• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.207-214
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• 2009

This study proposed an advanced warning information system based on real-time traffic conflict analysis. An algorithm to detect and analyze unsafe traffic events associated with car-following and lane-changes using individual vehicle trajectories was developed. A positive guidance procedure was adopted to provide warning information to alert drivers to hazardous traffic conditions derived from the outcomes of the algorithm. In addition, autoregressive integrated moving average (ARIMA) analyses were conducted to investigate the predictability of warning information for the enhancement of information reliability.

• Journal of Korean Academy of Nursing
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• v.40 no.3
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• pp.307-316
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• 2010

Purpose: The purpose of this study was to identify the levels of relocation stress syndrome (RSS) and influencing the stress experienced by Intensive Care Unit (ICU) patients just after transfer to general wards. Methods: A cross-sectional study was conducted with 257 patients who transferred from the intensive care unit. Data were collected through self-report questionnaires from May to October, 2009. Data were analyzed using the Pearson correlation coefficient, t-test, one-way ANOVA, and stepwise multiple linear regression with SPSS/WIN 12.0. Results: The mean score for RSS was $17.80{\pm}9.16$. The factors predicting relocation stress syndrome were symptom experience, differences in scope and quality of care provided by ICU and ward nursing staffs, satisfaction with transfer process, length of stay in ICU and economic status, and these factors explained 40% of relocation stress syndrome (F=31.61, p<.001). Conclusion: By understanding the stress experienced by ICU patients, nurses are better able to provide psychological support and thus more holistic care to critically ill patients. Further research is needed to consider the impact of relocation stress syndrome on patients' health outcomes in the recovery trajectory.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.210-217
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• 2014

This paper presents experimental studies on controlling one-wheel robot, GYROBO. The previous one has the problem of falling down because the inside gimbal leans against one direction to make it balancing. This structural problem has been solved by redesigning the system. Gains obtained through experimental tasks are used as a gain scheduling method so that GYROBO is more stabilized. A line trajectory following control task is performed to test the driving control as well.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.1-7
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• 2011

This paper presents implementation and control of a two wheeled mobile robot system which consists of two systems, an inverted pendulum system and a mobile robot system. Control purpose is to regulate its balancing and navigation. The balancing robot has advantages of one point turning and robust balancing against disturbances from the ground. Simulation studies of local and global control methods are performed. Since the robot is implemented to have a symmetrical structure, simple linear control algorithms are used for balancing and navigation. Low cost sensors such as gyro and tilt sensor are fused together to detect the inclined angle. Experimental studies of following desired circular trajectory are conducted.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.243-249
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• 2015

In direct vehicle teleoperation, a human operator drives a vehicle at a distance through a pair of master and slave device. However, if there is time delay, it is difficult to remotely drive the vehicle due to slow response. In order to address this problem, we introduced a novel methodology of shared vehicle teleoperation using a virtual driving interface. The methodology was developed with four components: 1) virtual driving environment, 2) interface for virtual driving environment, 3) path generator based on virtual driving trajectory, 4) path following controller. Experimental results showed the effectiveness of the proposed approach in simple and cluttered driving environment as well. In the experiments, we compared two sampling methods, fixed sampling time and user defined instant, and finally merged method showed best remote driving performance in term of completion time and number of collision.

• Phonetics and Speech Sciences
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• v.4 no.1
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• pp.21-28
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• 2012

Many previous studies reported acoustic parameters of English vowels produced by a clear speaking style. In everyday usage, we actually produce speech sounds with various speaking styles. Different styles may yield different acoustic measurements. This study attempts to examine pitch and formant trajectories of eleven English vowels produced by nine American males in order to understand acoustic variations depending on clear and conversational speaking styles. The author used Praat to obtain trajectories systematically at seven equidistant time points over the vowel segment while checking measurement validity. Results showed that pitch trajectories indicated distinct patterns depending on four speaking styles. Generally, higher pitch values were observed in the higher vowels and the pitch was higher in the clear speaking styles than that in the conversational styles. The same trend was observed in the three formant trajectories of front vowels and the first formant trajectories of back vowels. The second and third trajectories of back vowels revealed an opposite or inconsistent trend, which might be attributable to the coarticulation of the following consonant or lip rounding gestures. The author made a tentative conclusion that people tend to produce vowels to enhance pitch and formant differences to transmit their information clearly. Further perceptual studies on synthesized vowels with varying pitch and formant values are desirable to address the conclusion.

• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.285-292
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• 2016

For articulated swimming robots, there have been no researches about controlling the motion or trajectory following. A control method for articulated swimming robot is suggested by extending a previous algorithm, ESPG (Extended Swimming Pattern Generator). The control method focuses on the situation that continuous pre-determined swimming pattern is applied for long range travelling. In previous studies, there has not been a way to control the propulsive force when a swimming pattern created by ESPG was in progress. Hence, no control could be made unless the swimming pattern was completed even though an error occurred while the swimming pattern was in progress. In order to solve this problem, this study analyzes swimming patterns and suggests a method to control the propulsive force even while the swimming pattern was in progress. The angular velocity of each link is influenced and this eventually modifies the propulsive force. However, The angular velocity is changed, a number of problems can occur. In order to resolve this issue, phase compensation method and synchronization method were suggested. A simple controller was designed to confirm whether the suggested methods are able to control and a simulation has affirmed it. Moreover, it was applied to CALEB 10 (a biomimetic underwater articulated robot) and the result was verified.

• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.242-250
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• 1989

The performance of a vertical type centrifugal distributor of granular materials was studied by means of mathematical models and experimental investigations. To develop the mathematical description of particle motion, some assumptions were made. The distribution process consisted of three stages: the entrance of a particle to the blade, the motion of the particle on the blade, and the motion of the particle in the air. The physical properties of fertilizer, which affected the particle motion, were investigated: bluk density, coefficient of friction, coefficient of restitution, and particle size distribution. The particle motion were simulated by using a computer. A prototype distributor was designed and constructed for experimental tests. The following conclusions were drawn from the computer simulation and experiment results. 1. The fertilizer may slide or roll at the point of contact when they impact on the blade and move along the blade. 2. The interaction among fertilizers may prevent them from bouncing. 3. When fertilizers roll on the blade, rolling resistance is one of the factors affecting the particle's motion. 4. The trajectory angle and position of fertilizers from a disc depend on the blade position and particle shape, but the rotating speed of the disc affected them only slightly.

• Smart Structures and Systems
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• v.5 no.3
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• pp.209-221
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• 2009

A control algorithm for seismic protection of building structures based on the theory of variable structural control or sliding mode control is presented. The paper focus in the design of sliding surface. A method for determining the sliding surface by pole assignment algorithm where the poles of the system in the sliding surface are obtained on-line, based on the frequency content of the incoming earthquake signal applied to the structure, is proposed. The proposed algorithm consists of the following steps: (i) On-line FFT process is applied to the incoming part of the signal and its frequency content is recognized. (ii) A transformation of the frequency content to the complex plane is performed and the desired location of poles of the controlled structure on the sliding surface is estimated. (iii) Based on the estimated poles the sliding surface is obtained. (iv) Then, the control force which will drive the response trajectory into the estimated sliding surface and force it to stay there all the subsequent time is obtained using Lyapunov stability theory. The above steps are repeated continuously for the entire duration of the incoming earthquake. The potential applications and the effectiveness of the improved control algorithm are demonstrated by numerical examples. The simulation results indicate that the response of a structure is reduced significantly compared to the response of the uncontrolled structure, while the required control demand is achievable.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.774-779
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• 2010

This paper analyzes the fundamental dynamic motion of a robotic arm and body mechanism on the platform of a mobile manipulation system. For the purpose, we reveal the dynamic coefficients of a robotic arm and body mechanism, and identify their dominant behaviors in an exemplar trajectory following simulation. We also discuss on their influence for the motion of the body, shoulder, and elbow joints. It is finally expected that this analysis is helpful for effective manipulation tasks by using mobile manipulation systems with an arm and body mechanism.