• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.60-63
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• 2009

In this letter we report on the carrier velocity of polycrystalline pentacene transistors as a function of electric field. We performed a series of measurements on devices with a range of channel lengths. At moderate electric fields (<$5{\times}10^5$ V/cm), the characteristics are similar to those of disordered or amorphous organic semiconductors. The highest velocities we have measured are near $6{\times}10^4$ cm/s at room temperature. We perform quasi-static and dynamic measurements to measure carrier velocity. These results fill an important void between experimental results that have been obtained with disordered/amorphous organic semiconductors and single crystals.

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.191-198
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• 2005

The static and dynamic rheological behavior of concentrated sodium dodecylsulfate (SDS) stabilized, deformability controllable polydimethylsiloxane (PDMS) emulsions is reported and comparisons made with silica (hard sphere) suspensions. Steady-mode measurements indicate 'hard' (viscoelastic) droplets behave as hard spheres, while 'soft' (viscous) droplets induce structural flexibility of the emulsion against shear. Dynamic-mode measurements reveal that viscoelasticity of droplets provides the great magnitude of elasticity for the 'hard' emulsion, while formation of planar films between droplets is the origin of the elasticity of 'soft' emulsions. Combination of steady and dynamic rheological behavior has enabled depiction of droplet structure evolution in relation to the shear stress applied, especially by taking advantage of the normal force that reflects the transient deformation of droplets.

• Wind and Structures
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• v.21 no.4
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• pp.383-405
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• 2015

This study investigated aerodynamic characteristics of an inclined square prism experimentally. Pressure measurements were performed on a static square prism with a series of inclinations including forward inclinations (inclined to the upwind direction) and backward inclinations (inclined to the downwind direction). The prism with a vertical attitude was also tested for comparisons. Based on the pressure data, influences of the inclinations on aerodynamic characteristics (e.g., force coefficients, pressure distributions on the surfaces, and vortex shedding features) of the square prism were evaluated in detail. The results show that the inclinations have significant effects on these aerodynamic characteristics. Furthermore, the influences of the forward and backward inclinations are quite different.

• ETRI Journal
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• v.43 no.4
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• pp.594-602
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• 2021

Recently, quantitative and repetitive inspections of the old urban area were conducted because many structures exceed their designed lifetime. The health of a building can be validated from the condition of the outer wall, while the slant angle of the wall widely serves as an indicator of urban regeneration projects. Mostly, the inspector directly measures the inclination of the wall or partially uses 3D point measurements using a static light detection and ranging (LiDAR). These approaches are costly, time-consuming, and only limited space can be measured. Therefore, we propose a mobile mapping system and automatic slant map generation algorithm, configured to capture urban environments online. Additionally, we use the LiDAR-inertial mapping algorithm to construct raw point clouds with gravity information. The proposed method extracts walls from raw point clouds and measures the slant angle of walls accurately. The generated slant angle map is evaluated in indoor and outdoor environments, and the accuracy is compared with real tiltmeter measurements.

• Structural Engineering and Mechanics
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• v.52 no.1
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• pp.149-172
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• 2014

Four algorithms for damage detection of trusses are presented in this paper. These approaches can detect damage by using both complete and incomplete measurements. The suggested methods are based on the minimization of the difference between the measured and analytical static responses of structures. A non-linear constrained optimization problem is established to estimate the severity and location of damage. To reach the responses, the successive quadratic method is used. Based on the objective function, the stiffness matrix of the truss should be estimated and inverted in the optimization procedure. The differences of the proposed techniques are rooted in the strategy utilized for inverting the stiffness matrix of the damaged structure. Additionally, for separating the probable damaged members, a new formulation is proposed. This scheme is employed prior to the outset of the optimization process. Furthermore, a new tactic is presented to select the appropriate load pattern. To investigate the robustness and efficiency of the authors' method, several numerical tests are performed. Moreover, Monte Carlo simulation is carried out to assess the effect of noisy measurements on the estimated parameters.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.3_4
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• pp.509-520
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• 2004

The aim of this study was to provide the basic 2-dimensional statistics requisite in the siting system and design of gloves. The 64 static measurements were selected to provide information about hands. Participants in the study were 824 adults, aged between 18 and 64. Subjects were divided into four age groups: 18 to 29, 30 to 39, 40 to 49, and 50 to 64, and separated according to sex. Statistical tests such as Descriptive Analysis, and Anova were conducted to analyze the data and ascertain the differences among the ages. The disparities between sex groups were compared by T-test. In addition, correlation among the 57 measurements was analyzed and the results were compared to the data from Japanese and other studies. The results indicated that all the measurements were significantly larger in the male group. There were significant differences among age groups for most hand circumferences, breadths and thickness items. As the age increased, the hand circumferences, breadths and thickness items became wider and thicker. In addition, as the age increased, the mean measurement value of the length items decreased, so that it became shorter. Hand length was highly correlated with finger length, palm length and height. Maximum hand circumference II was highly correlated with hand circumferences, hand breadth and weight.

• Corrosion Science and Technology
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• v.17 no.6
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• pp.310-316
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• 2018

The effect of passive film on corrosion of metals and alloys in a static corrosive environment has been studied by many researchers and is well known, however few studies have been conducted on the electrochemical measurement of metals and alloys during cavitation corrosion conditions, and there are no test standards for electrochemical measurements 'During cavitation' conditions. This study used commercially additive manufactured(AM) pure titanium in tests of anodic polarization, corrosion potential measurements, AC impedance measurements, and repassivation. Tests were performed in 3.5% NaCl solution under three conditions, 'No cavitation', 'After cavitation', and 'During cavitation' condition. When cavitation corrosion occurred, the passive current density was greatly increased, the corrosion potential largely lowered, and the passive film revealed a small polarization resistance. The current fluctuation by the passivation and repassivation phenomena was measured first, and this behavior was repeatedly generated at a very high speed. The electrochemical corrosion mechanism that occurred during cavitation corrosion was based on result of the electrochemical properties 'No cavitation', 'After cavitation', and 'During cavitation' conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.02a
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• pp.62-70
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• 1999

Artesian pressure exists in Yangsan site, the maximum value of which has been measured as high as 5 t/m$^2$. This paper deals with the prediction of consolidation settlement for the site with artesian pressure. The consolidation settlement at the site has been accelerated using vertical band drains. Since the artesian pressure gives lower effective stress than a static condition, its effect should be considered in the settlement prediction. This case study shows that the prediction of settlement and pore pressure dissipation agrees well with the measurements, when considering the artesian effect.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.792-796
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• 1992

Readings from robotic sensors are somewhat uncertain. This uncertainty problem makes it difficult to employ the sensor feedback controlled robots widely in real industrial sites, In this paper, redundant sensor fusion techniques are discussed to effectively overcome the sensor uncertainty, A weighted averaging technique is proposed under static and dynamic sensing environments. Proposed technique is tested by the experiments of stereoscopic 3d position measurements.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.3
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• pp.222-231
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• 1982

A single free jet formed by the interaction of two curved wall jets on a Cylinder surface is defined as "the Coanda nozzle jet" in this study. In order to investigate the characteristics of Coanda nozzle jet, an experimental analysis was carried out; measurements of the static pressure distribution on the cylinder surface, the mean velocity profile, the turbulence intensity, and the Reynolds shear stress by using x-type hot-wire probe.ire probe.