• Journal of Sensor Science and Technology
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• v.26 no.6
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• pp.402-407
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• 2017

Characteristics of various material surface plasmon resonance (SPR) chips were investigated in angular interrogation mode and intensity interrogation mode. Among five metals, silver (Ag), gold (Au), copper (Cu), chromium (Cr) and titanium (Ti), three metals, Ag, Au and Cu were paid attention to since their characteristics can be easily analyzed in angular interrogation mode by investigating the change of their reflectance curves according to refractive index change from 1.331 to 1.335. Most of SPR chips with various configurations showed the similar property in angular interrogation mode. The application of the SPR chip made of Ag, Au and Cu or their combinations depends on their reflectance properties. In intensity interrogation mode, the operation range may be limited since the variation of the intensity was not linearly related to refractive index change ranging from 1.331 to 1.335. However, the SPR chip containing high ratio of Ag may be applicable to high sensitive detection due to their sharp reflectance curves in intensity interrogation mode.

• Korean Journal of Computational Design and Engineering
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• v.2 no.3
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• pp.133-141
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• 1997

In the process of car body design, various surfaces are generated from the given boundary curves. Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface or to use the different generation method based on the evaluation results. This capability is very important because the defect of the surface quality detected in the production stage will require the rework of the dies and will cause a big loss in cost and time. A method of surface interrogation using reflection line is introduced. In this paper, We applied reflection mapping to generate reflection lines on the trimmed NURBS surface. Since reflection lines are obtained from reflection mapping that uses simple and physically acceptable mapping algorithm, they can be efficiently used to simulate the reflection test on the real part in the production line.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.392-397
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• 2009

We designed a wavelength interrogation-based surface plasmon resonance (SPR) biosensor to detect avian influenza DNA (AI-DNA). Hybridization reactions between target AI-DNA probes and capture probes immobilized on a gold surface were monitored quantitatively by measuring the resonance wavelength in the visible waveband. The experimental results were consistent with numerical calculations. Although the SPR detection technique does not require the DNA to be labeled, we also evaluated fluorescently-labeled targets to verify the hybridization behavior of the AI-DNA. Changes in resonance were found to be linearly proportional to the amount of bound analyte. A wavelength interrogation-type SPR biosensor can be used for rapid measurement and high-throughput detection of highly pathogenic AI viruses.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.409-421
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• 2003

The hierarchical recursive local-correlation PIV algorithm with CBC (correlation based correction) method was employed to increase the spatial resolution of PIV results and to reduce error vectors. The performance of this new PIV algorithm was tested using synthetic images, PIV standard images of Visualization Society of Japan, real flows including ventilation flow inside a vehicle passenger compartment and wake behind a circular cylinder with riblet surface. As a result, most spurious vectors were suppressed by employing the CBC method, the hierarchical recursive correlation algorithm improved the sub-pixel accuracy of PIV results by decreasing the interrogation window size and Increased spatial resolution significantly. However, with recursively decreasing of interrogation window size, the SNR (signal-to-noise ratio) in the correlation plane was decreased and number of spurious vectors was increased. Therefore, compromised determination of optimal interrogation window size is required for given flow images, the performance of recursive algorithm is also discussed from a viewpoint of recovery ratio and error ratio in the paper.

• Smart Structures and Systems
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• v.20 no.3
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• pp.343-350
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• 2017

An experimental study is presented of the application of fiber Bragg grating (FBG) interrogation method based on optical time-domain reflectometery (OTDR) to monitoring strain in bent reinforced concrete beams. The results obtained with the OTDR-based method are shown to agree well with the direct spectral measurements. Strain sensitivity, resolution and measurement range amounted to $0.0028dB/{\mu}strain$; $30{\mu}strain$; $4000{\mu}strain$, correspondingly. Significant differences are observed in surface and inner deformations of the test beams which can be attributed to different mechanical properties of concrete and steel reinforcement. The prospects of using OTDR-based FBG interrogation technique in real-life applications are discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.173-181
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• 2000

Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface. This capability is very important because the defect of the surface requires the rework of the dies that causes a big loss in cost and delivery time. To simulate the reflection line test in the actual production line, a faster generation algorithm is presented. Among., various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate reflection lines on the trimmed NURBS surface. The generation of reflection lines is formulated as a surface-plane intersection problem, and solved by surface-contouring techniques. In addition, a modified reflection map is proposed to eliminate the discontinuity of reflection lines due to the configuration of the reflection map. A fast reflection line algorithm is developed utilizing an efficient traced contouring technique, and proved to be well suited for real-time quality-assessment task.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.8
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• pp.440-444
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• 2002

This paper presents an efficient and robust algorithm to compute the isophote of a surface of revolution. A surface of revolution can be decomposed to a set of cross-sectional circles. The surface normals along each cross-sectional circle form a cone. Using the characteristics of the normal vectors and the symmetric property of the surface of revolution, we propose a method to find the connected components of an isophote, which requires intersecting a planar curve(and its reflection) with two rays. Moreover, we propose a closed-form representation of an isophote as a parametric curve.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.160-171
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• 2001

Depending upon the method of the surface generation and the quality of the designed boundary curves, the resulting surfaces may have global or local irregularities in many cases. Thus, it would be necessary for the designer to evaluate the surface quality and to modify the surface. This is very important because the defect of the surface causes the rework of the dies, increasing cost and delivery time significantly. To simulate the reflection line test in the actual production line, a faster algorithm for generating reflection lines is presented. In this paper, among various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate the reflection lines on the trimmed NURBS surfaces. The derivation of reflection lines is formulated as a surface-plane intersection problem (Jung 1994) and is solved by surface-contouring techniques. Also, for eliminating the discontinuity of reflection lines due to the configuration of reflection map, a modified reflection map is proposed. An efficient traced contouring technique is utilized for the computational efficiency and proves to be well suited for the real-time quality-assessment task.

• Journal of Korea Water Resources Association
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• v.46 no.8
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• pp.821-831
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• 2013

Recently image velocimetries, including particle image velocimetry (PIV) and surface image velocimetry (SIV), are often used to measure flow velocities in laboratories and rivers. The most difficult point in using image velocimetries may be how to determine the sizes of the interrogation areas and the measurement uncertainties. Especially, it is a little hard for unskilled users to use these instruments, since any standardized measuring techniques or measurement uncertainties are not well evaluated. Sometimes the user's skill and understanding on the instruments may make a wide gap between velocity measurement results. The present study aims to evaluate image velocimetry's uncertainties due to the changes in the sizes of interrogation areas and searching areas with the error analyses. For the purpose, we generated 12 series of artificial images with known velocity fields and various numbers and sizes of particles. The analysis results showed that the accuracy of velocity measurements of the image velocimetry was significantly affected by the change of the size of interrogation area. Generally speaking, the error was reduced as the size of interrogation areas became small. For the same sizes of interrogation areas, the larger particle sizes and the larger number of particles resulted smaller errors. Especially, the errors of the image velocimetries were more affected by the number of particles rather than the sizes of them. As the sizes of interrogation areas were increased, the differences between the maximum and the minimum errors seemed to be reduced. For the size of the interrogation area whose average errors were less than 5%, the differences between the maximum and the minimum errors seemed a little large. For the case, in other words, the uncertainty of the velocity measurements of the image velocimetry was large. In the viewpoint of the particle density, the size of the interrogation area was small for large particle density cases. For the cases of large number of particle and small particle density, however, the minimum size of interrogation area became smaller.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.975-976
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• 2006

The passive type RFID (Radio Frequency Identification) System using Surface Acoustic Wave (SAW) tag at 900 MHz in the range of more than 1 m was fabricated. To improve interrogation range of the system propose a method to increase isolation between transmitter and receiver. This method using a direct conversion architecture achieves a leakage rejection of 10 dB increased compared with conventional system. Measured interrogation range is more than 1 m.