• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.28-35
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• 2009

This paper derives the equation of coordinated attitude formulation taking into account the orbital dynamics of a target vehicle and the attitude of a tracking satellite in geostationary orbit. The coordinated attitude is always to communicate with the ground station during the target tracking. Because the tracking satellite could perform high angle maneuver, MRP parameters having no singular point are used. Also for the sequential tracking of several target vehicles, the equation automatically making a coordinated attitude is suggested. Coordinated attitude flying and sequential tracking are confirmed through simulations. In short, this paper shows that a satellite could track a target vehicle and communicate with ground station simultaneously using the derived equation of coordinated attitude even though without a accuracy sensor.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.207-214
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• 2009

The purpose of this study was to examine the influence of hypoxic exercise at head down tilt (HDT) on cardiovascular responses. Eight men ($23{\pm}2$ yrs, $176{\pm}4$ cm, and $75{\pm}8$ kg) underwent four separate exercise testing sessions; seated normoxia (SN), seated hypoxia (SH), HDT normoxia (HN), and HDT hypoxia (HH). Each participant performed the leg cycling at predetermined 40% of maximal aerobic capacity relevant to each posture for 15 min. Heart rate was higher in SH than SN and higher also in HH than SH (p<0.05). Blood oxygen saturation was lower in SH than SN (p<0.05). During resting, diastolic blood pressure and mean arterial pressure was significantly lower in HDT than seated posture (p<0.05). No differences were found between conditions in hemoglobin and hematocrit and electrolytes including, sodium, potassium, and chloride. Lactate was higher in SH than SN. In conclusion, there was no effect for cardiovascular responses to duplicate stimuli both hypoxia and posture.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.374-375
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• 2015

Modern people is generated as musculoskeletal diseases due to incorrect posture and habit. In the case of persistent abnormal posture outbreak inconvenient to musculoskeletal diseases in daily life. musculoskeletal diseases, which began as fatigue, pain, sensory paralysis, convulsions are developed symptoms of movement disorders, depression, deformities, etc. In this paper, the unrestrained abnormal posture and habit of occurring in the seat life, have implemented a system which can be determined in less unconscious way. By placing eight pressure sensors in the seat part, determines the posture over the distribution of the weight, it is possible to determine one normal posture and eight abnormal posture that occurs frequently in daily life. To evaluate the performance of the implemented system, the attitude determination experiment was performed. The results confirmed the high performance of 97%.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.293-300
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• 2011

This study was to find out the effect of cervical and thoracic stretching and strengthening exercise program on forward head posture. 32 adults had forward head posture were selected as the subjects for the study. The training program of the exercise group(n=16) consist of postural education with exercise program, subjects in the control group(n=16) participated in a postural education only. Postural measurements of Craniovertebral Angle(CVA) and Cranial Rotation Angle(CRA) were obtained from the using x-ray and PACS(Picture Archiving and Communications System) ${\pi}view^{TM}$. The results were compared with change of CVA and CRA exercise group were significant(p<.05) compared to the control group. However CRA of contol group was significant(P<.05). Also, there were no significant difference(p>.05) between groups on any pre-test measure. however there were significant difference(p<.05) between groups on CVA and CRA post-test measure. This study showed that cervical and thoracic stretching and strengthening exercise program can improve spinal posture alignment for decreasing forward head posture in subjects. These results can be fundamental data for further development of exercise program in interventions of postural improvement.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.67-75
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• 2002

The purpose of this study is to assess the ability of balance control in virtual moving surround stimulation using head mount display (HMD) device and force platform in patients with brain injury. Fifteen patients with stroke (mean age 54.47 yrs) and fifteen healthy normal persons participated. COP parameters were obtained total path distance, frequency of anterior-posterior and medial-lateral component by FFT analysis, weight-spectrum analysis in the two different conditions; (1) during comfortable standing with opened or closed eyes, (2) during virtual moving surround stimulation delivered using HMD with four different moving pattern. Moving patterns consisted of close-far, superior-inferior lilting (pitch) , right-left tilting (roll) and horizontal rotation (yaw) movement. In all parameters, the test-retest reliability was high. Also, the construct validity of virtual moving surround stimulation was excellent (p＜0.05). A posturographic balance assessment system equiped with virtual moving surround stimulation using HMD is considered clinically useful in evaluation of balance control in patients with brain injury.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.298-307
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• 2016

Attitude determination of satellite is categorized by deterministic and recursive method. The recursive algorithm using Kalman filter is widely used. Cubesat has limitation for payload to minimize then only two attitude sensors are installed which are sun sensor and magnetometer. Sun sensor measurements are useless during eclipse, however cubesat keeps estimating attitude to complete the successful mission. In this paper, Attitude determination algorithm based on Kalman filter is developed by additional term which considering the dynamics for SNUSAT-1 with disturbance torque. Verification of attitude accuracy of the algorithm is conducted during eclipse. Attitude determination algorithm is simulated to compare the performance between typical method and proposed algorithm. In addition, Attitude errors are analysed with various magnitude of disturbance torque caused by space environment.

• Science of Emotion and Sensibility
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• v.8 no.1
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• pp.29-36
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• 2005

This study investigated which recumbent posture can give rise to the highest vagal modulation in patients with coronary artery disease(CAD), among three recumbent postures; namely, the supine, left lateral, and right lateral postures. For this purpose, 43 patients as CAD group and 31 patients as control group were studied. Heart rate variability(HRV) was measured on these patients for three recumbent postures in random order Normalized high-frequency power was the highest, whereas normalized low-frequency power was the lowest in the right lateral postures, among the three recumbent postures.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.793-798
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• 2010

In this paper we propose a low-power walking compensation method for biped robot based on consumption energy analysis. Firstly, basic walking motions that can reduce energy consumption of robot movements are implemented based on consumption energy analysis according to robot axes. We define knee bent motion as a basic walking motion. It can improve energy consumption and motion stability by lowering center of gravity of the biped robot. We analyze consumption energy of left and right leg of the robot using motor currents and propose a compensation method of walking motions to reduce unbalance of consumption energy between left leg and right leg. It can also improve energy consumption and walking stability of the robot. The proposed low-power compensation method based on consumption energy analysis is verified by walking experiments of a small biped robot with an embedded system.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.81-86
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• 2020

The Purpose of this study is analysis characteristic of grasping power with each different shoulder horizontal angle. Twenty female university students with no shoulder dysfuction participated subject in three different positions of shoulder horizontal flexion with standing posture, shoulder 0° flexion, elbow 90° flexion, forearm 90° pronation, different positions is followed : shoulder 0° horizontal adduction shoulder 40° horizontal adduction, shoulder 40° horizontal abduction. The One-way repeated ANOVA test was used to determine the different in grip strength on three shoulder horizontal positions. On the average, in the hand grip strength, the horizontal neutral position is higher than horizontal adduction position with significant value. In particular, shoulder horizontal aduction was measured lowest grip strength between three positions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2579-2585
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• 2010

This paper proposes a dynamic human pose tracking method using motion-based search strategy from an image sequence obtained from a monocular camera. The proposed method compares the image features between 3D human model projections and real input images. The method repeats the process until predefined criteria and then estimates 3D human pose that generates the best match. When searching for the best matching configuration with respect to the input image, the search region is determined from the estimated 2D image motion and then search is performed randomly for the body configuration conducted within that search region. As the 2D image motion is highly constrained, this significantly reduces the dimensionality of the feasible space. This strategy have two advantages: the motion estimation leads to an efficient allocation of the search space, and the pose estimation method is adaptive to various kinds of motion.