (pitch and roll) is determined using the method of frequency-velocity for the feedback control. At the same time, the method using the attitude based on MEMS IMU to help determination of the range of ambiguity search is proposed. The results done on the sea show that an alternative means to provide real-time, cost-effective, accurate and reliable attitude information for attitude surveys. Though motivated by a big ships application, the design can be applied to other vehicles.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.4
• /
• pp.381-388
• /
• 2014

In this paper, the attitude of a quadrotor system is controlled by a time-delayed control method which uses the previous information to cancel out uncertainties in the system. Although the linear controller works for the attitude control, the robust performance against disturbance is relatively poor. Therefore, a time-delayed controller as a robust controller is used. Experimental studies are conducted to validate the performance by the time-delayed control method. The performances of both a linear controller and a time-delayed controller are compared.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.2
• /
• pp.265-272
• /
• 1996

In this paper, attitude computation algorithm for a strap down ARS(Attitude Reference System)of an underwater vehicle has been studied. Attitude errors o the ARS using low-level gyroscopes tend to increase with time due to gyroscope errors. To cope with this problem, a mixing algorithm of accelerometer aided attitude computation has been developed. The algorithm can successfully bound the error increase for cruising motion, but it gives instantaneously large errors when a vehicle maneuvers. To improve the performance in case of vehicle's maneuver, a new attitude computation mixing algorithm complying state of vehicle and to manage the adjustment of the gains which are invariant in the existing algorithm. In addition, a gain scheduling method is applied to fuzzy inference composition process for real-time computation. Monte Carlo simulation results show that the proposed algorithm provides better performance than the existing algorithm.

• Journal of the Korean Home Economics Association
• /
• v.29 no.3
• /
• pp.209-226
• /
• 1991

This study aimed at providing the basic data for the measurement of the attitude for socialization of household work by analysis of the attitude for socialization of houselhold work according to demographic variables, the degree of acceptance for living change. This study was composed of the attitude for the socialization of household work was based on time, quality, cost factor. The results of this study were as follows: 1. The attitude for socialization of household work was influenced by sex, age, marriage, sex $\times$ marriage and the degree of acceptance for living change. 2. The variables which affected the attitude for socialization of household work independently had influence on it in the following order : the degree of acceptance for living change, sex, house type. 3. The result of path analysis had confirmed that sex, age, income marriage, house type variable indirectly influenced the attitude for socialization of household work through the degree of acceptance for living change. Sex, and marriage variable directly influenced on the attitude for socialization of household work. Through the this study. The attitude for socialization of houselhold work was influnced by the degree of acceptance for living change. Change of household work is socialization of household work and right attitude to the socialization fof household work is necessary for satisfaction of variouse needs. for saving of time and money through the socialization of household work.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.1984-1986
• /
• 2001

In order to provided continuous solutions, latest developing navigation systems tend to integrate GPS receiver with INS or DR. Using the GPS carrier-phase measurements, an attitude GPS receiver with three antennas obtain the 3-dimensional attitude such as roll, pitch, and heading as well as position and velocity. With these angle measurements, in the attitude GPS/INS integrated system, attitude or gyro errors can be directly compensated. In this paper, we develop an integrated navigation system that combines attitude GPS receiver with INS. The performance of real-time integrated navigation system is determined by not only the implements of integration filter but also the synchronization of measurements. To meet these real-time requirements, the navigation software is implemented in multi-tasking structure in this paper. We also employ time-synchronization technique in the multi-sensor fusion. Experimental results show that the performance of the attitude GPS/INS integrated system is consistent even when cycle-slip occurs in carrier-phase measurements.