• Textile Coloration and Finishing
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• v.13 no.5
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• pp.58-58
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• 2001

This study surveys the fiber behavior in yarn formation and the physical properties of Solo-spun yarn. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier. The physical properties such as yarn count, evenness, strength, and breaking elongation of these yarns were compared with the properties of ring spun yarns and analysed with the mechanism of Solo-spun yarn formation. The grooves on the surface of Solo-spun roller divide the web and interfere the twist propagation. These phenomena cause the uneven draft and the fly of fiber, so the Solo-spun yarn becomes finer than fing-spun yarn and the yarn breaking strength and elongation deteriorate, but these demerits can be improved with rounding the protruded edge of Solo-spun roller grooves.

• Textile Coloration and Finishing
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• v.13 no.5
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• pp.346-352
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• 2001

This study surveys the fiber behavior in yam formation and the physical properties of Solo-spun yam. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier. The physical properties such as yam count, evenness, strength, and breaking elongation of these yams were compared with the properties of ring spun yams and analysed with the mechanism of Solo-spun yarn formation. The grooves on the surface of Solo-spun roller divide the web and interfere the twist propagation. These phenomena cause the uneven draft and the fly of fiber, so the Solo-spun yam becomes finer than fing-spun yam and the yam breaking strength and elongation deteriorate, but these demerits can be improved with rounding the protruded edge of Solo-spun roller grooves.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.1
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• pp.115-129
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• 2010

As the fixed mobile communication tools using the internet are developed, the off-line services are serviced through on-line on the internet. our society is divided into the real world and the cyber world. In the cyber world, the authentication to the user is absolutely required. The authentication is divided into the real-name authentication and the anonymous authentication by the kind of the internet service provider. There are some ISPs needed the real-name authentication and there are others ISPs needed the anonymity authentication. The research about the anonymity authentication is steadily established to these days. In this paper, we analyze the problem about blind signature, group signature, ring signature, and traceable signature. And we propose a method of anonymity authentication using the public certificate. In the proposal, the anonymity certificate have the new structure and management. Certificate Authority issues several anonymity certificates to a user through the real-name authentication. Several anonymity certificates give non-linked and non-traceability to the attacker.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.35-42
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• 2008

This study introduces a robust feature detector for sonar data from a general fixed-type of sonar ring. The detector is composed of a data association filter and a feature extractor. The data association filter removes false returns provided frequently from sonar sensors, and classifies set of data from various objects and robot positions into a group in which all the data are from the same object. The feature extractor calculates the geometries of the feature for the group. We show the possibility of extracting circle feature as well as a line and a point features. The proposed method was applied to a real home environment with a real robot.

• Bulletin of the Korean Mathematical Society
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• v.44 no.2
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• pp.233-239
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• 2007

Let $\mathbb{A}=\mathbb{F}_q$[T] be the polynomial ring over a finite field $\mathbb{F}_q$[T] and K=$\mathbb{F}_q$(T) its field of fractions. Let ${\ell}$ be a fixed prime divisor of q-1. Let J be a finite set of monic irreducible polynomials $P{\in}{\mathbb{A}}$ with deg $P{\equiv}0$ (mod ${\ell})$. In this paper we define the group $C_K$ of circular units in K=k$(\{\sqrt[{\ell}]P\;:\;P{\in}J\})$ in the sense of Kucera [4] and compute the index of $C_K$ in the full unit group $O^*_K$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.1005-1009
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• 2010

This paper presents a digitally-controlled filter calibration technique for biquad RC filter using self oscillation. The biquad RC filter is converted to a fully-differential ring oscillator by changing its resistor connections, where the oscillation frequency reflects the cut-off frequency. The proposed calibration circuit measures the oscillation frequency by counting with a fixed higher-frequency clock and then tunes it to a desired frequency with a digital frequency-locked loop including a PI controller. Because the proposed circuit directly measures the cut-off frequency of the filter itself and calibrates it with the small area digital circuits, the area and the power consumption are much small compared with conventional works. When it is implemented in a 65nm CMOS process, the calibration circuit except the filter consumes the area of 80um X 50um and power consumption is 443uA at 1.2 V supply voltage.

• The Monthly Technology and Standards
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• s.12
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• pp.67-78
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• 2003

In order to keep a characteristic corrugated fibreboard of fruits and flowers, temperature and humidity change of corrugated fibreboard are analyzed. According to relative humidity rises at fixed temperature, bursting strength of corrugated fibreboard was fallen and double wall corrugated fibreboard appeared greatly the bursting strength decline rate than double faced corrugated fibreboard and edgewise compressive strength of paper more than humidity 80% in rapidly fall. A column crush test of paper became decrease in the high temperature and ordinary temperature strength did over humidity 70% rapidly fallen and strength decrease happened by low temperature 80% slowly fallen and later rapidly. According to ISO standard temperature humidity conditioning (23$\pm$2 , 50$\pm$2%) change, pulp composition difference as to the ring crush strength of a physical strength and generally compare to KS standard increased 5∼8% for the compressive strength, and wet strength reagent was increased 4% inside and out.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.942-949
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• 2014

We studied about the rotor design change using a Ferrite ring magnet to reduce material cost in the condition of the same stator core design. However, this design direction has many weak points such as the decrease of BEMF, the low maximum output, the irreversible demagnetization characteristics of a permanent magnet and so on. In order to mitigate such disadvantages, an optimization design of the BLDC motor has been developed by changing each design parameter and by improving the electromagnetic structure. In the proposed water pump SPM BLDC motor using Ferrite magnet, the outer and inner diameter of stator is fixed to the value of the conventional IPM BLDC motor using Nd-Fe-B magnet. The design specification requirements should be satisfied with the same output power and efficiency characteristics in the same dimension. As a result of this study, the design comparison results considering driving performances and material cost are represented. Through the actual experiment with the prototype of the designed motor, the simulations results are verified.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.360-366
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• 2001

This paper show the designing, manufacturing and performance test procedure of a high speed, fixed ratio planetary roller type traction drive as a speed reducer. The arrangement and size design for sun roller, planetary rollers and ring roller are carried out and a proper pre-load mechanism are adopted. To improve transmitting power capacity and endurance limit, nitro-carburized bearing steel and a synthetic traction oil are used. The manufactured and assembled traction drive operated successfully under unloaded conditions. Further tests for various load and speed conditions are executing now to improve the performance of the traction drive.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.4
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• pp.31-36
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• 2005

This paper describes a research work on the die design for the deep drawing & ironing(D. D. I) of high pressure gas cylinder. D. D. I die set is large-sized die used in horizontal press, which is usually composed of a drawing, and an ironing die. Design method of D. D. I die set is very different from that of conventional cold forging die set. Outer diameter of the die set is fixed because of press specification and that of the insert should be as small as possible for saving material cost. In this study, D. D. I die set has been designed to consider those characteristics, and the feasibility of the designed die has been verified by FE-analysis. In addition, the automated system of die design has been developed in AutoCAD R14 by formulating the applied methods to the regular rules.