• ETRI Journal
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• v.25 no.2
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• pp.101-108
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• 2003

This paper proposes an improved vascular pattern extraction algorithm for person verification applications. The proposed direction-based vascular pattern extraction (DBVPE) algorithm is based on the directional information of vascular patterns. It applies two different filters to the input images: row vascular pattern extraction filter (RVPEF) for effective extraction of the abscissa vascular patterns and column vascular pattern extraction filter (CVPEF) for effective extraction of the ordinate vascular patterns. We use the combined output of both filters to obtain the final hand vascular patterns. Unlike the conventional hand vascular pattern extraction algorithm, the directional extraction approach prevents loss of the vascular pattern connectivity. To validate the DBVPE algorithm, we used a prototype system with a DSP processor. The prototype system shows approximately a three-times better false acceptance rate (FAR) than the conventional single filter algorithm.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.455-464
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• 1994

The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMG signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements.

• KSTLE International Journal
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• v.6 no.2
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• pp.51-57
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• 2005

Surface texturing of tribological applications is an attractive technology of engineered surface. Therefore, reduction of friction is considered to be necessary for improved efficiency of machines. The current study investigated the potential of textured micro-scale grooves on bearing steel flat mated with pin-on-disk. We discuss reducing friction due to the influence of sliding direction at surface pattern. We can indicate lubrication mechanism as a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for the lubrication condition. It was found that the friction coefficient was changed by the surface pattern and sliding direction, even when surface pattern was the same. It was thus verified that micro-scale grooves could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions. The lubrication regime influences the friction coefficient induced by the sliding direction of groove pattern. The friction coefficient depends on a combination of resistance force and hydrodynamic.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.73-94
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• 2003

The purpose of this investigation was to analyze A kinematic analysis of the Kuzushi-arm motion when performing Morote-Seoinage in judo who was 5 females university representative judokas of light weight category in judo, and filmed on video cameras(60field/s). The data of this study digitizied by KWON3D 2.1 program computed the average and standard deviation calculated individual 5 trials with Programing Lab view 6i. From the data analysis & discussion, the following conclusions were drawn : 1) distance variable of attacking hand arm in kuzushi motion Left right(X direction) displacement variable was all of A, B, C pattern with moving left to right and leaning. Strip of displacement variable was ordo. to C(55.6cm), A(53.3cm), B(43.9cm) pattern, C pattern largely leaned to left Front Rear(Y direction) displacement variable was different A($131.3cm{\pm}3.1cm$), B($128.7{\pm}4.0cm$) and C(111.0cm) on ready position, 3 pattern leaned to rear direction. Strip of displacement was order to B(43.4cm), A(41.1cm) and C pattern(28.3cm). Up down(Z direction) displacement variable was all of A, B, C pattern leaned to up in the Kuzushi-phase and leaned to down in the Kake-phase. Strip of displacement was order to A(83.9cm), B(80.4cm), C pattern(71.9cm). 2) Shoulder joint angle variable Flexion and extension Ready position' angle was A($138.3{\pm}4.9^{\circ}$), B($142.9{\pm}3.7^{\circ}$) and C($164.5^{\circ}$) pattern, strip of flexion extension was order to C($80.9^{\circ}$), A($79.9^{\circ}$) and B($39.0^{\circ}$) pattern, greatly C pattern had largely angle change. Adduction and abduction : B and C pattern's angle change were adduction and abduction in the Kuzushi-phase after adduction in the Kake phase, A pattern's angle change was abduction in the Kuzushi-phase after adduction in the Kake phase. internal and external rotation : 3 pattern were internal rotation in the Tsukuri phase and external rotation in the Kake phase. After B and C pattern were external rotation and A pattern was internal rotation. 3) Elbow joint angle variable Flexion and extension 3 pattern's ready position angle were A($142.0{\pm}4.4^{\circ}$), B($123.5{\pm}5.5^{\circ}$) and C($105.5^{\circ}$) and flexion. Strip of flexion extension were order to A($57.9^{\circ}$), C($34.6^{\circ}$) and B($25.2^{\circ}$) pattern.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.7 no.2
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• pp.25-30
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• 2001

Corrugated board is composed of cellulose fibers which are arranged with the same direction as the board manufactured. The direction is classified with machine direction (MD) and cross-machine direction (CD). Therefore, corrugated board is orthotropic material that has totally different strength properties at each direction and especially, at machine direction, the mechanical properties of fiberboard is superior. The compression strength of the corrugated fiberboard boxes is very important information to the manufacturers and the end users. This study was carried out to design the optimum pattern, size, and location of ventilating hole for ventilating container through the finite element analysis. The optimum pattern and location of ventilating and hand hole were vertical oblong, a short distance to the right and left from the center of panel, and center or a short distance to the top of both sides, respectively. We identified the effect on both stress dispersion and stress level from the analysis of redisigned hand hole.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.593-600
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• 2017

This paper analyzes the performances of direction finding, interference cancellation, and beamforming performance by array antenna pattern measurement distance between the center of array antenna and reference emitter. Array antenna is widely adopted for example as wireless communications, radar, and sonar. In order to use array antenna, array antenna pattern must be known and it can be measured in anechoic chamber. However, the size of anechoic chamber is generally limited. So measurement error of array antenna can be occurred and this could effect performance decrease of direction finding, interference cancellation, and beamforming. It is verified by computer simulation that the performances of direction finding, interference cancellation, and beamforming by array antenna pattern measurement distance.

• IE interfaces
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• v.10 no.2
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• pp.109-114
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• 1997

The tread pattern of tire is represented by a great number of design factors, such as groove breadth of circumference direction, breadth direction, rib breadth, block length, kerfs, tread breadth and tread radius, etc. It is not efficient in time and cost to analyze the rolling resistance for a great number of real tread pattern, because It requires lots of pattern forming handwork. In order to optimize tread pattern for rolling resistance, the experiment is planed and analyzed by Taguchi's robust design methods. We identified the important design factors for Rolling Resistance, determined the optimal condition and calculated prediction value which is related. Using the experiment data and the analyzed data, we developed the program which could predict Rolling Resistance. It is expected that time and cost may be reduced in designing and developing new tire tread pattern.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.407-416
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• 2021

An active phased array antennas can not only electrically steer the beam by controlling the weighting of the excitation signal, but can also form a pattern null in the direction of the interference source. The weight of the excitation signal to steer the main beam can be easily calculated based on the position of the radiating element. In addition, the weight of the excited signal for pattern null formation can also be calculated by setting the required radiation pattern and using WLSM(Weighted Least Squares Method). However, in a general wireless communication network environment, the location of the interference source is unknown. Therefore, an adaptive pattern null synthesis is needed. In this paper, it was confirmed that pattern null synthesis according to the required radiation characteristic was possible. And based on this, adaptive pattern null synthesis into the direction of an interference source was studied using a binary search algorithm based on observation area. As a result of conducting a simulation based on the presented technique, it was confirmed that adaptive pattern null forming into the direction of an interference is possible in efficient way.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.2
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• pp.17-23
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• 1972

In this paper, the radiation characteristics of a large circular loop antenna with sinusoidal current distribution is studded in a moving media with a constant velocity much less than the speed of light. The diameter of the circular loop antenna is comparable with or larger than wave length. In studing the radiation characteristics, vector potential for the antenna is derived and relative field pattern is plotted from the vector potentials. Finally the field patterns are compared with those of stationary media. It is found that maximum directivities are shifted to the direction of the velocity of the media, and the field intensities are decreased in that direction and increased in opposite direction by the velocity component paralell to the loop plane. It is also found that the deviations for the pattern are proportional to the velocity of the media, the frequency of the distributed current, the diameter of the loop antenna, and the daviation depends only upon the parallel component of the velocity to the loop plane.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.337-339
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• 2008

As a shock impinges into a vortex of variable strength, complex shock diffraction can occur. Since a vortex has a fixed rotating direction, the shock wave travelling in one direction creates strong asymmetry in the vortex flow field. The process is that first the shock is divided into two parts by the vortex. One part is moving in the adverse direction opposite to the vortex flow which is captured by the vortex center. The other part is moving in the favorable direction, namely, in the direction same as the vortex flow; it is swung around the vortex, accelerating the vortex flow. In this paper we have investigated numerically using ENO scheme how and why the shock-vortex interaction patterns appear so different for different parametric values. Conclusion is that there are three different types of shock-vortex interaction depending on two related parameters: shock Mach number and vortex Mach number. We present a parameter map by which we can discern what type of interaction pattern appears as a shock impinges into a vortex.