• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.261-261
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• 2000

This paper analyzes the characteristics of pre-sliding friction of an X-Y table of CNC machining center at velocity reversal, and presents a simple and effective method of friction compensation based on this characteristics. At velocity reversal, a large position tracking error occurs because of the discontinuous change of friction. The relationship between the occurrence time of maximum position tracking error and the acceleration at zero velocity is analyzed by using the spring-like friction model. Furthermore, the experimental observation verifies this relation. From this, the state transition tine from pre-sliding regime into sliding regime can be predicted. Using the predicted transition time, the friction can be effectively compensated and table experimental results show its effectiveness.

• 한국의류산업학회지
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• 제6권6호
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• pp.765-771
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• 2004

This study surveys the warp and weft tension differences among 3 types of rapier looms and analyses the mechanical properties of worsted fabrics for garment with relation of these looms characteristics using KES-FB system. Raper is divided by two parts. In the 1st paper, the worsted fabric is woven as 5 harness satin weave using 1/40 Nm sirofil worsted warp yam and 1/30 Nm worsted weft yam by rapier looms such as FAST-R, THEMA-11-E and PICANOL-GTX respectively. The weavability is also analysed by measuring warp tension variation according to the warp position and weft tension of 3 kinds of looms. The relationship between shed amount and the warp tension is surveyed, and the relationship between end breaks and warp and weft tensions is also discussed.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2005년도 춘계학술발표대회 논문집
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• pp.159-163
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• 2005

The purpose of this study was to analyze the relationship between the product characteristics and spatial configuration in a retail store. This study utilized the analytical method of Space Syntax, and the software package used for the analysis was New-wave and Pesh. The qualitative study focused on the showroom of 'H INTERIOR', a leading furniture company in Korea, and examined the accessibility of the space. The result showed that the main accessible route was well established in the retail store, and more trendy and fashionable products were likely to be displayed in more accessible places. Also, the products in the selected showroom were arranged according to the pricing information, so that products with lower price were displayed in more accessible places. This study suggested that it be important to adequately and appropriately display the products in relation to the characteristics of products, and implied that the method of Space Syntax was useful to strategically evaluate the display in retail spaces.

• Communications for Statistical Applications and Methods
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• 제28권6호
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• pp.583-594
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• 2021

In this paper, we propose wavelet-based procedures to identify the difference between images, including portraits and handwriting. The proposed methods are based on a novel combination of multiscale methods with a regularization technique. The multiscale method extracts the local characteristics of an image, and the distinct features are obtained through the regularized regression of the local characteristics. The regularized regression approach copes with the high-dimensional problem to build the relation between the local characteristics. Lytle and Yang (2006) introduced the detection method of forged handwriting via wavelets and summary statistics. We expand the scope of their method to the general image and significantly improve the results. We demonstrate the promising empirical evidence of the proposed method through various experiments.

• 소음진동
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• 제7권4호
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• pp.689-700
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• 1997

There are many difficulties in designing the engine structure properly due to the strong conflicts between NVH characteristics and the high performance, light weight and low product cost. Many feasible noise reduction techniques should be carefully incorporated to meet such stringent noise requirements. It is also required that the engine development be carried out by introducing concurrent engineering, in which the analysis and test database are usefully applied to the detail designs from the 1st stage. This paper reviews the significance of the noise characteristics of the structure elements in relation to the combustion pressure. The mechanisms of the crank shaft rumbling, which is the main source having the bad influence on the sound quality, are also explained. The influences of dynamic behavior of engine structure on its noise are investigated, followed by discussions on experimental results of the features necessary for the design of low noise engine concepts.

• 한국유체기계학회 논문집
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• 제2권2호
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• pp.74-80
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• 1999

Recently, impressive gains of performance and efficiency with apparently little or no loss in flow range have been seen with the use of LSVD(Low Solidity Vaned Diffuser) over vaneless diffuser. Experiments of the effects of the vane turning angle variations(positive, negative, zero), with the other design parameters fixed, on the performance and flow range were carried out. Diffusers with a zero turning angle have the best characteristics in terms of performance and efficiency and the FFT results show different frequency characteristics due to vane turning angles in low flow range.

• 한국정밀공학회지
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• 제9권1호
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• pp.126-136
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• 1992

In this paper, a simple structured feedback compensation scheme for a electro-hydraulic servo system to keep the response characteristics unchanged regardless of the load variation is proposed. In electro-hydraulic servo system, servovalve is most important control element. But the relation between input corrent and output flowrate of the servovalve has properties as follows; firstly, in spite of constant input current, output flowrate decreases as load pressure increases, secondly, according to frequency response of typical servovalve, the characteristics of gain and phase shift is something like 2'nd order system. Load pressure feedback compensation method has been applied to eliminate the first influence, the second influence has been improved by phase lead compensation method. As a result of above compensation methods, regardless of variation load condition, spring and inertia load, the compensation scheme has been verified to be effective within the range of frequency less than 25Hz by static response and dynamic response in time domain and frequency domain through experiments.

• 소성∙가공
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• 제19권7호
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• pp.416-422
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• 2010

The $\{10\bar{1}2\}$ twinning characteristics, such as active twin variants, volume fraction of twins with strain, twin morphology, twin texture and angle relationship between twins, were dependent on the activation mode (i.e., tension parallel to the caxis or compression perpendicular to the c-axis). The selection criterion of active twin variants was governed by the Schmid law. This activation of selected twin variants depending on the activation mode consequently caused a totally different plastic deformation behavior in two activation modes. The differences in the deformation characteristics, such as flow stress and work hardening rate, between both activation modes were explained in relation with activation stresses for slips and twinning, relative activities of twinning and slips during plastic deformation, grain refining effect by twin boundaries (Hall-Petch effect), and twinning-induced change in activities of slips.

• 한국의류산업학회지
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• 제7권1호
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• pp.101-105
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• 2005

This study surveys the warp and weft tension differences between projectile and air-jet looms and analyses the mechanical properties of worsted fabrics for garment with relation of these loom characteristics using KES-FB system. The paper is divided by two parts. In the 1st paper, the worsted fabric is woven as 5 harness satin weave using 1/40 Nm sirofil worsted warp yarn and 1/30 Nm worsted weft yarn by projectile(Sulzer) and air-jet looms(Picanol PAT and OMNI), respectively. The weavability is also analysed by measuring warp tension variation according to the warp position and weft tension of 3 kinds of looms. The relationship between shed amount and the warp tension is surveyed, and the relationship between end breaks and warp and weft tensions is also discussed.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.569-576
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• 2020

This study investigated the characteristics of microfibril angle(MFA) in order to see if there was any difference in pine tree lumber quality among the three mountain areas surrounding the Taebaek Mountains in Korea - Yeongdong (Goseong-gun), Yeongseo (Hongcheon-gun) and Yeongnam (Bonghwa-gun). Pine trees of each mountain area were divided into earlywood and latewood in relation to heartwood part (1959 ~ 1961, 3 annual rings) and sapwood part (2002 ~ 2004, 3annual rings), and measured at tangential section. The microfibril angle showed significant differences between mountain areas. In general, Goseong Mountain was found to have 37.35°, followed by Hongcheon Mountain 32.42° and Bonghwa Mountain 25.75°, in order. The sapwood part had larger angle than heartwood part; and earlywood, than latewood. Variation within a single annual ring tended to be smaller from earlywood toward latewood.