• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.47.2-47.2
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• 2019

We present a kinematic study of the two young OB associations Cygnus OB2 and Carina OB1 using the recently released Gaia astrometric data. The unimodal distributions of parallaxes of stars indicate that these associations are real stellar systems, rather than line-of-sight coincidences. The associations are found to comprise dense star clusters and a sparse halo which have different proper motions. Clusters have small spatial sizes with small dispersions in proper motion, while the haloes extending to tens of parsecs have a large dispersion in proper motion. We speculate that this aspect is related to that found in molecular clouds, the so-called "line width-size" relation. In this talk, the formation process of these associations is discussed, based on our findings.

• Smart Structures and Systems
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• v.20 no.1
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• pp.23-33
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• 2017

Variable Curvature Friction Pendulum (VCFP) bearing is one of the alternatives to control excessive induced responses of isolated structures subjected to near-fault ground motions. The curvature of sliding surface in this isolator is varying with displacement and its function is non-spherical. Selecting the most appropriate function for the sliding surface depends on the design objectives and ground motion characteristics. To date, few polynomial functions have been experimentally tested for VCFP however it needs comprehensive parametric study to find out which one provides the most effective behavior. Herein, seismic performance of the isolated structure mounted on VCFP is investigated with two different polynomial functions of the sliding surface (Order 4 and 6). By variation of the constants in these functions through changing design parameters, 120 cases of isolators are evaluated and the most proper function is explored to minimize floor acceleration and/or isolator displacement under different hazard levels. Beside representing the desire sliding surface with adaptive behavior, it was shown that the polynomial function with order 6 has least possible floor acceleration under seven near-field ground motions in different levels.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.653-656
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• 2005

This paper introduces design, fabrication and experiment process of a novel scanner for the high speed AFM(Atomic Force Microscope). A proper design modification is proposed through analyses on the dynamic characteristics of the existing linear motion stages using a dynamic analysis program, Recurdyn. Since the scanning speed of each direction is allowed to be different, the linear motion stage for the high-speed scanner of AFM can be so designed to have different resonance frequencies for the modes with one dominant displacement in the desired directions. One way to achieve this objective is to use one-direction flexure mechanism for each direction and to mount one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separates the frequencies of the two vibration modes with one dominant displacement in each desired direction, hence, the coupling between the motions in the two directions. In addition, a pair of actuators is used for each axis to decrease the cross talks in the two motions and gives a force large enough to actuate the slow motion stage, which carries the fast motion stage. After these design modifications, a novel scanner with scanning speed higher than 10 Hz can be achieved to realize undistorted images in the high speed AFM.

• Journal of Korean Physical Therapy Science
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• v.8 no.1
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• pp.917-921
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• 2001

The purpose of this study was to examine the difference in measurements of passive range of motion(PROM) of shoulder when motions are assessed in sitting, as compared with supine and the intratester and intertester reliabilities for goniometric measurements of shoulder PROM using two different sizes of goniometers. * A thesis submitted to the committee of Graduate School of Public Health, Chungnam National University in partial fulfillment of the requirements for the degree of Master of Public Health conferred in February 2001. Fifty one adult male subjects were measured three times, in random order, for the six shoulder motions(flexion, extension, abduction, adduction, external rotation, and internal rotation) while sitting and supine by three different therapists. Data were analyzed to determine intraclass correlation coefficients (ICCs) and paired "t" values between trials for measurements with different goniometer and betweensitting and supine trials. There was statistical difference in measurement of shoulder motion between supine and sitting position and no statistical difference in goniometric type. The intratester intraclass correlation coefficients (ICCs) for all motions ranged from .87 to .98. The ICCs for the intertester reliability of PROM measurements of all shoulder motion ranged from .26 to .89. These findings suggest that reliable measures of PROM of the shoulder can be obtained using standard goniometry in a proper position.

• The Research Journal of the Costume Culture
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• v.11 no.3
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• pp.375-386
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• 2003

The purpose of this study is to seek the change of body surface according to cycling motions and to give suggestions to the pattern and spare space between body and wear in each bodily parts to be heavily considered for making the bicycle wear. The cycling motions were analyzed by taking the sequential pictures of cycling covering motion by a digital camera. The experiments with gypsum were toward a woman in her twenties. We draw the line standard of the body's surface, separated their gypsum-replicated fragments of body's surface following the analyses of the change in their lengths. As the motions were made, we decided the degree of the changed length as spare space when compared the erected posture with the cycling posture, presenting the pattern of the cycling wear with the preparation of wears for testing. After that, the essential experiments were conducted toward three cycle players wore our experimental wears. Regards their evaluated appearance, evaluations over three points were obtained from all parameters except the width of front armhole. Accordingly, our experimental wears were remarkably understood as a relatively proper wear as bicycle wear.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.118-123
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• 1999

The mathematical model used in the simulation of ship's maneuvering contains the hydrodynamic coefficients, which are usually evaluated based on PMM model tests in the towing tank and used to predict ship's maneuvering performance when applied to the proto-type ship. The proper mathematical model has to be developed to predict ship's maneuvering motions with hydrodynamic coefficients very well. The mathematical model for PMM model tests is analyzed with identification program and the hydrodynamic coefficients and maneuvering motions by system identification we compared with those obtained directly from PMM model tests and sea trial. The mathematical model for PMM model tests was established and the magnitudes of ship's maneuvering coefficients were determined. When the identified values of coefficients were used to simulate the maneuvers, a very good agreement was obtained between the numerically simulated motion responses and those obtained from PMM model tests.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.22-29
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• 2010

In this study, computational multi-body dynamics and structural vibration analyses including some impact condition have been conducted for the ground flight test system of the developed smart UAV model. Designed ground test system has four degree-of-freedom motions with limited motion control mechanism. Design safety margin designs for several structural components are tested and verified considering expected critical motions (pitching and rolling) of the test smart UAV model. Computational results for various analysis conditions are practically presented in detail. Futhermore, proper design modifications of the initially designed test equipment in order to guarantee or increase structural safety have been successfully conducted in the design stage.

• Journal of Korean Institute of Industrial Engineers
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• v.4 no.1
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• pp.21-27
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• 1978

For labor-intensive sewing industry, productivity could be enhanced with the proper utilization of standard time system. This paper develops a standard data for sewing operations through three stages. The first is to identify the manual motions from sewing operations. The second is to simplify the MTM-1 data considering the frequency and the nature of basic motions occuring in the operations. Finally we synthesize the standard data using the simplified MTM-1 by the film analysis of the actual operations pictured in the field. The standard data developed is shown to be easier and faster with reasonable accuracy in determining the standard time compared to the MTM-1.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.2
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• pp.103-110
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• 2004

This paper proposes a new method on the EMG AR(autoregressive) modeling in pattern recognition for various head motions. The proper electrode placement in applying AR or cepstral coefficients for EMG signature discrimination is investigated. EMG signals are measured for different 10 motions with two electrode arrangements simultaneously. Electrode pairs are located separately on dominant muscles(S-type arrangement), because the bandwidth of signals obtained from S-type placement is wider than that from C-type(closely in the region between muscles). From the result of EMG pattern recognition test, the proposed mIAR(modified integrated mean autoregressive model) technique improves the recognitions rate around 17-21％ compared with other the AR and cepstral methods.

• Bulletin of the Korean Mathematical Society
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• v.53 no.5
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• pp.1411-1425
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• 2016

We provide a partial differential equation for European options on a stock whose price process follows a general geometric Riemannian Brownian motion. The existence and the uniqueness of solutions to the partial differential equation are investigated, and then an expression of the value for European options is obtained using the fundamental solution technique. Proper Riemannian metrics on the real number field can make the distribution of return rates of the stock induced by our model have the character of leptokurtosis and fat-tail; in addition, they can also explain option pricing bias and implied volatility smile (skew).