• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.243-244
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• 2008

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.54.2-54
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• 2001

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.157-158
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• 2007

• Bulletin of the Korean Space Science Society
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• 1995.10a
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• pp.36-36
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• 1995

No Abstract, See Full Text

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.313-314
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• 2011

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.639-651
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• 2018

An analytical solution to generate attitude command profile for agile spacecraft is proposed. In realistic environment, obtaining analytical minimum-time optimal solution is very difficult because of following constraints-: 1) actuator saturation, 2) flexible mode excitation, 3) uplink command bandwidth limit. For that reasons, this paper applies two simplifications, an eigen-axis rotation and a finite-jerk approximated profile, to derive the solution in an analytical manner. The resulting attitude profile can be used as a feedforward or reference input to on-board attitude controller, and it can enhance spacecraft agility. Equations of attitude command profile are derived in two general boundary conditions: rest-to-rest maneuver and spin-to-spin maneuver. Simulation results demonstrate that the initial and final boundary conditions, in terms of time, attitude, and angular velocities, are well satisfied with the proposed analytical solution. The derived attitude command generation algorithm may be used to minimize a number of parameters to be uploaded to spacecraft or to automate a sequence of attitude command generation on-board.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.2
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• pp.127-136
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• 2012

Many research of hand gesture recognition based on vision system have been conducted which enable user operate various electronic devices more easily. 3D position calculation and meaningful gesture classification from similar gestures should be executed to recognize hand gesture accurately. A simple and cost effective method of 3D position calculation and gesture spotting (a task to recognize meaningful gesture from other similar meaningless gestures) is described in this paper. 3D position is achieved by calculation of two cameras relative position through pan/tilt module and a marker regardless with the placed position. Fuzzy garbage model is proposed to provide a variable reference value to decide whether the user gesture is the command gesture or not. The reference is achieved from fuzzy command gesture model and fuzzy garbage model which returns the score that shows the degree of belonging to command gesture and garbage gesture respectively. Two-stage user adaptation is proposed that off-line (batch) adaptation for inter-personal difference and on-line (incremental) adaptation for intra-difference to enhance the performance. Experiment is conducted for 5 different users. The recognition rate of command (discriminate command gesture) is more than 95% when only one command like meaningless gesture exists and more than 85% when the command is mixed with many other similar gestures.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.44-54
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• 2014

This paper suggests two kinds of reaction control system command generation methods for upper stage attitude control of launch vehicles. The reaction control system is assumed to consist of two sets of three nozzles. One operation technology is based on mixed attitude error functions, and the other is based on command mixing functions. Both are compared via simulations. The simulation results show that the latter is comparatively preferable in terms of interference among control axes, independency of controller design and analysis among axes, and prediction of flight performance of each control axis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1034-1041
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• 2014

This paper propose a fuzzy inference model for obstacle avoidance for a mobile robot with an active camera, which is intelligently searching the goal location in unknown environments using command fusion, based on situational command using an vision sensor. Instead of using "physical sensor fusion" method which generates the trajectory of a robot based upon the environment model and sensory data. In this paper, "command fusion" method is used to govern the robot motions. The navigation strategy is based on the combination of fuzzy rules tuned for both goal-approach and obstacle-avoidance. We describe experimental results obtained with the proposed method that demonstrate successful navigation using real vision data.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3831-3836
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• 2013

Background: S100A14 has recently been implicated in the progress of several types of cancers. This study aimed to investigate the clinical significance and possible mechanisms of action of S100A14 in the invasion and metastasis of hepatocellular carcinoma (HCC). Methods: S100A14 expression in HCC was detected at mRNA and protein levels and its prognostic significance was assessed. Functional roles of S100A14 in HCC were investigated using MTT, BrdU, wound healing, transwell invasion assay and HCC metastatic mouse model. Results: S100A14 was significantly elevated in HCC tissues, correlated with multiple tumor nodes, high Edmondson-Steiner grade and vascular invasion. Multivariate Cox analysis showed that the S100A14 expression level was a significant and independent prognostic factor for overall survival (OS) of HCC patients (hazard ratio=1.98, 95% confidence interval=1.14-3.46, P=0.013). S100A14 promoted cell proliferation, invasion and metastasis of HCC in vitro and in vivo. Conclusion: These results suggest S100A14 is a novel prognostic marker and therapeutic target for HCC.