• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.125-133
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• 2002

The purpose of this study was to develop a method for estimating 3-D coordinates of lower trunk muscles using orientation angles during a motion. Traditional 3-D motion analysis system with DLT technique was used to track down the locations of eight reference markers which were attached on the back of the subject. In order to estimate the orientations of individual lumbar vertebrae and musculoskeletal parameters of the lower trunk muscle, the rotation matrix of the middle trunk reference frame relative to the lower trunk reference frame was determined and the angular locations of individual lumbar vertebrae were estimated by partitioning the orientation angles (Cardan angles) that represent the relative angles between the rotations of the middle and lower trunks. When the orientation angles of individual intervertebral joints were known at a given instant, the instantaneous coordinates of the origin and insertion for all selected muscles relative to the L5 local reference frame were obtained by applying the transformation matrix to the original coordinates which were relative to a local reference frame (S1, L4, L3, L2, or L1) in a rotation sequence about the Z-, X- and Y-axes. The multiplication of transformation matrices was performed to estimate the geometry and kinematics of all selected muscles. The time histories of the 3-D coordinates of the origin and insertion of all selected muscles relative to the center of the L4-L5 motion segment were determined for each trial.

• Journal of the Korean Ceramic Society
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• v.32 no.3
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• pp.305-312
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• 1995

Thin films of Pb(Mg, Zn)1/3Nb2/3O3 were fabricated by spin coating the Pb-Mg-Zn-Nb-O complex alkoxide sols on(111) Pt-coated MgO (100) planes. It was observed that the content of H2O and the rheological characteristics of sol greatly influenced the orientation of perovskite grains after thin-film formation. A strong preferential orientation of (100)-type planes of the perovskite grains was obtained for the sol aged for 15 days with the molar ratio of H2O to total metal alkoxides=2. As small angle X-ray scattering experiment in the Porod region was performed to correlate the observed preferential orientation with the network structure of precursors at various stage of aging. It was shown that the degree of branching of the Pb-Mg-Zn-Nb-O precursor chain had a direct effect on the preferred oreintation, and weakly branched precursor systems led to highly oriented grains after thin-film formation.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.36-48
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• 2007

This paper proposed 3D keyframe animation using orientation interpolator. 3D keyframe animation consists of a number of transform nodes that have geometrical node of initial model and several interpolator nodes that represent the object moving. In the proposed algorithm, we randomly selects transform nodes with orientation interpolator node and performs to resample quaternion components for haying uniform key time. And then, watermark bits are embedded into quaternion components with large rotation angles. Experimental results verified that the watermark embedded by the proposed algorithm had good robustness against geometrical attacks and timeline attacks and also PSNR of keyvalue in orientation interpolator node is above 42dB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1915-1923
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• 2011

For automated guidance control of a magnetically guided-all wheel steered vehicle, it is necessary to have information about position and orientation of the vehicle, and deviations from the reference path in real time. The magnet reference system considered here consists of three magnetic sensors mounted on the vehicle and magnetic markers, which are non-equidistantly buried in the road. This paper presents an observer to estimate such position and orientation at the center of gravity of the vehicle. This algorithm is based on the simple kinematic model of vehicle and uses the data of wheel velocity, steering angle, and the discrete measurements of marker positions. Since this algorithm requires the exact values of initial states, we have also proposed an algorithm of determining the initial position and orientation from the 16 successive magnet pole data, which are given by the magnetic measurement system(MMS). The proposed algorithm is capable of continuing to estimate for the case that the magnetic sensor fail to measure up to three successive magnets. It is shown through experimental data that the proposed algorithm works well within permissible error range.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.18-21
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• 2003

Fused Deposition Modeling (FDM) parts are made by piling up thin layers that cause the stair stepping effect at the surface of FDM parts. This effect brings about poor surface roughness of the part and requires additional post machining such as manual finishing that is detrimental to the part geometry and time consuming. Determining optimal build orientation for FDM parts can be one solution to minimize the post machining. However, by using the CAD model, calculating the optimal build orientation is impractical due to heavy computing process. In order to calculate the optimal build orientation with high speed. the surface roughness model based on measured data and interpolation is newly developed in this research. Also. the genetic algorithm (GA) is applied for acquiring reliable solution. Finally, It is verified from the test that the presented approach is very efficient for reducing the additional post machining process fer FDM parts.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.403-407
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• 2013

Fouett$\acute{e}$ turns are repeated pirouettes which begin as a normal pirouette en dehors but include a movement that allows the rotational momentum lost to friction to be regained once each revolution. The purpose of this study was to investigate on orientation density of head/trunk to the front with and without music to which dancers perform the Fouette turn in time. 10 female dancers($21.0{\pm}1.4$ years old, height; $165.3{\pm}3.9$ cm, weight: $50.5{\pm}5.7$ kg) who are the students of S University participated in this study. It took shorter time to perform one revolution of fouette turn with music (930 ms) than without music (961 ms), which reason may be the shorter time of phase 2 in which the rotational momentum is not produced but lost to fiction. Orientation density of trunk to the front was smaller with music (.176) than without music (.196), while the one of head had not significant difference between with and without music. And the path length of marker on $2^{nd}$ left metatarsal bone during one revolution was smaller with music (35.7 cm) than without music (40.2 cm) but the difference was not statistically significant (p=.267).

• Korean Journal of Human Ecology
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• v.24 no.6
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• pp.741-753
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• 2015

The purpose of this study was to investigate whether elementary children's time-use and self-regulated learning ability was different according to gender and whether children's gender and time-use effects self-regulated learning ability. Participants were 2,122 children who participated in KCYPS longitudinal study from their first grade to third grade. Time-use was reported by children's parents. Children's self-regulated learning is invented by Yang(2000). Components of self-regulated learning scale was achievement value, mastery goal orientation, action control, academic time management. The major findings were as follows. First, children's self-regulated learning was different according to chidren's gender. Girls' achievement value, mastery goal orientation, academic time management scores were higher than the boys'. Second, children's daily time was different according to their gender. Third, children's daily time-use affected their self-regulated leaning, however children's gender didn't.

• Journal of the Korean Home Economics Association
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• v.31 no.3
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• pp.1-13
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• 1993

This study examined the expenditure on time-saving services and related variables. The time-saving services are food away from home, delivery food, dry cleaning, clothing care, helper and total service. The specific objectives of this study were: (1) to investigate the differences in the expenditure on time saving services according to social economic and demographic variables. (2) to investigate the differences in the expenditure on time-saving services according to role-overload, home goal orientation and work goal orientation. (3) to investigate the independent influence of variables related to the expenditure on time-saving services. For this objectives survey was conducted using interview. The data used in this study included 160 women living in Seoul from employed professional housewives, employed non-professional housewives and non-employed housewives. Statistical analyses were conducted using frequencies, percentiles, mean, oneway ANOVA, DUNCAN-test and multiple regression. The major findings were: (1) Wife's education, wife's age, income, tenure, level of living and employment status were significantly related to the expenditure on time-saving services by using the one-way ANOVA. (2) Income, education, level of living, number of children, and employment status explained the variance of the expenditures on time-saving services about 20%-39% by using a multiple regression method.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.74-74
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• 2002

This paper describes a corner matching technique for automatic relative orientation. Automatically matched corner points from stereo aerial images are used to a data set and help to improve automation of relative orientation process. A general corner matching process of overall image to image has very heavy operation and repetitive computation, so very time-consuming. But aerial stereo images are approximately seventy percent overlapped and little rotated. Based this hypothesis, we designed a sectional corner matching technique calculating correlation section by section between stereo images. Although the overlap information is not accurate, if we know it approximately, the matching process can be lighter. Since the size of aerial image is very large, corner extraction process is performed hierarchically by creating image pyramid, and corners extracted are refined at the higher level image. Extracted corners at the final step are matched section by section. Matched corners are filtered using positional information and their relation and distribution. Filtering process is applied over several steps because the thing affecting to get good result-good relative orientation parameter- is not the number of matched corner points but the accuracy of them. Filtered data is filtered one more during the process calculating relative orientation parameters. When the process is finished, we can get the well matched corner points and the refined Von-Gruber areas besides relative orientation parameters. This sectional corner matching technique is efficient by decreasing unnecessarily repetitive operations and contributes to improve automation for relative orientation.

• Journal of Industrial Convergence
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• v.18 no.6
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• pp.119-127
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• 2020

This study was conducted to confirm the effectiveness of the simulation-based orientation program for students preparing for clinical practice in child nursing for the first time. A quasi-experimental non-equivalent control group, pre-posttest design was used. The subjects were 70 3rd grade nursing students who started clinical practice. The simulation-based orientation was applied to 35 students in the experimental group, and the existing lecture style orientation was applied to 35 students in the control group. Data collection was conducted on the nursing competence, perceived stress, self-efficacy, and communication skills before and after orientation. The collected data were analyzed using the SPSS WIN 23.0 program. As a result of the study, the simulation-based orientation program before child nursing practice of nursing college students was found to improve nursing competence (t=5.390, p<.001). Perceived stress, self-efficacy, and communication skills all increased after practice, but were not statistically significant. Therefore, it is necessary to fully consider the situation of students when constructing and operating the contents of the simulation-based orientation.