• Journal of Fashion Business
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• v.14 no.2
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• pp.57-72
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• 2010

The purposes of the research were to find out the clothing construction factors of the mechanical industry working clothes by analyzing the working clothes supplied to 5 subject companies; and to suggest the optimized sewing conditions and the seam strength and elongation experimental data according to the clothing material and seam types implied to the working clothes collected. The fabric types and trimmings used for the mechanical manufacturing working clothes were Polyester/Cotton(65/35%), Polyester/Rayon(65/35%), Cotton(100%); and linings, interlining, various fastenings etc. 2 stitch types, i.e. lock and two-thread chain stitches were applied to the construction of the flat, lap felled, French, superimposed, lapped and bound seams for the seam strength and elongation experiment. The results derived from the experiment were as follows. (1) The seam strength results according to the seam types were high in the order of lap felled>lapped>flat, superimposed and French seams. (2) Considering the features of the seam construction, as the number of fabric layers at the seam line increased the seam strength also increased. (3) Apart from the highest seam strength from the experiment using the net lining with the main fabric, the seam construction consisting of two fabric layers with the interlining showed relatively high seam strength results. (4) The seam elongations according to the stitch types were high in the order of two-thread chain>lock stitches.

• Journal of the Korea Society of Computer and Information
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• v.20 no.3
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• pp.89-96
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• 2015

IT is widely used for biomechanics and AHRS sensor also be highlighted with small sized characteristics and price competitiveness in the field of motion measurement and analysis of sports. In this paper, we attach the AHRS to the figure skate shoes to measure the motion data like spin, forward/backward, jump, in/out edge and toe movement. In order to reduce the measurement error, we have adopted the sensors equipped with Madgwick complementary filtering and also use Euler angle to quaternion conversion to reduce the Gimbal-lock effect. We test and experiment the accuracy and execution time of the pattern recognition algorithms like PCA, ICA, LDA, SVM to show the recognition possibility of it on the basic motions of figure skating from the 9-axis trajectory information which is gathered from AHRS sensor. From the result, PCA, ICA have low accuracy, but LDA, SVM have good accuracy to use for recognition of basic motions of figure skating.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.811-818
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• 2016

A continuous fine-tuning phase locked loop with an additional negative feedback loop has been proposed. When the phase locked loop is out-of-lock, the phase locked loop has a fast locking characteristic using the continuous band-selection loop. When the phase locked loop is near in-lock, the bandwidth is narrowed with the fine loop. The additional negative feedback loop consists of a voltage controlled oscillator, a frequency voltage converter and its internal loop filter. It serves a negative feedback function to the main phase locked loop, and improves the phase noise characteristics and the stability of the proposed phase locked loop. The additional negative feedback loop makes the continuous fine-tuning loop work stably without any voltage fluctuation in the loop filter. Measurement results of the fabricated phase locked loop in $0.18{\mu}m$ CMOS process show that the phase noise is -109.6dBc/Hz at 2MHz offset from 742.8MHz carrier frequency.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.4 s.247
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• pp.298-305
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• 2006

The flow around a circular cylinder which oscillates rotationally with a relatively high forcing frequency has been investigated experimentally using flow visualization and hot-wire measurements. Dominant parameters are Reynolds number (Re), oscillation amplitude $({\theta}_A)$, and frequency ratio $F_R=f_f/f_n$, where $f_f$ is the forcing frequency and $f_n$ is the natural frequency of vortex shedding. Experiments were carried out under the conditions of $Re=4.14{\times}10^3,\;{\theta}_A={\pi}/6$, and $0{\leq}F_R{\leq}2$. The effect of frequency ratio $F_R$ on the flow structure of wake was evaluated by measuring wake velocity profile and spectral analysis of hot-wire signal. Depending on the frequency ratio $F_R$, the cylinder wake has 5 different flow regimes. The vortex formation length and vortex shedding frequency are changed significantly before and after the lock-on regime. The drag coefficient was reduced under the condition of $F_R<1.0$ and the maximum drag reduction is about 33% at $F_R=0.8$. However, the drag is increased as $F_R$ increases beyond $F_R=1.0$. This active flow control method can be effective in aerodynamic applications, if the forcing parameters are selected optimally.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.25-35
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• 2002

Many multimedia presentation applications involve retrieval of objects from more than one collaborating server. Presentations of objects from different collaborating servers might be interdependent. This implies that objects should be retrieved from remote servers and delivered continuously according to given time constraints. Such applications need an estimate of the avaliable network resources to each of the collaborating servers and local system resources in order to identify a schedule for retrieving the objects composing the presentation. A collaborating server can suggest modifications of the retrieval schedule depending on its load. these modifications can potentially affect the retrieval schedule for other collaborating applications. Hence, a sequence of negotiations has to be carried out with the collaborating servers in order to commit for a retrieval schedule of the objects composing the presentation. In this paper, we propose an application sub-layer protocol, RLCP(Resource Lock Commit Protocol), for handling the negotiation and commitment of the resources required for a collaborative multimedia presentation and apply it to distributed video presentation application.

• Journal of Korean Society of Forest Science
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• v.97 no.1
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• pp.61-70
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• 2008

This study was conducted to develop a mobile tower-yarder with tractor for agriculture and forestry that is the efficient yarder in steep terrains, thinning operation and small scale logging operation. It was designed and manufactured that the power source of tower-yarder is equiped three hydraulic pump connected to PTO of tractor, and three hydraulic pump is used to operate the four motor for drum, the cylinder for clutch of interlocker, the cylinder for tower expanding and the out-rigger cylinder. It was to adopt the running skyline system and the inter-lock function, and to equip the double capstan drum, the storage drum and the clutch for interlock in the development of tower-yarder. It was to develop the tower-yarder which the winch torque of double-capstan drum, the traction force of double-capstan drum, the number of rotation of double-capstan drum and the line speed is $191kg{\cdot}m$, 1,910 kgf, 220.5 rpm and 138.5 m/min, respectively. And it was known that the optimum flange diameter of the main and haulback storage drum is about 360 mm and about 460 mm in order to storage the main line length of 250m and the haulback line length of 450 m. The carriage was made to adopt the running skyline system and to equip the lock function in order to the convenience of chocking and the fall down preventing of tree. It was provided to develop the wire remote controller for the inter-lock function, the convenience of control and the efficiency of yarding. In development process, this tower-yarder was attached the 3-point linkage hitch equipment and the tire wheel for the traction and moving of tower-yarder. Also, it was equipped that the out-rigger and the guy line in order to raise the safety and efficiency of yarding of tower-yarder.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.548-552
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• 2003

In the braking system, the friction force is the most important factor of the design. For long time, many researchers have been strived for getting the exact friction coefficients. But the friction coefficients are affected by the road condition and changed by lots of parameters, such as normal force and characteristics between two contacted materials, temperature, etc. For the development of ABS of the aircraft, HILS(Hardware-In-the-Loop-Simulation) test and dynamometer test was carried out. For the calculation of the friction coefficients, the wheel moments were measured using the load cell mounted on the housing of the wheel. The test conditions were dry and greasy, as the 0.7 and 0.4 in friction coefficient, respectively. In this paper, the test results of the friction coefficients were represented and the improvement method was suggested.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.26-29
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• 2017

We studied the distribution of the current density and its magnetic-field dependence in GdBCO coated conductors with AC bias currents using low temperature scanning Hall probe microscopy. We selectively measured magnetic field profiles from AC signal obtained by Lock-in technique and calculated current distributions by inversion calculation. In order to confirm the AC measurement results, we applied DC current corresponding to RMS value of AC current and compared distribution of AC and DC transport current. We carried out the same measurements at various external DC magnetic fields, and investigated field dependence of AC current distribution. We notice that the AC current distribution unaffected by external magnetic fields and preserved their own path on the contrary to DC current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.122-122
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• 2009

최근 PC의 성능이 향상되면서, 고성능의 전원공급 장치가 요구되고 있다. 특히 CPU에 대전력을 공급하는 싱크로너스 벅 컨버터는 파워 MOSFET을 구동하기 위해 별도의 구동 IC가 필요하다. 본 논문은 adaptive 지연을 이용하여 파워 MOSFET을 구동하는 싱크로너스 벅 구동 IC를 설계하였다. 고정밀도의 밴드캡 기준회로와 비교기를 이용하여 30 ns의 adaptive 지연을 생성하며, 전력소모를 줄이기 위해 저전압에서 동작하는 UVLO(under voltage lock out)를 설계하였다. 또한 상단 파워 MOSFET을 구동하기 위하여 부트스트랩 방식을 이용하며, 부트스트랩 다이오드를 IC 내부에 내장하여 컨버터의 설계비용을 줄였다. 설계한 구동 IC의 동작 전압 범위는 8 V - 15 V이며, 출력 전류는 최대 2A이다. 싱크로너스 벅 구동 IC는 $0.5\;{\mu}m$ BiCMOS(Bipolar-CMOS) 공정 파라미터를 사용하여 설계되었으며, 시뮬레이션은 Cadence사의 Spectre를 이용하였다.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.974-979
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• 2004

The fluidic muscle cylinder consist of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. In this study, we carried out the finite element modelling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.