• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.197-204
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• 1996

We attempt to classifing method of micro-landform on the alluvial plain, such as natural-levee, backmarsh and alluvial fan, using false color composite of Landsat Thematic Mapper image. The study area is Kumho River Basin on the southeastern part of Korea peninsula. The most effective image for micro-landform classification is the false color composite of band 2, 3 and 4 with blue, green and red filtering. The most favorable time is the middle third of November, because of the density differentiation of green vegetation in most great. In this time the paddy field on the back-marsh is bare by rice harvesting. But on the natural levee the green vegetation, such as vegetables and lower herbs under fruit tree, remain relatively more. On the alluvial fan, the green vegetation condition is medium. For the verification of the micro-landform classification, we employed the field survey and grain size analysis of the deposition of each micro-landform on the sample area. It is clarified that the classification method of micro-landform on the alluvial plain using the Landsat TM image is relatively useful.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.393-399
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• 2011

A defect analysis program of the composite motor case was developed to apply the ultrasonic signal processing method on basis of the ultrasonic pulse-echo method and the defects of FRP delamination and FRP/Rubber disbond in the composite motor case could be quantitatively measured. The defects detected in the composite motor case were in agreement with the results measured with the computed tomography and video microscope. This paper was described about the development process of the defect analysis program to convert the ultrasonic test data into the C-Scan image.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.6
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• pp.456-461
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• 1999

In this study, the characteristics of Ultrasonic Transducer fabricated with PZT-Polymer 1-3 type piezoelectric ceramic/polymer composite are investigated. 3-D underwater object restoration using the self-made ultrasonic transducer and modified SCL(Simple Competitive Learning) neural network was presented. The ultrasonic transducer was satisfied with the required condition of commerical ultrasonic transducer in underwater. The modified SCL neural network using the acquired object data $16\times16$ low resolution image was used for object restoration of $32\times32$ high resolution image. The experimental results have shown that the ultrasonic transducer fabricated with PZT-Polymer 1-3 type piezoelectric ceramic/polymer composite could be applied for SONAR system.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.86-91
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• 2010

Among various fuel cells, solid oxide fuel cells (SOFCs) offer the highest energy efficiency, when taking into account the thermal recycling of waste heat at high temperature. However, the highest efficiency and lowest pollution for a SOFC can be achieved through the sophisticated control of its constituent components such as electrodes, electrolytes, interconnects and sealing materials. The electrochemical conversion efficiency of a SOFC is particularly dependent upon the performance of its electrode materials. The electrode materials should meet highly stringent requirements to optimize cell performance. In particular, both mass and charge transport should easily occur simultaneously through the electrode structure. Matter transport or charge transport is critically related to the configuration and spatial disposition of the three constituent phases of a composite electrode, which are the ionic conducting phase, electronic conducting phase, and the pores. The current work places special emphasis on the quantification of this complex microstructure of composite electrodes. Digitized images are exploited in order to obtain the quantitative microstructural information, i.e., the size distributions and interconnectivities of each constituent component. This work reports regarding zirconia-based composite electrodes.

• Composites Research
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• v.33 no.3
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• pp.125-132
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• 2020

The polymerization shrinkage behavior of dimethacrylate-based composite (Clearfil AP-X, Kuraray) and silorane-based composite (Filtek P90, 3M ESPE) used for dental composite restorations was measured using digital image correlation method. The stress distribution on the surface of specimen was calculated by finite element analysis with equivalent elastic modulus and was compared with the measured shrinkage distribution. Camera images were monitored by a CCD camera during and after the irradiation of light. As a result of the DIC analysis, a non-uniform shrinkage distribution was observed in both composite resins, and the resin core inside the ring specimen had free flowability, leading to in greater shrinkage strain than the resin/ring interfacial region. It was observed that as the distance from the center of the resin increased, the radial average shrinkage strain decreased. The radial average shrinkage strain during light irradiation occurred to be 33% for P90 and 57% for AP-X of the entire strain at the end of the test. The shrinkage behavior of P90 and AP-X was measured to be significantly different from each other during light irradiation. In the resin near the resin/ring interface, it was confirmed that the tensile strain rapidly formed to increase after light irradiation, causing a tensile stressed, interface weak.

• Steel and Composite Structures
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• v.23 no.6
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• pp.727-736
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• 2017

The application of carbon fiber reinforced polymer (CFRP) in steel structures primarily includes two categories, i.e., the bond-critical application and the contact-critical application. Debonding failure and buckling failure are the main failure modes for these two applications. Conventional electrometric techniques may not provide precise results because of the limitations associated with single-point contact measurements. A nondestructive full-field measurement technique is a valuable alternative to conventional methods. In this study, the digital image correlation (DIC) technique was adopted to investigate the bond behavior and buckling behavior of CFRP-steel composite members. The CFRP-to-steel bonded joint and the CFRP-strengthened square hollow section (SHS) steel column were tested to verify the suitability of the DIC technique. The stereo-DIC technique was utilized to measure continuous deformation. The bond-slip relationship of the CFRP-to-steel interface was derived using the DIC data. Additionally, a multi-camera DIC system consisting of four stereo-DIC subsystems was proposed and applied to the compressive test of CFRP-strengthened SHS steel column. The precise buckling location and CFRP delamination of the CFRP-strengthened SHS steel column were identified. The experimental results confirm that the stereo-DIC technique can provide effective measurements for investigating the behaviors of CFRP-steel composite members.

• Restorative Dentistry and Endodontics
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• v.49 no.1
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• pp.7.1-7.11
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• 2024

Objectives: This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One. Materials and Methods: Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE₀₀) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05). Results: The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique. Conclusions: Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.1-6
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• 2021

In this paper, an efficient implementation of AES encryption algorithm is presented for CCTV image security using C# language. In this approach, an efficient S-Box is first designed for reducing the computation time which is required in each round process of AES algorithm, and then an CCTV image security system is implemented on the basis of this algorithm on a composite field GF(((22)2)2). In addition, the shared S-Box structure is designed for realizing the minimized memory space, which is used in each round transformation and key scheduling processes. Through performance evaluation, it was confirmed that the proposed method is more efficient than the existing method. The proposed CCTV system in C# language using Visual studio 2010.

• Korean Journal of Remote Sensing
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• v.35 no.4
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• pp.535-544
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• 2019

This study demonstrated the ability of a Landsat-8 OLI multispectral data to identify and delineate hydrothermal alteration zones around auriferous prospects within the crystalline basement, North-western Nigeria. Remote sensing techniques have been widely used in lithological, structural discrimination and alteration rock delineation, and in general geological studies. Several artisanal mining activities for gold deposit occur in the surrounding areas within the basement complex and the search for new possible mineralized zones have heightened in recent times. Systematic Landsat-8 OLI data processing methods such as colour composite, band ratio and minimum noise fraction were used in this study. Colour composite of band 4, 3 and 2 was displayed in Red-Green-Blue colour image to distinguish lithologies. Band ratio ${\frac{4}{2}}$ image displayed in red was used to highlight ferric-ion bearing minerals(hematite, goethite, jarosite) associated with hydrothermal alteration, band ratio ${\frac{5}{6}}$ image displayed in green was used to highlight ferrous-ion bearing minerals such as olivine, amphibole and pyroxenes, while ratio ${\frac{6}{7}}$ image displayed in blue was used to highlight clay minerals, micas, talc-carbonates, etc. Band rationing helped to reduce the topographic illumination effect within images. The result of this study showed the distribution of the lithological units and the hydrothermal alteration zone which can be further prospected for mineral reserves.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.1-8
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• 2007

The objective of the present work is to characterize design parameters of solid propellant ignitor for composite, double base, and nitramine propellants using arc image furnace. Arc image furnace and fiber optics surface reflectometer were used to measure ignition delay time and reflected optical energy of several compositions of composite, double base and nitramine base rocket propellant at different pressure levels each other. The order of ignitability was double base > composite> nitramine propellants at initial pressure of over 75 psia. The highest ignition energy was needed to ignite nitramine propellant, however, the ignition delay time decreased abruptly as the pressure increased up to the range of $75{\sim}400$ psia. The absorbtion of radiation energy could be increased by the addition of small amount of opacifiers as carbon black, ZrC, WC and burning catalyst.