• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.3
• /
• pp.137-147
• /
• 2020

This paper proposes printed bow-tie antennas with 3 ~ 5 GHz broadband characteristics were proposed for testing the electromagnetic immunity of automotive electrical components in the 5G frequency band. The antenna get -10 dB bandwidth in the 2.75 ~ 6 GHz frequency band and the broadside radiation pattern with S₁₁ characteristic of -16.2 dB at resonant frequency. In testing electromagnetic immunity in the 5G mobile communication frequency band, the VSWR characteristic remained below 2.1, forming a level of 1 W as proposed by international standards. As a result, it is confirmed that the proposed antenna can be applied to antenna testing for electromagnetic immunity verification in the 5G mobile communication frequency band.

• Journal of Korea Multimedia Society
• /
• v.4 no.3
• /
• pp.247-256
• /
• 2001

Digital watermarking is a copyright protection technique for digital images which embed a code into the digital data so the data is marked. Watermarking techniques previously deal with on-line digital data and have been developed to withstand digital attacks such image processing, compression and geometric transformation. In this paper we propose a novel method of embedding watermarks in printed images. In the proposed algorithm, watermark is embedded in a dithered binary image by comparing the $2\times{2}$ blocks of the counting array is the number of 1 (WHITE) in the $16\times{16}$ blocks of the dithered binary image with predefined reference block pattern, which is generated by watermark values. The proposed algorithm is able to provide more information at a watermark because the proposed algorithm use both '1'and '0' as watermark values. The watermark information is detected by comparing the watermark which is reconstructed from the image which is embedded watermark with the original watermark which is embedded in a binary image. The performance of the proposed algorithm is compared with that of the conventional watermark embedding algorithm for printed images by detecting watermark for scan images.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.27 no.5
• /
• pp.256-262
• /
• 2017

Digital ink-jet printing technology using ceramic ink, which is thermally stable at high temperature above $1000^{\circ}C$, has an advantage of eco-friendly process applicable to manufacturing products with an excellent durability and various designs. Recently, replacement from conventional manufacturing process to digital process using ink-jet printing technique has been significantly accelerated in ceramic tile industry. In this study, we investigated ink-jet printability of ceramic ink on ceramic tile. Cyan, magenta, yellow, black ceramic inks, which are digital primary color of ink-jet printing, were printed on glazed surface of ceramic tiles, and their printabilities were comparatively analyzed. High temperature sintering process is generally required for manufacturing ceramic products, thus effect of sintering process on printed pattern of ceramic ink was also investigated by analyzing ink penetration depth and ink dot area.

• Journal of Sensor Science and Technology
• /
• v.31 no.2
• /
• pp.85-89
• /
• 2022

We investigated a pH sensor using an Indium tin oxide (ITO) nanoparticle (NP) film printed on a flexible substrate. First, the printing precision and mechanical stability of the ITO-printed film were investigated. In particular, the factors that influence the crystallinity of ITO films were studied using X-ray diffraction pattern analysis. The response of the ITO pH sensor was calibrated using a series of standard pH solutions (pH 3-11). The pH values of various specimens were measured using an ITO pH sensor, and the results were compared with those of various pH measurement methods. As a result of the experiment, the maximum error was approximately ± 0.04 pH (0.4 %) at pH 9, which indicated that the ITO pH sensor is highly suitable for pH measurement. Finally, we used the ITO pH sensor to the measure of general specimens such as solvents and beverages and compared the results in comparison with those obtained from several conventional methods.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.42 no.4
• /
• pp.689-707
• /
• 2018

This study reviewed the differences among Onggis made in Jeju and other areas, developed creative textile designs and cultural products, and conducted the consumer evaluation of developed products. First, the 1,063 photos of Onggis made before the first part of the 20th century were collected and the unique differences of Jeju Onggis were confirmed through the observation of collected photos. Second, based on the uniqueness of Jeju Onggis, the eight pieces of Jeju Onggis were selected from the photos and used as pattern design motifs. Nine basic patterns were drawn and ten textile designs were created using the basic patterns. Third, the 16 pieces of textile products were made with cotton fabrics on which the textile designs were printed. Four mugs and four tumblers with printed patterns were also made. Finally, 64 students evaluated the developed products using a 7-point scale. As a result, folksy atmosphere, uniqueness, usage as a Jeju souvenir and at local restaurants, and the role of fostering concern for Jeju Onggi were highly evaluated but aesthetics was rated relatively low. Most of the developed products were highly preferred and recommended as Jeju souvenirs or for local restaurants.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1537-1541
• /
• 2010

An inkjet printing system for printed electronics was developed. In this study, a printing algorithm was mainly discussed. In order to print a pattern image at a target location, we developed a hardware and software algorithm for determining the distances between a substrate camera and the selected nozzles. We implemented a vector-printing algorithm where AutoCAD dxf file was used for XY motion control and for printing. We also developed printing method using bitmap images. The technical issues in using CAD drawings and bitmap images were discussed.

• Journal of Sensor Science and Technology
• /
• v.28 no.6
• /
• pp.390-394
• /
• 2019

This paper presents an inkjet-printed plastic force sensor using PEDOT:PSS. Using a piezoelectric-type inkjet printer, the force sensor was manufactured by printing PEDOT:PSS ink onto a polyimide (PI) substrate film. Applying a vertical force of 0 to 100 N to the force sensor on the PI substrate with a thickness of 64 mm, the resistance of the force sensor increased in proportion to the input force by the length deformation of the PI substrates and the sensor pattern. As a result, the fabricated sensor has a characteristic of 0.001% /N with a linearity of 99.38%. In addition, as the thickness of the PI substrate film increased, the sensitivity of the sensor increased linearly. The fabricated force sensor is expected to be applied to industrial sites and healthcare fields.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.1100-1103
• /
• 1987

In this paper, we report a method for the primitive segments extraction from printed Korean characters without thinning as a preliminary stage to design an efficient recognition system. The primitive segments are defined by fundamental subpatterns which are vertical(I), right sloping(/), left. sloping(\). horizontal(-), and circular segment(o). The circular segment among the five kinds of segment is different from the others in geometrical properties. Therefore, at first, the circular segment is extracted by using the closed circle of the inner boundary and the geometrical characteristics of its outer. Next, linear segments are separated from the character pattern by means of a directional coding method. Finally, primitive segments are extracted from each set of linear segments by using a projection profile which involves the fact whether the segment has branches or not. The experimental results show that this method reduces computation time and storage space in comparision with the existing methods.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.4
• /
• pp.22-25
• /
• 2003

High series resistance due to the presence of glass frit is one of the major problems for screen printed silicon solar cells. Cells having electrical parameters below the prescribed values are usually rejected during solar module fabrication. Therefore, it is highly desirable to improve the electrical parameters of the silicon solar cells and thereby to increase the overall production yield. It was observed that, the performance of low quality mono-crystalline silicon solar cells made by standard screen printing technology could be improved remarkably by novel surface treatment. We have chemically treated the surface using sodium hydroxide (NaOH) and silver nitrate ($AgNO_3$) solutions. NaOH treatment helps to reduce the series resistance by decreasing the presence of excess glass frit on the top silver grid contact. The $AgNO_3$ treatment is used to reduce the series resistance comes from the deposition of silver on the grids by filling the holes present (if any) within the grid pattern.

• Journal of the Optical Society of Korea
• /
• v.15 no.4
• /
• pp.362-367
• /
• 2011

Organic ($Alq_3$) film, which was coated on a donor plate, was transferred to an organic light emitting diode (OLED) substrate with help of heat generated by a dithering laser beam. The laser beam was diffracted in an acousto-optic modulator (AOM), then focused on the laser-to-heat converting layer of the donor plate; the focused spot followed trajectories guided by rotation of a Galvano-mirror. Three different functional waveforms, sine wave, square wave, and saw tooth wave were applied to the AOM as modulation signal to generate the dithering beam. The fluorescence microscope images of the donor plate showed that the patterns of removed $Alq_3$ film were affected considerably by the modulation waveforms and the phase difference between adjacent dithering beams. Further, the printed images of Alq3 film on the OLED substrate were different from the patterns of removed Alq3 film. Atomic force microscope images indicated that not only direct transfer but also deposition by sublimated vapor of Alq3 contributed to the pattern formation. Printed patterns affected considerably the electricity-to-light conversion characteristics of OLEDs. For uniform transfer, not only the phase relation of dithering beam lines but also adequate waveform were important.