• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.67-72
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• 2015

This paper proposes an object tracking system based on keypoints using homography in mobile environments. The proposed system is based on markerless tracking, and there are four modules which are recognition, tracking, detecting and learning module. Recognition module detects and identifies an object to be matched on current frame correspond to the database using LSH through SURF, and then this module generates a standard object information. Tracking module tracks an object using homography information that generate by being matched on the learned object keypoints to the current object keypoints. Then update the window included the object for defining object's pose. Detecting module finds out the object based on having the best possible knowledge available among the learned objects information, when the system fails to track. The experimental results show that the proposed system is able to recognize and track objects with updating object's pose for the use of mobile platform.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.73-77
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• 2015

This paper proposes an object tracking system according to reliability assessment of learning in mobile environments. The proposed system is based on markerless tracking, and there are four modules which are recognition, tracking, detecting and learning module. Recognition module detects and identifies an object to be matched on current frame correspond to the database using LSH through SURF, and then this module generates a standard object information that has the best reliability of learning. The standard object information is used for evaluating and learning the object that is successful tracking in tracking module. Detecting module finds out the object based on having the best possible knowledge available among the learned objects information, when the system fails to track. The experimental results show that the proposed system is able to recognize and track the reliable objects with reliability assessment of learning for the use of mobile platform.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2083-2088
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• 2007

Biosensor based on rugate PSi interferometer for the detection of avidin has been described. Rugate PSi fabricated by applying a computer-generated pseudo-sinusoidal current waveform has been prepared for the application as a label-free biosensor based on porous silicon interferometer. The fabrication, optical characterization, and surface derivatization of a rugate PSi has been described. The method to fabricate biotinderivatized rugate PSi has been investigated. The surface and cross sectional morphology of rugate PSi are obtained with SEM. FT-IR spectroscopy is used to characterize the oxidation and functionalization reaction of rugate PSi sample. Binding of the avidin into the biotin-derivatized rugate PSi induces a change in refractive index. A red-shift of reflectivity by 18 nm in the reflectivity spectrum is observed, when the biotin-modified rugate PSi was exposed to a flow of avidin.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.15-20
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• 2014

The fracture analysis of $SiN_x$ layers, which were deposited by low-temperature plasma enhanced chemical vapor deposition (LT-PECVD) and could be used for an encapsulation layer of a flexible organic light emitting display (OLED), was performed by an electrical method. The specimens of metal-insulator-metal (MIM) structure were prepared using Pt and ITO electrodes. We stressed MIM specimen mechanically by bending outward with a bending radius of 15mm repeatedly and measured leakage current through the top and bottom electrodes. We also observed the cracks, were generated on surface, by using optical microscope. Once the cracks were initiated, the leakage current started to flow. As the amount of cracks increased, the leakage current was also increased. By correlating the electrical leakage current in the MIM specimen with the bending times, the amount of cracks in the encapsulation layer, generated during the bending process, was quantitatively estimated and fracture behavior of the encapsulation layer was also closely investigated.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.65-70
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• 2014

This paper is to improve the problem of the LED dimming control system using the conventional PWM and DAC method. The conventional PWM method controls the average current to switch dimming signal. This method generates the flicker when controlling at a low current. In order to solve the problem, this system prevents the flicker with the DAC method. The LED is lit at micro-current flowing in the LED. And offset voltage is generated in the output of the DAC when the DAC output is very low voltage as 0V. This was resolved by the voltage drop of the output voltage to construct a negative offset circuit. In addition, the LED current can't flow as set values because of overheating of FET. In order to solve the problem, the 16 bits ADC in the microprocessor is a more accurate current control receives the LED current in comparison with the set value. Therefore, the LED dimming control system proposed in this paper showed the accurate and reliable more than conventional systems.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.230-235
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• 2010

In this paper, we controlled the deposition rate and reflective index with process conditions that are TCP power, gas flow ratio and bias for optical properties of $SiO_2$ thin film using TCP-CVD equipment. We obtained a excellent $SiO_2$ thin film which has a excellent uniformity (<1 [%]), deposition rate (0.28 [${\mu}m$/ min]) and reflective index (1.4610-1.4621) within 4" wafer with process conditions ($SiH_4:O_2$=50 : 100 [sccm], TCP power 1 [kW], bias 200 [W]) at [$300^{\circ}C$].

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.824-828
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• 2005

In this study the effect of the content of $TiB_2$ on wear properties was investigated. $Cu-TiB_2$ composites have been fabricated by hot extrusion. Sliding wear tests were peformed by a pin-on-disk type wear test machine under dry condition and loads varied with from 20N to 80N at sliding speed 3.5Hz. The test results showed that the wear losses and the friction coefficients decreased with increasing $Cu-TiB_2$ volume fraction and increasing the size of $Cu-TiB_2$ particle. Wear property of $10{\mu}m,\;5 vol\%\; TiB_2$ specimen was excellent all of the wear specimens. It is thought that the increase of plastic flow resistivity due to uniform distribution of $10{\mu}m,\;5 vol\%\; TiB_2$ wear specimen would improve wear property. The worn surface and wear debris were examined by optical microscope and scanning electron microscope.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.127-135
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• 2007

The objective of this study is to analyze the effect of velocity and vorticity on stratified mixture formation in the visualization engine. In order to investigate spray behavior, the pray velocity is obtained through the cross-correlation PIV method, a useful optical diagnostics technology and the vorticity calculated from the spray velocity component. These results elucidated the relationship between vorticity and entropy, which play an important role in the diffusion process for the early injection case and the stratification process for the late injection case. In addition, we quantified the homogeneous diffusion ate of spray using entropy analysis based on Boltzmann's statistical thermodynamics. Using these methods, we discovered that the homogeneous mixture distribution is more effective as a momentum dissipation of surrounding air than that of the spray concentration with a change in the injection timing. We found that the homogenous diffusion rate increased as the injection timing moved to the early intake stroke process, and BTDC $60^{\circ}$ was the most efficient injection timing for the stratified mixture formation during the compression stroke.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.445-448
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• 2011

In this study, the etching characteristics of $Al_2O_3$ thin films were investigated using an ICP (inductively coupled plasma) of $BCl_3$/Ar gas mixture. The etch rate of $Al_2O_3$ thin films as well as the $SiO_2/Al_2O_3$ etch selectivity were measured as functions of $BCl_3$/Ar mixing ratio (0~100% Ar) at a constant gas pressure (10 mTorr), total gas flow rate (40 sccm), input power (800 W) and bias power (100 W). The behavior of the $Al_2O_3$ etch rate was shown to be quite typical for ion-assisted etch processes with a dominant chemical etch pathway. To analyze the etching mechanism using DLP (double langmuir probe), OES (optical emission spectroscopy) and surface analysis using XPS (x-ray photoelectron spectroscopy) were carried out.

• Tribology and Lubricants
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• v.11 no.4
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• pp.28-34
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• 1995

PTFE has good mechanical and chemical stability at wide temperature range, and more over, shows a low value of friction coefficient. On the other hand, it shows cold flow and high wear rate. However, these short comings can be overcome by adding various fillers. In this experiment, PTFE and polyimide powder were mixed into composite and its tribological characteristics was investigated. 100% polyimide was also tested for comparison. The countefface material was a stainless steel (SUS304). Friction and wear tester of ring-on-block type was used at room temperature and under atmosphere. After the wear test, the worn surfaces were examined by optical microscope. The test results show that PTFE-polyimide composite generates. the wear transfer film on both sides of the friction surfaces, and, the friction coefficient and the wear rates are relatively low. 100% polyimide generated little wear transfer films, showed high friction and wear rates, and also showed some problems of vibration and noise. It even damaged the stainless steel countefface. It was concluded that 100% polyimide does not generate transfer film well because its shear resistanbe is high and it stickslips, thus, friction coefficients and wear rates are high. In case of PTFE-polyimide composite, on the other hand, transfer film containing sufficient PTFE adheres and remains on both wear surfaces well enough because PTFE has low shear resistance. Polyimide particles in the composite were proved to be able to bear normal load and does not show stick-slip because they are covered with transfer film containing much PTFE.