• Asia pacific journal of information systems
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• 제10권3호
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• pp.159-180
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• 2000

As the importance of electronic commerce(EC) increases, some people argue that traditional commerce(TC) will ultimately give way to EC in the near future. Regardless of the type of commerce, however, it is the value factors of the customer that would formulate the direction of change in the market. This study investigates the influence of those value factors upon the attitude towards the type commerce and the repurchase intention of products and service. It also addresses the impact of the customer's risk disposition and level of confidence. A number of customer's value factors are hypothesized to affect the attitude, and the attitude in turn is expected to be related to the repurchase intention. Based on two hundred and ninety responses from the computer survey, the hypotheses are tested. The convenience, cost reduction, and information satisfaction factors affect EC attitude and repurchase intention. Similarly, the reliability, personal interaction, and shopping enjoyment factors affect TC attitude and repurchase intention. The comparison between EC and TC factors indicates the significant difference in the time saving factor in favor of EC. The personal characteristics such as risk disposition and level of confidence also influence the attitude and repurchase intention. The implications and limitations of this study are discussed. The value factors identified in this study may serve as important checklists for those firms already in EC and those intending to enter the market.

• Journal of Astronomy and Space Sciences
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• 제26권1호
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• pp.47-58
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• 2009

In this study, a Hardware-In-the-Loop (HIL) simulator using thrusters is developed to validate the spacecraft attitude system. To control the attitude of the simulator, eight cold gas thrusters are aligned with roll, pitch and yaw axis. Also linear actuators are applied to the HIL simulator for automatic mass balancing to compensate the center of mass offset from the center of rotation. The HIL simulator consists of an embedded computer (Onboard PC) for simulator system control, a wireless adapter for wireless network, a rate gyro sensor to measure 3-axis attitude of the simulator, an inclinometer to measure horizontal attitude, and a battery set to supply power for the simulator independently. For the performance test of the HIL simulator, a bang-bang controller and Pulse-Width Pulse-Frequency (PWPF) modulator are evaluated successfully. The maneuver of 68 deg. in yaw axis is tested for the comparison of the both controllers. The settling time of the bang -bang controller is faster than that of the PWPF modulator by six seconds in the experiment. The required fuel of the PWPF modulator is used as much as 51% of bang-bang controller in the experiment. Overall, the HIL simulator is appropriately developed to validate the control algorithms using thrusters.

• 동서간호학연구지
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• 제14권1호
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• pp.24-35
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• 2008

Purpose: The study were to identify smoking knowledge, attitude on smoking and experience of smoking cessation in male smokers. Methods: The subjects were 174 male smoker in Seoul and Inchun. The data were collected using structured questionnaires from 18th of December in 2007 to 16th of March in 2008. The data were analyzed by descriptive statistics and Pearson's Correlation Coefficient with SPSS computer program. The tools were used with smoking knowledge, smoking attitude and experience of smoking cessation. Result: Participants showed that a high level of smoking knowledge score 48.20 (${\pm}5.27$) of total 57. Participants showed that a high level of score 40.80 (${\pm}6.81$) of total 60. There was a positive correlation between smoking attitude and smoking knowledge (r=.319 p=.000). Conclusion: These results suggested that the level of smoking knowledge was related to the level of smoking attitude. Therefore, these finding give useful information for constructing a smoking cessation program in male smokers.

• 문화기술의 융합
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• 제5권3호
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• pp.257-262
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• 2019

최근 드론 같은 무인 이동체에 대한 관심과 일상생활에 활용이 늘어나면서 많은 다양한 분야에서 이를 이용하는 응용 사례가 급속도로 확산되고 있다. 하지만 이러한 무인 이동체는 쉽게 외부 환경 요인으로 인한 균형 이탈이나 추락 등의 사고로 이어질 수 있는 많은 위험 요인을 내포하고 있다. 이러한 무인 이동체의 안전한 운용을 위하여 안정적인 자세 제어 알고리즘은 매우 중요한 부분을 차지하고 있으며 현재 널리 사용되고 있는 PID 제어 알고리즘은 거의 완벽한 단계의 자세 제어 기술을 선보이고 있다. 본 연구에서는 기존의 자세 제어 방법과는 달리 보다 외부 환경적인 요인으로 부터 안정적이고 지속적인 자세 제어를 할 수 있는 퍼지 로직을 기반으로 하는 스마트 자세 제어 알고리즘을 제안하고 모의실험을 통하여 기존의 방법과 그 성능을 비교 분석하고자 한다.

• International journal of advanced smart convergence
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• 제9권1호
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• pp.1-9
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• 2020

This study was conducted to investigate the effects of computer attitudes such as anxiety, confidence, preference, usefulness, and computer literacy on their critical thinking ability, targeting college students at unspecified university universities. The period of data collection was from January 10, 2020 to January 17, 2020. A total of 213 people participated in the study. For data analysis, SPSS 18.0 was used for frequency analysis, Pearson correlation, x2 square, and simple regression analysis. As a result of the analysis, the difference of interests under the statistical significance level among general characteristics was Gender (x²=55.7^***, p<0.001), Age (x²=407.5^***, p<0.001), Resident (x²=127.5^***, p<0.001) Family (x²=289.4^***, p<0.001). In the simple regression analysis, computer liking (t=2.102, p<0.05) and computer use ability affected Truth seeking (t=-6.319, p<0.01), computer use ability was affecting analyticity (t=-5.630, p<0.01), computer use ability was affecting systematicity (t=-2.545, p<0.05), computer use ability was affecting maturity under statistical significance (t=-2.583, p<0.05). In conclusion, this study suggests that computer liking and computer use ability affect the sub-factor components of critical thinking disposition, truth seeking, analyticity, systematicity, and maturity, therefore the emphasis of this study is to emphasize that it is desirable to use the computer as a medium of learning based on computer literacy rather than worrying about excessive computer use.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1283-1288
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• 2003

This paper proposes an approach to attitude control artificial satellites with jet-engine. The jet-engine produces on-off thrust, which can be modelled as pulse-width-modulated (PWM) function. Therefore, the problem is converted to design a PWM controller and we develop an efficient technique for this purpose using digital redesign. The digital redesign is a converting technique a well-designed analog controller into the equivalent digital one maintaining the property of the original analog control system in the sense of state-matching. The redesigned digital controller is again converted into PWM controller using the equivalent area principle. We show a computer simulation of the attitude control of artificial satellites.

• 제어로봇시스템학회논문지
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• 제8권4호
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• pp.313-318
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• 2002

A robust attitude controller using Lyapunov redesign technique for spacecraft is proposed. In this controller, qua- ternion feedback is considered to have the attitude maneuver capability very close to the eigen-axis rotation. The controller consists of three parts: the nominal feedback parts which is a PD-type controller for the nominal system without uncertainties, the additional term compensating for the gyroscopic motion, and the third part for ensuring robustness to uncertainties. Lyapunov stability criteria is applied to stability analysis. The performance of the proposed controller is demonstrated via computer simulation.

• 전기학회논문지
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• 제67권7호
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• pp.871-877
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• 2018

In this paper, we propose a triple nested PID control scheme for stable hovering of a quadrotor and propose a complementary filter based sensor fusion technique to improve the performance of attitude, altitude and velocity measurement. The triple nested controller has a structure in which a double nested attitude controller that has the angular velocity PD controller in inner loop and the angular PI controller in outer loop, is nested in a velocity control loop to enable stable hovering even in the case of disturbance. We also propose a sensor fusion technique by applying a complementary filter in order to reduce the noise and drift error included in the acceleration and gyro sensor and to measure the velocity by fusing image, gyro, and acceleration sensor. In order to verity the performance, we applied the proposed control and measurement scheme to hovering control of quadrotor.

• 한국군사과학기술학회지
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• 제4권2호
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• pp.147-156
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• 2001

In this paper, a robust attitude control scheme based on Eigenaxis rotation for the spacecraft is proposed. Eigenaxis rotation transforms the attitude of spacecraft to the shortest path and is represented by quaternion. The control law consists of PD-type control part for the nominal system and the robust control part for compensating inertia uncertainty. For the proposed controller, stability analysis is performed and the performance is shown via computer simulation.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.675-684
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• 2004

The Helicopter system has a non-linearity and complexity. Futhermore, because of absence of its correct mathematical model. it is difficult to control accurately its attitudes for elevation angle and azimuth one. Therefore, we proposed a GA-PID control technique to control these angles efficiently. The proposed GA-PID controller can systematically generate optimal PID parameters by applying GA theory to a helicopter attitude control system. Through the computer simulation, the GA-PID technique shows better attitude control characteristic than traditional PID control technique.